Post contingency shunt reactive switching in voltage stability limited load areas

Abstract

Post transient power flow simulation methodology to determine the voltage stability transfer limit includes assuming switchable shunt capacitors fixed at precontingency values, unless information demonstrates shunt capacitor switching will reliably occur post contingency in a voltage stability limited load area. This paper describes an efficient simulation method to determine whether shunt capacitors will reliably switch post contingency. The method uses the power flow model with the constant MVA loads replaced with distribution equivalents that represent the distribution voltage regulating transformer, feeder impedance, and load components modeled with the static constant power, constant current, and constant impedance components. Sequential power flow solutions show the system effects of each distribution load voltage regulator tap change. Relay cut-in settings for switchable shunt capacitors can be determined.