FR2555372A1 - FLEXIBLE JUNCTION FOR CONNECTING TWO HIGH VOLTAGE POWER CABLES - Google Patents

Abstract

THE FLEXIBLE JUNCTION FOR THE CONNECTION OF THESE CABLES 1, 2 WITH INSULATED CONDUCTORS KEEPED UNDER OIL PRESSURE IN A WATERPROOF SHEATH 13, 23 INCLUDES A CORRUGATED WALL ENVELOPE 3 SUBSTITUTING AROUND THE CONDUCTORS CONNECTED TO THE TERMINAL PORTION OF THE SHEATH CABLES AND, FOR THE CONNECTION OF EACH END OF THE ENCLOSURE ON ONE OF THE WATERPROOF SHEATHS, AN AUXILIARY FUR 55 IN WELDABLE MATERIAL ON THE WATERPROOF SHEATHS, CONNECTED, ON THE ONE HAND, TO THE ENVELOPE 3 BY AT LEAST A RING 40, 56 CROSSED BY FITTINGS WITH VALVE 41 AND, ON THE OTHER HAND, TO THE SEALED SHEATH 13 BY A WELDING CORD 60. APPLICATIONS: UNDERWATER ENERGY CABLES.

Description

Flexible connection junction of two high voltage power cables

  The present invention relates to a flexible junction for connecting two high-voltage power cables, in particular with lead or aluminum sheath for protecting the insulated conductors and

kept under oil pressure.

  High-voltage power cables are frequently made up of conductors insulated by paper ribbons impregnated with pressurized oil and protected by a tight sheath, generally made of lead or aluminum. This internal oil pressure is of the order of fifteen bars, for cables intended for laying at sea at depths of the order of a hundred meters, so as to come

  balance the bottom pressure to which the cable will be subjected.

  It is known to make a junction between two of these cables by a rigid metal case welded to the sheath of each of the cables, coming to surround the conductors of these cables, connected by soldering, on

  which has been restored to oil-impregnated paper insulation.

  Such a junction obviously does not allow subsequent winding, with a small radius of curvature, on existing drums or in the hold

  of a boat, of the resulting single cable.

  It is also known, by French patent n 1 002 522 in particular, to produce a flexible junction between telephone cables, by a cylindrical envelope with corrugated walls whose corrugations can be supported on resistant rings. Such a junction is

  intended to protect electrical equipment, such as amplifica-

  ters, repeaters-regenerators, necessary for proper operation

  of an undersea connection, which are interposed between two sections of cables and are connected to them. The ends of this envelope are mechanically and tightly connected to the corresponding ends of the two cable sections each equipped with a terminal piece carrying an insulating crossing terminal on

  which is stopped the internal conductor of the cable connected to the devices-

  lages. Taking into account the conditions of use, the envelope is filled with an incompressible insulating liquid capable of bringing the interior of this envelope in pressure equilibrium with that of the

  bottom to which the submarine link will be subjected. In this app

  cation, however, the sections of telephone cables were dry insulated, by polyethylene for example, for which there was no particular problem of internal pressure, the flexible junction having to simply ensure protection of the electrical equipment while making it possible to establish substantially a balance of

  pressure between the inside and the outside of the junction.

  The object of the present invention is to produce a flexible junction for connecting two high-voltage energy cables, with insulated conductors and maintained under oil pressure in a sealed sheath, using an envelope with corrugated walls of the above type and reconciling the problems due to the oil pressure to which the conductors are subjected and to the mechanical connection on the sections of cable whose conductors are connected by solder or crimped wire clamps. The subject of the present invention is a flexible junction for connecting two high-voltage energy cables, each with conductors mounted in a sealed sheath covered with an external armor, isolated and maintained under oil pressure, produced using an envelope with corrugated walls, characterized in that said envelope is mounted around the conductors of the cables and extends from

  on either side of their individual connection area is substituted for

  killing the sealed terminal portions of the sheaths of one and the other of the cables and that it comprises, for the connection of each of the ends of said casing to the corresponding incoming cable, an auxiliary fur, of material weldable on said sheaths , connected, on the one hand, by at least one ring traversed by valve fittings, to said casing which it extends around the tight sheath of the corresponding incoming cable and, on the other hand, by a connection weld bead sheathed

waterproof of this incoming cable.

  In a particular embodiment, the junction further comprises an intermediate fur of weldable material on said sealed sheaths, mounted on the end of the sealed sheath of each -3 - cables and secured by a weld bead d attachment not overhanging on its periphery, to this sealed sheath, receiving on its periphery at least said auxiliary fur with which said

  connection weld bead assembles it on said waterproof sheath.

  An exemplary embodiment of a flexible junction for connecting two high-voltage energy cables, according to the invention, is given in the attached drawing and described below with reference to the figures of this drawing. In this drawing: - FIGS. 1A and 1B schematize two energy cables connected by a junction, according to the invention, - FIG. 2 is a sectional view showing the connection of the junction, according to the invention, on the 'one of the cables shown uncut, - Figure 3 shows a method of connection between the

  armor of cables coming to cover said junction according to the invention.

  In FIGS. 1A and 1B, two high voltage energy cables 1 and 2 are very schematically illustrated connected by a flexible junction according to the invention. The cables shown are three-pole and each have three conductors insulated by paper tapes impregnated with oil under pressure, 10, 11 and 12 or 20, 21 and 22, maintained

  in a sealed sheath 13 or 23, made of lead or alternatively aluminum.

  Each of the cables 1 and 2 further comprises an external mechanical reinforcement armor, 14 or 24, formed of steel wires mounted at a wide winding pitch on an auxiliary sheath 15 or 25, or mattress, interposed between the steel wire armor and the lead tight sheath,

  for the protection of the latter.

  The actual junction is essentially formed by a cylindrical envelope with corrugated walls, 3, which will be connected to the lead sheaths 13 and 23 of the two cables, which it replaces around the conductors by forming a tight bellows transversely filled with oil under pressure. ; this envelope 3 is covered by the wires of the external armors 14 and 24 of the cables 1 and 2. For the

  description of this junction, we have located at 30 a central zone, at the

  level of which the conductors are connected and at 31 and 32 two zones known as the connection of the junction to one and the other of the cables - 4_ 1 and 2 respectively. We have also identified on both sides of the connection zones two zones 33 and 34 for adapting the profile of the

  cables, cooperating with the actual connection junction.

  In each of the cable profile adaptation zones, 33 and 34, frustoconical sleeves such as 16 and 26 are mounted on cables 1 and 2 respectively and as far as the corresponding connection zone 31 or 32, to gradually strengthen the diameter outside of each of the cables and thus adapt it gently to that of the junction itself. For the constitution of these profile adaptation zones, the external armourings 14 and 24 have been released over a sufficient length, either that the steel wires have been bent over the cable beyond this length or that they are abundant simply on

  this length, then pieced together on these sleeves and the junction.

  In the central zone 30, the conductors of each cable come out

  reassured by their waterproof sheath, 13 or 23 depending on the cable, are individually connected to those of the other cable, by soldering; for this operation the insulation tapes which covered the conductors individually were released for soldering and then reconstituted on

solder.

  The armours 14 and 24 of the two cables are also connected to each other in this central zone 30, using devices 35; an example of connection between these armors using

  of these devices 35 will be described below with reference to FIG. 3.

  The junction and its connection to one or other of the cables are described with reference to FIG. 2, in which the connection area 31 of the junction on the cable 1 and the parts has been illustrated.

  adjacent on either side of this zone 31.

  The connection of the junction is made on the waterproof sheath 13 of the cable 1, which has been sectioned just beyond the zone 31, to allow the individual connection of the stripped conductors of this cable to those of the other cable and then the reconstruction of their individual insulation. The auxiliary sheath 15 has also been sectioned, thus leaving bare the sealed lead sheath 13,

  practically along the length of this connection zone.

  The cylindrical envelope with corrugated walls 3, made of stainless steel for example, which extends at least over the length of the conductors

  stripped of their lead sheath is fitted with a metal ring-

  lique 40 welded, for example to the arc, or brazed, on the end of the casing 3 to be connected to the sheath 13. This ring 40 is equipped with at least one connection 41, with valve, crossing it and opening out in a circular groove 42 formed at the end of the ring, on the side of the envelope 3. This ring 40 has an inner diameter greater than the diameter of the sheath 13 so that it can be slid as far as possible with the envelope 3 on the sheath 13 (or the sheath 23 of the i0 8able 2), prior to the connection between the conductors of the two cables, to clear the operating field for this connection. A thin metallic fur 43 welded to the ring 40 is associated with the casing 3 to reinforce the welding of the ring 40 to the casing 3, while a metallic braid 44 is mounted around the casing 3, on its length to increase the resistance it must have to the internal oil pressure, while the final cable is not yet submerged. The ring 40 at the end of the envelope 3, furthermore has, on its face external to the envelope, a groove

  circular intended to receive a toroidal seal 45 in rubber.

  For the connection of the envelope 3 and end ring 40 assembly, an intermediate sleeve 50, solderable with tin on the sealed sheath 13 is slid over the end of this sheath 13. This intermediate sleeve 50 is for example made of bronze, or carobronze, and is welded to the sheath 13 by a first attachment weld bead 51. This weld bead 51 is produced on the end of this fur opposite to the end of the sheath 13, and does not

protrusion on the fur 50.

  This intermediate fur 50 is provided with a thickness substantially compensating for the difference between the diameter of the sheath and that inside of the ring 40 which can slide practically without

rubbing on it.

  An auxiliary filler 55 and a flange 56 are used to allow the connection of the corrugated casing 3 equipped with end sabague 40 on the sealed sheath 13, made of lead, itself equipped with

  the intermediate fur 50 which has just been welded to it.

  - 6 - This auxiliary fur 55, in bronze, is partially inserted in a circular recess formed internally at one end of the flange 56, chosen from nickel-plated and chromed copper; it extends widely on one side of the flange and is joined thereto by an outer circular weld bead 57 produced between it and the corresponding end of the flange. This auxiliary fur assembly 55 and flange 56 is secured to the ring 40, by bolts 59 screwed into the ring 40, through housings provided for their purpose in the flange 56 and forming a stop for their head, the auxiliary fur 55 s' then extending away from the envelope

  corrugated 3, on the flange 56 and the ring 40 which connect them mechanically

  only, the assembly being sealed by the toroidal seal 45

  then trapped in ring 40. -

  The auxiliary fur assembly 55 and flange 56 is, like the ring 40 at the end of the corrugated casing 3, of internal diameter

  substantially equal to the outside diameter of the intermediate fur

  diary 50, to be slid over the lead sheath 13 prior to the connection between the conductors of the cables, and to be brought back, with the ring 40 on which it is or is not previously fixed, on the intermediate liner 50. The ring 40, the flange 56 and fur

  auxiliary 55 are thus positioned along the intermediate fur

  diary 50, assembled together, these three pieces leave clear the first weld bead 51 and the corresponding end of the

  intermediate fur 50, on the side of the auxiliary fur 55.

  A second weld bead connecting to the tin 60 is produced between the lead sheath 13 and the auxiliary filler 55, for

  securing together the intermediate fur 50 and the auxiliary fur

  liaire 55 on this sheath 13. This second weld bead provides excellent connection of the auxiliary fur 55 on the sheath 13, it is also covered by a hoop 61 which reinforces it. This hoop, formed of copper wires wound in a helix with tight turns, extends from the end of the auxiliary sheath 15 of the cable 1 to the auxiliary fur 55 on which it is held; a stuffing 62, of varnished silk for example, fills the free weld gap on the lead sheath, between the auxiliary sheath 15 and the weld bead 60. A heat-shrinkable sheath 63, mounted on the hoop 61 and projecting on either side on the auxiliary sheath 15 and on the free part of the auxiliary fur 55, ensures the retention of the hoop 61 and the protection of the weld bead 61 against corrosion. After degassing of the junction connected identically on the two cables and filling it with oil, at suitable pressure, using the valve connector 41, the adaptation zones of the profile at the junction as illustrated are formed on each of the cables. in Figures 1A and 1B and as started in Figure 2 for the area

  corresponding profile adaptation.

  This profile adaptation zone is produced using

  frustoconical sleeves 16 placed end to end, mounted on the auxiliary sheath

  liaire 15 and the heat-shrinkable sheath 63 at the connection weld bead 60. They gradually adapt the outside diameter of the cable 1 to that of the corrugated casing 3 covered with its braid 44 of mechanical reinforcement. These sleeves are constituted by two half-sleeves joined and maintained on the auxiliary sheath 15 by hoops such as 66, or alternatively, joined by lateral screws and if necessary on the sheath 15 by hoops, in order to be able to be put in place once the junction is connected to the cable 1. The terminal sleeve, junction side, which extends over the connection area of the junction on the cable 1, has an interior profile adapted accordingly. This end sleeve mounted in abutment against the flange 56 has the ends of its bore which bear on one side on the corresponding end of the heat-shrinkable sleeve 63, and

  the other on the auxiliary sheath 15, beyond the heat-shrink sheath

  table 63. Its interior walls are machined, between its support ends, to define a sufficient recess at the connection weld bead 60, they leave a space 67, kept free or alternatively filled by a mattress, around the elements of

  protection 61, 63 of this connection weld bead.

  The external armor 14 of the cable 1 is connected to the external armor of the other cable, both brought back to the junction formed between these two cables after the adaptation of their profile to that of the junction has been performed, to complete this Junction, ensuring

its mechanical reinforcement.

  A method of connecting these armours, carried out by the dispo-

  35 in the central area 30 of the Junction (Figure 1A) is shown in Figure 3. In this Figure 3, the armor 14 and 24 of the cables are

  brought back onto the metallic braid 44 covering the corrugated envelope 3.

  The helically wound steel wires which make up these armours have been designated by 18 and 28. The connection device 35 is constituted by a threaded sleeve with reverse pitch on either side of its median part, receiving the ends of a thread 18 of the armor 14 and of a thread 28 of the armor 24 threaded not reverse from each other over a suitable length. Ports such as port 38 in the middle portion of each sleeve 35 allow the introduction of a

  tool for screwing the sleeve onto the two steel wires to be connected.

  In this FIG. 3, the connection sleeves 35 of each pair of wires are inclined to respect the angle of committing of the

  armor thread. They will be arranged according to a single provision annu-

  they can alternatively be arranged differently.

  The present invention has been described with reference to the example of

  illustrated realization; in practice we can make changes

  detail cations and / or replace certain means by other equivalent means without departing from the scope of the invention. This junction according to the invention also applies to the connection of two cables

monopolar energy.

- 9 -

Claims (8)

  1 / Flexible connection junction of two high-voltage energy cables, each with conductors mounted in a sealed sheath covered with an external armor, isolated and maintained under oil pressure, produced using an envelope corrugated walls, characterized in that said casing (3) is mounted around the conductors (10-12, 20-22) of the cables (1, 2) and extends on either side of their individual connection area by replacing the sectioned end portions of the tight sheaths (13, 23) of one and the other of the cables and which it comprises, for the connection of each of the ends of said envelope (3) on the corresponding incoming cable (1 ), an auxiliary fur (55), of material weldable on said sheaths, connected, on the one hand, by at least one ring (40, 56) traversed by valve fittings (41), to said casing (3) which '' it extends around the waterproof sheath of the incoming core-responding cable (1) and, on the other hand, by a weld bead ure   connection (60) to the waterproof sheath (13) of this incoming cable.   2 / flexible connection junction according to claim 1, character-   laughed at by the fact that it also comprises an intermediate fur   diary (50) of material weldable on said sealed sheaths, mounted on the end of the tight sheath of each of the cables and secured, by a hooking weld bead (51) not projecting on its periphery, to this sealed sheath, receiving on its periphery at least said auxiliary fur with which said weld bead   connection (60) assembles it on said sealed sheath (13).   3 / flexible connection junction according to one of claims 1 and   2, characterized in that it comprises a plurality of frustoconical sleeves (16, 26) mounted end to end around each connection weld bead (60) and the tight sheath (13) of the corresponding cable (1), gradually adapting the cable diameter   concerned with that of said envelope.   4 / flexible connection junction according to one of claims 1 to   3, characterized in that it is covered by the external armors (14, 24) of said cables, connected to each other by - 10 -   individual connection devices (35) between wires of said armor.   / Flexible connection junction according to one of claims 1 to   4, characterized in that it comprises a mechanical reinforcing band (61) mounted on each weld bead of connection (60).   6 / flexible connection junction according to claim 5, character-   laughed at by the fact that it comprises a heat-shrinkable sleeve (63)   covering said mechanical reinforcing band (61).   7 / flexible connection junction according to claim 1, characterized in that said auxiliary fur (55) is connected to the corrugated casing (3) by said ring (40) through   by the valve connections (41) and pre-welded at the corresponding end   dante of said envelope, and by a flange (56) pre-welded to said auxiliary fur 55) and fixed on said ring by clamping between   it and the ring a seal (45).   8 / flexible connection junction according to claim 7, characterized in that it comprises a braid of mechanical reinforcement (44) surrounding said envelope and, on each end of said envelope, a fur (43) of mechanical reinforcement of the   welding of said ring (40) on said envelope.   9 / flexible connection junction according to one of claims 7 and   8, characterized in that said ring (40) has a circular groove (42) open on the inside of said envelope (3), in   which open said valve fittings (41).