Research on Optimization Design of Coal Mine Power Supply System Based on Mergers and Restructuring Background

In view of the expansion of mine production scale after mergers and restructuring and the existing problems in the original power supply system such as single power structure, insufficient transmission capability, limited main transformer capacity, and poor adaptability of downhole networks, etc, which have led to hidden dangers such as high risk of common cause failures, unstable power quality, excessive single-phase ground current and others, according to the principles of power system planning, a systematic transformation is implemented. A dual source independent power supply system is constructed, two 110 kV Xuangang substations are introduced for independent power supply, the transmission line cross-section is upgraded and OPGW fiber optic ground wire is installed; A new 35 kV main substation is constructed and equipped with a 16 000 kVA main transformer, greatly improving system redundancy and load bearing capacity. Meanwhile, SVG dynamic reactive power compensation device is configured to improve power factor, and automatic tuning arc suppression coil is adopted to suppress residual current of ground faults. Based on short-circuit current calculation, the reconstruction of downhole power supply network is completed. After the transformation, the system fully meets the N-1 operational requirements, with a stable power factor of over 0.98, the line voltage drop and ground fault current are significantly reduced, and the reliability and safety of power supply are fundamentally improved, providing solid power guarantee for large-scale production in mines.