Summary
Microgrids (MGs) have attracted attention for their ability to enhance power-supply resilience; however, they face several challenges, among which fault detection is a critical issue from the perspective of human safety. Faults can be classified into short circuits and earth faults. The magnitude of the earth-fault current is determined by the ground voltage, fault resistance, presence of an earth-voltage transformer (EVT), and system capacitance. Owing to the operational characteristics of MGs, the disconnection of the EVT and a reduction in system capacitance are likely to occur, making earth-fault detection difficult. Connecting the EVT and line-to-ground capacitors to the main source within the MG is considered an effective solution.
Read more Read lessHowever, it remains unclear whether these countermeasures are equally effective across various
MG configurations. This study verified the effectiveness of countermeasures for various MG configurations. The simulation results confirmed that the developed model could reproduce the experimental conditions and that the countermeasures were effective across different MG configurations. In inverter-based MGs, the inrush current during startup is recognized as a significant challenge. Soft start was evaluated as a countermeasure, and the inrush current was suppressed. However, earth-fault protection must be maintained during this process. The analysis confirmed that excessively long soft-start durations may influence compliance with earth-fault protection requirements.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | C6_10980_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Japan |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
ITO Rei - TEPCO Holdings, Inc. Japan; YOSHIYAMA Kazuhiro - TEPCO Holdings, Inc. Japan; MORITA Shinya - TEPCO Holdings, Inc. Japan; KOIZUMI Ryohei - TEPCO Power Grid, Inc. Japan; KAWANO Shunsuke - Mitsubishi Electric, Corp. Japan
Keywords
Fault detection, inrush-current mitigation, inverter-based microgrid
