JP2017175682A - Cable laying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable laying method capable of reducing a stress that acts on a cable during laying, without using a tension member.SOLUTION: The present invention relates to a cable laying method for laying a cable inside of a conduit line. The cable laying method includes: interposing a sheet material between the cable and the conduit line; and hauling the sheet material, thereby pulling the cable that is mounted on the sheet material, into the conduit line. According to the cable laying method, a stress that acts on the cable during laying can be reduced without using a tension member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cable laying method for laying a cable in a pipeline.

  Conventionally, a cable or the like is laid in a pipe line (for example, a fume pipe). A typical example of the cable is a power cable such as an OF cable or a CV cable. In recent years, it has been studied to install a superconducting cable in a pipeline instead of a normal conducting power cable arranged in the pipeline.

  When laying a cable in a pipeline, the cable is pulled from one end side to the other end side of the pipeline. At that time, since a large stress acts on the cable, it is necessary to prevent the cable from being damaged by the stress. For example, Patent Document 1 discloses a configuration in which a tension member is provided outside a heat insulating tube provided in a superconducting cable so that the installation tension is shared by the tension member and the stress acting on the cable excluding the tension member is reduced. .

JP 2006-59695 A

  In the configuration using the tension member described in Patent Document 1, since the weight of the cable increases by the amount of the tension member, handling of the cable becomes complicated, and the laying tension of the cable increases by the amount of the increase in weight. Further, since the outer diameter of the cable is increased by the amount of the tension member, there is a limit to the pipe line through which the cable including the tension member can be laid. In particular, when a cable is laid in an existing pipe line, there is a restriction on the outer diameter of the cable that can be laid according to the laying space in the pipe line. There are cases where it cannot be laid inside.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a cable laying method that can reduce stress acting on a cable during laying without using a tension member. .

  A cable laying method according to an aspect of the present invention is a cable laying method for laying a cable in a pipeline, and a sheet material is interposed between the cable and the pipeline, and the sheet material is pulled. In the cable laying method, the cable placed on the sheet material is drawn into the pipeline.

  According to the cable laying method, the stress acting on the cable at the time of laying can be reduced without using a tension member.

It is a schematic explanatory drawing of the cable laying method which concerns on embodiment. It is a schematic cross-sectional view of a low-temperature insulated superconducting cable.

-Description of embodiment of this invention First, the embodiment of this invention is listed and demonstrated.

<1> The cable laying method according to the embodiment is a cable laying method for laying a cable in a pipeline, and a sheet material is interposed between the cable and the pipeline to pull the sheet material. In the cable laying method, the cable placed on the sheet material is drawn into the pipeline.

  Normally, on the cable delivery side, the rotation speed of the drum around which the cable is wound is adjusted in accordance with the speed at which the cable is drawn into the pipeline, so that no more stress than necessary is applied to the cable delivery end. . Furthermore, in the cable laying method, since the cable pulling end is not pulled directly by pulling the sheet material while the cable is placed on the sheet material, almost no stress acts on the cable pulling end. . As a result, the stress acting on the entire cable, i.e., the tensile stress generated when laying, is significantly smaller than when pulling the cable pull-in end, and the cable is excessively stretched due to excessive stress acting on the cable. Can be suppressed. That is, according to the cable laying method, a cable that does not include a tension member can be used as a cable drawn into the pipe. If it is not necessary to provide a tension member in the superconducting cable, the dimensional restriction of the superconducting cable that can be laid in the pipe line can be relaxed.

  Moreover, in the said cable laying method, since a sheet | seat material is interposed between a cable and a pipe line, it can suppress that the outer periphery of a cable is rubbed and damaged by a pipe line at the time of laying.

<2> As one form of the cable laying method according to the embodiment, a form in which the elongation of the sheet material at the time of laying is not more than the allowable elongation of the cable can be mentioned.

  If the elongation of the sheet material at the time of laying is not more than the allowable elongation of the cable, the elongation of the cable placed on the sheet material is also not more than the allowable elongation. In this case, it is preferable that the cable does not slip on the sheet material, and the sheet material and the cable move together when the sheet material is pulled. In that case, the sheet material plays the same role as the tension member.

<3> As one form of the cable laying method according to the embodiment, the elongation of the sheet material at the time of laying is equal to or greater than the allowable elongation of the cable, and the sheet material is pulled while sliding the cable on the sheet material. Along with this, a form in which the cable is drawn into the pipe line can be mentioned.

  If the sheet material is stretched more than the cable's allowable elongation during installation, that is, if the sheet material is made of an easily stretchable material, the cable may be stretched beyond the allowable elongation if the sheet material and the cable move together. There is. On the other hand, it can suppress that a cable is extended more than allowable elongation by sliding a cable on a sheet | seat material like the said structure. In order to slide the cable on the sheet material, for example, the friction coefficient of the surface on the cable side of the sheet material is set to a predetermined value or less.

<4> As one mode of the cable laying method according to the embodiment in which the cable is slid on the sheet material, a mode in which the coefficient of friction of the surface on the cable side in the sheet material is 0.3 or less is mentioned. it can.

  By using a slippery sheet material having a friction coefficient of 0.3 or less on the cable side surface of the sheet material, it is possible to prevent the cable from being stretched beyond the allowable elongation along with the elongation of the sheet material.

<5> As one form of the cable laying method according to the embodiment, a form in which the coefficient of friction of the surface on the pipe line side in the sheet material is 0.3 or less can be mentioned.

  By using a slippery sheet material having a friction coefficient of 0.3 or less on the surface of the sheet material on the duct side, it is possible to reduce the force of pulling the sheet material during laying, and as a result, the elongation of the sheet material is reduced. it can. The friction coefficient is more preferably 0.2 or less, and further preferably 0.1 or less. In addition to setting the friction coefficient of the sheet side surface of the sheet material to a predetermined value or less, and sliding the cable on the sheet material with the friction coefficient of the cable side surface of the sheet material being set to a predetermined value or less, The stress acting on the cable that has been ridden can be further reduced.

<6> As one form of the cable laying method according to the embodiment, on the supply side of the cable, a form in which the outer periphery of the cable is sandwiched and the cable is pushed into the pipe line can be exemplified.

  By applying a pushing force against the frictional force to the cable on the cable supply side, the stress acting on the cable can be reduced.

<7> As one form of the cable laying method according to the embodiment, the cable includes a cable core having a superconducting conductor and an insulating layer disposed on an outer periphery thereof, and a heat insulating tube that houses the cable core therein. The form which is a low-temperature insulation type superconducting cable can be mentioned.

  In the low-temperature insulated superconducting cable, the inner tube and the outer tube of the heat insulating tube are not in close contact. The frictional force between the pipe and the cable generated when the cable is pulled is applied to the outer pipe of the heat insulating pipe, and a large stress acts on the outer pipe, causing expansion and contraction and deformation of the outer pipe. For this reason, the outer tube of the heat insulating tube may be damaged, or the heat insulating performance may be deteriorated due to the relative behavior of the inner tube and the outer tube. Therefore, conventionally, a tension member is provided outside the heat insulating tube. On the other hand, if the cable laying method according to the embodiment for pulling the low-temperature insulated superconducting cable through the sheet material, the stress acting on the outer tube of the heat insulating tube is reduced without providing a tension member. There is no need to place a tension member on the heat insulation pipe.

-Details of the embodiment of the present invention Details of the embodiment of the present invention will be described below. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included.

<Embodiment 1>
≪Cable laying method≫
In the present embodiment, a cable laying method for laying the cable 1 in the pipe line 8 will be described based on FIG. Here, the pipe line 8 may be an existing pipe line or a new pipe line. Examples of the pipe line include a fume pipe buried in the ground.

  In laying the cable 1 in the pipe line 8, the cable 1 and the sheet material 2 are prepared. Examples of the cable 1 include normal conducting power cables such as OF cables and CV cables, and superconducting cables using a superconducting conductor. In this example, an example in which a superconducting cable including a heat insulating tube is pulled will be described. The specific configuration of the superconducting cable will be described after the laying procedure is finished. On the other hand, a sheet material 2 having a length equal to or longer than the entire length of the cable 1 is prepared. The sheet material 2 is wound up in a roll shape. The detailed configuration of the sheet material 2 will also be described after the laying procedure is finished.

  When the cable 1 and the sheet material 2 are prepared, the sheet material 2 is interposed between the cable 1 and the pipe line 8, and the cable 1 placed on the sheet material 2 is pulled inside the pipe line 8 by pulling the sheet material 2. Pull in. Specifically, first, the pulling member 5 is attached to the leading end of the sheet material 2 so that the leading end of the sheet material 2 has a bag shape at one end side (left side of the sheet) of the conduit 8, and the cable is placed on the sheet material 2. Put one. The pulling member 5 preferably has a curved end so as not to be caught by a bent portion of the pipe line 8, and a guide (member leading the pulling member 5) is further mounted in front of the pulling member 5. Is also preferable. Then, by winding the pulling wire 4 connected to the pulling member 5 with the winding device 3 arranged on the other end side of the pipe line 8, the cable 1 is inserted into the pipe line 8 from one end side of the pipe line 8. Can be pulled in and laid. Since the sheet material 2 is thin and not bulky, it can be placed in the conduit 8 together with the cable 1.

  Usually, on the supply side of the cable 1, the rotational speed of a drum (not shown) around which the cable 1 is wound is adjusted in accordance with the speed at which the cable 1 is drawn into the pipe line 8, and more than necessary at the delivery end of the cable 1. The stress is not applied. Further, on the supply side of the cable 1, a pressing force that opposes the frictional force with the sheet material 2 acting on the cable 1 may be applied to the cable 1. In order to apply the pushing force to the cable 1, for example, the cable 1 may be pushed into the pipe line 8 by sandwiching the cable 1 with a rotary driving body such as a ball roller or an endless track.

  In the cable laying method described above, since the pulling end of the cable 1 is not pulled directly by pulling the sheet material 2 while the cable 1 is placed on the sheet material 2, stress is applied to the pulling end of the cable 1. Almost no effect. As a result, the stress acting on the entire cable 1 is significantly smaller than when the pulling end of the cable 1 is pulled, and it is possible to suppress the cable 1 from being excessively stretched due to excessive stress acting on the cable 1. In this cable laying method, the cable 1 can be laid in the pipe line 8 without causing the cable 1 to be damaged without providing the cable 1 with a tension member.

  Moreover, in the said cable laying method, since the sheet | seat material 2 is interposed between the cable 1 and the pipe line 8, it can suppress that the outer periphery of the cable 1 is rubbed and damaged by the pipe line 8 at the time of laying.

≪Cable≫
Next, the configuration of the cable 1 laid by the cable laying method will be described. As already described, the cable 1 laid in the pipe line 8 is not particularly limited, but here, the low-temperature insulated superconducting cable 100 shown in FIG. 2 will be described.

[Low-temperature insulated superconducting cable]
A low-temperature insulated superconducting cable 100 shown in the cross-sectional view of FIG. 2 includes a cable core 10 having a superconducting conductor and a heat insulating tube 20 that houses the cable core 10 therein.

{Cable core}
The cable core 10 has a configuration in which a superconducting conductor layer 12, an insulating layer 13, an outer conductor layer 14, and a protective layer 15 are sequentially provided on the former 11. The former 11 is a member used as a support for the superconducting conductor layer 12. For example, a pipe-shaped hollow body as shown in FIG. 2 can be used as the former 11. The hollow former 11 can use the inside as a flow path of the refrigerant 131. As the shape of the former 11, a solid body such as a stranded wire can be used in addition to a hollow body. On the other hand, the material of the former 11 is not particularly limited. If the former 11 is simply used as a support for the superconducting conductor layer 12, the former 11 may be made of a non-conductive material such as a resin, and the former 11 also has a function as a current dividing path for abnormal current. If it can be used, it may be made of a normal conducting metal material such as copper or aluminum.

  Next, as the superconducting conductor layer 12, for example, a tape-like wire material including an oxide superconductor can be suitably used. Examples of the tape-shaped wire include Bi2223 superconducting tape wire (sheath wire in which a filament made of an oxide superconductor is arranged in a stabilizing metal such as Ag-Mn and Ag), RE123 thin film wire (RE: rare earth element, For example, Y, Ho, Nd, Sm, Gd, etc. (Laminated wire material in which an oxide superconducting phase is formed on a metal substrate). The superconducting conductor layer 12 includes a single layer structure or a multilayer structure formed by spirally winding the tape-shaped wire.

  The insulating layer 13 protects the superconducting conductor layer 12 and insulates between a heat insulating tube 20 and a superconducting conductor layer 12 described later, and can be formed by winding kraft paper or the like.

  When the outer conductor layer 14 is composed of a superconducting conductor, the AC cable functions as an electromagnetic shield, and the DC cable functions as a return current conductor. Further, the protective layer 15 has a predetermined insulating characteristic and mechanically protects the outer superconducting conductor layer (or outer shielding layer) 14.

{Insulated pipe}
The heat insulating tube 20 includes an inner tube 21 that houses the cable core 10 therein, and an outer tube 22 that houses the inner tube 21 inside. It is preferable to form an anticorrosion layer (not shown) having a predetermined insulating property and protecting the outer tube 22 from impact and corrosion on the outer periphery of the outer tube 22.

  The inner tube 21 is filled with a refrigerant 131 (typically liquid nitrogen, liquid helium, helium gas, etc.) for maintaining the superconducting conductor layer 12 in a superconducting state, and functions as a refrigerant flow path. By forming the heat insulating tube 20 with the inner tube 21 and the outer tube 22 provided on the outer periphery of the inner tube 21, it is possible to suppress the temperature of the refrigerant 131 from rising due to intrusion heat from the outside. A vacuum is drawn between the inner tube 21 and the outer tube 22 to form a vacuum heat insulating layer. In addition, if a heat insulating material such as super insulation (trade name) or a spacer that separates the inner tube 21 and the outer tube 22 is disposed between the inner tube 21 and the outer tube 22, the heat insulating property of the heat insulating tube 20 can be improved. . In addition, in this embodiment, although the heat insulation pipe | tube of a double pipe structure is utilized as a heat insulation pipe | tube, you may utilize the heat insulation pipe | tube more than a triple pipe.

  Examples of the constituent material of the inner tube 21 and the outer tube 22 include metals such as stainless steel, aluminum, and alloys thereof. Since the metal is excellent in corrosion resistance, it is suitable as a constituent material of the heat insulating tube 20 that holds and transports various fluids. The materials of both pipes 21 and 22 may be different. Moreover, both the pipes 21 and 22 are easy to bend | curve by making it the corrugated pipe to which the corrugation process was given over the full length. By adopting the heat insulating tube 20 having flexibility in this way, the low temperature insulated superconducting cable 100 can be easily bent at the time of transportation or laying. Furthermore, by forming the heat insulating tube 20 with a corrugated tube, the heat stress can be reduced by deformation when the heat insulating tube 20 is cooled by the refrigerant 131 and thermally contracts.

[Sheet material]
Next, characteristics required for the sheet material 2 used in the cable laying method will be described. Since the sheet material 2 is pulled in a state where the low-temperature insulated superconducting cable 100 is placed thereon, it is required to have a tensile strength that does not break by the pulling. The tensile strength required for the sheet material 2 is unambiguous because it varies depending on the length of the conduit 8, the degree of bending of the route, the frictional force between the conduit 8 and the sheet 2, the weight of the low-temperature insulated superconducting cable 100, and the like. Cannot be determined.

  Further, since the sheet material 2 is slid in the pipe line 8, it is preferable that the friction coefficient of the surface (sliding surface) on the pipe line 8 side in the sheet material 2 is small. When the friction coefficient of the sliding surface of the sheet material 2 is reduced, the frictional resistance between the sheet material 2 and the pipe line 8 is reduced, and the laying tension of the sheet material 2 can be reduced. As a result, it is possible to reduce the possibility of problems such as breakage of the sheet material 2. Specific examples of the friction coefficient of the sliding surface of the sheet material 2 include 0.3 or less. The friction coefficient of the sliding surface is more preferably 0.2 or less, and the friction coefficient of the sliding surface is further preferably 0.1 or less.

  When the elongation of the sheet material 2 at the time of laying is less than or equal to the allowable elongation of the cable 1, the friction coefficient of the surface (mounting surface) on the cable 1 side of the sheet material 2 may be large or small. If the friction coefficient of the mounting surface of the sheet material 2 is large, the cable 1 moves integrally with the sheet material 2 when the sheet material 2 is pulled. On the other hand, if the friction coefficient of the mounting surface of the sheet material 2 is small, the cable 1 slides on the sheet material 2 when the sheet material 2 is pulled. In this case, the cable 1 is drawn into the pipe line 8 after the movement of the sheet material 2.

  When the elongation of the sheet material 2 at the time of laying is equal to or greater than the allowable elongation of the cable 1, when the cable 1 and the sheet material 2 move together, the cable 1 is stretched beyond the allowable elongation. Damage may occur. Therefore, when the sheet material 2 is easy to extend, the friction coefficient of the mounting surface of the sheet material 2 is reduced, and the cable 1 is slid on the sheet material 2 so that the cable 1 does not extend beyond the allowable elongation. As a specific friction coefficient of the mounting surface of the sheet material 2 for achieving this configuration, for example, 0.3 or less can be mentioned. The friction coefficient of the mounting surface is more preferably 0.2 or less, and the friction coefficient of the mounting surface is further preferably 0.1 or less.

  A fluororesin can be mentioned as a material of the sheet | seat material 2 provided with the characteristic demonstrated above. Fluororesin generally has a low coefficient of friction. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and tetrafluoroethylene / ethylene copolymer. Examples thereof include ETFE, polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and chlorotrifluoroethylene / ethylene copolymer (ECTFE). In addition, examples of the material of the sheet material 2 include polophenylene sulfide (PPS) and carbon fiber reinforced plastic. These materials are excellent in tensile strength.

  Here, when the friction coefficients of the sliding surface and the mounting surface of the sheet material 2 are made different, for example, the sheet material 2 has a two-layer structure, and the materials constituting each layer are made different. For example, the high-strength sliding fiber from Gunze Co., Ltd. is a woven fabric in which a PFA layer, which is a low-friction material, and a PPS layer, which is a high-strength material, are integrated, and the surface on the PFA side is the sliding surface. The surface on the PPS side can be used as the mounting surface. In addition, the sheet material 2 having a different friction coefficient between the sliding surface and the mounting surface can be produced by applying a lubricant to the sliding surface of the single-layer sheet material 2.

  In addition, the sheet material 2 can have a three-layer structure in order to make the sheet material 2 difficult to break during towing and having a small friction coefficient between the sliding surface and the mounting surface. For example, the sheet | seat material 2 which provided the layer of the low friction material in the one surface side and other surface side of the layer of a high intensity | strength material can be mentioned. In addition, the sheet material 2 which is hard to break and has a small friction coefficient between the sliding surface and the mounting surface may be produced by applying a lubricant to both surfaces of the sheet material 2 made of a high strength material.

[Advantages when installing superconducting cables]
The low-temperature insulated superconducting cable 100 shown in FIG. Since the heat insulation pipe 20 is normally formed in a corrugated shape, it is easy to expand and contract. Further, the inner tube 21 and the outer tube 22 of the heat insulating tube 20 and the inner tube 21 and the cable core 10 are not in close contact with each other. Therefore, when pulling the low-temperature insulated superconducting cable 100, the outer tube 22 receives a frictional force with the duct 8, and the inner tube 21 and the cable core 10 are not easily affected by the frictional force. That is, the outer tube 22 that receives a frictional force when the low-temperature insulated superconducting cable 100 is pulled moves relative to the inner tube 21, and the inner tube 21 and the outer tube 22 come into contact with each other or between the tubes 21 and 22. There is a possibility that the heat insulating material of the heat insulating pipe 20 is remarkably deteriorated. Further, the heat insulating tube 20 (particularly, the outer tube 22) itself may be damaged. For this reason, conventionally, a tension member is provided outside the heat insulating tube 20 and the laying tension of the low-temperature insulated superconducting cable 100 is shared by the tension member. However, according to the cable laying method according to the embodiment, since the stress acting on the low-temperature insulated superconducting cable 100 is reduced, it is not necessary to provide a tension member outside the heat insulating tube 20. The low-temperature insulated superconducting cable 100 is considered to be installed in the existing pipeline instead of the existing normal conducting cable, and the installation space of the low-temperature insulated superconducting cable 100 in the pipeline is limited. However, if the cable laying method according to the embodiment eliminates the need to provide a tension member in the low-temperature insulated superconducting cable 100, the dimensional constraints of the low-temperature insulated superconducting cable 100 that can be laid in the pipe line can be relaxed.

  Here, in addition to pulling the sheet material 2 by placing the low-temperature insulating superconducting cable 100 on the sheet material 2, the corrugated outer tube 22 of the cable 100 is reinforced or the outer tube 22 is reinforced. A structure that increases the vertical rigidity of the plate may be employed. Examples of the former include a configuration in which the trough is reinforced with a filler filling the trough, a string-like body wound spirally around the trough, and the outer tube 22 is prevented from compressive deformation. Examples of the latter include, for example, (a) a structure in which the height of at least some of the peaks is smaller than the depth of the valley, and (b) the depth of at least some of the valleys is smaller than the height of the peaks. (C) a structure in which the width of at least some of the peaks is longer than the width of the valley, and (d) a structure in which the width of at least some of the valleys is longer than the width of the peaks. Can do. By making the outer tube 22 difficult to deform in this way, the properties (tensile strength, etc.) required for the sheet material 2 used for laying are alleviated, the cost of the sheet material 2 is reduced, and the laying cable length is increased. You can.

<Embodiment 2>
The method of laying a cable through the sheet material described in the first embodiment can also be used for laying a normal conducting cable such as a room temperature insulated superconducting cable, an OF cable, or a CV cable. Even in this case, the stress acting on the cable can be reduced.

  The cable laying method can be suitably used for forming a large current transmission network.

DESCRIPTION OF SYMBOLS 1 Cable 2 Sheet | seat material 3 Winding device 4 Pulling wire 5 Pulling member 8 Pipe line 100 Low temperature insulation type superconducting cable 10 Cable core 11 Former 12 Superconducting conductor layer 13 Insulating layer 14 Outer conductor layer 15 Protective layer 20 Heat insulating pipe 21 Inner pipe 22 Outer tube 131 Refrigerant

Claims (7)

A cable laying method for laying a cable in a pipeline,
A cable laying method in which a sheet material is interposed between the cable and the conduit, and the cable placed on the sheet material is pulled into the conduit by pulling the sheet material.   The cable laying method according to claim 1, wherein an elongation of the sheet material at the time of laying is equal to or less than an allowable elongation of the cable. The elongation of the sheet material during laying is equal to or greater than the allowable elongation of the cable,
The cable laying method according to claim 1, wherein the cable is pulled into the pipe line as the sheet material is pulled while sliding the cable on the sheet material.   The cable laying method according to claim 3, wherein a friction coefficient of the sheet side surface of the sheet material is 0.3 or less.   The cable laying method according to any one of claims 1 to 4, wherein a friction coefficient of a surface on the pipe line side in the sheet material is 0.3 or less.   The cable laying method according to any one of claims 1 to 5, wherein, on the supply side of the cable, the outer periphery of the cable is sandwiched and the cable is pushed into the pipeline.   The said cable is a low-temperature insulation type superconducting cable provided with the cable core which has a superconducting conductor and the insulating layer arrange | positioned on the outer periphery, and the heat insulation pipe | tube which accommodates the said cable core inside. The cable laying method according to any one of the above.

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