Abstract：With the development of distribution network, large number of switchgears are coming into applied in the power system. Because of the own reasons of the equipments, operating environment and other factors , arc short-circuit fault of LV/MV buses often occurs, which causes a great threaten to the safety of operating personnel and the reliability of power system. Based on the analysis of the generation mechanism of the LV/MV internal arc fault, this text designs a new arc protection system which consists of ultrasonic detection module,over-current detection module,arc detection module,high speed earthing switch unit and logic processing module. This device not only can remind the operation and maintenance personnel to come to repair by the alarm signal before the occurrence of an arc fault, but also can extinguish the arc fault in a very short time (<5ms) and eventually clear the fault arc by the upstream circuit breaker, which greatly improves the reliability of LV/MV switchgear.
2014, Vol. 15 
