Voltage profile optimization as influenced by power‐system configuration

Abstract

This paper extends a linear-programming optimization-based method proposed before for reactive-power scheduling using generator terminal voltages and reactive powers, transformer tap-settings and switchable reactive power sources as control variables. The system configuration following contingencies is considered - for the first time - as an additional control variable in the optimization-method. It is proposed to use all of tile possible modifications of system configuration by opening one or two lines simultaneously. For this to be accurately achieved, a technique was proposed for ranking the line outages, which is based on system losses obtained by AC and/or DC load-flow studies. The ranking agreed satisfactorily with the voltage-reactive power index used for contingency analysis in system security studies. Voltage stability is checked before and after optimum adjustment of the control variables and proved to be better after optimum adjustment.