The Voltage Stability Analysis Based On CPF And Bifurcation Theory

The development of the load growth and long distant large capacity transmissionbrings both angle stability problem and voltage instability. The voltage instabilityusually occurs when the load increases a little near to the limit of load,the voltage willdrop sharply even lose stability.Calculation of PV(QV)curve of every node can indicatetwo important parameter critical voltage and power limit clearly.It can also show theability of keeping voltage stability of every node.This paper solves the CPF by continuation method to trace the wholePV(QV)curve,improves the key predictor-corrector technique to make it more exactlyand effectively.The bifurcation points on the curve are found by bifurcation theory tocalculate the power limit exactly.The indices of voltage oscillation and voltage collapsebased on eigenvalues are proposed.The effects of OLTC positive/negative effect onvoltage stabilityare also analyzed byPV curve.Simulation of manysystems indicates thecorrectness.