Chapter 7
R&D on Global Energy Interconnection and Practice
Abstract
The boundary of global energy innovations has been constantly pushed forward against a background of technical exploration and engineering practice. The global energy network, focused on UHV grids and clean energy generation, is regarded as a major breakthrough and integrated innovation in modern energy and electric power technologies. Over the years, domestic and overseas studies and engineering practices on UHV grids, smart grids, clean energy, and supergrid interconnections, especially China’s success in building the robust smart grid, have laid a solid foundation for developing a global network of energy interconnections.
Keywords
global energy interconnection
practice
UHV
robust smart grid
clean energy
interconnected grid
strategic planning
project engineering
standards formulation
1. Practice in China
Since the twenty-first century, China’s rapidly developing economy and increasing energy demands have provided a strong impetus to the construction of large-scale power bases of coal-fired, hydro, nuclear, and renewable energy, in particular wind and solar generation. Meanwhile, the geographically reverse distribution of China’s energy resources and energy consumption creates the urgent demand for optimized allocations of resources over extensive areas and on a large scale. This calls for leveraging the strengths of robust smart grids in high capacity and long-distance transmission to realize the intensive development of power bases across different energy types, and the export of energy for integration. In recent years, China has vigorously promoted the development of UHV, smart grid technologies, and clean energy, focusing efforts on technological innovation, standard setting, strategic planning, and project construction in respect of robust smart grids, providing technological and other conditions conducive to the development of the global energy network.
1.1. Technological Innovation
1.1.1. UHV Technologies
UHV technologies cover UHV AC and DC transmission technologies, representing the state-of-the-art level of grid technologies in the world. Since the development of UHV was fully launched in 2004, achievements have been made on the technology and equipment fronts, fulfilling the brand propositions of “Made in China” and “Led by China.” As at the end of 2014, SGCC attained a total of 705 patents in UHV transmission technology, including 318 invention patents, 387 utility models, and appearance design patents. According to Klaus Wucherer, former president of the International Electrotechnical Commission (IEC), China now boasts of a world-leading UHV transmission technology, and the country’s UHV AC voltage standards (as international standard voltage) will be promoted all over the world.
1.1.1.1. UHV AC Transmission Technologies
As early as 1986, China carried out preliminary discussions and feasibility studies on UHV AC transmission. In 2004, research on key UHV AC transmission technology was conducted, setting a technological framework. In 2006, UHV AC transmission technology was applied in engineering projects. Work on pilot demonstration projects commenced in the same year, and was subsequently commissioned in 2009. Currently, China has fully mastered UHV AC transmission technology.
Key technologies of UHV AC transmission: Through SGCC’s proprietary innovations and joint explorations, breakthroughs have been made in the core technologies of system voltage control, secondary arc current suppression, external insulation coordination, as well as electromagnetic environment control, leading China to attain world leadership in this technological area. For system voltage control, measures such as over-voltage amplitude control, protection intertrip, high performance arrester, closing resistor, earth wire optimization, as well as reactive power control have been adopted to attain control of power frequency, operation, lightning, and system operation over-voltage, respectively. For secondary arc current suppression, small reactance components are installed on the neutral points of UHV electric reactors, to effectively control secondary arc currents, elevate single-phase reclosing success rates, and ensure system supply reliability. For external insulation coordination, measures toward deep suppression of over-voltage level, utilization of the composite insulator and sleeve, and simulation of high altitude insulation characteristics have been pursued to solve problems such as substantially larger external insulation scale, noticeably lower insulation, and voltage withstanding capacity with higher pollution levels and altitudes, to significantly improve system economics, while ensuring security. For electromagnetic environment control, a series of technologies and measures such as complicated multiconductor system power frequency electric field model simulation, wire arrangement optimization, and armor clamp corona control, to effectively reduce the impact of noises, radio disturbance, and also achieve environment friendliness (Fig. 7.1).
Figure 7.1 UHV AC (1000 kV) Transmission Lines and Towers
Key technologies of UHV AC equipment: Equipment is crucial for UHV development. SGCC, together with electrical equipment manufacturers, has developed a proprietary design of the world’s first UHV AC transformer (Fig. 7.2) at a rated voltage of 1000 kV and with a rated capacity of 3 GVA, by successfully mastering the key technologies of transformer insulation structural design, leakage flux control, and local overheating prevention. Gas insulated switchgear has also been developed through breakthroughs in design technologies for UHV AC breaker operating mechanisms and arc-extinguishing chambers (Fig. 7.3). Successful research and development (R&D) has led to the creation of UHV AC shunt reactors (Fig. 7.4) with the world’s highest single-phase capacity (320 Mvar) to solve technological problems such as the control of leakage flux, temperature rise, noise and vibration control under high voltage and high capacity conditions. In addition, UHV arresters, capacitor voltage transformers, UHV insulators, and more reliable and stable complete-set secondary equipment of UHV systems have been developed for application in regions of medium and high level pollution.
Figure 7.2 UHV AC (1000 kV) Transformer
Figure 7.3 UHV AC (1000 kV) Breaker
Figure 7.4 UHV AC (1000 kV) Shunt Reactors
1.1.1.2. UHV DC Transmission Technology
In 2004, China embarked on comprehensive and in-depth research on ±800 kV UHV DC transmission engineering technology, achieving all-round breakthroughs in HV DC, high current, high power transmission technologies, and equipment.
Key technologies of UHV DC transmission: Like UHV AC transmission, UHV DC transmission has encountered unprecedented challenges in over-voltage and insulation coordination, external insulation configuration, electromagnetic environment and noise control, DC system design, and other technologies. Through continuous research, trial and technological innovation, all these problems have now been resolved. For over-voltage and insulation coordination, through the calculations, by full simulation, of DC transmission system converter stations and the over-voltage characteristics and levels under different operation and fault conditions along transmission lines, technological solutions to over-voltage problems have been proposed to rationally deploy arresters, optimize arrester parameters, and evenly distribute smoothing reactors. For external insulation configuration, through experiments and studies, the long air gap discharge characteristics of transmission lines, the characteristics of real electrode air gap discharges and corresponding altitude correction coefficients, insulator pollution and icing flashover characteristics, and corresponding altitude correction coefficients have been obtained and successfully applied to external insulation configuration in a UHV DC transmission project. For electromagnetic environment and noise control, with wire types, minimum wire heights, and minimum corridor widths confirmed through studies, knowledge has been acquired of transverse distribution and the law of change, in various electromagnetic environment factors, leading to proposals for the optimal polar wire arrangement in electromagnetic environments and for optimized configuration of converter stations to effectively reduce the impact of engineering work on the environment. For DC system design, after confirmation of UHV DC system rated voltages, rated currents, transmission power, and other key parameters through studies, complete design plans have been proposed for the first time, and world-class standards successfully achieved for proprietary system integration in UHV DC transmission.
Key technologies of UHV DC equipment: In terms of components, the major parameters of 6-in. thyristors have been determined through studies. The development of special monocrystalline silicon pretreatment processes has resolved key technological problems of impurity diffusion uniformity, chip thickness uniformity, chip parameters uniformity, as well as chip deformation control, caused by the expansion of thyristor chip size to 6 in. This has led to the successful development of 6-in. thyristors (Fig. 7.5) and the fulfilment of the goal of creating high current and high blocking voltage thyristors with 6-in. monocrystalline silicon materials. For equipment, a ±800 kV UHV DC transmission converter transformer (Fig. 7.6), with the world’s highest voltage and capacity levels, has been successfully developed, where problems such as local discharge control, leakage flux, harmonic wave, and temperature rise control have been resolved by adopting advanced regulating winding connection methods. UHV DC transmission converter valves (Fig. 7.7) with the highest capacity have been produced, after solving design problems of insulation structures and optimizing valve-side sleeves and outgoing line devices, with the development of DC wall bushing and disconnectors with the world’s highest flow capability. In addition, ±800 kV smoothing reactors, ±800 kV DC and AC field equipment, ±800 kV control and protection equipment, wires with 1000 mm2 and higher sections, ±800 kV DC transmission line insulators, and complete sets of ±800 kV DC wire armor clamps (Fig. 7.8) have been developed.
Figure 7.5 Thyristor (6 in.)for ±800 kV UHV DC Transmission Lines
Figure 7.6 UHV DC (±800 kV) Transmission Converter Transformer
Figure 7.7 UHV DC (±800 kV) Transmission Converter Valve
Figure 7.8 UHV DC (±800 kV) Transmission Lines and Towers
1.1.2. Smart Grid Technology
Technological innovation in smart grids has contributed to the improvement of safety, adaptability, economics, and interactivity in power system operations. China has realized all-round breakthroughs in smart-grid equipment monitoring, system operation, smart interactivity, information and communication, and other technologies. As at the end of 2014, SGCC owned 11,312 patents related to smart grids, including 1,622 invention patents and 9,690 utility model, and appearance design patents.
Equipment monitoring: Monitoring and control of key equipment of all components of power system can provide real-time and complete information on equipment operation conditions, offering support to the dynamic optimization of equipment operations and efficiency improvement. Master station and terminal equipment for monitoring transmission and transformation equipment conditions have been developed (Fig. 7.9), with work started on equipment condition evaluation, condition-based monitoring and risk prewarning to achieve controllability of key transmission and transformation equipment. Breakthroughs have also been made in robot and UAV smart inspection technologies (Fig. 7.10), resulting in improved operational safety of equipment. Successful development of integrated monitoring systems at the substation level, auxiliary function-level control, and fully digitalized protection monitoring systems, has realized integrated online monitoring and self-diagnosis for substation equipment, testing of monitoring and automatic devices, as well as automatic monitoring of operation environments. Extensive application of unified support systems for smart power distribution terminals and online risk evaluation and prewarning systems at the distribution level has been realized.
Figure 7.9 Online Monitoring System for Transmission Lines
Figure 7.10 Robot on Patrol Duty in Smart Substation
System operation: To achieve smart operation and dispatch by gaining a full understanding of grid operation conditions and improving grid operational safety and stability through online analysis, safety evaluation, forecasting and prewarning, as well as dispatch control. For super-grid operation, technological breakthroughs have been made to achieve online, sophisticated, integrated, and practical smart dispatch operations. By “online” we mean online tracking based on the three dimensions of time, space, and business to realize panoramic monitoring, smart warning and active security and defense of all aspects of dispatch and production. By “sophisticated” we mean the automatic and optimized formulation of large-scale, multitarget and multiple-time dispatch programs for safe, economical, and integrated operation to meet complicated constraints, as well as all round safety and stability checks covering stable, dynamic, and transient conditions. By “integrated” we mean the realization of upper and lower linkages, and coordinated operation across different levels of dispatch to form a distributed, integrated support system for smart dispatch technology and effectively support the integrated operation of UHV large grids. By “practical” we mean efforts to perfect fundamental data, improve online application in terms of system operation, and promote the application level of day-ahead dispatch plans and safety checks. For distribution grid operation, important breakthroughs have been made in self-recovery control, smart distribution terminals, distributed power access, and other areas. Open distribution automation systems and smart distribution terminals have also been developed to realize information sharing and application integration of distribution automation and related systems. R&D work on the control technologies for distributed power generation/energy storage and microgrid access and coordination has played a vital role in improving power supply reliability and peak shaving/valley filling.
Smart interactivity: Multiple technological measures have been adopted to realize information sharing and interaction between systems and users. Breakthroughs have been made in smart meters, metering system monitoring, electric car charging, smart buildings, smart communities, and smart parks, leading to the development of a smart, interactive fundamental platform to realize noticeable improvements in smart power services. Smart meters have been promoted on a full scale and a system for collecting information on electricity consumption established, covering all electricity users and metering points. Online monitoring has also been achieved, with important information on customer-side power load, consumption and voltage collected in real time. Smart power service systems for smart communities (buildings) and demonstration projects on smart power consumption have been accomplished, realizing real-time and interactive response between smart grids and users. Chargers, charging piles, battery swapping, and other equipment have been developed, with a platform for monitoring electric car operations built to form a standard operation management system for electric car–smart recharging/swapping networks. As a result, an exchange of information has been achieved between battery charging/swapping stations and vehicles.
Communication and information: A communication and information platform is a basic foundation for achieving and applying smart technologies on all fronts. China has made breakthroughs in different aspects of power communication and power information technologies. In power communication technology, a high capacity backbone optical transmission network, a demonstrative project on the ice resistance of optical fiber composite overhead ground wire, and a demonstrative project on the electricity-based Internet of Things have been set up. Through the development of special electricity communication chips, breakthroughs have been made in packet transport network, Ethernet passive optical network, industrial Ethernet, power line carrier communication, wireless private and public network communication, as well as special optical fiber composite cable technologies (Fig. 7.11). A technology system for next-generation flip networks has been proposed, with a management system for power telecommunication networks developed and widely applied. A platform for power telecommunication network simulation has been developed and quantum communication technology introduced into the electricity industry for the first time. On the power information technology front, all-round breakthroughs have been made in R&D and application of information technologies in different segments of a smart grid. A host of smart-grid information systems covering transmission, transformation condition monitoring, and mobile operations have been put online. A unitary video monitoring system and a geographic information service system have been developed. The application of information systems covers planning, construction, operation, maintenance, and marketing. An integrated information and dispatch operation system has been built, covering the headquarters, failover centers, and provincial companies. Smart-grid information security protection plans have been announced, with the grade protection evaluation of secondary-system information security protection and management information systems completed for grids higher than Grade III.
Figure 7.11 Section of Optical Fiber Composite LV Cable
1.1.3. Clean Energy Technology
Clean energy technology is an important tool to ensure clean energy substitution. China has developed a host of innovations and applications in clean power generation and operation technologies, giving a strong impetus to large-scale exploration and integration of clean energy.
Key technologies of large-scale wind power dispatch: Breakthroughs have been made in key technologies such as wind power forecasts, dispatch technology for optimal coordination of wind power and other power, and the application of wind power in peak load shifting. This has resulted in the achievement of online wind-power capacity assessment, wind power day-ahead, and intraday scheduling adjustments, and the evaluation of wind power grid integration performance. In the course of operation, wind power is incorporated into start-up arrangements and also the rolling optimization of thermal power plant start-ups, to realize maximum accommodation of fluctuating wind power within its operation range and ensure system operational safety.
Large-scale photovoltaic power grid integration and operation technologies: Through R&D of key technologies for photovoltaic power generation, including output forecasting, operation monitoring, and operation control, all-weather predictions, across different times and spaces based on numerical weather forecasts have been achieved. Closed-loop control of the power of large photovoltaic power stations has been realized. Rolling optimization of day-ahead and intraday scheduling of high penetration photovoltaic power grids has been made possible. Problems such as momentary output fluctuations have been resolved, a hierarchical photovoltaic power generation control system established, and the automatic and smooth regulation of the active and reactive output of photovoltaic power generation realized.
New energy-based generation output forecasting and operation monitoring: A technology system for forecasting and monitoring new energy-based generation output has been established. For new energy-based generation output forecasting, technology research and system development has been launched for projecting wind and photovoltaic power output based on numerical weather forecasts, and SGCC operation center for numerical weather forecasts established. The technology for short-term and super-short-term forecasting of wind power output has been acquired, and an output forecasting system that embodies independent intellectual property rights has been developed. A wind power generation output forecasting system, with an accuracy of 88%, has been deployed at provincial-level dispatch centers. Technology research has been carried out on short-term and super-short-term forecasting, with an accuracy of 90%, of photovoltaic power output based on numerical weather forecasts and satellite and foundation cloud pictures. This technology is now in demonstration application in a number of provincial-level grids. A grid-based forecasting technology for distributed photovoltaic power generation has been developed and applied in many parts of China. For new energy operation monitoring, advanced coordination of new energy power generation and transmission has been achieved and breakthroughs in wind power operation online monitoring made (Fig. 7.12). Through efforts in building wind power operation monitoring and automation systems, wide-area panoramic presentation and monitoring has been realized of wind farm weather information as well as wind-turbine information on active power, reactive power, voltage, current, and operation conditions of generating units. Real-time information monitoring and instant data collection have been realized for photovoltaic power plant operations, facilitating real-time monitoring of efficiency, power, generation, power quality, and operation conditions to record a variety of static and transient incidents as the base for operation control.
Figure 7.12 Wind Power Operation Monitoring System
Technologies for energy storage system operation: Technological breakthroughs have been made in promoting the application of intermittent access for energy storage systems. Quantitative models with energy storage technology incorporated to improve wind power access have been established, and control technologies for optimizing wide-area coordination for stored energy stations based on multivariable coordination and multirule switching have been put forward. Through the development of demonstrative projects on wind and photovoltaic power storage and transmission (Fig. 7.13), an understanding has been established of the characteristics of joint operation of wind, photovoltaic power storage and transmission, as well as the optimized deployment of energy storage systems, which has helped to promote the construction of an online monitoring platform for large energy storage stations and to enhance the coordinated operation of energy storage and intermittent power generation.
Figure 7.13 Control Center for Joint Operation of State Wind and Photovoltaic Power Storage and Transmission Demonstration Project in Zhangbei, Hebei
1.1.4. Experimental Systems
In the course of technology R&D and engineering practice on robust smart grids, China has built complete UHV and smart grid research experimental systems, covering a UHV AC experimental base, a UHV DC experimental base, a high altitude experimental base, a UHV tower experimental base, a complete-set design and R&D (experimental) center for UHV DC transmission, a State Grid simulation center, an R&D (experimental) center for large-grid integration systems for wind power, and an R&D (experimental) center for solar energy generation, to provide world-class grid-related experimental research capabilities. These advanced experimental conditions and methods have laid a preresearch platform for key technology R&D and project construction related to the future global energy network.
UHV AC experimental base (Fig. 7.14): Located in Wuhan, Hubei, the base is equipped with a 1 km single and double-circuit UHV experimental line, complete with test facilities including an electromagnetic environment testing laboratory, a UHV AC corona cage, an environment and climate laboratory, a 7500 kV outdoor impact testing ground, a long-term live testing ground for UHV equipment. It provides a favorable platform for impact research on UHV electromagnetic environments, research on the characteristics of external insulation under high altitude, heavy pollution, serious icing, and other special natural conditions, long-term full-voltage live tests on electrical equipment, and research on operation and maintenance of power transmission and transformation equipment.
Figure 7.14 UHV AC Experimental Base in Wuhan, Hubei
UHV DC experimental base (Fig. 7.15): Located in Changping District, Beijing, with an outdoor experiment field, an experiment hall, a pollution and environment laboratory, an insulator laboratory, an arrester laboratory, UHV DC experimental lines, a corona cage, an electromagnetic environment simulation, and testing field, as well as all-round experimental and research capabilities covering UHV DC electromagnetic environments, external insulation, system operational safety, equipment and testing technologies, and operational characteristics.
Figure 7.15 UHV DC Experimental Base in Beijing
UHV tower experimental base (Fig. 7.16): Located in Bazhou, Hebei, the base meets the need for 1000 kV UHV double-circuit iron tower experiments, dimension and design load experiments on 1000 kV double-circuit, ±800 single-circuit and ±800 kV double-circuit towers, components experiments as part of the research on new tower structures, as well as overall experimental requirements.
Figure 7.16 UHV Tower Experimental Base in Bazhou, Hebei
High altitude experimental base in Tibet (Fig. 7.17): Located at Lhasa, the Tibet Autonomous Region, the base boasts an outdoor testing ground, a pollution laboratory, and experimental lines. It is the world’s highest electricity experimental base, offering favorable conditions for research on transmission and transformation lines at an altitude of 4000 m and higher, equipment insulation and electromagnetic environment characteristics. It also supports technological innovation in functional design, equipment development, control and test technologies, and engineering application.
Figure 7.17 High Altitude Experimental Base in Tibet
State Grid simulation center (Fig. 7.18): Located in Haidian District, Beijing, the center is equipped with basic test and research facilities, covering electric power system digital simulation, dynamic simulation, digital-analog hybrid simulation, and operation and security monitoring, with the focus on planning, design, construction and operation technologies for large UHV AC/DC hybrid grids. It forms a well-structured, fully functional and technologically advanced electricity system simulation and research system to achieve complete, multilevel, and multiangle simulation of power systems.
Figure 7.18 State Grid Simulation Center in Beijing
Complete design and R&D (experimental) center of UHV DC transmission (Fig. 7.19): Located in Changping District, Beijing, the center is well equipped to concurrently conduct joint test and experimental research on one UHV DC transmission project and the secondary systems of three conventional DC transmission projects. It can provide technical support, resource sharing and management platforms for key technology research, system design, valve hall design, complete-set equipment design, equipment procurement standards, equipment production supervision, system commissioning, and onsite commissioning for EHV/UHV DC transmission projects.
Figure 7.19 Complete-Set Design, Research and Development (Experimental) Center for UHV DC Transmission in Beijing
Large-scale wind power grid integration system R&D (experimental) center (Fig. 7.20): Located in Zhangjiakou, Hebei, the center has fundamental research capability in wind power generation, test capability in mobile wind turbines, experimental capability in wind power, and full test capabilities on all characteristics of wind power generating units. With the most internationally advanced test methods for wind turbine electrical equipment, the center offers model certification and grid connection testing for newly produced wind turbine products.
Figure 7.20 Large Wind Power Grid Integration System R&D (Experimental) Center in Zhangjiakou, Hebei
Solar power generation R&D (experimental) center (Fig. 7.21): Located in Nanjing, Jiangsu, the center is equipped with fundamental research capability in solar power generation, experimental and test capability in grid-connected photovoltaic system operation, and mobile test capability in grid-connected photovoltaic power stations. It can conduct performance tests on solar power generation components as well as tests on grid adaptability and resilience against interference. The center can meet the requirements for conducting research and tests on key technology for grid access, key system and equipment technology, as well as planning and design technology.
Figure 7.21 Solar Power Generation R&D (Experimental) Center in Nanjing, Jiangsu
1.1.5. Research on Global Energy Network
Preliminary research on the development of a globally interconnected energy network has been carried out in China, covering Asia/Europe power transmission, wind power development in the Arctic region, and outlook on the global energy network and related key technology and equipment, to lay a solid foundation for the development of global energy interconnections.
Research on Asia/Europe power transmission: Work in this area covers in-depth analysis of the European Union’s market demand for power, research on the energy resources and power export potential of Asian regions at the sending end, and analysis of the technology economics of transcontinental transmission between Asia and Europe. Studies have identified some market potential for Europe against a scenario of nuclear energy abandonment and fossil fuel generation decommissioning. With abundant energy resources, Asian regions at the sending end are more capable of ensuring a sustainable supply of electricity. Being economically competitive, power transmission between Asia and Europe may provide a feasible option for Europe’s clean energy development. Taking an integrated view of incremental load in the future, fossil fuel and nuclear generation decommissioning, expanding installed capacity of hydropower, new energy development and other factors, the demand for electricity in Europe is expected to amount to 140 GW during 2011–2020, of which 14.6 GW is attributable to Germany. The on-grid tariffs of Asia–Europe transcontinental power transmission will be about RMB 0.3–0.5 per kWh lower than that of wind power from the North Sea region. With growing utilized hours on the transmission channel, on-grid tariffs will fall further and add to the competitiveness of this transcontinental transmission project.
Research on Arctic wind power development and outlook on global energy network: Work in this area includes a series of topical research, covering assessment of the Arctic region’s environmental characteristics and wind power resources, evaluation of global renewable energy resources and research on transcontinental grid interconnections centered on the Arctic region, technology research on the Arctic region’s wind power development, technology research on transmission and transformation in high cold, high humidity, and high wind regions, and research on plans to export wind power from the Arctic region, and electricity from Siberia in the Russian far east. Comprehensive studies have been carried out on the status of resources, development prospects, and interconnection strategies of the Arctic region and Siberia against the backdrop of a global energy network. Based on preliminary research findings, the Arctic is a region endowed with oil and gas, as well as wind, and other renewable resources and there is a real possibility of meeting the energy requirements of low carbon, sustainable development by developing wind power in the Arctic together with natural gas, hydro, coal, combustible ice, and other resources in Siberia and the Russian far east, followed by bundling and optimized allocation on a transnational basis through UHV grids to supply to China, Japan, South Korea, and North America.
Research on key technology and equipment for global energy network: Work includes research on the key aspects of development of the future global energy network, covering resource analysis, evaluation of development potential, strategic planning, adaptive transmission and transformation of technology and equipment, operation and control technology, and new technological applications. The focus is on construction technology for transmission and transformation projects, optimized engineering design technology, DC grid technology, key technologies related to high voltage, high current electrical and electronic components, key technology for energy storage equipment, operation and dispatch structure for global power trade, simulation modeling, protection and stable control, and information support. All this will render technological support to the development of the global energy network.
1.2. Standard Formulation
Standard setting is an important part of the push for a global network of energy interconnections. A move to standardize mature technologies and equipment into unified interfaces and specifications will not only facilitate subsequent promotion and application, but also create conditions for building international-level interconnections among grids and related equipment as part of the future global energy network. Building on a foundation of continued innovation in UHV, smart grid, and clean energy technologies, China has actively promoted standard setting to establish a sound standardization system. Since 2005, China has developed 83 national standards related to robust smart grids and 204 industry standards, while actively promoting the internationalization of UHV and smart grid technologies. As at the end of 2014, State Grid was involved in the development of 21 international standards with 611 enterprise standards announced, as shown in Table 7.1.
Table 7.1
UHV and Smart Grid Standards Developed by State Grid During the End of 2014
| Fields | Categories | Number of Standards |
| UHV | International standards (application pending) | 12 |
| National standards (codeveloped) | 46 | |
| Industry standards (codeveloped) | 61 | |
| Enterprise standards (developed) | 171 | |
| Smart grid | International standards (application pending) | 9 |
| National standards (codeveloped) | 37 | |
| Industry standards (codeveloped) | 143 | |
| Enterprise standards (developed) | 440 |
System of UHV AC transmission technology standards: Riding on the results of UHV AC technology research and engineering development, State Grid has put forward a system of UHV AC transmission technology standards, covering six major areas of planning and design, equipment and materials, project construction, test and measurement, operation and maintenance, and environmental protection and safety. Of these standards, 100 enterprise standards, 33 national standards, and 41-electricity industry standards have been promulgated. The system of UHV AC transmission technology standards is shown in Table 7.2.
Table 7.2
System of UHV AC Transmission Technology Standards
| Category | National Standards | Industry Standards | Enterprise Standards (Set) |
| Planning and design | 5 | 1 | 14 |
| Equipment and materials | 19 | 7 | 34 |
| Project construction | 6 | 7 | 31 |
| Test and measurement | – | 5 | 4 |
| Operation and maintenance | 3 | 18 | 15 |
| Environmental protection and safety | – | 3 | 2 |
System of UHV DC transmission technology standards: Riding on the results of UHV DC technology research and engineering development, State Grid has developed a system of complete ±800 kV UHV DC transmission technology standards, covering all major areas of UHV DC transmission, including planning and design, equipment and materials, project construction, test and measurement, operation and maintenance, and environmental protection and safety. Of these standards, 71, 13, and 20 industry standards have been promulgated. The system of UHV DC transmission technology standards is shown in Table 7.3.
Table 7.3
System of UHV DC Transmission Technology Standards
| Categories | National Standards | Industry Standards | Enterprise Standards (Set) |
| Planning and design | 2 | 1 | 5 |
| Equipment and materials | 3 | 2 | 22 |
| Project construction | 5 | 12 | 31 |
| Test and measurement | 1 | 1 | 5 |
| Operation and maintenance | 2 | 2 | 6 |
| Environmental protection and safety | – | 2 | 2 |
System of smart grid technology standards: State Grid has formulated and announced System Planning for Smart Grid Technology Standards, incorporating eight professional disciplines, 26 technology areas and 92 standards series. A smart grid technology research system has come into being, covering technology development, equipment manufacture, tests and experiments, engineering application and standard setting, which is led by grid operators and involving joint participation by research institutions, equipment manufacturers, and electricity users. So far, State Grid has announced 417 enterprise standards related to smart grids, with involvement in developing 37 national standards and 143 industry standards, which have been promulgated. State Grid’s system of smart grid technology standards is shown in Fig. 7.22.
Figure 7.22 State Grid System of Smart Grid Technology Standards
Active participation in developing international standards: China’s UHV AC voltage standard has been accepted by the IEC. As proposed by China, the IEC has set up three technical committees to deal with HVDC transmission, smart-grid user interfaces, and grid access for renewable energy. The IEC has four secretariats based in State Grid. At the International Council on Large Electric Systems (CIGRE), a number of working groups have also been formed, led by China and covering UHV substation equipment (A3.22), UHV substation system (B3.22), UHV insulation coordination (C4.306), the breaking characteristics and experimental requirements of EHV/UHV AC switchgear (A3.28), onsite test technology applied during the construction, and operation of UHV AC substations (B3.29). At the Institute of Electrical and Electronics Engineers (IEEE), China has led the development of six standards, including three related to UHV AC, one related to energy storage, and two related to international UHV standards. China has also proposed the formulation of three UHV AC technical standards, covering insulation coordination (IEEE P1862), onsite tests (IEEE P1862), and reactive voltage (IEEE P1860).
1.3. Strategic Planning
In advancing the development of UHV and smart grids, China has developed a full-fledged strategy with supporting plans. In 2009, SGCC formulated the Planning Outline of Robust Smart Grid Development, pioneering the construction of a robust smart grid system supported by a UHV backbone and coordinated development of grids at all levels, with a strong grid structure and smart technology covering all components of an electric power system. In recent years, based on continued improvements in technology R&D and engineering practices, SGCC has carried out rolling grid-planning studies, with a sound planning system already in place.
For SGCC, the development of robust smart grids can be divided into three phases.
• Phase I (2005–2010): Preliminary stage of development. Research on key technologies for robust smart grids, together with equipment R&D, was conducted. Technology and management standards were developed and pilot projects in all areas launched. Demonstrative projects on UHV AC and DC transmission were completed, leading to a new era of UHV AC/DC hybrid transmission. Grid interconnections nation-wide were basically achieved. Technological applications were piloted in all segments of a smart grid and a collection of smart substations have been built. Smart dispatch facilities have been basically completed to improve grid coordination, building up enough grid capacity to meet the development needs of renewable energy. Smart meters have essentially covered all large and medium-sized cities in China. R&D work was carried out on smart equipment, and pilot projects on two-way interactive services were launched.
• Phase II (2011–2020): Full construction stage. Plans are underway to accelerate the construction progress of UHV grids, urban, and rural power distribution networks, promote significant breakthroughs in and widespread applications of key technologies and equipment, and basically complete the construction of a state-level robust grid supported by a UHV backbone with coordinated development of power grids at all levels. By 2020, a series of UHV AC projects covering Huainan–Nanjing–Shanghai, Ximeng–Shandong, Western Inner Mongolia–southern Tianjin, and other areas, are scheduled for completion to build four vertically aligned and seven horizontally aligned UHV AC grid structures in North China, East China, and Central China, with the completion of nine UHV DC transmission projects to meet the needs of large-scale energy bases to export hydropower from the southwest and coal-fired, wind, and solar energy generation from the western and northern regions. Across the country, five synchronous power grids will be built, including the one in North China/East China/Central China, and the rest in the north-eastern, north-western, south-western, and southern regions. The power grids in the north-eastern, north-western, south-western, and southern regions shall be asynchronously interconnected with the power grid in North China/East China/Central China through UHV or EHV DC lines, to create a new, improved transmission landscape marked by delivery of electricity from west to east and from north to south, with mutual backup and support between hydroelectric and thermal generation sources and between wind and solar power generation sources. By then, SGCC’s capability to optimize resource allocations across different regions will be greatly improved to ensure the outward transmission of electricity for consumption from large-scale coal-fired, hydroelectric, nuclear, and renewable power bases. Core smart substations will achieve a penetration rate of approximately 50%, with the full promotion of intelligent scheduling and two-way interactive services in large and medium-sized cities. The electric car charging/swapping market will be completely opened up, with the development of quick charging networks along expressways. Grid power quality will reach international advanced levels.
• Phase III (2021–2025) improvement stage. Construction of robust smart grids will be fully completed, reaching international advanced level in technology and equipment terms. By 2025, resource allocation capability, safety levels, and operating efficiency at the grid level will be significantly improved. From smart meters to user information collection systems, from smart equipment to smart substations, and from fiber-to-the-home service to comprehensive service systems based on “multinetwork integration,” all types of smart equipment will be promoted and widely applied in the power system. The level of grid intelligence will be improved markedly to accommodate the development needs of centralized and distributed clean energy sources as well as smart buildings, smart communities, and smart cities. China’s power grids will be interconnected with power grids in neighboring countries in a friendly manner to set an example for the development of a global energy network.
After years of hard work, SGCC has achieved the phased targets planned for smart grid development. Looking ahead, SGCC will carry out full-scale construction of smart grids supported by a UHV backbone and strengthen transmission and grid connection with neighboring countries. SGCC will further consolidate and improve its grid structures to form stronger receiving-end grids in North China/East China/Central China, while the capacity in regions outside North China/East China/Central China for receiving electricity will continue to improve to ensure the reception and consumption of power delivered across regions through UHV DC transmission from renewable energy bases in the west and north, and hydropower bases in the southwest. The intelligence level of power grids will be further improved to form an integrated public service platform that seamlessly links up large power bases, distributed generation, charging/swapping facilities, and smart terminal equipment. Smart distribution networks with a more logical structure will be built in urban and rural areas to remarkably improve supply capacity and reliability. Smart terminal equipment shall be widely used to realize full sharing, remote, and automatic control of two-way information. Friendly connections among distributed generation, micro-grids and super-grids shall be achieved. Smart load-end dispatch shall be applied to electric vehicles and other smart terminal equipment as well as virtual power plants to effectively realize peak load operations. The construction progress of China’s grid interconnections with Russia, the Republic of Mongolia, Kazakhstan, Burma, Thailand, Vietnam, South Korea, North Korea, Japan, and surrounding countries shall be accelerated. China will also be actively involved in research on Asia–Europe interconnections as well as the development of power bases in the Arctic and equatorial regions and power transmission across different regions to lay the foundation for the development of the global energy network.
China highly values the development of UHV and smart grids, making it the strategic focus of national energy development by incorporating it into the government’s plan for national economic and social development and its plan and related special plans for energy development, which has given a strong boost to innovation in grid development. China’s national plans for UHV and smart grid development are shown in Table 7.4.
Table 7.4
China’s National Plans for UHV and Smart Grid Development
| Year | Plans |
| 2005 | Outline of national medium and long-term planning for scientific and technological development (2006–2020) |
| 2006 | Opinions of the state council on accelerating the development of equipment manufacturing industry |
| 2006 | The eleventh 5-year planning outline for national, economic, and social development of the PRC |
| 2007 | National planning for coping with climate change |
| 2011 | The eleventh 5-year planning outline for national, economic, and social development of the PRC |
| 2011 | The twelfth 5-year plan for scientific and technological development |
| 2012 | The twelfth 5-year plan for development of strategic emerging industries |
| 2012 | The twelfth 5-year special plan for smart grid development as a major industrialization project on science and technology |
| 2013 | The twelfth 5-year plan for construction of national major innovation bases |
| 2013 | The twelfth 5-year plan for energy development |
| 2013 | Action plan for atmospheric pollution control |
1.4. Project Engineering
Guided by technological innovation and development plans, a collection of major UHV and smart grid projects have been completed in China, bringing about significant economic, and social benefits.
1.4.1. UHV Grid Projects
In recent years, a collection of UHV AC and DC transmission projects have been developed in China, fully confirming the safety, economics, and environment-friendliness of UHV transmission. The successful construction and operation of these projects clearly demonstrate the feasibility of building a global energy network on UHV technology. As at the end of 2014, three UHV AC lines and six UHV DC lines were completed and commissioned in China. In June 2014, the National Energy Administration issued the Notice on Accelerating the Construction of 12 Major Transmission Channels under the Action Plan for Atmospheric Pollution Control, including four UHV AC and five UHV DC projects. SGCC is responsible for constructing eight of these projects. In November 2014, work commenced on two UHV AC projects and one UHV DC project. As at the end of 2014, SGCC’s UHV transmission lines in operation and under development measured a total length of nearly 16,000 km, with a transformer (converter) capacity of approximately 160 GVA(GW). SGCC’s UHV projects in operation and under development are shown in Fig. 7.23 and Table 7.5.
Figure 7.23 Location Map of SGCC’s UHV DC and AC Projects in Operation and under Development
Table 7.5
SGCC’s UHV Projects in Operation and Under Development
| Items | Project Names | Voltage Grades (kV) | Commissioning or Target Commissioning Date | Line Length (km) | Transformer/Converter Capacity (10,000 kVA/kW) |
| Projects in operation | South-eastern Shanxi–Nanyang–Jingmen | 1,000 | January 2009 | 640 | 600 |
| Xiangjiaba–Shanghai | ±800 | July 2010 | 1,891 | 1,280 | |
| Extension of South-eastern Shanxi–Nanyang–Jingmen | 1,000 | November 2011 | 0 | 1,200 | |
| Jinping–Southern Jiangsu | ±800 | December 2012 | 2,059 | 1,440 | |
| Huainan–Northern Zhejiang–Shanghai | 1,000 | September 2013 | 2 × 648.7 | 2,100 | |
| Southern Hami–Zhengzhou | ±800 | January 2014 | 2,191 | 1,600 | |
| Xiluodu–Western Zhejiang | ±800 | July 2014 | 1,669 | 1,600 | |
| Northern Zhejiang–Fuzhou | 1,000 | November 2014 | 2 × 603 | 1,800 | |
| Projects under development | Huainan–Nanjing-Shanghai | 1,000 | 2016 | 2 × 780 | 1,200 |
| Ximeng–Shandong | 1,000 | 2016 | 2 × 730 | 1,500 | |
| Eastern Ningxia–Zhejiang | ±800 | 2016 | 1,720 | 1,600 | |
| Total | 15,693.4 | 15,920 |
1.4.1.1. UHV AC Transmission Projects
UHV AC transmission projects lay the foundation for building main robust grids, realizing power transmission through regional interconnections, and forming a strong grid at the receiving end to provide structural support for UHV DC, high capacity, and multicircuit transmission.
South-eastern Shanxi–Nanyang-Jingmen 1000 kV UHV AC transmission experimental and demonstration project: Phase I of this 640 km project was commissioned in January 2009 as the world’s first UHV AC transmission line to go into commercial operation, as shown in Fig. 7.24. The project involves the development of three substations and two transmission lines. Two substations are located in south-eastern Shanxi (Changzhi) Station in Shanxi and Jingmen Station in Hubei, each featuring a 3 × 1000 MVA HV transformer, and the other one, a switching station, is sited in Henan–Nanyang Station. Phase II was put into operation in September 2011, with the addition of one 3 × 1000 MVA HV transformer to each of south-eastern Shanxi Station and Jingmen Station. Two 3 × 1000 MVA HV transformers have also been added to Nanyang Station, with the installation of supporting switchgear and other equipment. With a transmission capacity of 5000 MW, the project can transmit 25 TWh of electricity every year. By linking up the North China Power Grid and the Central China Power Grid, the project has become an important energy transmission channel running in north–south direction. It produces significant economic and social benefits by bringing electricity from coal-rich North China to the south in winter and delivers surplus electricity from hydropower-abundant Central China in summer to the north, while providing backup in the event of a contingency. At an international meeting on UHV transmission technology held on May 21, 2009, Secretary General Koval of CIGRE described this UHV AC experimental and demonstration project as a great technological achievement and a milestone in the history of electric power development.
Figure 7.24 South-Eastern Shanxi–Nanyang–Jingmen 1000 kV UHV AC Transmission Experimental and Demonstration Project
Huainan-Northern Zhejiang-Shanghai 1000 kV same-tower double-circuit UHV AC transmission project: Featuring a length of 2 × 648.7 km, the project was commissioned in September 2013 as the world’s first UHV AC transmission project with double circuits on the same tower to go into commercial operation. The project involves the development of four substations and three transmission lines, starting from Huainan Substation in Anhui, through Wuhu Substation in southern Anhui, and Anji Substation in northern Zhejiang, to terminate at Liantang Substation in western Shanghai (Fig. 7.25). The project has a transformer capacity of 21 GVA and a long-term transmission capacity of 10 GW. By connecting coal-fired energy bases in Huainan and Huaibei in Anhui to load centers in East China, the project contributes to the construction of a robust grid at the receiving end of the East China Power Grid to better receive high capacity DC transmission from the Xiangjiaba–Shanghai and Jinping–southern Suzhou lines, significantly improving the East China Power Grid’s capacity for receiving power imports and also grid operational safety and stability, while promoting coordinated economic and social development in the region.
Figure 7.25 Huainan–Northern Zhejiang–Shanghai 1000 kV UHV AC Transmission Project with Double Circuits on the Same Tower
Northern Zhejiang-Fuzhou 1000 kV same-tower double-circuit UHV AC transmission project: With a length of 2 × 603 km, the project was put into operation in December 2014. With newly built Central Zhejiang (Lanjiang) Substation, southern Zhejiang (Liandu) Substation, and Fuzhou (Rongcheng) Substation as well as expanded Northern Zhejiang (Anji) Substation, the project has a transformer capacity of 18 GVA, as shown in Fig. 7.26. In the initial stage of operation, the project will have a transmission capacity of 6800 MW and a higher long-term transmission capacity of more than 10.5 GW. It links up Zhejiang Province and Fujian Province, forming an integral part of East China’s main UHV grid and contributing to the region’s capacity for receiving electricity. By further enhancing the ability to optimize allocation of energy resources through a UHV grid, the project plays an important role in ensuring supply security for Zhejiang and Fujian and servicing East China’s socioeconomic growth.
Figure 7.26 Northern Zhejiang–Fuzhou 1000 kV UHV AC Transmission Project with Double Circuits on the Same Tower
1.4.1.2. UHV DC Transmission Projects
Through a UHV DC transmission project, long-distance, high capacity and point-to-point transmission of electric power from large energy bases to load centers can be achieved. SGCC has completed and commissioned four UHV DC transmission lines, effectively transmitting electric energy from coal, hydro, wind, and solar energy bases in the western, northern and south-western regions to load centers in support of eastern and central China’s socioeconomic development.
Xiangjiaba–Shanghai ±800 kV UHV DC transmission demonstration project: Stretching 1891 km, the project was put into operation in July 2010. Starting at Fulong Converter Station in Sichuan, the project runs through a total of eight provinces (municipalities), including Sichuan, Chongqing, Hunan, Hubei, Anhui, Zhejiang, Jiangsu, and Shanghai, to end at Fengxian Converter Station in Shanghai (Fig. 7.27). It has adopted the world’s first successfully developed complete set of ±800 kV UHV DC equipment, including 6-in. thyristors, 800 kV 321 MVA converter transformers, 800 kV 1750 MW converter valve units, and 800 kV 4500 A dry-type smoothing reactors. At a rated voltage of ±800 kV and rated power of 6400 MW, the project can transmit electric power of 32.5 TWh per year with a maximum continuous transmission power of 7000 MW. It plays an important supportive role in meeting East China’s energy requirements through transmission of surplus hydropower from Xiangjiaba, Xiluodu, and Sichuan.
Figure 7.27 Xiangjiaba–Shanghai ±800 kV UHV DC Transmission Demonstration Project
Jinping-southern Suzhou ±800 kV UHV DC transmission project: Stretching 2059 km, the project was put into operation in December 2012. Starting at Jinping Converter Station in Sichuan, it runs through a total of eight provinces (municipalities), including Sichuan, Yunnan, Chongqing, Hunan, Hubei, Zhejiang, Anhui, and Jiangsu, to end at Suzhou Converter Station in Jiangsu with a transmission distance exceeding 2000 km for the first time (Fig. 7.28). The converter transformers, converter valves, smoothing reactors, and DC sleeves employed in the project were then the highest voltage, flow capacity, and highest capacity of any DC equipment in the world. The transmission line has adopted six-splitting 900 mm2-large cross-section conductors for the first time, to successfully resolve design and construction problems of UHV DC lines in regions of high altitudes, heavy icing, and serious pollution. At a rated voltage of ±800 kV and rated power of 7.2 GW, the project can deliver electric power of 36 TWh per year, serving as yet another important green energy channel for power transmission from west to east. By ensuring the timely and smooth outward transmission of surplus hydropower from Guandi and Jinping Hydropower Stations, and from Sichuan in flood season, the project effectively relieves the power shortage of East China during peak demand periods in summer and eases the mounting environmental pressure in East China’s economically developed regions.
Figure 7.28 Jinping–Southern Suzhou ±800 kV UHV DC Transmission Project
Southern Hami–Zhengzhou ±800 kV UHV DC transmission project: Stretching 2191 km, the project was put into operation in January 2014. Starting at Tianshan Converter Station in Xinjiang, it runs through a total of six provinces (autonomous regions), including Xinjiang, Gansu, Ningxia, Shaanxi, Shanxi, and Henan, to end at Zhongzhou Converter Station in Henan (Fig. 7.29). It is currently the world’s longest UHV DC transmission line and the first UHV DC project to bundle and deliver electric power from large-scale thermal and wind power bases. At a rated voltage of ±800 kV, the project leverages the flow capacity of converter valves of 6-in. large cross-section thyristors, capable of transmitting 50 TWh of electricity per year with a transmission capacity of 8 GW. The southern Hami–Zhengzhou project is the first UHV channel for outward transmission of electricity from Xinjiang, contributing to the intensive development of coal-fired, wind, and solar energy generation in north-western China and realizing optimized allocation of electric energy resources across the country to become an “electric power silk road” that connects western border areas to Central China.
Figure 7.29 Southern Hami–Zhengzhou ±800 kV UHV DC Transmission Project
Xiluodu–Western Zhejiang ±800 kV UHV DC transmission project: Stretching 1669 km, the project was commissioned in July 2014. Starting at Yibin Converter Station in Sichuan, it runs through a total of five provinces, including Sichuan, Guizhou, Hunan, Jiangxi, and Zhejiang, to end at Jinhua Converter Station in Zhejiang (Fig. 7.30). The project is the world’s first single circuit DC project to achieve full-load transmission operation at 8 GW, setting a new record in ultra-large capacity DC transmission. It can transmit approximately 40 TWh of clean hydropower each year to Zhejiang from south-western China. Connecting hydropower bases in the southwest to load centers in the east, it is another clean energy channel after the Xiangjiaba–Shanghai and Jinping–South Suzhou UHV DC transmission projects. The project makes a great difference in terms of ensuring transmission and consumption of surplus hydropower from large hydropower stations in the Jinsha River Basin in wet season, transforming resource advantages into an economic competitive edge, and optimizing the energy structure.
Figure 7.30 Xiluodu–Western Zhejiang ±800 kV UHV DC Transmission Project
1.4.2. Smart Grid Projects
Marking an important direction of global grid development, the smart grid offers clear advantages in supporting the large-scale development of clean energy, meeting diverse user requirements, realizing fault self-recovery, and improving operational economics to lay a foundation for the development of a smart-based global energy interconnection. China’s smart grid development covers power generation, transmission, transformation, distribution, consumption, and scheduling. As at the end of 2014, 358 smart grid pilot projects across 38 categories were arranged by SGCC, with 305 pilot projects across 32 categories already completed. See Fig. 7.31 for the distribution of these projects. The completion and efficient operation of these demonstration projects has set an example for incorporating elements of intelligence into the development of a globally interconnected energy network.
Figure 7.31 Distribution of SGCC’s Smart Grid Pilot Projects
1.4.2.1. Power Generation
Meeting the requirement for large-scale grid integration of clean energy generation is an important objective of smart grid development. The key lies in solving the problems of grid integration and consumption caused by the random and intermittent nature of wind, photovoltaic energy and other renewables through major measures such as forecasting wind and solar-based generation power as well as coordinated operational control of diverse clean energy sources. To forecast clean energy generation power, SGCC deployed as at the end of 2014 systems for projecting wind generation power in 20 provinces (autonomous regions and municipalities) and systems for forecasting solar energy generation power in Qinghai, Xinjiang, and Ningxia. This network of forecasting systems plays a vital role in supporting the operation, control and consumption of clean energy generation. In terms of operational control, SGCC has mastered the technology for joint operation of clean energy generation and storage through building a national demonstration project on wind and solar power storage and transmission in Zhangbei (Fig. 7.32). The demonstration project has a total capacity of 670 MW. Phase I involves development of wind power capacity of 100 MW, photovoltaic energy capacity of 40 MW, and energy storage capacity of 20 MW. The comparative figures for Phase II are 400, 60, and 50 MW, respectively. Through in-depth explorations of multiconfiguration, multifunction, adjustable, and schedulable methods of joint operations governing wind and photovoltaic power generation and storage, SGCC has learned about different types of wind turbines and the running characteristics of large-scale power-adjustable photovoltaic generation equipment and chemical energy storage devices of different types and sizes, to realize the joint operation of wind and photovoltaic power generation, storage, and transmission as an innovation model for improving grid integration and consumption of new energy.
Figure 7.32 National Wind/PV/Energy Storage and Smart Grid Demonstration Project in Zhangbei, Hebei
1.4.2.2. Power Transmission
Online condition monitoring and real-time diagnosis for transmission equipment are important for intelligent transmission. The major smart equipment is shown in Fig. 7.33. As at the end of 2014, SGCC completed installation of condition monitoring master stations for transmission and transformation equipment in 26 provinces (autonomous regions and municipalities), in which it operates, realizing condition monitoring of 4263 transmission lines as well as transmission and transformation equipment in 3597 substations. Comprehensive monitoring of UHV lines, UHV substations, converter stations, and substations on important cross-regional grids has also been achieved. Through the online condition monitoring and real-time diagnosis system, real-time recognition, monitoring and early warning, analytical diagnosis, and assessment and prediction of the operation conditions of key transmission and transformation equipment has been realized. This provides online monitoring information for production management, giving a full view of the operation conditions of transmission and transformation equipment to significantly improve the level of lean management for transmission and transformation services. Through smart inspection equipment based on helicopters and UAVs, smart surveillance has been conducted to further improve the controllability of real-time observation and monitoring of equipment operations and operational safety.
Figure 7.33 Major Smart Equipment for Power Transmission
As an important channel for outward transmission of electricity from Xinjiang, the condition monitoring system of southern Hami–Zhengzhou ±800 kV UHV DC transmission line is composed of transmission-tower front-end monitoring devices and transmission line background monitoring centers. By using wireless mobile communication, data, and images are transferred, images scrutinized, and warning messages received. A total of 17 sets of online monitoring equipment have been installed, including signal measuring, breeze, vibration, video systems, and auxiliary equipment. The project provides more stable power supply and network communication by relying on multiple power sources, including solar panels and wind power, and cable splicing and 3G networks for communication. By using the transmission line condition monitoring system, operation and maintenance staff can obtain accurate real-time technical data of air pressure, humidity, thunder, and lightning, and other natural environmental conditions in the operating environment of the transmission lines, offering a brand new technology for effectively improving operation and maintenance.
1.4.2.3. Power Transformation
As the intelligent development of substations is key to improve the intelligence level of the whole electric power system, it is of paramount importance to realize digitalization, equipment integration, service integration, and design compactness. See Fig. 7.34 for the structure of a smart substation. Full digitalization refers to the complete digitalization of all the signals, equipment, and controls in a substation to form a digitalized substation model as a platform for complete smart control and efficient management. Equipment integration means putting sensors and smart components together to improve equipment performance, control equipment dimensions, and enhance reliability by applying new technologies, new materials, new processes, optimized transformers, breakers, and other key devices. Service integration refers to the combination of protection control, automation and communication systems, with an integration of online monitoring, onsite inspection, operation, and maintenance operations, to establish an integrated service system that reduces crisscrossing and duplicate efforts for better coordinated control and improved overall efficiency. Design compactness means an integrated design based on different voltage grades and the characteristics of different substation types, to optimize the main wiring connection and station layout for space economy and lower investment costs. As at the end of 2014, SGCC operated 1527 smart substations at 110 (66)–750 kV, including 1135 at 110 (66), 344 at 220, 12 at 330, 29 at 500, and 7 at 750 kV, respectively.
Figure 7.34 Structure of Smart Substation
The 750 kV Smart Substation in Yan’an is the first unmanned substation (Fig. 7.35), completely realizing condition visualization, operation sequencing, condition-based maintenance, and intelligent operation, with innovative breakthroughs made in different areas. Among the intelligent primary electrical equipment used are breaker-mounted mechanical, gas, partial discharge condition monitoring devices and smart terminals; oil chromatography, partial discharge, other sensors, and smart terminals embedded in the main transformer, and a smart ventilation system that results in 15% lower energy consumption. Electronic transducers are employed station-wide, including the Rogowski coil electronic current transducers for 750 kV equipment and the Rogowski coil and all-fiber current transducers for 330 kV equipment, which make maintenance and overhaul easier, improves the electromagnetic property of transducers, and enhances protection and monitoring equipment performance. Also employed is a unified condition monitoring platform operating on combined off-line/on-line modes, with a standard platform for data acquisition and diagnostic analysis for condition monitoring equipment to bring about a transition in monitoring parameters from “singular diagnosis” to “integrated diagnosis.” The substation also features “one-key” switching operation by combining advanced applications like sequence control, smart alarming, fault reasoning, and analytical decision-making to realize operation automation, and change the traditional mode of switching operations. Such a facility offers the benefits of unmanning by using an integrated panoramic information platform to optimize station-wide data integration, improve substation operation, and realize advanced applications such as primary equipment visualization, condition-based maintenance, and smart alarming.
Figure 7.35 Smart Substation (750 kV) in Yan’an
1.4.2.4. Power Distribution
The development of intelligent distribution is reflected in the major breakthroughs in grid self-recovery control, distribution terminal intelligentization, and access for distributed generation. Please refer to Fig. 7.36 for the differences between a smart distribution network and a tradition power distribution network. As at the end of 2014, SGCC had developed intelligent distribution networks covering the core centers of 78 cities, operating distribution automation systems for over 10,000 10 kV lines. Based on an integration of six systems for smart grid self-recovery control, unified support for smart power distribution terminals, and grid-based online risk assessment and prewarning, the distribution automation systems are further supported by more than 20 applications of smart distribution terminals, interfaces for grid integration of distributed generation, microgrid protection and other smart equipment to improve the intensity of grid power distribution, and the controllability of distribution operation in the energy production process. This has resulted in substantially reduced unplanned outage time, limited scope of fault impact, and improved supply reliability.
Figure 7.36 Differences Between Smart Distribution Network and Traditional Distribution Network
The Chengdu power distribution automation project is the largest distribution automation pilot project implemented by SGCC with the largest number of terminals. It has completely realized distribution network operation monitoring, feeder automation, distribution network model management, and distribution network application analysis, with the establishment of an integrated shared distribution communication system as well as the operation and maintenance management systems for the integratedly controlled Chengdu distribution network and the city’s urban grids. Covering all the 10 kV feeder lines in the main urban areas, the project features 1190 sets of power distribution equipment, including switching terminals, feeder line terminals, distribution transformer terminals, switchgear stations, and boundary disconnect switches, to provide operational stability and reliability with positive effects. An interactive control model is offered to help dispatchers locate and troubleshoot a fault in one minute, realize fault isolation in 30 s, restore supply through network reconfiguration, narrow the scope of outage, and significantly improve supply reliability.
1.4.2.5. Power Consumption
Smart power consumption concerns every household. China has started work on a series of engineering practice covering smart meters, power consumption information acquisition, interactive marketing, demand side management, user-side distributed power, electric vehicle charging/swapping facilities, power quality monitoring, and power fiber-to-the-home. By the end of 2014, SGCC had established a power consumption information acquisition system with 240 million smart meters, realizing remote automatic meter reading, self-service recharging, real-time power consumption monitoring, line loss monitoring, and orderly power consumption management. Power optical fibers with integrated fiber optics and power lines have been introduced into more than 470,000 households (Fig. 7.37) to provide terminal users with internet, telecom, radio, and TV signal transmission and other value-added services, while distributing electric power, shaping a new mode of grid operation, and providing more convenient, diversified, and efficient services to the public. In Beijing, Shanghai and other locations, 28 smart communities have been developed (Fig. 7.38), with a service platform covering 287,000 households. Construction of electric vehicle battery charging/swapping networks has been accelerated, with 618 charging stations and 24,000 charging piles already installed. In 2014, 133 quick charging stations and 532 quick charging piles for electric automobiles were built along the vertically aligned Beijing–Shanghai and Beijing–Hong Kong–Macau (Beijing-Xianning) Expressways, and the horizontally aligned Qingdao–Yinchuan (Qingdao–Shijiazhuang) Expressway, covering 34 cities with the capability to sustain a driving range of 2900 km. By 2020, quick charging networks will be completed for four vertically aligned expressways serving Shenyang–Hainan, Beijing–Shanghai, Beijing–Taiwan, and Beijing–Hong Kong–Macau, as well as four horizontally aligned expressways serving Qingdao–Yinchuan, Lianyungang–Khorgos, Shanghai–Chengdu, and Shanghai–Kunming, covering 135 cities with the capability to sustain a driving range of 19,000 km (Fig. 7.39).
Figure 7.37 Power Fiber-to-the-Home System
Figure 7.38 Major Functions of Smart Community
Figure 7.39 Quick Charging Networks for Four Horizontally Aligned and Four Vertically Aligned Expressways in 2020
SGCC has basically completed the construction of a smart charging/swapping network in Beijing. As at the end of 2014, a total of 72 charging stations and 4260 charging poles had been installed, with 14 charging stations designed for buses and another 16 for taxis. Together with 1688 charging poles installed in major transport hubs, science parks, colleges, universities, and parking lots in 4S stores, a 5 km-wide “green” belt of EV charging service has taken shape at the city center. A service platform for smart charging networks has been put into operation and mobile applications for customers developed, realizing navigation, appointment, and other services to provide more convenient charging services for EV users. The network has served 9,599 electric vehicles, providing 998,000 charging times with a total power output of 31.8 GWh. The total driving mileage of the serviced vehicles combined has amounted to 75.84 million km, effectively contributing to electricity substitution and CO2 emission reduction.
In Shanghai, SGCC has made successful exploratory efforts in introducing the power fiber-to-the-home service and establishing smart communities. The power fiber-to-the-home project covers 200,000 households and, on this basis, a smart community built on an open public information platform has been developed to capitalize on a rich variety of interactive features. First, these include more reliable, faster and more convenient information network services for residents, including IPTV high definition TV programs and various interactive media services like live broadcasts, on-demand HD programs, news and information, stock information, and games. Second, smart grid features based on fiber optics are available to collect information on electricity consumption and provide mid and low voltage line loss comparison. Information on household power consumption is uploaded through a smart meter to a concentrator before being directly transferred through an optical fiber to power suppliers. The success rate and accuracy of data collection is up to 100% and real-time acquisition is achieved. Third, smart electricity consumption is promoted. Through smart electricity consumption, consumers can check and analyze information on their electricity consumption without leaving home, develop plans to be energy smart, promote energy conservation and emission reduction, and realize energy savings and rational use of power. The successful commercial operation of the power fiber-to-the-home project and the smart community in Shanghai has laid the foundation for the construction of a “smart city.”
1.4.2.6. Power Dispatch
The key point of intelligent dispatch is to conduct active and intelligent grid monitoring, analysis, early warning, decision-making support, and self-recovery control, which is crucial for ensuring efficient utilization of clean energy and safe and economic operation of power grids. In recent years, State Grid Corporation of China (SGCC) has developed a new generation of smart grid scheduling technology support systems on the basis of unified grid-wide scheduling, gradually realizing panorama operational information presentation, network-based data transfer, online safety assessment, sophisticated dispatch decision-making, operational control automation, and optimized coordination between power generation and grid transmission. A panorama presentation of grid dispatch operations can gather and monitor information on grid operation, meteorology, social security, mass media, environmental protection monitoring, wind forecasting, geography and industrial videos. As at the end of 2014, large-scale application of the smart grid dispatch control system had been successfully achieved, covering all of SGCC’s main dispatch systems at the provincial level and higher, 7,011 access points, 890,000 data acquisition points, and 2,451 phasor measurement units in generating plants/substations, with smart grid scheduling technology support system for 33 provincial dispatch systems, and 5 grid dispatch systems completed and commissioned, forming the world’s largest scheduling system with the highest controllability. It has realized real-time information sharing among all power grids at over 220 kV, three-level coordinated operation control and defense in depth. “Horizontal integration and vertical connection” of dispatch operations has also been realized, enhancing control over large grids and giving strong support to the integrated operation of the North China, Central China, and East China Power Grids and the dispatch of grid integration of clean energy. State Grid Corporation’s dispatch control center is shown in Fig. 7.40.
Figure 7.40 State Grid Corporation Dispatch Control Center
1.4.2.7. Integrated Demonstration
In order to demonstrate and test smart grid technology in general and assess the integrated efficiency of the smart grid, SGCC has developed a number of smart grid integrated demonstration projects. As at the end of 2014, nine such projects had been set up, including the Shanghai World Expo Site, Sino-Singapore Tianjin Ecocity, Yangzhou Development Zone, Jiangxi Gongqingcheng City, Shaoxing New Area in Zhejiang Province, and Zhengzhou New Area in Henan Province, with the development of regional integrated demonstration projects in 16 other regions, including Beijing and Shandong.
As shown in Fig. 7.41, the smart grid integrated demonstration project on the Sino-Singapore Tianjin Ecocity is an iconic project on China’s smart grid development. The adoption of new technologies, such as distribution automation, equipment on-line monitoring, smart scheduling, and smart substations, has improved the power quality as well as supply reliability and safety of this project. The supply reliability and voltage eligibility rate of the ecocity will reach 99.999 and 100%, respectively, while integrated line loss will decrease 1.18%, resulting in higher supply reliability. The ecocity has achieved the integration of wind and solar photovoltaic energy generation and storage at 36 kW with a microgrid, with the construction of a microgrid energy management system based on a smart dispatch support platform to fully leverage the distributed generation sources. An integrated data management platform for smart services is also established to carry out flexible and diverse exchanges with customers through the internet, SMS, phone, mail, fax, and other means of communications and to facilitate interactions in terms of onsite or remote management. Depending on their needs, customers can make inquiries about power supply and consumption, tariffs, energy efficiency analysis, and other information, while enjoying remote control and management of different types of smart home equipment. The Ecocity smart grid demonstration project will reduce oil consumption by 1,074 tons and save the equivalent of 5,930 tons of standard coal per year, with annual carbon dioxide emissions to go down 18,488 tons, producing significant results in energy conservation and emission reduction.
Figure 7.41 Smart Grid Integrated Demonstration Project of Sino-Singapore Tianjin Ecocity
1.4.3. Development of Clean Energy
In recent years, China’s clean energy development has shown phenomenal growth, building up an installed capacity of clean energy of 444 GW by the end of 2014, with a generation capacity of 1370 TWh. By installed capacity and generation capacity, hydropower accounts for 302 GW and 1066.1 TWh, respectively, compared with wind energy (95.81 GW and 156.3 TWh, respectively) and solar power (26.52 GW and 23.1 TWh, respectively). China’s wind power grids rank first in the world in grid capacity and growth.
1.4.3.1. Hydropower Projects
As at the end of 2014, there were 54 hydropower stations with an installed capacity of more than 1 GW in China. The Three Gorges, Xiluodu, and Xiangjiaba Hydropower Station rank among the top three in installed capacity in China. See Table 7.6 for an overview of China’s large hydropower stations.
Table 7.6
Overview of Large Hydropower Stations in China
| S/N | Hydropower Station | Production Capacity (MW) | Total Capacity (MW) | Unit Capacity (unit × MW) |
| 1 | Three Gorges Hydropower Station | 22,500 | 22,500 | 2 × 50 + 32 × 700 |
| 2 | Xiluodu Hydropower Station | 13,860 | 13,860 | 18 × 770 |
| 3 | Xiangjiaba Hydropower Station | 6,400 | 6,400 | 8 × 800 |
| 4 | Nuozhadu Hydropower Station | 5,850 | 5,850 | 9 × 650 |
| 5 | Longtan Hydropower Station | 4,900 | 6,300 | 9 × 700 |
| 6 | Pubugou Hydropower Station | 3,600 | 3,600 | 6 × 600 |
| 7 | Xiaowan Hydropower Station | 4,200 | 4,200 | 6 × 700 |
| 8 | Jinping Grade II Hydropower Station | 4,800 | 4,800 | 8 × 600 |
| 9 | Jinping Grade I Hydropower Station | 3,600 | 3,600 | 6 × 600 |
| 10 | Laxiwa Hydropower Station | 3,500 | 4,200 | 6 × 700 |
Source: Ref. [14].
Three Gorges Hydropower Station: As shown in Fig. 7.42, it is the biggest hydropower station in the world. The first unit was connected to the grid to generate power in July 2003, and all the units were put into operation by July 2012. The Three Gorges Hydropower Station is equipped with 34 generating units with a total installed capacity of 22.5 GW. The project is composed of three sections. Power stations on the left and on the right bank feature 26 Francis water-turbine generating units with a unit capacity of 700,000 kW (14 units are on the left and 12 units on the right bank), amounting to a total installed capacity of 18.2 GW. An underground hydropower station is located in a mountain on the right bank, featuring 6 × 700,000 kW units, with a total installed capacity of 4.2 GW. The power source station is situated in a mountain on the left bank, featuring 2 × 50,000 kW units with a total installed capacity of 100,000 kW. The average annual generation of the Three Gorges Hydropower Station is 88.2 TWh, equivalent to approximately 50 million tons of standard coal. The project transmits hydropower to Central China, East China, South China, and Chongqing (Sichuan), benefiting more than half the mainland population.
Figure 7.42 Three Gorges Hydropower Station
Xiluodu Hydropower Station: Commissioned since June 2014 with a total installed capacity of 13.86 GW, the project is the second largest hydropower station in China. On either bank of the river is located an underground station, featuring nine 770,000 kW water–turbine generating units. Annual average generation is expected to reach 57.1 TWh. A backbone project under China’s program to carry electricity from west to east, the Xiluodu Hydropower Station mainly supplies power to East China and Central China while also catering to electricity requirements in Sichuan and Yunnan. Located in the Jinsha River, it is a backbone project closest to the “west–east power transmission” route.
Xiangjiaba Hydropower Station: The project has been put into operation since July 2014 as the backbone power source in the middle of China’s “west-east power transmission” route. It boasts of eight 800,000 kW water turbines, with an installed capacity of 6.4 GW and annual average generation of 30.7 TWh. Power from this hydropower station is delivered to Central China and East China through UHV DC.
1.4.3.2. Wind Power Bases
China has achieved remarkable results in the development of large-scale wind power bases with plans for nine large wind power bases (Fig. 7.43). With a planned capacity of 11 GW, the wind power base in Hebei is already in operation with a grid-connected capacity of 9.131 GW. The wind power base in Eastern Inner Mongolia, with a planned capacity of 8 GW, was commissioned with a grid-connected capacity of 7.825 GW. With a planned capacity of 13 GW, the wind power base in western Inner Mongolia has started producing electricity with a grid-connected capacity of 12.381 GW. The comparative figures of planned capacity/grid-connected capacity for other wind power bases in operation are: Jilin Wind Power Base (6 GW/4.08 GW), Gansu Wind Power Base (11 GW/10.076 GW) (Fig. 7.44), Xinjiang Wind Power Base (10 GW/8.039 GW), Jiangsu Wind Power Base (6 GW/3.023 GW), Shandong Wind Power Base (8 GW/6.224 GW), and Heilongjiang Wind Power Base (6 GW/4.537 GW).
Figure 7.43 Distribution of Nine Large-Scale Wind Power Bases in China
Figure 7.44 Wind Power Base in Jiuquan, Gansu Province
1.4.3.3. Photovoltaic Power Generation
China’s installed capacity of photovoltaic power generation had increased from less than 300,000 kW in 2009 to 26.52 GW at the end of 2014. With the continued development of photovoltaic generation technology, the efficiency of equipment utilization continues to improve, with a steady decline in system costs. Investment in photovoltaic power systems had decreased from RMB 25,000 per kWh in 2010 to RMB 9,000 per kWh in 2013. Qinghai is the largest solar photovoltaic power generation base in China. As at the end of 2014, 153 grid-connected photovoltaic power plants in Qinghai were in operation (Fig. 7.45), with a total installed capacity of 4.23 GW.
Figure 7.45 Photovoltaic Power Base in Golmud, Qinghai Province
1.4.3.4. Distributed Power Supply
Development of distributed clean energy has also grown relatively rapidly, supported, and promoted by the government and power companies. On the whole, China’s distributed clean energy is at its early stage of development, currently with limited capacity, although its long-term growth potential is enormous. As at the end of 2013, in the regions, in which SGCC operates, there were 1677 distributed generation projects (Fig. 7.46) at the predevelopment stage, under development or with access to grids at 10 kV and less. Of these projects with a total installed capacity of 4.313 GW, 688 were commissioned with a total installed capacity of 1.504 GW. The installed capacity of distributed photovoltaic power generation connected to the grid amounts to 3.1 GW, or 16% of the installed capacity of all photovoltaic power generation.
Figure 7.46 Distributed Photovoltaic Power Base in Haining, Zhejiang Province
1.4.4. Nationwide Network Connection and Transnational Power Transmission
The global energy network is built on a network of robust grids around the world. Given China’s vast territory and reverse distribution of resources and demands, optimized allocation of energy resources over large areas is required, making the enhancement of nationwide grid connection and transnational transmission an inevitable trend. The practice gained from China’s development of nationwide network interconnection, and transnational transmission will set an important example for the development of a global energy network.
Network connection on a nationwide basis in China dates back more than half a century. Before 1949, China’s electric power industry developed slowly and power supplies were only available in a few large to medium-sized cities, with small power grids at various voltage grades. China unified its voltage grades after 1949 and a voltage grade sequence fell into place. The 110 kV transmission grid covering Beijing–Tianjin–Tangshan took shape after 1952. The 220 kV backbone of north-eastern China’s power networks quickly came into being after 1954. The 330 kV backbone supporting China’s north-western power network was gradually developed after 1972. After 1981, the construction of a series of 500 kV transmission lines gave shape to the Central China Power Grid’s 500 kV backbone framework as it stands today. Successively, 500 kV backbone frameworks were also developed for the power grids in North China, East China, north-eastern China, and South China. The completion of the ±500 kV DC line between Gezhouba and Shanghai in 1989 paved the way for DC grid interconnections between Central China and East China. With the construction of a number of 750 kV transmission and transformation projects, a 750 kV backbone framework for northwest China gradually took shape starting from 2005. In 2009, the commissioning of an experimental and demonstration project on UHV AC transmission made a cross-regional grid interconnection between North China and Central China possible. In 2010, Xinjiang was connected to the main power network in northwest China through 750 kV lines. At the end of 2011, a±400 kV DC interconnection between Qinghai and Tibet was completed and commissioned, marking the end of Tibet’s reliance on a single power network.
Six synchronous power grids have so far been developed in China, covering North–Central China, East China, north-eastern China, north-western China, South China, and Tibet to realize nationwide interconnections, with the exception of Taiwan Province. North China and Central China are interconnected synchronously through 1000 kV UHV AC, while asynchronous DC interconnections have been achieved between north-eastern China and North China, between north-western China and Central China, between north-western China and North China, between Central China and East China, and between Central China and South China. As at the end of 2013, China’s installed generation capacity amounted to 1.25 TW, serving a population of more than 1.3 billion.
By building on UHV grids, China will accelerate the exploitation and outward transmission of hydropower in Sichuan Province and Tibet. It will also expedite the construction of a power grid in the southwest, to be connected back-to-back with Central China by DC. The country’s grid interconnections may hopefully give rise to three locations at the sending end, in south-western China, north-western China and north-eastern China, and one region (North/Central/East China) at the receiving end, together with five synchronous grids under China Southern Power Grid. The result will be a more logically structured system of grid interconnections, with more well-defined functions, stronger allocation capability and higher safety levels. Capabilities will also be enhanced in terms of transmission of power from west to east and from north to south, as well as mutual support and backup between the hydropower and thermal generation sectors and between the wind and photovoltaic power generation sectors. The future of China’s grid interconnections is shown in Fig. 7.47.
Figure 7.47 The Future of China’s Grid Interconnections
To build transnational connections, China has actively pursued transmission projects at the transnational level. Currently, electric power is transmitted from Russia to China through three AC lines (two 220 and one 110 kV lines) and one DC line (500 kV), from China to Mongolia through four AC lines (one 35 kV line and three 10 kV lines), from Kyrgyzstan to China through two 12 kV AC lines. China’s power grids also transmit power to Vietnam through three 220 and four 110 kV lines, to northern Laos through one 115 kV line, and to Myanmar through one 35 and one 10 kV line. As at October 2014, China imported 16.5 TWh of electricity from Russia and 900,000 kWh of electricity from Kyrgyzstan, while exporting 600 GWh of electricity to Mongolia. The existing grid interconnections between State Grid Corporation and China’s neighboring countries are shown in Table 7.7.
Table 7.7
Existing Interconnections between State Grid and China’s Neighboring Countries
| S/N | Countries | Routes | Offshore Interconnect Ion Points | Onshore Interconnection Points | Transmission Modes | Voltage Grades (kV) | Line Lengths (km) | Commissioning Dates |
| 1 | Russia | Amur substation – Heihe Converter Station | Blagoveshchensk | Heihe Converter Station | DC | 500 | 160 | April 2010 |
| 2 | Blagoveshchensk – Aihui Circuit A and Circuit B | Aihui Station | AC | 220 | 2 × 10.9 | December 2006 | ||
| 3 | ||||||||
| 4 | Blagoveshchensk – Heihe Circuit | Heihe City | AC | 110 | 8.24 | July 1992 | ||
| 5 | Mongolia | Small port power transmission lines | Habbie Riga Port | Xin Barag Right Banner, Hulun Buir | AC | 10 | 8.2 | December 2001 |
| 6 | Small port power transmission lines | Baiyin Hushuo Port | Xin Barag Left Banner, Hulun Buir | AC | 10 | 82 | January 2008 | |
| 7 | Small port power transmission lines | Songbeier Port | Arxan City, Hinggan League | AC | 10 | 1.7 | May 2008 | |
| 8 | Yarant – Mongolia Circuit | Khovd Province | Qinghe County, Altay | AC | 35 | 64 | December 2009 | |
| 9 | Kyrghyzstan | Small port power transmission lines | Tulu Geerte Port | Torugart Port | AC | 12 | 5 (domestic) | 1997 |
| 10 | Small port power transmission lines | Sary–Tash of Osh Province | Irkeshtam Port, Wuqia County | AC | 12 | 12 (domestic) | 2001 |
Looking ahead, China will continue to strengthen power interconnections with neighboring countries: Interconnections with Russia will be achieved through UHV DC to deliver electricity from large power bases in the Russian far east and Siberia to China, with the focus on promoting the supply of power from the coal base in Yerkovtsy in the Russian Far East to Hebei Province through ±800 kV HV transmission and from the Kuzbass coal base in western Siberia to Henan Province through ± 1100 kV UHV transmission. For interconnections with Mongolia, China will look at the possibility of working with Mongolia to build coal-mine pit-head power plants in Mongolia to export electricity to China, with the focus on promoting the supply of electricity from Sibo Obo in Mongolia to Tianjin through ±660 kV DC transmission, and from Busi Obo to Shandong through ±800 kV UHV transmission. For interconnections with Kazakhstan, the focus is on promoting the supply of electricity from Ekibastuz through ±1100 kV UHV power transmission to Nanyang City, Henan Province. Through interconnections with Pakistan, China will transmit power to mitigate power shortages in Pakistan, with the focus on power delivery through ±660 kV DC transmission from Ili to Islamabad.
Based on the successful execution of its UHV and interconnection projects, China will strengthen exchanges and cooperation with all countries and alliances for promoting grid interconnections. Technical know-how and experience will be shared, with cooperative opportunities pursued in fundamental research, technological breakthrough, equipment research and manufacture, and project construction in respect of energy projects at the transnational and transcontinental levels. China will also be involved in research on energy development in key regions of the Arctic and the Equator and on major intercontinental transmission channels between Asia and Europe, in a bid to promote optimized allocation of global resources in concert with other countries around the world.
2. International Practice
Driven by a new energy revolution, major countries around the world are actively developing the smart grid and clean energy, while promoting grid interconnections. Some countries have also started research and development work on UHV technology. These practices constitute an important foundation for building a globally interconnected energy network.
2.1. Ultra High Voltage
Since the 1960s, the world’s major nations in electric power have conducted a series of R&D projects on key UHV transmission technology and equipment manufacture. The former Soviet Union, Japan, the United States, and Italy proposed the development of UHV transmission technology, with work on UHV transmission planning, design, test, and equipment development achieving good results. However, UHV transmission projects in countries like the former Soviet Union and Japan were later suspended, deferred or operated at a lower voltage in response to lower demand for high capacity and/or long-distance transmission due to sluggish load growth. Out of consideration for building technological capability, the United States and Italy have conducted relevant research whereas India and Brazil have carried out engineering work on project construction based on the requirement for developing and transmitting renewable energy.
The former Soviet Union: As one of the world’s first countries to pioneer research on UHV transmission technology, the former Soviet Union had set up several research institutes, such as a technology bureau under the Ministry of Power and Electrification, since 1960 to conduct fundamental research on UHV transmission. The country started building a 1.17 km three-phase UHV test line at the Brix Paster Substation in 1973, and started work on a 270km industrial test line between Yitate and Novokuznetsk in 1978. It owned a UHV test base featuring 3 × 1200 kV, 10–12 A cascaded test transformers and a 1000 kV impulse generator. In 1981, work started on a five-section UHV line with a total length of 2344 km. The 1150 kV Ekibastuz–Kirk Chitav line was completed and commissioned in August 1985. It has since been operating at a lower voltage because of the collapse of the Soviet Union and lower demand. Moreover, the country initiated work on a ±750 kV, 6 GW DC transmission project from Ekibastuz to Tambov, but the project was suspended and left uncompleted.
The United States: The country started work on UHV transmission technology in the latter half of the 1960s, demonstrating the feasibility of this technology through a series of research projects and tests. In 1974, American Electric Power Company and the General Electric Company carried out actual measurements of audible noise, radio interference, corona losses, and other environmental effects in the UHV transmission technology research and test station in Pittsfield. In 1974, the American Electric Power Research Institute built a three-phase 1000–1500 kV test line, and gathered experience with the electromagnetic environment, iron tower installation and transformer design through trial operations. In 1976, the United States Bonneville Power Administration started research on UHV line mechanical structure, corona, ecological environment, operation and lightning strike insulation on the Lyons testing ground and the Molo test line. To meet the needs of economic and energy development, the United States has paid more attention to the upgrading of power grid infrastructures, putting forward a vision for nationwide interconnections in Grid 2030.
Japan: Japan started R&D work on UHV transmission technology in 1972, involving Central Research Institute of Electric Power Industry, Tokyo Electric Power Company, and NGK Insulators. Under the leadership of CRIEPI, UHV test and research bases in Akagi and Shiobara were built, with field studies of electric corona noise, radio interference, wind noise, electric corona noise, and the impact on the ecological environment conducted at the Akagi base. In addition, an experimental study of air clearance of poles and towers as well as insulator strings was carried out at the Shiobara test field. In 1998, Japan started building a 426 km 1000 kV UHV transmission line designed to supply power to Tokyo. The line has been operating at a step-down voltage.
Italy: After establishing a research program on 1000 kV transmission, ENEL had been conducting UHV technology research and technological development at its test stations and laboratories since 1971. Among the 1000 kV test facilities at the Sava Reto test field are electric corona and electromagnetic environment testing devices comprised of a 1 km-long test line and a 40 m-long test cage. Experimental studies covering operation and lightning over-voltage tests and insulation characteristics had been carried out. In 1984, Italy started building a 3 km UHV overhead test line at the Sava Reto test field. The project was completed in October 1995. Some operation experience was acquired through a trial run of the project at full voltage for 2 years.
India: India embarked on a study of 1200 kV UHV AC technology in 2007. Work started in September 2011 on an outdoor test station and test line on 1200 kV UHV AC technology, with plans for building a six-circuit UHV AC line and achieving synchronous interconnections nationwide in 2020 based on 1200 kV UHV AC transmission. India also incorporated plans for developing two ±800 kV UHV DC transmission projects into its “Twelfth 5-year Plan for Grid Development” to deliver hydropower from the northeast to the west and thermal power from the eastern and central regions to the north. The two transmission lines measure 1728 km and 3700 km long. Work on one of the projects, the Biswanath Chariali–Agra ±800 kV UHV DC transmission line, commenced in March 2011, as shown in Fig. 7.48. Expected to be completed in 2016, this project has a rated power of 6 GW and a length of 1728 km. Having initiated research on 1200 kV UHV DC transmission, India started to operate the Bina test station in December 2012 and built a 2 km test line. The further development and outward transmission of thermal power from the eastern and central regions as well as hydroelectric power from the north will call for more UHV projects to be undertaken.
Figure 7.48 Map of ±800 kV UHV DC Transmission Project in India (Under Construction)
Brazil: The development of UHV technology in Brazil is driven mainly by the need to develop hydropower resources concentrated along the northern Amazon River and its tributaries. As the country’s load centers are located in the south-eastern area 1000–2500 km away from its hydroelectric bases, UHV technology is best able to support the high capacity transmission of electricity over this long distance. In February 2014, a joint venture between SGCC and ELETROBRAS won the bid for the Belo Monte ±800 kV UHV DC transmission project in Brazil, as shown in Fig. 7.49. As the first ±800 kV UHV DC transmission line of the Americas, the 2092 km project runs from the Xingu River to Estreito. Upon completion, the project will deliver hydropower resources from the west directly to load centers in the south-east.
Figure 7.49 Map of the Belo Monte ±800 kV UHV DC Transmission Project, Brazil
2.2. Smart Grid
Since the twenty-first century, major countries around the world have held smart grid development in high regard, in the hope of overcoming the challenges of energy supply, environmental protection, and climate change through this new technology and ensuring a safe, reliable, efficient, and quality power supply to meet interactive and diverse power demands. The development of smart grids all over the world covers four key areas: grid infrastructure, advanced metering, electric vehicle infrastructure, and energy storage technology.
Grid infrastructure: The main objective is to upgrade grid infrastructure and improve grid operational safety and reliability, by adopting advanced monitoring and control technologies. All countries around the world are very conscious about the role of smart grids in further ensuring the safe and stable operation of their power networks, while contributing to a reliable and quality power supply, and improved efficiency of utilizing grid resources. In its outlook on grid development, the United States has seen the low efficiency of domestic power grids, transmission congestion, and a lack of supply reliability and power quality as having a serious impact on energy reform and innovation. As a result, the United States has been actively promoting the modernization of power grids in the past decade by promulgating a flurry of policy documents, including the Energy Independence and Security Act, the Recovery and Reinvestment Act, and Strategic Plan – 2010, providing funds to enhance grid infrastructure, build an early warning system on grid stability, provide real-time monitoring of system disturbance, and prevent major power outages. Europe also faces the problem of an ageing power infrastructure. The European Union looks to make grid infrastructure development the core element of its Europe 2020 Strategy, by committing € 200 billion to transform and upgrade power and natural gas transmission networks and accelerate the construction progress of transnational energy networks. Under the plan, the investment in power grids is estimated at € 142 billion, accounting for 70% of the total investment. The grid infrastructure projects given priority for development are: (1) an offshore power grid to connect the wind power-rich North Sea to northern and central Europe, covering over 90% of the European Union’s offshore wind farms; (2) strengthening network connections in southwest Europe and the region’s interconnections with Central Europe and building an undersea interconnection between North Africa and southern Europe to export renewable energy generated in North Africa; (3) connecting the power grids in Central and Eastern Europe with those in south-eastern Europe; and (4) undertaking a grid connection project in support of a uniform Baltic Sea market. Japan has imposed higher requirements on the automation, safety, and reliability levels of power grids. The Japanese Government considers it necessary to focus more on the operational stability of power grids against a background of large-scale clean energy development. In 2010, the New Roadmap to International Smart Grid Standards was released by the International Standardization Institute for New Energy under the Ministry of Economy, Trade, and Industry of Japan, stating in unequivocal terms the need to build a network of robust grids that can withstand the impact of disasters. The key technologies required to be developed include wide area monitoring and control systems for power transmission, storage batteries for power system, distribution grid management, demand side response, and advanced metering devices, which can help improve grid operational capability.
Advanced metering: The main objective is to carry out demand side management, deploy advanced metering systems, and improve the interactivity between electricity users and the power grid. The United States has conducted work on research and practice on smart power services to improve grid operational efficiency and the quality of power services. The US Department of Energy has been mandated to launch an R&D project on grid digital information technology in support of relevant technology evaluation and research on smart meters, demand response, distributed generation, energy storage, wide area measurement, information and communication networks, and electric vehicles. All state governments are also required to provide electricity consumers with information on energy consumption, such as real-time tariffs. In terms of project construction, America’s first smart grid city has been built in Boulder, Colorado, to provide every household with a smart meter. With an intuitive understanding of real-time tariffs through the meter, customers can shift power consumption to time periods when tariffs are lower. As the largest demonstration project of its kind in the United States, the Pacific Northwest Smart Grid Demonstration Project involves 11 power utilities and 5 technology partners from the states of Idaho, Montana, Oregon, Washington, and Wyoming, covering 60,000 electricity users. The project seeks to verify the feasibility of two-way interactive communication among distributed generation, power storage, and grid infrastructure while ensuring grid safety. In Europe, two-way information flows between electricity users and power utilities are achieved through public utility and data networks based basically on smart meters, intelligent power terminals, and intelligent home appliances. Italy has installed and upgraded 30 million smart meters as part of an intelligent metering network. Germany has mandated the installation of smart meters for every new housing project and existing residential properties having undergone a major renovation. France is working to legislate a mandatory requirement that smart meters be adopted for all electricity consumers. The UK Government has passed into law a white paper on smart meters and electricity bills, requiring public utilities to adopt a market-oriented approach to operating all smart metering equipment to bring about concerted efforts among smart meter manufacturers, suppliers, operators, and data acquirers to promote smart metering.
Electric vehicle infrastructure: The main objective is to accelerate the construction of electric vehicle charging/swapping infrastructure, promote the technology and industry development of electric vehicles, and realize electric energy substitution. As an important service component of smart grid, electric vehicle charging and swapping represents an emerging segment of the electric power industry. Power utilities around the world are striving to develop an electric vehicle infrastructure to promote electric cars. The United States, mindful of the importance of a sound policy system, is the first country to introduce competition into the electric vehicle market and enhance infrastructure development, including charging points and home smart rechargers, in the hope of playing a leading and enabling role in the electric car industry. In 2012, the US Department of Energy allocated a US$120 million budget for building 14,000 charging piles. In California where electric vehicles have received one of the strongest promotional boosts ever, the Air Quality Committee earmarked US$ 27 million to develop both pure and hybrid electric automobiles. Among all European nations, Germany’s electric vehicle industry has seen faster growth. As a major car manufacturer, Germany is oriented toward R&D on key technology in order to build core competencies, with the focus on promoting electric automobiles from the perspective of energy system optimization. The German Government’s investment is mainly in R&D on related core technologies with the objective of improving basic industrial capacity. Great importance is attached to the role of electric vehicles and related charging infrastructure in improving the utilization of renewable energy and the overall efficiency of power grids. And integration of electric automobile and smart grid technologies is seen as an integral part of an action plan for electric automobiles. Japan is pursuing a diversification strategy covering both pure and hybrid electric cars and oriented toward high performance battery technology. The focus is on the setting of international standards and uniting the country’s industry alliances to promote the development of the electric vehicle industry. Advanced battery technology, together with the solid foundation that Japanese car manufacturers have laid for gasoline engines and hybrid power technology, has given the Japanese electric car industry an important advantage. Car producers, battery manufacturers, and power utilities have come together to build a pillar of strength in the electric vehicle market.
Energy storage technology: The main objective is to develop energy storage technology and demonstrative application so as to build technological capabilities for large-scale development of clean energy. In terms of project numbers and installed capacity, the United States and Japan are two major countries in the demonstrative application of energy storage. The United States is one of the forerunners in stored energy development, accounting for half of the world’s energy storage demonstration projects with successful examples of commercial application. The US Government has provided full and continuous policy and financial support for development and application of energy storage technology, especially in lithium ion battery manufacture, and system integration. Japan is a world leader in energy storage technology, including sodium-sulfur batteries, flow cells and lead acid batteries. Since the Fukushima nuclear incident in 2011, Japan has been promoting home energy storage as a key area of industry support, with the release in April 2012 of a subsidy policy on home energy storage systems. The European Union has supported national R&D and demonstration projects on energy storage in 14 countries in Europe. Through greater efforts in promoting the energy storage industry, Germany has effectively supported the development of the home energy storage market with a total investment of 50 million Euros in 2013 and 2014, to directly subsidize new purchases of energy storage systems.
2.3. Clean Energy
Major countries around the world value the exploitation and application of clean energy, with targets set for clean energy development. Clean energy is growing rapidly in the world thanks to policy, industry, and funding support. As at the end of 2013, the installed generating capacity of clean energy amounted to approximately 1940 GW, or 33.8% of the world’s total installed capacity. Clean energy generation was around 4420 TWh, or 19.6% of the world’s total generation.
Playing an important role in the global energy market, hydropower is the world’s most widely developed form of clean energy. As at the end of 2013, the installed hydropower capacity globally stood at 1012 GW, generating 3190 TWh or approximately 14.2% of the global power supply. The major hydropower stations in operation worldwide continue to provide abundant clean energy. See Table 7.8 for the important large-scale hydropower stations in overseas countries.
Table 7.8
Important Large-Scale Hydropower Stations Overseas
| Countries | Hydropower Stations | Rivers | Maximum Heads (m) | Installed Capacities (MW) | Annual Generations (GWh) | Operation Year |
| Brazil and Paraguay | Itaipu Hydropower Station | Parana | 126 | 14,000 | 90,000 | 1984 |
| Venezuela | Guri Hydropower Station | Caroni | 146 | 10,300 | 51,000 | 1968 |
| US | Grand Coulee Hydropower Station | Columbia | 108 | 6,490 | 24,800 | 1941 |
| Brazil | Tucurui Hydropower Station | Tocantins | 68 | 8,120 | 32,400 | 1984 |
| Russia | Sayano-Shushenskaya Hydropower Station | Yenisei | 220 | 6,400 | 23,500 | 1978 |
| Russia | Krasnoyarsk Hydropower Station | Yenisei | 100.5 | 6,000 | 20,400 | 1968 |
| Canada | La Grande II Hydropower Station | La Grande | 142 | 5,330 | 35,800 | 1979 |
| Canada | Churchill Falls Hydropower Station | Churchill | 322 | 5,230 | 34,500 | 1971 |
Itaipu Hydropower Station: Jointly developed by Brazil and Paraguay in October 1975, the facility is the world’s second largest hydropower station over the Parana River that divides the two countries. In 1984, the first generation set was put into production. In 1992, 18 generation sets were used to produce electricity for Phase I of the project. Two sets had been added between 2006 and 2007, this number was increased to 20, totaling 700 MW and 14 GW installed capacity. The annual energy output of the station is 90 TWh, accounting for more than 15% of the power supply in Brazil and over 70% in Paraguay.
Guri Hydropower Station: The world’s fourth largest hydropower station over the Caroni River, the station was constructed in two phases from 1963 to 1968, with a total installed capacity of 10.3 GW. The No. 1 plant under Phase I boasts three 180 MW and seven 303 MW generation units, with a total installed capacity of 2.66 GW. The No. 2 plant as an addition to Phase II features 10 × 730 MW generation units, with a total installed capacity of 7.3 GW. Following a dam heightening project, the installed capacity of the No. 1 plant was increased from 2.66 GW to 3 GW. The station currently generates 51 TWh of electricity per year. Phase I started producing electricity 5 years after work commencement. While maintaining uninterrupted operation, the project underwent expansion to add capacity to meet load growth. The low cost hydropower generated produces marked economic benefits by substantially cutting down on Venezuela’s oil consumption.
Grand Coulee Hydropower Station: The world’s sixth largest hydropower station, the facility was built on the Columbia River in 1933, with a total installed capacity of 6.49 GW and room reserved for installing four 2.4 GW generating units. The first generating unit was commissioned in 1941 and work on the No. 3 plant was completed in 1978. The No. 1 and No. 2 plants were built during the preliminary stage of development, each equipped with nine 108 MW turbine generators. The No. 1 plant features three 10 MW auxiliary generating units. The No. 3 plant was built under an expansion program, with three 600 MW and three 805 MW generating units to provide a total installed capacity of 3.9 GW. After the generating units built in the early years were recoiled, output was raised to 125 MW. The three plants boast a total installed capacity of 6.49 GW with annual generation of 24.8 TWh, enabling the station to play a pivotal role in the Columbian power system.
Wind power is a more widely developed form of new energy. By the end of 2013, the installed capacity of global wind power amounted to 318 GW. The world’s top 10 countries in terms of total installed wind power capacity are shown in Fig. 7.50. Overseas, the largest wind farm is the United States-based Alta Wind Energy Center, located in Bakersfield, California with 342 wind turbine generators each of 1.02 GW. The center is being expanded and expected to provide an installed capacity of 1.55 GW. The project can reduce over 5.2 million tons of carbon dioxide emissions each year, equivalent to removing 446,000 gasoline-powered cars from the roads. The world’s largest offshore wind farm is the London Array project composed of 175 wind turbine generators, with a total installed capacity of 630,000 kW. It can cut down on 925,000 tons of carbon emissions each year and provide electricity for half a million households following the completion of Phase I.
Figure 7.50 World’s Top 10 Countries in Total Installed Wind Power Capacity in 2013
Solar power holds great promise. By the end of 2013, the installed capacity of global solar power was approximately 140 GW. The world’s top five nations in installed capacity of photovoltaic generation in 2013 are shown in Fig. 7.51. With abundant solar energy resources, Africa is expanding generation capacity. South Africa launched a project to encourage independent power producers to purchase renewable energy, with plans to build 47 power stations, including photovoltaic, wind, and small hydro projects. Among these facilities are 27 photovoltaic power stations with a total installed capacity of 1.048 GW. In September 2013, the photovoltaic power station under the project was put into operation, as Africa’s largest facility of its kind with an installed capacity of 75,000 kW. In the same year, the Solar I photothermal power station in the United Arab Emirates, the largest facility of its kind in the Middle East, was commissioned. Covering an area of 2.5 km2 in a desert on the outskirts of Zayed City, the project is the Middle East’s largest and most technologically advanced centralized solar power project, with an installed capacity of 100,000 kW. It supplies enough electricity for 20,000 households, reducing 175,000 tons of carbon emissions every year.
Figure 7.51 World’s Top Five Nations in Total Installed Capacity of Photovoltaic Energy in 2013
In addition to wind and solar power, exploratory efforts are seen in some countries in the utilization of other forms of new energy, such as tidal power. South Korea has built the Sihwa Lake Tidal Power Plant, the world’s largest plant of its kind. Construction began in 2004 and the project became operational in August 2011. The station is equipped with 10 generating units, with a total installed capacity of 254,000 kW and an annual energy output of 550,000 MWh.
Distributed generation is developing rapidly around the world. By the end of 2011, the installed capacity of global distributed generation was 81.87 GW. Europe is one of the world’s largest distributed generation markets, best represented by Germany with 83% of its photovoltaic energy projects being of a distributional nature. By the end of 2012, Germany’s installed capacity of photovoltaic generation amounted to 32.28 GW, with 18% of projects being mounted on detached residential roofs (1–10 kW), 59% being installed on the roofs of small and medium-sized apartment or commercial buildings (10–100 kW), 6% being set up on the roofs of large-sized commercial buildings (greater than 100 kW), and only 17% being ground-mounted. Countries in the Asia–Pacific region have been introducing incentive policies to support the development of distributed generation. Japan’s distributed generation comes mainly from heat and power cogeneration and photovoltaic energy generation, collectively accounting for 13% of the national installed capacity. North America is also an important market for distributed photovoltaic energy generation. In the United States, photovoltaic energy features a mixed mode of centralized and distributed development. In 2012, the nation’s incremental capacity of photovoltaic generation was estimated at 3.31 GW, with residential, industrial, and commercial users accounting for 46.2% of this capacity. The Middle East and Africa are also pushing forward the development of distributed generation markets. Recently, off-grid distributed generation has developed rapidly in some parts of Africa.
2.4. Interconnected Grids
Power grid development generates the benefit of economies of scale. At the core of a global energy interconnection is a vision for interconnecting power grids around the world, as evidenced by the growing trend of large-grid interconnection. Currently, the world is seeing a quickening pace of grid interconnection resulting in increasing interconnection capacity. The individual interconnected power grids in North America, Europe and the Russia–Baltic Sea region represent important practices for grid interconnection around the world. Grid interconnections are also taking shape in southern Africa, the Gulf, and South America. More interconnections among countries on different continents are being developed, demonstrating a prominent trend toward grid interconnection and providing a practical basis for building a global energy interconnection.
2.4.1. Status Quo of Global Grid Interconnections
North American interconnections: These interconnections are shown in Fig. 7.52. The development of the North American interconnections can be traced back to the 1930s–1950s, when large-scale hydropower development triggered the first major growth of the continent’s power grids. In the 1950s–1980s, voltage grades were raised in line with the rapidly expanding power demand, forming a system of interconnected grids in North America. Four synchronous power grids asynchronously interconnected are now in operation across the United States, Canada, and Mexico, including the eastern and western interconnections in North America, together with the Texas and Quebec power grids. Among the four synchronized power grids, the Eastern Interconnection is linked to the Western Interconnection through six DC tie lines, to the Texas power grid through two DC tie lines, to the Quebec power grid through four DC tie lines, and one variable frequency transformer. There are more than 100 transmission lines (at 500, 230, 115 kV, etc.) in seven provincial power grids between the United States and Canada, together with a multiterminal EHV DC transmission line and a number of back-to-back DC projects. The power exchange capacity between the two countries is estimated at approximately 20 GW. Between the United States and Mexico, there are 27 mostly AC transmission lines. In North America, power is exchanged among different grid systems based on unilateral or multilateral agreements, with a mechanism for joint management, coordination, and a pool dispatch system to improve system operational reliability.
Figure 7.52 Geographical Coverage of North American Interconnections
European interconnections: These interconnections are shown in Fig. 7.53. The development of Europe’s grid interconnections dates back to 1958. The Western European interconnection slowly came into shape and was synchronously interconnected with the power grids in Central Europe in 1996. In July 2009, the European Network of Transmission System Operators for Electricity (ENTSO-E) was founded, bringing together 34 European countries and 42 transmission system operators. Today, the European grid system mainly comprises of five transnationally interconnected synchronous grids in continental Europe, Northern Europe, the Baltic Sea, the United Kingdom, and Ireland, as well as two independent power systems in Iceland and Cyprus. As at the end of 2013, 340 transmission lines were in operation covering the member states of the European power grid, including 318 AC and 22 DC tie lines interconnected mainly through AC lines at 220/285, 330, 380, 400 kV, etc. With the continued progress of interconnection work in Europe, the capability of optimizing resource allocations has continued to grow, leading to higher levels of power exchange among the member states. In 2013, a total of 387.3 TWh was exchanged, representing 12% of total power consumption. ENTSO-E is looking to further expand the scope of Europe’s interconnections to include Russia, Ukraine, Belarus, and Moldova, among other countries.
Figure 7.53 Geographic Coverage of European Interconnections
Russia–Baltic interconnection: This interconnected grid is shown in Fig. 7.54. As the world’s largest synchronous grid in terms of geographical coverage, the project spans eight time zones, linking up the grids in Russia, Azerbaijan, Belarus, Georgia, Kazakhstan, Moldova, Mongolia, Ukraine, Latvia, Lithuania, Estonia, and Kyrgyzstan, among other countries. The Finnish power grid is asynchronously connected with the Russian power grid through back-to-back HVDC transmission lines with a capacity of 1.42 GW.
Figure 7.54 Geographical Coverage of Russia–Baltic Interconnection
Southern African interconnection: The project is shown in Fig. 7.55. Since its inception in 1995, the Southern African Power Pool (SAPP) has been actively promoting transnational grid interconnections. The alliance comprises of 12 members, including Botswana, Mozambique, Malawi, Angola, South Africa, Lesotho, Namibia, the Democratic Republic of Congo, Swaziland, Tanzania, Zambia, and Zimbabwe. With the exception of Malawi, Angola, and Tanzania, the other nine countries have developed grid interconnections, currently operated at 400, 275, 220, and 132 kV. The key interconnection projects planned by SAPP fall into two main streams. One involves the development of interconnections among Malawi, Angola, Tanzania, and other member countries. The other involves building a central African transmission channel, including a Zimbabwe–Zambia–Botswana–Namibia interconnection, a transmission corridor project in central Zimbabwe, and transmission works in Zambia. Among all countries in southern Africa, South Africa boasts the largest installed capacity, accounting for 82% of SAPP’s total installed capacity.
GCC interconnection grid: Shown in Fig. 7.56, the GCC interconnection project was spearheaded by the Gulf Cooperation Council Interconnection Authority, founded in 2001 by six Gulf States to interconnect the power grids of Saudi Arabia, Kuwait, Qatar, the United Arab Emirates, Bahrain, and Oman, while taking responsibility to operate and manage the transnational grids and electricity trade among these countries. The interconnection was divided into three phases. Commissioned in December 2009, Phase I involved the development of interconnections among the power grids of the six member countries through an 800 km transmission network. Phase II, completed in 2006, saw the interconnection of power grids between the United Arab Emirates and Oman. Built in 2011, Phase III involved interconnecting the power grids developed under the first two phases. The interconnection project now provides a platform for electricity trade within the Arabian Gulf and with other regions. It has supplied an additional 1.2 GW of power to each of Kuwait and Saudi Arabia, and additional 900, 750, 600, and 450 MW to the United Arab Emirates, Qatar, Bahrain, and Oman, respectively.
Figure 7.56 Sketch Map of GCC Interconnection Grid
South American interconnection grid: As shown in Fig. 7.57, the South American interconnection grid covers two main sections. The northern section includes Columbia, Ecuador, and Venezuela and the southern section, Brazil, Paraguay, Argentina, and Uruguay. The interconnection among power grids in the south is strongest. In April 2011, the Andean Electrical Interconnection System was established by the Andean Community members Peru, Columbia, Ecuador, Bolivia, and Chile, with plans to construct an Andean Power Corridor to eventually develop an interconnection grid at the regional level. In 2013, an agreement on electricity infrastructure development and promotion was signed, with plans to complete the interconnection of power grids among Peru, Ecuador, and Columbia in 2017. The interconnection will then be extended southward to reach Chile and Bolivia, as part of a grander program to integrate the electric systems of the five Andean Community nations by 2020.
Figure 7.57 Sketch Map of South American Interconnected Grid
Central American interconnection grid: As shown in Fig. 7.58, the Central American interconnection links up power grids among Panama, Costa Rica, Honduras, Salvador, Guatemala, and Nicaragua, including 15 substations and 230 kV transnational transmission lines measuring 1800 km. In 2014, the interconnected grid carried a total output of 40.6 TWh, more than 65%, of which was generated from renewable energy, and 20.9 TWh from hydropower.
Figure 7.58 Sketch Map of Central American Interconnection
2.4.2. Research Programs for Ultra-Large Grid Interconnections
Countries in Europe, Africa, Asia, and the Americas are actively conducting research and planning for transcontinental interconnections, with the objective of achieving optimized allocation of resources over larger areas. Typical examples of efforts in this direction include the European Super Grid, the DESERTEC initiative, the Asian Super Grid, and United States-proposed Grid 2030.
The European Super Grid: In 2010, a plan to develop an electricity supergrid was jointly announced by nine North Sea countries, including Germany, France, Belgium, Holland, Luxembourg, Denmark, Sweden, Ireland, and the United Kingdom. The planned supergrid will link clean energy bases in the coastal regions of the North Sea, integrating the wind, solar, hydropower and other energy resources in these countries, as shown in Fig. 7.59. This project will cover all of Europe, linking offshore wind power as well as pumped-storage power stations in the north and solar power stations in the south to load centers in Europe, including the United Kingdom, Germany, and France. In the future, an interconnected network of energy transmissions will evolve to connect to solar power stations on African deserts. Under Phase I (2010–2015) of the three-phase plan, old thermal plants and nuclear power stations will be replaced by new energy power plants, grid access provided for large-scale wind farms, and plans formulated to strengthen and expand current transmission systems. Phase II (2015–2020) envisages the construction of more large-scale offshore wind farms and fewer thermal and nuclear power plants, to realize a balance of power supply and demand across Europe, and build interconnections among offshore wind farms and across different countries. Under Phase III (2020–2050), integration of grid systems throughout Europe will continue in an effort to further establish a pan-European grid system. Load centers in continental Europe will be connected to wind farms and pumped storage hydropower stations in Northern Europe and large-scale photovoltaic power plants in southern Europe, and also to photovoltaic solar farms in Africa.
DESERTEC solar power project: In 2009, a consortium of companies and institutions in Europe and Africa agreed on a plan to construct the world’s largest solar power project in the Sahara Desert in North Africa, as shown in Fig. 7.60. The €400 billion project is planned to be completed by 2050 to provide 15% of Europe’s annual electricity requirements through transmission lines across deserts and the Mediterranean region. The DESERTEC Industrial Initiative (DII) was also set up to solicit wider participation in the solar power plan. The initiative was initially joined by German energy giant E.ON AG, RWE Group, Deutsche Bank, Munich Re, ABB, Abengoa Solar of Spain, Cevital from Algeria, the DESERTEC Foundation, HSH Nordbank, MAN Solar Millennium, M+W Spanish Zander, Schott Solar, and SIEMENS, among others. SGCC has participated in this program, despite the withdrawal of some companies and organizations for various reasons. Under the plan, solar power stations will mainly be located in Morocco, Tunisia, and Algeria. Morocco is planning to develop a solar generation capacity of 2 GW by 2020, compared with Tunisia’s plans for building 4.7 GW of solar generation capacity by 2030. Algeria also plans to export 10 GW of clean electricity by 2030.
Figure 7.60 Sketch Map of DESERTEC Solar Power Plan Source: DESERTEC Foundation, Clean Power From Deserts–The DESERTEC Concept for Energy, Water and Climate Security, 2007.
The Asian Super Grid: Originally named “Asian Super Circle,” the transnational grid project was first proposed by Russia in 1998. During 1999–2000, Russia completed a feasibility study on large-scale export of electricity from Sakhalin to Japan through a network of underground cables. Under the Asian Super Grid plan, wind and solar power will be developed in the Gobi Desert, Mongolia, hydro and thermal power in the Russian far east, wind and solar power in China, as well as solar photovoltaic and wind power in South Korea and Japan, with plans to build a 36,000 km pan-Asian grid system that connects Russia, China, Mongolia, South Korea, and Japan, as shown in Fig. 7.61. In recent years, some progress has been made on the project. In December 2012, Mongolia’s Ministry of Energy held an international conference on Renewable Energy Cooperation and Grid Integration of north-eastern Asia. In March 2013, a memorandum of understanding on a joint feasibility study of the plan was signed among Mongolia’s Ministry of Energy, Russia’s Energy Research Institute, South Korea’s Energy Economics Institute, Japan’s Renewable Energy Sources Foundation, and the Energy Charter Secretariat. The proposal of the Asian Super Grid has met with a generally enthusiastic response from the international community. It will lay an important foundation for building a globally interconnected energy network in the future.
Figure 7.61 Sketch Map of the Asian Super Grid
United States-proposed Grid 2030: The program originated from a report released in June 2003 by the US Department of Energy’s Office of Electric Transmission and Distribution. The document “Grid 2030: A National Vision for Electricity’s Second 100 Years” presents a vision of America’s future electric system (Fig. 7.62), highlighting the importance of building interconnections on a nationwide basis and with Canada and Mexico in order to realize optimized allocation of electric power over larger areas. The plan consists of three elements. The first involves building a national electricity backbone, with the development of high capacity transmission corridors that link the east and west coasts, as well as northern Canada and southern Mexico, to fully leverage the integrated efficiency of the nationwide interconnections and improve overall grid efficiency and service quality. The second element involves building regional interconnections, with which the national backbone is connected. The connection between the regional networks is strengthened using AC or DC transmission links, whereas high capacity DC interties are employed to link adjacent, asynchronous regions. The third element involves setting up local, mini, and microgrids. The nation’s local distribution systems are connected to the regional networks, and through that to the national electric backbone. Real-time monitoring and information exchange enables markets to process transactions instantaneously and on a national basis. Customers have the ability to tailor electricity supplies to suit their individual needs. With the progress of technology, electric vehicles and fuel cell-powered vehicles may have a role in the small-scale application of distributed generation facilities. After the release of Grid 2030, the US Department of Energy funded a study on The Future Grid to Enable Sustainable Energy Systems, with 2050 as the target year. The research focus is on control and protection, technologies, and market mechanisms related to renewable energy development, power education and training, simulated analysis of system operations, as well as information and physical security, to effectively cope with the challenges of large-scale renewable energy development.
Figure 7.62 Vision of Grid 2030
The research programs on grid interconnections in the aforementioned countries and regions represent valuable exploratory and application efforts, that help build an important foundation for the development of a global energy network.
Summary
1. Countries around the world, including China, have been conducting technological research, standard setting, project construction, and planning development on UHV, smart grid, clean energy, and large grids, laying a foundation for technology research, and practice on a global energy interconnection.
2. Large-grid interconnections on each continent are beginning to take shape. This growing development demonstrates the certainty of a move toward building a global energy interconnection. The maturity and engineering application of UHV technology, provides a realistic and workable solution and technologically ensures the success of long-distance, large-scale allocation of clean energy for the global energy interconnection.
3. The development and application of smart grid technology worldwide has created a platform for the development of clean energy, of an intermittent and random nature, like wind and solar power, which will markedly improve the large-scale development and utilization of clean energy globally.
4. The development of a global energy interconnection based on UHV technology and clean energy technology will help vigorously drive the “two-replacement” policy and achieve global energy sustainability.
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