Research on Algorithm for Single-Phase-to-Earth Fault Section Location in Medium Voltage Distribution

Due to the large amount of branches and high grounding resistance of distribution grid, the grounding fault location has not been solved effectively. This paper proposes a Matrix-based live location method for single-phase-to-earth fault section in medium voltage distribution grid. Fault message character matrix is designed according to data measured by FTU. For neutral point insulation systems, the element of character matrix is the phase difference between zero-sequence voltage and zero-sequence current measured by FTU. For neutral point grounded by arc-suppression coil systems, the element of character matrix is the variant of zero-sequence-current measured by FTU using the theory of remnant current increment. Through analysis to character matrix using united criterion, fault section is determined and the solution is analyzed when fault information is not completed. The correctness and feasibility of this technology has been fully approved by site experiments.