Equivalent network for determination of voltage stability limit

In order to improve the efficiency of power system voltage stability analysis a new static equivalent method is presented in this paper including the selection of the correlation area using L₁ index described in detail. The correlation area selected from the external area is composed of generators, buses, transformers and loads. The proposed equivalent method is a kind of modified Ward-type equivalent. This method can increase the computation velocity and remain the precision of the voltage stability limits. Test results of a real power system have proved that this new equivalent method is promising for voltage stability study of power system.