What are the factors causing the failure of underground distribution cable

Sometimes the underground distribution cable will have some faults in the working process, resulting in some problems. Therefore, we should understand the causes of the faults, so as to prevent and prevent the faults. Let's have a look.

• What are the factors causing the failure of underground distribution cable

  
  

  
  

1. Overload operation: long-term overload operation will increase the cable temperature and aging the insulation, so as to break down the insulation and reduce the construction quality.

2. The electrical aspects include: the construction process of underground cable head can not meet the requirements, the sealing performance of cable head is poor, the moisture invades into the cable, and the cable insulation performance decreases; Protective measures were not taken during cable laying, the protective layer was damaged and the insulation was reduced.

3. Civil Engineering: the drainage of the well pipe trench is not smooth, and the cable is soaked in water for a long time, damaging the insulation strength; The shaft is too small, the bending radius of the cable is not enough, and it will be damaged by extrusion external force for a long time. It is mainly due to mechanical barbaric construction and cable cutting in municipal construction.

4. Corrosion: the protective layer is subject to chemical corrosion or cable corrosion for a long time, resulting in the failure of the protective layer and the reduction of insulation.

5. The quality of the underground cable itself or the accessories of the cable head is poor, the sealing of the cable head is poor, the insulation glue is dissolved and cracked, resulting in the resonance phenomenon of line disconnection fault, which makes the line phase capacitance and ground capacitance form a resonance circuit with the excitation inductance of the distribution transformer, so as to stimulate ferromagnetic resonance.