JP3013368B2 - Solid submarine power cable - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solid submarine power cable that does not require refueling from both ends of the cable.

(Prior art and problems to be solved) Since a solid type power cable does not have an oil tank, a load is applied to the power cable, the temperature of the conductor and the insulating layer rises, and a high-viscosity solid insulation impregnated in the insulating layer is applied. When the oil expands and the load is removed and the conductor and the insulating layer are cooled, the solid insulating oil contracts. Such expansion and contraction of the insulating oil is repeated locally and locally because the viscosity of the insulating oil is high.

When such a solid type power cable is used for a submarine cable, for example, in a shallow sea area of about 150 m or less, the expansion of the insulating oil causes the lead sheath to balance with the pressing force of a reinforcing tape such as stainless steel or bronze provided on the outside thereof. Although it expands to the point, even if the insulating oil shrinks, the external pressure due to seawater is small, so the lead sheath does not shrink, even if external force is repeatedly applied to the inner insulating layer, it does not damage the insulating layer, Also, there is no damage to the lead coating.

However, when the water depth exceeds 150 m, the external pressure due to seawater increases, and the lead sheath expands and contracts following the expansion and contraction of the insulating oil due to load fluctuations, damaging the internal insulating layer and forming a circular lead sheath. For this reason, concentrated strain is caused by expansion and contraction, and damage is caused by repeated strain. In addition, in the case of remarkable, vertical shrinkage of lead occurs due to seawater pressure during contraction,
Thereafter, this does not go away and grows larger, leading to damage to the lead coating or damage to the inner insulating core.

In order to avoid the above-mentioned phenomena, in the case of a solid type submarine power cable for deep sea, measures have been taken to form an oblong conductor, wind an insulating layer thereon, and apply an oblong lead coating.
With this configuration, the ratio of the ellipse, that is, the ratio of the major axis / minor axis (for example, 1.
In a certain range according to 1), the lead coat also keeps the outer circumference constant and smoothly repeats the oval → circular → oval to absorb the amount of expansion and contraction of the insulating oil, without damaging the insulating layer,
Also, no concentrated strain occurs on the lead coating.

However, manufacturing an elliptical conductor and winding an insulating tape thereon to form an elliptical insulating layer requires very difficult techniques and equipment, and significantly reduces productivity. Electrically, the lines of electric force (a) are concentrated on the portion where the curvature of the elliptical conductor is the smallest, as shown in FIG. 2 (a), which is a weak point. Therefore, it is necessary to increase the thickness of the insulating layer so that necessary withstand voltage characteristics are obtained at this portion, which leads to an increase in the outer diameter of the cable. Even so, this is still an electrical weakness.

(Means for Solving the Problems) The present invention provides a solid-type submarine power cable that has solved the above-mentioned problems, and is characterized by winding an insulating tape impregnated with a high-viscosity insulating oil on a circular conductor. And a spacer is disposed at a position facing the outside of the cable core provided with the shielding layer on the insulating layer, and a lead sheath is provided on the outer periphery of the cable core and the spacer, and the lead sheath is formed by the spacer. It is held in an oval shape, and a plastic coating layer is provided outside the lead coating, and an iron wire sheath is provided outside the plastic coating layer.

(Operation) In the above-described solid submarine power cable of the present invention, a circular conductor is used, a circular insulating layer is provided on the circular conductor, and a shielding layer is provided on the insulating layer.
It can be manufactured by conventional power cable manufacturing equipment and manufacturing technology.

In addition, since the shielding layer electrically on the ground side is also circular, as shown in FIG. 2 (b), the lines of electric force (a) are uniform radially from the ideal center in the cable, and There are no significant weaknesses.

(Embodiment) FIG. 1 is a cross-sectional view of a specific example of the solid type submarine power cable of the present invention.

In the drawings, (1) is a circular conductor such as a compressed circular conductor used as a conductor of an ordinary power cable, and (2) is a composite insulating tape obtained by laminating and integrating a kraft insulating paper and a plastic film such as a polypropylene with a kraft insulating paper. , An ethylene-propylene copolymer film, or an insulating layer in which these are mixed and wound and then impregnated with a high-viscosity insulating oil; (3) a shielding obtained by winding carbon paper, metal tape, copper woven cloth tape, or the like; In order to obtain the ideal lines of electric force in the layer as described in the above operation, this shielding layer (3) needs to be electrically connected to the lead coating (6) applied thereon. is there.

(4) is a spacer arranged at an opposing position outside the shielding layer (3). This spacer (4) is provided with a shielding layer (3).
The lead coat (6) applied on the upper surface is arranged to be kept in an oval shape. The spacer (4) is preferably made of a material having substantially the same mechanical properties as the material constituting the insulating layer (2). In this sense, the spacer (4) is formed of the same material as the material used for the insulating layer.
It is preferable because there is no fear of lowering the insulation performance. However, since it is ultimately a spacer for holding the lead sheath in an oblong shape, for example, an extruded product of plastic, an extruded product having an insulating tape wound on the core, lead or a lead alloy May be used as a core and an insulating tape wound thereon. Such spacers (4) are arranged on opposite sides of the circular core, and metal tape, copper woven cloth tape,
Alternatively, a conductive tape (5) obtained by winding these tapes together with a semiconductive cloth tape as a cushion layer, carbon paper, a semiconductive plastic tape, an insulating paper tape, or the like.
And lead coating (6) is applied thereon. The spacer (4) may be made of a conductive material.

In this way, if the conductive tape (5) is wound around the outer periphery of the spacer (4), the shielding layer (3) on the circular insulating layer (2) and the spacer (4) are electrically connected, and furthermore, The spacer (4) and the lead sheath (6) are preferably electrically connected in the same manner.

Further, the outer surface of the elliptical lead sheath (6) is made easier to handle the iron wire sheathing (8), and the handling of the cable after the sheathing is made easier. In order to prevent damage due to concentration of external force due to a certain reason, a plastic coating layer (7) such as polyethylene having a circular outer shape is provided, and an iron wire sheath (8) is provided on the outside thereof.

In order to provide the plastic covering layer (7) having such a circular outer shape, the outer spacer (9) is disposed at a position substantially perpendicular to the spacer (4) in the lead sheath (6), and polyethylene or the like is placed thereon. Plastic may be extruded,
Alternatively, the plastic coating layer (7) may be formed without using the outer spacer (9) by extruding the plastic material into a circular shape after extruding outside the oval lead cover (6) so that the plastic material becomes circular.

(Effects of the Invention) As described above, according to the solid type submarine power cable of the present invention, the cable core uses the circular conductor and the circular insulating layer as in the case of the ordinary power cable, so that the ordinary production technology and production equipment can be used. Manufacturing becomes possible, and productivity is remarkably improved.

In addition, since there is no electrical weak point of the insulating layer as compared with the elliptical conductor and the elliptical insulating layer, the insulation thickness can be reduced accordingly, and the outer diameter of the cable can be reduced accordingly.

Further, by providing a plastic coating layer having a circular outer shape on the outside of the oval lead sheath and applying an iron wire sheathing on the outside thereof, the exterior work is facilitated, and the cable having the oval shape during and after laying is formed. There is no possibility of injury due to concentration of external force.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a specific example of the solid submarine power cable of the present invention. FIG. 2 is an explanatory view of electric lines of force generated in the insulating layer. FIG. 2A shows the case of the conventional cable, and FIG. 2B shows the case of the cable of the present invention. 1 ... circular conductor, 2 ... circular insulating layer, 3 ... shielding layer, 4
... spacer, 5 ... conductive tape layer, 6 ... lead coating, 7
... plastic coating layer, 8 ... iron wire sheath, 9 ... outer spacer.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 7/14 H01B 9/00

Claims (3)

(57) [Claims] An insulating layer formed by winding an insulating tape impregnated with high-viscosity insulating oil is provided on a circular conductor, and a spacer is provided at a position facing the outside of a cable core having a shielding layer provided on the insulating layer. A lead sheath is provided on the outer periphery of the cable core and the spacer, and the lead sheath is held in an oval shape by the spacer,
A solid type submarine power cable, further comprising a plastic coating layer provided outside the lead coating, and an iron wire exterior provided outside the plastic coating layer. 2. The solid type submarine power cable according to claim 1, wherein a conductive tape is wound around an outer periphery of the spacer, and / or the spacer is made conductive. 3. The solid submarine power cable according to claim 1, wherein the outer shape of the plastic coating layer applied to the outside of the oval lead sheath is circular.