A Single-phase Grounding Fault Judgment Method Based on Steady-state Current Characteristics in Distribution

Abstract

In order to solve the problem of single-phase grounding fault judgment in non-solid-earthed distribution network, the power flow in non-solid-earthed distribution is analyzed. The steady-state current value in the upstream fault phase will be abruptly changed, and the current in the downstream fault phase will keep the load current constant. The steady-state current values in other non-faulty phases and non-faulty lines do not change abruptly. A single-phase grounding fault judgment method based on steady-state current characteristics is proposed. The power supply path real-time current matrix, the power supply path history current matrix, the power supply path mutation current matrix and the power supply path mutation current logical matrix are established. The problem of the single-phase grounding fault judgment is transformed into the matrix operation problem. The detailed calculation formulas are given. The simulation results show that the method proposed in this paper has a good adaptability to the permanent grounding fault and it is worth popularizing.