Pay attention to several major factors in the construction of high-voltage cross-linked cables !
- Release date: 2018/5/24 Views: 3
- The high-voltage cross-linked cable is a bridge between the power supply equipment and the power-consuming equipment, and functions as a power transmission device, and is widely used, but faults often occur. There are many reasons for the failure of high-voltage cables, and construction quality is one of them.
There are many examples of high-voltage cross-linked cable system failures due to construction quality. The main reasons are as follows:
1. The site conditions are relatively poor. The environment and process requirements of the cables and joints are high in the factory, and the temperature, humidity and dust on the construction site are not well controlled.
2. During the construction of the cable, it is inevitable that small scratches will be left on the insulating surface. The semi-conductive particles and the sand on the abrasive cloth may also be embedded in the insulation. In addition, the joint will be inhaled due to the insulation being exposed to the air during the construction process. These all leave hidden dangers for long-term safe operation.
3. The construction and installation are not strictly in accordance with the process construction, or the process regulations do not take into account possible problems.
4. Completion acceptance adopts the DC withstand voltage test to cause the reverse electric field in the joint to cause insulation damage.
5, due to poor sealing treatment. The intermediate joint must be made of metal copper casing, plus the sealing structure of PE or PVC insulation coating, which ensures the tightness of the seal during on-site construction, so as to effectively ensure the joint has good sealing and waterproof performance.
6, improper cable laying method, illegal construction. When the wire is unwound, the cable reel is not placed on the rotatable turntable, but the cable is placed on the ground from the reel and pulled straight, causing the cable to be twisted and damage the cable. Severely, the cable core is pulled out, that is, the three-phase cable core is not in the same plane, and there is an in and out.
There are many other factors, such as design reasons.
The cable is crushed due to thermal expansion of the cable to cause breakdown. When the design is selected, the cable section has a small load and the core temperature rises during operation. The cable is heated and expanded to reduce the insulation. The drawing does not indicate the special location of the laying method. For example, when laying, the cable top on the corner of the bracket is close to the right angle. At this point, the long-term and heavy-load operation of the cable has a large amount of creeping force, which causes the outer sheath of the cable or the metal sheath to be crushed at the elevation or right angle of the bracket, and the insulation of the cable is broken to cause the cable insulation to break down.
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