Answer Posted / sriram

This calculation Applicable for 3 phase fault.

Transformer:

Step 1:
First calculate Full load current
I(F.L)=(KVA*1000)/(V*1.732)
Step 2:
Calculate multiplier factor(M)=100/%Z

Step 3:
I(sc)=I(F.L)* M

Motor

Step 4:
F=(1.732*L*I(#phase))/(c*n*E(line-ground))
step 5:
M=(1/(1+F))
step 6:

I(s.c)sym rms=I(s.c)*M
I(s.c) MOTOR=4*I(s.c)

Total fault current =Is.c(trans)+Is.c(Motor)

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