Follow-up of distribution transformers

A distribution transformers´ load is characterised by a slow but continuous increase from year to year. Therefore, one has to check that the load does not exceed the technical limits of the transformer but also one has to decide on the best economical moment to make a replacement by a larger transformer. In this report, the authors consider first the technical criteria that have to be considered for the follow-up of the transformer load and the determination of the limit situations where an action has to be taken to avoid excess loading. Futher, the authors look for the opportunity to make savings by anticipating the replacement of the transformer by a unit of higher rating. Finally, possible monitoring methods are briefly commented