Corrective control strategies in case of infeasible operating situations

A new method that deals with power systems infeasible operating situations is proposed in this paper. In case these situations occur, appropriate corrective actions must be efficiently obtained and quickly implemented. In order to accomplish this, it is necessary (a) to quantify the systems unsolvability degree (UD), and (b) to determine a corrective control strategy to pull the system back into the feasible operation region. UD is determined through the smallest distance between the infeasible (unstable) operating point and the feasibility boundary in parameter (load) space. In this paper the control strategies can be obtained by two methods, namely the proportionality method (PM) and the nonlinear programming based method (NLPM). Capacitor banks, tap changing transformers and load shedding are the usual controls available. Simulations have been carried out, for small to large systems, under contingency and heavy load situations, in order to show the efficiency of the proposed method. It can be a very useful tool in operation planning studies, particularly in voltage stability analysis.