特高压换流变环氧浸渍纸干式套管，是我国特高压直流设备国产化的瓶颈，特别是极端工况与试验条件下、玻璃化转变过程中，环氧/纸复合材料中的空间电荷特性和绝缘破坏的机理，成为影响其电气性能的关键因素。因此，本项目针对我国特高压直流干式套管的关键科学问题，1）建立一套高温（可达120℃）高场强（可达100kV/mm）电声脉冲法空间电荷测量系统，改造环氧试样真空浇注装置；2）开展高温高场强下环氧/纸中空间电荷分布测量，重点探索玻璃化转变影响环氧/纸中电荷输运、电场分布、介电性能和绝缘破坏的内在机理；3）分析温度、场强、电极、制备工艺对空间电荷产生、分布、迁移的影响，提出抑制空间电荷效应、改善介电性能的方法。本项目可为我国自主研制特高压直流套管的材料研发、绝缘结构优化和绝缘处理工艺改进，提供设计和理论依据，具有重要的工程应用背景。

The epoxy-impregnated paper dry bushing for ultra high voltage (UHV) converters is the bottleneck of the domestication of UHVDC equipment. The space charge characteristics and the mechanism of dielectric breakdown of the epoxy/paper composite is a key factor to affect its electrical properties, especially under extreme operating conditions and test conditions, or during the glass transition process. Aimed at this key scientific issues for UHVDC dry bushing, the main study content has the following several points: 1) to establish a set of pulsed electro-acoustic (PEA) space charge measurement system for high temperature (up to 120 C) and high electric strength (up to 100 kV/mm) tests, and to modify system of the eposy samples vacuum casting; 2) to measure the space charge distribution in epoxy/paper at high temperature and high electric strength, and to focus on the internal mechanism of the glass transition affecting the charge transport, electric field distribution, dielectric properties and dielectric breakdown of the epoxy/paper; 3) to analyze the influence of temperature, electric strength, electrode, and preparation process on the space charge distribution, and to propose a method to suppress the space charge effect and improve the dielectric properties. This study may provide a design and theoretical basis for the materials research and development, insulation structure optimization, and the improvement of insulation treatment process of China's domestic UHVDC bushing, thus has an important engineering background.