CN2052142U

CN2052142U - All-plastic low-voltage power cable with shielding zero line

Info

Publication number: CN2052142U
Application number: CN 89207291
Authority: CN
Inventors: 尤大千; 蒋礼堂
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-05-13
Filing date: 1989-05-13
Publication date: 1990-01-31

Abstract

The utility model discloses an all-plastic low-voltage power cable with a shielding zero line, belonging to a cable used as a wiring in low-voltage power network work. The cable comprises a four-core and a five-core cable, and a fourth and a fifth core line used as the shielding zero line are composed of a plurality of thin conducting lines closely arranged on a plane and integrally coiled outside the core lines at a large pitch mode so as to compose a single-layer or a double-layer shielding zero line. The cable has reliable anti-interference performance and can raise the sensitivity of the protection device of the head end when the protection device has the single-phase short circuit and eliminate the harm caused by over voltage generated by the thunderbolt electromagnetic effect.

Description

All-plastic low-voltage power cable with shielding zero line

The utility model belongs to four-core, the 5-core power cable of distribution line in the low voltage electric network.

At present, various low pressure four-cores, 5-core power cable, as each heart yearn of phase line and zero line all is respectively that parallel arranged and four of being separated by insulating barrier or five round conductors or multi cord constitute, and except the oil compression cable skin is surrounded by the sheet lead, other cable is all less than shielding.Therefore, these cables certainly exist following three shortcomings:

1, interference free performance is poor, and when containing high order harmonic component in the electric current that cable itself is carried, cable can produce electromagnetic interference to the electronic equipment around it; Otherwise extraneous electromagnetic interference also can be coupled on the cable core, and the various electric devices that join with cable are produced electromagnetic interference.

2, a nulling loop impedance is big mutually, and circuit single-phase short circuit current value is reduced, and influences the sensitivity of head end protective device when single-phase short circuit.It is to be noted especially: in the connecting to neutral system of power supply neutral-point solid ground; when cable one insulate breakdown mutually and a phase ground connection is taken place; because of its earth short circuit current value very little; deficiency causes jeopardizing the electric equipment and the personal safety of whole system so that the overcurrent protective device of circuit head end moves effectively.

3, along the cable that lays in the skyscraper, because of unshielded layer, under the galvanomagnetic effect effect of powerful lightning current, produce overvoltage unavoidably, cause the damage or the puncture of insulating barrier.

The purpose of the utility model is: a kind of anti-electromagnetic interference, anti lightning galvanomagnetic effect are provided, can improve four-core, the 5-core power cable of circuit one phase earthing short circuit protection sensitivity.

For achieving the above object, I am in 88208766.5 " the serial totally-enclosed shielding zero line power cables " at number of patent application, a kind of four-core, five-core cable with totally-enclosed shielding zero line of individual layer spiral tubular bridging type made from metal tape is provided, thereby overcome above-mentioned three shortcomings.But, consider when making cable, unavoidably because of technologic defective causes local overlap joint bad (lap-joint's oxidation or Insulation Material enter), so that when conduction, produce spiral (pipe) shape electric current, cause the interference of inductance type to cable.

For overcoming the above-mentioned defective that may occur; I am in application number is 88214810.9 patent application; four-core; 5-core power cable adopts following structure: quad is to be made of three equal circular or fan-shaped plain conductor or multi cords of sectional area that are surrounded by insulating barrier as three heart yearns of phase line; quad as working zero line or protection zero line (PE or PEN) then is made of two strip metal bands; they constitute two toroidals that are in contact with one another and the totally-enclosed shielding zero line that partly overlaps with opposite turning to three parallel heart yearn one coiling claddings.Outside the shielding zero line, be surrounded by insulating barrier; similar with it; 5-core power cable is to be made of four equal plain conductor or multi cords of sectional area that are surrounded by insulating barrier as four heart yearns of phase line and working zero line; the 5th heart yearn as protection zero line (PE) then is made of two strip metal bands; they constitute two toroidals that are in contact with one another and the totally-enclosed shielding zero line that partly overlaps with opposite turning to four parallel heart yearn one coiling claddings.The shielding zero line is surrounded by insulating barrier outward.Constituting the quad of the quad that shields zero line and all available wire netting sleeve pipe by the lametta braiding of the 5th heart yearn of five-core cable substitutes.

The lv power cable of above-mentioned two patent applications, its advantage is unquestionable, but considers from its processing, will cause cost to improve when adopting metal net shielding zero line; And when adopting the single, double spiral bridging type shielding zero line of being made by metal tape, manufacturing cost will decrease, and so its shortcoming is that flexibility is relatively poor, and is not flexible in use.

The utility model is intended to overcome the shortcoming that above-mentioned two classes have the higher and flexibility difference of processing cost that the cable that shields zero line exists respectively, provide a kind of easy to process, flexibility good and performance with excellent " the serial lv power cable that the shielding zero line is arranged.

The utility model is to realize above-mentioned purpose like this: (referring to figure)

The quad that this is novel, it is separated with insulating material by three each other as three heart yearns of phase line, and circular or fan-shaped plain conductor that cladding, sectional area equate or multi cord constitute, quad as working zero line or protection zero line (PE or PEN) then is to be made of the some thin wires of closely arranging in one plane, these thin wires are reeled in the coarse pitch mode, with three parallel phase line one claddings, constitute the shielding zero line of following three kinds of forms; 1. the single-layer shield zero line of only reeling with direction; 2. be in contact with one another the two-layer equations shielding zero lines of (conducting) by reel in the opposite direction two layers of forming of two groups of leads; 3. reel with a certain direction by one group of lead and constitute the zero line internal layer, in the internal layer outside insulating barrier is arranged again, the zero line skin that constitutes with the second group of lead of reeling in the other direction in this insulating barrier outside, isolate two-layer equation shielding zero line (sip bow raw meat～2 insulated wire than bluffing the male cangue of  error  bucktooth cangue big shield tool, also can constitute the shielding zero line that inductance is cancelled out each other) thereby constitute.In addition, the another kind of form of this shielding zero line is with longitudinally three phase lines and working zero line one being cladded along the metal tape that laterally is pressed with ripple, making the shielding zero line of bellows-type.Layer is added with insulating sleeve outside above-mentioned zero line.

Described quad and five-core cable, its shielding zero line is divided into two kinds of 50% area of section that its cross section gross area approximates a phase line area of section and its cross section gross area approximates a phase line, thereby constitutes four kinds of cables: 1. uiform section four-core power cable; 2. common four-core power cable; 3. uiform section 5-core power cable; 4. common 5-core power cable.For all two-layer equation shielding zero lines, the total sectional area of its two layer conductor should equate or approaching equating.

Description of drawings:

Institute's drawings attached is that the quad of fan-shaped plain conductor is an example with the phase line cross section only, and its structure is shown; The five-core cable structure is identical with it.

Fig. 1 a-single-layer type shielding zero line quad is vertically shelled a layer schematic diagram.

Fig. 1 b-single-layer type shielding zero line quad schematic cross section.

Fig. 2 a-two-layer equation shielding zero line quad is vertically shelled a layer schematic diagram.

Fig. 2 b-two-layer equation shielding zero line quad schematic cross section.

Fig. 3 a-interlayer has the two-layer equation shielding zero line quad of insulation vertically to shell a layer schematic diagram.

Fig. 3 b-interlayer has the two-layer equation shielding zero line quad schematic cross section of insulation.

Fig. 4 a-bellows-type shielding zero line quad is vertically shelled a layer schematic diagram.

Fig. 4 b-bellows-type shielding zero line quad schematic cross section.

Wherein: the 1-heart yearn; 2-core insulation layer; The 3-insulating case; 4-shields zero line; 4 '-internal layer shielding zero line; 4 " outer shielding zero line; 5-shielding zero line oversheath; Insulating barrier between the inside and outside layer shielding of 6-zero line.

This power cable advantage is as follows:

When 1, transmitting electric power, can not disturb electrical equipment generation on every side; Also eliminated external electromagnetic interference to being connected the impact of the electrical equipment on this cable.

2, can avoid powerful thunder and lightning galvanomagnetic-effect to produce puncture or damage that overvoltage causes, improve the lightning-arrest effect of skyscraper and reliability.

3, can improve the sensitivity of circuit head end overcurrent protective device, make cable and the electric equipment that connects thereon is effectively protected.

4, can eliminate issuable spirality electric current in 88208766.5 applications, above-mentioned three advantages are ensured conscientiously.

5, easy to process, flexibility is high, be easy to the construction.

Claims

1, a kind of low pressure four-core that armouring and no armouring are arranged, 5-core power cable, of the present utility model have the low pressure full plastic power cable of shielding zero line to be characterised in that: the 5th heart yearn as the conduct protection zero line of working zero line or protection quad of zero line and 5-core power cable of four-core power cable, the all useful some thin wires of closely arranging in one plane constitute, these thin wires are reeled in the coarse pitch mode, with four heart yearn one claddings of three heart yearns or the five-core cable of quad, constitute the shielding zero line of following three kinds of forms: the 1. single-layer shield zero line of only reeling with a direction; 2. by two groups of leads two-layer equations shielding zero lines that two layers of forming are in contact with one another of reeling in the opposite direction; 3. being reeled with a certain direction by one group of lead constitutes the zero line internal layer, in the internal layer outside insulating barrier is arranged again, constitutes the zero line skin in this insulating barrier outside with second group of lead of reverse coiling, isolates two-layer equation shielding zero line thereby constitute; The another kind of form of shielding zero line is with longitudinally three or four heart yearn one being cladded along the metal tape that laterally is pressed with ripple, making the shielding zero line of bellows-type.

2, the low pressure full plastic power cable that the shielding zero line is arranged according to claim 1, it is characterized in that: described shielding zero line, what be divided into that the cross-section gross area approximates a phase line area of section approximates two kinds of phase line area of section 50% with its area of section, thereby constitutes uiform section four-core power cable, common four-core power cable, uiform section 5-core power cable, common 5-core power cable.

3, the low pressure all-plastic cable that the shielding zero line is arranged according to claim 1 and 2 is characterized in that: the total sectional area of 2 layer conductors of above-mentioned two-layer equation shielding should equate or approaching equating.