变压器绝缘纸板的纳米改性及其对复合电压下油纸绝缘电场分布均化作用的研究

Converter Transformer is the key equipment in HVDC power transmission system. Under the working conditions, the valve side windings withstand the composite voltage comprised of AC, DC & AC and polarity reversal. In order to solve the problems of non-uniform electric field distribution under DC voltage caused by the resistivity difference between the oil and the pressboard, the electric field distortion on account of space charge accumulation, and electric field strength increasing in the oil gap under polarity reversal voltage, this project starts with the insulation material modification via the method of mixing inorganic nano-materials into pressboard to regulate the pressboard resistivity, to realize the resistivity matching between oil and pressboard, and to decrease resistivity changing difference between oil and pressboard due to temperature variation. The project attempts to restrain the space charge accumulation in the pressboard and make pressboard have the nonlinear resistivity characteristics, to realize homogeneous distribution of the electric field automatically in the key insulation parts of converter transformer. The project aims at seeking the rules of nanoparticle influence on the pressboard resistivity and breakdown strength, and exploring the mechanism of the nanoparticle effects on the space charge transportation, storage and the interfacial polarization in the pressboard. The research results can be used to improve the electric field distribution in oil-paper insulation and enhance the operation stability of converter transformer.

换流变压器是特高压直流输电系统中的重要设备，运行时其阀侧绕组绝缘将承受交流、交直流叠加和极性反转等电压的作用。为解决由于油纸绝缘电阻率差异导致的直流电压下油纸绝缘电场分布不均匀、空间电荷积聚引起的油纸绝缘中电场畸变以及极性反转电压作用下的油隙电场强度升高等问题，本项目拟从材料改性方面入手，通过无机纳米掺杂手段来调控绝缘纸板的电阻率，使油纸复合绝缘中两种绝缘材料的电阻率达到匹配，并降低由于温度变化所引起的油纸绝缘电阻率变化的差异；同时通过无机纳米掺杂手段来抑制绝缘纸板中的空间电荷，并使绝缘纸板具有非线性特性，以实现换流变压器关键绝缘部位电场分布的自动均化。项目旨在寻求无机纳米掺杂对绝缘纸板电阻率及击穿场强的影响规律，探索纳米掺杂对绝缘纸板中空间电荷的输运、存储及界面极化的影响机理。研究成果对改善换流变压器油纸绝缘电场分布，提高其运行可靠性具有重要的理论和实际价值。

换流变压器是特高压直流输电系统中的重要设备，运行时其阀侧绕组绝缘将承受交流、交直流叠加和极性反转等电压的作用。为解决由于油纸绝缘电阻率差异导致的直流电压下油纸绝缘电场分布不均匀、空间电荷积聚引起的油纸绝缘中电场畸变以及极性反转电压作用下的油隙电场强度升高等问题，本项目从材料改性方面入手，通过无机纳米掺杂手段来调控绝缘纸板的电阻率，使油纸复合绝缘中两种绝缘材料的电阻率达到匹配，并降低由于温度变化所引起的油纸绝缘电阻率变化的差异；同时通过无机纳米掺杂手段来抑制绝缘纸板中的空间电荷，并使绝缘纸板具有非线性特性，以实现换流变压器关键绝缘部位电场分布的自动均化。项目旨在寻求无机纳米掺杂对绝缘纸板电阻率及击穿场强的影响规律，探索纳米掺杂对绝缘纸板中空间电荷的输运、存储及界面极化的影响机理。研究成果对改善换流变压器油纸绝缘电场分布，提高其运行可靠性具有重要的理论和实际价值。