Statistical analysis of power transformer component life time data

With statistical analysis it is possible to describe the ageing processes of power transformers components statistically. Because of the complexity of power transformers it is interesting to show the failure behaviour of the different components. As input for the analysis a population of power transformers with different ratings, designs and makes is used. From the reported failures the different failure modes of the components are distinguished. The failure data is fitted with mathematical statistical distributions and its parameters can be estimated. From the analysis it can be seen in which life phase the components are and what can be expected for the future regarding failures of some transformer components. The results can be used to determine if there is a reason for concern in the next coming years and if replacement or maintenance is necessary to secure a reliable network operation. It can also help to determine in what way a population of spare transformers is needed.