Researches on abnormal operating and Condition Assessment Methods for insulating tubular bus-bar

In recent years, insulating tubular bus-bar has been widely used in power systems for its excellent electrical performance. However, as some new electrical equipment, there is still no unified principle at home and abroad, and little research is done on its operating characteristics. This leads to a confused market, and some abnormal operating phenomena appear in operation. In this paper, a 35kV insulating tubular bus-bar which operates abnormally in a substation is studied. According to the disintegration phenomena, experiment and simulation results, we have a suspicion that the abnormal phenomena is caused by the unreasonable match between semi-conducting layer and metal shielding layer. As the semi-conducting layer is weak in electric strength and inflammable, this defect develops quickly into bulging, smoking and burning when partial discharge appears. Besides, some methods to evaluate tubular bus-bar after the handover tests is proposed, and online detections, such as infrared temperature measurement, high frequency partial discharge, are recommended in daily inspection and maintenance.