基于绝缘纸电导率定量评估绝缘纸含水量的研究

定量评估油纸绝缘系统中绝缘纸的含水量,能有效为变压器干燥提供决策依据,延长变压器的使用寿命。极化/去极化电流法能无损检测油纸绝缘系统的电导率,文中基于极化/去极化电流(PDC)测量方法,采用极化/去极化电量差计算出绝缘纸电导率,研究了不同含水量浸油绝缘纸电导率的变化规律;并对比了电导电流法与极化/去极化电量差法计算系统电导率时的误差;最后应用电量差法求出了绝缘纸的电导率,采用最小二乘法对绝缘纸电导率与水分含量进行拟合,获得了绝缘纸电导率与绝缘纸含水量之间的定量关系。研究结果表明:电量差法比电导电流法的计算精度更高,绝缘纸的电导率与水分含量呈指数函数关系,因而绝缘纸电导率可定量评估绝缘纸中的含水量。

Study on Quantitative Evaluating Water Content of Insulating Paper Based on Conductivity of Insulating Paper

To quantitatively evaluate moisture content in insulating paper in oil paper insulation system,the polarization/depolarization current(PDC)measurement method is employed for the conductivity of oil immersed insulating paper.The conductivity of the insulating paper is calculated via polarization/depolarization charge difference,and the variation of the conductivity of the insulating paper with different water content is analyzed.Moreover,the calculation error of the conductivity between the conductance current method and the polarization/depolarization charge difference method is discussed,and the quantitative relationship between conductivity and moisture content of the insulating paper is fitted by the least square method.The results show that:the calculation accuracy of the charge difference method is higher than that of the conductance current method,and the relationship between conductivity and moisture content of the insulating paper is an exponential function,therefore the conductivity of the insulating paper can be used to evaluate the moisture content of the insulating paper quantitatively.