Prediction and Analysis of the Development Prospect of Power Network and Power Grid in China

From the late 20th century to the beginning of this century, accompanied by the exacerbation of global climate change and the depletion of traditional energy sources, a new energy revolution quietly emerged. Energy conservation, raising the level of clean and efficient use of fossil fuels, replacing fossil fuels with renewable energies, and achieving renewable energy sources Clean energy such as hydroenergy, wind energy, solar energy, geothermal energy, biomass energy and nuclear energy, etc. In primary energy production and consumption Taking a larger share and building a sustainable energy system are the main goals of this new energy revolution. The vast majority of the clean utilization of renewable energy, nuclear energy and fossil fuels must be achieved by conversion to electricity. Under the condition of new energy revolution, the importance of power grids has become increasingly prominent, and the power grid will become an important energy transmission and distribution network in the whole society. Compared with the traditional power grid, the future change of the power grid mission mainly includes the following four points: 1 to receive large-scale centralized and distributed renewable energy power to become the new energy power transmission and distribution network; 2 and distributed power supply, energy storage device , The integrated and efficient energy utilization system is organically integrated and the two-way interaction is made to improve the terminal energy efficiency and become a flexible and efficient smart energy network. 3 It has extremely high reliability of power supply and basically eliminates the risk of large-scale power outage and becomes a safe and reliable energy source Supply system; 4 with a wide range of information and communication systems, a collection of energy, electricity, information as one integrated service system. Power Grid The power grid in a broad sense, as a product of modern industrial civilization, has undergone more than 100 years of development. Looking at the history of the development of the world power grid and future changes in the mission of the power grid, according to the different stages of the main technical and economic characteristics of distinction, can be divided into three generations of power grids. The first generation of grid was a small power supply, low voltage, small power grid before World War II, is the rise of the grid. The second generation grid is a large unit developed from the end of World War II to the end of the last century. The ultra-high voltage and large-scale interconnected power grid are the large-scale development stages of the grid. The second generation grid relies heavily on fossil fuels, and the safety risks of large power grids are hardly eliminated. This is an unsustainable grid development model. The future power grid is the third generation grid. The third generation grid is the first and second generation grids in the new energy revolution under the conditions of heritage and development, support for large-scale new energy and electricity, substantially reduce the security risks of large power grids, and extensive integration of information and communication technology is the grid's sustainable, Intelligent development stage. At present, China's energy and power are facing a new stage of development and transformation. From now till 2050, it will be the transitional period for China's power grid to transform from the second generation to the third generation. In line with the transformation of power supply, the development of power grid will generally be a combination of national backbone transmission network and local transmission and distribution network and micro-grid, which can adapt to both large-scale and renewable energy sources such as hydropower, wind energy and solar power generation and clean The demand for power transmission, optimization and intermittent power mutual compensation in centralized power generation bases such as coal-fired power plants and nuclear power plants can also meet the demand for opening up distributed power sources, promoting the development of micro-grids, and improving the energy efficiency of terminals. Between now and 2030, China's power transmission backbone network will basically maintain its UHV / UHV AC / DC transmission network mode, that is, the transmission backbone network from 2020 to 2030 should be super-large-scale UHV AC / DC Mixed complex grid. Multi-terminal DC transmission technology, FACTS and VSC-HVDC and other power electronics technology will be more widely used, energy storage technology is likely to make significant progress, laying the technical foundation for the transformation of the post-grid. From 2030 to 2050, with the large-scale hydropower in Southwest China, large-scale wind power in western and northern regions, giant desert solar power stations and the centralized development of renewable energy such as offshore wind power in the east coastal areas, the proportion of intermittent and fluctuating power sources has been continuously raised. Building a trans-regional transmission network with flexible controllability, low loss and high reliability nationwide will be necessary for optimal allocation of large-scale resources and mutual compensation. At this stage, the accumulation and breakthrough of technological development may have a revolutionary impact on the transmission network model. According to the different degree of technological breakthrough, there may be two modes: one is to continue the current development of ultra / UHV AC and DC transmission network mode; the second is the HVDC transmission network superconducting or conventional conductor mode. The latter is more dependent on major breakthroughs in relevant advanced technologies, necessity and technical and economic superiority. During this period, the multi-terminal HVDC transmission network based on high-performance power electronic equipment has matured. It is possible to make new breakthroughs in high-temperature superconducting transmission technology. In order to build a super-high-voltage transmission line based on conventional conductor circuits and equipment or based on high-temperature superconducting circuits and devices DC transmission network to provide technical conditions. In the future, the transformation of energy and power structure will have a more significant impact on the development of power distribution system. The external environment of distribution network operation has the following salient features: 1 A large number of EV charging and discharging facilities will access the power distribution system; 2 Distributed Power supply, energy storage system and micro-grid will exist on a large scale in the power distribution system; 3 energy consumption mode will change due to the establishment of flexible interaction mechanism between user and power distribution system; 4 power distribution system will become power, energy , Integrated information technology services platform; 5 advanced information networks, sensor networks and Internet of Things will be widely used in power distribution systems. Based on the above trend of grid and grid technology development and the demand of constructing the third generation power grid, 10 key technologies that must be studied in the near future are put forward: 1 large-scale renewable energy and power-friendly access technologies are distributed; 2 High-capacity transmission technology; 3 advanced sensor network technology; 4 power communications and information technology; 5 large-capacity energy storage technology; 6 new power electronics and application technology; 7 advanced grid dispatching, control and protection technology; 8 advanced computing power system Simulation technology; 9 smart distribution network and micro-grid technology; 10 smart power technology. In view of the smart grid related issues discussed in the Xiangshan meeting in 2011, the conference focused on the central theme of the future grid development mode, the new transmission mode and transmission lines, superconducting power and its development prospects, the power storage system in the future Technology, new power electronic technology devices and equipment, new transmission and distribution equipment technology and so on. The development of these new technologies will have a significant impact on the future development of the power grid.