Study on non-unit transient protection principle for EHV transmission lines based on wavelet singular entropy

A new scheme of non-unit transient protection based on the concept of wavelet entropy is suggested. Combined with the technique of wavelet transform, energy entropy and singular value decomposition, using the difference of complexity degree of electric power system fault transient high frequency signal, the characteristic of wavelet singular entropy with internal and external fault is analyzed and the startup and trip criterion of non-unit transient protection based on wavelet singular entropy is constructed. The PSCAD/EMTDC simulation results show that this scheme is insensitive to fault type, fault location, fault resistance and fault inception angle. The protection algorithm is simple. Favorable adaptability and sensitivity can be realized.