Power Flow Calculation Method for Islanded Power Network

In the practical power system operation, sometimes, some reasons will lead to local power network splitting, generate islanded power network operating. In order to ensure islanded power network operation safety and stability, it is urgently need to know power flow distribution for islanded power network. However, conventional power flow model can´t reflect the important features for islanded power network operating, power flow distribution calculated by using conventional power flow model also don´t agree with practice. So, based on practical power system operation, a new mathematic model of power flow calculation is established for islanded power network in this paper. The new model not only has obvious physical significance, and conforms to the closed-loop regulation laws of practical power system operating, but also it doesn´t need setting slack bus, all generator units with speed governing system and excitation control system undertake changing load together according to setting self-generator parameters at open-loop time, and gets rid of the drawbacks which caused by conventional power flow model when calculates islanded power network´s power flow by using it. The new model has important application value for solving engineering problem for islanded power network. Simulating the power flow distribution of normal operation state, cutting generator unit, cutting load and secondary regulation by using IEEE 30-bus system, the results show that the new model is effective and practical.