Analysis on single-phase line break fault of 10kV non-grounded distribution network

Line break fault is becoming more and more frequent in 10kV neutral point non-grounded distribution system. This paper takes 10kV distribution line single-phase line break fault as the research object, analyzes the characteristics of electrical quantities when single-phase line break fault occurs, including single-phase line break without grounding point, single-phase line break with grounding at power supply side and single-phase line break with grounding at load side. Electrical quantities during single-phase line break fault are analyzed using symmetrical component method with sequence network and vector diagram, the variation of electrical quantities are summarized, and protection criterion for single-phase line break fault is proposed. Simulation results by PSCAD/EMTDC ensure the correctness of the analysis results and line break protection criterion.