The invention provides a
coal mine
grid system insulation state monitoring method and belongs to an electrical power
system feed line insulation state monitoring method. A
feed line branch circuit is selected for doing single-phase
longitude metal grounding experiment, zero sequence
voltage of a
bus and zero sequence current of a non-malfunction
branch circuit are tested, zero sequence impedance of the non-malfunction
branch circuit is obtained, namely,
insulation resistance and ground
capacitance, for obtaining insulation parameters of all circuits, another branch circuit is reselected to do a single-phase connection
low resistance ground experiment or the next circuit with the non-branch-circuit number 1 is waited for generating single-phase ground malfunction, the experiment is repeated, insulation parameters of a first experiment malfunction circuit are obtained, and the insulation parameters of all
feed line branch circuits are obtained by synthesizing results of the two experiments. The
coal mine
grid system insulation state monitoring method has the advantages that insulation degradation degree of the circuits is analyzed from state change of the
bus zero sequence
voltage and an
arc suppression coil, the zero sequence
voltage changes to a certain extent, switching-in situations of damping resistance change, and the degradation degree of circuit insulation is forecasted by monitoring change of transient states of a plurality of feature quantities.