JP2002118921A - Method for pulling in power cable into pof cable pipe, and structure of power cable for pof cable pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of power cable to be pulled into a POF cable pipe, which enables replacement of an exsisting resin-insulated power cable without having to take into can sideration measures for water and oil and can reduce the outside diameter through significant rationalizing cable structure, when pulling a resin-insulated cable into a newly provied or existing metal pipe for POF cable or replacement thereof. SOLUTION: The method for pulling in the resin-insulated power cable into the POF cable pipe or the replacement of the exsistign cable comprises the steps of removing the POF cable and insulation oil from the metal pipe for a newly provided POF cable or the existing POF cable, cleaning the inside of the POF cable pipe after removing the insulation oil and POF cable, vacumizing the inside of the same pipe, pulling a resin-insulated power cable into the pipe 14 and sealing the pipe to which the power cable is pulled in with an inert gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable for a POF cable pipe using cross-linked polyethylene insulation or the like which is effective for replacing a POF cable in an existing metal pipe for a POF cable (pipe type POF cable). The present invention relates to a drawing method and a structure of a power cable drawn into a POF cable pipe.

[0002]

2. Description of the Related Art A POF cable is a cable in which a plurality of cables are drawn into a steel pipe installed in an electric power transmission route, and the steel pipe is filled with insulating oil.

[0003] By the way, POF cables have been widely used as underground transmission lines of large capacity than before. However, since high-pressure insulating oil is used, it is necessary to provide a hydraulic compensating circuit and the like for a hydraulic circulation system. It is necessary to consider that maintenance costs are high because of long-term use, that the insulation may deteriorate if oil leaks for any reason, that the environment may be damaged, and that disaster prevention must be considered. There are various problems such as the necessity.

On the other hand, a cross-linked polyethylene cable (C) is used by using a pipe on which a POF cable is laid.
By replacing it with a V cable or an extruded resin insulated cable), the hydraulic compensator can be omitted, and the above problem can be solved.

The structure of a conventional CV cable is such that an inner semiconductive layer 2, an insulating layer 3, an outer semiconductive layer 4, and a shielding tape 5 are sequentially arranged on the outer periphery of a central conductor 1 as shown in a cross section in FIG. ,
The holding tape 6, the aluminum cover 7, and the anticorrosion layer 8 are sequentially arranged.

[0006]

However, the conventional CV cable has a disadvantage that the friction between the pipe and the cable is large and the length of the cable cannot be increased. In addition, conventional CV cables have a larger outer diameter than POF cables and have the same capacity and increase capacity because the insulator is weak to water and oil, and measures must be taken to prevent water and oil from entering. Difficult and too heavy.

[0007] Japanese Patent Application Laid-Open No. 11-27 already proposed by the applicant.
According to the technique described in Japanese Patent Publication No. 3465, POF
The cable is replaced with an insulated power cable and water is injected or circulated in the pipe. However, even in this technique, since water is always present around the cable, it is required to be strictly required in terms of waterproofness, so that it is necessary to construct a water-impervious layer well, and it is easy to increase the diameter and increase the weight. Furthermore, facilities for water injection and circulation are required, and there is a need for a technology that is more simplified by eliminating conditions such as water injection.

[0008] The present invention has been proposed in view of the above circumstances, and when replacing a resin insulated cable in an existing metal pipe for a POF cable, the resin insulated power cable can be used without taking measures against water and oil into consideration. POF cable pipes that can be exchanged, reduce the cable outer diameter by greatly streamlining the cable structure, reduce underground transmission line construction and maintenance costs, and improve disaster prevention. Method and P to draw power cable into
An object of the present invention is to provide a power cable structure to be drawn into an OF cable pipe.

[0009]

The present invention has the following features in order to achieve the above-mentioned object. The present invention relates to a new metal pipe for POF cable or an existing POF cable.
Removing the POF cable and insulating oil from the OF cable line, drawing in a resin-insulated power cable having friction reducing means on its surface in the pipe, and inactive in the pipe in which the power cable is drawn. Enclosing a gas (for example, nitrogen N ₂ gas) with a resin-insulated power cable into a POF cable pipe.

The present invention also relates to a resin insulated power cable drawn into a metal pipe for a new POF cable or a pipe for a POF cable in which insulating oil has been removed from an existing POF cable line.
An inert gas is sealed in a POF cable pipe from which a cable and insulating oil have been removed, and a resin insulated power cable having a friction reducing means provided on a surface thereof is drawn into the pipe. It is a power cable structure to be drawn in.

According to the method of drawing a power cable into a POF cable pipe and the power cable structure of drawing a POF cable into a POF cable pipe according to the present invention, an inert gas is sealed in the POF cable pipe from which the POF cable and the insulating oil have been removed. In addition, since the resin-insulated power cable having the friction reducing means provided on the surface thereof is drawn into the pipe, the inert gas can prevent oil and water from entering from outside the pipe, so that the insulating power The cable itself does not impair the characteristics of the cable, and does not require measures against oil and water (for example, a water blocking layer), thereby enabling a significant rationalization of the cable structure. Therefore, since a water barrier layer or the like is not required, the outer diameter can be reduced accordingly, and handling is easy, for example, a resin insulated power cable such as a CV cable can be easily drawn into the POF pipe. Further, since the oil circulation system is not required, maintenance for the oil can be omitted.

In the method for drawing an insulated power cable of the present invention, the POF cable pipe includes a step of cleaning the inside of the POF cable pipe after removing the insulating oil and the POF cable, and a step of vacuuming the inside of the pipe. By including it, the oil and water can be reliably removed before the resin insulated cable is drawn in, and the inert gas can be sealed with moisture and air removed. Oxidation can be prevented, so that the service life of the cable can be prolonged and maintenance work can be reduced.

It is preferable that the resin insulated cable is cooled in the POF cable pipe through a cooling liquid conduit. In this case, the power transmission capacity can be improved by suppressing the temperature rise of the cable.

Further, a metal film layer is provided on the outer peripheral surface of the semiconductive layer,
It is preferable that a metal skid wire is provided on the outer peripheral surface of the metal film layer as friction reducing means. With this configuration, the semiconductive layer is electrically connected to the pipe via the metal film layer and the friction reducing means, so that the electrical performance is improved and the ground fault can be protected. Note that, instead of the skid wire, a conductive or semiconductive resin can be provided by extrusion or the like.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows P according to the embodiment.
It is a cross-sectional explanatory view of the electric power cable structure drawn in to the OF cable pipe. The same parts as those in FIG. 2 are denoted by the same reference numerals.

The power cable of the embodiment is a newly installed POF.
POF cable such as a metal pipe or an underground line, and a resin-insulated power cable that is replaced with a POF cable metal pipe (for example, a steel pipe) after removing insulating oil, and the outer periphery of the center conductor 1 An inner semiconductive layer 2, an insulating layer 3, and an outer semiconductive layer 4 are sequentially arranged. The insulating layer 3 is, for example, a resin insulated power cable such as a CV cable extruded from cross-linked polyethylene. .

Further, in the step of pulling in or replacing in the embodiment, the step of removing the POF cable and the insulating oil from the newly installed metal pipe for the POF cable or the existing POF cable, and the step of removing the insulating oil and the POF cable Cleaning the inside of the POF cable pipe, vacuuming the inside of the pipe,
Drawing in a resin-insulated power cable provided with friction reducing means 12 on the surface thereof, and introducing an inert gas (for example, nitrogen N ₂₎ into the pipe into which the power cable has been drawn.
Gas) and a process of drawing a resin-insulated power cable into a POF cable pipe. Note that the method may include a step of putting an inert gas into the pipe before drawing in the cable. In addition, it is preferable that the inert gas is sealed by applying a pressure capable of preventing water from entering the pipe after the cable is introduced.

Here, the resin insulated power cable is provided with a metal tape 10 on the outer semiconductive layer 4 on the outer periphery of the insulating layer 3 and friction reducing means for reducing the frictional resistance between the outer peripheral surface of the resin insulated power cable and the inner surface of the pipe. 12 are provided. The metal tape 10 and the friction reducing means 12 are made of POF.
It is preferable to have conductivity with the metal pipe 14 for cables.

The metal tape 1 on the outer semiconductive layer
0 may or may not be provided. A metal tape (lead coating, aluminum coating, or stainless steel coating) or a metal film (stainless steel, copper, lead, aluminum, or the like) may be used as it is or may be laminated. In order to prevent the metal tape 10 from being unwound, a combination winding of the holding tape 16 may be considered. Various materials such as cloth, paper, resin, and metal (lamination is also possible) can be used for the holding tape 16.

As shown in FIG. 1, the friction reducing means 12 has a circular cross section, a semicircular cross section, an elliptical cross section,
A plurality of metal wires made of aluminum, copper, steel or stainless steel having a sectional shape or the like are spirally wound around the impermeable layer. By providing a plurality of skid wires, it is possible to ensure that stress is applied by the skid wires in the POF pipe, for example, at a pipe connection, an entrance or an exit.

Examples of the metal tape 10 and the skid wire of the friction reducing means 12 will be described below. Example 1 Skid wire: Material SUS, D-shaped cross section of 2.5 mm in height and 5 mm in width Metal tape: Material SUS, 2 in thickness of 0.2 mm
Example 2 Skid wire: Material SUS, D-shaped sectional shape of 2.5 mm in height and 5 mm in width Metal tape: None Example 3 Skid wire: Material SUS, Circular sectional shape of 2.5 mm in diameter Metal tape: Material SUS, 0.2 mm thick 2
Example 4 Skid wire: Material Copper, 20 pieces having a circular cross section of 2.4 mm in diameter Metal tape: None Example 5 Skid wire: Material SUS D-shaped cross section of 2.5 mm in diameter Metal tape: Material Copper Thickness 2 pieces of 0.1mm

According to the above embodiments and examples, the PO
According to the method of drawing the power cable into the F cable pipe and the structure of the power cable drawing into the POF cable pipe, the POF cable and the P from which the insulating oil is removed are removed.
After cleaning the inside of the OF cable pipe 14 and drawing it by vacuum, the resin insulated power cable provided with the friction reducing means 12 on its surface is drawn into the pipe and sealed with an inert gas. Water intrusion from the outside of the pipe can be prevented, so that the insulated power cable itself does not impair the characteristics of the cable, and no oil / water measures (for example, a water-blocking layer) are required, and a great rationalization of the cable structure is achieved. It is possible. Therefore, since a water barrier layer or the like is not required, the outer diameter can be reduced accordingly, and handling is easy, for example, a resin insulated power cable such as a CV cable can be easily drawn into the POF pipe. Further, since the oil circulation system is not required, maintenance for the oil can be omitted.

In the method of drawing an insulated power cable, the POF cable pipe is made of insulating oil and PO.
By including a step of cleaning the inside of the POF cable pipe after removing the F cable and a step of evacuating the inside of the pipe, the oil content and
Since water can be removed and inert gas can be sealed with moisture and air removed, not only the effects of oil and water, but also the oxidation of air due to oxygen can be prevented.
The service life of the cable can be extended, and the maintenance work can be reduced.

It is preferable that the resin insulated cable be cooled in the POF cable pipe together with the resin insulated power cable through a cooling liquid conduit. In this case, the power transmission capacity can be improved by suppressing the temperature rise of the cable.

Further, a metal film layer is provided on the outer peripheral surface of the semiconductive layer,
Since a metal skid wire is provided as a friction reducing means on the outer peripheral surface of the metal film layer, the semiconductive layer is electrically connected to the pipe via the metal film layer and the friction reducing means, so that the electric performance is improved, Can protect against entanglement. Note that, instead of the skid wire, a conductive or semiconductive resin can be provided by extrusion or the like.

In the present invention, the water blocking layer 10 and the friction reducing means 12 maintain the electrical connection between the POF cable pipe and the resin insulated cable only when the resistance value is 1 × 10 ⁷ Ωcm. It is preferably 1 × 10 ⁵ Ωcm or less.

In the power cable replaced with the metal pipe for a POF cable according to the present invention, a plurality of cables without the friction reducing means are provided collectively by winding a friction reducing means such as a skid wire at a predetermined pitch. May be.

[0028]

According to the present invention, since the POF cable and the POF cable pipe from which the insulating oil has been removed are filled with an inert gas and the surface of the pipe is provided with a friction reducing means, Since the provided resin insulated power cable was drawn in, the inactive gas can prevent oil and water from entering from outside the pipe, so that the insulated power cable itself does not impair the characteristics of the cable, Water measures (for example, impermeable layer) become unnecessary, and the cable structure can be greatly rationalized. Therefore, the need for a water-impervious layer or the like is eliminated, so that the outer diameter can be reduced accordingly.
Handling is easy, for example, a resin insulated power cable such as a CV cable can be easily drawn into the pipe. Further, since the oil circulation system is not required, maintenance for the oil can be omitted.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of a power cable structure drawn into a POF cable pipe according to an embodiment.

FIG. 2 is an explanatory view of a sectional view of a conventional CV cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor 2 Inner semiconductive layer 3 Insulating layer 4 Outer semiconductive layer 10 Metal tape 12 Friction reduction means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Ikuo Shigeno 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Jun Suzuki 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Fuminori Tateno 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Akihiro Onishi 1-1-1, Kiba, Koto-ku, Tokyo Fujikura Co., Ltd. (72) Inventor Takenori Nakajima 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Hajime Takena 1-5-1, Kiba, Koto-ku, Tokyo F-Terminal Co., Ltd. Reference) 5G313 AA01 AB03 AB10 AC03 AD01 AD07 AE08 5G369 AA01 AA05 AA06 BA04 DC04 DC20 EA01

Claims (5)

[Claims] 1. A step of removing a POF cable and insulating oil from a new POF cable metal pipe or an existing POF cable line, and a step of drawing a resin insulated power cable having a friction reducing means provided on a surface thereof in the pipe. Enclosing an inert gas in the pipe into which the power cable has been drawn.
A method of drawing resin-insulated power cables into cable pipes. 2. P after removal of insulating oil and POF cable
The method for drawing a resin-insulated power cable into a POF cable pipe according to claim 1, comprising: a step of cleaning the inside of the OF cable pipe; and a step of evacuating the inside of the pipe. 3. A resin-insulated power cable drawn into a new POF cable metal pipe or a POF cable pipe obtained by removing a POF cable and an insulating oil from an existing POF cable line, wherein the POF cable and the insulating oil are removed. An electric power cable structure for drawing into a POF cable pipe, wherein an inert gas is sealed inside the POF cable pipe, and a resin insulated power cable having a friction reducing means provided on a surface thereof is drawn into the pipe. 4. The power cable structure according to claim 2, wherein the inside of the POF cable pipe is cooled through a coolant passage. 5. The semiconductor device according to claim 2, wherein a metal film layer is provided on an outer peripheral surface of the semiconductive layer, and a metal skid wire is provided on the outer peripheral surface of the metal film layer as friction reducing means. Power cable structure to be drawn into the POF cable pipe.