Correlation between temperature gradient and space charge in an oil impregnated pressboard submitted to an electric field

An automatic experimental setup has been performed in order to make long term experiments on oil impregnated pressboard sample submitted to both electric field and temperature gradient. The evolution, in terms of time, of the potential distribution is measured inside the impregnated pressboard sample at the application of an electric field for different temperature gradients. Four temperature gradients have been tested and three different electric fields. The space charge evolution is measured during around two hours after each temperature gradient application for a given electric field. The analyze of the charge development can then be used to understand the charge accumulation in pressboard due to flow electrification in transformer during temperature stabilization.