The cable fault tester under UHV power can help many power workers conduct various power tests more conveniently.

Except for power transmission cables on utility poles, almost all cables currently in use are insulated. The insulation resistance level or degree of a cable depends on its design purpose. One of the most important reasons for cable insulation, besides saving energy loss or dissipating it to the surrounding area, is to avoid the danger of electric shock.

Electricity is very dangerous. The first touch may be the last touch, it will never give any chance. Slight contact with cables carrying current may lead to fatal accidents. Our body parts conduct electricity. When our body comes into contact with a current carrying conductor, the current tends to flow from the conductor to our body. Our body is a partial conductor and cannot conduct electrical current. When our body can contain too much electrical current, killing people becomes a problem.

To avoid such accidents at home, cables must be insulated. Insulation prevents current leakage and from reaching us, thus preventing us from getting electrocuted.

What is an insulator?

An insulator is a material or substance that does not conduct heat or conducts heat. Insulators do not conduct heat or electricity because they do not have freely moving electrons. It is said that conductors are insulated when covered with insulation materials such as PVC. This process is called insulation. The insulation around the conductor can prevent electrical energy and signals from escaping to the surrounding area.

The Effect of Temperature on Insulation Materials

The increase in temperature will increase the resistance of the conductor, while the resistance will decrease with the increase in temperature of the semiconductor and insulator. The increase in temperature can make semiconductors become good conductors and insulators become semiconductors.

Insulation resistance of cables

The cable conductor has insulation of appropriate thickness to avoid current leakage. The thickness of any cable depends on its design purpose. The current leakage path in this type of cable is radial. The resistance or reactive force of insulation on current is also radial along its entire length.

For a single core cable conductor 1 with a radius of r, an internal sheath radius of r2, a length rise, and an insulation material resistivity ρ, the circumference of the conductor is 2 π R. The thickness of the insulation layer will be given in dr units.

Plugin=ρ dr/2 π R liter

After integration, we will:

Plug in=ρ/2 π liters [Private room - [R 2/R 2]

The plugin is inversely proportional to 1/liter, which violates R=ρ liter. Among them, ρ (rho) is a constant called resistivity.

Some cables have multiple insulation layers and multiple cores. The main line is located in the center and serves as the main conductor. The other core is used for grounding and preventing electromagnetic waves and radiation from escaping from the cable. It serves as a shield. This type of cable is a coaxial cable.

Coaxial cables use inner conductors to transmit conductive signals (the inner or main conductor can be any good conductor, but copper is the most preferred because of its low resistivity and can also be electroplated), mainly contained in PVC shells. Before the outer PVC shell, there are two or more other insulators with aluminum foil or copper stranded wire between them. The outermost PVC shell protects the cable from external environmental influences. When voltage passes through the inner conductor, the shield or shell has almost no or no voltage passing through it.

The advantage of coaxial design is that the electric and magnetic fields are confined within the dielectric, shielding the outside with almost no leakage. Due to the insulation level in the cable, it can prevent external electromagnetic fields and radiation from entering, thus avoiding interference. Due to the smaller resistance of conductors with large diameters, there will be less leakage of electromagnetic fields. The same applies to cables with more insulation. Due to the fact that weaker signals are easily disrupted by interference, cables with more insulation layers are always the ideal choice for transmitting such signals.