Classification and Location of Faultson Double Circuit Series Compensated Transmission Line using Wavlet Transform

Abstract

On prevailing power system network, double circuit transmission lines are used to enhance the consistency and power transfer capability. To improve the power quality of the transmission lines, compensation circuits are integrated. In order to increase the reliability of the system and reinstate the power supply in time, it is of immense important to classify and locate the fault rapidly and to isolate the faulty section precisely. In this dissertation, wavelet transform has been used for classification and location of various types of faults with different inception angles on double-circuit series compensated transmission line with different compensation levels in both the lines. Db4 and Haar wavelets are used to calculate the fundamental frequency components of voltage and current signals. Data from one end of the line is utilized for this method. Db4 is considered effective for fault classification and Haar wavelet for fault location. Low frequency components of the signal i.e. approximation coefficients of wavelet has been considered to classify and locate the fault so as to remove the effect of transients and harmonics. Average values of Level 6 approximation coefficients of currents are calculated by using db4 wavelet to classify the various types of faults. Flow chart for fault classification has been proposed. The line impedance from the sending end to the occurrence of the fault position has been considered for fault location. Impedance of distributed parameter transmission line before and after compensation has been calculated using rms values of voltages and currents of A6 coefficients of Haar wavelet and has been compared with the actual impedance of the faulty section. Fault location error has been tabulated for various types of faults with different distances, inception angles and different compensation levels on line1 and line2.