500kV进口合成绝缘子芯棒脆断原因分析及对策

通过对一起合成绝缘子芯棒脆断事故的分析以及同批次运行的500 kv进口合成绝缘子的抽样试验,分析了合成绝缘子芯棒脆断的原因,发现该绝缘子芯棒脆断主要是由于端部密封不良及界面结构设计不合理,造成酸蚀并最终导致芯棒机械性能下降而发生脆断,同时,对该类运行中合成绝缘子的使用提出了相应的对策,以保证电网的安全可靠运行.     

合成绝缘子芯棒脆断与酸蚀的试验研究

合成绝缘子芯棒脆断与酸蚀的试验研究广东省电力试验研究所陆国庆，何宏明，瞿励，盘荣旋，张军，李志峰１芯棒脆断现象及机理合成绝缘子的机械损坏可分为常态损坏及脆断损坏两种。常态损坏是由于芯棒截面的应力分布不均使局部应力过大所引起的，它往往发生在固定端头的内...     

500kV合成绝缘子芯棒脆断的分析及对策

通过对一起合成绝缘子芯棒脆断事故的分析以及同批次运行的500kV进口合成绝缘子的抽样试验,分析了合成绝缘子芯棒脆断的原因,发现由于端部密封不良及界面结构设计不合理,造成酸蚀并最终导致芯棒机械性能下降而发生脆断,同时,对合成绝缘子的使用提出了相应的对策和建议.     

500kV罗北甲线合成绝缘子芯棒脆断原因分析

文章分析了合成绝缘子芯棒脆断的原因，芯棒脆断是由端部密封不良造成酸蚀引起的，脆断一般发生在合成绝缘子的高压端。为防止脆断事故的发生，厂家在选用良好耐酸蚀芯棒的同时，应改进端部密封结构和均压环的设计，以防止密封失效。运行单位应对运行中的合成绝缘子加强检测，以便及早发现有隐患的合成绝缘子。     

防护复合绝缘子芯棒脆断的方法

针对高压输电线路复合绝缘子发生的脆断事故,提出采用无硼耐酸芯棒以外的另一种有效防护复合绝缘子芯棒脆断的方法。在复合绝缘子芯棒表面涂覆一层鳞片涂料,涂层厚度达0.1mm以上时,可以形成有效的应力腐蚀防护层。应力腐蚀测试结果表明,原耐应力腐蚀性能很差的芯棒可改变为能达到应力腐蚀标准的芯棒,且远远超过标准要求。芯棒耐应力腐蚀性能可进一步随涂层厚度的增加而提高。该方法在不改变芯棒原来的电气、机械性能情况下,大大提高了芯棒的耐应力腐蚀性能,从而得到一种电气性能与耐应力腐蚀性能均优异的复合绝缘子芯棒;且该方法简单易行,可对现有耐应力腐蚀性能较差的芯棒进行改进。     

超声法检测绝缘子用玻璃钢芯棒脆断裂纹的研究

脆断是高电压复合绝缘子在很低的日常载荷下发生的恶性断裂事故，国内外研究认为应力腐蚀造成了绝缘子芯棒脆断的发生。文中根据芯棒脆断的特点，提出以超声纵波斜入射检测芯棒脆断横截面上的裂纹，同时据此研制了一种用于芯棒脆断裂纹检测的超声探头，并对芯棒脆断时裂纹的扩展过程进行了检测，得到了芯棒脆断裂纹发展过程中超声脉冲回波幅值的变化并对其进行了讨论分析，这对于进一步了解复合绝缘子的脆断机理有重要意义。     

复合绝缘子芯棒脆断原因分析及研究现状综述

本文详细介绍了复合绝缘子芯棒脆断原因及主要影响因素,在此基础上叙述了目前国内外为降低绝缘子脆断发生率采取的一些措施,并有针对性的介绍了对芯棒耐应力腐蚀性的改进。     

复合绝缘子芯棒脆断原因分析及研究现状综述

本文详细介绍了复合绝缘子芯棒脆断原因及主要影响因素,在此基础上叙述了目前国内外为降低绝缘子脆断发生率采取的一些措施,并有针对性的介绍了对芯棒耐应力腐蚀性的改进.     

光纤光栅监测复合绝缘子非耐酸芯棒脆断过程

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1.1λ_(wmax)和0.9λ_(wmin)(λ_(wmax)、λ_(wmin)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。     

500 kV葛双一回复合绝缘子芯棒裂断原因分析

通过对一起复合绝缘子芯棒断事故特征分析和同期运行在500kV输电线路上的复合绝缘子抽样试验,初步判断复合绝缘子芯棒断裂原因属酸蚀脆断,并据此提出防止类似事故发生的措施,即厂商应改进金具接头界面的密封工艺并注意复合绝缘子芯棒的抗蚀性能,而设计者应改进复合绝缘子的技术参数。     

FRP rods for brittle fracture resistant composite insulators

Brittle fracture of fibreglass reinforced polymer (FRP) rods can lead to mechanical failures of composite insulators even at low mechanical loads during operational service. Although this fact has been known for 20 years, it may still be a problem in some designs of composite insulators at the present time. In order to find countermeasures against brittle fracture, a study was carried out in the early eighties. It turned out that brittle fracture is a problem of FRP material and that material compositions exist, resistant to brittle fracture. A brittle fracture resistant FRP rod introduced in 1983 in one particular design of composite insulators resulted in a 15 year excellent service performance. This study deals with details of brittle fracture of FRP rods. Test setups were established to induce brittle fracture artificially. It was realized that brittle fracture is some kind of stress corrosion related to the composition of the FRP material. A broad variety of FRP materials was evaluated, showing the influence of the components of FRP material on the brittle fracture behavior of FRP rods as well as the effects of different manufacturing processes. The compositions of brittle fracture resistant FRP rods are disclosed. The results from artificial testing are compared with brittle fracture of FRP rods that occurred in composite insulators in operational service. Although no quantitative correlation could be established, the trend concerning the material behavior of FRP rods is similar     

复合绝缘子用耐酸芯棒的脆断性能研究

研究了复合绝缘子用耐酸芯棒的性能,对4种芯棒在不同浓度的硝酸中的耐腐蚀性能进行了长期试验.结果表明,各项指标都符合应力腐蚀试验标准的耐酸芯棒其耐腐蚀性能也存在较大差别,性能好的耐酸芯棒即使在非常严酷的条件下也很难发生脆断.为适应不同工程应用的要求,作者根据试验结果讨论了选择优良耐酸芯棒的试验方法.     

复合绝缘子运行过程中芯棒出现脆断原因初析

复合绝缘子在运行过程中，高压端的芯棒与金具联接部位抽出现的断裂，不是纯拉造成的，而是耐酸性的芯同场强下电晕产生的ＮＯ２与水反省一成的硝酸缓慢腐蚀后在承担正常载荷时造成的。章分析了其断裂原因和作用机理，并提出了预防措施。     

Failure analyses of nonceramic insulators. Part 1: Brittle fracture characteristics

Nonceramic insulators, also referred to as composite, polymer or polymeric insulators, are used in overhead transmission lines with line voltages in the range of 69 to 735 kV. Despite the many benefits that nonceramic insulators offer in comparison with their porcelain counterparts, they can fail mechanically in service by rod fracture. One of the mechanical failure modes of the insulators is a failure process called brittle fracture, which is caused by the stress corrosion cracking (SCC) of the GRP rods. The process is catastrophic and unpredictable, leading to the drop of energized transmission lines. The most important characteristics of the brittle fracture process, which can occasionally affect high voltage nonceramic transmission line insulators, leading to their catastrophic in-service failures, have been presented in this article. In addition, several experimental techniques were suggested for the simulation of brittle fracture under laboratory conditions. Only the most important aspects of brittle fracture process have been discussed here.     

Mechanism of brittle fracture in nonceramic insulators

The results of an investigation concerning a mechanism of brittle fracture in glass reinforced plastic (GRP) rods used in non-ceramic insulators (NCI) are presented. Commercial grade GRP rods and GRP rods from actual insulators were exposed to ultra-pure water (UPW) and acids while being subjected to mechanical stresses. The experimental results revealed that water has the potential of inducing stress corrosion cracking on the fibers and hence brittle fracture in the rods. It is observed that the fracture proceeded faster when the rods were exposed to UPW than when exposed to acids. Furthermore, a brittle fracture in an epoxy cross-arm, which was installed in a region where the formation of acids in the atmosphere can be neglected, is analyzed. Based on these evidences, it is postulated that the failure of in-service NCI in the brittle mode can occur under the influence of water and mechanical stresses, and that the failure is more likely to happen with water than with acids.     

复合绝缘子断串原因分析及防范措施

复合绝缘子断串问题是威胁输电线路安全稳定运行的关键问题。为系统分析复合绝缘子断串类型和原因,文中对实际运行复合绝缘子断串样品进行了统计分析,并对金具破损及芯棒脆断等引起的断串问题进行了总结归纳。结果表明绝缘子芯棒断串原因主要为端部密封失效、外护套破损、芯棒与护套界面粘结失效等。基于上述分析,文中提出了加强入网检测和运行性能分析、重视日常带电检测工作及对重要通道复合绝缘子技术改造三方面措施,从而为复合绝缘子断串防治提供参考。     

复合绝缘子使用现状及其在特高压输电线路中的应用前景

回顾了我国复合绝缘子的研制以及大规模应用的历史,对于国内复合绝缘子在使用中出现的一些主要问题,如芯棒脆断、机械性能、界面击穿、沿面闪络及老化性能等方面进行了统计、分析和总结,最后展望了复合绝缘子在特高压输电线路中的应用前景。