Two Factors Failure Model of Oil-Paper Insulation Aging under Electrical and Thermal Multistress

  • Li, Jian ;
  • Wang, Yan ;
  • Bao, Lianwei
  • Received : 2013.08.05
  • Accepted : 2013.10.14
  • Published : 2014.05.01


Converter transformers play important roles in high-voltage direct current transmission systems. This paper presents experimental and analysis results of the combined electrical and thermal aging of oil-impregnated paper at pulsating DC voltages. Breakdown voltages and time-to-breakdown of oil-paper specimens were measured by using short-time and constant-stress tests. The breakdown characteristics of combined electrical and thermal aging on insulation system were discussed. According to the relationship between failure time and aging temperature, the two-parameter Weibull model was improved. On the basis of the competing risk algorithm and the improved Weibull model, the two factors failure model was calculated. And the influence of temperature in the insulation system has been analyzed. This model performs better than the two-parameter Weibull model when both time and temperature are considered as variables in estimating the lifetime of oil-paper insulation.


Converter transformer;Oil-paper insulation;Combined electrical and thermal aging;Pulsating DC voltages;Two factors failure model


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