A new method for systematically estimating health index, probability of breakdown, and remaining life for power transformers is presented in this article. The method combines three basic models; a physical winding degradation model, a health index model based on condition monitoring data combined with expert judgement, and a statistics-based end-of-life model. The statistics-based model uses data from a database of scrapped transformers under development in Norway. Combining the first two models with the statistics-based model, an individual and condition-dependent probability of breakdown is obtained. From this, the expected remaining life is calculated. Finally, the stochasticity of the method is utilized for optimization of maintenance and replacement. The method hence provides key decision support for transformer managers, enabling them to identify transformers in poor condition, and to follow-up and prioritize transformers for maintenance and replacement. The proposed method has been implemented in a transformer asset management tool for Norwegian utilities. The usefulness of the method is illustrated by applying it to selected transformers from one of these utilities. Finally, important limitations, uncertainties, and further improvements are discussed.

中文翻译：

---

电力变压器的健康指数、风险和剩余寿命估计

本文介绍了一种系统估计电力变压器健康指数、故障概率和剩余寿命的新方法。该方法结合了三个基本模型；物理绕组退化模型，基于状态监测数据结合专家判断的健康指数模型，以及基于统计的报废模型。基于统计的模型使用挪威正在开发的报废变压器数据库中的数据。将前两个模型与基于统计的模型相结合，可以获得个体和条件相关的故障概率。由此计算预期剩余寿命。最后，利用该方法的随机性来优化维护和更换。因此，该方法为变压器管理器提供了关键的决策支持，使他们能够识别状况不佳的变压器，并跟踪和优先考虑变压器的维护和更换。所提出的方法已在挪威公用事业公司的变压器资产管理工具中实施。该方法的实用性通过将其应用于这些公用事业之一的选定变压器来说明。最后，讨论了重要的局限性、不确定性和进一步的改进。