Development Process of Discharges in Long Air Gaps Containing a Floating Conductor Under Positive Switching Impulses
The combined air gap for live-line work is a typical long air gap containing a floating conductor. The discharge mechanism of long air gaps containing a floating conductor is the fundamental theory for improving the safety of live-line work. In this paper, an observation platform of long air gaps containing a floating conductor with a configuration of the rod-rod-plane gap was established. The discharge observation tests of air gaps with the floating conductor at different po-sitions were carried out. The data of the applied voltage, the high potential discharge current, and the discharge optical images were obtained to study the discharge development process. The results show that the discharges in the two sub-gaps of a long air gap containing a floating conductor proceed simultaneously and interact with each other, with the discharge in sub-gap 1 consisting mainly of the downward leader-corona region and the upward streamer, and the dis-charge in sub-gap 2 consisting mainly of the leader-streamer region. The position of the floating conductor affects the inception instant of each stage of the discharge development and the time of discharge development. When the floating conductor is in any position, the discharge starts from sub-gap 1 and the discharge in sub-gap 2 starts before the break-down of sub-gap 1, and the breakdown of sub-gap 2 is not earlier than the breakdown of sub-gap 1. The critical charge required for the streamer-leader transition in sub-gap 1 is 0.26 μC, which is similar to long air gaps. The discharge devel-opment characteristics such as pre-discharge current amplitude and leader development speed differ from those of long air gaps.
live-line workfloating conductorlong air gapsdischarge development processpositive switching impulse
万方数据
维普
