A strategy for undervoltage load shedding in power systems

Abstract

This paper presents a strategy for undervoltage load shedding in power systems. An undervoltage load shedding (UVLS) criterion is defined using a generic dynamic load model to determine the amount of load to shed at a given voltage. The 'when and where' for load shedding is determined by identifying the weakest node in the network using a voltage collapse proximity indicator (VCPI). The magnitude of the VCPI is determined by estimating the ratio of the impedance of the load to the Thevenin impedance looking into the network at a given voltage. If required, further load shedding can be carried out by observing the VCPI. The strategy is simple, reliable and can be applied to any power system.