Antipyretics for children are prescribed by a pediatrician. But there are situations of emergency care for fever, when the child needs to give the medicine immediately. Then the parents take responsibility and apply antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? Which medications are the safest?
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Classification of cable joints.
Cable coupling- A device intended for connecting, branching cables and for connecting them to electric appliances or overhead power transmission lines.
Connecting cable coupling - a device designed to connect the cables, ensuring the reliability and integrity of the connected name.
Retainer cable clutch- a special coupling designed to connect the cables and prevent the drainage of the cable mass when laying cables on the tracks with differences in height.
Cable splice - a special coupling designed to connect the branch cable to the main cable line.
End Cable Clutch - A device designed to connect cables to external and internal installation devices or overhead power transmission lines.
Cable termination - a device designed to connect cables to the internal installation. Cable termination does not have a special protective housing.
Types are divided into brands, depending on their design. Depending on the dimensions for different cable sections, the brands of couplings are classified according to the mark size. A barbed wire, a coupling sleeve, with an epoxy housing having a longitudinal section in the vertical plane, a 1 kV CMV has two markers: SEV-1 and SEV-2.
End cable glands. The existing designs of the end cable fittings are not universal, each is designed for a specific application. Unlike the coupling end couplings, there is only one environment for accommodation - air both indoors and outdoors.
For cables with paper impregnated insulation for voltage up to 1 kV, end mast clutches ZKM and 4KM and epoxy KNE (Figure 11) are used, for cables with plastic insulation for voltage up to 1 kV - elastomeric couplings PKNR or cast iron mast clamps ZPKMCH, 4PKMCH.
Cable splices. In the approach to consumers, tap-iron cast iron or epoxy OEs are used. There are several versions of couplings: ОЧт - cast-iron T-shaped for a branch of a cable at an angle of 90 °; OCHU - cast iron Y-shaped at an angle of 30 °; OCHK - cast-iron cruciform for the branch of two cables. All couplings provide for open cable cutting and subsequent pouring with bitumen or epoxy compound (for OE couplings).
Fig. 1. End couplings: a - masted CM; 1 - cover; 2 - insulators.3 - grounding conductor; 4 - lead cuff; 5-clutch housing; 6-contact rod; b-terminal NOEC; 1 - cable lug; 2-bushing insulator; 3 - clutch housing; 4 - bracket for fastening; 5 - grounding drive; 6 - reeling of cotton strips 
Fig. 12. KEE end epoxy seal:
1 - the tip; 2 - bandage; 3-tube; 4 - insulation of the core; 5 - epoxy compound; 6 - cable armor; 7 - grounding conductor; 8 - rewinding; 9-belt insulation; 10 - case of closing
End cable ties.
For most types of termination, cable assemblies are not required.
For cables with paper insulation for a voltage of up to 1 kV, clutches of the type КВР or heat shrinkable polyethylene gloves ZKVTp, 4КVТп are used.
Terminations with a casing made of epoxy compound and tubes for sealing the veins of KVE (Figure 12) are designed for termination of cables for 1 kV voltage indoors, as well as for outdoor installations, provided that the seal is protected from direct exposure to atmospheric precipitation, dust and sunlight. These seals are installed in any position and can be used in a chemically active medium. In accordance with the necessary degree of protection against the penetration of moisture from the surrounding air, KVE seals use the following versions:
КВЭтв - with heat shrinkable PVC pipes; KVEK - with organosilicon tubes; КВЭн - with tubes from nayrit rubber; KVET - with three-layer tubes. Terminations with heat-shrinkable tubing in wet and damp areas are used with additional winding of self-adhesive tapes under the tubes.
The end epoxy imprints of KVEP are used in damp and especially damp rooms for the termination of three-core cables. These seals are installed in a horizontal or vertical position and at any angle of inclination.
Terminations from self-adhesive KVsl tapes are used for termination of paper-insulated cables with aluminum or copper conductors of up to 240 mm2 cross-section in dry premises with a difference in levels between the highest and lowest points of the cable route up to 5 m. They can be used with a level difference of up to 10 m. Terminations in rubber gloves CWR are used to terminate cables with paper insulation for voltage up to 1 kV in dry and wet rooms with a difference in levels for the bottom seal of more than 10 m. They are installed in any position.
The end seals of the KVEO with the rewind from the cotton tapes smeared with epoxy compound,
used to finish single-core cables voltage up to 1 kV for the same conditions as for the embedding of KVE.
For cables with plastic insulation for installation inside the premises, a terminal closure of the PCB type is used, and in the damp premises - PCVE (Figure 13).
Dry cable sealing with paper insulation using polyvinylchloride tape, PVC pipes and varnishes is made as follows.
Measure the necessary length of the cutting.
From the end of the cable, the shell of the armor is removed and at a distance of 30 mm from it a lead (or aluminum) shell and a general insulation.
Preliminary on the armor impose a bandage of soft wire with a diameter
1 mm or of roofing steel and wipe the surface of the lead or aluminum cable sheath moistened with gasoline or kerosene until completely clean.
Operations to cut the lead shell are performed with a cable knife of the type PK-1. At a distance of 2 mm from the cut-off point of the armor, make one ring cut on the shell and, after retreating from it by 10 mm, the second. From the second annular notch and to the end of the cable make a longitudinal incision of the shell. First, remove a portion of the lead shell enclosed between the longitudinal incisions, and then remove it completely, starting from the end of the cable, to the second annular notch.
The aluminum shell is removed with a special knife. At first, make annular incisions, and then cut from the second annular notch along a screw line and remove the sheath before the second annular cut.
When making cuts, care should be taken not to cut the shell.
The depth of the incision should not exceed 2/3 of the thickness of the shell.
In order to protect the insulation against possible ruptures, the annular belt of a lead or aluminum shell enclosed between two annular
cuts, removed only after the execution of "locks" on the veins and putting on them polychlorvinyl pipes.
The total insulation from the end of the casing to the end of the cable is removed by unwinding and breaking off of its individual bands.
After cutting the end of the cable, the insulation of each core is removed for a length of 10-15 mm, retracting 15 mm from the second ring cut.
The bare area of the veins and their insulation are degreased by wiping with a clean rag soaked in gasoline. Then the lower part of the insulation of veins and the bare area is covered with polychlorvinyl nail varnish No. 2, after which the locks are carried out, tightly wrapping the adhesive polyvinylchloride tape on the bare section of veins. The winding of the "locks" should cover the bare area and go to the insulation of the veins of 5 mm on each side. The thickness of this winding should provide a tight overhang on it polyvinylchloride tube.
At the end of the winding of the "locks" polyvinylchloride tubes are pushed onto the conductors. Then the veins are slightly diluted, after which the annular band of the lead or aluminum sheath closing the stage of common insulation is removed. On the edge of the insulation, a band of harsh threads is applied, and its surface (as well as the stage of the shell) is degreased with a cloth dampened in gasoline.
The space between the cores in the spine of the seal is filled with polyvinylchloride varnish No. 2, and the veins are pulled into the bundle by several turns of cotton tape. Then, with a sticky polyvinylchloride tape, a winding covering the common insulation, the section of the wires and the cable sheath is performed. The tapes of this winding should penetrate the shell at a length of not less than 22 mm and cover the common insulation and polyvinylchloride tubes at a length of 40 - 45 mm. The winding is carried out in 5 - 6 layers of tape, wound with tension and 50% overlapping coils. The surface of the winding is covered with polychlorovinyl lacquer No. 1. Over the total winding (over its entire length) a tight band of twisted twine with a diameter of 1 - 1.5 mm is applied, which is covered with asphalt insulating varnish or varnish No. 1154.
To connect to the terminals of the device, the ends of PVC tubes and the bare wires of the cable leaving them are wound with a sticky PVC tape with the tape coming on the bare core and the tube.
The winding of the tape is covered with polyvinylchloride lacquer No. 1.
[BCH 116-65]
The terminations on these cables are carried out with polyvinylchloride (for cables with PVC insulation) or polyethylene (for cables with polyethylene insulation) tapes by special instructions.
Terminations with a plastic sheath are determined by the operating voltage and cable design. Cables with a voltage of 6 kV over the insulation of the conductors have semiconducting and metal screens, cables with a voltage of 10 kV have a semiconducting screen over the stripped conductor and a separate plastic sheath for each conductor, cables for 1 and 6 kV are enclosed in a common hose. Terminations on these cables are carried out with the help of polyvinylchloride (for cables with PVC insulation) or polyethylene (for cables with polyethylene insulation) tapes by special instructions. The peculiarity of these closures is that strips of semiconducting and metallic screens are wound off each strand: In this case, the tapes at the conductive shield are cut off at a distance of 40 mm from the cutoff of the shell, and the metal screen tapes from all three phases are soldered to the ground conductor. On cables with a voltage of 10 kV, in addition, a conical winding is made of an adhesive tape, over which, starting from the cutoff of the shell, the ribbons of the semiconducting screen are wound, cutting them off at the top of the reel cone.
End sealing is performed, as a rule, dry or in funnels. A dry end seal is made without casting compounds, using polyvinylchloride tubes, insulation tape, insulating varnishes and other materials. The termination of the cable in the funnel - metal or plastic - is filled with casting compounds.
Cutting the end of the shielded. Terminations in plug connectors are cylindrical type PPH and PPM (old designation SR and SSR) and rectangular types A. Connectors type PPH and PPM perform on shielded and unshielded, and connectors type A - only on shielded cables and wires.
The terminations in the steel funnel of the KVB filled with bituminous mass are used in cases where it is difficult to obtain embeddings of other more modern designs at a level difference of not more than 10 m in dry and damp areas, with the exception of hot and chemically active medium.
End fences are performed in funnels or dry.
Terminations can be used in closed rooms, both heated and unheated. Funnels of control cables, located in open substations and in damp areas, should be protected from direct exposure to rain and snow. Usually in such cases, cabinets are used to house control equipment.
Fixing KVsl. Termination in heat-shrinkable polyethylene gloves is used for the termination of three-core (ZKVTp) and four-core (4KVTp) power cables with paper insulation up to 1000 V and consists of a heat-shrinkable polyethylene glove, to the fingers of which are glued heat-shrinkable polyethylene tubes for sealing the veins. Shrinkage of pipes is carried out evenly by heating (flame of the gas burner) starting from the spine of the seal.
Termination in rubber gloves CWR has the same purpose as the sealing of the KVTp, and consists of a rubber glove, to which fingers are glued tubes of nai-rub rubber to seal the veins.
The end-to-end seizures largely determine the quality electrical wiring.
Termination of epoxy compound. The termination in the epoxy compound is carried out as follows. After the usual cutting of the cable end, the previously cleaned and degreased areas of waist paper insulation, lead or aluminum sheath, and also the diluted cable cores are wrapped by three layers of cypernose tape coated with each layer with an epoxy compound. Each layer of cypernose tape, covered with epoxy compound, is a sealing shell of the seal. The dimensions of the cutting and shaping are determined by the cross-section and voltage of the cables.
Terminations in rubber gloves are used on cables with paper insulation up to 10 kV, laid inside the premises.
The end seal includes the cutting of cables and wires and their subsequent sealing.
Terminations can be dry, in funnels or using epoxy compound. For dry sealing, insulating pipes, tapes and varnishes without casting compounds are used. When embedded in funnels, they are flooded with special compounds along with the cable section. When encapsulated with an epoxy compound, the molten mass is poured into a metal or cardboard mold that is removed after the compound has solidified. Dry rooms are usually used termination.
Dry termination of the cable end with polyvinylchloride tape. Endings made of epoxy resins are small in size; in addition, they have great electrical and mechanical strength and are easy to manufacture. On the end of the cable with the diluted veins covered with an additional isolation, put a temporary conical metal funnel and poured it with the warmed up epoxy resin with an admixture of the hardener. After the composition has hardened, the metal funnel is removed. The toxicity of epoxy resins requires caution when handling them.
Terminations serve to seal and isolate the ends of the cable before they are connected to the electrical equipment. They are made of epoxy compound, dry, in a steel funnel and in other ways. In Fig. XIV.9 6 shows the termination of the epoxy compound. In this type of sealing, the sealing of the ends of the cable with paper insulation from leakage from the paper of insulating oil is achieved by wrapping the cable cores in several layers with a kiper tape and coating each layer with an epoxy compound. The end of the cable with the tips prepared in this way is put on a removable form and filled with an epoxy compound. In order for the mold to be easily removed after solidification of the compound, inner surface it is lubricated with transformer oil.
Terminations are carried out after the termination of a lining and fastening of cables and wires. Seals produced outdoors should be carried out in tents heated during the cold season. When the cable is terminated, breaks until the work is completed is not allowed to avoid penetration of moisture under the winding or insulation.
Termination with the use of polyvinylchloride tape and varnishes in damp and wet rooms are unreliable. The most common defects in the installation of fittings are a break in the insulation of the veins in the spine and the breakdown of the seals due to their incorrect application.
Universal sector scissors NUSK-300. End fences are performed in funnels or dry. The termination of the cable in the funnel - metal or plastic - is filled with casting compounds. A dry end seal is made without casting compounds, using polyvinylchloride tubes, insulation tape, insulation varnishes and other materials. As a rule, dry end fittings are performed in rooms of all classes.
Fastening of cables with clamps in a vertical box. | Attach the protective tube to the box. End sealing is performed dry or in funnels. A dry end seal is made without casting compounds, using polyvinyl chloride tubes, insulation tape, insulation varnishes and other materials. The termination of the cable in the funnel - metal and plastic - is filled with casting compounds. Dry endings are performed in dry rooms of all classes.
Dry end cable sheathing with rubber insulation. The end fences in the funnels are performed only on cables laid in especially damp rooms and on external installations.
End fittings used four types: epoxy funnel, rubber glove, bitumen funnel and dry cutting. To investigate the effect of insulation thickness on the cable ignition process and the type of shell on the occurrence and spread of fire, cables of various voltages and with various shells were taken.
Terminations with a casing made of epoxy compound and tubes for sealing the veins of KVE (Figure 7.12) are designed for termination of cables for 1 kV inside the premises, as well as for outdoor installations, provided that the seal is protected from direct exposure to atmospheric precipitation, dust and sunlight. These seals are installed in any position and can be used in a chemically active medium.
Termination in lead glove KBC. Terminations in lead gloves of the KBC brand (Figure 133) are used for termination of three-core cables for voltage up to 10 kV indoors, as well as in outdoor installations, provided protection of the seal against direct effects of atmospheric precipitation, dust and sunlight.
The termination of the internal installation in the lead glove KBG (see Figure 133) is a glove with a cylindrical bottom soldered to the cable sheath 10 and three fingers in the upper part, sealed at the place of passage of the conductors by winding 6 belts and a tight band 2 of twisted twine. The place of insertion of the veins in the cable lugs / has the same winding. LHM-105 with a thickness of 0-2 mm, each layer of which is covered with varnish EA-4 or with a capon-glyftal varnish. The internal filling area is poured by bituminous composition through a hole, temporarily cut from the side of the glove, to be sealed after the end of this technological operation.
General view of the pipeline with an electroheating element wound on it. Terminations (switching points) are pressed with silicone rubber.
Repair molds installed in case of leakage. Terminations made of epoxy compound are inspected and, when leakage of the impregnating composition is detected, measures are taken to restore the tightness. Its violation occurs usually as a result of non-compliance with the instructions for degreasing the surface and other technological instructions when installing end seals.
Termination of 10 kV cables in a steel funnel. Cable termination in lead glove. The end fences in the steel funnels of the KVB (Figure 138) are used for termination of cables with voltage up to 10 kV inside dry premises.
Terminations in lead gloves KBC (Figure 139) are used for the termination of three-core power cables with a voltage of up to 10 kV indoors, as well as in outdoor installations, provided full protection of the seal from direct atmospheric precipitation and dusting. Glove 3 is a lead cap with three lead fingers, which is put on the split end of the cable. Preliminary, the cores 5 of the cable are additionally wound with a lacquer cloth and covered with c-apone-glnftalev lacquer. Place the veins from the fingers of the glove and insert them into the tips additionally reeled with a lacquer fabric and sealed with a special winding 8 of twisted twine. Preliminary on the veins are soldered or welded, or press the tips. The inner cavity of the glove is filled with a cable mass MB-60 or MBM. A grounding conductor is soldered to the shell and steel armor.
Terminations in rubber gloves КВР are intended for termination of power cables with voltage up to 6 kV indoors.
Terminations made of polyvinyl chloride-nylon KVV can be mounted on cables with paper insulation up to 10 kV inside the premises, as well as in outdoor installations, provided that the seals are completely protected from direct exposure to atmospheric precipitation, dust and sunlight.
Terminations are performed after the termination of the laying and fixing of cables and wires and serve to seal the ends of the cables, insulation of the veins of cables and wires in the cutting site, securely connect the conductors to the terminals and contacts, mark the veins of cables and wires and ground the sheath and armor cable.
Terminations can be dry with polyvinylchloride tubes, insulation tape, insulation varnishes and other materials without the use of casting compounds, they can also be in metal or plastic funnels filled with casting insulation.
Terminations in lead gloves such as KVS have long been used in electrical installation practice.
Termination in a lead glove with the winding of the veins with a halfpenny chloride tape. Dry termination with rewind on a vinyl chloride tape. Terminations in rubber gloves (Figure 186) are widely used.
End clutch of outdoor installation of PCNE type with voltage up to 1 kV. Terminations in lead gloves such as KVS are cast in special forms of lead gloves with three fingers through which the ends of the cable veins are pulled.
The end seal consists of the cutting of cables and wires and their subsequent sealing. When cutting, the veins of cables and wires are released from the outer covers, armor, shell and waist insulation. Subsequent sealing consists of hermetic sealing of casings, insulation of cores, connection of earthing wires to armor and metal sheaths, electrical termination and marking of cores.
Terminations can be dry, in funnels or using epoxy compound. For dry sealing, insulating pipes, tapes and varnishes without casting compounds are used. When embedded in funnels, they are flooded with special compounds along with the cable section. When encapsulated with an epoxy compound, the molten mass is poured into a metal or cardboard mold that is removed after the compound has solidified.
Terminations are carried out after the termination of a lining and fastening of cables and wires. Seals produced outdoors should be carried out in tents heated during the cold season. When terminating the cables, breaks are not allowed until the work is completed to prevent moisture from entering under the winding or insulation.
Cable termination in lead glove. Terminations in lead gloves can be used for cables with non-sticking impregnating composition. Glove filling in this case is produced by bituminous masses MB-70 and MB-90 without the addition of mineral oils.
Dimensions of removable molds for epoxy seals, mm (7 - 22.) General view of the termination of the epoxy compound type 4E./-the tip for the fourth core .-- 2 - the tip for the core .-- 3 - wound with a tape with an epoxy compound or nylitic Termination from epoxy compound is applicable for the termination of cables with non-sticky impregnating composition.
Dry cable sealing with rubber, polyvinyl chloride or polyethylene insulation of cores using PVC pipes and tape. The choice of polyvinylchloride tubes. Termination of cable with rubber, paper, polyvinyl chloride or polyethylene insulation of cores with the use of epoxy compound. Terminations and connections of cables and wires must ensure the sealing of the cable and prevent penetration of moisture under the cable sheath and insulation of the cores, as well as leakage of the oil-and-oil composition of paper-insulated cables. At the same time, the insulation quality of the end seal should not be less than the insulation of cables and wires. When the cable is terminated, its cutting, proper sealing, marking and grounding of the metal shell and armor are performed. In addition, termination, wire routing and marking of cores, as well as reliable connection of junction boxes, switchboards, panels, instruments and other means of automation to the terminals are performed.
Terminations in plug connectors must additionally provide a continuous electrical circuit shielding sheaths of cables or wires with metal connector housings; fastening of cables or wires in the connector housing, which preserves the integrity of the connection of the conductors with the contacts of the connector; permissible bending radii of cables and wires at the junction and dismemberment of the plug connector.
Epoxy response coupler type OE for cables up to 1 kV. The termination is carried out to seal the cable in the immediate vicinity of the place of connection of its conductors to apparatuses, buses of switchgears and other elements of the electrical installation.
Cable passage in boxes from the street. Terminations and connections of cables and wires must ensure the sealing of the cable and prevent penetration of moisture under the cable sheath and insulation of the conductors, as well as the protection of the insulation of cores, freed from the factory shells, from the influence of the external environment. The quality of insulation of the end seal should not be less than the quality of insulation of cables and wires. When the cable is terminated, its cutting, proper sealing, marking and grounding of the metal shell and armor are performed. In addition, termination, wire routing and marking of cores, as well as reliable connection to junctions of junction boxes, boards, panels, devices and other automation means are performed.
KVEhD, KVEP and KVEZ end clamps are installed in the same way as KVEN cladding, but their installation has some features, the description of which is given below.
KVEhD, KVEP and KVEZ end clamps are installed in the same way as the KVEN cladding, but their installation has some features. Some other materials are used, the methods for removing the cores of the cable from the epoxy housing or, in part, the technology of mounting the end seal.
The end caps of the KVB in steel funnels filled with bituminous mass are widely used even now, although they are replaced by the methods of cable sealing with the use of epoxy compound, polyvinyl chloride tape and rubber gloves gradually described in this chapter.
The end seal of the sleeve consists of two separate parts: a nipple (sleeve) that is inserted into the sleeve, and an outer part of the seal that connects the sleeve to the working unit or other sleeve.
At the beginning and end of the cable line, the cable core must be connected to the appropriate power line devices. For termination of cables outside the premises, cable couplings are used, and indoors - end fittings.
End Couplings. Before installing the end sleeve from the end of the cable, protective covers and a metal sheath are removed at a certain length. Next, a cable outlet is mounted on the cable core.
In places where the screen breaks through the cable insulation, additional insulation is placed in the end couplings. Additional insulation in the sleeves of cables with paper impregnated insulation is done manually in the form of winding rolls of pre-impregnated cable paper. In couplers for voltages of 1-35 kV, paper rewind is successfully replaced with cast epoxy insulation.
In the clutches of cables with plastic insulation for voltages of 1-10 kV, additional insulation is superimposed on the cable in the form of winding from self-adhesive tapes, in clutches for voltage 35 kV and higher, plastic parts or additional insulation made of polyethylene or ethylene-propylene, which is superimposed on the cable by extrusion .
To protect the cable insulation and additional insulation of the coupling from moisture and contamination, the cable end with the winding is placed in a porcelain insulator.
The space between the winding and the porcelain insulator is filled with special insulating compounds: bitumen or oil-and-oil compositions (for couplers for voltage up to 35 kV), cable oils (for oil-filled cables). Terminations of cables with plastic insulation can be filled with silicone fluids, etc.
Figure 1 shows a three-phase end clutch for cables with voltages of 6 and 10 kV, and in Fig. 2 - an end epoxy coupler for 35 kV cables.
Fig. 1.
for cables 6 and 10 kV:
1 - lead cuff; 2 - insulator; 3 - the tip; 4 - contact head; 5 - copper cap; 6 - brass semicircle; 7 - housing; 8 - grounding wire; 9 - cone
Fig. 2.
1 - contact tip; 2 - cover; 3 - insulator; 4 - the cone; 5 - insulator; 6 - flange; 7 - rewinding of glass wool; 8 - filling with epoxy compound
Terminations. The design of the end sleeves is greatly simplified if they are applied to a voltage class of up to 10 kV and are located in enclosed spaces. In these cases, for termination of the cables, so-called end seals are used. Figure 3 shows the design of the heat-shrinkable end clamp (seal) of the internal installation TERMOFIT-10KVTP, produced by ZAO "TERMOFIT", St. Petersburg.
Fig. 3.
Terminations TERMOFIT-10KVTP are designed for termination of three-core power cables with paper impregnated and plastic insulation with a voltage of 6-10 kV. They are designed for indoor installation of all categories of humidity. When installing the above-mentioned seal on cables with paper impregnated insulation, the maximum allowable level difference is 25 m. The permissible ambient air temperature during installation and operation of the coupling is from -50 to +60 ° C. The installation is based on the heating (shrinking) of parts from the modified polymer. Heat-shrinkage is performed by a gas burner or a high-temperature dryer. When the temperature reaches 120-140 ° C, the part is compressed in diameter (shrinks) before contact with the insulated surface. When it cools down to the temperature of the surrounding air, its new shape remains. The seated parts must adhere to the elements of the cable and do not have wrinkles and wrinkles.
Cable terminations
In distribution devices for termination of cables in the places of their connections use different types endings.
Terminations for power cables with cardboard and plastic insulation must be made in accordance with the technical documentation.
Dry endings with polyenyl chloride strips, as well as endings in the form of rubber gloves, can not be used in wet and damp rooms, which include urban network substations and complete transformer substations of external installation.
For the termination of cables with a voltage of 1 - 10 kV, use end caps of KVE with epoxy compound housing, ordinary in installation and non-hazardous in the fire relation.
End seal of KVED
End internal epoxy seal KVEd with double-layer tubes. The distance between the tubes at the outlet from the epoxy housing for cables with a voltage of 10 kV should be more than 25 mm. At the end of the KVED installation, double-layered tubes are laid on the insulation of the veins, the outer layer of which is made of polyester, and the inner layer is made of polyvinyl chloride.
To increase the density of the rootlets, the cuts are poured with an epoxy compound. To avoid penetration of the impregnation of the insulation of the cable between the layers of the tube make a step (cut off the upper polyethylene layer) at a distance of more than 20 mm, place treated with a special glue PED-B, which has good adhesion (adhesion) to epoxy. This glue lubricates the inner surface of the upper end of the tube, which is put on the tip, a band of twisted twine is applied over the tube in this place. The mounted seal is painted with a special enamel.
KVEN end seal
The end seal of KVEn differs from KVEHD in that instead of double-layer tubes for sealing the insulation of the veins, pipes made of nylitic rubber are used. These pipes more terribly protect the insulation from water than two-layer, and therefore they should not be used in damp areas.
Termination of the CAB
Extensive distribution found the end seals of the internal installation in the iron funnels of the KVB (tailings internal bituminous endings). The iron funnels of the end fittings can have a round and round shape. In these endings over the insulation of the cable veins, 50% overlapping of 3 to 4 layers of insulation tape (sticky polyvinylchloride or lacquer cloth with varnish lining) is wound over, and at the place of installation of porcelain bushings for their tight fit make a conical winding. To ensure that the bituminous mass does not flow, the funnel is rewound from the resin band at the mouth of the funnel. The funnel and cores of the cable are painted with enamel. At a voltage of up to 1 kV, end fittings are installed without porcelain sleeves and covers.
Repair of cable end fittings
When repairing end-to-end termination of power cables is usually performed during the current repair of substation equipment. When repairing the terminations of power cables, inspect the correspondence of the distances from the phases to the "ground" to the values indicated in the PUE. At a voltage of 6 kV this distance should be more than 90 mm, at 10 kV - 120 mm.
Surface finishings of power cables are carefully cleaned from dust. At external inspection inspect integrity of tips, their conformity to a section of veins of a cable and quality of the soldering (welding, опрессовки). The discovered shortcomings save.
At iron funnels with voltage 6 and 10 kV wipe and inspect porcelain bushings. If they have chips and cracks, they are substituted. This work is done by cable operators, since it is necessary to dismantle the seal.
If the casting mass is not enough, it is added. If the phase isolation is broken, it must be returned, after which the cable cores and the shell of the funnel are covered with enamel paint.
Terminations from epoxy compound are inspected and, when leakage of impregnating composition is detected, constructive measures are taken to restore the density. Its violation occurs usually as a result of non-compliance with the instructions for degreasing the surface and other technological instructions when installing endings of power cables.
In order to eliminate leakage of the impregnating composition at the entrance of the cable into the casing, degrease its lower part in a section of 40-50 mm and the same section of the cable armor with a rag soaked in acetone or aviation gasoline. The area of the armor (shell) is processed with a hacksaw blade, knife or ratfilem for the creation of a rough surface.
A two-layer rewind is applied to the defatted area from a cotton strip, lubricated with an epoxy compound, then a removable repair mold made of vinyl plastic, teflon, etc. is used. Forms from tin or cardboard are previously smeared with a narrow layer of grease, transformer oil or other substance to avoid adhesion of the epoxy compound , then poured with the same compound, from which the shell of the seal was made.
In case of a density violation at the outlet of the cable cores, a flat surface of the housing and outgoing sections of phases 30 mm in length are degreased from the housing. Install a removable repair form, filled with compound similar to the previous case.
When the density is disturbed on the cable cores, the warped surface area is degreased and a double-layer winding of cotton strips lubricated with an epoxy compound is applied. Likewise, the leakage of the impregnating composition is relieved if there is a violation of the density at the junction of the tube to the cylindrical part of the tip. In this case, in addition, a tight band of twisted twine with an epoxy compound coating is applied over the winding.
