为了有效监控绝缘油的运行状态,采用定量分析方法探讨了微量水分对绝缘油表面张力的影响规律。通过配制不同微水含量的绝缘油样,对每组油样进行表面张力测试,然后对油样进行红外光谱扫描,获取了油样中水分在特征波数处(1 640,3 400,3 450,3 615 cm-1)的吸光度值。分析了油液中2,6-二叔丁基对甲酚(T501)等添加剂对油样表面张力变化规律的影响。结果表明: 油样中水分含量与水分特征吸光度值之间有较好的相关性(相关系数分别为0.964 1,0.984 8,0.984 5,0.944 0),油样表面张力和1 640,3 400,3 450,3 615,3 650 cm-1波数处油样吸光度值的变化亦均呈现良好的正相关性。建立了油样表面张力与特征波数处油样吸光度值的多元线性回归模型,拟合精度为0.992 8;根据模型得到的表面张力计算值与实际测量值误差为-0.07~006%,吻合性较好。文中的实验可为含微水绝缘油的表面张力检测提供理论支撑。

To monitor the operating status of insulating oil effectively,the affecting law of trace water on the interfacial tension of insulating oil was investigated by a quantitative method. By making up a series of oil samples with different trace water contents,the interfacial tension of every group of oil sample was measured and its mid-infrared spectrum was scanned. Then,the absorbance values of oil samples at the characteristic wave number of water molecules (1 640 cm-1,3 400 cm-1,3 450 cm-1,3 615 cm-1) were obtained and the influence of the 2,6-Di-tert.-butyl-p-cresol (T501),a kind of additive in oil samples,on the interfacial tension was analyzed. The results show that the trace water contents in oil samples are dependent on water characteristic absorbance values,which can be up to 0964 1,0.984 8,0.984 5 and 0.944 0. Moreover,there is a good positive correlation between the trace water contents in oil samples and the changes of absorbance values of oil samples at 1 640 cm-1,3 400 cm-1,3 450 cm-1,3 615 cm-1,3 650 cm-1. According to these data,a multiple linear regression model with the goodness fit of 0.992 8 was constructed. The error between calculated values and measured values of the interfacial tension varies from -0.07% to 0.06%,shows a good coincidence. This research supports the measurement of interfacial tension for insulating oil in theory.