Power Transformers

[blacklabs]

How does one calculate the Emergency Rating (MVA) of a power transformer?

 

[rbulsara]

Ask mfrs!! It also depends on duration of 'emergency' and load during "emergency". Bottom line is not to exceed temperature limit. There is no standard formula that I know of.

There have been instances of people trying to keep the transformer cool with garden hoses to keep the service going!!

 

[jghrist]

C57.91, IEEE Guide for Loading Mineral-Oil-Immersed Transformers

 

[blacklabs]

I'm not an electrical engineer, but some one who has been given the task of finding this data based upon what appears on the name plate. Thanks anyway!

 

[rbulsara]

so what appears on the nameplate?

 

[dpc]

What is the size/type of the transformer (oil-filled? kVA?)



"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[prc]

Please look table 4 of IEC 60076-7 of 2005-12.Over Loading guide .It lists permissible emergency ratings for different type of trfs ( Distribution,medium and large) for different loading conditions viz Normal cyclic overloading, long time emergency loading,short time emergency loading.

 

[blacklabs]

160000/213000/266000
OA FA FA

 

[rbulsara]

and what is the normal load and what would be the "emergency load"?

You already have three ratings or mode of cooling.