A Bus Differential Protection Method Based on Fault Component in DC Distribution Network

For flexible medium-voltage DC distribution network, this paper proposes a sample value differential bus protection based on fault component in DC distribution network. In this method, the current of each branch is sampled at the same time, and the fault component differential current of the sampled value is compared with the threshold value to discriminate the internal fault from the external fault. This method can avoid the influence of load current and has higher sensitivity. A three-terminal DC distribution grid based on MMC is built on the PSCAD platform. Extensive simulation results show that the proposed bus protection method works reliably and rapidly for different fault types.