Modeling SC Current on Substation Transformer Secondary
Modeling SC Current on Substation Transformer Secondary
(OP)
We know the Utility Available Fault Current on the 115 kV Substation Side (@100 MVA base), also, source impedances are known as well as the Substation Transformer Z% (%8).
How do I Calculate the Fault Current on 13.2kV Secondary Side of the Substation Transformer (115/13.2, 21 MVA, %Z=8)
Thanks in advance for your help and time
How do I Calculate the Fault Current on 13.2kV Secondary Side of the Substation Transformer (115/13.2, 21 MVA, %Z=8)
Thanks in advance for your help and time






RE: Modeling SC Current on Substation Transformer Secondary
Read up the text books or IEEE "Buff" or "Red" Book.
RE: Modeling SC Current on Substation Transformer Secondary
Bung
Life is non-linear...
RE: Modeling SC Current on Substation Transformer Secondary
1. Convert the transformer Z to 100MVA and 115V bases.
Z115kV,pu=Z13.2kV,pu x (100MVA/21MVA) x (13.2kV/115kV)^2
2. Calculate the short circuit current on the transformer primary side Ip,pu:
Ip,pu=1.0pu/(Zsys,pu+Z115kV,pu)
3. Transfer the short circuit current Ip,pu to the secondary side
Is,pu=Ip,pu x 115kV/13.2kV
4. Express the Ip,pu in Ip,amps
Is,amps=Is,pu x Is,base
where
Is,base=21000kVA/(sqrt3 x 13.2kV)=919A
RE: Modeling SC Current on Substation Transformer Secondary
Not on my monitor screen, they aren't!! Guilty until proven innocent - and this question just can't be from a practising engineer working on substation design because it is such a basic question.
Buy a book and study it like we had to!
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Start each new day with a smile.
Get it over with.
RE: Modeling SC Current on Substation Transformer Secondary
There was no need for the harsh words!! anyway, thanks all.
RE: Modeling SC Current on Substation Transformer Secondary
RE: Modeling SC Current on Substation Transformer Secondary
Get professional help (engineering that is).
_______________________________________
Colin J Flatters BSc(Hons) IEng MIEE MIIE
Electrical Engineer / Project Manager
Email - cflatters@colin7.demon.co.uk.