Analysis of the factors causing the insulation performance of silicone rubber cable to decline

- May 18, 2020-

Silicone rubber cable has the characteristics of cold resistance, softness, wear resistance, oil resistance, etc. It is suitable for driving with AC rated voltage of 0.6 / 1KV and below, and has special requirements for cold resistance and oil resistance. The split-phase shielded nitrile flat cable is suitable for power supply of the inverter , Wear-resistant anti-corrosion cable is suitable for electrical connection between mobile electrical equipment in harsh environments such as power generation, metallurgy, chemical industry, port, etc., mobile wear-resistant anti-corrosion, tensile resistance, high and low temperature, acid and alkali resistance is good.
Because of its structure and appearance, it is used in various fields of industry, mainly playing the role of power transmission. Most of the causes of flat cable failures are breakdown due to reduced insulation. There are many factors that lead to the reduction of insulation. According to the actual operating experience, the following conditions can be summarized.

5c949b8c1ab3f     (1) Chemical corrosion: The silicone rubber cable is buried directly in the area with acid and alkali effects, which often causes the outer protective layer to be corroded. The protective layer is subjected to chemical corrosion or electrolytic corrosion for a long time, which causes the protective layer to fail and the insulation performance is reduced. error occured.
     (2) Moisture insulation: This kind of situation is also very common, generally occurs at flat cable joints in direct buried or drain pipes. For example: unsatisfactory production of silicone rubber high-temperature cable joints and making silicone rubber high-temperature cable joints under humid climate conditions will cause the joints to enter water or mix with water vapor, which will form water branches under the action of an electric field for a long time and gradually damage the insulation of the cable Strength.
     (3) External force damage: According to the industry operation analysis in recent years, many cable faults are now caused by mechanical damage. For example: the construction of silicone rubber high-temperature cables is not standard construction, which is easy to cause mechanical damage. Sometimes if the damage is not serious, it will take months or even years to cause the breakdown of the damaged part to form a failure, and sometimes serious damage may cause a short-circuit failure in a short time, which directly affects the operation of the equipment and the power unit.
       The cable connector is faulty. Silicone rubber high-temperature cable joints are the weakest link in the cable circuit, and cable joint failures caused by direct errors (poor construction) of personnel often occur. In the process of making cable joints, if the joints are not tightly pressed or the heating is insufficient, the insulation performance of the cable head will be reduced, which will cause an accident.
        Long-term overload operation. Overload operation, due to the thermal effect of the current, the conductor will heat when the load current passes through the silicone rubber cable. At the same time, the skin effect of the charge, the eddy current loss of the steel armor, and the dielectric loss will also produce additional heat, which will increase the temperature of the cable. . During long-term overload operation, excessively high temperature will accelerate the aging of the insulation, and even the insulation will be broken down. In the hot summer, the temperature rise of the cable often leads to the breakdown of the cable insulation first, so in the summer, there are many cable failures.
And other reasons such as normal aging of the flat cable itself or natural disasters. Environment and temperature. The external environment and heat source of the flat cable will also cause the flat cable to have an excessively high temperature and insulation breakdown.