Algorithm for ultra high speed travelling wave protection with accurate fault location

Basing fault generated current travelling wave, a novel algorithm implementing ultra high speed protection and fault location for transmission lines is proposed. By applying wavelet transform to the current travelling wave signals measured at two terminals of a protected line, the corresponding modal maxima of the two current signals are obtained. The algorithm uses the polarity relationship between two initial modal maxima to determine whether the fault is internal or not. Simultaneously, the fault location can be easily calculated according to the interval between the two modal maxima. The factors influencing on travelling wave protection and fault location are analyzed and some measures are presented. Extensive simulation results based on EMTDC demonstrate that the algorithm is able to achieve double functions of ultra high speed protection and highly accurate location, which is just required by EHV/UHV transmission systems.