JPH0660925B2 - Inspection method of prefabricated type connection part for CV cable - Google Patents

Description

Description: [Industrial field of use] The present invention relates to a method for inspecting a prefabricated connector for a CV cable.

[Prior Art] The connecting portion for a CV cable of 154 kV to 275 kV uses a tape winding molding method in which polyethylene tape containing a cross-linking agent is laminated and wound to perform cross-linking molding, or an extruder is used to set a foreign substance level to approximately a cable insulator. An extrusion molding method in which polyethylene containing a cross-linking agent is extruded and cross-linked has been applied to an actual line. These tape winding molding methods or extrusion molding methods require a heat-crosslinking step to assemble the connection parts,
There was a problem that the assembly time would be long.

Therefore, a prefabricated type connecting portion for assembling and connecting unitized parts has been proposed and is actually used.

The configuration of this prefabricated type connecting portion will be described below with reference to the drawings. FIG. 3 is a sectional view showing only the upper half of the structure of the prefabricated type connecting portion. CV cable to connect 1,
The end of 1'is stripped off to expose the cable conductors 1a, 1a, which are butted and covered with a conductor sleeve 2 for compression and connection. A cylindrical epoxy unit 4 having a taper surface on the inner surface formed by embedding a metal high-voltage electrode 3 having a T-shaped cross section, which has been inserted through a cable in advance at this connection portion.
The conductive sleeve 2 and the high-voltage electrode 3 are connected by a connecting ring 11, and an annular stopper 10, between the inner peripheral surface of the epoxy unit 4 and the insulator of the cables 1, 1 '.
Insert 10 'and fix. This stopper 10,1
0'is for preventing the tip of the rubber mold stress cone from entering between the epoxy unit 4 and the insulators of the cables 1, 1 '. Next, a cylindrical rubber mold stress cone 5, which has holes for inserting the cables 1 and 1'in the center from the left and right and has a tapered surface at the tip,
5'is fitted so as to abut the tapered surface of the epoxy unit 4. This rubber mold stress cone 5,5 '
On the back side of the rubber mold stress cone conductive layer 6,
6'is integrally formed and provided. Then, the connection case 9 is attached on the epoxy unit 4, and the spring units 8 provided at the left and right ends of the case 9 are
The pressing metal fittings 7 and 7'of 8'are assembled by pressing the conductive layer portion on the back surface of the rubber mold stress cones 5 and 5 '.

In this way, this prefabricated type connecting portion is a combination of an epoxy unit made of an epoxy resin for electrical insulation, a rubber mold stress cone formed of ethylene-propylene rubber (EPR) and silicon rubber, and is pressed by a spring unit for compression. The electrical insulation between the epoxy unit and the CV cable insulator is ensured.

[Problems to be Solved by the Invention] Although it has been attempted to inspect the electrical insulation of each component forming such a prefabricated type connection portion to ensure the electrical insulation of the connection portion, the epoxy is used. Until now, there has been no method of inspecting the state in which the unit and the rubber mold stress cone are combined by a corona test or the like.

As described above, the problem that the partial discharge test (commercial frequency partial discharge test), which is an electrical inspection method, cannot be performed in a state in which the components of the prefabricated type CV cable connection part are assembled in the actual use state is as follows. The prefabricated connection is large and may require dedicated test equipment, but there was no method to improve the detection level of the partial discharge test, and because it imposes high voltage, it needs to be terminated. This is probably because there was no structure or structure for the discharge test.

The present invention has been made in view of such a point, and C
An object of the present invention is to provide an inspection method capable of performing a partial discharge test in a state in which each part of a prefabricated type connection portion of a V cable is actually assembled.

[Means for Solving the Problems] In the present invention, as a CV cable connection portion, a prefabricated type connection is formed by combining an epoxy unit in which a high-voltage shield electrode is embedded with a rubber mold stress cone and pressing and compressing this with a spring unit. In the inspection of the assembled state of the epoxy unit and the rubber mold stress cone, the two epoxy simulated cables with the electric field shield structure at one end and the specified rubber mold stress cone at the other end are connected to the epoxy unit. Attach it and assemble it into an actual assembled state with a spring unit to make a test sample.Place this assembled test sample in the case inside the gas insulation test equipment, fill it with insulating gas at a specified pressure, and apply power from the high-voltage power supply. The test sample was detected by the partial discharge detector. A method of inspecting a prefabricated connection portion CV cable characterized and.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a method for inspecting a prefabricated type CV cable connecting portion according to the present invention. The same members as those shown in FIG. That is, the epoxy unit 4 that constitutes the prefabricated type connection portion is a cylindrical member having tapered surfaces 4a formed on both sides from both sides toward the hole 4b for inserting the cable in the center, and the cross section is T-shaped inside the center portion. The annular metal high-voltage electrode 3 having the above-mentioned shape is integrally formed by molding. Actually, the ends of the connection portion of the CV cable are inserted into the epoxy unit 4 from both sides, but in this inspection method, the epoxy simulated cables 20, 20 'are inserted. That is, the simulated cables 20 and 20 'are formed by sticking epoxy resin around the central metal pipe or the conductive plastic pipes 21 and 21' to form a rod shape. Shields 20a and 20a 'are formed respectively. The metal pipes 21 and 21 'are attached to the tips.
Recessed tip fittings 22 and 22 'that are screwed together are attached, and threaded portions 22a and 22a' are also formed on the concave inner surfaces of the tip fittings 22 and 22 '. This tip fitting 2
2, 22 'are annular connecting rings 23, 23' having a flange portion that abuts the protruding portion 3a of the metallic high-voltage electrode 3 of the epoxy unit 4, respectively.
The threaded portions 22a and 22a 'provided on the concave inner surface of 2'are respectively screwed and attached. Connection ring 2 on the left
A screw portion 23b is formed on the inner peripheral surface of the inner surface of 3 for fixing the left simulated cable 20, and the screw portion 25a at the tip of the copper conductor fixing metal fitting 25 is screwed to this screw portion 23b. Is formed in. A flange portion 25b and a screw portion 25c for attaching the nut 26 are formed on the right end side of the conductor fixing bracket 25.

Next, the simulated cables 20 and 2 formed in this way
A case of assembling a test sample of a connection portion to be inspected using 0'is described. Left and right simulated cables 20, 20 '
The tip fittings 22 and 22 'and the connecting rings 23 and 23' are attached to the tip ends of the respective parts by screws. And
The epoxy units 4 are inserted from the left and right sides so that they are in contact with each other at the central portions. At this time, the connection ring 23 'of the right simulated cable 20' is provided with a cutout portion that engages with the protruding portion 3a of the high-voltage electrode 3 of the epoxy unit 4, and the connection rings 23, 23 'are accurately formed. The contact is made at the center. Next, these connecting rings 23, 23 '
Then, the annular stoppers 10 and 10 'are inserted into the annular space formed by the inner surface 4b of the epoxy unit 4 and the outer peripheries of the left and right simulated cables 20 and 20' so as to abut the connection rings 23 and 23 '. These stoppers 10,1
0'is for preventing the tip of the rubber mold stress cone from entering. Right simulated cable 2
The conductor fixing metal fitting 25 is inserted through the center of 0 ', and the screw portion 25a at the tip is screwed and fixed to the screw portion 23b provided on the inner periphery of the connection ring 23 attached to the tip of the left simulated cable 20. Then, the nut 26 is fitted and screwed into the threaded portion 25c provided at the right end of the conductor fixing metal fitting 25, so that the flange portion 25b has the right side of the simulated cable 20 '.
The simulated cables 20, 20 'are fixed by abutting on the right end of the.

Next, the cone-shaped rubber mold stress cones 5 and 5'are respectively inserted from the left and right, and the back surfaces of the respective spring units 8 and 8 are provided at the ends of the connection case 9 attached to the outer periphery of the epoxy unit 4. The metal fitting stress cones 5 and 5'are made to contact with the pressing metal fittings 7 and 7'of the ′ and pressed by the force of the spring, and the taper surfaces 4a and 4a ′ of the epoxy unit 4 cause the epoxy unit 4 to move.
Then, the test sample of the connection portion is assembled by making close contact with the outer periphery of the simulated cables 20, 20 '.

The connection portion of the test sample thus formed is placed on the carriage 30 and carried into the carriage 31 constituting the partial discharge measuring apparatus as shown in FIG. This partial discharge test apparatus comprises a trolley 31 provided with a high-voltage power supply 33 and a case 32, and the left side of the high-voltage power supply 33 is a conductor fixing metal fitting of a simulated cable 20 'on the right side of a connecting portion which is a test sample. A terminal portion 33a that is directly connected to the end portion of 25 is provided and connected. Also,
The measurement lead wire 33 is connected to the connection connector 34 of the case 32 from a predetermined position of the epoxy unit 4, and the connector 34 is connected to the partial discharge detection device 35. Dolly 31
To the right and place the case 32 on the wall of the high voltage power supply 33.
The opening is made to contact so as to be hermetically sealed, and an insulating gas such as SF6 is sealed and filled to a predetermined pressure from a supply port (not shown) provided in the case 32. Then, the high voltage power supply 33 is operated, a predetermined high voltage is applied to the connection portion of the test sample, and the partial discharge level of the epoxy unit 4 is detected by the partial discharge detector 35.

In the above example, the partial discharge measuring device has been described as a device that measures one connecting portion, which is a test sample, but it may be configured so that a plurality of measuring devices are arranged in parallel.

[Effects of the Invention] As described above, according to the method for inspecting a prefabricated type connection portion for a CV cable of the present invention, since the epoxy unit and the rubber mold stress cone can be assembled in a state where they are actually used, a partial discharge test can be performed. A prefabricated type connection part having improved inspection performance and high reliability can be provided.

Easy to assemble for testing and easy to handle.

One or more prefabricated connections can be tested simultaneously.

It has excellent effects such as.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a CV cable prefabricated type connection portion inspection apparatus according to an embodiment of the present invention, FIG. 2 is a side view of a partial discharge measurement apparatus, and FIG. 3 is a prefabricated type connection apparatus. It is sectional drawing which shows only the upper half part which shows the structure of a part. 4 ... Epoxy unit 5, 5 '... Rubber mold stress cone 7, 7' ... Push metal fitting 8,8 '... Spring unit 9 ... Connection part case 10, 10' ... Stopper 20, 20 '... Epoxy simulated cable 20a, 20a' ... Electric field shielding part 30,31 ... Truck 32 ... Case 33 ... High voltage power supply 35 ... Partial discharge detector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Tanno 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Electric Cable Research Institute, Hitachi Cable Ltd. (72) Inventor Hideo Sato 5-chome, Hidaka-cho, Hitachi-shi, Ibaraki No. 1 in the Electric Wire Research Laboratory, Hitachi Cable Ltd.

Claims (2)

[Claims] 1. An epoxy unit and a rubber mold stress cone for a prefabricated type connecting portion, which is constructed by combining a rubber mold stress cone with an epoxy unit in which a high voltage shield electrode is embedded and compressing this with a spring unit as a CV cable connecting portion. In the inspection of the assembled state of, the two epoxy simulated cables, one end of which has an electric field shielding structure and the other end of which a predetermined rubber mold stress cone is arranged, are attached to the epoxy unit, and the actual assembled state by the spring unit. Assembled into a test sample, place the assembled test sample in a case inside the gas insulation tester, fill the chamber with insulating gas at a specified pressure, and apply a voltage from a high-voltage power source to detect partial discharge of the test sample. For CV cable, characterized by the fact that Inspection method of Rehabu type connection. 2. The method for inspecting a prefabricated type connection portion for a CV cable according to claim 1, wherein the gas insulation test apparatus has a structure in which a case is integrally mounted on a carriage.