Question { Alstom, 21903 }
I HAVE A 1 MVA TRANSFORMER, I WANT TO KNOW THE FAULT LEVEL OF
THE SYSTEM ( WHAT IS FAULT LEVEL PLEASE EXPLAIN WITH EXAMPLE)
Answer
1 MVA, 11/0.415kV Transformer
Full load current= 1000000/(1.732x415) = 1391.24A
% Z(Impedance)=5 (As per IS 2026 for transformer ratings of
0.631 MVA to 1.24 MVA)
Fault current= IFL/%Z =1391.24/0.05 =27.824 kA