摘要
为利用频域介电谱准确分析变压器油纸绝缘状态,引入考虑直流电导率与跳跃电导率的改进DavidsonCole介电模型。运用测量的频域介电谱数据参数化改进Davidson-Cole介电模型,将其转化为非线性优化问题。选用混合蛙跳优化算法对改进Davidson-Cole介电模型参数进行辨识,得到了弛豫时间τ、圆弧不对称度β和直流电导率σ_(dc)等特征参数。研究了老化与受潮对油纸绝缘试样的改进Davidson-Cole模型参数的影响特性,结果表明β与糠醛含量、σ_(dc)与水分含量有着良好的指数关系;τ与糠醛含量、水分含量有着良好的对数关系。通过线性拟合获得了糠醛含量、水分含量与模型参数的量化关系式,其拟合优度较高,因此可利用改进Davidson-Cole模型定量评估变压器油纸绝缘状态。
In order to accurately analyze the state of transformer oil paper insulation using FDS( Frequency-domain Dielectric Spectroscopy),an improved Davidson-Cole dielectric model considering DC conductivity and hopping conductivity is proposed. The Davidson-Cole dielectric model is improved by parameterizing the measured FDS data and then transformed into a nonlinear optimization problem. The mixed frog leaping optimization algorithm is adopted to identify the parameters of the improved Davidson-Cole dielectric model,by which,the characteristic parameters such as relaxation time τ,asymmetry of circular arc β and DC conductivity σdcare obtained. The influences of aging and moisture on the parameters of modified Davidson-Cole dielectric model for oil paper insulation samples are researched. The research results show that β has good exponential relationship with furfural content,σdchas good exponential relationship with moisture content,and τ has good logarithmic relationship with furfural content and moisture content. Quantitative functions of relationship between furfural content,moisture content and model parameters are obtained by linear fitting. These quantitative functions have high goodness of fit,so the improved Davidson-Cole dielectric model can be used to quantitatively evaluate the state of transformer oil paper insulation.
引文
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