JPH06325909A - Detecting device for fault of arrester for protecting of cable corrosionproof layer - Google Patents

Abstract

PURPOSE:To detect a fault in an arrester by a method wherein when the temperature of an arrester body rises abnormally, a shape memory alloy member is deformed, a movable member is displaced by the deformation and a signal is generated from a signal generating element. CONSTITUTION:A stopper 25 made of a shape memory alloy is provided in such a way that it is mounted to an arrester body 17 and reaches roughly the same temperature as that of the body 17 and when the body 17 rises to an abnormal temperature by some cause, the stopper is deformed into a shape, which is previously made to memorize therein, at that temperature and is taken off the catching of a movable rod 27. Whereupon, the rod 27 is pushed down by the repulsive force of a coil spring 31, an optical fiber core 37 is bent (or cut) and the transmission loss of the core 37 is increased. An increase in this transmission loss is detected by an optical power meter 41, whereby it is detected that an abnormality is cuased in the arrester body. Thereby, at the time of generation of a fault in an arrester, countermeasures, such as repair and exchange, can be immediately taken.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a failure of an arrester used for protecting an anticorrosion layer such as a power cable.

[0002]

2. Description of the Related Art An arrester is installed at a terminal connection portion or an intermediate connection portion of a power cable for the purpose of protecting an anticorrosive layer of the power cable. An example thereof is shown in FIG. Reference numeral 11 is a power cable, 13 is a terminal connection portion of the power cable 11, and 15 is an arrester. The arrester 15 is a power cable 11 as shown.
Installed between the sheath and the ground.

[0003]

The arrester 15 may fail when an overvoltage surge occurs. When the arrester fails and its impedance becomes almost zero (when the arrester is in a short-circuit state), an overcurrent flows in the sheath circuit of the power cable, and the allowable current of the power cable decreases. When the arrester fails and its impedance becomes almost infinite (when the arrester opens), the protective function of the cable anticorrosion layer against overvoltage surge is lost, which not only accelerates the deterioration of the anticorrosion layer but also insulates the anticorrosion layer. It may cause destruction.

Conventionally, even if there is a failure of such an arrester, there is no effective means for detecting it, so that the failed arrester is continuously used as it is, and there is a risk of causing the above problems. . An object of the present invention is to provide an arrester failure detection device capable of detecting, when an arrester fails, in view of the above-mentioned problems of the prior art.

[0005]

An arrester failure detection device of the present invention that achieves this object is a shape memory alloy member which is attached to an arrester body and is deformed when the temperature of the arrester body rises abnormally, and this shape. The memory alloy member includes a movable member that is displaced from the first position to the second position when the memory alloy member is deformed, and a signal generating element that generates a signal when the movable member reaches the second position. is there.

An optical fiber core wire or an electrical contact is used as the signal generating element. In the case of the optical fiber core, the signal is generated when the movable member comes to the second position to bend the optical fiber core and increase the transmission loss of the optical fiber. In the case of electric contacts, a signal is generated when the movable member comes to the second position to close (or open) the contacts.

[0007]

[Function] The arrester causes a failure when an overvoltage surge or the like enters the arrester body which determines the characteristics of the arrester and causes an abnormal temperature rise. Therefore, with the above configuration, when the temperature of the arrester body rises abnormally, the shape memory alloy member is deformed, whereby the movable member in the first position is displaced to the second position, and the signal Generate a signal from the generating element. Therefore, by detecting this signal, the arrester failure can be detected.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In general, the arrester 15 is composed of an arrester body 17 having characteristics as an arrester, a storage case 19 for housing the arrester body 17, and a connection terminal 21 for connecting the arrester body 17 to a lead wire or the like.

The arrester 15 is provided with the following failure detection device 23. The failure detection device 23 includes a shape memory alloy stopper 25 attached to the arrester body 17, and a movable rod 27 whose upper end is locked to the stopper 25. The movable rod 27 penetrates the storage case 19 and extends downward, and a collar portion 29 is integrally formed near the lower end thereof. A coil spring 31 is inserted between the collar portion 29 and the storage case 19 in a compressed state. That is, the movable rod 27 is pushed downward by the repulsive force of the coil spring 31, but is held at the illustrated position (first position) in the normal state because it is caught by the stopper 25.

The lower half of the movable rod 27 and the coil spring 31 are housed in an auxiliary case 33 fixed to the housing case 19, and the lower end of the movable rod 27 penetrates through a hole at the bottom of the auxiliary case 33. It can be projected to the outside. Just below the lower end of the movable rod 27 is an optical fiber core wire supported by a holder 35.
37 are arranged. A signal light having a constant intensity is always sent to the optical fiber core wire 37 from a light source 39 connected to one end thereof, and an optical power meter 41 is provided at the other end side of the optical fiber core wire 37.
Is designed to monitor the intensity of the signal light.

Now, the stopper 25 made of the shape memory alloy
Is attached to the arrester body 17 so that the temperature is almost the same as that of the arrester body 17.
When the temperature rises to an abnormal temperature for some reason, it deforms to a shape (shape stored in advance) as shown in FIG. 2 at that temperature, and the movable rod 27 is unhooked. Then, the movable rod 27 is pushed down by the repulsive force of the coil spring 31 and comes to the position (second position) shown in the drawing to bend (or cut) the optical fiber core wire 37, so that the transmission loss of the optical fiber core wire 37 is reduced. To increase. By detecting this increase in transmission loss with the optical power meter 41, it is possible to detect that an abnormality has occurred in the arrester body 17.

The above is one embodiment of the present invention, and the present invention is not limited to this. Shape memory alloy members (stoppers in the above embodiments) and movable members (movable rods and coil springs in the above embodiments). The form of) can be variously changed. Further, although the optical fiber core wire is used as the signal generating element in the above-mentioned embodiment, an electric contact may be used.

[0013]

As described above, according to the present invention, the failure of the arrester for protecting the cable anticorrosion layer can be detected. Therefore, when the failure of the arrester occurs, immediate countermeasures such as repair and replacement are taken. It is possible to protect the cable anticorrosion layer more reliably.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state before failure detection of an arrester failure detection device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state after failure detection of the device of FIG.

FIG. 3 is an explanatory diagram showing a mounted state of an arrester for protecting the cable anticorrosion layer.

[Explanation of symbols]

15: Arrestor 17: Arrestor main body 23: Failure detection device 25: Stopper made of shape memory alloy 27: Movable rod
29: Collar part 31: Coil spring 37: Optical fiber core wire 39: Light source
41: Optical power meter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotsugu Koike 1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Fuji Electric Co., Ltd. (72) Masahiro Iizumi 2-chome, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Takao Nakano 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (1)

[Claims] 1. A shape memory alloy member which is attached to an arrester body and is deformed when the temperature of the arrester body rises abnormally, and when the shape memory alloy member is deformed, it is displaced from a first position to a second position. A failure detection device for a cable corrosion protection layer arrester, comprising a movable member and a signal generating element that generates a signal when the movable member reaches a second position.