Modelling and Analysis of Fault Behaviour of Inverter Microgrids to Aid Future Fault Detection

This paper investigates the fault behaviour of an inverter-only supplied microgrid by computer simulation and numerical analysis. The purpose of this study is to give a qualitative and quantitative understanding of the dynamics involved in a microgrid under fault conditions in order to supply a tool to help the design of a suitable fault detection strategy. After considering first the nature of microgrids and the control of stand-alone inverters, a model of a microgrid supplied by one single inverter-interfaced source is simulated in PSCAD for two different faults conditions. Simplifications to the inverter model which captures its behaviour under fault conditions are then proposed. Finally the effectiveness of the simplified model is demonstrated using a sequence-component-based fault analysis of the microgrid test network.