Question 1 A 125 MVA, 20 kV, three-phase, wye-connected, 60 Hz, synchronous alternator is connected to a 20 kV power grid. The alternator has negligible armature resistance and synchronous reactance of 5 2/phase. The mechanical limit of the turbine powering the alternator limits its maximum power output to 100MW. (a) Calculate the value of excitation voltage (line to neutral with angle) needed for 50% maximum power (50MW) at unity pf. |E(LN) 8 (b) Find the alternator reactive power import/export if its real power output is now increased to 75% rated (75 MW) with the excitation unchanged. (1) Draw before and after phasor diagrams on the same axes (performance chart) to illustrate the two operational states. (ii) Calculate the alternator reactive power import/export when its real power output is increased to 75% rated (75 MW) with the excitation unchanged. Q3ph Import or export?

Question 1 A 125 MVA, 20 kV, three-phase, wye-connected, 60 Hz, synchronous alternator is connected to a 20 kV power grid. The alternator has negligible armature resistance and synchronous reactance of 5 2/phase. The mechanical limit of the turbine powering the alternator limits its maximum power output to 100MW. (a) Calculate the value of excitation voltage (line to neutral with angle) needed for 50% maximum power (50MW) at unity pf. |E(LN) 8 (b) Find the alternator reactive power import/export if its real power output is now increased to 75% rated (75 MW) with the excitation unchanged. (1) Draw before and after phasor diagrams on the same axes (performance chart) to illustrate the two operational states. (ii) Calculate the alternator reactive power import/export when its real power output is increased to 75% rated (75 MW) with the excitation unchanged. Q3ph Import or export?

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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