Auto-Reclosing Strategy for Mechanical DCCB with Current Commutation Drive Circuit

For high voltage multi-terminal direct current (MTDC) system using overhead lines for power transmission, such as Zhangbei demonstration project, mechanical direct current circuit breakers (DCCB) with current commutation drive circuit (CCDC) are used to deal with short-circuit DC faults. Considering most of the short-circuit faults occurring to overhead lines are temporary, mechanical DCCB should be capable of auto-reclosing, and this paper is aimed to realize its auto-reclosing function without overcurrent and overvoltage. In this paper, the topology and working principle of mechanical DCCB with CCDC is presented first. Then, the auto-reclosing strategy for mechanical DCCB with CCDC is proposed. By using this auto-reclosing strategy, the permanent fault and the temporary fault could be easily distinguished, and no overcurrent and overvoltage, which might cause damage to vulnerable devices in converters, are produced. In the end, simulation model in PSCAD is established to verify this auto-reclosing strategy.