Finding points of maximal loadability considering post-contingency corrective controls

•A method for finding maximal loadability with corrective controls is presented.•The method is based on approximations of the stability boundary.•The method can be applied both in planning and in operation.

Lately, much work in the area of voltage stability assessment has been focused on finding post-contingency corrective controls. In this article a contribution to this area will be presented where we search for maximal loadability while considering post-contingency corrective controls. This objective is different from the usual approach to the problem, where the aim is to include the post-contingency controls in a security-constrained optimal power flow.Our approach gives us an optimal control problem with a variable start point. Optimal control problems are generally very cumbersome to solve in high dimensions. However, under some mild assumptions we find that our infinite dimensional optimization problem can be transformed into a finite dimensional one. More specifically, by assuming that the load recovery is an explicit function of time we can specify a set of constraints that are necessary for optimality.