Publications
Achieving system-level benefits in solar photovoltaic-rich distribution feeders through intelligent control of inverters. Dalal, D.; Pal, A.; and Ayyanar, R. IET Renewable Power Generation. 2026. Accepted for publication
@article{dalal2026achievingsystemlevel, title={Achieving system-level benefits in solar photovoltaic-rich distribution feeders through intelligent control of inverters}, author={Dalal, D. and Pal, Anamitra and Ayyanar, Raja}, journal={IET Renewable Power Generation}, year={2026}, note={Accepted for publication} }
A constrained formulation for simultaneous line parameter estimation and instrument transformer calibration. Varghese, A. C.; Anguluri, R.; and Pal, A. IEEE Transactions on Power Delivery. 2026. Accepted for publication
@article{varghese2026constrainedformulation, title={A constrained formulation for simultaneous line parameter estimation and instrument transformer calibration}, author={Varghese, Antos Cheeramban and Anguluri, Rajasekhar and Pal, Anamitra}, journal={IEEE Transactions on Power Delivery}, year={2026}, note={Accepted for publication} }
Enhanced analysis of critical power system events using merged and correlated PoW and PMU data. Paudel, Y.; Vittal, V.; Pal, A.; Joshi, D.; Venkatasubramanian, M. V.; Karmacharya, A.; and Kezunovic, M. In IEEE 5th International Conference on Smart Grid Synchronized Measurements and Analytics (SGSMA), Santiago de Chile, Chile, Jun. 2026. Accepted for presentation, 1–4 Jun. 2026
@inproceedings{paudel2026enhancedanalysis, title={Enhanced analysis of critical power system events using merged and correlated PoW and PMU data}, author={Paudel, Y. and Vittal, V. and Pal, Anamitra and Joshi, D. and Venkatasubramanian, M. V. and Karmacharya, A. and Kezunovic, M.}, booktitle={IEEE 5th International Conference on Smart Grid Synchronized Measurements and Analytics (SGSMA)}, address={Santiago de Chile, Chile}, month={Jun.}, year={2026}, note={Accepted for presentation, 1--4 Jun. 2026} }
Impact of Work Schedule Flexibility on EV Hosting Capacity: Insights from Analyzing Field Data. Iorio, M.; Golgol, M.; and Pal, A. 2026.
@misc{2026.1, title={Impact of Work Schedule Flexibility on EV Hosting Capacity: Insights from Analyzing Field Data}, author={Marco Iorio and Mohammad Golgol and Anamitra Pal}, year={2026}, eprint={2603.06943}, archivePrefix={arXiv}, primaryClass={eess.SY}, url={https://arxiv.org/abs/2603.06943}, }
Maximizing Grid Support of Electric Vehicles by Coordinating Residential Charging: Insights From an Arizona Feeder Case Study. GOLGOL, M.; Pal, A.; Vittal, V.; Kessinger, C.; Palomino, E.; and Girardi, K. IEEE Open Access Journal of Power and Energy, 13: 27-38. 2026.
@ARTICLE{2026.2, author={GOLGOL, Mohammad and Pal, Anamitra and Vittal, Vijay and Kessinger, Christine and Palomino, Ernest and Girardi, Kyle}, journal={IEEE Open Access Journal of Power and Energy}, title={Maximizing Grid Support of Electric Vehicles by Coordinating Residential Charging: Insights From an Arizona Feeder Case Study}, year={2026}, volume={13}, number={}, pages={27-38}, keywords={Transformers;Batteries;State of charge;Electric vehicle charging;Distance measurement;Reviews;Optimization;Load modeling;Connectors;Automobiles;Charging coordination;electric vehicle charging;hosting capacity;residential charging}, doi={10.1109/OAJPE.2025.3645250}}
System-wide instrument transformer calibration and line parameter estimation using PMU data. Varghese, A. C.; and Pal, A. IEEE Transactions on Power Delivery, 41(1): 115–128. Feb. 2026.
@article{varghese2026systemwideinstrumenttransformercalibration, title={System-wide instrument transformer calibration and line parameter estimation using PMU data}, author={Varghese, Antos Cheeramban and Pal, Anamitra}, journal={IEEE Transactions on Power Delivery}, volume={41}, number={1}, pages={115--128}, month={Feb.}, year={2026}, url={https://arxiv.org/abs/2503.21202} }
Transfer Learning on Synchrophasor Data for Automatically Detecting and Classifying Critical Power System Events. Mohamed, T.; Joshi, D.; Paudel, Y.; Pal, A.; Kezunovic, M.; Venkatasubramanian, M. V.; Vittal, V.; and Torresan, G. IEEE Transactions on Industry Applications,1-12. 2025.
@ARTICLE{11074313, author={Mohamed, Taif and Joshi, Deepak and Paudel, Yadunandan and Pal, Anamitra and Kezunovic, Mladen and Venkatasubramanian, Mani V. and Vittal, Vijay and Torresan, Gilles}, journal={IEEE Transactions on Industry Applications}, title={Transfer Learning on Synchrophasor Data for Automatically Detecting and Classifying Critical Power System Events}, year={2025}, volume={}, number={}, pages={1-12}, keywords={Phasor measurement units;Oscillators;Feature extraction;Data models;Frequency measurement;Power systems;Adaptation models;Transfer learning;Support vector machines;Power system stability;Event analysis;Faults;Frequency events;Oscillations;Synchrophasors;Transfer learning}, doi={10.1109/TIA.2025.3587209}}
A Preventive-Corrective Scheme for Ensuring Power System Security During Active Wildfire Risks. Sahoo, S.; and Pal, A. IEEE Open Access Journal of Power and Energy,1-1. 2025.
Linear State Estimation in Presence of Bounded Uncertainties: A Comparative Analysis. Das, A.; Sharma, A.; and Pal, A. 2025.
@misc{das2025linearstateestimationpresence, title={Linear State Estimation in Presence of Bounded Uncertainties: A Comparative Analysis}, author={Ayan Das and Anushka Sharma and Anamitra Pal}, year={2025}, eprint={2510.16693}, archivePrefix={arXiv}, primaryClass={eess.SY}, url={https://arxiv.org/abs/2510.16693}, }
Topology-Aware Graph Neural Network-Based State Estimation for PMU-Unobservable Power Systems. Moshtagh, S.; Azimian, B.; Golgol, M.; and Pal, A. IEEE Transactions on Power Systems,1-14. 2025.
@ARTICLE{2025.1, author={Moshtagh, Shiva and Azimian, Behrouz and Golgol, Mohammad and Pal, Anamitra}, journal={IEEE Transactions on Power Systems}, title={Topology-Aware Graph Neural Network-Based State Estimation for PMU-Unobservable Power Systems}, year={2025}, volume={}, number={}, pages={1-14}, keywords={Phasor measurement units;Topology;Power systems;Vectors;Noise;Graph neural networks;Transmission line matrix methods;Network topology;Training;State estimation;Graph neural network;phasor measurement unit;state estimation;topology change;unobservability}, doi={10.1109/TPWRS.2025.3572848}, url={https://arxiv.org/abs/2506.03493}, }
A Practical Approach Towards Inertia Estimation Using Ambient Synchrophasor Data. Sharma, A.; Pal, A.; Anguluri, R.; and Chakraborty, T. 2025.
@misc{2025.2, title={A Practical Approach Towards Inertia Estimation Using Ambient Synchrophasor Data}, author={Anushka Sharma and Anamitra Pal and Rajasekhar Anguluri and Tamojit Chakraborty}, year={2025}, eprint={2505.02978}, archivePrefix={arXiv}, primaryClass={eess.SY}, url={https://arxiv.org/abs/2505.02978}, }
Improving photovoltaic hosting capacity of distribution networks with coordinated inverter control: A case study of the EPRI J1 feeder. Dalal, D.; Sondharangalla, M.; Ayyanar, R.; and Pal, A. IET Renewable Power Generation, 19(1): e13181. 2025.
@article{2025.3, author = {Dalal, Dhaval and Sondharangalla, Madhura and Ayyanar, Rajapandian and Pal, Anamitra}, title = {Improving photovoltaic hosting capacity of distribution networks with coordinated inverter control: A case study of the EPRI J1 feeder}, journal = {IET Renewable Power Generation}, volume = {19}, number = {1}, pages = {e13181}, keywords = {invertors, voltage control, distribution networks, power system control}, doi = {https://doi.org/10.1049/rpg2.13181}, url = {https://ietresearch.onlinelibrary.wiley.com/doi/abs/10.1049/rpg2.13181}, eprint = {https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/rpg2.13181}, abstract = {Abstract Adding photovoltaic (PV) systems in distribution networks, while desirable for reducing the carbon footprint, can lead to voltage violations under high solar-low load conditions. The inability of traditional volt-VAr control in eliminating all the violations is also well-known. This article presents a novel coordinated inverter control methodology that leverages system-wide situational awareness to significantly improve hosting capacity (HC). The methodology employs a real-time voltage-reactive power (VQ) sensitivity matrix in an iterative linear optimizer to calculate the minimum reactive power intervention from PV inverters needed for mitigating over-voltage without resorting to active power curtailing or requiring step voltage regulator setting changes. The algorithm is validated using the EPRI J1 feeder under an extensive set of realistic use cases and is shown to provide 3x improvement in HC under all scenarios.}, year = {2025} }
Abstract Adding photovoltaic (PV) systems in distribution networks, while desirable for reducing the carbon footprint, can lead to voltage violations under high solar-low load conditions. The inability of traditional volt-VAr control in eliminating all the violations is also well-known. This article presents a novel coordinated inverter control methodology that leverages system-wide situational awareness to significantly improve hosting capacity (HC). The methodology employs a real-time voltage-reactive power (VQ) sensitivity matrix in an iterative linear optimizer to calculate the minimum reactive power intervention from PV inverters needed for mitigating over-voltage without resorting to active power curtailing or requiring step voltage regulator setting changes. The algorithm is validated using the EPRI J1 feeder under an extensive set of realistic use cases and is shown to provide 3x improvement in HC under all scenarios.
Design and Validation of a Very Low-Power Phasor Measurement Unit for the Distribution System. Lythgoe, Z. J.; Long, T. F.; Buchholz, M. J.; Livernois, A. R.; Kanuteh, K.; Allee, D. R.; Pal, A.; Graham, I. R.; and Drummond, Z. D. IEEE Transactions on Industry Applications, 61(2): 3553-3562. 2025.
@ARTICLE{2025.4, author={Lythgoe, Zachary J. and Long, Thomas F. and Buchholz, Michael J. and Livernois, Anthony R. and Kanuteh, Kebba and Allee, David R. and Pal, Anamitra and Graham, Ian R. and Drummond, Zachary D.}, journal={IEEE Transactions on Industry Applications}, title={Design and Validation of a Very Low-Power Phasor Measurement Unit for the Distribution System}, year={2025}, volume={61}, number={2}, pages={3553-3562}, keywords={Phasor measurement units;Sensors;Voltage measurement;Low-pass filters;Conductors;Power demand;Field programmable gate arrays;Batteries;Signal processing algorithms;Sensor arrays;Digital signal processing;distribution system;field-programmable gate array (FPGA);phasor measurement unit (PMU);smart grid}, doi={10.1109/TIA.2024.3524494}}
Enhanced Dynamic Line Rating Forecasting Under Cyber-Attacks via Incremental Learning Frameworks. Moradzadeh, A.; Mouhammadpourfard, M.; Pol, S.; Pal, A.; Malik, M.; and Srivastava, A. In 2025 IEEE Texas Power and Energy Conference (TPEC), pages 1-6, 2025.
@INPROCEEDINGS{2025.5, author={Moradzadeh, Arash and Mouhammadpourfard, Mostafa and Pol, Suhas and Pal, Anamitra and Malik, Mayank and Srivastava, Anurag}, booktitle={2025 IEEE Texas Power and Energy Conference (TPEC)}, title={Enhanced Dynamic Line Rating Forecasting Under Cyber-Attacks via Incremental Learning Frameworks}, year={2025}, volume={}, number={}, pages={1-6}, keywords={Adaptation models;Accuracy;Incremental learning;Wind speed;Bidirectional long short term memory;Predictive models;Data models;Forecasting;Faces;Cyberattack;Cyber-security;dynamic line rating;forecasting;incremental learning;online learning;transmission line}, doi={10.1109/TPEC63981.2025.10907165}}
Analytical Verification of Performance of Deep Neural Network Based Time-Synchronized Distribution System State Estimation. Azimian, B.; Moshtagh, S.; Pal, A.; and Ma, S. Journal of Modern Power Systems and Clean Energy, 12(4): 1126-1134. 2024.
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@ARTICLE{10345460, author={Azimian, Behrouz and Moshtagh, Shiva and Pal, Anamitra and Ma, Shanshan}, journal={Journal of Modern Power Systems and Clean Energy}, title={Analytical Verification of Performance of Deep Neural Network Based Time-Synchronized Distribution System State Estimation}, year={2024}, volume={12}, number={4}, pages={1126-1134}, keywords={Perturbation methods;Robustness;Artificial neural networks;Power systems;Phasor measurement units;Neurons;Training;Deep neural network (DNN);distribution system state estimation (DSSE);mixed-integer linear programming (MILP);robustness;trustworthiness}, doi={10.35833/MPCE.2023.000432}}
Design and Validation of a Very Low-Power Phasor Measurement Unit. Lythgoe, Z. J.; Long, T. F.; Buchholz, M. J.; Livernois, A. R.; Kanuteh, K.; Allee, D. R.; Pal, A.; Graham, I. R.; and Drummond, Z. D. In 2024 IEEE Texas Power and Energy Conference (TPEC), pages 1-6, 2024.
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@INPROCEEDINGS{10472187, author={Lythgoe, Zachary J. and Long, Thomas F. and Buchholz, Michael J. and Livernois, Anthony R. and Kanuteh, Kebba and Allee, David R. and Pal, Anamitra and Graham, Ian R. and Drummond, Zachary D.}, booktitle={2024 IEEE Texas Power and Energy Conference (TPEC)}, title={Design and Validation of a Very Low-Power Phasor Measurement Unit}, year={2024}, volume={}, number={}, pages={1-6}, keywords={Power demand;Power measurement;Costs;Phasor measurement units;Hardware;Power system reliability;Synchronization;Distribution system;Field-programmable gate array (FPGA);Phasor measurement unit (PMU)}, doi={10.1109/TPEC60005.2024.10472187}}
Deep Neural Network-Based State Estimator for Transmission System Considering Practical Implementation Challenges. Varghese, A. C.; Shah, H.; Azimian, B.; Pal, A.; and Farantatos, E. Journal of Modern Power Systems and Clean Energy,1-13. 2024.
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@ARTICLE{10495872, author={Varghese, Antos Cheeramban and Shah, Hritik and Azimian, Behrouz and Pal, Anamitra and Farantatos, Evangelos}, journal={Journal of Modern Power Systems and Clean Energy}, title={Deep Neural Network-Based State Estimator for Transmission System Considering Practical Implementation Challenges}, url = {https://ieeexplore.ieee.org/document/10495872}, year={2024}, volume={}, number={}, pages={1-13}, keywords={Phasor measurement units;State estimation;Topology;Noise;Artificial neural networks;Power systems;Bayes methods;Deep neural network (DNN);Phasor measurement unit (PMU);State estimation;Unobservability}, doi={10.35833/MPCE.2023.000997}}
Stability-Constrained Settings of Directional Overcurrent Relays With Shifted User-Defined Characteristics for Distribution Networks With DERs. Sheta, A. N.; Sedhom, B. E.; Pal, A.; Moursi, M. S. E.; and Eladl, A. A. IEEE Transactions on Power Delivery, 39(4): 2401-2413. 2024.
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@ARTICLE{10536661, author={Sheta, Ahmed N. and Sedhom, Bishoy E. and Pal, Anamitra and Moursi, Mohamed Shawky El and Eladl, Abdelfattah A.}, journal={IEEE Transactions on Power Delivery}, title={Stability-Constrained Settings of Directional Overcurrent Relays With Shifted User-Defined Characteristics for Distribution Networks With DERs}, year={2024}, volume={39}, number={4}, pages={2401-2413}, keywords={Relays;Power system stability;Circuit faults;Stability criteria;Circuit stability;Transient analysis;Fault currents;Critical clearing time;directional overcurrent relay;microgrid protection;relay coordination;and transient stability}, doi={10.1109/TPWRD.2024.3403921}}
Automated Detection and Classification of Critical Power System Events using ML on PMU Data. Mohamed, T.; Kezunovic, M.; Paudel, Y.; Vittal, V.; Pal, A.; Joshi, D.; Menuka, K.; Venkatasubramanian, M. V.; and Torresan, G. In 2024 International Conference on Smart Grid Synchronized Measurements and Analytics (SGSMA), pages 1-6, 2024.
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@INPROCEEDINGS{10571526, author={Mohamed, T. and Kezunovic, M. and Paudel, Y. and Vittal, V. and Pal, A. and Joshi, D. and Menuka, Kc and Venkatasubramanian, M. V. and Torresan, G.}, booktitle={2024 International Conference on Smart Grid Synchronized Measurements and Analytics (SGSMA)}, title={Automated Detection and Classification of Critical Power System Events using ML on PMU Data}, year={2024}, volume={}, number={}, pages={1-6}, keywords={Training;Machine learning algorithms;Feature extraction;Phasor measurement units;Real-time systems;Data models;Classification algorithms;Event detection;Faults;Machine learning;Oscillations;Phasor measurement units}, doi={10.1109/SGSMA58694.2024.10571526}}
Cut-set and Stability Constrained Optimal Power Flow for Resilient Operation During Wildfires. Sahoo, S.; and Pal, A. In 2024 IEEE Kansas Power and Energy Conference (KPEC), pages 1-6, 2024.
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@INPROCEEDINGS{10676146, author={Sahoo, Satyaprajna and Pal, Anamitra}, booktitle={2024 IEEE Kansas Power and Energy Conference (KPEC)}, title={Cut-set and Stability Constrained Optimal Power Flow for Resilient Operation During Wildfires}, year={2024}, volume={}, number={}, pages={1-6}, url={https://ieeexplore.ieee.org/abstract/document/10676146}, keywords={Wildfires;Contingency management;Power system dynamics;Power system stability;Stability analysis;Generators;Numerical models;Contingency analysis;Cut-set saturation;Optimal power flow;Static security;Transient stability;Wildfire}, doi={10.1109/KPEC61529.2024.10676146}}
Localizing Single and Multiple Oscillatory Sources: A Frequency Divider Approach. Anguluri, R.; and Pal, A. In 2024 IEEE Power & Energy Society General Meeting (PESGM), pages 1-5, 2024.
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@INPROCEEDINGS{10689076, author={Anguluri, Rajasekhar and Pal, Anamitra}, booktitle={2024 IEEE Power & Energy Society General Meeting (PESGM)}, title={Localizing Single and Multiple Oscillatory Sources: A Frequency Divider Approach}, year={2024}, volume={}, number={}, pages={1-5}, keywords={Location awareness;Measurement units;Wind power generation;Position measurement;Frequency conversion;Phasor measurement units;Frequency measurement;Power systems;Matrix converters;Oscillators;Forced oscillations;Frequency divider;Phasor measurement unit;Sparsity;Total least squares}, doi={10.1109/PESGM51994.2024.10689076}}
Analyzing Cross-Phase Effects of Reactive Power Intervention on Distribution Voltage Control. Dalal, D.; Pal, A.; and Ayyanar, R. In 2024 IEEE Power & Energy Society General Meeting (PESGM), pages 1-5, 2024.
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@INPROCEEDINGS{10689150, author={Dalal, Dhaval and Pal, Anamitra and Ayyanar, Raja}, booktitle={2024 IEEE Power & Energy Society General Meeting (PESGM)}, title={Analyzing Cross-Phase Effects of Reactive Power Intervention on Distribution Voltage Control}, year={2024}, volume={}, number={}, pages={1-5}, keywords={Photovoltaic systems;Reactive power;Analytical models;Sensitivity;Absorption;System performance;Prevention and mitigation;Inverters;Voltage control;Cross-phase effects;Photovoltaic penetration;Reactive power intervention;Voltage control}, doi={10.1109/PESGM51994.2024.10689150}}
Machine-Learning-Based Adaptive Settings of Directional Overcurrent Relays With Double-Inverse Characteristics for Stable Operation of Microgrids. Sheta, A. N.; Sedhom, B. E.; Pal, A.; Moursi, M. S. E.; and Eladl, A. A. IEEE Transactions on Industrial Informatics,1-10. 2024.
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@ARTICLE{10691893, author={Sheta, Ahmed N. and Sedhom, Bishoy E. and Pal, Anamitra and Moursi, Mohamed Shawky El and Eladl, Abdelfattah A.}, journal={IEEE Transactions on Industrial Informatics}, title={Machine-Learning-Based Adaptive Settings of Directional Overcurrent Relays With Double-Inverse Characteristics for Stable Operation of Microgrids}, year={2024}, volume={}, number={}, pages={1-10}, keywords={Relays;Stability criteria;Transient analysis;Protection;Linear programming;Fault currents;Standards;Adaptive protection;clustering;critical clearing time (CCT);microgrid protection;relay coordination;self-organizing map (SOM);unsupervised machine learning (UML)}, doi={10.1109/TII.2024.3455349}}
Creating Temporally Correlated High-Resolution Profiles of Load Injection Using Constrained Generative Adversarial Networks. Shah, H. G.; Azimian, B.; and Pal, A. In 2024 56th North American Power Symposium (NAPS), pages 1-6, 2024.
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@INPROCEEDINGS{10741806, author={Shah, Hritik Gopal and Azimian, Behrouz and Pal, Anamitra}, booktitle={2024 56th North American Power Symposium (NAPS)}, title={Creating Temporally Correlated High-Resolution Profiles of Load Injection Using Constrained Generative Adversarial Networks}, year={2024}, volume={}, number={}, pages={1-6}, keywords={Training;Training data;Generative adversarial networks;Smart meters;Convex functions;Real-time systems;Velocity measurement;Voltage control;State estimation;Monitoring;Convex optimization;Generative adversarial networks (GAN);Load injection profile;Smart meters}, doi={10.1109/NAPS61145.2024.10741806}}
Comparative Analysis of Information Theoretic and Statistical Methods for Line Parameter Estimation. Sharma, A.; Varghese, A. C.; and Pal, A. 2024.
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@misc{sharma2024comparative, title={Comparative Analysis of Information Theoretic and Statistical Methods for Line Parameter Estimation}, author={Anushka Sharma and Antos Cheeramban Varghese and Anamitra Pal}, url = {https://arxiv.org/pdf/2404.16165}, year={2024}, eprint={2404.16165}, archivePrefix={arXiv}, primaryClass={eess.SP} }
High-Speed Voltage Control in Active Distribution Systems with Smart Inverter Coordination and Deep Reinforcement Learning. Golgol, M.; and Pal, A. 2024 IEEE PES General Meeting. 2024.
@article{golgol2023high, title={High-Speed Voltage Control in Active Distribution Systems with Smart Inverter Coordination and Deep Reinforcement Learning}, author={Golgol, Mohammad and Pal, Anamitra}, url = {https://arxiv.org/pdf/2311.13080v2}, journal={2024 IEEE PES General Meeting}, year={2024} }
Transmission Line Parameter Estimation Under Non-Gaussian Measurement Noise. Varghese, A. C.; Pal, A.; and Dasarathy, G. IEEE Transactions on Power Systems, 38(4): 3147-3162. 2023.
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@ARTICLE{9875997, author={Varghese, Antos Cheeramban and Pal, Anamitra and Dasarathy, Gautam}, journal={IEEE Transactions on Power Systems}, title={Transmission Line Parameter Estimation Under Non-Gaussian Measurement Noise}, year={2023}, volume={38}, number={4}, pages={3147-3162}, keywords={Transmission line measurements;Phasor measurement units;Noise measurement;Power transmission lines;Parameter estimation;Current measurement;Estimation;Expectation maximization;Gaussian mixture model;non-Gaussian noise;parameter estimation}, doi={10.1109/TPWRS.2022.3204232}}
PMU-Timescale Topology Identification of Sub-station Node-Breaker Models using Deep Learning. Azimian, B.; Pal, A.; Abu-Jaradeh, B.; Chen, L.; and Markham, P. In 2023 IEEE Power & Energy Society General Meeting (PESGM), pages 1–5, 2023. IEEE
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@inproceedings{azimian2023pmu, title={PMU-Timescale Topology Identification of Sub-station Node-Breaker Models using Deep Learning}, author={Azimian, Behrouz and Pal, Anamitra and Abu-Jaradeh, Backer and Chen, Lang and Markham, Penn}, booktitle={2023 IEEE Power \& Energy Society General Meeting (PESGM)}, url = {https://ieeexplore.ieee.org/document/10252994}, pages={1--5}, year={2023}, organization={IEEE} }
Time-Synchronized State Estimation Using Graph Neural Networks in Presence of Topology Changes. Moshtagh, S.; Sifat, A.; Azimian, B.; and Pal, A. In Proc. 55th Annual North American Power Symposium (NAPS), Asheville, NC, USA, October 2023.
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@inproceedings{moshtagh2023time, title={Time-Synchronized State Estimation Using Graph Neural Networks in Presence of Topology Changes}, author={Moshtagh, Shiva and Sifat, A.I. and Azimian, Behrouz and Pal, Anamitra}, url = {https://arxiv.org/pdf/2212.04592}, booktitle={Proc. 55th Annual North American Power Symposium (NAPS)}, year={2023}, address={Asheville, NC, USA}, month={October} }
Cross-Correlated Scenario Generation for Renewable-Rich Power Systems Using Implicit Generative Models. Dalal, D.; Bilal, M.; Shah, H.; Sifat, A. I.; Pal, A.; and Augustin, P. Energies, 16(4): 1636. 2023.
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@article{dalal2023cross, title={Cross-Correlated Scenario Generation for Renewable-Rich Power Systems Using Implicit Generative Models}, author={Dalal, Dhaval and Bilal, Muhammad and Shah, Hritik and Sifat, Anwarul Islam and Pal, Anamitra and Augustin, Philip}, journal={Energies}, volume={16}, number={4}, pages={1636}, year={2023}, publisher={MDPI}, url = {https://www.mdpi.com/1996-1073/16/4/1636} }
Data-Driven Flow and Injection Estimation in PMU-Unobservable Transmission Systems. Sahoo, S.; Sifat, A. I.; and Pal, A. In IEEE Power Energy Society General Meeting, 2023. IEEE
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@inproceedings{sahoo2022data, title={Data-Driven Flow and Injection Estimation in PMU-Unobservable Transmission Systems}, year = {2023}, author={Sahoo, Satyaprajna and Sifat, Anwarul Islam and Pal, Anamitra}, publisher = {IEEE}, booktitle = {IEEE Power Energy Society General Meeting}, url = {https://arxiv.org/pdf/2212.04560} }
Gain Scheduled Adaptive Control Scheme for Damping SSOs in PMSG-Integrated Power System Under High Wind Speed Variability. Wang, T.; Jin, M.; Jafarpisheh, B.; Pal, A.; and Wang, Z. Electric Power Components and Systems, 0(0): 1-14. 2022.
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@article{Wang_Gain_2022, author = {Tong Wang and Mingxin Jin and Babak Jafarpisheh and Anamitra Pal and Zengping Wang}, title = {Gain Scheduled Adaptive Control Scheme for Damping SSOs in PMSG-Integrated Power System Under High Wind Speed Variability}, journal = {Electric Power Components and Systems}, volume = {0}, number = {0}, pages = {1-14}, year = {2022}, publisher = {Taylor & Francis}, doi = {10.1080/15325008.2022.2049656}, URL = { https://doi.org/10.1080/15325008.2022.2049656 }, eprint = { https://doi.org/10.1080/15325008.2022.2049656 } , abstract = { AbstractA gain scheduled adaptive control scheme based on a polytopic linear parameter varying (LPV) system is proposed in this paper to damp sub-synchronous oscillations (SSOs) for power system integrated with permanent magnet synchronous generators (PMSGs) and operating under high wind speed variability. Firstly, the linearized state space model of the PMSG-integrated power system is established. Secondly, a polytopic LPV system is developed to account for the stochastic drift behavior and wind speed variability. Next, a gap metric-based nonlinearity measurement method is used for configuring the vertices of the polytope. The adaptive polytopic LPV controller is solved using linear matrix inequality and gain scheduling control theory, while mode identification based on a sliding window fast Fourier transform is employed for adaptively adjusting the polytopic LPV controller. Finally, the proposed polytopic LPV adaptive control scheme is compared with three other control techniques to demonstrate its effectiveness in suppressing SSOs. } }
AbstractA gain scheduled adaptive control scheme based on a polytopic linear parameter varying (LPV) system is proposed in this paper to damp sub-synchronous oscillations (SSOs) for power system integrated with permanent magnet synchronous generators (PMSGs) and operating under high wind speed variability. Firstly, the linearized state space model of the PMSG-integrated power system is established. Secondly, a polytopic LPV system is developed to account for the stochastic drift behavior and wind speed variability. Next, a gap metric-based nonlinearity measurement method is used for configuring the vertices of the polytope. The adaptive polytopic LPV controller is solved using linear matrix inequality and gain scheduling control theory, while mode identification based on a sliding window fast Fourier transform is employed for adaptively adjusting the polytopic LPV controller. Finally, the proposed polytopic LPV adaptive control scheme is compared with three other control techniques to demonstrate its effectiveness in suppressing SSOs.
Coordinated wide-area damping control using deep neural networks and reinforcement learning. Gupta, P.; Pal, A.; and Vittal, V. IEEE Transactions on Power Systems, 37(1): 365–376. Jan 2022.
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@Article{gupta_coordinated_wide_area_2021, journal = {IEEE Transactions on Power Systems}, title = {Coordinated wide-area damping control using deep neural networks and reinforcement learning}, url = {https://ieeexplore.ieee.org/document/9463673}, year = {2022}, month = {Jan}, pages = {365--376}, volume = {37}, number = {1}, author = {Gupta, Pooja and Pal, Anamitra and Vittal, Vijay}, doi = {10.1109/TPWRS.2021.3091940}, abstract = {This paper proposes the design of two coordinated wide-area damping controllers (CWADCs) for damping low frequency oscillations (LFOs), while accounting for the uncertainties present in the power system. The controllers based on Deep Neural Network (DNN) and Deep Reinforcement Learning (DRL), respectively, coordinate the operation of different local damping controls such as power system stabilizers (PSSs), static VAr compensators (SVCs), and supplementary damping controllers for DC lines (DC-SDCs). The DNN-CWADC learns to make control decisions using supervised learning; the training dataset consisting of polytopic controllers designed with the help of linear matrix inequality (LMI)-based mixed H2/H∞ optimization. The DRL-CWADC learns to adapt to the system uncertainties based on its continuous interaction with the power system environment by employing an advanced version of the state-of-the-art deep deterministic policy gradient (DDPG) algorithm referred to as \emph{bounded exploratory control}-based DDPG (BEC-DDPG). The studies performed on a 33 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system-embedded with different types of damping controls demonstrate the effectiveness of the proposed CWADCs.} }
This paper proposes the design of two coordinated wide-area damping controllers (CWADCs) for damping low frequency oscillations (LFOs), while accounting for the uncertainties present in the power system. The controllers based on Deep Neural Network (DNN) and Deep Reinforcement Learning (DRL), respectively, coordinate the operation of different local damping controls such as power system stabilizers (PSSs), static VAr compensators (SVCs), and supplementary damping controllers for DC lines (DC-SDCs). The DNN-CWADC learns to make control decisions using supervised learning; the training dataset consisting of polytopic controllers designed with the help of linear matrix inequality (LMI)-based mixed H2/H∞ optimization. The DRL-CWADC learns to adapt to the system uncertainties based on its continuous interaction with the power system environment by employing an advanced version of the state-of-the-art deep deterministic policy gradient (DDPG) algorithm referred to as \emphbounded exploratory control-based DDPG (BEC-DDPG). The studies performed on a 33 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system-embedded with different types of damping controls demonstrate the effectiveness of the proposed CWADCs.
Representative scenarios to capture renewable generation stochasticity and cross-correlations. Dalal, D.; Pal, A.; and Augustin, P. In IEEE Power Energy Society General Meeting, 2022. IEEE
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@inproceedings{dalal_representative_2022, title = {Representative scenarios to capture renewable generation stochasticity and cross-correlations}, year = {2022}, author = {Dalal, Dhaval and Pal, Anamitra and Augustin, Philip}, publisher = {IEEE}, booktitle = {IEEE Power Energy Society General Meeting}, url = {https://ieeexplore.ieee.org/document/9917243} }
State and Topology Estimation for Unobservable Distribution Systems using Deep Neural Networks. Azimian, B.; Biswas, R. S.; Pal, A.; Tong, L.; and Dasarathy, G. IEEE Transactions on Instrumentation and Measurements, abs/2104.07208. 2021.
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@article{Azimian_state_2022, author = {Behrouz Azimian and Reetam Sen Biswas and Anamitra Pal and Lang Tong and Gautam Dasarathy}, title = {State and Topology Estimation for Unobservable Distribution Systems using Deep Neural Networks}, journal = {IEEE Transactions on Instrumentation and Measurements}, volume = {abs/2104.07208}, year = {2021}, url = {https://ieeexplore.ieee.org/document/9758816}, eprinttype = {arXiv}, eprint = {2104.07208}, timestamp = {Mon, 19 Apr 2021 16:45:47 +0200}, biburl = {https://dblp.org/rec/journals/corr/abs-2104-07208.bib}, bibsource = {dblp computer science bibliography, https://dblp.org}}
Mitigation of saturated cut-sets during multiple outages to enhance power system security. Biswas, R. S.; Pal, A.; Werho, T.; and Vittal, V. IEEE Transactions on Power Systems, 36(6): 5734–5745. Nov 2021.
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@Article{biswas_mitigation_2021, title = {Mitigation of saturated cut-sets during multiple outages to enhance power system security}, year = {2021}, month = {Nov}, journal = {IEEE Transactions on Power Systems}, author = {Biswas, Reetam Sen and Pal, Anamitra and Werho, Trevor and Vittal, Vijay}, url = {https://ieeexplore.ieee.org/document/9420300}, abstract = {Ensuring reliable operation of large power systems subjected to multiple outages is a challenging task because of the combinatorial nature of the problem. Traditional approaches for security assessment are often limited by their scope and/or speed, resulting in missing of critical contingencies that could lead to cascading failures. This paper proposes a two-component methodology to enhance power system security. The first component combines an efficient algorithm to detect cut-set saturation (called the feasibility test (FT) algorithm) with real-time contingency analysis (RTCA) to create an integrated corrective action (iCA), whose goal is to secure the system against cut-set saturation as well as critical branch overloads. The second component only employs the results of the FT to create a relaxed corrective action (rCA) to secure the system against post-contingency cut-set saturation. The first component is more comprehensive, but the latter is computationally more efficient. The effectiveness of the two components is evaluated based upon the number of cascade triggering contingencies alleviated, and the computation time. The results obtained by analyzing different case-studies on the IEEE 118-bus and 2000-bus synthetic Texas systems indicate that the proposed two-component methodology successfully enhances the scope and speed of power system security assessment during multiple outages}, pages = {5734--5745}, volume = {36}, number = {6} }
Ensuring reliable operation of large power systems subjected to multiple outages is a challenging task because of the combinatorial nature of the problem. Traditional approaches for security assessment are often limited by their scope and/or speed, resulting in missing of critical contingencies that could lead to cascading failures. This paper proposes a two-component methodology to enhance power system security. The first component combines an efficient algorithm to detect cut-set saturation (called the feasibility test (FT) algorithm) with real-time contingency analysis (RTCA) to create an integrated corrective action (iCA), whose goal is to secure the system against cut-set saturation as well as critical branch overloads. The second component only employs the results of the FT to create a relaxed corrective action (rCA) to secure the system against post-contingency cut-set saturation. The first component is more comprehensive, but the latter is computationally more efficient. The effectiveness of the two components is evaluated based upon the number of cascade triggering contingencies alleviated, and the computation time. The results obtained by analyzing different case-studies on the IEEE 118-bus and 2000-bus synthetic Texas systems indicate that the proposed two-component methodology successfully enhances the scope and speed of power system security assessment during multiple outages
A robust algorithm for real-time phasor and frequency estimation under diverse system conditions. Jafarpisheh, B.; and Pal, A. Energies, 14(21): 1–20. Apr 2021.
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@Article{jafarpisheh_robust_2021, AUTHOR = {Jafarpisheh, Babak and Pal, Anamitra}, TITLE = {A robust algorithm for real-time phasor and frequency estimation under diverse system conditions}, JOURNAL = {Energies}, VOLUME = {14}, YEAR = {2021}, month = {Apr}, NUMBER = {21}, ARTICLE-NUMBER = {7112}, URL = {https://www.mdpi.com/1996-1073/14/21/7112}, ISSN = {1996-1073}, ABSTRACT = {This paper presents a comprehensive approach for performing phasor and frequency estimation from voltage and/or current signals of the modern power system. Undesirable components, such as decaying DC, if present in the input signal, are first attenuated using a complex-gain filter. The initial estimates of phasor and frequency are obtained next using the discrete Fourier transform and an improved estimation of signal parameters via rotational invariance technique, respectively. Finally, the accuracy of phasor and frequency estimates are increased based on the identified system condition. Simulations performed to evaluate the proposed approach confirm that it can do fast and accurate estimation of phasor and frequency under diverse operating conditions, making it ideal for wide-area monitoring, protection, and control applications in power systems.}, DOI = {10.3390/en14217112}, pages = {1--20} }
This paper presents a comprehensive approach for performing phasor and frequency estimation from voltage and/or current signals of the modern power system. Undesirable components, such as decaying DC, if present in the input signal, are first attenuated using a complex-gain filter. The initial estimates of phasor and frequency are obtained next using the discrete Fourier transform and an improved estimation of signal parameters via rotational invariance technique, respectively. Finally, the accuracy of phasor and frequency estimates are increased based on the identified system condition. Simulations performed to evaluate the proposed approach confirm that it can do fast and accurate estimation of phasor and frequency under diverse operating conditions, making it ideal for wide-area monitoring, protection, and control applications in power systems.
Ensuring reliable operation of electricity grid by placement of FACTS devices for developing countries. Khan, A. N.; Imran, K.; Nadeem, M.; Pal, A.; Khattak, A.; Ullah, K.; Younas, M. W.; and Younis, M. S. Energies, 14(8): 1–21. April 2021.
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@article{khan_ensuring_2021, title = {Ensuring reliable operation of electricity grid by placement of FACTS devices for developing countries}, volume = {14}, url = {https://www.mdpi.com/1996-1073/14/8/2283}, abstract = {Flexible AC Transmission Systems (FACTS) are essential devices used for the efficient performance of modern power systems and many developing countries lack these devices. Due to the non-existence of these advanced technologies, the national grid remains weak and vulnerable to power stability issues that can jeopardize system stability. This study proposes novel research to solve issues of an evolving national grid through the installation of FACTS devices. FACTS devices play a crucial role in minimizing active power losses while managing reactive power flows to keep the voltages within their respective limits. Due to the high costs of FACTS, optimization must be done to discover optimal locations as well as ratings of these devices. However, due to the nonlinearity, it is a challenging task to find the optimal locations and appropriate sizes of these devices. Shunt VARs Compensators (SVCs) and Thyristor-Controlled Series Compensators (TCSCs) are the two FACTS devices considered for the study. Optimal locations for SVCs and TCSCs are determined by Voltage Collapse Proximity Index (VCPI) and Line Stability Index (Lmn), respectively. Particle Swarm Optimization (PSO) is employed to find the ideal rating for FACTS devices to minimize the system operating cost (cost due to active power loss and capital cost of FACTS devices). This technique is applied to IEEE (14 and 30) bus systems. Moreover, reliable operation of the electricity grid through the placement of FACTS for developing countries has also been analysed; Pakistan being a developing country has been selected as a case study. The planning problem has been solved for the present as well as for the forecasted power system. Consequently, in the current national network, 6.21\% and 6.71\% reduction in active and reactive power losses have been observed, respectively. Moreover, voltage profiles have been improved significantly. A detailed financial analysis covering the calculation of Operation Cost (OC) of the national grid before and after the placement of FACTS devices is carried out.}, number = {8}, journal = {Energies}, pages = {1--21}, author = {Khan, Atif Naveed and Imran, Kashif and Nadeem, Muhammad and Pal, Anamitra and Khattak, Abraiz and Ullah, Kafait and Younas, Muhammad Waseem and Younis, Muhammad Shahzad}, month = apr, year = {2021}, keywords = {Flexible AC Transmission System (FACTS), Line Stability Index (Lmn), Particle Swarm Optimization (PSO), Voltage Collapse Proximity Index (VCPI)}, file = {Snapshot:/Users/jairoramirez 1/Zotero/storage/Z96SH8BP/2283.html:text/html;Full Text PDF:/Users/jairoramirez 1/Zotero/storage/ZUITAFYH/Khan et al. - 2021 - Ensuring Reliable Operation of Electricity Grid by.pdf:application/pdf}, }
Flexible AC Transmission Systems (FACTS) are essential devices used for the efficient performance of modern power systems and many developing countries lack these devices. Due to the non-existence of these advanced technologies, the national grid remains weak and vulnerable to power stability issues that can jeopardize system stability. This study proposes novel research to solve issues of an evolving national grid through the installation of FACTS devices. FACTS devices play a crucial role in minimizing active power losses while managing reactive power flows to keep the voltages within their respective limits. Due to the high costs of FACTS, optimization must be done to discover optimal locations as well as ratings of these devices. However, due to the nonlinearity, it is a challenging task to find the optimal locations and appropriate sizes of these devices. Shunt VARs Compensators (SVCs) and Thyristor-Controlled Series Compensators (TCSCs) are the two FACTS devices considered for the study. Optimal locations for SVCs and TCSCs are determined by Voltage Collapse Proximity Index (VCPI) and Line Stability Index (Lmn), respectively. Particle Swarm Optimization (PSO) is employed to find the ideal rating for FACTS devices to minimize the system operating cost (cost due to active power loss and capital cost of FACTS devices). This technique is applied to IEEE (14 and 30) bus systems. Moreover, reliable operation of the electricity grid through the placement of FACTS for developing countries has also been analysed; Pakistan being a developing country has been selected as a case study. The planning problem has been solved for the present as well as for the forecasted power system. Consequently, in the current national network, 6.21% and 6.71% reduction in active and reactive power losses have been observed, respectively. Moreover, voltage profiles have been improved significantly. A detailed financial analysis covering the calculation of Operation Cost (OC) of the national grid before and after the placement of FACTS devices is carried out.
A graph theoretic approach to power system vulnerability identification. Biswas, R. S.; Pal, A.; Werho, T.; and Vittal, V. IEEE Transactions on Power Systems, 36(2): 923–935. March 2021.
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@article{biswas_graph_2021, title = {A graph theoretic approach to power system vulnerability identification}, volume = {36}, url = {https://ieeexplore.ieee.org/abstract/document/9144487}, abstract = {During major power system disturbances, when multiple component outages occur in rapid succession, it becomes crucial to quickly identify the transmission interconnections that have limited power transfer capability. Understanding the impact of an outage on these critical interconnections (called saturated cut-sets) is important for enhancing situational awareness and taking correct actions. This paper proposes a new graph theoretic approach for analyzing whether a contingency will create a saturated cut-set in a meshed power network. A novel feature of the proposed algorithm is that it lowers the solution time significantly making the approach viable for real-time operations. It also indicates the minimum amount by which the power transfer through the critical interconnections should be reduced so that post-contingency saturation does not occur. Robustness of the proposed algorithm for enhanced situational awareness is demonstrated using the IEEE-118 bus system as well as a 17,000+ bus model of the Western Interconnection (WI). Comparisons made with different approaches for power system vulnerability assessment prove the utility of the proposed scheme for aiding power system operations during extreme exigencies.}, number = {2}, journal = {IEEE Transactions on Power Systems}, author = {Biswas, Reetam Sen and Pal, Anamitra and Werho, Trevor and Vittal, Vijay}, month = mar, year = {2021}, keywords = {Flow graphs, Graph theory, Load flow, network flow, power system disturbances, Power system faults, Power system stability, power system vulnerability, Power transmission lines, Real-time systems, saturated cut-set}, pages = {923--935}, }
During major power system disturbances, when multiple component outages occur in rapid succession, it becomes crucial to quickly identify the transmission interconnections that have limited power transfer capability. Understanding the impact of an outage on these critical interconnections (called saturated cut-sets) is important for enhancing situational awareness and taking correct actions. This paper proposes a new graph theoretic approach for analyzing whether a contingency will create a saturated cut-set in a meshed power network. A novel feature of the proposed algorithm is that it lowers the solution time significantly making the approach viable for real-time operations. It also indicates the minimum amount by which the power transfer through the critical interconnections should be reduced so that post-contingency saturation does not occur. Robustness of the proposed algorithm for enhanced situational awareness is demonstrated using the IEEE-118 bus system as well as a 17,000+ bus model of the Western Interconnection (WI). Comparisons made with different approaches for power system vulnerability assessment prove the utility of the proposed scheme for aiding power system operations during extreme exigencies.
Coordinated wide-area control of multiple controllers in a power system embedded with HVDC lines. Gupta, P.; Pal, A.; and Vittal, V. IEEE Transactions on Power Systems, 36(1): 648–658. January 2021.
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@article{gupta_coordinated_2021, title = {Coordinated wide-area control of multiple controllers in a power system embedded with HVDC lines}, volume = {36}, url = {https://ieeexplore.ieee.org/abstract/document/9166750}, abstract = {This paper develops a coordinated wide-area control of power system stabilizers (PSSs), static VAr compensators (SVCs), and supplementary damping controllers (SDCs) for damping low frequency oscillations (LFOs) in a power system embedded with multiple high voltage DC (HVDC) lines. The improved damping is achieved by designing a coordinated wide-area damping controller (CWADC) that employs partial state feedback. The design methodology uses a linear matrix inequality (LMI)-based mixed H2/H∞ robust control for multiple operating scenarios. To reduce the high computational burden, an enhanced version of selective modal analysis (SMA) is employed that not only reduces the number of required wide-area feedback signals, but also identifies alternate feedback signals, in case of failure of the primary signals. Additionally, the impact of delays on the performance of the control design is investigated. The studies are performed on a 29 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system-embedded with three HVDC lines and two wind farms.}, number = {1}, journal = {IEEE Transactions on Power Systems}, author = {Gupta, Pooja and Pal, Anamitra and Vittal, Vijay}, month = jan, year = {2021}, keywords = {Coordinated wide-area damping controller (CWADC), Damping, Frequency control, high voltage direct current (HVDC), HVDC transmission, linear matrix inequality (LMI), Oscillators, partial state feedback, phasor measurement unit (PMU), Phasor measurement units, polytopic control, Power system stability, selective modal analysis (SMA), State feedback}, pages = {648--658}, }
This paper develops a coordinated wide-area control of power system stabilizers (PSSs), static VAr compensators (SVCs), and supplementary damping controllers (SDCs) for damping low frequency oscillations (LFOs) in a power system embedded with multiple high voltage DC (HVDC) lines. The improved damping is achieved by designing a coordinated wide-area damping controller (CWADC) that employs partial state feedback. The design methodology uses a linear matrix inequality (LMI)-based mixed H2/H∞ robust control for multiple operating scenarios. To reduce the high computational burden, an enhanced version of selective modal analysis (SMA) is employed that not only reduces the number of required wide-area feedback signals, but also identifies alternate feedback signals, in case of failure of the primary signals. Additionally, the impact of delays on the performance of the control design is investigated. The studies are performed on a 29 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system-embedded with three HVDC lines and two wind farms.
Optimal cost network design for bounded delay data transfer from PMU to control center. Sen, A.; Roy, S.; Basu, K.; Adeniye, S.; Choudhuri, S.; and Pal, A. In IEEE GLOBECOM, pages 1–6, Madrid, Spain, December 2021. IEEE
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@inproceedings{sen_optimal_2021, address = {Madrid, Spain}, title = {Optimal cost network design for bounded delay data transfer from PMU to control center}, url = {https://ieeexplore.ieee.org/document/9685580}, year = {2021}, month = {December}, publisher = {IEEE}, booktitle = {IEEE GLOBECOM}, author = {Sen, Arunabha and Roy, Sohini and Basu, Kaustav and Adeniye, Suli and Choudhuri, Sandipan and Pal, Anamitra}, pages = {1--6}, }
GPS spoofing attacks on phasor measurement units: practical feasibility and countermeasures. Saadedeen, F.; and Pal, A. In IEEE North American Power Symposium (NAPS), pages 1–6, College Station, TX, Jul 2021.
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@inproceedings{saadedeen_gps_2021, title={GPS spoofing attacks on phasor measurement units: practical feasibility and countermeasures}, author={Fakhri Saadedeen and Anamitra Pal}, year={2021}, month = {Jul}, eprint={2110.03447}, archivePrefix={arXiv}, primaryClass={cs.CR}, link = {https://ieeexplore.ieee.org/document/9654472}, abstract = {Prior research has demonstrated that global positioning system (GPS) spoofing attacks on phasor measurement units (PMUs) can cripple power system operation. This paper provides an experimental evidence of the feasibility of such an attack using commonly available digital radios known as software defined radio (SDR). It also introduces a novel countermeasure against such attacks using GPS signal redundancy and low power long range (LoRa) spread spectrum modulation technique. The proposed approach checks the integrity of the GPS signal at remote locations and compares the data with the PMU’s current output. This countermeasure is a ready-to-deploy system that can provide an instant solution to the GPS spoofing detection problem for PMUs.}, booktitle = {IEEE North American Power Symposium (NAPS)}, address = {College Station, TX}, pages = {1--6} }
Prior research has demonstrated that global positioning system (GPS) spoofing attacks on phasor measurement units (PMUs) can cripple power system operation. This paper provides an experimental evidence of the feasibility of such an attack using commonly available digital radios known as software defined radio (SDR). It also introduces a novel countermeasure against such attacks using GPS signal redundancy and low power long range (LoRa) spread spectrum modulation technique. The proposed approach checks the integrity of the GPS signal at remote locations and compares the data with the PMU’s current output. This countermeasure is a ready-to-deploy system that can provide an instant solution to the GPS spoofing detection problem for PMUs.
Time synchronized distribution system state estimation for incompletely observed systems using deep learning and realistic measurement noise. Azimian, B.; Biswas, R. S.; Pal, A.; and Tong, L. In 2021 IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Washington DC, USA, July 2021.
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@INPROCEEDINGS{azimian_time_2021, author={Azimian, B. and Biswas, R. Sen and Pal, A. and Tong, Lang}, booktitle={2021 IEEE Power Energy Society General Meeting (PESGM)}, title={Time synchronized distribution system state estimation for incompletely observed systems using deep learning and realistic measurement noise}, year={2021}, url = {https://ieeexplore.ieee.org/document/9637858}, volume={}, number={}, pages={1--5}, abstract={Time-synchronized state estimation is a challenge for distribution systems because of limited real-time observability. This paper addresses this challenge by formulating a deep learning (DL)-based approach to perform unbalanced three-phase distribution system state estimation (DSSE). Initially, a data-driven approach for judicious measurement selection to facilitate reliable state estimation is provided. Then, a deep neural network (DNN) is trained to perform DSSE for systems that are incompletely observed by synchrophasor measurement devices (SMDs). Robustness of the proposed methodology is demonstrated by considering realistic measurement error models for SMDs. A comparative study of the DNN-based DSSE with classical linear state estimation indicates that the DL-based approach gives better accuracy with a significantly smaller number of SMDs.}, keywords={}, doi={10.1109/PESGM46819.2021.9637858}, ISSN={1944-9933}, month={July}, address = {Washington DC, USA} }
Time-synchronized state estimation is a challenge for distribution systems because of limited real-time observability. This paper addresses this challenge by formulating a deep learning (DL)-based approach to perform unbalanced three-phase distribution system state estimation (DSSE). Initially, a data-driven approach for judicious measurement selection to facilitate reliable state estimation is provided. Then, a deep neural network (DNN) is trained to perform DSSE for systems that are incompletely observed by synchrophasor measurement devices (SMDs). Robustness of the proposed methodology is demonstrated by considering realistic measurement error models for SMDs. A comparative study of the DNN-based DSSE with classical linear state estimation indicates that the DL-based approach gives better accuracy with a significantly smaller number of SMDs.
An inductively powered line-mounted time-synchronized micro point-on-wave recorder. Patterson, J.; and Pal, A. In 2021 IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Washington DC, USA, July 2021.
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@INPROCEEDINGS{patterson_inductively_2021, author={Patterson, John and Pal, Anamitra}, booktitle={2021 IEEE Power Energy Society General Meeting (PESGM)}, title={An inductively powered line-mounted time-synchronized micro point-on-wave recorder}, year={2021}, url = {https://ieeexplore.ieee.org/document/9637898}, volume={}, number={}, pages={1--5}, abstract={The distribution system is an integral component of the electric power system, but not much is known about how it behaves in real-time. To address this knowledge gap, a low-cost, time-synchronized, micro point-on-wave (PoW) recorder is designed, built, and characterized in this paper. The inductively powered recorder operates wirelessly by using the current flowing through a typical distribution conductor. The recorder is designed to be small, lightweight, and is intended to be installed directly on the power line. To validate the performance of this recorder, tests of measurement accuracy, electric current requirements, and susceptibility to electromagnetic interference from both steady-state and arc-induced sources are performed. The results indicate that the proposed recorder satisfies both the technical as well as the economical constraints required for bulk deployment in an actual distribution network.}, keywords={}, doi={10.1109/PESGM46819.2021.9637898}, ISSN={1944-9933}, month={July}, address = {Washington DC, USA} }
The distribution system is an integral component of the electric power system, but not much is known about how it behaves in real-time. To address this knowledge gap, a low-cost, time-synchronized, micro point-on-wave (PoW) recorder is designed, built, and characterized in this paper. The inductively powered recorder operates wirelessly by using the current flowing through a typical distribution conductor. The recorder is designed to be small, lightweight, and is intended to be installed directly on the power line. To validate the performance of this recorder, tests of measurement accuracy, electric current requirements, and susceptibility to electromagnetic interference from both steady-state and arc-induced sources are performed. The results indicate that the proposed recorder satisfies both the technical as well as the economical constraints required for bulk deployment in an actual distribution network.
Statistical characterization of random errors present in synchrophasor measurements. Salls, D.; Torres, J. R.; Antos; Varghese, C.; Patterson, J.; and Pal, A. In 2021 IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Washington DC, USA, July 2021.
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@INPROCEEDINGS{salls_statistical_2021, author={Salls, Demetra and Torres, Jairo Ramírez and Antos and Varghese, Cheeramban and Patterson, John and Pal, Anamitra}, booktitle={2021 IEEE Power Energy Society General Meeting (PESGM)}, title={Statistical characterization of random errors present in synchrophasor measurements}, url = {https://ieeexplore.ieee.org/document/9638135}, year={2021}, volume={}, number={}, pages={1--5}, abstract={The statistical characterization of the measurement errors of a phasor measurement unit (PMU) is currently receiving considerable interest in the power systems community. This paper focuses on the characteristics of the errors in magnitude and angle measurements introduced only by the PMU device (called random errors in this paper), during ambient conditions, using a high-precision calibrator. The experimental results indicate that the random errors follow a non-Gaussian distribution. They also show that the M-class and P-class PMUs have distinct error characteristics. The results of this analysis will help researchers design algorithms that account for the non-Gaussian nature of the errors in synchrophasor measurements, thereby improving the practical utility of the said-algorithms in addition to building on precedence for using high-precision calibrators to perform accurate error tests.}, keywords={}, doi={10.1109/PESGM46819.2021.9638135}, ISSN={1944-9933}, month={July}, address = {Washington DC, USA} }
The statistical characterization of the measurement errors of a phasor measurement unit (PMU) is currently receiving considerable interest in the power systems community. This paper focuses on the characteristics of the errors in magnitude and angle measurements introduced only by the PMU device (called random errors in this paper), during ambient conditions, using a high-precision calibrator. The experimental results indicate that the random errors follow a non-Gaussian distribution. They also show that the M-class and P-class PMUs have distinct error characteristics. The results of this analysis will help researchers design algorithms that account for the non-Gaussian nature of the errors in synchrophasor measurements, thereby improving the practical utility of the said-algorithms in addition to building on precedence for using high-precision calibrators to perform accurate error tests.
Identification of utility-scale renewable energy penetration threshold in a dynamic setting. Albhrani, H.; Biswas, R. S.; and Pal, A. In Proc. IEEE North American Power Symposium (NAPS), Tempe, AZ, April 2021.
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@inproceedings{albhrani_identification_2021, address = {Tempe, AZ.}, title = {Identification of utility-scale renewable energy penetration threshold in a dynamic setting}, url = {https://ieeexplore.ieee.org/document/9449753}, abstract = {Integration of renewable energy resources with the electric grid is necessary for a sustainable energy future. However, increased penetration of inverter based resources (IBRs) reduce grid inertia, which might then compromise power system reliability. Therefore, power utilities are often interested in identifying the maximum IBR penetration limit for their system. The proposed research presents a methodology to identify the IBR penetration threshold beyond which voltage, frequency, and tie-line limits will be exceeded. The sensitivity of the IBR penetration threshold to momentary cessation due to low voltages, transmission versus distribution connected solar generation, and stalling of induction motors are also analyzed. Dynamic simulation studies conducted on a 24,000-bus model of the Western Interconnection (WI) demonstrate the practicality of the proposed approach.}, booktitle = {Proc. IEEE North American Power Symposium (NAPS)}, author = {Albhrani, Hashem and Biswas, Reetam Sen and Pal, Anamitra}, month = apr, year = {2021}, keywords = {Electrical Engineering and Systems Science - Systems and Control}, address = {Tempe, AZ} }
Integration of renewable energy resources with the electric grid is necessary for a sustainable energy future. However, increased penetration of inverter based resources (IBRs) reduce grid inertia, which might then compromise power system reliability. Therefore, power utilities are often interested in identifying the maximum IBR penetration limit for their system. The proposed research presents a methodology to identify the IBR penetration threshold beyond which voltage, frequency, and tie-line limits will be exceeded. The sensitivity of the IBR penetration threshold to momentary cessation due to low voltages, transmission versus distribution connected solar generation, and stalling of induction motors are also analyzed. Dynamic simulation studies conducted on a 24,000-bus model of the Western Interconnection (WI) demonstrate the practicality of the proposed approach.
Optimal placement of electric vehicle charging stations in the active distribution network. Zeb, M. Z.; Imran, K.; Khattak, A.; Janjua, A. K.; Pal, A.; Nadeem, M.; Zhang, J.; and Khan, S. IEEE Access, 8(1): 68124–68134. December 2020.
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@article{zeb_optimal_2020, title = {Optimal placement of electric vehicle charging stations in the active distribution network}, volume = {8}, url = {https://ieeexplore.ieee.org/abstract/document/9050479}, abstract = {Electrification of the transportation sector can play a vital role in reshaping smart cities. With an increasing number of electric vehicles (EVs) on the road, deployment of well-planned and efficient charging infrastructure is highly desirable. Unlike level 1 and level 2 charging stations, level 3 chargers are super-fast in charging EVs. However, their installation at every possible site is not techno-economically justifiable because level 3 chargers may cause violation of critical system parameters due to their high power consumption. In this paper, we demonstrate an optimized combination of all three types of EV chargers for efficiently managing the EV load while minimizing installation cost, losses, and distribution transformer loading. Effects of photovoltaic (PV) generation are also incorporated in the analysis. Due to the uncertain nature of vehicle users, EV load is modeled as a stochastic process. Particle swarm optimization (PSO) is used to solve the constrained nonlinear stochastic problem. MATLAB and OpenDSS are used to simulate the model. The proposed idea is validated on the real distribution system of the National University of Sciences and Technology (NUST) Pakistan. Results show that an optimized combination of chargers placed at judicious locations can greatly reduce cost from \$3.55 million to \$1.99 million, daily losses from 787kWh to 286kWh and distribution transformer congestion from 58\% to 22\% when compared to scenario of optimized placement of level 3 chargers for 20\% penetration level in commercial feeders. In residential feeder, these statistics are improved from \$2.52 to \$0.81 million, from 2167kWh to 398kWh and from 106\% to 14\%, respectively. It is also realized that the integration of PV improves voltage profile and reduces the negative impact of EV load. Our optimization model can work for commercial areas such as offices, university campuses, and industries as well as residential colonies.}, number = {1}, journal = {IEEE Access}, author = {Zeb, Muhammad Zulqarnain and Imran, Kashif and Khattak, Abraiz and Janjua, Abdul Kashif and Pal, Anamitra and Nadeem, Muhammad and Zhang, Jiangfeng and Khan, Sohail}, month = dec, year = {2020}, keywords = {Charging stations, Charging stations placement, distribution system, Electric vehicle charging, electric vehicles (EVs), Load modeling, Mathematical model, optimization, Photovoltaic systems, Planning}, pages = {68124--68134}, }
Electrification of the transportation sector can play a vital role in reshaping smart cities. With an increasing number of electric vehicles (EVs) on the road, deployment of well-planned and efficient charging infrastructure is highly desirable. Unlike level 1 and level 2 charging stations, level 3 chargers are super-fast in charging EVs. However, their installation at every possible site is not techno-economically justifiable because level 3 chargers may cause violation of critical system parameters due to their high power consumption. In this paper, we demonstrate an optimized combination of all three types of EV chargers for efficiently managing the EV load while minimizing installation cost, losses, and distribution transformer loading. Effects of photovoltaic (PV) generation are also incorporated in the analysis. Due to the uncertain nature of vehicle users, EV load is modeled as a stochastic process. Particle swarm optimization (PSO) is used to solve the constrained nonlinear stochastic problem. MATLAB and OpenDSS are used to simulate the model. The proposed idea is validated on the real distribution system of the National University of Sciences and Technology (NUST) Pakistan. Results show that an optimized combination of chargers placed at judicious locations can greatly reduce cost from 3.55millionto1.99 million, daily losses from 787kWh to 286kWh and distribution transformer congestion from 58% to 22% when compared to scenario of optimized placement of level 3 chargers for 20% penetration level in commercial feeders. In residential feeder, these statistics are improved from 2.52to0.81 million, from 2167kWh to 398kWh and from 106% to 14%, respectively. It is also realized that the integration of PV improves voltage profile and reduces the negative impact of EV load. Our optimization model can work for commercial areas such as offices, university campuses, and industries as well as residential colonies.
Bilateral negotiations for electricity market by adaptive agent-tracking strategy. Imran, K.; Zhang, J.; Pal, A.; Khattak, A.; Ullah, K.; and Baig, S. M. Electric Power Systems Research, 186: 1–12. September 2020.
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@article{imran_bilateral_2020, title = {Bilateral negotiations for electricity market by adaptive agent-tracking strategy}, volume = {186}, url = {https://www.sciencedirect.com/science/article/pii/S0378779620301966}, abstract = {Bilateral transactions hedge both sides against uncertain price and volume risks of day-ahead auction and make up major portions of trading in electricity markets. Peer-to-peer bilateral transactions avoid broker fees but involve challenges of balancing between cooperative and competitive strategies for multi-round negotiations. To solve these challenges, this paper develops novel utility-based and adaptive agent-tracking strategies for bilateral negotiations. Relying on bilateral transaction volume and utility curves determined over a price range during unilateral pre-negotiation, utility-based strategies are developed for generation company (GenCo) agent (load serving entity (LSE) agent) to offer (bid) volumes and prices during multi-round bilateral negotiations. GenCo agent is also equipped with a new adaptive agent-tracking strategy that estimates reservation price of each LSE agent by Bayesian learning and updates the estimates in each round. The adaptive agent-tracking strategy facilitates cooperative yet competitive responses. Integration of new bilateral negotiation strategies with existing day-ahead auction in a renowned agent-based platform also enables combined simulation of the two market types. The case study demonstrates that the adaptive agent-tracking strategy empowers GenCoagents to swing bilateral negotiation results in their favor and yield 7\% more payoff than the utility-based strategy, while achieving 100\% improvement in frequency of failure of negotiation.}, journal = {Electric Power Systems Research}, author = {Imran, Kashif and Zhang, Jiangfeng and Pal, Anamitra and Khattak, Abraiz and Ullah, Kafait and Baig, Sherjeel Mahmood}, month = sep, year = {2020}, keywords = {Bilateral negotiations Day-ahead markets Peer-to-peer bilateral transactions Machine learning Heuristic methods Adaptive agents Agent-based models}, pages = {1--12}, }
Bilateral transactions hedge both sides against uncertain price and volume risks of day-ahead auction and make up major portions of trading in electricity markets. Peer-to-peer bilateral transactions avoid broker fees but involve challenges of balancing between cooperative and competitive strategies for multi-round negotiations. To solve these challenges, this paper develops novel utility-based and adaptive agent-tracking strategies for bilateral negotiations. Relying on bilateral transaction volume and utility curves determined over a price range during unilateral pre-negotiation, utility-based strategies are developed for generation company (GenCo) agent (load serving entity (LSE) agent) to offer (bid) volumes and prices during multi-round bilateral negotiations. GenCo agent is also equipped with a new adaptive agent-tracking strategy that estimates reservation price of each LSE agent by Bayesian learning and updates the estimates in each round. The adaptive agent-tracking strategy facilitates cooperative yet competitive responses. Integration of new bilateral negotiation strategies with existing day-ahead auction in a renowned agent-based platform also enables combined simulation of the two market types. The case study demonstrates that the adaptive agent-tracking strategy empowers GenCoagents to swing bilateral negotiation results in their favor and yield 7% more payoff than the utility-based strategy, while achieving 100% improvement in frequency of failure of negotiation.
A fixed-flexible BESS allocation scheme for transmission networks considering uncertainties. Padhee, M.; Pal, A.; Mishra, C.; and Vance, K. A. IEEE Transactions on Sustainable Energy, 11(3): 1883–1897. July 2020.
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@article{padhee_fixed-flexible_2020, title = {A fixed-flexible BESS allocation scheme for transmission networks considering uncertainties}, volume = {11}, url = {https://ieeexplore.ieee.org/abstract/document/8861411}, abstract = {Battery energy storage systems (BESSs) can play a key role in mitigating the intermittency and uncertainty associated with adding large amounts of renewable energy to the bulk power system (BPS). Two BESS technologies that have gained prominence in this regard are Lithium-ion (LI) BESS and Vanadium redox flow (VRF) BESS. This paper proposes a fixed-flexible BESS allocation scheme that exploits the complementary characteristics of LI and VRF BESSs to attain optimal techno-economic benefits in a wind-integrated BPS. Studies carried out on relatively large transmission networks demonstrate that benefits such as reduction in system operation cost, wind spillage, voltage fluctuations, and discounted payback period, can be realized by using the proposed scheme.}, number = {3}, journal = {IEEE Transactions on Sustainable Energy}, author = {Padhee, Malhar and Pal, Anamitra and Mishra, Chetan and Vance, Katelynn A.}, month = jul, year = {2020}, keywords = {Bivariate piecewise linearization (BPL), fixed-flexible BESS, Indexes, Investment, Load modeling, Maintenance engineering, mixed integer linear program (MILP), mixture model, Reactive power, Resource management, Vanadium redox flow (VRF), wind energy, Wind power generation}, pages = {1883--1897}, }
Battery energy storage systems (BESSs) can play a key role in mitigating the intermittency and uncertainty associated with adding large amounts of renewable energy to the bulk power system (BPS). Two BESS technologies that have gained prominence in this regard are Lithium-ion (LI) BESS and Vanadium redox flow (VRF) BESS. This paper proposes a fixed-flexible BESS allocation scheme that exploits the complementary characteristics of LI and VRF BESSs to attain optimal techno-economic benefits in a wind-integrated BPS. Studies carried out on relatively large transmission networks demonstrate that benefits such as reduction in system operation cost, wind spillage, voltage fluctuations, and discounted payback period, can be realized by using the proposed scheme.
Matchmaking model for bilateral trading decisions of load serving entity. Imran, K.; Ullah, K.; Khattak, A.; Zhang, J.; Pal, A.; Rafique, M. N.; and Baig, S. M. Electric Power Systems Research, 183: 1–11. June 2020.
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@article{imran_matchmaking_2020, title = {Matchmaking model for bilateral trading decisions of load serving entity}, volume = {183}, url = {https://www.sciencedirect.com/science/article/pii/S0378779620300870}, abstract = {Matchmaking and bilateral negotiations are two distinct phases of practical market participants’ decision making for bilateral transactions. Agent-based models are naturally suitable for electricity markets in general and bilateral transactions in particular. This paper's contribution includes development of a novel matchmaking model that generates forward contracting power and utility curves. The matchmaking model enables a load serving entity agent to undertake its own matchmaking, to find optimal trading allocations over a range of prices, before engaging in bilateral negotiations with generation company agents. Open-source agent-based simulation platform allows combined simulation of bilateral transactions and day-ahead auction. In this research paper, matchmaking is achieved by direct-search without any organized bulletin board, broker, or matchmaker. Instead of random matchmaking, portfolio optimization based matchmaking systematically explores available electricity trading options throughout the market: local and non-local bilateral trades as well as day-ahead auctions. The matchmaking algorithm is unique because it scans all trading options over the entire range of negotiable prices. Depending on private profit-seeking goals, risk-aversion preferences and market price statistics, each load serving entity agent individually finds its matchmaking results. A set of case studies demonstrates how matchmaking model depends on transmission rights and performs for different risk aversion factors.}, journal = {Electric Power Systems Research}, author = {Imran, Kashif and Ullah, Kafait and Khattak, Abraiz and Zhang, Jiangfeng and Pal, Anamitra and Rafique, Muhammad Nauman and Baig, Sherjeel Mahmood}, month = jun, year = {2020}, keywords = {Bilateral negotiations, Day-ahead markets, Direct-search bilateral trade, Matchmaking, Portfolio optimization}, pages = {1--11}, }
Matchmaking and bilateral negotiations are two distinct phases of practical market participants’ decision making for bilateral transactions. Agent-based models are naturally suitable for electricity markets in general and bilateral transactions in particular. This paper's contribution includes development of a novel matchmaking model that generates forward contracting power and utility curves. The matchmaking model enables a load serving entity agent to undertake its own matchmaking, to find optimal trading allocations over a range of prices, before engaging in bilateral negotiations with generation company agents. Open-source agent-based simulation platform allows combined simulation of bilateral transactions and day-ahead auction. In this research paper, matchmaking is achieved by direct-search without any organized bulletin board, broker, or matchmaker. Instead of random matchmaking, portfolio optimization based matchmaking systematically explores available electricity trading options throughout the market: local and non-local bilateral trades as well as day-ahead auctions. The matchmaking algorithm is unique because it scans all trading options over the entire range of negotiable prices. Depending on private profit-seeking goals, risk-aversion preferences and market price statistics, each load serving entity agent individually finds its matchmaking results. A set of case studies demonstrates how matchmaking model depends on transmission rights and performs for different risk aversion factors.
Robust, coordinated control of sub-synchronous oscillation in wind-integrated power system. Wang, T.; Yang, J.; Padhee, M.; Bi, J.; Pal, A.; and Wang, Z. IET Renewable Power Generation, 14(6): 1031–1043. April 2020.
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@article{wang_robust_2020, title = {Robust, coordinated control of sub-synchronous oscillation in wind-integrated power system}, volume = {14}, url = {https://digital-library.theiet.org/content/journals/10.1049/iet-rpg.2019.0410}, abstract = {This study presents a robust, coordinated control methodology for damping sub-synchronous oscillations (SSOs) while considering power output variations from multiple wind farms. The proposed damping control strategy utilises the mixed H 2/H ∞ control with regional pole placement to suppress the oscillations. For ensuring applicability over a wider operating range, the convex polytopic theory is utilised by using different operating points as the vertices of a convex polytope. The centralised, coordinated controller for damping SSOs is designed using linear matrix inequalities. Furthermore, unmeasurable state variables, if present, are represented by corresponding output variables. The damping signal is implemented as active power and reactive power modulation of the rotor-side converter of the doubly fed induction generators. A 4-machine, 2-area system and a 39-machine New England system are used to demonstrate the performance of the proposed control. The simulation results show that the polytopic controller can not only provide requisite damping to the SSO modes of interest, but also has good control performance when the wind power outputs change over a wide range.}, number = {6}, journal = {IET Renewable Power Generation}, author = {Wang, Tong and Yang, Jing and Padhee, Malhar and Bi, Jingtian and Pal, Anamitra and Wang, Zengping}, month = Apr, year = {2020}, pages = {1031--1043}, }
This study presents a robust, coordinated control methodology for damping sub-synchronous oscillations (SSOs) while considering power output variations from multiple wind farms. The proposed damping control strategy utilises the mixed H 2/H ∞ control with regional pole placement to suppress the oscillations. For ensuring applicability over a wider operating range, the convex polytopic theory is utilised by using different operating points as the vertices of a convex polytope. The centralised, coordinated controller for damping SSOs is designed using linear matrix inequalities. Furthermore, unmeasurable state variables, if present, are represented by corresponding output variables. The damping signal is implemented as active power and reactive power modulation of the rotor-side converter of the doubly fed induction generators. A 4-machine, 2-area system and a 39-machine New England system are used to demonstrate the performance of the proposed control. The simulation results show that the polytopic controller can not only provide requisite damping to the SSO modes of interest, but also has good control performance when the wind power outputs change over a wide range.
Identifying unique power system signatures for determining vulnerability of critical power system assets. Padhee, M.; Biswas, R. S.; Pal, A.; Basu, K.; and Sen, A. ACM SIGMETRICS Perform. Eval. Rev., 47(4): 8–11. April 2020.
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@article{padhee_identifying_2020, title = {Identifying unique power system signatures for determining vulnerability of critical power system assets}, volume = {47}, url = {https://dl.acm.org/doi/abs/10.1145/3397776.3397779}, abstract = {In this paper, the finer granularity of phasor measurement unit (PMU) data is exploited to develop a data-driven ap- proach for accurate health assessment of large power trans- formers(LPTs). There research demonstrates how variations in signal-to-noiseratios (SNRs) of PMU measurements can be used as a reliable metric for health assessment. However, a single PMU device maybe affected by multiple equipment located in its neighborhood. To address the challenge of identifying the equipment that is primarily responsible for the degradation inquality of the PMU measurements,an in- telligent sensor selection scheme is proposed,which ensures that every critical equipment is associated with a unique identifying signature. The proposed algorithm is based on a real LPT failure event that occurred in the US Southwest. The inferences drawn from the proposed PMU-based health monitoring scheme can be easily supplemented with other LPT sensors to facilitate proactive intervention before the point-of-no-return is reached.}, number = {4}, journal = {ACM SIGMETRICS Perform. Eval. Rev.}, author = {Padhee, Malhar and Biswas, Reetam Sen and Pal, Anamitra and Basu, Kaustav and Sen, Arunabha}, month = apr, year = {2020}, pages = {8--11}, }
In this paper, the finer granularity of phasor measurement unit (PMU) data is exploited to develop a data-driven ap- proach for accurate health assessment of large power trans- formers(LPTs). There research demonstrates how variations in signal-to-noiseratios (SNRs) of PMU measurements can be used as a reliable metric for health assessment. However, a single PMU device maybe affected by multiple equipment located in its neighborhood. To address the challenge of identifying the equipment that is primarily responsible for the degradation inquality of the PMU measurements,an in- telligent sensor selection scheme is proposed,which ensures that every critical equipment is associated with a unique identifying signature. The proposed algorithm is based on a real LPT failure event that occurred in the US Southwest. The inferences drawn from the proposed PMU-based health monitoring scheme can be easily supplemented with other LPT sensors to facilitate proactive intervention before the point-of-no-return is reached.
Critical clearing time sensitivity for inequality constrained systems. Mishra, C.; Biswas, R. S.; Pal, A.; and Centeno, V. A. IEEE Transactions on Power Systems, 35(2): 1572–1583. March 2020.
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@article{mishra_critical_2020, title = {Critical clearing time sensitivity for inequality constrained systems}, volume = {35}, url = {https://ieeexplore.ieee.org/abstract/document/8845608}, abstract = {With the growth of renewable generation (RG) and the development of associated ride through curves serving as operating limits, during disturbances, on violation of these limits, the power system is at risk of losing large amounts of generation. In order to identify preventive control measures that avoid such scenarios from manifesting, the power system must be modeled as a constrained dynamical system. For such systems, the interplay of feasibility region (man-made limits) and stability region (natural dynamical system response) results in a positively invariant region in state space known as the constrained stability region (CSR). After the occurrence of a disturbance, as it is desirable for the system trajectory to lie within the CSR, critical clearing time (CCT) must be defined with respect to the CSR instead of the stability region as is done traditionally. The sensitivity of CCT to system parameters of constrained systems then becomes beneficial for planning/revising protection settings (which impact feasible region) and/or operation (which impact dynamics). In this paper, we derive the first order CCT sensitivity of generic constrained power systems using the efficient power system trajectory sensitivity computation, pioneered by Hiskens and Pai in [“Trajectory sensitivity analysis of hybrid systems,†IEEE Trans. Circuits Syst. Fundam. Theory Appl., vol. 47, no. 2, pp. 204-220, Feb. 2000]. The results are illustrated for a single-machine infinite-bus (SMIB) system as well as a multi-machine system in order to gain meaningful insight into the dependence between ability to meet constraints, system stability, and changes occurring in power system parameters, such as, mechanical power input and inertia.}, number = {2}, journal = {IEEE Transactions on Power Systems}, author = {Mishra, Chetan and Biswas, Reetam Sen and Pal, Anamitra and Centeno, Virgilio A.}, month = mar, year = {2020}, keywords = {Constrained systems, Manifolds, nonlinear dynamical systems, Power system stability, power system transient stability, Sensitivity, Stability criteria, Trajectory}, pages = {1572--1583}, }
With the growth of renewable generation (RG) and the development of associated ride through curves serving as operating limits, during disturbances, on violation of these limits, the power system is at risk of losing large amounts of generation. In order to identify preventive control measures that avoid such scenarios from manifesting, the power system must be modeled as a constrained dynamical system. For such systems, the interplay of feasibility region (man-made limits) and stability region (natural dynamical system response) results in a positively invariant region in state space known as the constrained stability region (CSR). After the occurrence of a disturbance, as it is desirable for the system trajectory to lie within the CSR, critical clearing time (CCT) must be defined with respect to the CSR instead of the stability region as is done traditionally. The sensitivity of CCT to system parameters of constrained systems then becomes beneficial for planning/revising protection settings (which impact feasible region) and/or operation (which impact dynamics). In this paper, we derive the first order CCT sensitivity of generic constrained power systems using the efficient power system trajectory sensitivity computation, pioneered by Hiskens and Pai in [“Trajectory sensitivity analysis of hybrid systems,†IEEE Trans. Circuits Syst. Fundam. Theory Appl., vol. 47, no. 2, pp. 204-220, Feb. 2000]. The results are illustrated for a single-machine infinite-bus (SMIB) system as well as a multi-machine system in order to gain meaningful insight into the dependence between ability to meet constraints, system stability, and changes occurring in power system parameters, such as, mechanical power input and inertia.
Optimal placement,sizing and coordination of FACTS devices in transmission network using whale optimization algorithm. Nadeem, M.; Imran, K.; Khattak, A.; Ulasyar, A.; Pal, A.; Zeb, M. Z.; Khan, A. N.; and Padhee, M. Energies, 13(3): 753. February 2020.
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@article{nadeem_optimal_2020, title = {Optimal placement,sizing and coordination of FACTS devices in transmission network using whale optimization algorithm}, volume = {13}, url = {https://www.mdpi.com/1996-1073/13/3/753}, abstract = {Flexible AC Transmission Systems (FACTS) play an important role in minimizing power losses and voltage deviations while increasing the real power transfer capacity of transmission lines. The extent to which these devices can provide benefits to the transmission network depend on their optimal location and sizing. However, finding appropriate locations and sizes of these devices in an electrical network is difficult since it is a nonlinear problem. This paper proposes a technique for the optimal placement and sizing of FACTS, namely the Thyristor-Controlled Series Compensators (TCSCs), Shunt VARs Compensators (SVCs), and Unified Power Flows Controllers (UPFCs). To find the optimal locations of these devices in a network, weak buses and lines are determined by constructing PV curves of load buses, and through the line stability index. Then, the whale optimization algorithm (WOA) is employed not only to find an ideal ratings for these devices but also the optimal coordination of SVC, TCSC, and UPFC with the reactive power sources already present in the network (tap settings of transformers and reactive power from generators). The objective here is the minimization of the operating cost of the system that consists of active power losses and FACTS devices cost. The proposed method is applied to the IEEE 14 and 30 bus systems. The presented technique is also compared with Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The findings showed that total system operating costs and transmission line losses were considerably reduced by WOA as compared to existing metaheuristic optimization techniques.}, number = {3}, journal = {Energies}, author = {Nadeem, Muhammad and Imran, Kashif and Khattak, Abraiz and Ulasyar, Abasin and Pal, Anamitra and Zeb, Muhammad Zulqarnain and Khan, Atif Naveed and Padhee, Malhar}, month = feb, year = {2020}, keywords = {FACTS, line stability index (L$_{\textrm{mn}}$), PV curves, whale optimization algorithm (WOA)}, pages = {753}, }
Flexible AC Transmission Systems (FACTS) play an important role in minimizing power losses and voltage deviations while increasing the real power transfer capacity of transmission lines. The extent to which these devices can provide benefits to the transmission network depend on their optimal location and sizing. However, finding appropriate locations and sizes of these devices in an electrical network is difficult since it is a nonlinear problem. This paper proposes a technique for the optimal placement and sizing of FACTS, namely the Thyristor-Controlled Series Compensators (TCSCs), Shunt VARs Compensators (SVCs), and Unified Power Flows Controllers (UPFCs). To find the optimal locations of these devices in a network, weak buses and lines are determined by constructing PV curves of load buses, and through the line stability index. Then, the whale optimization algorithm (WOA) is employed not only to find an ideal ratings for these devices but also the optimal coordination of SVC, TCSC, and UPFC with the reactive power sources already present in the network (tap settings of transformers and reactive power from generators). The objective here is the minimization of the operating cost of the system that consists of active power losses and FACTS devices cost. The proposed method is applied to the IEEE 14 and 30 bus systems. The presented technique is also compared with Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The findings showed that total system operating costs and transmission line losses were considerably reduced by WOA as compared to existing metaheuristic optimization techniques.
A micro-PMU placement scheme for distribution systems considering practical constraints. Biswas, R. S.; Azimian, B.; and Pal, A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Montreal, Canada, August 2020.
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@inproceedings{biswas_micro-pmu_2020, address = {Montreal, Canada}, title = {A micro-PMU placement scheme for distribution systems considering practical constraints}, url = {https://ieeexplore.ieee.org/abstract/document/9282049}, abstract = {This paper presents an innovative approach to micro-phasor measurement unit (micro-PMU or μPMU) placement in unbalanced distribution networks. The methodology accounts for the presence of single-and-two-phase laterals and acknowledges the fact that observing one phase in a distribution circuit does not translate to observing the other phases. Other practical constraints such as presence of distributed loads, unknown regulator/ transformer tap ratios, zero-injection phases (ZIPs), modern smart meters, and multiple switch configurations are also incorporated. The proposed μPMU placement problem is solved using integer linear programming (ILP), guaranteeing optimality of results. The uniqueness of the developed algorithm is that it not only minimizes the μPMU installations, but also identifies the minimum number of phases that must be monitored by them.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Biswas, Reetam Sen and Azimian, Behrouz and Pal, Anamitra}, month = aug, year = {2020}, keywords = {Distribution networks, Distribution system, Integer linear programming, Integer programming, Measurement units, Meters, Micro-PMUs, Monitoring, Observability, Smart meter, Smart meters, Switches}, pages = {1--5}, }
This paper presents an innovative approach to micro-phasor measurement unit (micro-PMU or μPMU) placement in unbalanced distribution networks. The methodology accounts for the presence of single-and-two-phase laterals and acknowledges the fact that observing one phase in a distribution circuit does not translate to observing the other phases. Other practical constraints such as presence of distributed loads, unknown regulator/ transformer tap ratios, zero-injection phases (ZIPs), modern smart meters, and multiple switch configurations are also incorporated. The proposed μPMU placement problem is solved using integer linear programming (ILP), guaranteeing optimality of results. The uniqueness of the developed algorithm is that it not only minimizes the μPMU installations, but also identifies the minimum number of phases that must be monitored by them.
Fast identification of saturated cut-sets using graph search techniques. Biswas, R. S.; Pal, A.; Werho, T.; and Vittal, V. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Montreal, Canada, August 2020.
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@inproceedings{biswas_fast_2020, address = {Montreal, Canada}, title = {Fast identification of saturated cut-sets using graph search techniques}, url = {https://ieeexplore.ieee.org/abstract/document/9281500}, abstract = {When multiple outages occur in rapid succession, it is important to know quickly if the power transfer capability of different interconnections (or cut-sets) of the power network are limited. The algorithm developed in this paper identifies such limited cut-sets very fast, thereby enhancing the real-time situational awareness of power system operators. The significance of the proposed approach is described using the IEEE 39-bus test system, while its computational benefits are demonstrated using relatively large test-cases containing thousands of buses. The results indicate that the proposed network analysis can estimate the impact of an outage on any cut-set of the system and screen out the cut-set that gets saturated by the largest margin, very quickly.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Biswas, Reetam Sen and Pal, Anamitra and Werho, Trevor and Vittal, Vijay}, month = aug, year = {2020}, keywords = {Graph theory, Network flow, Power system disturbances, Power systems, Real-time systems, Saturated cut-set}, pages = {1--5}, }
When multiple outages occur in rapid succession, it is important to know quickly if the power transfer capability of different interconnections (or cut-sets) of the power network are limited. The algorithm developed in this paper identifies such limited cut-sets very fast, thereby enhancing the real-time situational awareness of power system operators. The significance of the proposed approach is described using the IEEE 39-bus test system, while its computational benefits are demonstrated using relatively large test-cases containing thousands of buses. The results indicate that the proposed network analysis can estimate the impact of an outage on any cut-set of the system and screen out the cut-set that gets saturated by the largest margin, very quickly.
Adaptive LVRT settings adjustment for enhancing voltage security of renewable-rich electric grids. Wang, C.; Mishra, C.; Biswas, R. S.; Pal, A.; and Centeno, V. A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Montreal, Canada, August 2020.
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@inproceedings{wang_adaptive_2020, address = {Montreal, Canada}, title = {Adaptive LVRT settings adjustment for enhancing voltage security of renewable-rich electric grids}, url = {https://ieeexplore.ieee.org/abstract/document/9282044}, abstract = {Inverter based renewable generation (RG), especially at the distribution level, is supposed to trip offline during an islanding situation. However, islanding detection is done by comparing the voltage and frequency measurements at the point of common coupling (PCC), with limits defined in the form of ride-through curves. Current practice is to use the same limit throughout the year independent of the operating conditions. This could result in the tripping of RG at times when the system is already weak, thereby posing a threat to voltage security by heavily limiting the load margin (LM). Conversely, heavily relaxing these limits would result in scenarios where the generation does not go offline even during an islanding situation. The proposed methodology focuses on optimizing low-voltage ride-through (LVRT) settings at selective RGs as a preventive control for maintaining a desired steady-state voltage stability margin while not sacrificing dependability during islanding. The proposed process is a multi-stage approach, in which at each stage, a subset of estimated poor-quality solutions is screened out based on various sensitivities. A full continuation power flow (CPFLOW) is only run at the beginning and in the last stage on a handful of remaining candidate solutions, thereby cutting down heavily on the computation time. The effectiveness of the approach is demonstrated on the IEEE 9-bus system.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Wang, Chen and Mishra, Chetan and Biswas, Reetam Sen and Pal, Anamitra and Centeno, Virgilio A.}, month = aug, year = {2020}, keywords = {Adaptive control, Continuation power flow, Low voltage, Low-voltage ride-through, Power system stability, Reactive power, Renewable energy, Security, Sensitivity, Steady-state, Voltage control, Voltage security}, pages = {1--5}, }
Inverter based renewable generation (RG), especially at the distribution level, is supposed to trip offline during an islanding situation. However, islanding detection is done by comparing the voltage and frequency measurements at the point of common coupling (PCC), with limits defined in the form of ride-through curves. Current practice is to use the same limit throughout the year independent of the operating conditions. This could result in the tripping of RG at times when the system is already weak, thereby posing a threat to voltage security by heavily limiting the load margin (LM). Conversely, heavily relaxing these limits would result in scenarios where the generation does not go offline even during an islanding situation. The proposed methodology focuses on optimizing low-voltage ride-through (LVRT) settings at selective RGs as a preventive control for maintaining a desired steady-state voltage stability margin while not sacrificing dependability during islanding. The proposed process is a multi-stage approach, in which at each stage, a subset of estimated poor-quality solutions is screened out based on various sensitivities. A full continuation power flow (CPFLOW) is only run at the beginning and in the last stage on a handful of remaining candidate solutions, thereby cutting down heavily on the computation time. The effectiveness of the approach is demonstrated on the IEEE 9-bus system.
A new model to analyze power and communication system intra-and-inter dependencies. Roy, S.; Chandrasekaran, H.; Pal, A.; and Sen, A. In IEEE Conference on Technologies for Sustainability (SusTech), pages 1–8, Santa Ana, CA., April 2020.
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@inproceedings{roy_new_2020, address = {Santa Ana, CA.}, title = {A new model to analyze power and communication system intra-and-inter dependencies}, url = {https://ieeexplore.ieee.org/abstract/document/9150529}, abstract = {The reliable and resilient operation of the smart grid necessitates a clear understanding of the intra-and-inter dependencies of its power and communication systems. This understanding can only be achieved by accurately depicting the interactions between the different components of these two systems. This paper presents a model, called modified implicative interdependency model (MIIM), for capturing these interactions. Data obtained from a power utility in the U.S. Southwest is used to ensure the validity of the model. The performance of the model for a specific power system application namely, state estimation, is demonstrated using the IEEE 118-bus system. The results indicate that the proposed model is more accurate than its predecessor, the implicative interdependency model (IIM) [1], in predicting the system state in case of failures in the power and/or communication systems.}, booktitle = {IEEE Conference on Technologies for Sustainability (SusTech)}, author = {Roy, Sohini and Chandrasekaran, Harish and Pal, Anamitra and Sen, Arunabha}, month = apr, year = {2020}, keywords = {Bandwidth, Inter-dependency relations (IDRs), Logic gates, Phasor measurement unit (PMU), Phasor measurement units, Servers, Smart grid, Smart grids, SONET, State estimation, Substations, Supervisory control and data acquisition (SCADA)}, pages = {1--8}, }
The reliable and resilient operation of the smart grid necessitates a clear understanding of the intra-and-inter dependencies of its power and communication systems. This understanding can only be achieved by accurately depicting the interactions between the different components of these two systems. This paper presents a model, called modified implicative interdependency model (MIIM), for capturing these interactions. Data obtained from a power utility in the U.S. Southwest is used to ensure the validity of the model. The performance of the model for a specific power system application namely, state estimation, is demonstrated using the IEEE 118-bus system. The results indicate that the proposed model is more accurate than its predecessor, the implicative interdependency model (IIM) [1], in predicting the system state in case of failures in the power and/or communication systems.
Incorporation of controlled islanding scenarios and complex substations in optimal WAMS design. Ghamsari-Yazdel, M.; Esmaili, M.; Aminifar, F.; Gupta, P.; Pal, A.; and Shayanfar, H. IEEE Transactions on Power Systems, 34(5): 3408–3416. September 2019.
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@article{ghamsari-yazdel_incorporation_2019, title = {Incorporation of controlled islanding scenarios and complex substations in optimal WAMS design}, volume = {34}, url = {https://ieeexplore.ieee.org/abstract/document/8653428}, abstract = {An efficient wide-area measurement system (WAMS) should be able to preserve system observability in foreseen abnormal situations, such as intentional controlled islanding (ICI). In this paper, an optimal WAMS design model is proposed while ensuring power system observability in the base case and all plausible scenarios of ICI. Thus, quasi-observable states that are undesirable in state estimation are avoided. The model minimizes the cost of substation disruptions imposed by PMU installation and the cost of WAMS components subject to diverse economic and technical constraints. In order to optimally retain system observability in different operational configurations of substations, complex buses of switchgears with bus sectionalizers and couplers are modeled. Also, the indeterminacy of transformer tap ratios is considered to have realistic solutions. The proposed method is examined on IEEE standard test systems as well as Polish 2383-bus and 2746-bus large-scale systems to demonstrate its applicability to real systems.}, number = {5}, journal = {IEEE Transactions on Power Systems}, author = {Ghamsari-Yazdel, Mohammad and Esmaili, Masoud and Aminifar, Farrokh and Gupta, P. and Pal, Anamitra and Shayanfar, Heidarli}, month = sep, year = {2019}, keywords = {Complex bus, intentional controlled islanding (ICI), Islanding, Observability, phasor measurement unit (PMU), Phasor measurement units, Power system stability, Substations, Switches, Voltage measurement, wide area measurement system (WAMS)}, pages = {3408--3416}, }
An efficient wide-area measurement system (WAMS) should be able to preserve system observability in foreseen abnormal situations, such as intentional controlled islanding (ICI). In this paper, an optimal WAMS design model is proposed while ensuring power system observability in the base case and all plausible scenarios of ICI. Thus, quasi-observable states that are undesirable in state estimation are avoided. The model minimizes the cost of substation disruptions imposed by PMU installation and the cost of WAMS components subject to diverse economic and technical constraints. In order to optimally retain system observability in different operational configurations of substations, complex buses of switchgears with bus sectionalizers and couplers are modeled. Also, the indeterminacy of transformer tap ratios is considered to have realistic solutions. The proposed method is examined on IEEE standard test systems as well as Polish 2383-bus and 2746-bus large-scale systems to demonstrate its applicability to real systems.
Transient stability assessment of prone-to-trip renewable generation rich power systems using Lyapunov's direct method. Mishra, C.; Pal, A.; Thorp, J. S.; and Centeno, V. A. IEEE Transactions on Sustainable Energy, 10(3): 1523–1533. July 2019. Conference Name: IEEE Transactions on Sustainable Energy
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@article{mishra_transient_2019, title = {Transient stability assessment of prone-to-trip renewable generation rich power systems using Lyapunov's direct method}, volume = {10}, url = {https://ieeexplore.ieee.org/abstract/document/8668571}, doi = {10.1109/TSTE.2019.2905608}, abstract = {Utilities across the world are seeing increased penetration of inverter-based renewable generation (RG) in their systems. These RGs have ride through curves programmed in them which define operating conditions that need to be satisfied during electrical disturbances. If they are violated, the RGs are tripped offline. In systems with large amounts of RGs tightly coupled electrically, there can be disturbances that cause sudden loss of a large number of RGs, which will then considerably exacerbate the stability of the system. Such a phenomenon is not captured by the existing direct methods for TSA. In this paper, by treating RG-rich systems as non-linear switched systems as opposed to the traditional approach of treating this tripping phenomenon as an instability, an approach utilizing multiple low voltage ride through constrained stability regions (CSRs) is proposed for capturing unstable fault clearing times. The CSRs are estimated through Lyapunov functions found using sum of squares programming. The effectiveness of the proposed technique is demonstrated using a three-machine system.}, number = {3}, journal = {IEEE Transactions on Sustainable Energy}, author = {Mishra, Chetan and Pal, Anamitra and Thorp, James S. and Centeno, Virgilio A.}, month = jul, year = {2019}, note = {Conference Name: IEEE Transactions on Sustainable Energy}, keywords = {Constrained stability region (CSR), Generators, low voltage ride through (LVRT), Lyapunov approach, Power system stability, Stability criteria, sum of squares (SOS) programming, Switched systems, Switches, Trajectory, transient stability assessment (TSA)}, pages = {1523--1533}, }
Utilities across the world are seeing increased penetration of inverter-based renewable generation (RG) in their systems. These RGs have ride through curves programmed in them which define operating conditions that need to be satisfied during electrical disturbances. If they are violated, the RGs are tripped offline. In systems with large amounts of RGs tightly coupled electrically, there can be disturbances that cause sudden loss of a large number of RGs, which will then considerably exacerbate the stability of the system. Such a phenomenon is not captured by the existing direct methods for TSA. In this paper, by treating RG-rich systems as non-linear switched systems as opposed to the traditional approach of treating this tripping phenomenon as an instability, an approach utilizing multiple low voltage ride through constrained stability regions (CSRs) is proposed for capturing unstable fault clearing times. The CSRs are estimated through Lyapunov functions found using sum of squares programming. The effectiveness of the proposed technique is demonstrated using a three-machine system.
Can predictive filters detect gradually ramping false data injection attacks against PMUs?. Chu, Z.; Pinceti, A.; Biswas, R. S.; Kosut, O.; Pal, A.; and Sankar, L. In IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids (SmartGridComm), pages 1–6, Beijing, China, October 2019.
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@inproceedings{chu_can_2019, address = {Beijing, China}, title = {Can predictive filters detect gradually ramping false data injection attacks against PMUs?}, url = {https://ieeexplore.ieee.org/abstract/document/8909739}, abstract = {Intelligently designed false data injection (FDI) attacks have been shown to be able to bypass the χ2-test based bad data detector (BDD), resulting in physical consequences (such as line overloads) in the power system. In this paper, using synthetic PMU measurements and intelligently designed FDI attacks, it is shown that if an attack is suddenly injected into the system, a predictive filter with sufficient accuracy is able to detect it. However, an attacker can gradually increase the magnitude of the attack to avoid detection, and still cause damage to the system.}, booktitle = {IEEE International Conference on Communications, Control, and Computing Technologies for Smart Grids (SmartGridComm)}, author = {Chu, Zhigang and Pinceti, Andrea and Biswas, Reetam Sen and Kosut, Oliver and Pal, Anamitra and Sankar, Lalitha}, month = oct, year = {2019}, keywords = {Current measurement, Phasor measurement units, Smart grids, Time measurement, Transmission line measurements, Voltage measurement}, pages = {1--6}, }
Intelligently designed false data injection (FDI) attacks have been shown to be able to bypass the χ2-test based bad data detector (BDD), resulting in physical consequences (such as line overloads) in the power system. In this paper, using synthetic PMU measurements and intelligently designed FDI attacks, it is shown that if an attack is suddenly injected into the system, a predictive filter with sufficient accuracy is able to detect it. However, an attacker can gradually increase the magnitude of the attack to avoid detection, and still cause damage to the system.
A PMU based islanding detection scheme immune to additive instrumentation channel errors. Barkakati, M.; Biswas, R. S.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Wichita, KS., October 2019.
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@inproceedings{barkakati_pmu_2019, address = {Wichita, KS.}, title = {A PMU based islanding detection scheme immune to additive instrumentation channel errors}, url = {https://ieeexplore.ieee.org/abstract/document/9000222}, doi = {10.1109/NAPS46351.2019.9000222}, abstract = {Traditional synchrophasor measurement-based islanding detection techniques have primarily relied on voltage angle measurements and/or their derivatives for successfully detecting islands. However, relatively high instrumentation channel errors associated with phasor measurement unit (PMU) data, can significantly degrade islanding detection accuracies. In this paper, a new islanding detection scheme employing cumulative sum of change in voltage phase angle difference (CUSPAD) is proposed, which is immune to additive instrumentation channel errors in the PMU measurements. The robustness of the proposed islanding detection algorithm is established through application to an 18-bus test system and the IEEE 118-bus system having different wind energy penetration levels. Comparative analysis of the accuracies of the proposed approach (CUSPAD) and the conventional angle difference (AD) approach prove the former's superior performance when additive instrumentation channel errors are present.}, booktitle = {North American Power Symposium (NAPS)}, author = {Barkakati, Meghna and Biswas, Reetam Sen and Pal, Anamitra}, month = oct, year = {2019}, keywords = {Additives, Data mining, Instrumentation channel error, Instruments, Islanding, Islanding detection, Phase measurement, Phasor measurement unit (PMU), Phasor measurement units, Voltage measurement, Wind energy}, pages = {1--6}, }
Traditional synchrophasor measurement-based islanding detection techniques have primarily relied on voltage angle measurements and/or their derivatives for successfully detecting islands. However, relatively high instrumentation channel errors associated with phasor measurement unit (PMU) data, can significantly degrade islanding detection accuracies. In this paper, a new islanding detection scheme employing cumulative sum of change in voltage phase angle difference (CUSPAD) is proposed, which is immune to additive instrumentation channel errors in the PMU measurements. The robustness of the proposed islanding detection algorithm is established through application to an 18-bus test system and the IEEE 118-bus system having different wind energy penetration levels. Comparative analysis of the accuracies of the proposed approach (CUSPAD) and the conventional angle difference (AD) approach prove the former's superior performance when additive instrumentation channel errors are present.
Application of machine learning for online dynamic security assessment in presence of system variability and additive instrumentation errors. Nath, A.; Biswas, R. S.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Wichita, KS., October 2019.
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@inproceedings{nath_application_2019, address = {Wichita, KS.}, title = {Application of machine learning for online dynamic security assessment in presence of system variability and additive instrumentation errors}, url = {https://ieeexplore.ieee.org/abstract/document/9000333}, abstract = {Large-scale blackouts that have occurred in the past few decades have necessitated the need to do extensive research in the field of grid security assessment. With the aid of synchrophasor technology, which uses phasor measurement unit (PMU) data, dynamic security assessment (DSA) can be performed online. However, existing applications of DSA are challenged by variability in system conditions and unaccounted for measurement errors. To overcome these challenges, this research develops a DSA scheme to provide security prediction in real-time for load profiles of different seasons in presence of realistic errors in the PMU measurements. The major contributions of this paper are: (1) develop a DSA scheme based on PMU data, (2) consider seasonal load profiles, (3) account for varying penetrations of renewable generation, and (4) compare the accuracy of different machine learning (ML) algorithms for DSA with and without erroneous measurements. The performance of this approach is tested on the IEEE-118 bus system. Comparative analysis of the accuracies of the ML algorithms under different operating scenarios highlights the importance of considering realistic errors and variability in system conditions while creating a DSA scheme.}, booktitle = {North American Power Symposium (NAPS)}, author = {Nath, Anubhav and Biswas, Reetam Sen and Pal, Anamitra}, month = oct, year = {2019}, keywords = {Databases, Dynamic Security Assessment (DSA), Load modeling, Machine Learning (ML), Phasor Measurement Unit (PMU), Phasor measurement units, Power system stability, Renewable Generation, Security, Transient analysis, Voltage measurement}, pages = {1--6}, }
Large-scale blackouts that have occurred in the past few decades have necessitated the need to do extensive research in the field of grid security assessment. With the aid of synchrophasor technology, which uses phasor measurement unit (PMU) data, dynamic security assessment (DSA) can be performed online. However, existing applications of DSA are challenged by variability in system conditions and unaccounted for measurement errors. To overcome these challenges, this research develops a DSA scheme to provide security prediction in real-time for load profiles of different seasons in presence of realistic errors in the PMU measurements. The major contributions of this paper are: (1) develop a DSA scheme based on PMU data, (2) consider seasonal load profiles, (3) account for varying penetrations of renewable generation, and (4) compare the accuracy of different machine learning (ML) algorithms for DSA with and without erroneous measurements. The performance of this approach is tested on the IEEE-118 bus system. Comparative analysis of the accuracies of the ML algorithms under different operating scenarios highlights the importance of considering realistic errors and variability in system conditions while creating a DSA scheme.
A comprehensive data driven outage analysis for assessing reliability of the bulk power system. Barkakati, M.; and Pal, A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Atlanta, GA., August 2019.
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@inproceedings{barkakati_comprehensive_2019, address = {Atlanta, GA.}, title = {A comprehensive data driven outage analysis for assessing reliability of the bulk power system}, url = {https://ieeexplore.ieee.org/abstract/document/8974110}, abstract = {This paper presents a comprehensive overview of how historical outage data can be analyzed to determine the reliability of the bulk power system (BPS) using both outage frequency and outage duration metrics. In addition to outage analysis, different outage categories are analyzed and prioritized according to their outage severity level. A new reliability indicator, Outage Impact Index (OII) is also proposed which identifies annual system risks for a given voltage class. The key performance indices discussed in this paper can be used by power utilities to quantify and assess transmission system performance, establish baselines from chronological trends, and minimize system risks by developing corrective measures.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Barkakati, Meghna and Pal, Anamitra}, month = aug, year = {2019}, keywords = {Bulk power system (BPS), outage duration, outage frequency, reliability indices, statistical analysis}, pages = {1--5}, }
This paper presents a comprehensive overview of how historical outage data can be analyzed to determine the reliability of the bulk power system (BPS) using both outage frequency and outage duration metrics. In addition to outage analysis, different outage categories are analyzed and prioritized according to their outage severity level. A new reliability indicator, Outage Impact Index (OII) is also proposed which identifies annual system risks for a given voltage class. The key performance indices discussed in this paper can be used by power utilities to quantify and assess transmission system performance, establish baselines from chronological trends, and minimize system risks by developing corrective measures.
Critical clearing time sensitivity for inequality constrained systems. Mishra, C.; Pal, A.; and Centeno, V. A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Atlanta, GA., August 2019. ISSN: 1944-9933
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@inproceedings{mishra_critical_2019, address = {Atlanta, GA.}, title = {Critical clearing time sensitivity for inequality constrained systems}, doi = {https://ieeexplore.ieee.org/abstract/document/8973983}, abstract = {From a stability perspective, a renewable generation (RG)-rich power system is a constrained system. As the quasi-stability boundary of a constrained system is structurally very different from that of an unconstrained system, finding the sensitivity of critical clearing time (CCT) to change in system parameters is very beneficial for a constrained power system, especially for planning/revising constraints arising from system protection settings. In this paper, we derive the first order sensitivity of a constrained power system using trajectory sensitivities of fault-on and post-fault trajectories. The results for the test system demonstrate the dependence between ability to meet angle and frequency constraints, and change in power system parameters such as operating conditions and inertia.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Mishra, Chetan and Pal, Anamitra and Centeno, Virgilio A.}, month = aug, year = {2019}, note = {ISSN: 1944-9933}, keywords = {Constrained systems, Nonlinear dynamical systems, Power system transient stability}, pages = {1--5}, }
From a stability perspective, a renewable generation (RG)-rich power system is a constrained system. As the quasi-stability boundary of a constrained system is structurally very different from that of an unconstrained system, finding the sensitivity of critical clearing time (CCT) to change in system parameters is very beneficial for a constrained power system, especially for planning/revising constraints arising from system protection settings. In this paper, we derive the first order sensitivity of a constrained power system using trajectory sensitivities of fault-on and post-fault trajectories. The results for the test system demonstrate the dependence between ability to meet angle and frequency constraints, and change in power system parameters such as operating conditions and inertia.
Design of a coordinated wide area damping controller by employing partial state feedback. Gupta, P.; Pal, A.; Mishra, C.; and Wang, T. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Atlanta, GA., August 2019.
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@inproceedings{gupta_design_2019, address = {Atlanta, GA.}, title = {Design of a coordinated wide area damping controller by employing partial state feedback}, url = {https://ieeexplore.ieee.org/abstract/document/8973776}, abstract = {For continued reliability and stability of the modern power system, the new controls that are designed for it, must be functionally flexible and computationally advanced. In accordance with this realization, this paper presents the design of a coordinated wide-area damping controller (CWADC) that employs a partial state feedback control mechanism for damping inter-area oscillations. For developing the control, an enhanced version of selective modal analysis (SMA) is proposed, which is then combined with a linear matrix inequality (LMI)-based polytope. To ensure robustness of the control, the option of selecting PMU inputs from alternate locations is also explored. A 16 machine, 68 bus test system is used to illustrate the proposed technique, while a 29 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system is used to demonstrate its applicability to larger systems.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Gupta, Pooja and Pal, Anamitra and Mishra, Chetan and Wang, Tong}, month = aug, year = {2019}, keywords = {Coordinated wide-area damping controller (CWADC), inter-area oscillations, linear matrix inequality (LMI), partial state feedback, phasor measurement units (PMUs), polytopic control, selective modal analysis (SMA)}, pages = {1--5}, }
For continued reliability and stability of the modern power system, the new controls that are designed for it, must be functionally flexible and computationally advanced. In accordance with this realization, this paper presents the design of a coordinated wide-area damping controller (CWADC) that employs a partial state feedback control mechanism for damping inter-area oscillations. For developing the control, an enhanced version of selective modal analysis (SMA) is proposed, which is then combined with a linear matrix inequality (LMI)-based polytope. To ensure robustness of the control, the option of selecting PMU inputs from alternate locations is also explored. A 16 machine, 68 bus test system is used to illustrate the proposed technique, while a 29 machine, 127 bus equivalent model of the Western Electricity Coordinating Council (WECC) system is used to demonstrate its applicability to larger systems.
Cascading effects of targeted attacks on the power grid. Meyur, R.; Vullikanti, A.; Marathe, M. V.; Pal, A.; Youssef, M.; and Centeno, V. In Aiello, L. M.; Cherifi, C.; Cherifi, H.; Lambiotte, R.; Lió, P.; and Rocha, L. M., editor(s), Proc. Int. Workshop Complex Networks and their Applications, pages 155–167, Cambridge, UK, 2019.
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@inproceedings{meyur_cascading_2019, address = {Cambridge, UK}, title = {Cascading effects of targeted attacks on the power grid}, url = {https://link.springer.com/chapter/10.1007/978-3-030-05411-3_13}, abstract = {We study the resilience of real world power grids to targeted adversarial attacks. Prior blackouts have shown that failures in the power grid can cascade, starting from a single failure, leading to a large number of failed nodes. In this paper, we study the problem of identifying a set of k critical nodes, whose failure/attack leads to the maximum number of tripped nodes. There has been a lot of work on this problem, but it has been mainly restricted to simple networks and failure models with either steady state analysis or DC power flow. In this paper, we perform AC power flow based transient analysis on a detailed power grid model. We find that a simple greedy approach yields node sets with higher criticality than a degree based approach, which has been suggested in many prior works. Furthermore, we observe that the cascades exhibit a non-monotonic behavior as a function of k.}, booktitle = {Proc. Int. Workshop Complex Networks and their Applications}, author = {Meyur, Rounak and Vullikanti, Anil and Marathe, Madhav V. and Pal, Anamitra and Youssef, Mina and Centeno, Virgilio}, editor = {Aiello, Luca Maria and Cherifi, Chantal and Cherifi, Hocine and Lambiotte, Renaud and Lió, Pietro and Rocha, Luis M.}, year = {2019}, keywords = {Hidden Failures, Maximum Criticality, Power Flow, Power Grid, Target Node Set}, pages = {155--167}, }
We study the resilience of real world power grids to targeted adversarial attacks. Prior blackouts have shown that failures in the power grid can cascade, starting from a single failure, leading to a large number of failed nodes. In this paper, we study the problem of identifying a set of k critical nodes, whose failure/attack leads to the maximum number of tripped nodes. There has been a lot of work on this problem, but it has been mainly restricted to simple networks and failure models with either steady state analysis or DC power flow. In this paper, we perform AC power flow based transient analysis on a detailed power grid model. We find that a simple greedy approach yields node sets with higher criticality than a degree based approach, which has been suggested in many prior works. Furthermore, we observe that the cascades exhibit a non-monotonic behavior as a function of k.
Health Monitoring of Critical Power System Equipments Using Identifying Codes. Basu, K.; Padhee, M.; Roy, S.; Pal, A.; Sen, A.; Rhodes, M.; and Keel, B. Critical Information Infrastructures Security , pages 29–41. Springer International Publishing, Kaunas, Lithuania, 2019.
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@InBook{basu_health_2019, address = {Kaunas, Lithuania}, title = {Critical Information Infrastructures Security }, chapter = {Health Monitoring of Critical Power System Equipments Using Identifying Codes}, author = {Basu, Kaustav and Padhee, Malhar and Roy, Sohini and Pal, Anamitra and Sen, Arunabha and Rhodes, Matthew and Keel, Brian}, url = {https://link.springer.com/chapter/10.1007/978-3-030-05849-4_3}, abstract = {High voltage power transformers are one of the most critical equipments in the electric power grid. A sudden failure of a power transformer can significantly disrupt bulk power delivery. Before a transformer reaches its critical failure state, there are indicators which, if monitored periodically, can alert an operator that the transformer is heading towards a failure. One of the indicators is the signal to noise ratio (SNR) of the voltage and current signals in substations located in the vicinity of the transformer. During normal operations, the width of the SNR band is small. However, when the transformer heads towards a failure, the widths of the bands increase, reaching their maximum just before the failure actually occurs. This change in width of the SNR can be observed by sensors, such as phasor measurement units (PMUs) located nearby. Identifying Code is a mathematical tool that enables one to uniquely identify one or more objects of interest, by generating a unique signature corresponding to those objects, which can then be detected by a sensor. In this paper, we first describe how Identifying Code can be utilized for detecting failure of power transformers. Then, we apply this technique to determine the fewest number of sensors needed to uniquely identify failing transformers in different test systems.}, publisher = {Springer International Publishing}, year = {2019}, keywords = {Identifying codes, PMU placement, Transformer health}, pages = {29--41}, }
High voltage power transformers are one of the most critical equipments in the electric power grid. A sudden failure of a power transformer can significantly disrupt bulk power delivery. Before a transformer reaches its critical failure state, there are indicators which, if monitored periodically, can alert an operator that the transformer is heading towards a failure. One of the indicators is the signal to noise ratio (SNR) of the voltage and current signals in substations located in the vicinity of the transformer. During normal operations, the width of the SNR band is small. However, when the transformer heads towards a failure, the widths of the bands increase, reaching their maximum just before the failure actually occurs. This change in width of the SNR can be observed by sensors, such as phasor measurement units (PMUs) located nearby. Identifying Code is a mathematical tool that enables one to uniquely identify one or more objects of interest, by generating a unique signature corresponding to those objects, which can then be detected by a sensor. In this paper, we first describe how Identifying Code can be utilized for detecting failure of power transformers. Then, we apply this technique to determine the fewest number of sensors needed to uniquely identify failing transformers in different test systems.
Error reduction of phasor measurement unit data considering practical constraints. Chatterjee, P.; Pal, A.; Thorp, J. S.; Lopez, J. D. L. R.; and Centeno, V. A. IET Generation, Transmission & Distribution, 12(10): 2332–2339. May 2018.
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@article{chatterjee_error_2018, title = {Error reduction of phasor measurement unit data considering practical constraints}, volume = {12}, url = {https://digital-library.theiet.org/content/journals/10.1049/iet-gtd.2017.1359}, abstract = {Wide area measurement system relies on phasor measurement unit (PMU) data to monitor, protect, and control high-voltage transmission networks. However, errors in instrument transformers (ITs) located at the inputs of a PMU can significantly degrade its output quality. This study proposes two methodologies for voltage and current transformers calibration using PMU data. The first method calibrates ITs using one good quality voltage measurement located at a tie-line. This method tolerates errors in both the ITs (which are to be estimated) as well as the PMUs. The second method attains the same objective as the first one, with the additional constraint that some portion of the data is unusable. Thus, the second method can be used even when the incoming data is intermittent.}, number = {10}, journal = {IET Generation, Transmission \& Distribution}, author = {Chatterjee, Paroma and Pal, Anamitra and Thorp, James S. and Lopez, Jaime De La Ree and Centeno, Virgilio A.}, month = may, year = {2018}, pages = {2332--2339}, }
Wide area measurement system relies on phasor measurement unit (PMU) data to monitor, protect, and control high-voltage transmission networks. However, errors in instrument transformers (ITs) located at the inputs of a PMU can significantly degrade its output quality. This study proposes two methodologies for voltage and current transformers calibration using PMU data. The first method calibrates ITs using one good quality voltage measurement located at a tie-line. This method tolerates errors in both the ITs (which are to be estimated) as well as the PMUs. The second method attains the same objective as the first one, with the additional constraint that some portion of the data is unusable. Thus, the second method can be used even when the incoming data is intermittent.
SDAE-based probabilistic stability analysis of wind integrated power systems. Wang, T.; Yang, J.; Liu, J.; Gupta, P.; Pal, A.; and Deng, J. In 2nd IEEE Conference Energy Internet and Energy System Integration (EI2), pages 1–6, Beijing, China, October 2018.
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@inproceedings{wang_sdae-based_2018, address = {Beijing, China}, title = {SDAE-based probabilistic stability analysis of wind integrated power systems}, url = {https://ieeexplore.ieee.org/abstract/document/8582603}, abstract = {This paper proposes a method for investigating the stability of the power system in presence of significant amounts of wind generation using stochastic differential algebraic equations (SDAEs). Contrary to the traditional approach of modelling the stochasticity only in the initial conditions, the SDAE-based method (SDAEM) describes wind power variation as a continuous stochastic process. Next, the model of a doubly fed induction generator (DFIG) grid-connected power system is also expressed as a SDAE. Finally, the probabilistic small signal stability (PSSS) and the probabilistic transient stability (PTS) conditions are defined. A single machine infinite bus (SMIB) system and a 16-machine, 68-bus system are used as the test systems for this analysis. The results indicate that SDAEM is more accurate and reliable in describing the system conditions in presence of stochastic inputs, and thus can be used to decide the right course of controller action.}, booktitle = {2nd IEEE Conference Energy Internet and Energy System Integration (EI2)}, author = {Wang, Tong and Yang, Jing and Liu, Jiuliang and Gupta, Pooja and Pal, Anamitra and Deng, Jun}, month = oct, year = {2018}, keywords = {Generators, Mathematical model, power system stability, Power system stability, Probabilistic logic, probabilistic stability, Stability analysis, stochastic differential algebraic equations, Stochastic processes, wind power, Wind power generation}, pages = {1--6}, }
This paper proposes a method for investigating the stability of the power system in presence of significant amounts of wind generation using stochastic differential algebraic equations (SDAEs). Contrary to the traditional approach of modelling the stochasticity only in the initial conditions, the SDAE-based method (SDAEM) describes wind power variation as a continuous stochastic process. Next, the model of a doubly fed induction generator (DFIG) grid-connected power system is also expressed as a SDAE. Finally, the probabilistic small signal stability (PSSS) and the probabilistic transient stability (PTS) conditions are defined. A single machine infinite bus (SMIB) system and a 16-machine, 68-bus system are used as the test systems for this analysis. The results indicate that SDAEM is more accurate and reliable in describing the system conditions in presence of stochastic inputs, and thus can be used to decide the right course of controller action.
Health monitoring of critical power system equipments using identifying codes. Basu, K.; Padhee, M.; Roy, S.; Pal, A.; Sen, A.; Rhodes, M.; and Keel, B. In Proc 13th Int. Conf. Critical Information Infrastructures Security (CRITIS), pages 1–12, Kaunas, Lithuania, Sep 2018.
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@inproceedings{basu_health_2018, author = {Basu, Kaustav and Padhee, Malhar and Roy, Sohini and Pal, Anamitra and Sen, Arunabha and Rhodes, Matthew and Keel, Brian}, pages = {1--12}, title = {Health monitoring of critical power system equipments using identifying codes}, year = {2018}, month = {Sep}, address = {Kaunas, Lithuania}, booktitle = {Proc 13th Int. Conf. Critical Information Infrastructures Security (CRITIS)} }
Effect of solar PV penetration on residential energy consumption pattern. Padhee, M.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Fargo, ND, September 2018.
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@inproceedings{padhee_effect_2018, address = {Fargo, ND}, title = {Effect of solar PV penetration on residential energy consumption pattern}, url = {https://ieeexplore.ieee.org/abstract/document/8600657}, abstract = {The residential rooftop solar penetration in the U.S. has increased rapidly over the past few years. This increase, if not properly accounted for, can lead to operational and reliability challenges for the electric power industry in the form of under-utilization of available energy, increase in costs, and reduction in environmental benefits, as demonstrated by the California Independent System Operator (CAISO) Duck Curve. The authors of this paper had previously developed a bottom-up approach for computing season-wise household-level residential energy consumption profiles using a synthetic population resource. In this paper, that model is enhanced to account for the effects that increasing percentages of rooftop solar penetration can have on the residential energy demand profiles of different regions. This information will be very useful to electric power utilities because it will help them efficiently manage the increasing numbers of residential rooftop solar installations in their supply areas.}, booktitle = {North American Power Symposium (NAPS)}, author = {Padhee, Malhar and Pal, Anamitra}, month = sep, year = {2018}, keywords = {Clouds, Computational modeling, Energy consumption, Energy demand modeling, Power systems, residential energy consumption, rooftop solar photovoltaic (PV), seasonal variation, Sociology, Springs, Statistics, synthetic population}, pages = {1--6}, }
The residential rooftop solar penetration in the U.S. has increased rapidly over the past few years. This increase, if not properly accounted for, can lead to operational and reliability challenges for the electric power industry in the form of under-utilization of available energy, increase in costs, and reduction in environmental benefits, as demonstrated by the California Independent System Operator (CAISO) Duck Curve. The authors of this paper had previously developed a bottom-up approach for computing season-wise household-level residential energy consumption profiles using a synthetic population resource. In this paper, that model is enhanced to account for the effects that increasing percentages of rooftop solar penetration can have on the residential energy demand profiles of different regions. This information will be very useful to electric power utilities because it will help them efficiently manage the increasing numbers of residential rooftop solar installations in their supply areas.
Estimation of transmission line sequence impedances using real PMU data. Mansani, P. K.; Pal, A.; Rhodes, M.; and Keel, B. In IEEE North American Power Symposium (NAPS), pages 1–6, Fargo, ND, September 2018.
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@inproceedings{mansani_estimation_2018, address = {Fargo, ND}, title = {Estimation of transmission line sequence impedances using real PMU data}, url = {https://ieeexplore.ieee.org/abstract/document/8600605}, abstract = {Accurate knowledge of transmission line parameters in general, and sequence impedances, in particular, plays an important role in state estimation, fault detection, and adjustment of relay settings. Line parameter estimation using online methods has attracted considerable interest with the widespread installation of phasor measurement units (PMUs). Although various methods have been proposed in the literature for line parameter estimation, most of them have been tested on purely synthetic datasets. A synthetic dataset does not capture the nuances of real data, such as measurement invariance and realistic field noise. Therefore, the algorithms developed using synthetic datasets may not be as effective when used in practice. In this paper, a three-stage test procedure is developed to compare the performance of two algorithms, namely, moving-window total least squares (MWTLS) recursive Kalman filter (RKF), on real PMU data. The results prove that RKF is better than MWTLS. This paper also proposes using ASPEN data as an initial estimate to RKF for further improving its performance. Finally, to circumvent the problems faced due to data dropouts, an auto regressive integrated moving average (ARIMA) model is implemented to predict the variations in sequence impedances.}, booktitle = {IEEE North American Power Symposium (NAPS)}, author = {Mansani, Prashanth Kumar and Pal, Anamitra and Rhodes, Matthew and Keel, Brian}, month = sep, year = {2018}, keywords = {ARIMA, ASPEN, Current measurement, Kalman filters, parameter estimation, phasor measurement unit (PMU), Phasor measurement units, Power transmission lines, recursive Kalman filter (RKF), total least squares (TLS), Transmission line matrix methods, Transmission line measurements, Voltage measurement}, pages = {1--6}, }
Accurate knowledge of transmission line parameters in general, and sequence impedances, in particular, plays an important role in state estimation, fault detection, and adjustment of relay settings. Line parameter estimation using online methods has attracted considerable interest with the widespread installation of phasor measurement units (PMUs). Although various methods have been proposed in the literature for line parameter estimation, most of them have been tested on purely synthetic datasets. A synthetic dataset does not capture the nuances of real data, such as measurement invariance and realistic field noise. Therefore, the algorithms developed using synthetic datasets may not be as effective when used in practice. In this paper, a three-stage test procedure is developed to compare the performance of two algorithms, namely, moving-window total least squares (MWTLS) recursive Kalman filter (RKF), on real PMU data. The results prove that RKF is better than MWTLS. This paper also proposes using ASPEN data as an initial estimate to RKF for further improving its performance. Finally, to circumvent the problems faced due to data dropouts, an auto regressive integrated moving average (ARIMA) model is implemented to predict the variations in sequence impedances.
Impact of false data detection on cloud hosted linear state estimator performance. Chakati, V.; Pore, M.; Banerjee, A.; Pal, A.; and Gupta, S. K. In 2018 IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Portland, OR, August 2018.
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@inproceedings{chakati_impact_2018, address = {Portland, OR}, title = {Impact of false data detection on cloud hosted linear state estimator performance}, url = {https://ieeexplore.ieee.org/abstract/document/8586671}, abstract = {Linear state estimation (LSE) is used to compute the complex voltages of a power system using measurements obtained only from phasor measurement units (PMUs). With the continued addition of PMUs into the grid, classical LSE solvers would have to handle large sets of high-speed data. Furthermore, security threats in the form of false data injection (FDI) attacks must also be considered in the design, which will considerably add to the computational overhead of LSE solvers. Although installing additional computation and communication hardware is a possible solution, such a solution would incur substantial infrastructure and operation costs. In this paper, we explore the design of a cost-effective and scalable cloud hosted LSE (CLSE) solver that also has false data detection (FDD). The proposed CLSE-FDD application exploits GPU parallel processing capabilities for mitigating the performance overhead of FDD to match the operation speed of classical LSE solvers. Results indicate that the GPU based CLSE-FDD application can easily scale in excess of 1,500 PMU installations.}, booktitle = {2018 {IEEE} {Power} {Energy} {Society} {General} {Meeting} ({PESGM})}, author = {Chakati, Vinaya and Pore, Madhurima and Banerjee, Ayan and Pal, Anamitra and Gupta, Sandeep K.S.}, month = aug, year = {2018}, keywords = {Cloud Computing, Covariance matrices, Current measurement, False Data Detection, GPU, Graphics processing units, Linear State Estimation, Phasor Measurement Unit (PMU), Phasor measurement units, State estimation, Task analysis, Voltage measurement}, pages = {1--5}, }
Linear state estimation (LSE) is used to compute the complex voltages of a power system using measurements obtained only from phasor measurement units (PMUs). With the continued addition of PMUs into the grid, classical LSE solvers would have to handle large sets of high-speed data. Furthermore, security threats in the form of false data injection (FDI) attacks must also be considered in the design, which will considerably add to the computational overhead of LSE solvers. Although installing additional computation and communication hardware is a possible solution, such a solution would incur substantial infrastructure and operation costs. In this paper, we explore the design of a cost-effective and scalable cloud hosted LSE (CLSE) solver that also has false data detection (FDD). The proposed CLSE-FDD application exploits GPU parallel processing capabilities for mitigating the performance overhead of FDD to match the operation speed of classical LSE solvers. Results indicate that the GPU based CLSE-FDD application can easily scale in excess of 1,500 PMU installations.
Transient stability assessment of cascade tripping of renewable sources using SOS. Mishra, C.; Thorp, J. S.; Centeno, V. A.; and Pal, A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Portland, OR, August 2018.
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@inproceedings{mishra_transient_2018, address = {Portland, OR}, title = {Transient stability assessment of cascade tripping of renewable sources using SOS}, url = {https://ieeexplore.ieee.org/abstract/document/8586291}, abstract = {There has been significant increase in penetration of renewable generation (RG) sources all over the world. Localized concentration of many such generators could initiate a cascade tripping sequence that might threaten the stability of the entire system. Understanding the impact of cascade tripping process would help the system planner identify trip sequences that must be blocked in order to increase stability. In this work, we attempt to understand the consequences of cascade tripping mechanism through a Lyapunov approach. A conservative definition for the stability region (SR) along with its estimation for a given cascading sequence using sum of squares (SOS) programming is proposed. Finally, a simple probabilistic definition of the SR is used to visualize the risk of instability and understand the impact of blocking trip sequences. A 3-machine system with significant RG penetration is used to demonstrate the idea.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Mishra, Chetan and Thorp, James S. and Centeno, Virgilio A. and Pal, Anamitra}, month = aug, year = {2018}, keywords = {Cascade tripping, Load modeling, Power system stability, renewable generation (RG), Stability criteria, stability region (SR), sum of squares (SOS), switched systems, Switched systems, Switches, Trajectory}, pages = {1--5}, }
There has been significant increase in penetration of renewable generation (RG) sources all over the world. Localized concentration of many such generators could initiate a cascade tripping sequence that might threaten the stability of the entire system. Understanding the impact of cascade tripping process would help the system planner identify trip sequences that must be blocked in order to increase stability. In this work, we attempt to understand the consequences of cascade tripping mechanism through a Lyapunov approach. A conservative definition for the stability region (SR) along with its estimation for a given cascading sequence using sum of squares (SOS) programming is proposed. Finally, a simple probabilistic definition of the SR is used to visualize the risk of instability and understand the impact of blocking trip sequences. A 3-machine system with significant RG penetration is used to demonstrate the idea.
Estimating relevant portion of stability region using Lyapunov approach and sum of squares. Mishra, C.; Thorp, J. S.; Centeno, V. A.; and Pal, A. In IEEE Power Energy Society General Meeting (PESGM), pages 1–5, Portland, OR, August 2018.
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@inproceedings{mishra_estimating_2018, address = {Portland, OR}, title = {Estimating relevant portion of stability region using Lyapunov approach and sum of squares}, url = {https://ieeexplore.ieee.org/abstract/document/8586345}, abstract = {Traditional Lyapunov-based transient stability assessment approaches focus on identifying the stability region (SR) of the equilibrium point under study. When trying to estimate this region using Lyapunov functions, the shape of the final estimate is often limited by the degree of the function chosen - a limitation that results in conservativeness in the estimate of the SR. More conservative the estimate is in a particular region in state space, smaller is the estimate of the critical clearing time (CCT) for disturbances that drive the system towards that region. In order to reduce this conservativeness, we propose a methodology that uses the disturbance trajectory data to skew the shape of the final Lyapunov-based SR estimate. We exploit the advances made in the theory of sum of squares decomposition to algorithmically estimate this region. The effectiveness of this technique is demonstrated on a power systems classical model.}, booktitle = {IEEE Power Energy Society General Meeting (PESGM)}, author = {Mishra, Chetan and Thorp, James S. and Centeno, Virgilio A. and Pal, Anamitra}, month = aug, year = {2018}, keywords = {direct methods, Level set, Lyapunov estimate, Lyapunov methods, Power system stability, Relevant stability region, Stability criteria, sum of squares (SOS), Thermal stability, Trajectory}, pages = {1--5}, }
Traditional Lyapunov-based transient stability assessment approaches focus on identifying the stability region (SR) of the equilibrium point under study. When trying to estimate this region using Lyapunov functions, the shape of the final estimate is often limited by the degree of the function chosen - a limitation that results in conservativeness in the estimate of the SR. More conservative the estimate is in a particular region in state space, smaller is the estimate of the critical clearing time (CCT) for disturbances that drive the system towards that region. In order to reduce this conservativeness, we propose a methodology that uses the disturbance trajectory data to skew the shape of the final Lyapunov-based SR estimate. We exploit the advances made in the theory of sum of squares decomposition to algorithmically estimate this region. The effectiveness of this technique is demonstrated on a power systems classical model.
Using activity patterns to place electric vehicle charging stations in urban regions. Pal, A.; Rangudu, P.; Ravi, S. S.; and Vullikanti, A. K. In IEEE Workshop Parallel Distributed Processing Computational Social Systems (IPDPS), pages 1143–1152, Vancouver, Canada, May 2018.
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@inproceedings{pal_using_2018, address = {Vancouver, Canada}, title = {Using activity patterns to place electric vehicle charging stations in urban regions}, url = {https://ieeexplore.ieee.org/abstract/document/8425543}, abstract = {There is growing interest in the adoption of electric vehicles (EVs) in urban regions. However, because of the limited battery range, the EV charging station infrastructure needs to be significantly expanded. We introduce EVChargingStation, the problem of optimizing charging stations so that each EV can be charged at a location within a certain service distance. Our formulation explicitly incorporates urban activity patterns, and considers multiple types of charging stations. We show that EVChargingStation is NP-hard, in general, and present approximation algorithms with provable performance guarantees. We evaluate one of our algorithms using a detailed urban activity model for the city of Portland, OR. Our results show a tradeoff between the number of charging stations and the maximum service distance, thus providing a systematic methodology for urban planners to evaluate policies for increasing EV deployment. We also show that considering such activity patterns is necessary, in the sense that deploying charging stations at "high traffic" locations can lead to significantly worse solutions.}, booktitle = {IEEE Workshop Parallel Distributed Processing Computational Social Systems (IPDPS)}, author = {Pal, Anamitra and Rangudu, Pavan and Ravi, S. S. and Vullikanti, Anil K.}, month = may, year = {2018}, keywords = {approximation algorithms, Approximation algorithms, Batteries, charging stations, Charging stations, Electric vehicle charging, electric vehicles, Systematics, urban activity patterns, Urban areas}, pages = {1143--1152}, }
There is growing interest in the adoption of electric vehicles (EVs) in urban regions. However, because of the limited battery range, the EV charging station infrastructure needs to be significantly expanded. We introduce EVChargingStation, the problem of optimizing charging stations so that each EV can be charged at a location within a certain service distance. Our formulation explicitly incorporates urban activity patterns, and considers multiple types of charging stations. We show that EVChargingStation is NP-hard, in general, and present approximation algorithms with provable performance guarantees. We evaluate one of our algorithms using a detailed urban activity model for the city of Portland, OR. Our results show a tradeoff between the number of charging stations and the maximum service distance, thus providing a systematic methodology for urban planners to evaluate policies for increasing EV deployment. We also show that considering such activity patterns is necessary, in the sense that deploying charging stations at "high traffic" locations can lead to significantly worse solutions.
A new model to analyze power system dependencies. Padhee, M.; Banerjee, J.; Basu, K.; Roy, S.; Pal, A.; and Sen, A. In IEEE Texas Power and Energy Conference (TPEC), pages 1–6, College Station, TX, February 2018.
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@inproceedings{padhee_new_2018, address = {College Station, TX}, title = {A new model to analyze power system dependencies}, url = {https://ieeexplore.ieee.org/abstract/document/8312075}, abstract = {In a power systems context, dependency implies the reliance of certain system entities on the functioning of other system entities. Finding the appropriate level of abstraction for modeling power system dependency is a non-trivial task. This is true as a detailed study might be computationally intensive, while analysis done at a highly aggregated level might not provide very useful information. In this paper, a new model is proposed to analyze power system dependencies, which overcomes the limitations of existing models. A formal description of the model along with its working dynamics and a brief validation with respect to the 2011 Southwest Blackout are provided. The results indicate that this model is able to successfully capture the complex dependencies that exist in a modern power system.}, booktitle = {IEEE Texas Power and Energy Conference (TPEC)}, author = {Padhee, Malhar and Banerjee, Joydeep and Basu, Kaustav and Roy, Sohini and Pal, Anamitra and Sen, Arunabha}, month = feb, year = {2018}, keywords = {Cascading failure, Computational modeling, Generators, implicative interdependency model (IIM), Load flow, operational implicative interdependency model (OIIM), phasor measurement unit (PMU), Power grids, power system dependency, Power system stability, Power transmission lines}, pages = {1--6}, }
In a power systems context, dependency implies the reliance of certain system entities on the functioning of other system entities. Finding the appropriate level of abstraction for modeling power system dependency is a non-trivial task. This is true as a detailed study might be computationally intensive, while analysis done at a highly aggregated level might not provide very useful information. In this paper, a new model is proposed to analyze power system dependencies, which overcomes the limitations of existing models. A formal description of the model along with its working dynamics and a brief validation with respect to the 2011 Southwest Blackout are provided. The results indicate that this model is able to successfully capture the complex dependencies that exist in a modern power system.
Cascading effects of targeted attacks on the power grid. Meyur, R.; Vullikanti, A.; Marathe, M. V.; Pal, A.; Youssef, M.; and Centeno, V. Volume 812 . Complex Networks and Their Applications. Studies in Computational Intelligence, pages 155–167. Springer International Publishing, Cham, Dec 2018.
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@InBook{meyur_cascading_2018, chapter = {Cascading effects of targeted attacks on the power grid}, publisher = {Springer International Publishing}, title = {Complex Networks and Their Applications. Studies in Computational Intelligence}, address = {Cham}, pages = {155--167}, month = {Dec}, year = {2018}, author = {Meyur, Rounak and Vullikanti, Anil and Marathe, Madhav V. and Pal, Anamitra and Youssef, Mina and Centeno, Virgilio}, volume = {812}, }
Energy demand model for residential sector: A first principles approach. Subbiah, R.; Pal, A.; Nordberg, E. K.; Marathe, A.; and Marathe, M. V. IEEE Transactions on Sustainable Energy, 8(3): 1215–1224. July 2017.
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@article{subbiah_energy_2017, title = {Energy demand model for residential sector: A first principles approach}, volume = {8}, url = {https://ieeexplore.ieee.org/abstract/document/7857082}, abstract = {According to the U.S. Energy Information Administration (EIA), the residential sector accounts for one-third of the country's energy consumption. This number is steadily increasing, posing a challenge to energy regulators as well as suppliers. To manage the growing demand for energy, there is a need for energy system optimization, especially on the demand side. This paper uses a first principles approach to build a high-resolution energy demand model, which can be used as a test bed by academicians as well as policy makers for performing such optimizations. This framework generates activity-based, building-level, time-dependent demand profiles. The model associates appliance usage with each household activity and calculates energy consumption based on the appliance energy rating, the duration of the energy consuming activity, and the type of activity performed by each household member. It also accounts for shared activities among household members to avoid double counting. Additionally, passive energy consumptions such as space heating/cooling, lighting, etc., are measured. Finally, validation of the results obtained by this model against real-world data for Virginia is carried out. The results indicate that the modeling framework is robust and can be extended to other parts of the U.S. and beyond.}, number = {3}, journal = {IEEE Transactions on Sustainable Energy}, author = {Subbiah, Rajesh and Pal, Anamitra and Nordberg, Eric K. and Marathe, Achla and Marathe, Madhav V.}, month = jul, year = {2017}, keywords = {Activity-based, appliance usage, Data models, Energy consumption, energy demand, energy rating, Home appliances, residential, Schedules, shared activity, Sociology, Space heating, Statistics}, pages = {1215--1224}, }
According to the U.S. Energy Information Administration (EIA), the residential sector accounts for one-third of the country's energy consumption. This number is steadily increasing, posing a challenge to energy regulators as well as suppliers. To manage the growing demand for energy, there is a need for energy system optimization, especially on the demand side. This paper uses a first principles approach to build a high-resolution energy demand model, which can be used as a test bed by academicians as well as policy makers for performing such optimizations. This framework generates activity-based, building-level, time-dependent demand profiles. The model associates appliance usage with each household activity and calculates energy consumption based on the appliance energy rating, the duration of the energy consuming activity, and the type of activity performed by each household member. It also accounts for shared activities among household members to avoid double counting. Additionally, passive energy consumptions such as space heating/cooling, lighting, etc., are measured. Finally, validation of the results obtained by this model against real-world data for Virginia is carried out. The results indicate that the modeling framework is robust and can be extended to other parts of the U.S. and beyond.
Use of polytopic convexity in developing an adaptive inter-area oscillation damping scheme. Wang, T.; Pal, A.; Thorp, J. S.; and Yang, Y. IEEE Transactions on Power Systems, 32(4): 2509–2520. July 2017.
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@article{wang_use_2017, title = {Use of polytopic convexity in developing an adaptive inter-area oscillation damping scheme}, volume = {32}, url = {https://ieeexplore.ieee.org/abstract/document/7592414}, abstract = {An adaptive control scheme based on the convexity property of polytopes for damping interarea oscillations is developed here. A polytopic control guarantees requisite damping when the current operating point lies inside it. Multiple polytopes increase the robustness of the control provided the polytope inside which the operating point lies after a disturbance is correctly identified. In this paper, the identification of the correct polytope is performed using Kalman-filters and the mean-chi square variable. A 29-machine 127-bus model of the Western Electricity Coordinating Council (WECC) system is used as the test system for this analysis. The simulation results demonstrate that the proposed adaptive control is able to provide adequate damping to the interarea modes of oscillation under changing operating conditions without any prior knowledge of the postdisturbance operating state. It is also found to be more robust than some of the modern controllers proposed previously.}, number = {4}, journal = {IEEE Transactions on Power Systems}, author = {Wang, Tong and Pal, Anamitra and Thorp, James S. and Yang, Yuan}, month = jul, year = {2017}, keywords = {Adaptive control, Damping, inter-area oscillation, Kalman filter, Kalman filters, linear matrix inequality (LMI), mean chi-square variable, Oscillators, phasor measurement unit (PMU), polytopic convexity, Power system stability, Robustness, Uncertainty}, pages = {2509--2520}, }
An adaptive control scheme based on the convexity property of polytopes for damping interarea oscillations is developed here. A polytopic control guarantees requisite damping when the current operating point lies inside it. Multiple polytopes increase the robustness of the control provided the polytope inside which the operating point lies after a disturbance is correctly identified. In this paper, the identification of the correct polytope is performed using Kalman-filters and the mean-chi square variable. A 29-machine 127-bus model of the Western Electricity Coordinating Council (WECC) system is used as the test system for this analysis. The simulation results demonstrate that the proposed adaptive control is able to provide adequate damping to the interarea modes of oscillation under changing operating conditions without any prior knowledge of the postdisturbance operating state. It is also found to be more robust than some of the modern controllers proposed previously.
A PMU placement scheme considering realistic costs and modern trends in relaying. Pal, A.; Vullikanti, A. K. S.; and Ravi, S. S. IEEE Transactions on Power Systems, 32(1): 552–561. January 2017.
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@article{pal_pmu_2017, title = {A PMU placement scheme considering realistic costs and modern trends in relaying}, volume = {32}, url = {https://ieeexplore.ieee.org/abstract/document/7448960}, abstract = {Synchrophasor deployment costs have evolved over time. The cost of upgrading a substation, which is much larger than the cost of an individual device, has emerged as the primary constituent of the total expenditure. Given these circumstances, the optimal phasor measurement unit placement formulation needs to consider not only the number of devices that must be placed at the substations, but also the number of substations that must be upgraded to support those devices. This paper presents an integer linear programming methodology for such a placement scheme while considering realistic costs and practical constraints. The IEEE 30 bus system is used to illustrate the proposed concept, while the IEEE 118, IEEE 300, and Polish 2383 bus systems are used to show the performance of the method under different test environments.}, number = {1}, journal = {IEEE Transactions on Power Systems}, author = {Pal, Anamitra and Vullikanti, Anil Kumar S. and Ravi, S. S.}, month = jan, year = {2017}, keywords = {Critical-bus concept, dual-use line relay (DULR), integer linear programming (ILP), Monitoring, N–t contingency, observability, Observability, optimal cost, phasor measurement unit (PMU), Phasor measurement units, State estimation, Substations, Transmission line measurements, Voltage measurement}, pages = {552--561}, }
Synchrophasor deployment costs have evolved over time. The cost of upgrading a substation, which is much larger than the cost of an individual device, has emerged as the primary constituent of the total expenditure. Given these circumstances, the optimal phasor measurement unit placement formulation needs to consider not only the number of devices that must be placed at the substations, but also the number of substations that must be upgraded to support those devices. This paper presents an integer linear programming methodology for such a placement scheme while considering realistic costs and practical constraints. The IEEE 30 bus system is used to illustrate the proposed concept, while the IEEE 118, IEEE 300, and Polish 2383 bus systems are used to show the performance of the method under different test environments.
General optimal substation coverage algorithm for phasor measurement unit placement in practical systems. Pal, A.; Mishra, C.; Vullikanti, A. K. S.; and Ravi, S. S. IET Gener., Transm. Distrib., 11(2): 347–353. January 2017.
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@article{pal_general_2017, title = {General optimal substation coverage algorithm for phasor measurement unit placement in practical systems}, volume = {11}, url = {https://digital-library.theiet.org/content/journals/10.1049/iet-gtd.2016.0553}, abstract = {The primary objective of the conventional optimal phasor measurement unit (PMU) placement problem is the minimisation of the number of PMU devices that, when placed in a power system, measure all bus voltages. However, due to advancements in the field of relay technology, digital relays can now act as PMUs. This has significantly reduced device costs. Moreover, although the goal is to observe all the buses, the devices themselves can only be placed in substations, whose upgrade costs are much higher than those of the devices. Considering these factors, the approach proposed here simultaneously optimises the number of substations where traditional PMUs and dual-use line relay PMUs can be placed. The general optimal substation coverage (GOSC) algorithm presented in this study is also able to incorporate practical requirements such as redundancy in the measurement of critical elements of the system, and estimation of the tap ratios of the transformers present. Simulation results indicate that the GOSC algorithm provides significant techno-economic benefits.}, number = {2}, journal = {IET Gener., Transm. Distrib.}, author = {Pal, Anamitra and Mishra, Chetan and Vullikanti, Anil Kumar S. and Ravi, S. S.}, month = jan, year = {2017}, pages = {347--353}, }
The primary objective of the conventional optimal phasor measurement unit (PMU) placement problem is the minimisation of the number of PMU devices that, when placed in a power system, measure all bus voltages. However, due to advancements in the field of relay technology, digital relays can now act as PMUs. This has significantly reduced device costs. Moreover, although the goal is to observe all the buses, the devices themselves can only be placed in substations, whose upgrade costs are much higher than those of the devices. Considering these factors, the approach proposed here simultaneously optimises the number of substations where traditional PMUs and dual-use line relay PMUs can be placed. The general optimal substation coverage (GOSC) algorithm presented in this study is also able to incorporate practical requirements such as redundancy in the measurement of critical elements of the system, and estimation of the tap ratios of the transformers present. Simulation results indicate that the GOSC algorithm provides significant techno-economic benefits.
Analyzing effects of seasonal variations in wind generation and load on voltage profiles. Padhee, M.; Pal, A.; and Vance, K. A. In North American Power Symposium (NAPS), pages 1–6, Morgantown, WV, September 2017.
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@inproceedings{padhee_analyzing_2017, address = {Morgantown, WV}, title = {Analyzing effects of seasonal variations in wind generation and load on voltage profiles}, url = {https://ieeexplore.ieee.org/abstract/document/8107344}, abstract = {This paper presents a methodology for building daily profiles of wind generation and load for different seasons to assess their impacts on voltage violations. The measurement-based wind models showed very high accuracy when validated against several years of actual wind power data. System load modeling was carried out by analyzing the seasonal trends that occur in residential, commercial, and industrial loads. When the proposed approach was implemented on the IEEE 118-bus system, it could identify violations in bus voltage profiles that the season-independent model could not capture. The results of the proposed approach are expected to provide better visualization of the problems that seasonal variations in wind power and load might cause to the electric power grid.}, booktitle = {North American Power Symposium (NAPS)}, author = {Padhee, Malhar and Pal, Anamitra and Vance, Katelynn A.}, month = sep, year = {2017}, keywords = {Data models, Load modeling, Power measurement, power system measurements, Power system stability, seasonal variation, Springs, voltage violation, wind energy, Wind power generation, Wind speed}, pages = {1--6}, }
This paper presents a methodology for building daily profiles of wind generation and load for different seasons to assess their impacts on voltage violations. The measurement-based wind models showed very high accuracy when validated against several years of actual wind power data. System load modeling was carried out by analyzing the seasonal trends that occur in residential, commercial, and industrial loads. When the proposed approach was implemented on the IEEE 118-bus system, it could identify violations in bus voltage profiles that the season-independent model could not capture. The results of the proposed approach are expected to provide better visualization of the problems that seasonal variations in wind power and load might cause to the electric power grid.
Controller tuning of generic positive sequence solar PV models used in interconnection studies. Chakraborty, T.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Morgantown, WV, September 2017.
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@inproceedings{chakraborty_controller_2017, address = {Morgantown, WV}, title = {Controller tuning of generic positive sequence solar {PV} models used in interconnection studies}, url = {https://ieeexplore.ieee.org/abstract/document/8107375}, abstract = {With increased penetration of renewable energy sources in the bulk electricity system, it is important for power system planners and operators to maintain grid stability and carry out system impact studies for identifying reliability-related problems. Adequate models have been developed by the industry to represent positive sequence response of solar PV plants for grid interconnection studies. In this work, both steady state and dynamic modeling of interconnected solar plants are discussed. Test systems are developed in positive sequence power system simulators such as Siemens PSS/E and GE PSLF to capture inverter models' response to various control modes. The results of this work provide a better visualization of how tuning the gains of the electrical control and the power plant control can stabilize solar plant operations in an interconnected network.}, booktitle = {North American Power Symposium (NAPS)}, author = {Chakraborty, Tamojit and Pal, Anamitra}, month = sep, year = {2017}, keywords = {Control systems, Generators, Interconnection Studies, Inverters, Positive Sequence Simulation Models, Power generation, Reactive power, Solar PV Plants, Steady-state, Voltage control}, pages = {1--6}, }
With increased penetration of renewable energy sources in the bulk electricity system, it is important for power system planners and operators to maintain grid stability and carry out system impact studies for identifying reliability-related problems. Adequate models have been developed by the industry to represent positive sequence response of solar PV plants for grid interconnection studies. In this work, both steady state and dynamic modeling of interconnected solar plants are discussed. Test systems are developed in positive sequence power system simulators such as Siemens PSS/E and GE PSLF to capture inverter models' response to various control modes. The results of this work provide a better visualization of how tuning the gains of the electrical control and the power plant control can stabilize solar plant operations in an interconnected network.
Stability region estimation under low voltage ride through constraints using sum of squares. Mishra, C.; Thorp, J. S.; Centeno, V. A.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Morgantown, WV, September 2017.
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@inproceedings{mishra_stability_2017, address = {Morgantown, WV}, title = {Stability region estimation under low voltage ride through constraints using sum of squares}, url = {https://ieeexplore.ieee.org/abstract/document/8107353}, abstract = {The increasing penetration of inverter based renewable generation (RG) in the form of solar photo-voltaic (PV) or wind has introduced numerous operational challenges and uncertainties. According to the standards [1], [2], these generators are made to trip offline if their operating requirements are not met. In an RG-rich system, this might alter the system dynamics and/or cause shifting of the equilibrium points to the extent that a cascaded tripping scenario is manifested. The present work attempts at avoiding such scenarios by estimating the constrained stability region (CSR) inside which the system must operate using maximal level set of a Lyapunov function estimated through sum of squares (SOS) technique. A time-independent conservative approximation of the LVRT constraint is initially derived for a classical model of the power system. The proposed approach is eventually validated by evaluating the stability of a 3 machine test system with trip-able RG.}, booktitle = {North American Power Symposium (NAPS)}, author = {Mishra, Chetan and Thorp, James S. and Centeno, Virgilio A. and Pal, Anamitra}, month = sep, year = {2017}, keywords = {Constrained stability region (CSR), direct methods, Generators, Inverters, low voltage ride through (L VRT), Lyapunov methods, Mathematical model, Power system stability, Stability criteria, sum of squares (SOS)}, pages = {1--6}, }
The increasing penetration of inverter based renewable generation (RG) in the form of solar photo-voltaic (PV) or wind has introduced numerous operational challenges and uncertainties. According to the standards [1], [2], these generators are made to trip offline if their operating requirements are not met. In an RG-rich system, this might alter the system dynamics and/or cause shifting of the equilibrium points to the extent that a cascaded tripping scenario is manifested. The present work attempts at avoiding such scenarios by estimating the constrained stability region (CSR) inside which the system must operate using maximal level set of a Lyapunov function estimated through sum of squares (SOS) technique. A time-independent conservative approximation of the LVRT constraint is initially derived for a classical model of the power system. The proposed approach is eventually validated by evaluating the stability of a 3 machine test system with trip-able RG.
Challenges and trade-offs of a cloud hosted phasor measurement unit-based linear state estimator. Chakati, V.; Pore, M.; Pal, A.; Banerjee, A.; and Gupta, S. K. S. In IEEE Power Energy Society Conference on Innovative Smart Grid Technologies (ISGT), pages 1–5, Washington, DC, April 2017.
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@inproceedings{chakati_challenges_2017, address = {Washington, DC}, title = {Challenges and trade-offs of a cloud hosted phasor measurement unit-based linear state estimator}, url = {https://ieeexplore.ieee.org/abstract/document/8085957}, abstract = {Being one of the key derivatives of phasor measurement units (PMUs), a synchrophasor-only linear state estimator (LSE) presents a reliable, high quality, and truly dynamic picture of the power grid. However, with the increase in number of buses monitored by PMUs, computational burden will become a critical constraint for the state estimation solver. Although installing additional hardware can be a possible solution, such a solution will considerably raise the cost of capital investment, operation, and maintenance. This paper proposes cloud-computing as a cost-effective alternative to the computational burden problem. This paper also presents feasibility of the cloud based solution with regards to scalability of the system and latency incurred. Our solution is designed to address the critical operational parameters such as latency and variable network sizes. Additionally, the LSE application establishes robust communication procedures to process inputs arriving at high data rates from multiple PMUs. The paper concludes by highlighting future research directions for enhancing such cloud based solutions.}, booktitle = {IEEE Power Energy Society Conference on Innovative Smart Grid Technologies (ISGT)}, author = {Chakati, Vinaya and Pore, Madhurima and Pal, Anamitra and Banerjee, Ayan and Gupta, Sandeep K. S.}, month = apr, year = {2017}, keywords = {Current measurement, Phasor measurement units, Real-time systems, Servers, State estimation, Transmission line matrix methods, Voltage measurement}, pages = {1--5}, }
Being one of the key derivatives of phasor measurement units (PMUs), a synchrophasor-only linear state estimator (LSE) presents a reliable, high quality, and truly dynamic picture of the power grid. However, with the increase in number of buses monitored by PMUs, computational burden will become a critical constraint for the state estimation solver. Although installing additional hardware can be a possible solution, such a solution will considerably raise the cost of capital investment, operation, and maintenance. This paper proposes cloud-computing as a cost-effective alternative to the computational burden problem. This paper also presents feasibility of the cloud based solution with regards to scalability of the system and latency incurred. Our solution is designed to address the critical operational parameters such as latency and variable network sizes. Additionally, the LSE application establishes robust communication procedures to process inputs arriving at high data rates from multiple PMUs. The paper concludes by highlighting future research directions for enhancing such cloud based solutions.
A robust techno-economic analysis of PMU-based islanding detection schemes. Biswas, R. S.; and Pal, A. In IEEE Texas Power and Energy Conference (TPEC), pages 1–6, College Station, TX, February 2017.
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@inproceedings{biswas_robust_2017, address = {College Station, TX}, title = {A robust techno-economic analysis of PMU-based islanding detection schemes}, url = {https://ieeexplore.ieee.org/abstract/document/7868290}, abstract = {Traditional islanding detection schemes have mainly relied on voltage angle measurements obtained from PMUs for determining island formation. However, when placed in a network, PMUs measure both voltages and currents. In this paper, we test the hypothesis that better results can be obtained if other quantities measured by a PMU are also considered for islanding detection. Prior research considered device minimization as the primary objective for placing PMUs. An alternate formulation of the PMU placement problem that minimized total synchrophasor deployment cost has also been proposed recently. The second hypothesis that we test is if accuracies similar to what was observed with the device minimization objective are attained with the alternate formulation. Our results indicate that from a techno-economic perspective, better performance is realized if all the information provided by PMUs is used for decision making with the PMU locations computed using the alternate formulation.}, booktitle = {IEEE Texas Power and Energy Conference (TPEC)}, author = {Biswas, Reetam Sen and Pal, Anamitra}, month = feb, year = {2017}, keywords = {Clustering algorithms, Current measurement, Device minimization, islanding, Minimization, optimal PMU placement (OPP), Optimization, Phasor measurement units, substation optimization, Substations, techno-economic analysis, Voltage measurement}, pages = {1--6}, }
Traditional islanding detection schemes have mainly relied on voltage angle measurements obtained from PMUs for determining island formation. However, when placed in a network, PMUs measure both voltages and currents. In this paper, we test the hypothesis that better results can be obtained if other quantities measured by a PMU are also considered for islanding detection. Prior research considered device minimization as the primary objective for placing PMUs. An alternate formulation of the PMU placement problem that minimized total synchrophasor deployment cost has also been proposed recently. The second hypothesis that we test is if accuracies similar to what was observed with the device minimization objective are attained with the alternate formulation. Our results indicate that from a techno-economic perspective, better performance is realized if all the information provided by PMUs is used for decision making with the PMU locations computed using the alternate formulation.
Phasor Measurement-Enabled Decision Making. Pal, A. Synchronized Phasor Measurements and Their Applications: Phasor Measurement-Enabled Decision Making, pages 211–243. Springer International Publishing, Jan 2017.
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@InBook{pal_synchronized_chapter_2017, author = {Pal, Anamitra}, title = {Synchronized Phasor Measurements and Their Applications: Phasor Measurement-Enabled Decision Making}, chapter = {Phasor Measurement-Enabled Decision Making}, pages = {211--243}, publisher = {Springer International Publishing}, month = {Jan}, year = {2017} }
A community-based partitioning approach for phasor measurement unit placement in large systems. Pal, A.; Sanchez-Ayala, G. A.; Thorp, J. S.; and Centeno, V. A. Electric Power Components and Systems, 44(12): 1317–1329. June 2016.
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@article{pal_community-based_2016, title = {A community-based partitioning approach for phasor measurement unit placement in large systems}, volume = {44}, url = {https://www.tandfonline.com/doi/abs/10.1080/15325008.2016.1167791}, abstract = {A phasor measurement unit placement scheme is developed in this article that ensures complete observability of large systems while reducing the computational burden of optimization. Redundancy in measurement of the critical buses of the network that are identified based on system studies and/or topologies is also provided by the proposed methodology. The community-based islanding approach initially partitions the system into smaller islands. Placement of phasor measurement units in these islands is then computed using integer linear programming. A bound is also developed to find the maximum error from a global optimal solution. The proposed technique is applied to standard IEEE systems as well as on more realistic power system networks. The results indicate that the proposed technique optimizes the benefits of having phasor measurement units at strategic locations of a large power system network without the associated computational burdens.}, number = {12}, journal = {Electric Power Components and Systems}, author = {Pal, Anamitra and Sanchez-Ayala, Gerardo A. and Thorp, James S. and Centeno, Virgilio A.}, month = jun, year = {2016}, keywords = {community-based islanding, integer linear programming, large systems, observability, phasor measurement unit, redundancy}, pages = {1317--1329}, }
A phasor measurement unit placement scheme is developed in this article that ensures complete observability of large systems while reducing the computational burden of optimization. Redundancy in measurement of the critical buses of the network that are identified based on system studies and/or topologies is also provided by the proposed methodology. The community-based islanding approach initially partitions the system into smaller islands. Placement of phasor measurement units in these islands is then computed using integer linear programming. A bound is also developed to find the maximum error from a global optimal solution. The proposed technique is applied to standard IEEE systems as well as on more realistic power system networks. The results indicate that the proposed technique optimizes the benefits of having phasor measurement units at strategic locations of a large power system network without the associated computational burdens.
Binary particle swarm optimisation-based optimal substation coverage algorithm for phasor measurement unit installations in practical systems. Mishra, C.; Jones, K. D.; Pal, A.; and Centeno, V. A. IET Generation, Transmission & Distribution, 10(2): 555–562. February 2016.
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@article{mishra_binary_2016, title = {Binary particle swarm optimisation-based optimal substation coverage algorithm for phasor measurement unit installations in practical systems}, volume = {10}, url = {https://digital-library.theiet.org/content/journals/10.1049/iet-gtd.2015.1077}, abstract = {Phasor measurement units (PMUs) play an important role in the wide-area monitoring and protection of modern power systems. Historically, their deployment was limited by the prohibitive cost of the device itself. Therefore, the objective of the conventional optimal PMU placement problem was to find minimum number of devices, which when carefully placed throughout the network, maximised observability subject to different constraints. Due to improvements in relay technology, digital relays can now serve as both relays and PMUs. Under such circumstances, the substation installations consume the largest portion of the deployment cost, and not the devices themselves. Thus, for minimising cost of synchrophasor deployment, number of substation installations must be minimised. This study uses binary particle swarm optimisation to minimise number of substations in which installations must be performed for making all voltage levels observable, while being subject to various practical constraints. Standard IEEE systems have been used to explain the technique. Finally, a large-scale network of Dominion Virginia Power is used as the test bed for implementation.}, number = {2}, journal = {IET Generation, Transmission \& Distribution}, author = {Mishra, Chetan and Jones, Kevin D. and Pal, Anamitra and Centeno, Virgilio A.}, month = feb, year = {2016}, pages = {555--562}, }
Phasor measurement units (PMUs) play an important role in the wide-area monitoring and protection of modern power systems. Historically, their deployment was limited by the prohibitive cost of the device itself. Therefore, the objective of the conventional optimal PMU placement problem was to find minimum number of devices, which when carefully placed throughout the network, maximised observability subject to different constraints. Due to improvements in relay technology, digital relays can now serve as both relays and PMUs. Under such circumstances, the substation installations consume the largest portion of the deployment cost, and not the devices themselves. Thus, for minimising cost of synchrophasor deployment, number of substation installations must be minimised. This study uses binary particle swarm optimisation to minimise number of substations in which installations must be performed for making all voltage levels observable, while being subject to various practical constraints. Standard IEEE systems have been used to explain the technique. Finally, a large-scale network of Dominion Virginia Power is used as the test bed for implementation.
Online calibration of voltage transformers using synchrophasor measurements. Pal, A.; Chatterjee, P.; Thorp, J. S.; and Centeno, V. A. IEEE Trans. on Power Del., 31(1): 370–380. February 2016.
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@article{pal_online_2016, title = {Online calibration of voltage transformers using synchrophasor measurements}, volume = {31}, url = {https://ieeexplore.ieee.org/abstract/document/7307200}, abstract = {Uncalibrated instrument transformers present at the inputs of phasor measurement units (PMUs) can significantly degrade their outputs. This also causes problems in downstream applications that use PMU data. This paper presents a method for calibrating voltage transformers online using synchrophasor measurements. The proposed approach aims to find the optimal locations where good quality measurements must be added in order to bring the calibration error of all the measurements below a predefined threshold. The IEEE 118-bus system, the IEEE 300-bus system, and a 2383-bus Polish system have been used as the test systems for this analysis. The advantage of the proposed approach is its effectiveness and robustness.}, number = {1}, journal = {IEEE Trans. on Power Del.}, author = {Pal, Anamitra and Chatterjee, Paroma and Thorp, James S. and Centeno, Virgilio A.}, month = feb, year = {2016}, keywords = {Binary integer programming (BIP), calibration, Calibration, Current measurement, Instrument transformers, Mathematical model, Measurement uncertainty, optimal placement, Phasor measurement units, phasor measurement units (PMUs), Voltage measurement, voltage transformers}, pages = {370--380}, }
Uncalibrated instrument transformers present at the inputs of phasor measurement units (PMUs) can significantly degrade their outputs. This also causes problems in downstream applications that use PMU data. This paper presents a method for calibrating voltage transformers online using synchrophasor measurements. The proposed approach aims to find the optimal locations where good quality measurements must be added in order to bring the calibration error of all the measurements below a predefined threshold. The IEEE 118-bus system, the IEEE 300-bus system, and a 2383-bus Polish system have been used as the test systems for this analysis. The advantage of the proposed approach is its effectiveness and robustness.
Impact of a Surface Nuclear Blast on the Transient Stability of the Power System. Barrett, C. L.; Centeno, V.; Eubank, S.; Yaman Evrenosoglu, C.; Marathe, A.; Marathe, M. V.; Mishra, C.; Mortveit, H.; Pal, A.; Phadke, A.; Thorp, J.; Vullikanti, A.; and Youssef, M. pages 153–158. Panayiotou, C. G.; Ellinas, G.; Kyriakides, E.; and Polycarpou, M. M., editor(s). Springer International Publishing, Cham, 2016.
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@InBook{barrett_impact_2016, address = {Cham}, chapter = {Impact of a {Surface} {Nuclear} {Blast} on the {Transient} {Stability} of the {Power} {System}}, url = {https://link.springer.com/chapter/10.1007/978-3-319-31664-2_16}, abstract = {In this chapter, we study the consequences of an improvised nuclear detonation (IND) to the sub-transmission and distribution systems of Washington D.C. in the Eastern Interconnection (EI). We briefly discuss the geographical location of the blast and the interconnection of the power utility serving this area, with the neighboring power utilities. Analysis of the grid with respect to steady state stability as well as transient stability is performed to understand the impact of loss in load as a result of the blast. The steady state analysis alone does not offer a complete understanding of the loss of the neighboring substations. The transient stability analysis shows that for the simulated event, the system stabilizes approximately 7 s after the occurrence of the event. The stability of the system can be attributed to the fact that the drop in load was relatively small compared to the generation capacity of the EI.}, booktitle = {{CRITIS} 2014: {Critical} {Information} {Infrastructures} {Security}}, publisher = {Springer International Publishing}, author = {Barrett, Christopher L. and Centeno, Virgilio and Eubank, Stephen and Yaman Evrenosoglu, Cansin and Marathe, Achla and Marathe, Madhav V. and Mishra, Chetan and Mortveit, Henning and Pal, Anamitra and Phadke, Arun and Thorp, James and Vullikanti, Anil and Youssef, Mina}, editor = {Panayiotou, Christos G. and Ellinas, Georgios and Kyriakides, Elias and Polycarpou, Marios M.}, year = {2016}, keywords = {Eastern interconnection, Improvised nuclear detonation, Stability analysis}, pages = {153--158}, }
In this chapter, we study the consequences of an improvised nuclear detonation (IND) to the sub-transmission and distribution systems of Washington D.C. in the Eastern Interconnection (EI). We briefly discuss the geographical location of the blast and the interconnection of the power utility serving this area, with the neighboring power utilities. Analysis of the grid with respect to steady state stability as well as transient stability is performed to understand the impact of loss in load as a result of the blast. The steady state analysis alone does not offer a complete understanding of the loss of the neighboring substations. The transient stability analysis shows that for the simulated event, the system stabilizes approximately 7 s after the occurrence of the event. The stability of the system can be attributed to the fact that the drop in load was relatively small compared to the generation capacity of the EI.
Multi-polytope-based adaptive robust damping control in power systems using CART. Wang, T.; Pal, A.; Thorp, J. S.; Wang, Z.; Liu, J.; and Yang, Y. IEEE Trans. on Power Systems, 30(4): 2063–2072. July 2015.
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@article{wang_multi-polytope-based_2015, title = {Multi-polytope-based adaptive robust damping control in power systems using CART}, volume = {30}, url = {https://ieeexplore.ieee.org/abstract/document/6902835}, abstract = {An adaptive damping control scheme based on classification and regression tree (CART) using wide-area signals is proposed in this paper. Different polytopes are chosen using classification trees. Next, a family of robust polytopic controllers is designed off-line. Finally, using regression trees and PMU data, the desired polytopic controller is identified in real time. A 16-generator, 68-bus system is used as the test system. Remote signals obtained from PMUs are employed for control purposes. The simulation results demonstrate that the proposed adaptive control scheme is able to provide adequate damping for the oscillation modes of interest with respect to varying operating conditions without any prior knowledge of the post-disturbance state.}, number = {4}, journal = {IEEE Trans. on Power Systems}, author = {Wang, Tong and Pal, Anamitra and Thorp, James S. and Wang, Zengping and Liu, Jizhen and Yang, Yuan}, month = jul, year = {2015}, keywords = {Adaptive control, Adaptive damping control, classification and regression tree (CART), Current measurement, Damping, inter-area oscillations, linear matrix inequalities (LMIs), Oscillators, polytopic control, Power system stability, Robust control, Robustness, wide-area measurements}, pages = {2063--2072}, }
An adaptive damping control scheme based on classification and regression tree (CART) using wide-area signals is proposed in this paper. Different polytopes are chosen using classification trees. Next, a family of robust polytopic controllers is designed off-line. Finally, using regression trees and PMU data, the desired polytopic controller is identified in real time. A 16-generator, 68-bus system is used as the test system. Remote signals obtained from PMUs are employed for control purposes. The simulation results demonstrate that the proposed adaptive control scheme is able to provide adequate damping for the oscillation modes of interest with respect to varying operating conditions without any prior knowledge of the post-disturbance state.
Methodology for performing synchrophasor data conditioning and validation. Jones, K. D.; Pal, A.; and Thorp, J. S. IEEE Transactions on Power Systems, 30(3): 1121–1130. May 2015.
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@article{jones_methodology_2015,
title = {Methodology for performing synchrophasor data conditioning and validation},
volume = {30},
url = {https://ieeexplore.ieee.org/abstract/document/6889046},
abstract = {A phasor measurement unit (PMU) only state estimator is intrinsically superior to its SCADA analogue with respect to speed, performance, and reliability. However, ensuring the quality of the data stream which enters the linear estimator is crucial before establishing it as the front end of an EMS or other network applications. One approach is to pre-process the phasor data before it arrives at the linear estimator. This paper presents an algorithm for synchrophasor data conditioning and repair that fits neatly as a prefix into the existing linear state estimation formulation. The methodology has been tested using field data obtained from PMUs installed in Dominion Virginia Power's (DVP's) EHV network. The results indicate that the proposed technique provides a computationally simple, elegant solution to the synchrophasor data quality problem.},
number = {3},
journal = {IEEE Transactions on Power Systems},
author = {Jones, Kevin D. and Pal, Anamitra and Thorp, James S.},
month = may,
year = {2015},
keywords = {Current measurement, Data models, Data quality, Kalman filter, Kalman filters, Mathematical model, phasor measurement unit (PMU), Phasor measurement units, Prediction algorithms, Smoothing methods, state estimation},
pages = {1121--1130},
}
A phasor measurement unit (PMU) only state estimator is intrinsically superior to its SCADA analogue with respect to speed, performance, and reliability. However, ensuring the quality of the data stream which enters the linear estimator is crucial before establishing it as the front end of an EMS or other network applications. One approach is to pre-process the phasor data before it arrives at the linear estimator. This paper presents an algorithm for synchrophasor data conditioning and repair that fits neatly as a prefix into the existing linear state estimation formulation. The methodology has been tested using field data obtained from PMUs installed in Dominion Virginia Power's (DVP's) EHV network. The results indicate that the proposed technique provides a computationally simple, elegant solution to the synchrophasor data quality problem.
A voltage phasor based fault classification method for phasor measurement unit only state estimator output. Gao, F.; Thorp, J. S.; Gao, S.; Pal, A.; and Vance, K. A. Elect. Power Compon. Syst., 43(1): 22–31. January 2015.
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@article{jones_methodology_2015, title = {Methodology for performing synchrophasor data conditioning and validation}, volume = {30}, url = {https://ieeexplore.ieee.org/abstract/document/6889046}, abstract = {A phasor measurement unit (PMU) only state estimator is intrinsically superior to its SCADA analogue with respect to speed, performance, and reliability. However, ensuring the quality of the data stream which enters the linear estimator is crucial before establishing it as the front end of an EMS or other network applications. One approach is to pre-process the phasor data before it arrives at the linear estimator. This paper presents an algorithm for synchrophasor data conditioning and repair that fits neatly as a prefix into the existing linear state estimation formulation. The methodology has been tested using field data obtained from PMUs installed in Dominion Virginia Power's (DVP's) EHV network. The results indicate that the proposed technique provides a computationally simple, elegant solution to the synchrophasor data quality problem.}, number = {3}, journal = {IEEE Transactions on Power Systems}, author = {Jones, Kevin D. and Pal, Anamitra and Thorp, James S.}, month = may, year = {2015}, keywords = {Current measurement, Data models, Data quality, Kalman filter, Kalman filters, Mathematical model, phasor measurement unit (PMU), Phasor measurement units, Prediction algorithms, Smoothing methods, state estimation}, pages = {1121--1130}, }
A phasor measurement unit (PMU) only state estimator is intrinsically superior to its SCADA analogue with respect to speed, performance, and reliability. However, ensuring the quality of the data stream which enters the linear estimator is crucial before establishing it as the front end of an EMS or other network applications. One approach is to pre-process the phasor data before it arrives at the linear estimator. This paper presents an algorithm for synchrophasor data conditioning and repair that fits neatly as a prefix into the existing linear state estimation formulation. The methodology has been tested using field data obtained from PMUs installed in Dominion Virginia Power's (DVP's) EHV network. The results indicate that the proposed technique provides a computationally simple, elegant solution to the synchrophasor data quality problem.
Unified PMU placement algorithm for power systems. Amare, K.; Centeno, V. A.; and Pal, A. In North American Power Symposium (NAPS), pages 1–6, Charlotte, NC, October 2015.
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@article{gao_voltage_2015, title = {A voltage phasor based fault classification method for phasor measurement unit only state estimator output}, volume = {43}, url = {https://www.tandfonline.com/doi/abs/10.1080/15325008.2014.956951}, abstract = {”This article presents a fault-classification method for transmission lines based on voltage phasors using classification and regression trees. The proposed method is intended to aid system operators in understanding the outputs of a phasor measurement unit only state estimator. Faults are classified into four categories when the estimator is positive sequence and into ten categories when the estimator is three phase. The fault data are generated in PowerWorld® (PowerWorld Corporation, Champaign, IL, USA) and DSA Tools® (Powertech Labs Inc., Surrey, British Columbia, Canada). The pre-fault state consists of a variety of operating conditions and loading angles of faulted lines. The fault condition comprises different fault types, fault locations, fault impedances, and fault incidence angles. Fault classification is done using MATLAB® (The MathWorks, Natick, Massachusetts, USA).The approach is successfully tested on the IEEE-118 bus system. The results demonstrate that the technique developed here is effective and robust, irrespective of the pre-fault and fault conditions.}, number = {1}, journal = {Elect. Power Compon. Syst.}, author = {Gao, Fenghua and Thorp, James S. and Gao, Shibin and Pal, Anamitra and Vance, Katelynn A.}, month = jan, year = {2015}, keywords = {classification and regression tree, fault classification, fault type, fault voltage, phasor measurement units, state estimation, voltage phasors}, pages = {22--31}, }
”This article presents a fault-classification method for transmission lines based on voltage phasors using classification and regression trees. The proposed method is intended to aid system operators in understanding the outputs of a phasor measurement unit only state estimator. Faults are classified into four categories when the estimator is positive sequence and into ten categories when the estimator is three phase. The fault data are generated in PowerWorld® (PowerWorld Corporation, Champaign, IL, USA) and DSA Tools® (Powertech Labs Inc., Surrey, British Columbia, Canada). The pre-fault state consists of a variety of operating conditions and loading angles of faulted lines. The fault condition comprises different fault types, fault locations, fault impedances, and fault incidence angles. Fault classification is done using MATLAB® (The MathWorks, Natick, Massachusetts, USA).The approach is successfully tested on the IEEE-118 bus system. The results demonstrate that the technique developed here is effective and robust, irrespective of the pre-fault and fault conditions.
Kalman-filter based recursive regression for three-phase line parameter estimation using synchrophasor measurements. Mishra, C.; Centeno, V. A.; and Pal, A. In IEEE Power Energy Society General Meeting, pages 1–5, Denver, CO, July 2015.
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@inproceedings{amare_unified_2015, address = {Charlotte, NC}, title = {Unified PMU placement algorithm for power systems}, url = {https://ieeexplore.ieee.org/abstract/document/7335254}, abstract = {This paper presents a PMU (phasor measurement unit) placement algorithm that gives the optimal PMU placement location and minimum number of PMUs for any electric network while considering different approaches. Complete observability, complete observability with N - 1 redundancy, different depths of unobservability, multi-stage sequential placement, real-time monitoring of critical buses are the various PMU placement approaches considered in this paper. The required input for the proposed algorithm is system information and other key aspects like locations of existing PMUs, locations unsuitable for PMU placement, and knowledge of critical buses. Binary integer programming is used to find the respective PMU placement location and minimum number of PMUs. The algorithm is tested on IEEE 39-bus system, IEEE 118-bus system, and IEEE 300-bus system. The results suggest that the algorithm can be used on any power system network and the suitable PMU placement approach can be implemented for application.}, booktitle = {North American Power Symposium (NAPS)}, author = {Amare, Kunal and Centeno, Virgilio A. and Pal, Anamitra}, month = oct, year = {2015}, keywords = {Binary integer programming, Linear programming, Mathematical model, Monitoring, observability, Observability, optimal placement, Phasor measurement units, phasor measurement units (PMUs), Power system stability, Redundancy}, pages = {1--6}, }
This paper presents a PMU (phasor measurement unit) placement algorithm that gives the optimal PMU placement location and minimum number of PMUs for any electric network while considering different approaches. Complete observability, complete observability with N - 1 redundancy, different depths of unobservability, multi-stage sequential placement, real-time monitoring of critical buses are the various PMU placement approaches considered in this paper. The required input for the proposed algorithm is system information and other key aspects like locations of existing PMUs, locations unsuitable for PMU placement, and knowledge of critical buses. Binary integer programming is used to find the respective PMU placement location and minimum number of PMUs. The algorithm is tested on IEEE 39-bus system, IEEE 118-bus system, and IEEE 300-bus system. The results suggest that the algorithm can be used on any power system network and the suitable PMU placement approach can be implemented for application.
Role of power system relays in a large scale physical attack. Pal, A.; Youssef, M.; Vullikanti, A.; Marathe, A.; Eubank, S.; Marathe, M.; Barrett, C.; Thorp, J.; Phadke, A.; and Centeno, V. In 6th International Conference on Liberalization and Modernization of Power Systems and CRIS Problems of Critical Infrastructures, St. Petersburg, Russia, June 2015.
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@inproceedings{mishra_kalman-filter_2015, address = {Denver, CO}, title = {Kalman-filter based recursive regression for three-phase line parameter estimation using synchrophasor measurements}, url = {https://ieeexplore.ieee.org/abstract/document/7285678}, abstract = {In this paper estimation of three-phase transmission line parameters is done with the help of synchrophasor measurements by using a recursive regression technique based on the Kalman filter. The errors in the regression vector due to presence of noise in the synchrophasor data are also accounted for while estimating the parameters. The performance of this technique is demonstrated for a medium length transmission line. The results indicate that the proposed approach is able to successfully compute three phase transmission line parameters of non-transposed, non-symmetric lines.}, booktitle = {IEEE Power Energy Society General Meeting}, author = {Mishra, Chetan and Centeno, Virgilio A. and Pal, Anamitra}, month = jul, year = {2015}, keywords = {Estimation, Kalman filter, Measurement uncertainty, Noise measurement, Phasor measurement units, Phasor measurement units (PMUs), Power transmission lines, Recursive regression, Synchrophasors, Transmission line matrix methods, Transmission line measurements, Transmission line parameter estimation}, pages = {1--5}, }
In this paper estimation of three-phase transmission line parameters is done with the help of synchrophasor measurements by using a recursive regression technique based on the Kalman filter. The errors in the regression vector due to presence of noise in the synchrophasor data are also accounted for while estimating the parameters. The performance of this technique is demonstrated for a medium length transmission line. The results indicate that the proposed approach is able to successfully compute three phase transmission line parameters of non-transposed, non-symmetric lines.
Effect of different load models on the three-sample based quadratic prediction algorithm. Pal, A. In IEEE Power Energy Society Innovative Smart Grid Technologies Conference (ISGT), pages 1–5, Washington, DC, February 2015.
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@inproceedings{pal_role_2015, address = {St. Petersburg, Russia}, title = {Role of power system relays in a large scale physical attack}, url = {https://www.researchgate.net/publication/305432387_Role_of_power_system_relays_in_a_large_scale_physical_attack}, abstract = {In this paper we analyze the response of the electric power grid to a hypothetical nuclear attack inside a major city in the US. We assume that the protective devices of the power system located within a given distance of the attack will be affected by the resulting radiation and hence will not work. A probabilistic examination of the resulting power surges indicates that, if left unchecked, the surges can propagate to large distances. However, by protecting the protection system suitably, the effects can be minimized considerably.}, booktitle = {6th {International} {Conference} on {Liberalization} and {Modernization} of {Power} {Systems} and {CRIS} {Problems} of {Critical} {Infrastructures}}, author = {Pal, Anamitra and Youssef, Mina and Vullikanti, Anil and Marathe, Achla and Eubank, Stephen and Marathe, Madhav and Barrett, Chris and Thorp, J.s and Phadke, Arun and Centeno, Virgilio}, month = jun, year = {2015} }
In this paper we analyze the response of the electric power grid to a hypothetical nuclear attack inside a major city in the US. We assume that the protective devices of the power system located within a given distance of the attack will be affected by the resulting radiation and hence will not work. A probabilistic examination of the resulting power surges indicates that, if left unchecked, the surges can propagate to large distances. However, by protecting the protection system suitably, the effects can be minimized considerably.
Partitioned linear state estimation. Chatterjee, P.; Pal, A.; Thorp, J. S.; and De La Ree, J. In IEEE Power Energy Society Innovative Smart Grid Technologies Conference (ISGT), pages 1–5, Washington, DC, February 2015.
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@inproceedings{pal_effect_2015, address = {Washington, DC}, title = {Effect of different load models on the three-sample based quadratic prediction algorithm}, url = {https://ieeexplore.ieee.org/abstract/document/7131811}, abstract = {A quadratic prediction algorithm has been proposed previously that estimates the future state from three preceding values of the same state. The original proof of that algorithm was developed based on loads changing at constant power factor. Since real power system loads are composite in nature, it is important to analyze that algorithm's performance for different load models. This paper studies the effect of constant power load, constant current load, constant impedance load, and the WECC load model on the performance of the three-sample based quadratic prediction algorithm. The analysis is performed using the IEEE-118 bus system, a 4000-bus WECC model, as well as real-data obtained from a utility. The results indicate that the three-sample based quadratic prediction algorithm is able to estimate the states accurately for all the load models.}, booktitle = {{IEEE} {Power} {Energy} {Society} {Innovative} {Smart} {Grid} {Technologies} {Conference} ({ISGT})}, author = {Pal, Anamitra}, month = feb, year = {2015}, keywords = {Heuristic algorithms, Impedance, Load modeling, Load models, Mathematical model, Phasor measurement unit (PMU), Power system dynamics, Prediction algorithms, Predictive models, Quadratic prediction, State estimation}, pages = {1--5}, }
abstract A quadratic prediction algorithm has been proposed previously that estimates the future state from three preceding values of the same state. The original proof of that algorithm was developed based on loads changing at constant power factor. Since real power system loads are composite in nature, it is important to analyze that algorithm's performance for different load models. This paper studies the effect of constant power load, constant current load, constant impedance load, and the WECC load model on the performance of the three-sample based quadratic prediction algorithm. The analysis is performed using the IEEE-118 bus system, a 4000-bus WECC model, as well as real-data obtained from a utility. The results indicate that the three-sample based quadratic prediction algorithm is able to estimate the states accurately for all the load models.
A PMU placement scheme ensuring real-time monitoring of critical buses of the network. Pal, A.; Sanchez-Ayala, G. A.; Centeno, V. A.; and Thorp, J. S. IEEE Transactions on Power Delivery, 29(2): 510–517. April 2014.
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@article{pal_pmu_2014, title = {A PMU placement scheme ensuring real-time monitoring of critical buses of the network}, volume = {29}, url = {https://ieeexplore.ieee.org/abstract/document/6595642}, abstract = {This paper presents a phasor measurement unit (PMU) placement scheme that provides real-time monitoring of key buses of the network. High-voltage lines, substations relevant for transient and dynamic stability of the network, and buses with high connectivity are given the highest priority while placing the PMUs. Binary integer programming and “depth of unobservability†are used to find the relevant PMU placement set. The placement scheme has been tested on the IEEE 118-bus system, IEEE 300-bus system, a 283-bus model of the Central American Power Transmission System, and a complex 996-bus network describing the Northern and the Eastern power grids of India. The results indicate that the proposed technique will be useful to utilities that want to initially protect the most important buses of their system on their way to attaining complete observability.}, number = {2}, journal = {IEEE Transactions on Power Delivery}, author = {Pal, Anamitra and Sanchez-Ayala, Gerardo A. and Centeno, Virgilio A. and Thorp, James S.}, month = apr, year = {2014}, keywords = {Binary integer programming, observability, Observability, Phasor measurement units, phasor measurement units (PMUs), Power system stability, redundancy, Redundancy, Stability analysis, Transient analysis, wide-area measurement system (WAMS)}, pages = {510--517}, }
This paper presents a phasor measurement unit (PMU) placement scheme that provides real-time monitoring of key buses of the network. High-voltage lines, substations relevant for transient and dynamic stability of the network, and buses with high connectivity are given the highest priority while placing the PMUs. Binary integer programming and “depth of unobservability†are used to find the relevant PMU placement set. The placement scheme has been tested on the IEEE 118-bus system, IEEE 300-bus system, a 283-bus model of the Central American Power Transmission System, and a complex 996-bus network describing the Northern and the Eastern power grids of India. The results indicate that the proposed technique will be useful to utilities that want to initially protect the most important buses of their system on their way to attaining complete observability.
Transient stability prediction based on apparent impedance trajectory recorded by PMUs. Li, M.; Pal, A.; Phadke, A. G.; and Thorp, J. S. Int. J. Elect. Power Energy Syst., 54: 498–504. January 2014.
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@article{li_transient_2014, title = {Transient stability prediction based on apparent impedance trajectory recorded by {PMUs}}, volume = {54}, url = {https://www.sciencedirect.com/science/article/pii/S0142061513003207}, abstract = {Traditional methods for predicting transient stability of power systems such as the direct method, the time domain approach, and the energy function methods, do not work well for real-time stability predictions. The use of Phasor Measurement Units (PMUs) appears to alleviate this problem by providing information in real-time for transient stability assessment and enhancement. Techniques such as the rotor oscillation prediction method based on time series have made the prediction of system stability possible for real-time applications. However, such methods often require more than 300ms after the start of a transient event to make reliable predictions. This paper proposes using the trajectory of the apparent impedance recorded by PMUs placed at strategic locations in the power system to rapidly predict transient stability. From the simulations performed, it is realized that system stability can be predicted in approximately 200ms (12cycles). The main advantage of this method is its simplicity as the PMUs can record the apparent impedance trajectories in real-time without any previous calculation. Moreover, using decision trees built in CART®, transient stability prediction becomes straightforward and computationally very fast. The optimum locations for PMU placement can also be determined using this technique.}, journal = {Int. J. Elect. Power Energy Syst.}, author = {Li, Meiyan and Pal, Anamitra and Phadke, Arun G. and Thorp, James S.}, month = jan, year = {2014}, keywords = {Apparent impedance trajectory, Classification and Regression Tree (CART), Complex synchrophasor data, Decision trees, Fisher’s Linear Discriminant (FLD), Transient stability}, pages = {498--504}, }
Traditional methods for predicting transient stability of power systems such as the direct method, the time domain approach, and the energy function methods, do not work well for real-time stability predictions. The use of Phasor Measurement Units (PMUs) appears to alleviate this problem by providing information in real-time for transient stability assessment and enhancement. Techniques such as the rotor oscillation prediction method based on time series have made the prediction of system stability possible for real-time applications. However, such methods often require more than 300ms after the start of a transient event to make reliable predictions. This paper proposes using the trajectory of the apparent impedance recorded by PMUs placed at strategic locations in the power system to rapidly predict transient stability. From the simulations performed, it is realized that system stability can be predicted in approximately 200ms (12cycles). The main advantage of this method is its simplicity as the PMUs can record the apparent impedance trajectories in real-time without any previous calculation. Moreover, using decision trees built in CART®, transient stability prediction becomes straightforward and computationally very fast. The optimum locations for PMU placement can also be determined using this technique.
Impact of a surface nuclear blast on the transient stability of the power system. Barrett, C. L.; Centeno, V.; Eubank, S.; Yaman Evrenosoglu, C.; Marathe, A.; Marathe, M. V.; Mishra, C.; Mortveit, H.; Pal, A.; Phadke, A.; Thorp, J.; Vullikanti, A.; and Youssef, M. In Proc 9th Int. Conf. Critical Information Infrastructures Security, pages 1–10, Limassol, Cyprus, Oct 2014.
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@inproceedings{barrett_impact_2014, author = {Barrett, Christopher L. and Centeno, Virgilio and Eubank, Stephen and Yaman Evrenosoglu, Cansin and Marathe, Achla and Marathe, Madhav V. and Mishra, Chetan and Mortveit, Henning and Pal, Anamitra and Phadke, Arun and Thorp, James and Vullikanti, Anil and Youssef, Mina}, year = {2014}, title = {Impact of a surface nuclear blast on the transient stability of the power system}, pages = {1--10}, month={Oct}, booktitle={Proc 9th Int. Conf. Critical Information Infrastructures Security}, address = {Limassol, Cyprus} }
Stress assessment in power systems and its visualization using synchrophasor based metrics. Pal, A.; Singh, I.; and Bhargava, B. In IEEE 2014 North American Power Symposium (NAPS), pages 1–6, Pullman, WA, September 2014.
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@inproceedings{pal_stress_2014, address = {Pullman, WA}, title = {Stress assessment in power systems and its visualization using synchrophasor based metrics}, url = {https://ieeexplore.ieee.org/abstract/document/6965460}, abstract = {This paper proposes two metrics for assessing static and dynamic stresses present in a large interconnected power grid. The base loading of the system constitutes the static stress. It refers to the normal/pre-contingency state of the system. The dynamic stress refers to the event/contingency that the system is subjected to and is primarily caused by loss of transmission system or drop in generation. The angle difference between buses located across the network, and the voltage sensitivity of buses lying in the middle are two synchrophasor-based metrics that are found to accurately reflect the system's static loading and its ability to withstand the dynamic stress. The simulations performed using the full WECC system show that by monitoring these metrics in real-time, the ability of the system to withstand a variety of contingencies can be predicted with great accuracy. These metrics can be monitored through analytic and visualization platforms such as RTDMS®1, which is a synchrophasor based software application. The methodology to be followed for integrating with such a platform is also provided. The analysis shows that the proposed metrics can be very effective in aiding system operators for real-time static and dynamic stress monitoring.}, booktitle = {{IEEE} 2014 {North} {American} {Power} {Symposium} ({NAPS})}, author = {Pal, Anamitra and Singh, Iknoor and Bhargava, Bharat}, month = sep, year = {2014}, keywords = {Angle difference, Loading, Monitoring, Phasor measurement unit (PMU), Power system dynamics, Real-time systems, Sensitivity, Stress, Stress assessment, Voltage sensitivity, Wide area measurement system (WAMS)}, pages = {1--6}, }
This paper proposes two metrics for assessing static and dynamic stresses present in a large interconnected power grid. The base loading of the system constitutes the static stress. It refers to the normal/pre-contingency state of the system. The dynamic stress refers to the event/contingency that the system is subjected to and is primarily caused by loss of transmission system or drop in generation. The angle difference between buses located across the network, and the voltage sensitivity of buses lying in the middle are two synchrophasor-based metrics that are found to accurately reflect the system's static loading and its ability to withstand the dynamic stress. The simulations performed using the full WECC system show that by monitoring these metrics in real-time, the ability of the system to withstand a variety of contingencies can be predicted with great accuracy. These metrics can be monitored through analytic and visualization platforms such as RTDMS®1, which is a synchrophasor based software application. The methodology to be followed for integrating with such a platform is also provided. The analysis shows that the proposed metrics can be very effective in aiding system operators for real-time static and dynamic stress monitoring.
Classification trees for complex synchrophasor data. Pal, A.; Thorp, J. S.; Khan, T.; and Young, S. S. Elect. Power Compon. Syst., 41(14): 1381–1396. September 2013.
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@article{pal_classification_2013, title = {Classification trees for complex synchrophasor data}, volume = {41}, url = {https://www.tandfonline.com/doi/abs/10.1080/15325008.2013.824048}, abstract = {Classification and regression trees (CART) has been used for various applications in power systems. In most of these applications, phasor data obtained from phasor measurement units are used for building the decision tree. However, the splits in CART are based on a single attribute or a combination of variables chosen by CART itself rather than the user. But as phasor measurement unit data are complex numbers, both the attributes—real and imaginary—should be considered simultaneously for making critical decisions. For example, changing the reference bus in situations where the split is only on the real or imaginary part of a complex voltage (or current) measurement can cause the performance of the tree to degrade significantly. An algorithm is proposed in this article to allow splits on complex synchrophasor data. The methodology is implemented on two systems: a detailed model of the California Power System, where it is used for developing an adaptive protection scheme, and the IEEE 118-bus system, where it is used to classify dynamic events based on trajectories of voltage measurements obtained from phasor measurement units. MATLAB® (The MathWorks, Natick, Massachusetts, USA) implementation of classification and regression trees (classregtree.m) has been used for performing both analyses.}, number = {14}, journal = {Elect. Power Compon. Syst.}, author = {Pal, Anamitra and Thorp, J. S. and Khan, Taufiquar and Young, S. Stanley}, month = sep, year = {2013}, keywords = {classification and regression trees, decision trees, Fisher's linear discriminant, linear discriminant analysis, synchrophasors, wide-area measurement system}, pages = {1381--1396}, }
Classification and regression trees (CART) has been used for various applications in power systems. In most of these applications, phasor data obtained from phasor measurement units are used for building the decision tree. However, the splits in CART are based on a single attribute or a combination of variables chosen by CART itself rather than the user. But as phasor measurement unit data are complex numbers, both the attributes—real and imaginary—should be considered simultaneously for making critical decisions. For example, changing the reference bus in situations where the split is only on the real or imaginary part of a complex voltage (or current) measurement can cause the performance of the tree to degrade significantly. An algorithm is proposed in this article to allow splits on complex synchrophasor data. The methodology is implemented on two systems: a detailed model of the California Power System, where it is used for developing an adaptive protection scheme, and the IEEE 118-bus system, where it is used to classify dynamic events based on trajectories of voltage measurements obtained from phasor measurement units. MATLAB® (The MathWorks, Natick, Massachusetts, USA) implementation of classification and regression trees (classregtree.m) has been used for performing both analyses.
Applying a robust control technique to damp low frequency oscillations in the WECC. Pal, A.; Thorp, J. S.; Veda, S. S.; and Centeno, V. A. International Journal of Electrical Power & Energy Systems, 44(1): 638–645. January 2013.
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@article{pal_applying_2013, title = {Applying a robust control technique to damp low frequency oscillations in the {WECC}}, volume = {44}, url = {https://www.sciencedirect.com/science/article/pii/S0142061512004589}, abstract = {This paper demonstrates the application of a robust technique for damping low frequency oscillations in the WECC. The control is designed by extending the logic of SMA and integrating it with the LMI technique to develop a single-gain feedback controller that is capable of damping oscillations in large systems. It is an integrated form of control because it combines different controllers together so as to prevent any negative interaction between the individual controls. The proposed technique is initially applied to an equivalent model of the WECC system developed in MATLAB and then transferred to a larger and more detailed version created in PSLF. The controllers initially used for the design are the two HVDC lines and an SVC. Three ESDs are added to the model for the improvement of the control. The results indicate that the technique proposed in this paper provides adequate damping to the relevant modes of oscillations and that it can be easily applied to large and complex power system networks.}, number = {1}, journal = {International Journal of Electrical Power \& Energy Systems}, author = {Pal, Anamitra and Thorp, James S. and Veda, Santosh S. and Centeno, V. A.}, month = jan, year = {2013}, keywords = {Energy Storage Devices (ESDs), Inter-area oscillations, Linear Matrix Inequalities (LMIs), Polytopic design, Selective modal analysis (SMA), Wide Area Measurements (WAMs)}, pages = {638--645}, }
This paper demonstrates the application of a robust technique for damping low frequency oscillations in the WECC. The control is designed by extending the logic of SMA and integrating it with the LMI technique to develop a single-gain feedback controller that is capable of damping oscillations in large systems. It is an integrated form of control because it combines different controllers together so as to prevent any negative interaction between the individual controls. The proposed technique is initially applied to an equivalent model of the WECC system developed in MATLAB and then transferred to a larger and more detailed version created in PSLF. The controllers initially used for the design are the two HVDC lines and an SVC. Three ESDs are added to the model for the improvement of the control. The results indicate that the technique proposed in this paper provides adequate damping to the relevant modes of oscillations and that it can be easily applied to large and complex power system networks.
A robust control technique for damping inter-area oscillations. Vance, K.; Pal, A.; and Thorp, J. S. In IEEE Power and Energy Conference at Illinois (PECI), pages 1–8, Champaign, IL, February 2012.
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@inproceedings{vance_robust_2012, address = {Champaign, IL}, title = {A robust control technique for damping inter-area oscillations}, url = {https://ieeexplore.ieee.org/abstract/document/6184591}, abstract = {In order to reduce the detrimental effects of inter-area oscillations on system stability, it is possible to use Linear Matrix Inequalities (LMIs) to design a multi-objective state feedback control. The LMI optimization comes up with a control law that stabilizes numerous operating conditions simultaneously using a polytopic model of the system. However, the number of cases to be considered is limited by computational complexity and increased chances of infeasibility. In order to circumvent this problem, this paper presents a method for solving multiple polytopic problems having a common base case. The proposed algorithm determines which polytopic control is necessary for a particular contingency and classifies them as belonging to that polytopic domain. The technique was tested on an 8-machine, 13 bus system and provided satisfactory results.}, booktitle = {{IEEE} {Power} and {Energy} {Conference} at {Illinois} (PECI)}, author = {Vance, Katelynn and Pal, Anamitra and Thorp, James S.}, month = feb, year = {2012}, keywords = {Adaptive selection, Convex combination, Damping, Generators, HVDC Lines, HVDC transmission, Inter-area oscillations, Linear Matrix Inequality (LMI) Control, Mathematical model, Oscillators, Polytopic Model, Power system stability, Stability analysis, Wide Area Measurement Systems (WAMS)}, pages = {1--8}, }
n order to reduce the detrimental effects of inter-area oscillations on system stability, it is possible to use Linear Matrix Inequalities (LMIs) to design a multi-objective state feedback control. The LMI optimization comes up with a control law that stabilizes numerous operating conditions simultaneously using a polytopic model of the system. However, the number of cases to be considered is limited by computational complexity and increased chances of infeasibility. In order to circumvent this problem, this paper presents a method for solving multiple polytopic problems having a common base case. The proposed algorithm determines which polytopic control is necessary for a particular contingency and classifies them as belonging to that polytopic domain. The technique was tested on an 8-machine, 13 bus system and provided satisfactory results.
Dynamic state prediction based on Auto-Regressive (AR) model using PMU data. Gao, F.; Thorp, J. S.; Pal, A.; and Gao, S. In IEEE Power and Energy Conference at Illinois (PECI), pages 1–5, Champaign, IL, February 2012.
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@inproceedings{gao_dynamic_2012, address = {Champaign, IL}, title = {Dynamic state prediction based on Auto-Regressive (AR) model using PMU data}, url = {https://ieeexplore.ieee.org/abstract/document/6184586}, abstract = {This paper presents a dynamic state prediction method based on an Auto-Regressive Model (AR model) using PMU data. In recent years, state prediction has played a key role in improving power system performance and reliability. When load is increased linearly at a constant power factor, it is proved in this paper that the bus voltages are quadratic and the AR model for predicting the next voltage is based on three prior estimates. This logic is then tested on the IEEE-118 bus system. The test results demonstrate that under morning load pick-up, economic dispatch, line opening and generator oscillations, the proposed method is correct and gives valid predictions. Furthermore, based on the error in quadratic fit, it is advocated that this method could be applied to detect abnormal conditions in the transmission systems. Theoretical analysis and results show that the proposed method based on AR model has great potential in predicting power system states.}, booktitle = {{IEEE} {Power} and {Energy} {Conference} at {Illinois} (PECI)}, author = {Gao, Fenghua and Thorp, James S. and Pal, Anamitra and Gao, Shibin}, month = feb, year = {2012}, keywords = {Auto-Regressive (AR) Model, Circuit faults, Dynamic State Prediction, Educational institutions, Load modeling, Mathematical model, Phasor measurement units, Phasor Measurement Units (PMUs), Power system dynamics, Predictive models, State Estimation}, pages = {1--5}, }
This paper presents a dynamic state prediction method based on an Auto-Regressive Model (AR model) using PMU data. In recent years, state prediction has played a key role in improving power system performance and reliability. When load is increased linearly at a constant power factor, it is proved in this paper that the bus voltages are quadratic and the AR model for predicting the next voltage is based on three prior estimates. This logic is then tested on the IEEE-118 bus system. The test results demonstrate that under morning load pick-up, economic dispatch, line opening and generator oscillations, the proposed method is correct and gives valid predictions. Furthermore, based on the error in quadratic fit, it is advocated that this method could be applied to detect abnormal conditions in the transmission systems. Theoretical analysis and results show that the proposed method based on AR model has great potential in predicting power system states.
Co-ordinated control of inter-area oscillations using SMA and LMI. Pal, A.; and Thorp, J. S. In IEEE Power Energy Society Conference on Innovative Smart Grid Technologies (ISGT), pages 1–6, Washington, DC, January 2012.
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@inproceedings{pal_co-ordinated_2012, address = {Washington, DC}, title = {Co-ordinated control of inter-area oscillations using {SMA} and {LMI}}, url = {https://ieeexplore.ieee.org/abstract/document/6175535}, abstract = {Selective Modal Analysis (SMA) has been used in the design of WAMS based damping of inter-area oscillations. In conjunction with a Linear Matrix Inequality (LMI) formulation and a polytopic model a single control law can be found to guarantee pole placement for multiple contingencies. The previous attempts have used a model containing all the ε and ω modes, with SMA used to eliminate all other states. In practical applications the resulting system is still too large to use in a polytopic model. This paper presents an algorithm to further reduce the system size to the relevant modes of oscillations. A 16 machine, 68 bus system is used as the test case with PSSs, DC lines and SVCs acting as the control.}, booktitle = {{IEEE} {Power} {Energy} {Society} {Conference} on {Innovative} {Smart} {Grid} {Technologies} ({ISGT})}, author = {Pal, Anamitra and Thorp, James S.}, month = jan, year = {2012}, keywords = {Damping, Eigenvalues and eigenfunctions, Generators, Inter-area oscillations, Linear Matrix Inequality (LMI) Control, Mathematical model, Oscillators, Polytopic Model, Power system dynamics, Reduced order systems, Selective Modal Analysis (SMA), Wide Area Measurements}, pages = {1--6}, }
Selective Modal Analysis (SMA) has been used in the design of WAMS based damping of inter-area oscillations. In conjunction with a Linear Matrix Inequality (LMI) formulation and a polytopic model a single control law can be found to guarantee pole placement for multiple contingencies. The previous attempts have used a model containing all the ε and ω modes, with SMA used to eliminate all other states. In practical applications the resulting system is still too large to use in a polytopic model. This paper presents an algorithm to further reduce the system size to the relevant modes of oscillations. A 16 machine, 68 bus system is used as the test case with PSSs, DC lines and SVCs acting as the control.
Coordinated Control of Inter-area Oscillations using SMA and LMI: A Robust Control Technique for Damping Low Frequency Oscillations. Pal, A.; and Thorp, J. S. Lambert Academic Publishing, Oct 2012.
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@Book{pal_coordinated_2012, year = {2012}, month = {Oct}, publisher = {Lambert Academic Publishing}, title = {Coordinated Control of Inter-area Oscillations using SMA and LMI: A Robust Control Technique for Damping Low Frequency Oscillations}, author = {Pal, Anamitra and Thorp, James S.} }
PMU placement for the central american power network and its possible impacts. Sanchez, G. A.; Pal, A.; Centeno, V. A.; and Flores, W. C. In IEEE Power Energy Society Conference on Innovative Smart Grid Technologies LATIN AMERICA (ISGT LA), pages 1–7, Medellin, Colombia, October 2011.
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@inproceedings{sanchez_pmu_2011, address = {Medellin, Colombia}, title = {{PMU} placement for the central american power network and its possible impacts}, url = {https://ieeexplore.ieee.org/abstract/document/6083202}, abstract = {The Central American Power System (CAPS) comprises of the electrical power networks of Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama. The topology of the network, the geographical distribution of the load and generation blocks, and the localized weaknesses in some sections of the transmission grid have made this system prone to frequent partial or total blackouts. At the same time, this area has the advantage of having a control center that can promote international measures in order to safeguard the integrity of the transmission network. This paper presents a gradual optimal PMU placement approach that guarantees minimum regional observability at the initial stage and full observability for the complete implementation. The paper also states how WAMS can provide real-time information to the control center for a more secure operation of the system. The practical constraints of ensuring real-time monitoring of critical buses of the network are taken into account during PMU Placement.}, booktitle = {{IEEE} {Power} {Energy} {Society} {Conference} on {Innovative} {Smart} {Grid} {Technologies} {LATIN} {AMERICA} ({ISGT} {LA})}, author = {Sanchez, G. A. and Pal, Anamitra and Centeno, V. A. and Flores, W. C.}, month = oct, year = {2011}, keywords = {Binary Integer Programming, Observability, Optimal Placement, Oscillators, Phasor measurement units, Phasor Measurement Units, Power System Monitoring, Power transmission lines, Transmission line measurements, Vectors, Wide Area Measurements}, pages = {1--7}, }
The Central American Power System (CAPS) comprises of the electrical power networks of Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama. The topology of the network, the geographical distribution of the load and generation blocks, and the localized weaknesses in some sections of the transmission grid have made this system prone to frequent partial or total blackouts. At the same time, this area has the advantage of having a control center that can promote international measures in order to safeguard the integrity of the transmission network. This paper presents a gradual optimal PMU placement approach that guarantees minimum regional observability at the initial stage and full observability for the complete implementation. The paper also states how WAMS can provide real-time information to the control center for a more secure operation of the system. The practical constraints of ensuring real-time monitoring of critical buses of the network are taken into account during PMU Placement.