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Component Upgrades are based on Hitachi Energy's decade-long experience in manufacturing and maintaining its products. Regular preventive maintenance helps facilitate forward budget planning for these types of services.

The main concern in aging and the life expectancy of transformers is the condition of the insulation system and key components of the transformer, like the bushing, tap changer, and cooling equipment.

The insulation system, a combination of mineral oil and paper in a transformer, degrades over time, and finally, they lose the capability to withstand the stresses a transformer might see in daily life (short circuits, energizing, vibration, etc.). The lifetime of these organic products in a transformer depends on the insulation's operating temperature, oxygen content, oil acidity, and moisture content. 

It is possible to reverse the aging of mineral oil through oil reclamation that can restore the material properties close to the values when new. The aging of paper insulation, however, is an irreversible process and is considered one of the life-limiting processes of a transformer.

Temperature is mainly dependent on the transformer design, the loading, the cooling facilities, and the ambient temperature.  Cooling overhaul or upgrade is a highly recommended solution for operating the transformer at a lower temperature or for power upgrade purposes. Moreover, this alternative has significant cost savings versus new transformer replacement. 

Bushings are key components in the transformer. Thermal and electrical stress, ambient conditions, and more put high demands on bushings resulting in failures originating in the bushings, most often leading to severe consequences such as fires and explosions. Condition assessment and replacement of bushings by the latest state-of-the-art technology reduce the risk of transformer failures.

On the other hand, Tap-changers cause concern due to their service needs and failure probability, but with appropriate service and certified technicians, this probability can be dramatically reduced. As the OEM of transformers and tap-changers, our global team of experts and certified technicians stand ready to provide support 24/7. Always maintain the highest quality of service with original spare parts, the latest training, and the possibility of upgrading your OLTC.

To extend the life of your assets, Hitachi Energy provides preventive (eventually curative) actions to be performed on-site, aiming to maintain the performance of the transformer for which specific equipment and a higher degree of expertise are required. It is usually linked with diagnosis tests, engineering, and life cycle assessment to clearly determine the most appropriate route of action and ensure condition-based maintenance.

Our Component Upgrades Offerings

Bushing Replacements

Hitachi Energy offers repair of high-voltage condenser bushings that includes installation, preventive maintenance, condition assessment, and replacement or upgrades.

Tap-changer Overhaul and Upgrades

Hitachi Energy offers the best resource for all tap-changer service requirements and covers services ranging from documentation, design engineering, the latest testing and oil processing, and providing 100% OEM grade parts and life extension kits.

Cooling System Overhaul and Upgrades

Hitachi Energy offers one-to-one replacements and upgrades of existing cooling solutions from original size to large size transformers.

Transformer Refurbishment

Hitachi Energy offers refurbishment services to cover transformer rehabilitation and sustainable life extension to advance a sustainable energy future for all.


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Transformer service

Aging assets, rising energy demand, and the critical need to avoid unplanned outages are challenging worldwide utilities and industrials. The service portfolio of Hitachi Energy allows utilities and industrials to maximize the return on transformer assets by ensuring high reliability, reducing life cycle costs, and ensuring optimized performance while lowering environmental impact.
Hitachi Energy Power Transformers


Hitachi Energy offers distribution and power transformers, Dry-type and EconiQ™ Transformers as well as services, for industrial and commercial applications.