What are the hazards caused by cable aging?
What are the hazards caused by cable aging?
The operation of power cables is one of the important links in our daily life, work, and production.
The safety or not of cable line operation is related to the safety production of enterprises and the safety of people’s life and property.
Due to long time use, power cables will also have a certain loss, the phenomenon of aging.
So what do the reasons for the aging of the wire and cable occur?
What harm will there be after the aging of the cable? The next Pearl River cable to explain the causes and hazards of aging wire and cable it.
The Causes of Aging of Wire and Cable
1 External Force Damage
From the analysis of the operation in recent years, many cable failures are now caused by mechanical damage.
For example cable laying and installation of non-standard construction, easy to cause mechanical damage.
In the direct buried cable on civil construction is also very easy to run the cable damage.
2 Insulation Moisture
Generally in the XLPE or PVC insulated cable, this situation is also very common, generally occurring in the direct burial or cable joints in the row of pipes.
For example, the cable joints are not qualified to make or do joints in humid climatic conditions, will make the joints into water or mixed with water vapor, a long time in the electric field will be formed under the action of the water tree branches.
Water tree refers to the water immersion in the insulation layer, in the electric field under the action of the formation of dendrites.
The generation of water trees will gradually damage the cable insulation strength and cause failure.
3 Chemical Corrosion
The cable is directly buried in the area with acid and alkali action, which often causes the cable armor, lead skin or outer sheath to be corroded.
The protective layer suffers chemical corrosion or electrolytic corrosion for a long time, resulting in the failure of the protective layer and the reduction of insulation, which will also lead to cable failure.
4 Long-Term Overload Operation
Due to the thermal effect of the current, the load current through the cable is bound to lead to conductor heating.
At the same time, the skin effect of the charge and the eddy current loss of the steel armor, and insulation dielectric loss will also generate additional heat, thus increasing the temperature of the cable.
In long-term overload operation, the high temperature will accelerate the aging of the insulation, and the insulation will be broken.
5 Cable Toint Failure
Cable joints are the weakest link in the cable line, and cable joint failures due to poor construction often occur.
Construction workers in the process of making cable joints often a failure.
If there is joint crimping is not tight, heating is not sufficient and other reasons, it will lead to lower insulation of the cable head, which will lead to accidents.
6 Environment and Temperature
The external environment and heat sources that the cable is exposed to can also cause high cable temperatures, insulation breakdown, and even explosive fires.
The hazards of aging cables
Wire aging will increase power consumption, and line aging, if the outer insulation sheath is broken will not only increase line consumption, increase electricity consumption, but also cause circuit fires, which need to be replaced in a timely manner.
Wires often have high temperatures that will accelerate aging, the temperature is too high and will ignite the outer insulation skin to start a fire.
In practice, there are many people who do not understand the common sense of the circuit in the interconnection of two wires, just two or three turns with wire cutters and not tightened, which leads to the contact surface of the two wires at the joint being very small.
According to the knowledge of physics, the smaller the cross-sectional area of the conductor, the greater the resistance, heat Q = I square Rt, the resistance has become larger and leads to increased heat generation.
Therefore, we must often carry out regular line safety inspections.
Wires, electrical equipment, etc. should be fully and thoroughly checked by professionals at least once a year.
In particular, the joint parts of the line with long service life found that the wire aging, broken, poor insulation, and other unsafe conditions, to promptly repair and replace, in order to ensure the safety of electricity.
Finally, remind everyone that the purchase of wire and cable must be recognized by a regular manufacturer, check the quality, and do not go to buy some unqualified wire because the price is cheap.
