In order to achieve the goals of carbon peak and carbon neutralization, high share of new power will be connected to the new generation of power system and sent to thousands of households. In order to improve the proportion of green power in terminal power consumption, more new energy consumption scenarios will emerge to complete citizens' longing for a better life. Many sensitive loads such as electric vehicles will be connected to the user side. The distribution network will play an important role, and transformation and promotion will become inevitable. Moreover, with the deepening of China's new round of power reform, including the reform of incremental distribution affairs, more profits will benefit the whole society.




Recently, a new generation of artificial intelligence live working robot for distribution network developed by Zhang Liming, the "pioneer of change" of State Grid Tianjin electric power company, has completed live wire connection, which is another technological innovation in the field of distribution network. It is understood that in the process of building a new generation of power system, local power grid companies, including Tianjin electric power, continue to explore new technologies of distribution network, from single power supply to multi power supply, "hand-in-hand" power supply, from automation to intelligent inspection, from canceling planned power outage to the in-depth integration of distribution network with 5g, artificial intelligence and other technologies, and the development elements are becoming more and more diverse.




With regard to the development trend of distribution network in the future, people in the industry interviewed generally believe that with the transformation and upgrading of power grid, the capacity of sensitive loads such as distributed generation, electric vehicles and energy storage connected to the distribution side is increasing, and the distribution network will have broad development potential and become the center of the new generation of power system.




The proportion of new load has improved




The construction of China's power system once "heavy power generation and light power supply do not work", and the construction of distribution network has lagged behind for a long time. In recent years, as local power grid companies continue to improve the automation coverage and practical level of distribution network, the distribution network is accelerating the transformation to active and inductive power mutual assistance power grid. "With the continuous progress of user demand, the traditional distribution network aiming at the geographical full coverage of user load is gradually changing to the distribution network aiming at green, intelligent and customizable power supply services." An insider who refused to sign said this when commenting on the development of distribution network.




According to Professor He Jinghan of the school of electrical engineering of Beijing Jiaotong University, most traditional distribution networks use single point to multi-point radial unidirectional power transmission structure, with the superior substation as the power supply, and the respective characters and positioning of "source network load" are very clear.




In the future, many distribution networks will be connected to distributed power sources and sensitive loads to get used to customized power supply demand. The boundary areas and levels of "source network load" character positioning and behavior characteristics are vague and richer. Together, the external barriers to transportation, communication and other fields will be gradually broken.




"In the future, the distribution network will not only bear the demand for step-down power supply of the transmission network, but also bear the responsibility of more local distributed generation power transmission and consumption." In an interview with reporters, Wu Junhong, director of the smart power office of East China Electric Power Planning Institute, showed that from the functional positioning of "generation, transmission, transformation, distribution and utilization" of the traditional power system, it can be seen that in the past, the distribution network undertook the function of reducing voltage and transmitting power to users of the transmission network, which is inseparable from the development ideas of the power system in the past. However, with the requirements of technological progress and power innovation, there will be more and more emerging power formats represented by distributed generation, which will be interconnected through the carrier of distribution network.




He Jinghan also believes that under the background of the new infrastructure, the new load is becoming more and more diverse. For example, in terms of 5g base stations, it is expected that there will be 5-6 million 5g base stations by 2025, with the fluctuation of high power consumption and low broadband utilization ratio, high day and low night and high density of people; As a mobile distributed energy storage device, the electric vehicle charging and replacement service power in China increased by 128% year-on-year in 2019. It is expected that the charging and replacement service power will exceed 50 billion kwh in 2025. It can be predicted that in the future, with the improvement of the proportion of new loads with high randomness, high sensitivity and high reliability, the operation complexity of distribution network will be significantly improved.




"In the past, the distribution network was highly dependent on the transmission network. In the future, there may be a weak connection between the distribution network and the transmission network, and even support the transmission network in turn." Wu Junhong showed that in addition to the power current carrier, the future distribution network will also give full play to the effect of power information flow carrier to serve smart power, user interaction and other power value-added services.




We need to introduce social capital to make technological innovation




As we all know, the distribution network has gradually become the "big head" of power grid investment in recent years, and essential progress has been made in active distribution network, microgrid and AC / DC hybrid distribution network. However, it can not be ignored that in the process of building a new generation of power system, the distribution network is still one of the weak links of the whole system, especially the protection of distribution network is facing many challenges.




Hejinghan shows that the rapid increase of distributed generation, DC distribution network, energy storage equipment and power electronics equipment leads to the increasing complexity of distribution network architecture, operation methods and fault characteristics, and the traditional fault analysis methods and protection plans are difficult to get used to. For example, many distributed generation equipment are connected, the generation power has randomness and fluctuation, and the size and direction of fault current are changeable; New networks such as DC distribution network appear, the network structure and operation methods change, and the fault characteristics are different. It is necessary to study and carry out corresponding protection methods.




Wu Junhong believes from the macro level that China will encounter various pressures in the process of changing the traditional distribution network: the conceptual pressure of changing the functional positioning of the distribution network; Capital pressure under the service objectives of "three provinces" (labor-saving, time-saving and money-saving) "three zero" (zero door-to-door, zero approval and zero capital contribution) for distribution network transformation and power optimization business environment; The solution to the institutional pressure on the openness of distribution network is to further open your mind, innovate financing forms, introduce social capital, and do a good job in technological innovation.




Adhere to the principle of user value and output benefit




Industry insiders interviewed believe that the distribution network is connected to the main grid and thousands of households. It is an important link to connect the transmission network, distributed power generation and all kinds of users. It can be said that "if the distribution network is strong, the power is strong". Nowadays, with the rapid development of science and technology, the distribution system presents a diversified development trend. Compared with the transmission network, the development of distribution network has more potential.




According to Wu Junhong's analysis, from the perspective of the investment structure of the power grid, with the increasingly saturated construction of the transmission network, its construction space is becoming more and more limited, especially in economically prosperous areas such as the Yangtze River Delta. In contrast, there is a lot of space for both the construction of the primary distribution network and the intelligent construction of the secondary distribution network; From the perspective of power business development, under the background of power innovation driven by carbon peak, carbon neutralization and national strategic carbon reduction goals, there are considerable planned distributed renewable power, electric vehicles, user side energy storage and other equipment needs to be connected to the distribution network, which puts forward higher requirements for the carrying capacity and intelligence of the distribution network. Together, the distribution network will also be changed from the traditional one-way power flow operation form to two-way power flow operation form, In order to improve the safety and reliability of power grid, we must also vigorously carry out distribution network; From the perspective of market openness, under the overall goal of power system reform, the distribution network that reaches the conditions of incremental distribution affairs has been liberalized to contribute to social capital, and the investment vitality and innovation of distribution network are unprecedented.




In addition, under the background of power grid transformation and promotion, the distribution network will also be transformed into a smart power system. The transformation and promotion of local distribution networks need to be planned in combination with the characteristics of local development, so as to achieve the combination of distance and distance, make overall consideration, and essentially improve the level of construction, operation and maintenance and management. "Power grid enterprises should focus on the development objectives and transaction logic, and should not blindly seek high reliability or independence. In the final analysis, intelligent distribution network or distribution Internet of things can be divided into two types of affairs. One is controlled distribution affairs, and the relevant capital contribution costs are recovered through transmission and distribution price. Considering the severity of transmission and distribution price control and the affordability of user price, the development needs of such affairs should balance between capital investment and reliability improvement effect; the other is One is market-oriented service affairs. This kind of investment should grasp the needs of the buyer and build according to the principle of inventing user value and output benefit. " Wu Junhong suggested.
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