Equivalent circuit for mine power distribution systems for the analysis of insulation leakage current

Successful mining businesses rely heavily on the safety and reliability of their mine power distribution systems. Mine power distribution systems are designed to withstand an aggressive environment with a range of hazards. The harsh operating conditions require improvement to personnel protection systems through the study and simulation of the electric network’s normal and emergency operations. The purpose of this study is to assess insulation leakage current using an equivalent circuit of a mine power distribution system. The simulation identified the key properties of the equivalent circuit which can model potential hazardous situations. We also selected the quantitative metrics and the equivalent circuit property ranges. In order to simulate the transients, we recommended using the time constants for the oscillation damping in circuits, the insulation phase resistance properties, and the absorption currents. This paper presents the equations to estimate these values. As an example, we considered the equivalent circuit of a mine power distribution system with an R-L filter in the residual current device line. The equivalent circuit helps analyze the current leakage when a person touches a live phase conductor accounting for low-frequency polarization in the phase insulation. The proposed approach to the simulation and analysis of the insulation current makes it possible to generate an equivalent circuit of the mine power distribution system to analyze phase voltage asymmetry, trip currents of residual current devices, low-frequency polarization of the insulation, and the leakage current effects on the human body.