High voltage transmission line protection principle using transient signals

Based on the concept of multi-resolution morphological gradient (MMG) in mathematical morphology, a new scheme of single-ended transient protection is proposed. On the basis of MMG, the window function energy spectrum of the transient current signal generated by the fault is extracted to realize the identification of faults in the area and outside. A typical 500 kV EHV transmission line is selected and simulated by PSCAD/EMTDC. The results show that the scheme is not affected by fault type, fault location, transition resistance and initial phase angle. At the same time, the calculation amount of the algorithm is smaller than that of the multi-scale wavelet transform, which is beneficial to engineering implementation.