Study on control system of three-phase bridge type current limiter with magnetic bias

The designed control system of three-phase FCL (Fault Current Limiter) consists, of three single-phase bridge type FCLs with magnetic bias, three current-limiting reactors, excitation power supply system and power grid monitoring system. It adopts two DSPs as its core: one is to provide excitation current for the limiter; the other is to monitor the three-phase currents and voltages of power grid real-timely and sends control parameters in time to excitation controller through CAN bus when short circuit fault is detected. Its control principle is analyzed and its software and hardware design presented. The designed digital excitation controller based on DSP and FPGA may overcome the even frequency reverse electromotive force. Various short circuit experiments are carried out on the prototype with rated voltage of 380 V, rated current of 150 A and maximal fault current of 1000 A. Results show that the designed control system is feasible and effective.