The compensation current of the arc suppressing coil makes the phase angle and amplitude of the zero sequence measurement current of the earthed fault feeder vary greatly， and thus increases the difficulty of the detecting single-phase-to-ground fault feeder even more. On the basis of detailed analysis of the zero sequence measurement current distribution in the arc suppressing coil earthed power system， a new detecting one-phase-to-ground fault feeder algorithm is proposed. The algorithm adds the arc suppressing coil compensation current to the zero sequence current of every feeder in steady-state computations in power systems. The EMTP simulations and analyses show the algorithm proposed has effectively reinforced the protecting abundant degree. The operation results of actual power systems indicate the device based on the algorithm has a high accuracy in detecting the fault feeder in compensation networks.