Fault classification and location in Three Phase Transmission Lines using Discrete Wavelet Transform

Faults in transmission lines have several adverse impacts on the overall health of the power system. Circuit breakers and relays help in isolating the fault and protecting the entire system. Prompt tripping of the circuit breakers is a vital aspect of power system protection, to minimize the extent of damage. This paper presents an efficient algorithm to detect faults, classify the fault type and locate the fault in transmission lines using Discrete Wavelet Transform (DWT) and Travelling Wave Theory (TWT). A two bus system is taken for study and different types of faults are created in the transmission line. Then DWT is applied on faulty current signals to extract detailed coefficients at higher level of decomposition, which in turn are used to classify the fault. For locating the fault, detailed coefficients at first level of decomposition and TWT are used. Results obtained depict the accuracy of the proposed algorithm in classifying and locating the faults in transmission line. Same algorithm is implemented in hardware for LG fault in all the three phases and the results are presented.