SF6气体绝缘高压直流设备内部绝缘子用新型陶瓷材料特性探索

陶瓷材料具有高导热性、高机械强度,在SF6绝缘高压直流电气设备内具有一定应用潜力。该文探索了一种新型陶瓷材料的电导特性、表面电荷特性、机械特性及耐酸蚀性,并与工程用环氧树脂/Al2O3复合材料进行了对比,研究发现:室温、低场下陶瓷体积电阻率为4.5×1015W×m,且其温度依赖性较环氧复合材料低;正、负极性直流电压下,陶瓷表面均积聚正极性表面电荷,且最大电荷密度仅为0.21pC/mm2,较环氧复合材料低54%;此外,陶瓷材料表现出了较优的机械与耐酸蚀特性。基于材料物化结构的电导机理模型及温度梯度下支柱绝缘子的电场计算结果,进一步验证了陶瓷所具备的优异特性与巨大潜力。研究成果为提升SF6绝缘高压直流电气设备沿面绝缘性能提供了一种新的思路,为新型陶瓷材料的工程应用提供了理论基础。

Exploration on the Characteristics of New Ceramic Materials for Insulators Used in SF Gas Insulated HVDC Equipment

Ceramic material has high thermal conductivity and high mechanical strength. Therefore, ceramic material has application potential in SF6 insulated high voltage DC electrical equipment. The electrical conductivity, surface charge, mechanical properties and acid corrosion resistance of a new type of ceramic material were explored in this paper, and were compared with engineering epoxy-based material. It is found that the volume resistivity of ceramic at room temperature and low field is 4.5×1015Ω·m, and its temperature dependence is lower than epoxy-based material;under positive and negative DC voltages, the ceramic surface accumulates positive surface charges, and the maximum charge density is only 0.21 pC/mm2, which is 54% lower than epoxy-based material;in addition, the ceramic material shows better mechanical and acid corrosion resistance. According to the electrical conductance mechanism model based on the physical and chemical structure and the calculation results of the electric field of the supporting insulator under the temperature gradient, the excellent characteristics and great application potential of ceramic were verified. The research results provide a new idea for improving the surface insulation performance of SF6 insulated HVDC electrical equipment, and provide a theoretical basis for the engineering application of this new type of ceramic material.