Traditional sensitivity method for active power corrective control are often based on the isolated indices of line loading rates

which may cause repeated or inefficient adjustment. The theory of security region is applied in analysis of problems in traditional methods. In the security region

the security distance from the operation point to the boundaries is obtained to quantify the security margin and provide guidance for optimal security control. On this basis

the concept of security distance sensitivity is proposed. Then

the generators are matched to opposite equal quantities according to their security distance sensitivities and actual adjustable abilities. Finally

the generators are selected in sequence prior to solving the linear programming problem. Simulation results of IEEE 39-bus system and a certain power grid show that this method is more intuitive and effective than the traditional one when dealing with multi-overload cases. In addition

as the security margin of other branches could also be considered in this method

repeated adjustment can be avoided.