The voltage-source-converter-based high-voltage direct-current(VSC-HVDC) grid based on hybrid DC circuit breaker protection needs to perform a fast reclosing operation on the faulty line after DC fault is cleared. During the fault recovery process of isolated station reclose to fault cleared state in VSC-HVDC system
there will be intense power fluctuation which will result in slow power recovery during the reclosing process
thus the requirements of DC grid fast reclosing can not be met. Firstly
based on the topology of hybrid direct current circuit breaker(HDCCB)
a fast reclosing procedure with a minimum operation time is proposed in this paper. Furthermore
based on the control system and the fault interruption process of VSC-HVDC grid
the cause of power fluctuation during the reclosing process is revealed. Then an optimized fast reclosing strategy is proposed to realize a fast fault recovery process when the VSC-HVDC system is reclosed to the fault cleared state. To verify the validity of the proposal
a five-terminal VSC-HVDC grid with the optimized fast reclosing strategy is built and simulated in PSCAD/EMTDC. The simulation results show the proposed fast reclosing strategy can effectively suppress the power fluctuation during the reclosing process
and can shorten the reclosing recovery time by more than 50%