2. A 3-phase, 75 MVA, 11-8 kV star-connected alternator with a solidly earthed neutral point has the fol- lowing p.u. impedances based on rated phase voltage and rated phase current : Positive phase...

Extracted text: 2. A 3-phase, 75 MVA, 11-8 kV star-connected alternator with a solidly earthed neutral point has the fol- lowing p.u. impedances based on rated phase voltage and rated phase current : Positive phase sequence impedance j2 p.u. j0-16 p.u. j0-08 p.u. Negative phase sequence impedance Zero phase sequence impedance Determine the steady-state fault current for the following : (i) 3-phase symmetrical short-circuit (ii) one line-to-earth fault (iii) two line-to-earth fault. The generated e.m.f. per phase is equal to the rated voltage. [(i)1840 A (ii) 4920 A (iii) 3580 A] 3. The per unit values of positive, negative and zero sequence reactances of a network at fault are 0-08, 0-07 and 0-05 respectively. Determine the fault current if fault is line-to-line-to-ground. j 16 p.u.]