Design Improvement of Fault Current Limiter Based on High Coupled Split Reactor Considering the Impact of Internal Ground Fault

The fault current limiter (FCL) based on high coupled split reactor (HCSR), namely HCSR-FCL, is a new technology developed in recent years to realize short-circuit current suppression and interruption. This paper investigates the impact of the internal ground fault on the HCSR-FCL, based on the analysis of its basic principle and internal structure, and proposes two improved schemes for the wiring mode and the current-transformer (CT) configuration. Through the theoretical and simulation analysis, the performance of the original scheme and the two improved schemes under various internal ground fault cases are compared. The results show that when the HCSR-FCL of the original configuration scheme is in the current-sharing state and its switch-arm (SA) has an internal ground fault, the current-limiting arm (CA) will lose its shunting function, and the fast switch has to cut off the short current more than twice of the normal fault and bear the excessive voltage, threatening the safety of the FCL and the stability of the system. Both of the two improved schemes can solve this problem, and ensure the reliability and the effectiveness of the FCL, to provide a reference for the development and engineering application of the HCSR-FCL.