Erosion of Cu–W contact material of SF₆ circuit breakers when making capacitor bank

Abstract

For an SF 6 circuit breaker in capacitor bank-making operation, the inrush current may cause serious erosion to its arcing contacts. In order to observe the characteristics of this erosion, an arc extinguish chamber of SF 6 circuit breaker with Cu-W arcing contacts was designed, and experiments of capacitor bank making were carried out. The prebreakdown arcing duration and inrush current were measured, and the mass loss of the contact after 100 times of operation was calculated. Power-frequency-withstanding voltage was measured after every 20 operations. The surface status, scanning electron microscope (SEM), and energy dispersive x-ray spectroscopy (EDS) of the contact material were recorded. The characteristics and mechanism of arcing contact erosion in SF 6 circuit breaker in the making process were then analyzed. Compared to the case of breaking high current, this analysis found two major mechanisms that lead to severe arcing contact erosion in the case of capacitor bank making operation, namely, the arc erosion due to prebreakdown current and the erosion of arc heated contact due to friction. The erosion after contact caused by mechanical friction occupies a relatively larger proportion in the mass loss of contact materials. Under the conditions of 3 m/s making velocity, 18 kA current peak, and less than 2 ms arcing duration, the mechanical wear mass loss rate is greater than 1.0 mg/C.

A molecular dynamics simulation study on the role of graphene in enhancing the arc erosion resistance of Cu metal matrix

“…Surface morphology, which can be evaluated from various imaging technologies, is typically used to study the impact of arc erosion on the contact surface [31,61]. A similar evaluation was conducted with both pure Cu and Gr-Cu systems by comparing the sizes of the erosion craters and the surface morphologies.…”

Arc erosion characteristics evolution of Ag/Ti3SiC2 composites during repetitive arc breakdowns in SF6 gaseous medium

“…In the service process of electric contact materials, arc discharges between the mating electrodes are inevitable, which will greatly affect the performance of the electric contact materials 3 . Since sulfur hexafluoride (SF 6 ) gas possesses great insulating property and arc quenching performance, SF 6 gas is employed as the conventional insulating gaseous medium in power switching devices 4,5 . Therefore, it is vital to study the arc erosion properties of electrical contact materials in SF 6 gaseous medium.…”

Inspección del desgaste en contactos eléctricos usando segmentación por instancias

“…En un estudio sobre la erosión por fricción en los contactos eléctricos en materiales de Cobre (Cu) y Wolframio (W) en interruptores automáticos, Ding [4] realiza una medición sobre la pérdida de masa en gramos después de alrededor de 100 operaciones de apertura y cierre de circuito, la medición se realiza a través de una balanza electrónica. Además, se entregan visualizaciones de los efectos de la corriente eléctrica sobre las superficies, utilizando un microscopio electrónico de barrido (SEM).…”