摘要
为了研究植物油对油浸绝缘纸老化速率的影响,本文以25#矿物油纸绝缘和ABB公司生产的BIOTEMP植物油纸绝缘为研究对象,分别开展了加速热老化试验,分析植物油对其老化速率的影响,结果表明植物油可以延缓绝缘纸的老化速率,延长其使用寿命。采用XPS和分子模拟软件分析了造成这种影响的原因,绝缘纸在植物油中热老化具有较大的活化能,水分子与植物油分子之间具有较大的相互作用力,容易被植物油分子束缚,削弱纤维素的水解反应。热老化过程中,植物油对绝缘纸纤维起到化学改性作用,由酯化反应生成的酯基一方面可以更加牢固地束缚水分子,另一方面长链脂肪酸酯化到纤维素上后将与纤维素平行排列,对纤维起到"水屏障"的作用,从而延缓纤维的水解速率。
With the development of new insulation materials, vegetable oil--the best substitute for mineral oil--has gradually been widely used in the liquid insulation of transformers. To investigate the influence of vegetable oil on the thermal aging rate of cellulose paper, kraft paper impregnated with mineral oil and vegetable oil underwent thermally accelerated aging at three different temperatures. degree polymerization (DP) of Kraft paper was measured to indicate the aging degree of insulation paper. The aging rate of paper in mineral oil and vegetable oil was compared quantitatively, and results showed that vegetable oil retarded paper's degradation rate and extended its useful lifetime. The reasons contributing to such phenomenon were analyzed using X-ray Photoelectron Spectroscopy (XPS) and molecular simulation software. Kraft paper in vegetable oil had larger activation energy. Due to the larger interaction force between water and natural ester molecules, water molecule was easily bonded with natural ester, weakening the hydrolysis process of cellulose. Cellulose was chemically modified by natural ester during thermal aging process, and the reactive - OH(hydroxyl) groups on the cellulose became esterified with fatty acid esters. The water molecule was firmly bounded to the ester groups on glucose produced by esterification. The long-chain fatty acid esterified to cellulose was parallel with cellulose chains and acted as a "water barrier" to further weaken the hydrolysis process.
出处
《电工技术学报》
EI
CSCD
北大核心
2012年第5期26-33,共8页
Transactions of China Electrotechnical Society
基金
国家重点基础研究发展计划(973计划)(2009CB724505-1)
重庆市自然科学基金(CSTC,2008BB6172)资助项目
关键词
油纸绝缘
加速热老化
聚合度
X射线能谱
分子模拟
Oil-paper, accelerated thermal aging, degree polymerization, X-ray photoelectronspectroscopy(XPS), molecular simulation