Breakdown process of a rod-to-plane gap in atmospheric air under DC voltage stress

Discharge phenomena were observed under chopped or steady state DC voltage application. A still camera and two photomultipliers were used to record and measure the development of the electrical breakdown in a normal air gap. The breakdown process under both positive and negative DC voltage stress differs from that under impulse voltage. In the case of DC voltage, space charge is produced by corona discharges prior to the complete breakdown, which affects the breakdown process significantly