power cable Operation and maintenance of
The operation of power cable line is one of the important links in power production. The safety of cable line operation is related to the safety of enterprise production and the safety of people's life and property. Based on years of work experience, the author briefly introduces the relevant problems in the operation and maintenance of power cable.
Characteristics of cable line
Cable line refers to the line using cable to transmit electric energy. It is mainly composed of cable body, cable intermediate joint, electrical line end, etc., and also includes corresponding civil engineering facilities, such as cable trench, pipe rack, shaft, tunnel, etc. Generally, it is laid underground, or overhead or underwater. Compared with overhead lines, cable lines have the following main advantages:
① It shall not be disturbed by natural meteorological conditions (such as thunder, rain, smoke, pollution, etc.),
② Not affected by the growth of trees along the line;
③ It is conducive to beautifying the urban environment;
④ It does not occupy the ground corridor, and the same underground passage can accommodate multiple circuits;
⑤ It is conducive to preventing electric shock and safe use of electricity;
⑥ Maintenance costs are small. However, there are also the following shortcomings;
⑦ For the same conductor cross-section, the transmission current is smaller than that of overhead line:
⑧ The investment and construction cost is multiplied and increases with the increase of voltage;
⑨ The fault repair time is also long.
At present, the medium voltage distribution lines shall adopt wire lines under the following conditions:
① According to the urban planning, prosperous areas, important sections, main roads, high-rise building areas and those with special requirements for the city's appearance and environment;
② The overhead line corridor is difficult to solve;
③ Users with high power supply reliability or important load;
④ Key scenic spots;
⑤ Important power supply areas of major cities vulnerable to tropical storms in coastal areas;
⑥ The need for grid structure or operation safety;
⑦ The downtown area with high load density.
