Travelling wave method for transmission system fault location

Abstract

Extra high voltage transmission lines are designed to transfer large amount of power from one location to another. The length exposed to the environment is a major reason for occurrence of faults on the lines. A fault on a high voltage transmission line affects the stability of the overall power system, which sometimes leads to permanent damage of the equipment. Travelling wave theory on transmission line systems based on faults and others parameter is presented. Voltage and current travelling waves are generated when a fault occurs on the transmission line. The velocity of propagation of travelling waves is finite and the level of the waves decreases with increase in the distance traveled. Information about the fault can be obtained by analyzing the travelling waves. A few travelling wave techniques, which are based on analog signal processing, to locate the location in transmission lines, are proposed in this thesis. The travelling waves are extracted from the modal voltages and currents at the single and multi terminals of the transmission line. The techniques identify and locate the fault by using the information contained in the waves. A power system has been modeled in the results of single phase to ground fault. From the wave, arrival and reflection times are obtained and then used in different formulas for both single and multi end to determine the fault locations. The techniques have been simulated using PSCAD/EMTDC and their performance has been tested on 2 Busbars and IEEE 15 Busbars test systems. The results reveal that the technique is able to locate the fault. Multi end approach result is found to be more accurate than single end technique.