The electric power plant is not used for people nearby, and it is also transferred to a far-reaching place to meet more needs. These electricity cannot be transferred directly through ordinary wires, but to transfer with high pressure transmission lines. Generally, the transmission voltage below 220 kV is called high voltage transmission, and the transmission voltage of 330 to 765 kV is called ultra-high voltage transmission, and the power transmission voltage above 1000 kV is called special high voltage transmission. When electrical delivery to the place where the electricity is used, the voltage is reduced to use.
High voltage transmission line is divided into cable transmission line and overhead transmission line.
Cable transmission line: Built the cable underground, no space, but construction and maintenance is inconvenient, mostly used in the city and cross the river line.
Overhead transmission line: The wire and ground wire is hung in the air using the transmission rod tower, and between wires and wires, wires and ground wires, wires and rods, between wires, and ground obstacles. Keep a certain safe distance to complete the transfer task.
Features and the existing problem
compared to the existing low pressure, pre-pressure transmission line, high voltage AC transmission line has the following features:
1) Safety Reliability requirements are high. Due to high conveying capacity of high voltage AC transmission lines, it is often important for the main power point and the energy transfer line of the power supply point in the grid in the grid. Once the safety accident has a great impact on the economic impact.
2) The structure parameters of the line are high. High voltage AC transmission line rod tower, insulator string long, number of insulators, large tonnage, not only repairing difficulties after collapse, not only the difficulty of repairing the spare parts, the preparation of spare parts is also very high.
3) High running parameters of the line. The rated voltage of the high voltage line is relatively high, so that the electric field intensity around the carrier is high.
4) Long line, the geographic environment is complex, and the high voltage lines often cross the high mountain canyon, the traffic is more difficult, and the maintenance work is large.
Power generates high quality transfer to the electrical ground, must rely on the transmission function of the grid. High voltage transmission lines responsible for power plants and substations, power transmission and distribution between substations and substations, called the artery of power. Due to the uneven distribution of resources and population in my country, there is more necessary to strengthen the construction of high-voltage transmission lines, and efficiently deliver electrical energy to the electricity area to complete the task of shoulder the power. High voltage transmission line design is the focus of high-pressure transmission line planning and preparation work, and the design of high-pressure transmission line design is significant. Electric power workers should increase the attention of the design of the pressure transmission line, familiar with the high-pressure transmission line tower structure design, Working in lightning protection design and definition loss, effectively improve the design quality of high-pressure transmission lines, enhance the development of electric power industry and progress. In the actual high-voltage transmission line design, power workers should do mechanical analysis, defaining, and thunder design, improve the practicality and functionality of high-pressure transmission line design through practical grassroots, and is the stability of high voltage transmission lines. Run the actual basic design work.