Draka Industrial Cable GmbH

Transcription

1 A) Preparation of cable ends To enable the stranding of the cores after connecting main and earth cores, each of the cable ends to be connected are laid in a double loop with righthand turn and then fixed in a vice. Outer and inner sheath of the two cable ends have to be removed for the length shown by "a" and "b" of the table. The core ends have to be untwisted and the distance between the ends of the cores and the point where they enter the inner sheath has to be adjusted according to distance "b" of the table. The main cores are cut at one end according to length "c" of the table and at the other end in opposite sequence. The overlap of cores is necessary for the connection of the conductors. B) Connection of main cores View Cadweld instruction. Split Earth conductor: Butt welding. To bond the stripped conductor, use a thin wire and fix it at the end of the conductor. Both conductor ends have to be smoothed at the front side and spread with flux. Then heat the ends and cover them with silver sold. The hot ends have to be pushed together and soldered by using heat and silver sold. Eventually created bits and edges have to be removed with abrasive cloth. C) Renewal of core insulation To enlarge the contact area between existing insulation and the unvulcanised insulation material, the existing insulations are chamfered for a length of approximately 50 mm. This chamfering has to be done in such a way that the sheath of conductive rubber above the insulation is removed along approximately 10 mm from the end of the chamfering. The chamfered part of the insulation has to be roughened by means of an abrasive type and cleaned by a suitable solvent or with a mixture of gasoline (chemical grade) and Toluene (approx. 70/30). After approximately one to two minutes a tape of conductive rubber has to be wound tautly on to the conductor with an overlap of 50 %, beginning on one of the original layers of conductive sheath. The joints have to be smoothed with a warm knife. Above this conductive sheath and the chamfered part of the insulation non vulcanised Seite: 1

2 rubber tape (compound 3643) has to be wound tautly with an overlap of 50 % until the thickness of the insulation is reached. When the original core diameter has been reached, the connecting area should be smoothed with a warm knife. Conductive rubber tape is then firmly wrapped around the insulation, and the connection points are also smoothed out with a warm knife. Double-sided graphitized textile tape is wrapped over it, and a vulcanisation-proof plastic foil is added with 50 % overlap, starting at approx. 30 mm before the graphitized tape. The earth conductors are wound only with a conductive rubber tape. Then-follows the vulcanisation-proof plastic foil. After the cores have been prepared in this manner, vulcanisation follows in a mould of a vulcanising press at approx. 170 C. Vulcanising time is given in the table. The inner diameter of the mould must correspond to the core dia. D) Twisting of main cores at the connection area Remove the connecting area from the vice, and straighten the cable by removing the loops at both the ends. The cable will now turn, mainly in the connecting area, and the straight cores will twist to the left. E) Replacement of inner sheath The inner sheath ends are chamfered for a length of 40 to 50 mm and roughened with a rasp. The chamfered and roughened surfaces of the inner sheath are washed with a solvent. The remaining interstices of the twisted cores are filled up with strips of rubber mixture 3643 and the cable connection is then wrapped with rubber tape (compound 3643). The tape is approx. 40 mm wide and is wound tautly with a 50 % overlap, around the twisted cores and the chamfered part until the normal inner sheath diameter is reached. Afterwards the connection is wrapped with rubberized textile tape and vulcanization-proof plastic tape (50 % overlap) up to the outer sheath. Seite: 2

3 Vulcanization is carried out under a vulcanizing press using a suitably sized vulcanization mould. For vulcanization time at 1700 C, see table. The plastic foil is removed when the vulcanized area within the mould has cooled down. F) Replacement of the outer sheath The outer sheath ends are also chamfered for a length of 50 to 60 mm and then roughened with a rasp. The chamfered and roughened connection surfaces are cleaned with solvent. The outer sheath of the connection area is renewed by wrapping with tape of rubber compound 3859 (red). The connection area is wrapped with a plastic foil (50 % overlap), and the wrapping should continue 30 mm beyond the connecting area at both ends. Vulcanization is carried out like with the inner sheath in a mould under a vulcanization press. Vulcanization time at 170 C acc. to table. After cooling within the mould the plastic foil is removed. Components for cable joints can be supplied by us. When no vulcanisation press is available the following method with heating tape can also be used: Rubber tape wrapping to be covered with two layers of vulcanisation-proof plastic tape (90 % overlapping). Wrap one layer of textile tape on the plastic tape. Put aluminium foil of 0.05 mm thickness on the wrap and apply thermocouple to the middle of the wrap-connection. Wrap one layer of vulcanisation-proof plastic tape (50 % overlapping) on the aluminium foil including the thermocouple. The heating tape to be wrapped on top of hostaphan lies beneath the tape and not between two wraps. The ends of the heating tape to remain free. Entire length of wrap joint to be covered with a layer of glass fibre tape (50 % overlapping). Heating tape and thermocouple to be connected with the female plugs of temperature control device. The vulcanising time to count after reaching the correct vulcanising temperature 170 C, is about 10 min. more than in the table. After reaching the correct temperature, adjust and control vulcanising time required. After vulcanisation remove glass fibre tape and heating tape. The thermocouple provisionally to remain on the joint. After reaching temperature below 90 C remove the tapes etc. on top of the now vulcanised rubber wrapping. Seite: 3

4 Attention: For the renewal of the core insulation this method should only be used by experienced technicians. Mounting instruction for the splicing of High Voltage trailing cables Montageanweisung für Leitungstrossen Durchverbindung zweier Leitungsenden Tables Tabellen 1) Absetzlängen 1) removed lengths a Aussenmantel a outer sheath b Innenmantel b inner sheath c Adern c cores d Isolierung d insulation Seite: 4

5 Cross-section Length Spliced butt jointed Leiterquerschnitt Absetzlängen Stumpf- Spleiss m m² a b C1 C2 C3 C4 D Seite: 5

6 2) Vulkanisationzeiten 2) Vulcanisation time e Aderisolierung e core insulation f Innenmantel f inner sheath g Aussenmantel g outer sheath Cross-section Leiterquerschnitt Vulcanisation time Vulkanisationzeiten mm² e f g Operating Instructions for the Removal of the outer semi-conducting Rubber Screen from Trailing Cables Preparation of a cable termination includes removal of the outer conductive rubber screen around the phase core insulation, to a length complying with the required creeping distance (i.e. 175 mm for 11kV) Incise the semi-con rubber layer lengthwise into 3 or 4 stripes of the required length, taking care not to damage the insulation. At the end of the incisions i. e. 175 mm from the insulation edge, rub a circular groove down into the semi-con layer using abrasive band, after masking off the area to be rubbed with self-adhesive tape. Then warm up the incised area using a yellow propane burner flame. The operator needs gloves. Seite: 6

7 Now try to lift the edges of the incised layer by sliding in a rasp tangentially. When one layer has been lifted and slightly separated from the insulation, you can grip it and pull the section off completely. lf the edges are difficult to lift off from one side, try the other one. The direction of vulcanisation determines the direction of easy lift-off. Sometimes it is necessary to warm the layers up again, as a higher temperature facilitates the separating process. Carefully remove the rubber residues and black patches from the insulation by means of coated abrasives. The new edge of the conductive rubber layer is to be canted. The insulation surfaces treated must be smooth and clean. Seite: 7