Author: Noyafa–CCTV Tester
Reasons for power cable failures: There are many reasons for cable failures. Now the common main reasons are summarized as follows: 1. Mechanical damage: Many faults are caused by careless mechanical damage during cable installation or after installation. Reasons for the failure of power cables close to the cable: There are many reasons for the failure of the cable. Now the common main reasons are summarized as follows: 1. Mechanical damage: Many failures are caused by mechanical damage or accidental cable installation. Mechanical damage caused by construction close to the cable after installation. If the damage is minor, it can take months or even years for the damaged area to develop insulation failure. Cause the damaged part to completely collapse and cause a failure.
2. Electrical corrosion of the cable sheath: If the power cable is buried under the ground with a strong electric field (such as large-scale traffic, near the electric locomotive track), the phenomenon of lead-pack corrosion of the cable sheath often occurs, resulting in moisture intrusion and insulation damage. 3. Chemical corrosion: Cables buried in areas with acid and alkali operations or near gas stations with benzene vapor often cause large areas and long-distance corrosion of cable armor and lead cladding. 4. Ground subsidence: This phenomenon often occurs when the cable passes through roads, railways and tall buildings. Due to the subsidence of the ground, the cable is subjected to vertical force and deformation, resulting in the rupture or even breakage of the cable armor, lead pack, and various types. failure.
5. Loss of cable insulation: When the cable is laid, the trench is uneven, or the outdoor head is on the pole. Due to the fluctuation of the cable and the difference in height, the insulating oil of the cable in the high place flows to the low place, which makes the insulation of the cable in the high place worse. A fall causes a malfunction to occur. 6. Long-term overload operation: Due to overload operation, the temperature of the cable will increase accordingly, especially in hot summer, the temperature rise of the cable often causes the weak point of the cable and the butt joint to be broken down first. This is the reason for the high rate of cable failures in summer.
7. Vibration rupture: The cable running under the railway track breaks due to the elastic fatigue of the cable sheath due to the violent vibration, resulting in a failure. 8. Poor craftsmanship, poor joints and cables that are not laid according to technical requirements are often important reasons for cable failures. 9. Make joints under humid climate conditions, so that water vapor is mixed into the joint package, which often causes flashover failures after a period of time.
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