A 1200 kVA, 3.3-kV, three-phase, star-connected alternator has an effective resistance that is 1.5 times the dc resistance. The dc resistance is obtained by connecting two terminals to a dc source. The current and voltage are 87.6 A. and 6V, respectively. A field current of 30 A produces a current of 200 A on short-circuit and 1.1 kV on open circuit. a. Calculate the power angle and the total generated complex power when the generator is operating full-load of 1200 kVA at 0.9 pf lagging and at rated terminal voltage. Assume that flux varies as the field current. b. If the altenator is operating at the same excitation voltage as in (a), calculate the maximum kW output of the alternator.

A 1200 kVA, 3.3-kV, three-phase, star-connected alternator has an effective resistance that is 1.5 times the dc resistance. The dc resistance is obtained by connecting two terminals to a dc source. The current and voltage are 87.6 A. and 6V, respectively. A field current of 30 A produces a current of 200 A on short-circuit and 1.1 kV on open circuit. a. Calculate the power angle and the total generated complex power when the generator is operating full-load of 1200 kVA at 0.9 pf lagging and at rated terminal voltage. Assume that flux varies as the field current. b. If the altenator is operating at the same excitation voltage as in (a), calculate the maximum kW output of the alternator.

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

Chapter2: Fundamentals

Section: Chapter Questions

Problem 2.21P: An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor...

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An industrial plant consisting primarily of induction motor loads absorbs 500 kW at 0.6 power factor lagging. (a) Compute the required kVA rating of a shunt capacitor to improve the power factor to 0.9 lagging. (b) Calculate the resulting power factor if a synchronous motor rated at 500 hp with 90 efficiency operating at rated load and at unity power factor is added to the plant instead of the capacitor. Assume constant voltage (1hp=0.746kW).
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