基于直接氟化调控环氧树脂的表面电学性能及氟化层的老化性能研究

Electric charges are easily accumulated on surface of an epoxy resin insulator when it is subjected to a direct current high voltage, and suppression of the surface charge accumulation is the key to develop the gas-insulated switchgears (GIS) and gas-insulated lines (GIL) used for direct current power transmission. In order to suppress the surface charge accumulation on the epoxy resin insulator, in the research project, its surface electrical properties will be modulated by surface fluorination of the epoxy resin insulator. The influences of fluorination conditions (time, temperature, and concentration of fluorine gas etc.) on the character (composition, structure, and morphology) and thickness of the surface layer are first investigated to reveal the association of the character and thickness of the fluorinated layer with fluorination conditions. And then the basic electrical properties, surface hydrophobicity, and barrier properties of the fluorinated layer are studied to determine the fluorination conditions under which surface conductivity, surface hydrophobicity, and barrier properties can be effectively enhanced. Afterwards the investigations on corona, thermal and hygrothermal aging properties of the fluorinated layer and on the aging mechanisms are performed to disclose the correlation of the aging properties with the character and thickness of the fluorinated layer. Surface flashover characteristics of the epoxy resin insulator, especially under high voltage direct current, are investigated, and the properties of the fluorinated layer are comprehensively evaluated on the basis of its flashover characteristics and aging properties. Finally, the comprehensive influences of the fluorination and the loading of inorganic particles on surface layer properties will be investigated to enhance flashover voltage and aging properties of the epoxy resin insulator by the greatest extent and to provide experimental and theoretical foundation for the practical applications.

在直流高压作用下环氧树脂绝缘支撑件的表面上易于积累电荷，抑制其表面电荷积累是开发直流输电用气体绝缘开关设备(GIS)和气体绝缘输电线路(GIL)的关键。为抑制环氧树脂绝缘件的表面电荷积累，本课题拟通过表层氟化改性、调控其表面电学性能。首先将研究氟化条件（时间、温度和氟气浓度等）对表层的性状（组成、结构和形貌）和厚度的影响，揭示氟化层的性状和厚度与氟化条件的关联。进而研究氟化层的基本电学性能及表面疏水性和阻挡特性，确立有效提高表面电导率、表面疏水性和阻挡特性的氟化条件。然后研究氟化层的电晕老化、热老化和湿热老化性能及老化机理，揭示老化性能与其性状和厚度的关联性。开展环氧树脂绝缘件（尤其在直流高压下）的沿面闪络特性研究，基于闪络特性和老化性能综合评价氟化层的性能。最后研究氟化与无机颗粒填充对环氧树脂表层性能的综合影响，最大限度地提高其闪络电压和老化性能，为实际应用提供实验与理论依据。

在直流高压作用下环氧绝缘子的表面易于积累电荷，抑制其表面电荷积累是开发直流输电用气体绝缘开关设备 (GIS) 和气体绝缘输电线路 (GIL) 的关键。高电压气体绝缘系统中绝缘子的耐局部放电性能及耐电弧性能的问题，也一直困扰着国内外绝缘子制造商和电力运行管理部门，长期以来为国内外研究者和工程技术人员最为关注的课题之一。为抑制环氧绝缘的表面电荷积累、改善其直流闪络性能及提高其耐放电、耐电弧性能，本项目开展了如下主要研究：1）环氧绝缘的表层氟化改性 — 氟化层的物化特征与氟化条件的关联，2）环氧绝缘氟化表层的基本电学性能和疏水性，3）环氧绝缘氟化表层的耐紫外、耐电晕和耐闪络放电性能，4）表层氟化环氧绝缘的直流和交流闪络性能，5）氟化和Al3O2颗粒填充对环氧绝缘表层性能的综合影响。取得如下重要的结果：1）通过改变氟化条件，环氧绝缘的表层物化特征和基本性能被调控，如、表面电导率能在4个数量级的范围内被调控（增大），2）直接氟化能显著地改善环氧绝缘的耐紫外和耐电晕老化性能，不管这个电晕老化实验是在SF6气、还是在干空气或氮气中，3）直接氟化能显著地改善环氧绝缘的直流闪络性能、能极大地提高环氧绝缘的耐闪络放电降解或起痕能力，尽管它不明显地增加环氧绝缘的交流闪络电压，4）如同纯环氧绝缘的情形，直接氟引起了Al3O2颗粒填充的环氧绝缘相似的性能改善。这些结果对具有潜在的重要的实际应用价值。另外，本项目的拓宽性研究还表明直接氟化对调控硅橡胶和聚对苯二甲酸丁二醇酯的表层性能同样非常有效。