METHOD FOR MONITORING INSULATION STATE OF HIGH-VOLTAGE POWER GRID OF COAL MINE

摘要

A method for monitoring an insulation state of a high-voltage power grid of a coal mine relates to a method for monitoring an insulation state of a feeder line of a power system. A feed line branch circuit is selected for doing a single-phase longitude metal grounding experiment, a zero sequence voltage of a bus and a zero sequence current of a non-malfunction branch circuit are tested, and zero sequence impedance of the non-malfunction branch circuit is obtained, that is, insulation resistance and ground capacitance. To obtain insulation parameters of all circuits, it is required to select another branch circuit to do a single-phase connection low resistance ground experiment or wait for generating a single-phase ground malfunction of a next circuit with the non-branch-circuit number 1. The experiment is repeated, insulation parameters of a malfunction circuit for a first experiment are obtained, and insulation parameters of all feed line branch circuits are obtained by combining results of the two experiments. Advantages are as follows: in the p resent invention, the insulation degradation degree of the circuits is analyzed based on state changes of the bus zero sequence voltage and an arc suppression coil, the zero sequence voltage changes to a certain extent, the connection situation of damping resistance changes, and the degradation degree of circuit insulation is forecasted by monitoring changes of transient states of a plurality of feature quantities.