Discrete wavelet transform and Fuzzy Logic algorithm for identification of fault types on transmission line

This paper proposes a new technique using discrete wavelet transform (DWT) and Fuzzy Logic in order to identify the fault types on single circuit transmission lines. The mother wavelet daubechies4 (db4) is employed to decompose, high frequency component from these signals. Positive sequence current signals are used in fault detection decision algorithm. The variations of first scale high frequency component that detect fault are used as an input for the fuzzy logic. Fuzzy logic is also compared with the Back-propagation (BP) neural network in this paper. The proposed method gives a satisfactory accuracy, and will be very useful in the development of a modern protection scheme for electrical power transmission systems.