Frequency considerations when employing travelling wave fault location algorithms

The difficulties associated with accurate fault location on transmission circuits is compounded by the uncertainties that exist in any of a number of significant parameters. These parameters are well understood for most impedance-based fault location techniques. However, travelling wave algorithms have commonly relied on the assumption that the modal velocity and line length are only significant in fault location. This paper considers the uncertainty in the precise signal travelling time, and the frequency response of the coupling equipment when applied to the two-ended travelling wave algorithm. Suitable signal processing techniques can be used to compensate for the filtering effects of coupling transducers. However, some notable uncertainty can remain in the calculated fault location.