how we have to calculate the short circuit current for
33/11kv 2mva, 7.5% Z, Transformer primary side breaker and
secondary side breaker short circuit current for both sides?.

Answer Posted / madhu

Fault impedance in secondary Z = %Z x 10 x (KV)²/KVA
= 7.5*10*11*11/2000
= 4.5 OHMS
then fault current in sec = V/(Z*1.732)
= 11000/(4.5*1.732)
= 1411 A or 1.4kA
similarly in primary Z = 7.5*10*33*33/2000
= 40.83
then fault current in prim = 33000/(40.53*1.732)

= 0.466kA

Is This Answer Correct ?    0 Yes 3 No



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