The dynamics of system voltage instability

Abstract

A method of simulating the post-disturbance dynamics of system voltage instability has been developed in which both the slow and fast phases, reported in incidents, have been replicated by a series of load flows. An analysis of the simulation has shown that changes of voltages and reactive power outputs can not only identify a critical situation but also delineate the affected locality where measures could most usefully be applied. The simulation has unearthed the core problems that must be overcome, the unsustainable increase in transmission line series reactive power losses and the subsequent action of rotor overcurrent protection.