With the large-scale development of new energy, the proportion of new energy generation in the power grid is constantly increasing, and the system power balance, safety and stability control are facing an unprecedented situation. The urgent need to promote the transformation of clean and low-carbon energy and help achieve the "double-carbon" goal also calls for the construction of a new power system with more powerful functions, more flexible operation and more resilience.

Recently, in the new power system seminar of North China Electric Power University 2023, the participating experts proposed that at present, in the process of building a new power system, the transformation of power supply characteristics and regional development differences and other issues need to be paid attention to.

■■ New type of electric power system

Facing many aspects of changes

From the basic characteristics of the new power system, the experts at the meeting pointed out that its power structure, power positioning, power form, power supply characteristics have changed.

"In terms of power supply form, various forms of power supply coexist, and new energy cluster, scenery, water and fire storage, new energy + energy storage, new energy + hydrogen energy, new energy + hydro-power, new energy + charge + energy storage will emerge. In terms of power supply characteristics, under the existing technology, the power supply is more complex and volatile, and new energy varieties with stable performance are needed in the future."China Southern Power Grid Energy Development Research Institute Co., LTD. Assistant researcher Zhou Huansheng pointed out.

After the new energy gradually becomes the main power supply, the role of the resource optimization allocation platform of the power grid will be more prominent. Zhou Huansheng further said that the digital power grid may become the * * * * * * form carrying the new power system, play the role of resource optimization allocation, and promote the coordination of source network, load and storage."The structure of the power grid will develop from the traditional large power grid interconnection to the flexible interconnection form of 'backbone network + small and medium-sized power grid and micro power grid', forming a clear and reasonable, stratified and divided transmission network structure. The distribution network will also have more efficient flexibility and initiative, energy storage load open access and two-way interaction.”

As an indispensable element and prominent feature of the new power system, the access of energy storage brings challenges to the security and dispatching operation of the power grid."Therefore, the planning, scheduling and control technology of energy storage is also a major problem to be studied and solved urgently. At present, domestic energy storage has a high cost, serving a single object, low economy and utilization efficiency; as a new element of new power system, energy storage faces many objects, but the business and interaction relationship with each object lacks perfect and detailed operation strategy and settlement mechanism; energy storage intelligent decision-making ability is insufficient, and operation and control depend on personnel regulation, which increases the workload and responsibilities of relevant personnel."Yunnan Power Grid Co., LTD. Electric power Academy of Sciences Research Institute specialist Zhai Suwei said.

■■ Urban and rural electric power system construction

Each has its own emphasis

The regional difference of power system development in rural and urban areas is also an important factor to be considered in the construction of new power system in the future.

The "No.1 Central Document" released at the beginning of this year clearly proposed to promote the consolidation and upgrading of rural power grids, develop rural renewable energy, and encourage areas where conditions permit to develop new energy vehicles and green smart home appliances to the countryside.

The construction of rural clean energy system needs to develop distributed new energy grid, but the current capitalization level and digital level of rural power grid.

Building a clean energy system in rural areas requires the large-scale development of distributed new energy grid connection, but there is still a certain gap between the current capitalization and digitalization levels of rural power grids and this requirement. "The current transformation towards a modern rural power grid is not only facing the growth of power supply load, but also the problems brought about by large-scale distributed energy access. The coverage of rural power grids is relatively wide, personnel operation and maintenance are difficult, and the carrying capacity of new energy is poor." Qin Huiling from the Grid Planning and Research Center of Guangxi Power Grid Co., Ltd. pointed out, "Specifically, during the '13th Five Year Plan' period, although we upgraded and renovated the rural power grid, we mainly focused on infrastructure such as per capital capacity and reliability indicators of power supply. Entering a new stage of development, it is not only required that the rural power grid assist in the development of rural industries, but also comprehensively serve ecological goals and build a clean energy system in rural areas."

These all pose new requirements for the construction of the power grid. Qin Huiling believes that in the future, modern rural power grids can be built through intelligent enhancement, enhanced perception ability of rural distribution networks, enhanced capacity for new energy consumption, and digital empowerment.

The Director General of the New Power System Construction Office of State Grid Beijing Electric Power Company stated that with the deepening of the new energy system under the "dual carbon" goal, new formats and models of China's digital economy are flourishing, and the outline of Beijing's urban sub center during the green development path is gradually becoming clear. It is urgent to take the construction of the new power system as the lead to support the green transformation of traditional energy systems.

"Based on the digital low-carbon urban power grid, we can promote multi energy complementarity and electricity substitution on the basis of comprehensive utilization of multiple energy sources such as electricity, gas, heat, and oil, gradually realizing the transformation from energy consumption dual control to carbon emissions dual control. In terms of all elements of source network load storage, we will carry out technological, mechanism, and mode related innovations to promote coordinated interaction between source network load storage."

■■Demonstration project

Providing reference experience

For the follow-up construction of modern rural power grids, Qin Huiling believes that the country has put forward requirements for the direction of modern rural power grid construction, but there is still a lack of specific quantitative indicators. She suggested that in the future, we should consolidate the level of rural electricity security, continue to increase investment, and gradually narrow the gap in the average power supply level of rural power grids in different regions. At the same time, we should improve the level of rural grid structure and clean energy consumption capacity, and enhance the digitalization and electrification level of rural power grids.

Based on the resource endowment and construction infrastructure of various provinces and regions, Southern Power Grid is also laying out a number of new power system demonstration zones, and orderly promoting the construction of demonstration projects at the provincial, prefecture, county, and park levels. Among them, in the demonstration of distributed photovoltaic grid connection, in order to solve the problems of high voltage, harmonics, and three-phase imbalance at the end of the distribution network caused by the large number of distributed photovoltaic connections on the roofs of buildings such as urban and rural areas, Guizhou has constructed the flexible distribution network demonstration project in Yangchang Township, Liupanshui. The project adopts technologies such as AC and DC pole installation, flexible interconnection of substations, distributed photovoltaic+energy storage, and on load capacity and voltage regulation, achieving good results. "After the implementation of the project, the average annual power outage time has been reduced from 0.17 hours per household to 0.12 hours per household, the voltage qualification rate has been increased from 99.91% to 99.94%, the self-healing rate of medium voltage lines has been increased from 50% to 87%, and the distributed photovoltaic consumption rate has reached over 70%," said Zhou Huansheng.

In terms of green and low-carbon, according to He Jiaxing, a senior engineer from the Marketing Department of Guangzhou Power Supply Bureau of Guangdong Power Grid Co., Ltd., as one of the low-carbon pilot cities in ****************************, Guangzhou has built "Sui Carbon Calculator" WeChat Mini Program, "" Sui Carbon "Electricity Carbon Big Data Platform," Sui Carbon "Industrial Green Finance Platform, Guangzhou Industrial Park Information Service Platform," Sui Carbon "Green and Low Carbon Service Platform, etc, The low-carbon demand and supply capacity of interconnected government, enterprise, industry and finance sectors, empowering various application scenarios with digital technology.

In terms of energy storage, Zhai Suwei believes that the operation and control of energy storage should further consider the collaboration between the power grid and users. "There should also be more trading mechanisms for energy storage to participate in grid regulation. At the same time, energy storage should be fully distributed and utilized with functions such as multi use at one station and time-sharing reuse to improve utilization efficiency." (Source: China Energy News)