Overvoltage Mitigation Approach for Single-Line-to-Ground Faults for Inverter-Based Distributed Generation

This paper discusses an approach designed to mitigate overvoltage issues that can occur during islanded operation of inverter based distributed generation (DG) sources as a result of single-line-to-ground (SLG) faults. The overvoltage was reduced by modifying the inverter output command by using an overvoltage mitigation coefficient in the inverter control logic. Real-time simulations were conducted to validate the effectiveness of the proposed approach. Verficiation results showed that the proposed overvoltage mtigation approach contributed to reducing the overvoltage caused during islanded operation and ensures satisfactory operation of the distribution network operated by inverter based DG sources. Additionally, the study compares the two detection methods and finds that the instantaneous voltage detection-based overvoltage mitigation algorithm excels in responsiveness, while the RMS voltage detection-based algorithm provides a greater overall reduction in overvoltage. Not only the proposed approach contributes to addressing overvoltage concerns as a result of temporary SLG faults and islanded operation, but also could be integrated to existing inverter control algorithms with minimal effort.