油纸绝缘系统弛豫响应极化谱函数建模研究

根据绝缘介质弛豫响应特性推导了油纸绝缘系统的集中参数等值电路.将该等值电路转化为运算电路分析,并运用电路叠加定理构建油纸绝缘弛豫响应极化谱的函数表达式,得到了极化谱的复合指数衰减模型.其中各指数衰减项的时间常数为运算电路极点值的负倒数,并且复合的项数与油纸绝缘介质内部弛豫机构数密切相关.模型的提出可以为后续油纸绝缘弛豫响应的拓扑建模奠定基础.再利用该模型对相同电压等级,不同容量、不同运行年限油浸式电力变压器的测试极化谱采用非线性最小二乘方法进行拟合,拟合结果进一步验证了极化谱模型的准确性.

Study on relaxation response polarization spectrum function modeling of oil-paper insulation system

According to the dielectric relaxation response lumped parameter equivalent circuit of oil/paper insulation system was deduced. The equivalent circuit can be converted to operational circuit, on that basis by using circuit superposition theorem function expression of relaxation response polarization spectrum of oil/paper insulation was built, so that the composite exponential attenuation model of the polarization spectrum was got. Among them the exponential decay time constants are negative reciprocal of operational circuit extreme values, and the number of composite item is closely related with oil/paper insulation internal relaxation mechanisms. The model proposed can lay the foundation for subsequent oil/paper insulation relaxation response topology modeling. At last, fit the test polarization spectrum of oil-immersed power transformers with different capacitiy and running years by using nonlinear least square method, and the fitting results verify the accuracy of the polarization spectrum model.