Computing the Load Margin of Power Systems Using Particle Swarm Optimization

Abstract

The load margin is an important index used in power system operation centers to assess how far the system is from an instability mechanism. Usually, this load margin is calculated considering the Voltage Stability requirements through static models. However, as the load level increases in one direction, low-dampened low-frequency oscillation modes can arise and they compromise the angular stability of the system. Thus, it is important to consider the dynamic model of the system and determine the load margin by meeting the requirements of Voltage and Small-Signal Stability. This article proposes a method based on Particle Swarm Optimization to determine the load margin of power systems meeting the requirements of the Voltage Stability (voltage collapse) and Small-Signal Stability (eigenvalues with low damping). Case studies on the IEEE 39-bus system are presented and discussed.