The DC composite apparatus can transfer the short-circuit fault current from the vacuum transverse magnetic field (ETMF) switch to a paralleled circuit breaker or fuse for interruption

demonstrating promising application potential in DC distribution grid. For obtaining contact design of vacuum switch suitable for DC composite apparatus

in this paper the magnetic field distribution and arc stress in the arc gap of the 卍-type transverse magnetic contact under external transverse magnetic field (ETMF) are studied. The result

based on the finite element simulation method

shows that the 卍-type transverse magnetic contact and externally applied magnetic field after superposition can change the magnetic distribution characteristic around the arc. When the arc is at certain positions on the 卍-type contact

its stress characteristic is adverse for fast movement of arc towards the edge of the contact. While

the stress change of the arc

in case of passing over the 卍-type contact's slot

may make arc motion deflect

thereby prolonging its tabilization phase duration. The current commutation time of 卍-type contact and flat contact to the shunt fuse is tested. The conclusion that the average current commutation time of 卍-type contact is 0.3 ms longer than that of flat contact is obtained

which is in agreement with the simulation conclusion.