Smart grid, providing strong power support

In recent years, China's power system to speed up to adapt to the large-scale high proportion of new energy direction. In the face of the challenges in the process of low-carbon energy transition, infrastructure networking, network, strong chain has become an inevitable choice. In the future, the distributed smart grid will be further developed, and efforts will be made in key technologies, business models and other aspects to promote the more coordinated development of source network load storage.

On May 25, the Guangdong-Hong Kong-Macao Greater Bay Area DC back-to-back power grid project was officially put into operation. This year, it is expected to support the "west-to-east power transmission" of no less than 188.3 billion kilowatt-hours; on June 30, the largest pumped storage power station in East China-Zhejiang Changlongshan Pumped Storage Power Station was fully put into operation. This huge "charging treasure" undertakes the tasks of peak shaving and valley filling of the grid; July 1, the 2080 kilometers......

This year, China's power infrastructure construction in an orderly manner. The 11th meeting of the Central Financial and Economic Commission pointed out that it is necessary to strengthen the construction of network-based infrastructure such as transportation, energy, and water conservancy, take networking, network replenishment, and strong chains 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, what is the progress of interconnection, network replenishment and strong chain in the current power field? What aspects should be focused on next? The reporter conducted an interview.

Power supply security foundation continues to be solid, infrastructure networking, replenishment, strong chain has become an inevitable choice.

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

The scale of power installation and "west-to-east power transmission" continues to expand. At present, my country's installed capacity of full-caliber power generation exceeds 2.4 billion kilowatts, and the installed capacity of wind power, photovoltaics, hydropower, and biomass power generation has ranked first in the world for many years; 33 AC and DC UHV lines have been built nationwide, and the scale of "West-to-East Power Transmission" exceeds 0.29 billion kilowatts. Kilowatt.

The level of rural power security has been significantly improved. In 2020, the country's counties and counties will be connected to large power grids and villages within the coverage of large power grids. Rural power supply capacity and power supply reliability continue to improve.

The ability of power science and technology innovation has been rapidly improved. At present, China has established a complete hydropower, nuclear power, wind power and solar power and other clean energy equipment manufacturing industry chain. In the first half of the year, China's exports of photovoltaic products totaled about 25.9 billion billion US dollars, up 113.1 percent year on year.

Despite the continuous consolidation of the power supply guarantee foundation, some periods and some areas still have tight supply. During the "14th Five-Year Plan" period, my country's electricity load and electricity consumption are expected to continue to grow, and it is necessary to further strengthen the power supply guarantee capacity; at the same time, in the process of low-carbon energy transformation, the new power system is still in the early stage of development., The lack of adaptability to large-scale high-proportion new energy connection and consumption and other challenges. To make up for these shortcomings, power infrastructure networking, network, strong chain has become an inevitable choice.

According to the person in charge of the relevant departments and bureaus of the National Energy Administration, for the construction of power infrastructure, networking mainly includes the development of UHV transmission channels, etc. The supplementary network mainly includes optimizing and improving the layout of the main power grid, strengthening the transformation and upgrading of urban distribution networks 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 safety and intelligent level of power infrastructure, making the power system more flexible, promote the coordination and interaction of source network storage. "Speeding up the interconnection, replenishment and strong chain of power infrastructure is an inevitable requirement to ensure national energy security and achieve the goal of carbon peak and carbon neutrality on schedule."

The focus of the construction of networking, network, strong chain, but also help to play the role of investment. In June, the State Grid announced that this year's power grid investment will exceed 500 billion yuan, reaching the highest level in history, and it is expected to drive social investment to exceed 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. This is the "intelligent brain" of the 10kV distributed power grid of China Southern Power Grid-the energy storage switching station. It can flexibly switch the distributed power grid between shutdown, grid-connected operation and off-grid operation. At the same time, it is like a big "charging treasure" and can store 2 MW of electric energy. According to reports, last year, the local built this "source (hydropower) network load storage" medium-voltage distributed power grid, can achieve full consumption of small hydropower, reducing about 43% of the abandoned water and electricity.

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

According to the person in charge of the relevant departments and bureaus of the National Energy Administration, the distributed smart grid takes the power grid as the basic platform, and actively adapts to the development of large-scale distributed new energy by improving the intelligent level of the power grid.

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

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 trend of centralized and distributed development. The "large clean energy base and large power grid" method mainly solves the problem of "electricity coming from afar", but long-distance transmission faces constraints such as investment cost, land, and environment. In order to promote the large-scale and high-proportion development of new energy, we also need to rely on distributed power supply to give full play to its advantages of being close to the load and being consumed nearby, so as to realize "taking electricity from around".

On the other hand, on the load side, it can support the electric vehicle charging pile, new energy storage, virtual power plant and other types of load subject access, to meet the diversified "plug and play" access needs.

"New energy output has the characteristics of intermittency, volatility, randomness, etc. With the continuous increase in the proportion of new energy, it is becoming more and more difficult to maintain the balance of the power system, and the problem of lack of flexible adjustment resources in traditional power grids is highlighted." Du Zhongming said that fine-tuning user power consumption through a 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.

"At present, it is the peak period of electricity price. It is suggested to charge the electricity price at 12 o'clock." At 10 a.m., Mr. Zhang, a teacher at the Hangzhou Institute of Advanced Studies of the National University of Science and Technology, originally planned to charge electric vehicles. After adopting the suggestions provided by the charging application, he saved about 70% of the electricity bill. Last year, Hangzhou Power Supply Company of the State Grid put into operation an intelligent collaborative project of "integration of optical storage and charging" in the school district, which includes distributed photovoltaic and energy storage power stations, 3 sets of fast charging piles, 20 sets of slow charging piles and a set of intelligent control system for optical storage and charging.

According to the data provided by the National Energy Administration, in recent years, the structure of my country'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, which fully guarantees the flexible access of various distributed power sources exceeding 0.1 billion kilowatts.

The development of distributed smart grid also requires efforts in key technologies and business models.

The interviewed experts believe that the development of distributed smart grids requires joint efforts in improving the "hardware" of key technologies and the "software" of business models.

At the key technical level, Du Zhongming believes that it is urgent to study the coordinated control technology adapted to massive distributed power supply and multiple load access, the intelligent power grid dispatching operation technology, and the key technology of digital and intelligent promotion of distributed smart grid.

As of the end of June this year, the number of pure electric vehicles in the country has reached 8.104 million, and the installed capacity of distributed photovoltaic power generation is 0.127 billion kilowatts, which is 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 charging load of superimposed electric vehicles increases sharply. The power balance and safe and stable operation of the system at the evening peak will face great challenges." Du Zhongming suggested that a technical support system for the integration of power distribution and electricity consumption should be built to open up the "last kilometer" of the distribution network connecting users ".

At the business model level, it is necessary to improve the price mechanism and market rules for "wall-to-wall electricity sales" (I. e., market-based transactions for distributed power generation). "The 'wall-to-wall market' helps to promote the nearby consumption of renewable energy, but the current 'grid fee' collection standard is not clear. How to balance the demands of the trading parties and grid enterprises, and improve the electricity price mechanism to support the spontaneous 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 departments and bureaus of the National Energy Administration told reporters that in the next step, the National Energy Administration will use 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, and significantly improve the power supply guarantee and flexible interaction of the distributed smart grid. Ability to achieve a more coordinated development of source network, load and storage.

One is to play the role of planning, strengthen the development of distributed smart grid planning and top-level design. Second, in areas with better demand response resources and rich new energy power generation resources, supported by distributed smart grids, distributed new energy power consumption is promoted through demand response according to local conditions. The third is to accelerate the research of distributed smart grid technology, and bring together research institutes, universities and enterprises to achieve core technology research.