Fault Detection System for 500 kV AC Fault Current Limiter Based on High-Coupled Split Reactor

Aiming at the problem of limiting high short-circuit current in 500 kV AC power grid, we develop an economical-type fault current limiter (FCL) based on high-coupled split reactor (HCSR), namely, HCSR-FCL. This paper addresses designing the early fault detection system of HCSR-FCL. Firstly, it introduces the working principles of HCSR-FCL and gives the system design of HCSR-FCL control system. Subsequently, it discusses the real-time requirement of the HCSR-FCL control system, and apply an early short-circuit fault detection algorithm based on the ratio of the summation of squared three-phase currents (SSC). Then, it gives implementation of the applied algorithm, and also designs the hardware of fault detection unit. Finally, simulation verification on RTDS (real-time digital simulation system) platform is given. Experimental results show that the designed system can detect short-circuit fault rapidly and robustly. When short-circuit occurs, the control system designed can output control signals, which enables the FCL into operation quickly.