Markers of cellulose insulation ageing: Calculation of total methanol quantity in the internal insulation of power transformers

\nThe methods of calculation of methanol quantity in the internal insulation of power transformers (PT) based on the values of its concentration in transformer oil (TO) are considered. The total methanol quantity formed during the operation of PTs allows estimating the degree of degradation of cellulose insulation. We are considering the models for calculation of the total methanol quantity in PT on the base of:\n<list list-content="dash" list-type="bullet"><list-item>literature data characterizing the methanol balance in the cellulose-oil system;</list-item><list-item>data on the reduction of methanol concentration after TO replacement during total overhaul.</list-item></list>\nThe errors analysis on the base of the results of calculations using the models showed that their value can reach 30%. Reduction of errors in the calculation results should be based on a deeper study of the kinetics of methanol sorption processes by cellulose and taking into account the structural features of different types of cellulose insulation in the particular PT.\nThe considered models can be recommended for estimation of total quantity of any dissolved decomposition products of cellulose insulation in TO, which can become an important indicator of technical condition of PT.\n