Travelling wave method for transmission system fault location

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

A Modified Artificial Bee Colony for Probabilistic Peak Shaving Technique in Generators Operation Planning: Optimal Cost–Benefit Analysis

In the generation of operating system planning, saving utility cost (SUC) is customarily implemented to attain the forecasted optimal economic benefits in a generating system associated with renewable energy integration. In this paper, an improved approach for the probabilistic peak-shaving technique (PPS) based on computational intelligence is proposed to increase the SUC value. Contrary to the dispatch processing of the PPS technique, which mainly relies on the dispatching of each limited energy unit in sequential order, a modified artificial bee colony with a new searching mechanism (MABC-NSM) is proposed. The SUC is originated from the summation of the Saving Energy Cost and Saving Expected Cycling Cost of the generating system. In addition, further investigation for obtaining the optimal value of the SUC is performed between the SUC determined directly and indirectly estimated by referring to the energy reduction of thermal units (ERTU). Comparisons were made using MABC-NSM and a standard artificial bee colony and verified on the modified IEEE RTS-79 with different peak load demands. A compendium of the results has shown that the proposed method is constituted with robustness to determine the global optimal values of the SUC either obtained directly or by referring to the ERTU. Furthermore, SUC increments of 7.26% and 5% are achieved for 2850 and 3000 MW, respectively

A systematic approach for evaluating the accuracy of overhead line fault location using the traveling wave method

In the power system, the high-voltage transmission lines are responsible for transmitting large amounts of energy from one location to another. However, this feature is not always possible because of different defects that may occur on these lines. Therefore, power suppliers must provide exact defective locations where maintenance lines can accelerate, system reliability improved, and unnecessary operating expenses eliminated. In this paper, the traveling wave technique based on wavelet transform proposes to find the exact location assist with voltages and currents signal at the single and multi-end of the transmission line. The techniques simulated using PSCAD / EMTDC software based on a single-phase to ground fault and tested on the sample system. A compendium of the results has shown that the multi-end technique is more accurate than the single-end technique