Optimal Transmission Planning Based on Quantitative Security Risk

A sound transmission network ensures the secure and economical operation of power system. Several large- scale blackouts in the world have attracted attentions to dynamic and static security of transmission expansion planning. This paper points out that the security risk of transmission system, expressed by quantitative indices, should be considered in the objective function. In order to ensure a flexible transmission system, with probabilistic N-1 safety criteria, this paper builds a transmission planning model considering both static security risk and dynamic security risk. A global optimization framework is developed to resolve the problems caused by the multi-object mathematical model and remarkably reduce the computational burden. Based on EEAC, the proposed method can calculate the stability margin and dynamic risks, identify the grid bottleneck, and can provide guidance to the line expansion. A numerical example is presented to illustrate the validity of the method.