Fault Analysis of Multi-terminal DC Distribution System and Parameter Coordination of Protection Equipment

DC circuit breaker is an effective way to isolate faults on the DC line. However, it cannot always meet the system requirements limited by the manufacture ability. DC current limiting reactor can reduce the fault current to within interruption capability of the DC circuit breakers (DCCB). Therefore, the parameter matching of DC current limiter and DC circuit breaker is of great significance to the reliability and stability of the system. However, there are no uniform standards for the parameter selection of DC current limiters at present. This paper analyzes the pole-to-pole fault and calculates the fault currents in a three-terminal radiation network, which provides a basis for the protection. And the parameter value calculation is based on the typical case of medium voltage. A Three-ended DC distributed system is built in MATLAB to verify the correctness of the design method by simulation.