NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
Common problems of cable faults found in cable fault detection: Damage during installation: The cable is accidentally damaged during installation, the mechanical traction is too large, the cable is too tight, or the cable is over-bent to damage the cable; External force direct damage: After installation, urban construction Common problems of cable faults detected in electrical cable fault detection: Damage during installation: Inadvertent damage to the cable during installation, excessive mechanical traction, excessive cable tension, or excessive cable bending damages the cable; External force direct damage: After installation, Urban construction is carried out in the cable path or near the cable, so the external force directly damages the cable: damage caused by external force: the vibration or shock load of the moving vehicle can cause the lead (aluminum) packaging of the underground cable to rupture; damage caused by natural phenomena: such as intermediate joints or Expansion of insulating rubber of the terminal head, expansion of the outer casing or cable jacket; scratches of the cable jacket connected to the nozzle or bracket due to the natural travel of the cable; excessive tension caused by settlement of land, and intermediate joints or conductors destroyed. Cable Failure Detection Insulation causes failure when wet. Cable fault detection The main reasons for cables getting wet are: the joint box or junction box structure is not sealed or poorly installed, resulting in water leakage; poor cable manufacturing, small holes or cracks in the metal sheath; metal sheath pierced or corroded by foreign objects; cable insulation Air gaps within the medium are released by the electric field to reduce insulation.
When the insulating medium is ionized, chemical products such as ozone and nitric acid are produced in the air gap to corrode the insulator; moisture in the insulating material causes the insulating fibers to hydrolyze, resulting in reduced insulation. Overheating can cause the insulation to deteriorate. The internal air gap of the cable creates electrical separation, resulting in localized overheating and carbonization of the cable fault detection insulator.
Cable overloading is a very important factor in cable overheating. Cables installed in densely populated areas, cable trenches and cable tunnels, such as cables with poor ventilation, cables in dry ducts, and cables close to heat pipes, can be accelerated and damaged by overheating.
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