JP2009016221A - Solid type cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid cable having a large effect of suppressing movement of an insulation oil. <P>SOLUTION: The solid cable 1 includes an insulation layer (main insulation layer 12m) at the outer circumference of a conductor 10. The main insulation layer 12m has an oil movement suppression part 12m<SB>p</SB>in which an insulating member is wound around so that a part of the insulating member to form an adjoining turn may be overlapped, and the portion other than the suppression part 12m<SB>p</SB>is constructed of a gap winding. Since the oil movement suppression part 12m<SB>p</SB>has a higher resistance to oil movement compared with the portion consisting of the gap winding, movement of insulation oil to the outer circumference side of the insulation layer 12 and the longitudinal direction of the cable 1 can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid cable having an insulating layer impregnated with insulating oil. In particular, the present invention relates to a solid cable that can effectively suppress the movement of insulating oil in the radial direction and longitudinal direction of the cable.

As a long-distance large-capacity power cable, a solid cable including an insulating layer impregnated with a relatively high viscosity insulating oil is used. The insulating layer is formed by winding an insulating material such as kraft paper or a composite tape made of kraft paper and a plastic film (see, for example, Patent Documents 1 and 2). Usually, performed gap winding winding the insulating material to allow a gap g between the insulating material I _n, I _{n + 1} to make the turn (n, n + 1) adjacent as shown in FIG. 6 (II) Each time a predetermined number of insulating materials are wound in a uniform winding direction, the insulating layer is formed by reversing the winding direction of the insulating material, so that predetermined mechanical properties (for example, bending, twisting, etc.) and strength So that the cable has

  The plastic portion constituting the composite tape hardly allows the insulating oil to pass through, but the kraft paper portion allows the insulating oil to pass therethrough, so that it becomes a passage for the insulating oil. In addition, a gap formed between the composite tapes that are abutted together and a gap that is formed by overlapping the gaps up and down also serve as an insulating oil passage.

  When energization of the solid cable is started, the temperature of the conductor first rises, and as the temperature of the conductor rises, the temperature of the inner peripheral side (conductor side) of the insulating layer rises before the outer peripheral side (sheath side). As the temperature rises, the insulating oil expands and the viscosity decreases. The insulating oil expanded as the temperature rises moves in the radial direction of the cable from the inner peripheral side to the outer peripheral side of the insulating layer so that the hydraulic pressure in the insulating layer becomes uniform. When the load current is cut off or reduced from this state, the temperature of the conductor having a higher temperature than the outer peripheral side of the insulating layer first decreases. Thereafter, the heat gradually reduces the temperature on the inner and outer peripheral sides of the insulating layer. The insulation oil contracts due to this decrease in temperature. Due to this shrinkage, the insulating oil tends to return from the outer peripheral side to the inner peripheral side, but the outer peripheral side of the insulating layer has a low temperature and the viscosity of the insulating oil is high, so the insulating oil is difficult to return to the inner peripheral side. May occur. In addition, the movement of the insulating oil from the inner peripheral side to the outer peripheral side of the insulating layer exerts pressure in a direction that widens the insulating oil passages (holes in the fibers constituting the kraft paper and the above-described gaps (oil gaps)). However, the movement of the insulating oil from the outer peripheral side to the inner peripheral side is difficult to move because the pressure acts in the direction of narrowing the passage. As a result, particularly in the insulating layer, the hydraulic pressure immediately above the conductor becomes negative pressure, and an oil exhausted state (typically, a void) may occur in this portion. In particular, if the insulating oil is exhausted continuously in the radial direction or the longitudinal direction of the cable, there is a risk of electrical breakdown due to electric discharge.

  The solid cable described in Patent Document 3 is configured to be impregnated with a medium viscosity insulating oil so that the vicinity of the conductor does not become a negative pressure when the load is interrupted or the like, thereby reducing the generation of voids.

JP 11-149831 A Japanese Patent Laid-Open No. 2001-23449 Japanese Patent Laid-Open No. 11-224546

  If the viscosity of the insulating oil is lowered, it is possible to make it difficult for oil-depleted conditions to occur. However, if the viscosity is lowered too much, the insulating oil leaks from the end of the cable or damaged parts during manufacturing or installation, or the insulating oil flows out when the metal sheath is peeled off when connecting the cables. There's a problem. Therefore, to reduce the occurrence of oil-depleted states such as voids, it is effective to suppress oil movement itself. However, the structure which suppresses oil movement more effectively is not fully examined conventionally.

  The insulating oil moves not only in the radial direction of the insulating layer but also in the longitudinal direction of the cable. Therefore, for example, if the cable has a height difference on the terrain of the cable installation location, the insulating oil that has moved to the low place side is unlikely to return to the high place side due to gravity, and a large void tends to be generated on the high place side.

  Therefore, one of the objects of the present invention is to provide a solid cable having a high effect of suppressing the movement of insulating oil.

The present invention does not constitute the entire insulating layer by gap winding, but a part of the insulating materials I _n and I _{n + 1} that form adjacent turns (n, n + 1) as shown in FIG. The above-mentioned object is achieved by providing a part of the insulating layer with a portion formed by winding the insulating material so as to overlap. Specifically, the solid cable of the present invention includes an insulating layer formed by winding an insulating material around the outer periphery of a conductor, and is formed by winding an insulating material so that a part of the insulating material forming an adjacent turn overlaps. The oil movement suppressing portion is provided in the insulating layer.

Examples of the method of winding the insulating material so that a part of the insulating material that forms adjacent turns overlap each other include lap winding and co-winding. The lap winding, in forming a sequential-turn feeding one insulating material, as shown in FIG. 6 (I), a part of the insulating material I _n make certain turns (n), the next turn (n This is a method in which the insulating material In _{+ 1} for creating +1) is overlapped and wound. The cowound, in forming the turn alternately feeding alternately two insulation, a portion of one of the insulation I _n make certain turns (n), making the next turn (n + 1) In this method, the other insulating material In _{+ 1} is overlapped and wound. The overlap allowance for overlapping the insulating materials that form adjacent turns can be selected as appropriate, and it is considered that half or less of the width of the insulating material is sufficient.

FIG. 1 is a cross-sectional view schematically showing an insulating layer formed by winding a composite tape, where (I) is an example of a combination of lap winding or co-winding and gap winding, and (II) is only gap winding. An example of When a plurality of composite tapes T formed by laminating kraft paper C on both sides of a plastic film P are wound in a gap and stacked, as shown in FIG. A gap g created between adjacent turns T _n and T _{n + 1} exists in a straight line in the thickness direction of the tape T. For example, the insulating oil that has passed through the gap g ₁₀₁ between the first turn T ₁₀₁ and T ₁₀₂ moves in the longitudinal direction of the cable through the kraft paper C portion on the outer peripheral side of the first tape T. Specifically, the insulating oil moves in the direction indicated by the black arrow from the x mark in FIG. Further, by this movement, the insulating oil moves to the third sheet through the gaps g _102-1 , g _102-2 , g _102-3 ... _Formed by the second tape T. Insulating oil thus passes through the gap g between the turns of each tape and the kraft paper C portion in order from the inner peripheral side to the outer peripheral side (the direction indicated by the white arrow in FIG. 1 (II)), and the length of the cable. Move in the direction.

On the other hand, the portion formed by wrapping or co-winding the tape T (hereinafter referred to as lap winding) has two gaps created between adjacent turns T ₁ and T _{2 as} shown in FIG. gap g _1-1, are divided into g _1-2, the oil gap is made stepwise. As described above, in the lap winding, the oil gap can be stepped, and the oil passage can be lengthened and resistance to oil movement can be increased as compared with the gap winding in which the oil gap is straight.

Also, the insulating oil that has passed through the second gap g ₁₀₁ composed of the gap winding moves in the longitudinal direction of the cable through the kraft paper C portion on the outer peripheral side of the second tape T as described above. Then, go to the gap g _1-1 of the third piece, which consists of wrapping. The insulating oil that has passed through the gap g _1-1 moves toward one side in the longitudinal direction (left side in FIG. 1 (I)) as shown by the black arrow in FIG. 1 (I), and passes through the kraft paper C portion. Try to pass through gap g _1-2 . However, each turn formed by lap winding or the like is at least partially pressed against the tape of the next turn, so the kraft paper C at the contact point in the adjacent turn is in close contact with each other, and the gap g _1-1 It is difficult for insulating oil to move from the gap to g _1-2 . That is, the insulating oil is difficult to move in the longitudinal direction and the radial direction of the cable in a portion composed of lap winding or the like.

  The cable of the present invention can have a portion (first oil movement restraining portion) where resistance to oil movement is large and the insulating oil hardly moves by changing how the insulating material is wound in a part of the insulating layer. Therefore, the cable of the present invention can effectively reduce the movement of the insulating oil on the inner peripheral side from the oil movement suppressing portion to the outer peripheral side via the suppressing portion. That is, in the cable of the present invention, the insulating oil moves mainly in the range from the inner peripheral side of the insulating layer to the oil movement suppressing portion. By restricting the movement range of the insulating oil in this way, the cable of the present invention can suppress the occurrence of an oil-depleted state such as a void accompanying the oil movement. Moreover, since the cable of the present invention reduces the movement of the insulating oil not only in the radial direction of the cable but also in the longitudinal direction, it is possible to effectively reduce the formation of large voids.

  If the entire insulating layer is formed by lap winding or the like, the oil passage can be made longer and the resistance to oil movement can be made higher, which is preferable from the viewpoint of suppressing oil movement. However, this configuration has problems such as deterioration in mechanical properties such as bending and wrinkling of the insulating layer. Therefore, the cable of the present invention is configured by combining gap winding and lap winding.

  The main insulating layer excluding the semiconductive layer in the insulating layer is formed using at least one of insulating paper and a composite tape made of insulating paper and a plastic film. In particular, since the composite tape has a greater resistance to oil movement than an insulating paper such as kraft paper, the main insulating layer made of the composite tape has a radial direction of the cable and the main insulating layer made only of the kraft paper. It is difficult to move the insulating oil in the longitudinal direction. Therefore, the main insulating layer preferably includes a portion made of a composite tape, and more preferably mainly made of a composite tape. If the entire main insulating layer is composed of a composite tape, the innermost and outermost layers of the main insulating layer may cause electrical breakdown due to high electrical stress. Therefore, at least a part of the main insulating layer may have a portion made of a material having a resistivity (ρ) smaller than that of the composite tape, typically kraft paper.

  For example, the main insulating layer has a configuration in which a portion made of a composite tape and a low ρ portion made of a low ρ material are combined. The low ρ portion is provided on at least one of the inner peripheral side of the composite tape portion and the outer peripheral side of the main insulating layer. By providing the main insulating layer with a low ρ portion, the stress is high in the composite tape portion, and the stress received by the portion susceptible to the influence of the conductor can be reduced, and a cable having excellent insulation performance can be obtained. When the low ρ portion is provided on both the inner peripheral side and the outer peripheral side of the main insulating layer, it is possible to obtain a cable that is superior in insulation performance. Or the structure which arrange | positioned the kraft paper suitably between composite tapes is mentioned. By placing kraft paper between relatively hard composite tapes, it can be expected that kraft paper will function as a cushioning material. Since kraft paper becomes an oil passage as described above, it is preferable that the kraft paper is as small as possible in consideration of an improvement in the effect of suppressing oil movement. Therefore, the number of kraft paper wound as a cushioning material is preferably 3 or less, particularly 1 to 2 sheets.

  As the composite tape, for example, a polyolefin resin film in which kraft paper is arranged on at least one surface can be used. The polyolefin resin is preferably polypropylene having excellent insulating performance. The thickness of the composite tape is practically 50 to 200 μm, preferably 100 to 150 μm.

  In addition, composite tapes having various ratios k of the thickness of the plastic portion to the thickness of the tape can be used. For example, it is good also as a structure from which the ratio k differs in the thickness direction of an insulating layer using the multiple types of composite tape from which the ratio k differs. That is, when a group formed by winding composite tapes having the same ratio k is the same k value portion, the main insulating layer may have a plurality of identical k value portions having different ratios k.

  The main insulating layer has at least one oil movement restraining portion (first oil movement restraining portion) composed of lap winding or co-winding, and a plurality of oil movement restraining portions are provided at intervals in the main insulating layer. It may be provided. Portions other than the first oil movement suppression portion in the main insulating layer are configured by gap winding.

  The oil movement suppression part is preferably composed of a composite tape, particularly a tape having a ratio k of 40 to 80%. A composite tape with a high ratio k has a high resistance to oil movement because there are few kraft paper parts impregnated with insulating oil. If this tape constitutes the first oil movement suppression part, in addition to the insulating material winding structure, Thus, combined with the high resistance of the composite tape itself to oil movement, the oil movement suppression effect can be further enhanced. Further, a composite tape having a high ratio k tends to have a high insulation resistance in the tape. Therefore, in consideration of improvement in oil movement suppression effect and improvement in insulation performance, the ratio k is preferably 60% or more, particularly preferably 65% or more and less than 80%. On the other hand, a tape with a low ratio k is relatively inexpensive, and the manufacturing cost can be reduced by using such a tape. Further, a tape with a low ratio k is easy to be impregnated with insulating oil due to an increase in the insulating paper portion, and is excellent in cable manufacturability. Therefore, in consideration of manufacturing cost and manufacturability, the ratio k is preferably less than 60%. In the case where the insulating layer includes a plurality of oil movement suppression units, the ratio k of the composite tapes constituting each suppression unit may be different. Further, when the oil movement suppression unit is composed of a composite tape, the adjacent insulating material is preferably a composite tape having a higher oil movement suppression effect than insulating paper such as kraft paper.

  The thickness in the radial direction of one first oil movement suppression portion is expressed by (thickness of one insulating material × 2) × number of windings, and by adjusting the number of windings, a desired thickness Can be. The thicker the oil movement suppression part, the higher the oil movement suppression effect tends to be.However, a sufficient effect can be achieved even with a size of three or less insulation materials, especially one or two. It is thought to have.

  Here, the winding direction of the insulating material constituting the main insulating layer is not particularly limited, but the main insulation is achieved by combining the two winding directions rather than forming the entire insulating layer only in one direction, that is, only in the clockwise direction or only in the counterclockwise direction. It is preferable to constitute the layer. In particular, when a bundle formed by winding a predetermined number (for example, five to ten or more) in a uniform direction is a one-way winding layer, the main insulating layer is composed of a plurality of one-way winding layers and adjacent to each other. It is preferable that the wound layers to be configured have different winding directions of the insulating material. That is, when a configuration in which a right-handed unidirectionally wound layer (hereinafter referred to as a right-handed layer) and a left-handed unidirectionally wound layer (hereinafter referred to as a left-handed layer) alternately appear at a predetermined interval, It is preferable because of its excellent characteristics. One unidirectional winding layer may be composed only of a composite tape, or may be composed of a portion composed of a composite tape and a portion composed of the above-described low rho material. The oil movement suppression unit can exist at any position of such an insulating layer, and may be in any winding direction.

  In particular, when the main insulating layer has a configuration in which a right-handed layer and a left-handed layer appear alternately, the first oil movement suppression portion is a portion where the winding direction of the insulating material changes (layer changing portion), that is, from the right-handed winding. It is preferable that it exists in the part which changes from left-handed or left-handed to right-handed. FIG. 2 is an explanatory view schematically showing a state in which insulating materials having different winding directions are wound, and (I) is a one-way winding formed by gap winding in either a right-handed winding or a left-handed winding. A state in which a unidirectionally wound layer is formed on the wound layer with a gap wound in the other winding direction; (II) is a top of the unidirectionally wound layer formed with a gap wound in either one of the wound directions; A state in which a unidirectionally wound layer is formed by overlappingly winding in the same winding direction, and (III) is configured such that the other winding is formed on the unidirectionally wound layer formed by gap winding in either one of the winding directions. The state which comprises the one-way winding layer formed by overlappingly winding in a direction is shown.

When a unidirectionally wound layer is formed by gap winding, the next insulating material can be wound so as to cover the gap between the abutted insulating materials. However, when the winding directions of the adjacent winding layers are different, the outermost portion of the lower winding layer 200u as shown in FIG. And an insulating material (indicated by a thick solid line in FIG. 2 (I)) that forms the innermost side of the upper winding layer 200o provided on the insulating material (shown by a thin broken line in FIG. 2 (I)). Arranged to intersect. Further, the oil gap g _u existing on the outermost side of the lower winding layer 200u and the oil gap g _o existing on the innermost side of the upper winding layer 200o are provided so as to intersect with both oil gaps g _u. , g _oo partly communicates with g _o . Therefore, oil movement is likely to occur in the layer change portion. Therefore, oil movement can be more effectively suppressed by providing the first oil movement suppression portion made of lap winding or the like in such a portion. Therefore, the inner circumferential side unidirectional winding layer (hereinafter referred to as the inner winding layer) and the outer circumferential side unidirectional winding layer (hereinafter referred to as the outer winding layer) adjacent to the first oil movement suppression portion. Both of them preferably have a configuration in which the winding direction of the insulating material is different from each other. With such a configuration, the first oil movement suppression portion m _p (indicated by a thick solid line and a thick broken line in FIG. 2 (II)) is disposed on the adjacent lower winding as shown in FIG. 2 (II). Even in the same winding direction as the winding layer (inner winding layer) 200u, the winding direction different from the adjacent inner winding layer 200u as shown in FIG. 2 (III) (the same winding direction as the outer winding layer not shown) is also described above. There is no communication part.

  Although the number of the oil movement suppressing portions may be one in the insulating layer, the oil movement suppressing effect can be enhanced by providing a plurality of oil movement suppressing portions. In the case of a plurality, for example, one first oil movement suppression unit may be provided for one unidirectionally wound layer.

  The portion of the main insulating layer excluding the oil movement suppressing portion is preferably composed of a composite tape having a small ratio k, particularly a tape having a ratio k of less than 60%, because it is relatively inexpensive and can reduce costs. In addition, the portion excluding the oil movement suppression unit may have a configuration in which the ratio k is sequentially different, that is, a so-called ρ grading configuration. Here, when a group formed by winding a tape with a uniform ratio k is the same k value portion, it is preferable that the thicknesses of the same k value portions constituting the ρ grading are substantially equal. For example, when ρ grading is applied to the entire main insulating layer excluding the oil movement suppressing portion, the thickness of each same k value portion is a thickness obtained by dividing the thickness of the main insulating layer excluding the oil movement suppressing portion equally. To do.

  As described above, if all the parts of the main insulating layer except the oil movement suppression part are composed of the composite tape having a small ratio k, the manufacturing cost can be reduced most. A region to be configured may be separately provided in the main insulating layer. For example, the inner peripheral side region in the main insulating layer near the conductor (or inner semiconductive layer) or the outer peripheral side region in the vicinity immediately below the sheath (or outer semiconductive layer) may be configured with a tape having a high ratio k. The inner peripheral area is an area where electrical stress increases at normal temperature (no load or low load), and the outer peripheral area is an area where electrical stress increases at high temperatures (load). Providing a high-k portion made of tape makes it difficult for the insulating layer to break down electrically. The oil movement suppression part is composed of a tape with a high ratio k, and the inner layer side, the intermediate part, and the outer periphery side of the insulating layer are provided with parts made of tape with a high ratio k (oil movement suppression part and high k part). Then, the effect of suppressing the movement of the insulating oil and reducing electric breakdown is high. The high k portion is formed by winding one or two tapes having a high ratio k in consideration of electrical characteristics, for example.

  In order to further improve the degree of improvement in insulation performance and the effect of suppressing oil movement, instead of a tape with a high ratio k, or a combination with a tape with a high ratio k, a plastic tape consisting only of a plastic film, such as a polypropylene tape, is used. It is effective to form an oil movement suppression part and a high k part by using. By using the plastic tape, the ratio of the plastic portion in the oil movement suppressing portion and the high k portion can be increased.

  When the main insulating layer is composed of a plurality of composite tapes having different ratios k, that is, when there are a plurality of the same k value portions in the main insulating layer, the first oil movement suppression composed of lap winding or the like in the main insulating layer It is good also as a structure which provides separately the 2nd oil movement suppression part which consists of a composite tape with a high ratio k in addition to a part. Specifically, a 2nd oil movement suppression part is comprised from the following same k value part among several same k value parts. The same k value part constituting the second oil movement suppression part is the same k value part on the inner peripheral side (hereinafter referred to as the inner k value part) adjacent to the same k value part and the same k value part on the outer peripheral side. The ratio k is higher than (hereinafter referred to as the outer k value portion) and is thinner than at least one of the adjacent inner k value portion and outer k value portion. In addition, the same k value part which becomes the inner k value part and the outer k value part adjacent to the second oil movement suppression part is the second in addition to the same k value part adjacent to the second oil movement suppression part. The portion made of the low ρ material described above is adjacent to the oil movement suppressing portion, and includes the same k value portion adjacent to the portion made of the low ρ material.

  The second oil movement suppressing portion can be formed by merely making the type of composite tape (the size of the ratio k) different from the other portions of the main insulating layer. Such a second oil movement suppression part can also be present at any position of the main insulating layer, but can be present in the layer change part as well as the first oil movement suppression part by the above-described lap winding or the like. preferable. Further, the composite tape constituting the second oil movement restraining portion preferably has a ratio k of 60% or more, particularly 65% or more and less than 80%. Although the number of the second oil movement suppression units may be one, the oil movement suppression effect can be enhanced by the presence of a plurality of the second oil movement suppression units. One second oil movement suppression part can be configured by winding three or less composite tapes having a high ratio k, in particular, 1-2 sheets.

  To form a mixed structure of gap winding and lap winding, for example, the width of the insulating material used for lap winding is made wider than the width of the insulating material used for gap winding, or the pitch of the insulating material during winding is adjusted. To do. For example, when the insulating layer is formed using a winding device that automatically winds the insulating material, the pitch and the like can be adjusted by adjusting the winding device. Examples of the winding device include a winding device group including a plurality of winding machines arranged along the traveling direction of the conductor. Each winding machine includes a winding head having an annular head portion disposed on the outer periphery of a traveling conductor (or internal semiconductive layer) and a plurality of pads held by the head portion. The head portion has a through hole through which a conductor is inserted at the center thereof, and holds a plurality of pads at intervals so as to be arranged in an annular shape outside the through hole. Each pad supports one wound insulating material and sequentially feeds the insulating material to the conductor passing through the through hole. The winding device is configured by arranging the winding machines so that the through holes of the respective winding machines are arranged coaxially. The pitch can be adjusted by adjusting the distance between these winding machines. By preparing a winding machine that performs lap winding and a winding machine that performs gap winding, a mixed structure can be formed. Alternatively, the mixed structure can be formed by adjusting the spacing between two or more pads in one winding machine and changing the pitch of two or more insulating materials. In this case, in one winding machine, there are a pad that performs lap winding and a pad that performs gap winding. In order to form a mixed structure of gap winding and co-winding, a winding machine that performs a gap winding with a pad that feeds out one insulating material and a pad that alternately feeds two insulating materials are used for co-winding For example, a winding machine is prepared.

  The solid cable of the present invention can effectively suppress oil movement in the insulating layer.

Embodiments of the present invention will be described below.
(Example 1)
FIG. 3 is a cross-sectional view of the solid cable of the present invention. In the following drawings, the same reference numerals indicate the same items. The solid cable 1 includes a conductor 10, an insulating layer 12 (an inner semiconductive layer 11, a main insulating layer 12m, an outer semiconductive layer 13), and a metal sheath 14 in order from the center. The most characteristic feature of the cable 1 is the configuration of the main insulating layer 12m. Hereinafter, this point will be mainly described.

The main insulating layer 12m is composed of a composite tape in which kraft paper is laminated on both sides of a polypropylene (PP) film, specifically, PPLP (registered trademark of Sumitomo Electric Industries, Ltd.) spirally wound in multiple layers. The In this example, the main insulating layer 12m is formed by using a PPLP (registered trademark) thickness ratio k of about 40% (thickness 125 μm). The main insulating layer 12m is, PPLP formed by winding superposed ® oil shift suppressing portion (the first oil shift suppressing portion) 12m _p and the inner insulating portion 12m _i and an outer insulating portion formed by winding gap Composed of 12m _o . The insulating layer 12 is impregnated with an insulating oil having a viscosity of 10 to 500 cst at 60 ° C., for example.

Oil shift suppressing portion 12m _p is mainly insulating layer located in the middle part of 12m, sandwiched between the inner insulating portion 12m _i and an outer insulating portion 12m _o. In this example, it constitutes a suppressing portion 12m _p performing lap winding in one PPLP (registered trademark). In other words, suppression portion 12m _p, the thickness of the radial direction is equal to PPLP (registered trademark) of one thick × 2. 3 to 5 show the oil movement suppression unit in an exaggerated manner.

Each inner insulating portion 12m _i and an outer insulating portion 12m _o, constitute the remainder except for the oil shift suppressing portion 12m _p in the main insulating layer 12m, made by turning a predetermined number of volumes PPLP (registered trademark) in a uniform direction unity Is made of a plurality of unidirectionally wound layers. Further, both portions 12m _i, 12m _o are each configured as the winding direction of the adjacent winding layer are different from each other. The suppression portion 12m _p is both portions 12m _i, among a plurality of unidirectional winding layer constituting the 12m _o, two unidirectional winding layer winding direction is changed portion (the layer of the adjacent suppressing portion 12m _p It is arranged in the changing part). Winding direction of PPLP constituting the suppressing portion 12m _p (R) is equal to the one of the two one-way winding layer adjacent to the suppressing portion 12m _p. In addition, each one-way winding layer constituting both parts 12m _i, 12m _o is formed by turning a dozen sheets winding the PPLP (registered trademark).

The solid cable 1 having the above configuration is superior in insulation performance and oil performance by forming the main insulation layer 12m with a composite tape such as PPLP (registered trademark) compared to the case where the main insulation layer is formed with kraft paper. High resistance to movement. In particular, the cable 1 is an oil shift suppressing portion 12m _p with enhanced resistance to oil moved by lap winding that comprises the main insulating layer 12m, insulation on the outer peripheral side from the inner insulating portion 12m _i via the suppressing unit 12m _p It is possible to effectively suppress the movement of oil. Moreover, the cable 1, by comprising a suppression unit 12m _p in the layer instead part of the main insulating layer 12m, can be more effectively suppress the movement of the insulating oil. Therefore, the temperature rise of the conductor 10 insulating oil is restricted to the oil shift suppressing portion 12m _p even tries to move to the outer peripheral side of the insulating layer 12, the insulating oil of the inner insulating portion 12m _i from the conductor 10 to the suppressing portion 12m _p range, i.e., will mainly move through the inner insulating portion 12m _i. Therefore, in the cable 1, when the insulating oil contracts due to the temperature drop of the conductor 10, the insulating oil easily returns to the inner peripheral side, particularly in the vicinity of the conductor 10, and it is possible to reduce the occurrence of an oil-depleted state such as a void in the vicinity of the conductor 10. Insulating oil in the outer insulating portion 12m _o similarly will mainly move in the same part 12m _o. That is, the cable 1 can reduce the distance that the insulating oil moves in the radial direction of the cable 1. And, the cable 1, by comprising a suppression unit 12m _p consisting lap winding can be insulating oil also reduced to move in the longitudinal direction of the cable 1. By restricting the movement of the insulating oil in the insulating layer 12 in this way, the cable 1 can reduce the hydraulic pressure fluctuation.

  In addition, although Example 1 is configured to include one oil movement suppressing portion by lap winding in the main insulating layer, a plurality may be provided in the main insulating layer at appropriate intervals. At this time, it is possible to effectively suppress the insulating oil from moving to the outer peripheral side of the insulating layer because the oil movement suppressing portions due to the lap winding are present in multiple stages in the main insulating layer. In the case of a configuration including a plurality of oil movement suppression units, the ratio k of the composite tapes configuring each suppression unit may be the same or different. Further, the oil movement suppressing portion may be formed by co-winding instead of lap winding. These configurations can be similarly applied to Examples 2 and 3 described later.

In Example 1, a composite tape that constitutes the entire insulating layer 12, the ratio k although using the same proportion of oil shift suppressing portion 12m _p and the inner insulating portion 12m _i and an outer insulating portion 12m _o k May be composed of different tapes. For example, configure suppressing portion 12m _p using tape ratio k is higher than the composite tape which forms at least one inner insulating portion 12m _i and an outer insulating portion 12m _o, a plurality of kinds of composite tape proportion k is different Both portions 12m _i and 12m _o may be configured. That is, the main insulating layer 12m may be composed of a plurality of the same k value portions having different ratios k when a group formed by winding a tape having the same ratio k is the same k value portion. For example, the grading may be performed on the main insulating layer 12m by sequentially changing the ratio k in the radial direction of the cable. In the ρ grading, the resistivity may be increased from the inner peripheral side to the outer peripheral side of the main insulating layer 12m, or the resistivity may be increased from the outer peripheral side to the inner peripheral side. . If any of the composite tapes used has a low ratio k, for example, less than 60%, the manufacturing cost can be reduced. This configuration can be similarly applied to Examples 2 and 3 described later.

Moreover, apart from the oil shift suppressing portion 12m _p forming the insulating material in a particular winding configuration comprising an oil shift suppressing portion formed in one of the particular type as the insulating material (second oil shift suppressing portion) It is good. When the main insulating layer 12m is composed of a plurality of composite tapes having different ratios k, the second oil movement suppression unit is configured by gap-wrapping a tape having a high ratio k. Specifically, when there are a plurality of the same k value portions in the main insulating layer 12m, the following one of the plurality of the same k value portions is defined as a second oil movement suppression portion. The same k value part that constitutes the second oil movement suppression part has a higher ratio k than the same k value part on the adjacent inner peripheral side and the outer peripheral side, and more than at least one of the two adjacent same k value parts. Also assume that the thickness is thin. The second oil movement suppression unit can be easily configured only by changing the type of tape (the magnitude of the ratio k). By the presence of a second oil shift suppressing portion in at least one of the first oil shift suppressing portion 12m inner insulating portion in addition to the _p 12m _i and an outer insulating portion 12m _o, it is more enhanced oil transfer inhibiting effect. A plurality of second oil movement suppression units may be provided at appropriate intervals. This configuration can be similarly applied to Examples 2 and 3 described later.

(Example 2)
Next, a configuration including a main insulating layer made of composite tapes having different ratios k will be described. FIG. 4 is a cross-sectional view of the solid cable of the present invention including an oil movement suppressing portion and two high k portions by overlapping winding on the main insulating layer. The basic configuration of the solid cable 2 is the same as that of the solid cable 1 of Example 1, in order from the center, conductor 10, insulating layer 22 (inner semiconductive layer 11, main insulating layer 22m, outer semiconductive layer 13), A metal sheath 14 is provided. Main insulating layer 22m, the oil shift suppressing portion by lap winding (first oil shift suppressing portion) 22m _p and the inner insulating portion 22m _i, made of an outer insulating portion 22m _o, is formed by PPLP (registered trademark). The most characteristic feature of this cable 2 is that the ratio k of PPLP (registered trademark) constituting the main insulating layer 22m is partially different. Hereinafter, this point will be described, and the other points are the same as those of the first embodiment, and thus description thereof will be omitted.

Oil shift suppressing portion 22m _p, the ratio k is constructed by winding superposed about 40% of PPLP (registered trademark) is interposed between the inner insulating portion 22m _i and an outer insulating portion 22m _o. Each part 22m _i , 22m _o has a low k part (inner low k part 22m _il , outer low k part 22m _ol ) formed by gap-wrapping PPLP (registered trademark) with a ratio k of about 40%, and the ratio k is It is composed of a high-k portion (inner high-k portion 22m _ih , outer high-k portion 22m _oh ) formed by gap-wrapping about 70% PPLP (registered trademark).

Two high k portion 22m _ih, 22m _oh the inner low k unit 22m _il, exist as to sandwich the oil shift suppressing portion 22m _p, the unity an outer low-k unit 22m _ol. The inner high k portion 22m _ih is formed by winding PPLP (registered trademark) having a ratio k of about 70% on the inner semiconductive layer 11, and the outer high k portion 22m _oh is also having a ratio k of about 70%. PPLP (registered trademark) is wound on the outer low k portion 22 _mol . _{Each of} the high k portions 22m _ih and _22moh is configured by winding one or two PPLP (registered trademark). FIG. 4 exaggerates the high k portion.

Solid cable 2 having the above-described configuration, by comprising an oil shift suppressing portion 22m _p, can be suppressed oil movement in the same manner as in Example 1. In addition, the cable 2 has high k portions 22m _ih and 22m _oh with excellent insulation performance on both the inner and outer peripheral sides of the main insulating layer 22m, so that electrical breakdown is unlikely to occur at both normal and high temperatures. . The high k unit 22m _ih, 22m _oh the suppression portion 22m _p as well as suppression of oil movement can be expected.

(Example 3)
Next, a configuration in which the insulating layer includes an oil movement suppression part (first oil movement suppression part) and a low ρ part will be described. FIG. 5 is a cross-sectional view of the solid cable of the present invention having an insulating layer including an oil movement suppressing portion and a low ρ portion. The basic configuration of the solid cable 3 is the same as that of the solid cable 1 of Example 1, in order from the center, conductor 10, insulating layer 32 (inner semiconductive layer 11, main insulating layer 32m, outer semiconductive layer 13), A metal sheath 14 is provided. The most characteristic feature of this cable 3 is that the main insulating layer 32m has a composite tape portion 32c made of PPLP (registered trademark) and a low ρ portion made of kraft paper (inner low ρ portion 32i, outer low ρ portion 32o). It is in the point comprised from. Hereinafter, the description will focus on the low ρ portion, and since the other points are the same as those in the first embodiment, the description thereof will be omitted.

The main insulating layer 32m includes an oil movement suppressing portion (first oil movement suppressing portion) 32m _p formed by wrapping PPLP (registered trademark), an inner insulating portion 32m _i , and an outer insulating portion 32m _o formed by gap winding. It consists of.

The low ρ portion is provided on the inner peripheral side and the outer peripheral side of the main insulating layer 32m, and is configured by winding kraft paper. Inner low ρ portion 32i is formed on the inner semiconducting layer 11, the outer low ρ portions 32o are disposed on the outer insulating portion 32m _o of the main insulating layer 32m. Incidentally, the inner insulating portion 32m _i of composite tape portion 32c is disposed on the inner lower ρ unit 32i. The thickness of the inner low ρ portion 32i and the outer low ρ portion 32o is 5% of the thickness of the insulating layer 32, and the thickness of the main insulating layer 32m is 90% of the thickness of the insulating layer 32. FIG. 5 exaggerates the low ρ portion.

Solid cable 3 having the above-described configuration, by comprising an oil shift suppressing portion 32m _p, can be suppressed oil movement in the same manner as in Example 1. In addition, the cable 3 has low ρ low ρ portions 32i and 32o on the inner peripheral side and the outer peripheral side of the composite tape portion 32c formed of the composite tape. It is possible to reduce the stress at the location where the height is high and to prevent electrical breakdown. Therefore, the cable 3 is excellent in insulation performance.

  Example 3 is configured to have low ρ portions on the inner peripheral side and the outer peripheral side of the main insulating layer 12m shown in Example 1, but the inner peripheral side and the outer side of the main insulating layer 22m shown in Example 2 are used. It is good also as a structure which provides a low rho part on the inner peripheral side. By providing the low ρ portion in addition to the high k portion, this cable is more excellent in insulation performance.

  The above-described embodiments can be appropriately changed without departing from the gist of the present invention, and are not limited to the above-described configuration. For example, the oil movement suppression unit may be configured by winding a composite tape together.

  The solid cable of the present invention can be suitably used for power supply, particularly for long-distance and large-capacity power supply.

It is sectional drawing which shows typically the insulating layer formed by winding a composite tape, (I) shows the example which combined the overlap winding and the gap winding, and (II) shows the example of only gap winding. FIG. 6 is an explanatory view schematically showing a state in which insulating materials having different winding directions are wound, and (I) is a case where gaps are wound in different winding directions on a one-way winding layer formed by gap winding. A configuration comprising a directional winding layer, (II) is a state in which a unidirectional winding layer formed by laminating in the same winding direction is wound on a unidirectional winding layer formed by gap winding, III) shows a configuration in which a unidirectionally wound layer formed by lap winding in different winding directions is provided on a unidirectionally wound layer formed by gap winding. It is sectional drawing of this invention solid cable which equips the main insulation layer with one oil movement suppression part by overlapping winding. It is sectional drawing of this invention solid cable which provides the main insulation layer with the high k part and the oil movement suppression part by lap winding. It is sectional drawing of this invention solid cable which has an insulating layer which provides the low rho part and the oil movement suppression part by lap winding in the main insulating layer. It is a cross-sectional schematic diagram explaining the state which wound the insulating material, (I) shows lap winding or co-winding, and (II) shows gap winding.

Explanation of symbols

1,2,3 Solid cable 10 Conductor 11 Internal semiconductive layer
12, 22, 32 Insulation layer 12m, 22m, 32m Main insulation layer 12m _i , 22m _i , 32m _i inner insulation
12m _o , 22m _o , 32m _o Outer insulation 12m _p , 22m _p , 32m _p Oil movement restraint
13 Outer semiconductive layer 14 Metal sheath
22m _il inner low k part 22m _ol outer low k part 22m _ih inner high k part
22m _oh outer high k part 32i inner low ρ part 32o outer low ρ part 32c composite tape part
T Composite tape C Kraft paper P Plastic film I _n , I _{n + 1} Insulation material
T ₁ , T ₂ , T ₁₀₁ , T ₁₀₂ , T _n , T _{n + 1} turn g, g _1-1 , g _1-2 , g ₁₀₁ , g _102-1 , g _102-2 , g _102-3
g _u, g _o oil gap g _uo oil portion 200u lower winding layer of the gap are communicated with each other
200o Upper winding layer

Claims (3)

A solid cable having an insulating layer formed by winding an insulating material around the outer periphery of a conductor,
The said insulation layer is provided with the 1st oil movement suppression part formed by winding an insulating material so that a part of insulating material which makes an adjacent turn may overlap, The solid cable characterized by the above-mentioned. The insulating layer has a plurality of unidirectional windings when a bundle formed by winding a predetermined number of insulating materials in a uniform winding direction with a gap between the insulating materials forming adjacent turns is a one-way winding layer. With stratification,
2. The two unidirectional winding layers adjacent to the first oil movement suppression portion among the plurality of unidirectional winding layers are characterized in that the insulating material winding directions are different from each other. Solid cable. The insulating layer is
Insulating material includes a part formed by winding a composite tape made of insulating paper and plastic film,
When a group formed by winding a composite tape having the same ratio k of the thickness of the plastic part to the thickness of the composite tape is the same k value part, there are a plurality of identical k value parts having different ratios k,
2. The solid cable according to claim 1, further comprising a second oil movement suppression unit including the following same k value portion among the plurality of the same k value portions.
The same k value part constituting the second oil movement suppression part has a higher ratio k than the same k value part on the inner peripheral side adjacent to the same k value part and the same k value part on the outer peripheral side, and is adjacent to the same k value part. The thickness is thinner than at least one of the matching inner k side identical k value portion and outer circumference same k value portion.

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