Answer:
a) 208.33 A
b) 1.152 Ω
c) 0.03456 Ω
d) 6943.64 A
Step-by-step explanation:
Transformer ratings :
Base power ( Sb ) = 50 KVA ,
Transformer voltage = 2400 / 240 V ,
Impedance ( Zp.u ) = 3.0 % = 0.03
phase = single ( 1 ) phase
Base Voltage on low side ( Vb ) = 240 V
a) Calculate the base current ( Ib )
Ib = Sb / Vb = ( 50 * 10^3 ) / 240
= 208.33 A
b) calculate base impedance ( Zb )
Zb = Vb^2 / Sb = ( 240 )^2 / 50000
= 1.152 Ω
c) Calculate the actual impedance ( Zact )
Zact = Zp.u * Zbase
= 0.03 * 1.152 = 0.03456 Ω
d) Calculate the short circuit current ( Isc )
Isc = Vp.u / Zp.u
= 1 / 0.03 = 33.33 p.u
therefore Isc = 33.33 * Ib
= 33.33 * 208.33 = 6943.64 A