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If the 500 kV, 220 kV, 110 kV and below power grids are referred to as "low-to-medium level power grids," 1000 kV AC and ±800 kV DC UHV grids can be called "high-level grids."
At present, the “middle and low-level grids” with the main framework of the 500-kilovolt power grid constitute the “air corridor” of the vast land, which is beautiful and moving; and in the near future, the “high-level grid” will bridge the air in the earth. Corridor "is more beautiful and moving.
UHV power grid benefits a lot
UHV power grids have large transmission capacity, long transmission distance, low line loss, and occupy less land, which have many advantages.
The capacity of 1000 kV AC ultra-high voltage transmission lines to transport electrical energy (technically called transmission capacity) is five times that of a 500 kV EHV transmission line. Therefore, someone analogously stated that EHV power transmission is a provincial highway, and at most even a national road, UHV power transmission is a "electricity highway."
There is a term in the power engineering technology called "economical transmission distance", which refers to the most economical transmission distance of a voltage level transmission line, because the transmission line itself has losses while transmitting electric energy, and the line is too long to lose too much. Economically uneconomical.
The economic transmission distance of the 500 kV EHV transmission line is generally 600 to 800 kilometers, and since the voltage is increased and the line loss is reduced, the 1000 kV UHV transmission line will have an economical transmission distance that can reach 1,000 to 1000 kV. 1500 kilometers or even longer.
The construction of transmission lines will also occupy land, and the project is called "line corridor." The construction of a 1000 kV UHV transmission line can top 5 transmission capacities of 500 kV EHV transmission lines, while the land occupied by the “line corridor” is equivalent to only two 500 kV transmission lines, so relatively speaking, High voltage transmission lines can occupy less land.
The construction of UHV power grids can also firmly connect China's power grids so that different power plants (such as thermal power plants and hydropower plants) built at different locations can support each other and supplement each other. The project calls for "achieving mutual benefits through water and fire, and achieving “Networking benefits” can promote the intensive development of coal and water resources in the west and reduce the cost of power generation. It can ensure the growing power demand in the central and eastern regions and reduce the environmental pollution caused by the construction of thermal power plants in densely populated and economically developed regions. It can promote the harmonious economic and social development in resource-intensive and economically underdeveloped regions in the central and western regions.
Therefore, the construction of UHV power grids in the contemporary era will not be overstated.
Mainly by coal
Transfer power to coal transmission and change
At present, the province's power supply is mainly thermal power, with thermal power generation capacity and power generation accounting for 80% to 90% of the province's total. Coal power generation mainly depends on Shanxi, Shaanxi, and the “two Huai” regions. The long distance between coal and coal, and the tight supply of coal or transportation, will increase the energy risk. In recent years, at the time of peak winter and peak summer, Jiangxi power grid has been in short supply because of the coal problem.
As soon as possible, the special high-voltage power grids have been launched, and coal-to-coal transmission and transmission are the major transformations. This is a strategic choice, an overall concept, and a long-term perspective.
UHV transmission is conducive to saving investment and saving operating costs. From the experience of grid operation, high-level voltage transmission has obvious economic advantages over low-level voltage transmission. Research shows that, under the same conditions, the transmission capacity of a 1,000 kV UHV line and a 500 kV UHV line is 5 times higher than that of the latter, and the former is 73% of the latter. about. In addition, the resistance loss of a 1000 kV line is about 1/4 of that of a 500 kV line when the total cross section of the wire and the transmission capacity are the same. Therefore, UHV transmission can significantly reduce line losses and reduce the cost of power grid operation.
UHV transmission will help reduce the pollution of coal-fired power to the densely populated areas in Jiangxi. With the development of industry, the environment in which people depend on is increasingly polluted. In order to solve the environmental pollution problem of thermal power plants, China has invested a great deal of financial and material resources to transform existing thermal power plant dust removal, desulfurization, and removal of ash and other equipment. Clean coal-fired technology is used for new power plants. These measures reduce the degree of pollution of the environment. However, due to the fact that the environmental capacity of densely populated areas has become saturated, if new coal-fired power plants are combined with the pollution generated from coal transportation, the environment in densely populated areas will be overwhelmed. Using UHV power transmission to send electricity to densely populated load centers can reduce pollution to densely populated areas, reduce the pressure on environmental capacity in densely populated areas, and reduce emissions from long-distance power generation coal used in railway and road transport to the atmosphere. Environmental pollution. In other words, the transmission of electricity is much smaller than that of coal transportation. UHV transmission will help reduce the pollution of coal-fired power to the densely populated areas in Jiangxi.
UHV transmission can meet environmental protection requirements. Through reasonable design and adoption of a series of environmental protection technology measures, UHV transmission complies fully with environmental standards. For example, the environmental protection technology of 500 kV transmission lines is used to increase the height of towers, the use of all-round high and low leg design for pole and tower foundations, reverse phase sequence for double towers on the same tower, compact lines, new heat-resisting and expanding conductors, and large cross-sections. Harvard technology and other measures are used to select the conductors and circuit paths. The study of the effects of 1000 kV transmission on the electromagnetic environment shows that after these measures are taken, the level below the transmission line, across the highway and adjacent residential buildings is exactly the same as the 500 kV line, and the power frequency magnetic field is far below the maximum specified by current environmental protection standards. Values, radio interference and audible noise comply with the corresponding national standards.
When the wind breaks through the waves, Yunfan sails to the sea. We believe that with the passage of a "new corridor in the sky", the beautiful and moving vast landscape will be full of charm and vitality!