Voltage Stability Control Based on Real Power Flow Tracing

After some disastrous instabilities and blackouts, power system voltage stability has drawn even more attention. When a serious fault occurs, proper control should be quickly adopted to terminate the system deterioration. In this paper, a control method based on power flow tracing is presented to enhance power system voltage stability. Firstly, a branch-admittance-decreasing algorithm is introduced to determine the minimum power cutting after a serious fault. Power flow tracing is then used to allocate the power to load and generator buses so as to get the corresponding load shedding and generation tripping. Comparing with the previous methods based on power flow sensitivity, the presented method can appropriately consider influence of some nonlinearities in power system, such as the discrete tap changing of OLTC, exciter hard-limit. Since power flow tracing is mainly used in the congestion management, allocation of power loss and transmission charges in the deregulation study, the presented method is compatible to the power system operation under deregulation. Finally, New-England system and IEEE 118-bus system are employed to verify the effectiveness of the presented method.