The Effects of Arc Protection of 10-kV Switchgear Based on the Principle of Voltage Latching up

The reasons of the no-action of conventional protection and arc protection based on current latching up criterion when phase-to-ground fault occurs in the internal of switchgear or external cable resulting in the increase of line voltage which causes switchgear ground discharging and damages with the further development of the fault are analysed in this paper based on the accidents of the 10-kV switchgear in the substation. Therefore, it is concluded that the switchgear should be tripped when single-phase grounding happens and accompanied by arc discharging. On the basis of it, a new type of 10-kV switchgear arc protection based on the principle of voltage latching up is proposed and compared with the arc protection based on the principle of the current latching up. The results demonstrate that the new voltage latching up arc protection has higher sensitivity than arc protection based on the conventional principle of the current latching up in the 10-kV switchgear.