SF₆断路器弧触头关合侵蚀特性研究

High frequency and high amplitude inrush current will be generated in the process of switching capacitor bank of SF6 circuit breaker. Under the effect of both pre-breakdown arc ablation and post-arc mechanical wear，the switching erosion of the arc contact of SF6 circuit breaker will aggravate and affect its service life. Therefore，the switching erosion characteristics of arc contact of SF6 circuit breaker are studied in depth in this paper. Arcing experiments and making inrush current experiments are performed based on the equal charge method，and the contact erosion morphology，pre-breakdown arcing time，contact resistance and mass loss are obtained. The simulation model is set up according to the operating conditions of the arc contact，and the temperature field variation and contact collision process of the moving and stationary arc contacts are analyzed. The results show that the post-arc mechanical wear is an important part of the making erosion of the arc contact. With the increase of the peak value of the inrush current，the proportion of mechanical wear increases. When the inrush current is 15 kA，the mass loss due to mechanical wear accounts for 32.25% of the total mass loss. Under the ablation of pre-breakdown arc，the performance of contact material changes，and the contact surface becomes rough. After contact of the arcing contact，the mechanical wear of the contact is aggravated due to the change of material physical parameters. In case of next making operation of circuit breaker，the prior erosion makes the contact gap easier to breakdown and the ablation time becomes longer，thus making the mechanical wear more serious.