JP3717341B2 - Defect detection method for overhead wire crimping part - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for detecting defects such as cracks, thinnings and breaks in an overhead wire crimping part using ultrasonic waves.
[0002]
[Prior art]
FIG. 6 shows a general installation state of an overhead wire. The overhead wire 1 is composed of an overhead power transmission line 2, an overhead ground wire 3, a jumper wire 4, and the like, and is used by being installed on support members such as a tension steel tower 5 and a suspension steel tower 6. For this reason, it is exposed to wind and causes vibrations or rainwater to invade, and for many years, metal fatigue and corrosion occur in the strands constituting the overhead wire. When this metal fatigue or corrosion progresses, the strands are cracked or thinned, and are broken (disconnected). When the strand breaks, the mechanical strength of the overhead wire is reduced and spreads to other strands, leading to the breakage of the overhead wire.
[0003]
To such an overhead wire, overhead wire parts such as a retention clamp 7, a jumper sleeve 8, a suspension clamp 9, an anti-vibration damper 10, a spacer, a conductor connection sleeve, and an overhead wire gripping metal fitting are crimped by compression or bolt tightening. In these crimped parts or in the vicinity thereof, defects such as cracks and breaks are likely to occur in the overhead wires.
[0004]
Conventionally, as a method of detecting a defect in the overhead wire crimping part, if there is a defect in the overhead wire crimping part, the electrical resistance of that part becomes high and the temperature rises due to heat generation. There are a method of measurement and a method of X-ray (a kind of ionizing radiation) irradiation.
[0005]
[Problems to be solved by the invention]
The above temperature measurement method is used when detecting defects in overhead wire crimping parts from the air using a helicopter, etc., but the temperature rise of the overhead wire occurs exclusively during energization and does not energize during inspection and does not increase in temperature. It is difficult to produce a temperature difference from the outside air temperature, and it is far away from the overhead wire crimping part to be inspected, and it is susceptible to disturbances such as climate and temperature changes. There was a problem that it was not possible to detect well and the reliability was poor. In addition, because of the indirect defect detection method of detecting a temperature rise, there is a problem that a confirmation investigation is necessary and the inspection becomes complicated. Further, when a helicopter is used, there is a problem that the equipment becomes large and the cost increases.
[0006]
Next, the method by X-ray irradiation can solve the problem of the method by temperature measurement, but the following new problem has occurred. That is, since X-rays are irradiated in the direction perpendicular to the overhead line, defects such as cracks, thinnings, breaks, etc. that frequently occur in the plane perpendicular to the strands cannot be detected with high accuracy, Because the camera is heavy, handling at high places is troublesome, and because the X-ray camera is large, there is a risk of interference with adjacent strands, and it is not easy to accurately detect the presence or absence of defects for each strand. Furthermore, there is a possibility that the X-ray camera may interfere with an adjacent overhead line, and the distance between the camera and the X-ray source cannot be taken, and even if there is a defect, it may not be possible to photograph this reliably. X-rays emitted from the radiation source affect the human body, so handling is necessary and skill is required, film replacement must be performed on a steel tower, workability is poor, Such as mountainous areas Must be done in the stool place, there has been a variety of problems such as time-consuming that in preparation.
[0007]
The present invention solves the above-described problems, can detect an overhead wire defect in the overhead wire crimping portion with high accuracy, and is easy to handle and easy to handle an apparatus used for detecting an overhead wire defect. It aims at providing the defect detection method of a wire crimping part.
[0008]
[Means for Solving the Problems]
In the overhead wire crimping part defect detection method according to the present invention, as a first means for solving the above-described problem, an overhead wire is inserted into a crimping sleeve of an overhead wire component, and the crimping sleeve is compressed or tightened. In the overhead wire crimping part formed by crimping the overhead wire to the crimping sleeve, an ultrasonic probe is applied to the outer surface of the overhead wire located outside the crimping sleeve in the longitudinal direction. When ultrasonic waves are transmitted while being tilted into the strands of the overhead wire and the reflected waves reflected from the defective portions of the strands are received , the ultrasonic probe is moved along the stranding direction of the strands. Then, by performing transmission / reception of ultrasonic waves, a defect of the overhead wire in the overhead wire crimping portion is detected.
[0009]
Further, as a second means for solving the above-described problem, the ultrasonic probe is transmitted while being inclined in the strand, and the reflected wave reflected from the defective portion of the strand is received. After that, the ultrasonic probe is moved along the strand twisting direction, and the ultrasonic wave is transmitted again from the ultrasonic probe while being tilted into the strand, and the reflected wave reflected from the defective portion of the strand. To detect the defect of the overhead wire crimping part by repeatedly transmitting and receiving ultrasonic waves and moving the ultrasonic probe as necessary, and comparing the received reflected waves with each other. It is a feature.
[0010]
Furthermore, as a third means for solving the above-described problem, the ultrasonic probe is moved while the ultrasonic wave is transmitted from the ultrasonic probe while being inclined into the element wire, so that a defective portion of the element wire is obtained. The defect of the overhead wire crimping part is detected by receiving the reflected wave reflected from the antenna.
[0011]
As described above, an ultrasonic probe is applied to the outer surface of the overhead wire located outside the longitudinal direction of the crimp sleeve of the overhead wire component, and the ultrasonic wave is transmitted from the ultrasonic probe into the strand of the overhead wire. By transmitting the tilt and receiving the reflected wave reflected from the defective part of the wire, the overhead wire defect in the overhead wire crimping part is detected, so from the end face of the wire constituting the overhead wire It is not necessary to detect the defect by transmitting the ultrasonic wave into the strand, and the defect of the overhead wire crimping portion can be directly detected in the vicinity thereof.
[0012]
In addition, in the case of X-rays, since this is irradiated in the direction perpendicular to the overhead wire (elementary wire), it is impossible to accurately detect cracks, thinnings, and breaks (disconnections) that frequently occur in the plane perpendicular to the element wire. On the other hand, in the case of ultrasonic waves, since this is transmitted in the longitudinal direction in the strand, not only the strand breaks, but also defects such as cracks and thinness that have not yet been broken. Can be detected, and maintenance and management of overhead lines can be performed efficiently.
[0013]
In addition, unlike an X-ray camera, the ultrasonic probe is small and light, so it is easy to handle in high places and there is no risk of interfering with adjacent strands. The presence or absence of a defect can be detected every time, and there is no possibility of interfering with an adjacent overhead line. Therefore, if there is a defect in an overhead line, this can be reliably and easily detected.
[0014]
In addition, since it does not adversely affect the human body, it is easy to handle, and it is not necessary to replace the photographed film at a high place such as an X-ray camera or to develop it on site. It is simple and hassle-free, and the defect detection operation can be performed efficiently.
[0015]
Further, by performing the transmission and reception of ultrasonic waves is moved along the ultrasonic probe in the twisting direction of the strand, and detects a defect of the overhead wire in an overhead wire crimping portion, the reflection from the defect portion of the wire It is possible to determine whether the reflected wave is caused by a defect of the strand or a disturbance (noise), and the S / N ratio for detecting the defect of the strand can be further increased.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram for explaining the principle of the present invention. In this figure, a defective portion S due to breakage (breakage) occurs in the strand 22a of the overhead wire 22 at a location that enters, for example, about 10 to 20 mm from the end of the crimp sleeve 20a made of an aluminum material of the overhead wire crimping portion 20. It shows the state. In order to detect the defect of the crimping portion 20, the ultrasonic probe 24 is brought into contact with the outer surface of the overhead wire 22 (element wire 22a) located on the outer side in the longitudinal direction from the end of the crimping sleeve 20a. At this time, in order to efficiently transmit an ultrasonic pulse signal from the ultrasonic probe into the strand 22a, the outer surface of the overhead wire 22 (strand 22a) in advance in the circumferential direction, for example, 100% of the contact medium. Glycerin is applied, and this is interposed between the overhead wire 22 (element wire 22 a) and the ultrasonic probe 24.
[0017]
Next, an ultrasonic pulse signal of about 0.2 to 5 MHz generated from a transmission unit 24a of the ultrasonic probe 24 by a crystal oscillator or the like is placed in the strand 22a and is perpendicular to the axis of the strand. An angle θ is inclined with respect to M, and transmission is performed in the direction of the crimping sleeve 20a. If the angle θ is smaller than 20 degrees, the detection sensitivity of the defect portion S becomes dull, and if it exceeds 80 degrees, ultrasonic waves cannot be efficiently transmitted into the strand 22a, so the range of 20 to 80 degrees is practical. The range of 40 to 60 degrees is preferable.
[0018]
The ultrasonic probe 24 is lightweight and small, and transmits ultrasonic waves for each strand 22a made of an aluminum material having a diameter of about several millimeters, and reflects reflected waves reflected from defective portions such as cracks, thinnings and breaks. The signal can be received by a receiving unit (not shown) in the ultrasonic probe 24. In this way, the ultrasonic probe is scanned manually for each strand in the circumferential direction of the overhead wire 22 or by a scanning jig (not shown), and the waveform and size of the received reflected wave ( (Amplitude) and the occurrence position are observed on a monitor.
[0019]
When no defects such as cracks, thinnings and breaks occur in the strands 22a, the ultrasonic waveform of the reflected wave is relatively flat as shown in FIG. Many appear. For example, when a defective portion S (a portion of distance p from the transmitting portion 24a of the ultrasonic probe 24) is present on the strand 22a, the reflected wave is superfluous at the defective portion S as shown in FIG. The sound waveform appears steep and large. Therefore, the presence / absence of a defect, the type of defect, and the progress of deterioration can be determined by comparing with the threshold values for the presence / absence of defects and the presence / absence of fracture obtained in advance through experiments and past data. 2A and 2B, the horizontal axis indicates the distance (mm) from the transmitting portion 24a of the ultrasonic probe 24 to the defective portion S, and the vertical axis indicates the case where the maximum amplitude is 100. The percentage (%) is shown.
[0020]
In the present invention, since the ultrasonic wave is transmitted from the ultrasonic probe 24 while being inclined into the strand 22a, if the defect portion S does not occur in the strand 22a, the reflected wave is present in the ultrasonic probe 24. Reflected and transmitted in a direction different from the direction, the return of the reflected wave is delayed. On the other hand, when the defect portion S occurs in the strand 22a, the reflected wave is reflected toward the ultrasonic probe 24 at the defect portion S, and the larger the defect portion, the more the reflection amount, and the reflection. Since the attenuation of the wave is reduced, as described in the section for solving the problem, the defect of the strand 22a can be accurately detected. Treatment such as repairing or replacing the crimping portion 20 can be performed accurately and promptly.
[0021]
In the present invention, the defect detection of the overhead wire crimping portion 20 is not limited to being performed for each strand 22a. For example, in a place where the deterioration state is small, in order to increase the work efficiency, it may be performed for each of a plurality of strands, and when the existence of a defect is suspected in this inspection, it may be switched to the detection of each defect It is.
[0022]
Next, regarding the defect detection method of the present invention, a method for transmitting and receiving ultrasonic waves is shown in FIGS. In the first method, after the ultrasonic wave is inclined from the ultrasonic probe 24 into the strand 22a and transmitted in the direction of the crimping sleeve 20a, and the reflected wave reflected from the defective portion of the strand is received, As shown in FIG. 3 (b), the ultrasonic probe 24 is moved in the direction of the arrow by a distance q, for example, along the twisting direction of the strand 22a, and the ultrasonic probe 24 again transmits the ultrasonic wave from the ultrasonic probe 24. Inclined into the wire 22a and transmitted in the direction of the crimping sleeve 20a, received the reflected wave reflected from the defective portion of the wire 22a, and transmitted / received ultrasonic waves and moved the ultrasonic probe 24 as necessary. Is repeated, and a plurality of received reflected waves are compared with each other, thereby detecting a defect in the overhead wire crimping portion 20.
[0023]
According to such a method, when the ultrasonic waveform of the reflected wave is due to the presence of a defect in the strand 22a, the waveform position of the reflected wave moves to the right by the distance q as shown in FIG. On the other hand, when the ultrasonic waveform of the reflected wave is not due to the presence of a defect in the strand 22a but due to disturbance (noise), the position of the ultrasonic waveform of the reflected wave hardly moves. Therefore, by observing whether or not the position of the ultrasonic wave of the obtained reflected wave moves in the lateral direction when the ultrasonic probe 24 is moved, is this reflected wave caused by a defect in the strands? Therefore, it is possible to more accurately determine whether the disturbance is caused by noise (noise), and it is possible to increase the S / N ratio of defect detection of the overhead wire crimping portion 20, which is preferable.
[0024]
In the second method, the ultrasonic probe 24 is transmitted in the direction of the crimping sleeve 20a while inclining the ultrasonic wave from the ultrasonic probe 24 into the strand 22a, and the ultrasonic probe 24 is moved along the twisting direction of the strand 22a. In this method, for example, the distance q is moved in the direction of the arrow, or the distance q is reciprocated, and the reflected wave reflected from the defective portion of the strand 22a is received to detect the defect in the overhead wire crimping portion. . This method includes a case where the ultrasonic probe 24 is moved first and transmission of ultrasonic waves is started. Even in this method, when the ultrasonic wave waveform of the received reflected wave is due to the presence of a defect in the strand 22a, it moves to the right by the distance q or reciprocates to the left and right. If there is no defect and it is due to disturbance (noise), it will not move, so as described above, whether the reflected wave is caused by a defect in the wire, whether or not the reflected wave has moved. Can be determined.
[0025]
Next, an example in which the present invention is applied to detection of a defect in each crimping portion of a holding clamp and a jumper sleeve of an overhead power transmission line which is an overhead wire component will be described with reference to FIG. The overhead wire crimping portion 25 of the retaining clamp has a steel core portion 28a exposed for a predetermined length of an overhead power transmission line 28 made of a steel core aluminum stranded wire in a steel sleeve 27 inserted into a retaining clamp body 26 made of an aluminum material. Then, the entire outer periphery of the compression connection portion between the steel sleeve 27 and the steel core portion 28a and the outer periphery of the overhead power transmission line 28 in the vicinity thereof are covered with a crimp sleeve 29 made of an aluminum material. It is configured by compressing the sleeve 29 and crimping the overhead power transmission line 28 to the retention clamp body 26. In this overhead wire crimping portion 25, when the crimping sleeve 29 is compressed in order to attach the retention clamp to the overhead power transmission line 28, or after the power transmission line is installed on the steel tower, the overhead power transmission line 28 is subjected to metal fatigue. Or corrosion may occur, and the overhead power transmission line 28 may be cracked, thinned, broken, or the like.
[0026]
When inspecting the presence or absence of such a defect in the crimping portion 25, for example, an overhead power transmission line located outside the longitudinal direction of the crimping sleeve 29 of the overhead wire crimping portion 25 in a place where inspection on the ground or on a steel tower is required. The ultrasonic probe 24 is applied to the outer surface 28 for each of the outermost strands 28b, and ultrasonic waves are inclined from the ultrasonic probe into the strand 28b and transmitted in the direction of the crimping sleeve 29. When receiving the reflected wave reflected from the defective portion of the strand 28b, the ultrasonic probe 24 is moved along the twisting direction of the strand 28b to transmit / receive the ultrasonic wave, and inspect for the presence or absence of the defect. Such an operation method is repeated for each strand 28 b along the circumferential direction of the overhead power transmission line 28.
[0027]
The overhead wire crimping portion 30 of the jumper sleeve is formed of an aluminum twisted wire in a crimp sleeve 32a formed at the tip of a jumper sleeve 32 made of an aluminum material fastened to the tension clamp body 26 with a bolt 31, as shown in FIG. The jumper wire 33 is inserted, the crimp sleeve 32 a is compressed, and is crimped to the jumper sleeve 32.
[0028]
Even when detecting a defect in the overhead wire crimping portion 30, the ultrasonic probe 24 is applied to the outer surface of the jumper wire 33 positioned on the outer side in the longitudinal direction of the crimping sleeve 32a for each of the outermost strands 33a. When the ultrasonic wave is inclined from the ultrasonic probe 24 into the wire 33a and transmitted in the direction of the crimping sleeve 32a and the reflected wave reflected from the defective portion of the wire 33a of the jumper wire 33 is received , The ultrasonic probe 24 is moved along the stranding direction of the strand 33a to transmit / receive ultrasonic waves ,
Perform defect detection. Others are the same as the case of detecting between the defects of the overhead wire crimping portion 25 of the retaining clamp, and the description thereof is omitted.
[0029]
The overhead wire crimping part is not limited to the above-mentioned retention clamp or jumper sleeve, but aerial wire parts other than the above, for example, vibration prevention dampers, spacers, conductor connection sleeves, conductor terminals, etc. It is also applied to the wire crimping part. Further, the crimping portion is not limited to the one by compression, but includes one that clamps to the overhead power transmission line by bolt tightening as in the case of a suspension clamp. In addition to overhead power transmission lines, overhead lines include overhead lines such as overhead ground lines and jumper lines.
[0030]
Furthermore, in the above-described embodiment of the invention, the case where ultrasonic waves are transmitted from the ultrasonic probe into the strand toward the crimp sleeve has been described. However, the defective portion of the strand is generated only in the crimp sleeve. It does not necessarily occur, and it may also occur at the outer portion of the crimp sleeve. In this case, the ultrasonic probe may be slightly separated from the crimping sleeve, and the ultrasonic wave may be transmitted toward the crimping sleeve. However, the ultrasonic wave may be transmitted in the direction opposite to the crimping sleeve. In this case, the ultrasonic probe is not moved and it is only necessary to reverse 180 degrees at the same position, which is effective for detecting a defect of a strand in a narrow place or region. Furthermore, if the transmission part built in the ultrasonic probe is inverted 180 degrees, or if a transmission part that can transmit ultrasonic waves in the direction opposite to the crimping sleeve is newly installed, There is no need to move and flip the probe, which is more effective.
[0031]
【The invention's effect】
According to the present invention, as described above, in the overhead wire crimping portion formed by inserting the overhead wire into the crimp sleeve of the overhead wire component and compressing or fastening the crimp sleeve, the overhead wire is crimped to the crimp sleeve. The ultrasonic probe is applied to the outer surface of the overhead wire located outside the longitudinal direction of the crimping sleeve, and the ultrasonic wave is inclined from the ultrasonic probe into the wire constituting the overhead wire and transmitted. By detecting the reflected wave reflected from the defective portion of the strand, the defect of the overhead wire in the overhead wire crimping portion is detected, so that the ultrasonic wave is transmitted from the end surface of the strand constituting the overhead wire. It is no longer necessary to detect the defect by sending it in, and the defect of the overhead wire crimping portion can be directly detected in the vicinity thereof.
[0032]
In addition, in the case of X-rays, since this is irradiated in the direction perpendicular to the overhead wire (elementary wire), it is impossible to accurately detect cracks, thinnings, and breaks (disconnections) that frequently occur in the plane perpendicular to the element wire. On the other hand, in the case of ultrasonic waves, since this is transmitted in the longitudinal direction in the strand, not only the strand breaks, but also defects such as cracks and thinness that have not yet been broken. Can be detected, and maintenance and management of overhead lines can be performed efficiently.
[0033]
In addition, unlike an X-ray camera, the ultrasonic probe is small and light, so it is easy to handle in high places and there is no risk of interfering with adjacent strands. The presence or absence of a defect can be detected every time, and there is no possibility of interfering with an adjacent overhead line. Therefore, if there is a defect in the overhead line, this can be reliably and easily detected.
[0034]
In addition, since the defect detection method using ultrasonic waves does not adversely affect the human body, it is easy to handle, and it is necessary to replace the photographed film at a high place, such as an X-ray camera, or develop it on site. Therefore, the operation of the apparatus is simple and time-consuming, and the defect detection work can be performed efficiently.
[0035]
In addition, after transmitting the ultrasonic wave from the ultrasonic probe while tilting it into the strand and receiving the reflected wave from the defective portion of the strand, the ultrasonic probe is moved along the twist direction of the strand. Move the ultrasonic probe again from the ultrasonic probe, tilt it into the strand, and transmit the reflected wave reflected from the defective part of the strand. The defect of the overhead wire crimping part is detected by transmitting and receiving ultrasonic waves along the line, so whether the reflected wave reflected from the defective part of the strand is due to the defect of the strand ( It is possible to determine whether it is due to noise), and the S / N ratio for detecting a defect of the wire can be further increased.
[Brief description of the drawings]
FIG. 1 is a front view for explaining an outline of the present invention.
FIG. 2 is an ultrasonic waveform diagram showing a detection state of a defective portion of an overhead wire crimping portion according to the present invention, where (A) shows a state where no defective portion is detected, and (B) shows a detected defective portion. It is a figure of a state.
FIGS. 3A and 3B are plan views for explaining a method for transmitting and receiving ultrasonic waves according to the defect detection method of the present invention. FIG. 3A is a view before moving an ultrasonic probe, and FIG. It is a figure after moving an acoustic probe.
FIG. 4 is a diagram showing an ultrasonic waveform state of a reflected wave obtained when an ultrasonic probe is moved.
FIG. 5 is a schematic diagram showing a state in which a defect is detected in each crimping portion of an aerial transmission line retention clamp and jumper sleeve.
FIG. 6 is a schematic view showing a general overhead line installation state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 Overhead wire crimping part 20a Crimp sleeve 22 Overhead wire 24 Ultrasonic probe 24a Transmission part 25 Overhead wire crimping part of a tension clamp 26 Tension clamp main body 27 Steel sleeve 28 Overhead power transmission line 28a Steel core part 28b Wire 29 Crimp sleeve 30 Overhead wire crimping part 31 Bolt 32 Jumper sleeve 32a Crimping sleeve 33 Jumper wire 33a Wire S S Defective part

Claims (3)

An overhead wire is inserted into the crimp sleeve of the overhead wire component, and the crimp sleeve is compressed or tightened, so that the overhead wire is crimped to the crimp sleeve. The ultrasonic probe is applied to the outer surface of the overhead wire to be transmitted, and the ultrasonic wave is transmitted from the ultrasonic probe while being tilted into the strand constituting the overhead wire, and reflected from the defective portion of the strand. An aerial feature characterized in that when receiving a wave, an ultrasonic probe is moved along the stranding direction of the strand to transmit and receive an ultrasonic wave, thereby detecting an overhead wire defect in the overhead wire crimping portion. Defect detection method for wire crimping part. After the ultrasonic wave is transmitted from the ultrasonic probe to be inclined in the strand and the reflected wave reflected from the defective portion of the strand is received, the ultrasonic probe is moved along the twist direction of the strand. Then, the ultrasonic wave is transmitted again from the ultrasonic probe so that it is tilted into the strand, and the reflected wave reflected from the defective portion of the strand is received. The defect detection method for an overhead wire crimping part according to claim 1, wherein the defect of the overhead wire crimping part is detected by repeatedly moving the touch element and comparing a plurality of received reflected waves with each other. . By transmitting the ultrasonic wave from the ultrasonic probe while tilting it into the strand, moving the ultrasonic probe and receiving the reflected wave reflected from the defective portion of the strand, The defect detection method for an overhead wire crimping part according to claim 1, wherein a defect of the crimping part is detected.

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