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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Question
Chapter 3, Problem 3.27MCQ
To determine
Whether the given statement is true or false.
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Check out a sample textbook solutionStudents have asked these similar questions
63/
Choose the incorrect statement of a no load single phase transformer from the following
a.
The primary induced emf (E1) is in phase with the secondary induced emf (E2)
b.
The no load current (Io) leads the core loss component of no load current (Ic)
c.
The no load current (Io) lags the core loss component of no load current (Ic)
d.
The secondary induced emf (E2) lags the magnetic flux by 90 degree
7. The primary and secondary induced e.m.fs. El and E2 in a two-winding
transformer are always.....
(a) equal in magnitude
(b) antiphase with each other
(c) in-phase with each other
(d) determined by load on transformer secondary
8. A step-up transformer increases...
(a) voltage
(c) power
(b) current
(d) frequency.
9. The primary and secondary windings of an ordinary -winding transformer
always have...........
(a) different number of turns
(b) same size of copper wire
(c) a common magnetic circuit
(d) separate magnetic circuits.
10. The ordinary efficiency of a given transformer is maximum when...........
(a) it runs at half full-load
(b) it runs at full-load
(c) its Cu loss equals iron loss
(d) it runs slightly overload.
11. The maximum efficiency of a 100-kVA transformer having iron loss of 900
kW and F.L. Cu loss of 1600 W occurs at ....... kVA.
70
12. The kVA rating of an ordinary 2-winding transformer is increased when
connected as an autotransformer because.....
(a) 56.3
(b)…
What's The relation between turn ratio current ratio annd voltage ratio(if it exists) for single phase transformer under the no load test (open circuit test)
Chapter 3 Solutions
Power System Analysis and Design (MindTap Course List)
Ch. 3 - The Ohms law for the magnetic circuit states that...Ch. 3 - For an ideal transformer, the efficiency is (a) 0...Ch. 3 - For an ideal 2-winding transformer, the...Ch. 3 - An ideal transformer has no real or reactive power...Ch. 3 - For an ideal 2-winding transformer, an impedance...Ch. 3 - Consider Figure 3.4. For an ideal phase-shifting...Ch. 3 - Consider Figure 3.5. Match the following, those on...Ch. 3 - The units of admittance, conductance, and...Ch. 3 - Match the following: (i) Hysteresis loss (a) Can...Ch. 3 - For large power transformers rated more than 500...
Ch. 3 - For a short-circuit test on a 2-winding...Ch. 3 - The per-unit quantity is always dimensionless. (a)...Ch. 3 - Consider the adopted per-unit system for the...Ch. 3 - The ideal transformer windings are eliminated from...Ch. 3 - To convert a per-unit impedance from old to new...Ch. 3 - In developing per-unit circuits of systems such as...Ch. 3 - Prob. 3.17MCQCh. 3 - Prob. 3.18MCQCh. 3 - With the American Standard notation, in either a...Ch. 3 - Prob. 3.20MCQCh. 3 - In order to avoid difficulties with third-harmonic...Ch. 3 - Does an open connection permit balanced...Ch. 3 - Does an open- operation, the kVA rating compared...Ch. 3 - It is stated that (i) balanced three-phase...Ch. 3 - In developing per-unit equivalent circuits for...Ch. 3 - In per-unit equivalent circuits of practical...Ch. 3 - Prob. 3.27MCQCh. 3 - Prob. 3.28MCQCh. 3 - For developing per-unit equivalent circuits of...Ch. 3 - Prob. 3.30MCQCh. 3 - Prob. 3.31MCQCh. 3 - Prob. 3.32MCQCh. 3 - The direct electrical connection of the windings...Ch. 3 - Consider Figure 3.25 of the text for a transformer...Ch. 3 - (a) An ideal single-phase two-winding transformer...Ch. 3 - An ideal transformer with N1=1000andN2=250 is...Ch. 3 - Consider an ideal transformer with...Ch. 3 - A single-phase 100-kVA,2400/240-volt,60-Hz...Ch. 3 - Prob. 3.5PCh. 3 - Prob. 3.6PCh. 3 - Consider a source of voltage v(t)=102sin(2t)V,...Ch. 3 - Prob. 3.8PCh. 3 - Prob. 3.9PCh. 3 - A single-phase step-down transformer is rated...Ch. 3 - For the transformer in Problem 3.10. The...Ch. 3 - Prob. 3.12PCh. 3 - A single-phase 50-kVA,2400/240-volt,60-Hz...Ch. 3 - A single-phase 50-kVA,2400/240-volt,60-Hz...Ch. 3 - Rework Problem 3.14 if the transformer is...Ch. 3 - A single-phase, 50-kVA,2400/240-V,60-Hz...Ch. 3 - The transformer of Problem 3.16 is supplying a...Ch. 3 - Using the transformer ratings as base quantities,...Ch. 3 - Using the transformer ratings as base quantities....Ch. 3 - Using base values of 20 kVA and 115 volts in zone...Ch. 3 - Prob. 3.21PCh. 3 - A balanced Y-connected voltage source with...Ch. 3 - Figure 3.32 shows the oneline diagram of a...Ch. 3 - For Problem 3.18, the motor operates at full load,...Ch. 3 - Consider a single-phase electric system shown in...Ch. 3 - A bank of three single-phase transformers, each...Ch. 3 - A three-phase transformer is rated...Ch. 3 - For the system shown in Figure 3.34. draw an...Ch. 3 - Consider three ideal single-phase transformers...Ch. 3 - Reconsider Problem 3.29. If Va,VbandVc are a...Ch. 3 - Prob. 3.31PCh. 3 - Determine the positive- and negative-sequence...Ch. 3 - Consider the three single-phase two-winding...Ch. 3 - Three single-phase, two-winding transformers, each...Ch. 3 - Consider a bank of this single-phase two-winding...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - Consider a three-phase generator rated...Ch. 3 - The leakage reactance of a three-phase,...Ch. 3 - Prob. 3.40PCh. 3 - Consider the single-line diagram of the power...Ch. 3 - For the power system in Problem 3.41, the...Ch. 3 - Three single-phase transformers, each rated...Ch. 3 - A 130-MVA,13.2-kV three-phase generator, which has...Ch. 3 - Figure 3.39 shows a oneline diagram of a system in...Ch. 3 - The motors M1andM2 of Problem 3.45 have inputs of...Ch. 3 - Consider the oneline diagram shown in Figure 3.40....Ch. 3 - With the same transformer banks as in Problem...Ch. 3 - Consider the single-Line diagram of a power system...Ch. 3 - A single-phase three-winding transformer has the...Ch. 3 - The ratings of a three-phase three-winding...Ch. 3 - Prob. 3.52PCh. 3 - The ratings of a three-phase, three-winding...Ch. 3 - An infinite bus, which is a constant voltage...Ch. 3 - A single-phase l0-kVA,2300/230-volt,60-Hz...Ch. 3 - Three single-phase two-winding transformers, each...Ch. 3 - A two-winding single-phase transformer rated...Ch. 3 - A single-phase two-winding transformer rated...Ch. 3 - Prob. 3.59PCh. 3 - PowerWorid Simulator case Problem 3_60 duplicates...Ch. 3 - Rework Example 3.12 for a+10 tap, providing a 10...Ch. 3 - A 23/230-kV step-up transformer feeds a...Ch. 3 - The per-unit equivalent circuit of two...Ch. 3 - Reconsider Problem 3.64 with the change that now...Ch. 3 - What are the advantages of correctly specifying a...Ch. 3 - Why is it important to reduce the moisture within...Ch. 3 - What should be the focus of transformer preventive...
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- In developing per-unit circuits of systems such as the one shown in Figure 3.10. when moving across a transformer, the voltage base is changed in proportion to the transformer voltage ratings. (a) True (b) Falsearrow_forwardWhat should be the focus of transformer preventive maintenance efforts?arrow_forwardFor developing per-unit equivalent circuits of single-phase three-winding transformer, a common Sbase is selected for all three windings and voltage bases are selected in proportion to the rated voltage of the windings (a) True (b) Falsearrow_forward
- 3. Why the copper loss in the primary can be neglected, in the open circuit test? 4. Why the terms Rm and Xm significant when the transformer is loaded?arrow_forwardWhat is the difference between two transformer with same voltage level and same rating current, but the MVAs different? ..arrow_forwardFind the following : 1.Ripple Voltage (vpp) 2. Zero-to peak ripple(Vop) 3.secondary winding of the transformer high line and low linearrow_forward
- Draw the equivalent circuit for a single-phase transformer with all the components referred to the primary side. Give a brief description of what each circuit component represents, and indicate how the secondary voltage and current are subsequently calculated from the primary side values.arrow_forwardChoose the correct statement of a no load single phase transformer from the following O a. The magnetizing component of no load current (Im) leads the core loss component of no load current (Ic) O b. The magnetizing component of no load current (Im) lags the core lossComponent of no load current (Ic) O c. The magnetizing component of no load current (Im) and the core loss component of no load current (Ic) are in phase each other O d. The magnetizing component of no load current (Im) leads the core loss component ofarrow_forwardIn no load phasor diagram of practical transformer, the magnetizing current Imag is ____________________ with primary voltage Vp. 90degreeout of phase Leading by 60degree In phase Lagging by 60degreearrow_forward
- 1. For this question you are to sketch two transformers (T1 and T2) side by side connected in PARALLEL. Be sure to employ alphanumeric polarity markings for each transformer with the LV windings on the TOP and the HV windings on the BOTTOM. T1 should have ADDITIVE polarity and T2 should have SUBTRACTIVE polarity. Include a source bus voltage [REFERENCE] above the transformers and a single-phase load. Indicate the direction of all voltages with respect to the reference direction. Based on the preceding requirements, provide a complete SCHEMATIC diagram showing how the two transformers should be connected for proper PARALLEL operation.arrow_forwardQ5:Choose the correct answer from the given alternatives (answer five only) 1.In an ideal transformer, (a) windings have no resistance (b) core has infinite permeability (d) all of the above. (c) core has no losses 2. The primary and secondary induced e.m.fs. El and E2 in a two-winding transformer are always: (a) equal in magnitude (b) in-phase with each other (c) antiphase with each other (d) determined by load on transformer secondary. 3. In relation to a transformer, the ratio 20 : 1 indicates that (a) there are 20 turns on primary one turn on secondary (b) secondary voltage is 1/20th of primary voltage (c) primary current is 20 times greater than the secondary current. (d) for every 20 turns on primary, there is one turn on secondary. 4. A transformer has negative voltage regulation when its load power factor is: (a) zero (b) lagging. (d) unity (c) leadingarrow_forwardThree transformers, e ach rated 25 MVA, 38. 1 /3.81 kV, are connected Star – Delta with a balanced load of three 0.79 ohm (load resistance RL) star connected resistors. Choose a base of 75 MVA, 66 kV for the high-voltage side of the transformer and specify the base for the low-voltage side. Determine the per-unit resistance of the load on the base for the low-voltage side. Then, determine the load resistance RL in ohms referred to the high-voltage side and the per-unit value of this resistance on the chosen base.arrow_forward
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