Reduction of Frequency Oscillations in Solar PV Microgrid using Virtual Synchronous Machine

Abstract

Microgrids are expected to become an integral part of the future power systems which will have a significant contribution from renewable energy sources. The absence of rotating inertia in the power electronic converters used to interface the renewable energy source to the microgrid can cause larger frequency deviations and oscillations in microgrids when compared to the synchronous generator dominated power systems. The concept of providing virtual inertia to the power electronic converters with the help of electrical energy storage is considered as a promising solution to allow more penetration of inertia-less converters for renewable energy integration. The power electronic converters with virtual inertia properties and which imitate the behaviour of synchronous machines either completely or partially are generally known as virtual synchronous machines. In this paper, the effect of a virtual synchronous machine connected to a microgrid with high penetration of solar PV in reducing the frequency deviations and oscillations is studied. The virtual synchronous machine model used in this study is a lower order model based on the swing equation of a synchronous generator. The results obtained from this study indicate that the virtual synchronous machine helps to reduce the maximum frequency deviations and to damp the frequency oscillations occurring due sudden load transients.