Optimal reactive power control of inverter-based distributed generator for voltage stability insight using Particle Swarm Optimization

In many countries, past large-scale blackouts were caused by voltage instability phenomenon and it is of prime importance to enhance the voltage stability in order to realize stable power supply. This paper presents a methodology to increase loading margin (LM) in terms of voltage stability by using reactive power support of distributed generation (DG), in particular photovoltaic, considering the operating limits of power system components such as generators. The proposed method is based on optimal active and reactive power dispatch from DGs under normal and contingency conditions. Here, a trade-off relationship between reactive power injection and active power curtailment was carefully considered in optimizing the DG's contributions. The proposed method is based on Particle Swarm Optimization and its effectiveness was verified in Malaysian Electric Power System model along with constant power loads. It was observed through simulation results that optimal reactive power injection from DGs improved the maximum loading under the voltage stability constraint.