Power System Analysis and Design (MindTap Course List)
6th Edition
ISBN: 9781305632134
Author: J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma
Publisher: Cengage Learning
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Textbook Question
Chapter 2, Problem 2.22MCQ
In a balanced three-phase Y-connected system with a positive-sequence source, the line-to-line voltages are
(a) True
(b) False
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Students have asked these similar questions
In a balanced system, the phasor sum of the line-to-line voltages and the phasor sum of the line-to-neutral voltages are always equal to zero.(a) False (b) True
2.21
The three-phase source line-to-neutral voltages are given by
E = 10/0°, Em = 10/+240°, and En = 10/-240 volts.
Is the source balanced?
(a) Yes
(b) No
In a balanced 3-phase wye-connected system with positive-sequence source, the line-
to-line voltages are v3 times the line-to-neutral voltages and lend by 30.
(a) True
2.22
(b) False
2.23 In a balanced system, the phasor sum of line-to-line voltages and the phasor sum of
line-to-neutral voltages are always equal to zero.
(a) False
(b) True
2.24 Consider a three-phase Yconnected source feeding a balanced-Y load. The phasor
sum of the line currents as well as the neutral current are always zero.
(b) False
(a) True
2.25
For a balanced-A load supplied by a balanced positive-sequence source, the line cur-
rents into the load are v3 times the A-load currents and lag by 30°.
(a) True
A balanced A-load can be converted to an equivalent balanced-Y load by dividing the
A-load impedance by
(a) V3
When working with balanced three-phase circuits,…
In Figure 1, the 3-phase source has a line-to-line voltage of 440 volts. The
details of the impedances are the following: Z₁ = 36-j15; Z₂ = 40 +
/300; Z₂ = 45+j60 ; Z₂ = 75 + jo ; Z5 = 50+j50; Z6 = 20+ j48 2.
Determine the following:
(a) Line currents: labi, and I
(c) Line currents: lar, Ibr, and ICT;
(b) Line currents: Iaz, Ibz, and Iczi
(d) PT, QT, ST, and pft for the system;
(e) W, and W, readings for 2-wattmeter method at lines a and b.
Balanced
3-Phase
ab-bc-ca
source
C
Figure 1
→laT
-Ibr
-KT
1
lal
²3
↓
Ibi
1
Ici
la2
lb2
le2ܝ
150
1²₂
OND
Chapter 2 Solutions
Power System Analysis and Design (MindTap Course List)
Ch. 2 - The rms value of v(t)=Vmaxcos(t+) is given by a....Ch. 2 - If the rms phasor of a voltage is given by V=12060...Ch. 2 - If a phasor representation of a current is given...Ch. 2 - Prob. 2.4MCQCh. 2 - Prob. 2.5MCQCh. 2 - Prob. 2.6MCQCh. 2 - Prob. 2.7MCQCh. 2 - Prob. 2.8MCQCh. 2 - Prob. 2.9MCQCh. 2 - The average value of a double-frequency sinusoid,...
Ch. 2 - The power factor for an inductive circuit (R-L...Ch. 2 - The power factor for a capacitive circuit (R-C...Ch. 2 - Prob. 2.13MCQCh. 2 - The instantaneous power absorbed by the load in a...Ch. 2 - Prob. 2.15MCQCh. 2 - With generator conyention, where the current...Ch. 2 - Consider the load convention that is used for the...Ch. 2 - Prob. 2.18MCQCh. 2 - The admittance of the impedance j12 is given by...Ch. 2 - Consider Figure 2.9 of the text, Let the nodal...Ch. 2 - The three-phase source line-to-neutral voltages...Ch. 2 - In a balanced three-phase Y-connected system with...Ch. 2 - In a balanced system, the phasor sum of the...Ch. 2 - Consider a three-phase Y-connected source feeding...Ch. 2 - For a balanced- load supplied by a balanced...Ch. 2 - A balanced -load can be converted to an...Ch. 2 - When working with balanced three-phase circuits,...Ch. 2 - The total instantaneous power delivered by a...Ch. 2 - The total instantaneous power absorbed by a...Ch. 2 - Under balanced operating conditions, consider the...Ch. 2 - One advantage of balanced three-phase systems over...Ch. 2 - While the instantaneous electric power delivered...Ch. 2 - Given the complex numbers A1=630 and A2=4+j5, (a)...Ch. 2 - Convert the following instantaneous currents to...Ch. 2 - The instantaneous voltage across a circuit element...Ch. 2 - For the single-phase circuit shown in Figure...Ch. 2 - A 60Hz, single-phase source with V=27730 volts is...Ch. 2 - (a) Transform v(t)=75cos(377t15) to phasor form....Ch. 2 - Let a 100V sinusoidal source be connected to a...Ch. 2 - Consider the circuit shown in Figure 2.23 in time...Ch. 2 - For the circuit shown in Figure 2.24, compute the...Ch. 2 - For the circuit element of Problem 2.3, calculate...Ch. 2 - Prob. 2.11PCh. 2 - The voltage v(t)=359.3cos(t)volts is applied to a...Ch. 2 - Prob. 2.13PCh. 2 - A single-phase source is applied to a...Ch. 2 - Let a voltage source v(t)=4cos(t+60) be connected...Ch. 2 - A single-phase, 120V(rms),60Hz source supplies...Ch. 2 - Consider a load impedance of Z=jwL connected to a...Ch. 2 - Let a series RLC network be connected to a source...Ch. 2 - Consider a single-phase load with an applied...Ch. 2 - A circuit consists of two impedances, Z1=2030 and...Ch. 2 - An industrial plant consisting primarily of...Ch. 2 - The real power delivered by a source to two...Ch. 2 - A single-phase source has a terminal voltage...Ch. 2 - A source supplies power to the following three...Ch. 2 - Consider the series RLC circuit of Problem 2.7 and...Ch. 2 - A small manufacturing plant is located 2 km down a...Ch. 2 - An industrial load consisting of a bank of...Ch. 2 - Three loads are connected in parallel across a...Ch. 2 - Prob. 2.29PCh. 2 - Figure 2.26 shows three loads connected in...Ch. 2 - Consider two interconnected voltage sources...Ch. 2 - Prob. 2.35PCh. 2 - Prob. 2.36PCh. 2 - Prob. 2.37PCh. 2 - Prob. 2.38PCh. 2 - Prob. 2.39PCh. 2 - A balanced three-phase 240-V source supplies a...Ch. 2 - Prob. 2.41PCh. 2 - A balanced -connected impedance load with (12+j9)...Ch. 2 - A three-phase line, which has an impedance of...Ch. 2 - Two balanced three-phase loads that are connected...Ch. 2 - Two balanced Y-connected loads, one drawing 10 kW...Ch. 2 - Three identical impedances Z=3030 are connected in...Ch. 2 - Two three-phase generators supply a three-phase...Ch. 2 - Prob. 2.48PCh. 2 - Figure 2.33 gives the general -Y transformation....Ch. 2 - Consider the balanced three-phase system shown in...Ch. 2 - A three-phase line with an impedance of...Ch. 2 - A balanced three-phase load is connected to a...Ch. 2 - What is a microgrid?Ch. 2 - What are the benefits of microgrids?Ch. 2 - Prob. CCSQCh. 2 - Prob. DCSQ
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- A balanced three-phase load is connected to a 4.16-kV, three-phase, fourwire, grounded-wye dedicated distribution feeder. The load can be mode led by an impedance of ZL=(4.7+j9)/phase, wye-connected. The impedance of the phase conductors is (0.3+j1). Determine the following by using the phase A to neutral voltage as a reference and assume positive phase sequence: (a) Line currents for phases A, B, and C. (b) Line-to-neutral voltages for all three phases at the load. (c) Apparent. active, and reactive power dissipated per phase, and for all three phases in the load. (d) Active power losses per phase and for all three phases in the phase conductors.arrow_forwardThe three-phase source line-to-neutral voltages are given by Ean=100,Ebh=10+240, and Ecn=10240volts. Is the source balanced? (a) Yes (b) Noarrow_forwardA Y-connected load bank with a three-phase rating of 500 kVA and 2300 V consists of three identical resistors of 10.58. The load bank has the following applied voltages: Vab=184082.8,Vbc=276041.4, and Vca=2300180V. Determine the symmetrical components of (a) the line-to-line voltages Vab0,Vab1, and Vab2, (b) the line-to-neutral voltages and Van0,Van1, and Van2, (c) and the line currents Ia0,Ia1, and Ia2. (Note that the absence of a neutral connection means that zero-sequence currents are not present.)arrow_forward
- Three single-phase two-winding transformers, each rated 25MVA,34.5/13.8kV, are connected to form a three-phase bank. Balanced positive-suence voltages are applied to the high-voltage terminals, and a balanced, resistive Y load connected to the low-voltage terminals absorbs 75 MW at 13.8 kV. If one of the single-phase transformers is removed (resulting in an open connection) and the balanced load is simultaneously reduced to 43.3 MW (57.7 of the original value), determine (a) the load voltages Va,Vb, and Vc; (b) load currents Ia,Ib, and Ic; and (c) the MVA supplied by each of the remaining two transformers. Are balanced voltages still applied to the load? Is the open transformer overloaded?arrow_forwardConsider a single-phase electric system shown in Figure 3.33. Transformers are rated as follows: XY15MVA,13.8/138kV, leakage reactance 10 YZ15MVA,138/69kV, leakage reactance 8 With the base in circuit Y chosen as 15MVA,138kV determine the per-unit impedance of the 500 resistive load in circuit Z, referred to circuits Z, Y, and X. Neglecting magnetizing currents, transformer resistances, and line impedances, draw the impedance diagram in per unit.arrow_forwardConsider the single-Line diagram of a power system shown in Figure 3.42 with equipment ratings given: Generator G1: 50MVA,13.2kV,x=0.15p.u. Generator G2: 20MVA,13.8kV,x=0.15p.u. Three-phase -Y transformer T1: 80MVA,13.2/165YkV,X=0.1p.u. Three-phase Y- transformer T2: 40MVA,165Y/13.8kV,X=0.1p.u. Load: 40MVA,0.8PFlagging,operatingat150kV Choose a base of 100 MVA for the system and 132-kV base in the transmission-line circuit. Let the load be modeled as a parallel combination of resistance and inductance. Neglect transformer phase shifts. Draw a per-phase equivalent circuit of the system showing all impedances in per unit.arrow_forward
- One advantage of balanced three-phase systems over separate singlephase systems is reduced capital and operating costs of transmission and distribution. (a) True (b) Falsearrow_forwardAnswer with explanation..arrow_forwardA balanced three phase voltage of 360-V line-to-neutral is applied to a balanced Y-connected load with ungrounded neutral, as shown in figure-1. The three phase load consists of three mutually- coupled reactances. Each phase has a series reactance of Z, = j24 N, and the mutual coupling between phases Zm = j6 N. (i) Evaluate the line currents by mesh analysis without using symmetrical components. Evaluate the line currents using symmetrical components. (ii) j6 j24 j6 V. Figure-1arrow_forward
- A three-phase symmetrical double circuit line is arranged in a horizontal plane as shown in figure below. Calculate and derive an expression for the transposed line for the inductance. Assume balanced equally distributed loadsarrow_forward3. A balanced delta connected load of "X" Q- per phase is connected at the end of a three-phase line. The line impedance is "G" - per phase. The line is supplied from a three-phase source with a line-to-line voltage of 207.85 Vrms. Taking phase "a" voltage Va as reference, determine the following: (a) Current in phase a. (b) Total complex power supplied from the source. (c) Magnitude of the line-to-line voltage at the load terminal. X-13+16j G=3+6jarrow_forwardIn single phase AC distribution system, the net drop is the difference of the drop in resistance due to the inphase component and in reactance due to quadrature component of current Select one: True Falsearrow_forward
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