What are the temperature rise limits for different insulation classes of dry type transformers?

The temperature rise of each winding of the transformer, designed for operation under normal service conditions, shall not exceed the corresponding limit specified in following table when tested in accordance IEC 60076-11.
The maximum temperature occurring in any part of the winding insulation system is called the hot-spot temperature.
The hot spot temperature shall not exceed the rated value of the hot-spot winding temperature specified in IEC 60076-11.


Note: When the transformer is installed inside a prefabricated substation the IEC 62271-202 standard is applicable, and the temperature rise class of the enclosure is defined,
introducing requirements on the temperature behavior of the substation (checked through a dedicated temperature rise test).

Released for:Schneider Electric South Africa