Open AccessMethod to improve the repeatability of dynamic contact resistance measurement test results for high‐voltage circuit breakers
Author(s) -
Cheng Tingting,
Gao Wensheng,
Zhao Dongbo,
Huang Yulong,
Liu Weidong,
Zhao Yuming
Publication year - 2019
Publication title -
iet science, measurement and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.418
H-Index - 49
eISSN - 1751-8830
pISSN - 1751-8822
DOI - 10.1049/iet-smt.2018.5486
Subject(s) - repeatability , circuit breaker , voltage , contact resistance , fuse (electrical) , electrical engineering , materials science , transient recovery voltage , electronic engineering , engineering , mathematics , statistics , composite material , constant power circuit , power factor , layer (electronics)
Dynamic contact resistance measurement (DRM) is an effective technique to evaluate the contact condition in substations without dismantling circuit breakers. However, performing DRM tests with unsuitable test parameters will cause low repeatability of the test results, and even lead to the misdiagnosis of contact condition. Performing the DRM tests at high DC injected current can improve the repeatability. This paper studies the mechanism of the DC injected current on the repeatability of the DRM test results, and it also promotes a new determination method of the DC injected current amplitude. The impact of the DC injected current on DRM test results is reviewed. The mechanism of the DC injected current on DRM test results is investigated by analysing the chemical composition of the contact surface, the force exerted on the contacts, and the temperatures of a‐spots on the contacts’ surface. Results indicate that not the Lorentz force, but the temperature of a‐spots is the primary influencing factor. The amplitude of the DC injected current can be determined by calculating the temperatures of the a‐spot on the contacts’ surface. And this method can also be used for other SF 6 circuit breakers.