JPH06186278A - Apparatus and method for diagnosis of deterioration of prefabricated joint - Google Patents

Abstract

PURPOSE:To accurately diagnose the deterioration of an insulator installed at a prefabricated joint of the cables. CONSTITUTION:In a prefabricated joint of insulating cables, a recessed part 2A is formed in a shielding conductor 2 in contact with insulators 5, 6, 7, and one end of a detection terminal 4 to be used as an electrode of a capacitor is attached to the recessed part 2A integrally with a resin 3. Then, the detection terminal 4 is connected to an oscilloscope. When an abnormal part is caused in the insulators 5, 6, 7, the generation of an abnormality such as separation, void and the like of the insulators can be confirmed by a partial discharge signal which is output from the detection terminal 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prefabricated joint which is capable of diagnosing the presence or absence of physical abnormality such as deterioration and voids and cracks at the interface between an insulator and a conductor provided in a prefabricated joint of an insulated cable. The present invention relates to a deterioration diagnosis device and method.

[0002]

2. Description of the Related Art Regarding transmission of high-voltage power, how to maintain insulation performance and ensure safety and reliability has become an important issue. For example, in the insulator provided in the prefabricated joint of the insulated cable, in addition to the initial assembly failure,
Degradation such as peeling may occur at the interface with the conductor due to long-term energization or the like, or deterioration may progress due to microscopic defects or the like inherent in the insulator. If this is left as it is, there is a possibility that the insulator may be damaged, so that it is necessary to inspect the state of the insulator such as deterioration at any time. Therefore, a partial discharge measurement method has been developed as this inspection method. That is, in this partial discharge measurement method, for example, as shown in FIG. 4, the observation target 100 is not grounded and a signal for inspection is directly input to the detection impedance 101, and as shown in FIG. It is known that a coupling capacitor 102 is provided in parallel with the above, and a test signal is input to the detection impedance 103 from this low voltage side conductor. However, in these methods, for example, it is necessary to provide the above circuit for each prefabricated joint of the cable, which is practically impossible. Therefore, for example, as shown in FIG. 6, in each prefabricated joint of the cable, the metal foil electrode 105 is provided and the vinyl anticorrosion layer 104 is used as a dielectric to form the abnormality detecting capacitor, and the vicinity of the connection portion of the cable shown in FIG. Forming a high frequency filter 106 at the cable end of
An EDI sensor has been proposed.

[0003]

However, in the type using the metal foil electrode, it is difficult to carry out an accurate inspection due to variations in the mounting method.
Since the sensor using the EDI sensor has inherent variations depending on the element used, there is a disadvantage that it is necessary to calibrate each sensor every time to convert it into a charge amount. Therefore, in view of the above-mentioned conventional drawbacks, the present invention provides a prefabricated joint deterioration diagnosing apparatus and method capable of accurately diagnosing an abnormality such as deterioration of an insulator provided in a prefabricated joint of each cable. It is intended.

[0004]

That is, the present invention is a deterioration diagnosis device for a prefabricated joint for detecting the presence or absence of an abnormal portion such as a deterioration or a void in an insulator provided in a prefabricated joint of an insulated cable, A detection terminal having one end embedded integrally with resin in a recess formed in the shield conductor in contact with the insulator is provided, and a capacitor is formed between the shield conductor and the detection terminal. Further, the present invention is a method of diagnosing deterioration of a prefabricated joint for detecting the presence or absence of abnormal portions such as deterioration and voids in an insulator provided in a prefabricated joint of an insulated cable, which is formed on a shield conductor in contact with the insulator. The presence or absence of the abnormal portion of the insulator is diagnosed by the partial discharge signal output from the detection terminal in which one end is embedded in the concave portion integrally with the resin.

[0005]

In the deterioration diagnosing device of the present invention, in order to form a detection capacitor in the shield conductor in contact with the insulator at each connection portion of the electric wire cable, resin is injected into the recess formed in the shield conductor. One end of the detection terminal that becomes an electrode is molded integrally.For example, by connecting the oscilloscope and this detection terminal, when there is an abnormality such as peeling or void in the insulator, peel it from the partial discharge signal. It is possible to detect anomalies such as voids and voids.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a deterioration diagnosis device 8 for a prefabricated joint according to the present invention. This deterioration diagnosis device 8 is an insulator (epoxy unit 5, rubber stress relief cone 6 and cable insulator) in a prefabricated joint of a high voltage cable 1. 7), a shield conductor 2 provided in contact with the shield conductor 2, a recess 2A formed in a part of the shield conductor 2 and filled with a resin (for example, an epoxy resin) 3 forming a dielectric of a capacitor, and a recess 2A provided in the recess 2A. It is composed of the detection terminal 4, and by observing the signal waveform output from the detection terminal 4, deterioration or voids in each insulator of the epoxy unit 5, the rubber stress relief cone 6 and the cable insulator 7 The presence or absence of abnormality is detected. In addition, this deterioration diagnosis device 8
Are provided at both connecting portions of the cables 9A and 9B as shown in FIG. The detection terminal 4 has its one end placed in the recess 2A formed in a part of the shield conductor 2 and
The resin 3 is placed inside and molded integrally with the resin 3.
It is formed so as to form a capacitor having a capacitance of about 0 PF.

Next, a deterioration diagnosis method for detecting an abnormality such as deterioration of an insulator by using the deterioration diagnosis device 8 according to this embodiment will be described. The deterioration diagnosis method includes a deterioration diagnosis device 8 and
A wideband amplifier 10 for amplifying the output of the diagnostic device 8 given via the coaxial cable 9, an oscilloscope 11 for observing the output of the amplifier 10, and an A / D converter for converting the output of the amplifier 10 into a digital signal. 12 and A /
A device including a computer 13 that performs a predetermined process on the digital signal converted by the D converter 12 is used. The output of the deterioration diagnostic device 8 is input to the amplifier 10 via the coaxial cable 9, but the amplifier 1
If an ultra-small one is used as 0, this deterioration diagnosis device 8
It is also possible to attach it to a part of. The oscilloscope 11 inputs the signal amplified by the amplifier 10 and observes the waveform displayed on the screen to detect the presence or absence of partial discharge, thereby diagnosing the condition such as deterioration of the insulator. You can do it. It is convenient to use a portable type oscilloscope with good accuracy as this oscilloscope because the partial discharge measurement can be easily performed during periodic inspections. Further, for example, when constructing a system for constantly monitoring partial discharge, the signal amplified by the amplifier 10 is digitized by the A / D converter 12 and supplied to the computer 13, and the computer 13
May be used to perform automatic recording and other processing. Further, by the processing of the computer 13, for example, when a pulse of a certain magnitude is detected, a warning is sounded, so that an accident prediction system can be constructed.

[0008]

As described above, according to the present invention, the deterioration diagnosis device for inspecting the condition such as the deterioration of the insulator provided in the prefabricated joint has a small variation due to the individual mounting method and is always substantially constant. Since it is possible to provide a certain quality, it is possible to perform a highly reliable diagnosis as a live line insulation diagnosis, and in particular, it becomes possible to detect peeling voids in the epoxy unit. Further, according to the deterioration diagnosing method of the present invention, it is possible to perform the insulation diagnosis for continuous monitoring by connecting the computer or the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a prefabricated joint to which a deterioration diagnosis device according to the present invention is attached.

FIG. 2 is a partial sectional view showing an overall view of a prefabricated joint to which the deterioration diagnosis device according to the present invention is attached.

FIG. 3 is a configuration block diagram showing a deterioration diagnosis device according to the present invention.

FIG. 4 is a wiring diagram showing a non-grounded type circuit used in a conventional partial discharge measurement method.

FIG. 5 is a wiring diagram showing the same ground type circuit.

FIG. 6 is an explanatory view showing a conventional metal foil electrode method.

FIG. 7 is an explanatory diagram showing a conventional REDI sensor.

[Explanation of symbols]

 1 High-voltage cable 2 Shielding conductor 4 Detection terminal 5 Epoxy unit (insulator) 6 Rubber stress relief cone (insulator) 7 Cable insulator (insulator)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hajime Takehana 1-5-1 Kiba, Koto-ku, Tokyo Inside Fujikura Stock Company

Claims (2)

[Claims] 1. A deterioration diagnosis device for a prefabricated joint, which detects the presence or absence of abnormalities such as deterioration and voids in an insulator provided in a prefabricated joint of an insulated cable, the device being formed on a shield conductor in contact with the insulator. A deterioration diagnosis device for a prefabricated joint, comprising: a detection terminal having one end embedded integrally with a resin in the recess, and a capacitor formed between the shield conductor and the detection terminal. 2. A prefabricated joint deterioration diagnosing method for detecting the presence or absence of deterioration or an abnormal portion such as a void in an insulator provided in a prefabricated joint of an insulated cable, the method being formed on a shield conductor in contact with the insulator. A method of diagnosing deterioration of a prefabricated joint, which comprises diagnosing the presence or absence of an abnormal portion of the insulator by a partial discharge signal output from a detection terminal having one end embedded integrally with resin in a recess.