Assessment The Overall Health Condition of Transformer Using Health Index and Critical Index Approach: TNB Grid Case Study

The reliability and availability of the electrical network is highly much depending on the reliability of the installed high voltage equipment. Transformer is one of these critical assets and its failure can cause major downtime in the electrical supply and result in the revenue losses to the utilities or plant operator. Over the last decade, condition-based maintenance has been actively engaged as the maintenance regime for the maintenance of in-service power transformer. As such, the basic and advance diagnostic testing has been used to diagnose and assess the condition of the transformers. A large utility typically has in excess of a thousand power transformers and prioritizing the maintenance of the transformer is important to optimize the operational cost and at the same time avoid the unplanned outages. This paper presented the method on assessing the overall health condition of the transformer using combination of health index and criticality index to prioritize the strategic decisions on the transformer and a case study in Tenaga Nasional Berhad (TNB) Malaysia.