Application of DC resistance tester in circuit resistance measurement of relay protection device in substation

Relay protection devices are a crucial component for the safe and stable operation of the power system. By measuring circuit resistance, it can be ensured that relay protection devices can act quickly and accurately in the event of a fault, thereby effectively protecting the security of the power system. This paper analyzes the structure and impact of the circuit resistance in substation relay protection devices, expounds on the technical characteristics and operational essentials of the DC resistance tester. Through actual testing, the error of the DC resistance tester is controlled within ±0.5%, confirming the high accuracy of the DC resistance tester in measuring circuit resistance across different resistance ranges in relay protection devices. Through application analysis, this paper aims to provide reliable technical support for the maintenance and repair of substation relay protection devices.