碳纤维复合芯导线耐张线夹断裂分析

Analysis on the Strain Clamp Fracture of ACCC

对某220 k V输电线路碳纤维复合芯导线的失效耐张线夹进行结构检测,发现铝管压接标示线定位错误造成压接后局部应力集中,线夹装配不符合规范要求。通过开展耐张线夹楔型夹握力、铝管握力和引流板温升试验,分析了线夹装配、温升对其握力的影响,指出引流板装配不良在大电流下发热使得楔型夹握力下降,铝管升温、承载并断裂致使碳纤维复合芯棒从楔型夹中脱落。提出碳纤维复合芯导线耐张线夹安装和安全运行的技术要求。

A structure testing was conducted on the disabled ACCC strain clamp of a 220 kV transmission line. It was found that the line for hydraulic crimping on the aluminum tube was wrongly positioned after crimping, which resulted in local stress concentration, and the assembly quality of strain clamp was not in conformity with the requirements of the specification. A series tests are conducted, including the holding force test of wedge clamp and aluminum tube, the temperature-rise test of drainage board, and the influences of the clamp assembly and the temperature rise on holding force are discussed. It is concluded that the poor installed drainage board with heavy current generates an enormous amount of heat, which decreases the holding force of clamp, and leads to the temperature rise of aluminum tube. As a result, the aluminum tube may break with loading and the carbon fiber composite core rod may fall off from the wedge clamp. The technical requirements for the installation and safe operation of strain clamp are presented.