CN1009408B - Cable termination for paper-insulated three core medium voltage cables - Google Patents

Abstract

A cable termination for paper- insulated medium voltage cables, includes a multi-fingered termination sleeve fitting sealingly on the cable sheath and on exposed core end portions and enclosing an encapsulating resin which forms a solid insulating body surrounding a crotch area, and is sufficiently flexible in the core fingers to prevent the creation of gap- forming forces in the crotch area under the influence of movements of the core ends, the spreading of the core end portions in the crotch area being determined by a rigid spreading body interposed between the cores.

Description

Cable termination for paper-insulated three core medium voltage cables

The present invention relates to a kind of cable end of multi-core power cable.

In power cable head, in order to carry out desirable being electrically connected, the free end of cable core must have enough flexible.But when cable end assembling and operation, cable core ends is (for example owing to the moving that heating causes) that will move.And the geometry of cable end bifurcation region and sealing are unalterable.So it is difficult will making the cable end that satisfies actual engine request at the scene.

In the practical application now, a reliable solution to the cable end internal process is such, cable end is installed in one to be full of in the chest or box sealing resin, that sufficient mechanical strength is arranged, this technology is very expensive, and occupies bigger space according to the cable end of above technology made.

Now in the practical application, be, the bifurcation region of cable end put in the light plastic casing of a multilayer sleeve that this shell has not been held cable duct tube to cable core, and the bifurcated of definite cable to another solution of cable end internal process.Be full of sealing resin in this plastic casing, and cable end has been carried out necessary processing, made its mechanical strength reach requirement.Adopt this method, must use different plastic casings for the cable of different model.In addition, the resin of hardening has formed hard curved edge, and the cable core ends part is therefrom extended, and therefore, cable insulation may be damaged.

In addition, in the cable end known to everybody, its internal process is processed in addition as follows, and the flaky material shell of apparatus flexible replaces used hard shell, therefore the space occupied of cable end can be reduced widely, and also is simple to the cable end preprocessing at the scene.The present invention produces with regard to being based on this cable end.

The processing method of this cable end internal process is as follows: after the toughness sleeve pipe of cable end installs, inject the sealing resin of slow hardening in sleeve pipe.This sealing resin sclerosis is quite slow, so that the free end of time enough tie cable is arranged and the bifurcation region in the cable end is laid wedge on request.After the cable core ends connection was finished, cable core ends also had slight moving, and for example, what heating caused during installation moves.Cable end in the past, when they were installed, the expansion of cable core arranged and can't fix that it depends on the careful degree and the technical merit of installation personnel, up to hardening of resin, the moving of cable core termination that changes the layout of cable core just can not be taken place.

Cable end of the present invention is particularly suitable for the paper insulated power cable of medium voltate, and it can very successfully carry out the scene installation and can not encounter problems.Can put into operation immediately behind this manufacturing cable head, and its space of occupying is very little.

According to the cable end of this invention, each is fixed on its cable core on the hard wedge mutually reliably, thereby whether the staff of cable end manufacturer works carefully, with the installation quality of cable end be incoherent.In the installation of cable end or when putting into operation, the moving of cable core end, the power that does not form the gap can be sent to bifurcation region, because the finger ends of cable end sleeve pipe wraps on the cable core ends to toughness.Thereby cable core ends is partly anchylosed.In addition, the bifurcation region of cable core and near, the cable core sealing resin has bigger thick-layer, thereby constitutes a solid shape body.Therefore, cable core ends can reliably and be securely fixed on the wedge, can adopt the cable seal resin of quick-hardening, stube cable core end after the sclerosis, and then, this cable end can come into operation immediately.

The present invention will adopt for example and with some illustrated methods, carefully be described.Fig. 1 is the front view that a width of cloth is partly analysed and observe, and is an embodiment of cable end of the present invention.Fig. 2 is a width of cloth perspective view, and Fig. 1 is big for its ratio, and it is a wedge in the cable end in the present invention.Fig. 3 is the partial sectional view corresponding to Fig. 1, and it has expressed the sleeve pipe that is enclosed within on the cable core.Fig. 4 is the front view of a broken section, and it has expressed a movably cable core sleeve pipe.Fig. 5 is the partial sectional view corresponding to Fig. 1, the toughness sleeve pipe in the cable end that it has represented to make according to the present invention.Fig. 6 has represented the local cable end that has the toughness shrinkable sleeves corresponding to Fig. 1.

In Fig. 2 to Fig. 6, be marked with three bit digital corresponding to the parts of Fig. 1, two digits is same as in figure 1 thereafter, and that bit digital of foremost is consistent with figure number.Fig. 1 has represented the cable end of middle voltage, particularly the cable end of 7 to 18 kilovolts paper insulation three core power cables.Cable 1 has a cable packages layer 3 that is terminated at cable packages layer end 5, and in this embodiment, cable packages layer 3 includes a paper oil insulation layer 9, one wavy metal armor 11 of 7, one semi-conductive paper insulation layers and a plastic outer sheath 13.Cable 1 comprises paper insulated three-core cable, in the cable end of a disengaging encapsulated layer 3, the naked cable core end 15,17,19 that has paper insulation 21,23,25, they stretch out from bifurcation region 27, wherein wedge 29 is to embed between cable core, and enter 5 zones, cable packages layer end, thus entering bifurcation region 27, exposed cable core ends is fixed between wedge 29 and the cable jacket end 5.As can be seen, cable core top is paper insulated from illustrated example, in each cable core ends, has other core sleeve 31,33,35.In illustrated embodiment, these sleeve pipes are to be manufactured by the plastic material with lasting elasticity and toughness.Between the cable core sleeve pipe, there is certain mechanical elastic, if desired, may has the characteristic of elastic force control.In illustrated embodiment, cable core sleeve pipe 31,33,35, reach the zone of wedge 29, there, they are put on the convex shoulder 37 of wedge 29 with the adjacent cable end always, adopt this structure, after cable core sleeve pipe 31,33,35 was enclosed on the cable, wedge 29 preferably was introduced into, after the cable core sleeve pipe is placed, the convex shoulder 37 and the end interlock of adjacent cable core sleeve of wedge 29, thus seamless in the installation position.In illustrated embodiment, but cable core sleeve pipe 31,33 and 35 is (not the having expression among Fig. 1) that formed by elastic shrinkage by the sleeve pipe of elastic dilatation, the cable core sleeve pipe of this expansion has big size, so just is set on the cable core easily.

The sealing of cable core appearance is to make a glove-like with the material with lasting elasticity, toughness to refer to cable end sleeve pipe 39 more.Have cable core in the cable end sleeve pipe 39 and refer to 41,43,45, they place under mechanical elastic on the cable core sleeve pipe 31,33,35, also have a cable finger-like cover 47, and it places under mechanical elastic on the external jacket 13 of cable packages layer.One head 49 is arranged in the middle of the cable end sleeve pipe 39.Cable end sleeve pipe 39 is sleeve pipes of an expansion, and larger-size finger- like cover 41,43,45,47 is arranged on it, and cable sleeve moves to after-contraction on the cable end, and in bulbous region 49, the diameter of expanded casing is slightly bigger.In illustrated embodiment, expanded casing (in Fig. 1 not expression) is to support expansion in advance with mechanical supportive device, and then, mechanically moving bracing or strutting arrangement selectively is with the formation sleeve pipe.Bracing or strutting arrangement preferably includes a movably support helix spring.The sleeve pipe of this predilation made from mechanical system at american documentation literature the 3rd, 515, had description in 798, as a reference here.Before shrink sleeve and to the preliminary sealing of cable end sleeve pipe bottom, for example tie up after the lower end of cable end sleeve pipe by means of adhesive tape, be injected in the distensible cable end sleeve pipe 39 with curable sealing resin.Because the contraction of cable end sleeve pipe, sealing resin is pressed in the bulbous region 49, and because the injection of sealing resin not only makes insulating performance of cable be strengthened, but also make the slit that might exist be filled.In addition, cable core ends part 15,17,19 sealed insulation resins are sealed in the bulbous region 49, are fixed on the wedge.Wedge 29 is hard basically, comprising the material of hard polyethylene and so on.Cable end among the present invention by means of wedge 29 and the hard sealing resin outside wedge, has obtained a kind of structure of mechanically firm combining.

According to the structure of cable, the end portion 5 of cable packages layer 3 is carried out preprocessing.In described embodiment, cable external jacket 13 and metal armor 11 are approximately wanted split to illustrating graticule 53 places.The insulating paper (oil-immersed insulating paper) that protrudes is tied up with high-intensity insulating tape, and any unnecessary insulating paper should be torn off.

In illustrated embodiment, in bifurcation region 27, prevent from the expansion of cable packages layer end portion 5 to make the cable core fixation case obtain further improvement with a stiffener.In illustrated embodiment, described stiffener is to be made of the bundle 57 that can not extend.And high-intensity insulating cement belt 55 has also played the effect of a stiffener.

Fig. 2 represents a hard basically wedge 229, and it has the concave curved surface 59,61,63 that is used to guide out cable core.In addition, above the wedge 229 mentioned, comprise that is positioned at its end, leave the convex shoulder of having described 237 of the cable (Fig. 1) of mounting portion, on the installation site of cable, the interior extremity of cable core sleeve pipe 31,33,35 is installed on the convex shoulder 235 under the effect of mechanical pressure.

Fig. 3 represents the cable core sleeve pipe 331,333 tied up with the toughness insulating tape.When this embodiment can install at the scene, finish with very easy equipment.

Express among Fig. 4 under elastic expansion, a cable core sleeve pipe 431 can move along cable core 415 separately.In order to impel this moving, be processed into rib-like on the surface, inside of cable core sleeve pipe 431, sleeve pipe is only contacted in the part with cable core, make the relative motion between them more convenient.For paper insulated cable core, the inside of sleeve pipe is surperficial even can make irregular shape.

Fig. 5 represents with Fig. 1 corresponding, has the perspective view of part section, promptly makes cable core sleeve pipe 65,67,69 with distensible sleeve pipe, in this case, wedge also is not embedded into, with a bracing or strutting arrangement 71, can be fixed on the cable core with expanded casing through after mechanically expanding.In illustrated embodiment, each bracing or strutting arrangement comprises a support helix spring, and it links at cable abutting end (lower end among Fig. 5) and a tow attachment 73, and tow attachment extracts from the upper end of expanded casing.For the cable core sleeve pipe in the shop drawings 1 31,33,35, the sleeve pipe 65,67,69 of expansion is placed on the exposed cable core ends part 515,517,519, so that be suitable for wedge 29(Fig. 1) on the position of interlock, their cable abutting end is positioned on the same horizontal plane substantially, and has preferably carried out described preliminary treatment) near cable packages layer end 505(.In addition, the support helix spring can pull out with tow attachment.Cable core sleeve pipe the 31,33, the 35th among Fig. 1, expanded casing 65,67,69 shrink back formation.

Express a local cable end of installing among Fig. 6.In installation process, the same as previously described, cable core sleeve pipe 631,633,635 be placed to specify sentence after, wedge (not have among Fig. 6 to represent) can be with the following interlock mutually of its shoulder cable end piece adjacent with the cable core sleeve pipe.Then, wedge is embedded into suitable position artificially.In addition, the cable end sleeve pipe 75(front of a glove-like of being made by lasting elastomeric material is mentioned) be moved to cable end in being fixed to as shown in Figure 6 bifurcation region till.

The represented cable end sleeve pipe of Fig. 6 have three independently first sleeve portion 77,79,81 of finger-shaped to form cable core finger- like cover 41,43,45(Fig. 1) and corresponding second sleeve portion 83 of an opposite location to form cable finger-like cover 47, also have mid portion 85 formation ring-shaped areas 49.In each sleeve portion, mentioned a mechanical support device 87,89,91,93, they can be walked so that sleeve pipe shrinks by folding.In illustrated embodiment, each bracing or strutting arrangement has a support helix spring, and its tow attachment 95,97,99,101 stretches out from the interior extremity of support helix spring, and becomes driving element.When pine is drawn in the artificially and take out the support helix spring, make each sleeve portion elastic shrinkage.

In order to finish the installation of cable end, situation about representing from Fig. 6, link to each other with the cable available adhesive tape of end and 603 sealing of cable packages layer of resilient second sleeve portion 83 of the cable end sleeve pipe 75 of expansion, in addition, in order to keep perpendicular positioning shown in Figure 6 as far as possible, sealing resin is injected an opening of the cable sleeve first 77,79,81 of expansion.Have, the bracing or strutting arrangement 93 in the sleeve pipe second portion 83 can be removed with tow attachment 101 again.Therefore, sleeve pipe second portion 83 forms and shrinks Fig. 1 in the cable fingerstall 47(of cable packages layer end 605 tightly).The first 77,79,81 of last sleeve pipe forms cable core fingerstall 41,43,45(Fig. 1 with same method).After sleeve pipe first shrinks, sealing resin is added in the gap of all existence, and particularly in mid portion 85, bulbous region 49 whole sealed resins 51 promptly shown in Figure 1 are full of, there, the lasting elastomeric material that shrinks firmly and closely seals up the structure of its inside.

Claims (7)

1, the cable end of the power cable that has encapsulated layer (3) of a multicore comprises: one is positioned at the bifurcation region (27) that cable packages layer end (5) located, and extends exposed cable core end (15,17,19) from cable packages layer end; A multicore finger-like cable end sleeve pipe (39), cable end sleeve pipe have a finger-like cover on each cable core, and closely contact with cable packages layer (3) in cable core ends; Also be included in bifurcation region (27) and form the sealing resin (51) that insulate on every side, it is characterized in that, in bifurcation region (27), the hard wedge (29) that can determine the cable core expansion is placed between the cable core, wherein sealing resin (51) forms solid insulator, and cable end sleeve pipe (39) and cable core ends part (15,17,19) closely contact, cable end sleeve pipe (39) and be positioned at sealing resin layer between cable end sleeve pipe and cable core ends has enough toughness, and the cable core free end is moved easily, sealing resin layer wherein is thinner than the resin bed in the bifurcated zone 27, in cable end sleeve pipe (39), contains lasting elastomeric material, and elasticity is pressed on cable core end (15,17,19), and on cable packages layer (3) and the insulator.

2,, it is characterized in that wedge has the concave curved surface (59,61,63) that is used for to the cable core bifurcated according to the cable end of claim 1.

3, according to claim 1,2, it is characterized in that wedge (29,229) has a convex shoulder (37,237), be used for carrying cable core sleeve (31,33,35) the inner, this convex shoulder is positioned at the wedge end, and its installation site (Fig. 1) be cable dorsad.

4,, it is characterized in that wedge (29) wherein is snapped at its installation site (Fig. 1) according to claim 3.

5,, it is characterized in that in cable end sleeve pipe (39), forming a bulbous region (49) around bifurcation region 27 according to the cable end of claim 4.

6,, it is characterized in that having a finger-like cover (39) according to the cable end of claim 5.

7, according to claim 1,2, it is characterized in that having a cable end sleeve pipe (31,33,35,39) it by sleeve pipe (65,67,69 Fig. 5 of expansion; 75, Fig. 6) through shrink forming, this sleeve pipe by means of at least one bracing or strutting arrangement (71, Fig. 5; 93, Fig. 6) elastic dilatation is to big size, and this bracing or strutting arrangement is to constitute with a support helix spring, and this spring can be extracted out from the sleeve pipe of expansion, so that the sleeve pipe elastic shrinkage.

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