CN1246968A - Device for cable joint and rotating electrical machine comprising such a device - Google Patents

Abstract

The invention relates to a device for various cable joints, in particular for bending cable joints. The cable joint comprises two cables (6,7;18,19;45,46) and a splice joint (9;16;43), which splice joint (9;16;43) is added between the cables. The device is characterized in that it comprises a support (1;15,40,41) intended to be applied to the joint so that the parts (6,7,9;16,18,19;43,45,46) forming the joint remain substantially immobile relative to each other, and at least one fixing member (11,12;21,22;50,51) with which the support is elastically fixed to the cable and which is capable of absorbing dimensional changes of the cable caused by thermal expansion or contraction. The invention also relates to a rotating electric machine comprising a stator with windings leading out through stator slots and a rotor, characterized in that it comprises the above-mentioned means for cable connection.

Description

Be used for the device of cable joint and comprise the electric rotating machine of this device

The present invention relates to a kind of cable joint that is used for, especially for the device of the cable joint that molding is good in advance on the various curved cables, preamble as claimed in claim 1 is described.

The invention still further relates to a kind of electric rotating machine as described in the preamble as claim 24.

A cable joint generally includes two cables and a joint, and this joint is assemblied between each cable, so that bond them together.

Cable joint is assemblied in usually and is positioned on the underground straight cable, or is assemblied on each cable ladder.Cable joint and cable lock together each other securely.

Yet, owing to use various cables, that is the High-Voltage Insulation electric conductor, so in the stator winding of an electric rotating machine, that cable joint will be assemblied in will be curved (crooked) cable, and thereby be subjected to a kind of novel stress, that is bending stress.Cable joint and each cable are also because thermal expansion and mechanical oscillation former thereby stand motion.Another problem relevant with this use is that it can not be fixed on each cable and cable joint in the common fastener.

A kind of device that is used for each cable joint of encapsulation is disclosed in patent documentation EP 0 732 787.In Fig. 2 of this patent documentation, illustrate a stabiliser bar that adheres to along joint.The purposes of this bar provides the structural stability of joint, especially prevents the sharp turn.Utilizing various compression securing members that this bar is fixed to the outer of cable puts.This patent documentation also discloses a kind of soft (or hard) shell, and this shell is configured to surround cable joint and fills a kind of curable encapsulant, so that sealing cable junctions.Encapsulant is solidified into a kind of gelatinous thickness body.Be used for the encapsulation cable joint particularly other device of various different sleeve design known from for example patent documentation DE 34 41 311 and EP 0 316 911.

Yet, in known devices, there is not a kind of device can keep each parts that form cable joint (that is two cable and cable joint) to maintain static each other, and simultaneously, can absorb cable dimension and various change and not damage this device, size changes mainly because thermal expansion and contraction cause.

The example of some electric rotating machines relevant with present circumstances is: synchronous machine class, standard asynchronous motor and dual-feed formula electric machinery, alternating current machine class, the application in asynchronous static converter cascade, outer buttons rotating motor class and synchronous flux electric machinery.

Be specially adapted to a kind of electric rotating machine according to device of the present invention, this electric rotating machine is being used for sending the power station of electric power as generator work.

The purpose of this invention is to provide a kind of device that is used for various cable joints, this device is used for addressing the above problem, and especially solves the problem at various curved cable joints place.

This purpose reaches by a class device as described in the preamble of claim 1, and claim 1 has provided the feature described in the characteristic of this claim.

Another purpose provides a kind of electric rotating machine, has solved the problem of being discussed in this motor.This purpose reaches by a class motor as described in the preamble of claim 24, and claim 24 has provided the feature described in the characteristic of this claim.

Therefore, by providing a kind of device with the strutting piece form, be used to be added to cable joint, so that each included parts keep maintaining static each other basically in the joint, described strutting piece comprises at least one fixed component, utilize this fixed component that strutting piece flexibly is fixed on the cable, and described fixed component can absorb the change of the cable dimension that causes owing to thermal expansion or contraction, this advantage reaches: joint is straight and keeps is straight; Connector area is not vulnerable to bending stress.Simultaneously, the change of cable dimension is absorbed, so butt joint is without any adverse effect.As a result, this device produces a very reliable and very safe cable joint.

This device also has such advantage, and promptly it not only can be used for various high-voltage motors, and can be used for other situation, in these cases, need strutting piece be used for a cable joint, especially for various curved cables.

According to device of the present invention, plan preferably in each winding, to use for the various cables of its use, and preferably has one type cable hard, the extrusion molding insulator, that is be used for the sort of type cable of distribution at present, as twisted polyethylene cable or have those cables of ethylene propylene rubber insulated body.This cable comprises: an inner wire, an interior semi-conductive layer, a hard insulating barrier and an outer semiconducting layer, above-mentioned inner wire comprises one or more strands of twisted wire parts, interior semi-conductive layer surrounds this conductor, a firm insulating barrier surrounds this inner conducting layer, and outer semiconducting layer surrounds insulating barrier.These cables are soft, in this case, cable be soft be an important properties because be used for production technology according to device of the present invention mainly based on some winding systems, wherein winding is formed by cable, this cable was bent between erecting stage.The flexibility of XLPE cable is equivalent to the radius of curvature of an about 20cm concerning having the cable that diameter is 30mm, and is equivalent to the radius of curvature of an about 65cm concerning having the cable that diameter is 80mm.In this application, term " bendable " is used for representing that winding can be bent to a radius of curvature downwards, and this radius of curvature is about 4 times of cable size, the 8-12 that preferably is about cable size doubly.

Even winding should be made when it is crooked and when it is subjected to thermal stress during operation, also keep its character.Importantly, in this case, each layer keeps their bonding forces each other.Here the material character of each layer, particularly their elasticity and thermal coefficient of expansion are conclusive.For example, in an XLPE cable, insulating barrier is made up of cross-link low-density polyethylene, and each semi-conductive layer is made up of the polyethylene that wherein is mixed with carbon ink and metal particle.The stereomutation that causes owing to the temperature fluctuation result is absorbed fully along with the change of cable radius, and because the thermal coefficient of expansion in each layer is with respect to the elasticity of these materials, smaller difference is arranged between them, so radial expansion can take place, and not loss of the bonding force between each layer.

Should only regard some above-mentioned combinations of materials as some examples.Satisfy some conditions of defined and satisfy semiconductive some other combination, also belong to scope of the present invention naturally, semiconductive just has 10 ^-1-10 ⁶The resistivity of (as 1-500ohm-cm or 10-200ohm-cm) in the ohm-cm scope.

Insulating barrier can be for example by a kind of hard thermoplastic as low density polyethylene (LDPE) (LDPE), high density polyethylene (HDPE) (HDPE), polypropylene (PP), polybutene (PB), polymethylpentene (" TPX "); Various cross-linked materials such as crosslinked polyethylene (XLPE); Or rubber such as ethylene-propylene rubber (EPR) or silicon rubber composition.

In can make with identical stock with outer semiconducting layer, but wherein be mixed with the particulate of electric conducting material, as carbon black or metal powder.

That the engineering properties of these materials, particularly their thermal coefficient of expansion are subjected to wherein whether to be mixed with the influence of carbon black or metal powder is smaller-at least in desired ratio, to reach according to conductivity essential to the invention.Therefore insulating barrier and each semi-conductive layer have substantially the same thermal coefficient of expansion.

EVAc/acrylonitrile-butadiene rubber (EVA/NBR), butyl grafted polyethylene, ethylene butyl acrylate copolymer (EBA) and ethylene ethyl acrylate copolymer (EEA) also can constitute the polymer that is applicable to each semi-conductive layer.

Even when adopting dissimilar materials as substrate in various different layers, preferably their thermal coefficient of expansion is all substantially the same.The combination of various materials listed above is exactly this situation.

Various material listed above has reasonable elasticity, and they have E＜500MPa, preferably＜and the E modulus of 200MPa.Any fine difference in each layer between the material coefficient of thermal expansion coefficient, elasticity is enough to flexiblely be absorbed in the radial direction at this, does not therefore have crackle to occur, or any other damage; And each layer can not be separated from each other.Material in each layer is resilient, and the bonding force between each layer have at least with these materials in the most weak identical magnitude of material.

The conductivity of two semi-conductive layers is enough to make basically the current potential along every layer to equate.The high electric field in enough sealing cables of the conductivity of outer semiconducting layer, but do not have enough to hang down to owing to the induced current on this layer longitudinal direction produces great loss.

Therefore, each in two semi-conductive layers all constitutes an equipotential surface basically, and these layers will seal the electric field between them basically.

Certainly, can stop the one or more additional semi-conductive layers of configuration in insulating barrier without any thing.

Because, engage good cable herein and form high-tension cable mainly for using in cable joint according to device of the present invention, so its advantage is outstanding especially here, it is that each cable is made of high-tension cable that special characteristics are said to be.

Additional being characterised in that: high-tension cable have one in the 20-250mm scope diameter and one at 80-3000mm ²Conductive area in the scope.

Other characteristics of the present invention and advantage are seen and will be become clearly from remaining dependent claims.

As a special advantage, fixed component is made with a kind of elastomeric material.

According to the first embodiment of the present invention, strutting piece comprises at least one rigidity yoke piece, and the inner surface of this yoke piece wherein promptly is adapted to the external shape of this joint towards the shape on the surface of joint.The strutting piece of getting the yoke piece shape has the very advantage of light structure, this kind very light structure easily with compression molding or casting die manufacturing.Yoke piece also is easily installed on the joint.Perhaps can use several yoke pieces, for example can be made up of three yoke pieces by a strutting piece, each yoke piece all has substantially the same shape.

As another advantage, each yoke piece can have an elongated shape and terminate in two ends, and described fixed component can comprise an elastic clamp device, so that described yoke piece is located and is fixed on the cable of two joints.

According to second embodiment, strutting piece is characterised in that: it comprises a sleeve pipe.The shape of this sleeve pipe is adapted to joint, and the internal diameter of its middle sleeve is the size identical with the maximum outside diameter of cable joint basically.

According to one of described second embodiment favourable modification, this sleeve pipe comprises two axial sleeve portions, and they help strutting piece is assembled on the joint.Sleeve pipe is divided into the some parts that has the gap between them, also is favourable to cooling joint.

According to the sleeve pipe of this second embodiment or sleeve pipe each several part also advantageously some apertures of equipment or slit in casing wall, so that joint that can cooling collar inside.Strutting piece also comprises at least one jockey, so that described sleeve pipe each several part is combined.

This second embodiment and modification thereof preferably also comprise two linings, and they are used to be installed in each place, end of sleeve pipe, so that sleeve pipe is fixed on the cable.

Strutting piece is configured as a sleeve pipe or two one half-covering tubes with each lining, has a kind of advantage of strong especially strutting piece, and make the part of whole cable joint and every cable avoid external action basically.

Lining preferably is divided into two half linings on axially, so that help assembling.

The advantage that each lining has is that they can be made of the prefabricated standard lining that is used for the high and medium voltage cable.A kind of material commonly used is a rubber, and as ethylene-propylene rubber or silicon rubber, it allows that certain elasticity is arranged when keeping cable.From the thermal expansion aspect, this also is favourable.Lining allows to have certain expansion in cable, also allow when cable cools down and shrink, and carries out the oneself and adjusts.

According to a particularly advantageous embodiment, each lining equipment special device is used for absorbing because the cable dimension change that thermal expansion or contraction cause, this special device is some radial corrugation (no matter be in inside or externally) preferably.This has following advantage, the thermal expansion below promptly each lining can absorb in the cable insulation.

According to another characteristics, because strutting piece and annex thereof can be with a kind of electric conducting material manufacturings, thereby allow joint ground connection, so obtain a special advantage.In addition, if want to avoid ground connection, then strutting piece and annex thereof also can be with a kind of electrical insulating material manufacturings.

Various electric rotating machines have been designed for the voltage in the 6-30kV scope routinely, and it has been generally acknowledged that 30kV is a upper limit.This means that generally a generator must be connected on the power network through a transformer, and this transformer brings the voltage up to the voltage levvl of power network, that is is elevated in about 130-400kV scope.

The present invention at first plans to use for high pressure.High pressure is interpreted as average voltage above 10kV herein.According to the exemplary operation scope of a device of the present invention can be voltage from 36kV to 800kV.Secondly, the present invention plans for using in the described technical field that is lower than at voltage under the 36kV.

Owing to adopt the electric conductor of some High-Voltage Insulations, just so-called high-tension cable, this insulated electric conductor has the hard insulator that is similar to use in the cable that transmits electric power (as XLPE cable), so the voltage increase of motor can be arrived such level, so that it can be directly connected on the power network, and need not an intermediate transformer.Therefore, Chang Gui transformer can save.Yet, accomplish that an essential condition of this point is, each cable can engage in a kind of reliable mode, therefore, can realize with the present invention.

For a better understanding of the present invention, will explain two embodiment of the present invention with reference to accompanying drawing by example now, wherein:

Fig. 1 schematically illustrates a strutting piece according to first embodiment of the invention,

Fig. 2 schematically illustrates the cross section that has according to a used cable joint of Fig. 1,

Fig. 3 schematically illustrates the cross section according to a used cable joint of second embodiment,

Fig. 4 illustrates the embodiment according to the selection scheme of a thin portion in the strutting piece of Fig. 3,

Fig. 5 illustrates the embodiment according to second selection scheme of a thin portion in the strutting piece of Fig. 3,

Fig. 6 schematically illustrate strutting piece among Fig. 3 a kind of improvement project and

Fig. 7 illustrates the cross section that passes a high-tension cable, and device is specially adapted to this cable.

According to embodiment shown in Figure 1, strutting piece is got a kind of shape of yoke piece 1.This yoke piece has an elongated shape and terminates in end 3,4.The shape of yoke piece is suitable for the profile of cable joint, and it is used for supporting.In illustrated embodiment, the shape of yoke piece is fully according to the shape of cable joint.Yet, also may be to have only the inside of yoke piece to have the shape of respective cable joint, and the outside of yoke piece have certain other suitable shape, see it is simple shape as a kind of from the viewpoint of making.

Yoke piece preferably is added on the joint at the middle part, and its end 3,4 contacts with two cables 6,7, and this cable 6,7 engages by cable joint 9, as shown in Figure 2.For yoke piece being fixed on each cable, strutting piece also comprises a resilient clamping device 11,12 at each end place.This clamping device can be made up of around the belt of yoke piece and cable winding a rhizosphere, and perhaps it can be made up of a kind of cable binding or analog.

If strutting piece is wanted ground connection, then yoke piece is made with a kind of electric conducting material such as metal.In this case, clamping device also must be made with a kind of electric conducting material certainly.

Yet if require strutting piece not allow ground connection, the selected material of yoke piece and clamping device should be for example plastics of a kind of non-conducting material so.

Fig. 3 illustrates the second embodiment of the present invention.Strutting piece comprises a sleeve pipe 15 herein, and this sleeve pipe 15 preferably is assembled on this joint at the middle part around 16 assemblings of a cable joint.Utilize this cable joint with two cable splice.The shape of sleeve pipe adopts the shape of cable joint, and the internal diameter of its middle sleeve is adapted to the external diameter of cable joint.Each place, end at sleeve pipe is provided with a lining 21,22, and its main purpose is with this sleeve pipe location and fixing around every cable.

Each lining for example can be made of with the standard lining prefabricated high and medium voltage.A kind of material commonly used is a rubber, and as ethylene-propylene rubber or silicon rubber, this rubber allows certain elasticity when attached cable.See that from the thermal expansion aspect this is favourable.Lining allows in the cable a certain amount of expansion is arranged, and when cable cooled down and shrink, lining also oneself was adjusted.

Figure 4 and 5 illustrate two particularly advantageous embodiment modifications of lining.In both cases, the lining quilt in the axial direction in two.

Fig. 4 only illustrates half of lining.This half lining 24 is equipped with a semi-circular hole 25, is used to pass cable.Inner surface, that is ripple of getting groove 26 shapes of the surface of geared cable equipment, groove 26 is enough dark, when being assemblied on the cable with convenient lining, can make the thermal expansion in the following cable insulation of this lining absorption.

And half lining 28 shown in Figure 5 is equipped with a ripple on its outer surface, comprising each groove 30.Groove among these grooves and Fig. 4 is pressed the same manner and is formed, and has same function.Lining also is equipped with the centre bore 29 of a geared cable.The corrugated outer surface of lining is towards the inside of sleeve pipe.

Certainly, can the lining with ripple be set on the two at interior and outer surface, in the time can reckoning with that below cable insulation has high thermal expansion, these ripples may be favourable.

Fig. 6 illustrates the modification of second embodiment shown in Figure 3.Sleeve pipe is axially gone up each half sleeve pipe 40,41 by two and is constituted herein, and this two half-covering tube surrounds a cable joint, is used to engage two cables 45,46.Two each half sleeve pipes have than the embodiment with a complete cannula and are assembled to simpler advantage on the cable joint.This complete cannula must center on this joint sliding.Two each half sleeve pipes utilize a jockey 48 to lump together around junction, and this jockey 48 can be the form of certain resilient clamping device, as a cable binding.In illustrated embodiment, a jockey respectively is set and a jockey is set at the sleeve pipe middle part in each cannula tip.The quantity of jockey is selected on demand.Are being linings 50,51 by two each half each end places of the formed sleeve pipe of sleeve pipe, they are corresponding to each lining among Fig. 3.

As what especially fully illustrate in Fig. 6, strutting piece makes cable and cable joint, and the two keeps straight and inertia.

In addition, in second embodiment with each half-covering tube of a sleeve pipe or two, all parts can be used the electric conducting material manufacturing, so that can ground connection; Or the electricity consumption insulating material is made.This sleeve pipe also can be equipped some apertures or slit 53 in casing wall, so that help the cooling of joint.

At last, Fig. 7 illustrates the cross section that passes a high-tension cable 35, and this high-tension cable is specially adapted to the present invention.High-tension cable 35 comprises the twisted wire part (31) that many glue for example use copper (Cu) to make, and has a circular cross section.These strands twisted wire partly is configured in the center of high-tension cable.What surround these strands twisted wire part 31 is first semi-conductive layer 32, and what surround this first semi-conductive layer 32 is an insulating barrier 33, XLPE insulator for example, and what surround this insulating barrier 33 is second semi-conductive layer 34.Illustrated cable is with commonly used high-tension cable difference: earth shield of exterior mechanical formula and the metallic shield that is used for distribution around this cable saved usually.Therefore thought " high-tension cable " does not in this application need to comprise metallic shield or external ground shielding, and this metallic shield and earth shield are used for distribution around this cable usually.

Should regard some embodiment of diagram and explanation as just some examples, and the invention is not restricted to these examples, but can in the invention thought range described in dependent claims, change.Should point out emphatically, the invention is not restricted to various curved cables, but can be used for the cable joint that all types needs strutting piece.

Claims (24)

1. A device for cable splices of all kinds, especially on bent cables, said cable splice comprising two cables and a splice joint fitted between the cables in order to join them together , and the device also includes a support (1; 15; 40, 41) designed to fit over the joint so as to form the various parts of the joint (6, 7, 9; 16, 18, 19 ; 43, 45, 46) essentially remain stationary relative to each other, characterized in that it comprises at least one fixing member (11, 12; 21, 22; 50, 51), by means of which fixing member (11, 12; 21, 22; 50, 51) elastically fix the support to the cable, and said fixing member is capable of absorbing dimensional changes of the cable due to thermal expansion or contraction. 2. A device as claimed in claim 1, characterized in that, in a rotating electric machine, each cable is a winding, said winding being flexible and comprising: a conductive core; an insulating layer (33); and An outer semiconductive layer (34); the conductive core is surrounded by an inner semiconductive layer (32), an insulating layer (33) surrounds the inner semiconductive layer and consists of a hard material, and the outer semiconductive layer (34) surrounds The insulating layer, said layers are adhered to each other. 3. The device according to claim 2, characterized in that: said layers (32, 33, 34) are made of such materials, which have such elasticity, and between the thermal expansion coefficients of each material have such The relationship, namely: during operation, changes in volume in the layers caused by temperature fluctuations can be absorbed by the elasticity of the material, so that the layers maintain their mutual adhesion when temperature fluctuations occur during operation. 4. The device according to claim 3, characterized in that the material in said layers (32, 33, 34) is highly elastic, preferably with an E-modulus less than 500 MPa, preferably Has an E-modulus of less than 200 MPa. 5. A device as claimed in claim 3, characterized in that the coefficients of thermal expansion of the materials used for said layers (32, 33, 34) are of essentially the same order. 6. A device as claimed in claim 3, characterized in that the adhesion between the layers (32, 33, 34) is at least of the same order as the weakest of the materials. 7. A device as claimed in claim 2 or 3, characterized in that each of the semiconducting layers (32, 34) constitutes essentially an equipotential surface. 8. Device according to one of claims 2-7, characterized in that each cable (6, 7; 18, 19; 45, 46) consists of a high voltage cable (35). 9. The device according to claim 8, characterized in that the high voltage cable (35) has a diameter in the range of 20-250 mm and a conductive area in the range of 80-3000 mm ² . 10. Device according to any one of the preceding claims, characterized in that the fixing members (11, 12; 21, 22; 50, 51) are made of an elastic material. 11. The device according to any one of the preceding claims, characterized in that the support further comprises at least one rigid yoke (1); and the inner surface of said yoke, i.e. the surface facing the joint, is adapted to the joint external shape. 12. Apparatus as claimed in claim 11, characterized in that the support consists of three yokes, each yoke having essentially the same shape. 13. Device according to claim 11 or 12, characterized in that each yoke (1) has an elongated shape and ends in two ends (3, 4); said fixing means comprise A resilient clamping device (11, 12) to position and fix said yoke to the two connected cables (6, 7). 14. Device according to any one of claims 1-10, characterized in that the support comprises a sleeve (15). 15. The device according to claim 14, characterized in that the sleeve comprises two axial sleeve parts (40, 41); The parts come together. 16. Device as claimed in claim 14 or 15, characterized in that the sleeve (15; 40, 41) is equipped with some small holes or slits (53) in the sleeve wall, so that the inside of the sleeve The joint cools down. 17. A device as claimed in claim 14, 15 or 16, characterized in that the fixing member comprises two bushings (21, 22; 50, 51), one bushing mounted at each end of the sleeve , to secure the sleeve to the cable. 18. The apparatus of claim 14, wherein each bushing is divided into two axial bushing portions. 19. A device as claimed in claim 17 or 18, characterized in that each bushing is equipped with means for absorbing changes in the dimensions of the cable due to thermal expansion or contraction. 20. The device according to claim 17 or 18, characterized in that it comprises some radial corrugations (26) arranged on the inner surface of the bushing (24), i.e. facing on the side of the cable. 21. The device according to claim 17, 18 or 19, characterized in that said device comprises a radial corrugation (30) arranged on the outer surface of the bushing (24), also That is, on the side facing the inside of the sleeve. 22. Device according to any of the preceding claims, characterized in that the support (1; 11, 12, 15; 40, 41) is made of an electrically conductive material in order to provide grounding. 23. Device according to any of the preceding claims, characterized in that the support (1; 11, 12, 15; 40, 41) is made of a non-conductive material in order to provide insulation. 24. A rotating electrical machine comprising a stator and a rotor, the stator having windings drawn through slots of the stator, characterized in that it comprises a connector for various cables as claimed in any one of the preceding claims installation.

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