I came up with an SCA of 83,619.64 Amps at the Transformer (3Ø Bolted Fault, Infinite Primary, 0.9 of the %Z for tolerances).
Here's the formula I used to acheive the resulting 83619.64 amps:
1: Determine the Full-Load Amperes of the Transformer:
I(FLA) = KVA × 1000 ÷ E(L-L) × 1.73
[ "I(FLA)" = Full-Load Amperes, "E(L-L)" = Line-To-Line Voltage ]
2: Find Transformer's Multiplier:
Mpl. = 100 ÷ 0.9 × %Z
[ "Mpl." = Multiplier, "0.9" figures worst-case scenario tolerance of Impedance percentage ]
3: Determine Transformer's Let-Through Current:
I(SCA) = I(FLA) × Mpl.
So using your Transformer's ratings, here's what it looks like:
1: I(FLA) = 1204.2 Amps
( 1000 × 1000 ÷ 480 × 1.73 )
2: Mpl. = 69.44
( 100 ÷ 0.9 × 1.6 )
3: I(SCA) = 83619.644444- Amperes
( 1204.2 × 69.44 )
Check my math and let me know if there are any errors.
Scott35 S.E.T.