A capacitor-type DC circuit breaker for offshore all-DC grids

Full DC of offshore wind farms is the future development trend of large-scale offshore wind farms, however, the probability of DC line faults is high, and the use of DC circuit breakers can realise the fault ride-through of offshore full DC wind farms, improve the safe operation of the system during faults, and is one of the mainstream solutions to realise DC fault isolation. In this paper, a capacitive DC circuit breaker suitable for offshore full DC grid is proposed, which can effectively suppress the fault current by introducing a current limiting device. The topology and working principle of this circuit breaker are analysed, and the circuit breaker fault handling process is theoretically analysed. Finally, for the single-end equivalent system using capacitor-type DC circuit breaker, a simulation model is established in Matlab/Simulink software for verification, and the simulation results show that the proposed circuit breaker has a better current limiting effect and has the ability to isolate faults quickly.