Study on the impact of initial moisture contents on ageing characteristics of transformer oil-paper insulation

摘要

In order to evaluate the influence of different initial moisture contents for aging characteristics and their internal relations with other factors, this paper designed an accelerated thermal aging experiment, in which the oil impregnated paper made with different moisture content under laboratory conditions. Firstly, the samples measured results were simulated by using Matlab to obtain the fitting curve; then, through the fitting curve at different temperatures, this paper studied the impact of initial moisture contents on oil-paper insulation; finally, this paper interpreted the moisture contents on the impact of the thermal aging characteristic parameters and frequency domain dielectric properties. The research results show that the effect of moisture and temperature on oil-paper insulation aging is not a simple superposition, but mutual coordination, mutual restraint; both higher temperature and more moisture contents will increase the rate of acids, but moisture content can affect the distribution ratio of acids in oil-paper insulation; the moisture content of oil-paper insulation system have a great influence on acids in oil. In addition, we presented the frequency dielectric spectroscopy features (dielectric constant εtotal) for the diagnosis of moisture content and aging state, and found that εtotal has good relationship with moisture content.