带电清洗剂对绝缘子用硅橡胶的溶胀效应及其影响研究

复合支柱绝缘绝缘子由于具有优异的防污性能,在直流换流站得到了广泛应用,但其在空间电荷和静电效应下积污严重而存在大面积污闪风险。为了评估复合支柱绝缘子带电绝缘清洗的可行性,对硅橡胶在新型绝缘清洗下的溶胀特性及其对硅橡胶的电气性能、力学性能以及憎水性的影响开展了试验分析。研究结果表明:硅橡胶溶胀随着溶胀时间的增加溶胀指数和直径增长率持续增大,浸泡时间20 min时圆形硅橡胶试样的直径增长率为4.7%、溶胀指数为6.8%。硅橡胶的复介电常数、复电容、介质损耗因素随着频率、溶胀指数增大而减小;在10-2~103Hz频域范围内硅橡胶溶胀不会造成介电性能下降。硅橡胶溶胀对憎水性和憎水迁移性无明显影响,干燥洁净硅橡胶溶胀前后接触角θ平均值在92°~98°范围内浮动,人工积污并经过憎水迁移后θ平均值在119°~128°范围内浮动。硅橡胶在发生溶胀后其力学性能小幅度下降,溶胀20 min的其断裂拉伸强度下降2%。试验结果表明硅橡胶在清洗剂中溶胀度受浸润时间影响较大,溶胀效应对憎水性、电气和力学性能影响较小,可通过采用易挥发配方或强对流措施控制清洗剂残留对硅橡胶的影响。     

高聚物复合绝缘子紫外老化性能研究

传统高温硫化（HTV）硅橡胶复合绝缘子以其优异的憎水性和憎水迁移性,广泛应用于国内外输电线路上。但随着特高压工程的开展,越来越多的输电线路需要跨越强紫外辐射、强风沙以及鸟啄频发地区,而在这类气候恶劣地区极易造成传统HTV硅橡胶绝缘子外绝缘性能的下降以及材料的损伤。针对这一情况,采用耐紫外线、耐气候性能强,机械性能稳定的高聚物复合绝缘子与传统HTV硅橡胶绝缘子在紫外老化性能方面进行对比,旨在研究高聚物复合绝缘子在西北高原强紫外辐射地区的老化特性。研究结果表明：在短波紫外光（UVC）持续照射下,环氧材料的拉伸强度和硬度均远高于硅橡胶,具有更好的韧性,已达到防鸟啄和耐踩踏的目的,但憎水性相比较于硅橡胶材料仍略有不及,但仍满足户外运行要求。     

Breakdown strength at the interface between epoxy resin and silicone rubber-a basic study for the development of all solid insulation

As a key component for a future power substation system entirely consisting of solid insulating materials, a special connection system between different pieces of power equipment has to be developed. A soft dielectric such as silicone rubber and a hard one such as epoxy resin are to be used for this connection. This paper describes the interfacial breakdown strength between silicone rubber and epoxy resin using two types of model samples on which the electric field can be applied in parallel or perpendicularly to their interface. Partial discharge characteristics at the interface and the effect of air penetration on the breakdown voltage along the interface are discussed.     

含缺陷复合绝缘子的加速老化试验

对芯棒与护套交界面上含不同种类缺陷的复合绝缘子进行人工加速老化试验,缺陷包括人为内置的木片、铜片、部分区域脱粘等.对绝缘子样品施加逐步升高的交流电压,记录泄露电流与表面电流.同时在干燥与雾室环境下进行试验,研究缺陷类型、缺陷大小以及水分侵入对复合绝缘子老化过程的影响.加压过程中,当泄露电流超过2mA时,水煮后的含缺陷绝缘子样品的温度将会明显升高,其中缺陷端部位置的温度最高,并且护套出现蚀损孔.当护套出现蚀损孔后,芯棒将直接暴露在外部环境中,这将加速复合绝缘子的老化过程,影响复合绝缘子的长期安全运行.     

On the breakdown strength of silicone rubber

Polymeric materials are an alternative to porcelain and glass regarding outdoor HV insulators. Silicone rubber appears to be one of the main candidates to replace porcelain and glass. Although much work has already been done regarding the behavior of complete polymeric insulators in the laboratory and in the field, relatively little is known with respect to the breakdown strength of silicone rubber. In this paper the breakdown strength of silicone rubber with respect to gap spacing and the electrical behavior of built-in interfaces inside the silicone rubber are investigated     

混合编程法及其在绝缘子电场和电位分析中的应用

室温硫化硅橡胶防污闪涂料在电力系统外绝缘中有着广泛的应用,有必要分析它对电场和电位分布的影响。分析不同厚度情况下硅橡胶涂层的电阻率和相对介电常数对绝缘子附近最大强场、沿面电场和电位的影响。采用Matlab与ANSYS混合编程的方法实现了绝缘子的自动建模,采用C++Builder(BCB)与ANSYS混合编程的方法实现了自动导出lis文件,节省了工作量和后续处理时间,同时使用Matlab对lis文件处理获得沿面的场强和电位。研究结果表明:瓷支柱绝缘子喷涂硅橡胶后无论是最大场强还是局部细节场强均未见明显变化;随涂层厚度、相对介电常数增加最大场强略有减少,但变化程度非常小,沿面平均场强略有增加;随电阻率的变化最大场强和沿面平均场强基本不变。电阻率、介电常数和厚度正常的取值范围内时硅橡胶涂层对绝缘子及附近电场畸变造成的影响可以忽略。     

Aging of polymeric and composite insulating materials. Aspects of interfacial performance in aging

Aging of polymeric and composite materials is reviewed mainly from the standpoint of their interfacial performance. Insulating materials can be divided into simple polymers and composites. Polymers for power cables, transformers, insulators and rotating machines consist of thermoplastics such as PE, PET and PPS, elastomers such as silicone, EPR and EPDM, and thermosets such as epoxy. Composites for GIS, rotating machines and insulators comprise epoxy/glass, epoxy/silica/alumina, and epoxy/mica systems. Aging processes are complicated in general, and take place under simultaneous multiple stresses such as electrical, thermal, mechanical and environmental stresses. Some of the phenomena covered in this paper are associated with the degradation by tracking and erosion and the loss of hydrophobicity in case of surface properties, and with PD, electrical treeing, water treeing and combined phenomena. The quality of cable insulation such as XLPE has been improved extensively from the standpoint of design electric strength. Interfacial problems will emerge for modification of cable joints. It is expected that polymers for outdoor use and filled epoxy resin systems should be improved from their environmental stability and from their design stress enhancement, respectively.     

Understanding the strength of epoxy-polyimide interfaces for flip-chip packages

Polyimides are commonly used as organic passivation layers for microelectronic devices due to their unique combination of low dielectric constant, high thermal stability, and excellent mechanical properties. Polyimides are well known to have poor adhesion to epoxy resins. Many surface treatment methods have been developed to increase epoxy-polyimide adhesion. These include various ion beam, plasma treatment, or chemical treatment methods. The goal of this research is to understand the strength of epoxy-polyimide interfaces by studying the effect of polyimide chemical structure on epoxy-polyimide adhesion. The four polyimides chosen in this study are commonly used in the microelectronics industry: poly (pyromellitic dianhydride-oxydianiline [PMDA-ODA], poly (3,3/spl acute/,4,4/spl acute/-biphenyltetracarboxylic dianhydride-phenylene diamine [BPDA-PDA], poly (hexafluoroisopropylidene-diphthalic anhydride-oxydianiline) [6FDA-ODA], and 5(6) -Amino-1-(4-aminophenyl)-1,3,3, trimethylindanbenzophenonetetacarboxylic dianhydride copolymer [BTDA-DAPI]. The adhesive strengths between an epoxy resin and these four polyimides were characterized using interfacial fracture mechanics and the critical interfacial strain energy release rates ranged from 20 to 179 J/m/sup 2/ depending on the particular polyimide used. The loci of failure for these epoxy-polyimide interfaces were analyzed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR), and found to be at the interphase region for all four interfaces. It is interesting that the strength of the interfaces appears to be related to the predicted interfacial widths from solubility parameter theory.     

复合绝缘子硅橡胶材料老化性能分析

分析了青海电网部分长时间服役的复合绝缘子硅橡胶材料的老化现象,研究了绝缘子用硅橡胶材料在高原地区的应用状况及其老化规律,采用核磁共振方法对硅橡胶材料进行了检测.结果表明,该检测方法是可行的,可快速、准确地监测电网运行中复合绝缘子的老化程度.     

Flashover mechanism of silicone rubber insulators used for outdoorinsulation-I

Experimental results show that the contamination performance of silicone rubber composite insulators is better than porcelain insulators. This is attributed to the hydrophobicity of the silicone rubber. This suggests that the flashover mechanism of these insulators is different. This paper experimentally investigates contamination build-up, diffusion of low molecular weight (LMW) polymer chains, surface wetting, electrical field caused interaction between droplets, generation of conductive regions and filaments, field intensification caused spot discharge and the ultimate flashover of silicone rubber along wetted filaments. The studies resulted in a new flashover mechanism, which provides a better understanding of the superior performance of silicone rubber outdoor insulators. The results will be useful for the development of improved laboratory test procedures and to evaluate composite insulators' performance in contaminated conditions. The part of the paper describes an overview of the flashover mechanism and the diffusion of LMW polymer chains and wetting of the silicone rubber surface in detail     

复合绝缘子内部缺陷的超声相控阵检测研究

为消除复合绝缘子内部缺陷对电网运行安全造成的隐患,针对小管径复合绝缘子缺陷检测,提出了一种基于超声相控阵的柔性水囊耦合检测方法。该方法采用硅橡胶薄膜与耦合装置实现了良好超声耦合,分别对平面硅橡胶、复合绝缘子护套与芯棒进行了检测实验。实验结果表明,对平面硅橡胶线性扫描优于扇形扫描,能够检测到0.8 mm的微小缺陷,为复合绝缘子伞群超声缺陷检测提供了新方法。对复合绝缘子护套和芯棒,扇形扫描优于线性扫描,护套最小可检测缺陷尺寸达到0.8 mm,芯棒达到1 mm,为复合绝缘子的在线检测提供了可能。     

Properties of interfaces in silicone rubber

A salt fog test and an inclined plane test have been combined in order to trace changes in electrical and mechanical properties as well as in chemical stability of high temperature cured silicone rubber (HTV) samples containing interfaces. The interfaces were created in two different ways. The first technique, named adding/curing, was based on pressing together an uncured HTV silicone plate towards a piece of already cured one, followed by curing at atmospheric pressure and high temperature. The second type of interface was made by joining two pieces of cured HTV rubber by silicone glue (RTV-1). Thereafter both types of samples were divided in two parts, one of which was additionally exposed to UV-radiation before testing. The combined salt fog inclined plane test did not reveal significant differences in the development of leakage currents, in the change of surface roughness, or in the degree of surface oxidation in comparison to reference samples of cured HTV rubber without interfaces. At the same time the leakage currents became lower on the UV-exposed samples. It is suggested that the reduction in leakage currents resulted from a combination of increased surface roughness and increased hydrophobicity. Reduction of mechanical properties of UV-exposed samples was also observed. The tensile testing showed that samples containing the adding/curing interfaces maintained their mechanical strength after ageing while the strength of the glued samples was significantly reduced, indicating that the adding/curing system has better long-term mechanical stability compared to the glued system     

复合绝缘子伞套老化状态模糊综合评估

针对硅橡胶复合绝缘子长期在户外运行时出现的老化问题,提出一种基于模糊综合评价的绝缘子状态评估方法.从硅橡胶复合绝缘子伞套材料角度出发,建立机械性能指标、憎水性指标、电气性能指标等4个一级指标,以及所属的12个二级指标.通过构建评价指标的隶属度函数来获得各指标的隶属度,结合改进层次分析法和熵权法的组合赋权法,对各指标进行...     

Flashover mechanism of silicone rubber insulators used for outdoorinsulation-II

Flashover mechanisms of silicone rubber used for outdoor insulation is presented and experimentally proven. A hydrophobic surface of silicone rubber wets and accumulates contaminants differently compared to conventional porcelain and glass insulators. This suggests that the flashover mechanism of silicone rubber insulators is different than porcelain and glass. This part of the paper experimentally investigates ohmic heating, electrical field caused interaction between water droplets, generation of conductive regions and filaments, field intensification caused spot discharges and the ultimate flashover of silicone rubber along wetted filaments. These studies have resulted in a new flashover mechanism which provides a better understanding of silicone rubber outdoor insulators and their excellent contamination performance. These results will be used for the development of a better laboratory test procedure to evaluate composite insulators' performance in contaminated conditions     

基于太赫兹波的复合绝缘子界面检测研究

复合绝缘子的交界面缺陷问题严重威胁着电网的安全运行。为了有效评估复合绝缘子的界面性能,研究基于太赫兹波的无损检测方法。首先理论分析了太赫兹反射波在不同性能界面中的传播过程。测试界面气隙、蚀损缺陷情形的太赫兹反射波,分析太赫兹波在含缺陷界面中的反射传播特性。针对气隙缺陷,提出通过太赫兹波形特征比对的定量检测方法;针对蚀损缺陷,提出基于波形差值的成像检测方法。根据太赫兹波形特征信息,可对界面气隙和蚀损缺陷进行分类诊断。对实际缺陷的测试表明,太赫兹时域反射波在复合绝缘子界面缺陷检测中具有较高的应用价值。     

青藏工程直流复合绝缘子用硅橡胶耐紫外老化研究

青藏交直流联网工程位于高海拔、强紫外线的青藏高原地区,恶劣的自然环境对复合绝缘子有着更高的技术要求.针对该地区紫外辐射强度高的特点,从配方优化角度对复合绝缘子用硅橡胶进行了改进,并对改进前后的硅橡胶材料进行了2000 h紫外老化对比实验.结果表明配方优化后的硅橡胶材料在拉伸强度、拉断伸长率、体积电阻率和憎水性等机械电气性能方面均有显著提高,能够满足青藏工程的使用要求.同时根据实验结果分析了硅橡胶材料的紫外老化机理和老化时间趋势,发现紫外线是通过切断硅橡胶的侧链并发生交联反应来加速老化,而对硅橡胶主链几乎无影响.此外,在紫外老化初期硅橡胶性能下降较快,但经一段时间后变化趋于平缓.     

硅橡胶憎水迁移性机理试验分析

论文通过对液体硅橡胶和固体硅橡胶憎水迁移性能的比较，验证了硅橡胶憎水迁移性机理，并通过试验，分析了憎水性对复合绝缘子湿闪电压的影响。     

Effect of specimen configuration on deterioration of silicone rubber for polymer insulators in salt fog ageing test

The paper investigates the effects of specimen configuration on the deterioration of silicone rubber insulators in a salt fog ageing test. A cyclic salt fog ageing test was conducted on three types of high-temperature vulcanized silicone rubber (HTV SiR) specimens: two types of insulators having sheds, and plain rods without sheds. The test was based fundamentally on the CIGRE WG 15-04 specifications. After 50 test cycles, the three types of specimens showed different degrees of surface deterioration. Erosion on the straight shed insulator was more severe than that on the alternate shed insulator even though the two had the same leakage distance. No erosion was observed on the rod-type specimens, which had shorter leakage distances than the insulator-type specimens.     

Development of composite insulators in China

The development of composite insulators in China dates back to the early 1970's. In the 1990's they have become widely used in China. At present, up to 600000 composite insulators are operating on 35 to 500 kV ac overhead transmission lines. They are to be introduced into the ±500 kV HVDC transmission schemes. In China all composite insulators in service are silicone rubber and are operating in various contamination conditions. They have successfully and efficiently avoided serious pollution flashover, which occurred frequently when conventional ceramic insulators were used, and radically reduced the maintenance cost of transmission lines in pollution areas. Study of composite insulators is very active in China. The main aspects include properties of materials such as silicone rubber and fiberglass reinforced polymer (FRP) rods, electrical and mechanical performance, aging as well as evaluation and inspection of composite insulators. These fruitful works greatly promote the development of composite insulators in China     

高压输电线路复合绝缘子发热机理的研究

借助于红外热像仪在实验室对含有模拟缺陷的复合绝缘子和来自现场的含有真实缺陷的复合绝缘子拍摄热像图,并与电场强度分布测量结果及解剖结果进行比较分析,研究了复合绝缘子发热的机理,指出内部局部放电引起发热,渗入缺陷的水分带来的介质损耗引起发热,护套严重老化、绝缘电阻下降引起电阻损耗发热这三种发热机理是引起复合绝缘子发热的主要原因,输电线路中的复合绝缘子的发热机理以第三种为主,该研究结果将有利于判断复合绝缘子内部的绝缘缺陷长度及严重程度.