CN2525649Y

CN2525649Y - Coaxial cable

Info

Publication number: CN2525649Y
Application number: CN 01240245
Authority: CN
Inventors: 黄叙银
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-06-05
Filing date: 2001-06-05
Publication date: 2002-12-11
Anticipated expiration: 2011-06-05

Abstract

The utility model discloses a coaxial cable as the high-frequency signal transmission medium for the high voltage transformer substation with strong electromagnetic interference environment. Showed by the chart 3.1, in the utility model, the outer insulating layer of the structure of the prior coaxial cable is additionally provided with a screen magnetic (such as the cover steel) to construct a metal tubular shape outer shielding layer [5] and a plastic overcoat [6]. When the utility model is used, two ends of the outer shielding layer [5] of the coaxial cable are connected with the ground, restrain the low frequency disturbances and wear off part of the high frequency interference; one end of an outer conductor [3] used as a signal circuit is connected with the ground, while the other end is connected with the ground by capacitor so as to remove the high frequency interference permeating the outer shielding layer. The utility model solves the problems of misoperation of differential protection of the circuit high frequency caused by the blocked high-frequency passage when the common impedance coupling interference emerges with two ends of the outer conductor [3] of the coaxial cable connected with the ground.

Description

A kind of coaxial cable

The utility model relates to a kind of high-frequency signal transmission medium, the especially coaxial cable that is made of inner wire, insulating material, outer conductor and plastic sheath.

So far, the coaxial cable of selling on the market is exactly this structure.It has only inside and outside two-layer conductor, is applicable to that mainly radio, broadcasting, TV and similar electronic product make transmission line.

At present, the used high-frequency signal transmission wire of high-voltage power line carrier wave also is this coaxial cable.Because the outer contact of this cable promptly is that screen is again the signal circuit line, when pressing shielding requirements, under grid failure state, when the big electric current of low frequency passes through screen, high-frequency signal is produced for impedance coupling strong jamming its two-terminal-grounding.This interference is blocked hf channel, even causes device damage.Cause circuit carrier current protection incorrect operation therefrom, the safe and stable operation of crisis electrical network and the reliability of power supply.

Task of the present utility model provides a kind of coaxial cable, makes it to be applicable to the high voltage substation environment of strong electromagnetic.For reaching this purpose, solution of the present utility model is to add one deck magnetic conductive material again to make outer shielding layer on the external insulation layer of similar existing coaxial cable structure, constitutes triaxial cable.Using method is: with the outer shielding layer two-terminal-grounding of coaxial cable, low-frequency current can only be flow through from outer shielding layer, this has not only been avoided the big electric current of low frequency that the common impedance coupling that high-frequency signal produces is disturbed, and, also can weaken the interference strength that high frequency magnetic field produces inner wire largely because of frequency covers the interference that layer reverse magnetic linkage of electric current generation resisted external magnetic field; With intermediate layer conductor one end ground connection, the other end is through capacity earth, the high frequency magnetic linkage that part is passed through outer shielding layer produces reflection and eddy current loss during through the intermediate layer conductor, and the high screen reverse magnetic linkage that produces of electric current and resist the interference of high frequency magnetic field frequently, thereby further suppressed the inductive coupled interference of high frequency magnetic field.Remedied existing coaxial cable fully helpless shortcoming has been disturbed in the common impedance coupling that low-frequency current produces.

Below in conjunction with drawings and Examples the utility model is described in further detail:

Accompanying drawing 1: be the structural representation of triaxial cable.[1] among the figure, [3] are inner wire and outer conductor, are made of soft copper conductor and copper wire knitted conductor respectively; [2] be insulator in the polyethylene; [5] be the cast outer shielding layer (, adopting sandwich construction) that magnetic conductive material is done for the flexibility and the screen cross section of cable; [4], [6] are poly-Pearl ethene external insulation and oversheath.Wherein [5] should adopt permeability magnetic material to make the vertical combined shielding layer of tubulose as the low-frequency current screen.Its production technology is seen below continuous this patent divisional applied file.

Accompanying drawing 2: be the practical wiring schematic diagram of triaxial cable.[7] in the accompanying drawing are originally to be not less than 100 square millimeters copper conductor along what cable louding laid; [8], [11] are the metal cabinet or the casings of coaxial cable two ends connecting device; [10], [11] are the metal shells of coaxial cable two ends coupling arrangement.[3] the terminated line terminal of (copper wire knitted conductor) and through the direct ground connection of shell: other end upper connecting terminal is after the capacitor and the earthing of casing; [5] two ends of (outer shielding layer) connect the metal cabinet or the casing of terminal device reliable ground respectively.

When electrical network generation ground short circuit fault produced strong low-frequency current, it can only flow through from [5] and [7], and can not flow through the outer conductor [3] as the signal circuit line.Thereby, eliminated the common-impedance coupling interference that original coaxial cable outer conductor two-terminal-grounding produces.In addition, [5] are to adopt permeability magnetic material to make the vertical combined shielding layer of tubulose, not only low frequency magnetic field are had good magnetic conduction by-passing, and high frequency magnetic field generation eddy current loss is undermined the reflection dissipation role.Thereby weakened the induction coupled interference.The external shield of electromagnetic field of high frequency pass to(for) part will be absorbed by [3] (internal shield).Its screening effectiveness is far above existing coaxial cable.

Claims

A kind of coaxial cable that constitutes by inner wire, interior insulation, outer conductor, external insulation, screen and sheath, it is characterized in that: the skin at two coaxial cables that are made of inner wire, insulating material, outer conductor and plastic sheath adds vertical continuous tubular outer shield layer (5) and the plastic sheath (6) that one deck is made of permeability magnetic material again, forms triaxial cable.