Abstract: The compensation principle of arc suppression coil with three phases and five columns system is introduced in this paper. The structure of this arc suppression coil is different from the traditional model, and it is the integration of the traditional grounding transformer and arc suppression coil. The arc suppression coil with three phases and five columns system can realize automatic trace and compensation for grounded fault capacitive current of power network by the method of regulating inductive current of second winding with silicon controlled rectifier.