摘要
电力变压器在运行过程中绝缘纸会出现热老化现象,而老化产生的水分又会进一步加速绝缘纸的热老化,故绝缘纸的老化状态在很大程度上决定着变压器的使用寿命,所以提升绝缘纸的耐热老化性能对变压器的安全运行具有很重要的意义。通过建立纤维素/水模型,胺类(双氰胺、三聚氰胺和聚丙烯酰胺)改性的纤维素/水模型,运用分子摸拟技术从力学特性、水分子扩散系数和纤维素的玻璃化温度等角度研究了胺类物质对纤维素耐热老化性能的改善效果。同时,将三种胺类添加到绝缘纸中制备了改性绝缘纸,并将其与普通绝缘纸一起在110℃下进行加速热老化试验,然后定期测量普通绝缘纸及改性绝缘纸的聚合度和水分含量。模拟结果表明,胺类改性纤维素/水模型中纤维素在变压器运行温度范围内力学性能得到提升,水分子运动剧烈程度弱于纤维素/水模型,其玻璃化温度较纤维素/水模型提高了41K。试验结果表明,随着热老化时间的增长,胺类改性绝缘纸的聚合度下降速度要比普通绝缘纸的缓慢,且其水分含量也相对较少。模拟分析与试验测试结果均表明胺类物质的加入对绝缘纸纤维素的耐热老化性能具有较好的提升效果。
The thermal aging phenomenon of insulation paper occurs during transformer operation, and the water produced by oil-paper aging accelerates the aging of insulation paper conversely. Insulation paper aging determines the life of transformer to a large degree. Thus, research on insulation paper improvement is very significant to the safe operation of transformer. In this paper, two models were established and simulated, which are respectively the model of cellulose with water and the model of cellulose with water, Dicyandiamide, Melamine, and Polyacrylamide. The mechanical properties, diffusion coefficients of water, and glass transition temperatures of cellulose in different models were measured to study the improvement of amine on the thermal stability of cellulose. On the other hand, the modified insulation paper was developed by adding three kinds of amine into the cellulose insulation paper. Then the modified insulation paper and the non-modified paper samples were both aged under 110℃, where the DP of cellulose as well as the water content was measured regularly. The simulation results showed that, the mechanical properties of the two established cellulose models were improved. Herein, the degree of activity of water molecular in the amine modified model decreased, and the glass transition temperature of the amine modified model increased by 41 K. The experiment results showed that, as the aging time increased, the DP of cellulose decreased slower and the water content in amine modified paper was less than those in the unmodified sample. The simulation and experiment both indicated that the thermal aging performance improved a certain degree by adding the amine into cellulose insulation.
出处
《电工技术学报》
EI
CSCD
北大核心
2016年第10期68-76,共9页
Transactions of China Electrotechnical Society
基金
国家自然科学基金青年基金(1107103、51507144)
重庆市自然科学基金(cstcjj A90013)
中央高校基本科研业务费重点项目(XDJK2014B031)资助
关键词
变压器
绝缘纸
纤维素
热老化
模拟
Transformer
insulation paper
cellulose
thermal aging
simulation
