A Method Of Determining The PDSR Based On EEAC And The Application Of PDSR In A New Optimal Power Flow Model

The modern interconnected bulk power systems will not only bring us huge economic and social benefits, but also suffer more transient stability and dynamic security problems that usually cause more extensive and serious damages and losses. Therefore, how to analysis them is an extremely important task for power system planning and operation.In recent years Dynamic Security Region (DSR) and Extended Equal Area Criterion (EEAC) have received considerable attention in the field of dynamic security assessment and control in electrical power system, and both of them have made significant achievements. The time domain method for determining the critical points in power injection space needs lots of computation time. Based on EEAC, this paper develops a rapid method to determine DSR. The critical fault clear time can be calculated rapidly by EEAC for a given node power injection point under a given fault, thus a critical point can easily be obtained for a search direction. When enough critical points according to different search directions are acquired, the DSR boundary approximately in the form of hyper-plane is got by the least square method.Based on PDSR a new optimal power flow model is proposed. The objective of the problem is to minimize the expected total cost of operating the system. The expected cost includes the cost of operating the system in the pre-contingency operating state, the emergency control and each of the post-contingency operating states. Based on the fact that the boundary of the DSR is approximately represented by the hyper-plane, a linear inequation is used to judge whether the running point is transient stable. The emergency control cost is calculated by the method based on PDSR.