Petrychenko A. Methods and means of limiting leakage currents to ground in power supply systems of iron ore mines

The object of research are electromagnetic processes of formation leakage currents to earth in combined networks of iron ore mines. The aim of the thesis is development methods and means of restrictions to normal level transient leakage currents to earth in the segments of combined electrical networks with voltage up to 1000 V in modern power supply systems of iron ore mines by compensation of capacitive leakage currents. Research methods: system analysis, general theory of electric circuits, methods of mathematical statistics, mathematical modeling, physical modeling. Theoretical results: for the first time obtained statistical characteristics of the electrical parameters of the distribution networks insulation in modern power supply systems of iron ore mines, which allows you to use the results as input for the development of new protective devices intended; for the first time proved system of protection against leakage of current to ground in combined electric networks with voltage up to 1000 V in modern power supply systems of iron ore mines, where the operating current used alternating current of low frequency, and the source of operating voltage with a measuring shunt connected to the network via a static compensating inductor and capacitive coupling filter configured to resonate at the operational and industrial frequency, which allows to increase the reliability of power supply and ensure the electrical safety of miners; developed a new method of measuring the capacitance of insulation phases combined electric networks, in contrast to the known, provides the proportional measurement function "operating current - capacitance network" and thereby allows you to perform with the necessary level of accuracy resonant tuning of the static compensating reactor over the entire operating range isolation capacitance combined electric networks; an improved method for automatic compensation of capacitive leakage currents to earth in combined electric networks with voltage up to 1000 V with the use of a static compensating reactor, which is manifested in its resonance tuning the capacitance of the middle of the established intervals of the isolation capacitance. Practical results: developed method of evaluation of the protective properties of protective devices against leakage currents to earth and the device automatically compensat capacitive leakage currents to earth, and in reactor proposed methods of protection and compensation capacitance insulation combined networks relative to the earth in a particular circuit solutions and the test samples. The degree of implementation: the research results transferred to the practical implementation to "Electrical protection" (Kharkiv); implemented at "Kryvyi Rih ore-mine combine"; implemented in the educational process of SIHE "Kryvyi Rih National University". The field of application - electrical engineering.