State-of-the-art review on asset management methodologies for oil-immersed power transformers

Owing to their vital function and high cost, oil-immersed power transformers represent key links in electricity grids. While extensive effort has been invested by industry in developing various condition monitoring and fault diagnosis apparatuses, it is not economically feasible to apply rigorous inspection and extensive testing to all power transformer fleets in the network. The fundamental purpose of asset management is to balance cost and reliability of the system. Maintaining the reliability of power transformers involves regular condition monitoring, fault diagnosis and overall health assessment. In addition, estimating the remnant life of power transformers can help asset managers plan capital investments. By reviewing the methods used for power transformer asset management, assets integrity team can decide the most suitable maintenance strategy for each transformer in the network. This paper is aimed to present state-of-the-art review for power transformer asset management, health assessment and remnant life methodologies. While many review papers on transformer fault diagnosis have been published in the literature, not much attention was given to present a state-of-the-art review on the three modules of the transformer asset managements that include fault diagnosis, reliability assessment and life management modules. These three modules are comprehensively presented in this paper that also presents future challenges and improvement in this field of research.