扩展Debye模型大时间常数与变压器油纸绝缘老化的定量关系研究

摘要

目前,应用极化/去极化电流(PDC)法量化变压器油纸绝缘系统老化状态需深入研究,为了推动该研究工作,通过一系列加速热老化试验以及吸潮试验制备了不同老化状态和水分含量的油纸绝缘样品,测量了样品的PDC图谱;借助扩展Debye电路模型拟合了PDC图谱并获取了模型参数,在深入研究老化对Debye模型参数的影响规律后提出了时域介电特征量扩展Debye模型大时间常数来量化绝缘纸板老化状态.研究结果表明,扩展Debye模型大时间常数与绝缘纸板的聚合度存在较好的指数关系,但与样品的绝缘尺寸无关.%Since how to quantify the aging condition of transformer oil-paper insulation by PDC (Polarization and Depolarization Current) method needs further research,several oil-paper insulation specimens with different aging conditions and different moisture contents are prepared by a series of accelerated thermal aging and moisture absorption experiments,and their PDC diagrams are measured.The extended Debye model is adopted to fit the PDC diagram and the model parameters are obtained.The influence of oil-paper aging on the model parameters is studied,and the time-domain dielectric characteristic parameter,i.e.the large time constant of extend Debye model is proposed to quantify the aging condition of transformer pressboards.Results of research show that,there is better exponential relationship between the large time constant of extend Debye model and DP(Degree of Polymerization) and the large time constant is immune to the insulation size.