Substation Rated Capacity

[22574]

If the transformer of a substation had a capacity
of 60MVA/80MVA/100MVA;
OA/FA1/FA2.

Can I say that it is a 100MVA S/S?

Could anyone can explain to me if this right or not?

Your reply is highly appreciated.

 

[jmmee97]

22574
It depends. The transformer is designed to operate at 100MVA without its life expectancy being shortened. Other factors to consider are the ratings of your main bus and equipment. Is the main bus, both HV and LV rated for the current expected at 100MVA? Switches? etc...

 

[dpc]

If the nameplate says 100 MVA, then you have 100 MVA capacity, provided that the cooling equipment is still there and functional.

You have to be a little careful if you are just looking at a one-line, however. Sometimes transformers are purchased with "provisions" for future cooling, but without the actual fans. The one-lines often will show the full blown rating of the xfmr, even though the fans were never added.

 

[cuky2000]

The 100 MVA rating is based on 30oC ambient temperature, long-term operation and up to 3000 ft above sea level. For other environmental conditions, this rating needs to be adjusted above or below as shown in the curve enclose

http://cuky2000.250free.com/Tr_Load.jpg

Please note that there may be allowance to overload the transformer and other system components beyond the nameplate/rating for short term.

 

[nightfox1925]

In my own opinion, if the primary and secondary conductors and the associated secondary switchgear is rated to carry the transformer forced cooled rating then it is proper for you to define the substation rating based on the FA rating regardless whether you are using that rating for long periods or not.

It is more convenient to define the substation based from the installed capacity rather than the actual operating capacity. If there are other ways to define such installation, please let me know since this is my opinion.

GO PLACIDLY, AMIDST THE NOISE AND HASTE-Desiderata