Power transformers are the most important components of electrical energy supply networks. Although these components have high reliability, failures can occur due to external factors such as short circuits in the grid. Failures can also occur due to ageing effects of the active part, especially the insulation system, or ageing of important accessories such as bushings or on load tap changers. In case of failure, the first action is to identify the type of failure. The aim is to localize the failure itself as well as its root cause.
Repairing a transformer instead of replacing it can substantially reduce investment costs and provide a faster turnaround than buying a new transformer. Furthermore, to maximize the assets technical life, a refurbishment or overhaul can be an intermediate action when no failure has occurred and the ageing of the active part has reached a stage where the continued reliability of the transformer is unacceptable.
For preventive maintenance, refurbishment also known as reconditioning, is a frequent used option, in where equipment is taken to an authorized service workshop for a full inspection, thorough cleaning and individual component analysis and replacement according the maintenance schedule. The reconditioned equipment undergoes complete testing and comes with a warranty.