JP2001167860A - Method of monitoring temperature of compression joint tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of monitoring temperature of a compression joint tube using a shape memory alloy that can detect abnormal overheating of the compression joint tube and prevent corona noise, as variation by shape memory effect is generated in a direction that is not protruded from the compression jointing tube. SOLUTION: A shape memory alloy 5 is wound on a compression jointing tube 3a of an electric transmission line in coil shape. Before and after the compression jointing tube 3a is overheated, abnormal overheating of the compression jointing tube 3a is detected visually by monitoring the change in the coil pitch by using a telescope from a distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring the temperature of a compression connection pipe in an electric wire such as an overhead power transmission line, and more particularly to a method for monitoring the temperature of a compression connection pipe using a shape memory alloy.

[0002]

2. Description of the Related Art In general, in an overhead power transmission line, a current carrying capacity is increased by increasing an allowable level of heat generation of a transmission line. As a matter to be particularly noted when operating at this high temperature, there is a problem of heat generation at the wire connection part.

[0003] Usually, pressurized compression / shrinkage connection by a compression connection pipe (compression sleeve) is employed for fixing the electric wires to the tower or connecting the electric wires to each other. In the case of this connection type, electrical conductivity is ensured by integral contact between the compression connection pipe and the electric wire, but the heat generation of the compression connection portion is generally larger than that of the electric wire body.

[0004] Factors of heat generation include, for example, oxide films,
Inhibition of conductivity due to the presence of an anticorrosion film or the like, the use of an old wire that is particularly large in the inhibition of conduction, or eccentric connection, salt damage, zinc reaction, etc., are mentioned, and these factors have a large effect on high-temperature operation as the transmission capacity increases. Become like

Therefore, in order to detect such a limit of heat generation, a shape memory alloy is provided on a compression connection pipe of an electric wire, and when the temperature reaches a certain temperature, the shape of the shape memory alloy changes. Techniques for informing are known.

For example, there are the following methods for monitoring a feeder line (railroad) and a compression connection pipe of a transmission line using a shape memory alloy.

1) Japanese Unexamined Patent Publication No. 63-180533 (A device for detecting abnormal heat generation at a feeder wire connection). That is, when the heat sensor made of the shape memory alloy has no abnormality, the heat sensor is in close contact with the connection pipe, but abnormal heat generation occurs and the temperature of the connection pipe reaches a predetermined temperature (10 ° C.).
(0 ° C), it rises away from the surface of the connecting pipe.

2) Japanese Patent Application Laid-Open No. 2-181372 (heat detecting device for connecting portion of feeder wire). That is, when there is no abnormality in the heat sensor made of the shape memory alloy, the heat sensor is in close contact with the connecting portion of the feeder wire, but when abnormal heat is generated and the temperature of the connecting tube reaches a predetermined temperature (70 ° C.), the surface of the connecting tube becomes One that rises away and deforms the entire heat sensor into a U-shape.

3) Japanese Unexamined Utility Model Publication No. Sho 62-104129 (temperature detecting device). That is, as shown in FIG. 4 (a), a part of a strip-shaped detection piece 13 made of a shape memory alloy is attached to a member 12 for compressing and retaining such as a clamping clamp, a sleeve, and a compression terminal used for a power transmission and distribution wire 11. A crimp-locking mechanism that changes from a horizontal state to a V-shape or sag when the temperature limit is reached so that it can be visually detected.

4) Japanese Patent Application Laid-Open No. 4-359883 (abnormal heat generation detection device for sleeve crimping portion). This is to detect an abnormal rise in the temperature of the compression connection pipe section of an overhead transmission line such as an ultra-high-voltage transmission line, and is connected by a compression connection pipe (compression sleeve) 14 as shown in FIG. A pin 17 made of a shape memory alloy is attached to the sleeve crimping portion of the conductor 11a, and when abnormal heat generation occurs in the sleeve crimping portion, the pin 17 is heated, and the pin 17 is instantaneously restored to the stored linear shape. Then, the connection of the bracket 16 is released, and the urging force for restoring the sign body 15 made of a coil spring into a linear shape is applied. Therefore, the pin 17 comes out of the hole of the bracket 16 and the sign body 15 is disengaged. It comes off the surface of the compression sleeve 14. Thus, the sign 15 is made to fall.

[0011]

However, in the above-mentioned prior arts, any of the above-mentioned prior arts is of a type in which a heat sensor made of a shape memory alloy rises away from the surface of the connection pipe at the time of abnormal overheating. For example, Japanese Unexamined Utility Model Publication No. Sho 62-104129 (Temperature Detector) shown in FIG. 4A and Japanese Unexamined Patent Application Publication No. 4-359883 (Urgent Heat Detector for Sleeve Crimping Section) shown in FIG. In this case, when the maximum temperature is reached, the shape memory alloy changes and becomes a projection or a straight line. For this reason, in the case of the conventional method of monitoring the temperature of the compression connection pipe using the shape memory alloy, the potential gradient (Gmax)
There are problems such as the occurrence of corona noise on a high track.

Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art and to make it possible to detect abnormal overheating due to the shape memory alloy by making the change due to the shape memory effect not to protrude from the compression connection pipe. It is an object of the present invention to provide a method of monitoring the temperature of a compression connection pipe which solves a problem such as noise and can easily detect the presence or absence of abnormal overheating.

[0013]

In order to achieve the above object, a method for monitoring the temperature of a compression connection pipe according to the present invention comprises mounting a shape memory alloy on a compression connection pipe of an electric wire, and allowing the compression connection pipe to reach a predetermined limit temperature. An abnormal overheating of the compression connection pipe is detected by utilizing the fact that the shape memory alloy changes along the surface of the compression connection pipe when it reaches (claim 1). In this case, the predetermined limit temperature is set to the highest attainable temperature when the compression connection pipe is overheated due to aging (claim 2).

According to the present invention, the restoration direction of the shape memory alloy that transforms when the compression connection pipe reaches a predetermined limit temperature is
Since the direction changes along the surface of the compression connection pipe, there is no portion that protrudes from the compression connection pipe as compared with the conventional configuration in which the shape memory alloy rises from the surface of the compression connection pipe. Therefore, occurrence of corona noise or the like can be eliminated, and the presence or absence of abnormal overheating can be easily detected.

The method for monitoring the temperature of a compression connection pipe according to the present invention is, specifically, a method in which the shape memory alloy is wound in a coil shape around a compression connection pipe of an electric wire, and before and after the compression connection pipe abnormally heats up. An abnormal overheating of the compression connection pipe is detected by visually observing a change in the coil pitch from a distant place using a telescope, for example. Alternatively, the shape memory alloy is formed as a band-shaped or linear member, which is wound in a coil around a compression connection pipe of an electric wire, and when the compression connection pipe is abnormally overheated, the coil pitch becomes small or changes. By detecting the change visually with a telescope from a distance, for example, abnormal overheating of the compression connection pipe is detected (claim 4).

By mounting the shape memory alloy in a coil shape and reading the change in pitch as described above, the corona characteristics can be improved.

The material of the shape memory alloy is Ti-N
It is preferable that the alloying ratio of Ni is set to 54.5% by weight or less in consideration of a temperature range to be detected using an i-alloy (claim 5).

Preferably, the shape memory alloy is a shape memory alloy coated with a thin resin coat. This is because even when the compression connecting pipe is made of an aluminum alloy, corrosion due to dissimilar metal contact with the aluminum part can be prevented.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 1 shows a configuration of a compression clamp portion in a retaining device such as a steel tower of an overhead transmission line. Compression clamp 1
Is formed as an L-shape as a whole, has a hole 2 at the L-shape corner for fixing to a steel tower via an insulator or the like, and a compression connection pipe (compression sleeve) 3a in one arm of the L-shape. And a compression connection tube 3b on the other arm. And
An electric wire 4a constituting a transmission line is compression-connected to the one-side compression connection pipe 3a, and the other-side compression connection pipe 3b
Is connected to the electric wire 4b by compression.

As shown in FIG. 2, three heat generating points of the compression connection pipe in the overhead transmission line are considered to be a clamp port A, a jumper socket connection section B, and a jumper socket port C.

In the present embodiment, attention is paid to the fact that the compression connection pipe 3a extends in the lateral direction and is easy to mount, and as a typical location, a shape memory alloy is applied to the clamp opening A of the compression connection pipe 3a. Installing.

That is, as shown in FIG. 1A, a band-shaped or linear heat sensor made of a shape memory alloy 5 is wound in a coil shape around the clamp opening A of the compression connection pipe 3a.
When the compression connecting pipe 3a reaches a predetermined limit temperature, the shape memory alloy 5 changes its coil pitch from a large pitch shown in FIG. 1A to a small pitch shown in FIG. 1B (or vice versa). 2) The shape is stored so as to change. The predetermined limit temperature, that is, the transformation temperature of the shape memory alloy 5 is set to a maximum attainment temperature, for example, 100 ° C. when the compression connection pipe is overheated due to aging.

Now, it is assumed that the temperature of the connecting portion has risen and is in an abnormal overheating state. When the temperature of the compression connection pipe 3a rises to a predetermined limit temperature, that is, the temperature at which the shape memory is stored, the coil pitch of the shape memory alloy 5 is changed from the large pitch shown in FIG. To the small pitch shown (or vice versa)
Change. Therefore, by reading the change in pitch before and after overheating with a transit (a high-magnification telescope), it is possible to easily visually recognize it from a distance and detect abnormal overheating.

The features of the method for monitoring the temperature of the compression connection pipe are as follows.
The shape memory alloy 5 for monitoring the temperature is connected to the compression connection pipe 3a.
The shape memory alloy 5 does not rise away from the surface of the compression connection pipe 3a as in the related art because of the method in which an abnormality is detected by a change in pitch before and after overheating. That is, the shape memory alloy 5 only changes along the surface of the compression connection pipe 3a, and the shape memory alloy 5 does not change into a projection shape even if abnormal overheating is detected as in the related art.
For this reason, corona noise does not occur even on a line with a high potential gradient.

The best way to wind the shape memory alloy 5 is to directly wind the shape memory alloy 5 around the compression connection pipe 3a of the compression clamp 1 as described above. However, the shape memory alloy 5 can be wound around the compression connection pipe 3a via an intermediate member.

It is desirable that the wire diameter of the shape memory alloy 5 to be wound is in the range of 0.8 mm to 1.5 mm from the viewpoint of the attachment to the compression connection pipe 3a and the accuracy of the detection temperature. .

As the material of the shape memory alloy that can be used, for example, Ti—Ni alloy, Au—Cd alloy, C
There is a u-Zn-Al alloy or the like, and any of them may be used. The transformation temperature can be set to various values by changing the alloy composition. However, it is preferable to use a Ti—Ni-based alloy that is widely available on the market. As can be seen from the relationship between the Ni content and the shape recovery temperature shown in FIG. Is preferably set to 54.5% by weight or less to detect Ni.

When the compression connection pipe 3a on which the shape memory alloy is mounted is made of an aluminum alloy, a thin resin coat is applied to the shape memory alloy 5 in order to prevent corrosion due to dissimilar metal contact with the aluminum portion. Good to apply.

[0030]

As described above, according to the present invention, the following excellent effects can be obtained.

(1) According to the first or second aspect of the present invention, the restoration direction of the shape memory alloy which is transformed when the compression connection pipe of the electric wire reaches a predetermined limit temperature is set along the surface of the compression connection pipe. Therefore, compared to the conventional configuration in which the shape memory alloy rises from the surface of the compression connection pipe, there is no portion protruding from the compression connection pipe. Therefore, it is possible to accurately and easily detect the presence or absence of abnormal overheating by monitoring the temperature of the compression connection pipe of the transmission line while eliminating the occurrence of corona noise and the like.

(2) According to the third or fourth aspect of the present invention, specifically, the shape memory alloy is wound in the form of a coil around the compression connection pipe of the electric wire, and its restoration direction is changed in the direction of the change in the coil pitch. Detects abnormal overheating of the compression connection pipe by visually observing the change in coil pitch before and after the compression connection pipe overheats, for example, using a telescope from a distance, with the direction changing along the surface of the compression connection pipe. Therefore, it is necessary to monitor the temperature of the compression connection pipe of the transmission line and accurately and easily detect the presence or absence of abnormal overheating while eliminating the parts protruding from the compression connection pipe and eliminating the occurrence of corona noise etc. Can be.

(3) According to the fifth aspect of the present invention, a Ti-Ni alloy is used as the material of the shape memory alloy, and the mixing ratio of Ni is 54.5% by weight in consideration of the temperature range to be detected.
Because of the following, the shape recovery temperature can be set to a high temperature of 90 ° C. or higher.

(4) According to the sixth aspect of the present invention, since the shape memory alloy is coated with a thin resin coat, even if the compression connection pipe is made of an aluminum alloy, the metal is different from the aluminum part. Corrosion due to contact can be prevented.

[Brief description of the drawings]

FIG. 1 shows an example of mounting a shape memory alloy according to the present invention, wherein (a) is a view showing a form of the shape memory alloy before overheating,
(B) is a figure which shows the form of the shape memory alloy after overheating.

FIG. 2 is a view showing a heat generating portion of a compression connection pipe.

FIG. 3 is a diagram showing a relationship between a Ti—Ni mixing ratio of a shape memory alloy and a shape recovery temperature.

FIG. 4 is a diagram showing an example of mounting a conventional shape memory alloy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compression clamp 2 Hole 3a, 3b Compression connection pipe 4a, 4b Electric wire 5 Shape memory alloy A Clamp mouth B Jumper socket connection C Jumper socket mouth

Claims (6)

[Claims] 1. A shape memory alloy is mounted on a compression connection pipe of an electric wire, and the shape memory alloy changes along the surface of the compression connection pipe when the compression connection pipe reaches a predetermined limit temperature. A method for monitoring the temperature of a compression connection pipe, comprising detecting abnormal overheating of the compression connection pipe. 2. The method for monitoring the temperature of a compression connection pipe according to claim 1, wherein the predetermined limit temperature is set to a maximum attained temperature when the compression connection pipe is overheated due to aging. 3. The shape memory alloy is wound in a coil shape around a compression connection pipe of an electric wire, and a change in coil pitch before and after the compression connection pipe is abnormally overheated is visually recognized, so that the compression memory connection pipe is formed. The method for monitoring the temperature of a compression connection pipe according to claim 1 or 2, wherein abnormal overheating is detected. 4. The method according to claim 1, wherein said shape memory alloy is formed as a band-shaped or linear member and wound in a coil shape around a compression connection pipe of an electric wire, and the coil pitch is reduced when the compression connection pipe is abnormally heated. The method for monitoring the temperature of a compression connection pipe according to claim 1 or 2, wherein abnormal overheating of the compression connection pipe is detected by visually grasping a large change. 5. The material of said shape memory alloy is Ti-Ni.
5. The method of monitoring a temperature of a compression connection pipe according to claim 1, wherein an alloy is used, and a compounding ratio of Ni is set to 54.5% by weight or less in consideration of a temperature range to be detected. 6. The shape memory alloy according to claim 1, wherein said shape memory alloy is coated with a thin resin coat.
The method for monitoring the temperature of a compression connection pipe according to 2, 3, 4 or 5.