Experimental Study on Flashover Performance of Hot Sticks under Switching Impulses

The hot stick is commonly used in live-line work, and its flashover performance is one of the critical issues since this is related to the worker safety. However, several critical parameters during the flashover are not well understood. To do this, an experimental platform was established for the flashover performance study, with which the applied voltage, discharge current and high-speed frames were recorded simultaneously. Experiments on a 6-m hot stick were carried out under switching impulses with different polarities and magnitudes. Deviations of breakdown voltage are analyzed first. The characteristics of leader development under positive and negative impulses are then compared according to the corresponding current waveforms and high-speed frames. Judging from the number, location and span of leader channel jumps, eight types of discharge path are classified, and the effect of impulse polarity and amplitude are analyzed. For both positive and negative flashovers, significant ablation damage zones were observed in the ground terminal of the hot stick.