Methods have been developed to optimise transformer life through the better understanding and measuring the water content and life remaining of paper insulation.
The main two causes for transformer failure are overload, which can occur if the insulation is too wet, and the age of paper insulation can be evaluated using software tools. Researchers at The University of Queensland, in close cooperation with utilities, have developed such a tool which will provide advance warning when failure may occur.
The developed model is focused on the estimation of water content in oil to calculate the remaining life of paper insulation and is superior to the existing IEC 60076 and IEEE models for ageing because it takes more variables into account.
Mathematical modelling of water content is provided, which shows its close relation to the temperature distribution across insulation within a transformer. Therefore, algorithms to determine the water content of the paper at the hottest points within the transformer are investigated, as insulation will deteriorate here faster. The newly developed technique by researchers shows a very close correlation with the existing offline techniques. Moreover, the software tool enables an accurate determination of the life remaining under different operating conditions. This tool will help asset engineers to accurately measure the water content and residual life and and make optimal decisions regarding transformer asset management.