FAULT DURATION FOR VOLTAGE INSTABILITY AND VOLTAGE COLLAPSE INITIATION AS INFLUENCED BY GENERATOR VOLTAGE MAGNITUDES (GVM)

Abstract

The occurrence of voltage instabilities or voltage collapses depend on the duration of the persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities or collapse is the main goal of this paper. The effect of the generators terminal voltages magnitudes (GVM) on fault duration which causes voltage instability initiation is investigated. The fault which leads to voltage instability is found to be three-phase short-circuits at certain load bus and cleared without any variation in the transmission system elements, i.e. the post-fault network conditions will be the same as its pre-fault conditions. Also, this paper searches for the effect of GVM on fault duration for voltage collapse. Where, some line opening in the studied system can be lead to occur the phenomena of voltage collapse initiation.