Distributed Generation

Loi Lei Lai graduated from Aston University in Birmingham with a BSc and a PhD. He was awarded a DSc by City University London. He is also an honrorary graduate of City University. In 1984, he was appointed Senior Lecturer at Staffordshire Polytechnic. From 1986 to 1987, he was a Royal Academy of Engineering Industrial Fellow to both GEC Alsthom Turbine Generators Ltd and the Engineering research Centre. He is currently Head of Energy Systems Group and Chair in Electrical Engineering at City University London. In the last decade, Professor Lai has authored/co-authored 200 technical publications. He has also written a book entitled Intelligent System Applications in Power Engineering - Evolutionary Programming and Neural Networks and, in 2001, edited the book Power System Restructuring and Deregulation - Trading, Performance and Information Technology, both published by John Wiley & Sons, Ltd. He was award the IEEE Third Millennium Medal and won the IEEE Power Engineering Society, United Kingdom and Republic of Ireland (UKRI), chapter, Outstanding Engineer Award in 2003. In 1995, he received a high-quality paper prize from the International Association of Desalination, USA and in 2006 he was awarded a Prize paper by the IEEE Power Generation Committee. He is a Fellow of the IEEE and the IET (Institution of Engineering and Technology). Among his professional activities, he is a Founder and was the Conference Chairman of the international Conference on Power Utility Deregulation, Restructuring man of the International Conference on Power Utility Deregulation, Restructuring and Power Technologies (DRPT) 2000, co-sponsored by the IEEE (now IET) and Power Technologies (DRPT) 2000, co-sponsored by the IEE (now IET) and IEEE. He reviews grant proposals regularly for the EPSRC, Australian Research Council and Hong Kong research Grant Council. In 2001, he was invited by the Hong Kong Institution of Engineers to be Chairman of an Accreditation Visit Team to accredit the BEng (Hons) degree in Electrical Engineering. Since 2005, Professor Lai has been invited as a judge for the Power/Energy Category in the IET Innovation in Engineering Awards. He was also Student Recruitment Office of the IEEE UKRI Section Executive Committee. He is a member of the Intelligent Systems Subcommittee in Power System Analysis, Computing and Economic Committee, IEEE Power Engineering Society; a Member of the Executive Team of the Power Trading and Control Technical and Professional Network, IET; an Editor of the IEE Proceedings - Generation, Distribution and Generation (now IET Generation, Distribution and Generation); an Editorial Board Member of the International Journal of Electrical Power & Energy Systems published by Elsevier Science Ltd, UK; International Advisor, Hong Kong Institution of Engineers (HKIE) Transactions and an Editorial Board Member of the European Transactions on Electrical Power published by John Wiley & Sons, Ltd. He was a research Professor at Tokyo Metropolitan University, is also Visiting professor at Southeast University Nanjing and Guest Professor at Fudan University, Shanghai. He has also been invited to deliver keynote addresses and plenary speeches to several major international conferences sponsored by the IET and IEEE.Tze Fun Chan received his BSc (Eng) and MPhil degrees in electrical engineering from the University of Hong Kong in 1974and 1980, respectively. He received his PhD in electrical engineering from City University London in 2005. Currently, Dr Chan is an Associate Professor in the Department of Electrical Engineering, Hong Kong Polytechnic University, where he has been since 1978. His research interests are self-excited AC generators, brushless AC generators and permanent magnet machines. In June 2006, he was awarded a Prize Paper by the IEEE Power Engineering Society Energy Development and Power Generation Committee.

• Foreword xiPreface xiiiAcknowledgements xviiAbout the Authors xix1 Distributed Generation 11.1 Introduction 11.2 Reasons for DG 11.3 Technical Impacts of DG 31.3.1 DG Technologies 31.3.2 Thermal Issues 51.3.3 Voltage Profile Issues 51.3.4 Fault-Level Contributions 71.3.5 Harmonics and Interactions with Loads 71.3.6 Interactions Between Generating Units 81.3.7 Protection Issues 81.4 Economic Impact of DG 91.5 Barriers to DG Development 101.6 Renewable Sources of Energy 111.7 Renewable Energy Economics 121.8 Interconnection 151.8.1 Interconnection Standardization 151.8.2 Rate Design 151.9 Recommendations and Guidelines for DG Planning 161.10 Summary 182 Generators 212.1 Introduction 212.2 Synchronous Generator 212.2.1 Permanent Magnet Materials 222.2.2 Permanent Magnet Generator 232.3 Induction Generator 282.3.1 Three-Phase IGs and SEIGs 292.3.2 Single-Phase IGs and SEIGs 302.4 Doubly Fed Induction Generator 312.4.1 Operation 312.4.2 Recent Work 332.5 Summary 343 Three-Phase IG Operating on a Single-Phase Power System 413.1 Introduction 413.2 Phase Balancing using Passive Circuit Elements 413.2.1 Analysis of IG with Phase Converters 413.2.2 Phase Balancing Schemes 433.2.3 Case Study 453.2.4 System Power Factor 473.2.5 Power and Efficiency 493.2.6 Operation with Fixed Phase Converters 503.2.7 Summary 513.3 Phase Balancing using the Smith Connection 523.3.1 Three-Phase IG with the Smith Connection 523.3.2 Performance Analysis 543.3.3 Balanced Operation 553.3.4 Case Study 583.3.5 Effect of Phase Balancing Capacitances 613.3.6 Dual-Mode Operation 653.3.7 Summary 663.4 Microcontroller-Based Multi-Mode Control of SMIG 673.4.1 Phase Voltage Consideration 673.4.2 Control System 673.4.3 Practical Implementation 713.4.4 Experimental Results 723.4.5 Summary 753.5 Phase Balancing using a Line Current Injection Method 773.5.1 Circuit Connection and Operating Principle 773.5.2 Performance Analysis 783.5.3 Balanced Operation 803.5.4 Case Study 823.5.5 Summary 914 Finite Element Analysis of Grid-Connected IG with the Steinmetz Connection 934.1 Introduction 934.2 Steinmetz Connection and Symmetrical Components Analysis 944.3 Machine Model 954.4 Finite Element Analysis 964.4.1 Basic Field Equations 964.4.2 Stator Circuit Equations 974.4.3 Stator EMFs 994.4.4 Rotor Circuit Model 994.4.5 Comments on the Proposed Method 1024.5 Computational Aspects 1034.6 Case Study 1044.7 Summary 1095 SEIGs for Autonomous Power Systems 1115.1 Introduction 1115.2 Three-Phase SEIG with the Steinmetz Connection 1115.2.1 Circuit Connection and Analysis 1115.2.2 Solution Technique 1145.2.3 Capacitance Requirement 1155.2.4 Computed and Experimental Results 1175.2.5 Capacitance Requirement on Load 1215.2.6 Summary 1235.3 SEIG with Asymmetrically Connected Impedances and Excitation Capacitances 1235.3.1 Circuit Model 1245.3.2 Performance Analysis 1245.3.3 Computed and Experimental Results 1255.3.4 Modified Steinmetz Connection 1265.3.5 Simplified Steinmetz Connection 1335.3.6 Summary 1355.4 Self-regulated SEIG for Single-Phase Loads 1365.4.1 Circuit Connection and Analysis 1365.4.2 Effect of Series Compensation Capacitance 1385.4.3 Experimental Results and Discussion 1435.4.4 Effect of Load Power Factor 1475.4.5 Summary 1495.5 SEIG with the Smith Connection 1505.5.1 Circuit Connection and Operating Principle 1505.5.2 Performance Analysis 1515.5.3 Balanced Operation 1525.5.4 Results and Discussion 1535.5.5 Summary 1596 Voltage and Frequency Control of SEIG with Slip-Ring Rotor 1616.1 Introduction 1616.2 Performance Analysis of SESRIG 1626.3 Frequency and Voltage Control 1656.4 Control with Variable Stator Load 1666.5 Practical Implementation 1686.5.1 Chopper-Controlled Rotor External Resistance 1686.5.2 Closed-Loop Control 1696.5.3 Tuning of PI Controller 1706.5.4 Dynamic Response 1706.6 Summary 1737 PMSGs For Autonomous Power Systems 1757.1 Introduction 1757.2 Principle and Construction of PMSG with Inset Rotor 1757.3 Analysis for Unity-Power-Factor Loads 1777.3.1 Analysis Using the Two-Axis Model 1777.3.2 Design Considerations 1807.3.3 Computed Results 1827.3.4 Experimental Results 1837.3.5 Summary 1847.4 A Comprehensive Analysis 1857.4.1 Basic Equations and Analysis 1857.4.2 Conditions for Zero Voltage Regulation 1887.4.3 Extremum Points in the Load Characteristic 1907.4.4 Power–Load Angle Relationship 1917.4.5 The Saturated Two-Axis Model 1927.4.6 Summary 1947.5 Computation of Synchronous Reactances 1947.5.1 Analysis Based on FEM 1947.5.2 Computation of Xd and Xq 1967.5.3 Computed Results 1977.5.4 Summary 2017.6 Analysis using Time-Stepping 2-D FEM 2017.6.1 Machine Model and Assumptions 2017.6.2 Coupled Circuit and Field Analysis 2027.6.3 Magnetic Saturation Consideration 2057.6.4 Computed Results 2077.6.5 Experimental Verification 2117.6.6 Summary 2128 Conclusions 2158.1 Accomplishments of the Book 2158.2 Future Work 217AppendixA Analysis for IG and SEIG 219A.1 Symmetrical Components Equations for IG 219A.2 Positive-Sequence and Negative-Sequence Circuits of IG 220A.3 Vp and Vn for IG with Dual-Phase Converters 221A.4 Derivation of Angular Relationship 223A.5 Input Impedance of SEIG with the Steinmetz Connection 224Appendix B The Method of Hooke and Jeeves 227AppendixC A Note on the Finite Element Method [1] 229C.1 Energy Functional and Discretization 229C.2 Shape Functions 230C.3 Functional Minimization and Global Assembly 233Reference 234AppendixD Technical Data of Experimental Machines 235D.1 Machine IG1 235D.2 Machine IG2 236D.3 Prototype PMSG with Inset Rotor 236Index 239