CN1162208A

CN1162208A - Line segment of gas-insulation cable

Info

Publication number: CN1162208A
Application number: CN 97102621
Authority: CN
Inventors: M·莱永; 黎明; 刘荣生; D·温德马; B·莫列兹
Original assignee: Asea Brown Boveri AG Switzerland
Current assignee: ABB Inc Canada; ABB Schweiz Holding AG
Priority date: 1996-02-08
Filing date: 1997-02-08
Publication date: 1997-10-15

Abstract

The line section of a gas-insulated line contains a high-voltage electric conductor and a pressure pipe which is made from a thermoplastic material and filled with insulating gas. The pressure pipe holds the electric conductor on insulated supports. The pressure pipe has two pipes which are welded to one another on the end faces thereof, the end section being respectively widened to flare outwardly in the radial direction with bugle-shape. The line section can be manufactured at lowest price and has a optimum dielectric function as the characteristic.

Description

The part of path of GI cable

The present invention relates to the part of path of GI cable, the force pipe that this part of path comprises a high-voltage conductor at least and made by thermoplastic, the latter fills with insulating gas, and fixes an electric conductor on insulating support at least.GI cable has advantage to the big city transmission of power that is used to have many satellite cities, and is underground because they can be layed in, and can install with extension and unlikely to by the basic facilities of communicating by letter, water supply, air feed and sewage disposal limit significant impact being arranged.

For example from american documentation literature US-A-4,415,763 have been known by people this paper at a kind of part of path of described type at the beginning.In this patent documentation, a kind of GI cable has been described, its structure is as follows: in cable, one is filled with Compressed Gas SF ₆, settled a high voltage electric conductor in the pipe made by insulating material (as the typical material polyethylene).The coating that has one deck to be made of electric conducting material or semi-conducting material on the outer surface of this root insulated tube, this layer works with the field control mode, can conduct the reverse current that may occur where necessary.

An object of the present invention is to provide a kind of as this paper as described at the beginning type, with low cost and plain mode manufacturing and part of path with good dielectric property.

A kind of part of path of GI cable, at least comprise a high voltage electric conductor, with fixing force pipe this at least one electric conductor, make and fill insulating gas by thermoplastic by insulating support, it is characterized by: force pipe is equipped with two pipeline sections that its end face is welded together each other at least, and in the relative end of pipeline section, they are each comfortable radial expansion and flare Face to face.

Part of path of the present invention need not be expensive flange connect, and can be welded to one another by the pipeline section of piecemeal thermoplastic material being made together, thus can be at a low price, make apace.When two pipeline section welds in succession, also can take into account overlap joint at the radially tubaeform expansion mouthful end face of two pipeline sections.This expansion mouth has shielded the corner angle that two pipeline section commissures exist effectively, therefore need not take addition thereto just can improve the dielectric property of GI cable.This kind expansion mouthful can realize with plain mode by means of conical instrument, when the end face of the overlap joint each other heating of pipeline section to be welded, conical instrument is pushed pipe end and formed two expansion mouths with very little pushing force.

The preferred embodiments of the present invention and more obtainable thus advantages can further specify as follows according to accompanying drawing.

Fig. 1: the vertical view of the radial section of GI cable part of path form of implementation of the present invention.

Fig. 2: by the part of path of Fig. 1, along the vertical view of II-II cross section according to direction shown in the arrow.

Reference symbol:

1 GI cable

2 insulating supports

3 force pipes

4 electric conductors

5 weld seams

6,7 pipeline sections

8 loop lines

9 wire braid

10 semiconductor layers

11 insulating coatings

12 semiconductor layers

13 suppress the leakage current layer

In two figure, identical reference symbol is represented the parts of same function.Part of path in the GI cable shown in Fig. 1 and Fig. 21 comprises an electric conductor 4 that places force pipe 3 central authorities on pin type insulating support 2, and the latter has axial symmetrical structure, hollow, is in high potential, for example 220KV.Force pipe 3 is made (for example making insulating material with a kind of thermoplastic polymer) by insulating material, fills in the pipe with insulating gas, for example SF ₆For the purpose of part of path electrostatic screen, this thermoplastic body can filled conductive material, for example carbon black.The most important thing is that the thermoplastic body is made of the non-crosslinked material, and under the temperature that improves, can be shaped well and weld.Suitable thermoplastic material for example is a high density polyethylene (HDPE).

Force pipe 3 is to be made of about 4-12 rice, the pipeline section that is welded to one another at end face.At weld seam 5 places of two pipeline sections 6,7 in succession, two tube section ends that are welded to one another are extended to tubaeform.The diameter of the conical expansion at weld seam 5 places is only than the not changing unit of pipeline section 6,7 more bigger (about 2%～4%), and this effective dielectric barrier for the corner angle of commissure and discontinuity of materials is enough.

It is suitable coming the thermoplastic of stowing pressure pipe with electric conducting material (for example especially carbon black), because can realize GI cable 1 high efficiency electrostatic shielding to external world on the one hand in this way, and force pipe adds certain current potential on the other hand, and the weld seam 5 that forms for pipeline section 6,7 end regions provides good especially shielding.

Under the polyphase system situation in each is placed in an isolated pressure pipe mutually, if with loop line that is used to accept offset current of these force pipe arranged parallel, generally just enough.Yet the advantage of such loop line is can place on the outer surface of force pipe or in the force pipe.By Fig. 1 and Fig. 2 can see on the outer surface of force pipe 3, arrange be used to accept sealing current or geoelectric loop line 8.The advantage of this loop line 8 is to have the braid 9 that encases force pipe as flexible pipe, and this braid is made of electric conducting material, for example based on the wire braid of copper or aluminium or copper alloy, aluminium alloy.

The layer 10 that is constituted, surrounded by wire braid 9 by semi-conducting material is coated on the outer surface of force pipe 3.This semi-conductor layer to external world electrostatic screen GI cable 1.This screen effect need not wire braid 9 just can realize.If put wire braid 9 as mentioned above, then layer 10 makes the electrostatic field homogenizing of the GI cable 1 serious distortion that each solid conductor by wire braid 9 causes simultaneously.On the inner surface of the pipeline section 6,7 of facing electric conductor 4, arranged to suppress the layer 13 of leakage current.This thin layer comprises a kind of material that can at high temperature discharge water outlet, especially for example with gibbsite (hydrargillite), and the aluminium hydroxide of crystallization (Al (OH) ₃) form.If at GI cable 1 run duration, the metallic with sharp corner angle is deposited on the layer 13, and then these corner angle acutely generate heat when partial discharge takes place.The Al (OH) that exists in the corner angle zone ₃Therefore localized heating discharges low amounts of water to hundreds of degree centigrade, the metal material reaction of the latter and band corner angle, and this material oxidation fallen, formation does not have dielectric particle corner angle, harmless.The vestige that can avoid leakage current in this way fully and be produced by these leakage currents occurs on the inner surface of force pipe.

Also can use other material and replace Al (OH) ₃, these materials can discharge the material of gas or steam-like when heating, and the heating corner angle of the latter and metallic react.

Dispose by the filling semi-conducting material in case of necessity and discharge gas or layer 10 and layer 13 that the polymer of the material of steam is made, will have special advantage.If the polymer that adopts the polymer of the thermoplastic that constitutes force pipe 3 to use as these thin layers, then Tu Fu force pipe can be in the mode of saving money especially, for example adopts co-extruded to form the polymer of force pipe and the polymer of filling semi-conducting material and/or the polymer that filling discharges gas or steam and makes.The force pipe that adopts this mode to make has the single polymers matrix that plays different action face thin layers.Because this structure has farthest been avoided the interior hole of rack surface of two layers 10,13, thereby reduced the undesirable partial discharge of appearance in the coating pressure tube material basically.

Can also be equipped with the overcoat 11 that constitutes by insulating material by giving the electric conductor 4 that places in the force pipe 3, thereby further improve the dielectric strength of GI cable part of path.For fear of undesirable dielectric load between electric conductor 4 and insulating coating 11, electric conductor has the layer 12 that one deck is made by semi-conducting material on its outer surface, configuration insulating coating 11 on layer 12.

Claims

1, the part of path of a kind of GI cable (1), at least comprise a high voltage electric conductor (4), with fixing force pipe (3) this at least one electric conductor (4), make and fill insulating gas by thermoplastic by insulating support (2), it is characterized by: force pipe (3) is equipped with two pipeline sections (6 that its end face is welded together each other at least, 7), and in the relative end of pipeline section, they are each comfortable radial expansion and flare Face to face.

2, according to the described part of path of claim 1, it is characterized by: thermoplastic material is filled with electric conducting material, for example, especially adopts carbon black.

3, according to claim 1 or 2 described part of paths, it is characterized by: configuration control of Electric potentials layer (10) on the outer surface of pipeline section (6,7).

4, according to the described part of path of claim 3, it is characterized by: control of Electric potentials layer (10) comprises semi-conducting material.

5, according to the described part of path of one of claim 1 to 4, it is characterized by: on the inner surface of electric conductor (4), dispose inhibition leakage current layer (13) at pipeline section (6,7).

6, according to the described part of path of claim 5, it is characterized by: suppress leakage current layer (13) discharges gas or steam when being included in high temperature material.

7, according to the described part of path of claim 6, it is characterized by: this kind material is Al (OH) ₃

8, according to the described part of path of one of claim 4 to 7, it is characterized by: control of Electric potentials layer (10) and/or inhibition leakage current layer (13) respectively contain the filling semi-conducting material and/or at high temperature discharge the thermoplastic polymer of the material of gas or steam.

9, described according to Claim 8 part of path is characterized by: force pipe (3), control of Electric potentials layer (10) and/or inhibition leakage current layer (13) respectively contain with a kind of thermoplastic polymer.

10, according to the described part of path of one of claim 1 to 9, have the conduction sealing current, be configured in the electric conductor (8) on force pipe (3) outer surface, it is characterized by: enclosed electric conductor (8) comprises a wire braid (9) that encases force pipe (3) as flexible pipe.

11, according to the described part of path of one of claim 1 to 10, it is characterized by: be fixed on electric conductor (4) in the force pipe (3) and be insulated the overcoat (11) that material makes and surround.

12, according to the described part of path of claim 11, it is characterized by: between electric conductor (4) and insulating coating (11), disposed the layer of making by semi-conducting material (12).