Методи та засоби обмеження струмів витоку на землю в системах електропостачання залізорудних шахт

Abstract

The thesis is devoted to increase functioning efficiency of protection devices in the direction of minimize false shut-offs of electric consumers and improve electrical safety in combined electrical networks with voltage up to 1000 V power supply systems of iron ore mines (CEN). Proved necessity of the developing new protection devices against leakage current to ground in the CEN, which performs control of the impedance network isolation and leakage current by means of alternating operational current. Presents the results of development direct proportional measuring function of protection devices which working on alternating current in the operational conditions of the CEN. An improved method and designed automatic compensation controller of capacitive leakage currents by applying a static compensating reactor and its configuration on the capacity of the middle of the established intervals of the operating range isolation capacitance of the CEN which allows to limit short-time leakage currents to earth to normalized level. Developed a new method of measuring isolation capacitance of the CEN with direct proportional measuring function "operational current – isolation capacitance" and made the choice of the optimal frequency of the alternating operating current, which enables resonant tuning of the static compensating reactor with sufficient level of accuracy.