基于等离子体处理的硅橡胶憎水恢复物理模型及评价方法研究  

Study on the Physical Model and the Evaluation Method for the Hydrophobic Recovery of Silicone Rubber Based on the Plasma Treatment

作　　者：彭向阳 汪政 黄振 杨粤 何春清[2] 方鹏飞[2] PENG Xiangyang;WANG Zheng;HUANG Zhen;YANG Yue;HE Chunqing;FANG Pengfei(Guangdong Key Laboratory of Electric Power Equipment Reliability(Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.),Guangzhou 510080,Guangdong Province,China;College of Physics and Technology,Wuhan University,Wuhan 430072,Hubei Province,China)

机构地区：[1]广东省电力装备可靠性企业重点实验室(广东电网有限责任公司电力科学研究院),广东省广州市510080 [2]武汉大学物理科学与技术学院,湖北省武汉市430072

出　　处：《中国电机工程学报》2021年第18期6481-6492,共12页Proceedings of the CSEE

基　　金：中国南方电网公司科技项目(GDKJXM20200403,GDKJQQ20161197);中国博士后科学基金(2020M682609)。

摘　　要：憎水恢复性是硅橡胶复合绝缘子的特有性能,为保持电网输变电设备外绝缘水平和安全稳定运行提供了重要保障。目前,针对复合绝缘子运行放电工况下表面憎水性减弱及恢复特性,缺少快速有效的定量评估方法。该文利用等离子体处理方法模拟复合绝缘子硅橡胶在运行放电工况下憎水性减弱及恢复现象,基于小分子扩散理论和菲克第二定律建立等离子体老化后的硅橡胶表面憎水恢复的动态物理模型,并通过数学推导得出硅橡胶小分子扩散系数D的计算公式。实验发现,仅经过3min的等离子体处理,硅橡胶表面就转变为完全亲水,且小分子在硅橡胶无机硅氧层中的扩散系数D数量级为10-16 cm^(2)/s。对比等离子体法与涂污法发现,两者对同系列试样的检测结果趋势一致,具有等效性。气相色谱与质谱联用法试验结果表明,硅橡胶中无机填料氢氧化铝(aluminum hydroxide,ATH)的含量越高,硅橡胶中有机小分子总浓度就越低,当硅橡胶中ATH含量增加时,其憎水恢复性则减弱。等离子体处理法测试得到的小分子扩散系数D可用于定量评价运行复合绝缘子硅橡胶的憎水恢复性。Hydrophobicity recovery is the unique property of the silicone rubber composite insulator, and this property provides an important guarantee for maintaining the external insulation level of power transmission and transformation equipment, which is vital for the safety and stable running of the power grid. At present, it still lacks the efficient and quantitative method to evaluate the silicone rubber’s hydrophobicity recovery property under running discharge conditions. In this paper, plasma was used to mimic the corona discharge occurred in high voltage running condition of the composite insulator to study the hydrophobicity loss and recovery process of silicone rubber. Based on the low molecular weighted siloxanes(LMW) diffusion theory and the Fick’s second law, we established the physical model to shed light on the surface hydrophobicity recovery of silicone rubber. Moreover, the formula to calculate the LMW’s diffusion coefficient D was educed by using the skills of mathematical approximation. The experiment results show that it takes only 3 minutes to modify the hydrophobic silicone rubber surface into completely hydrophilic. The value of LMW’s diffusion coefficient D in the silica-like layer of silicone rubber is on the order of 10-16 cm^(2)/s. To compare the plasma treatment method with the pollution method, it is found that these two methods are equivalent, because the test results for the same series of samples using these two methods are in the same trend. Data obtained by the gas chromatography-mass spectrometry(GC-MS) indicate that, the total concentration of LMW in a silicone rubber decreases with the added aluminum hydroxide(ATH) in its bulk. Moreover, as the weight fraction of ATH increases in a silicone rubber, its hydrophobicity recovery rate decreases. The LMW’s diffusion coefficient D obtained by plasma treatment method can be used as a parameter to quantitatively evaluate hydrophobicity recovery rate of a silicone rubber.

关 键 词：等离子体处理 硅橡胶 憎水恢复性 菲克扩散 小分子硅氧烷 复合绝缘子 

分 类 号：TM85[电气工程—高电压与绝缘技术]