A practical and systematic guide to the analysis, design and control of grid–integrated and standalone distributed photovoltaic (PV) generation systems
Grid–Integrated and Standalone Photovoltaic Distributed Generation Systems contains a comprehensive and systematic examination of the theory and applications of key technologies in the analysis, design, and control of grid–integrated and standalone distributed photovoltaic (PV) generation systems. Comprehensive in scope, treatment includes an overview of the current status and future development trend of PV generation, the principles of PV generation and other distributed generation (DG) technologies, and analysis of distribution networks with PV generation sources including penetration assessment, load characteristic analysis, power flow study and reactive voltage regulation, and much more.
The authors explore techniques for accommodating intermittent output of PV generation and offer an analysis and design of standalone microgrids with PV generation sources. Issues of power and energy management of microgrids with multiple distributed energy resources (DER), including PV and energy storage, are discussed. Combined with real–world project examples, this important work:
- Offers an analysis of distribution networks with high penetration of PV systems and standalone microgrids with PV systems
- Covers in detail PV accommodation techniques including energy storage, demand side management and PV output power regulation
- Features examples of real projects/systems given in OPENDSS codes and/or Matlab and Simulink models
- Provides a concise summary of up–to–date research around the world in distributed PV systems
Written for researchers, engineers and operators and other professionals, Grid–Integrated and Standalone Photovoltaic Distributed Generation Systems is a vital resource for understanding the theory and application of the recent technologies.
Table of Contents
Preface xiii
1 Overview 1
1.1 Current Status and Future Development Trends of Photovoltaic Generation around theWorld 1
1.1.1 USA 3
1.1.2 Japan 5
1.1.3 Germany 5
1.1.4 China 6
1.2 Current Research Status of Grid–Connected Photovoltaic Generation 8
1.2.1 Characteristics of Grid–Connected Photovoltaic Generation 8
1.2.2 Impact of High–Penetration Photovoltaic Generations on Distribution Networks 9
1.2.3 Research Needs on Massive Distributed Grid–Connected Photovoltaic Generation 11
1.3 Summary 13
References 14
2 Techniques of Distributed Photovoltaic Generation 17
2.1 Introduction to Distributed Photovoltaic Generation 17
2.1.1 Distributed Generation: Definition and Advantages 17
2.1.2 Principle and Structure of Distributed Photovoltaic Generation 18
2.2 Photovoltaic Cells 20
2.2.1 Classification of the Photovoltaic Cells 20
2.2.1.1 Classification Based on Cell Structure 20
2.2.1.2 Material–based PV Cell Classification 21
2.2.2 Development History of Solar Cells 21
2.2.3 Model of a Silicon Solar Cell 22
2.3 Inverter 26
2.3.1 Topology of Connection between Inverter and Photovoltaic Module 26
2.3.2 The Classification and Characteristics of the Inverter 28
2.3.3 Requirements of a Grid–Connected Photovoltaic Inverter 29
2.4 Maximum Power Point Tracking Control 32
2.4.1 Hill Climbing/Perturb and Observe 33
2.4.2 Incremental Conductance 34
2.4.3 Open–Circuit Voltage Method 36
2.4.4 Short–Circuit Current Method 36
2.4.5 Ripple Correlation Control 36
2.4.6 Load Current or Load Voltage MaximizationMethod 37
2.4.7 dP/dV or dP/dI Close–Loop Control 38
2.4.8 Maximum Power Point Tracking Efficiency 38
2.5 Summary 39
References 40
3 Load Characteristics in Distribution Networks with Distributed Photovoltaic Generation 43
3.1 Introduction 43
3.2 Load Characteristics of a Distribution Network 43
3.2.1 Load Types and Indices 43
3.2.2 Time–Sequence Characteristics of Typical Loads 45
3.2.3 Case Study 46
3.3 The Output Characteristics of Photovoltaic Generation 48
3.3.1 Regulations on Grid–Connected Photovoltaic Generation 48
3.3.2 Time–Sequence Characteristics of Photovoltaic Generation 49
3.3.3 Case Study 51
3.4 Characteristics of the Net Load in a Distribution Network with Distributed Photovoltaic Generation 53
3.4.1 Influence of Distributed Photovoltaic Generation on System Load Level 54
3.4.2 Influences of Distributed Photovoltaic Generation on Load Fluctuation 56
3.5 Power and Energy Analysis of Distributed Photovoltaic Generation 57
3.5.1 Effective Power and Equivalent Electricity Generation of Distributed Photovoltaic Generation 57
3.5.2 CalculationMethods of the Correction Coefficients 58
3.6 Summary 61
References 62
4 Penetration Analysis of Large–Scale Distributed Grid–Connected Photovoltaics 65
4.1 Introduction 65
4.2 Economic Analysis of Distributed Photovoltaic Systems 66
4.2.1 Cost/Benefit Analysis of Distributed Grid–Connected Photovoltaic Systems 66
4.2.1.1 Cost Composition 66
4.2.1.2 Income Composition 67
4.2.2 Grid Parity 68
4.3 Large–Scale Photovoltaic Penetration Analysis 70
4.3.1 Further Explanation of Some Concepts 70
4.3.2 Concepts and Assumptions 71
4.3.2.1 Basic Concepts 71
4.3.2.2 Basic Assumptions 73
4.3.3 Power Penetration Analysis 73
4.3.4 Photovoltaics Penetration with Different Types of Load 79
4.4 Maximum Allowable Capacity of Distributed Photovoltaics in Distribution Network 82
4.4.1 Static Characteristic Constraint Method 82
4.4.1.1 Voltage Constraint 83
4.4.1.2 Protection 83
4.4.1.3 Harmonic Limit 85
4.4.2 Constrained OptimizationMethod 86
4.4.3 Digital SimulationMethod 87
4.4.3.1 Maximum Allowable Photovoltaic Capacity in Static Simulation 87
4.4.3.2 Maximum Allowable Photovoltaic Capacity in Dynamic Simulations 87
4.5 Maximum Allowable Capacity of Distributed Photovoltaics Based on Random Scenario Method 88
4.5.1 Algorithm Introduction 88
4.5.2 Case Study 89
4.6 Photovoltaic Penetration Improvement 93
4.6.1 Full Utilization of the Reactive Power Regulation Capability of a Distributed Photovoltaic System 93
4.6.2 Distribution Network Upgrade 93
4.6.3 Demand–Side Response 93
4.6.4 Energy Storage Technologies 94
4.7 Summary 94
References 94
5 Power Flow Analysis for Distribution Networks with High Penetration of Photovoltaics 97
5.1 Introduction 97
5.2 Power Flow Calculation for Distribution Networks with Distributed Photovoltaics 97
5.2.1 Comparison between Power Flow Calculation Methods for Distribution Networks 97
5.2.2 Power Flow CalculationModel for a Distributed Photovoltaics 99
5.2.3 Power Flow CalculationMethod for Distribution Network with Distributed Photovoltaics 100
5.3 Voltage Impact Analysis of Distributed Photovoltaics on Distribution Networks 101
5.3.1 MathematicalModel 101
5.3.2 Simulation Studies 103
5.4 Loss Analysis in Distribution Network with Distributed Photovoltaics 108
5.4.1 MathematicalModel 108
5.4.2 Simulation Results 110
5.5 Real Case Studies 112
5.5.1 Patterns for Distributed Photovoltaics Interconnection 112
5.5.2 Analysis on a Feeder 114
5.5.3 Analysis on SA Substation 118
5.6 Summary 123
References 123
6 Voltage Control for Distribution Network with High Penetration of Photovoltaics 125
6.1 Introduction 125
6.2 Voltage Impact Analysis in the Distribution Network with Distributed Photovoltaics 126
6.3 Voltage Control Measures 130
6.3.1 Automatic Voltage Control System 130
6.3.2 Feeder–Level Voltage Regulation 130
6.3.3 Photovoltaic Inverter 131
6.4 Photovoltaic Inverter Control Strategies 132
6.4.1 General Control Principle 132
6.4.2 Constant Power Factor Control Strategy 132
6.4.3 Variable Power Factor Control Strategy 133
6.4.4 Voltage Adaptive Control Strategy 134
6.4.4.1 Q/V Droop Control 134
6.4.4.2 P/V Droop control 136
6.4.4.3 Inverter Parameter Optimization 136
6.5 Modeling and Simulation 137
6.5.1 Approaches 137
6.5.2 Introduction to OpenDSS 138
6.5.3 SimulationModels 138
6.5.3.1 Automatic Voltage Control System 139
6.5.3.2 Photovoltaic SystemModel 142
6.6 Simulation Analysis 144
6.6.1 Basic Data Preparation for Simulation 144
6.6.2 Analysis of Power Flow and Voltage in Extreme Scenarios with Automatic Voltage Control 147
6.6.2.1 Working Day (July 16, 2014) Scenario 147
6.6.2.2 Holiday (May 1, 2014) Scenario 149
6.6.3 Participation of Photovoltaic Inverter in Voltage Regulation 151
6.6.3.1 Working Day (July 16, 2014) Scenario 151
6.6.3.2 Holiday (May 1, 2014) Scenario 156
6.7 Summary 163
References 163
7 Short–Circuit Current Analysis of Grid–Connected Distributed Photovoltaic Generation 165
7.1 Introduction 165
7.2 Short–Circuit Characteristic Analysis of Distributed Photovoltaic Generation 165
7.2.1 Short–Circuit Characteristic Analysis of Symmetric Voltage Sag of Power Grid 166
7.2.2 Short–Circuit Characteristic Analysis of Asymmetrical Voltage Sag of Power Grid 167
7.3 Low–Voltage Ride–Through Techniques of Photovoltaic Generation 169
7.3.1 Review of Low–Voltage Ride–Through Standards 170
7.3.2 Low–Voltage Ride–Through Control Strategy for Photovoltaic Generation 171
7.4 Simulation Studies 174
7.4.1 Fault Simulations of Photovoltaic Generation without the Low–Voltage Ride–Through Function 174
7.4.2 Fault Simulation of Photovoltaic Generation with the Low–Voltage Ride–Through Function 176
7.4.2.1 Case 1: 80% Voltage Drop ofThree Phases 176
7.4.2.2 Case 2: 80% Voltage Drop of Two Phases 176
7.4.2.3 Case 3: 80% Voltage Drop of a Single Phase 177
7.5 Calculation Method for Short–Circuit Currents in Distribution Network with Distributed Photovoltaic Generation 179
7.5.1 Distribution NetworkModel 180
7.5.2 Calculation Method for Short–Circuit Currents in a Traditional Distribution Network 180
7.5.2.1 Operational Curve Law 181
7.5.2.2 IEC Standard 181
7.5.2.3 ANSI Standard 181
7.5.3 Calculation Method for Short–Circuit Currents in a Distribution Network with Distributed Photovoltaic Generation 182
7.5.3.1 Calculation Method for Symmetric Fault Short–Circuit Currents 183
7.5.3.2 Calculation Method for Asymmetric Fault Short–Circuit Currents 184
7.5.4 Fault Simulation Studies of Distribution Network with Distributed Photovoltaic Generation 186
7.6 Summary 191
References 192
8 Power Quality in Distribution Networks with Distributed Photovoltaic Generation 195
8.1 Introduction 195
8.2 Power Quality Standards and Applications 195
8.2.1 Power Quality Standards for Grid–Connected Photovoltaic Generation 196
8.2.2 Power Quality Requirements Stipulated in Standards for Grid–Connected Photovoltaic Generation 196
8.2.2.1 Voltage Deviation 197
8.2.2.2 Voltage Fluctuation and Flicker 198
8.2.2.3 Voltage Unbalance Factor 199
8.2.2.4 DC Injection 199
8.2.2.5 Current Harmonics 199
8.2.2.6 Voltage Harmonics 204
8.3 Evaluation and Analysis of Voltage Fluctuation and Flicker for Grid–Connected Photovoltaic Generation 206
8.3.1 Evaluation Process 207
8.3.1.1 First–Level Provisions 207
8.3.1.2 Second–Level Provisions 207
8.3.1.3 Third–Level Provisions 208
8.3.2 Calculation 208
8.3.2.1 The First–Level Evaluation for Photovoltaic Integration 208
8.3.2.2 The Second–Level Evaluation 208
8.4 Harmonic Analysis for Grid–Connected Photovoltaic Generation 211
8.4.1 Fundamentals of Harmonic Analysis 211
8.4.1.1 Harmonic Simulation Platform 211
8.4.1.2 Photovoltaic Harmonic Model 213
8.4.2 Harmonic Analysis of Photovoltaic Generation Connected to a Typical Feeder 218
8.4.2.1 Harmonics Analysis of Centralized Photovoltaic Connection 219
8.4.2.2 Harmonics Analysis of Photovoltaic Connection in a DistributedWay 223
8.4.3 Analysis of Practical Cases 224
8.5 Summary 225
References 225
9 Techniques for Mitigating Impacts of High–Penetration Photovoltaics 227
9.1 Introduction 227
9.2 Energy Storage Technology 227
9.2.1 Classification of Energy Storage Technologies 228
9.2.1.1 Mechanical Energy Storage 228
9.2.1.2 Electromagnetic Energy Storage 229
9.2.1.3 Phase–Change Energy Storage 229
9.2.1.4 Chemical Energy Storage 229
9.2.2 Electrochemical Energy Storage 229
9.2.2.1 Lead Acid Battery 230
9.2.2.2 Lithium–Ion Battery 231
9.2.2.3 Flow Cell 232
9.2.3 Electrochemical Energy Storage Model 233
9.2.3.1 MathematicalModel 233
9.2.3.2 Life Model 235
9.3 Application of Energy Storage Technology in High–Penetration Distributed Photovoltaics 236
9.3.1 Siting and Sizing Methods for Energy Storage System 236
9.3.1.1 Siting of Energy Storage System 236
9.3.1.2 Sizing of the Energy Storage System 237
9.3.2 Case Simulation 238
9.4 Demand Response 242
9.4.1 Introduction 242
9.4.1.1 Price–Based Demand Response 242
9.4.1.2 Incentive–Based Demand Response 243
9.4.2 Load Characteristics of Demand Response 245
9.5 Application of Demand Response in Distribution Networks with High Penetration of Distributed Photovoltaics 247
9.5.1 Incentive–Based Demand Response OptimizationModel 247
9.5.1.1 Incentive–Based Demand Response Model 247
9.5.1.2 Constraints 249
9.5.2 Incentive–Based Demand Response Algorithm 249
9.5.3 Case Simulation 251
9.6 Cluster Partition Control 252
9.7 Application of Cluster Partition Control in Distributed Grid with High–Penetration Distributed Photovoltaics 256
9.7.1 Community–Detection–Based Optimal Network Partition 256
9.7.2 Sub–community Reactive/Active Power–Voltage Control Scheme 259
9.7.3 Case Study 261
9.8 Summary 270
References 271
10 Design and Implementation of Stand–aloneMultisource Microgrids with High–Penetration Photovoltaic Generation 273
10.1 Introduction 273
10.2 System Configurations of Microgrids with Multiple Renewable Sources 274
10.2.1 Integration Schemes 274
10.2.2 Unit Sizing and Technology Selection 277
10.3 Controls and Energy Management 278
10.3.1 Centralized Control Paradigm 278
10.3.2 Distributed Control Paradigm 279
10.3.3 Hybrid Hierarchical Control Paradigm 280
10.4 Implementation of Stand–alone Microgrids 281
10.4.1 Dongfushan Microgrid: Joint Optimization of Operation and Component Sizing 282
10.4.1.1 System Configuration 282
10.4.1.2 Operating Strategy 283
10.4.1.3 OptimizationModel 287
10.4.1.4 System Sizing Optimization 291
10.4.1.5 Optimal Configuration and Operation Practice 297
10.4.2 Plateau Microgrid: A Multiagent–System–Based Energy Management System 299
10.4.2.1 System Configuration 299
10.4.2.2 Multiagent–System–Based Energy ManagementMethod 301
10.4.2.3 Validation of the Microgrid Energy Management System 307
10.5 Summary 309
References 310
Index 315
