In order to achieve the goals of carbon peak and carbon neutral, the new power with a high share will be connected to the new generation of power system and sent to thousands of households, so as to improve the proportion of green power in the terminal power consumption. Together, in order to achieve the citizens' aspiration for a better life, more new energy use scenarios will emerge, and many sensitive loads such as electric cars will be connected to the user side. The distribution network will play an important role, and transformation and upgrading will become inevitable. Moreover, as China deepens the promotion of a new round of electricity reform, including incremental distribution business reform, 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 the State Grid Tianjin Electric Power Company, completed live lead 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 multiple power supply, "hand in hand" power supply, from automation to the completion of intelligent patrol inspection, from the cancellation of planned power outage to the deep integration of distribution network with 5G, artificial intelligence and other technologies, and the development elements are increasingly diverse.
With regard to the development trend of the distribution network in the future, the interviewees generally believed that with the transformation and upgrading of the power grid, the capacity of sensitive loads such as distributed power generation, electric vehicles, energy storage and so on 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.
Progress in the proportion of new load
The construction of China's power system has been "putting more emphasis on power generation than on power supply", and the construction of distribution network has been lagging behind for a long time. In recent years, along with the continuous improvement of the distribution network automation coverage and practical level of power grid companies around the country, the distribution network is accelerating its transformation to an active and inductive power network. "With the continuous progress of user demand, the traditional distribution network with the goal of geographical full coverage of power supply of user load is gradually changing to the distribution network with the goal of green, intelligent and customizable power supply services." An industry person who refused to sign said this when commenting on the development of distribution network.
In the view of Professor and Jing Han of the School of Electrical Engineering of Beijing Jiaotong University, the traditional distribution network mostly uses the single-point to multi-point radial single-direction power transmission structure, and takes the superior substation as the power source. The respective roles and positions of "source-network-load" are very clear.
In the future, many distribution networks will be connected to distributed power sources and sensitive loads to adapt to customized power supply requirements. The boundary area of "source-network-load" character positioning and behavior characteristics is vague and the level is increasingly rich. Together, the barriers between its external and transportation, communication and other areas will be gradually broken.
"In the future, the distribution network will not only bear the power supply demand of the transmission network, but also undertake the power transmission and consumption responsibilities of more local distributed power sources." Wu Junhong, director of the Smart Power Room of the East China Electric Power Planning Institute, said in an interview with a reporter that from the functional positioning of the traditional power system "generation, transmission, transformation, distribution and use", it can be seen that the distribution network has assumed the function of the transmission network to reduce voltage and deliver power to users in the past, This is inseparable from the idea of developing the power system in the past. However, with the technological progress and power innovation requirements, there will be more and more emerging power businesses represented by distributed power generation, and the interconnection will be completed through the distribution network.
He Jinghan also believes that under the new infrastructure setting, the new load is becoming more and more diversified. For example, in terms of 5G base stations, it is expected that there will be 5-6 million 5G base stations by 2025. The power consumption and broadband utilization ratio will fluctuate with high daily and low night and high and low traffic density; As a mobile distributed energy storage device, electric vehicles in China will have a year-on-year increase of 128% in 2019, and it is expected that the electric capacity of charging and replacement services will exceed 50 billion kWh in 2025. It can be predicted that the complexity of distribution network operation will be significantly increased in the future with the progress of the proportion of new loads with high randomness, high sensitivity and high reliability.
"In the past, the distribution network has a strong dependence 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 said that in addition to the power current load, the future distribution network will also give full play to the effect of the power information flow carrier, serving intelligent power, user interaction and other power value-added services.
We need to introduce social capital to make technological innovation
As we all know, distribution network has gradually become the "big contributor" of power grid in recent years. Active distribution network, microgrid, AC/DC hybrid distribution network, etc. have made essential progress, but it cannot be ignored that in the process of building a new generation of power system, distribution network is still one of the weak links of the whole system, especially the distribution network protection is facing many challenges.
He Jinghan shows that the rapid increase of distributed power supply, DC distribution network, energy storage equipment and power electronic equipment has led to the increasingly complex 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 power generation equipment are connected, generating power has randomness and volatility, and fault current size and direction are variable; The appearance of new networks such as DC distribution network, changes in network structure and operation methods, and different fault characteristics require research and development of corresponding protection measures.
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 function positioning of the distribution network; Capital pressure under the service objectives of "three provinces" (labor saving, time saving and money saving) and "three zeros" (zero door-to-door, zero approval and zero investment) for distribution network transformation and power optimization business environment; The solution to the institutional pressure on the openness of the distribution network is to further open up the mind, innovate the financing forms, introduce social capital, and do a good job of technological innovation.
Adhere to the principle of user value and output benefit
According to the interviewees, the distribution network is connected to the main grid and thousands of households, which is an important link to connect the transmission network, distributed power and various users. It can be said that "strong distribution network leads to strong power". Now, with the rapid development of science and technology, the distribution system has shown a diversified development trend. Compared with the transmission network, the development of distribution network has more potential.
Wu Junhong analyzed that from the perspective of the investment structure of the power grid, with the increasingly saturated construction of the transmission network, its construction space is increasingly limited, especially in the economically prosperous areas such as the Yangtze River Delta. In contrast, there is a lot of space for the construction of the primary distribution network or the intelligent construction of the secondary distribution network; From the perspective of the development of power industry, under the background of power innovation with the national strategic carbon reduction goal of carbon peak and carbon neutral as traction, 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 the two-way power flow operation form, In order to improve the safety and reliability of the power grid, it is also necessary to vigorously develop the distribution network; From the perspective of market openness, under the general goal of power system reform, the distribution network that has reached the conditions of incremental distribution affairs has been released to social capital investment, and the investment vitality and innovation of distribution network are unprecedented.
In addition, in the context of 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 according to the characteristics of local development, so as to achieve the combination of far and near, and overall consideration, and essentially improve the construction, operation and maintenance, and management level. "Power grid enterprises should focus on the development of goals and transaction logic, and should not blindly seek high reliability or differentiation. Intelligent distribution networks or the distribution network of things can be divided into two types of transactions in the final analysis. One is the control of power distribution transactions and the recovery of related investment costs through the transmission and distribution price. Considering the severity of the transmission and distribution price control and the affordability of the user's electricity price, the demand for such transactions should be balanced between the capital investment and the reliability improvement effect; and One is market service affairs. This kind of investment needs to grasp the needs of the buyer and build on the basis of the value of the invention user and the output benefit. " Wu Junhong suggested.