The method of selective determination of the outgoing line with a single-phase earth fault in distribution networks with a voltage of 6-35 kV

摘要

FIELD: electricity.SUBSTANCE: method consists in fixing the earth fault moment, additionally connecting a sinusoidal voltage source of variable frequency above 50 Hz to the busbars of the switchgear supplying the power lines, changing the frequency of the additional sinusoidal voltage source to the moment of voltage resonance, measuring the current value using high-frequency current sensors at the moment of voltage resonance, comparing the values of the measured high-frequency currents of the outgoing lines, and identifying the outgoing line with a single-phase earth fault. Wherein the current value at the resonance frequency in the damaged outgoing power line is several orders of magnitude greater than the current on the outgoing power line without an earth fault. The method can be implemented on the basis of known microprocessor devices.EFFECT: reliable identification of a damaged line among other network lines, allowing to create the selective protection of electrical networks against single-phase earth fault in distribution networks with the voltage of 6-35 kV with isolated or resonantly compensated neutral.4 dwg