Ultra high voltage AC DC power transmission ( TQL )

Subject to the energy transmission capacity andenvironmental protection requirements, China will inevitably develop thelong-distance and large-capacity power transmission technology to i

Ultra-high

Voltage AC/DC

Power Transmission

123

Hao Zhou et al Editors

Advanced Topics in Science and Technology in China

in China

in Science and Technology in China, Zhejiang University Press and Springer jointlypublish monographs by Chinese scholars and professors, as well as invited authorsand editors from abroad who are outstanding experts and scholars in theirfields.This series will be of interest to researchers, lecturers, and graduate students alike.Advanced Topics in Science and Technology in China aims to present the latest andmost cutting-edge theories, techniques, and methodologies in various research areas

in China It covers all disciplines in the fields of natural science and technology,including but not limited to, computer science, materials science, life sciences,engineering, environmental sciences, mathematics, and physics

More information about this series at http://www.springer.com/series/7887

Hao Zhou Wenqian Qiu

Editors

Ultra-high Voltage AC/DC Power Transmission

123

China Energy Engineering Group

Zhejiang Electric Power Design Institute Co., Ltd.

China Energy Engineering Group

Zhejiang Electric Power Design Institute Co., Ltd.

China Energy Engineering Group

Zhejiang Electric Power Design Institute Co., Ltd.

Hangzhou

China

Dongju Wang College of Electrical Engineering Zhejiang University

Hangzhou China Bincai Zhao State Grid Weifang Power Supply Company Weifang

China Jiyuan Li College of Electrical Engineering Zhejiang University

Hangzhou China Sha Li College of Electrical Engineering Zhejiang University

Hangzhou China Yuting Qiu College of Electrical Engineering Zhejiang University

Hangzhou China Jingzhe Yu College of Electrical Engineering Zhejiang University

Hangzhou China

Advanced Topics in Science and Technology in China

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Viewed from the distribution of the energy resources throughout China, though thetotal reserves are abundant, the resource distribution and productivity distributionare rather unbalanced The coal resource is mostly located in the North andNorthwest China, the hydropower resource is mainly located in the SouthwestChina, the onshore wind energy and solar energy resources are mainly located inthe Northwest China, while the energy demands are mainly concentrated in theCentral China and China’s east coastal areas The distance between the energy baseand the load center is up to 1000 km The energy resources used for power gen-eration are mainly coal and water, and the energy resources and productivitydevelopment are reversely distributed, which is the basic national condition ofChina Since the reform and opening-up, the electricity demand of China has beencontinuously and rapidly increased, and the scale and capacity of the newly builtpower sources have been increased Subject to the energy transmission capacity andenvironmental protection requirements, China will inevitably develop thelong-distance and large-capacity power transmission technology to improve thedevelopment and utilization rate of the resources, alleviate the pressure in theenergy transmission, and meet the requirements of the environmental protection.The UHV power transmission technology is the power transmission technologywith the highest voltage level in the world presently, and the most prominentcharacteristic thereof is the large-capacity, long-distance, and low-loss powertransmission The transmission capacity of the 1000 kV UHVAC system is about

4–5 times that of the 500 kV extra-high voltage (EHV) AC system The opment of the UHVAC and UHVDC power transmission can effectively solve theissue of large-scale power transmission In addition, compared with the EHV powertransmission line, the UHV line occupies less land resource and achieves quiteprominent economic and social benefits under the same power transmissioncapacity The building of the national-level power grid in which the UHV grid acts

devel-as the backbone and the grids of all levels develop in a coordinated manner,meeting the basic national condition of China that the energy resources and eco-nomic development are reversely distributed and according with the China’s overallarrangement for energy-saving and emission reduction, is the effective way to

v

realize the coordinated development of grids and power sources and the urgentdemand for the construction of the resource-saving and environment-friendlysociety.

In the world, a few countries such as the former Soviet Union, Japan, America,Italy, and Canada have ever conducted tests and researches on the UHVAC powertransmission technology During 1981–1994, the former Soviet Union successfullybuilt a total of 2364 km 1150 kV power transmission lines, among which, theEkibastuz–Kokshetau line (495 km in length) put into operation at 1150 kV in 1985was thefirst UHV power transmission line put into actual operation in the world.Japan built the 1000 kV UHVAC double-circuit power transmission line in the1990s , which, however, was under the 500 kV reduced voltage operation all thetime The overseas DC power transmission project with the highest voltage levelthat has been built and put into operation is the Itapúa Power Transmission Project

in Brazil, which includes double-circuit DC line with voltage level of±600 kV andrated transmission power of 3600 MW The Soviet Union ever planned to build a

±750 kV UHVDC power transmission line project from Ekibastuz toTambovskaya Oblast, the first engineering practice of the UHVDC power trans-mission technology in the world, and commenced the construction in 1980, butfinally ceased the construction due to the political and economic reasons, after thecompletion of the construction of 1090 km-long line

The research on the UHV power transmission was started relatively late inChina Since 1986, the research on the UHV power transmission has been suc-cessively included in the key science and technology research programs duringChina’s “Seventh Five-Year Plan,” “Eighth Five-Year Plan,” and “Tenth Five-YearPlan” During 1990–1995, the Significant Project Office of the State Councilorganized the“Demonstration of Long-distance Transmission Modes and VoltageLevels”; and during 1990–1999, the State Scientific and TechnologicalCommission organized the monographic researches such as the “PreliminaryDemonstration of UHV Power Transmission” and “Feasibility of Application of

AC Megavolt Ultra-high Voltage for Power Transmission” State Grid Corporation

of China put forward for the strategic concept of“establishment of the UHV-basedrobust state grid” in 2004 the first time to focus on the construction of a networksystem in which the UHV grid acts as the backbone and the grids of all levelsdevelop in a coordinated manner China Southern Power Grid Co., Ltd also began

to study the feasibility in the construction of ±800 kV DC power transmissionproject in 2003 In 2006, the National Development and Reform Commissionformally approved the 1000 kV UHVAC Demonstration Project from SoutheastShanxi through Nanyang to Jingmen connecting the North China grid and CentralChina grid In 2007 and 2010, China respectively completed and put into operationthe 1000 kV Southeast Shanxi–Nanyang–Jingmen UHVAC Power TransmissionDemonstration Project and ±800 kV Yunnan–Guangdong and Xiangjiaba–Shanghai UHVDC Power Transmission Projects Since then, the UHV powertransmission has accomplished a rapid development in China Up to August 2017,six 1000 kV UHVAC power transmission lines and nine±800 kV UHVDC powertransmission lines have been built and put into operation There is still another 1000

kV UHVAC power transmission line and the other four±800 kV UHVDC powertransmission lines will be put into operation at the end of 2017 Moreover, one

±1100 kV UHVDC power transmission line is being built and will be put intooperation in 2018

The UHV power transmission is the engineering technology leading the world’spower transmission technology Its rapid and successful development in China hasfully proven the tremendous achievement accomplished by China in the techno-logical aspect of the electric power system Meanwhile, the complexity of the UHVpower transmission technology and the urgency of its development in China requirethat the professional personnel engaging in the work related to the electric powersystem have a deeper understanding and mastery of it Based on the significantresearch results obtained by Zhejiang University High Voltage Laboratory in thefield of UHVAC and UHVDC power transmission in the last decade and theabundant practical experience accumulated by Zhejiang Electric Power DesignInstitute in thefield of UHV power transmission engineering over the years, and incombination with the relevant research results in the aspect of UHVAC andUHVDC power transmission technology and the actual operation experience inChina and abroad, this book systematically introduces the key technical issuesexisting in the UHVAC and UHVDC power transmission

This book consists of four sections containing a total of 28 chapters, and focuses

on the study of the overvoltage, insulation coordination and design of the UHVpower grid Section I, consisting of three chapters provides an overview of thedevelopment of the UHV power transmission and the system characteristics andeconomy thereof Section II, consisting of ten chapters discusses the UHVACsystem Section III, consisting of ten chapters discusses the UHVDC system.Section IV, consisting of four chapters discusses the design of the UHVAC sub-station and UHVDC converter station as well as UHVAC and DC power trans-mission lines Hao Zhou is responsible for thefinal compilation and editing of thewhole book, and Wenqian Qiu, Xu Deng, Jiyuan Li and Jingzhe Yu act as the chiefreviewers

We sincerely hope that this book can better help the readers understand theUHVAC and UHVDC power transmission technology and can provide referencefor the research work carried out by the technicians engaging in the work related tothe electric power system This book is jointly edited by the relevant researchersfrom Zhejiang University, Zhejiang Electric Power Design Institute, State GridZhejiang Electric Power Company, China Electric Power Research Institute, ChinaSouthern Power Grid Corporation, East China Grid Company Limited, SouthwestElectric Power Design Institute, and North China Electric Power University Theediting of this book has received the guidance and help from numerous experts.Gratitude is hereby expressed to Academician Han Zhenxiang, Academician ChenWeijiang, Professor Zhao Zhida, Professorate Senior Engineer Zhou Peihong,Professorate Senior Engineer Zhang Cuixia, Professorate Senior Engineer LiYongwei, Professorate Senior Engineer Gu Dingxie, Professorate Senior EngineerNie Dingzhen, Professorate Senior Engineer Tian Jie, Professor Kang Chongqing,Professor Cui Xiang, Professor Li Chengrong, Professor Wen Fushuan, Professor

Xu Zheng, Professorate Senior Engineer Su Zhiyi, Professorate Senior Engineer

Wu Xiong, Professorate Senior Engineer Wan Baoquan, Professorate SeniorEngineer Sun Zhaoying, Professorate Senior Engineer Chen Jiahong, ProfessorateSenior Engineer Dai Min, Professorate Senior Engineer Li Zhibing, ProfessorateSenior Engineer Wang Xinbao, Senior Engineer Huang Ying, Senior EngineerShen Haibin, etc., for their support and help

The editing of this book had been in progress for nearly 8 years and erates the research results of the authors Nevertheless, due to the authors’ limitedtheoretical level and practical experience, inappropriateness and errors areunavoidable Any comment will be highly appreciated

August 2017

Part I Overview

1 Development of UHV Power Transmission 3

Ke Sun, Dongju Wang, Sha Li and Haifeng Qiu 1.1 UHV Power Transmission 4

1.1.1 Development of Power Transmission Voltage Level 4

1.1.2 Voltage Level Sequence in Power Grid 6

1.1.3 Selection of UHV Transmission Voltage Levels 11

1.2 Development of UHV Power Transmission Technology 16

1.2.1 The Former Soviet Union (Russia) 16

1.2.2 Japan 17

1.2.3 United States 19

1.2.4 Canada 20

1.2.5 Italy 20

References 21

2 Development of UHV Power Transmission in China 23

Ke Sun, Shichao Yuan and Yuting Qiu 2.1 Necessity in the Development of UHV Power Transmission in China 24

2.1.1 Objectively Required by the Sustained and Rapid Growth in Electricity Demands 24

2.1.2 Objectively Required by the Long-Distance and Large-Capacity Power Transmission 24

2.1.3 Objectively Required by the Basic Law of Power Grid Development 26

2.1.4 Required to Ensure Safe and Reliable Energy Transmission 26

2.2 Development Process of UHV Power Transmission in China 27

ix

2.2.1 Preliminary Study of UHV 27

2.2.2 Construction of UHV Test Base 28

2.2.3 China’s UHV Transmission Projects 31

References 37

3 Analysis on System Characteristics and Economy of UHV Power Transmission 39

Guang Chen, Hao Zhou, Jiyuan Li and Jingzhe Yu 3.1 System Characteristics of UHVAC Power Transmission 40

3.1.1 Reliability and Stability 40

3.1.2 Transmission Characteristics and Transmission Capacity 41

3.2 System Characteristics of UHVDC Power Transmission 48

3.2.1 Reliability and Stability 48

3.2.2 Transmission Characteristics and Transmission Capacity 51

3.3 Analysis on Economy of UHV Power Transmission 52

3.3.1 Comparison of Economy for UHVAC/EHVAC Power Transmission 52

3.3.2 Comparison of Economy for UHVDC/EHVDC Power Transmission 55

3.4 Applicable Occasions of UHVAC/UHVDC Power Transmissions 57

3.4.1 Technical Characteristics of UHVAC/UHVDC Power Transmissions 57

3.4.2 Technical Advantages of UHV Power Transmission 57

3.4.3 Interconnection of UHV Power Grids 58

3.4.4 Applicable Occasions of UHVAC/UHVDC Power Transmissions 60

References 65

Part II Alternating Current 4 Power Frequency Overvoltage of UHV Power Transmission Lines 69

Hao Zhou, Qiang Yi, Sha Li and Jingzhe Yu 4.1 Mechanisms of Power Frequency Overvoltage 70

4.1.1 No-Load Long-Line Capacitance Effect 70

4.1.2 Asymmetrical Short-Circuit Fault of the Line 73

4.1.3 Power Frequency Overvoltage due to Three-Phase Load Shedding 74

4.2 Characteristics of UHV Power Frequency Overvoltage 77

4.3 Categories of UHV Power Frequency Overvoltage 78

4.3.1 Classification of UHV Power Frequency

Overvoltage 78

4.3.2 Systematic Comparison of Various Power Frequency Overvoltage 82

4.4 Requirements on Restriction of UHV Power Frequency Overvoltage 92

4.5 Influence Factors of UHV Power Frequency Overvoltage 93

4.5.1 Line Length 93

4.5.2 Equivalent Impedance of Power Supply 94

4.5.3 Location of the Ground Fault Point 97

4.5.4 Transmission Power 102

4.5.5 Tower Structures of the Line 103

4.6 Restrictive Measures for UHV Power Frequency Overvoltage 104

4.6.1 Fixed High-Voltage Shunt Reactor 104

4.6.2 Controllable High-Voltage Shunt Reactor 110

4.6.3 Relay Protection Restriction Scheme 118

4.6.4 Selection of Restrictive Measures 120

4.7 Determination of the Upper and Lower Limits of Compensation Degree of High-Voltage Shunt Reactor 121

4.7.1 Determination of the Upper Limit of Compensation Degree of High-Voltage Shunt Reactor 122

4.7.2 Determination of the Lower Limit of Compensation Degree of High-Voltage Shunt Reactor 149

References 162

5 Secondary Arc Current of UHVAC System 163

Qiang Yi, Hao Zhou and Sha Li 5.1 Generation Mechanism of Secondary Arc Current 164

5.2 Measures to Extinguish the Secondary Arc 165

5.2.1 Connection of Small Reactance at the Shunt Reactor’s Neutral Point for Compensation 165

5.2.2 Extinguish of the Secondary Arc by Adding HSGS 181

5.2.3 Comparison and Discussion on the Two Methods to Restrict the Secondary Arc Current 185

5.3 Simulation of the Secondary Arc Current and the Recovery Voltage 188

5.3.1 Modeling 188

5.3.2 Analysis of Effect on Inhibiting the Secondary Arc by Connecting Small Reactance at the Neutral Point of Shunt Reactors 188

5.3.3 Analysis of the Effect of HSGS on the Inhibition of Secondary Arc 192

References 196

6 Switching Overvoltage of UHVAC Systems 199

Rongrong Ji, Hao Zhou and Xiujuan Chen 6.1 Switching Overvoltage Classification and Limiting Methods of UHVAC Systems 200

6.1.1 Switching Overvoltage Classification of UHVAC Systems 200

6.1.2 Common Methods for Limiting Switching Overvoltage in the UHVAC System 203

6.1.3 New Methods for Limiting Switching Overvoltage in the UHVAC System 207

6.2 Single-Phase Ground Fault Overvoltage 209

6.2.1 Mechanism for Generation 209

6.2.2 Modeling and Simulation 211

6.2.3 Analysis of Influence Factors 213

6.2.4 Limitation Measures 224

6.3 Closing Overvoltage 239

6.3.1 Mechanism for Generation 239

6.3.2 Modeling and Simulation 244

6.3.3 Analysis of Influence Factors 248

6.3.4 Limitation Measures 262

6.3.5 Research on Applicability of Closing Resistors for EHV and UHVAC Transmission Line Circuit Breakers 262

6.4 Opening Overvoltage 277

6.4.1 Load Shedding Overvoltage 278

6.4.2 Fault Clearing Overvoltage 285

6.5 Influence on the Electromagnetic Transient Characteristics by Series Compensation Device 293

6.5.1 Composition of Series Compensation Device 293

6.5.2 Influence on the Closing Switching Overvoltage by Series Compensation Device 294

6.5.3 Influence on Power Frequency Overvoltage by Series Compensation Device 294

6.5.4 Influence on Secondary Arc Current by Series Compensation Device 295

6.5.5 Linkage Between Series Compensation Device and Circuit Breaker 296

References 296

7 Very Fast Transient Overvoltage of UHVAC System 299

Yang Li, Guoming Ma and Hao Zhou 7.1 Generation Mechanism and Characteristics of VFTO 300

7.2 Harm of VFTO 303

7.2.1 Harm of VFTO to GIS Main Insulation 304

7.2.2 Influence of VFTO on Power Transformer 3047.2.3 Influence of VFTO on the Secondary Equipment 3077.2.4 Cumulative Effect of VFTO 3077.3 VFTO in 1000 kV GIS Substation Under Different Operation

Conditions 3077.3.1 VFTO Generated Due to Operation with Main

Transformer 3097.3.2 VFTO Generated Due to Operation with Outgoing

Line 3097.3.3 VFTO Generated Due to Operation with Busbar 3107.4 Influence Factors of VFTO 3117.4.1 Influence of the Residual Voltage at Load Side

on the Amplitude of VFTO 3127.4.2 Influence of the Capacitance at Inlet of Transformer

on VFTO 3127.4.3 Influence of Arc Resistance on the Amplitude

of VFTO 3137.4.4 Influence of Zinc Oxide Arrester on VFTO 3147.5 Comparison of VFTO in 500 and 1000 kV GIS Substations 3147.5.1 Switch Operation Sequence in Substation

Under Typical Disconnector Operating Mode 3157.5.2 VFTO Restriction Level by Equipment in 500/

1000 kV GIS Substation 3187.5.3 Comparison of VFTO in Typical 500 and 1000 kV

GIS Substations 3197.5.4 Conclusions on Influences on the 500 and 1000 kV

GIS Substations by VFTO 3247.5.5 Discussion on Whether to Install Parallel

Resistance of Disconnector in the 500 and 1000 kVGIS Substations 3257.6 Comparison of Characteristics of VFTO in Substation and

Power Plant 3257.6.1 Comparison of Wiring Diagrams for Substation

and Power Plant 3257.6.2 Comparison of Characteristics of VFTO in the

UHV GIS Substation and the Power Plant 3277.6.3 Conclusions on Comparison of VFTO in UHV GIS

Substation and Power Plant 3327.7 Restriction and Protection Measures 3337.7.1 Rational Arrangement of Operation Sequence

of Circuit Breakers and Disconnectors 3337.7.2 Installation of Generator Outlet Circuit Breaker

in the Power Plant 334

7.7.3 Additional Installation of Parallel Resistance

on the Disconnector 336

7.7.4 Ferrite Toroid 337

7.7.5 Overhead Line 338

7.7.6 Other Measures 339

7.8 Quantitative Study on the Restriction of Wave Front Steepness of VFTO Invading the Main Transformer Port by the Overhead Line 339

7.8.1 Experimental Study of the Influence on the VFTO Wave Front Steepness by the Overhead Line Length 340

7.8.2 Simulation Analysis of the Influence on the VFTO Wave Front Steepness by Overhead Line Length 343

7.8.3 Further Discussion on Restriction of Wave Front Steepness of VFTO Invading the Main Transformer by Means of Overhead Line in the 1000 kV Power Plant 350

7.9 Study on Transient Enclosure Voltage (TEV) of GIS in Substation and Power Plant 354

7.9.1 Principle for Its Generation 355

7.9.2 TEV Calculation Method 355

7.9.3 Measures to Reduce the Transient Enclosure Voltage 357

7.10 Experimental Investigation on VFTO Characteristics in the UHV GIS System in China 358

7.10.1 VFTO Characteristic Test Circuit 358

7.10.2 VFTO Generation Mechanism and Waveform Characteristics 360

7.10.3 Tests on the Effect of Operating Speed of Disconnectors on VFTO 362

7.10.4 Tests and Studies on the Effect of Branch Busbar Length on VFTO 368

7.10.5 Effect of Connection Direction of Disconnector Contacts on VFTO 371

7.11 Conclusions on VFTO Characteristics in the 500/1000 kV GIS Substation and Power Plant 377

References 380

8 Lightning Protection of UHVAC System 383

Bincai Zhao, Hao Zhou, Yuchuan Han and Jingzhe Yu 8.1 Lightning Protection of the UHVAC Lines 384

8.1.1 Overview 384

8.1.2 Calculation Methods for Assessment of Lightning Withstand Performance 390

8.1.3 Assessment for Lightning Withstand Performance

of 1000 kV UHV Lines in China 4168.1.4 Lightning Protection Measures for the UHVAC

Lines 4228.1.5 Analysis of Sideward Lightning Rod in Lightning

Protection of UHVAC Line 4278.2 Lightning Protection of the UHV Substations

(Switch Stations) 4358.2.1 Overview 4358.2.2 Assessment Methods for the Lightning Withstand

Performance of the UHV Substation 4368.2.3 Lightning Intruding Overvoltage Protection

of the UHV Substations 4518.2.4 Lightning Invasion Wave Protection Measures

for the UHV Substations 456References 459

9 Insulation Coordination of UHV Substations 461Fei Su, Hao Zhou and Yang Li

9.1 Basic Concept and Principles of Insulation Coordination 4629.2 Insulation Coordination Methods for UHV Power Grid 4639.3 Insulation Coordination of the UHV Substation 4679.3.1 Determination of Air Clearance of the UHV

Substation 4679.3.2 Selection of Insulation for the UHV Equipment 475References 484

10 Insulation Coordination of UHVAC Transmission Lines 485Hao Zhou, Fei Su and Jingzhe Yu

10.1 Selection of Type and Form of UHV Insulator Strings 48510.1.1 Comparison Among Three Different UHV

Transmission Line Insulators 48610.1.2 Selection of Type and Form of the UHV

Transmission Line Insulator Strings 49110.2 Methods to Determine the Number of the UHV

Transmission Line Insulators 49210.2.1 Selection of the Number of Insulators Based

on Power Frequency Voltage 49210.2.2 Selection of the Number of Insulators as Per

Switching Overvoltage 50810.2.3 Checking of the Number of Insulators

as per Lightning Overvoltage Requirements 50910.3 Determination of Air Clearances of the UHV Line 50910.3.1 Determination of Air Clearance Under Power

Frequency Voltage 515

10.3.2 Determination of Air Clearance Under Switching

Impulse Voltage 520

10.3.3 Determination of Air Clearance Under Lightning Impulse Voltage 537

10.3.4 Selection of Line’s Air Clearance of the UHV System Under Three Types of Overvoltage 542

10.3.5 Selection of Air Clearance of the UHV Lines in Various Countries 543

References 544

11 UHVAC Electrical Equipment 547

Xiande Hu, Yang Li and Xiujuan Chen 11.1 UHV Transformer 547

11.1.1 Status Quo of the UHV Transformers in China and Other Countries 548

11.1.2 Characteristics and Type Selection of the UHV Transformer 549

11.1.3 Main Parameters of the UHV Transformers Used for the UHVAC Demonstration Project 553

11.2 UHV Shunt Reactor 554

11.2.1 Structural Design 556

11.2.2 Insulation Design 558

11.2.3 Cooling Mode 558

11.2.4 Noise Control 559

11.2.5 UHV Controllable Shunt Reactor 560

11.3 UHV Instrument Transformer 561

11.3.1 Status Quo of the UHV Voltage Transformers and Current Transformers in China and Other Countries 561

11.3.2 UHV Voltage Transformer 562

11.3.3 UHV Current Transformer 564

11.3.4 Photoelectric UHV Instrument Transformer 565

11.4 UHV Arrester 566

11.4.1 Status Quo of the UHV Arresters in China and Other Countries 566

11.4.2 Characteristics of the UHV Arrester 566

11.4.3 Main Parameters of the UHV Arresters Used in the UHVAC Demonstration Projects 568

11.4.4 UHVAC Controllable Arrester 568

11.5 UHV Switchgear 572

11.5.1 Status Quo of the UHV Switchgear in China and Other Countries 572

11.5.2 Characteristics of UHV Switchgear 573

11.6 UHV Bushing 57611.6.1 Status Quo of UHV Bushing in China and Other

Countries 57611.6.2 Characteristics of the UHV Bushing 57711.7 UHV Series Compensation Device 57811.7.1 Status Quo of the UHV Series Compensation

Device in China and Other Countries 57811.7.2 Protection Mode of the UHV Series Compensation

Device 579References 579

12 UHV Power Frequency Electromagnetic Induction 581Baoju Li, Jidong Shi and Yijing Su

12.1 Induced Voltage and Current of the 1000 kV Double-Circuit

Line on the Same Tower 58212.1.1 Generation Mechanism and Four Different

Induction Parameters 58212.1.2 Simulation Calculation of Induced Voltage

and Current 58512.1.3 Analysis on Influence Factors of Induced

Voltage and Induced Current 58812.2 Induced Voltage and Induced Current on Overhead

Ground Wires of 1000 kV AC Transmission Line 58912.2.1 Induced Voltage and Induced Current on Overhead

Ground Wires of the UHV Single-Circuit Line 59112.2.2 Induced Voltage and Induced Current on Overhead

Ground Wires of the UHV Double-Circuit Line

on the Same Tower 59312.2.3 Selection of Insulation Gap and Withstand Voltage

of the UHV Overhead Insulated Conductors 59412.3 Power Frequency Electromagnetic Induction Influence

of the AC Line on the UHVDC Line Erected in Parallel

with It 59512.3.1 Power Frequency Electromagnetic Induction

by the UHVAC Line to the UHVDC Line Erected

in Parallel with It 59612.3.2 Influence Factors of the Electromagnetic Induction

by the AC Line to the DC Line Erected in Parallelwith It 59912.3.3 Comparative Analysis on Parallel Erection

of the UHV Single-Circuit and Double-Circuit

on the Same Tower of AC Line and the UHVDCLine 606

12.3.4 Comparative Analysis on Parallel Erection

of the EHV/UHVAC Transmission Line

and UHVDC Line 608

References 610

13 Electromagnetic Environment of UHVAC System 611

Xiao Zhang, Haiqing Lu, Yang Shen and Chuan He 13.1 Comparison Between Electromagnetic Environment of UHV and EHV Transmission Lines 612

13.2 Electromagnetic Environment of the UHVAC Transmission Line 614

13.2.1 Power Frequency Electric Field 614

13.2.2 Power Frequency Magnetic Field 622

13.2.3 Corona Loss 625

13.2.4 Radio Interference 629

13.2.5 Audible Noise 639

13.3 Optimized Phase Sequence Arrangement of the UHV Double-Circuit Transmission Line 645

13.3.1 Impact on Electromagnetic Environment 647

13.3.2 Impact on Natural Power 648

13.3.3 Impact on Unbalance Degree of Line 649

13.3.4 Impact on Lightning Withstand Performance 651

13.3.5 Impact on Induced Voltage and Current of Ground Wire 652

13.3.6 Recommended Optimal Phase Sequence for UHV Double-Circuit Line on the Same Tower 653

13.4 Safe Distance of UHV Transmission Line Over Buildings 654

13.4.1 Necessity of Research on Safe Distance 654

13.4.2 Calculation Methods and Simulation Models 655

13.4.3 Discussion on Influence Factors of Distorted Electric Field 658

13.4.4 Calculation of Safe Distance for UHV Transmission Line Over Building 666

13.5 Electromagnetic Environment of UHVAC Substation 667

13.5.1 Power Frequency Electric Field 667

13.5.2 Power Frequency Magnetic Field 668

13.5.3 Radio Interference 669

13.5.4 Noise 669

References 670

14 Principles and Configurations of UHVAC Protection 671

Laqin Ni, Jiyuan Li and Zhiyong Qiu 14.1 Basic Overview of UHVAC Protection 671

14.1.1 Basic Requirements of UHVAC Protection 671

14.1.2 Setting Principles of the UHVAC Protection 672

14.1.3 Characteristics of UHVAC Protection 674

14.2 Principles and Configurations of UHVAC Protection 683

14.2.1 Principles and Configurations of Line Protection 684

14.2.2 Principles and Configurations of CB Protection 695

14.2.3 Principles and Configurations of Busbar Protection 699

14.2.4 Principles and Configurations of Transformer Protection 703

14.2.5 Principles and Configurations of HV Shunt Reactor Protection 716

14.2.6 Principles and Configurations of LV Shunt Reactor and LV Capacitor Protection 722

References 725

Part III Direct Current 15 Basic Information and Calculation of Main Parameters for UHVDC Transmission System 729

Yang Shen, Xilei Chen and Yuting Qiu 15.1 Operating Principle of Converter 729

15.1.1 6-Pulse Converter 731

15.1.2 12-Pulse Converter 738

15.1.3 Double 12-Pulse Converter Connected in Series 739

15.2 Operating Modes of the UHVDC Transmission System 740

15.2.1 Selection of Voltage Level of UHVDC Converters 741

15.2.2 Operating Modes of UHVDC System 742

15.3 Calculation of Main Circuit Parameters of UHVDC System 748

15.3.1 Main Connection and Operation Modes of UHVDC Transmission Project 750

15.3.2 Rated Operating Parameters of DC System 751

15.3.3 Rated Operating Parameters of AC System 752

15.3.4 Parameters of DC Line 752

15.3.5 Equipment Parameters 753

15.3.6 Operating Parameters of DC System 763

References 765

16 Switching Overvoltage of UHVDC System 767

Dongju Wang, Hao Zhou and Jiyuan Li 16.1 Classification and Characteristics of Switching Overvoltage in UHVDC System 768

16.1.1 Classification of Switching Overvoltage 768

16.1.2 Characteristics of UHVDC Switching Overvoltage 769

16.1.3 Type of Faults Resulting in Switching Overvoltage 771

16.2 Simulation Model of DC System 772

16.2.1 Model for Main Circuit of DC System 772

16.2.2 Model of DC Control System 773

16.2.3 Scheme for Arrangement of Arresters in Converter Station 777

16.3 Switching Overvoltage at AC Side 778

16.3.1 Three-Phase Ground Fault and Clearing 780

16.3.2 Loss of AC Power Supply at the Inverter Side 782

16.3.3 Internal Overvoltage of AC Filters 786

16.4 Switching Overvoltage in Valve Hall 793

16.4.1 Switching Overvoltage on Valve Arrester V11/V1 795

16.4.2 Switching Overvoltage on Valve Arrester V12/V2 801

16.4.3 Switching Overvoltage on Valve Arrester V3 804

16.4.4 Switching Overvoltage on DC Converter Busbar Arrester 808

16.5 Switching Overvoltage in DC Field 811

16.5.1 Overvoltage on DC Pole Line 811

16.5.2 Overvoltage on Neutral Busbar 818

16.5.3 Internal Overvoltage of DC Filter 830

16.6 Monopolar Ground Fault Overvoltage of DC Line 836

16.6.1 Conditions for Simulation 837

16.6.2 Simulation Calculation Results 840

16.6.3 Analysis of Overvoltage Mechanism 847

16.6.4 Overvoltage Control and Protection Measures 854

References 855

17 Lightning Overvoltage of UHVDC Transmission System 857

Pan Dai, Hao Zhou and Bincai Zhao 17.1 Lightning Protection of UHVDC Transmission Line 858

17.1.1 Main Differences in Lightning Protection of AC and DC Lines 858

17.1.2 Characteristics of Lightning Withstand Performance for UHVDC Line 861

17.1.3 Analysis of Lightning Protection for the±800 kV UHVDC Transmission Line 862

17.2 Lightning Protection of UHVDC Converter Station 866

17.2.1 Protection Characteristics of Lightning Invasion

Wave for DC Converter Station 86617.2.2 Calculation Method for Lightning Intruding

Overvoltage in DC Converter Station 86817.2.3 Analysis for Overvoltage Protection of Lightning

Invasion Wave in±800 kV DC ConverterStation 874References 886

18 Insulation Coordination of UHVDC Converter Station 887Xilei Chen, Hao Zhou and Xu Deng

18.1 Basic Procedures for Determining the Insulation Level

of Equipment 88818.2 Overview of UHVDC Arrester 88918.2.1 Characteristics of UHVDC Arrester 88918.2.2 Definition of Basic Parameters of UHVDC

Arrester 89018.3 Configuration of Arresters in Converter Station 89118.3.1 Basic Principles for Configuration of Arresters 89118.3.2 Configuration Scheme of Arresters in Converter

Station 89218.3.3 Characteristics for Configuration of Arresters

in UHVDC Converter Station 89718.4 Selection of Parameters for UHVDC Arresters 89818.4.1 Basic Principles for Selection of Parameters

for Arresters 89818.4.2 Arresters at AC Side 89918.4.3 Arresters at DC Side 90118.4.4 Difference in Parameters of Arresters

for Converter Stations at Both Terminals 91118.5 Determination for Insulation Level of Converter Station’s

Equipment 91318.5.1 Method for Insulation Coordination of Converter

Station’s Equipment 91318.5.2 Insulation Margin 91318.5.3 Protection Level and Insulation Level 91518.6 Scheme for Separate Arrangement of Smoothing Reactors 91618.6.1 Economic and Technical Advantages of Separate

Arrangement of Smoothing Reactors 91818.6.2 Necessity for Adoption of Separate Arrangement

of Smoothing Reactors in UHVDC System 92318.7 Minimum Air Clearance in Converter Station 92418.7.1 Air Clearance Discharge Characteristic Test

of Pole Busbar in Converter Station 927

18.7.2 Equation Method for Design of Minimum Air

Clearance 93018.7.3 Non-standard Atmospheric Correction Method 93318.8 Polluted External Insulation of Converter Station 94218.8.1 Operation Experience of Polluted External

Insulation of Chinese±500 kV ConverterStations 94218.8.2 Selection of Post Insulators in Converter

Stations 94618.8.3 External Insulation Design of Post Insulators

in Converter Station 94718.8.4 Creepage Distance of DC Wall Bushing

in Converter Station 954References 956

19 Insulation Coordination of UHVDC Transmission Line 959Jidong Shi, Hao Zhou and Xu Deng

19.1 Selection of Type and Number of Insulators for UHVDC

Transmission Line 96019.1.1 Selection of Material and Umbrella Type

of Insulators 96019.1.2 Type Selection of Insulator Strings 96319.1.3 Determination of the Insulators’ Number 96419.1.4 Selection of Insulators in Icing Area 97419.2 Determination of Air Clearance for UHVDC

Transmission Line 97819.2.1 Determination of Air Clearance Under

DC Voltage 98319.2.2 Determination of Air Clearance Under

Switching Impulse 98419.2.3 Determination of Air Clearance Under

Lightning Impulse 98519.2.4 Code-Recommended Value and Engineering-

Applied Value for Air Clearance

of UHVDC Line 986References 987

20 Overvoltage Characteristics and Insulation Coordination

of UHVDC Converter Valves 989Kunpeng Zha, Xiaoguang Wei and Jie Liu

20.1 Analysis on Overvoltage Characteristics of Converter

Valves Under the Effect of Impulse Voltage 990

20.1.1 Extraction of Parasitic Capacitance of Converter

Valve System 99020.1.2 Analysis Model for Impulse Transient

of Converter Valve System 99420.1.3 Characteristics of Impulse Transient Overvoltage

of Converter Valve System 99420.2 Analysis on Overvoltage Characteristics of Converter

Valve Under Operating Condition 99620.2.1 Analysis on Turn-off Transient Overvoltage

of Converter Valve 99820.2.2 Physical Simulation Method 100020.2.3 Classical Method 100120.2.4 Time-Domain Circuit Method 100220.3 Overvoltage Protection of DC Transmission Converter

Valve and Its Design 100420.3.1 Strategy Selection for Insulation Coordination

of Converter Valves 100520.3.2 Overvoltage Protection Function of Gate

Electronic Circuit 100520.4 Study on Insulation Coordination for DC Transmission

Converter Valves 100720.4.1 Calculation Method for Creepage Distance 100720.4.2 Calculation Method for Air Clearance 1008References 1008

21 UHVDC Electrical Equipment 1009

Xu Deng, Anwen Xu and Yuting Qiu

21.1 Arrangement of UHVDC Equipment 100921.2 UHV Converter Valve 101221.2.1 Structure of UHV Converter Valve 101321.2.2 Characteristics of UHV Converter Valve 101621.2.3 Tests of UHV Converter Valve 101821.2.4 Manufacturing Level of UHV Converter

Valve 101821.3 UHV Converter Transformer 101921.3.1 Structure of UHV Converter Transformer 102021.3.2 Characteristics of UHV Converter Transformer 102121.3.3 Tests of UHV Converter Transformer 102421.3.4 Manufacturing Level of UHV Converter

Transformer 102521.4 UHV Smoothing Reactor 102621.4.1 Structure of UHV Smoothing Reactor 102621.4.2 Characteristics of UHV Smoothing Reactor 102821.4.3 Tests of UHV Smoothing Reactor 1030

21.4.4 Manufacturing Level of UHV Smoothing

Reactor 103021.5 UHVAC and DC Filters 103121.5.1 UHVAC Filter 103121.5.2 UHVDC Filter 103321.5.3 Tests of UHVAC/DC Filters 103621.5.4 Manufacturing Level of UHVAC/UHVDC

Filters 103621.6 UHVDC Arrester 103721.6.1 Type of UHVDC Arrester 103721.6.2 Characteristics of UHVDC Arrester 103821.6.3 Tests of UHVDC Arrester 104121.6.4 Manufacturing Level of UHVDC Arrester 104221.7 UHV Bushing 104221.7.1 Structure of UHV Bushing 104321.7.2 Characteristics of UHV Bushing 104521.7.3 Tests of UHV Bushing 104721.7.4 Manufacturing Level of UHV Bushing 104721.8 UHVDC Switchgear 104721.8.1 UHVDC Transfer Switch 104821.8.2 UHVDC Disconnector and Grounding Switch 105221.8.3 UHVDC Bypass Switch 105221.8.4 Tests of UHVDC Switchgear 105421.9 UHVDC Measuring Equipment 105421.9.1 UHVDC Voltage Measuring Equipment 105421.9.2 UHVDC Current Measuring Equipment 1055References 1056

22 Electromagnetic Environment of UHVDC System 1059Yiru Wan, Xiao Zhang and Jiyuan Li

22.1 Electromagnetic Environmental Issues of UHVDC

Transmission Line 106022.1.1 Electric Field Intensity and Ion Flow Density 106122.1.2 DC Magnetic Field 106422.1.3 Surface Electric Field Intensity of Conductor 106522.1.4 Radio Interference 107422.1.5 Audible Noise 107722.1.6 Corona Loss 108122.2 Electromagnetic Environmental Assessment of UHVDC

Transmission Lines 108422.2.1 Electric Field Intensity and Ion Flow Density 108522.2.2 Magnetic Induction Intensity 108722.2.3 Radio Interference 108722.2.4 Audible Noise 1089

22.3 Analysis on Electromagnetic Environmental Impact Factors

of UHVDC Transmission Line 109022.3.1 Influence of the Pole Conductor Height Above

the Ground 109022.3.2 Influence of the Interpolar Distance 109022.3.3 Influence of Bundling Spacing of Pole

Conductors 109222.3.4 Influence of the Number of Bundled

Sub-conductors 109222.3.5 Influence of Cross-Sectional Area of Pole

Conductors 109422.3.6 Influence of Altitude 109622.4 Measures for Improving the Electromagnetic Environment

of DC Transmission Lines 109622.5 Electromagnetic Environment of UHVDC Converter

Station 109822.5.1 Noise Sources of Converter Station 110022.5.2 Noise Control Indicators of Converter Station 110322.5.3 Noise Control Measures of Converter Station 1103References 1106

23 Comparison of Overvoltage and Insulation Coordination

of–800 kV and –1100 kV UHVDC Systems 1107Wenqian Qiu, Hao Zhou and Dongju Wang

23.1 System Parameters 110823.2 Configuration and Parameters of Arresters in Converter

Station 110923.2.1 Configuration of Arresters in Converter Station 110923.2.2 Basic Parameters of Arresters 111123.3 Analysis and Contrast of Overvoltage in Converter

Station 111123.3.1 Overvoltage at AC Side 111123.3.2 Overvoltage in Valve Hall 111423.3.3 Overvoltage at DC Line Side 112123.3.4 Neutral Busbar Overvoltage 112223.4 Insulation Coordination of±1100 kV UHVDC Power

Transmission System 112523.4.1 Configuration Scheme for Arresters in Converter

Station 112523.4.2 Influence of Short Circuit Impedance on Insulation

Level of Equipment 112823.4.3 Insulation Level of Equipment 112923.5 Discussion on Converter Combination for ±1100 kV

UHVDC System 1132

23.5.1 Discussion on Combination of±1100 kV

Converters 113223.5.2 Selection of Combination Scheme for Converters

of±1100 kV UHVDC System 1137References 1138

24 Principles and Configurations of UHVDC Protection 1139Taoxi Zhu

24.1 Overview of UHVDC Protection 113924.1.1 Basic Requirements of UHVDC Protection 113924.1.2 Action Result of UHVDC Protection 114024.1.3 Zone of UHVDC Protection 114324.1.4 Measuring Points of UHVDC Protection 114424.2 Principles and Configurations for UHVDC Protection 114724.2.1 Protection of Converter Area 114724.2.2 Protection of Polar Area 116324.2.3 Bipolar Area Protection 117024.2.4 Protection of DC Line Area 117724.2.5 Protection of DC Filter Area 118224.2.6 Protection of DC Switch 118824.2.7 Coordination Relation of DC Protection 119224.3 Difference Between UHVDC Protection and Conventional

DC Protection 119524.3.1 Configuration of Protective Devices 119524.3.2 Protection Configuration and Principle 1195References 1197Part IV Design of UHV Power System

25 Design of Ultra-High-Voltage Alternating Current

(UHVAC) Substation 1201Feng Qian, Wenqian Qiu, Jian Ding, Chunxiu An,

Hongbo Liu, Jianhua Chen and Yang Shen

25.1 Design Depth Requirements and Main Standards 120225.1.1 Design Depth Requirements 120225.1.2 Main Standards 120225.1.3 Key and Difficult Issues of Design 120325.2 Site Selection and General Layout 120325.2.1 Site Selection 120325.2.2 General Planning and Layout 120525.3 Main Electrical Connection 120625.4 Overvoltage Protection 120725.5 Minimum Air Clearance 121025.6 Insulation Level of Electrical Equipment 1210

25.7 Selection of Main Electrical Equipment 121225.7.1 Electrical Calculation 121225.7.2 Main Transformer 121225.7.3 Switchgear 121525.7.4 Voltage Transformer 121525.7.5 UHV Shunt Reactor 121625.8 UHV Distribution Equipment 121725.8.1 Classification and Design Principle of UHV

Distribution Equipment 121725.8.2 Minimum Safety Clearance Values

A, B, C, and D 122525.8.3 Main Features of UHV Distribution Equipment 122725.8.4 Size Determination of 1000 kV Distribution

Equipment 122725.9 Connection and Layout of Shunt Compensation Device 123025.9.1 Classification of Shunt Compensation Devices 123225.9.2 Grouping Capacity of Shunt Compensation

Devices 123225.9.3 Shunt Compensation Devices 123425.9.4 Layout of Shunt Compensation Devices 123525.10 Connection and Layout of Station-Service Power 123625.10.1 Main Design Principles 123625.10.2 Connection of Station-Service Power 123625.10.3 Station-Service Equipment and Layout 123625.10.4 Lighting and Maintenance 123725.11 General Plan and Vertical Layout 123725.11.1 General Layout Plan 123725.11.2 Vertical Layout 124025.11.3 Roads of Substation 124125.12 Main Buildings (Structures) 124125.12.1 Buildings of Substation 124125.12.2 UHV Substation Framework 124525.12.3 UHV GIS Equipment Foundation 125525.13 Secondary Electrical Connection 125825.13.1 Main Design Principles 125825.13.2 Computer-Based Monitoring System 125925.13.3 Element Protection 126125.13.4 System Protection 126325.13.5 System Communication 126725.13.6 Dispatching Automation System 126825.13.7 Electric Energy Metering and Billing System 1268

25.13.8 Operating Power Supply System and Others 126925.13.9 Equipment Status On-Line Monitoring System 1270References 1271

26 Design of UHVDC Converter Station 1273Zhichao Zhou, Xiaofei Ding, Wenqian Qiu, Jianhua Chen,

Chunxiu An and Sheng Liu

26.1 Site Selection and General Layout 127426.1.1 General Requirements 127426.1.2 General Layout 127426.1.3 Heavy-Duty Equipment Transport 127526.1.4 Water Supply to Converter Station 127626.1.5 Environmental Impact 127726.2 Main Electrical Connection 127826.2.1 Connection of Converter Unit 127826.2.2 Connection of DC Switchyard 127826.2.3 AC Switchyard Connection 128526.2.4 AC Filter Connection 128526.3 Overvoltage Protection of Converter Station 128626.4 Insulation Levels of Equipment 128726.5 Minimum Air Clearance Distance 129126.6 Selection of Main Electrical Equipment 129626.6.1 Calculation of Short-Circuit Current 129626.6.2 Converter Valve 130326.6.3 Converter Transformer 130626.6.4 Smoothing Reactor 130826.6.5 AC Filter and Shunt Capacitor 130926.6.6 DC Filter 131026.6.7 Other DC Equipment 131026.6.8 Wall Bushing 131426.7 Vertical Layout Design 131526.7.1 Main Tasks and Design Principles 131526.7.2 Vertical Layout with Slight Slope and Slope

Selection 131626.7.3 Vertical Layout with Terrace 131626.7.4 Vertical Layout of Buildings and Structures 131726.8 Power Distribution Device of UHVDC Converter Station 131726.8.1 Converter Area Layout 131826.8.2 DC Switchyard Arrangement 132926.8.3 Layout of AC Filter Yard 133226.8.4 Layout of AC Power Distribution Devices 134026.8.5 Summary of Electrical General Layout 134026.9 Buildings in Converter Station 134126.9.1 Main Buildings and Structures 1341

26.9.2 Valve Hall 134226.9.3 Control Building and Auxiliary Equipment

Building 134326.9.4 Indoor DC Yard 134426.9.5 GIS House 134426.9.6 Other Buildings 134426.9.7 Type of Structure 134426.10 Connection and Layout of Substation-Service Power 134526.11 Secondary System 134626.11.1 Control and Protection of AC and DC Systems 134626.11.2 AC Protection System and Safety and Stabilizing

Devices 135626.11.3 Dispatching Automation 135726.11.4 System Communication 1359References 1360

27 Design of Ultra-High-Voltage Alternating Current (UHVAC)

Power Transmission Lines 1361Jiamiao Chen, Wenqian Qiu, Feng Pan and Gang Song

27.1 Design Basis 136327.2 Line Routes 136327.3 Design Meteorological Conditions 136427.3.1 Principles of Selection 136427.3.2 Basic Wind Speed 136427.3.3 Design Icing 136627.4 Selection of Conductor and Ground Wire of AC Lines 136727.4.1 Main Parameters for Conductor Selection 136827.4.2 Conductor Cross-Section and Bundled

Configuration 137227.4.3 Phase-Sequence Arrangement of the Double-

Circuit Conductors 137427.4.4 Application of Expanded Conductors 137627.4.5 Selection of Ground Wire and OPGW Optical

Cable 137927.5 Insulation Coordination Design of AC Transmission Line 138227.5.1 Type Selection of Insulators 138327.5.2 Selection of the Number of Pieces of Insulator

Strings 138727.5.3 Air Clearance at Tower Head 139027.5.4 Lightning Protection and Grounding Design 139227.6 Design of AC Line Insulator Strings and Fittings 139427.6.1 Basic Principles 139427.6.2 Safety Factor 139527.6.3 Suspension Insulator String of Conductor 1396

27.6.4 Strain Insulator String of Conductor 139827.6.5 Jumper Fitting String of Strain Tower 139927.6.6 Main Fittings 140227.7 Conductor Transposition Design for AC Line 140627.7.1 Main Content of Conductor Transposition

Design 140727.7.2 Determination of Unbalance Factor Limits 140727.7.3 Calculation of Unbalance Factor for Power

Transmission Line 140827.7.4 Selection of Transposition Ways 141027.8 Tower Design for UHV Transmission Line 141227.8.1 Types and Characteristics of Tower 141227.8.2 Tower Loads and Combinations 141727.8.3 Materials of Tower 141827.8.4 Optimization Design of Tower Structure 142127.8.5 Issues to Be Noticed in the Design of Tower

Structure 1425References 1427

28 Design of UHVDC Transmission Lines 1429Jiamiao Chen, Wenqian Qiu, Jia Tao, Yong Guo and Jianfei Chen

28.1 Selection of Conductors for DC Line 143028.1.1 Main Principles for Conductor Selection 143028.1.2 Conductor Section and Bundle Configuration 143128.1.3 Main Electrical Properties of Conductor 143328.1.4 Selection of Ground Wire Types 144028.2 Insulation Coordination Design of DC Line 144028.2.1 Pollution Investigation and Polluted Area

Classification 144128.2.2 Insulator Types 144228.2.3 Selection of the Number of Insulators

for the Insulator Strings 144528.2.4 Air Clearance of Tower Head 145228.3 Design of Insulator Strings and Fittings of DC Line 145328.3.1 Insulator String of Conductor 145328.3.2 Selection of Main Fittings 145728.4 Clearance of Conductor to Ground for DC Line 145928.4.1 Minimum Clearance of Conductor to Ground 145928.4.2 Relation Between Clearance of Conductor to

Ground and Environmental Climate 146028.5 Tower Design of DC Line 146128.5.1 Tower Types of DC Line 146128.5.2 Structural Characteristics of Towers

for DC Line 1463

28.5.3 Tower Load and Combination 146528.5.4 Tower Materials of DC Line 146528.5.5 Issues to Be Noticed in Tower Design 146728.6 Foundation Design for DC Line 146928.6.1 Common Foundation Types 146928.6.2 Issues to Be Noticed in Foundation Design 147028.6.3 Treatment Measures for Foundations Under

Special Geological Conditions 147328.6.4 Mechanical Construction of Foundations 1474References 1475

This book systematically introduces the key technical issues existing in theultra-high-voltage (UHV) AC and DC power transmission The whole book con-sists of four parts, among which, Part I provides an overview of the development

of the UHV power transmission and the system characteristics and economythereof Part II mainly elaborates the key technical issues involved in the UHVACsystem, including power frequency overvoltage of UHV lines, secondary arc cur-rent of UHVAC system, switching overvoltage of UHVAC system, very fasttransient overvoltage (VFTO) of UHVAC system, lightning protection of UHVACsystem, insulation coordination of UHV substation, insulation coordination ofUHVAC transmission line, UHVAC electrical equipment, UHV power frequencyelectromagnetic induction and electromagnetic environment of UHVAC system,protection principles, and configuration of UHVAC system Part III mainly elab-orates the key technologies for the UHVDC system, including UHVDC systemfoundation and main parameter calculation, switching overvoltage of UHVDCsystem, lightning overvoltage of UHVDC transmission system, insulation coordi-nation of UHVDC converter station, external insulation coordination of UHVDCtransmission line, overvoltage characteristics and insulation coordination ofUHVDC converter valve, UHVDC electrical equipment, electromagnetic environ-ment of UHVDC system and comparison of overvoltage and insulation coordina-tion of ±800 kV and ±1100 kV UHVDC systems, protection principles, andconfiguration of UHVDC system Part IV gives a main introduction to the design

of the UHVAC substation and UHVDC converter station as well as AC and DCpower transmission lines

This book not only can be applied as the specialized course material and erence book for the electrical discipline undergraduates and postgraduates of seniorcolleges to allow the teachers and students of senior colleges to understand theUHVAC and UHVDC power transmission technology, but also can be applied asthe reference book for the technicians engaging in the UHV power transmissiontheoretical research, planning and design, operation and maintenance, and otherworks

ref-xxxiii

This book is supported by the Basic Research on Electromagnetic andInsulation Characteristics of UHVAC and DC Power Transmission System(2011CB209400), a major project under the National Key Basic ResearchDevelopment Program of China (973 Program), and also supported by theNational Science and Technology Academic Publication Fund and ZhejiangUniversity—Zhejiang Electric Power Design Institute Cooperation Center.

Part I Overview

The UHV power transmission system refers to the transmission system at voltagelevel of AC 1000 kV, DC±750 kV and above The fast growth of electrical loadand the urgent needs in high-capacity and long-distance power transmission directlypromote the rapid planning and construction of the UHV power transmissionprojects in China Up to august 2017, six 1000 kV UHVAC power transmissionlines and nine±800 kV UHVDC power transmission lines have been built and putinto operation There are still another 1000 kV UHVAC power transmission lineand the other four ±800 kV UHVDC power transmission lines will be put intooperation at the end of 2017 Moreover, one ±1100 kV UHVDC power trans-mission line is being built and will be put into operation in 2018 The UHV powertransmission technology will greatly promote the sustainable development ofChina's power industry and energy industry, and have a positive and profoundimpact on the construction of power technology innovation, energy guaranteesystem and global energy internet in the world.This section first discusses theselection of voltage levels of the UHVAC and UHVDC power grid and thedevelopment of UHV power transmission technology around the world, and thenintroduces the UHV planning and development in China, and finally conductsdiscussion on the characteristics and economy of UHV system

Development of UHV Power Transmission

Ke Sun, Dongju Wang, Sha Li and Haifeng Qiu

With the rapid development of China’s economy and the rapid increase in the demandfor electricity by the whole society, the power transmission technology of the con-ventional EHV voltage level cannot meet the growing demand for electricity, thus it isnecessary to develop the power transmission technology of higher voltage level Theadoption of the UHV power transmission technology not only can effectively solve therapid growth of China’s growing demand for electricity, but also makes thelong-distance and high-capacity power transmission become more economic China’sexisting UHVAC and UHVDC power transmission projects are all developed underthis background This chapter begins with the introduction of the development of the

AC and DC power grid’s voltage level from low voltage to high, and, additionally,focuses on the selection of UHVAC and UHVDC power transmission voltage levelsand the development of UHV power transmission technology in the world

© Zhejiang University Press, Hangzhou and Springer-Verlag GmbH Germany 2018

H Zhou et al (eds.), Ultra-high Voltage AC/DC Power Transmission,

Advanced Topics in Science and Technology in China,

https://doi.org/10.1007/978-3-662-54575-1_1

3

1.1 UHV Power Transmission

In 1882, Deprez, a French physicist, by making use of a DC generator in a coalmine under DC voltage of 2 kV, and power of 1.5 kW and along the telegraph line

of 57 km, successfully sent the electrical energy to an international exhibition held

in Munich, completing the long-distance power transmissionfirst ever in humanhistory by the way of DC power transmission This DC power transmission modewas once very popular But because of the DC motor’s complex structure, poorreliability, and the great difficulty in the design and manufacturing technology oflarge-capacity and high-voltage DC motor, under the circumstances at that time, thepower transmission voltage, capacity, and distance could only be increased byconnecting multiple generators in series In 1889, in France, a high voltage wasobtained by connecting DC generators in series, and a 230 km DC power trans-mission line was built from Moutiers to Lyon, whose transmission voltage andtransmission power were 125 kV and 20 MW, respectively Under the technicalconditions at that time, it was quite difficult to achieve the power transmission withlonger distance and larger capacity using the DC power transmission mode So thepeople began to turn to study the use of AC power transmission mode, by which thetransmission voltage could be more easily and rapidly improved, thus achieving thepower transmission with longer distance and larger capacity

In 1888, on the River Thames in London, the large-scale AC power stationdesigned by Ferranti began to transmit power The copper-core cables were used bythe power station to send the 10 kV single-phase AC power to the urban substation

10 km away, where the power was transformed from 10 kV to 2500 V and thendistributed to the secondary transformers in all blocks, where the power was oncemore transformed to 100 V for lighting by users In 1889, Dolivo–Dobrovolsky ofRussia had developed the first three-phase AC generator with power of 100 W,which was used widely in Germany and the US In this context, the three-phasehigh-voltage AC power transmission mode got rapid promotion worldwide.Through the AC power transmission mode, the transformer could be used toimprove the transmission voltage to achieve power transmission with longer dis-tance and larger capacity easily So the AC power transmission, with obviouseconomic and technical advantages displayed, got continued rapid development,gradually became common and replaced the original DC power transmission, andeventually became the transmission mode with absolute dominance in thefield ofelectric energy transmission Since the 10 kV AC transmission mode was used byscientists in 1888, the transmission voltage was increased to 33 kV with the help of

AC transformer in 1898, increased to the high voltage of 110 and 230 kV in 1907and 1923, respectively, increased to the extra high voltage of 380, 500, and 735 kV,respectively, in 1952, 1959, and 1965, and even increased to the ultrahigh voltage

of 1150 kV by the former Soviet Union in 1985 [1–3] Since the first 500 kVEHVAC power transmission line in China, Pingdingshan–Wuhan 500 kV EHVAC

power transmission line, was put into operation in 1981, the 500 kV EHV powergrid had gradually become the main grid framework of the major regions; thefirst

750 kV EHV power transmission line from Guanting, Qinghai to Lanzhou, Gansu

in China was built in the northwest power grid in 2005, and now the 750 kV powergrid is becoming the main grid framework in the northwest power grid; in 2009, the

1000 kV Southeast Shanxi–Nanyang–Jingmen power transmission line, China’sfirst UHVAC demonstration project, was put into operation In 2013, the Huainan–Shanghai 1000 kV UHV double-circuit AC power transmission line project wascompleted Subsequently, in December 2014, the North Zhejiang–Fuzhou 1000 kVUHV double-circuit AC power transmission line project was put into operation Inaddition, a number of other 1000 kV UHVAC power transmission projects areunder planning and construction

Since the AC power transmission was applied in 1890, the development of DCpower transmission had been nearly halted for more than half a century until theSweden Gotland DC power transmission project, the DC submarine cable powertransmission system adopting mercury arc valve conversion mode, was put intooperation in 1954 However, due to the poor reliability of mercury arc valveconversion mode, it did not effectively promote the DC power transmission mode tomove forward Since the 1970s, with the rapid development of power electronicsand microelectronics technologies, new high-voltage and large-power thyristoremerged Because the thyristor valve had no inverse arc faults and was much easierand more convenient than the mercury arc valve in manufacturing, testing, oper-ation, maintenance and repair, it effectively improved the operating performanceand reliability of DC power transmission and quickly got good application in the

DC power transmission projects, greatly promoting the development of DC powertransmission technology [4] In 1970, based on the original Gotland DC powertransmission project, Swedenfirst expanded it by the construction of the thyristorvalve demonstration project with DC voltage of 50 kV and transmission power of

10 MW In 1972, the Eel River DC Back-to-Back Project (2 80 kV,

2 160 MW), the first project fully adopting thyristor conversion in the world,was put into operation in Canada Because the DC power transmission hasprominent and special advantages in such fields as the long-distance andlarge-capacity overhead power transmission line, submarine cable power trans-mission and AC system back-to-back link, with the help of the new thyristor valves,the DC power transmission, thereafter, once again got rapid development in thewhole world The new DC power transmission projects making use of thyristorvalves constantly emerged and the DC transmission voltage constantly wasincreased By 2003, a total of 65 thyristor valve projects were constructed and putinto operation in the world, among which a considerable part was importantlong-distance EHVDC power transmission projects with transmission voltage of

±500 to ±600 kV and a few were multi-terminal DC power transmission projects

In China, since the Gezhouba–Shanghai ±500 kV DC power transmission projectwas put into operation in 1990, several ±500 kV EHVDC power transmissionprojects had been successively built and put into operation China built the Yunnan(Chuxiong)–Guangzhou (Suidong) ±800 kV DC power transmission project and

the Xiangjiaba (Fulong)–Shanghai (Fengxian) ±800 kV DC power transmissionproject in 2010, completed the Ningxia (Ningdong)–Shandong (Qingdao) ±660 kV

DC power transmission project in 2011, completed the Sichuan Jinping (Yulong)–Jiangsu Sunan (Tongli) ±800 kV DC power transmission project in 2012, com-pleted the Yunnan (Puer)–Guangdong (Jiangmen) ±800 kV DC power transmis-sion project (or called as Nuozadu DC power transmission project) in 2013, andcompleted the South Hami (South Hami)–Zhengzhou (Zhengzhou) and Xiluodu(Shuanglong)–West Zhejiang (Jinhua) ±800 kV DC power transmission projects in

2014 Currently, China has several±800 kV UHVDC power transmission projectsunder construction and preparation The bipolar single-circuit DC power trans-mission project with voltage grade of ±1100 kV has been researched anddemonstrated, and the design preparation of the pre-phase engineering has beenconducted depending on the East Junggar Basin–East China project

The basic purpose of the development of power transmission technology is toimprove transmission capacity and reduce line losses Increasing the transmissionvoltage is an effective way to improve the transmission capacity and also aneffective way to reduce line losses Thus, the whole history of the development ofpower transmission technology is almost the process to continuously improve thetransmission voltage level so as to constantly increase the transmission power andconstantly extend the transmission distance For the division of transmission volt-age levels, there are many different methods prescribed For AC power transmis-sion, in combination with scientific researches and practical applications, thevoltage levels are currently often divided as follows: the voltage level of 10, 20, and

35 kV is referred to as the distribution voltage or medium voltage (including thevoltage level of 66 kV which, however, is applied only in a few countries andregions); the voltage level of 110–220 kV is referred to as high voltage; the voltagelevel above 220 kV and below 1000 kV is referred to as extra-high voltage (EHV),mainly including 330, 500, and 750 kV; the voltage level of 1000 kV and above isreferred to as ultrahigh voltage (UHV) The situation for DC power transmission isdifferent to some extent According to the American National Standards, the voltagelevel above±100 kV is referred to as high voltage, the voltage level of ±500 and

±600 kV is referred to as EHV and the voltage level above ±600 kV is referred to

as UHV; the Soviet studies suggest that the voltage level of±750 kV and above isreferred to as UHV; in China, the voltage level of±800 kV and above is normallydeemed as UHV

Table1.1shows the overview of the development of AC transmission voltagelevels, and Table1.2shows the overview of the development of DC transmissionvoltage levels

The emergence of new transmission voltage levels depends on many factors:first, the need for long-distance and large-capacity transmission, and second the

consideration in such aspects as transmission technology, economic efficiency andenvironmental impact The development of a new voltage level needs the com-pletion of many works, such as selection of voltage values, determination ofinsulation levels, development of equipment and construction of test lines, so that itcan be compatible with the original voltage levels and can adapt to the needs forpower development in the next two decades or longer Each country has differenteconomic conditions, resource distribution and geographical conditions, so thevoltage level sequence applied is different, resulting in the formation of different

AC and DC transmission voltage level sequences

The different AC transmission voltage level sequences used in some of the majorcountries in the world are as shown in Table1.3

Since Sweden’s Gotland DC power transmission project was put into operation

in 1954, hundreds of DC power transmission projects had been built and put intooperation around the world Currently, the rated voltage of DC power transmissionproject has not yet formed into standard voltage level sequence as same as ACpower transmission, and the rated voltage of each specific DC power transmissionproject is determined according to the actual situations, which causes that theequipment design, production and selection cannot be generalized and scaled,increasing the project cost, reducing the maintainability of equipment and bringingdifficulties for production and operation The DC power transmission projectsinclude overhead lines, cable lines and back-to-back projects and many other types.During the conversion of mercury arc valves prior to the industrial application ofthyristor products, the rated voltage of DC power transmission projects is alsolimited by the withstand voltage of mercury arc valve and other factors After theemergence of thyristor converters, they commonly adopt the structure of elementsconnected in series It is theoretically allowable to use any rated voltage, whichdoes not increase the difficulty in design and manufacture of the converter, resulting

in the various rated voltages involved in current DC power transmission projects

At present, the DC rated voltages (kV) of DC power transmission projects in theworld having been put into operation include:±17, ±25, ±50, ±70, ±80, ±82,