The hottest UHV DC transmission is the Chinese sta

2022-08-26
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UHVDC transmission leads the world in the "Chinese standard"

China has fully mastered the key technologies such as UHVDC planning and design, experimental research, equipment development, engineering construction and operation management, and has been comprehensively promoted and applied at home and abroad. The transmission capacity and transmission distance have been continuously improved, and the progressiveness, reliability, economy and environmental friendliness have been comprehensively verified, "Created by China" and "led by China" have been realized. UHV DC transmission technology is of great significance to ensure energy security and promote the coordinated development of eastern and western regions

innovative development of DC transmission from afar

DC transmission is to realize electric energy transmission in the form of high-voltage DC. At the sending end, three-phase AC is rectified into DC through the converter station, and then sent to another converter station through the DC transmission line for inversion into three-phase AC, which is sent to the receiving end for AC use. The development of DC transmission is closely related to the development of Converter Technology (especially high-voltage, high-power converter equipment). China began DC transmission research in the early 1960s. In 1987, Zhoushan DC transmission project, which was independently designed and fully met the long-term harsh quality requirements of vanadium batteries, was completed, and the Ministry adopted domestic equipment. After more than 30 years of development, China's DC transmission projects are leading the development of DC transmission technology in the world from voltage to capacity

China's energy resources and power load demand are inversely distributed. Two thirds of hydropower resources are concentrated in the southwest, more than 80% of land wind and solar energy resources are concentrated in the western and northern regions, while more than 70% of power consumption is concentrated in the eastern and central regions, and the energy base is 1000-4000 kilometers away from the load center. According to the characteristics of China's energy resources, the state has put forward the development strategy of "transmitting electricity from the west to the East"

overcome world-class problems and speed up the adjustment of energy structure

UHV DC transmission system refers to DC transmission systems with DC voltage levels of ± 800 kV and above. The technical and economic analysis shows that when the transmission power is greater than 4million kW and the transmission distance reaches 1500 km, by comparing the annual cost indicators (annual cost per kilowatt hour, annual cost per kilometer) of unit transmission distance and unit transmission power, the use of UHVDC is a reasonable choice in terms of technology and economy. By developing UHVDC transmission, we can transform the power resource advantages of western provinces into economic advantages, change the imbalance between energy and economy between the East and the west, speed up the adjustment of China's energy structure, and promote the coordinated economic development of the East and the West. It will provide export channels for power resources in the Jinsha River, Lancang River, Yalong River and other basins, making it possible to develop large-scale hydropower resources in Sichuan, Yunnan and Tibet; Provide transmission channels for clean energy such as wind power and photovoltaic in Xinjiang, Gansu and Qinghai, so as to create favorable conditions for promoting energy supply side reform and energy structure transformation

compared with the conventional HVDC transmission system, the equipment manufacturing technology of UHVDC System is difficult, especially the important converter equipment such as converter transformer, smoothing reactor, DC bushing, converter valve, etc., which need to overcome many difficulties in manufacturing technology. On January 8, "UHV ± 800 kV DC transmission project" won the special prize of the national science and technology progress award. UHV ± 800 kV DC transmission technology is the core technology of China's energy and power development. It is a major key technology to implement China's large-scale cross regional energy optimization strategy. It has the characteristics of low transmission loss and high utilization of transmission corridors. UHV ± 800 kV DC transmission technology is extremely complex, and there is no experience to learn from at home and abroad, so it is very difficult to develop it. The State Power Corporation and other units jointly worked with more than 160 units such as scientific research, universities and equipment manufacturing to tackle key problems, completed 141 key technology studies, created 37 world firsts, and solved world-class problems such as insulation characteristics under ultra-high voltage and extra large current, electromagnetic environment, equipment development, test technology and so on

seize the commanding height of technology. The UHV demonstration project

± 800 kV HVDC transmission system was first built in China and successfully put into commercial operation. In 2006, China began to implement the UHVDC demonstration project. In 2006, the Yunnan Guangdong ± 800 kV DC transmission project was started, with a bipolar transmission power of 5million kW and a transmission distance of 1373 km. On June 18, 2010, the bipolar was officially put into operation. Xiangjiaba Shanghai (upward) ± 800 kV DC transmission project has a maximum transmission capacity of 7million kW and a transmission distance of 1907 km. On July 8th, 2010, Xiangjiaba Shanghai ± 800 kV HVDC demonstration project was put into operation

Xiangjiaba Shanghai ± 800kV UHV DC transmission project starts from Fulong converter station in Yibin, Sichuan, and ends at Fengxian converter station in Shanghai. It passes through six provinces and two cities, including Sichuan, Chongqing, Hubei, Hunan, Anhui, Jiangsu, Zhejiang, Shanghai, and crosses the Yangtze River four times. It is the world's first UHV DC transmission project with a total length of more than 1900 kilometers

the project, independently developed, designed and constructed by China, is a world-class innovation in China's energy field, representing the highest level of HVDC transmission technology in the world at that time. 129 major technologies have been completed in the project construction, and the comprehensive localization rate of equipment has reached 68.52%. There are many assembly accessories, and the construction is difficult. At that time, there was no precedent in the world to learn from. The successful operation of the upward project marks the comprehensive breakthrough made by the State Power Corporation of China in ultra long distance and ultra large-scale transmission technology, and has laid a solid foundation for accelerating the large-scale development of clean energy in Western China and increasing the proportion of non fossil energy; It marks that China has the comprehensive ability to produce and systematically integrate a full set of UHVDC key equipment, significantly improving the independent innovation ability and core competitiveness of China's electrical equipment manufacturing industry

the world's most Jiquan UHV DC transmission project

Changji Guquan (Zhundong South Anhui) ± 1100 kV HVDC transmission project is the world's first DC transmission project with the highest voltage level, the largest transmission capacity, the longest transmission distance and the most advanced technology. It is the second UHV transmission project after the Hami South Zhengzhou ± 800 kV HVDC transmission project, the national implementation of the "Xinjiang power transmission" strategy, The total length is 3324 kilometers. The voltage level of the project is ± 1100 kV, and the rated transmission capacity is 12million kW. It starts from Changji converter station in Xinjiang and ends at Guquan converter station in Anhui, passing through 6 provinces (autonomous regions) in Xinjiang, Gansu, Ningxia, Shaanxi, Henan and Anhui

the development of Jiquan engineering equipment is difficult. The converter valve, converter, DC through wall bushing and horizontal reactance voltage have been raised to 1100 kV. The development is facing the test of design, production process, test ability and method. The requirements for equipment localization are high. The AC and DC main equipment is basically purchased domestically, and the equipment is independently designed, developed, produced and supplied. The level of equipment localization should be further improved. After the project is put into operation, 66 billion kwh of electricity can be transmitted to East China every year, 30.24 million tons of coal transportation can be reduced, 24000 tons of smoke and dust, 149000 tons of sulfur dioxide and 157000 tons of nitrogen oxides can be reduced, which will effectively promote the realization of the goal of air pollution prevention and control in the Yangtze River Delta region

On March 29, the Xinjiang section of Changji Guquan UHVDC transmission project was completed. On April 15, with the smooth crossing of the last phase of the conductor across the natural graben Yangtze River, the ± 1100 kV Yangtze River crossing project was completed. This is the first time that the ± 1100 kV transmission line crosses the Yangtze River. Its main crossing tower is 225.2 meters high, the single base tower weighs 1259 tons, and the total crossing length is 2900 meters, all of which are the highest in the whole line. As of May 13, the main control building, relay room and bipolar low-end valve hall of Guquan converter station have fully realized "dust-free" management, and 910000 meters of cable laying has been completed, accounting for 99%; Installation of double pole low-end valve hall converter valve and auxiliary equipment 80%; All special tests of 1000 kV GIS equipment were successfully completed, and 1162 installation units of 500 kV GIS equipment were completed

biomedical materials are the basis of its development

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as of April 2018, State Grid Corporation of China has completed 10 ± 800 kV high-voltage DC projects, including Xiangjiaba Shanghai, Hami Zhengzhou, Jinping Southern Jiangsu, Xiluodu Zhejiang, Lingzhou Shaoxing, Jiuquan Hunan, northern Shanxi Nanjing, Ximeng Taizhou, shanghaimiao Shandong, zarut Qingzhou; One ± 1100 kV Changji Guquan UHV DC project is under construction. Among them, the Xiangjiaba Shanghai, Hami Zhengzhou and Jinping Sunan ± 800 kV HVDC demonstration projects won the national gold medal for high-quality projects, and the Xiluodu Zhejiang Shuanglong ± 800 kV converter station won the 2016-2017 Luban Award for China Construction Engineering

at the same time, China's UHV is providing the world with experience and technology that can be used for reference. State Grid Corporation of China successfully won the bid for the phase I and phase II projects of ± 800 kV DC transmission from meilishan power in Brazil, realizing the output of the whole industrial chain and value chain of UHV transmission technology, standards, equipment, general contracting and operation management in China. On December 21, 2017, the phase I project of ± 800 kV High Voltage DC transmission in Mount Meridien, Brazil, jointly invested and constructed by the State Grid Corporation of Brazil and the 29 carbon structural steel Brazilian national electric company, was put into operation at the receiving end of the istredo converter station in Brazil. The first phase of the project, which has been put into operation, marks the official commercial operation of China's first UHV "going global" project

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