SilverArc
Electrical
- Sep 20, 2006
- 82
Hi Jghrist,
I could not find my answer so as per your suggestion, I am starting this new thread:
If I have a 10 MVA transformer with 7 % impedance at 69/13.8 KV...
The short circuit level at secondary is 5981 A and primary is 1196.2 A. When I know this is the possible primary short circuit in primary as well as seconday, then why do I need the short circuit MVA from Utility.
As you advised to have the utility impedance, Utility is an infinite source: I guess the main applications of the SC MVA is to decide the rating of the Primay protective device like a circuit switcher or a breaker and has nothing to do with the secondary rating:
But technically, if my primary short circuit utility short circuit is 40000A then secondary short circuit as per my trasnformer configuration should be 40000x(13800/69000)=8000 A, which is not possible as the transformer can only deliver 5981 A.
Do u think, if I am making sense ?
Thanks
I could not find my answer so as per your suggestion, I am starting this new thread:
If I have a 10 MVA transformer with 7 % impedance at 69/13.8 KV...
The short circuit level at secondary is 5981 A and primary is 1196.2 A. When I know this is the possible primary short circuit in primary as well as seconday, then why do I need the short circuit MVA from Utility.
As you advised to have the utility impedance, Utility is an infinite source: I guess the main applications of the SC MVA is to decide the rating of the Primay protective device like a circuit switcher or a breaker and has nothing to do with the secondary rating:
But technically, if my primary short circuit utility short circuit is 40000A then secondary short circuit as per my trasnformer configuration should be 40000x(13800/69000)=8000 A, which is not possible as the transformer can only deliver 5981 A.
Do u think, if I am making sense ?
Thanks