Question 3: (2+6+6+3+3=20 Marks) "approximtly 25 min" VS A 13.8-kV, 50-MVA, 60-Hz, four-pole, Y-connected synchronous ge

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Question 3 2 6 6 3 3 20 Marks Approximtly 25 Min Vs A 13 8 Kv 50 Mva 60 Hz Four Pole Y Connected Synchronous Ge 1 (67.67 KiB) Viewed 14 times

Question 3: (2+6+6+3+3=20 Marks) "approximtly 25 min" VS A 13.8-kV, 50-MVA, 60-Hz, four-pole, Y-connected synchronous generator has a synchronous reactance of 2.5 02/phase, and a negligible armature resistance. At 60 Hz, its friction and windage losses are 1 MW, and its core losses are 1.5 MW. The field circuit has a dc voltage of 120 V and the filed current can be varied from 0 to 10 A. The Open-Circuit Curve (OCC) of this generator is shown in the figure below. a) How much field current is required to make the line terminal voltage equal to 13.8kV at no load? b) What will be the generated emf phasor (magnitude and angle) when the generator delivers angle 80% load at 0.8 PF lagging and rated terminal voltage? c) If the load PF remains constant, but its magnitude Increases resulting in torque (power) angle increase of 5 degrees (added to the value found in part b) above), find the generator's new-armature current and induced emf magnitude. d) If the load in part b) is suddenly removed, what will be the terminal voltage? e) Draw the vector/phasor diagram of the two loading cases and d) (draw one diagram for the two loading cases and show all magnitudes and angles) Open-ciscoit characteristic 20 18 = c 16 14 4 5 6 Field current (A) Open-circuit voltage (KV) 2 7 9 10