Improvement of lifetime model on accelerated thermal aging of oil-paper.

In order to improve the lifetime time model of oil-paper to obtain the more accurate prediction results, the influence of initial moisture contents and temperatures on aging properties of oil-paper was investigated. Firstly, oil-paper samples with four different moisture contents were aged at three temperatures. Degree of Polymerization (DP) of paper was measured as indicator of aging degree. The variation of DP with aging time was studied by introduction of kinetic equation of cellulose degradation accumulation. Secondly, based on the time-temperature superposition (TTSP) method, a time-temperature-moisture superposition (TTSMP) method was proposed to improve the lifetime model. It is indicated that by comparing with previous lifetime model, the merit of the improved one is that not only temperature but also initial moisture content in paper is considered, which is helpful for making more rational estimation of insulation lifetime during long time aging. [ABSTRACT FROM PUBLISHER]