Emergency voltage control using search and predictive control

This paper presents a method of optimal coordination of load shedding, capacitor switching and tap changer operation using a dynamic system model in order to preserve or retain long-term voltage stability. The method is based on model predictive control and tree search. A model of the controlled system, including the network and load dynamics, is used to predict the future system behaviour based on the current state and applied control actions. The optimal control state according to these predictions is then obtained using a search method similar to those used in chess computers. A detailed and three simplified predictors are presented, along with a tuning procedure that aims to ensure that a minimum amount of emergency control is scheduled by the controller. (C) 2002 Elsevier Science Ltd. All rights reserved.