Post-arc currents of vacuum interrupters with axial magnetic fieldcontacts under high current and voltage stress

摘要

The post-arc current of vacuum interrupter units with bipolaraxial magnetic field contacts has been investigated under conditions ofhigh current (40 to 60 kA RMS) and high steepness of the transientrecovery voltage (5 and 10 kV/μs). The arcing time and contactdistance, respectively, has been changed by varying the moment ofcontact separation. By comparison with simulations, the measured cleardecrease of the post-arc current and charge with decreasing arcing timecan be attributed to lower residual ionization. The dependence of thepost-arc current on du/dt is explained by the influence of secondaryemission