Partial Discharge Characteristic Analysis of Distribution Network Overhead Line Based on Remote Detection

With the reliability of distribution network being received more and more awareness, the research in equipment surveillance for distribution network gains much more attention. One of the critical preconditions for this research is to analysis the details of faults or defects, such as fault cause and discharge characteristics. According to our investigations, we found that the insulation layer of some overhead lines is frequently burned by the electric arc while the cause of arc is still unknow. This significantly reduces the reliability of distribution network. This paper focuses on the development process of this ablation and related discharge characteristics. In order to find the cause, we built a simulated distribution line model with insulator, binding wire and overhead line in our laboratory. By changing the status of equipment, we observed and recorded the performances of different conditions. During our tests, partial discharge measurement, infrared thermal imaging, ultrasonic detection, ultraviolet imaging and UHF detection were applied to measure the status of the system and discharge characteristics. When the corona occurs, there was no obvious temperature rising observed in discharge area with infrared thermal imaging method. This explains why operation and maintenance team cannot locate this fault in its early stages. Conversely, we were able to obtain significant signals with other four methods, and confirmed the measured signals are different with different causes. Therefore, the discharge characteristics can be described by analyzing UHF signal, ultrasonic signal and ultraviolet imaging. It is also possible to evaluate equipment status by analyzing the measured signals and characteristics.