Assessment on Oil-Paper Insulation Aging of Transformer Based on Dielectric Response Model

摘要

For nondestructive assessment of insulation aging in power transformer, dielectric response technology is usually used to evaluate the oil-paper insulation aging. In this paper, a quantitative evaluation method of insulation aging based on Davidson-Cole model is proposed. The oil-paper insulation equivalent Debye model parameters of transformer are extracted by exponential function fitting. According to the complex permittivity of oil-paper insulation, the parameters of Davidson-Cole model are extracted by fitting algorithm. Under laboratory conditions, accelerated thermal aging test are carried out. The quantitative relationship between Davidson-Cole model parameters and aging of oil-paper insulation is analyzed. The experimental results show that the Davidson-Cole model parameters are directly related to the aging time. It is found that the parameters [i and At: of the Davidson-Cole model gradually decreases and the parameter x gradually increases with the polymerization degree of oil-impregnated paper. Therefore, according to the quantitative characterization of the model parameters, the aging of transformer oil-paper insulation can be effectively evaluated, which is helpful to realize the nondestructive testing of polymerization degree in oil-impregnated pressboard (paper) power transformer.