Reliability evaluation method for oil-paper insulation in power transformers

Abstract

The overall life of oil-immersed power transformers depends on the long-term life of the oil-paper insulation system throughout continuous operation. Studying the reliability assessment methods for oil-paper insulation can help determine the reliability level of power transformers accurately, and ensure their safe and stable operation. In the present paper, the life of oil-paper insulation is proven to obey the Weibull distribution under eight different temperatures set by the Weibull reliability probability paper; the failure mechanisms of the different temperatures are highly consistent. The Weibull distribution reliability curve cluster of oil-paper insulation is plotted under different temperatures by which an oil-paper insulation reliability assessment method is proposed. Lastly, the statistical validation experiment of the proposed method is conducted, which proves its theoretical validity. Thus, the present study puts forward a simple and effective method for the oil-paper insulation reliability assessment of power transformers under different temperatures at different life stages. © 2011 by the authors.