High Voltage Direct Current Transmission

This comprehensive reference guides the reader through all HVDC technologies, including LCC (Line Commutated Converter), 2-level VSC and VSC HVDC based on modular multilevel converters (MMC) for an in-depth understanding of converters, system level design, operating principles and modeling. Written in a tutorial style, the book also describes the key principles of design, control, protection and operation of DC transmission grids, which will be substantially different from the practice with AC transmission grids.

The first dedicated reference to the latest HVDC technologies and DC grid developments; this is an essential resource for graduate students and researchers as well as engineers and professionals working on the design, modeling and operation of DC grids and HVDC.

Key features:

• Provides comprehensive coverage of LCC, VSC and (half and full bridge) MMC-based VSC technologies and DC transmission grids.
• Presents phasor and dynamic analytical models for each HVDC technology and DC grids.
• Includes HVDC protection, studies of DC and AC faults, as well as system-level studies of AC-DC interactions and impact on AC grids for each HVDC technology.
• Companion website hosts SIMULINK SimPowerSystems models with examples for all HVDC topologies.

Auteur

**Professor Dragan Jovcic, University of Aberdeen, Scotland, UK
**Professor Jovcic has been with the University of Aberdeen since 2004. Between 2000 and 2004 he worked as a Lecturer with the University of Ulster. He was a Design Engineer in the New Zealand power industry between 1999 and 2000, and a visiting professor on a 6-months appointment at McGill University, Canada in 2008. His research career has focused on HVDC, FACTS and DC grids. Professor Jovcic has published around 80 articles related to HVDC and power electronics applications, to transmission systems. He has supervised numerous externally funded research projects with the total budget of over £2.5million. He has thirteen years of university teaching experience in the subjects of electrical engineering and control in UK. Professor Jovcic is Senior member of IEEE and a CIGRE member; he is also a member of three CIGRE working groups.

Dr Khaled Ahmed, University of Aberdeen, Scotland, UK
Dr Ahmed has been working in the renewable energy field for more than eight years. He has been a researcher on two main projects sponsored by the EPSRC research council. He is a senior member of the IEEE industrial electronics society and has published over 53 technical papers in refereed journals and conferences related to renewable energy applications, modular multilevel converter based applications, and HVDC systems. Dr Ahmed has eleven years of university teaching experience in the subjects of electrical engineering, power electronics and control in Egypt and the UK. Recently, he was part of a 2-lecturer team who designed and delivered a continuing professional development (CPD) course on HVDC for the SSE HVDC technology engineering team (SSE is a leading electricity and gas company, operating mainly in the UK and Ireland).

Contenu

Contents Preface xi Part I HVDC with Current Source Converters 1 1 Introduction to Line-Commutated HVDC 3 1.1 HVDC Applications 3 1.2 Line-Commutated HVDC Components 5 1.3 DC Cables and Overhead Lines 6 1.4 LCC HVDC Topologies 7 1.5 Losses in LCC HVDC Systems 9 1.6 Conversion of AC Lines to DC 10 1.7 Ultra-High Voltage HVDC 10 2 Thyristors 12 2.1 Operating Characteristics 12 2.2 Switching Characteristic 13 2.3 Losses in HVDC Thyristors 17 2.4 Valve Structure and Thyristor Snubbers 20 2.5 Thyristor Rating Selection and Overload Capability 22 3 Six-Pulse Diode and Thyristor Converter 23 3.1 Three-Phase Uncontrolled Bridge 23 3.2 Three-Phase Thyristor Rectifier 25 3.3 Analysis of Commutation Overlap in a Thyristor Converter 26 3.4 Active and Reactive Power in a Three-Phase Thyristor Converter 30 3.5 Inverter Operation 31 4 HVDC Rectifier Station Modelling, Control and Synchronization with AC Systems 35 4.1 HVDC Rectifier Controller 35 4.2 Phase-Locked Loop (PLL) 36 5 HVDC Inverter Station Modelling and Control 40 5.1 Inverter Controller 40 5.2 Commutation Failure 42 6 HVDC System V-I Diagrams and Operating Modes 45 6.1 HVDC-Equivalent Circuit 45 6.2 HVDC V-I Operating Diagram 45 6.3 HVDC Power Reversal 48 7 HVDC Analytical Modelling and Stability 53 7.1 Introduction to Converters and HVDC Modelling 53 7.2 HVDC Analytical Model 54 7.3 CIGRE HVDC Benchmark Model 56 7.4 Converter Modelling, Linearization and Gain Scheduling 56 7.5 AC System Modelling for HVDC Stability Studies 58 7.6 LCC Converter Transformer Model 62 7.7 DC System Model 63 7.8 HVDC-HVAC System Model 65 7.9 Analytical Dynamic Model Verification 65 7.10 Basic HVDC Dynamic Analysis 66 7.11 HVDC Second Harmonic Instability 70 7.12 Oscillations of 100 Hz on the DC Side 71 8 HVDC Phasor Modelling and Interactions with AC System 72 8.1 Converter and DC System Phasor Model 72 8.2 Phasor AC System Model and Interaction with the DC System 73 8.3 Inverter AC Voltage and Power Profile as DC Current is Increasing 75 8.4 Influence of Converter Extinction Angle 76 8.5 Influence of Shunt Reactive Power Compensation 78 8.6 Influence of Load at the Converter Terminals 78 8.7 Influence of Operating Mode (DC Voltage Control Mode) 78 8.8 Rectifier Operating Mode 80 9 HVDC Operation with Weak AC Systems 82 9.1 Introduction 82 9.2 Short-Circuit Ratio and Equivalent Short-Circuit Ratio 82 9.3 Power Transfer between Two AC Systems 85 9.4 Phasor Study of Converter Interactions with Weak AC Systems 89 9.5 System Dynamics (Small Signal Stability) with Low SCR 90 9.6 Control and Main Circuit Solutions for Weak AC Grids 90 9.7 LCC HVDC with SVC (Static VAR Compensator) 91 9.8 Capacitor-Commutated Converters for HVDC 93 9.9 AC System with Low Inertia 93 10 Fault Management and HVDC System Protection 98 10.1 Introduction 98 10.2 DC Line Faults 98 10.3 AC System Faults 101 10.4 System Reconfiguration for Permanent DC Faults 103 10.5 Overvoltage Protection 106 11 LCC HVDC System Harmonics 107 11.1 Harmonic Performance Criteria 107 11.2 Harmonic Limits 108 11.3 Thyristor Converter Harmonics 109 11.4 Harmonic Filters 110 11.5 Noncharacteristic Harmonic Reduction Using HVDC Controls 118 Bibliography Part I Line Commutated Converter HVDC 119 Part II HVDC with Voltage Source Converters 121 12 VSC HVDC Applications and Topologies, Performance and Cost Comparison with LCC HVDC 123 12.1 Voltage Source Converters (VSC) 123 12.2 Comparison with Line-Commutated Converter (LCC) HVDC 125 12.3 Overhead and Subsea/Underground VSC HVDC Transmission 126 12.4 DC Cable Types with VSC HVDC 129 12.5 Monopolar and Bipolar VSC HVDC Systems 129 12.6 VSC HVDC Converter Topologies 130 12.7 VSC HVDC Station Components 135 12.8 AC Reactors 139 12.9 DC Reactors 139 13 IGBT Switches and VSC Converter Losses 141 13.1 Introduction to IGBT and IGCT 141 13.2 General VSC Converter Switch Requirements 142 13.3 IGBT Technology 142 13.4 Development of High Power IGBT Devices 147 13.5 IEGT Technology 148 13.6 Losses Calculation 148 13.7 Balancing Challenges in Series IGBT Chains 154 13.8 Snubbers Circuits 155 14 Single-Phase and Three-Phase Two-Level VSC Converters 156 14.1 Introduction 156 14.2 Single-Phase Voltage Source Converter 156 14.3 Three-Phase Voltage Source Converter 159 14.4 Square-Wave, Six-Pulse Operation 159 15 Two-Level PWM VSC Converters 167 15.1 Introduction 167 15.2 PWM Modulation 167 15.3 Sinusoidal Pulse-Width Modulation (SPWM) 168 15.4 Third Harmonic Injection (THI) 171 15.5 Selective Harmonic Elimination Modulation (SHE) 172 15.6 Converter Losses for Two-Level SPWM VSC 173 15.7 Harmonics with Pulse-Width Modulation (PWM) 175 15.8 Comparison of PWM Modulation Techniques 178 16 Multilevel VSC Converters 180 16.1 Introduction 180 16.2 Modulation Techniques for Multilevel Converters 182 16.3 Neutral Point Clamped Multilevel Converter 183 16.4 Flying …