Power Systems

Daniel S. Kirschen is the Donald W. and Ruth Mary Close Professor of Electrical and Computer Engineering at the University of Washington, USA. Prior to joining the University of Washington, he taught for 16 years at The University of Manchester, UK. Before becoming an academic, he worked for Control Data and Siemens on the development of application software for utility control centers. He is a Fellow of the IEEE

• Preface xiiiNomenclature xvAbout the Companion Website xix1 Introduction 11.1 What is a Power System? 11.2 What are the Attributes of a Good Power System? 11.3 Structure of a Power System 21.3.1 Physical Structure 21.3.2 Cyber Infrastructure 41.3.3 Organizational Structure 51.4 Historical Evolution 5Problems 72 Electrical Loads and the Demand for Electricity 92.1 Overview 92.2 Residential Loads 92.3 Commercial and Industrial Loads 122.4 Load Aggregation over a Large Region 132.5 What Factors Shape the Aggregated Load Profile in the Short Run? 142.6 What Affects the Aggregated Electrical Load in the Long Run? 172.7 Metering and Billing 192.8 Flexibility 202.9 Outages 212.10 Complex Power, Reactive Power, and Power Factor 222.11 Parallel Loads 24Reference 27Further Reading 27Problems 273 Primary Energy Conversion 313.1 Overview 313.2 Wind Generation 313.2.1 How Much Power is There in the Wind? 313.2.2 How Does a Turbine Blade Extract Wind Power? 323.2.3 Controlling a Wind Turbine 333.2.4 Locating Wind Farms 343.2.5 Advantages and Disadvantages of Wind Generation 363.3 Thermal Generation 373.3.1 Concept of Heat Engine 373.3.2 Fossil-Fueled Steam Plants 383.3.3 Other Types of Steam Plants 393.3.3.1 Nuclear Power Plants 393.3.3.2 Concentrated Solar Power Plants 403.3.3.3 Geothermal Plants 403.3.3.4 Combined Heat and Power Plants – Cogeneration 403.3.4 Gas-Fired Generation 413.3.4.1 Open Cycle Gas Turbines (OCGT) 413.3.4.2 Combined Cycle Gas Turbines (CCGT) 413.3.5 Internal Combustion Engines 423.4 Hydroelectric Generation 423.4.1 Impoundment Hydro Plants 423.4.2 Diversion Hydro Plants 443.5 Photovoltaic Generation 443.6 Storage Systems 473.6.1 Pumped Hydro Plants 483.6.2 Electrochemical Batteries 483.6.3 Other Energy Storage Technologies 493.6.4 Applications of Energy Storage Systems 503.7 Choosing a Generation Technology 50Further Reading 52Problems 524 Electromechanical Power Conversion 574.1 Overview 574.2 Structure of a Generator 574.3 Three-Phase Systems 604.3.1 Advantages of Three-Phase Systems 604.3.2 Three-Phase Sources 604.3.3 Three-Phase Loads 634.3.3.1 Y-Connected Loads 644.3.3.2 Δ-Connected Loads 664.3.3.3 Δ-Y Equivalence 674.3.4 Powers in Three-Phase Systems 694.3.5 Single-Phase Representation and One-Line Diagrams 694.4 Per Unit System 704.4.1 Choosing Base Quantities in Single-Phase Systems 714.4.2 Choosing Base Quantities in Three-Phase Systems 714.4.3 Converting Per Unit Impedances 744.5 Synchronous Generator Model 754.6 Controlling an Isolated Synchronous Generator 764.7 Connecting a Generator to the Grid 774.8 Operating a Synchronized Generator 784.9 Synchronous Condenser 824.10 Generator Limits 82Further Reading 84Problems 855 Electronic Power Conversion 895.1 Overview 895.2 Switches 895.3 Voltage Source Converters 905.3.1 Single-Phase Voltage Source Converter 905.3.2 Converter Operation 925.3.3 Three-Phase Converter 945.4 Applications of Power Electronics in Power Systems 955.4.1 Battery Energy Storage 955.4.2 PV Generation 965.4.3 Type 4 Connection of a Wind Turbine 975.4.4 Type 3 Connection of a Wind Turbine 985.4.5 High-Voltage dc Links (HVDC) 100Further Reading 1016 Balancing Load and Generation 1036.1 Overview 1036.2 Power Balance 1036.3 Single Generator 1046.4 Multiple Generators 1066.5 Electronically Connected Generation and Battery Energy Storage 1086.6 Secondary Frequency Control 1096.7 System Response to Large Disturbances 1106.8 Economic Dispatch 1106.8.1 Heat Rate Curve and Cost Curve 1116.8.2 Mathematical Formulation 1126.8.3 Piecewise-Linear Cost Curves 1166.8.4 Load Flexibility and Storage 1186.9 Unit Commitment 1206.9.1 How Many Generating Units do we Need? 1206.9.2 Formulating the Unit Commitment Problem 1216.9.3 Solving the Unit Commitment Problem 1246.10 Handling of Uncertainty 126Reference 129Further Reading 129Problems 1297 Network Components 1357.1 Overview 1357.2 ac Lines 1357.3 dc Lines 1407.4 Transformers 1407.4.1 Single-Phase Transformer 1407.4.2 Three-Phase Transformer 1457.4.3 Transformer Ratings 1467.4.4 Three-Phase Transformers in the Per Unit System 1477.4.5 Tap-Changing Transformer 1487.4.6 Phase-Shifting Transformer 1527.5 Switchgear 1547.6 Reactive Compensation Devices 1547.7 Substations 155Further Reading 156Problems 1568 Power Flow 1638.1 Overview 1638.2 Qualitative Relation Between Flows and Voltages 1638.3 Nodal Analysis 1658.3.1 An Example of Nodal Analysis 1658.4 Formulation of the Power Flow Problem 1698.5 Solving the Power Flow Equations 1728.5.1 Newton–Raphson Method 1728.5.2 Applying the Newton–Raphson Method to the Power Flow Problem 1758.6 Calculating the Line Flows 1808.7 Power Flow Applications 1818.8 Optimal Power Flow 188Further Reading 189Problems 1899 Analysis of Balanced Faults 1979.1 Overview 1979.2 Two Simple Examples 1989.3 Balanced Fault Calculations in Large Systems 2019.4 Modeling Generators for Fault Calculations 2059.5 Inverter-Based Generation 210Reference 210Further Reading 210Problems 21110 Analysis of Unbalanced Faults 21510.1 Overview 21510.2 Symmetrical Components 21510.2.1 Notation 21510.2.2 Concept of Symmetrical Components 21610.2.3 Calculating the Sequence Components 21610.2.4 Relation Between the Neutral and Zero-sequence Currents 21910.3 Sequence Networks 22010.3.1 Sequence Networks Representation of Impedance Loads 22010.3.2 Sequence Networks Representation of Generators 22510.3.3 Sequence Networks Representation of Three-phase Lines and Cables 22610.3.4 Sequence Networks Representation of Three-phase Transformers 22610.3.5 Sequence Networks Representation of Power Systems 22810.4 Unbalanced Faults 23010.4.1 Balanced Three-phase Fault 23110.4.2 Single Line-to-ground Fault 23210.4.3 Line-to-line Fault 23410.4.4 Double Line-to-ground Fault 23510.5 Unbalanced Fault Calculations in Large Systems 237References 240Further Reading 240Problems 24011 Introduction to Power System Stability 24511.1 Overview 24511.2 P–V Curves 24511.3 Effect of Outages 24811.4 Cascading Overloads 24911.5 Electromechanical or Transient Stability 25211.5.1 Modeling the Mechanical Dynamics of Synchronous Generators: the Swing Equation 25311.5.2 Modeling the Electrical Dynamics of Synchronous Generators 25611.5.3 A Simple Model of the Rest of the System 25711.5.4 Stable and Unstable Operating Points 25711.5.5 Large Disturbances 25911.5.6 Equal Area Criterion 26111.5.7 Factors Influencing Stability 26611.5.8 Transient Stability Analysis Using Time Domain Simulation 26711.5.9 Simulating the Dynamics of Multi-generator Systems 27011.5.10 Damping 27711.6 Detailed Dynamic Models 27911.7 Power System Oscillations 27911.8 Preventing Instabilities 279Further Reading 280Problems 28112 Introduction to Competitive Electricity Markets 28712.1 Overview: Why Competition? 28712.2 Fundamentals of Markets 28712.3 Wholesale Electricity Markets 29112.4 Bidding in a Centralized Market 29412.5 Variation of Market Price with Time 29412.6 Effect of Transmission Capacity Limits 29712.7 Two-Settlement Markets 29912.8 Ancillary Services 30012.9 Retail Markets 30112.10 Unbundled Industry Structure 301Further Reading 303Problems 303Index 307