Bidirectional solid current-limiter for HVDC grids

High-voltage direct current (HVDC) grids have been assumed as a promising technology for its advantages in accommodation and integration of large-scale renewable energy. However, the fault current increases dramatically once the fault occurs in HVDC grids, which makes great difficulty in fault clearance. Therefore, it is necessary to take some measures to limit the fault current. A bidirectional solid current-limiter (BSCL) topology is proposed. The BSCL can improve the performance of inductors to limit DC fault currents through the high-frequency switching between two current-limiting branches. Besides, the BSCL can be installed at both ends of a DC transmission line or between a converter and a DC bus. The feasibility of the proposed topology is demonstrated in power systems computer-aided design/electro-magnetic transient design and control. Simulation results indicate that the BSCL can effectively limit the rising speed and the amplitude of short-circuit currents, decrease the maximum breaking currents of DC breakers and improve the breaking speed of DC breakers.