一起500kV导线线夹过热缺陷案例分析OA

As an important part of the wire connection,the clamp is widely used in the overhead lines of the power system.Due to the broken strand of the wire and the loose contact of the bolt,the overheating of the clamp occurs from time to time.In this paper,an emergency defect case of abnormal heating of the down-lead clamp above the high voltage side disconnector of 500kV main transformer in substation is analyzed.The DC resistance test,high current temperature rise test,slip test,single line tensile force test and disassembly inspection are carried out.The reason of overheating is that the fastening torque of the fixed bolt does not meet the standard when it is put into operation,and the number of gaskets is not uniform.During the long-term operation,the wire force causes the clamp bolt to loosen,which makes the end of the clamp more prone to wet corrosion and further aggravates the poor contact,resulting in an increase in contact resistance,and the slip test and the tensile force test do not meet the requirements.At last,a targeted operation and maintenance strategy for strengthening infrared monitoring of this batch of wire is proposed.