JPH06201753A - Abnormality reporting method for cable corrosion-proof layer protective device - Google Patents

Abstract

PURPOSE:To detect the abnormality of a cable corrosion-proof layer protective device at a low cost. CONSTITUTION:An optical fiber 20 is inserted into a cap-like terminal 7 fixed to a terminal opening section 29 protruding an abnormality display mechanism 6 via the abnormal current of a cable corrosion-proof layer protective device, a light transmitter 21 using a light emitting diode as a light source is connected to one end of the optical fiber 20, a light receiver 22 using a photo-diode as a sensor is connected to the other end, and the detection light from the inexpensive light emitting diode having a small luminescence output can be detected by the inexpensive photo-diode. When the abnormality display mechanism 6 is protruded, a cutter 26 is pressed to the optical fiber 20 to cut it, and an abnormality is reported.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality notifying method for notifying a failure due to deterioration of a cable anticorrosion layer protecting device for protecting a cable from a surge input, and particularly, to make the notification inexpensive and reliable. The method of notifying an abnormality of the cable corrosion protection layer protection device.

[0002]

2. Description of the Related Art Cable lines that are constantly exposed to surges such as lightning and opening and closing of a circuit breaker are generally protected by the surges in order to prevent the cable line's corrosion protection layer from being damaged and becoming unusable. A grounded arrester composed of a silicon carbide (SiC) varistor element and a discharge gap inserted in series with the element is provided between the element and the ground.

Due to the discharge gap, this arrester with a gap does not operate when a normal voltage is applied to the cable line, an overvoltage is generated in the cable line due to the surge, and the generated voltage reaches the discharge start voltage. At the time of abnormalities, the abnormal current due to the overvoltage is discharged to the ground by the discharge gap impulse discharge, and then the overvoltage applied to the cable line is limited by the non-linear resistance characteristic of the varistor element, and the damage of the anticorrosion layer of the cable line is prevented. It is like this.

By the way, in this arrester with a gap, since there is a discharge delay, the protective characteristic is not so good. Since the gap has to be formed, the device becomes large and heavy. Due to such problems, a gapless arrester using a zinc oxide (ZnO) element has been used in recent years.

In the gapless arrester using this zinc oxide element, since the zinc oxide element exhibits a remarkably non-linear characteristic as compared with the silicon carbide element, a constant current does not flow even if it is not insulated by the discharge gap and a surge voltage is generated. Since the current can flow only when there is an abnormality when the limit voltage is reached, there is no need for a discharge gap and there is no discharge delay, so the protection characteristics are improved. Surge processing capacity is improved. Can be small and lightweight. On the other hand, since it is gapless, voltage stress is constantly applied to the zinc oxide element, and if the zinc oxide element is used for a long period of time, it is necessary to consider the deterioration of the voltage applied to the zinc oxide element.
There is a problem that leakage current increases due to element deterioration and element temperature rise, thermal runaway occurs, the element is destroyed, and the cable line cannot be protected.

Therefore, in the gapless arrester using such a zinc oxide element, as shown in FIG. 4, for example, it is possible to prevent thermal runaway from occurring in the outer peripheral container composed of the mold insulator 25 and the cap-shaped terminal 7. It is used as a cable anticorrosion protection device which is built in together with the abnormality display mechanism 6 for displaying and can display the abnormality of the gapless arrester 3.

The abnormality display mechanism 6 has a display plate 1 attached to the tip and a metal wire 4 attached to the end face of the gapless arrester 3 by soldering 2 at the other end, and a compression spring 5 inserted through the metal line 4. When an abnormal current flows through the gapless arrester 3 and the element 3'deteriorates and causes thermal runaway, the heat generated thereby melts the solder that fixes the metal wire 4, causing the metal wire 4 to open the terminal by the spring 5. The display plate 1 at the end protruding from the portion 29 can be confirmed from the detection window 8 provided on the cap-shaped terminal 7, and the gapless arrester 3 that has deteriorated and caused an abnormality can be identified.

However, in such a display mechanism 6, the worker has to go to the place where the protective device is installed in order to check the deterioration, so that the efficiency is very low and there is a time lag before the abnormality is detected. There was a problem.

Therefore, for example, as shown in FIG. 3, a contact 9 is provided inside the cap-shaped terminal 7, and a connecting wire 10 attached to the contact 9 is connected to a detection circuit 11 provided at a remote monitoring station. When the connection causes an abnormal current to flow and the abnormality display mechanism 6 projects, the contact 9 is short-circuited, and the short circuit is detected by the detection circuit 11 to notify the abnormality.

However, in this method, since the detection signal is an electrical signal, the detection signal is affected by noise such as surge, the detection circuit 11 is apt to malfunction, and the contact also causes contact failure. There is a problem of low reliability.

As a solution to this problem, Japanese Patent Publication No. 3-
There is an abnormality notification method proposed in Japanese Patent No. 40574.

In this method, as shown in FIG. 2, the ends of the optical fibers 20 are attached to the opposing positions of the cap-shaped terminals 7, and one of the optical fibers 20 is attached to the light emitter 21.
In addition, the other side is connected to the light receiver 22, and the abnormality display mechanism 6 protrudes at the time of abnormality to block or reduce the light, so that the light detection device 23 and the alarm device 24 connected to the light receiver 22.
This makes it possible to detect and report an abnormality without being affected by surges and without using contacts, and also to centrally manage the device at a remote location.

[0013]

However, in the above abnormality notification method, in order to block the detection light by the protrusion of the abnormality display mechanism, the detection light transmitted by the optical fiber to the end of the optical fiber of the cap-shaped terminal is detected. Through the space in the cap-shaped terminal, the end of the optical fiber provided at a position facing the terminal is configured to receive light, but when propagating through the space in the cap-shaped terminal, the detection light is
Since the light is diffused and greatly attenuated by particles in the air, it is necessary to use a laser light source having a high emission power as the light source of the light emitter with a narrow beam. In addition, it is necessary to use a high-sensitivity sensor for the sensor of the light receiver to detect the attenuated detection light.
Since such a laser light source and a light receiving sensor are expensive,
This is a major problem in reducing the cost of the protection device.

Therefore, an object of the present invention is to provide an inexpensive detection method using an optical fiber which is not affected by a surge and which is excellent in noise resistance.

[0015]

In order to solve the above problems, according to the present invention, a cable-corrosion preventive structure is provided in which an abnormality display mechanism and a gapless arrester are built in, and a cap-shaped terminal is fixed to a terminal opening through which the abnormality display mechanism projects due to an abnormal current. An optical fiber that is inserted into the cap-shaped terminal is provided for the layer protection device,
The inserted optical fiber is provided with a cutter means that is pressed against the protrusion of the abnormality display mechanism, and one of the optical fibers is connected to a light emitter and the other is connected to a light receiver. A method was used in which a cutter means was pressed against the optical fiber to cut the optical fiber to notify the abnormality.

[0016]

In the abnormality notification method for such a cable anticorrosion protection device, the detection light is incident on the optical fiber by the light emitter,
An abnormality of the protection device is monitored by detecting the incident detection light with a light receiver. At this time, since the transmission path of the detection light from the light emitter to the light receiver is formed by the optical fiber and is not transmitted in the space medium, the amount of the detection light received by the light receiver is small. Therefore, it is not necessary to use a laser light source having a large emission power and a narrow beam, and a sensor having a high sensitivity as a light emitting source of the light receiver.

Then, for example, when an abnormal current flows through the device and the abnormality display mechanism is projected, the cutter means is pressed against the optical fiber by the projection, and when the optical fiber is cut, it is transmitted to the light receiver by the optical fiber. The detected light is blocked, the detected light is not input to the light receiver, and the abnormality is notified.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

The cable anticorrosion layer protection device according to the present invention shown in FIG. 1 includes an abnormality display mechanism 6 and a gapless arrester 3.
And an outer peripheral container including a mold insulator 25 containing them and a cap-shaped terminal 7 on which a hot-side terminal is formed,
The optical fiber 20 for detection, the cutter 26 for cutting the optical fiber 20, and the light emitter 2 connected to the optical fiber 20.
1 and a light receiver 22.

The gapless arrester 3 is a zinc oxide element 3'having a ground-side terminal 27 formed on one end surface thereof, and is molded with a mold insulator 25.
An opening 28 reaching the end face of the gapless arrester 3 is formed in the mold insulator 25, and a cylindrical line-side terminal opening 2 having a lower end bent inward is formed at the opening end.
9 is attached.

An abnormality display mechanism 6 is provided inside the line-side terminal opening 29. The abnormality display mechanism 6 is composed of a metal wire 4 having a display plate 1 formed at its tip and a spring 5. The spring 5 is inserted into the metal wire 4, and the other end of the metal wire 4 is a mold insulator. 25 openings 2
8 and is soldered 2 to the end face of the gapless arrester 3. Therefore, the spring 5 is held in a compressed state by the bending of the lower end of the line side opening 29 and the display plate 1 of the metal wire 4, and when the solder is melted by the heat generation of the gapless arrester 3, the spring 5 expands. Then, the metal wire 4 is projected from the line-side terminal opening 29.

On the other hand, a screw groove is formed on the outer side of the line side terminal opening 29, and the cap-shaped terminal 7 having a screw groove formed on the inner wall for screwing with the screw groove is screwed and fixed. There is. Here, reference numeral 30 in the drawing denotes a lock nut which prevents the screwing of the cap-shaped terminal 7 from loosening.

Inside the cap-shaped terminal 7, the metal wire 4 is
The cutter 26 is at the position where the display plate 1 of
It is attached with the bottom.

The cap-shaped terminal 7 has an insertion hole 31.
Is provided, and the cap-shaped terminal 7 is inserted through the insertion hole 31.
The optical fiber 20 is inserted through the inside of the. As shown in FIG. 1, the optical fiber 20 inserted through the inside of the cap-shaped terminal 7 is installed at a cutting edge 26 'of the cutter 26 with a space of several mm, and is fixed by, for example, an adhesive. Due to the protrusion of 6, the blade tip 26 ′ of the cutter 26 is pressed and cut.

On the other hand, at one end of the optical fiber 20, a light emitting device 2 using an inexpensive light emitting diode as a light source is provided.
1 is connected to the other side, and the other side is also connected to a light receiver 22 using an inexpensive photodiode sensor. The detection light output from the light emitting diode of the light emitting device 21 is transmitted through the optical fiber 20 in the cap-shaped terminal 7 and is incident on the light receiving device 22, so that the light emitting device 2 reaches the light receiving device 22.
The attenuation amount of the detection light from the light source 1 is small, and as described above, the light emitting diode having a small output is used as the light source of the light emitter 21,
Even if a photodiode having low sensitivity is used for the light receiver 22, the detection light output from the light emitter 21 can be sufficiently detected. Therefore, the light emitter 21 and the light receiver 22 can be manufactured at low cost. The output of the light receiver 22 is connected to, for example, the notification circuit 32, and when the incident light decreases and the input level of the detection light from the light receiver 22 decreases, the decrease is determined and the notification output is output. ing.

This embodiment is constructed as described above. Next, the abnormality detecting method will be explained by describing the operation of this apparatus.

In this device, the hot side terminal is connected to the cable line, the ground side terminal 27 is grounded, and the detection light is incident on the optical fiber 20 from a light emitter 21 provided at a remote place such as a monitoring station. The detection light incident on the optical fiber 20 is detected by the light receiver 22 to monitor the abnormality of the device.

Now, for example, a surge occurs on the line due to the occurrence of lightning, and the surge current is generated by the cap-shaped terminal 7 →
The line side terminal opening 29 → flows to the gapless arrester 3 via the abnormality display mechanism 6, and when the surge is discharged to the ground, the gapless arrester 3 deteriorates and causes thermal runaway. The solder on the end face is melted, the abnormality display mechanism 6 projects from the line-side terminal opening 29, and the display plate 1 presses the optical fiber 20 against the cutter 26. Therefore, the optical fiber 20 is cut, and the detection light to be propagated to the light receiver 22 by the optical fiber 20 is blocked at this cutting point and does not reach the light receiver 22. As a result, the detection output is not output from the light receiver 22, and the notification circuit 32 notifies the abnormality.

As described above, according to this detection method, the optical fiber 20 inserted into the cap-shaped terminal 7 is cut to detect the abnormality and notify the detected light. Decrease the attenuation of
Abnormalities can be detected without using a laser light source having a large light emission output and a sharp beam as a light source of the light emitter, and without using a highly sensitive sensor for the light receiver 22.

Further, since the attenuation of the detection light during transmission can be made extremely small in this way, the installation distance of the light receiver 22 can be extended and a large number of the above devices can be provided by a pair of infrared light emitting diodes and photodiode sensors. Since it is possible to monitor, it is possible to collect the light receivers of the devices attached to the detection line in a wider range than in the past in one place and perform concentrated monitoring, or to collect 3 to 9 of the devices in one place. Further cost reduction is possible by monitoring with a pair of light emitting diodes and a sensor.

Although the display plate is provided at the tip of the metal wire of the abnormality display mechanism in the embodiment, this display plate may be used as a cutter, while the cutter provided in the cap-shaped terminal may be used as the contact portion.

[0032]

According to the abnormality notifying method of the present invention, the abnormality of the cable anticorrosion layer protection device is detected and notified by cutting the optical fiber that transmits the detection light. Therefore, the detection is affected by noise such as surge. Detection can be performed without receiving. Further, at that time, the detection light transmitted between the light emitter and the light receiver is transmitted by the optical fiber and does not propagate through the space in the cap-shaped terminal with large attenuation, so that the detection light from the light emitter reaching the light receiver is Since the amount of attenuation is small and it does not diffuse, it is widely used for the light source of the light emitter and the sensor of the light receiver, and it is easy to obtain and cheap, for example, a light emitting diode with low emission intensity or a photodiode with low sensitivity is used. It can be used, and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment.

FIG. 2 is an enlarged view of a main part of a conventional example.

FIG. 3 is an enlarged view of a main part of a conventional example.

FIG. 4 is a vertical sectional view of a conventional example.

[Explanation of symbols]

 3 Gapless arrester 6 Abnormality display mechanism 20 Optical fiber 21 Light emitter 22 Light receiver 26 Cutter 29 Terminal opening

Claims (1)

[Claims] 1. A cap-shaped terminal for a cable anticorrosion layer protection device, which has a built-in abnormality display mechanism and a gapless arrester, and has a cap-shaped terminal fixed to a terminal opening through which the abnormality display mechanism projects due to an abnormal current An optical fiber that is inserted through the optical fiber is provided, the optical fiber that is inserted through the optical fiber is provided with cutter means that is pressed by the protrusion of the abnormality display mechanism, one of the optical fibers is connected to a light emitter, and the other is connected to a light receiver. An abnormality notification method for a cable anticorrosion layer protection device, characterized in that the abnormality display mechanism is projected and the cutter means is pressed against the optical fiber to cut the optical fiber to notify the abnormality.