The fault point is found difficultly by using the fault location based on the one-terminal method or twoterminal traveling wave method when the single phase-to-ground fault occurs in tree type distribution network.Two-terminal method is used to determine the mapping of the fault point in the trunk line

then that the fault is located in the trunk line or in the branch line is judged. For the fault occurs in trunk line

the fault point is located in the mapping position;when the fault occurs in branch line

combined with the fault distance information of mapping position

the zero-mode wave velocity extraction algorithm is proposed based on location method of the gap between zero-mode and aerial-mode traveling wave propagation time. However

the amplitude attenuation and the phase variation of zero-mode traveling wave are obvious in different scales of the wavelet decomposition

which will result in the error of extracted zero-mode wave velocity is different.In order to improve location accuracy of branch lines

the paper analyzes the relationship between extracted zero-mode wave velocity and zero-mode wave velocity detected in busbar

based on that the method used to select the most precision location results is proposed.Using simulation model built by PSCAD/EMTDC to simulate different fault conditions

the simulation results indicate that the method is effective and has high accuracy.