Discussion on Several Problems of Earthing Fault Protection in Distribution Network

Abstract

Power grid companies in China propose to quickly and closely isolate the earthing fault of distribution networks to reduce electric shock and large-scale blackout. However, there are great controversies on different earthing modes and the advantages and disadvantages of earthing fault protection methods for medium-voltage distribution network, and no consensus has been reached, which is not conducive to the formation of an optimized earthing fault disposal method. In this paper, experiences at home and abroad are summarized. Technical characteristics of different earthing modes and their earthing fault protection methods are compared. It is pointed out that the earthing mode will affect the detection standard of earthing fault and the statistical result of protection accuracy. The problems existing in the conversion of low current grounding system to low resistance grounding, arc suppression coil parallel low resistance grounding and active intervention arc suppression are analyzed. Transient earthing protection technology and its application are introduced. For different types of distribution network, the selection of earthing mode and earthing protection method is suggested.