Research on a line protection method for DC distribution system based on parameter identification

A DC distribution line protection method based on parameter identification is proposed. The parameter equation in the conditions of monopolar grounding fault and pole-to-pole fault is deduced by analyzing DC distribution line faults, the protection scheme for DC distribution line is researched based on the principle of parameter identification. The protection scheme utilizes the voltage and current information at protection installation position, fault distance and transition resistance are calculated by method of the least square. The distinction of fault section and determination of fault position are achieved by comparing fault distance with corresponding line length. The model of DC distribution system is built on the real time simulation platform RT-LAB. Numerous tests are carried out on different transition resistances and fault positions, different line types of DC distribution line fault. Simulation results show that the line protection scheme for DC distribution system based on parameter identification is effective.