Grasp the direction of modern grid development

The “Twelfth Five-Year Plan” is a very special period for the energy industry. During this five-year plan for national economic development, the state-level “12th Five-Year” national grid development plan is actually missing in the energy sector. There are two main reasons for this abnormality from the technical perspective: First, due to the lack of a profound understanding of the nature of AC UHV and smart grid, it has not been able to form a unified view on the development direction of China's power grid; There are some plausible grid planning theories that interfere with the preparation of the 12th Five-Year Plan.

This article will reflect on the lessons learned from the “12th Five-Year Plan” for power grids and analyze and clarify the basic principles of the two disparate and misunderstood power grid plans. Does the 13th Five-Year Plan develop an exchange UHV power grid and how to build a smart grid? How to grasp the development direction of China's power grid and other issues, put forward personal opinions and suggestions.

Two basic principles that need clarification and adherence

Divisional balance and reasonable grid structure are the two most basic principles that need to be followed in grid development planning. These two principles embody the essence of grid planning theory and are the magic weapon to ensure the security and economy of the power grid. They are also the touchstones for identifying the experts on genuine grid planning. For many years in carrying out high-voltage, large-capacity, long-distance transmission planning and construction, due to the lack of dialectical thinking, these two principles have been misinterpreted or diluted to some extent.

(I) Zoning is the most ideal power supply mode for the grid

Safety and economy are the most important and basic requirements for the power grid. The more the voltage level of a grid is, the farther the transmission distance of the electric power is, the greater the loss of electric energy and safety risks. The user's electricity voltage in the power grid is actually very low, the vast majority of users only 0.4 kilovolts, a few industrial users reach 10 kilovolts, but only one-fifth of the 500 kV ultra high pressure. Partitioning means that the power grid has a uniform layout, a low voltage level, a low level, and a short power transmission distance. As a result, the power consumption of the power grid is small, the investment is saved, the reliability of the power supply is high, and the impact on the environment is also small. . Obviously, this is the most ideal mode of power supply.

There is a view that due to the uneven distribution of China's energy resources and the need to optimize the allocation of resources within a larger area, the principle of zoning balance has become obsolete. The mistake of this view is that it does not see the essence of the problem and confuses two different levels of concepts. In fact, “zonal balance” reflects the specific requirements of the technical characteristics of the power grid, and “optimizing resource allocation in a wider range” reflects the general requirements of economic development. The two are not only contradictory but also have inherent complementarity. The ways to achieve optimal allocation of energy resources in a wider range include not only the way to build long-distance power transmission at the coal-based power plant, but also the way to transport coal to the load center to build a power plant over long distances. For the power grid, in order to reduce safety risks and improve energy efficiency, the latter is always better than the former as long as conditions permit. "Electricity comes from the side" is the result of the grid's desire, and "electricity comes from afar" is a last resort choice. Only when all roads on the road are blocked are the long-distance transmissions justified.