Analysis of Protection Coordination Characteristics between Overcurrent and Overvoltage Relays with Application of Fault Current Limiter in Power Distribution System Integrated with Distributed Generation

As global environmental concerns intensify, the development and advancement of renewable energy applications have gained increasing importance. However, the growing integration of distributed generation (DG) from renewable energy sources has amplified its impact on power system faults, prompting active research into protection strategies for power systems with DG. The increasing adoption of DG from renewable energy sources has resulted in a rise in fault current levels. To address this issue, superconducting fault current limiter (SFCL) has been introduced, leading to extensive research and ongoing commercialization. Another challenge of DG is the occurrence of overvoltage during islanding conditions. SFCL can contribute to voltage drops when an overvoltage occurs. To mitigate this problem, it is essential to analyze the protection coordination characteristics between the overcurrent relay (OCR) and the overvoltage relay (OVR). This study used PSCAD/EMTDC simulations to investigate the operation of the OCR, OVR, and magnetic-coupling type SFCL in mitigating overvoltage issues under islanding conditions in distributed generation. The results indicate that the application of the SFCL limits the current and causes a voltage drop, which in turn delays the operation of the OVR. This problem could be solved by adjusting the Time Dial(TD) setting of the OVR.