Protection Scheme of Multi-terminal Flexible DC Distribution Network Based on Current-Limiting Inductor Voltage

Abstract

The rapid development of power electronic devices has promoted the rapid development of multi-terminal flexible DC distribution networks, indicating the direction of DC technology and urban power distribution systems. However, there are several technical problems in multi-terminal flexible DC distribution network that still need to be solved. In relay protection, the main difficulty faced by DC distribution network is the rapid and reliable identification of DC faults. This paper proposes a multi-terminal flexible DC distribution network protection scheme based on current-limiting inductor. First, the system configuration of the multi-terminal flexible DC distribution network is introduced. Then, the DC-side fault characteristic of the flexible DC distribution network are analysed. Based on this, a protection scheme based on current-limiting inductor voltage is proposed. Next, a complete protection scheme is designed. Finally, the proposed protection scheme is verified by real time digital simulator (RTDS). The simulation results show that the scheme is not affected by the fault resistance and fault distance.