光纤光栅监测复合绝缘子非耐酸芯棒脆断过程  

Application of FBGs to Brittle Fracture Monitoring of Rods in Composite Insulators

作　　者：郝艳捧[1] 曹航宇 韦杰 张智敏 潘锐健 黄磊 HAO Yanpeng;CAO Hangyu;WEI Jie;ZHANG Zhimin;PAN Ruijian;HUANG Lei(School of Electric Power,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学电力学院,广州510640

出　　处：《高电压技术》2021年第6期1998-2006,共9页High Voltage Engineering

基　　金：国家自然科学基金委员会-国家电网公司智能电网联合基金重点项目(U1766220)。

摘　　要：复合绝缘子脆断是恶性事故,为此研究复合绝缘子脆断监测技术,在10 kV复合绝缘子非耐酸芯棒表面粘贴4根光纤,其中1根级联2个温度光栅,另外3根各级联5个应力光栅,进行温度标定试验、拉力标定试验和应力腐蚀试验。结果表明,非耐酸芯棒应力腐蚀试验中出现了3个裂纹,其中1个裂纹为脆断断口,其余2个裂纹未脆断。表面多个光栅实现了非耐酸芯棒完整脆断过程的温度与应力监测,发现芯棒应力腐蚀分为4个阶段,阶段1初期无变化,阶段2腐蚀放热,阶段3裂纹起裂,阶段4裂纹快速发展至断裂。从阶段2开始腐蚀区放热,最高高于环境温度2.46℃,温差1℃可以作为复合绝缘子脆断过程中腐蚀放热阶段的早期预警阈值。应力光栅对裂纹的轴向检测距离约20 mm,其波长偏移量1.1λwmax和0.9λwmin(λwmax、λwmin分别为稳定范围的最大值和最小值)可以分别作为裂纹起裂阶段、裂纹严重阶段的早期预警阈值来监测复合绝缘子脆断。该光纤光栅技术为芯棒脆断/朽断机理、防脆断/朽断芯棒材料和复合绝缘子脆断监测提供了技术研究手段。The brittle fracture of composite insulators is a malignant fracture accident.Therefore, we investigated the brittle fracture monitoring of composite insulators. Four optical fibers were pasted on the surface of the fiber-reinforced plastic(FRP) rod of a 10 kV composite insulator, one of which has 2 fiber Bragg gratings(FBGs) to measure temperatures, and the others have 5 FBGs to measure stresses. Temperature calibration tests, tension calibration tests, and stress corrosion tests were carried out on the rod with surface-encapsulated FBGs. The results showed that three cracks appeared in the stress corrosion tests of the rod, of which crack 1 developed into a brittle fracture, and the other two did not. The temperatures and the stresses in the entire brittle fracture process of the rod were monitored by the FBGs on the rod surface. It is found that the stress corrosion process can be divided into four stages as follows:no change in the initial stage, corrosive heat release in the second stage, crack initiation in the third stage, and finally, the cracks developing rapidly until the rod break. From the second stage, the heat begins to emit in the corrosion zone, and the maximum difference between the corrosion zone temperature and the ambient temperature reaches 2.46 ℃, thus a temperature difference of 1 ℃ can be used as an early warning for the second stage in the brittle fractures of composite rods. The stress FBGs can detect a crack with an axial distance of 20 mm between them, and a wavelength shift 1.1λwmax or 0.9λwmin of the stress FBGs can be used as an early warning for a crack initiation or a serious crack in the brittle fracture process of composite insulators, respectively. By the FBGs monitoring method in this paper, a technical means can be provided to investigate fracture mechanisms and materials against brittle fracture/decay-like fracture of composite insulators.

关 键 词：光纤布拉格光栅 非耐酸芯棒 脆断 在线监测 应力腐蚀试验 

分 类 号：TM216[一般工业技术—材料科学与工程]