Abstract：The three-core underground cable in the distribution network works in a harsh environment. Due to

the influence of aging，external force，high temperature and humidity，the insulation of long-term live operation is

easily damaged and causes faults. Aiming at the single-phase grounding fault of cable in distribution network，a

fault location method based on the refraction-reflection characteristics of traveling wave head was proposed.

Firstly，the zero-mode voltage of each line was obtained，and the arrival time of the wave head was determined. The waveform in a power frequency period after the arrival of the wave head was selected，and the main frequency of the wave head was determined. The square wave with the same frequency as the main frequency of the wave head was selected as the initial traveling wave signal，and the attenuation signal waveform at the head and end of the initial traveling wave signal after refraction of different times at this frequency was calculated. If the correlation

between the corresponding data of the waveform calculated at both ends met the requirements，it was assumed that the fault point is the actual fault point. Otherwise，continue to narrow the fault interval until the correlation between the waveform data is satisfied. Simulation results show that the method can quickly and accurately realize fault distance measurement，reduce the complexity of fault distance measurement，and has strong effectiveness and practicability.

      Key words：distribution cables；fault distance measurement；waveform similarity；wavehead refraction

reflection