Analysis of common faults of wire and cable

Update:06 Sep 2017
Summary:

   Wire and cable common faults are mechanical damage, […]

   Wire and cable common faults are mechanical damage, insulation damage, over voltage, cable overheating fault. Here to specifically talk about the cause of cable failure.
     
1, external damage
     
Mostly due to cable laying installation is not standardized construction, likely to cause mechanical damage, in the direct laying of cables on the construction of high civil construction caused by cable damage and so on. Sometimes damage will not immediately problems, there may be months or even years will lead to damage to the formation of parts of the failure, serious damage may occur short-circuit failure affect the safety of production units.
     
2, chemical corrosion
     
Cables are buried directly in areas where acid and alkali act, causing the armor of the cable, the lead skin or the outer protective layer to be corroded. Resulting in failure of the protective layer, insulation reduced.
     
3, quality problems
     
The cable itself or the cable head attachment quality is poor, the cable head sealing poor insulation glue dissolved, cracking, resulting in the phenomenon of the phenomenon of line disconnection caused by the line and the capacitance and capacitance and distribution transformer excitation inductance constitute a resonant circuit, Magnetic resonance.
     
4 environment and temperature
    
The ambient environment in which the cable is located and the heat source in the installation environment are also subject to high cable temperatures, insulation breakdown, and even fire.
     
5 break caused by fault
      
Broken circuit resonance In severe cases, high frequency and fundamental frequency resonance superposition, can make the overvoltage amplitude to phase voltage [P] 2.5 times, may lead to system neutral displacement, winding and wire over voltage, severe So that the insulation flashover, arrester explosion, electrical equipment damage.In some cases, the load transformer phase sequence may be reversed, it may also pass the voltage to the low side of the transformer, causing harm.

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