Can transformers be operated above a 1000m/3300′ altitude?
There are two main considerations for operating transformers at altitudes above 1000m/3300′. Current standards state designs must be valid to these heights. Above this height, the density of air no longer works as effectively to remove heat. As a result the functional kVA of the transformer must be reduced at higher altitudes, typically about .3% for every 100m/330′. The second issue is the dielectric constant of air is reduced at higher altitudes. Dry type transformers use air gaps as an important component of the electrical insulation properties. At higher altitudes, this lower insulation values, typically in medium voltage BIL levels. Ideally, if transformers will be installed above 1000m, inform the manufacturer and the design can be adjusted to meet all requirements at the higher altitudes.