RU194412U1 - Noise suppression cable - Google Patents

Abstract

The utility model relates to cable technology. The interference suppression cable contains a conductive core placed in a shielding noise suppression sheath of overlapping tapes of metastable rapidly cooled alloys, coated with an external insulating coating on top. In this case, the cable is equipped with an additional shielding noise-suppressing copper sheath in the form of a cable stocking, located under the outer insulating coating and covering the shielding noise-suppressing sheath of tapes of metastable rapidly cooled alloys, and a ring magnetic core located on the end of the cable and covering the shielding noise-suppressing sheath of metastable alloy tapes quickly . 3 ill.

Description

The utility model relates to cable technology, namely, to the designs of power electric cables with a shielding, which provides noise immunity of conductive conductors from electromagnetic and magnetic effects from the environment. The design of the power cable for single-phase and three-phase power lines and for the transmission and distribution of electrical energy in stationary electrical installations is considered.

Thus, a cable for signal transmission with a connector is known from US 2005133245, comprising a shielded cable having a plurality of insulated wires, a shielding layer and an insulating coating layer, said shielding layer and an insulating coating layer covering the periphery of said insulated wires. The connector is electrically and mechanically connected to at least one end of said shielded cable and has a shielding metal cover extending from a portion of the housing to the end of the cable and a closed magnetic core that is mounted on a separate part of said insulating coating layer at the end of said shielded cable. In said core, an insulating tape is wound around said shielding layer in a peripheral part of said core, and an end portion of said shielding layer is connected to said protective metal cover in a state in which said core is placed in said protective metal cover.

It is known to use in noise-protected cables as a shield of a winding or braid of tinned copper or copper wire (RU112489, RU77721).

It is also known to use a magnetic circuit at the end of the cable as an element for suppressing electromagnetic waves and reducing electromagnetic noise, the element for suppressing electromagnetic waves contains a restrictive element and an annular magnetic core that contains nanocrystalline magnetically soft material (US 2018247758).

FR 2793593 (abstract) describes a cable comprising a layer of a ferromagnetic alloy, and providing the required magnetic shielding. The low-frequency cable includes a number of coaxial layers. The cable comprises a conductive core including a bundle of wires surrounded by a first dielectric layer. Then it is surrounded by an additional layer consisting of a magneto-absorbing layer made of a ferromagnetic alloy with an amorphous or nanocrystalline structure. The second dielectric layer surrounds the magneto-absorbing layer, and it, in turn, is enclosed in a shielding braid. An external insulating shell surrounds the entire structure. The magnetic absorption layer comprises 80% +/- 10% of atoms selected from Co, Fe, Mn and Ni, and the rest is selected from B, Si.

Studies conducted over the years have unequivocally proven that magnetic fields are an unfavorable environmental factor that negatively affects the operation of electrical and magnetic devices, as well as the health and performance of people. One of the most common and difficult to control sources of excess magnetic background are cable routes of power sources of power supply. From the point of view of the effect of the electromagnetic field on technical means and, especially, on biological objects, it is magnetic fields that should be considered the most “harmful” due to their large penetrating power. To reduce the magnetic field that occurs during cable operation to values that satisfy the current regulatory documents, it is necessary to use a power cable with an electromagnetic shield.

As a prototype, the decision is made, described in RU 2444075, НВВ 9/02, publ. 02/27/2012, This patent describes a power cable containing a multilayer screen made of tapes of amorphous and / or nanocrystalline magnetically soft alloys based on iron and / or cobalt with an initial magnetic permeability of at least 10⋅10 ³ . The screen is made by winding such a tape around the cable with an overlap with an overlap of at least the thickness of the tape itself. Relative to each other, the tapes are fixed using a polymer dielectric film. To fix the screen, an external protective shell is superimposed on it. In addition, in the design of the screen to achieve the required level of shielding, a multilayer screen is used, in which layers of alloys with different magnetic properties alternate. The inner layers of the shielding material having a high saturation induction absorb the bulk of the excess magnetic field generated by the working power cable. The remaining part, which has a significantly lower intensity, is absorbed by the outer layers of the shielding material due to the high magnetic permeability.

The disadvantage of this solution is that in this power cable the problem of protection against inductive interference is solved, but the problem of protection against conducted interference, which for the most part is pulsed in nature, and from intrinsic noise caused by uneven transmission of voltage is not solved.

This useful model is aimed at achieving a technical result, which consists in increasing the noise immunity of the power cable by reducing the effect of inductive and conducted interference.

The specified technical result is achieved in that the noise-suppressing cable containing a conductive core placed in a shielding noise-suppressing sheath made of tapes of metastable rapidly cooled alloys, which are overlapped along the length of the core with an overlap of not less than the thickness of the tape, and the outside of the shielding is coated with an external insulating coating, equipped with an additional shielding noise-suppressing copper sheath in the form of a cable stocking, located under the external insulation Indoor and female shielding shell Interference ribbons metastable rapidly cooled alloys, and the magnetic core of annular shape, disposed at an end portion of the cable and a female shielding shell Interference ribbons metastable rapidly cooled alloys.

These tapes can be made of amorphous alloys and / or from nanocrystalline soft magnetic alloys. And the magnetic circuit can be made in the form of cast ferrite or from a wound tape from metastable rapidly cooled alloys. The magnetic core can be located in a clamping sleeve mounted on the end of the cable.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result.

The present utility model is illustrated by a specific example of execution, which, however, is not the only possible one, but clearly demonstrates the possibility of achieving the required technical result.

In FIG. 1 - power cable design with a demonstration of the layered structure of the windings;

FIG. 2 - general appearance of the power cable;

FIG. 3 is a longitudinal section of the cable in the area of the location of the coupling with the magnetic circuit.

According to this utility model, the design of an interference-protected power cable designed for use in single-phase and three-phase power lines is considered.

The interference-protected power cable (Fig. 1) contains a conductive core 1, which can be represented either as a single wire or as several wires 2, which are equipped with terminals 3 at the output, used for termination for subsequent connection, for example, to the consumer or to mounting elements of the distribution block.

The conductive core is placed in a shielding interference suppressing sheath 4 made of tapes of metastable rapidly cooled alloys (amorphous or nanocrystalline), which are overlapped along the length of the core with an overlap of no less than the thickness of the tape. Tapes are made of amorphous and nanocrystalline alloys based on cobalt, cobalt iron and nickel iron. The use of tapes made of metastable rapidly cooled alloys (amorphous or nanocrystalline) as an interference suppression screen provides high-quality interference suppression, mainly from the influence of a magnetic field. Due to the fact that the tapes are overlapped in such a sheath of the protective coating, the presence of magnetic "holes" is excluded. The layer of shielding material has a high saturation induction and absorbs a significant part of the excess magnetic field generated by a working power cable. The effectiveness of the use of such tapes of metastable rapidly cooled alloys (amorphous or nanocrystalline) as a shielding magnetic field of the shell is proved in the prototype. Moreover, the same shell also shields the magnetic field coming from the external environment.

When shielding a power cable due to the use of a tape sheath made of metastable rapidly cooled alloys, the magnetic field level decreases to 500%, which ensures compliance with the requirements of SanPiN 2.2.4.1191-03 "Electromagnetic fields in industrial conditions" and GN 2.1.8 / 2.2.4.2262-07 "Norms (maximum permissible levels) of magnetic fields with a frequency of 50 Hz in the premises of residential, public buildings and in residential areas."

A cable, as an electrical device, is exposed to interference from the external environment and is itself a source of interference, the main of which is electromagnetic radiation. To protect the cable from external electromagnetic radiation and to prevent the transmission of the same radiation from the conductive core to the external environment, an additional screening of the conductive core is used with a shielding noise-suppressing copper sheath 5 in the form of a cable stocking, which is located under the outer insulation coating 6 and covers the shielding noise-suppressing sheath 4 of tapes metastable rapidly cooled alloys. The properties of a copper shielding to protect conductive wires from electromagnetic, inductive, capacitive and other types of interference are widely known. This cladding provides protection against conducted interference and interference. So, a copper braid with an 85% cable coating can reduce interference, expressed, for example, in the form of noise, by 100 times.

Outside, the shielded core is covered with an external insulating coating 6 from a range of insulating materials allowed to be used for insulation of cable products.

Electromagnetic interference propagates not only in the radial direction from the vector of the conductive core, but also along this core. In this regard, it is necessary to limit the transmission of such longitudinally propagating interference to the end user, that is, to the cable lugs. To do this, a ring-shaped magnetic core 7 is installed on the cable, placed on the end of the cable and covering the shielding noise suppressing sheath 4 of tapes of metastable rapidly cooled alloys. To isolate this magnetic circuit, a clamping clutch is mounted at the end of the cable (Fig. 2 and 3), which consists of a fixed part 8 fixed to the end of the cable (through which the ends of the wires of the core) - the clutch housing and the movable part 9 - of a nut or cover, by turning which provide isolation of the magnetic circuit from the external environment. This clutch, in addition to the function of isolation from the external environment, also solves the problem of positioning the magnetic circuit and holding it at the end of the cable.

The magnetic core can be made in the form of cast ferrite or from a wound tape from metastable rapidly cooled alloys. A magnetic core in the form of molten ferrite is a passive electrical component made of ring-shaped ferrite, used as a filter to suppress high-frequency interference in electrical circuits. A ferrite ring increases the inductance of a section of wire passing through it by several hundred (up to thousands) times, which ensures the suppression of high-frequency interference. Most often they are in the form of cylinders or parallelepipeds; can be removable with latches or non-removable cast. Such a filter, mounted on a solid wire, works as:

- inductance: part of the power of the RF wave is reflected back into the cable;

- absorber: part of the power of the RF wave is dissipated in ferrite, which is more preferable.

A ferrite filter installed on a multicore cable creates a common-mode transformer on this section of the cable, which, by passing antiphase signals, reflects (does not allow) common-mode interference.

But the magnetic cores, for example, the MSB series, which are made of a thin amorphous ribbon (18 ± 2 μm) based on cobalt, have a rectangular hysteresis loop and a significantly higher magnetic permeability compared to magnetic cores from permalloy alloys based on Fe-Ni and ferrite analogues. Having a very large inductance at the moment the current passes through zero, these products effectively block rapid changes in electric current, which could lead to electrical noise and interference, as well as damage to devices with short high-potential emissions. This class of products provides a higher effective suppression of interference, essentially eliminating the cause of their occurrence, significantly reduces losses compared to classical RC dampers and ferrite magnetic cores of a similar purpose. Structurally, the magnetic circuit of the tape is made as follows. The twisted tape magnetic core is placed in a rigid protective cylindrical container made of glass-filled polyamide and mechanically fixed with silicone sealant. The container provides reliable mechanical protection of the amorphous material and the preservation of its properties.

This utility model is industrially applicable and allows you to create a power cable with high protection against interference. Moreover, it is known that the effectiveness of the application of a shielding noise suppressing shell 4 made of tapes of metastable rapidly cooled alloys (amorphous or nanocrystalline) strongly depends on the number of tape layers in this shell. The inner layers of the shielding material having high saturation induction absorb the bulk of the excess magnetic field generated by the working power cable. The remaining part, which has a significantly lower intensity, is absorbed by the outer layers of the shielding material due to the high magnetic permeability. In the claimed utility model, only one layer of the tape winding of rapidly cooled alloys is indicated, which absorbs part of the excess magnetic field. But nothing excludes the possibility of applying a few words in such a shell. The current flows through the cable alternating, industrial frequency, so the field must also be variable, and the alternating field is only electromagnetic, i.e. electrical creates magnetic, which in turn generates again electrical, etc. The copper screen shields from the electric field, but does not protect from the magnetic field. It is precisely that the field is variable and prevents the magnetic from existing without an electric one. A variable magnetic generates a variable electric, and a variable electric generates a variable magnetic. Therefore, the alternating field is only electromagnetic. And the layer of noise-suppressing copper sheath 5 located on top of this shell 4 allows you to swallow the electrostatic field.

Claims (6)

1. An interference suppression cable containing a conductive core placed in a shielding noise suppression sheath made of tapes of metastable rapidly cooled alloys, which are overlapped along the length of the core with an overlap of not less than the thickness of the tape, and the outer shielding is coated with an external insulating coating, characterized in that it equipped with an additional shielding noise-suppressing copper sheath in the form of a cable stocking, located under an external insulating coating and covering Interference aniruyuschuyu sheath ribbons bystroohlazhdonnyh metastable alloys, and the magnetic core of annular shape, disposed at an end portion of the cable and a female shielding shell Interference ribbons bystroohlazhdonnyh metastable alloys. 2. The cable according to claim 1, characterized in that the tape is made of amorphous alloys. 3. The cable under item 1, characterized in that the tape is made of nanocrystalline soft magnetic alloys. 4. The cable according to claim 1, characterized in that the magnetic circuit is made in the form of cast ferrite. 5. The cable according to claim 1, characterized in that the magnetic circuit is made of a wound tape from metastable rapidly cooled alloys. 6. The cable according to claim 1, characterized in that the magnetic circuit is located in a clamping sleeve fixed to the end of the cable.

Images