Eo(LL) (V)a)3000b)25002000150010005000No-load excitation curve @3600rpm0 123 4 5 6DC Excitation current (A)7The figure above shows the no-load excitation (LL) curve of a 3-ph, 2-pole, 60 Hz, 1000 kVA,2.3 kV synchronous alternator at rated speed. The alternator has negligible resistance andSynchronous Reactance Xs = 1.2 n/phase.If the alternator is synchronized to the Power Grid at 2.3 kV (Line to Line), calculate thefollowing:8 9 10The value of excitation current required for full load current at 0.7 pf lagging(over-excited).|EO(LL)IIFThe alternator current and reactive power when it is delivering 80% rated power(0.8 MW) and its DC excitation current is 4 A.ILQ3ph

Synchronous generator converts mechanical energy to electrical energy. The OCC curve is drawn…

a) b) The value of excitation current required for full load current at 0.7 pf lagging (over-excited). |EO(LL)I IF The alternator current and reactive power when it is delivering 80% rated power (0.8 MW) and its DC excitation current is 4 A. IL Q3ph

a) b) The value of excitation current required for full load current at 0.7 pf lagging (over-excited). |EO(LL)I IF The alternator current and reactive power when it is delivering 80% rated power (0.8 MW) and its DC excitation current is 4 A. IL Q3ph

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.3MCQ: The amplitude of the sinusoidal symmetrical ac component of the three-phase short-circuit current of...

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Concept explainers

Synchronous Motor

The synchronous motor is an AC electric type motor where at a steady-state the shaft rotation is synchronized with the supply current variable-frequency. To an integral number of AC cycles, the rotation period is exactly equal. The stator of the motor in the synchronous motor contains multi-phase AC electromagnets due to which a magnetic field is created that rotates in time with the oscillation of the line current. The rotor contains a permanent magnet and the rotor rotates in synchronization with the stator field at the same rate and provides the second synchronized magnetic field which is rotating in nature as a result. When the synchronous motor is supplied with independently excited multi-phase AC electromagnets on both the rotor and the stator, it is termed as a doubly-fed machine. The most widely used AC-type motors are the synchronous AC motor and the induction AC motors.

Question

100%

Eo(LL) (V)
a)
3000
b)
2500
2000
1500
1000
500
0
No-load excitation curve @3600rpm
0 1
2
3 4 5 6
DC Excitation current (A)
7
The figure above shows the no-load excitation (LL) curve of a 3-ph, 2-pole, 60 Hz, 1000 kVA,
2.3 kV synchronous alternator at rated speed. The alternator has negligible resistance and
Synchronous Reactance Xs = 1.2 n/phase.
If the alternator is synchronized to the Power Grid at 2.3 kV (Line to Line), calculate the
following:
8 9 10
The value of excitation current required for full load current at 0.7 pf lagging
(over-excited).
|EO(LL)I
IF
The alternator current and reactive power when it is delivering 80% rated power
(0.8 MW) and its DC excitation current is 4 A.
IL
Q3ph

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