Disconnection of the cable TPP 10x2 the same color of the cores. Cutting and preparing cables for installation. List of laboratory and practical works
COLLECTION
LABORATORY AND PRACTICAL WORKS
according to MDK.05.01 Technology of installation and operation of fiber-optic, copper-core cable and overhead lines
name of the academic discipline (PM, MDK)
class numbers from 1 on 19 .
according to the program approved by the deputy. director for water resources management A.V. Logvinov
« 3 » October 2013 Full name
for the specialty 210709 Multichannel telecommunication systems
code and name of the specialty
designed for 38 hours (hours).
Compiled by the teacher I.N. Alekhine
CONSIDERED
at a meeting of the cyclic commission " Telecommunication systems and communication networks»
name P(C)K
Chairman _____________/ O.V. Sirotkina/
signature full name
Protocol __ 2 __ from "_ 14 _»_____ 10 _____ 2013 G.
number date
Samara, 2013
List of laboratory and practical works
according to MDK.05.01 Technology of installation and operation of fiber-optic, copper-core cable and overhead lines
Laboratory work No. 1. Installation of CCI cable using 3M technology………….3
Laboratory work No. 2. Installation of the ISS cable using 3M technology ………....9
Laboratory work No. 3. Preparing OK for installation, installation
optical couplers…………................................................................ ........................................14
Laboratory work No. 4. Preparing an optical fiber for
Splicing……………………………………………………………………...21
Practical work No. 1. Calculation of RH parameters…………………………….26
Laboratory work No. 5. Installation of optical crosses……………………..33
Practical work No. 2. Measurements during technical operation
LKS FOLP………………………………………………………………………….38
Practical work No. 3. Measurements of hose covers OK…………….43
Laboratory work No. 6. Emergency recovery work on
LKS FOLP………………………………………………………………………….48
Practical work No. 4. Measurements during ATS on
LKS FOLP………………………………………………………………………….54
Practical work No. 5. Layout of construction lengths
and mounted couplings in the regeneration areas between the terminal
paragraphs…………………………………………………………………………….59
Practical work No. 6. Drawing up a distribution scheme
optical fibers in the regeneration area…………………………….65
Practical work No. 7. Drawing up a diagram of the organization of communication on
ECU………………………………………………………………………………….71
Lab #1
Job Title:Installation of CCI cable using 3M technology
1. The purpose of the work:
1.1 Familiarize yourself with the installation of the CCI cable using 3M technology.
2. Preparation for work:
2.1 Study the sequence of operations for installing the CCI cable.
3. Literature:
3.1 Alekhin I.N. "Technology of installation and operation of fiber-optic, copper-core cable lines." Textbook for open source software. – Samara, 2013.
3.2 Alekhin I.N. "Technology of installation and maintenance of guide systems". Textbook for open source software. – Samara, 2013.
3.3 Andreev V.A., Burdin A.V., Kochanovsky L.N., Portnov E.L., Popov V.B. "Guiding telecommunication systems": A textbook for universities. In 2 volumes. Volume 2 - Design, construction and technical operation / - 7th ed., Revised. and additional - M.: Hotline-Telecom, 2010. - 424 p.
4. Main equipment:
4.1 CCI cable, sleeve of appropriate material and size.
4.2 Connector UY-2, pliers E-9Y.
4.3 MS modules 2 .
4.4 Stands of the NSE laboratory.
5. Task:
5.1 Preparation of the workplace.
5.2 Preparing the CCI cable for installation.
5.3 Installation of CCI cable.
6. Order of performance of work:
6.1 Cutting the cable (preparation for installation).
6.2 Splicing
6.3 Restoration of protective coatings.
7.1 Job title.
7.2 The purpose of the work.
7.3 Installation of CCI cable using 3M technology.
7.4 Sketch drawing 1.
7.5 Answer security questions.
8. Security questions:
8.1 Stages of installation of the CCI cable.
8.2 Methods for splicing the cores of the CCI cable.
8.3 What is included in the MVSSK kit.
8.4 Purpose of UY-2 and MS 2 .
8.5 For what cable capacity are UY-2 connectors and MS 2 modules used.
8.6 What is included in the RB-4036 tool kit.
8.7 Composition and purpose of modules 4000D, 4000С, 4008D, 4005DPM.
8.8 What is the splicing head used for?
8.9 What the adapter is used for.
8.10 What is the pressing device used for?
The work was compiled by the teacher: /Alekhin I.N./
APPENDIX
Installation of CCI cable
Installation of GTS cables consists of 3 stages:
1. Cutting the cable (preparing the cable for installation):
Selection of the coupling taking into account the capacity of the cable (according to the diameter of the cores, according to the type of cable);
The place of the cut of the shell is determined;
The sheath is removed, the cable core is disassembled into bundles.
2. Splicing cores:
Primary colors (white, red) are combined with secondary colors (green, blue, orange, brown, gray).
3. Restoration of protective coatings:
Belt insulation is repaired using 3M tapes, wraps around the cable core and protects the conductor insulation from accidental damage.
The shield is restored with shield wire, which is used to reduce interference.
The shell is restored by a sleeve, which is pushed onto the splice.
Splicing cable cores with UY-2 single-core connectors
More than 40 years ago, 3M introduced the world's first U-shaped connector, the ScotchlokTM connector, which offers many benefits:
Possibility of connecting conductors of different diameters;
Does not require stripping, thus the splicing process
significantly accelerated and simplified;
Provides high quality contact for the lifetime of the cable (45 years).
UY-2 single core connectors are used for splicing cores of low capacity cables (from 10 to 100 pairs) with and without hydrophobic filler, as well as for splicing spare cores in high capacity cables. The connector is designed to connect copper conductors with a core diameter of 0.4-0.7 mm with paper, polyethylene or polyvinyl chloride.
solid insulation without their preliminary stripping. It consists of the following parts: housing, cover and contact element (Figure 1). The body of the connector is made of transparent polypropylene and filled with a hydrophobic mass that prevents moisture from affecting the junction of the conductors. The cover is also made of polypropylene, it has a built-in contact element made of phosphor bronze, which provides high-quality and reliable connection (5th category of contact). Service life UY-2-45 years.
Installation of cables using a single-core connector is carried out using E-9Y press tongs, which provide biting and pressing of conductors (Figure 2).
During installation, VSSK and MVSSK kits are used, which allow mounting both straight and split couplings.
Splicing cable cores with MS 2 series modular connectors
The installation of the core of multi-pair cables is carried out in the same sequence, in which the bundles most distant from the cableman are first spliced.
The MS 2 series 25-pair modules are recommended for splicing 100 or more pairs of pressurized cables. Modules of the MS 2 series are designed for simultaneous splicing of 25 pairs of copper or aluminum conductors of a telephone cable without preliminary stripping, they allow connecting conductors with a diameter of 0.32 to 0.7 mm with polyethylene or paper insulation.
The RB-4036 tool kit is shown in Figure 3.
The MS 2 4000D module is designed for simultaneous direct connection of 25 wire pairs. The module consists of three parts: base, body and cover (Figure 4).
The cores coming from the telephone exchange are attached to the base of the module, the conductors of the subscriber line from the side of the cover. Modules of the MS 2 series for indoors are supplied dry (4000D), outdoors with hydrophobic filling (4000C). The hydrophobic filled capsule type MS 2 4075S is used to protect the cable from moisture ingress, recommended for use on high capacity, non-pressurized cables.
The MS 2 4008D module is designed for paralleling pairs when switching and repairing cables without interrupting communication and allows you to connect directly to the cable cores anywhere except for the splice. The difference lies in the fact that there are no knives in the lower part of the module body, so the cores inserted into the module base are not cut off during crimping.
The MS 2 4005DPM module is designed to switch cables and allows you to connect to the coupling anywhere except for the splice , to mounted modules of the MS 2 series. The module consists of three parts: an insulator, a body and a cover. The base of the module is painted blue, the contacts are rotated by 90 0 and offset from the center.
The packaging of the MS 2 4000D and MS 2 4008D modules includes an adapter that is designed to properly fix the parts of the module in the splicing head.
The assembled splice using MS 2 modular connectors is shown in Figure 5.
Figure 5. Assembled Splice Using MS 2 Modular Connectors
A few decades ago, they were used for conventional telephony. The design of these cables has not changed much, but the equipment that is “hung” on these cables has noticeably improved. Today, the speed of information transfer through xDSL-technologies reaches hundreds of Mbps. Due to the presence of a huge number of different cables, it is impossible to do without marking in the name of the cables indicating the main parameters.
Consider, for example, 20x2x0.4 for the purpose of decryption example:
telephone (T) cable with polyethylene core insulation (P), with polyethylene insulation of the sheath (P), with a film screen (ep), with hydrophobic filler (Z) and armored cover (B).
Numerical designations are deciphered as follows:
20x2 - the cable has 20 pairs in its core;
0.4 - core diameter in mm.
In TSV cables, the second and third letters are deciphered as follows:
The letter C - station, B - vinyl shell.
For low-pair cables, the letter M is added in the marking - MTPPZ, MTPPepZ.
Cables KAPZ, KAPZop practically do not differ from MTPPZ and their decoding is as follows: cable (K) subscriber (A) with polyethylene insulation (P) and hydrophobic filler (Z).
About systems of stranding of cores in a cable of the TPP type
Today, stranded cables are no longer produced, but still used.
Rice. 1 - arrangement of pairs in a twisted cable.
Rice. 2 - Construction of the loop cable
Such a cable has a poor color of cores - 1 pair is red, 2 pairs are blue, the remaining pairs are of the same color. Counting pairs in such a cable is difficult, which contributed to poor quality work and frequent soldering errors. The positive side of this cable is, perhaps, the smaller thickness of the cable, when compared with bundled twist.
Beam twist
Rice. 3 - beam twist
The figure shows: under the number 1 - a pair of wires; 2 - four lived; 3 - elementary beam; insulation; 5 - screen; 6 - p / fl shell; 7 - screen wire.
A cable with a similar twist is a product in which pairs are twisted in bundles of 5 or 10 pieces. The bundles are formed by two threads that wrap around the bundle, and also contain a special colored thread to distinguish the bundles from each other.
Rice. 4 - Color table for pairs in the top ten of the cable TPV, CCI, TSV, TPPep, TPPepZ
Rice. 5 - Coloring of CCI cable pairs
Charging BKT box plinths with TPPepZ cable
The procedure for counting pairs and fours by color is prescribed in the relevant standards.
The cores of the cables assembled in bundles are wrapped with PVC tape in order to protect the insulation from the negative effects of temperatures. The next layer is a screen and a tinned core. And then the shell. Initially, the TPV cable was made with a vinyl sheath. In the process of using the cable in the ground, it was noticed that it loses its properties due to the action of moisture. Later, the CCI cable with a polyethylene sheath was developed, which turned out to be less susceptible to moisture, but more fire hazardous. Therefore, depending on the conditions in which the cable is used, a modification with an appropriate sheath is selected.
You can receive the ordered goods from the company "Vionet" in the following cities:
In Anapa, Arkhangelsk, Abakan, Adler, Aktau, Almetyevsk, Aktyubinsk, Almaty, Asnan, Anadyr, Angarsk, Astrakhan, Apatity, Atyrau, Arzamas;
In Blagoveshchensk, in Balakovo, in Biysk, in Belgorod, in Balkhash, in Borovichi, in Bryansk, in Bratsk, in Belogorsk, in Borisoglebsk, in Berezniki, in Barnaul, in Bugulma, in Budennovsk;
In Vologda, in Volgograd, in Vladimir, in Veliky Novgorod, in Volgodonsk, in Velikiye Luki, in Voronezh, in Vladivostok, in Volzhsk, in Volzhsky;
In Zheleznodorozhny; in Yekaterinburg, in Dzerzhinsk, in Dimitrovgrad, in Zabaikalsk, in Zelenodolsk, in Izhevsk, in Ivanovo, in Yoshkar-Ola, in Irkutsk;
In Kurgan, Kazan, Kaluga, Krasnodar, Kostroma, Kemerovo, Kamensk-Uralsky, Karaganda, Kirov, Kokchetav, Kolomna, Kotlas, Krasnoyarsk, Kuznetsk, Kursk, Kustanai, in Kyzyl-Orda, in Kaliningrad, in Kamyshin, in Komsomolsk-on-Amur;
In Moscow, in Magadan, in Murmansk, in Miass, in Magnitogorsk, in Lipetsk;
In Nizhny Tagil; in Nizhny Novgorod, in Nizhnekamsk, in Novy Urengoy, in Naberezhnye Chelny, in Noginsk, in Nalchik, in Neftekamsk, in Nevinnomyssk, in Novorossiysk, in Novocheboksarsk, in Novomoskovsk, in Novokuznetsk, in Noyabrsk, in Novosibirsk, in Nizhnevartovsk;
In Orsk, in Orel, in Obninsk, in Orenburg, in Omsk, in Oktyabrsky;
In Perm, in Podolsk, in Petrozavodsk, in Pskov, in Penza, in Petropavlovsk-Kamchatsky, in Petropavlovsk, in Pushkino, in Pavlodar, in Pyatigorsk;
In Ryazan, in Rybinsk, in Rostov-on-Don, in Rossosh;
Petersburg, Syktyvkar, Sevastopol, Severodvinsk, Salavat, Stary Oskol, Saransk, Saratov, Samara, Serpukhov, Smolensk, Semipalatinsk, Sochi, Solnechnogorsk, Stavropol, Sterlitamak , in Syzran, in Surgut;
In Tver, in Tula, in Tuapse, in Tyumen, in Tambov, in Taganrog, in Tolyatti, in Taraz, in Taldy-Kurgan, in Tomsk;
Ulyanovsk, Ufa, Ussuriysk, Ulan-Ude, Ukhta, Uralsk, Ust-Kamenogorsk, Khabarovsk, Khanty-Mansiysk, Chita, Cherepovets, Chelyabinsk, Cheboksary, Chimkent, Engels , in Ekibastuz, in Yaroslavl, in Yakutsk, in Mines, in Yuzhno-Sakhalinsk.
1- outer protective cover, 2-armor,.3-metal sheath, 4-belt insulation,
5-core insulation A, B, D, O, P, G and D-length designation
Figure 52 - Armored cable cutting and heat shrinkable glove
Table 2 - Dimensions of cable cutting for mounting couplings SE (Fig. 52)
| Couplings | Cross-section of cable conductors, mm 2 at voltage, kV | Dimensions, mm | |||||
| A | B | O | P | F | |||
| SE-1 | 10-70 | 16-50 | |||||
| SE-2 | 95-120 | 70-95 | |||||
| SE-3 | 150-185 | 120-150 | |||||
| SE-4 | 185-240 |
Cutting technology is as follows. At a distance A from the end of the cable, a bandage of two or three turns of galvanized steel wire is applied. The cable yarn is unwound up to the bandage and left for later use when mounting the coupling. The second bandage is applied at a distance B from the first. A hacksaw with a cutting depth limiter cuts the armor here and removes it and the pillow under it. To remove the lead or aluminum sheath, two annular cuts are made on it at half the thickness of the sheath with a knife with a cutting depth limiter at a distance of O and L. In the area between the cuts, the sheath is temporarily left, removing it behind the second cut. The lead sheath is removed in two steps: from the second incision, two longitudinal cuts are made to the end of the cable at a distance of 10 mm and this strip is removed, then the rest of the sheath is removed; the aluminum sheath is removed using a spiral cut to the end of the cable. Unwinding semi-conductive paper and belt insulation, cut them off at the edge of the shell. The wiring of cable cores is in most cases done manually (possibly using special templates), avoiding sharp bends. At the end of the wiring, the temporarily left part of the shell is removed. To remove the core insulation, the cable is first tied up at the cut point with several turns of cotton threads, the length of the exposed section depends on the method of termination or connection of the cores.
SEQUENCE OF OPERATIONS FOR CUTTING ARMORED CABLE. Armored before cutting is cleaned of dirt, then it is marked and cut. To cut the cable, it is necessary to use special tools that allow you to perform work quickly, with good quality and safely.
The sequence of operations for cutting the armored cable is shown in Figure 73.
1- determine the dimensions of the cut according to the tables and mark the end of the cable
2- install a thread bandage (from threads) No. 1 on the outer protective cover
3- carefully cut and remove the outer protective cover
4- strip the cable armor for the length of the segment Br
5- install wire bandage No. 2
6- cut off the armor neatly and remove
7- install a thread bandage No. 3 on the belt insulation for the length of the segment By
8- carefully cut off the belt insulation and remove
9- strip the wires from the insulation on the segment Zhi and delete
10- clean and degrease the armor and metal sheath of the cable for soldering
11- put the tinned end of the copper jumper on the armor and sheath of the cable and install wire bandages No. 4 and 5 on the armor and on the sheath
12- dilute and warm up the blowtorch
13- carefully solder the copper jumper to the armor and sheath (without melting the metal sheath) and secure the solder with wire bandages
Termination of cables. The termination of cables is carried out depending on the magnitude of the voltage and the place of connection of the cable in the following ways: end sleeves, end seals and gloves. Terminations and terminations are used to terminate cables in switchgears. Terminations are used indoors, end sleeves are used outdoors. The main types of couplings: KNE, ELF, KNP; terminations: KV, KVEtp, etc. Terminations are often used to transition a cable line into an overhead line. End terminations - for connecting the cable to the receiver or switching device or switchgear. After installation, the terminations and terminations are filled with cable mastics and compounds, epoxy or bituminous, and modern thermal or cold shrinking technologies are also used (see page 70).
Dry cutting methods at voltages up to 1000 V can be carried out in the form of an end seal in rubber gloves, heat-shrinkable tubes, an end seal with PVC tape and varnishes, etc. for connection to electric motors in terminal boxes. End terminations flexible cables are made using insulating rubber, heat-shrinkable tubes or gloves made of silicone rubber (TCR) or electrical insulating sleeves. The conclusion of the cable cores into the TKR tube has become widespread, the sequence of such termination is as follows. An external rubber hose is given in a section of 350 mm from the end of the cable. If there is a metal screen, it is removed from each core, leaving 8-10 wires each, which are twisted into a bundle from three phases and, together with the grounding core, are connected to the grounding clamp. The insulating rubber of the cable core is released from the semi-conductive layer in a section 200 mm long and TKR tubes of the corresponding inner diameter are put on top of the insulating rubber. The tube is put on with the capture of the unremoved layer of semi-conductive rubber. Compressed air can be used to press the tube, when pressing without compressed air, the tube is preliminarily kept for 15–20 minutes in B-70 or Kalosha gasoline, after the gasoline evaporates, the tube restores its properties. Along the entire length of the cut part, including the tube, a bandage is applied in increments of 20-30 mm with an end 100 mm before the cable lug. The cut of the hose sheath is protected with a special tape.
Core termination cable in most cases is carried out by crimping with the help of
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Figure 54 - Termination of PVC for a single-core cable. Heat-shrinkable glove KW for three-core cable.
Connecting cables. Non-separable connection of individual cable sections is carried out using connecting, branching and locking couplings filled with epoxy or bituminous compounds (compounds). Collapsible connections are made in special metal boxes. Compound lived cables are produced using connecting sleeves, lugs or flasks. The cores prepared for connection are inserted into the sleeve (flask) until it stops with the ends in the middle of the sleeve and are pressed or soldered, the sharp edges of the sleeve are twisted.
Connecting flexible cables is carried out using connecting collapsible and detachable boxes, couplings, plug-in couplings or vulcanization. During vulcanization after cutting, all veins are shifted from one of its ends along the length of the veins by 50 mm clockwise. The connected and crimped cores are wrapped individually with two layers of unvulcanized rubber tape, on top of which one layer is overlapped
Figure 55 - Cutting a four-core cable for connection or for connection to a mine starter or machine.
calico ribbon. The space between the cores is laid out with strips of non-vulcanizable rubber. The connected cores are wrapped with several layers of "raw" rubber tape, each outer layer is wiped with gasoline. The upper outer layer is rubbed with talc and wrapped with two layers of calico tape, after which the connected part of the cable is vulcanized in a special apparatus for 40-50 minutes. After the cable has cooled, the calico tape is removed, and the junction is cleaned with sandpaper. In quarries, to connect high-voltage cables with rubber insulation of the formula 3 + 1 + 1, high-voltage plug-in connectors RVSh-6 (10) / 400 are used in the design of UHL-1, IP - 67. Special elastic couplings and crimping gloves are also used.
Connection of armored cables. Armored cables are connected using couplings: at voltages up to 1000 V - cast iron or other, and at voltages above 1000 V - SE epoxy couplings, lead SS, polyurethane joint ventures, heat-shrinkable ST and cold shrink couplings. By appointment, the couplings are connecting, branching and locking. Connecting cables are designed to connect cables, branch cables - to branch the third cable at an angle (U-shaped and T-shaped), stoppers are designed to prevent cable mass from running off during vertical laying. Couplings are generally non-separable and are used for permanent connection of cable segments.
After installation, the couplings are filled with special mastics and compounds based on oil-bitumen, epoxy or polyurethane mixtures. Epoxy couplings SE are filled at the installation site with an epoxy compound, cast-iron couplings SC are filled with bitumen or epoxy composition. CC brand lead couplings are used with a protective hermetic or non-hermetic casing. Temporary collapsible connection of cables in underground workings is carried out using busbar boxes KR, KShV or VSHK. Epoxy couplings are intended for connection of power cables for voltage 1, 6 and 10 kV with paper and plastic insulation with copper and aluminum conductors. Cast iron couplings are used for cables with paper insulation in an aluminum or lead sheath for voltages up to 1 kV. Lead and epoxy sleeves are designed to connect cables for voltages of 6 and 10 kV.
When using bituminous compounds, they are preheated to a temperature of 140-180 degrees, which is dangerous for personnel, therefore, a heated container with a mass (for example, a bucket) cannot be transferred from hand to hand of another person, but must be transferred only to the one who removed this container fire or other heating device. Epoxy compounds cannot be heated using heating devices and fire - their operating temperature is plus 15-20 degrees, therefore, in cold weather, before use
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SE: 1-wire bandage, 2-grounding conductor soldered to the armor and metal sheath of the cable, 3-seal, 9-core cable, 10-sleeve or flask. KNE: 1-tip for connecting the terminals of the coupling with wires of the overhead line, 2-insulator and cable core, 4-grounding conductor, 6-clamp connecting the sheath and armor of the cable with the grounding conductor.
Figure 56 - Couplings SS, SE and end couplings KMCH and KNE-10.
When working in cold weather, a temporary tent with a device for air heating and ventilation is set up at the coupling installation site. When working with epoxy mixtures, people should use protective gloves, for example, medical ones. To connect armored cables with plastic insulation and sheath for voltages up to 6 kV, steel couplings are used, filled with an epoxy or polyurethane compound and sealed with rubber sealing rings. To connect low-voltage armored cables to control devices, dry methods of cutting cables are used, which do not require casting with cable mass. To connect the power cable to high-voltage devices, special cable fittings are used, while both dry cutting methods and casting with insulating cable mass are used.
Figure 57 - SE-50 coupling kit
Heat shrink and cold shrink technology. Currently, heat-shrinkable sleeves and terminations, as well as cold shrink kits (which do not require heating), are increasingly used. These methods of connecting cables allow you to increase labor productivity (installation time is reduced by about half), reduce the use of harmful epoxy compounds and hazardous bituminous compounds. The set of couplings includes connecting sleeves made of copper, aluminum or bimetallic (copper-aluminum), and insulating materials. The heat-shrinkable sleeve has polymer heat-shrinkable tubes, cuffs, several layers of insulation and screens made of conductive and semi-conductive materials. In the process of heating with a gas burner flame, the coupling changes its dimensions and compresses all joints with a high degree of sealing, which prevents the ingress of foreign bodies and moisture and provides greater electrical strength. These include couplings STp, STpM and others.
1 - hose, 2 - screen mesh, 3 - hose with a screen layer, 4 - insulating cuff with a screen layer, 5 - lining cuff, 6 - regulator plate, 7 - bolted connector, 8.10 - regulator tape,
9 - core tube, 11 - high-voltage glove, 12 - ground wire, 13 - spring, 14 - grater
15,16 - sealant tape
Figure 58 - Modernized heat-shrinkable sleeve 10 STpM for cables with BPI for 10 kV
Cold shrink sleeves are made on the basis of silicone or special EPDM (EPDM) rubber. (Ethylene Propylene Diene Monomer - E tylene-propylene-diene-modified rubber). They soften mechanical effects, are not afraid of the influence of moisture, aggressive acidic and alkaline environments¸ of sunlight. The sleeves keep the cable flexible and allow for slanting due to its locking properties.
The cold shrink sleeve has a silicone or rubber (EPDM rubber) body pre-stretched onto a spring coil that is removed during installation. After removing the helix, the sleeve shrinks easily, tightly wrapping around the cable and ensuring its sealing. The use of cold shrink sleeves also makes it possible to refuse the use of heating devices during installation work.
1-cable sheath, 2-shield tie, 3-silicone glove, 4-tube, put on the core, 5-insulation with sealing tape, 6-lug
Figure 59 - Cold shrink end sleeve for cable with XLPE insulation
Comparison of heat shrink and cold shrink. Cold shrink sleeves and heat shrink sleeves differ in their application, installation methods and physical characteristics. Externally, cold shrink and heat shrink sleeves are similar. Both types of couplings are used in the insulation, connection and termination of electrical cables for voltages up to 10 and up to 35 kV. The difference lies in the difference between the two technologies.
Heat shrink technology requires a heat source. The quality of installation in this case depends on the qualifications of the installer and the installation conditions. Uneven heating, which may be associated with limited working space or with limited access to the entire surface of the coupling, can lead to uneven insulation thickness. The use of an open flame requires special care in terms of damage to the cable or surrounding equipment, as well as a special permit for hot work. When installing a heat-shrinkable sleeve, the cable sheath heats up and the polyethylene softens. Overheating of the cable can lead to melting of the insulation and to a decrease in the insulation resistance. Another specific feature of heat shrinkage is the thinning of the insulating layer in places where the diameters differ when the sleeve shrinks on uneven surfaces. The softened material flows off this area, resulting in a thinner insulating layer there.
The installation of cold shrink sleeves is carried out without heating by removing the cord, without the use of any tools. In this case, the sleeve fits tightly on the cable, providing electrical insulation of uniform thickness.
Heat shrink materials and cold shrink materials react differently to the influence of temperature. Silicone and EPDM rubber tolerate temperature changes better and change their shape better with temperature fluctuations than heat-shrinkable materials, so they retain better tightness.
Due to these differences, silicone sleeves are recommended for installation outdoors, above the ground on cables of various voltages, as well as in conditions of extreme temperature changes. EPDM rubber products are best used underground, especially for installation work in cable ducts, as they require UV protection measures.
Cable termination produced before the installation of couplings and terminations. It consists in successive stepwise removal of protective covers, armor, sheath, screen and cable insulation over a certain length. The dimensions of the cut are determined according to the technical documentation, depending on the design of the cable and the coupling (terminal) mounted on it, the cable voltage and the cross section of its cores.
Starting to cut the end of the cable, check the absence of moisture in the paper insulation and cores. If necessary, remove existing wet insulation, excess length of ends, areas under sealing caps and end cable grips, as well as those passing through the cheeks of the drums. Defective places of the cable are cut off with NS sector scissors (Fig. 18, a).
Cutting the cable begins with determining the installation locations of the bandages, which are calculated by the formula: A \u003d B + O + P + I + G. At the end of the cable, measure distance A (Fig. 19, a) and straighten this section. Next, the resin tape is wound up (see Fig. 18, b) and a bandage is applied (see Fig. 18, c) from two or three variants of galvanized steel wire manually or using a special device (kletnevka). The ends of the wire are grasped with pliers, twisted and bent along the cable.
a - cutting the end of the cable with scissors NS; 6 - Resin tape winding; v- the imposition of a wire bandage; G- notching armor; d, e - removal of armour, yarn, cushion and cable paper
Rice. 18. Technology for cutting the ends of cables, applying bandages and removing covers
The outer cable cover is unwound to the installed bandage and is not cut off, but left to protect the armor stage from corrosion after the coupling is installed.
A second bandage is applied to the cable armor at a distance B (50-70 mm) from the first wire bandage. When installing cast-iron connecting and branch couplings and end fittings in steel funnels, the armor section is used to seal their necks, therefore, size B is increased to 100-160 mm. Along the outer edge of the second bandage, the upper and lower armor bands are cut with an armored cutter or a hacksaw (no more than half of their thickness), then the armor is unwound (see Fig. 18, d, e), broken off and removed.
Next, the pillow is removed (see Fig. 18, e). To do this, cable paper and bituminous composition are heated by the fire of a propane torch or blowtorch. The cable sheath is cleaned with a cloth soaked in transformer oil heated to 35-40 ° C.
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To remove the shell at a distance of 50-70 mm from the cut of the armor, ring cuts are made. In cast-iron couplings and end steel funnels, the shell section is used only for connecting the grounding conductor, therefore, the specified distance is reduced to 20-25 mm (see Fig. 19, a).
a - with belt paper insulation; b- with plastic insulation; 1 - outer cover; 2 - armor; 3 - shell; 4 - belt isolation; 5 - core insulation; 6 - cable cores; 7 - bandage; A, B, I, O, P, G and W - cutting dimensions
Rice. 19. Cutting the ends of a three-core cable.
When marking lead sheaths (Fig. 20, a), stake cuts at half the depth are made with a fitter's (Fig. 20, b) or a special knife with a cutting depth limiter (Fig. 20, c). From the second annular cut at a distance of 10 mm from one another (Fig. 20, e, f), a strip of the shell between two cuts is grasped with pliers and removed (Fig. 20, i). The rest of the shell is moved apart (Fig. 20, j) and broken off at the second annular incision. Between the first and second annular cuts, the shell temporarily remains. It protects the insulation from damage when the wires are bent.
For cables with an aluminum sheath, the cuts are made with an NKA-1M steel knife with a cutting disc (Fig. 20, d). A screw incision is made from the second annular incision (Fig. 20, g). Removal of the corrugated aluminum shell is carried out after its incision at a distance of 10-15 mm at the protrusion of the corrugations. Further, the cable cores are released from the belt insulation and gradually bent according to the pattern. Then they prepare a place for connecting the ground (Fig. 20, a, b).
To connect cable cores to the contact terminals of electrical devices, they are terminated with lugs fixed on the cores by crimping, welding or soldering. Termination of single-wire cores can also be performed by forming a tip from the end of the core. The connection of cable cores in couplings is carried out in connecting and branch sleeves by crimping, welding or soldering.
The technology of joining aluminum conductors by pressing is shown in fig. 22, a-z.
The ends of aluminum sector conductors are rounded before pressing: multi-wire - with universal pliers, single-wire and combined - with a special tool ISK or KS, as well as a tool included in the NISO set.
When crimping, the tip or sleeve is put on the core (the core should enter the tubular part of the tip until it stops, and in the sleeve the ends of the cores should rest against each other in the middle of it), installed in the pressing mechanism, preliminarily retracting the punch.
 |
| m |
a- markup; b, c - circular cuts in lead sheaths; G - circular cuts of aluminum shells; d, c ~ longitudinal cuts of lead sheaths; w - incision of the aluminum shell along a helical line; h, m - cuts in plastic shells; and, to- removal of lead sheaths;
l - removal of aluminum shells; n - removal of the corrugated aluminum shell
Rice. 20. Cable sheath removal operations:
The operations of connection and branching by direct soldering of the treated ends of the cores are shown in Fig. 23, a. The cores 1 are inserted into the molds (sleeves) 2 so that their joint is in the middle of the mold (for cores with ends cut at an angle of 55 °, the gap between the ends is left about 2 mm). Detachable molds are fastened with bandages or locks, and the gaps between the core and the mold are sealed with asbestos cord 7. For a more complete filling with solder, the molds are placed in a horizontal position, protective screens are put on the cores 5. When connecting the cores with a cross section of 120-240 mm 2, coolers are additionally installed.
a - wire bandages; b- soldering; 1, 3 - bandage at the ends
shell and outer cover; 2, 4 - bandage for soldering the ground conductor
Fig. 21. Ways of fastening the ground conductor to a metal sheath
The mold (sleeve) is heated by the flame of the burner 3. At the same time, a stick of solder 4 is introduced into the flame, the melt of which is stirred with a stirrer 8 until the mold is completely filled and slags are removed. After that, the heating is stopped. The solder is compacted by light tapping on the mold. The crucible 11 (Fig. 23, b) during soldering is poured from the ladle 9 with pre-molten solder, set at a certain distance in order to exclude additional heating of the core insulation. Tray 10 is placed between the crucible and the place of soldering, along which the excess will drain (the tray should not touch the core insulation).
The technology for isolating the junctions and terminating the cable cores with paper rollers and rolls is shown in Fig. 24, a-f. After connecting the cores, the paper insulation is washed with an impregnating composition heated to 120-130 ° C. Then the upper coloring tapes are removed from the insulation of the cores: the insulation is cut in steps in a section 16 mm long - for 6 kV cables and 24 mm - for 10 kV cables. The width of each step is 8 mm, eight tapes of paper insulation are cut off at each step.
Restoration of the insulation of bare sections of the cores is carried out with rollers 5 mm wide (winding is done to the outer surface of the connecting sleeve or factory insulation, depending on which has a smaller diameter). Further insulation is carried out with rollers 10 mm wide. Periodically insulated cores in the process of winding are scalded with an MP impregnating composition heated to 120-130 ° C. Further insulation is performed in cylindrical rolls up to 300 mm wide, depending on the brand of the coupling.
a - cleaning the inner surface of the sleeve; 6~ lubrication of the inner surface of the sleeve; v - the ends of the cores with the insulation removed; G - stripping the ends of the veins; d - lubrication of the cores with quartz-vaseline paste; e- putting on the sleeve on the cores; well- pressing of a vein; h -~ measurement of residual thickness at the pressing point
Rice. 22. Technology of joining aluminum conductors by pressing.
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