水分侵入复合绝缘子影响因素研究

发布时间：2018-07-27 12:49

【摘要】：近年来国内多条线路出现复合绝缘子异常温升和断裂现象,水分可能是引起这些问题的重要因素。因此本文通过吸湿和透湿试验研究了不同因素对水分侵入复合绝缘子的影响。首先使用称重法,研究了配方、老化对硅橡胶和芯棒材料吸湿行为的影响以及温度、湿度、电场对硅橡胶吸湿行为的影响。然后在此基础上,研究了界面粘接强度、界面气隙严重程度对复合绝缘子透湿性能的影响以及复合绝缘子沿串不同位置透湿性能的差异性。吸湿试验结果表明,配方对材料吸湿性能的影响明显。Al(OH)3(ATH)相对含量从ATH0~ATH200变化时,硅橡胶饱和增重率先增后减,当ATH含量为100(即现场复合绝缘子硅橡胶ATH填料含量)时,饱和增重率最大。白炭黑填料对硅橡胶吸湿特性的影响与ATH相似,白炭黑相对含量为100(即现场复合绝缘子硅橡胶白炭黑填料含量)时饱和增重率最大。使用氧化铁着色剂的红色硅橡胶材料比灰色硅橡胶饱和增重率更大。不同厂家的芯棒材料新试样在吸湿性能上存在差异。老化对材料的破坏作用明显,对材料吸湿增重率影响显著。电晕老化后硅橡胶试样的饱和增重率远高于新试样,原因是电子轰击导致孔洞、缝隙大量出现,增加了硅橡胶对水分子的吸附面积,加之硅橡胶材料中的亲水性基团增加,导致材料的吸湿率上升。饱和增重率随着老化时间的增加呈指数上升。湿热老化后芯棒的增重率明显高于新试样。可能的原因是湿热老化过程中环氧树脂基体溶胀、水解导致与玻璃纤维的界面出现脱粘进而形成水分扩散通道。环境因素通过改变扩散条件的剧烈程度来影响材料的吸湿行为。25℃下,随着环境湿度的增加,硅橡胶饱和增重率与湿度呈正比例关系,湿度越大饱和增重率越高。75%湿度下,由于硅橡胶的吸湿过程会放出热量,温度的升高使水分子在硅橡胶中的溶解度降低,温度越高硅橡胶的吸湿能力越弱。2.6k V/cm交流电场对硅橡胶材料吸湿特性无明显影响,2.6k V/cm直流电场对硅橡胶材料吸湿有一定的抑制作用。透湿试验结果表明,空气中的水分可以透过硅橡胶材料、硅橡胶-芯棒界面、芯棒材料后到达芯棒内部。界面粘接强度与复合绝缘子的透湿性能无明显相关性。因物理破坏导致的界面气隙对复合绝缘子透湿影响有限。同支绝缘子沿串透湿性能分布不均匀,透湿速率从高到低依次为高压端、低压端、中压端。
[Abstract]:In recent years, the phenomenon of abnormal temperature rise and fracture of composite insulators occurred in many lines in China, and moisture may be an important factor causing these problems. In this paper, the influence of different factors on water invasion composite insulator is studied through moisture absorption and moisture permeation tests. Firstly, the effects of formula, aging on moisture absorption behavior of silicone rubber and mandrel materials and the effects of temperature, humidity and electric field on moisture absorption behavior of silicone rubber were studied by weighing method. On this basis, the influence of interface bonding strength, interface air gap severity on the moisture permeability of composite insulators and the difference of moisture permeability of composite insulators at different positions along the string are studied. The results of moisture absorption test showed that when the relative content of Al (OH) _ 3 (ATH) changed from ATH0~ATH200 to ATH0~ATH200, the saturated weight of silicone rubber increased first and then decreased, when the content of ATH was 100 (that is, the content of ATH filler of composite insulator in situ). The saturation weight gain rate is the highest. The effect of silica filler on the moisture absorption characteristics of silicone rubber is similar to that of ATH. The saturation weight gain rate of silica filler is the highest when the relative content of silica is 100 (i.e. the content of silica filler of silicone rubber silica in situ composite insulator). The red silicone rubber material using iron oxide colorant has higher saturated weight gain than gray silicone rubber. The new mandrel materials from different manufacturers have different hygroscopicity. The effect of aging on the damage of the material is obvious, and on the rate of moisture absorption and weight gain of the material is obvious. After corona aging, the saturated weight gain rate of silicone rubber sample is much higher than that of new sample. The reason is that electron bombardment results in holes and large number of cracks, which increases the adsorption area of silicone rubber to water molecules and increases the hydrophilic group in silicone rubber material. The moisture absorption rate of the material increases. The saturated weight gain rate increased exponentially with the aging time. The weight gain rate of the mandrel is obviously higher than that of the new specimen after hygrothermal aging. The possible reason is the swelling of epoxy resin matrix and hydrolysis of epoxy resin during hygrothermal aging, which leads to the debonding of the interface with glass fiber and the formation of water diffusion channel. Environmental factors influence the moisture absorption behavior of the materials by changing the intensity of diffusion conditions. With the increase of environmental humidity, the ratio of saturated weight gain of silicone rubber is proportional to the humidity. The higher the humidity is, the higher the saturated weight gain rate of silicone rubber is, and the higher the humidity is, the higher the humidity is. Because the moisture absorption process of silicone rubber releases heat, the increase of temperature reduces the solubility of water molecules in silicone rubber. The hygroscopicity of silicone rubber with higher temperature is weaker. 2.6k V/cm alternating current field has no obvious influence on the moisture absorption characteristics of silicone rubber material. The 2.6k V/cm DC field has a certain inhibition effect on the moisture absorption of silicone rubber material. The results of moisture permeation test show that the moisture in air can pass through the silicone rubber material, the interface between silicone rubber and mandrel, and then the mandrel material can reach the inner part of the mandrel. There is no obvious correlation between the interfacial bonding strength and the moisture permeability of composite insulators. The interface air gap caused by physical failure has a limited effect on the moisture permeability of composite insulators. The distribution of moisture permeability of the same insulator is not uniform along the string. The moisture permeability rate from high to low is high voltage end, low voltage end and medium pressure end.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM216

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