1. the concept of transmission (transmission) lines
Transmission (transmission) line is connected to the power plant and substation (office) of the transmission of electricity power lines.
2. the voltage level of transmission lines
Domestic: 35kV, 66kV, 110kV, 220kV, 330kV, 500kV, 750kV, ± 80okV.1000kV.
Province: 35kV,110kV,220kV,500kV,±8ookV
3. Categorization of transmission lines
(1) according to the nature of the transmission current: AC transmission lines, DC transmission lines.
(2) according to the structure: overhead transmission lines, cable lines.
Composition of the main components of the overhead transmission line: conductor, lightning line (referred to as lightning line)
Fittings, insulators, towers, wires and foundations, grounding devices.
The tower of the overhead line is generally based on its material, use, the number of conductor circuit, structural form and so on.
4. Classification
(1) According to the material classification: reinforced concrete poles, steel poles, angle steel tower, steel tower.
(2) According to the use of classification: linear (pole) tower, tension-resistant (pole) tower, divergent (pole) tower, straight line, small corner (pole) tower. Small corner (pole) tower, across (pole) tower.
(3) According to the number of circuits to be categorized: single circuit, double circuit, three circuits, four circuits, multiple circuits.
(4) Classified by structural form: tie-line tower, self-supporting tower, self-supporting steel tower.
5. Problems of single-circuit transmission lines.
In economically developed and densely populated areas, land resources are very scarce, only the construction of single transmission line.
The construction of single circuit transmission lines can no longer meet the demand for electricity.
Multi-turn lines with the same tower is an effective means to improve the transmission capacity of the line corridor, which can not only increase the transmission capacity per unit area of the line, but also increase the capacity of the line.
Road unit area of transmission capacity, increase power delivery, but also reduce the overall cost.
In Germany, the government stipulates that all new lines must be erected on the same tower for more than two times. In the high-voltage ultra-high-voltage line
Road, for the same tower four times for conventional lines, up to six times. As of 1986, the same tower and frame multi-return compact line length is about 2,000 meters.
As of 1986, the total length of multi-turn compact lines with the same tower was about 27,000km, and there has been more than 50 years of operation experience.
In Japan, most of the lines of 110 kV and above are four circuits with the same tower, and the 500 kV lines are all single circuits with the same tower, except for two early ones.
500kV lines, except for two single-circuit lines in the early days, are all double circuits on the same tower. At present, the maximum number of circuits on the same tower in Japan is eight.
In recent years, with the accelerated construction of power grids, Guangdong and other regions with the same tower multi-circuit application is also relatively and has gradually become a mature technology.
Post time: May-23-2024
