JPH06347451A - Deterioration monitoring method for aerial distribution line - Google Patents

Abstract

PURPOSE:To provide a deterioration monitoring method for aerial distribution lines, which can make inspection at all times without hands, and can monitor the aforesaid line remotely. CONSTITUTION:A communication line 14 is provided in parallel with an aerial distribution line 12, and concurrently, a sound sensor detecting sound radiation caused by the deteriorated section of the serial distribution line 12, and a transmitting line transmitting the output of the sound sensor is provided for an insulator 3 supporting the aerial distribution line 12. The transmitting line is connected to the communication line 14, so that the deterioration of the aerial distribution line 12 is thereby monitored by means of sound radiation via the communication line 14.

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 deterioration of an overhead distribution line by detecting acoustic radiation from a deteriorated portion of the overhead distribution line and inspecting the deterioration of the overhead distribution line, and particularly, without requiring any manpower The present invention relates to a method for monitoring deterioration of an overhead distribution line that can be inspected at any time and can be remotely monitored.

[0002]

2. Description of the Related Art An overhead distribution line may be deteriorated due to fatigue cracks in the wires and the like in the overhead distribution line due to abnormal vibration caused by wind. In particular, fatigue cracks are likely to occur in the wire at the fixing portion where an overhead distribution line such as a discharge clamp is fixed to a utility pole or the like. If this deterioration becomes serious, it may lead to total breakage of the overhead distribution line, and a deterioration inspection of the overhead distribution line is performed to prevent such an accident.

[0003] Conventionally, generally, in order to inspect the deterioration of an overhead distribution line, a deteriorated portion is searched for, and various methods described below are adopted or devised for such a flaw detection method.

First of all, there is a method in which a person climbs on a power distribution pole and visually inspects an overhead line for flaw detection.

Secondly, there is a flaw detection method using an eddy current. This uses a sensor that applies a high-frequency electromagnetic field to generate an eddy current in the overhead distribution line and detects a reaction due to this eddy current. Since the sensor changes its output depending on the presence or absence of the deteriorated portion, it is possible to detect flaws in the overhead distribution line.

Thirdly, there is a flaw detection method using X-rays.

Fourthly, there is an AE method for detecting acoustic radiation such as ultrasonic waves from a defective portion. The AE method is a method in which an acoustic sensor for detecting ultrasonic waves is attached to an overhead distribution line and a portion of the overhead distribution line is forcibly vibrated to detect an elastic wave generated when a fatigue crack develops. An acoustic sensor used for such a purpose is called an AE sensor.

The outline of the AE method will be described. As shown in FIG. 6, a holder 6 having an acoustic sensor built in at the inspection site.
1. Bring in the vibrating rod 62 and the analyzer 63, and hold the holder 61
Is attached to the tip of the insulating rod 64 and is mounted in the vicinity of the discharge clamp 65 of the overhead distribution line 12, while the overhead distribution line 12 is forcibly excited by the vibration rod 62. When acoustic radiation is generated in the deteriorated portion due to forced vibration, the acoustic radiation is detected by the acoustic sensor and transmitted to the analysis device 63 installed on the ground via the cable.
The analysis device 63 determines the presence or absence of deterioration from the acoustic emission signal.

[0009]

However, each of the four flaw detection methods listed above as conventional techniques has problems.

The method in which the first person climbs up the distribution pole and visually inspects the overhead distribution line for flaw detection involves a risk of falling, electric shock or the like. Further, the visual work is a labor-intensive work, is not only inefficient, and lacks attention due to lack of attention, and thus lacks reliability. Further, since the deteriorated portion within the diameter of the overhead distribution line cannot be visually detected, it lacks reliability.

The second flaw detection method using eddy current is inconvenient because it cannot be performed when the overhead distribution line is a live line. Further, since the eddy current changes not only according to the defect portion but also according to the surface shape of the overhead wire, the irregularities on the surface of the twisted wire may be detected as a defect.

The third flaw detection method using X-rays has the advantages that the deterioration can be detected with high accuracy and that the deteriorated portion can be found regardless of the inside or outside diameter of the overhead distribution line. However, the X-ray apparatus is very expensive and there is a problem in economic efficiency. In addition, there is a problem that X-rays are harmful to the human body and cannot be used easily.

The fourth AE method can be carried out even when the overhead distribution line is a live line. Further, there is an advantage that a deteriorated portion can be found regardless of the inside and outside of the overhead distribution line, and it is an excellent nondestructive inspection method as compared with the method using the X-ray or the like.
However, the conventional AE method cannot always monitor the same place. It is necessary to transport the holder, vibrating rod, and analysis device to the site each time. Then, it is necessary to manually attach / detach the holder or forcibly vibrate with the vibrating rod.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and to provide a method for monitoring deterioration of an overhead distribution line which requires no human labor, can be inspected at any time, and can be remotely monitored.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is to install a communication cable in an overhead distribution line and to cause acoustic radiation generated in a deteriorated portion of the overhead distribution line in an insulator supporting the overhead distribution line. An acoustic sensor for detecting a noise and a transmission path for transmitting the output of the acoustic sensor are provided, the transmission path is connected to the communication cable, and deterioration of the overhead distribution line due to acoustic radiation is monitored through the communication cable. .

An anemometer may be provided near the overhead distribution line, and the output of the acoustic sensor may be transmitted to the transmission path when the anemometer detects a predetermined wind velocity or higher.

[0017]

With the above structure, when the overhead distribution line vibrates due to wind, acoustic radiation is generated at the deteriorated portion of the overhead distribution line. The acoustic radiation is transmitted to the acoustic sensor via the insulator, and the output of the acoustic sensor is transmitted to the communication cable via the transmission path.
The presence or absence of deterioration can be detected by analyzing the output of the acoustic sensor at one end of the communication cable with an analyzer. Since the output of the acoustic sensor can always be transmitted to the analysis device, deterioration can be detected when vibration occurs without forced vibration.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 shows a probe used in the method for monitoring deterioration of an overhead distribution line according to the present invention, and FIG. 3 is a sectional view thereof. The probe 1 mainly includes an AE sensor 2 that detects elastic waves generated in a deteriorated portion of an overhead distribution line,
The AE sensor 2 is built in and a holder 4 is attached to the insulator 3. The holder 4 is made of alumina or the like whose acoustic impedance substantially matches that of the insulator 3 in order to efficiently detect elastic waves from the overhead distribution line propagating to the insulator 3 supporting the overhead distribution line. The holder 4 includes an annular ring portion 5 fitted on the outer circumference of the insulator 3,
The holder part 4a is composed of a sensor part 6 in which an AE sensor is embedded, and the ring part 5 is integrated with the sensor part 6.
And the holder piece 4b on the opposite side is divided into two parts. As shown in the cross-sectional view, the holder pieces 4a and 4b each have a magnet 7 embedded in the surfaces that abut against each other, and are attachable to and detachable from the insulator 3 and retained by magnetic force after being attached to the insulator 3. It is configured to be.
The sensor portion 6 projects radially outward from the ring portion 5 and has a bottomed hole 8 from the tip thereof toward the ring portion 5 side.
Is provided. The AE sensor 2 consisting of an acoustic sensor is inserted into the bottom of the hole 8, and the AE sensor 2 is inserted from the outside of the hole 8.
A fixing bolt 9 for fixing the sensor 2 is screwed into a female screw formed in the hole 8 and inserted. The AE sensor 2 is accompanied by an E / O converter (not shown) that converts its output into an optical signal, and the optical fiber cable 10 is pulled out from the E / O converter to the outside of the probe.

In the method for monitoring deterioration of an overhead distribution line according to the present invention, the probe 1 is mounted on an insulator 3 which supports the overhead distribution line as shown in FIG. In FIG. 1, 11
Is a utility pole, and a horizontal arm 13 projecting at a right angle to the erection direction of the overhead distribution line 12 is provided above the utility pole, and a plurality of insulators 3 are erected on the arm 13 at intervals. Has been. Each insulator 3 has an overhead distribution line 1
2 is fixed. Also, the utility pole 11 has an arm 13
The communication cable 14 is fixed below. The communication cable 14 is installed in the same direction as the overhead distribution line 12.

The optical fiber cable 10 is pulled out from the probe 1 attached to each insulator 3, and the optical fiber cable 10 is extended along the electric pole 11 to extend the communication cable 1.
4 is retracted by a closure 15 provided on the upper part.
The optical fiber cable 10 is connected to the communication cable 14 in the closure 15. Although not shown, the communication cable 14 leads to a remote information management room, and an acoustic analysis device and the like are installed in the information management room. Above probe 1
The output signal of the AE sensor 2 inside is input to the acoustic analysis device in the distant information management room via the communication cable 14.

Under the above structure, the overhead distribution line 12
Is constantly monitored. When there is a deteriorated portion such as a crack in the wire in the overhead distribution line 12 due to vibration of the overhead distribution line 12 due to wind or the like, acoustic radiation is generated in the deteriorated portion.
The acoustic radiation propagates inside the overhead distribution line 12 and
Propagate to the insulator 3 which holds 2. Further, the acoustic radiation propagates to the probe 1 whose acoustic impedance matches that of the insulator 3 without attenuation, and the AE built in the probe 1
Propagate to the sensor 2.

The AE sensor 2 converts this acoustic signal into an electric signal, and the E / O converter converts this electric signal into an optical signal. This optical signal is transmitted to the closure 15 by the optical fiber cable 10, and is transmitted to the communication cable 14 in the closure 15. In the information management room, which is an extension of the communication cable 14, the acoustic emission signal is constantly monitored by the acoustic analysis device, so if the acoustic emission is a signal indicating deterioration of the overhead distribution line, immediately. Detected. It should be noted that FIG. 5 shows acoustic emission characteristics when the electric wire fatigue test is performed. It can be seen that the relationship between the time of fatigue and the cumulative energy of acoustic radiation changes greatly at the time when a crack occurs, and the energy of acoustic radiation rapidly increases as a crack enters the wire.
Therefore, it is also possible to prepare a database accumulating data as shown in FIG. 5 in the information management room and refer to this database to determine the deterioration from the acoustic emission analyzed above.

Next, another embodiment of the present invention will be described.

FIG. 4 shows a utility pole 11, an arm 13, an overhead distribution line 12, an insulator 3, a probe 1, and an optical fiber cable 10 similar to those in FIG. In this example, the arm 13
The anemometer 16 is attached to the, and the controller 17 connected to the anemometer 16 is attached to the electric pole. Anemometer 1
6 is a controller 17 which outputs an electric signal or an optical signal according to the wind speed.
Output to. The optical fiber cable 10 from the probe 1 is connected to the controller 17, and the cable 18 is provided from the controller 17 to the closure 15 on the communication cable 14. The controller 17 transmits the output of the acoustic sensor 2 from the probe 1 to the communication cable 14 when the anemometer 16 detects a predetermined wind speed or higher. By doing so, the inspection is automatically started when the overhead distribution line 12 vibrates due to the wind. Since the deterioration of the electric wire progresses when the electric wire is fatigued by the vibration due to the wind, the anemometer 1
If the detection of acoustic radiation is triggered by the detection signal of No. 6, it is possible to monitor the progress of deterioration at a good timing.

[0026]

The present invention exhibits the following excellent effects.

(1) Since it is constantly monitored, it is not necessary to perform periodic inspections frequently.

(2) Since forced vibration is unnecessary and remote monitoring is possible, it is not necessary for a person to go to the site,
Eliminates the hassle of transporting materials and securing personnel.

(3) Since the detection signals of a large number of electric poles can be collected via the communication cable, a large number of overhead distribution lines can be monitored at the same time.

(4) Since the probe is attached to the insulator, there is no risk of electric shock during attachment.

(5) The communication cable only needs to be installed near the target overhead distribution line, and the existing communication cable can be used, which is economical.

[Brief description of drawings]

FIG. 1 is a perspective view of a utility pole for explaining a method of the present invention.

FIG. 2 is a perspective view in which a probe used in the method of the present invention is mounted on an insulator.

3 is a cross-sectional view of the probe of FIG.

FIG. 4 is a perspective view of a utility pole showing another embodiment of the present invention.

FIG. 5 is a characteristic diagram showing the relationship between the time during which the electric wire is fatigued and the cumulative energy of acoustic radiation.

FIG. 6 is a perspective view of a utility pole showing a conventional flaw detection method by the AE method.

[Explanation of symbols]

 1 Probe 2 Acoustic Sensor (AE Sensor) 3 Insulator 12 Overhead Distribution Line 14 Communication Cable

Front Page Continuation (72) Inventor Koji Nagano 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Hitachi Power Systems Co., Ltd. (72) Inventor Hiroshi Kubokawa 5-1-1 Hidaka-cho, Ibaraki Prefecture No. 1 Inside Hitachi Cable's Power Systems Laboratory (72) Inventor Yasuhiro Kondo 5-1-1 Hidakacho, Hitachi City, Ibaraki Prefecture Hitachi Cable Co., Ltd. Hidaka Factory

Claims (2)

[Claims] 1. An acoustic sensor for detecting acoustic radiation generated in a deteriorated portion of an overhead distribution line, and a transmission for transmitting an output of the acoustic sensor, wherein a communication cable is provided along with the overhead distribution line, and an insulator supporting the overhead distribution line is provided. A method for monitoring deterioration of an overhead distribution line, comprising providing a path, connecting the transmission path to the communication cable, and monitoring the deterioration of the overhead distribution line due to acoustic radiation through the communication cable. 2. An anemometer is provided in the vicinity of the overhead distribution line, and the output of the acoustic sensor is transmitted to the transmission path when the anemometer detects a predetermined wind speed or higher. Item 1. A method for monitoring deterioration of an overhead distribution line according to Item 1.