In a three-phase system, a synchronous generator supplies power to a 200-volt syn- chronous motor through a line having an impedance of 0.5/80° ohm per phase. The motor draws 5 kW at 0.8 p.f. leading and at rated voltage. The neutrals of both the generator and motor are grounded through impedances of j5 ohms. The sequence impedances of both machines are Zo = j5, Z¡ = j15, and Z2 = j10 ohms. Draw the sequence networks for this system and find the line-to-line voltage at the generator terminals. Assume balanced three-phase operation.

In a three-phase system, a synchronous generator supplies power to a 200-volt syn- chronous motor through a line having an impedance of 0.5/80° ohm per phase. The motor draws 5 kW at 0.8 p.f. leading and at rated voltage. The neutrals of both the generator and motor are grounded through impedances of j5 ohms. The sequence impedances of both machines are Zo = j5, Z¡ = j15, and Z2 = j10 ohms. Draw the sequence networks for this system and find the line-to-line voltage at the generator terminals. Assume balanced three-phase operation.

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...

See similar textbooks

Similar questions

the frequency of the induction generator on the rot ratori 9- Explain how does a synchronous generator work. Support your answer with drawing. 10-Draw the synchronous generator phasor diagram forimir tead power factor
A 350 V, 50 Hz, Y-connected, eight poles synchronous generator has the OCC given in tabular form below (Phase Voltage versus the field current). The generator has a per-phase synchronous reactance of 3.2 Q, and an armature resistance of 0.6 Q. The machine supplies a 20 KVA load, at 0.8 PF lagging. How much field current must be supplied to the generator to keep the terminal voltage at 350 V? EA. (V) 65 125 260 290 320 350 380 420 450 470 IF, (A) 0.00 0.5 1.0 2.0 2.25 2.55 2.7 3.0 3.7 4.1 4.25 Select one: O a. If = 2.7 A O b. IF = 2.25 A O c. None O d. Ip = 2.55 A Clear my choice
9. An 11-kV, three-phase wye-connected generator has a synchronous impedance of 6-ohms per phase and negligible armature resistance. For a given field current, the open circuit voltage is 12kV. Calculate the armature current for the maximum power condition. Ans: 1566.4 A
Differentiate the leading and lagging of the generating system?
88
a. 4 KA O b. None of these O c. 6.25 kA O d. 2.309 KA A 100-MVA, 60-kV, three-phase synchronous generator has a synchronous reactance of 16 Ohms/phase and negligible armature resistance. The generator is operating with an excitation per phase E= 47.116 KV, and is delivering maximum power before losing synchronism (stability limit). Thus, the maximum generated power is Pmax = and the armature current is la = 306 MW None of these 102 MW 530 MW A 90-MVA 69.3-kV, three-phase synchronous generator has a synchronous reactance of 10 Ohms/phase and negligible armature resistance. The generator is delivering power to the bus bar at the rated voltage with its field current adjusted for a generated emf (excitation voltage) of 50 kV per phase and a power angle & = 7.1 degree. Thus, the delivered power is the generator armature current is and the power factor is The thre tings of the below.electr nower system is given below:
3-phase 9kVA power 60 Hz 208 Volt 8-pole synchronous generator winding resistance is negligible, synchronous reactance is j8 ohms per phase. The generator was first connected in parallel with a 3-phase 60 Hz, 208 V generator. Calculation of induced voltage per phase for cosφ = 0.8 inductive. Determine the power angle. Draw the phasor diagram.
a syn A: A sylienfonotus generator of 100 MVA, 22 kV, and 0.25 pu transient reactance supplies a motor of 50 MVA, 22 kV, and 0.2 pu transient reactance. The motor is drawing 40 MW at 0.8 power factor leading and terminal voltage of 21.9 kV. The line connecting them has a reactance of 0.05 pu on a base of 100 MVA. Find the transient currents in the generator, the motor, and the fault when a 3-ph fault occurs at the motor terminals. Take SB = 100 MVA, VB = 22 kV, and use the internal voltages %3D %3D of the machines method.
A 10 KVA, 400 V, 3 phase, star cónnected synchronous generator has an armature resistance of 0.80 per phase and synchronous reactance of 1.5 Q per phase. The voltage regulation at a power factor 0.6 lagging is
A generator is connected through a transformer to a synchronous motor as shown in the following figure. (All values in this problem are per unit.) Before the fault V,=0.9,1=1 with power factor 0.8 lagging. jX, P + jX ds jX" dm + E. E The reactances are Xd=0.15 , X,=0.1 , X âm=0.35. A symmetric fault occurs at P. Find the per-unit current magnitudes in the fault, the generator and the motor (a) using subtransient voltages. (b) using a Thevenin equivalent.
Three identical steam-turbine generators G1, G2, and G3 are operating in parallel. Each generator is: 7.2 KV, 25.4 MVA, 60 Hz, 0.77 PF lagging, 4-poles, Y-connected, with synchronous reactance of 2 Q and an armature resistance of 0.05 Q. Each of generators G¡ , and G2 has a characteristic power-frequency slope of 5.8 MW/Hz, and no-load frequency of 62.5 Hz. Generator G3 has a characteristic power-frequency slope of 6.0 MW/Hz. Find the no-load frequency of generator G3 for which all generators supply a load of 38.5 MW, at fsys = 60 Hz. Select one: O a. fsys = 62.5 Hz O b. fsys = 61.85 Hz O c. None O d. fsys = 61.58 Hz Clear my choice