I am working through the Complex Imaginary exams which is a trip by itself but I ran across a formula that I wanted someone to back check if possible.
Problem #53 Variation 4: A customer of a utility is asking for an additional service for a three-phase transformer. The utility says the short circuit current available at the building site is 7125A at 22kV. What is the source impedance for the 2500kVA, 22/6.6kV transformer with an impedance of 4.25%?
CI Solution:
kVAsc = Isc * V * sqrt(3) = 271.500MVA
%Zs = kVAt/kVAs * 100 = 2500/271500*100 = 0.92%
The last formula for %Zs is the one I can not verify. Any help would be greatly appreciated.
Problem #53 Variation 4: A customer of a utility is asking for an additional service for a three-phase transformer. The utility says the short circuit current available at the building site is 7125A at 22kV. What is the source impedance for the 2500kVA, 22/6.6kV transformer with an impedance of 4.25%?
CI Solution:
kVAsc = Isc * V * sqrt(3) = 271.500MVA
%Zs = kVAt/kVAs * 100 = 2500/271500*100 = 0.92%
The last formula for %Zs is the one I can not verify. Any help would be greatly appreciated.
