Synchronous Generators

3. Auflage 2027
ISBN: 978-1-041-21536-3
Verlag: Taylor & Francis

Buch, Englisch, 656 Seiten, Format (B × H): 156 mm x 234 mm

The subject of Electric Generators (“Synchronous Generators” and” Variable Speed Generators” as in book here) attracted formidable R&D effort, both in Academia and in various industries in the last decade. To the point that “Electric generators design, testing and control” – the subject of present book set, may constitute a new senior or graduate Course in Universities with electric power programs and a practical guide for young professionals in industry. In the last 10 years design and control of electric generators for applications in energy conversion, through transport electrification, e-buildings, industrial processes, auxiliary power sources, inspired a rich body of new knowledge. By now, only the wind energy industry has more than 1000 GW of installed power (in 2025). In view of this progress, we decided (after 10 years) to come with a new (third) edition of this two-set book that:

- Keeps the structure of the second edition to avoid confusion to long-term users.

- Keeps and adds to the style with more numerical work-out examples of practical interest, together with more case studies to inspire the new R&D reader.

- Includes additional (though minor) needed text and number corrections.

- Adds quite a few new paragraphs, in most existing Chapters, especially as case studies of design or control of new (recent) electric generator systems of hot industrial interest.

Zielgruppe

General

Autoren/Hrsg.

Boldea, Ion

Inhaltsverzeichnis

1 Electric Energy and Electric Generators
1.1 Introduction.1
1.2 Major Energy Sources.3
1.3 Electric Power Generation Limitations.4
1.4 Electric Power Generation.4
1.5 From Electric Generators to Electric Loads.7
1.6 Summary.12
References ………………………………………………………………………………………………… 12
2 Principles of Electric Generators
2.1 Three Types of Electric Generators.13
2.2 Synchronous Generators.15
2.3 Permanent Magnet Synchronous Generators. 20
2.4 Homopolar Synchronous Generator. 23
2.5 Induction Generator. 25
2.6 Wound-Rotor (DFIG) Doubly-Fed Induction Generator.28
2.7 Parametric Generators.30
2.7.1 Flux Reversal Generators. 32
2.7.2 Transverse Flux Generators.34
2.7.3 Linear Motion Alternators. 34
2.8 Electric Generator Applications. 39
2.9 High-Power Wind Generators. …39
2.9.1 Introduction ……………………………………………………………………….………………… 39
2.9.2 DC Excited Synchronous Generator Systems. 45
2.9.2.1 Brushless Excitation. 45
2.9.2.2 Lower Size (Weight) by Optimal Design.46
2.9.2.3 DD Superconducting Synchronous Generators. 47
2.9.2.4 Claw Pole 1G-dceSG (3 MW, 75 rpm).48
2.9.2.5 Windformer. 50
2.9.3 Less-PM PMSGs …………………………………………………………………………………….…………………….…50
2.9.3.1 Ferrite TF-PMSG with Axial Air Gap.51
2.9.3.2 High Speed Modular PMSG (4 × 0.75 MW, 4000 rpm). 52
2.9.3.3 Flux Reversal PMSGs. 53
2.9.3.4 The Vernier Machine. 54
2.9.4 Multiple Phase Reluctance Generators (BLDC-MRG). 55
2.9.5 DFIG: Brushless?.57
2.9.6 Brushless Doubly Fed Reluctance (or Induction) Generators.59
2.9.7 Switched Reluctance Generators Systems.61
2.9.7.1 DD-SRG.61
2.9.7.2 High Speed Wind SRG. 62
2.9.8 Flux-Switch Ferrite PM Stator Generators. 63
2.10 Summary.66
References ………………………………………………………………………………………………….66
3 Prime Movers
3.1 Introduction.71
3.2 Steam Turbines.73
3.3 Steam Turbine Modeling. 75
3.4 Speed Governors for Steam Turbines.79
3.5 Gas Turbines.81
3.6 Diesel Engines. 83
3.6.1 Diesel Engine Operation. 83
3.6.2 Diesel Engine Modeling. …………….85
3.7 Stirling Engines.87
3.7.1 Summary of Thermodynamic Basic Cycles.87
3.7.2 Stirling-Cycle Engine.90
3.7.3 Free-Piston Linear-Motion Stirling Engines Modeling.91
3.8 Hydraulic Turbines.94
3.8.1 Hydraulic Turbines Basics. 95
3.8.2 First-Order Ideal Model for Hydraulic Turbines. 98
3.8.3 Second and Higher Order Models of Hydraulic Turbines. 101
3.8.4 Hydraulic Turbine Governors.104
3.8.5 Reversible Hydraulic Machines.106
3.9 Wind Turbines.109
3.9.1 Principles and Efficiency of Wind Turbines.111
3.9.2 Steady-State Model of Wind Turbines.114
3.9.3 Wind Turbine Models for Control.118
3.9.3.1 Unsteady Inflow Phenomena in Wind Turbines.119
3.9.3.2 Pitch-Servo and Turbine Model.119
3.10 New, advanced pitch control of wind turbines: a review
3.11 Summary.121
References ……………………………………………………………………………………………….…123
4 Large and Medium Power Synchronous Generators: Topologies and
Steady State
4.1 Introduction.125
4.2 Construction Elements.125
4.2.1 Stator Windings ……………………………………………………………………………………….127
4.3 Excitation Magnetic Field.132
4.4 Two-Reaction Principle of Synchronous Generators.136
4.5 Armature Reaction Field and Synchronous Reactances.138
4.6 Equations for Steady State with Balanced Load.142
4.7 Phasor Diagram.144
4.8 Inclusion of Core Losses in the Steady-State Model.145
4.9 Autonomous Operation of Synchronous Generators.150
4.9.1 No Load Saturation Curve: E1(If); n = ct, I1 = 0.150
4.9.2 Short Circuit Saturation Curve I1 = f(If); V1 = 0, n1 = nr = ct.156
4.9.3 Zero Power Factor Saturation Curve V1(IF); I1 = ct, cos f1 = 0, n1 = nr.158
4.9.4 V1–I1 Characteristic, IF = ct, cos f1 = ct, n1 = nr.159
4.10 SG Operation at Power Grid (in Parallel).160
4.10.1 Power/Angle Characteristic: Pe (dV).………….……161
4.10.2 V-Shape Curves: I1(IF), P1 = ct, V1 = ct, n = ct.163
4.10.3 Reactive Power Capability Curves.164
4.10.4 Defining Static and Dynamic Stability of SGs.165
4.11 Unbalanced Load Steady-State Operation.168
4.12 Measuring Xd, Xq, Z-, Z0.170
4.13 Phase-to-Phase Short Circuit.172
4.14 Synchronous Condenser.177
4.15 PM-Assisted DC Excited Salient Pole Synchronous Generators.178
4.16 Multiphase Synchronous Machine Inductances via Winding Function Method. 181
4.17 Contactless power transfer to SG rotors: inductive and capacitive
4.18 Summary.183
References…………………………………………………………………………………………………. 185
5 Synchronous Generators: Modeling for Transients
5.1 Introduction.187
5.2 Phase-Variable Model.188
5.3 d–q Model.193
5.4 Per Unit (P.U.) dq Model.201
5.5 Steady State via the d–q Model.203
5.6 General Equivalent Circuits.207
5.7 Magnetic Saturation Inclusion in the d–q Model.209
5.7.1 The Single d–q Magnetization Curves Model.209
5.7.2 Multiple d–q Magnetization Curves Model.213
5.8 Operational Parameters.214
5.8.1 Electromagnetic Transients.216
5.8.2 Sudden Three-Phase Short Circuit from No Load.218
5.9 Standstill Time Domain Response Provoked Transients.222
5.10 Standstill Frequency Response.226
5.10.1 Asynchronous Running.227
5.11 Simplified Models for Power System Studies.233
5.11.1 Neglecting the Stator Flux Transients.233
5.11.2 Neglecting the Stator Transients and the Rotor Damper Winding Effects.234
5.11.3 Neglecting All Electrical Transients.234
5.12 Mechanical Transients.235
5.12.1 Response to Step Shaft Torque Input.236
5.12.2 Forced Oscillations.236
5.13 Small Disturbance Electromechanical Transients.239
5.14 Large Disturbance Transients Modeling.242
5.14.1 Line to Line Fault.245
5.14.2 Line to Neutral Fault.246
5.15 Finite Element SG Modeling.246
5.16 SG Transient Modeling for Control Design.249
5.17 Summary.251
References …………………………………………………………………………………………………….255
6 Control of Synchronous Generators in Power Systems
6.1 Introduction.……….257
6.2 Speed Governing Basics.259
6.3 Time Response of Speed Governors.………….263
6.4 Automatic Generation Control.……….….265
6.5 Time Response of Speed (Frequency) and Power Angle.………….267
6.6 Voltage and Reactive Power Control Basics.270
6.7 Automatic Voltage Regulation Concept.271
6.8 Exciters ……………………………………………………………………………….………………….272
6.8.1 AC Exciters …………………………………………………………………………………………….273
6.8.2 Static Exciters ………………………………………………………………………………………….274
6.9 Exciter’s Modeling.275
6.9.1 New PU System …………………………………………………………………………………………276
6.9.2 DC Exciter Model.277
6.9.3 AC Exciter ………………………………………………………………………………………………280
6.9.4 Static Exciter ……………………………………………………………………………………….….282
6.10 Basic AVRs.283
6.11 Underexcitation Voltage.287
6.12 Power System Stabilizers.288
6.13 Coordinated AVR-PSS and Speed Governor Control.291
6.14 FACTS-Added Control of SG. ……….292
6.14.1 Series Compensators.296
6.14.2 Phase-Angle Regulation and Unit Power Flow Control.297
6.15 Subsynchronous Oscillations.298
6.15.1 Multi-Mass Shaft Model.298
6.15.2 Torsional Natural Frequency.300
6.16 Subsynchronous Resonance.301
6.17 Note on Autonomous Synchronous Generators’ Control.302
6.17.1 Variable Frequency/Speed SG with Brushless Exciter.303
6.18 Aircraft brushless d.c. excited starter/generator systems: recent progress
6.19 Full size converter operation of SG/m in large pump storage systems

6.20 Summary
References
7 Design of Synchronous Generators
7.1 Introduction.313
7.2 Specifying Synchronous Generators for Power Systems.313
7.2.1 Short Circuit Ratio.314
7.2.2 SCR and xd' Impact on Transient Stability.314
7.2.3 Reactive Power Capability and Rated Power Factor.315
7.2.4 Excitation Systems and Their Ceiling Voltage.316
7.2.4.1 Voltage and Frequency Variation Control.316
7.2.4.2 Negative Phase Sequence Voltage and Currents.317
7.2.4.3 Harmonic Distribution.317
7.2.4.4 Temperature Basis for Rating.318
7.2.4.5 Ambient: Following Machines.318
7.2.4.6 Reactances and Unusual Requirements.318
7.2.4.7 Start–Stop Cycles.319
7.2.4.8 Starting and Operation as a Motor.319
7.2.4.9 Faulty Synchronization. 320
7.2.4.10 Forces ……………………………………………………………………………………….320
7.2.4.11 Armature Voltage. 320
7.2.4.12 Runaway Speed.321
7.2.4.13 Design Issues.321
7.3 Output Power Coefficient and Basic Stator Geometry.321
7.4 Number of Stator Slots.325
7.5 Design of Stator Winding.328
7.6 Design of Stator Core.333
7.6.1 Stator Stack Geometry.335
7.7 Salient: Pole Rotor Design.339
7.8 Damper Cage Design.343
7.9 Design of Cylindrical Rotors.344
7.10 Open Circuit Saturation Curve.348
7.11 On-Load Excitation m.m.f. F1n.353
7.11.1 Potier Diagram Method.354
7.11.2 Partial Magnetization Curve Method.355
7.12 Inductances and Resistances.359
7.12.1 Magnetization Inductances Lad, Laq.359
7.12.2 Stator Leakage Inductance Lsl.360
7.13 Excitation Winding Inductances.362
7.14 Damper Winding Parameters.364
7.15 Solid Rotor Parameters.365
7.16 SG Transient Parameters and Time Constants.367
7.16.1 Homopolar Reactance and Resistance.368
7.17 Electromagnetic Field Time Harmonics.370
7.18 Slot Ripple Time Harmonics.372
7.19 Losses and Efficiency.373
7.19.1 No Load Core Losses of Excited SGs. ………374
7.19.2 No Load Losses in the Stator Core End Stacks. ……….376
7.19.3 Short Circuit Losses. 377
7.19.4 Third Flux Harmonic Stator Teeth Losses. ……….379
7.19.5 No Load and On Load Solid Rotor Surface Losses. 380
7.19.6 Excitation Losses. ………383
7.19.7 Mechanical Losses. ………383
7.19.8 SG Efficiency …………………………………………………………………………………. 385
7.20 Exciter Design Issues. 386
7.20.1 Excitation Rating. 388
7.20.2 Sizing the Exciter. 388
7.20.3 Note on Thermal and Mechanical Design.389
7.21 Optimization Design Issues.389
7.21.1 Optimal Design of a Large Wind Generator by Hooke–Jeeves Method.391
7.21.2 Magnetic Equivalent Circuit (MEC) Population–Based Optimal Design of SG.392
7.22 Generator/Motor Issues. 394
7.23 ALA rotor RSG of 10 MW, 480 rpm: preliminary design with key FEM validations: a case study
7.24 Summary

8 Testing of Synchronous Generators
8.1 Acceptance Testing.405
8.1.1 A1. Insulation Resistance Testing.406
8.1.2 A2. Dielectric and Partial Discharge Tests.406
8.1.3 A3. Resistance Measurement.406
8.1.4 A4–5. Tests for Short-Circuited Field Turns and Polarity.406
8.1.5 A6. Shaft Current and Bearing Insulation.407
8.1.6 A7. Phase Sequence.407
8.1.7 A8. Telephone Influence Factor (TIF).408
8.1.8 A9. Balanced Telephone-Influence Factor.408
8.1.9 A10. Residual-Component Telephone-Influence Factor.408
8.1.10 A11. Line to Neutral Telephone Influence Factor.408
8.1.11 A12. Stator Terminal Voltage Waveform Deviation and Distortion Factor.409
8.1.12 A12. Over-Speed Tests.410
8.1.13 A13. Line Charging.410
8.1.14 A14. Acoustic Noise. 411
8.2 Testing for Performance (Saturation Curves, Segregated Losses, and Efficiency). 411
8.2.1 Separate-Driving for Saturation Curves and Losses. 411
8.2.2 Electric Input (Idle-Motoring) Method for Saturation Curves and Losses.414
8.2.3 Retardation (Free Deceleration Tests).417
8.3 Excitation Current under Load and Voltage Regulation.418
8.3.1 The Armature Leakage Reactance.419
8.3.2 Potier Reactance ……………………………………………………………………………….420
8.3.3 Excitation Current for Specified Load.421
8.3.4 Excitation Current for Stability Studies.422
8.3.5 Temperature Tests. 423
8.3.5.1 Conventional Loading. 423
8.3.5.2 Synchronous Feedback (Back to Back) Loading Testing. 423
8.3.5.3 Zero Power Factor Load Test.424
8.4 Need for Determining Electrical Parameters. 425
8.5 Per Unit Values.426
8.6 Tests for Parameters under Steady State.428
8.6.1 Xdu, Xds Measurements.429
8.6.2 Quadrature-Axis Magnetic Saturation Xq from Slip Tests.429
8.6.2.1 Slip Test ………………………………………………………………………………………430
8.6.2.2 Quadrature Axis (Reactance) Xq from Maximum Lagging Current Test.430
8.6.3 Negative Sequence Impedance Z2.431
8.6.4 Zero Sequence Impedance Zo. 433
8.6.5 Short Circuit Ratio.434
8.6.6 Angle d, Xds, Xqs Determination from Load Tests.435
8.6.7 Saturated Steady-State Parameters from Standstill Flux Decay Tests.436
8.7 Tests to Estimate the Subtransient and Transient Parameters.440
8.7.1 Three Phase Sudden Short Circuit Tests.440
8.7.2 Field Sudden Short Circuit Tests with Open Stator Circuit.441
8.7.3 The Short Circuit Armature Time Constant Ta.442
8.8 Transient and Subtransient Parameters from d and q Axis Flux Decay Test

at Standstill ………………………………………………………………………….……………….444
8.9 Subtransient Reactances from Standstill Single Frequency ac Tests.445
8.10 Standstill Frequency Response Tests (SSFR).446
8.10.1 Background ……………………………………………………………………………………446
8.10.2 From SSFR Measurements to Time Constants. 452
8.10.3 The SSFR Phase Method. 452
8.11 Online Identification of SG Parameters.454
8.11.1 A Small Signal Injection on: Line Technique. 455
8.11.2 Line Switching (On or Off) Parameter Identification for Isolated Grids. …………….457
8.11.3 Synthetic Back to Back Load Testing with Inverter Supply. ………….458
8.12 Pole drop test, renewed: a case study
8.13 Emulation of IEEE STD 421.5/industrial excitation systems using a micro-
alternator’s exciter – a case study.
8.14 High frequency response analysis (HFRA) to diagnose ground and interturn faults in

salient pole large generators.

8.15 Summary
References
Index

Über Autor(innen)

Prof. Ion Boldea (IEEE Life Fellow) studied at and obtained a PhD in Electrical Engineering (on linear induction motors design and control) in 1973 at University Politehnica Timisoara, Romania. He has been an active professor since 1968, having completed a Fulbright postdoctoral scholarship in the United States (1973-1974). Over the years, he has spent more than five years as a visiting Professor at institutions across the United States, the United Kingdom, Denmark, and South Korea.

He investigated and published extensively on linear and rotary electric machine drives and magnetically levitated vehicles (MAGLEVs), focusing on their design and control for industrial applications, with his work appearing primarily in IEEE papers and books.

In recognition of his professional contribution, he received the 2015 Nikola Tesla IEEE Award and 2021 EPE Outstanding Achievement Award. He is a full member of both the Romanian Technical Sciences Academy (ASTR) and the Romanian Academy, and holds a Doctor Honoris Causa from Aalborg University, Denmark.

Prof. Boldea has given numerous keynote addresses at IEEE – sponsored international conferences and has delivered (as an IEEE-IAS Distinguished Lecturer since 2008) numerous intensive courses and lectures in the United States, Denmark, South Korea, Brazil and Italy, among other countries. He chaired and co-chaired the biannual IEEE Sponsored International Conference, OPTIM-ACEMP, for over 30 years. He has also held tech consulting contracts with international companies for decades, yearly and co-founded the company Bee-Speed (www.Bee-Speed.ro) in 1994, which is still continually active today, specializing in industrial digital electric automation in water integrated technologies.

He enjoys a rich family life and studies seminal books in philosophy, literature, economics, math and physics. He rides his bicycle to work daily, and his hobbies include gardening and tennis.