A 3-phase generating station has two 15000 kVA generators connected in parallel each with 15% reactance. A symmetrical fault occurs at the generator bus. What will be the short circuit in MVA?
Calculate the equivalent impedance of the two generators in parallel:
Zeq = (X1 * X2)/(X1 + X2)
= (0.15 * 0.15) / (0.15 + 0.15)
= 0.075 per unit
Convert the base kVA to MVA:
Base MVA = 15,000 kVA / 1000
= 15 MVA
Calculate the short circuit MVA:
Short circuit MVA = Base MVA / Zeq
= 15 MVA / 0.075
= 200 MVA
Therefore, the short circuit MVA at the generator bus during a symmetrical fault is 200 MVA.