Aimed at problem of difficulty in extracting precision of arrival time from wave arrival at bus bar in travelling wave ranging

the intrinsic time-scale decomposition（ ITD） principle is proposed to extract the timefrequency information of the travelling wave. The complete time-frequency distribution of the original signal is obtained by utilizing ITD to decompose the fault traveling wave signal adaptively

so that the accurate time for wave arrival at the bus bar can be obtained. Aiming at the problem that the traveling wave velocity is difficult to be accurately determined

a distance measuring method which is not affected by traveling wave velocity is proposed by using the A-type and the D-type distance measuring methods

so as to overcome the error between the presetted wave speed and the actual wave speed to improve the measurement precision. Simulation results show that the combination of these two algorithms is effective

and the error pre-cision is better than D-type method. To some extent

it can improve precision of fault location.