Industry News

Problems caused by poor contact of low voltage cable

2022-03-31
With the development of the industrial era, the dependence on electric energy is becoming more and more, in order to ensure the electricity demand of all walks of life and regions, the laying length of the wire has become huge, and the potential safety hazard has gradually become the object of attention, and now the harm caused by cable failure is also more and more, In past experience, we know that low-voltage cable accessories usually have heat and other characteristics such as poor joint contact, which will have some adverse effects. So what accidents may be caused by poor contact of low-voltage cable accessories?

1. Poor insulation of the cable joint of low-voltage cable accessories:
Refers to the cable joint due to poor processing or long-term operation caused by the insulation of the whole damp, deterioration and other defects, characterized by the cable head temperature is too high.

2. Poor local insulation of cable joints of low-voltage cable accessories:
Refers to the cable joint due to poor processing or long-term operation caused by local insulation damage, moisture, deterioration and other defects, which is characterized by high temperature in the local insulation area at the intersection of the cable joint.

3. Poor insulation of low-voltage cable accessories cable connector outlet bushing:
Refers to the defects of water inflow and dampness caused by poor sealing of the outlet bushing of cables above 35kV. The characteristic is that the temperature of the casing increases, and the temperature near the flange is higher.

4. Low-voltage cable accessories Overall cable heating:
It refers to the defect caused by cable insulation aging or over-load operation.

5. Poor contact of power capacitor of low-voltage cable accessories:
The judgment of shunt capacitors (series capacitors) shall be carried out according to relevant regulations. When the thermal image is abnormal or the same kind of relative temperature difference exceeds the standard, other test means should be used to determine the nature of defects and treatment suggestions.

6. Poor insulator contact of low-voltage cable accessories:
A. Porcelain insulator string:

a) The temperature distribution of normal insulator string corresponds to the voltage distribution, that is, it is asymmetrical saddle type, and the temperature difference between adjacent insulators is very small.

b) The thermal image characteristics of low-value insulators are that the temperature rise of steel caps is higher, while that of zero-value insulators is that the temperature rise of steel caps is lower, and that of dirty insulators is that the temperature rise of porcelain plates is higher.

B. Support insulators:
Normal support insulators have slight heat near the conductor, while abnormal insulators show significant heat in whole or part.

At present, in the cable construction process, we work mainly adopts high voltage cable to cable at the bottom of the method for moving, to maintain the balance of the cable in the electric field distribution area, in order to ensure the stable operation of the cable, so as to carry on the reasonable release voltage stability, improve power quality, for people to use. HUAYI CABLE ACCESSORIES Co.,Ltd. reminds you to strictly follow the instructions when installing cable accessories.