Full current compensation arc suppression coil can solve the compensation problem of resistive current and harmonic current components in residual current, also can suppress the arc-earthing over-voltage effectively, and ensure power supply security and reliability in distribution network, so it has a wide application prospect. Based on the principle, structure and research status of full current compensation arc suppression coil, the imperfections on full current compensation arc suppression coil research and the technology questions on residual current compensation are summarized. It points out that zero sequence voltage is regarded as a measure and analysis object is advantageous to residual current compensation. The control strategies of full current compensation arc suppression coil are put forward and the necessity of capacity increasing transformation is elaborated.