Smart grid to provide strong power support



On May 25, the Guangdong-Hong Kong-Macao Greater Bay Area DC back-to-back power grid project was officially put into operation, which is expected to support the "west-east power transmission" of no less than 188.3 billion KWH this year; On June 30, Zhejiang Changlongshan pumped-storage Power Station, the largest pumped-storage power station in East China, was put into full operation, and this giant "charging treasure" undertook the tasks of peak load and valley filling of the grid. On July 1, the 2080km Baihetan to Jiangsu UHVDC project was put into operation...

Since the beginning of this year, China's electric power infrastructure construction has advanced in an orderly manner. The 11th meeting of the Financial and Economic Commission of the CPC Central Committee pointed out that it is necessary to strengthen the construction of network infrastructure such as transportation, energy and water conservancy, and take networking, network replenishment and strong chain as the focus of construction, and strive to improve network efficiency. As an important driving force of economic operation and a key link of energy transformation, how is the current progress of networking, supplementing and strong chain in the power field? What should we focus on next? The reporter conducted an interview.

The power supply guarantee foundation has been continuously consolidated, and infrastructure networking, network replenishment, and strong chain have become inevitable choices

In recent years, China's power infrastructure has maintained moderately advanced development, and accelerated the transformation of the power system to adapt to large-scale and high-proportion new energy sources.

The scale of installed power capacity and the "west-east power transmission" continued to expand. At present, China's installed capacity of full-caliber power generation exceeds 2.4 billion kilowatts, and the installed capacity of wind power, photovoltaic, hydropower and biomass power generation ranks first in the world for many consecutive years. China has built 33 AC-DC UHV lines, and the scale of "west-to-east power transmission" exceeds 290 million kilowatts.

The level of rural electricity security has been significantly improved. By 2020, all counties in the country will have access to large power grids, and all villages within the coverage of large power grids will have access to power. Rural power supply capacity and reliability have been continuously improved.

The innovation capacity of electric power technology has been rapidly improved. At present, China has established a complete industrial chain of clean energy equipment manufacturing such as hydropower, nuclear power, wind power and solar power. In the first half of the year, China's total export of photovoltaic products was about 25.9 billion US dollars, an increase of 113.1%.

Although the power supply guarantee foundation has been continuously strengthened, some periods and some areas still have tight supply. "14th Five-Year Plan" period, China's electricity load and electricity consumption is expected to continue to grow, need to further strengthen the power supply security capacity; At the same time, in the process of low-carbon energy transformation, it is faced with challenges such as the new power system is still in the early stage of development, and the lack of adaptability to large-scale and high proportion of new energy connections and consumption. To make up for these shortcomings, power infrastructure networking, network, strong chain has become an inevitable choice.

The person in charge of the relevant departments of the National Energy Administration introduced that for the construction of power infrastructure, networking mainly includes the development of UHV transmission channels; The supplementary network mainly includes optimizing and improving the layout of the main power grid, strengthening the transformation and upgrading of the urban distribution network and the construction of strong local power grids, developing distributed smart grids, and improving the power infrastructure in rural and remote areas. Strong chain mainly includes strengthening the security and intelligence level of power infrastructure, making the power system more flexible and intelligent, and promoting the coordination and interaction of source and network load and storage. "Accelerating the networking, replenishment and strengthening of power infrastructure is an inevitable requirement for ensuring national energy security and achieving the target of carbon peak and carbon neutrality on schedule."

Taking networking, networking and strong chain as the focus of construction will also help play the role of investment driving. In June, the State Grid announced more than 500 billion yuan of grid investment this year, reaching the highest level in history, and is expected to drive social investment of more than 1 trillion yuan.

Improve the intelligent level of the power grid to ensure reliable, stable and low-cost power supply

A "White House" stands in Taiping town, Xinxing County, Yunfu City, Guangdong province. Here is the "intelligent brain" of the 10 kV distributed grid of the Southern Power grid - energy storage switching station, which can make the distributed grid flexibly convert between shutdown, grid-connected operation and off-grid operation, and at the same time, it is like a large "charging treasure", which can store 2 megawatts of electricity. According to reports, last year, the local construction of this "source (hydropower) network load and storage" medium voltage distributed grid can realize the full absorption of small hydropower, reducing about 43% of the abandoned hydropower.

The 11th meeting of the Financial and Economic Commission of the CPC Central Committee proposed the development of distributed smart grids. How to understand the distributed smart grid? What does it do?

The person in charge of the relevant departments of the National Energy Administration introduced that the distributed smart grid is based on the grid platform, and actively ADAPTS to the development of large-scale distributed new energy by improving the intelligence level of the grid.

On the one hand, on the power side, it can support distributed power supply access to the grid, meet electricity demand nearby, and provide users with continuous reliable power supply.

Du Zhongming, president of the General Institute of Electric Power Planning and Design, introduced that the development and utilization of new energy in China presents a centralized and distributed situation. The "large clean energy base + large power grid" approach mainly solves the problem of "electricity coming from afar", but long-distance transmission faces constraints from investment costs, land, environment and other factors. To promote the large-scale and high-proportion development of new energy, it is also necessary to rely on distributed power supplies, give full play to the advantages of being close to the load and nearby consumption, and achieve "electricity from the side".

On the other hand, on the load side, it can support the access of many kinds of load subjects such as electric vehicle charging piles, new energy storage, and virtual power plants, and meet the diversified "plug and play" access needs.

"The new energy output has the characteristics of intermittency, volatility, randomness, and so on. As the proportion of new energy continues to increase, the difficulty of maintaining the balance of the power system continues to increase, and the problem of the lack of flexibility adjustment resources of the traditional power grid becomes prominent." Du Zhongming said that the fine regulation of user electricity through the distributed smart grid is equivalent to recreating a "power plant", which will become a key means to ensure the reliable, stable and low-cost supply of power in the new power system.

"It is currently the peak period of electricity prices, and it is recommended to charge at 12 o 'clock during the low period of electricity prices." At 10 am, Mr. Zhang, a teacher at the Institute for Advanced Study of the University of Science and Technology in Hangzhou, originally planned to charge an electric car, and after adopting the suggestions provided by the charging app, he saved about 70% of the electricity bill. Last year, State Grid Hangzhou Power Supply Company put into operation in the campus "optical storage and charging integration" intelligent collaborative project, including distributed photovoltaic, energy storage power station, 3 sets of fast charging pile, 20 sets of slow charging pile and a set of optical storage and charging intelligent control system.

According to the data provided by the National Energy Administration, in recent years, the structure of China's distribution network has been further optimized, the level of intelligence has been greatly improved, and the acceptance capacity of distributed power has been steadily improved, fully guaranteeing the flexible access of more than 100 million kilowatts of various distributed power sources.

The development of distributed smart grid also needs to make efforts in key technologies and business models

The surveyed experts believe that the development of distributed smart grid, to improve the "hardware" of key technologies, business model "software" and other aspects of joint efforts.

At the key technical level, Du Zhongming believes that it is urgent to study the coordinated control technology that ADAPTS to massive distributed power supplies and multiple load access, the intelligent power grid scheduling and operation technology, and the key technologies for the digitalization and intelligent promotion of distributed smart grids.

As of the end of June this year, the number of pure electric vehicles in the country reached 8,104,000, and the installed installed capacity of distributed photovoltaic power generation was 127 million kilowatts, equivalent to the installed capacity of more than five Three Gorges power stations. "The charging load of electric vehicles has a large randomness, the photovoltaic power generation during the day can meet most of the power demand, the photovoltaic power generation at night has no output, the superimposed charging load of electric vehicles, the evening peak power balance and the safe and stable operation of the system will face a great test." Du Zhongming suggested building a technical support system for the integration of power distribution and electricity consumption, and opening up the "last kilometer" of the distribution network to connect users.

At the business model level, it is necessary to improve the price mechanism and market rules of "wall sale of electricity" (that is, market-oriented trading of distributed generation). "' Selling electricity through the wall 'helps to promote the consumption of renewable energy nearby, but at present, the charging standard for' network fees' is not clear." How to balance the demands of transaction parties and grid enterprises, and improve the electricity price mechanism to support the self-use and nearby use of distributed clean energy generation needs to be further explored." Du Zhongming said.

The person in charge of the relevant department of the National Energy Administration told reporters that in the next step, the National Energy Administration will take the construction of a new power system as a guide to promote the upgrading of the form, technology and function of the traditional power grid, significantly improve the power supply security and flexible interaction ability of the distributed smart grid, and realize the more coordinated development of the source network load and storage.

First, play a leading role in planning, and strengthen the planning and top-level design of distributed smart grids. Second, in areas with good demand response resource conditions and rich new energy power generation resources, the distributed smart grid is supported to promote the consumption of distributed new energy power through demand response according to local conditions. Third, accelerate the research of distributed smart grid technology, and bring together the forces of scientific research institutes, universities and enterprises to achieve core technology research.