NUST MISIS , Moscow, Russia:

L. A. Plashchanskiy, Professor, Candidate of Engineering Sciences, pla3768@yandex.ru
M. Yu. Reshetnyak, Assistant

The publication presents the results of research into occurrence conditions of resonance phenomena in underground power supply systems of coal mines. These studies are due to significant losses of electricity in the underground electrical networks of coal mines owing to resonance phenomena. In terms of unfailing performance and overall reliability for consumers, including high-productivity coal mines and the whole power supply system, the resonance phenomena pose a significant danger and, therefore, must be damped. The main technological unit which governs the stable operation of a coal mine is an extraction site, which is in spotlight in this article. An equivalent circuit is created for the power supply system of an extraction site was developed, including the equivalent circuits for the main process equipment: a shearer, an armored face conveyor, a crusher and a reloader, which are the sources of harmonic components and aid the resonance phenomena. After some transformations, a simplified equivalent circuit was obtained to assess the resonance phenomena of currents and voltages in underground electrical networks, and some dependencies were revealed to determine the conditions for their occurrence, and most importantly, to find the possibility of their damping in underground electrical networks. The implemented research allows determining a number of aspects that form the network topology and the structure of the underground power supply system, which makes it possible to: exclude the possibility of resonance; reduce power losses and extra heating of electrical equipment. This can have a beneficial effect on the safe operation of the power supply systems, reduce downtime, and, consequently, cut down the cost of coal mining.

1. Plakitkina L. S., Plakitkin Yu. A., Dyachenko K. I. Analysis and forecasts of coal mining and consumption in the world’s leading coal-producing countries in 2000–2035. Gornyi Zhurnal. 2018. No. 3. pp. 4–9. DOI: 10.17580/gzh.2018.03.01
2. Kopylov K. N., Kubrin S. S., Reshetnyak S. N. Improvement of energy efficiency and safety in coal longwalls. Gornyi Zhurnal. 2019. No. 4. pp. 85–89. DOI: 10.17580/gzh.2019.04.19
3. Kopylov K. N., Kubrin S. S., Zakorshmennyi I. M., Reshetnyak S. N. Reserves of increase of efficiency of coal extraction sections of coal mines. Ugol. 2019. No. 3. pp. 46–49.
4. Reshetnyak S., Bondarenko A. Analysis of Technological Performance of the Extraction Area of the Coal Mine. III International Innovative Mining Symposium. 2018. E3S Web of Conferences. 2018. Vol. 41. 01014. DOI: 10.1051/e3sconf/20184101014
5. Kubrin S. S., Reshetnyak S. N., Bondarenko A. M. Impact of technology factors on specific power demands of equipment in extraction districts of coal mines. GIAB. 2020. No. 2. pp. 161–170.
6. Plashchanskiy L. A., Reshetnyak M. Yu. High-performance coal mining shearer loader electromechanical systems. Energobezopasnost i energosberezhenie. 2019. No. 3. pp. 17–21.
7. Reshetnyak M. Yu. Harmonic composition study in electrical networks of surface complex of highperformance coal mine. Elektrotekhnicheskie i informatsionnye kompleksy i sistemy. 2019. Vol. 15, No. 4. pp. 61–67.
8. Plashchanskiy L. A., Zaripov Sh. U. Effect of high harmonics on performance of electric mains. Izvestiya vuzov. Gornyi zhurnal. 2010. No. 2. pp. 61–66.
9. Rönnberg S., Bollen M. Power quality issues in the electric power system of the future. The Electricity Journal. 2016. Vol. 29, Iss. 10. pp. 49–61.
10. Meyer J., Domagk M., Kirchner L., Malekian K., Safargholi F. et al. Survey on International Practice of Calculating Harmonic Current Emi ssion Limits. Proceedings of the 17^th International Conference on Harmonics and Quality of Power. Belo Horizonte, 2016. pp. 539–544.
11. Yang Y., Zhou K., Blaabjerg F. Analysis of Dead-time Harmonics in Single-phase Transformerless Fullbridge PV Inverters. 2018 IEEE Applied Power Electronics Conference and Exposition. San Antonio, 2018. pp. 1310–1315.
12. Litrán S. P., Salmerón P. Electromagnetic compatibility analysis of a control strategy for a hybrid active filter. Electric Power Systems Research. 2017. Vol. 144. pp. 81–88.
13. Shevyrev Yu. V., Shevyreva N. Yu. Improvement of voltagewaveform in power supply systems with dynamic rectifier in mineral mining and processing industry. Gornyi Zhurnal. 2019. No. 1. pp. 66–69. DOI: 10.17580/gzh.2019.01.14
14. Kartashev I. I., Tuls kiy V. N., Shamonov R. G., Sharov Yu. V., Nasyrov R. R. Quality management of electric power. 3rd enlarged and revised edition. Moscow : ID MEI, 2017. 347 p.
15. Zhezhelenko I. V. High harmonics in industrial power supply. 5^th enlarged and revised edition. Moscow : Energoatomizdat, 2004. 358 p.
16. Zhezhelenko I. V., Shidlovskiy A. K., Pivnyak G. G., Saenko Yu. L., Noyberger N. A. Electromagnetic compatibility of consumers. Moscow : Mashinostroenie, 2012. 349 p.