Method for determining the locations of power cable damage

Abstract

Problem. Existing methods for remotely detecting cable damage locations, except in the case of cable breakage, have a common drawback. They are unable to accurately separate the cable core resistance from the transient resistance at the short-circuit location, leading to low accuracy in fault detection. The posterior transient resistance at the short-circuit location can vary widely, depending on when the repair crew arrives. Goal. The goal of this study is to propose a method for identifying the location of "floating breakdown" cable damage. Methodology. The method involves using short-circuit indicators to determine the type and area(s) of the short circuit. The UNI-TUT255A device, a current clamp type, is then installed on the damaged cable core. The Imax option with memory is set, and the cable is switched on at the rated voltage. By comparing the recorded shock current value with the values obtained from a short-circuit model of the cable in MATLAB, the location of the damage along the length of the cable is determined. The point where the shock current value of the model matches the recorded value corresponds to the location of the short circuit. Originality. The proposed method addresses the challenge of locating faults in power cables, specifically those of the "floating breakdown" type. This type of cable damage, which occurs when the cable is accidentally disconnected during a short circuit, poses difficulties in detection, as traditional methods may show normal readings. The method presented in this study overcomes these limitations and provides a practical solution for identifying "floating breakdown" faults. Practical value. The results obtained from this method allow for the accurate detection of faults at the nominal voltage, without the need for burning the cable. This reduces the probability of additional damage caused by overvoltage. Furthermore, the method requires only one operator to carry the necessary equipment, eliminating the need for transport with powerful burning installations typically used in traditional methods.