Operational Analysis of OCR Due to Application of SFCL in Power Distribution System with Distributed Generations

The application of distributed generations (DGs) is increasing. Because renewable energy is eco-friendly and has low carbon emissions interest on renewable energy based DGs is growing. However, as the number of DGs increases, the fault current magnitude in the system can either increase or decrease during faults. These changes can result in malfunctions or failure of overcurrent relays (OCRs), potentially leading to a large blackout. Research on superconducting fault current limiter (SFCL) to limit fault currents has been conducted, but applying SFCLs in distribution systems with DGs can complicate protective coordination among relays. In this paper, cases of malfunction and failure of OCRs due to the connection of distributed power sources were analyzed, and method to improve the protective coordination of OCRs using SFCLs were proposed.