PROCEDURE MEASURING RESISTANCE OF GROUNDING ELECTRODE AND DEVICE FOR ITS REALIZATION

摘要

FIELD: electrical engineering, measurement of resistance of grounding electrode in power networks with voltage up to 1000 V. SUBSTANCE: invention can find use in various services including small enterprises of any form of ownership which execute operational control over serviceability of electrical power equipment. Technical result of proposed invention lies in increased measurement precision of resistance of grounding electrode, in simplified procedure and its diminished cost, in simplified design and reduced cost of device that is used to conduct measurements. Above-mentioned technical result is achieved by supply of measured current to grounding electrode through water-cooled calibrated resistor directly from phase wire of electric network with voltage up to 1000 V. Value of current flowing through grounding electrode is found by resistance Rcr of water-cooled calibrated resistor and voltage Ucr across it as quotient of voltage by resistance. Value of voltage across grounding electrode is determined by phase voltage Uph of power network and voltage Ucr across calibrated resistor as difference between phase voltage and voltage across calibrated resistor. Sought-for resistance Rge of grounding electrode is found by following formula based on Ohm's law . Device for realization of procedure has voltmeter and connecting wires, water-cooled calibrated resistor and switch to switch water- cooled calibrated resistor in parallel to voltmeter which one terminal is connected to one of phase wires of power network and which other terminal is connected to grounding electrode. EFFECT: increased measurement precision of resistance of grounding electrode, simplified design and reduced manufacturing cost of device. 1 dwg