Preventive-corrective demand response to improve short-term voltage stability and transient stability in power systems

This paper proposes a novel approach aiming to counteract short term voltage fluctuations and transient instability by employing centralized emergency demand response. The objectives in this optimization model include a proposed short-term voltage stability index, inversed transient stability margin and system operation cost. Combined demand response actions of load shedding and load recovery are applied during the corrective period. To reduce computational complexity, load shedding bus candidates are selected based on trajectory sensitivity ranking with respect to the load shedding quantities. Then the optimization model is solved via multiobjective evolutionary algorithms (MOEAs). Compared with existing practices, this work not only coordinates between preventive control (PC) and corrective control (CC) actions, but also considers a proposed user disruption indicator to reflect power supply deviation from nominal demand during load shedding and load recovery periods. A comprehensive three-dimensional Pareto-optimal tradeoff solution is computed for decision-making. The proposed method is verified by simulation results on the IEEE 39-bus system.