JP5963168B2 - Power cable air termination connection - Google Patents

Description

  The present invention relates to an aerial terminal connection portion of a power cable.

Conventionally, the end of a power cable is accommodated in an epoxy pipe as a power cable air end connection (hereinafter referred to as a terminal connection), and the oil immersion type terminal connection is filled with insulating oil in the pipe. As shown in FIG. 8, in the terminal connection portion 110, the sheath 101, the shielding layer (not shown), the external semiconductive layer 102, the cable insulating layer 103, and the cable conductor 104 are exposed in order by stepping off. In this state, the terminal portion of the power cable 100 is accommodated in the soot tube 120.
A conductor lead bar 111 is attached to the exposed end of the cable conductor 104, and a copper metal tube 112 is attached from the sheath 101 to the outer semiconductive layer 102. A stress cone 113 is mounted from the outer semiconductive layer 102 to the cable insulating layer 103.

The soot tube 120 is a cylindrical body made of an insulating material, and an insulating oil 123 is sealed therein. And, on the outer peripheral surface of the tub tube 120, a cocoon-shaped umbrella portion 121 is formed so as to be lined up and down at substantially uniform intervals, and a flange 122 is provided at the lower end portion.
The upper metal fitting 114 that holds the conductor lead bar 111 described above is attached to the upper end portion side of the soot tube 120, and the lower metal fitting 115 that is joined to the flange 122 is attached to the lower end portion side of the soot tube 120. .
In addition, the soot tube 120 is supported by the gantry 117 via a support insulator 116 at a portion outside the lower metal fitting 115 of the flange 122.
In addition, a metal pipe 112 penetrating the center portion is attached to the lower metal fitting 115, and a tape winding layer 119 for oil stop is formed at the lower end portion of the metal pipe 112, and at the upper end portion of the metal pipe 112. Is provided with a tape winding layer 118 for cable shielding (see Patent Document 1).

JP 2008-027828 A

In the conventional terminal connection portion, in order to perform shielding from the metal tube 112 to the stress cone 113, the shielding tape is wound around the tape winding layer 118, and further, the pressing tape is wound from above. ing.
As shown in FIG. 9, these shielding tapes and presser tapes are arranged along the longitudinal direction of the power cable by a so-called wrap winding method in which the side edges in the tape width direction are overlapped with each other for each round of winding. It is wound.
When wrapping is performed in this way, there is a possibility that a gap V is generated due to the thickness of the tape at the overlapping portion of the tapes.
When such a gap V is present in each layer of the shielding tape or pressing tape, the air that has entered the gap V when the tape is wound gradually leaks into the insulating oil 123 as bubbles during operation of the power cable. Can be considered. When air bubbles leaking into the insulating oil 123 when the power cable 100 is energized move due to the convection of the insulating oil 123 and move to the vicinity of the stress cone 113 having a high potential gradient, discharge may occur. There is concern about the deterioration of the insulating properties.

  It is an object of the present invention to suppress the occurrence of discharge due to bubbles in the soot tube.

  The present invention relating to the air cable end connection part of the power cable includes a soot tube that contains the power cable end part and is filled with an insulating filler, and an external semiconductive layer exposed at the terminal end part of the power cable. A metal shielding layer formed by winding a shielding tape around and a pressing tape layer formed by winding a pressing tape from above the metal shielding layer, and the pressing tape is adjacent to each winding. The side edges of the tape and the side edges of the tape are tightly wound with no gap between each other, or the adjacent tape and the side edges of the tape are wound by gap winding with a gap provided between them.

In the above invention, the pressing tape is wound from above the metal shielding layer by butt winding or gap winding. When this pressing tape is butt-wound, even if there is a gap between adjacent tapes, it is opened. Similarly, when the gap winding is used, the gap between adjacent tapes is opened.
Therefore, in any case, when assembling the terminal connection portion, the air in the gap between the tapes is quickly exhausted, and air bubbles can be prevented from leaking between the tapes during operation of the power cable. That is, it is possible to suppress the generation of bubbles in the insulating filler during operation of the power cable, and it is possible to suppress discharge caused by the bubbles.

Further, in the above invention, the pressing tape may be wound with a wound winding that is sequentially stacked so that the direction of the spiral by the gap winding is opposite to that of the lower layer.
In that case, even when the tape and the tape overlap with each other due to the winding, the directions of the overlapping upper and lower tapes are different, so that the gap space can be prevented from being sealed. Therefore, the air in the gap can be easily degassed, and it is possible to suppress the generation of bubbles in the insulating filler during the operation of the power cable and to suppress the discharge caused by the bubbles. .

Further, in the above invention, a semiconductive tape layer formed by winding a semiconductive tape on the inner side of the pressing tape layer is provided, and the semiconductive tape is butt wound or wound around the power cable. You may make it wind by the said gap winding.
Also in this case, since the butt winding or the gap winding suppresses air from being trapped in the semiconductive tape layer, the generation of bubbles in the insulating filler can be suppressed, and the discharge caused by the bubbles can be suppressed. It becomes possible to do.

  As mentioned above, this invention can suppress the discharge by the bubble in the insulating filler in a soot pipe, and it becomes possible to reduce the possibility of the insulation fall of an air termination | terminus connection part.

It is sectional drawing of the air termination | terminus connection part of the electric power cable which is embodiment of invention. It is an expanded sectional view of the lower part of the air termination | terminus connection part of FIG. It is an expanded sectional view of the intermediate part of the air termination | terminus connection part of FIG. 3 is a further enlarged cross-sectional view of the upper tape winding layer. It is explanatory drawing which shows the butt winding of a tape. It is explanatory drawing which shows the gap winding of a tape. It is explanatory drawing which shows the winding of a tape. It is sectional drawing of the air termination | terminus connection part of the conventional power cable. It is explanatory drawing which shows the wrap winding of a tape.

One embodiment of the aerial terminal connection part of the power cable of the present invention will be described with reference to FIGS. 1 and 2.
As shown in the figure, the end portion of the stepped power cable 90 is also inserted from the lower end of the soot tube 20 in the air end connection portion 10 as in the example of FIG.
The soot tube 20 is made of an electrically insulating material, for example, porcelain. The lower part has an equal-diameter cylindrical shape, and the upper part has a cylindrical shape whose diameter decreases toward the upper end. Further, a hook-shaped umbrella portion 21 is formed on the outer peripheral surface of the rod tube 20 over almost the entire length. The umbrella part 21 is composed of small and medium-sized umbrella parts 21a and 21b that are alternately arranged in the vertical direction, and a large umbrella part 21c that is formed at a spacing less than these.
It should be noted that the soot tube 20 is not limited to porcelain but can be formed of other materials having high insulation properties. For example, the inner side of the tub tube 20 may be made of a fiber reinforced plastic (FRP) cylinder, and the entire outer peripheral surface including the umbrella portion 21 may be formed of highly insulating silicone or the like.

An upper metal fitting 22 that supports the conductor lead bar 11 connected to the tip of the cable conductor 91 is provided at the upper end portion of the soot tube 20, and a bottom plate 23 is provided at the lower end portion.
A cable receiving port 231 into which the power cable 90 is inserted is formed at the center of the bottom plate 23, and a mounting bracket 233 is provided on the lower surface thereof via a leg portion 232 extending downward. The mounting bracket 233 is connected to the gantry 25 via the support lever 24. Thereby, the soot pipe 20 is fixed on the mount frame 25 in a standing state.

  The cable receiving port 231 of the bottom plate 23 is equipped with a cylindrical cable protection fitting 26 having a mounting flange. A seal pipe 27 is disposed inside the cable protection metal fitting 26. The seal pipe 27 is attached from the outer semiconductive layer 93 to the shielding layer 94 of the power cable 90.

  As shown in FIG. 2, the lower end portion of the seal pipe 27 extends somewhat below the lower end portion of the cable protection fitting 26. And the lower tape winding layer 40 for oil stop is formed so that the lower end part of the cable protection metal fitting 26, the lower end part of the seal pipe 27, and the sheath 95 of the electric power cable 90 may be wrapped.

  The lower tape winding layer 40 includes a lead work portion 41 that joins the entire lower end portion of the cable protection fitting 26 and the outer peripheral surface of the seal pipe 27 in contact with the protrusion 271 fixed on the outer peripheral surface of the seal pipe 27. The epoxy putty 42 applied to the surface of the lead work part 41 and the flat net copper wire 43 covering the entire surface of the epoxy putty 42 are provided. The flat mesh copper wire 43 has an upper portion fixed to the outer peripheral surface of the cable protection metal fitting 26 by soldering, and a lower portion extending downward from the lower end portion of the seal pipe 27 to the outer peripheral surface of the shielding layer 94 of the power cable 90. It is fixed by soldering.

Further, in the lower tape winding layer 40, an epoxy-impregnated glass tape layer 44, a water shielding shrinkable tube 45, an insulating waterproof tape layer 46, and an adhesive vinyl tape layer 47 are provided so as to cover the entire surface of the flat mesh copper wire 43. They are stacked in order.
Epoxy tapes 48, 48 are wound around and fixed to the upper end portion and the lower end portion of the water shielding shrinkable tube 45.

  In addition, so-called end winding, in which an insulating tape made of an insulating synthetic resin is overlapped and wound at two places above and below the gap between the seal pipe 27 and the shielding layer 94 of the power cable 90 so that the side edges thereof are not displaced. Insulating tape layers 272 and 272 are formed (the upper insulating tape layer 272 is shown in FIG. 3).

The shielding layer 94 of the power cable 90 is formed of a smooth aluminum coating, and a single layer of wrapping is performed on the layer with a width of 1/2 using a polyvinyl chloride tape (not shown).
Further, as shown in FIG. 3, a tape layer 931 of a shield mesh tape in which fine metal wires are knitted in a mesh shape over the outer peripheral surface of the outer semiconductive layer 93 and the shielding layer 94, as shown in FIG. A tape layer 932 of a cloth tape covering this is formed. In the following description, the term “shielded mesh tape” refers to the above tape.

As shown in FIG. 3, the upper portion of the seal pipe 27 described above is reduced in diameter in the middle and extends to an intermediate portion of the external semiconductive layer 93, and at the upper end portion, the seal pipe 27 and the external semiconductive layer 93 are In order to fill the gap, a semiconductive tape layer 273 made of a semiconductive tape is wound around.
The semiconductive tape is a semiconductive tape by forming a semiconductive adhesive layer on one side of a butyl rubber based conductive vulcanized rubber sheet. In the following description, the term “semiconductive tape” refers to the above tape.
In addition, the semiconductivity formed on the outer peripheral surface of the outer semiconductive layer 93 and in the inner region of the seal pipe 27 is formed of one or two layers by wrapping a semiconductive tape with a width of 1/2. A tape layer may be formed.

Further, as shown in FIGS. 1 and 3, a tapered portion 933 is formed at the upper end portion of the outer semiconductive layer 93 of the power cable 90. A stress cone 50 is mounted at the boundary position between the external semiconductive layer 93 and the insulating layer 92. The stress cone 50 is molded in advance and includes a semiconductive rubber portion 51 and an insulating rubber portion 52.
In addition, an oil film 53 is formed in advance on the surface of the insulating rubber portion 52 by application of oil, thereby suppressing bubbles of the insulating oil 28 from adhering to the surface.

An upper tape winding layer 60 for shielding a cable is formed between the upper part of the seal pipe 27 and the lower part of the semiconductive rubber part 51 of the stress cone 50.
As shown in FIGS. 3 and 4, first, the upper tape winding layer 60 is insulated while gradually expanding its range in the vertical direction around the boundary position between the upper end of the seal pipe 27 and the outer semiconductive layer 93. A set of the tape layer 61 and the shrinkable tube 62 is formed in a triple.
Each of the insulating tape layers 61 is formed by wrapping each of the insulating tapes with a width of 1/2 and overlapping the six layers.
Each of the shrinkable tubes 62 is an insulating tube, and holds the inner insulating tape layer 61 due to its shrinkability.

Further, the upper tape winding layer 60 is formed with a valley filling portion 63 that fills the step between the semiconductive rubber portion 51 of the stress cone 50 and the external semiconductive layer 93 described above. The valley filling portion 63 is formed in a taper shape by wrapping a semiconductive tape with a width of 1/2 and overlapping the four layers.
The upper tape winding layer 60 is further provided with a semiconductive tape layer 64, a shield mesh tape layer 65, and a pressing tape layer 66. The semiconductive tape layer 64 is formed on the outer periphery of the outermost contraction tube 62 so as to be wider in the vertical direction than the contraction tube. The shield mesh tape layer 65 is provided as a metal shielding layer, and is more widely formed in the vertical direction on the outer periphery of the semiconductive tape layer 64. The pressing tape layer 66 is formed on the outer periphery of the shield mesh tape layer 65 more widely in the vertical direction.

As shown in FIG. 5, the semiconductive tape layer 64 is formed in one layer by wrapping a semiconductive tape, and the valley filling portion 63 is formed from the outer peripheral surface of the external semiconductive layer 93 of the power cable 90. The semi-conductive rubber part 51 is formed beyond.
As shown in FIG. 5, the butt winding refers to a state in which the side end portions of the tape are wound so as not to overlap each other.
The semiconductive tape of the semiconductive tape layer 64 is not limited to butt winding but may be gap winding.
As shown in FIG. 6, the gap winding refers to a state where the side ends of the tape are wound in a state where a certain gap A is generated. The gap of the semiconductive tape is preferably in the range of 0 or more (if it is 0, butt winding) is 5 mm or less.

As shown in FIG. 3 and FIG. 4, the shield mesh tape layer 65 is formed by winding a shield mesh tape as a shield tape one layer on top of another half the width, and at regular intervals in the vertical direction. The overlapped part is fixed by soldering. This shield mesh tape is in direct contact with the seal pipe below.
Further, the shield mesh tape starts to be wound upward from the position around the lower end of the valley filling portion 63 described above, and is folded around the lower portion of the semiconductive rubber portion 51 and wound downward. In the vicinity of the valley filling portion 63, there are two layers.

The pressing tape layer 66 is formed by winding a pressing tape. This pressing tape is a so-called raw Teflon tape in which a highly insulating Teflon (“Teflon” is a registered trademark) powder is used as a non-fired tape.
As shown in FIG. 7, the winding is performed by increasing the gap and performing the gap winding (see FIG. 6), and further overlapping the gap winding with the same gap with the spiral winding direction reversed. Is the method. In this case, the size of the gap is preferably wider than the tape width (for example, about 1 to 2 times the tape width). Although two layers are illustrated here, three or more layers can be used.
Note that the pressing tape of the pressing tape layer 66 may be butt winding or gap winding. The gap may be in the range of 0 to 5 mm as described above, but may be equal to or greater than the tape width (for example, about 1 to 2 times the tape width).

Also, in the case of the pressing tape layer 66, the winding of the pressing tape is started upward from the position around the lower end portion of the valley filling portion 63 described above, and is folded at a position above the upper end of the shield mesh tape layer 65. Since the winding is performed downward, only three layers are formed around the valley filling portion 63.
In the case of the pressing tape layer 66, butt winding (see FIG. 5) is performed from the winding start position to the upper end folding position.

As described above, in the aerial terminal connection portion 10 of the power cable 90, in the upper tape winding layer 60, the outermost presser tape layer 66 winds the presser tape, so there is no gap between the tapes. Even when the above occurs, the gap does not become a sealed state like a wrap winding, but is in an open state. For this reason, when manufacturing the termination | terminus connection part 10, the air in a clearance gap can be discharged | emitted rapidly. That is, it is possible to easily perform deaeration from the insulating oil. For this reason, it is possible to reduce bubbles generated in the insulating oil when the power cable 90 is energized, and it is possible to suppress a discharge due to the bubbles and a decrease in the insulating performance of the insulating oil due thereto.
Note that the pressing tape of the pressing tape layer 66 may be butt winding or gap winding. Even in this case, since the gap between the tapes is opened in the circumferential direction of the cable, it is possible to reduce the generation of bubbles and suppress the deterioration of the insulating performance of the insulating oil. However, when the press tape layer 66 is formed by stacking two or more layers of tape, the winding that is more advantageous for degassing than the butt winding or the gap winding is preferable.

Further, in the aerial terminal connection portion 10 of the power cable 90, the semiconductive tape layer 64 provided on the outer periphery of the outermost shrinkable tube 62 also has the semiconductive tape butt-wrapped. Similarly, the gap between the tapes is opened, and it is possible to reduce the generation of bubbles when the power cable is operated. For this reason, it becomes possible to suppress the discharge by a bubble and the fall of the insulation performance of insulating oil by this.
Also in this case, the semiconductive tape of the semiconductive tape layer 64 can be a gap winding. Even in that case, it is possible to avoid the generation of a gap between the tapes, reduce the generation of bubbles, and suppress the deterioration of the insulating performance of the insulating oil.

  The shield mesh tape layer 65 is wrapped, but this is a structure in which the shield mesh tape has a gap in which fine metal wires are knitted into a mesh shape, and air bubbles are sealed between the tapes. This is because there is almost no need for butt winding or gap winding.

In addition, the structure of each part of the in-air termination | terminus connection part 10 of the electric power cable mentioned above is an example, and is not limited to this.
For example, the insulating oil sealed in the soot tube 20 may be various electrical insulating oils defined in Japanese Industrial Standards JIS C 2320. Also, not only insulating oil but also other insulating fillers that can be sealed, such as silicone gel, a mixture of silicone oil and silicone rubber, a mixture of dimethyl silicone oil and silicone gel, a mixture of silicone oil and silicone rubber and silicone gel, etc. However, an insulating material may be used.

  Moreover, although the stress cone was illustrated as an electric field relaxation layer formed in the external semiconductive layer of an electric power cable, you may utilize not only this but a capacitor | condenser cone, for example.

10 In-air terminal connection 20 碍 pipe 28 Insulating oil (insulating filler)
50 Stress cone 51 Semiconductive rubber part (electric field relaxation layer)
40 Lower tape winding layer 60 Upper tape winding layer 61 Insulating tape layer 62 Shrinkable tube 64 Semiconductive tape layer 65 Shield mesh tape layer (metal shielding layer)
66 Holding tape layer 90 Power cable 91 Cable conductor 92 Insulating layer 93 External semiconductive layer 94 Shielding layer 95 Sheath

Claims (3)

A soot tube that houses the end of the power cable and is filled with an insulating filler;
A metal shielding layer formed by winding a shielding tape around the outer semiconductive layer exposed at the terminal end of the power cable;
A pressing tape layer formed by winding a pressing tape from above the metal shielding layer,
The pressing tape is a butt winding in which the adjacent tape and the side edges of the tape are closely in contact with each other around the winding, or a gap winding in which a gap is generated between the adjacent tape and the side edges of the tape in every winding. An aerial termination connection part of a power cable, characterized by being wound.   The in-air terminal connection portion of a power cable according to claim 1, wherein the pressing tape is wound with a winding that is sequentially stacked so that a spiral direction by the gap winding is opposite to that of the lower layer. . In the lower layer than the pressing tape layer, comprising a semiconductive tape layer formed by winding a semiconductive tape,
The air cable terminal connection part according to claim 1 or 2, wherein the semiconductive tape is wound around the power cable by the butt winding or the gap winding.

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