The service life of the cable has an important impact on the safety of the cable system. The service life of the cable mainly depends on the oxidation induction period of the sheath material. Although the effective use period of the ordinary cable is theoretically 20 years, the actual service life is far more than the actual service life. this. The cause of cable aging in life is that the insulation is reduced and the breakdown is caused. The insulation of the conductor cable is reduced, which is the fuse that causes the cable to be physically damaged and the life is shortened.。
What are the factors that affect cable life?
External force damage: During the transportation and cable construction process, there are not many cases of damage to the skin or core due to improper operation. Subtle mechanical damage may be difficult to detect during construction, but it has buried a huge hidden danger for later use. The longer the time, The more serious the damage, the much shorter the effective life of the cable.
Insulation is damp: There are two cases of moisture in the insulation layer. One is caused by moisture intrusion during cable production and storage, and one occurs during cable use. The cable joints laid in the direct buried or drained pipes are the most vulnerable parts. When the joints are made in a humid environment and the joints are not made properly, the water vapor will enter the cables. After a long time, the water vapor will gradually damage the insulation performance of the cables, resulting in malfunction.
Chemical corrosion: Direct embedding in areas with acid-alkaline chemicals will cause cable armor and protective layer to be corroded. The protective layer of chemical corrosion will be ineffective for a long time, and the insulation will be reduced, resulting in frequent failures.
Long-term overload operation: under the influence of current thermal effect, the load current passes through the cable, causing the core to heat up. At the same time, under the effect of the charge skin effect and the eddy current loss and the dielectric loss of the steel stern, more heat is generated. Accelerated cable temperature rises sharply. In this case, the cable is overloaded for a long period of time, which will accelerate the insulation aging and cause the insulation to be broken down.
Cable connector failure: The connector of the cable is a relatively weak part of the cable, and there are not many cases where the cable connector fails due to improper construction. Make the cable joints should be tightly pressed and fully heated, otherwise the cable head insulation will be reduced and the cable life will be shortened.