Research On Protection Scheme For Distribution Network With Distribution Generations

With the expansion of the power system, power system reliability becoming more and more important. Static voltage stability is becoming a hot research topic. Power system is a typical nonlinear system. Power supply capacity is constrained by many factors and the load is limited. The so-called static voltage stability limit refers to operating state when the load is maximum. There are many ways to find this voltage and load limits. This paper mainly discusses the continuation power flow method and interior point methodand an improved continuation power flow is proposed. Continuation power flow method is simple and the program is easy to code, but its calculation speed is slow and the direction of the load growth is constant; interior point methods is relative complex, but the calculation speed is higher and the direction of the load growth is relaxed. The propsoed improved continuation power flow method also allows a free growth direction of the load,the load can come closer the threshold voltage. The propsoed method is copmpared with the continuation power flow method and interior point method and the validity and effectiveness are illustrated by the IEEE14 and IEEE30 node systems.