Estimation of the lifetime of the electrical components in distribution networks

Due to the large amount of electrical equipment and the costs of an individual diagnosis in distribution networks, a life assessment of the representative electrical components is necessary. For a thorough electro-thermo-mechanical life model of the electrical components, the individual aging phenomena of the representative electrical components as well as the general aging mechanisms of insulating materials are taken into account in this paper. On the basis of the probabilistic approach, the failure probability about possible failure time and the related statistical variables are given in terms of probabilistic failure density, failure rate and failure probability of electrical components. For such a purpose, the relationship between lifetime, electrical stress, mechanical stress and temperature as well as their effects on aging processes and on reliabilities of electrical components are studied. Thereby a new approach is developed for the life assessment of electrical components which supports the decision-making in future deregulation of the electric energy market. Furthermore, the data of historical failure events from distribution networks is collected and evaluated in a special failure statistic. Thus the models can be parameterized with the failure data from practice in distribution networks as a great deal of statistical data is available for the probabilistic assessment. It is demonstrated with the data of some electrical components like conductors, cables, transformers and circuit-breakers that the method is able to assess the lifetime and reliability of electrical components with reasonable and accurate data.