Abstract: Peterson coil has not achieved excellent arc-suppression performance due to increased harmonic and active component of fault current with the expansion and development of distribution network. To address the problem, a flexible arc-suppression device based on the three-phase cascaded H-bridge converter has been proposed. This paper presents an interconnection strategy for the above arc-suppression device in order to further improve the reliability and utilization of the device. When the device has a partial failure, it makes three phase of device interconnected, which maintain the arc-suppression function. A control strategy based on finite control set model predictive control is proposed to achieve stable arc-suppression control before and after devices are interconnected. Simulation results show that proposed method can significantly increase fault-tolerant ability of the device and always maintain the stability of control.