The investigation on dispersion of characteristic parameters for assessment of insulating state and economic feasibility in oil-paper insulation diagnosis

The former researches for condition assessment of oil-paper focus on the statistical results of aging factors and diagnostic data, the mechanisms of aging factors and variation law of each characteristics, which can give conclusions of aging status and furthermore, life expectations. However, the questions “How exactly can aging characteristics reflect the aging status”, “To what extent can we believe the diagnostic data” and “How can we choose the precise characteristics to make multi-parameter diagnosis” are still need to be put forward. In this paper the thermal and electrical accelerated aging experiments of oil-paper insulation is put into practice. On the basis of aging test results, in this paper, how the deviation degree of aging characteristic parameters change under the same aging factors are studied, and the multi-parameter diagnosis method is put forward, in which we can see how exactly do parameters reflect the condition status of the insulation. The conclusions are made that more diagnostic parameters may not always benefit and suggestion is given to choose the more precise characteristics in multi-parameter diagnosis.