How Do You Increase the Capacity of a Transformer?
Quick answer — You cannot easily raise the nameplate rating of an existing transformer, but you can increase the available capacity by upgrading the cooling (ONAN to ONAF/OFAF, if the design allows and the impedance/insulation permit), or by improving the load management. A true capacity increase usually means a new or larger transformer, or replacing a smaller unit in a substation with a larger one.
Can you increase the capacity of a transformer?
Cooling upgrade
Adding fans or pumps (ONAN to ONAF/OFAF) can raise the rating if the design, insulation class and impedance allow, subject to the manufacturer and the temperature limits.
Load management
Better load monitoring, phase balancing and using a spare can increase the usable capacity without changing the transformer.
A larger unit
For a real capacity gain, install a larger transformer or add a parallel unit, subject to the substation space, protection and the fault level.
References & standards
- IEC 60076-7
- IEEE C57.91
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
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Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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