Research on influence of the magnetic arc blow in multi-break vacuum circuit breakers

The paper aims to investigate the influence of the interactive magnetic field in multi-break vacuum circuit breakers (VCBs) on the arc plasma and the post-arc characteristic. The magnetic field of multi-break VCBs is asymmetric and off-center because of the interactive magnetic field, which can be called bias magnetic field (BMF). The BMF distribution of double-break VCBs is gained by electromagnetic analysis. The test circuit of the magnetic arc blow in multi-break VCBs is established by simplifying as the interaction between the vacuum arc and the BMF. The influence of the magnetic arc blow on the arc plasma is studied by the high-speed CMOS while the relationship between the post-arc dynamic dielectric recovery and the magnetic arc blow is obtained by the measurement of the post-arc current. The results indicate that the influence of the magnetic arc blow on the vacuum arc and post-arc dynamic dielectric recovery with TMF contacts is larger than that of AMF contacts. The vacuum arc with TMF contacts bends to the opposite direction of Ampere force when the BMF is below 100mT and the post-arc charge obviously varies from 9μC to 50μC. Therefore, the paper can provide the base of construct and configuration to avoid the influence of the magnetic arc blow.