Assessment of operational reliability of power supply to developing ore mining areas at a high-altitude mine

Development of new deposits and modernization of existing mining enterprises in order to improve their efficiency are the priorities for the development of tungsten-molybdenum resource sector. In the modernization of mining productions, attention is paid to all technological processes and engineering systems, transformation of which should be aimed at improving economic performance, including reliability. Research of power supply systems of mining enterprises and modes of their operation is an urgent task, as this type of engineering support of mining works, auxiliary processes and facilities determines competitiveness of an enterprise as a whole. In the course of research, an assessment of operational reliability of power supply of developing ore mining areas at a high-altitude mine of the Tyrnyauz deposit (Kabardino-Balkaria) was performed. It was found that under the existing scheme of separate power supply of 6 kV networks from substations, the full ground fault currents for these networks are respectively: I030=17.5 A and I011b =12.2 A and reach the limiting values at which it was possible to disconnect them by disconnectors (the limiting current was 20 A). A formula for total ground-fault current in 6 kV underground networks was recommended. It was shown that reliability of power supply in the above mine, as well as the level of danger of electric shock in electrical installations depended largely on the number of singlephase ground faults. On the basis of the theoretical and experimental research, the solutions to improve the operation of electrical networks, taking into account the structure and modes of operation of a highaltitude mine were developed.