Transformer Lifetime Modelling Based on Condition Monitoring Data

Effective transformer lifetime models are of paramount importance for asset management but are hindered by the lack of actual failure data. The paper hence proposes an approach for functional lifetime modelling of power transformers based on condition monitoring data. Transformer’s functional lifetime is proposed to be modelled as following a two-parameter Weibull distribution whose parameters are recommended to be estimated with the maximum likelihood estimation method. An example is presented to show how the proposed approach is applied on a set of field collected transformer data. The derived Weibull distribution is verified with its corresponding non-parametric estimates. The earliest and latest onsets of significant unreliability for the transformer fleet are then obtained from the derived model so as to as general guidance for asset managers to make replacement planning.