UHV grid refers to 1000kV AC or ±800kV DC grid. The transmission voltage is generally divided into high voltage, ultra high voltage and UHV. Internationally, high voltage (HV) usually refers to a voltage of 35 to 220 kV; ultra-high voltage (EHV) generally refers to a voltage of 330 kV or more and 1000 kV or less; UHV refers to a voltage of 1000 kV or more. High-voltage direct current (HVDC) usually refers to a voltage of ±600 kV and below, while voltages of ±800 kV and above are called UHVDC.
The UHV ±800 kV DC transmission project completed by the National Grid and China Southern Power Grid Co., Ltd. was awarded a special prize for the 2017 National Science and Technology Progress Award on January 8. This technology is currently the world's most successful transmission technology with the highest voltage, the largest capacity, and the longest economic transmission distance. In the construction of the “One Belt and One Roadâ€, the promotion of this technology has been intensified, making it a bright “China Business Card†for “going out†in China.
The bottleneck of the growth rate of UHV investment
According to the "Analysis Report on the Market Forecast and Investment Strategy Planning of UHV Equipment Industry" released by the Industry Research Institute of Qianwang, the investment space for China's power grid investment is about 500 billion yuan. The national grid investment has increased from 250 billion yuan in 2008 to nearly 500 billion yuan in 2016. The amount of investment has doubled in 8 years, with an average annual compound growth rate of 9%. In recent years, the national grid investment has remained at more than 450 billion yuan. The growth rate has been declining year by year, and the market space has remained at around 500 billion yuan.
The cumulative UHV investment amount before 2012 is about 20% CAGR, and it has entered rapid growth since 2014. The growth rate in 2015 exceeded 50%, and the growth rate peaked. In 2016, UHV cumulative investment growth rate decreased year-on-year. More than 20 percent. The UHV cumulative investment growth rate is similar to that of the high-speed rail and nuclear power industries.
2008-2017 China's Power Grid Investment Market Space and Growth Rate
±800 kV DC transmission technology has obvious advantages
China's energy resources and electricity load distribution are extremely uneven. More than 80% of energy resources are distributed in the west and north, and more than 70% of the electricity consumption is concentrated in the eastern and central regions. The contradiction between energy supply and economic development is prominent. The development of large-capacity, long-distance, and high-efficiency power transmission technologies is an inevitable choice for the large-scale configuration optimization of China's power energy across regions.
The UHV ±800 kV DC transmission project brings significant economic and social benefits. Its transmission capacity is two or three times that of the ±500 kV DC project, the economic transportation distance is increased to 2-2.5 times, the operational reliability is increased by 8 times, the unit transmission distance loss is reduced by 45%, and the floor space per unit capacity line corridor is reduced. 30%, the cost of unit capacity decreased by 28%.
UHV DC transmission technology is internationally recognized as the world's leading technology in China. At present, only China has fully mastered this technology and has begun large-scale engineering applications. In 2010, China independently established the Yunnan-Guangdong, Xiangjiaba-Shanghai UHV ±800 kV DC demonstration project. By the end of 2017, a total of 12 UHV DC transmission projects had been completed in the country. The annual transmission of electricity exceeded 450 billion kwh, of which Clean energy accounted for more than 80% of the total, equivalent to reducing annual consumption of 170 million tons of standard coal in the eastern and central regions and reducing 450 million tons of carbon dioxide emissions. It is the main transmission channel for the Air Pollution Prevention Action Plan.
Promoting UHV technology as "Chinese business card"
Our UHV transmission technology has created many records in its technical theory, mechanism, engineering construction and equipment manufacturing capabilities. From the creation of China to lead China, it occupied the commanding heights of the world's power grid technology. It is recommended that like pushing high-speed railways and “Hualong I†nuclear power projects, we should promote electric equipment to go abroad, especially the UHV DC transmission project contracting and equipment exports.
On the one hand, UHV DC transmission technology, engineering operation design technology, and China's large-scale power grid operation technology are transmitted as Chinese business cards. China has a very good technical foundation, manufacturing capacity, and design capabilities. In response to the different needs of different countries for transmission technologies, China has the ability to provide different solutions. These technical solutions can be rolled out to the sea to enhance China's "going out" products and equipment. Added value.
On the other hand, continuous investment and continuous optimization of the existing technology level, from 2016, China Southern Power Grid undertakes the national key R&D program and independently develops flexible DC transmission technology. At present, China Southern Power Grid is constructing a UHV DC transmission project from Yunnan Power Transmission to Guangdong, adopting a traditional hybrid mode of DC and flexible DC to improve the safety and reliability of the power grid. It is the first in the world.
Flexible HVDC transmission technology is the development direction of the future power grid
The technology is more demanding in terms of digitization and intelligence. It is hoped that the project can be supported by the relevant departments of the country in terms of project approval, hardware and software R&D, and talent introduction, so that this "Chinese wisdom" has more room for development.
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