Investigating on Synergy Effect of Series-Connected Vacuum Arcs in Multi-break VCBs

In this paper, the synergy effect of series-connected vacuum arcs in multi-break VCBs is firstly proposed, which is the interaction among the arc memory, current zero (CZ) characteristic and the post arc characteristic. The difference of the vacuum arc development in each break will affect the CZ characteristic and then affects the post arc dynamic voltage distribution (PDVD) and dynamic dielectric recovery strength (DDRS). According to the synergy effect, the target of the controlling methods such as the magnetic arc control, asynchronous cooperation, voltage-sharing measures and the magnetic arc blow is compared and discussed. The essential controlling methods should be applied in the arcing process which reduces the difference of each break while the externally compulsive methods such as grading capacitors are used to compulsively change the PDVD. The vacuum arc development and post arc characteristic are observed to analyze the synergy effect with different controlling methods. Finally, the future direction and application of the multi-break VCBs are discussed. The paper provides the reference of multi-break VCBs for application to high voltage, HVDC series-connected VCBs and pulsed power switchgear.