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

摘要

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.