JPS59174291A - Welding method of lead sheath for submarine cable - Google Patents

Abstract

PURPOSE:To eliminate thoroughly the thermal influence on an insulator in the stage of welding the lead sheath of a submarine cable by winding a metallic tape having a good heat conductivity in the weld zone on a cable core, winding metallic pipes on both sides in the weld zone of the lead sheath and lead pipe, and running refrigerant therein. CONSTITUTION:A metallic tape 7 of copper, etc. having good heat conductivity is wound on the weld zone 3 on a cable core 8, in welding the lead sheath of a submarine cable 1 using semisynthetic insulating paper. Lead pipes 4 are wound on both sides in the weld zone 3 of a lead sheath 1 and a lead pipe 2 and while a refrigerant such as an insulating oil 6 is circulated therein by means of a pump 5, the sheath 1 and the pipe 2 are welded to each other. The welding heat is then deprived of by the refrigerant and at the same time the tape 7 is contributed to heat radiation, by which the concn. of heat is eliminated and the thermal influence on the insulator is throroughly eliminated.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a method for reducing lead coating when semi-synthetic paper insulating paper with a relatively low softening point, such as PPLP, is used in large-capacity submarine OF cables for the purpose of increasing power transmission capacity. Regarding welding methods.

[Conventional technology and problems]

Conventionally, when using a semi-synthetic insulating paper with a relatively low softening point such as PL There was a problem that the insulator could soften and melt because it easily spreads to other parts.

[Structure of the invention]

The present invention was made to solve one of the problems mentioned above, and its characteristics are that after wrapping a metal tape with good thermal conductivity around the welded part on the cable core, it is possible to connect the lead covering to the lead. The process involves wrapping metal pipes around both sides of the tusk and welding the lead sheath by flowing a refrigerant through the pipes.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

In Figure 1, 1 is a cable lead sheath, and 2 is a lead pipe.

6 is a welding part. Since water cannot be allowed inside the welding area during lead welding, it is not possible to use methods such as pouring water onto the welding area 6. Therefore, as shown in Figure 1, space should be provided on both sides of the welding area so that it will not interfere with welding. A lead pipe 4 is wound as shown in the figure, and the cable lead sheath 1 and the lead pipe 2 are welded together while insulating oil 6 is circulated around the pump 5. It is also possible to use a pressure oil tank instead of the pump 5 to flow the oil.

Water may be used as the cooling medium, but if the pipe is defective and leaks, it may leak into the cable, so water is preferably the same as the cable insulating oil.

During welding, the heat concentrated area becomes very high temperature, so it was found that the thermal effect on the insulating paper cannot be avoided using only the cooling method described in 2. Therefore, as shown in Figure 2, a copper tape 7 with good heat conductivity was applied to the welded area A. The cable core 8(1) is wound around the outer periphery of the cable core (outer diameter), and welding is performed by adding the method shown in FIG.

〔Effect of the invention〕

In the conventional method without cooling, it was unavoidable that several outer layers of semi-synthetic paper would melt, but when the welding heat is removed by oil as in the present invention, it is possible to eliminate heat concentration as much as possible. A significant effect is that the copper tape on the core contributes to heat dissipation and completely eliminates any thermal effects on the insulator.

[Brief explanation of the drawing]

All drawings relate to the lead welding method of the present invention.
Fig. 2 is an explanatory diagram showing a metal pipe wrapped around both sides of a welded part to flow a refrigerant, and Fig. 2 is an explanatory diagram of a copper tape wrapped around the cable core of the welded part. 1... Lead covering, 2. Lead pipe, 6... Welded part, 4... Metal pipe, 5... Pump, 6... Insulating oil, 7... Copper tape, 8... Cable core, D. Cable. Core outer diameter.

Claims (1)

[Claims] 1. To weld the lead sheath of a cable, a metal tape with good thermal conductivity is wrapped around the welded part on the cable core, and then metal pipes are wrapped on both sides of the welded part of the lead sheath and the lead pipe. A method for welding lead-covered submarine cables, the method comprising welding by flowing a refrigerant through the pipe. 2. The lead welding method for submarine cables as set forth in claim 1, wherein the refrigerant flowing through the metal pipe is insulating oil.