Abstract: Due to the change of the ground parameters of the distribution network after the single-phase

grounding fault，the traditional active arc suppression method based on the ground parameters in the normal

operation state has a deviation between the compensation current reference value and the actual value. In

consideration of the problem that the fault residual current cannot be fully compensated，which leads to difficulty in arc extinguishing，the characteristic frequency current signal was injected into the distribution network through the active arc suppression device connected to the neutral point，to eliminate the influence of the system frequency on the measurement accuracy of the equivalent parameters to the ground of the distribution network. By constructing a characteristic signal circulation loop，the measurement of the equivalent parameters to the ground of the distribution network after ground fault was realized. Then，according to the real-time measured ground parameters and zerosequence voltage，the compensation current was dynamically calculated，and the active arc suppression device was controlled to inject current into the neutral point to realize the fault arc suppression. And the method of injecting zero-sequence current was proposed to obtain the amplitude and phase of the faulted phase voltage which can be used to detect the faulted phase. Finally，it is verified in PSCAD/EMTDC that the proposed method can reflect the changes of ground parameters of the distribution network in real time，realize full compensation of fault branch  current，and achieve the purpose of rapid arc extinguishing of ground faults in distribution network.

    Key words: distribution network；single-phase grounding fault；measurement of ground parameters；active arc

suppression；fault phase selection；dynamic compensation