Single ended travelling wave fault location scheme based on wavelet analysis

A novel single ended travelling wave fault location method that can estimate the fault location from the transient currents. It is based on the properties of travelling waves instigated on high voltage transmission lines as a result of a fault, switching operation, or a lightning strike. The method is unique in that superimposed voltage transients can be deduced from the transient currents without employing measurements taken from voltage transducers. Once both the transient currents and voltages are known then the incident and reflected waves at the substation can be calculated. Crosscorrelation of the incident and reflected waves then provides the fault location. The scheme described by D. W. P. Thomas et al. (see ibid.,2001) has proved very successful and provides fault locations within 500 m, but, in some circumstances there are ambiguous results. It will be shown in this paper that, through the use of wavelets, layers of results at different time (or distance) resolutions can be provided which helps identify the correct fault location.