摘要
针对一起500 kV同塔双回线路多支复合绝缘子发热事件,开展了现场不同角度的无人机红外测试,对酥朽缺陷绝缘子的温差、发热区段数量及长度进行了分析,并对更换后的发热绝缘子开展外观检查、红外复测、剖检及工业CT、带护套水扩散试验,对比了实验室与现场红外测试差异,通过剖检对比了芯棒酥朽区段与发热位置的关系,并对酥朽原因进行了讨论。结果表明,现场38支酥朽复合绝缘子,94%的绝缘子为1处或2处芯棒发热、6%出现3处发热,79%的绝缘子发热区段长度最长为1至2个伞裙单元、21%存在3-5个伞裙单元的连续发热;除1支绝缘子外,其余缺陷绝缘子温度最高点不处于芯棒高压端。不论高压端是否发热,剖检发现绝缘子高压端位置均存在酥朽,酥朽位置从高压端延伸的最远距离,与红外图像获得的发热位置距离高压端最远距离接近,上述结果可以作为现场发热原因及严重程度判断的依据。不同方向测得的发热区域位置接近、发热区段长度接近,但是温差结果往往相差较大,一侧温差测试结果可达另一侧结果的3.2倍。实验室测得的发热区段长度比现场红外测试结果更长,1~2 K的发热区域获取更为完全,因此现场有必要开展多个角度的近距离红外测试并尽量避免光照的影响,以确保缺陷等级判定的准确。缺陷绝缘子护套存在孔洞缺陷、芯棒局部存在裂纹缺陷,同时绝缘子均压环罩入深度不足,上述因素综合作用是引发本次芯棒酥朽的原因。
In response to a heating incident involving multiple composite insulators on a 500 kV double circuit line on the same tower,on-site infrared testing of unmanned aerial vehicles was conducted from different angles.The temperature difference,number and length of heating sections of insulators with britle defects was analyzed.Visual inspection,infrared retesting,dissection,industrial CT,and water diffusion test with protective sheath were conducted in laboratory with the replaced heating insulator.The differences between laboratory and on-site infrared testing were compared,and the relationship between the core rod decay section and the heating position was compared through dissection.The reasons for cracking were discussed.It is indicated that among the 38 decay composite insulators,94%of the insulators is with one or two heating sections,6%experienced heating at three locations,79%of the insulators had heating sections with the longest length ranging from 1 to 2 umbrella skirt units,and 21%had continuous heating with 3-5 umbrella skirt units.Except for one insulator,the highest temperature point of the other defective insulators is not at the high voltage end of the core rod.Regardless of whether the high voltage end is heated or not,the dissection found that the decay section was from the high voltage end position of the insulator.The farthest distance of the decay section boundary from the high voltage end,is close to the the farthest distance of heating section boundary from the high voltage end.The positions of the heating areas and the lengths of the heating sections measured in different directions are close,but the temperature difference results often differ greatly.The maximum temperature difference test result on one side can be 3.2 times that on the other side.The length of the heating section measured in the laboratory is longer than that of the field infrared test results,and the acquisition of the 1~2 K heating area is more complete.Therefore,it is necessary to conduct close range field infrared testi
作者
李特
张永
柳骏
戚宣威
陶瑞祥
郑宏晔
LI Te;ZHANG Yong;LIU Jun;QI Xuanwei;TAO Ruixiang;ZHENG Hongye(State Grid Zhejiang Electric Power Research Institute,Hangzhou 310014,China;State Grid Zhejiang Electric Power Limited Company,Hangzhou 310004,China;State Grid Taizhou Electric Power Supply Company,Taizhou 315000,China)
出处
《电瓷避雷器》
CAS
2024年第5期145-154,共10页
Insulators and Surge Arresters
基金
国网浙江省电力有限公司科技项目“复合绝缘子酥朽断裂劣化特性及检修策略研究”(编号:5211TZ240001)。
关键词
复合绝缘子
酥朽
发热特征
红外
起始原因
composite insulator
decay
heating character
infrared
initial cause
