How Does Altitude Affect a Transformer?
Quick answer — At high altitude the air is thinner, so its dielectric strength and cooling are reduced. This means the insulation clearance and creepage may need to be increased, and the transformer may need to be derated (or its cooling increased) because the air cooling and the dielectric are less effective. Standards give a derating and clearance correction, and the design must account for the site altitude.
How does high altitude affect a transformer?
Dielectric effect
Thinner air has a lower dielectric strength, so the insulation clearance and creepage often need a correction at altitude, and the BIL/impulse margin must be checked.
Cooling effect
Air cooling is less effective at altitude, so for air-cooled units the rating may need derating or the cooling increased.
How to handle it
Specify the site altitude, apply the standard correction (e.g. for clearance and derating), and design (or derate) the unit for the altitude so it performs correctly.
References & standards
- IEC 60076-1
- IEEE C57.12.00 (altitude correction)
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
Related components
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.
Source transformers for this application
Submit an RFQ or browse manufacturers and components.
Submit an RFQ Get Verified