Compared with cable lines, high-voltage overhead power lines refer to using pole towers as supports, and using specific insulators to fix and mount metal wires with good electrical conductivity to isolate them from the ground and maintain sufficient phase distance and ground contact. Distance, electrical equipment dedicated to the transmission and deployment of electric power to a given area. According to different voltage levels and functions, high voltage circuits can be divided into:
1. High voltage distribution lines. The current voltage level is 6~35Kv
2. High voltage transmission lines. The rated voltage is 35~220Kv
3. EHV transmission lines. The rated voltage is 330~1000Kv
4. UHV transmission lines. The rated voltage is above 1000KV.
The advantages of high voltage lines are:
1. The structure of the conductive material is simple, easy to manufacture and supply, easy to construct, fast in construction, convenient in operation and maintenance, good in heat dissipation performance of the line, and large in transmission capacity.
2. Low construction investment costs, low technical requirements and easy to meet. Under the condition of the same transmission capacity, the investment of high-voltage lines is only 8%~20% of that of cable lines.
3. It is easy to overhaul when the high-voltage line fails, and the method of live work can be used for overhaul, which can reduce the number of power outages and increase the guarantee of continuous power supply.
High voltage lines also have limitations. Since all equipment is exposed on the ground, it will inevitably be affected by various natural climates, which is the main issue considered in the design, construction and operation and maintenance of high-voltage lines.
