On the states of water and its quantification in oil impregnated power equipments

In this contribution, the different states of water in insulating fluids are presented. It is proposed to separate ldquosolubility limitrdquo and ldquosaturation limitrdquo concepts. It is shown, that confusion of these concepts, results in erroneous interpretation and analysis of the data and, accordingly, in the diagnostic conclusions. The differentiation of water states and consequent analysis methods allows formulating the concept of diagnostics based on water content. The isotherms of water content for some fluids are provided. In view of feature of each of methods of water analysis the equations for calculation of solid insulation humidity and a residual life of solid insulation are given.