JPH04190174A - Device for detecting damage to strand - Google Patents

Abstract

PURPOSE:To detect a crack and a break of a strand highly precisely by evaluating energy on the basis of noise generated at the time of vibration and by detecting a damage therefrom. CONSTITUTION:An aerial distribution line is held and vibration of a prescribed frequency is impressed thereon by a vibration generating device. When a crack occurs in a strand constructing a conductor herein, an acoustic emission is generated in the crack and in the vicinity thereof by the vibration and it is detected by a piezoelectric element 20. As to a signal subjected to envelope detection in an envelope detecting circuit 24, a waveform area (energy) for each one second of the envelope detection signal exceeding a threshold signal outputted by a threshold setting circuit 26 is computed in an energy computing circuit 25. Subsequently, the envelope detection signal and the threshold signal are compared with each other by a comparator 28, and when the envelope detection signal is larger than the threshold signal, a high-level signal is outputted to a hit number counting circuit 29, whereby the number of hits for each one second is counted. In a recording-determining element 30, the energy and the number of hits are evaluated and the state of the damage of the strand is determined and displayed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is directed to a linear body for detecting damage to a linear body constructed by twisting strands of wire, such as an overhead power transmission/distribution line or an overhead ground wire. This invention relates to a wire damage detection device.

(Prior art) Overhead power transmission lines and distribution lines vibrate due to external loads such as wind, ice, and snow, and stress due to vibration tends to concentrate on parts supported by discharge clamps, etc., and this stress concentration causes the strands to deteriorate. Cracks may occur or wires may break.

Conventionally, detection of cracks and breaks in strands has been done by
Relying on visual inspection by workers. (Problem to be solved by the invention) However, in the visual inspection by a worker, ■ Although it is possible to inspect the outer layer of the conductor for cracks or broken wires, it is difficult to inspect the inner layer for cracks or broken wires. I can't.

■In order to inspect the part supported by a support such as a discharge clamp for cracks or broken wires, it is necessary to remove and attach the support.

■High test accuracy cannot be obtained due to individual differences among workers and the work environment.

There were some problems.

Therefore, the present invention has been made to solve these problems, and is a method for detecting damage to the strands of a linear body, which can detect the damage state of the strands with high accuracy while supporting the linear body. The purpose is to provide equipment.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the strand damage detection device for a linear body of the present invention includes an acoustic detection method that detects the sound generated in the linear body when the linear body vibrates. and a signal processing means for processing the signal outputted by the acoustic detection means, and detects damage to the wire based on the signal outputted by the signal processing means.

Note that in this specification, sound includes not only acoustic emission generated in the wires but also sound caused by sliding contact between wires.

(Function) In the strand damage detection device for a linear body of the present invention, when the linear body generates sound due to vibration, the sound detection means detects this sound and outputs this detection signal to the signal processing means.

The signal processing means processes this detection signal and outputs a signal used for damage determination.

Then, damage to the wire is detected based on the output signal of the signal processing means.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described based on the accompanying drawings.

FIG. 1 is a configuration diagram showing the electrical configuration of the wire damage detection device for a linear body according to this embodiment, FIG. FIG. 3 is a diagram showing signal waveforms at various parts of the wire damage detection device for a linear body according to this embodiment.

First, the electrical configuration of a wire damage detection device for a linear body will be explained based on FIG.

In FIG. 1, reference numeral 20 denotes a piezoelectric element that is attached to the surface of a conductor of an overhead distribution line, which will be described later, and detects sound generated in the conductor when the overhead distribution line vibrates, and the output signal of this piezoelectric element 20 is is amplified by a preamplifier 21 and then sent to a bandpass filter 22 to remove noise components.

The signal from which noise components have been removed by the bandpass filter 22 is amplified by the main amplifier 23 and then sent to the envelope detection circuit 2.
4 and whose envelope has been detected by the envelope detection circuit 24 is sent to the energy calculation circuit 25.

Reference numeral 26 denotes a threshold setting circuit for setting a threshold, and a threshold signal output from this threshold setting circuit 26 is sent to the energy calculation circuit 25 and a comparator described later. .

The energy calculation circuit 25 has a function of calculating the waveform area (energy) for each predetermined time (for example, 1 second) of the envelope detection signal exceeding the threshold signal, and the output signal of the energy calculation circuit 25 is , is sent to the recording determination section 30.

Preamplifier 21, bandpass filter 22, main amplifier 23, envelope detection circuit 24, energy calculation circuit 25
and the energy analysis processing circuit 2 with the threshold setting circuit 26.
7 are made up.

Note that energy analysis refers to determining energy from the acoustic signal detected by the piezoelectric element 20 and evaluating this energy to determine damage to the wire.

Moreover, the signal whose envelope was detected by the envelope detection circuit 24 is
It is also sent to comparator 28.

This comparator 28 compares the signal detected by the envelope detection circuit 24 with the threshold signal outputted from the threshold setting circuit 26, and the envelope detection signal exceeds the threshold signal. A high level signal is sent to the hit number counting circuit 29 when the hit count is in progress.

This hit number counting circuit 29 has a function of counting the number of pulses (hit number) of the pulse signal outputted by the comparator 28 every predetermined time (for example, 1 second), and the output signal of this hit number counting circuit 29 is , is sent to the recording determination section 30.

Preamplifier 21, bandpass filter 22, main amplifier 23, envelope detection circuit 24, threshold setting circuit 26,
The comparator 28 and the hit number counting circuit 29 constitute a hit number analysis processing circuit 31. Furthermore, what is human count analysis?
Determine the number of hits from the acoustic signal detected by the piezoelectric element 20,
The number of hits is evaluated to determine damage to the wire.

The recording determination unit 30 records the energy and the number of hits, evaluates the energy and the number of hits, and displays the determination result such as the presence or absence of damage.

Next, the operation of the strand damage detection device for a linear body will be explained based on FIGS. 2 and 3.

In FIG. 2, numeral 1 indicates an overhead power distribution line,
The insulating layer of the overhead power distribution line 1 supported by the discharge clamp 2 has been removed to expose the conductor IA.

This conductor IA is partially supported by the recess of the insulator 3,
It is fixed with a presser fitting 5 inserted through the port 4 and a nut 6 screwed onto the bolt 4. In addition, the code|symbol 7 has shown the utility pole which supports the discharge clamp 2.

A piezoelectric element 2 is placed on the surface of the conductor IA near the discharge clamp 2.
0 is fixed with insulating tape (not shown) or the like. Note that in order to improve the adhesion between the piezoelectric element 20 and the surface of the conductor IA, it is desirable to apply an inclusion such as silicone oil to the surface of the conductor IA.

Further, in FIG. 2, reference numeral 10 indicates a vibration device for applying vibration to the overhead power distribution line 1, and this vibration device 10 includes a case 11 that houses a drive mechanism such as a motor, and a case 11 that houses a drive mechanism such as a motor. It is comprised of a rod 12 that moves forward and backward by a drive mechanism, and a grip part 13 that is provided at the tip of the rod 12 and grips the overhead power distribution line 1. The position where the overhead power distribution line 1 is held by the gripping part 13 is preferably about 2 m away from the discharge clamp 2, and the amplitude at this position is preferably about 10 cm.

First, the above-mentioned grip part 13 grips the overhead power distribution line 1 and drives the vibrating device 1o, vibrates the grip part 13 via the rod 12, and vibrates the overhead power distribution line 1 at a predetermined frequency (1 to several Hz). Apply.

When a crack occurs in the wire constituting the conductor IA, acoustic emissions are generated in the crack and its vicinity due to vibration, and this acoustic emission propagates through the conductor IA and is detected by the piezoelectric element 20.

In addition, if a wire strand that constitutes the conductor IA is broken, the end faces of the broken wire may come into sliding contact with each other due to vibration, or the end of the broken wire may touch other surrounding wires. The sliding contact generates sound, which also propagates through the conductor IA and is detected by the piezoelectric element 20.

If a crack or a wire breakage occurs in the wire constituting the conductor 1A, the output signal of the piezoelectric element 20 will be, for example, as shown in FIG. 3 (a).
), and the envelope detection circuit 24
The signal after envelope detection has a waveform as shown in FIG. 3(b).

On the other hand, if no cracks or wire breaks occur in the wires constituting the conductor IA, the output signal of the piezoelectric element 20 has a waveform as shown in FIG. 3(C), for example. This shows that the noise signal has a small waveform area.

Next, in the energy calculation circuit 25, as shown in FIG.
As shown in d), the waveform area (the energy indicated by the hatched area in the figure) per second of the envelope detection signal exceeding the threshold signal is calculated.

Further, in the comparator 28, the envelope detection signal and the threshold signal are compared, and as shown in FIGS.
As shown in , when the envelope detection signal is larger than the threshold signal, a high level signal is output to the hit number counting circuit 29, and this hit number counting circuit 29 calculates the number of pulses (number of hits) per second. will be counted.

Then, in the recording determination section 30, as shown in FIGS. 4(a) and 4(b), the energy and the number of hits are output, and the energy and the number of hits are evaluated to determine whether the wire constituting the conductor IA is The state of damage is determined, and the determination results are displayed, such as "No damage,""Smalldamage,""Mediumdamage,""Largedamage," etc.

Incidentally, the energy and the number of hits may be digitally output as bar graphs every second, as shown in FIGS. 5(a) and 5(b).

Further, the damage state of the wire may be determined by a worker based on the energy and the number of hits.

The damage state of the wire may be determined by evaluating both the energy output from the energy analysis processing circuit 27 and the number of hits output from the hit number analysis processing circuit 31 as described above. The number of hits may be evaluated individually and the respective determination results may be displayed.

Further, either the energy analysis processing circuit 27 or the number of hits analysis processing circuit 31 may be used to evaluate the energy or the number of hits, and the determination result may be displayed.

FIG. 6 is a configuration diagram showing the electrical configuration of a wire damage detection device according to a modification of the present invention. In this wire damage device, a transmitter 39 is connected to the output side of the main amplifier 23, and a receiver 40 is connected to the signal processing section 41. Signal processing section 41
are the above-mentioned envelope detection circuit 24 and energy calculation circuit 2.
5, a threshold setting circuit 26, a comparator 28, and a hit count circuit 29. In the detection device of this modification, the detection signal of the piezoelectric element 20 can be transmitted by the transmitter 39 from the overhead power distribution line l side and received by the receiver 40 on the ground side. Even in a live wire state, the damage state of the conductor IA can be determined, and the determination work can be performed safely.

In the modification shown in FIG. 6, an optical transmitting module may be provided in place of the transmitter 39, and an optical receiving module may be provided in place of the receiver 40, and both modules may be connected by an optical fiber cable. Even if the overhead power distribution line 1 is live, the determination work can be performed safely.

FIG. 7 is a configuration diagram showing the electrical configuration of a wire damage detection device according to another embodiment of the present invention, and FIG. 8 is a schematic diagram showing the mounting state of a piezoelectric element in the same device.

First, in FIG. 8, U, V, and W indicate overhead distribution lines that constitute a three-phase distribution line, and piezoelectric elements 20U, 20V, and 20W are placed on the exposed conductors of each overhead distribution line, respectively. installed.

On the other hand, in FIG. 7, each piezoelectric element 20U.

20V and 20W are the energy analysis processing circuit 27 mentioned above.
are connected to each. Each energy analysis processing circuit 27 is connected to a recording determination section 30.

Next, the operation of the wire damage detection device of this embodiment will be explained.

First, when a vibration of 1 to several Hz is applied to the overhead distribution lines U, V, and W of each phase using the vibrating device shown in Fig. 2, the acoustic emissions generated from the conductors of each overhead distribution line and the sliding of the wires together are caused. The sound caused by contact with each piezoelectric element 20U,
Detected at 20V and 20W.

The output signals of each piezoelectric element 20U, 20V, and 20W are sent to an energy analysis processing circuit 27, respectively. Each energy analysis processing circuit 27 calculates, for example, the waveform area (energy) per second of the envelope detection signal exceeding the threshold signal in the same manner as described above (see FIG. 3(d)).

The recording determination unit 30 compares the respective energies taken in from the respective energy analysis processing circuits 27, and if these energies (waveform areas) are almost the same, the three-phase overhead distribution line U
, V, and W are determined to have no damage.

On the other hand, if one of the energies is large, for example, the energy obtained from the overhead distribution line U is transferred to the overhead distribution line V.
If the energy is larger than the energy obtained from the above and W, the recording determination unit 30 determines that a wire breakage or crack has occurred in the strands of the overhead power distribution line U. Then, as described above, the energy is evaluated and the damage state of the wire is displayed.

In the embodiments shown in FIGS. 7 and 8, a hit number analysis processing circuit 31 may be used instead of the energy analysis processing circuit 27.

Further, other signal processing circuits may be used to determine the difference in detection signals, and in short, the three-phase overhead power distribution line U,
It is only necessary to determine whether there is a difference between the detection signals from V and W.

Next, an example of the results of detecting strand damage by the apparatus of the above embodiment will be explained.

Three types of coated insulated wires with different damage conditions were set in a discharge clamp installed over a 20m span, and the tension was 400kg.
It was constructed in The voltage class of this coated insulated wire is 660.
At 0V, the cross-sectional area of the conductor is 240mm'', and the conductor consists of one central strand, 6 strands in the inner layer, and 12 strands in the outer layer.
Consists of books.

Then, 100 vibrations with a frequency of 3.0 Hz and an amplitude of 85 mm were applied to a position 2 m from the discharge clamp of each coated insulated wire.
The energy (per second) and the number of hits (
(every second) was recorded. The results are shown in Table 1 and Figure 9 (a).
, shown in (b).

Table 1 As a result, if cracks occur in some of the wires in the inner layer, a significant difference from the original can be recognized, and if the device of this example is used, the damaged state of the wires can be detected with high accuracy. It was confirmed that it can be done.

In this embodiment, a device for detecting damage to the strands of a linear body is illustrated as having both an energy analysis processing circuit 27 and a hit number analysis processing circuit 31. The damage detection device can also be configured with either of these two signal processing circuits. Further, the signal processing circuit is not limited to the above two signal processing circuits.

Furthermore, in this embodiment, vibration is applied to the overhead power distribution line 1 by the vibrating device 10, thereby actively generating sound in the conductor to detect damage to the wire.
It is also possible to permanently install the piezoelectric element 20 on the overhead power distribution line l and to detect sound generated by vibrations caused by wind or ice and snow without using the vibration device 10.

Further, although this embodiment exemplifies the detection of wire damage near the discharge clamp of an overhead power distribution line, the detection of damage is not limited to the vicinity of the discharge clamp, and the wire The body strand damage detection device can also be used to detect strand damage in overhead power transmission lines, overhead ground wires, wire lobes, etc., and the scope of its use is arbitrary.

(Effects of the Invention) As explained above, according to the present invention, damage to the wire is detected based on the sound generated in the wire when the wire vibrates. Cracks and breaks in the wires in the inner and outer layers can be detected with high accuracy without the need for attachment and detachment.

Further, according to the present invention, damage to the wires of overhead power transmission lines and distribution lines can be detected in a live state, so it is possible to provide a wire damage detection device that is extremely useful in practice.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the electrical configuration of the strand damage detection device according to the present invention, Fig. 2 is a block diagram showing the installation state of the overhead power distribution line in the discharge clamp section, and Figs. 3 (a) to 3). (f
) is a diagram showing output signal waveforms at each part of the device in FIG. 1, and FIG. 4(a). (b) is a diagram showing output waveforms of energy and number of hits, respectively; FIGS. 5(a) and (b) are bar graphs showing energy and number of hits, respectively; FIG. 6 is a configuration diagram according to a modification of the present invention; FIG. 7 is a block diagram showing the electrical configuration of a wire damage detection device according to another embodiment of the present invention, FIG. 8 is a schematic diagram showing the mounting state of the piezoelectric element in the device of FIG. 7, and FIG.
Figures (a) and (b) are diagrams showing the recording results of energy and number of hits, respectively. 1---------One overhead distribution line, IA--One conductor, 20, 20U, 20V, 20W-Piezoelectric element, 24-
1------Envelope detection circuit, 25---------
−1 energy calculation circuit, 26 −−−−−−−−L threshold setting circuit, energy analysis processing circuit, 28 −−−−−−−− comparator, 29 −−−−−−−−− Hit number counting circuit, 30---
-----11 Record determination section, 31---Number of hits analysis processing circuit. 211-711 Agent Patent Attorney Yukio Sato (and 1 other person) (a) Figure 4 (b) (c) Figure 3 (Part 1) Figure 3 (Part 2) (a) (b) Figure 5 Figure 7 Figure 8

Claims (3)

[Claims] (1) A wire damage detection device for a wire body formed by twisting wires, comprising: an acoustic detection means for detecting sound generated in the wire body when the wire body vibrates; , signal processing means for processing the signal output by the acoustic detection means, and detecting damage to the wire based on the signal output by the signal processing means. Detection device. (2) The signal processing means is characterized by comprising a detection means for envelope-detecting the signal output by the acoustic detection means, and an integration means for integrating the waveform area of the signal output by the detection means. A wire damage detection device for a linear body according to claim (1). (3) The signal processing means includes a detection means for envelope-detecting the signal output from the acoustic detection means, a comparison means for comparing the signal output from the detection means with a threshold signal, and an output from the comparison means. 2. The device for detecting strand damage in a linear body according to claim 1, further comprising a counting means for counting the number of pulses of the signal.