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GATE 2023 Power Systems Quiz 49

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Question 1

In a 3- transmission line voltage drop across each line is given by the following equation :

If the line has zero sequence reactance of and positive sequence reactance of then the values of and will be.

Question 2

Two, 11 kV, 30 MVA 3–ϕ star connected generators operates in parallel. The positive, negative and zero sequence reactance of each being respectively, j0.16, j0.14, j0.08 p.u. The star point of one of the generators is isolated and that of the other is solidly grounded. Find the fault current for a fault impedance of j0.08Ω for line to line fault on terminals of generators?

Question 3

Consider a system-

PU reactance network in steady state will look as-

Question 4

The positive, negative and zero sequence reactances of an alternator are j0.3, j0.25 and j0.1 and its star point is grounded through an impedance of j0.If a LLG fault occurs on the terminals of the alternator through a fault impedance of Zf=j0.1p4, than the fault current is _____ pu (upto two decimal) (Assume pre fault voltage =1 pu)

Question 5

A synchronous generator rated 100 kVA, 400 V, 0.1 pu. Sub transient reactance is supplying a possive load of 350 kW at 0.8 lagging power factor. If a 3- phase fault occurs at the generator terminal, then the magnitude of initial symmetrical fault current is _____________.

Question 6

A 3 phase 10 MVA, 11 kV generator with neutral solidly grounded supplies a feeder the positive negative and zero sequence impedance of generator and feeder are j1.2 , j0.9 , j0.4 Ω and j1Ω, j1 Ω, j3 Ω respectively. A fault from one phase to ground occurs at far end of the feeder. Find the voltage to neutral of the faulty phase at terminal of generator (in KV)?
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