A preventive/corrective model for voltage stability incorporating dynamic load-shedding

This paper presents a preventive/corrective control model to prevent and correct for voltage instability taking into account the load-shed dynamics. An OPF based model is proposed that provides an integrated framework to determine the optimal location, level, timing, and number of loads to be shed to maintain a pre-specified voltage stability margin (SM). The model essentially evaluates the trade-off among the three attributes for all load buses explicitly taking into account the SM constraint. A statistical approximation procedure to model the distance from point of collapse is introduced for both preventive and corrective modes. The preventive model takes into account multiple contingencies. The aim is to determine optimal controls that satisfy all the contingencies simultaneously. The corrective model is based on linear programming for fast calculation of controls in real-time to correct for voltage instability due to a specific contingency condition. (C) 2003 Elsevier Science Ltd. All rights reserved.