Smart Grid
Technology and Applications

Electric power systems worldwide face radical transformation with the need to decarbonise electricity supply, replace ageing assets and harness new information and communication technologies (ICT). The Smart Grid uses advanced ICT to control next generation power systems reliably and efficiently. This authoritative guide demonstrates the importance of the Smart Grid and shows how ICT will extend beyond transmission voltages to distribution networks and customer-level operation through Smart Meters and Smart Homes.

Smart Grid Technology and Applications:

• Clearly unravels the evolving Smart Grid concept with extensive illustrations and practical examples.
• Describes the spectrum of key enabling technologies required for the realisation of the Smart Grid with worked examples to illustrate the applications.
• Enables readers to engage with the immediate development of the power system and take part in the debate over the future Smart Grid.
• Introduces the constituent topics from first principles, assuming only a basic knowledge of mathematics, circuits and power systems.
• Brings together the expertise of a highly experienced and international author team from the UK, Sri Lanka, China and Japan.

Electrical, electronics and computer engineering researchers, practitioners and consultants working in inter-disciplinary Smart Grid RD&D will significantly enhance their knowledge through this reference. The tutorial style will greatly benefit final year undergraduate and master?s students as the curriculum increasing focuses on the breadth of technologies that contribute to Smart Grid realisation.

About the authors xi

Preface xiii

Acknowledgements xv

List of abbreviations xvii

1 The Smart Grid 1

1.1 Introduction 1

1.2 Why implement the Smart Grid now? 2

1.2.1 Ageing assets and lack of circuit capacity 2

1.2.2 Thermal constraints 2

1.2.3 Operational constraints 3

1.2.4 Security of supply 3

1.2.5 National initiatives 4

1.3 What is the Smart Grid? 6

1.4 Early Smart Grid initiatives 7

1.4.1 Active distribution networks 7

1.4.2 Virtual power plant 9

1.4.3 Other initiatives and demonstrations 9

1.5 Overview of the technologies required for the Smart Grid 12

References 14

Part I Information and Communication Technologies

2 Data communication 19

2.1 Introduction 19

2.2 Dedicated and shared communication channels 19

2.3 Switching techniques 23

2.3.1 Circuit switching 24

2.3.2 Message switching 24

2.3.3 Packet switching 24

2.4 Communication channels 25

2.4.1 Wired communication 27

2.4.2 Optical fibre 29

2.4.3 Radio communication 33

2.4.4 Cellular mobile communication 34

2.4.5 Satellite communication 34

2.5 Layered architecture and protocols 35

2.5.1 The ISO/OSI model 36

2.5.2 TCP/IP 40

References 43

3 Communication technologies for the Smart Grid 45

3.1 Introduction 45

3.2 Communication technologies 46

3.2.1 IEEE 802 series 46

3.2.2 Mobile communications 59

3.2.3 Multi protocol label switching 60

3.2.4 Power line communication 62

3.3 Standards for information exchange 62

3.3.1 Standards for smart metering 62

3.3.2 Modbus 63

3.3.3 DNP 3 64

3.3.4 IEC 61850 65

References 66

4 Information security for the Smart Grid 69

4.1 Introduction 69

4.2 Encryption and decryption 70

4.2.1 Symmetric key encryption 71

4.2.2 Public key encryption 75

4.3 Authentication 76

4.3.1 Authentication based on shared secret key 76

4.3.2 Authentication based on key distribution centre 77

4.4 Digital signatures 77

4.4.1 Secret key signature 77

4.4.2 Public key signature 77

4.4.3 Message digest 78

4.5 Cyber security standards 79

4.5.1 IEEE 1686: IEEE standard for substation intelligent electronic devices (IEDs) cyber security capabilities 79

4.5.2 IEC 62351: Power systems management and associated information exchange – data and communications security 80

References 80

Part II Sensing, Measurement, Control and Automation Technologies

5 Smart metering and demand-side integration 83

5.1 Introduction 83

5.2 Smart metering 84

5.2.1 Evolution of electricity metering 84

5.2.2 Key components of smart metering 86

5.3 Smart meters: An overview of the hardware used 86

5.3.1 Signal acquisition 87

5.3.2 Signal conditioning 89

5.3.3 Analogue to digital conversion 90

5.3.4 Computation 94

5.3.5 Input/output 95

5.3.6 Communication 96

5.4 Communications infrastructure and protocols for smart metering 96

5.4.1 Home-area network 96

5.4.2 Neighbourhood area network 97

5.4.3 Data concentrator 98

5.4.4 Meter data management system 98

5.4.5 Protocols for communications 98

5.5 Demand-side integration 99

5.5.1 Services provided by DSI 100

5.5.2 Implementations of DSI 104

5.5.3 Hardware support to DSI implementations 107

5.5.4 Flexibility delivered by prosumers from the demand side 109

5.5.5 System support from DSI 110

References 111

6 Distribution automation equipment 113

6.1 Introduction 113

6.2 Substation automation equipment 114

6.2.1 Current transformers 116

6.2.2 Voltage transformers 121

6.2.3 Intelligent electronic devices 121

6.2.4 Bay controller 124

6.2.5 Remote terminal units 124

6.3 Faults in the distribution system 125

6.3.1 Components for fault isolation and restoration 127

6.3.2 Fault location, isolation and restoration 132

6.4 Voltage regulation 135

References 139

7 Distribution management systems 141

7.1 Introduction 141

7.2 Data sources and associated external systems 142

7.2.1 SCADA 143

7.2.2 Customer information system 144

7.3 Modelling and analysis tools 144

7.3.1 Distribution system modelling 144

7.3.2 Topology analysis 149

7.3.3 Load forecasting 151

7.3.4 Power flow analysis 152

7.3.5 Fault calculations 156

7.3.6 State estimation 160

7.3.7 Other analysis tools 165

7.4 Applications 165

7.4.1 System monitoring 165

7.4.2 System operation 166

7.4.3 System management 168

7.4.4 Outage management system (OMS) 168

References 171

8 Transmission system operation 173

8.1 Introduction 173

8.2 Data sources 173

8.2.1 IEDs and SCADA 173

8.2.2 Phasor measurement units 174

8.3 Energy management systems 177

8.4 Wide area applications 179

8.4.1 On-line transient stability controller 181

8.4.2 Pole-slipping preventive controller 181

8.5 Visualisation techniques 183

8.5.1 Visual 2-D presentation 184

8.5.2 Visual 3-D presentation 185

References 186

Part III Power Electronics and Energy Storage

9 Power electronic converters 189

9.1 Introduction 189

9.2 Current source converters 191

9.3 Voltage source converters 195

9.3.1 VSCs for low and medium power applications 196

9.3.2 VSC for medium and high power applications 199

References 203

10 Power electronics in the Smart Grid 205

10.1 Introduction 205

10.2 Renewable energy generation 206

10.2.1 Photovoltaic systems 206

10.2.2 Wind, hydro and tidal energy systems 209

10.3 Fault current limiting 213

10.4 Shunt compensation 217

10.4.1 D-STATCOM 218

10.4.2 Active filtering 224

10.4.3 Shunt compensator with energy storage 224

10.5 Series compensation 228

References 231

11 Power electronics for bulk power flows 233

11.1 Introduction 233

11.2 FACTS 234

11.2.1 Reactive power compensation 235

11.2.2 Series compensation 241

11.2.3 Thyristor-controlled phase shifting transformer 243

11.2.4 Unified power flow controller 245

11.2.5 Interline power flow controller 246

11.3 HVDC 248

11.3.1 Current source converters 249

11.3.2 Voltage source converters 253

11.3.3 Multi-terminal HVDC 256

References 257

12 Energy storage 259

12.1 Introduction 259

12.2 Energy storage technologies 263

12.2.1 Batteries 263

12.2.2 Flow battery 264

12.2.3 Fuel cell and hydrogen electrolyser 266

12.2.4 Flywheels 267

12.2.5 Superconducting magnetic energy storage systems 270

12.2.6 Supercapacitors 270

12.3 Case study 1: Energy storage for wind power 271

12.4 Case study 2: Agent-based control of electrical vehicle battery charging 273

References 277

Index 279

Dr Kithsiri Liyanage, University of Peradeniya, Sri Lanka
Dr Liyanage is Senior Lecturer in the Department of Electrical and Electronic Engineering, University of Peradeniya. Prior to this he served as Dean of the Faculty of Engineering, University of Ruhuna and as Director of the Information Technology Centre, University of Peradenyia. He has been with the University of Tokyo as a Visiting Research Fellow since 2008.  He has served as coordinator of and consultant to several ICT and power generation projects.

Dr Jianzhong Wu, Cardiff University, UK
Dr Wu is a lecturer at the Institute of Energy, School of Engineering, Cardiff University. Privious to this he was a research fellow at the University of Manchester and Associate Professor at Tianjin University, China. He has been involved in several Chinese national research programmes, developing advanced software tools for distribution network operation, planning, for on-line security monitoring, assessment and optimisation for transmission networks.

Professor Akihiko Yokoyama, University of Tokyo, Japan
Professor Yokoyama is based at the Department of Engineering at the University of Tokyo. He is alsoProfessor in the Department of Advanced Energy at the Graduate School of Fro