Abstract: In the 10 kV distribution network electric power system, the power supply radius of the distribution wire is such long and there are many branch structures, which causes great trouble to the line fault inspection and elimination. In addition, in response to the further improvement of the reliability of the power supply of the city network, the operation of the live-line working has been widely concerned. How to digitally enable the distribution network to quickly and accurately locate the fault so as to realize the live-line working needs to be solved urgently. Based on the above problems, this paper adopts a single-ended fault impedance location algorithm based on differential equation to eliminate the transition resistance of the fault point based on the real-time sampling signal of the voltage and current of the novel transient filter device and considering the operation mode of the distribution network. Based on the above algorithm, the new transient filter device is digitally enabled, and the installation method and installation guideline are guided. Finally, the new transient filter device is installed in the overhead line by the way of live operation, and the practical application results are given. The results show that the fault can be accurately located within 20% by the new transient filter device installed on the 10 kV overhead line, the fault inspection time is greatly shortened, and the power reliability of the 10 kV distribution network is effectively improved.