The cable is the bridge between the power supply equipment and the electrical equipment, and plays the role of transmitting electrical energy. Because of its wide range of applications, faults often occur. The following brief analysis of the causes of the common problems of high-voltage cables and their classification according to the causes of faults can be broadly classified into the following categories: manufacturer's manufacturing reasons, construction quality reasons, and design unit design reasons. .
First, manufacturers for manufacturing reasons <br> <br> factory manufacturing reasons occurred according to different parts of the body is divided into cable reasons, the reason connector cable, grounding cable system three reasons.
<br> <br> manufacturing reasons the cable body in the cable manufacturing process is generally prone to problems insulating eccentric uneven thickness of the insulation shield, impurity, external shielding insulating protrusion, unevenness degree of crosslinking, wet cables, cable Poor metal jacket seals, etc. In some cases, serious failures may occur during or shortly after completion of the test, most of which are in the form of defects in the cable system, causing serious hidden troubles in the long-term safe operation of the cable.
Cable connector for manufacturing reasons <br> <br> with high voltage cable connector before wrapping type, molded type, type and other types of molding, making the workload required site and because of limitations of the production process and the field conditions, the insulating Inevitably, there are air gaps and impurities between the belt layers, so problems are likely to occur. The types commonly used in China are assembly and prefabrication.
The cable joints are divided into cable end connectors and cable intermediate joints. No matter what the joint type is, the cable joint failure usually occurs at the fracture of the cable insulation shield because it is the location where the electrical stress is concentrated and the cause of the cable joint failure due to manufacturing reasons is stress. Cone body manufacturing defects, insulation filler problems, oil leaking seals and other reasons.
Cable Grounding System <br><br><br><br><br><br><br><br><br> Cable grounding system includes cable grounding box, cable grounding protection box (with cover protector), cable cross-interconnect box, cover protector and other parts. The general problem that is easy to occur is mainly because the poor sealing of the box body leads to multi-point grounding, causing the metal sheath induction current to be too large. In addition, the selection of protective layer protector parameters is unreasonable or the quality of the zinc oxide crystal is unstable, and it is easy to cause damage to the protective layer protector.
Second, the reason for the construction quality of construction quality because <br> <br> lead to instances of high-voltage cable system failure lot, mainly in the following areas: First, the relatively poor field conditions, cables and connectors at the factory manufacturing environment and process requirements They are all very high, and the temperature, humidity and dust on the construction site are not well controlled. Secondly, during the cable construction, it is inevitable that tiny 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, during the construction of the joint, the insulation is exposed to the air and the insulation is also inhaled. Moisture, these all leave hidden dangers for long-term safe operation. Third, the installation did not strictly follow the process of construction or process regulations did not take into account the possible problems. The fourth is that the DC voltage withstand test results in the formation of a back-EMF in the joint resulting in insulation failure. The fifth is due to poor sealing. The middle joint must adopt the sealed structure of metal copper shell plus PE or PVC insulation coating to ensure the solidity of the seal during construction on site, which effectively ensures the sealing and waterproof performance of the joint.
Third, the cable design reasons <br> <br> cable due to thermal expansion caused Jishang cause breakdown. When the cross-linking cable load is high, the temperature of the core is increased, the cable is thermally expanded, and the cable is turned on the bracket elevation at the turning point in the tunnel. The long-term heavy-duty operation of the cable has a large amount of peristaltic force, which causes the bracket facade to crush the outer jacket of the cable. , Metal sheathing, intrusion into the cable insulation leads to cable breakdown.
First, manufacturers for manufacturing reasons <br> <br> factory manufacturing reasons occurred according to different parts of the body is divided into cable reasons, the reason connector cable, grounding cable system three reasons.
<br> <br> manufacturing reasons the cable body in the cable manufacturing process is generally prone to problems insulating eccentric uneven thickness of the insulation shield, impurity, external shielding insulating protrusion, unevenness degree of crosslinking, wet cables, cable Poor metal jacket seals, etc. In some cases, serious failures may occur during or shortly after completion of the test, most of which are in the form of defects in the cable system, causing serious hidden troubles in the long-term safe operation of the cable.
Cable connector for manufacturing reasons <br> <br> with high voltage cable connector before wrapping type, molded type, type and other types of molding, making the workload required site and because of limitations of the production process and the field conditions, the insulating Inevitably, there are air gaps and impurities between the belt layers, so problems are likely to occur. The types commonly used in China are assembly and prefabrication.
The cable joints are divided into cable end connectors and cable intermediate joints. No matter what the joint type is, the cable joint failure usually occurs at the fracture of the cable insulation shield because it is the location where the electrical stress is concentrated and the cause of the cable joint failure due to manufacturing reasons is stress. Cone body manufacturing defects, insulation filler problems, oil leaking seals and other reasons.
Cable Grounding System <br><br><br><br><br><br><br><br><br> Cable grounding system includes cable grounding box, cable grounding protection box (with cover protector), cable cross-interconnect box, cover protector and other parts. The general problem that is easy to occur is mainly because the poor sealing of the box body leads to multi-point grounding, causing the metal sheath induction current to be too large. In addition, the selection of protective layer protector parameters is unreasonable or the quality of the zinc oxide crystal is unstable, and it is easy to cause damage to the protective layer protector.
Second, the reason for the construction quality of construction quality because <br> <br> lead to instances of high-voltage cable system failure lot, mainly in the following areas: First, the relatively poor field conditions, cables and connectors at the factory manufacturing environment and process requirements They are all very high, and the temperature, humidity and dust on the construction site are not well controlled. Secondly, during the cable construction, it is inevitable that tiny 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, during the construction of the joint, the insulation is exposed to the air and the insulation is also inhaled. Moisture, these all leave hidden dangers for long-term safe operation. Third, the installation did not strictly follow the process of construction or process regulations did not take into account the possible problems. The fourth is that the DC voltage withstand test results in the formation of a back-EMF in the joint resulting in insulation failure. The fifth is due to poor sealing. The middle joint must adopt the sealed structure of metal copper shell plus PE or PVC insulation coating to ensure the solidity of the seal during construction on site, which effectively ensures the sealing and waterproof performance of the joint.
Third, the cable design reasons <br> <br> cable due to thermal expansion caused Jishang cause breakdown. When the cross-linking cable load is high, the temperature of the core is increased, the cable is thermally expanded, and the cable is turned on the bracket elevation at the turning point in the tunnel. The long-term heavy-duty operation of the cable has a large amount of peristaltic force, which causes the bracket facade to crush the outer jacket of the cable. , Metal sheathing, intrusion into the cable insulation leads to cable breakdown.
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