With the development of such new energy as wind power as well as DC power grid

the frequency of the breaking current of circuit breaker is diversified

which requires the circuit breaker can break the current higher or lower than 50 Hz. For this problem

the influence of current frequency on the breaking capacity of vacuum circuit breaker is studied from such three aspects as arcing process

magnetic field regulation and post-arc process in this paper. Firstly

the distribution of arc micro parameters at different frequencies is studied. It is found that with the increase of frequency

the arc configuration presents the phenomenon of agglomeration

and the contact presents the phenomenon of serious local ablation. However

the total ablation of the contact becomes smaller due to the shorter arcing time. The lower the frequency

the longer the arcing time

and the contacts show serious ablation. Then

the magnetic field distribution of cup-shaped longitudinal magnetic contacts under different frequencies is studied. It is found that with the increase of frequency

the more uneven the magnetic field distribution is

the less the diffusion effect on the arc plasma becomes

and the plasma is more difficult to diffuse due to the shortening of arcing time. Finally

it is found through the analysis of the influence of frequency on the growth process of back arc sheath that the greater the frequency

the slower the back arc sheath grows to the full opening distance

thus reducing the breaking capacity. It is concluded that the contact of the circuit breaker under low frequency is seriously ablated as a whole

and a large amount of metal vapor will be generated when the arc is extinguished. The attenuation process of metal vapor will dominate the post arc insulation recovery process of the circuit breaker

while the post arc insulation recovery process of the circuit breaker under high frequency is dominated by the sheath growth process.