CA2174478A1 - Method of splicing cables and connectors for use therein - Google Patents
Method of splicing cables and connectors for use thereinInfo
- Publication number
- CA2174478A1 CA2174478A1 CA 2174478 CA2174478A CA2174478A1 CA 2174478 A1 CA2174478 A1 CA 2174478A1 CA 2174478 CA2174478 CA 2174478 CA 2174478 A CA2174478 A CA 2174478A CA 2174478 A1 CA2174478 A1 CA 2174478A1
- Authority
- CA
- Canada
- Prior art keywords
- connector
- protrusion
- depression
- cable
- connector part
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/28—Clamped connections, spring connections
- H01R4/30—Clamped connections, spring connections utilising a screw or nut clamping member
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- Cable Accessories (AREA)
Abstract
A pair of connector parts for use in splicing two PILC cables together, or a PILC
cable to an XLPE cable, each comprises a tubular socket portion at its one end and a solid contact portion at its other end. The contact portion is stepped to provide a medial contact surface. Fastening screws extend through aligned holes in the contact portions to clamp them together with their respective contact surfaces juxtaposed. Each contact surface has at least one protrusion and a complementary depression which are shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are juxtaposed. The protrusion and depression may be spaced apart along the length of the contact surface of the connector. The holes for the fastening screws, and the protrusion and depression may be aligned longitudinally with the protrusion and depression between the holes, or vice versa. Alternatively, the holes may pass through respective ones of the protrusion and depression, so the contact surface may be shorter. Alternatively, a single hole may be provided between the protrusion and depression to receive a single fastening screw.
cable to an XLPE cable, each comprises a tubular socket portion at its one end and a solid contact portion at its other end. The contact portion is stepped to provide a medial contact surface. Fastening screws extend through aligned holes in the contact portions to clamp them together with their respective contact surfaces juxtaposed. Each contact surface has at least one protrusion and a complementary depression which are shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are juxtaposed. The protrusion and depression may be spaced apart along the length of the contact surface of the connector. The holes for the fastening screws, and the protrusion and depression may be aligned longitudinally with the protrusion and depression between the holes, or vice versa. Alternatively, the holes may pass through respective ones of the protrusion and depression, so the contact surface may be shorter. Alternatively, a single hole may be provided between the protrusion and depression to receive a single fastening screw.
Description
BACKGROUND OF THE INVENTION
TECHNICAL FIELD
This invention relates to a method of splicing cables, especially high voltage electrical l ' ~l. ' cables, and to connectors for use in the method. The invention 5 is especially applicable to the joining of conductors in single and multiple conductor paper insulated lead covered (PILC) cable splices; crossed linked ~ (XLPE) cable splices; and also the joining of conductors in single and multiple conductor Ul- di..~ transition splices (PILC to XLPE).
Paper Insulated Lead Covered (PILC) cables have been used for, ', _ ' power l~ \ for d~ 90 years. The most commonly used type has three though single and four conductor varieties are also quite common. PILC
cable is most often installed in manhole and duct systems to feed overhead lines, large 15 buildings in the downtown core of large cities and also, ' ~,.. ' residential~' b~ systems. These cables are also quite often direct buried, as manhole and duct systems are very expensive to install. The most common voltage ratings of PILC
cables are the 5,000 volts and 15,000 volts with ampacity ratings ranging from 250 amps to 600 amps. A typical three conductor 500 mcm, 15 kV PILC cable, with an outer 20 sheath of lead, housing three oil ~ . " ' paper insulated 500 mcm conductors which are bound with multiple layers of belting paper, has an outside diameter of two and three quarter inches and weighs ~ , 13 pounds per foot. Such a cable is very difficult to hamdle manually, especially in the confined space of a manhole or, where the cable is buried, a dug hole. f . ~ splicing of such cables for repairs or re-25 cnnf,., ~ is difficult.
Cv..~.,..~..ally, when two PILC cables are being spliced together, the conductorsare joined using a split connector which is soldered in place by a process known in the industry as "sweating of, - . With the conductors positioned end-to-end, a sleeve having a C-shaped cross-section is clamped around the bared ends of the 30 . ' Using a first ladle, molten solder is poured over the installed split connector. The excess solder is caught by another ladle held below the connector. The pouring is repeated until the solder begins to cool and set, completely filling the conductor strands and the connector, at which time the splicer shapes the putty-like ~ ~17~478 solder with a small wiping cloth to give the connection a smooth surface. The molten solder is taken from a heated solder pot which maint~ins the solder at aL~ / 700degrees r-~
A .I;s~l~. ~ of this known process is that it produces toxic fumes, both from~ the molten solder and possibly from chemicals in the cable itself. When soldering thethe Cable Splicer must we ar an approved respirator mask to avoid breathing toxic lead fumes from the molten solder and exposure to PCDD's and PCDF's produced from the thermal breakdown of PCB's, if present in the oil in the cable. It is well ~'- ' that, if PCB's are subjected to i I ~ D between 450 degrees Celsius 10 and 700 degrees Celsius, toxic products are formed. ul.ru. i '~, most utilities do not have a record of cables with known PCB's so, when splicing older cables, the Cable Splicer must use a full face respirator as opposed to a half face respirator, which he would normally use for the filtering of lead fumes. These respirators are very , especially on hot days. Another dlDadv 1~ is that, although the 15 respirators might protect the Splicer, they do not prevent these toxins from entering the c ~lYill t, which is also a major concern.
Other diDadV ' ,, concern back strain injuries associated with lifting of the heavy solder pots (approx. 60 Ibs.) and lowering them into the manhole, and the potential for burns from the high t , , of the molten solder, especially given the 20 cramped space in which the Splicer usually works. Also, the process demands high quality of ~ To be done correctly, the preparing of the ends, the soldering of the ~ the applying of the insulating tapes and the wiping of the outer sleeverequire the cable splicer to have a great amount of skill and training.
With the aim of; ' , the need for solder pots, alternative splicing methods 25 are being developed, such as heat/cold shrink insulations and outer jacketing ~ 1, a~ 61y popular in the utility industry are crimped tubular connecting sleeves. The conductor ends to be joined are inserted into the connecting sleeves and secured by crimping the sleeve. Such unitary tubular connectors can be used with single conductor XLPl~ cable in view of the cable's flexibility, enabling the sleeve to be slid onto one 30 conductor and the other conductor flexed to foreshorten it and allow its end to be inserted into the other end of the sleeve. They are not suitable for PILC cable, however, because of physical constraints imposed by the confined space in which the splicing operation usually takes place, such as a manhole or a "direct buried" splicing pit. The , . . . . _ _ _ _ .
~ 217~7g conductors of a PILC cable are relatively inflexible and cannot easily be flexed to r. ~1l the conductor and insert its end into the sleeve on the other conductor. The problem is ~.~li ' where there are three ' as is usually the case with PILC cable, because they cannot easily be separated and the conductor sections exposed 5 by removal of the sheathing and belting are quite short. Also, the paper insulation could be damaged by bending.
Utilities which primarily use PILC cable have been ~..~ where possible, to cross-linked pul~ alyl~n~ (XLPE) cable, espccially in new ' "~ Oll inct~ll and when replacing faulted seetions of " ' PILC cable. As a result, there is 10 sometimes a need to connect XLPE cable to PILC cable.
The invention also addresses problems which arise when crossed linked p~ l.yl~.lc (XLPE) cable is spliced to PILC cable. XLPE cable, along with its splicing and; ~ products, was introduccd some thirty years ago and is becoming more widely acceptcd in the utility industry. XLPE cable has an outer jaeket, made of PVC, 15 a concentric neutral for grounding purposes, a shielding layer of semi-conducting plastics material for relieving electrical stresses, an insulation layer and a conductor. Cable sizes vary, with the most widely used being single conductor 1/0 AWG and 500 mcm in the 5,000 and 15,000 volt ranges. The outer jacket, semi-conducting shielding layer and insulation layers are rubber based and the diameter of a single conductor 500 mcm XLPE
20 is about one and a quarter inches, so the cable is much lighter than PILC cable and easier to handle. Although three conductor XLPE cable is available, it is more common to use three single-conductor XLPE cables.
Splicing of PILC cable to XLPE cable presents problems beeause most PILC
cable is i~ O ' with a low viscosity oil. If this oil is not contained when splicing 25 PILC cable to XLPE cable and the oil migrates into the XLPE cable, ~ of the rubber ~ will take place over time and eventually the joint will fail. The problem of confining the oil occurs because oil pressures of over 100 psi can develop in long downhill lengths of cable, frequently causing outer lead sleeves to swell and split open, creating cable faults irl wet ~ll.;l~ Where there is such an increase of 30 pressure in a sealed run of cable, a vacuum is created in other ar~as where, if the seal is not strong, water may be drawn into the cable. To overcome these problems, ~ .~ have developed special splicing kits for splicing PILC cable to XLPE
cable. These splicing kits include extensive oil sealing devices including mastics, special ~ 2~74478 oil barrier tubings, high pressure tapes, break-out boots and oil block connectors (sleeve and solder types). C~ " the making and breaking down of a transition splice is especially ~ lt ' and costly.
Utilities replace cables as they fail, or for ~c ~ of the system for new 5 customers andlor loading purposes, so breaking down or taking apart of existing splices is quite common. Breaking down of PILC to PILC and XLPE to PILC splices is very labour intensive, messy and time . ~, For example, where a crimped tubular connector is used, it must be cut off and a new tubular connector installed. The oil seal must be broken and remade and cable cutbacks adjusted. Tbis cam result in prolonged 10 power outages, or prolonged reliance upon back-up supplies while cable faults are being repairedl and, for even routine splicing, incrcased iabour costs. There is also an increased risk of oil leakage and ~
There still remains, therefore, a ne~d for an effective alternative to soldered split connectors for joining PILC cables, and unitary, The present invention seeks to eliminate, or at least mitigate, the JiD~Iv of the above-described known connection techniques and has for its object to provide a new method of splicing such cables which does not require the use of molten solder.
Another object is to provide a connector suitable for use in such method.
20 SUMMARY OF THE INVENTION:
According to a first aspcct of the present invention, a comnector ~ for use in connecting end-to-end opposed conductors of power cables comprises a p~ur of connector parts, each connector part comprising at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being steppcd to provide 25 a medial contact surface, and fastcning means for clamping the two connector parts laterally together with their respective said contact surfaces jll-tqroC~l cach contact surface having at least one protrusion and . ' y depression shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are 30 juxtaposed.
Preferably, the connector socket portion is cylindrical and the contact portion serni-cylindrical. The contact surface may then be generally ~" ' Such a connector ~ may be used to join conductors of PILC cable ~ 2t'~478 without using molten solder. Col.v. ~ 'y, each connector part is slid onto the exposed end of the respective conductor and, the connector pa~;ts are juxtaposed and fastened together. The tubular portions are crimped onto the respective conductor ends.
According to a second aspect of the present invention, there is provided a method 5 of splicing together two paper insulated lead-covered cables using two coul ~
connector parts and fastening means, each connector part . , ~ at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being stepped to provide a media'l contact surface, the contact surface having at least one protrusion and .--ll' y depression shaped and positioned so that the protrusion 10 of one connector pa~;t engages the depression of the other connector part to a'lign the connector pa~;ts when the contact surfaces are; , 1, the method including the steps of:
~ " two conductors to be spliced with their respective end portions stripped of insulaaon;
securing the end portions of the conductors in respective socket portions of twoof said connector parts;
aligning the connector pa~;ts with the protrusion and depression of one connector engaging the depression and protrusion, ~ ~iiv~l~, of the otner connector; amd applying fastening means to clamp the connectors laterally together with their 20 respective contact surfaces in contact.
According to a third aspect of the present invention, there is provided a methodof splicing a plurality of cross-linked ~,ol~7 Lllyl~ (XLPE) cables to a paper insulated lead covered (PILC) cable having a c~ ., plurality of condu~orc using a plura'lity of ~urs Of C~ -r '~ C~ connector parts and fastening means, each connector part ~ ~ E. at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being stepped to provide a media'l contact surface, the contact su;face having at least one protrusion and c~r' y depression shaped and positioned so that the protrusiûn of one connector part engages the depression of the other connector part to a'lign the connector parts when the contact surfaces are30 jllY~nrnc.o,i the method comprising the steps of:
removing an outer sheath and belting from the PILC cable and separating its removing insulation from each conductor of the PILC cable to expose an end ~ 4478 portion;
installing an oil barrier tube on each conductor, the tube e~tending between theexposed end portion and the point at which the conductors separate;
installing a first break-out boot at the point of separation of the conductors of the S PILC cable;
installing a second break-out boot upon the three XLPE cables at a prescribed distance from the splice;
preparing the end portion of each of the XLPE cables and pigtailing its concentric neutral wires;
securing bared ends of the PILC conductors and XLPE cables into respective sockets of a plurality of pairs of said connector parts and fastening the parts of each pair together;
creating an oil seal between each oil barrier tube and the associated connector part;
installing insulating and shielding material over each pair of mated connector parts and sealing the material to said oil barrier tubing at one end and, at its other end, to insulation of the Wll~ V XLPE cable;
sealing between the first break-out boot and each oil barrier tube, the sheath of the PILC cable and each oil barrier tube and the sheath of the PILC cable;
connecting the pigtailed neutral wires to the sheath of the PILC cable; and installing an outer sleeve sealing at its one end to the first break-out boot and at its other end to the second break-out boot.
Various other features, objects and advantages of the present invention will become apparent from the following tl~crnrti~n taken in . ;. with the 25 a~ y;..~5 drawings, of u...~"' of the invention, which are described by way of example only.
BRIEF DESCRIPTION OF DRAWINGS:
Figure I illustrates PILC splices in a typical splicing bay of a manhole;
Figure 2 is a view of the manhole from above;
Figures 3a to 3g illustrate steps in the splicing of two paper-insulated covered(PILC) cables;
Figure 4a is a side view of a two-part separable connector showing the two parts ~ ~ 7~47g separated;
Figure 4b shows their contact surfaces;
Figures 5a to 5h illustrate steps in the splicing of a PILC cable to a XLPE cable;
Figures 6a and 6b illustrate a first ,. ~ of the connector contact portions;
5 and Figure 7 illustrates a second - ' ~
DESCRIPTION OF PREFERRED EMBODIMENTS
Figure I shows three PILC cables 10A, l l A and 12A entering a splicing bay 13, 10 typically in a small congested manhole, by way of a duct bank 15. For ~u,.v. ~
only three cables are shown, though there could be more or fewer. Three more PILC
cables 10B, llB and 12B enter by way of a second duct bank 14 at the opposite side of the splicing bay. Cu". r ' g pairs of cable 10A/lOB, llA/llB and 12A/12B are ~ , ' by cable splices 10C, llC and 12C, I~D~ . The splices 10C, llC
15 and 12C are mounted to one wall of the manhole by spaced supports 16A and 16B. As shown in Figure 2, splices 17C are mounted in like manner on the opposite wall and ~ similar p~urs of PILC caoles 17A and 17B.
Each PILC cable comprises three conductors which, in cross-section, each comprise an equal sector of a circle. Each conductor comprises a plurality of copper 20 strands and is wrapped with oil ~ . O ' paper insulation. The three wrapped conductors are surrounded by paper belting and encased in a lead sheath.
Splicing of two of the PILC cables 10A and 10B using the connector;
and procedure according to the present invention will now be described with reference to Figures 3a to 4b, it being d~l~JII ' ' ~ that the other pairs of cables will be spliced in 25 a similar manner and could, in fact, have been spliced previously and be in service. For ~iUll~ e~ CUII~ -- r ' of the cables 10A and 10B have the same reference numbers, but with the suffix A or B as d~JlnUl ' ' The end portions of two PILC cables 10A and 10B protruding into the splicing bay are overlapped as shown in Figure 3a, and lines 20A and 20B marked on cable 10A
30 and 10B, ~ , at the middle of the overlap. At this stage, cable 10B is cut atthe mark 20B. Cable 10A, however, is cut at a position one inch back of the mark 20A.
This dimension of one inch Wll~ r ~ to one half of a distanco Y (Figure 4a) which will separate the ends of the two conductors when spliced and butted up against interior ~ ~17~7~
end faces SlA/51B (Figure 4a) of sockets in their respective illt~
as will be described later. The PVC jacket 22A/22B and the lead sheath 24A/24B are removed from the respective end portions exposing the outer belting 26A and 26B for a specif~ed length as shown in Figure 3b. An outer lead sleeve (not shown) is preparcd 5 and installed over the end of one of the cables and placed down the cable ready for jnc~l1~nn later in the spicing process. The outer belting papers 26A of cable lOA are removed and the insulated conductors 28A, 30A and 32A of cable lOA are separated as shown in Figure 3c. The insulation is stripped to leave bare conductor end portions 34A, 36A and 38A, ~~livt;ly. The outer belting of cable IOB also is removed and 10 its conductors 28B, 30B and 32B separatPd, but the conductor end portions are not stripped of insulation at this time.
The length of each of the barPd end portions 34A, 36A and 38A ~w-~ ,olld, to that of a socket 40A in a socket portion 42A of a two-part separable connector, shown in Figure 4a. The cable splicer then installs a connector part 42A onto each of the barPd 15 ends 34A, 36A and 38A (see Figure 3d).
The connector parts 42A and 42B are identical, so only connector part 42A will be described in detail. As shown in Figure 4a, connector part 42A comprises a cylindrical socket portion 44A having a cylindrical hole 40A extending into it from one end. A solid contact portion 46A protrudes from the other end. The solid contact20 portion 46A is semi-cylindrical in shape and provides a ii~rnPrri~ily extending contact surface 48A extending from the end of the socket portion 44A to a radially extending shoulder 50A. Two holes 52A and 54A extend L~ v~.x;ly through the solid portion 46A and are centered on the cylindrical axis X-X (Figure 4b). When the two connector parts 42A and 42B are matPd with their respective contact surfaces 48A and 48B
25 abutting, fastening screws 56A and 56B extend through the holes and clamp the parts together. Hole 52A has a I ~,u,~; 58A to receive the head of screw 56A and hole 54A is 7.,.~n~ dded to receive the threaded shank of the other screw 56B.
Between the holes 52A and 54A, the contact surface 48A has a pair of ~ fi~rn~ n~, specifically a I , ' ' recess 62A and a ~ , ' y 30 protrusion 64A, disposed on the cylindrical axis X-X. When the two connector parts 42A and 42B are juxtaposed with their respective contact surfaces 48A and 48B incontact and their shoulders 50A and 50B in intimate contact with the ends 106B and 106A, l~i"J~ ,ly, as will be described later, the L~ 64A and 64B engage in the recesses 62B and 62A, ~- ~e ~ivc;ly, to locate the two parts 42A and 42B correctly and align the holes 52A and 54A with holes 54B and 52B, ~ ly, for insertion of the screws 56A and 56B.
Referring to Figure 3d, ensuring that the bared conductor ends 34A, 36A and 5 38A of cable lOA are fully seated in the sockets 40A of tbeir respective connector parts 42A, the splicer crimps the cylindrical socket portions of the connector parts to secure them to the conductor ends. For purposes of illustration only, in Figures 3d to 3g, the comnector part on the middle conductor 30A is shown rotated through 90 degrees relative to the other two connector parts.
As shown in Figure 3e, the splicer positions the conductors 28B, 30B and 32B
of cable lOB alongside the ends of the installed connector parts 42A marks each of the conductors of cable lOB at a position which is back from the end 106A of the ~Ulll r ~- ~ connector part 42A by a distance equal to the spacing between the shoulder SOB and socket interior end face SlB of connector part 42B (Figure 4a), and 15 cuts off the conductors 28B, 30B and 32B at this mark. The splicer removes the paper insulation to leave bare end portions and installs connector parts 42B on them also, as shown in Figure 3f, ensuring, as before, that the conductor ends are fully seated into the respective sockets.
The splicer aligns the mating contact surfaces 48A and 48B of each pair of 20 connector parts 42A/42B and ensures that all three pairs of connector parts line up before crimping the connector parts 42B to the respective conductors of cable lOB. If there is enough room to crimp the connectors in the splicing bay, the splicer can install and tighten the fastening screws 56A/56B before crimping the second set of connector parts.
If the splicing bay is congested, however, and it is difficult to get the crimping tool head 25 onto the connector parts, the splicer may carefully move the cable ends into a clear area, crimp the connector parts, reposition the cable ends in the splicing bay, realign the connector parts and then install and tighten the fastening screws.
Following insertion of the fastening screws (Figures 3g), the spliced conductors are re-insulated by applying insulating tape, squeezed together again and outer belting 30 applied. The outer lead sleeve is slid into place over the splice and its ends beaten down to the diameter of the cable. The outer lead sleeve is solder-wiped, and insulating compound poured into filling holes in the lead sleeve to fill and seal it. The filling holes are then sealed with solder.
~ 2174~8 Application of the invention to the splicing of a three-conductor PILC cable to three, single-conductor XLPE cables will now be described with reference to Figures 5a to 5h.
I~e XLPE cable can be flexed during ~ " l, so it should be notP~d that, as S will become apparent from the following dPc~rir~l~n~ the advantages of using the separable connector for splicing PILC cable to XLPE cable are realised when taking the splice apar~, as opposed to the initial making of the splice.
Referring to Figure Sa and Sb, the PILC end of the cable is prepared as it wouldbe for a PILC to PILC splice. As mentioned earlier, . of the oil to the PILC
10 end is critical. As shown in Figure Sa, oil barrier tubings 62/1, 62/2 and 62/3 are installed over the conductors 28B, 30B and 32B, ~ ly, with an oil seal to be made later at the connector part area. A "break-out" boot 60 (Figure Sb) is installed in the break-out area of the PILC cable, i.e. the point at which the conductors 28B, 30B
and 32B separate. The break-out boot 60 comprises a larger tubular portion at one end 15 fitting closely around the lead sheath 24B and three smaller tubular finger portions 64/1, 64/2 and 64/3 at its other end fitting closely about respective ones of the oil barrier tubes 62/1, 62/2 and 62/3. The breakout boot 60 is filled with either a mastic or resin compound to seal the break out boot 60 to the various parts embraced by it, namely the oil barrier tubes 62/1, 62/2 and 62/3, lead sheath 24B and any exposed belting 26B
20 effectively creating an oil seal in the conductor break-out area of the cable.
Referring to Figures 5c and 5d, the three XLPE cables 66/1, 66/2 and 66/3 are prepared by first removing the PVC outer jacket 68/1, 68/2 and 68/3 to a specified point. Their concentric neutral wires 70/1, 70/2 and 70/3 are pigtailed and drawn back for later bonding to the lead sheath 24B of the PILC cable. The semi-conductive 25 shielding layers 72/1, 72/2 and 72/3 are removed to a specified point and the conductor insulation 74/1, 74/2 and 74/3 removed to leave bare end portions 76/1, 76/2 and 76/3 to accept the connector parts 42A/1, 42A/2 and 42A/3.
A break-out boot 78 is slid onto the three single XLPE cables, each cable in oneof three fingers 80/1, 80/2 and 80/3 of the break-out boot 78. Multilayer 30 insulating/shielding tubes 82/1, 82/2 and 82/3 are then slid onto each of the three XLPE
cables. An outer jacket 84 (see Figure 5h) is slid over the PILC cable end (or over the XLPE cables) and placed down the cable ready for application later in the splicing process. (If a wrap-around jacket is used, it need not be installed at this point). Also, ~- 2~7k~78 a set of separate insulating and shielding tubes could be used instead of each of the mulalayer tubes.
Referring to Figure Sd, three p~urs of ~parable connector parts 42A/l and 42B/lB, 42A/2 and 42B/B, and 42A/3 and 42B/3 are fastened together and crimped onto 5 the respective PILC conductor ends, ensuring that the conductors are fully seated into the bore of the connector. Because the XLPE cables are more flexible than PILC cables, and separate, each of the single conductor XLPE cables can be flexed to insert its end into the open end of the ~O~ connector part, which is then crimped. After the connectors are installed, the oil-stop process is completed on the PILC end of the 10 connector. As shown in Figures Se and Sf, this involves applying either mastic tape or high pressure tape to form a seal 86 between the crimped portions of connector part 42B
and the oil barrier tube 62. The splice is then ready for rc ~ ' ~
The insulating/shielding tubes 82/1, 82/2 and 82/3 are slid into place over the connectors and shrunk down over the oil barrier tubes 62/1, 62/2 and 62/3 at one end 15 and the insulation 74/1, 74/2 and 74/3 at the other end. The pigtailed neutral wires 70/1, 70/2 and 70/3 are brought across the splice from the XLPE end cable and bonded to the lead sheath 24B. The break-out boot 78 is shrunk into place to bond to the three XLPE cables, as shown in Figure Sg. As shown in Figure 5h, the outer jacket 84 is installed to completely cover the splice and bonded at one end to the boot 78 and at the 20 other end to the PVC jacket of the PILC cable, to seal against moisture ingress.
An advantage of the present invention is that, when cable ., ~ is necessar~v and involves splicing into such an existing PILC to XLPE cable splice, it is possible to take apart the outer jacket 84 and shielding and insulating . , 82/1, 82/2 and 82/3, and unfasten the connectors 42A/42B without disturbing the cable 25 cutbacks and oil stop devices. New connector parts 42A crimped onto the ends of the conductors of the new cable are fastened to the mating connector parts 42B of the existing cable and the insulation, shielding and outer jacket restored. This is especially a~ ~ when the PILC cable is to be put back into service. By contrast, previously known PILC to XLPE splices using crimped one-piece connecting sleeves30 must be completely broken down, the crimped connecting sleeve cut out, the cable cutbacks must be adjusted and the oil . ,~ Not having to break down the oil ~ r- - and/or adjust cable cutbacks saves a lot of work and decreases recover,v time and costs.
74~78 The connector according to the present invention could also be used for single conductor in-line XLPE and PILC splices. If a section of cable had to be replaced between cable splices, use of the separable connector in the original splice would a.l.. ~ 'y avoid re-adjustment of the cable cutbacks, thereby reducing down-time5 and expenses, and would maintain the splice in its original position in the splicing bay.
The design of the mating contact surfaces 48A/48B of the separable connector parts 42Al42B is such that intimate contact after the fastener is tightened is ''~1 assured. The distance d (Figure 4b) between the centre of protrusion 64A and surface 50A is the same as the distance between the centre of depression 62B and the end 106B
10 of the coMector part. Hence, the contact portions are h~.1.~1.1, " so the connector parts may be identical. The curvature and positioning of the depression/protrusion aids in the alignment of the parts in all directions when mated, which allows for easy insertion of the fastening screws 56Al56B into their holes, and the intimate contact between the end faces 106AIB and shoulders SOBIA. When assembled, the separable 15 connector parts form a low profile, cylindrical connector which provides a smooth contour for the applying of insulating materials.
Various rn~Ylifi~hnne to the above-described ' ' are possible without departing from the scope of the present invention.
A ~Irst ,~ is illustrated in Figures 6a and 6b. The connector parts 20 comprise cylindrical socket portions 44A and 44B as before, but their solid, mating contact portions 46A' and 46B' differ from those of the connector parts of the first In particular, the holes 52A and 52B are concentric with the l , ~ 1 ~lVLI~ ' 64A and 64B and the holes 54A and 54B are concentric with tbe y ~ - 62A and 62B, l~Liv~ly. C~ the length of the 25 mating contact surfaces 48A and 48B is shorter, which further facilitates "
especially in confined spaces.
Figure 7 shows another m~lif ~h'on which results in a shorter overall connector length. In this case, a single fastening bolt 56 extends through a hole 54 between the protrusion and depression and receives a hexagonal nut 88. In this case, instead of a 30 . ' Ci, the moutb 86 of hole 54 is hexagonal to conform to the hexagonal nut 88 and hold it as the bolt 56 is tightened. It should be noted that the two connector parts are still identical.
The separable connector parts may be provided in various diarneters to fit various ~ ~174~78 sizes of c~ rf<-r.e Instead of crimping, the connector parts may be attached to the conductors by other means, such as clamping screws. Although the above-described~ ho.~ - have only one protrusion and one . ,' y depression on each contact portion, it would be possible to have more. For example, a duplicate set of holes 5 52A and 54A, protrusion 64A and depression 62A could be provided alongside the first set. It is also envisaged that, whereas the described i ' ' has the protrusion and depression between the screw holes, the holes could be between the protrusion and depreesion instead. ~ ,' ' protrusions and .L,~ are preferred because they result in more uniform electrical stress and fewer "hot spots" as compared with 10 contours having points or edges.
The connector patts and fastening screws may be made of any material which conforms to the standards and regulations of the industry.
An advamtage of the connectors of the present invention is that, since the two connector parts may be identical, ~ -~nnne and stocking costs may be reduced.
Although only the splicing of PILC and XLPE cables has been described herein, it should be a~ ' that the invention is also applicable to other kinds of power cables. Likewise, the invention applies to cables having voltage and current ratings other than those specified herein and which use different materials.
Although ~mho~ ntc of the invention have been described and illustrated in 20 detail, it is to be clearly understood that the same are by way of illustration and example only and not to be taken by way of the limitation, the spirit and scope of the present invention being limited only by the appended claims.
TECHNICAL FIELD
This invention relates to a method of splicing cables, especially high voltage electrical l ' ~l. ' cables, and to connectors for use in the method. The invention 5 is especially applicable to the joining of conductors in single and multiple conductor paper insulated lead covered (PILC) cable splices; crossed linked ~ (XLPE) cable splices; and also the joining of conductors in single and multiple conductor Ul- di..~ transition splices (PILC to XLPE).
Paper Insulated Lead Covered (PILC) cables have been used for, ', _ ' power l~ \ for d~ 90 years. The most commonly used type has three though single and four conductor varieties are also quite common. PILC
cable is most often installed in manhole and duct systems to feed overhead lines, large 15 buildings in the downtown core of large cities and also, ' ~,.. ' residential~' b~ systems. These cables are also quite often direct buried, as manhole and duct systems are very expensive to install. The most common voltage ratings of PILC
cables are the 5,000 volts and 15,000 volts with ampacity ratings ranging from 250 amps to 600 amps. A typical three conductor 500 mcm, 15 kV PILC cable, with an outer 20 sheath of lead, housing three oil ~ . " ' paper insulated 500 mcm conductors which are bound with multiple layers of belting paper, has an outside diameter of two and three quarter inches and weighs ~ , 13 pounds per foot. Such a cable is very difficult to hamdle manually, especially in the confined space of a manhole or, where the cable is buried, a dug hole. f . ~ splicing of such cables for repairs or re-25 cnnf,., ~ is difficult.
Cv..~.,..~..ally, when two PILC cables are being spliced together, the conductorsare joined using a split connector which is soldered in place by a process known in the industry as "sweating of, - . With the conductors positioned end-to-end, a sleeve having a C-shaped cross-section is clamped around the bared ends of the 30 . ' Using a first ladle, molten solder is poured over the installed split connector. The excess solder is caught by another ladle held below the connector. The pouring is repeated until the solder begins to cool and set, completely filling the conductor strands and the connector, at which time the splicer shapes the putty-like ~ ~17~478 solder with a small wiping cloth to give the connection a smooth surface. The molten solder is taken from a heated solder pot which maint~ins the solder at aL~ / 700degrees r-~
A .I;s~l~. ~ of this known process is that it produces toxic fumes, both from~ the molten solder and possibly from chemicals in the cable itself. When soldering thethe Cable Splicer must we ar an approved respirator mask to avoid breathing toxic lead fumes from the molten solder and exposure to PCDD's and PCDF's produced from the thermal breakdown of PCB's, if present in the oil in the cable. It is well ~'- ' that, if PCB's are subjected to i I ~ D between 450 degrees Celsius 10 and 700 degrees Celsius, toxic products are formed. ul.ru. i '~, most utilities do not have a record of cables with known PCB's so, when splicing older cables, the Cable Splicer must use a full face respirator as opposed to a half face respirator, which he would normally use for the filtering of lead fumes. These respirators are very , especially on hot days. Another dlDadv 1~ is that, although the 15 respirators might protect the Splicer, they do not prevent these toxins from entering the c ~lYill t, which is also a major concern.
Other diDadV ' ,, concern back strain injuries associated with lifting of the heavy solder pots (approx. 60 Ibs.) and lowering them into the manhole, and the potential for burns from the high t , , of the molten solder, especially given the 20 cramped space in which the Splicer usually works. Also, the process demands high quality of ~ To be done correctly, the preparing of the ends, the soldering of the ~ the applying of the insulating tapes and the wiping of the outer sleeverequire the cable splicer to have a great amount of skill and training.
With the aim of; ' , the need for solder pots, alternative splicing methods 25 are being developed, such as heat/cold shrink insulations and outer jacketing ~ 1, a~ 61y popular in the utility industry are crimped tubular connecting sleeves. The conductor ends to be joined are inserted into the connecting sleeves and secured by crimping the sleeve. Such unitary tubular connectors can be used with single conductor XLPl~ cable in view of the cable's flexibility, enabling the sleeve to be slid onto one 30 conductor and the other conductor flexed to foreshorten it and allow its end to be inserted into the other end of the sleeve. They are not suitable for PILC cable, however, because of physical constraints imposed by the confined space in which the splicing operation usually takes place, such as a manhole or a "direct buried" splicing pit. The , . . . . _ _ _ _ .
~ 217~7g conductors of a PILC cable are relatively inflexible and cannot easily be flexed to r. ~1l the conductor and insert its end into the sleeve on the other conductor. The problem is ~.~li ' where there are three ' as is usually the case with PILC cable, because they cannot easily be separated and the conductor sections exposed 5 by removal of the sheathing and belting are quite short. Also, the paper insulation could be damaged by bending.
Utilities which primarily use PILC cable have been ~..~ where possible, to cross-linked pul~ alyl~n~ (XLPE) cable, espccially in new ' "~ Oll inct~ll and when replacing faulted seetions of " ' PILC cable. As a result, there is 10 sometimes a need to connect XLPE cable to PILC cable.
The invention also addresses problems which arise when crossed linked p~ l.yl~.lc (XLPE) cable is spliced to PILC cable. XLPE cable, along with its splicing and; ~ products, was introduccd some thirty years ago and is becoming more widely acceptcd in the utility industry. XLPE cable has an outer jaeket, made of PVC, 15 a concentric neutral for grounding purposes, a shielding layer of semi-conducting plastics material for relieving electrical stresses, an insulation layer and a conductor. Cable sizes vary, with the most widely used being single conductor 1/0 AWG and 500 mcm in the 5,000 and 15,000 volt ranges. The outer jacket, semi-conducting shielding layer and insulation layers are rubber based and the diameter of a single conductor 500 mcm XLPE
20 is about one and a quarter inches, so the cable is much lighter than PILC cable and easier to handle. Although three conductor XLPE cable is available, it is more common to use three single-conductor XLPE cables.
Splicing of PILC cable to XLPE cable presents problems beeause most PILC
cable is i~ O ' with a low viscosity oil. If this oil is not contained when splicing 25 PILC cable to XLPE cable and the oil migrates into the XLPE cable, ~ of the rubber ~ will take place over time and eventually the joint will fail. The problem of confining the oil occurs because oil pressures of over 100 psi can develop in long downhill lengths of cable, frequently causing outer lead sleeves to swell and split open, creating cable faults irl wet ~ll.;l~ Where there is such an increase of 30 pressure in a sealed run of cable, a vacuum is created in other ar~as where, if the seal is not strong, water may be drawn into the cable. To overcome these problems, ~ .~ have developed special splicing kits for splicing PILC cable to XLPE
cable. These splicing kits include extensive oil sealing devices including mastics, special ~ 2~74478 oil barrier tubings, high pressure tapes, break-out boots and oil block connectors (sleeve and solder types). C~ " the making and breaking down of a transition splice is especially ~ lt ' and costly.
Utilities replace cables as they fail, or for ~c ~ of the system for new 5 customers andlor loading purposes, so breaking down or taking apart of existing splices is quite common. Breaking down of PILC to PILC and XLPE to PILC splices is very labour intensive, messy and time . ~, For example, where a crimped tubular connector is used, it must be cut off and a new tubular connector installed. The oil seal must be broken and remade and cable cutbacks adjusted. Tbis cam result in prolonged 10 power outages, or prolonged reliance upon back-up supplies while cable faults are being repairedl and, for even routine splicing, incrcased iabour costs. There is also an increased risk of oil leakage and ~
There still remains, therefore, a ne~d for an effective alternative to soldered split connectors for joining PILC cables, and unitary, The present invention seeks to eliminate, or at least mitigate, the JiD~Iv of the above-described known connection techniques and has for its object to provide a new method of splicing such cables which does not require the use of molten solder.
Another object is to provide a connector suitable for use in such method.
20 SUMMARY OF THE INVENTION:
According to a first aspcct of the present invention, a comnector ~ for use in connecting end-to-end opposed conductors of power cables comprises a p~ur of connector parts, each connector part comprising at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being steppcd to provide 25 a medial contact surface, and fastcning means for clamping the two connector parts laterally together with their respective said contact surfaces jll-tqroC~l cach contact surface having at least one protrusion and . ' y depression shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are 30 juxtaposed.
Preferably, the connector socket portion is cylindrical and the contact portion serni-cylindrical. The contact surface may then be generally ~" ' Such a connector ~ may be used to join conductors of PILC cable ~ 2t'~478 without using molten solder. Col.v. ~ 'y, each connector part is slid onto the exposed end of the respective conductor and, the connector pa~;ts are juxtaposed and fastened together. The tubular portions are crimped onto the respective conductor ends.
According to a second aspect of the present invention, there is provided a method 5 of splicing together two paper insulated lead-covered cables using two coul ~
connector parts and fastening means, each connector part . , ~ at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being stepped to provide a media'l contact surface, the contact surface having at least one protrusion and .--ll' y depression shaped and positioned so that the protrusion 10 of one connector pa~;t engages the depression of the other connector part to a'lign the connector pa~;ts when the contact surfaces are; , 1, the method including the steps of:
~ " two conductors to be spliced with their respective end portions stripped of insulaaon;
securing the end portions of the conductors in respective socket portions of twoof said connector parts;
aligning the connector pa~;ts with the protrusion and depression of one connector engaging the depression and protrusion, ~ ~iiv~l~, of the otner connector; amd applying fastening means to clamp the connectors laterally together with their 20 respective contact surfaces in contact.
According to a third aspect of the present invention, there is provided a methodof splicing a plurality of cross-linked ~,ol~7 Lllyl~ (XLPE) cables to a paper insulated lead covered (PILC) cable having a c~ ., plurality of condu~orc using a plura'lity of ~urs Of C~ -r '~ C~ connector parts and fastening means, each connector part ~ ~ E. at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being stepped to provide a media'l contact surface, the contact su;face having at least one protrusion and c~r' y depression shaped and positioned so that the protrusiûn of one connector part engages the depression of the other connector part to a'lign the connector parts when the contact surfaces are30 jllY~nrnc.o,i the method comprising the steps of:
removing an outer sheath and belting from the PILC cable and separating its removing insulation from each conductor of the PILC cable to expose an end ~ 4478 portion;
installing an oil barrier tube on each conductor, the tube e~tending between theexposed end portion and the point at which the conductors separate;
installing a first break-out boot at the point of separation of the conductors of the S PILC cable;
installing a second break-out boot upon the three XLPE cables at a prescribed distance from the splice;
preparing the end portion of each of the XLPE cables and pigtailing its concentric neutral wires;
securing bared ends of the PILC conductors and XLPE cables into respective sockets of a plurality of pairs of said connector parts and fastening the parts of each pair together;
creating an oil seal between each oil barrier tube and the associated connector part;
installing insulating and shielding material over each pair of mated connector parts and sealing the material to said oil barrier tubing at one end and, at its other end, to insulation of the Wll~ V XLPE cable;
sealing between the first break-out boot and each oil barrier tube, the sheath of the PILC cable and each oil barrier tube and the sheath of the PILC cable;
connecting the pigtailed neutral wires to the sheath of the PILC cable; and installing an outer sleeve sealing at its one end to the first break-out boot and at its other end to the second break-out boot.
Various other features, objects and advantages of the present invention will become apparent from the following tl~crnrti~n taken in . ;. with the 25 a~ y;..~5 drawings, of u...~"' of the invention, which are described by way of example only.
BRIEF DESCRIPTION OF DRAWINGS:
Figure I illustrates PILC splices in a typical splicing bay of a manhole;
Figure 2 is a view of the manhole from above;
Figures 3a to 3g illustrate steps in the splicing of two paper-insulated covered(PILC) cables;
Figure 4a is a side view of a two-part separable connector showing the two parts ~ ~ 7~47g separated;
Figure 4b shows their contact surfaces;
Figures 5a to 5h illustrate steps in the splicing of a PILC cable to a XLPE cable;
Figures 6a and 6b illustrate a first ,. ~ of the connector contact portions;
5 and Figure 7 illustrates a second - ' ~
DESCRIPTION OF PREFERRED EMBODIMENTS
Figure I shows three PILC cables 10A, l l A and 12A entering a splicing bay 13, 10 typically in a small congested manhole, by way of a duct bank 15. For ~u,.v. ~
only three cables are shown, though there could be more or fewer. Three more PILC
cables 10B, llB and 12B enter by way of a second duct bank 14 at the opposite side of the splicing bay. Cu". r ' g pairs of cable 10A/lOB, llA/llB and 12A/12B are ~ , ' by cable splices 10C, llC and 12C, I~D~ . The splices 10C, llC
15 and 12C are mounted to one wall of the manhole by spaced supports 16A and 16B. As shown in Figure 2, splices 17C are mounted in like manner on the opposite wall and ~ similar p~urs of PILC caoles 17A and 17B.
Each PILC cable comprises three conductors which, in cross-section, each comprise an equal sector of a circle. Each conductor comprises a plurality of copper 20 strands and is wrapped with oil ~ . O ' paper insulation. The three wrapped conductors are surrounded by paper belting and encased in a lead sheath.
Splicing of two of the PILC cables 10A and 10B using the connector;
and procedure according to the present invention will now be described with reference to Figures 3a to 4b, it being d~l~JII ' ' ~ that the other pairs of cables will be spliced in 25 a similar manner and could, in fact, have been spliced previously and be in service. For ~iUll~ e~ CUII~ -- r ' of the cables 10A and 10B have the same reference numbers, but with the suffix A or B as d~JlnUl ' ' The end portions of two PILC cables 10A and 10B protruding into the splicing bay are overlapped as shown in Figure 3a, and lines 20A and 20B marked on cable 10A
30 and 10B, ~ , at the middle of the overlap. At this stage, cable 10B is cut atthe mark 20B. Cable 10A, however, is cut at a position one inch back of the mark 20A.
This dimension of one inch Wll~ r ~ to one half of a distanco Y (Figure 4a) which will separate the ends of the two conductors when spliced and butted up against interior ~ ~17~7~
end faces SlA/51B (Figure 4a) of sockets in their respective illt~
as will be described later. The PVC jacket 22A/22B and the lead sheath 24A/24B are removed from the respective end portions exposing the outer belting 26A and 26B for a specif~ed length as shown in Figure 3b. An outer lead sleeve (not shown) is preparcd 5 and installed over the end of one of the cables and placed down the cable ready for jnc~l1~nn later in the spicing process. The outer belting papers 26A of cable lOA are removed and the insulated conductors 28A, 30A and 32A of cable lOA are separated as shown in Figure 3c. The insulation is stripped to leave bare conductor end portions 34A, 36A and 38A, ~~livt;ly. The outer belting of cable IOB also is removed and 10 its conductors 28B, 30B and 32B separatPd, but the conductor end portions are not stripped of insulation at this time.
The length of each of the barPd end portions 34A, 36A and 38A ~w-~ ,olld, to that of a socket 40A in a socket portion 42A of a two-part separable connector, shown in Figure 4a. The cable splicer then installs a connector part 42A onto each of the barPd 15 ends 34A, 36A and 38A (see Figure 3d).
The connector parts 42A and 42B are identical, so only connector part 42A will be described in detail. As shown in Figure 4a, connector part 42A comprises a cylindrical socket portion 44A having a cylindrical hole 40A extending into it from one end. A solid contact portion 46A protrudes from the other end. The solid contact20 portion 46A is semi-cylindrical in shape and provides a ii~rnPrri~ily extending contact surface 48A extending from the end of the socket portion 44A to a radially extending shoulder 50A. Two holes 52A and 54A extend L~ v~.x;ly through the solid portion 46A and are centered on the cylindrical axis X-X (Figure 4b). When the two connector parts 42A and 42B are matPd with their respective contact surfaces 48A and 48B
25 abutting, fastening screws 56A and 56B extend through the holes and clamp the parts together. Hole 52A has a I ~,u,~; 58A to receive the head of screw 56A and hole 54A is 7.,.~n~ dded to receive the threaded shank of the other screw 56B.
Between the holes 52A and 54A, the contact surface 48A has a pair of ~ fi~rn~ n~, specifically a I , ' ' recess 62A and a ~ , ' y 30 protrusion 64A, disposed on the cylindrical axis X-X. When the two connector parts 42A and 42B are juxtaposed with their respective contact surfaces 48A and 48B incontact and their shoulders 50A and 50B in intimate contact with the ends 106B and 106A, l~i"J~ ,ly, as will be described later, the L~ 64A and 64B engage in the recesses 62B and 62A, ~- ~e ~ivc;ly, to locate the two parts 42A and 42B correctly and align the holes 52A and 54A with holes 54B and 52B, ~ ly, for insertion of the screws 56A and 56B.
Referring to Figure 3d, ensuring that the bared conductor ends 34A, 36A and 5 38A of cable lOA are fully seated in the sockets 40A of tbeir respective connector parts 42A, the splicer crimps the cylindrical socket portions of the connector parts to secure them to the conductor ends. For purposes of illustration only, in Figures 3d to 3g, the comnector part on the middle conductor 30A is shown rotated through 90 degrees relative to the other two connector parts.
As shown in Figure 3e, the splicer positions the conductors 28B, 30B and 32B
of cable lOB alongside the ends of the installed connector parts 42A marks each of the conductors of cable lOB at a position which is back from the end 106A of the ~Ulll r ~- ~ connector part 42A by a distance equal to the spacing between the shoulder SOB and socket interior end face SlB of connector part 42B (Figure 4a), and 15 cuts off the conductors 28B, 30B and 32B at this mark. The splicer removes the paper insulation to leave bare end portions and installs connector parts 42B on them also, as shown in Figure 3f, ensuring, as before, that the conductor ends are fully seated into the respective sockets.
The splicer aligns the mating contact surfaces 48A and 48B of each pair of 20 connector parts 42A/42B and ensures that all three pairs of connector parts line up before crimping the connector parts 42B to the respective conductors of cable lOB. If there is enough room to crimp the connectors in the splicing bay, the splicer can install and tighten the fastening screws 56A/56B before crimping the second set of connector parts.
If the splicing bay is congested, however, and it is difficult to get the crimping tool head 25 onto the connector parts, the splicer may carefully move the cable ends into a clear area, crimp the connector parts, reposition the cable ends in the splicing bay, realign the connector parts and then install and tighten the fastening screws.
Following insertion of the fastening screws (Figures 3g), the spliced conductors are re-insulated by applying insulating tape, squeezed together again and outer belting 30 applied. The outer lead sleeve is slid into place over the splice and its ends beaten down to the diameter of the cable. The outer lead sleeve is solder-wiped, and insulating compound poured into filling holes in the lead sleeve to fill and seal it. The filling holes are then sealed with solder.
~ 2174~8 Application of the invention to the splicing of a three-conductor PILC cable to three, single-conductor XLPE cables will now be described with reference to Figures 5a to 5h.
I~e XLPE cable can be flexed during ~ " l, so it should be notP~d that, as S will become apparent from the following dPc~rir~l~n~ the advantages of using the separable connector for splicing PILC cable to XLPE cable are realised when taking the splice apar~, as opposed to the initial making of the splice.
Referring to Figure Sa and Sb, the PILC end of the cable is prepared as it wouldbe for a PILC to PILC splice. As mentioned earlier, . of the oil to the PILC
10 end is critical. As shown in Figure Sa, oil barrier tubings 62/1, 62/2 and 62/3 are installed over the conductors 28B, 30B and 32B, ~ ly, with an oil seal to be made later at the connector part area. A "break-out" boot 60 (Figure Sb) is installed in the break-out area of the PILC cable, i.e. the point at which the conductors 28B, 30B
and 32B separate. The break-out boot 60 comprises a larger tubular portion at one end 15 fitting closely around the lead sheath 24B and three smaller tubular finger portions 64/1, 64/2 and 64/3 at its other end fitting closely about respective ones of the oil barrier tubes 62/1, 62/2 and 62/3. The breakout boot 60 is filled with either a mastic or resin compound to seal the break out boot 60 to the various parts embraced by it, namely the oil barrier tubes 62/1, 62/2 and 62/3, lead sheath 24B and any exposed belting 26B
20 effectively creating an oil seal in the conductor break-out area of the cable.
Referring to Figures 5c and 5d, the three XLPE cables 66/1, 66/2 and 66/3 are prepared by first removing the PVC outer jacket 68/1, 68/2 and 68/3 to a specified point. Their concentric neutral wires 70/1, 70/2 and 70/3 are pigtailed and drawn back for later bonding to the lead sheath 24B of the PILC cable. The semi-conductive 25 shielding layers 72/1, 72/2 and 72/3 are removed to a specified point and the conductor insulation 74/1, 74/2 and 74/3 removed to leave bare end portions 76/1, 76/2 and 76/3 to accept the connector parts 42A/1, 42A/2 and 42A/3.
A break-out boot 78 is slid onto the three single XLPE cables, each cable in oneof three fingers 80/1, 80/2 and 80/3 of the break-out boot 78. Multilayer 30 insulating/shielding tubes 82/1, 82/2 and 82/3 are then slid onto each of the three XLPE
cables. An outer jacket 84 (see Figure 5h) is slid over the PILC cable end (or over the XLPE cables) and placed down the cable ready for application later in the splicing process. (If a wrap-around jacket is used, it need not be installed at this point). Also, ~- 2~7k~78 a set of separate insulating and shielding tubes could be used instead of each of the mulalayer tubes.
Referring to Figure Sd, three p~urs of ~parable connector parts 42A/l and 42B/lB, 42A/2 and 42B/B, and 42A/3 and 42B/3 are fastened together and crimped onto 5 the respective PILC conductor ends, ensuring that the conductors are fully seated into the bore of the connector. Because the XLPE cables are more flexible than PILC cables, and separate, each of the single conductor XLPE cables can be flexed to insert its end into the open end of the ~O~ connector part, which is then crimped. After the connectors are installed, the oil-stop process is completed on the PILC end of the 10 connector. As shown in Figures Se and Sf, this involves applying either mastic tape or high pressure tape to form a seal 86 between the crimped portions of connector part 42B
and the oil barrier tube 62. The splice is then ready for rc ~ ' ~
The insulating/shielding tubes 82/1, 82/2 and 82/3 are slid into place over the connectors and shrunk down over the oil barrier tubes 62/1, 62/2 and 62/3 at one end 15 and the insulation 74/1, 74/2 and 74/3 at the other end. The pigtailed neutral wires 70/1, 70/2 and 70/3 are brought across the splice from the XLPE end cable and bonded to the lead sheath 24B. The break-out boot 78 is shrunk into place to bond to the three XLPE cables, as shown in Figure Sg. As shown in Figure 5h, the outer jacket 84 is installed to completely cover the splice and bonded at one end to the boot 78 and at the 20 other end to the PVC jacket of the PILC cable, to seal against moisture ingress.
An advantage of the present invention is that, when cable ., ~ is necessar~v and involves splicing into such an existing PILC to XLPE cable splice, it is possible to take apart the outer jacket 84 and shielding and insulating . , 82/1, 82/2 and 82/3, and unfasten the connectors 42A/42B without disturbing the cable 25 cutbacks and oil stop devices. New connector parts 42A crimped onto the ends of the conductors of the new cable are fastened to the mating connector parts 42B of the existing cable and the insulation, shielding and outer jacket restored. This is especially a~ ~ when the PILC cable is to be put back into service. By contrast, previously known PILC to XLPE splices using crimped one-piece connecting sleeves30 must be completely broken down, the crimped connecting sleeve cut out, the cable cutbacks must be adjusted and the oil . ,~ Not having to break down the oil ~ r- - and/or adjust cable cutbacks saves a lot of work and decreases recover,v time and costs.
74~78 The connector according to the present invention could also be used for single conductor in-line XLPE and PILC splices. If a section of cable had to be replaced between cable splices, use of the separable connector in the original splice would a.l.. ~ 'y avoid re-adjustment of the cable cutbacks, thereby reducing down-time5 and expenses, and would maintain the splice in its original position in the splicing bay.
The design of the mating contact surfaces 48A/48B of the separable connector parts 42Al42B is such that intimate contact after the fastener is tightened is ''~1 assured. The distance d (Figure 4b) between the centre of protrusion 64A and surface 50A is the same as the distance between the centre of depression 62B and the end 106B
10 of the coMector part. Hence, the contact portions are h~.1.~1.1, " so the connector parts may be identical. The curvature and positioning of the depression/protrusion aids in the alignment of the parts in all directions when mated, which allows for easy insertion of the fastening screws 56Al56B into their holes, and the intimate contact between the end faces 106AIB and shoulders SOBIA. When assembled, the separable 15 connector parts form a low profile, cylindrical connector which provides a smooth contour for the applying of insulating materials.
Various rn~Ylifi~hnne to the above-described ' ' are possible without departing from the scope of the present invention.
A ~Irst ,~ is illustrated in Figures 6a and 6b. The connector parts 20 comprise cylindrical socket portions 44A and 44B as before, but their solid, mating contact portions 46A' and 46B' differ from those of the connector parts of the first In particular, the holes 52A and 52B are concentric with the l , ~ 1 ~lVLI~ ' 64A and 64B and the holes 54A and 54B are concentric with tbe y ~ - 62A and 62B, l~Liv~ly. C~ the length of the 25 mating contact surfaces 48A and 48B is shorter, which further facilitates "
especially in confined spaces.
Figure 7 shows another m~lif ~h'on which results in a shorter overall connector length. In this case, a single fastening bolt 56 extends through a hole 54 between the protrusion and depression and receives a hexagonal nut 88. In this case, instead of a 30 . ' Ci, the moutb 86 of hole 54 is hexagonal to conform to the hexagonal nut 88 and hold it as the bolt 56 is tightened. It should be noted that the two connector parts are still identical.
The separable connector parts may be provided in various diarneters to fit various ~ ~174~78 sizes of c~ rf<-r.e Instead of crimping, the connector parts may be attached to the conductors by other means, such as clamping screws. Although the above-described~ ho.~ - have only one protrusion and one . ,' y depression on each contact portion, it would be possible to have more. For example, a duplicate set of holes 5 52A and 54A, protrusion 64A and depression 62A could be provided alongside the first set. It is also envisaged that, whereas the described i ' ' has the protrusion and depression between the screw holes, the holes could be between the protrusion and depreesion instead. ~ ,' ' protrusions and .L,~ are preferred because they result in more uniform electrical stress and fewer "hot spots" as compared with 10 contours having points or edges.
The connector patts and fastening screws may be made of any material which conforms to the standards and regulations of the industry.
An advamtage of the connectors of the present invention is that, since the two connector parts may be identical, ~ -~nnne and stocking costs may be reduced.
Although only the splicing of PILC and XLPE cables has been described herein, it should be a~ ' that the invention is also applicable to other kinds of power cables. Likewise, the invention applies to cables having voltage and current ratings other than those specified herein and which use different materials.
Although ~mho~ ntc of the invention have been described and illustrated in 20 detail, it is to be clearly understood that the same are by way of illustration and example only and not to be taken by way of the limitation, the spirit and scope of the present invention being limited only by the appended claims.
Claims (13)
1. A connector arrangement for use in connecting end-to-end opposed conductors of power cables and comprising a pair of connector parts, each connector part comprising at its one end a tubular socket portion and at its other end a solid contact portion, the contact portion being stepped to provide a medial contact surface, and fastening means for clamping the two connector parts laterally together with their respective said contact surfaces juxtaposed, each contact surface having at least one protrusion and a complementary depression, the protrusion and depression being shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are juxtaposed.
2. A connector as claimed in claim 1, wherein the connector parts are identical, a spacing between the protrusion and one end of the contact surface being substantially equal to a spacing between the depression and an opposite end of the surface.
3. A connector arrangement as claimed in claim 1, wherein the protrusion and depression are hemispherical.
4. A connector arrangement as claimed in claim 1, wherein each connector part has a clearance hole and a screwthreaded hole spaced apart so that, when the contact surfaces are juxtaposed with the complementary protrusions and depressions engaged, each clearance hole is coaxial with the screwthreaded hole of the opposed connector part, the fastening means comprising a pair of screws each to extend through a respective clearance hole and engage in the corresponding screwthreaded hole.
5. A connector arrangement as claimed in claim 1, wherein the contact surface has a protrusion and a depression spaced apart longitudinally and each connector part has a clearance hole and a screwthreaded hole, each extending through a respective one of the protrusion and depression, and the fastening means comprises a pair of screws each to extend through a respective clearance hole and engage in the corresponding screwthreaded hole.
6. A connector arrangement as claimed in claim 1, wherein the contact surface has a protrusion and a depression spaced apart longitudinally of the connector and each part has a clearance hole extending therethrough between the protrusion and the depression, the fastening means comprising a screw extending through the aligned holes and secured by a nut, the nut being accommodated in a recess in one of the parts and a head of the screw being accommodated in an identical recess in the other of the parts.
7. A connector arrangement as claimed in claim 1, wherein the connector parts, when fastened together with their respective contact surfaces juxtaposed, form aconnector with a substantially contiguous outer surface.
8. A connector as claimed in claim 7, wherein each tubular socket portion is substantially cylindrical and each solid contact portion is substantially semi-cylindrical, said contact surface extending substantially diametrically.
9. A connector arrangement as claimed in claim 1, wherein the protrusion is spaced from one end of the contact surface by a distance substantially equal to a spacing between the depression and an opposite end of the contact surface.
10. A method of splicing together two paper insulated lead-covered cables using pairs of cooperating connector parts and fastening means, each connector part comprising a tubular socket portion at one end and, at its other end, a solid contact portion, the contact portion being stepped to provide a medial contact surface, the contact surface having at least one protrusion and a complementary depression shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are juxtaposed, the method including the steps of:
positioning two conductors to be spliced with their respective end portions stripped of insulation;
securing the end portions of the conductors in respective socket portions of two of said connector parts;
aligning the connector parts with the protrusion and depression of one connectorpart engaging the depression and protrusion, respectively, of the other connector part;
and applying the fastening means to clamp the connector parts laterally together with their respective contact surfaces in contact.
positioning two conductors to be spliced with their respective end portions stripped of insulation;
securing the end portions of the conductors in respective socket portions of two of said connector parts;
aligning the connector parts with the protrusion and depression of one connectorpart engaging the depression and protrusion, respectively, of the other connector part;
and applying the fastening means to clamp the connector parts laterally together with their respective contact surfaces in contact.
11. A method as claimed in claim 10, wherein a first of the connector parts is attached to the conductor of one cable, and the end portion of the conductor of the other cable is overlapped with the first connector part and cut to length using the first connector part as a guide.
12. A method of splicing a plurality of cross-linked polyethylene (XLPE) cables to a paper insulated lead sheathed (PILC) cable having a corresponding plurality ofconductors, using two cooperating connector parts and fastening means, each connector part comprising at its one end a tubular socket portion and a solid contact portion at its other end, the contact portion being stepped to provide a medial contact surface, the contact surface having at least one protrusion and complementary depression shaped and positioned so that the protrusion of one connector part engages the depression of the other connector part to align the connector parts when the contact surfaces are juxtaposed, the method comprising the steps of:
removing an outer sheath and belting from the PILC cable and separating its conductors;
removing insulation from each conductor of the PILC cable to expose an end portion;
installing an oil barrier tube on each conductor, the tube extending between theexposed end portion and the point at which the conductors separate;
installing a first break-out boot at the point of separation of the conductors of the PILC cable;
installing a second break-out boot upon the three XLPE cables at a prescribed distance from the splice;
preparing the end portion of each of the XLPE cables and pigtailing its concentric neutral wires;
securing bared ends of the PILC cable conductors and XLPE cable conductors into respective socket portions of a plurality of said connector parts and fastening each connector part secured to a PILC cable conductor to a connector part secured to an XLPE cable conductor;
creating an oil seal between each oil barrier tube and the associated connector part;
installing insulating and shielding material over each pair of mated connector parts;
sealing between the first break out boot, each oil barrier tube and sheath of the PILC cable;
connecting the pigtailed neutral wires to the sheath of the PILC cable; and installing an outer sleeve sealing at its one end to the first break-out boot and at its other end to the second break-out boot.
removing an outer sheath and belting from the PILC cable and separating its conductors;
removing insulation from each conductor of the PILC cable to expose an end portion;
installing an oil barrier tube on each conductor, the tube extending between theexposed end portion and the point at which the conductors separate;
installing a first break-out boot at the point of separation of the conductors of the PILC cable;
installing a second break-out boot upon the three XLPE cables at a prescribed distance from the splice;
preparing the end portion of each of the XLPE cables and pigtailing its concentric neutral wires;
securing bared ends of the PILC cable conductors and XLPE cable conductors into respective socket portions of a plurality of said connector parts and fastening each connector part secured to a PILC cable conductor to a connector part secured to an XLPE cable conductor;
creating an oil seal between each oil barrier tube and the associated connector part;
installing insulating and shielding material over each pair of mated connector parts;
sealing between the first break out boot, each oil barrier tube and sheath of the PILC cable;
connecting the pigtailed neutral wires to the sheath of the PILC cable; and installing an outer sleeve sealing at its one end to the first break-out boot and at its other end to the second break-out boot.
13. A connector part for use in combination with a similar connector part to connect end-to-end opposed conductors of power cables and comprising an elongate body having a socket extending into one end of the body to form a tubular socket portion and having at its other end a solid contact portion, the contact portion being stepped to provide a medial contact surface, each contact surface having complementary protrusions and depressions shaped and positioned so that, when the connector part is clamped to the similar connector part with its said contact surface juxtaposed to that of the similar connector part, the protrusion of one connector part will engage the depression of the other connector part to align the connector parts.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2174478 CA2174478A1 (en) | 1996-04-18 | 1996-04-18 | Method of splicing cables and connectors for use therein |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2174478 CA2174478A1 (en) | 1996-04-18 | 1996-04-18 | Method of splicing cables and connectors for use therein |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2174478A1 true CA2174478A1 (en) | 1997-10-19 |
Family
ID=4158018
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2174478 Abandoned CA2174478A1 (en) | 1996-04-18 | 1996-04-18 | Method of splicing cables and connectors for use therein |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2174478A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1997861A3 (en) * | 2007-05-11 | 2009-10-07 | Tyco Electronics UK Limited | Sealing tape |
| CN113451822A (en) * | 2021-07-13 | 2021-09-28 | 四川华丰科技股份有限公司 | Integral high-current connector |
-
1996
- 1996-04-18 CA CA 2174478 patent/CA2174478A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1997861A3 (en) * | 2007-05-11 | 2009-10-07 | Tyco Electronics UK Limited | Sealing tape |
| CN113451822A (en) * | 2021-07-13 | 2021-09-28 | 四川华丰科技股份有限公司 | Integral high-current connector |
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| Date | Code | Title | Description |
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