High frequency and high amplitude inrush current will be generated in the process of switching capacitor bank of SF

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circuit breaker. Under the effect of both pre-breakdown a

rc ablation and post-arc mechanical wear

the switching erosion of the arc contact of SF

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circuit breaker will aggravate and affect its service life. Therefore

the switching erosion characteristics of arc contact of SF

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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.