An Arc Squeeze Method for DC Interruption - Experiments and Analysis

Conventional air dc circuit breakers face the problems of complex arc motion control and arc back-commutation. In order to simplify the arc motion control, solve the arc back-commutation, and shorten the breaking time, this paper proposes an arc squeeze method, which stretches the arc in the insulating slit to make the arc voltage rise. The arc voltage acts as counter voltage to the system voltage and causes the current to cross zero, and then, current interruption is completed. For the experimental study, a test device was designed and made. The effects of different structural parameters (penetration depth of insulating plate, slit cross section circumference, and area) and external parameters (operating speed of insulating plate and peak circuit current) on the arc voltage increase during the breaking process were studied and analyzed. The interruption time of fault current with maximum value within 12-22 kA is quite short (about 5 ms).