变压器中丁腈橡胶及聚四氟乙烯密封圈溶胀渗漏油的实验研究

Swelling characteristics of butadiene acrylonitrile rubber and polytetrafluoroethylene seal rings used in power transformers

通过溶胀实验，绘制出丁腈橡胶及聚四氟乙烯密封圈因溶胀而产生的质量增长随时间的变化曲线。在此基础上可计算出吸附层厚度；吸附时间；扩散时间；２０ａ漏油量等溶胀特性指标。实验结果表明：１）吸附层厚度基本上与温度无关；２）吸附时间在１９～３０ｈ间；３）２０ａ漏油量最大值为３２３ｇ，占总油重的０．０４％；４）聚四氟乙烯的溶胀漏油特性优于丁腈橡胶。电子显微镜观察表明：老化后丁腈橡胶圈表面产生裂纹，而聚四氟乙烯圈无明显变化。实验研究结果与作者在论文“全密封变压器中丁腈橡胶密封圈溶胀渗漏油的数学模型”中提出的数学模型相吻合，证明了理论模型的正确性。

Curves describing weight increment of seal ring due to swelling with respect to time are obtained in experiments. Swelling characteristics indexes can be calculated applying weight increment curves. Indexes proposed are as follows: thickness of absorbing layer, absorbing time duration, spreading time duration and oil leakage volume. Experimental results show: 1) thickness of asorbing layer is basically independent upon temperature; 2) absorbing time duration is at 19￣30 h; 3) oil leakage volume of butadiene acrylonitrile rubber seal ring during 20 years is 323 g, which is 0.04% of the total oil weight; 4) by swelling characteristics, polytetrafluoroethylene is better than butadiene acrylonitrile rubber; 5) by electron microscope inspection, effect of aging to surface harming of butadiene acrylonitrile rubber is more evident than polytetrafluoroethylene. Experimental results are identical with mathematical model proposed by authers delivered in paper “Mathematical model of swelling characteristics of butadiene acrylonitrile rubber seal rings in full sealed transformers”, and the valitidy of mathemtical model is proved.