CN2618268Y - Shielded controlling cable - Google Patents

Abstract

The utility model discloses a shielding control cable used as a signal transmission carrier for the control equipment at a high voltage substation with an intense electromagnetic interference environment. As is shown in the abstract figure, the prior shielding control cable adopts the copperbelt spiral wingding as a shielding layer while the utility model adopts a metal tube shaped shielding layer ([3] and [4])comprising the continuous longitudinal covering of a magnetic conductive material (like a shielding steel) and a conductive material. The two ends of the outer shielding layer ([3] and [4]) of the shielding control cable are connected with the ground, which relieves the interference of the disturbance sources on the cable connection equipment by the shielding method of the reflection and absorbsion. If the shielding layer comprises a shielding wire, the shielding wire can only be connected with the ground on the side of a sensitive element. The two ends of the shielding wire can not be connected with the ground at the same time, or else the interference will be introduced. The continuous longitude covering of the tube shaped conductive shield not only improves the reflection and the shielding of the high frequency interference, but also increases the absorption shielding and the magnetic field shielding function of the high and low frequency interference.

Description

A kind of shielding control cable

The utility model relates to a kind of control appliance power supply and signal of telecommunication transport vehicle, especially the shielding control cable that is made of conductor, insulating material, shield and plastic sheath.

The shielding control cable of selling on the market so far, is exactly this structure.The screen that shield effectiveness shields control cable preferably is to form by copper strips is wrapped, and general shielding control cable body then is to be made of aluminium foil and copper wire establishment wire netting.Screen one end ground connection is mainly disturbed electric field shielding action; Can play high frequency during two-terminal-grounding and reflect jamming-proof effect, but because there is the reason of mesh and vertically discontinuous (spiral winding) in it, this anti-tampering effect also is limited.Therefore, the fast transient burst interference be afraid of most of microelectronic device particularly under some electromagnetism strong interference environment, existing shielding control cable is difficult to be competent at.

At present, the control cable of high voltage substation employing is exactly this shielding control cable.Because the shield of this cable is by non-magnet material, and spirality is not vertically continuously.Therefore when shield was experienced the interference of high-frequency pulse string fast transient, the shielding control cable was because of the vertical discontinuous reflecting barrier effect that reduced of screen; Thin and the non-magnet material kelvin effect is poor because of copper strips again, make the shield that disturbs wave energy to penetrate this class formation enter cable core, disturb the terminal device that inserts cable.Flowing through as thunderbolt, powerful electric network fault electric current near the cable connection device place in power plant and the transformer station that the bus that is parallel to cable disturbs at formed fast transient of starting stage will be like this.This shielding control cable is lower for the shield effectiveness of this class electric current coupled interference and high-frequency electric field coupled interference, causes microelectronic device to lose the operate as normal ability sometimes, even causes components and parts to damage.

Task of the present utility model provides a kind of shielding control 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 that the screen that will shield control cable vertically packs into the seamless tubulose double layer screen body of atresia continuously by what magnetic conductive material and good conductor of electricity constituted, constitutes a kind of novel shielding control cable.

The tubulose good conductor of electricity outer shielding layer of this shielding control cable has better shield effectiveness to the reflecting barrier effect in high frequency harassing and wrecking source than copper strips lapped shielding layer; Tubulose magnetic conduction internal shield makes and penetrated the High-frequency Interference ripple that outer shielding layer covers layer in arriving frequently and convert eddy current to, with the form of heat energy it is consumed, produce to absorb shield effectiveness, this shield effectiveness be existing shielding control cable can not compare.In addition, novel shielding control cable is that existing shielding control cable is not available aspect magnetic shielding and to the shield effectiveness in low frequency disturbance source.

Adopt this shield effectiveness better to shield control cable and can make cable introduce the conductibility interference intensity further to be reduced even eliminates, the electrical network serious accident that can cause microelectronic device incorrect operation or component wear to cause because of the interference of cable introducing is minimized bottom line and even elimination originally; For the safe operation of electrical network, reliable power supply provide powerful guarantee, its economic benefit and social benefit are clearly.

The using method of novel cable is: the internal shield of shielding control cable is to adopt the frequency of electroplating surfaces with tin (aluminium) to cover steel.For guaranteeing that cable has good bending property, adopt the vertical bag of wrinkle steel band of model to form; Outer shielding layer packs by electric conducting material is vertical well.Control cable screen two ends closely link to each other with bin by special-purpose connector with control (protection) cabinet with the metal-back system terminal box of connected equipment, and are easy to connect and contact resistance is little.Terminal box and control (protection) cabinet and ground network adopt bind mode ground connection, and cable shield is realized seamless link by the indirect earth mat of the metal shell of terminal device, for equipment provides tight shielding protection effect.When high frequency harassing and wrecking electric current flows through from screen, the reverse magnetic linkage that produces because of the screen electric current is resisted the interference of external magnetic field, can weaken the interference strength that high frequency magnetic field produces inner wire largely; The high frequency magnetic linkage that passes through the good conductor of electricity screen for part is during through shielding steel shield, and the High-frequency Interference ripple produces eddy current on shielding steel surface and is absorbed, thereby has more effectively suppressed the interference of electromagnetic field of high frequency by the cable pairs connecting device.

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

Accompanying drawing 1: be the structural representation of shielding control cable.[1] among the figure is cable core, extrudes plastic insulation and form outside single strand of copper wire or multiply fine copper wire stranded conductor; [2] be polyethylene stranding colligation layer; [3] be the cast internal shield (, adopting wrinkle shape structure) that magnetic conductive material is done for the flexibility of cable; [4] be the cast internal shield that good conductor of electricity is done; [5] be PVC external insulation and oversheath.

Accompanying drawing 2: be the practical wiring schematic diagram of DC power cabinet with the shielding control cable.[6] in the accompanying drawing, [7] are metal cabinet, direct current system insulating monitor cabinet and the signal transducers [8] of shielding control cable two ends connecting device; [9] be power station ground network; [10] screen one end of built-in weak signal shielding control cable (screen is the copper wire knitted conductor) is through the direct ground connection of casing, and the other end is earth-free, has only required the electric field shielding effect.The recommendation of all shielding protection ground connection is adopted bind mode ground network, and should not adopt star fashion ground connection.

When power station scope thunderbolt, carry out High-Voltage Electrical Appliances operations or electrical network generation ground short circuit fault etc. when producing the harassing and wrecking of forceful electric power magnetic, [3] and [4] two-layer shielding two-terminal-grounding interference that the harassing and wrecking source is produced shielding action of having played reflection and having absorbed, be unlikely to disturb heart yearn; [10] effect of the screen one end ground connection of weak signal line is to prevent that direct current supply line from producing interference in operating process, and playing the electric field shielding effect only needs an end ground connection to get final product, and two-terminal-grounding can be lost more than gain disturbing the lead-in cable heart yearn.

Claims (3)

1. (1) a kind of shielding control cable that constitutes by heart yearn, insulating barrier, screen (or increasing armour) and sheath.It is characterized in that: the shielding control cable adopts vertically continuous tubular shielding layer;
2. (2) shielding control cable according to claim 1 is characterized in that: adopt higher material of permeability and good electric conducting material to constitute many screens;
3. (3) the higher screen of permeability according to claim 2 is characterized in that: adopt the vertical bag of wrinkle steel band to form.