A new approach to defining corrective control actions in case of infeasible operating situations

A method that deals with power system infeasible operating situations is proposed in this paper. In case these situations occur, appropriate corrective actions must be efficiently obtained and quickly implemented by (a) quantifying the system's unsolvability degree (UD), and (b) determining a corrective control strategy to pull the system back into the feasible operating 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, control strategies can be obtained by either the proportionality method (PM) or the nonlinear programming based method (NLPM). Capacitor banks, tap changing transformers and load shedding are the usual controls available. The idea of local search of the available controls is used as a way of using the most effective controls and minimizing the computational burden. Simulations have been carried out for small to large systems, under contingency and heavy load situations. It is shown that the proposed method can be a very useful tool in operation planning studies, particularly for voltage stability analysis.