JPH06109555A - Temperature monitor for power line - Google Patents

Abstract

PURPOSE:To obtain a system for accurately monitoring abnormal heating of a power line under the hot-line state without requiring visit of worker to the site. CONSTITUTION:A power line 1 is fixed with a shape memory alloy 2 which separates, at the tip thereof, from the power line 1 when a set temperature is exceeded to produce corona discharge. A section 4 for detecting discharge current or discharge field due to corona discharge is installed in the vicinity of the shape memory alloy 2 in order to transmit data to an operational processor 12 in a substation or a control station or to operate a display 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power line temperature monitoring device for monitoring an abnormal temperature rise of a power line such as a power transmission line or a busbar connecting portion in a substation.

[0002]

2. Description of the Related Art In order to maintain long-term reliability of power lines such as power transmission lines and busbar connection parts in substations, in addition to monitoring the mechanical strength deterioration of busbar compression parts and clamp parts, It is necessary to regularly inspect those parts for abnormal heat generation.

For this reason, a power line monitoring device called a wire sleeve inspection device has been conventionally used. This is a device in which a sensor is brought into contact with the outer surface of the electric wire sleeve of the busbar compression portion or the clamp portion, and the abnormality is detected by methods such as magnetic field line detection, magnetic permeability detection, and DC magnetic field detection. However, there are problems such as the need for power outage work and the poor workability because the worker needs to go to the busbar compression section and the clamp section, which are located slightly away from the tower.

In addition to the above, there is a device for detecting abnormal heat generation by the infrared detection system, but the image system has a large size and is expensive, and the infrared thermometer outputs a value averaged with the ambient temperature. There is a problem with poor accuracy. There is also a method of attaching a thermo label to the electric power line, but this requires a worker to visually check each tower by observing each tower, which leaves many problems.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and enables accurate monitoring of abnormal heat generation of a power line in a live line state, and does not require a worker to visit the site. It has been completed to provide a power line temperature monitoring device.

[0006]

SUMMARY OF THE INVENTION The power line temperature monitoring device of the present invention, which has been made to solve the above problems, causes a corona discharge on the power line when the temperature of the power line exceeds a preset value. The shape memory alloy to be generated is attached, and a detector for detecting the discharge current or the discharge electric field is installed in the vicinity thereof.

[0007]

In the power line temperature monitoring apparatus of the present invention, when the temperature of the power line exceeds the set value, the shape memory alloy attached to the power line bends and its tip is separated from the power line. At this time, if the shape of the shape memory alloy is set so that the spatial electric field strength at the tip of the shape memory alloy is 18 KV / cm or more, corona discharge is generated from the tip of the shape memory alloy. Therefore, if the discharge current or discharge electric field due to this corona discharge is detected by a detection unit installed in the nearby tower, etc., and transmitted to the arithmetic processing unit at the substation or control station, the worker will go to the site. It is possible to accurately monitor the abnormal heat generation of the power line without the need for the live line.

[0008]

The present invention will be described below in more detail with reference to the illustrated embodiments. In FIG. 1, 1 is a high-voltage power line such as a power line or a bus bar in a substation, and 2 is a rod-shaped shape memory alloy attached to a portion of the power line 1 where abnormal heat generation is to be monitored. As is well known, shape memory alloys utilize the change in crystal structure between the martensite phase, which is easily plastically deformed, and the stable austenite phase, and when heated from a deformed state at a low temperature to a high temperature, the initial stability The shape is memorized by utilizing the phenomenon of returning to a different shape. In the present embodiment, the shape memory alloy 2 whose tip is curved in a direction away from the power line 1 when the temperature exceeds the set value is used, and is clamped to the power line 1 by the clamp metal fitting 3.

An electric field is formed around the high-voltage power line 1, but when the shape memory alloy 2 is at the position shown by the alternate long and short dash line, the shape memory alloy 2 is in the same state as being shielded by the power line 1. , The spatial electric field strength at the tip is small. However, if the spatial electric field strength at the tip end is 18 KV / cm or more when curved as shown by the solid line in FIG. 1, corona discharge occurs.

On the other hand, the steel tower or the like supporting the power line 1 is provided with a detector 4 for detecting the discharge current or discharge electric field due to this corona discharge. The detection unit 4 of the embodiment includes a reception antenna 5, a reception unit 6, a determination unit 7, and a transmission device 8.
And a display device 9 and a power supply 10. The determination unit 7 is a unit that determines whether the corona discharge received by the receiving antenna 5 is due to abnormal heating of the power line 1, snowfall, or rainfall. Corona discharge due to rainfall or snow is transient, whereas abnormal heating of the power line 1 is permanent, so a delay circuit can be provided to identify this and prevent malfunction.

The transmission device 8 standardizes the intensity level of the measured value and transmits the data within a predetermined time to the arithmetic processing unit 12 of the substation or control station through the OPGW (overhead ground wire with built-in optical fiber) 11. Device. As a result, the arithmetic processing unit 12 at the substation or control station can automatically monitor the abnormality of each tower periodically, and the worker can know the abnormality without going to each tower.

The display device 9 operates when the discharge current or discharge electric field due to corona discharge continues for a predetermined time at a predetermined level or more. In the embodiment, the hanging screen 13 is hung so that it can be easily observed from a distant position. Is done. Although this display device 9 is not essential, it is convenient for an operator to find a steel tower to be repaired when he goes to the site for repair. As the power source 10, a solar cell or an AC power source can be used.

In the embodiment shown in FIGS. 2 and 3, a fin as a heat radiation means is provided around the clamp metal fitting 3 of the shape memory alloy 2.
14 are formed. In general, shape memory alloys have a usable temperature range of 100 ° C. or lower, whereas the temperature of the power line 1 may reach 150 ° C. For this, fins
The shape memory alloy 2 is cooled by 14 and the temperature of the power line 1 is
It is preferable to protect the shape memory alloy 2 even when the temperature reaches 150 ° C.

4 and 5, the clamp metal fitting 3 of the shape memory alloy 2 as described above is formed in a U shape so that it can be attached to the live power line 1 by the live wire operating rod 15. It is the one. This makes it possible to eliminate power outage work, and to easily attach the shape memory alloy 2 to the existing power line 1.

By the way, when the shape memory alloy 2 reaches a predetermined temperature and returns to the original stable austenite phase and then bends, the shape memory alloy 2 maintains its shape even after the temperature is lowered, and does not return to a straight line by itself. For this reason, in the above-described example, it is necessary for the worker to apply a force to the curved shape memory alloy 2 to restore it to the straight shape. Therefore, in the examples of FIGS. 6 and 7, a restoring means is provided in which the spring 2a made of a shape memory alloy and the spring 2b made of a normal metal are joined in series. According to this structure, when heated to a predetermined temperature or higher, the shape memory alloy spring 2a extends while pressing the spring 2b, which separates the tip end thereof from the power line 1 as shown in FIG. When the temperature decreases, the force of the ordinary metal spring 2b becomes larger than the force required to plastically deform the shape memory alloy spring 2a,
The original shape of FIG. 6 can be restored again.

Further, as shown in FIGS. 8 and 9, it is also possible to provide a restoring means in which a spring 2a made of a shape memory alloy and a spring 2b made of a normal metal are arranged in parallel to perform the same operation as described above. . If configured as shown in FIGS. 6 to 9, the shape memory alloy can be automatically returned to a state in which no corona discharge is generated after abnormal heat generation of the power line 1 disappears,
It is possible to eliminate the need for the worker to go to the site and return to a straight line.

[0017]

As described above, according to the power line temperature monitoring device of the present invention, it is possible to accurately monitor abnormal heat generation of the power line in a live line state, and it is necessary for the worker to go to the site. There is no. This device can also be used to determine the load current energization allowable value of the power line. That is, the load current energization allowable value of the power line is determined by the temperature rise limit value of the power line. It can also be expected to be drained, which will lead to an improvement in the reserve capacity of power generation.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a front view showing a shape memory alloy provided with heat dissipation means.

FIG. 3 is a side view of FIG.

FIG. 4 is a front view showing a shape memory alloy that can be attached to a live wire.

FIG. 5 is a side view showing a shape memory alloy that can be attached to a hot wire and an attachment tool thereof.

FIG. 6 is a front view showing an automatic return type shape memory alloy.

FIG. 7 is a front view showing an operating state of the shape memory alloy of FIG.

FIG. 8 is a front view showing another shape memory alloy of the automatic restoration type.

9 is a front view showing an operating state of the shape memory alloy of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power line 2 Shape memory alloy 4 Detection part 9 Display device 12 Arithmetic processing device 14 Heat dissipation means

Claims (6)

[Claims] 1. A detection unit for mounting a shape memory alloy on a power line, the tip of which separates from the power line when a temperature exceeds a set value to generate corona discharge, and which detects the discharge current or discharge electric field in the vicinity thereof. The power line temperature monitoring device is characterized by being installed. 2. The power line temperature monitoring device according to claim 1, further comprising a display device which operates when a discharge current or discharge electric field due to corona discharge is maintained at a predetermined level or higher for a predetermined time. 3. The power line temperature monitoring device according to claim 1, wherein data within a predetermined time is transmitted to an arithmetic processing unit at a substation or a control station, and the arithmetic processing unit monitors an abnormality of the power line. 4. The power line temperature monitoring device according to claim 1, further comprising a delay circuit for preventing malfunction due to rainfall or snow. 5. The power line temperature monitoring device according to claim 1, wherein the shape memory alloy is provided with a heat radiating means. 6. The power line temperature monitoring device according to claim 1, wherein the restoring means is incorporated in the shape memory alloy.