一例主变侧离相母线软连接温度高原因分析及处理

Analysis and Treatment of a Case of High Temperature of Isolated Phase Bus in Main Transformer Side

国家能源集团国电蚌埠发电有限公司一期主变,其低压侧与离相母线的软连接在投运十年后发现有温度逐渐升高的现象,该缺陷严重影响了正常的机组出力,查清温度升高原因并采取针对改善措施,为避免其他变压器产生类似缺陷提供借鉴,文章给出了软连接温度升高缺陷的原因分析、针对性改善措施的详细经过.根据软连接发热部位的痕迹,对软连接与母线、套管搭接面的镀银层厚度检测、装配尺寸、变压器升高座法兰发热等方面进行分析,结合红外检测后查明,由于在设备设计时,未综合考虑母线外壳的感应电流影响,组装阶段及后期检修工艺把控不严,软连接的接触电阻变大发热与升高座法兰感应电流发热的叠加,导致变压器低压侧与离相母线的软连接温度升高.针对主变、离相母线连接处的电磁感应的影响,设备运维单位在设备检修中采取相应的改进措施.

Pick In order to avoid similar defects in other transformers,the soft connection between LV side and isolated phase bus of phase I main transformer of state energy group Guodian Bengbu Power Generation Co.,Ltd.was found to have gradually increased temperature after ten years of operation,which seriously affected the normal unit output,found out the causes of temperature rise and took corresponding improvement measures,so as to provide reference for avoiding similar defects in other transformers Cause analysis of temperature rise defects and detailed process of targeted improvement measures.According to the trace of the heating part of the soft connection,this paper analyzes the thickness detection of the silver plating layer on the overlapping surface of the soft connection and the bus and the sleeve,the assembly size,the heating of the fl ange of the rising base of the transformer and so on.After the infrared detection,it is found out that the infl uence of the induced current of the outer shell of the bus is not considered comprehensively in the design of the equipment,the control of the assembly stage and later maintenance process is not strict,and the contact of the soft connection is not strict The temperature of the soft connection between the low voltage side of the transformer and the isolated phase bus increases due to the superposition of the heating of the resistance and the induced current of the raised base fl ange.In view of the infl uence of electromagnetic induction at the connection of main transformer and isolated phase bus,the equipment operation and maintenance unit shall take corresponding improvement measures in equipment maintenance.