A Monte Carlo approach for calculating the thermal lifetime of transformer insulation

This paper presents an accurate method for estimating the thermal lifetime of solid insulation in a power transformer. The method estimates the ambient temperature using the monthly average ambient temperature and the monthly solar clearness index. The average daily load curve and the standard deviation for each hour in the daily load curve are used to model the transformer load. The uncertainties associated with the transformer load and the ambient temperature are used to simulate the transformer artificial history using Monte Carlo technique. This artificial history is used to estimate the average lifetime of the transformer solid insulation. The method is tested on a real field transformer data taken from a local utility. The outcome of the test showed that the proposed method provides reliable results.