JP4028002B2 - Sheath insulated prefabricated connection for power cable - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to an improvement in a sheath insulation type prefabricated connection part of a power cable.
[0002]
[Prior art]
FIG. 4 shows a general configuration of the sheath insulation type prefabricated connection portion of the power cable.
This prefabricated connecting portion is composed of a conductor connecting portion 4 formed by connecting two cable conductors with a sleeve in the center, and an inner shielding electrode 12 surrounding the conductor connecting portion 4, and an epoxy resin molded body fixed to the outer periphery of the electrode on the outside thereof. And a prefabricated connection body having a pre-molded insulator 2 called a stress cone that is pushed between the insulating cylinder 3 and the cable insulator 1. The pre-molded insulator 2 is provided with an insulating pipe 9 and an insulating pipe pressing fitting 10 that are pressed against the insulating cylinder 3.
[0003]
Further, a metal sheath shielding part is provided on the outer periphery of the prefabricated connecting part main body. The shielding part is connected to the metal sheath of the cable, and this connection part is composed of copper tube 5, cylindrical sheath insulation adapter 6, metal flange 7, protective copper tube 8, metal flange 7, and copper tube 5 from the left. Has been. Although it is desirable that the shielding portion exist over the entire length, if it is too long, the induced voltage becomes too high, so that the connection portion is insulated and twisted. For this insulation, the sheath insulation adapter 6 made of epoxy is inserted to cut the metal sheath, but the end of the insulation cylinder 3 is selected as the position to be selected. The reason for this is that the stripping allowance of the cable insulator 1 on one side is lengthened due to assembly, so that there is a gap, the most important part is escaped from the surface of electrical stress, and the insulation that pushes in the premold insulator 2 This is because a flange is necessary to take the fulcrum of the pipe 9. In general, this position is selected to create a compact prefabricated connection. An enlarged view of the portion A is shown in FIG.
[0004]
As is apparent from this figure, the insulating pipe 9 is in the middle here. Since this insulating pipe 9 strongly presses the pre-molded insulator 2, FRP having higher strength than epoxy is used.
In this figure, the sheath insulation adapter 6 is composed of a left flange 6a, an adapter body 6b, and an embedded flange 6c. The insulating pipe push fitting 10, the lower copper tube 5, and the left flange 6a are coupled to the left metal sheath, and the metal flange 7 and the protective copper tube 8 are coupled to the right metal sheath.
[0005]
The performance of the conventional sheath insulation type connection portion is required by the sheath insulation impulse voltage performance, and the sheath insulation impulse voltage has increased as the withstand voltage of the connection portion has increased. When the sheath insulation impulse voltage was low, the destruction route always occurred on the sheath insulation adapter 6 side, and the phenomenon that the left flange 6a flashed with the metal flange 7 and ran on the surface of the insulation pipe 9 separated inward did not occur. In order to increase the sheath insulation impulse voltage, the insulation pipe 9 can be made longer by increasing the length of the adapter body 6b.
[0006]
[Problems to be solved by the invention]
However, when the sheath insulation impulse voltage exceeds 120 kV and the adapter body 6b is lengthened, the sheath insulation adapter 6 side can withstand the sheath insulation impulse voltage, but the surface flashing phenomenon that the leakage current runs on the surface of the insulation pipe 9. Occurred. In other words, a flashing occurred on the flange of the insulating pipe pressing metal 10 through the surface of the insulating pipe 9 from the metal flange 7. Therefore, it is necessary to remove this surface flash. First, the length of the insulating pipe was increased, but no effect was obtained within the design margin.
[0007]
[Means for Solving the Problems]
The present invention has been proposed in order to solve the above-described problems, and includes a conductor connecting portion, an internal shielding electrode surrounding the conductor connecting portion, an insulating cylinder fixed to the outer periphery of the electrode, and the insulating cylinder and the cable insulator. A pre-molded insulator pushed in between, a prefabricated connection body provided with an insulating pipe for pushing and fastening the pre-molded insulator, a copper pipe connected to a metal sheath of a cable, a protective copper pipe on an insulating cylinder, the copper in sheath insulated prefabricated connections become more power cables and shielding part formed on the outer periphery of the Sea scan is composed of insulated adapter prefabricated connecting body for insulating the protective copper tube with the tube, said insulating sheath insulation adapter side to inhibit flashover along the outer peripheral surface of the pipe on the outer peripheral surface axial direction of the sheath impulse voltage, ring-shaped protrusions over the entire circumference to be one or a plurality of barrier Characterized by providing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail based on the embodiment shown in FIGS. This connecting portion includes a conductor connecting portion 4, an internal shielding electrode 12 surrounding the conductor connecting portion 4, an insulating tube 3 fixed to the outer periphery of the electrode 12, and a pre-pressed portion between the insulating tube 3 and the cable insulator 1. A mold insulator 2, a prefabricated connector main body having an insulating pipe 9 for pressing and fastening the premold insulator 2, a copper pipe 5 connected to a metal sheath of a cable, a protective copper pipe 8 on the insulating cylinder 3, The sheath insulation adapter 6 side of the sheath insulation type prefab connection portion of the power cable, which is composed of a sheath insulation adapter 6 that insulates the copper tube 5 and the protective copper tube 8 and is formed on the outer periphery of the prefab connection portion main body. In order to eliminate the flash along the outer peripheral surface axial direction due to the sheath impulse voltage on the outer peripheral surface of the insulating pipe 9, two ring-shaped protrusions extending over the entire circumference along the pipe axial direction. 11, configured by providing substantially 3 equally positioned flanges fitting 10 press both sides of the metal flange 7 insulated pipe. By providing two protrusions 11 over the entire circumference, the protrusions became barriers, and a space of 300 mm outer diameter 220 mm inner diameter length 250 mm could withstand an impulse voltage of 120 kV.
[0009]
Four types of projection shapes shown in FIGS. 3A to 3D were compared. Judging from the impulse resistance characteristics, the shape (A) is the same as the shape (B), and there is no superiority between the shape (C) and the shape (D) where processing is performed, and any shape may be used. .
[0010]
【The invention's effect】
As described above, the sheath insulation type prefabricated connection portion of the power cable according to the present invention obstructs the flash along the axial direction by the sheath impulse voltage on the outer periphery of the insulation pipe that presses and fastens the premold insulator, and thus one or more Since the ring-shaped protrusions are provided over the entire circumference as a barrier, the impulse performance between the connecting portion sheaths can be improved.
[Brief description of the drawings]
FIG. 1 is a front half-sectional view of a sheath-insulated prefabricated connection according to the present invention.
FIG. 2 is a cross-sectional view of the vicinity of an insulation pipe of a sheath insulation type prefab connection portion according to the present invention.
FIG. 3 is an explanatory diagram showing various shapes of protrusions formed on the outer surface of an insulating pipe.
FIG. 4 is a front half-sectional view of a conventional sheath-insulated prefabricated connection section.
FIG. 5 is a cross-sectional view of the vicinity of a conventional insulating pipe.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cable insulator 2 ... Premold insulator 3 ... Insulation cylinder 4 ... Conductor connection part 5 ... Copper pipe 6 ... Sheath insulation adapter 6a ... Left flange 6b ... Adapter Body 6c .. Embedded flange 7 ... Metal flange 8 ... Protective copper tube 9 ... Insulating pipe 10 ... Insulating pipe metal fitting 11 ... Projection 12 ... Internal shielding electrode

Claims (1)

Conductor connection part, internal shielding electrode surrounding the conductor connection part, insulating cylinder fixed to the outer periphery of the electrode, pre-molded insulator pushed between the insulating cylinder and the cable insulator, and the pre-molded insulator is pushed in and fastened a prefabricated connecting part body with an insulating pipes, copper pipes are connected to the metal sheath of the cable, the protective copper tube on the insulating tube, the protective copper tube and the copper tube is constructed from Sea scan insulation adapter to insulate In the sheath insulation type prefab connection part of the power cable consisting of the shielding part formed on the outer periphery of the prefabricated connection part body, a flash along the outer peripheral surface axial direction by the sheath impulse voltage on the outer peripheral surface of the insulation pipe on the sheath insulation adapter side to inhibit, one or a plurality of sheath insulated flop of power cables, characterized in that a ring-shaped projection over the entire circumference as a barrier Hub connection.

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