Experimental Study of Open-Switch Faults for Interfacing Inverters in Microgrids Using OPAL-RT Real-time Simulator

With increasing penetration of renewable energy sources in power distribution systems, the microgrid becomes a fundamental building block for grid modernization. Within a microgrid, renewable energy-based distributed generation (DG) units are connected through interfacing inverters. These inverters play an essential role for the microgrid operation by employing advanced control schemes. However, interfacing inverters may fail due to various faults. In this paper, an experimental investigation of open-switch faults for the DG interfacing voltage source inverter (VSI) in microgrids is conducted using the Opal-RT real-time simulator test bench, where three grid-forming inverter control schemes for DGs (droop control, virtual synchronous generator (VSG) control, and VSG with Fuzzy secondary controller) are implemented under healthy and 21 single- and multi-open-switch fault combinations. In addition to three control schemes, five inverter loadings (30%, 45%, 60%, 75% and 90%) are also considered in the testing. Three phase voltage and current signals recorded at the inverter output/load terminal in these experiments provide unique and novel datasets for studying inverter open-switch fault diagnosis in microgrids.