The reasons for the failure of power cables are the cumulative result of many factors and time. In order to prolong the life of the cable, it is necessary to detect the cause of the failure faster, so it is necessary to study the common causes of cable failure. Here, the cable flaw detector manufacturer will The reason for the failure of the power cable is the cumulative result of many factors and time.
In order to prolong the life of the cable, it is necessary to detect the cause of the failure faster, so it is necessary to study the common causes of cable failure. Here, cable flaw detector manufacturers will introduce the causes of common cable faults to help you make better use of cables. 1. Mechanical damage Mechanical damage is mainly divided into three types: one is the damage caused by direct external force, such as frequent digging, handling, overweight, etc. during urban construction, which may cause accidental accident of power cables; The third is the damage of natural external forces, such as soil subsidence, landslides, etc., which cause the breakage of the cable joint or body, or the cable due to the low temperature in winter. or its accessories freeze and crack, etc.
2. Insulation dampness Insulation dampness is the second largest factor of power cable failure. When manufacturing cables, if the structure of the installation box or terminal box is not qualified or the sheath is damaged, it may cause the insulation to get wet, thereby reducing the insulation performance and causing failure. 3. Overvoltage The insulation layer equipment of the cable has a certain upper limit of voltage withstand.
If operating with atmospheric overvoltage and internal overvoltage conditions, its limits will be exceeded and the insulation will be broken down. Many terminal head failures in outdoor environments are caused by overvoltage, which can magnify certain defects in the cable itself, resulting in accidents. 4. The manufacturers of overheating cable flaw detectors pointed out that there are many reasons for overheating. The internal reasons are mainly the local overheating caused by the free air gap inside the cable insulation, thus carbonizing the insulation; the external reasons are mainly the temperature rise caused by long-term overload operation. Especially in the sweltering heat, the cables in the cable trenches and tunnels are poorly ventilated or in the drying pipe, and the insulation performance is easily decelerated and damaged due to their high temperature.
5. Corrosion of the sheath Under the action of electrolysis and chemistry, the lead package outside the cable is extremely susceptible to corrosion. The corrosion of the protective layer can be caused by different factors and degrees, so that the surface of the lead package shows red, yellow and orange compounds or sponge-like pores. 6. Design and production process problems Waterproofing of intermediate joints and terminal joints, unreasonable electric field design, poor technicians or failure to lay cables according to technical requirements often cause cable failures.
7. Material defects The first is cable defects. Not only can lead and aluminum cladding leave defects, but improper wrapping insulation can also cause defects such as folds, cracks, overlaps, or gaps in paper insulation. Second, there are problems in the manufacture of cable accessories, such as sand holes in iron castings, low mechanical strength of porcelain parts, other parts that do not meet specifications, and incomplete sealing during assembly.
The third is insulation material defects. This is mainly reflected in the inadequacy of daily maintenance and management, which makes the insulation medium in the middle section of the cable and the joints at both ends age, pollute and get wet, which reduces the quality of the joints. I believe that after reading the above introduction of cable flaw detector manufacturers, you should have an understanding of the common causes of cable faults.
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