JP2576100B2 - Leading method of CV cable with corrugated metal sheath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION The present invention is an improved method for making lead work in a corrugated metal sheathed CV cable, such as a crosslinked polyethylene insulated aluminum coated vinyl corrosion resistant cable (CAZV). Providing a method.

[Conventional technology and its problems]

In recent years, with the use of ultra-high pressure in this type of CV cable, it has been studied to connect a copper or brass connecting tube to the metal sheath on the cross-linked polyethylene insulated cable core at the connection part and the terminal part by plumbing. .

By the way, when performing lead work on such a CV cable, the temperature of the lead work part at the time of work will be 150 ° C or more, so the temperature inside the metal sheath may exceed 120 ° C, and the crosslinked polyethylene insulator may be heated. There was a risk of causing deterioration. For this reason, conventionally, when the temperature inside the metal sheath is likely to exceed 120 ° C., a method has been adopted in which the lead work is temporarily stopped, cooled sufficiently, and then the lead work is performed again. However, such a method takes a long time to lead tool industry by (in the case of the way 500kv 2000 mm ² aluminum the CV cable took approximately 8 hours.) Further, to sufficiently increase the mechanical strength of Namariko portion There was a problem that it was difficult to do.

[Means for solving the problem]

In view of the above-mentioned problems of the prior art, the present invention can reduce the thermal effect on the crosslinked polyethylene insulated cable core, perform lead work on the metal sheath surface thereon in a short time, and have high mechanical strength. The purpose of the present invention is to provide a method of lead processing of this kind of CV cable which is improved so that a lead processing part can be formed. The gist of the method is as shown in the attached drawings, wherein a plurality of heat insulating sheets ( 11) are inserted at equal intervals in the circumferential direction between the cable core (1) and the applied metal sheath (7) from the end of the corrugated metal sheath (7),
At this time, a gap (8a) communicating in the cable longitudinal direction between the heat insulating sheet (11) and the corrugated metal sheath (7).
And a gap (8b) communicating in the cable axis direction between adjacent side edges of the plurality of heat insulating sheets (11). The corrugated metal sheath (7) on the corrugated metal sheath (7) surface
And forming a lead portion (10) for connecting between the connection copper pipe (9) and the connection copper tube (9).

〔Example〕

Hereinafter, description will be made with reference to FIGS. 1 and 2 of the accompanying drawings. In the figure, reference numeral 1 denotes a cable core, a conductor 2 is coated with a cross-linked polyethylene insulator 4 via an internal semiconductive layer 3, and an external semiconductive layer 5 and a conductive buffer layer 6 are sequentially applied thereon. Things.

Reference numeral 7 denotes a metal sheath corrugated with a metal material such as aluminum, which is covered with a gap 8 on the conductive buffer layer 6 of the cable core 1.

Reference numeral 9 denotes a connecting body tube at a connecting portion or a terminal portion, which is lead-connected to the surface of the corrugated metal sheath 7. 10 indicates a lead section.

The present invention provides a heat insulating sheet 11 on the conductive buffer layer 6 serving as the surface layer of the cable core 1 inside the corrugated metal sheath 7 where the lead connection is performed in such a lead connection section. Are wound around the circumference at equal intervals, and a lead connection between the corrugated metal sheath 7 and the connection body tube 9 is performed on the portion where the heat insulating sheet 11 is present.

By interposing the heat insulating sheet 11 in this manner, high heat during lead work is cut off on the cable core, and the influence of heat on the cable core 1 inside the sheath is reduced.

The present invention further provides a gap 8 between the corrugated metal sheath 7 and the cable core 1 penetrating in the cable longitudinal direction between the interposed heat insulating sheet 11 and the corrugated metal sheath 7 thereon. A continuous gap 8a is held, and a gap 8b communicating with the adjacent side edges of the plurality of heat insulating sheets 11 is provided so as to be spaced apart from each other and communicates with each other in the axial direction. This is to make a lead connection.

By having such gaps 8a and 8b, air heated by the lead work can flow positively in the longitudinal direction of the cable between the corrugated metal sheath 7 and the cable core 7, so that heat is partially transmitted. Heat distribution in the longitudinal direction of the cable is facilitated without a cage.

In this way, since the thermal effect on the cable core 1 due to the lead work is significantly reduced, the lead work part 10 can be formed by one continuous lead work.

By the way, 500 kv 2000 mm ² CAZV was used as the cable, and a 1 mm thick, 40 mm wide fluororesin sheet between the corrugated aluminum sheath and the conductive buffer layer on the inner surface of the cable core was placed around the cable core. 4 at equal intervals
Inserted. At this time, the side edges of the adjacent sheets are spaced apart from each other, and a gap is formed therebetween so as to communicate in the axial direction. Further, a gap is provided between the sheet and the corrugated aluminum sheath, which is communicated in the axial direction by a spiral concave portion on the corrugated inner surface of the sheath.

In this state, one continuous lead work was performed at a temperature of 150 ° C. between the surface of the corrugated aluminum sheath on the heat insulating sheet and the copper body tube. The sheath temperature at a position 200 mm apart in the longitudinal direction was 140 ° C, but the maximum temperature of the crosslinked polyethylene insulator in the cable core immediately below the lead section was 110 ° C, and the allowable heat resistance temperature of the crosslinked polyethylene insulator was It has been confirmed that it can be performed at a lower temperature. In addition, it was confirmed that the plumbing operation time was about 30 minutes.

As described above, the lead work formed by one continuous lead work has excellent mechanical strength, and is more sufficient than that of the lead work formed by several intermittent lead work as in the past. It was also confirmed that it had improved.

The heat insulating sheet may be made of a material such as a mica sheet having excellent heat resistance and heat insulating property and excellent mechanical properties in addition to the fluororesin.

In addition, in the present invention, a space is provided between the heat insulating sheet and the corrugated metal sheath, and the space is communicated with the gap between the cable core and the corrugated metal sheath. Then, by forcibly moving the air between the cable core and the corrugated metal sheath with a fan or the like, it is possible to efficiently disperse the heat that is easily sunk even during lead work.

[Effect of the invention]

As described above, according to the method of the present invention, when the lead work is performed by the heat insulating sheet interposed on the inside of the cross-linked polyethylene insulated cable core where the lead connection of the corrugated metal sheath is performed. High heat is cut off, and the air heated at the time of the lead work between the cable core and the metal sheath does not convect to a certain place, and the gap between the heat insulating sheet and the corrugated metal sheet and a plurality of Since the heat can be quickly dispersed through the gap in the longitudinal direction of the cable through the gap between the adjacent side edges of the heat insulating sheet, the heat can be quickly dispersed.
The thermal effect of lead work on crosslinked polyethylene insulation in the cable core is significantly reduced, so that a lead connection with excellent mechanical strength can be formed in a short time in this type of CV cable with metal sheath. To play.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show an embodiment of a lead connection method for a CV cable with a corrugated metal sheath according to the present invention, and FIG. 1 is a partially cutaway side view. FIG. 2 is an explanatory sectional view taken along line XX of FIG. 1: cable core, 4: cross-linked polyethylene insulator, 7: corrugated metal sheath, 8: gap, 9: connecting body tube, 10: lead section, 11: heat insulating sheet, 8a: gap, 8b: gap.

Claims (1)

(57) [Claims] 1. A plurality of heat insulating sheets (11) are equally spaced circumferentially from the end of a corrugated metal sheath (7) between a cable core (1) and the corrugated metal sheath (7). At this time, the heat insulating sheet (11) and the corrugated metal sheath (7)
And a gap (8a) communicating in the cable axial direction between the adjacent side edges of the plurality of heat insulating sheets (11) while securing a gap (8a) communicating with the cable in the longitudinal direction of the cable. Thereafter, a lead portion (10) for connecting between the corrugated metal sheath (7) and the connecting copper tube (9) on the surface of the corrugated metal sheath (7) on the heat insulating sheet (11). A method for lead-forming a CV cable with a corrugated metal sheath, characterized by forming a wire.