China UHV line crosses the Yangtze River construction site
It is like the 'big artery' in China's energy system. It combines the energy generated by various types of energy, integrates it, crosses the mountain valley, crosses the lake and rivers, crosses the desert Gobi, and continuously delivers electricity to factories and mines. , city, country... it is China Power Grid.
In the past 40 years of reform and opening up, China Power Grid has been the basic platform for connecting power plants and users to optimize the allocation of energy resources. In accordance with the national energy strategy, it is committed to providing safer, more economical, cleaner and more reliable power for people's lives and industrial and agricultural production. Supply, effectively supporting economic and social development, and constantly creating new records in terms of scale, capability, and innovative technologies, and enhancing international influence. At the same time, China's power grid technology and transmission standards, represented by UHV technology, are making great strides toward the world. Promote interoperability and the development of the international power industry has made outstanding contributions.
From the regional grid to the national network
The power grid, also known as the power grid, is a combination of various voltage substations and transmission and distribution lines in the power system. It consists of three units: substation, transmission, and power distribution. The task of the power grid is to transport and distribute electrical energy and change the voltage.
In line with China's rapid economic and social development since the reform and opening up, China's power grid has achieved leap-forward development. As the scale of the power grid continues to grow, its network coverage has gradually expanded.
According to the 2017 National Electricity Reliability Annual Report issued by the National Energy Administration, the total length of transmission lines of 220 kV and above in the country was about 688,000 km, and the length of such lines was only 23,000 km. During the year, it has increased by about 29 times. From the point of view of the substation capacity index, it was only 25.28 million kVA in 1978, and it jumped sharply to 3.73 billion kVA in 2017, an increase of more than 146 times. Look, the grid construction has ensured the addition of 1.7 billion kilowatts of power to achieve grid connection, meeting the need for additional 6 trillion kWh of electricity.
From the scattered and isolated various regional power grids to gradually achieve integration, to achieve interconnection, and to lay the foundation for a nationwide power grid is a major achievement in the development of power industry since the reform and opening up.
Zhang Guobao, the former director of the National Energy Administration, wrote an article about his development and construction process. Zhang Guobao pointed out that due to many reasons, China's power grid has long formed an isolated and scattered, multi-management situation. By 1999, the installed grid system of 2 million kilowatts or more There are as many as 11.
In response to this situation, the relevant departments have stepped up the construction of a unified large-scale power grid for the interconnection and mutual supply of the country, and successively completed the interconnection and interconnection of the Northeast China Power Grid and the North China Power Grid, and the Central China Power Grid and the Northwest Power Grid. The network between Hainan Island and the mainland, the mainland to supply electricity to Hong Kong and Macao.
Zhang Guobao specifically mentioned the interconnected power grid between the mainland and Taiwan. He believes that it is not complicated from a technical perspective. The distance from Pingtan in Fujian to Hsinchu in Taiwan is only about 140 kilometers. It is not much longer than the submarine cable in Hainan Island. Can achieve networking.
UHV transmission technology is advancing by leaps and bounds
On June 6, 1972, Longyangxia-Tianshui-Guanzhong 330kV AC transmission line was completed and put into operation. This is the highest level of China's high-voltage transmission in the early stage of reform and opening up. Zhang Guobao said that in 1981, through the introduction of a full set of equipment and technology, China built the first 500 kV AC transmission line, namely the Pingdingshan from Henan to the Wuchang line in Hubei. Three years later, the basis for the introduction and digestion of foreign technology. On the other hand, China built the first self-designed and constructed Yuanjin Liaohai 500 kV AC transmission line, which is the route from Yuanbaoshan Power Plant to Jincheng and Liaoyang to Haicheng. In 1989, China's first ±500 kV The DC transmission line - Gezhouba to Shanghai's Gehu DC was completed and put into use. After that, the transmission grade was steadily improved. In 2005, it reached 750 kV; in 2009, the first 1000 kV UHV transmission line was completed and put into operation. China Power Grid is striding forward. High voltage era.
2010 is the bumper year for China's UHV technology and construction. On June 18th, the national 'Eleventh Five-Year Key Construction Project and DC UHV Transmission Autonomous Demonstration Project Yunnan-Guangdong ±800 kV UHV DC Transmission Project, Double Extremely put into production, this is the world's first high-altitude, long-distance, large-capacity transmission line, marking China's power technology, equipment manufacturing has reached the international advanced level. After about 20 days, Xiangjiaba - Shanghai ± 800 kV UHV The DC transmission demonstration project was put into operation. This is China's independent research and development, independent design and self-construction. The world's highest voltage level, the largest transmission capacity, the farthest transmission distance, and the most advanced DC transmission project are obtained in China's energy field. The world-class innovations represent the highest level of HVDC transmission technology in the world today. The UHV DC transmission demonstration project is the first in the world to achieve double boost of DC transmission voltage and current, double breakthrough of transmission capacity and transmission distance.
Since then, the pace of construction of UHV lines in the country has accelerated. At present, 21 UHV projects of 'Eight Cross and 13 Straight' have been built, with a length of 38,000 kilometers and a transmission capacity of over 140 million kilowatts. Currently, the length of the line is 3324 kilometers ± 1100. KRW Xinjiang's Zhundong-Anhui Weinan UHV DC transmission line is under construction. After it is completed and put into production, the line will set a number of UHV world records.
With the innovative spirit of pragmatic and enterprising, China's electric power science and technology workers have continuously achieved new breakthroughs in China's UHV technology and won one honor after another, especially the key technologies of UHV AC transmission, complete sets of equipment and engineering applications. 'UHV ±800 thousand Volt-HVDC Project 'Two major innovations, respectively won the 2012 and 2017 National Science and Technology Progress Special Awards. Power grid enterprises in the UHV, smart grid, flexible DC transmission, large grid security control, new energy grid connection and other fields Outstanding achievements, won a large number of patents and technology awards.
Grid security set a number of world records
The scale of the power grid continues to expand, and the transmission voltage continues to rise, which makes the allocation and transmission of power across regions more reasonable and more efficient, but at the same time it may increase the risk of grid operation, and the possibility of local problems causing global ambiguity increases. In this regard, international There have been many lessons on it. For example, on November 4, 2006, there were a total of 10 million blackouts directly affecting Germany, France, Italy, the West, and the Netherlands. For example, in August 2003, it happened. Spread to the northeastern United States and southeastern Canada, affecting the population of 50 million blackouts.
Over the years, in the spirit of aggressiveness, China Power Grid has insisted on seeking technological advancement in technology development and development, and is committed to building a 'strong smart grid' that ensures safe and stable operation. Specifically, it is supported by a communication information platform. Intelligent control is the means, including the power generation, transmission, substation, power distribution, power consumption and dispatching of the power system, covering all voltage levels, achieving a highly integrated integration of 'power flow, information flow, business flow', is strong Reliable, cost-effective, clean and environmentally friendly, transparent and open, friendly and interactive modern power grid. Make full use of modern sensing technology, through online temperature monitoring device, circuit breaker online monitoring device, lightning arrester online monitoring, capacitive device online monitoring, etc. The situation is monitored in real time, and then the acquired data is collected, integrated, and finally analyzed, and the data is analyzed and managed to achieve optimal management and security management of the entire power system.
Years of operation and practice have proved that China's power grid has withstood various risks and tested the overall stability of the country's power security situation. The degree of accidents and the number of accidents have been effectively controlled for a long time. Even after severe damage caused by the Wenchuan earthquake, the local power grid passed 5 days and 5 nights. The repairs also restored a considerable part of the power supply in the disaster area, providing power support for disaster relief and post-disaster recovery and reconstruction. China Power Grid has become the world's largest safe operation and the longest safe operation record.
Participate in international standards to drive 'going out'
On December 21, 2017, after 44 months of hard work, the State Grid Corporation of China participated in the construction of the first phase of the ±800 kV UHV DC transmission project in Brazil. This is the official launch of the UHV 'going out' business in China. The first project to run is a milestone in the world of China's UHV technology services.
In the past three months, the second phase of the ±800 kV UHV DC transmission project of the Brazilian beautiful mountain, which was independently participated by the State Grid and successfully won the bid, was issued a start permit. This will be the first overseas independent investment, construction and operation and maintenance of the State Grid. UHV transmission project. It is worth noting that these two projects not only drive China's domestic nearly 8 billion yuan of domestic high-end power equipment and general contracting services to export overseas, but also contribute to the world's Chinese standards for grid transmission.
Over the years, China's power grid enterprises have vigorously strengthened their standardization work and implemented a standardization strategy. Up to now, the International Organization for Standardization, submitted by the Chinese side, has about 600 standards. The International Electrotechnical Commission has established five new technical committees since 2008. All of them were initiated by Chinese enterprises. China's electric vehicle charging and replacing standard system is ranked among the world's four major standards systems by the United States, Germany, and Japan. The international standards such as UHV and new energy integration have become important for global related engineering construction. Norm. The above efforts help China's technology, equipment, management, brand 'going out', and better serve the 'Belt and Road' construction.
State Grid Corporation of power grid enterprises China out of the vanguard, the company has invested operating the Philippines, Brazil, Portugal, Australia, Italy, Greece and Hong Kong and other seven countries and regions, the backbone of the energy network, overseas project contracting contract amount totaled $ 40 billion , driven by electrical equipment exports more than 80 countries and regions. In addition, the national grid with Kazakhstan, Russia and other countries to carry out a feasibility study on interconnection HVDC projects, deepen international cooperation capacity, driven by Chinese high-end power equipment industry sustainable development.