JPH0591639A - Detecting method for malfunction of cable connector - Google Patents

Abstract

PURPOSE:To provide a method of early detecting such a malfunction of a cable connector as an improper construction of the connector. CONSTITUTION:Edge cut parts 14, 14 are formed at a metal body tube 10 for constituting a cable connector. One of the parts 14, 14 is short-circuited by a lead 15, and a clamp CT16 is mounted at the lead 15. If a malfunction such as an improper construction exists at the connector, a partial discharge occurs at the malfunctioned part, and a partial discharge pulse flows to the lead 15. The pulse is detected by the clamp CT16, sent to a measuring instrument 17 to measure the pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting an abnormality in a cable connecting portion, which is capable of early detecting a construction failure or the like, which is a main cause of dielectric breakdown of a cable connecting portion, particularly a prefabricated type connecting portion. .

[0002]

2. Description of the Related Art In recent years, a prefabricated type connecting portion for assembling unitized parts on site to complete the connecting portion has been put into practical use as an intermediate connecting portion for a CV cable. Since no process is required, there are advantages that the construction time can be greatly shortened and construction management is easy compared with the extrusion mold type connection part.

[0003]

By the way, in such a prefabricated type connecting portion, if there is a construction defect or a component such as an epoxy unit or a rubber mold stress cone is damaged during the construction, it will be in an operating state. When this happens, a partial discharge will occur, which may eventually lead to a dielectric breakdown accident. Therefore, it is important to detect the partial discharge occurring at the connection part early and prevent the dielectric breakdown accident before the dielectric breakdown accident, in order to improve the reliability of the cable line. Therefore, the present invention has been devised in consideration of the above circumstances, and it is possible to detect an abnormality in a cable connecting portion such as a prefabricated type connecting portion at an early stage, and thus to prevent an accidental breakdown of the cable connecting portion. It is an object of the present invention to provide a method for detecting an abnormality in a cable connecting portion that can be prevented.

[0004]

In order to solve the above-mentioned problems, the present invention is a method for detecting an abnormality in a cable connecting portion for connecting cables having shielding conductors, wherein the connecting portion is formed and the shielding is performed. An insulating portion is provided on the outer conductor connected to the conductor to electrically separate the outer conductor in the longitudinal direction thereof, and a short circuit path is provided between the outer conductors electrically separated by the insulating portion, and the short circuit is formed. An abnormality of the connecting portion is detected based on the partial discharge pulse flowing in the road.

[0005]

According to the present invention, when partial discharge occurs due to defective construction of the cable connection portion or damage to parts, a partial discharge pulse flows in the short-circuit path. Therefore, by detecting this partial discharge pulse, the cable connection can be performed. It is possible to detect an abnormality in a part.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a prefabricated type insulation connection portion, and FIG. 2 is an equivalent circuit diagram of the insulation connection portion. First
As shown in the figure, at the end of the CV cable 1, the outer semiconductive layer (not shown), the insulator 2, and the inner semiconductive layer (not shown) are stepped off to expose the conductor 3. The tip ends of the conductors 3, 3 are inserted into the conductor connecting pipe 5, and the conductor connecting pipe 5 is compressed to connect the conductors 3, 3. 1 and 2, reference numeral 4 indicates a shield conductor of the CV cable 1.

A shield electrode 7 embedded in an epoxy unit 6 is provided on the outer periphery of the conductor connecting tube 5, and a rubber mold stress cone (hereinafter referred to as a stress cone) is provided at the end of the CV cable 1. ) 8 is inserted. The inclined portion 8a of the stress cone 8 is fitted to the inclined portion 6a of the epoxy unit 6, and a pressing force is applied to the stress cone 8 by spring units (not shown) provided on both end sides of the epoxy unit 6. By this pressing force, the inclined portion 8a of the stress cone 8 is in close contact with the inclined portion 6a of the epoxy unit 6 to maintain a predetermined surface pressure.

On the other hand, the metal barrel 10 covering the epoxy unit 6 and the like is composed of a main body portion 11 and two end portions 12 and 12. The main body portion 11 and the end portions 12 and 12 are made of an insulating cylinder 13. , 13 are fixed by insulating bolts (not shown) to form edge cut portions 14, 14.
The body portion 11 and the end portion 12 are electrically separated from each other by the lengths 4 and 14. The two ends 12, 12 of the metal body tube 10 are connected to the shield conductors 4, 4 of the CV cables 1, 1.

In one of the two edge cuts 14, 14 (the right edge cut in FIG. 1), the main body 11 and the end 12 which are electrically separated from each other lead. Line 1
Connected with 5. A clamp CT 16 for detecting a partial discharge pulse is attached to the lead wire 15, and the clamp CT 16 is connected to the measuring device 17. Reference numeral 18 indicates a connection terminal for connecting the lead wire 15.

In the above construction, there is a construction failure such as a failure of fitting of the stress cone 8 in the insulating connection portion or non-uniform pressure of the stress cone 8, or the epoxy unit 6 or the stress cone 8 is not attached during the construction. If the parts are damaged, partial discharge will occur at the defective parts or damaged parts after the operation of the cable line is started. Now, assuming that this partial discharge occurs at point X in FIG. 2, the partial discharge pulse is
The lead wire 15 flows in the direction of the arrow in the figure, and this partial discharge pulse is detected by the clamp CT 16 and sent to the measuring device 17. Therefore, according to the present embodiment, the measuring device 1
By measuring the partial discharge pulse at 7, it is possible to detect the construction failure of the insulating connection portion and the damage to the parts at an early stage, and thus to prevent the accidental breakdown of the cable connection portion.

Next, an embodiment in which the present invention is applied to a three-phase single-phase line will be described with reference to FIG. FIG. 3 is an equivalent circuit diagram of an insulation connection portion of a cable line laid in three phases. In FIG. 3, the same members as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG.
The three CV cables 1 form a three-phase cable line of A phase, B phase, and C phase, and the shield conductor 4 of the insulating connection portion 20 is connected to the shield conductor 4 of another phase by the cross bond wire 21. Has been done. Now, Y of the A-phase cable line
If a partial discharge occurs at a point, the partial discharge pulse is
Although it flows to the other phase through the cross bond line 21, the phase in which the partial discharge occurs can be specified by the magnitude of the pulse. That is, the partial discharge pulse is shunted in the directions of the arrow a and the arrow b as shown in the figure, but each partial discharge pulse detected by the clamp CT16 of the B phase and the clamp CT16 of the C phase is the A phase. Clamp CT16
Since it is smaller than the partial discharge pulse detected in step A, it can be specified that the phase in which the partial discharge occurs is phase A, and it can be detected that the insulation connection portion 20 of phase A has a construction failure or damage to parts. .

In the above embodiment, the abnormality detection of the prefabricated type insulation connection portion was illustrated, but the present invention can be applied not only to the insulation connection portion but also to the abnormality detection of the prefabricated type normal connection portion. In this case, the left edge cutting portion 14 in FIG. 1 may be omitted. That is, the insulating cylinder 13 on the left side in FIG. 1 may be omitted, or the body portion 11 and the end portion 12 may be connected by a lead wire. The present invention can of course be applied to the detection of an abnormality in a connection portion other than the prefabricated type.

[0013]

As described above, according to the present invention,
It is possible to detect an abnormality in the cable connection portion such as the prefabricated connection portion at an early stage, and thereby prevent an accidental breakdown of the cable connection portion.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a prefabricated insulating connection portion.

FIG. 2 is an equivalent circuit diagram of the same insulation connection part.

FIG. 3 is an equivalent circuit diagram of an insulation connection portion of a cable line provided with three phases.

[Explanation of symbols]

 1 ………… CV cable 3 ………… conductor 4 ………… shielding conductor 6 ………… epoxy unit 8 ………… stress cone 10 ………… metal shell 11 ………… main body 12 …… … End 13 ………… Insulation cylinder 14 ………… Edge cutout 15 ………… Lead wire 16 ………… Clamp CT 17 ………… Measuring instrument

Claims (2)

[Claims] 1. A method for detecting abnormality in a cable connecting portion for connecting cables having shield conductors to each other, wherein an insulating portion is provided on an outer conductor which constitutes the connecting portion and is connected to the shield conductor. A conductor is electrically separated in its length direction, a short-circuit path is provided between the outer conductors electrically separated by the insulating part, and an abnormality of the connection part is detected based on a partial discharge pulse flowing in the short-circuit path. A method for detecting an abnormality in a cable connecting portion, which is characterized by detecting. 2. The method for detecting an abnormality in a cable connecting portion according to claim 1, wherein the cable connecting portion is a prefabricated type connecting portion.