College of Mining, NUST MISIS, Moscow, Russia:

L. A. Plashchanskiy, Professor, Candidate of Engineering Sciences, pla3768@yandex.ru
M. Yu. Reshetnyak, Post-Graduate Student

Recently, the issue of reducing the cost of coal mining by underground method is quite acute due to significant fluctuations in coal prices on a global scale. Russia is one of coal exporters to the world market and ranks sixth in terms of supplies. The instability of prices on the world market of hydrocarbons, as well as the increase in the number of deposits with complex mining and geological conditions forces Russian and foreign coal mining companies to develop new technological and management solutions to reduce the cost of coal production. One of these solutions should be the increase in the level of power equipment in high-loaded faces of coal mines, which is due to the use of modern high-performance mechanized mining equipment. Currently, the majority of high-performance equipment in coal mines includes conversion devices in the control systems of electric drives of technological machines and installations. Operation of the converters is associated with significant generation of higher harmonics in the power supply network, which negatively affects the quality of electrical energy in underground networks of coal mines. In addition to the negative impact in the form of increased losses in the main elements of the underground network, higher harmonics also negatively affect the operating modes of the equipment, which worsens its performance. According to the results of experimental researches at step-down substations in high-performance coal mines, the coefficients of the n-th harmonic voltage components are obtained, that allow assessing their compliance with the quality parameters of electric energy. A significant deviation is found between the actual values of the total coefficient of the harmonic component and the state standard GOST 32144-2013 (for some step-down substations, the excess is 9.7 times), which negatively affects operation of the main process equipment both on ground surface and in underground mine. This article proposes an approach to the improvement of electric energy quality control in power grids of coal mines, including hazardous mines in terms of gas an and dust outbursts.

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