Research on 10 kV Power Supply System for Fully Mechanized Mining Faces

To address the contradiction between the growing power supply capacity demand of fully mechanized mining equipment and the insufficient power supply capacity of the existing 3.3 kV system, and to promote the safe application of the 10 kV power supply system underground coal mines, the Shangwan Mine 12404 fully mechanized mining face is taken as the research subject for a systematic analysis of the network topology and key equipment protection functions of the 10 kV power supply system. A component and distributed parameter model of the power supply system is established using Simulink, and a comparative study is conducted on the differences in key indicators such as single-phase ground fault current, touch voltage, power quality, and harmonic pollution between the direct power supply scheme and the scheme with an additional isolation substation. Simulation results indicate that in long-distance power supply scenarios, the limitations of the direct power supply scheme become more prominent: the longer the power supply distance, the more difficult it is for the voltage quality at the line terminals to meet standard requirements, and harmonic pollution intensifies accordingly; in the event of a single-phase ground fault, the touch voltage can reach up to 199 V, far exceeding the 36 V safety limit. The scheme with an additional isolation substation can effectively extend the power supply distance, control the touch voltage within the 36 V safety range, and simultaneously improve the terminal voltage quality and suppress harmonics. Aiming at the new electrical safety risks faced by 10 kV equipment in the complex underground mine environment, protection function upgrading measures are further proposed, including adding system-to-ground insulation monitoring, longitudinal differential protection, and iron core grounding protection, optimizing the setting basis for overload protection, and introducing enhanced safety technologies such as high-voltage live warning, power cutoff when the cover is opened, and dual local ground electrode monitoring. A full-process safety protection system covering protection functions and technical requirements is constructed, promoting the transformation of safety concepts from "passive protection" to "active prediction", and providing theoretical and technical support for the safe and stable operation of the 10 kV power supply system underground coal mines.