Electrical Machines, Drives, and Power Systems

by Wildi, Theodore

• ISBN13: 9780130824608
• ISBN10: 0130824607
• Edition: 4th
• Format: Hardcover
• Copyright: 1999-09-01
• Publisher: Pearson College Div

Summary

For one-semester, undergraduate-level courses in Motor Controls, Electric Machines, Power Electronics, and Electric Power. This best-selling text employs a theoretical, practical, multidisciplinary approach to provide introductory students with a broad understanding of modern electric power. The scope of the book reflects the rapid changes that have occurred in power technology over the past few yearsallowing the entrance of power electronics into every facet of industrial drives, and expanding the field to open more career opportunities.

Table of Contents

PART I. FUNDAMENTALS	3	(68)
1. UNITS	3	(12)
1.0 Introduction	3	(1)
1.1 Systems of units	3	(1)
1.2 Getting used to SI	4	(1)
1.3 Base and derived units of the SI	4	(1)
1.4 Definitions of base units	5	(1)
1.5 Definitions of derived units	5	(2)
1.6 Multiples and submultiples of SI units	7	(1)
1.7 Commonly used units	7	(1)
1.8 Conversion charts and their use	8	(1)
1.9 The per-unit system of measurement	9	(1)
1.10 Per-unit system with one base	10	(1)
1.11 Per-unit system with two bases	11	(1)
Questions and Problems	12	(3)
2. FUNDAMENTALS OF ELECTRICITY, MAGNETISM, AND CIRCUITS	15	(35)
2.0 Introduction	15	(1)
2.1 Conventional and electron current flow	15	(1)
2.2 Distinction between sources and loads	16	(1)
2.3 Sign notation	17	(1)
2.4 Double-subscript notation for voltages	17	(1)
2.5 Sign notation for voltages	17	(1)
2.6 Graph of an alternating voltage	18	(1)
2.7 Positive and negative currents	19	(1)
2.8 Sinusoidal voltage	19	(1)
2.9 Converting cosine functions into sine functions	20	(1)
2.10 Effective value of an ac voltage	20	(1)
2.11 Phasor representation	21	(2)
2.12 Harmonics	23	(2)
2.13 Energy in an inductor	25	(1)
2.14 Energy in a capacitor	25	(1)
2.15 Some useful equations	26	(1)
ELECTROMAGNETISM
2.16 Magnetic field intensity H and flux density B	27	(1)
2.17 B-H curve of vacuum	27	(1)
2.18 B-H curve of a magnetic material	27	(1)
2.19 Determining the relative permeability	28	(1)
2.20 Faraday's law of electromagnetic induction	29	(1)
2.21 Voltage induced in a conductor	30	(1)
2.22 Lorentz force on a conductor	31	(1)
2.23 Direction of the force acting on a straight conductor	31	(1)
2.24 Residual flux density and coercive force	32	(1)
2.25 Hysteresis loop	33	(1)
2.26 Hysteresis loss	33	(1)
2.27 Hysteresis losses caused by rotation	33	(1)
2.28 Eddy currents	34	(1)
2.29 Eddy currents in a stationary iron core	35	(1)
2.30 Eddy-current losses in a revolving core	35	(1)
2.31 Current in an inductor	36	(4)
CIRCUITS AND EQUATIONS
2.32 Kirchhoff's voltage law	40	(1)
2.33 Kirchhoff's voltage law and double-subscript notation	40	(1)
2.34 Kirchhoff's current law	41	(1)
2.35 Currents, impedances, and associated voltages	41	(2)
2.36 Kirchhoff's laws and ac circuits	43	(1)
2.37 KVL and sign notation	43	(1)
2.38 Solving ac and dc circuits with sign notation	44	(1)
2.39 Circuits and hybrid notation	45	(1)
Questions and Problems	46	(4)
3. FUNDAMENTALS OF MECHANICS AND HEAT	50	(21)
3.0 Introduction	50	(1)
3.1 Force	50	(1)
3.2 Torque	51	(1)
3.3 Mechanical work	51	(1)
3.4 Power	52	(1)
3.5 Power of a motor	52	(1)
3.6 Transformation of energy	53	(1)
3.7 Efficiency of a machine	53	(1)
3.8 Kinetic energy of linear motion	54	(1)
3.9 Kinetic energy of rotation, moment of inertia	54	(3)
3.10 Torque, inertia, and change in speed	57	(1)
3.11 Speed of a motor/load system	57	(1)
3.12 Power flow in a mechanically coupled system	58	(1)
3.13 Motor driving a load having inertia	58	(1)
3.14 Electric motors driving linear motion loads	59	(1)
3.15 Heat and temperature	60	(1)
3.16 Temperature scales	61	(1)
3.17 Heat required to raise the temperature of a body	61	(1)
3.18 Transmission of heat	62	(1)
3.19 Heat transfer by conduction	62	(1)
3.20 Heat transfer by convection	63	(1)
3.21 Calculating the losses by convection	63	(1)
3.22 Heat transfer by radiation	64	(1)
3.23 Calculating radiation losses	64	(1)
Questions and Problems	65	(6)
PART II. ELECTRICAL MACHINES AND TRANSFORMERS	71	(125)
4. DIRECT-CURRENT GENERATORS	71	(25)
4.0 Introduction	71	(1)
4.1 Generating an ac voltage	71	(1)
4.2 Direct-current generator	72	(1)
4.3 Difference between ac and dc generators	73	(1)
4.4 Improving the waveshape	73	(2)
4.5 Induced voltage	75	(1)
4.6 Neutral zones	76	(1)
4.7 Value of the induced voltage	76	(1)
4.8 Generator under load: the energy conversion process	77	(1)
4.9 Armature reaction	77	(1)
4.10 Shifting the brushes to improve commutation	78	(1)
4.11 Commutating poles	79	(1)
4.12 Separately excited generator	79	(1)
4.13 No-load operation and saturation curve	79	(1)
4.14 Shunt generator	80	(1)
4.15 Controlling the voltage of a shunt generator	81	(1)
4.16 Equivalent circuit	82	(1)
4.17 Separately excited generator under load	82	(1)
4.18 Shunt generator under load	83	(1)
4.19 Compound generator	83	(1)
4.20 Differential compound generator	84	(1)
4.21 Load characteristics	84	(1)
4.22 Generator specifications	84	(1)
CONSTRUCTION OF DIRECT-CURRENT GENERATORS
4.23 Field	84	(1)
4.24 Armature	85	(1)
4.25 Commutator and brushes	86	(2)
4.26 Details of a multipole generator	88	(3)
4.27 The ideal commutation process	91	(1)
4.28 The practical commutation process	92	(1)
Questions and Problems	93	(3)
5. DIRECT-CURRENT MOTORS	96	(24)
5.0 Introduction	96	(1)
5.1 Counter-electromotive force (cemf)	96	(1)
5.2 Acceleration of the motor	97	(1)
5.3 Mechanical power and torque	98	(2)
5.4 Speed of rotation	100	(1)
5.5 Armature speed control	101	(1)
5.6 Field speed control	102	(1)
5.7 Shunt motor under load	103	(1)
5.8 Series motor	104	(1)
5.9 Series motor speed control	105	(1)
5.10 Applications of the series motor	106	(1)
5.11 Compound motor	106	(1)
5.12 Reversing the direction of rotation	107	(1)
5.13 Starting a shunt motor	108	(1)
5.14 Face-plate starter	108	(1)
5.15 Stopping a motor	109	(1)
5.16 Dynamic braking	109	(1)
5.17 Plugging	110	(1)
5.18 Dynamic braking and mechanical time constant	111	(2)
5.19 Armature reaction	113	(1)
5.20 Flux distortion due to armature reaction	113	(1)
5.21 Commutating poles	113	(1)
5.22 Compensating winding	114	(1)
5.23 Basics of variable speed control	114	(3)
5.24 Permanent magnet motors	117	(1)
Questions and Problems	118	(2)
6. EFFICIENCY AND HEATING OF ELECTRICAL MACHINES	120	(14)
6.0 Introduction	120	(1)
6.1 Mechanical losses	120	(1)
6.2 Electrical losses	120	(3)
6.3 Losses as a function of load	123	(1)
6.4 Efficiency curve	123	(2)
6.5 Temperature rise	125	(1)
6.6 Life expectancy of electric equipment	126	(1)
6.7 Thermal classification of insulators	126	(1)
6.8 Maximum ambient temperature and hot-spot temperature rise	127	(2)
6.9 Temperature rise by the resistance method	129	(1)
6.10 Relationship between the speed and size of a machine	130	(1)
Questions and Problems	131	(3)
7. ACTIVE, REACTIVE, AND APPARENT POWER	134	(24)
7.0 Introduction	134	(1)
7.1 Instantaneous power	134	(2)
7.2 Active power	136	(1)
7.3 Reactive power	137	(1)
7.4 Definition of reactive load and reactive source	138	(1)
7.5 The capacitor and reactive power	139	(1)
7.6 Distinction between active and reactive power	140	(1)
7.7 Combined active and reactive loads: apparent power	141	(1)
7.8 Relationship between P, Q, and S	141	(2)
7.9 Power factor	143	(1)
7.10 Power triangle	144	(1)
7.11 Further aspects of sources and loads	144	(2)
7.12 Systems comprising several loads	146	(2)
7.13 Reactive power without magnetic fields	148	(1)
7.14 Solving AC circuits using the power triangle method	148	(3)
7.15 Power and vector notation	151	(3)
7.16 Rules on sources and loads (sign notation)	154	(1)
7.17 Rules on sources and loads (double subscript notation)	154	(1)
Questions and Problems	155	(3)
8. THREE-PHASE CIRCUITS	158	(25)
8.0 Introduction	158	(1)
8.1 Polyphase systems	158	(1)
8.2 Single-phase generator	159	(1)
8.3 Power output of a single-phase generator	160	(1)
8.4 Two-phase generator	160	(1)
8.5 Power output of a 2-phase generator	161	(1)
8.6 Three-phase generator	162	(1)
8.7 Power output of a 3-phase generator	162	(2)
8.8 Wye connection	164	(1)
8.9 Voltage relationships	165	(2)
8.10 Delta connection	167	(1)
8.11 Power transmitted by a 3-phase line	168	(1)
8.12 Active, reactive and apparent power in 3-phase circuits	169	(1)
8.13 Solving 3-phase circuits	170	(1)
8.14 Industrial loads	171	(3)
8.15 Phase sequence	174	(1)
8.16 Determining the phase sequence	175	(1)
8.17 Power measurement in ac circuits	176	(1)
8.18 Power measurement in 3-phase, 3-wire circuits	176	(1)
8.19 Power measurement in 3-phase, 4-wire circuits	177	(1)
8.20 Varmeter	177	(1)
8.21 A remarkable single-phase to 3-phase transformation	178	(2)
Questions and Problems	180	(3)
9. THE IDEAL TRANSFORMER	183	(14)
9.0 Introduction	183	(1)
9.1 Voltage induced in a coil	183	(1)
9.2 Applied voltage and induced voltage	184	(1)
9.3 Elementary transformer	185	(1)
9.4 Polarity of a transformer	186	(1)
9.5 Properties of polarity marks	186	(1)
9.6 Ideal transformer at no-load; voltage ratio	187	(1)
9.7 Ideal transformer under load; current ratio	188	(3)
9.8 Circuit symbol for an ideal transformer	191	(1)
9.9 Impedance ratio	191	(1)
9.10 Shifting impedances from secondary to primary and vice versa	192	(3)
Questions and Problems	195	(2)
10. PRACTICAL TRANSFORMERS	197	(28)
10.0 Introduction	197	(1)
10.1 Ideal transformer with an imperfect core	197	(2)
10.2 Ideal transformer with loose coupling	199	(1)
10.3 Primary and secondary leakage reactance	200	(2)
10.4 Equivalent circuit of a practical transformer	202	(1)
10.5 Construction of a power transformer	203	(1)
10.6 Standard terminal markings	204	(1)
10.7 Polarity tests	204	(1)
10.8 Transformer taps	205	(1)
10.9 Losses and transformer rating	206	(1)
10.10 No-load saturation curve	206	(1)
10.11 Cooling methods	207	(2)
10.12 Simplifying the equivalent circuit	209	(2)
10.13 Voltage regulation	211	(1)
10.14 Measuring transformer impedances	212	(3)
10.15 Introducing the per unit method	215	(1)
10.16 Impedance of a transformer	216	(1)
10.17 Typical per-unit impedances	216	(3)
10.18 Transformers in parallel	219	(2)
Questions and Problems	221	(4)
11. SPECIAL TRANSFORMERS	225	(18)
11.0 Introduction	225	(1)
11.1 Dual-voltage distribution transformer	225	(1)
11.2 Autotransformer	226	(2)
11.3 Conventional transformer connected as an autotransformer	228	(2)
11.4 Voltage transformers	230	(1)
11.5 Current transformers	231	(2)
11.6 Opening the secondary of a CT can be dangerous	233	(1)
11.7 Toroidal current transformers	234	(1)
11.8 Variable autotransformer	235	(1)
11.9 High-impedance transformers	236	(1)
11.10 Induction heating transformers	237	(1)
11.11 High-frequency transformers	238	(3)
Questions and Problems	241	(2)
12. THREE-PHASE TRANSFORMERS	243	(20)
12.0 Introduction	243	(1)
12.1 Basic properties of 3-phase transformer banks	243	(1)
12.2 Delta-delta connection	244	(2)
12.3 Delta-wye connection	246	(1)
12.4 Wye-delta connection	247	(1)
12.5 Wye-wye connection	248	(1)
12.6 Open-delta connection	248	(1)
12.7 Three-phase transformers	249	(2)
12.8 Step-up and step-down autotransformer	251	(2)
12.9 Phase-shift principle	253	(1)
12.10 Three-phase to 2-phase transformation	254	(2)
12.11 Phase-shift transformer	256	(2)
12.12 Calculations involving 3-phase transformers	258	(2)
12.13 Polarity marking of 3-phase transformers	260	(1)
Questions and Problems	260	(3)
13. THREE-PHASE INDUCTION MOTORS	263	(36)
13.0 Introduction	263	(1)
13.1 Principal components	263	(1)
13.2 Principle of operation	264	(1)
13.3 The rotating field	265	(5)
13.4 Direction of rotation	270	(1)
13.5 Number of poles-synchronous speed	271	(2)
13.6 Starting characteristics of a squirrelcage motor	273	(1)
13.7 Acceleration of the rotor-slip	274	(1)
13.8 Motor under load	274	(1)
13.9 Slip	274	(1)
13.10 Voltage and frequency induced in the rotor	275	(1)
13.11 Characteristics of squirrel-cage induction motors	276	(1)
13.12 Estimating the currents in an induction motor	277	(1)
13.13 Active power flow	278	(3)
13.14 Torque versus speed curve	281	(1)
13.15 Effect of rotor resistance	282	(2)
13.16 Wound-rotor motor	284	(1)
13.17 Three-phase windings	285	(3)
13.18 Sector motor	288	(1)
13.19 Linear induction motor	289	(2)
13.20 Traveling waves	291	(1)
13.21 Properties of a linear induction motor	291	(2)
13.22 Magnetic levitation	293	(2)
Questions and Problems	295	(4)
14. SELECTION AND APPLICATION OF THREE-PHASE INDUCTION MOTORS	299	(23)
14.0 Introduction	299	(1)
14.1 Standardization and classification of induction motors	299	(1)
14.2 Classification according to environment and cooling methods	299	(2)
14.3 Classification according to electrical and mechanical properties	301	(2)
14.4 Choice of motor speed	303	(1)
14.5 Two-speed motors	303	(2)
14.6 Induction motor characteristics under various load conditions	305	(3)
14.7 Starting an induction motor	308	(1)
14.8 Plugging an induction motor	308	(1)
14.9 Braking with direct current	309	(1)
14.10 Abnormal conditions	310	(1)
14.11 Mechanical overload	310	(1)
14.12 Line voltage changes	310	(1)
14.13 Single-phasing	310	(1)
14.14 Frequency variation	311	(1)
14.15 Induction motor operating as a generator	311	(3)
14.16 Complete torque-speed characteristic of an induction machine	314	(1)
14.17 Features of a wound-rotor induction motor	315	(1)
14.18 Start-up of high-inertia loads	315	(1)
14.19 Variable-speed drives	315	(1)
14.20 Frequency converter	315	(3)
Questions and Problems	318	(4)
15. EQUIVALENT CIRCUIT OF THE INDUCTION MOTOR	322	(13)
15.0 Introduction	322	(1)
15.1 The wound-rotor induction motor	322	(3)
15.2 Power relationships	325	(1)
15.3 Phasor diagram of the induction motor	326	(1)
15.4 Breakdown torque and speed	327	(1)
15.5 Equivalent circuit of two practical motors	327	(1)
15.6 Calculation of the breakdown torque	328	(1)
15.7 Torque-speed curve and other characteristics	329	(1)
15.8 Properties of an asynchronous generator	330	(1)
15.9 Tests to determine the equivalent circuit	331	(2)
Questions and Problems	333	(2)
16. SYNCHRONOUS GENERATORS	335	(34)
16.0 Introduction	335	(1)
16.1 Commercial synchronous generators	335	(1)
16.2 Number of poles	335	(1)
16.3 Main features of the stator	336	(4)
16.4 Main features of the rotor	340	(2)
16.5 Field excitation and exciters	342	(1)
16.6 Brushless excitation	343	(1)
16.7 Factors affecting the size of synchronous generators	344	(1)
16.8 No-load saturation curve	345	(1)
16.9 Synchronous reactance-equivalent circuit of an ac generator	346	(2)
16.10 Determining the value of X(s)	348	(1)
16.11 Base impedance, per-unit X(s)	349	(1)
16.12 Short-circuit ratio	350	(1)
16.13 Synchronous generator under load	350	(2)
16.14 Regulation curves	352	(1)
16.15 Synchronization of a generator	353	(2)
16.16 Synchronous generator on an infinite bus	355	(1)
16.17 Infinite bus-effect of varying the exciting current	355	(1)
16.18 Infinite bus-effect of varying the mechanical torque	355	(2)
16.19 Physical interpretation of alternator behavior	357	(1)
16.20 Active power delivered by the generator	358	(1)
16.21 Control of active power	359	(1)
16.22 Transient reactance	359	(2)
16.23 Power transfer between two sources	361	(1)
16.24 Efficiency, power, and size of electrical machines	362	(2)
Questions and Problems	364	(5)
17. SYNCHRONOUS MOTORS	369	(22)
17.0 Introduction	369	(1)
17.1 Construction	370	(2)
17.2 Starting a synchronous motor	372	(1)
17.3 Pull-in torque	372	(1)
17.4 Motor under load-general description	372	(1)
17.5 Motor under load-simple calculations	373	(3)
17.6 Power and torque	376	(1)
17.7 Mechanical and electrical angles	377	(1)
17.8 Reluctance torque	378	(1)
17.9 Losses and efficiency of a synchronous motor	379	(1)
17.10 Excitation and reactive power	380	(1)
17.11 Power factor rating	381	(1)
17.12 V-curves	382	(1)
17.13 Stopping synchronous motors	383	(2)
17.14 The synchronous motor versus the induction motor	385	(1)
17.15 Synchronous capacitor	385	(3)
Questions and Problems	388	(3)
18. SINGLE-PHASE MOTORS	391	(26)
18.0 Introduction	391	(1)
18.1 Construction of a single-phase induction motor	391	(2)
18.2 Synchronous speed	393	(1)
18.3 Torque-speed characteristic	394	(1)
18.4 Principle of operation	394	(2)
18.5 Locked-rotor torque	396	(1)
18.6 Resistance split-phase motor	396	(2)
18.7 Capacitor-start motor	398	(1)
18.8 Efficiency and power factor of single-phase induction motors	399	(2)
18.9 Vibration of single-phase motors	401	(1)
18.10 Capacitor-run motor	402	(1)
18.11 Reversing the direction of rotation	403	(1)
18.12 Shaded-pole motor	403	(1)
18.13 Universal motor	404	(1)
18.14 Hysteresis motor	405	(2)
18.15 Synchronous reluctance motor	407	(1)
18.16 Synchro drive	408	(1)
EQUIVALENT CIRCUIT OF A SINGLE-PHASE MOTOR
18.17 Magnetomotive force distribution	409	(1)
18.18 Revolving mmfs in a single-phase motor	410	(1)
18.19 Deducing the circuit diagram of a single-phase motor	411	(3)
Questions and Problems	414	(3)
19. STEPPER MOTORS	417	(22)
19.0 Introduction	417	(1)
19.1 Elementary stepper motor	417	(1)
19.2 Effect of inertia	418	(1)
19.3 Effect of a mechanical load	419	(1)
19.4 Torque versus current	420	(1)
19.5 Start-stop stepping rate	420	(1)
19.6 Slew speed	421	(1)
19.7 Ramping	422	(1)
19.8 Types of stepper motors	422	(2)
19.9 Motor windings and associated drives	424	(3)
19.10 High-speed operation	427	(1)
19.11 Modifying the time constant	428	(1)
19.12 Bilevel drive	428	(6)
19.13 Instability and resonance	434	(1)
19.14 Stepper motors and linear drives	434	(1)
Questions and Problems	434	(5)
PART III. ELECTRICAL AND ELECTRONIC DRIVES	439	(196)
20. BASICS OF INDUSTRIAL MOTOR CONTROL	439	(33)
20.0 Introduction	439	(1)
20.1 Control devices	439	(4)
20.2 Normally-open and normally-closed contacts	443	(1)
20.3 Relay coil exciting current	443	(2)
20.4 Control diagrams	445	(1)
20.5 Starting methods	446	(1)
20.6 Manual across-the-line starters	447	(1)
20.7 Magnetic across-the-line starters	448	(2)
20.8 Inching and jogging	450	(1)
20.9 Reversing the direction of rotation	451	(2)
20.10 Plugging	453	(1)
20.11 Reduced-voltage starting	454	(1)
20.12 Primary resistance starting	454	(4)
20.13 Autotransformer starting	458	(2)
20.14 Other starting methods	460	(1)
20.15 Cam switches	461	(1)
ELECTRIC DRIVES
20.16 Fundamentals of electric drives	462	(1)
20.17 Typical torque-speed curves	463	(1)
20.18 Shape of the torque-speed curve	464	(2)
20.19 Current-speed curves	466	(1)
20.20 Regenerative braking	467	(1)
Questions and Problems	468	(4)
21. FUNDAMENTAL ELEMENTS OF POWER ELECTRONICS	472	(69)
21.0 Introduction	472	(1)
21.1 Potential level	472	(2)
21.2 Voltage across some circuit elements	474	(1)
THE DIODE AND DIODE CIRCUITS
21.3 The diode	475	(1)
21.4 Main characteristics of a diode	476	(1)
21.5 Battery charger with series resistor	476	(2)
21.6 Battery charger with series inductor	478	(2)
21.7 Single-phase bridge rectifier	480	(1)
21.8 Filters	481	(2)
21.9 Three-phase, 3-pulse diode rectifier	483	(2)
21.10 Three-phase, 6-pulse rectifier	485	(4)
21.11 Effective line current, fundamental line current	489	(1)
21.12 Distortion power factor	490	(1)
21.13 Displacement power factor, total power factor	490	(1)
21.14 Harmonic content, THD	491	(1)
THE THYRISTOR AND THYRISTOR CIRCUITS
21.15 The thyristor	492	(1)
21.16 Principles of gate firing	492	(2)
21.17 Power gain of a thyristor	494	(1)
21.18 Current interruption and forced commutation	495	(1)
21.19 Basic thyristor power circuits	496	(1)
21.20 Controlled rectifier supplying a passive load (Circuit 1, Table 21 D)	496	(1)
21.21 Controlled rectifier supplying an active load (Circuit 2, Table 21D)	497	(1)
21.22 Line-commutated inverter (Circuit 3, Table 21D)	498	(2)
21.23 AC static switch (Circuit 4, Table 21D)	500	(1)
21.24 Cycloconverter (Circuit 5, Table 21D)	501	(1)
21.25 Three-phase, 6-pulse controllable converter (Circuit 6, Table 21D)	502	(1)
21.26 Basic principle of operation	503	(1)
21.27 Three-phase, 6-pulse rectifier feeding an active load	504	(1)
21.28 Delayed triggering-rectifier mode	505	(2)
21.29 Delayed triggering-inverter mode	507	(1)
21.30 Triggering range	508	(1)
21.31 Equivalent circuit of a converter	509	(2)
21.32 Currents in a 3-phase, 6-pulse converter	511	(1)
21.33 Power factor	511	(3)
21.34 Commutation overlap	514	(1)
21.35 Extinction angle	514	(1)
DC-TO-DC SWITCHING CONVERTERS
21.36 Semiconductor switches	515	(2)
21.37 DC-to-DC switching converter	517	(2)
21.38 Rapid switching	519	(3)
21.39 Impedance transformation	522	(1)
21.40 Basic 2-quadrant dc-to-dc converter	522	(3)
21.41 Two-quadrant electronic converter	525	(1)
21.42 Four-quadrant dc-to-dc converter	526	(2)
21.43 Switching losses	528	(1)
DC-TO-AC SWITCHING CONVERTERS
21.44 Dc-to-ac rectangular wave converter	529	(1)
21.45 Dc-to-ac converter with pulse-width modulation	530	(2)
21.46 Dc-to-ac sine wave converter	532	(1)
21.47 Generating a sine wave	533	(1)
21.48 Creating the PWM pulse train	534	(1)
21.49 Dc-to-ac 3-phase converter	535	(2)
21.50 Conclusion	537	(1)
Questions and Problems	537	(4)
22. ELECTRONIC CONTROL OF DIRECT-CURRENT MOTORS	541	(34)
22.0 Introduction	541	(1)
22.1 First quadrant speed control	541	(3)
22.2 Two-quadrant control-field reversal	544	(1)
22.3 Two-quadrant control-armature reversal	545	(1)
22.4 Two-quadrant control-two converters	545	(1)
22.5 Four-quadrant control-two converters with circulating current	546	(3)
22.6 Two-quadrant control with positive torque	549	(1)
22.7 Four-quadrant drive	549	(2)
22.8 Six-pulse converter with freewheeling diode	551	(5)
22.9 Half-bridge converter	556	(2)
22.10 DC traction	558	(2)
22.11 Motor drive using a dc-to-dc switching converter	560	(5)
22.12 Introduction to brushless dc motors	565	(1)
22.13 Commutator replaced by reversing switches	566	(2)
22.14 Synchronous motor as a brushless dc machine	568	(1)
22.15 Standard synchronous motor and brushless dc machine	569	(1)
22.16 Practical application of a brushless dc motor	569	(2)
Questions and Problems	571	(4)
23. ELECTRONIC CONTROL OF ALTERNATING CURRENT MOTORS	575	(60)
23.0 Introduction	575	(1)
23.1 Types of ac drives	575	(2)
23.2 Synchronous motor drive using current-source dc link	577	(3)
23.3 Synchronous motor and cycloconverter	580	(1)
23.4 Cycloconverter voltage and frequency control	580	(2)
23.5 Squirrel-cage induction motor with cycloconverter	582	(7)
23.6 Squirrel-cage motor and static voltage controller	589	(1)
23.7 Soft-starting cage motors	590	(2)
SELF-COMMUTATED INVERTERS
23.8 Self-commutated inverters for cage motors	592	(1)
23.9 Current-source self-commutated frequency converter (rectangular wave)	593	(1)
23.10 Voltage-source self-commutated frequency converter (rectangular wave)	594	(3)
23.11 Chopper speed control of a wound-rotor induction motor	597	(2)
23.12 Recovering power in a wound-rotor induction motor	599	(3)
PULSE-WIDTH MODULATION DRIVES
23.13 Review of pulse-width modulation	602	(2)
23.14 Pulse-width modulation and induction motors	604	(1)
TORQUE AND SPEED CONTROL OF INDUCTION MOTORS
23.15 Dc motor and flux orientation	604	(1)
23.16 Slip speed, flux orientation, and torque	605	(2)
23.17 Features of variable-speed control-constant torque mode	607	(3)
23.18 Features of variable-speed control-constant horsepower mode	610	(1)
23.19 Features of variable-speed control-generator mode	610	(1)
23.20 Induction motor and its equivalent circuit	611	(1)
23.21 Equivalent circuit of a practical motor	612	(1)
23.22 Volts per hertz of a practical motor	613	(1)
23.23 Speed and torque control of induction motors	614	(1)
23.24 Carrier frequencies	615	(1)
23.25 Dynamic control of induction motors	615	(1)
23.26 Principle of flux vector control	616	(2)
23.27 Variable-speed drive and electric traction	618	(3)
23.28 Principal components	621	(1)
23.29 Operating mode of the 3-phase converter	622	(2)
23.30 Operating mode of the single-phase converter	624	(5)
23.31 Conclusion	629	(1)
Questions and Problems	629	(6)
PART IV. ELECTRIC UTILITY POWER SYSTEMS	635	(196)
24. GENERATION OF ELECTRICAL ENERGY	635	(29)
24.0 Introduction	635	(1)
24.1 Demand of an electrical system	635	(2)
24.2 Location of the generating station	637	(1)
24.3 Types of generating stations	637	(1)
24.4 Controlling the power balance between generator and load	638	(1)
24.5 Advantage of interconnected systems	639	(2)
24.6 Conditions during an outage	641	(1)
24.7 Frequency and electric clocks	642	(1)
HYDROPOWER GENERATING STATIONS
24.8 Available hydro power	642	(1)
24.9 Types of hydropower stations	643	(1)
24.10 Makeup of a hydropower plant	644	(2)
24.11 Pumped-storage installations	646	(2)
THERMAL GENERATING STATIONS
24.12 Makeup of a thermal generating station	648	(2)
24.13 Turbines	650	(1)
24.14 Condenser	650	(1)
24.15 Cooling towers	650	(1)
24.16 Boiler-feed pump	651	(1)
24.17 Energy flow diagram for a steam plant	651	(1)
24.18 Thermal stations and the environment	652	(3)
NUCLEAR GENERATING STATIONS
24.19 Composition of an atomic nucleus; isotopes	655	(1)
24.20 The source of uranium	655	(1)
24.21 Energy released by atomic fission	656	(1)
24.22 Chain reaction	656	(1)
24.23 Types of nuclear reactors	657	(1)
24.24 Example of a light-water reactor	658	(1)
24.25 Example of a heavy-water reactor	659	(1)
24.26 Principle of the fast breeder reactor	660	(1)
24.27 Nuclear fusion	661	(1)
Questions and Problems	661	(3)
25. TRANSMISSION OF ELECTRICAL ENERGY	664	(34)
25.0 Introduction	664	(1)
25.1 Principal components of a power distribution system	664	(1)
25.2 Types of power lines	665	(2)
25.3 Standard voltages	667	(1)
25.4 Components of a HV transmission line	667	(1)
25.5 Construction of a line	668	(1)
25.6 Galloping lines	669	(1)
25.7 Corona effect-radio interference	669	(1)
25.8 Pollution	669	(1)
25.9 Lightning strokes	670	(1)
25.10 Lightning arresters on buildings	671	(1)
25.11 Lightning and transmission lines	671	(1)
25.12 Basic impulse insulation level (BIL)	672	(1)
25.13 Ground wires	673	(1)
25.14 Tower grounding	673	(2)
25.15 Fundamental objectives of a transmission line	675	(1)
25.16 Equivalent circuit of a line	676	(1)
25.17 Typical impedance values	676	(2)
25.18 Simplifying the equivalent circuit	678	(2)
25.19 Voltage regulation and power-transmission capability of transmission lines	680	(1)
25.20 Resistive line	680	(1)
25.21 Inductive line	681	(2)
25.22 Compensated inductive line	683	(2)
25.23 Inductive line connecting two systems	685	(1)
25.24 Review of power transmission	686	(1)
25.25 Choosing the line voltage	687	(2)
25.26 Methods of increasing the power capacity	689	(1)
25.27 Extra-high-voltage lines	689	(3)
25.28 Power exchange between power centers	692	(1)
25.29 Practical example of power exchange	693	(2)
Questions and Problems	695	(3)
26. DISTRIBUTION OF ELECTRICAL ENERGY	698	(31)
26.0 Introduction	698	(1)
SUBSTATIONS
26.1 Substation equipment	698	(1)
26.2 Circuit breakers	698	(4)
26.3 Air-break switches	702	(1)
26.4 Disconnecting switches	702	(1)
26.5 Grounding switches	702	(1)
26.6 Surge arresters	702	(3)
26.7 Current-limiting reactors	705	(1)
26.8 Grounding transformer	706	(1)
26.9 Example of a substation	707	(2)
26.10 Medium-voltage distribution	709	(1)
26.11 Low-voltage distribution	709	(5)
PROTECTION OF MEDIUM-VOLTAGE DISTRIBUTION SYSTEMS
26.12 Coordination of the protective devices	714	(1)
26.13 Fused cutouts	715	(1)
26.14 Reclosers	716	(1)
26.15 Sectionalizers	716	(1)
26.16 Review of MV protection	717	(1)
LOW-VOLTAGE DISTRIBUTION
26.17 LV distribution system	717	(2)
26.18 Grounding electrical installations	719	(1)
26.19 Electric shock	719	(1)
26.20 Grounding of 120 V and 240 V/120 V systems	720	(1)
26.21 Equipment grounding	721	(2)
26.22 Ground-fault circuit breaker	723	(1)
26.23 Rapid conductor heating: I^(2)t factor	724	(1)
26.24 The role of fuses	725	(1)
26.25 Electrical installation in buildings	725	(1)
26.26 Principal components of an electrical installation	725	(2)
Questions and Problems	727	(2)
27. THE COST OF ELECTRICITY	729	(17)
27.0 Introduction	729	(1)
27.1 Tariff based upon energy	730	(1)
27.2 Tariff based upon demand	730	(1)
27.3 Demand meter	730	(2)
27.4 Tariff based upon power factor	732	(1)
27.5 Typical rate structures	733	(1)
27.6 Demand controllers	733	(4)
27.7 Power factor correction	737	(3)
27.8 Measuring electrical energy, the watthourmeter	740	(1)
27.9 Operation of the watthourmeter	741	(1)
27.10 Meter readout	742	(1)
27.11 Measuring three-phase energy and power	743	(1)
Questions and Problems	743	(3)
28. DIRECT-CURRENT TRANSMISSION	746	(22)
28.0 Introduction	746	(1)
28.1 Features of dc transmission	746	(1)
28.2 Basic dc transmission system	747	(1)
28.3 Voltage, current, and power relationships	748	(3)
28.4 Power fluctuations on a dc line	751	(1)
28.5 Typical rectifier and inverter characteristic	752	(1)
28.6 Power control	753	(1)
28.7 Effect of voltage fluctuations	754	(1)
28.8 Bipolar transmission line	754	(1)
28.9 Power reversal	755	(1)
28.10 Components of a dc transmission line	755	(1)
28.11 Inductors and harmonic filters on the dc side (6-pulse converter)	756	(1)
28.12 Converter transformers	756	(1)
28.13 Reactive power source	757	(1)
28.14 Harmonic filters on the ac side	757	(1)
28.15 Communications link	757	(1)
28.16 Ground electrode	757	(1)
28.17 Example of a monopolar converter station	757	(1)
28.18 Thyristor converter station	758	(2)
28.19 Typical installations	760	(5)
Questions and Problems	765	(3)
29. TRANSMISSION AND DISTRIBUTION SOLID-STATE CONTROLLERS	768	(31)
TRANSMISSION POWER FLOW CONTROLLERS
29.0 Introduction	768	(1)
29.1 Thyristor-controlled series capacitor (TCSC)	769	(2)
29.2 Vernier control	771	(2)
29.3 Static synchronous compensator	773	(3)
29.4 Eliminating the harmonics	776	(1)
29.5 Unified power flow controller (UPFC)	776	(4)
29.6 Static frequency changer	780	(2)
DISTRIBUTION CUSTOM POWER PRODUCTS
29.7 Disturbances on distribution systems	782	(2)
29.8 Why PWM converters?	784	(1)
29.9 Distribution system	785	(2)
29.10 Compensators and circuit analysis	787	(1)
29.11 The shunt compensator: principle of operation	787	(6)
29.12 The series compensator: principle of operation	793	(3)
29.13 Conclusion	796	(1)
Questions and Problems	797	(2)
30. HARMONICS	799	(32)
30.0 Introduction	799	(1)
30.1 Harmonics and phasor diagrams	799	(1)
30.2 Effective value of a distorted wave	800	(1)
30.3 Crest factor and total harmonic distortion (THD)	801	(1)
30.4 Harmonics and circuits	802	(2)
30.5 Displacement power factor and total power factor	804	(1)
30.6 Non-linear loads	804	(1)
30.7 Generating harmonics	805	(2)
30.8 Correcting the power factor	807	(1)
30.9 Generation of reactive power	808	(1)
EFFECT OF HARMONICS
30.10 Harmonic current in a capacitor	809	(1)
30.11 Harmonic currents in a conductor	810	(1)
30.12 Distorted voltage and flux in a coil	810	(2)
30.13 Harmonic currents in a 3-phase, 4-wire distribution system	812	(1)
30.14 Harmonics and resonance	813	(5)
30.15 Harmonic filters	818	(1)
30.16 Harmonics in the supply network	819	(2)
30.17 Transformers and the K factor	821	(2)
30.18 Procedure of analyzing a periodic wave	823	(4)
Questions and Problems	827	(4)
References	831	(6)
Appendix	837	(8)
AXO Conversion Charts	837	(4)
AX1 Properties of Insulating Materials	841	(1)
AX2 Electrical, Mechanical and Thermal Properties of Some Common Conductors (and Insulators)	842	(1)
AX3 Properties of Round Copper Conductors	843	(2)
Answers to Problems	845	(4)
Answers to Industrial Application Problems	849	(2)
Index	851