Ultra-high voltage – power highway

According to the China Central Radio and Television Economic Voice "World Finance" report, the Standing Committee of the Political Bureau of the CPC Central Committee pointed out at a meeting that accelerating the construction of new infrastructure such as 5G networks and data centers has attracted great attention from all walks of life. Traditional infrastructure refers to large buildings such as railways, roads, bridges, and water conservancy projects, which are often referred to as "railway, highway, and infrastructure." "New infrastructure" refers to infrastructure construction focused on the technology end, covering 5G, artificial intelligence, industrial Internet, etc. It has a wider range and better reflects the characteristics of the digital economy, and can better promote China's economic transformation and upgrading.

What does the "new infrastructure" mainly include? What is the "new" part? What is its important role in stabilizing the economy? What changes will it bring to social development and people's lives? The second article in the series "Decoding the New Infrastructure": Ultra-high voltage - power highway.

What is UHV?

Eleven years ago, the world's first ultra-high voltage transmission project was put into commercial operation in my country, and my country entered the ultra-high voltage era. Ultra-high voltage power grid refers to an AC power grid of 1,000 kV and above or a DC power grid of ±800 kV and above. This voltage is about 5,000 times the civilian voltage. Why does the transmission grid need to raise the voltage so high? Zhang Lizi, a professor at North China Electric Power University, told reporters that this is mainly to achieve long-distance power transmission.

Zhang Lizi introduced: "The voltage level of the transmission network is high and low, and generally develops from low voltage level to high voltage level. Because the power loss of low voltage level transmission is large. Therefore, the voltage level is increased for long-distance transmission, which can reduce the power loss of long-distance transmission."

Why do we need UHV?

Data shows that the amount of electricity transmitted by a 1,000 kV UHV DC grid is 5 to 6 times that of a 500 kV DC grid, and the transmission distance is 2 to 3 times that of a 500 kV DC grid, which can be called an electric highway. As for why long-distance power transmission is necessary, Zhu Guangchao, deputy chief engineer of the State Grid Corporation of China, said that this is actually closely related to the distribution and use characteristics of my country's energy. Zhu Guangchao introduced: "China's wind power and solar power are mainly concentrated in the northwest, and hydropower is mainly concentrated in the southwest. China's electricity load is mainly in the central and eastern parts, such as Shanghai or other eastern cities, which have a large demand for energy."

Statistics show that more than 70% of my country's energy demand is concentrated in the central and eastern parts of the country, while 76% of coal is concentrated in the north and northwest, and 80% of hydropower is concentrated in the southwest. This contradiction has made ultra-high voltage gradually become a new infrastructure.

Investment in projects under construction reaches hundreds of billions

At present, my country has 22 UHV lines in operation, and another 8 lines are under construction. Han Xiaoping, chief information officer of China Energy Network, said that UHV construction requires high technology and huge investment. Han Xiaoping said: "First, we need to raise the electricity to a higher level, and the voltage increase itself requires a lot of investment, such as transformers and switches. In addition, the construction of transmission lines requires the construction of high-voltage towers, and the cables are transported from the northwest or southwest regions to the load center for long distances, and then the voltage is reduced. This requires a lot of supporting investment."

The total construction scale of the major UHV projects that State Grid is preparing to resume work on recently is as high as 71.3 billion yuan. In addition, the total investment in State Grid's newly started projects is as high as 26.5 billion yuan. Taken together, State Grid's investment in UHV projects under construction is as high as 100 billion yuan.

In addition to these investments, as a new infrastructure, UHV construction will also drive the development of a number of power transmission and distribution parts industries, such as transformers, switches, capacitors, lightning arresters, converter valves, etc. Chen Weijiang, an academician of the Chinese Academy of Sciences, said that these technologies and equipment have now become my country's new business card. Chen Weijiang said: "It is particularly proud that my country's UHV DC transmission technology has been exported to Brazil. UHV equipment is now a business card for China in the international power market."

The role will continue to improve in the future

Of course, the impact of UHV has long gone beyond the energy industry itself. It connects thousands of lights and continuously supplies nutrients to the Chinese economy. In Han Xiaoping's view, its role will continue to increase in the future. Han Xiaoping said: "Now there are more and more smart factories, especially after the COVID-19 epidemic, many places are promoting the smart manufacturing and distribution of factories. The smart manufacturing actually requires electricity to support it. Therefore, our electricity consumption will increase with the development of economy and technology and the overall upgrading of the country. UHV construction can promote this process."