UHV sub-DC UHV and AC UHV, the technical characteristics of both and its role in the power network vary widely, can not be confused. DC UHV for long-distance, high-capacity transmission, in the economic and technical obvious advantages. China's hydropower, wind power and solar energy resources are more concentrated in the western region, with long-distance transmission requirements, so the DC UHV as an advanced transmission technology is the construction of smart grid, green power in our country an indispensable means. This conclusion is clear and it has long been agreed. The controversial issue is the exchange of UHV. With the expansion of grid scale, the voltage level of power grids is continuously raised from low to high, which is indeed a common road that the development of power grids in various countries in the world have taken in over 100 years. Recalling the history is not difficult to see that the traditional power line technology route is to raise the voltage level approach to solve the problems arising in the development of power grids in order to meet the economic and social demand for electricity. But the development of things is not always a straight line, and some laws only play a role in one stage. Relying on increasing the voltage level to develop the power grid is based on fossil fuels, energy development tends to be more concentrated under the conditions formed, it can be said is the product of the second industrial revolution. When the new energy revolution, the third industrial revolution, took off in the world, the development of the power grid has actually departed from this route and embarked on a new path of building a smart grid. In the book "The Third Industrial Revolution," American futurist Jeremy Riddle introduced the views of the experts of the United States Electric Power Institute on the issue. According to U.S. experts, the development of decentralized smart grid energy production may take a route that closely follows the growth of the computer industry: mainframes allow for the miniaturization of geographically dispersed desktops and laptops that are interconnected, fully integrated, Become a very flexible network. Centralized power plants will continue to play an important role in the power industry, but small, clean and decentralized power plants will be needed and energy storage technologies will support their development; to control and process the resulting complex interconnected systems Bringing massive information and energy circulation problems, advanced electronic control technology is absolutely essential. It can be said that relying on advanced information, control, energy storage, superconductivity and other new technologies, focusing on the development of clean and decentralized renewable energy, pay attention to the use of new management concepts and techniques to improve energy efficiency and energy can be The sustainable development is the development route of the modern power grid (that is, the smart grid) shown by the third industrial revolution. As the distribution of renewable energy is relatively uniform, the result of decentralized development will make the layout of the power supply more reasonable; small power supply and microgrid can directly access the distribution network to supply users with lower voltage; in particular, the superconducting transmission technology The continuous improvement and more and more applications in the project show that the voltage level of the modern power grid not only does not increase or even decrease gradually on the basis of the ultra-high voltage. The voltage level of the power grid developed from low to high during the second industrial revolution and no longer increased after it entered the third industrial revolution and showed a trend of going from high to low. From the perspective of the entire development process, it is exactly The Negative Negation of the Development of Things. The view that the power grid will always follow the law of "growing scale and higher and higher voltage levels" is a metaphysical viewpoint lacking in dialectical thinking. Modern power grids are no longer developing into AC UHV grids, but also because ACHV itself has the following fatal flaws: ①environmental costs. Since the construction of AC UHV is to superimpose a 1000 kV power grid on the existing 500 kV power grid, the power rising to the power grid will be depressurized to 500 kV and then redistributed to 220 It can not only replace the 500 kV substation capacity and the corresponding 500 kV transmission line, but also increase the voltage level of China's power grid from the existing 5 levels to 6 levels (that is, to 0.4 / 10 / 110/220/500/1000 kV), making it the most voltage-level grid in the world. And the exchange of UHV noise, electromagnetic pollution on the environment than the ultra-high pressure, the power transmission equipment are monoliths, the need for more land area (double tower AC UHV tower with tower about 80 meters high, Corridor width of about 70 meters; an exchange of UHV substation covers an area of ​​9-20 hectares). Therefore, building UHV power grids means that as power grid complexity increases, it will also have to pay unbearable environmental costs for more power grids (especially in the densely populated "Sanhua" area). ② poor investment returns. AC UHV From a technical point of view, long-distance transmission is not as good as DC UHV, short-range transmission is not as good as 500 kV, but the investment is great, is a "low cost" program. China Southern Power Grid compared the use of AC UHV program and the use of UHV AC plus 500 kV AC power grid scheme were compared, the former investment than the latter 600-1000 billion yuan, about 1.3-1.5 times higher [5]. In the "Sanhua" area to build UHV AC power grid exchange program, than only to build DC UHV AC 500 kV grid asynchronous networking program, at least 300 billion yuan more investment. In addition to pushing up electricity prices, it also means consuming more steel, aluminum and cement, and the production of these high-energy-consuming products will undoubtedly increase the pollution of the environment. Pet Drinking Fountain ,Cat Drinking Fountain,Cat Water Fountains,Dog Drinking Fountain CIXI XINPU JIANKE ELECTRIC APPLIANCE FACTORY , https://www.cxjianke.com