一起极Ⅰ低端400千伏穿墙套管阀厅侧金具异常发热的分析及处理

Analysis and Treatment of Abnormal Heating of Ⅰ Low-end 400kV Througe Wall Casing Valve Hall Side Fittings

本文分析了一起极Ⅰ低端400千伏穿墙套管阀厅侧金具异常发热事件。现场检查发现阀厅侧发热套管端子与本体法兰面紧固螺栓松动,接触面有明显发热痕迹,同时检查直流场侧套管端子也存在螺栓力矩不足情况。结合现场检查情况综合分析,套管端子紧固螺栓松动导致端子与法兰面接触电阻增大,是造成套管端子发热的直接因素,安装在套管端子上的六分裂金具中有两处软连接相互接触,当套管端子发热引起铜制软连接端板受热膨胀,之前接触的端板反向推动铜抱箍,使铜抱箍对套管端子的抱紧力减小,端板热胀冷缩的过程在一定程度上影响接头不规律发热。该事件提醒我们需重视电力设备的质量问题,对套管厂内组装工艺要把好关,做好出厂验收环节的验收工作,安装方法需要结合现场实际情况做到最优化安装,并且验收环节应做到严谨、细致,避免此类事件发生。针对该异常事件,本文给出具体的处理措施,供大家参考。

In this paper, a low-end 400 kV through-wall casing valve hall side fittings abnormal heating event has been analyzed.The on-site inspection found that the fastening bolts of the heating bushing terminal on the valve hall side and the flange surface of the body were loose, and there were obvious signs of heating on the contact surface.At the same time, the bushing terminal on the DC field side was also checked for insufficient bolt torque.Combined with the comprehensive analysis of the on-site inspection, the loosening of the casing terminal’s tightening bolts leads to an increase in the contact resistance between the terminal and the flange surface, which is a direct factor causing the casing terminal to heat up.There are two soft spots in the six-split fittings installed on the casing terminal.The connections are in contact with each other.When the bushing terminal heats up, the copper flexible connection end plate is thermally expanded, and the previously contacted end plate pushes the copper hoop in the opposite direction, so that the holding force of the copper hoop to the casing terminal is reduced, and the end plate thermally expands The process of cold shrinkage affects the irregular heating of the joint to a certain extent.The incident reminded us that we need to pay attention to the quality of power equipment, and control the assembly process in the bushing factory well, Strictly carry out the acceptance of factory acceptance.The on-site installation method needs to be optimized according to the actual situation on the site, and the acceptance process should be rigorous and meticulous to avoid such incidents.The specific measures for handling the event are given for your reference.