Question

If the percentage reactance of the system up to the fault point is 30% and the base kVA is 9,000. Find the value of the short circuit kVA
1. 50,000
2. 45,000
3. 30,000
4. 33,000

Answer 1

Correct Answer - Option 3 : 30,000

Concept:

Short circuit MVA or Fault MVA = (Base MVA) x 100 / (% X)

Where,

X = Thevenin equivalent reactance between fault point and zero power bus (ZPB)

Calculation:

Given that, Base kVA = 9000

Reactance (X­_eq) = 30% = 0.3

Short circuit kVA = 9000/0.3 = 30,000 kVA