Modularization design methodology for high-voltage mechanical DC circuit breaker with current commutation drive circuit

With rated voltage of multi-terminal direct current (MTDC) power transmission system varying from +/- 160 kV to +/- 500 kV and even +/- 800 kV, high-voltage direct current circuit breaker (DCCB) is in urgent demand. With remarkable features of low operating losses, free-maintenance, and relative small investment, DCCBs based on mechanical vacuum switch (MVS) and current commutation drive circuit (CCDC) are recognized to have bright prospects in practical engineering. However, parameters design and serial topology selection for high-voltage mechanical DCCB with CCDC are still open problems. Motived by this, parameter design method for a modularized DCCB with CCDC is proposed. Then, parameters of 500 kV DCCBs with two typical serial topologies, namely, modularized serial topology and integrated serial topology, are optimized, and simulations are conducted in PSCAD/EMTDC for verification. In the end, performances of the two serial topologies, including dynamic voltage balancing, fault-tolerance capability and cost, are discussed. According to research results, modularized design methodology is recommended for high-voltage DCCB with CCDC.