大型电机高导热主绝缘材料发展及应用状况——BN填料对环氧胶黏剂性能影响分析

Development and Application of High Thermal Conductivity Main Insulation Materials for Large Generator——Influence of BN Filler on Properties of Epoxy Adhesive

大型发电机高导热主绝缘材料中最重要的成分是高导热环氧胶黏剂,BN粉体作为高导热环氧胶黏剂的重要组分,在提高环氧树脂导热性能的同时,对其他性能也会产生影响。本文对国内外关于高导热主绝缘材料的研究成果进行了分析总结,发现BN粉体能有效抑制BN/环氧复合材料内空间电荷的产生和聚集,并且降低BN/环氧复合材料的空间电荷的阈值电场;BN粉体的加入会降低环氧/BN复合材料的电气强度,相同BN质量分数下,微米BN/环氧复合材料的电气强度更低;相同BN质量分数下,纳米级BN比微米级BN能更有效地降低复合材料的电导率;对复合材料表面进行充电处理会降低材料表面闪络电压值。并提出了国内大型发电机主绝缘材料中的高导热胶黏剂的研究方向。

The most important component of high thermal conductivity main insulation material for large generators is high thermal conductive epoxy adhesive.As an important component of high thermal conductive epoxy adhesive,BN powder can improve the thermal conductivity of epoxy resin,but it would affect other properties.In this paper,the researches of high thermal conductivity main insulation materials were analyzed and summarized.It was found that BN powder can inhibit the generation and aggregation of space charge in BN/epoxy composites effectively,and reduce the threshold electric field of space charge in BN/epoxy composites.The addition of BN powder could reduce the electric strength of BN/epoxy composites,under the same BN mass fraction,the electric strength of micron BN/epoxy composites was lower,and the conductivity of the composites could be reduced more effectively by nano BN than by micro BN.The surface flashover voltage of the composite decreased after charging on its surface.Then the research direction of high thermal conductivity adhesives in the main insulation materials for large generators in China was proposed.