Adaptive Reclosing Strategy of Multi-port Inductively Coupled Current Limiting DC Circuit Breaker

HVDC power grid is the main carrier connecting renewable energy and AC main network. The post-DC fault recovery speed greatly impacts the stability of the whole AC/DC power grid. Based on multi-port inductively coupled high voltage DC current limiting circuit breaker, a fast reclosing strategy coordinating with converter control strategy of HVDC grid was proposed. Firstly, the topological structure of multi-port current limiting dc circuit breaker was briefly presented. Secondly, the influence of converter control strategy on DC voltage after fault isolation was analyzed. Thirdly, the reclosing sequence of current limiting circuit breaker was selected and the control strategy and logic flow of coordinated reclosing for converter-circuit breaker connected with such weak AC system as wind farm and so on were formed. Finally, in a simulation model of four-terminal bipolar HVDC grid it is verified that there is relatively lower impulse current in the proposed reclosing strategy and the failure recovery time is shorter.