What is Concentric Conductor Cable?

 The improvement of the global economic level has led to the rapid development of the cable industry, and it also consumes a large number of irreplaceable resources. More and more new power cable products are generated. Concentric cable is one of them.

So, what is the concentric cable? What are its structural characteristics and how to put them into use? Let's let the ZMS cable take you to learn about it.

Structural Characteristics of Concentric Cables

Concentric cables are arranged into one-equation triangles. There are several copper conductors outside the insulation core to form a concentric conductor.

The sum of the concentric conductor section is greater than or equal to the required neutral cross-section of the cable.

Product Type

Concentric cables and cross-linked polyethylene insulation power cables and polyvinyl chloride insulation electric cables are only different in the design structure.

Power cables are different in design structures with cross-linked polyethylene insulation electric cables and polyvinyl chloride insulating power cables.

The model uses the suffix "T" to distinguish. For example, VV-T, YJV-T, YJLV22-T, etc.

Concentric Cable and Ordinary Cable

1 Ordinary cable structure

Cable conductor material is composed of pure copper or pure aluminum.

3.6/6KV's single-core and multi-core cable conductor is a completely twisted graphic pressure core, which can reduce the outer diameter of the cable. Conducts can also be made into a conductive core with vertical water resistance.

The rated voltage is 0.6/1kV, (3+1) core, dual-core cable. The neutral line and phase line are twisted together to form cables.

2 concentric cable structure

The cables with the same -core conductor structure should have a concentric conductor layer outside the inner lining layer of the multi-core cable. Single-core cables should be set directly outside the insulation layer or an appropriate lattice layer.

The Use of Concentric Cables

The use of concentric conductors in GB/T127061 has no provisions. However, in the British standard BS4553-1998, the concentric core layer can be used as a neutral and grounded conductor.

The German standard DIN57271-1983 stipulates that the NYCY type uses concentric layer conductors that can be used as neutral, grounding lines, or zero lines, and it can also be used as a shielding line.

Concentric Cable Ground Method

Good shielding integrity and good grounding are very important for shielding cables.

The shielding ground is to prevent electromagnetic interference from electromagnetic equipment, which affects its work, or shielding equipment from electromagnetic interference to other equipment.

There are Two Ways to Cover The Shielding Layer of The Power System Shielding Cable

1. End to ground

2. One end of the ground

The shielding layer of the power system with the shielding of the control cable is grounded at the same time at both ends of the switching station and the control room. It is an internationally available effective secondary circuit anti-electromagnetic interference measure.

If the shielding layer is only grounded at one end, it is likely to occur at a high transient voltage at the end of the shielding layer, which affects the ground.

The Advantages of Grounding at Both Ends of The Shielding Layer

When the control cable is surrounded by the magnetic flux generated by the instantaneous current of the bus, the shielding current of the cable is generated.

The magnetic flux generated by the shielding current will offset the effect of the magnetic flux generated by the instantaneous current generated by the bus on the cable core.

Suppose it is the ideal shield. The comprehensive effect of the two will cause the magnetic flux in the cable core that is surrounded by the shielding layer to zero, which forms an ideal Faraday cage.

This is also the same as the ideal transformer with a secondary short route, and the core of the core will be zero.

Of course, for various reasons, the shielding effect of the shielding cannot be completely ideal.

Therefore, under the action of the instantaneous current of the bus, the shielded iron core will still feel a certain voltage.

The Advantages of Concentric Cables

1. Compared with ordinary low-voltage cable structures, the diameter of the cable can be reduced and the input of cable materials can be reduced.

2. When transmitting power, it will not interfere with the surrounding electrical equipment. The effect of foreign electromagnetic interference on electrical equipment connected to the cable is also eliminated.

3. It can avoid the breakdown or damage caused by the voltage of the strong lightning electromagnetic effect, and improve the reliability of the cable running under bad conditions.

4. It has a low and uniform positive (reverse) order and zero-order impedance. It can increase the sensitivity of the end -end of the line.

Compared with ordinary cables in the same cable, the zero-order electrical resistance is much lower, which can improve the reliability of line protection.

5. Eliminate ground failures caused by one-phase insulation and breakdown.

Conditions For The Use Of Concentric Cables

1. The maximum long-term allowable working temperature of the wire.

- Phhel chloride insulation at 70 ° C

- Alinter -linked polyethylene insulation 90 ° C.

2. The maximum temperature of the conductor does not exceed the range of the cable short circuit.

-Chide Elephant Insulation Cable 160 ° C.

- Alinter linked polyethylene insulation cable 250 ℃.

3. The ambient temperature at the time of laying should not be lower than 0 ° C.

4. The allowable bending diameter of the cable is

- Fines core cable is not less than 40 times the outer diameter of the cable

- Setic core cables are not less than 30 times the outer diameter of the cable

5. Flame retardant and refractory cables meet the corresponding flame retardant and refractory capacity requirements.

Use Occasions and Domestic and Foreign Applications

Due to the unique structure of concentric conductor cables.

concentric conductors can not only be used as zero or ground lines but also have excellent shielding performance.

It can improve the anti-interference performance of ordinary low-voltage power cables and the hazards of interference to adjacent electrical or control lines.

Therefore, it can be widely used in power stations, power plants, high-rise buildings, tunnels, subways, computer rooms, and other places.

The research and application of concentric cables in foreign developed countries are relatively standardized.

Not only did it formulate a separate national standard, but also made a detailed explanation of the use of concentric cables. concentric cables are widely used abroad for low-voltage electrical lines.

Concentric cables with a rated voltage of 06/1kV have excellent advantages compared to the low-voltage cables of ordinary structures. The production of materials in production is small, the structure is stable, and the shielding performance is excellent. Below, it has very obvious practical significance.

When choosing a cable, some information can help you choose more accurately and faster. ZMS cable companies are committed to providing a variety of high-quality cables and have strict artificial qualification reviews for products. It is highly professional in terms of cable manufacturing, and its products are trustworthy.