CT Sizing of Differential CT's in Transformer

I'll be pleased to replay the standard answer.

Please do your own homework!

I'll not elabrote any further.

as this is your first post, I would suggest you search through CR4 with the keywords "CT ratio" and study the answers.

You obviously know how to use a computer and maybe a search engine, (is that how you found CR4?), so do a little bit more work and study the replies of which there are many on the subject.. and if that is to difficult, search MY replies and you will find an answer from me on the subject.

Happy researching!

ps.. what is "Trafo"??

trafo short form of transformer..

i have calculated ratios as well as rated current too on both primary and secondary side.

and i have seen your few post as well. please guide me to your specific post that you are mentioning.

thank you for enlightening me on your shorthand, however i would suggest that as English is not your first language, you refrain from trying out experiments in shortening english and spell words correctly.. It makes it so much easier to understand you.

AS for my posts, then if you have read them you have got your answers, use the formula contained therein.

What do you mean by 115/57.5/57.5MVA? Going by this I understand that this transformer must be a three-winding transformer (one 11.5kV winding and two 220kV windings) and not a two-winding trafo as mentioned by you. Pl. confirm this.

And... What is the vector connection of this transformer?

Waht are the connected sources at the primary and at each of the secondary? are they earthed or not? If earthed, how? Solid or resistance or reactance? What is the source impedance, what are the other network impedances, what is the trafo impedance?

Unless all the above data are given, it is very difficult to size a differential CT precisely.

What is Winding Configuration / Vector Group ?