Voltage level
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Voltage class (voltage class) The rated voltage class series of power systems and power equipment. The rated voltage is the normal voltage specified by the power system and power equipment, that is, the nominal voltage related to certain operating characteristics of the power system and power equipment. The actual operating voltage of each point of the power system is allowed to deviate from its rated voltage to a certain extent. Within this allowable deviation range, various power equipment and the power system itself can still operate normally.
The Chinese name of voltage class The foreign name of voltage class is used in power systems and power equipment to define the rated voltage levels of power systems and equipment
table of Contents
1 category
2 Suitable transmission distance and power for different voltages
3 Reasonable configuration of urban power grid voltage levels
General division of voltage levels:
1: Safety voltage (usually below 36V);
2: Low voltage (divided into 220V and 380V);
3: High voltage (10KV-220KV);
4: Ultra-high voltage 330KV-750KV;
5: UHV 1000KV AC, ±800KV DC or more;
The highest AC voltage level in my country is 1000kV (Changzhi-Jingmen line), which was put into operation on December 30, 2008. Transmission lines under construction (Xiangjiaba-Shanghai, Jinping-Sunan UHV DC 800kV), under which there are 500kv, 330kv, 220kv, 110kv, 66kv, 35kv, 10kV, 380/220V, of which 60kV is left over due to historical reasons The ones that come down only exist in the northeast of my country;
The highest DC voltage rating in my country is ±800kV (South Hami-Zhengzhou, Xiangjiaba-Shanghai, Jinping-Southern Jiangsu, Xiluodu-West Zhejiang, Lingzhou-Shaoxing), ±660kV (East Yinchuan-Jiaodong), ±500kV (Gezhouba —Shanghai Nanqiao Line, Tianshengqiao—Guangzhou Line, Guizhou—Guangdong Line, Three Gorges—Guangdong Line), plus ±50kV (Shanghai—Shengsi Islands Line), ±100kV (Ningbo– -Zhoushan Line), China Southern Power Grid has built a ±800kV UHV DC transmission line-Yunguang UHV DC transmission line, and the State Grid Corporation has built two ±800kV UHV DC lines, namely Xiangjiaba-Shanghai ±800kV UHV DC line and Jinping-Sunan ±800kV UHV DC line.
Commonly used voltage levels in my country: 220V, 380V, 6.3kV, 10kV, 35kV, 110kV, 220kV, 330kV, 500kV, 1000kV. The power system is generally composed of power plants, transmission lines, substations, distribution lines, and electrical equipment. Generally, voltage lines above 35kV are called power transmission lines.
Voltage lines of 35kV and below are called distribution lines. The voltage above 1kV is called “high voltage”, and the voltage below 1kV is called “low voltage”.
my country stipulates five safety voltages: 42V, 36V, 24V, 12V, and 6V.
Among the AC voltage levels, 1kV and below are usually called low voltage, 1kV and above, 35kV and below are called medium voltage, 35kV and above, 220kV are called high voltage, 330kV and above, and 1000kV are called ultra-high voltage, and 1000kV and above are called special voltage. high pressure.
Among the DC voltage levels, ±800kV is called high voltage, and ±800kV and above is called UHV [1].
Suitable transmission distance and power for different voltages
Voltage level Transmission distance KM Transmission power KW
0.4KV   0.6 or less   100 or less
6.6KV   4~15  100~1200
10KV  6~20   200~2000
35KV   20~70   1000~10000
66KV   30~100   3500~30000
110KV  50~150   10~50MW
220KV   100~300   100~ 500MW
330kV  200~600  200~800MW (Northwest)
500KV  150~850  1000~1500MW
750KV  more than 500  2000~2500MW
1100KV 1000~1500 3000MW and above [1]
Reasonable Configuration of Voltage Level of Urban Power Grid
(1) With the increase of load, the adaptability of the voltage level sequence currently used in some areas of my country is limited, and it is necessary to adopt a new voltage level sequence. The implementation of the voltage level configuration requires an in-depth feasibility study according to the specific conditions of the city.
(2) For areas with higher final load density, a gradual transition to a higher medium voltage distribution voltage can be considered. For areas with lower final load density and longer power supply distances, higher medium voltage distribution voltages can also be considered.
(3) In order to avoid affecting the reliability of power supply during the introduction of new voltage levels, the installation of tie transformers can be used to connect power grids with different distribution voltage levels to the grid.
(4) For areas where the new voltage level sequence is adopted, the internationally accepted method of gradual cannibalization can be adopted. After several years of gradual transition, a target voltage level sequence mode can be formed. [2]