Oscillatory Stability Analysis for Power Systems with High Penetration of Photovoltaic Generation: the Minimum Characteristic-Locus Method

This article investigates the impact of various photovoltaic (PV) penetration levels on the power system oscillatory stability. An extended Heffron-Philips model is presented, which includes dynamic model of PV generation. To assess the contribution of PV mathematically, the analysis is based on a new technique, the minimum characteristic-locus method. The simulation results indicate that as PV penetration increases, the oscillatory stability curves could be non-monotonic. It improves the stability when PV penetration is lower than a certain value, but if the penetration continues to grow, the positive effect will be diminished, and much higher penetration even will affect the oscillation mode detrimentally. This paper derives a simple form of K1-K6 constants of multi-machine system by using the method of partitioned matrix. Furthermore, it is proposed that exploring the structural characteristics of the coefficient matrices is the key to explain how PV generations affect the power system oscillatory stability.