Share the role and principle of cable shielding grounding

　　The shielding layer is a wire with a metal braid shell specially used to reduce the influence of the external electromagnetic field on the power supply or communication lines. This kind of shielded wire also has the function of preventing electromagnetic energy from radiating outwards to a certain extent. In order to prevent interference signals from entering the inner conductor interference and reduce the loss of the transmission signal, the shielding layer of the cable needs to be grounded. Next, Pearl River Cable will explain the role and principle of the shielding layer grounding in detail!

　　It is difficult to ensure that there is no potential difference between the grounding points at both ends. If there is a potential difference, there will be a weak current, so that the shielding layer actually becomes a grounding wire; while the shielding wire grounded at both ends works in a work site with severe high-frequency interference, which will be shielded The line capacitance formed between the layer and the internal signal line is coupled to the signal loop, which will seriously affect the signal misjudgment. I have seen various speed regulators and the instructions clearly stated that the signal wire and shielding wire must be grounded at a single end and the grounding end should be on the side of the controller.

　　The shielding layer is usually grounded when one end of the cable shielding layer is connected to the equipotential grounding bar, and the other end is not connected; if both ends are grounded, a potential difference will be formed between the two grounding points, which will interfere with the signal transmission. How should it be grounded? There are two main types of so-called grounding:

　　1. To ground the ground, first ensure the reliability of the total grounding body, the grounding resistance should be small, and at the same time, it should be as far away as possible from the building's lightning protection grounding and high-distribution grounding system. Ensure the equipotentiality of each ground point. It is used for the grounding of the equipment shell and the outer layer of the double shield. If it is determined that the grounding points are reliable and absolutely equipotential, then multiple grounding points are definitely good.

　　2. Technical grounding (signal ground), mainly used for the second layer of shielding grounding to reduce signal distortion, because the signal ground is actually the zero potential ground of the working power supply of the electronic printed board, which is the zero point of the system signal power supply. The two layers of shielding should be mutually insulated and isolated shielding! If they are not insulated from each other, they should still be regarded as single-layer shielding!

　　The grounding of both ends of the outermost shielding layer induces current due to the introduced potential difference, thus generating magnetic flux that reduces the intensity of the source magnetic field, thereby basically canceling out the voltage induced when there is no outer shielding layer; while the innermost shielding layer is grounded at one end , Since there is no potential difference, it is only used for general anti-static induction.

　　When a shielded cable is used, its shielding layer should be equipotentially connected at least at both ends. When the system requires equipotential connection only at one end, two layers of shielding should be used, and the outer shielding should be handled in accordance with the aforementioned requirements. To prevent electrostatic interference, it must be grounded at a single point, whether it is a one-layer or two-layer shield, because the electrostatic discharge speed of a single-point grounding is the fastest.

　　Just as the cross-linked polyethylene insulated power cable has good thermo-mechanical properties, excellent electrical and chemical corrosion resistance, it also has the advantages of simple structure, light weight, and no drop restriction in laying. At present, it is widely used in urban power grids, mines and chemical plants. The cable insulation adopts cross-linked polyethylene, which uses chemical methods to convert linear molecular polyethylene into a three-dimensional network structure of cross-linked polyethylene, thereby greatly improving the mechanical properties of polyethylene and maintaining excellent electrical properties. Zhujiang Cable has introduced advanced wire and cable manufacturing technology, production equipment and testing equipment. It has imported wire-drawing equipment, imported fully automated cradle packing equipment, advanced granulation production equipment, automated granulation pipeline transportation systems, etc., and also introduced industry Advanced cross-linked wire and cable production line, medium and low voltage wire and cable production line, etc.; and all products produced are guaranteed to be qualified for national sampling.

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