JPH102927A - Method and device for detecting breakage of cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify the broken part of a cable accurately with a transmitting and receiving type detector without the effect of the induction and noises in duced from a cable laying environment. SOLUTION: This device has a first oscillator 1, which outputs a signal X having a specified frequency, and a second oscillator 2, which outputs a signal Y having a specified frequency different from the signal X. Furthermore, a detector 3, which identifies the signals X and Y, oscillated in a cable 50 by the first and second oscillator 1 and 2, without contact, is provided. Then, the propagation of the signals X and Y from both end parts 51 and 53 of the cable 50 to a damaged part 55 is utilized, and the changing points of the signals on the cable 50 are detected. Thus, the changing points are specified as the damaged part 55. The signals X and Y form the non-sinusoidal waveforms, respectively. Thus, even when the place, where the brakage detection of the cable 50 is in the environment affected by 50-Hertz and 60-Hertz based noise sources of the commercial frequency, the detection of the signals X and Y can be performed accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a broken portion of a cable shielding layer or a core wire.

[0002]

2. Description of the Related Art For example, low-voltage and high-voltage cables for power transmission in factories are provided with copper tape or aluminum inside a sheath in order to avoid adverse effects due to induction of electrostatic induction, electromagnetic induction, etc. between adjacent cables. A shielding layer such as a tape may be provided. However, conventionally, when the shielding layer is damaged such as a disconnection, it is extremely troublesome to specify the damaged portion. In the method of specifying the damaged portion, first, the intermediate joint portion, the terminal processing portion, and the like are predicted as disconnection portions, and these portions are disassembled and the inside is inspected. Next, cut at the middle part of the cable laying length,
The operation of further dividing the half of the cable in which the disconnection is detected into half is repeated to narrow the disconnection location.
Then, twisting, biting, load, poor construction and the like are found by visual inspection or palpation of the cable, and the portion is dismantled. Thus, irrational work has been forced, for example, it is necessary to repeatedly uselessly disconnect and reconnect the cable, or it requires the skill and intuition of the operator.

Therefore, recently, dual frequencies (625 Hz and 87 Hz) were used.
5 Hertz) A transmission / reception type probe equipped with a transmitter for transmitting a signal and a receiver for receiving a signal via a cable has been developed, and some of the exploration devices have been put to practical use (for example, Toenec Corporation). Published "TOENEC News", June 1995 issue).

[0004]

By the way, taking the cable laying environment in a factory as an example, various inductions such as an inverter, a thyristor, a high frequency system, and a communication system including a commercial frequency of 50 Hz and 60 Hz are available. There is a noise source, and unless sufficient measures are taken against the induction and noise induced from the noise source, the above-described transmission / reception method cannot be searched. For this reason, the Toenec exploration device uses a special filter to eliminate the guidance disturbance.However, this measure is still not enough, especially when the location or environment changes, the detection results However, there was a risk that reliability might be lost due to the influence of induction and noise.
Therefore, it has been desired to provide a means for identifying a broken cable portion to overcome this problem. The above-mentioned problem is directly applicable even when the core of the cable is broken.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to accurately perform cable transmission and reception without being affected by induction or noise induced from a cable installation environment. It is possible to identify a damaged portion, and to improve the reliability of the device.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, a cable damage detecting method according to the present invention oscillates signals of different frequencies from both ends of a cable having a broken portion and propagates the signal through the cable. The signals having different frequencies are identified in a non-contact state, and the damaged portion is identified from the identification result.

When the cable is normal, signals oscillated and propagated from both ends of the cable are detected in the propagation range of the signals of both frequencies. Also,
If there is a break in the cable, the signal of each frequency is propagated from both ends of the cable to this break, so the signal change point is detected by identifying this signal in a non-contact state, and the cable change point is detected. Without breaking the signal, the change point of the signal is specified as a broken point.

In the present invention, it is preferable that the signals having different frequencies are distinguished from each other by at least one of a difference between waveforms or amplitudes of both signals. As a result, the two signals can be easily and accurately identified.

Further, it is preferable that each of the signals has a non-sinusoidal waveform. As a result, the locations where cable damage is detected include commercial frequency 50 Hz and 60 Hz systems,
Even in an environment affected by various sources of induction and noise such as inverters, thyristors, high-frequency systems, and communication systems, the signal waveform is different from these noises. Can be performed.

According to another aspect of the present invention, there is provided a cable breakage detecting device for outputting a signal having a specific frequency, and a signal having a specific frequency different from the first oscillator. And a detector for non-contact identification of a signal oscillated on a cable by these oscillators.

According to this configuration, since the first and second oscillators each output a signal of a specific frequency, each oscillator is connected to an end of a cable, and the specific frequency is output from the other end of the cable. Output. Then, when there is no abnormality in the cable, the propagation range of the signal of both frequencies, that is, the range that is more strongly detected, is propagated to a substantially central portion of the cable by, for example, a combination of the signal output level, amplitude, and frequency. Can be enabled. If there is a break in the cable, the signal of each frequency is propagated from both ends of the cable to this break, so that a detector that identifies the specific frequency output to the cable in a non-contact manner is used on the cable. By detecting a change point of the signal in the above, the change point is specified as a damaged portion.

Further, in the present invention, the detector comprises:
It is desirable to have at least one of a light emitting unit and a voice unit as a display unit of the identification result. With this configuration,
When working in a place where detection work by the detector is difficult, for example, in a high place, a narrow place, or a dark place, even if the worker cannot directly see the detector, the detection results can be used by these display means. It is possible to tell the person.

Further, it is desirable that each of the signals has a non-sinusoidal waveform. As a result, the location where the cable is detected for damage is affected by various sources of induction and noise such as inverters, thyristors, high-frequency systems, and communication systems, including the commercial frequency of 50 Hz and 60 Hz. However, by outputting a signal whose signal waveform is different from these noises, the detector can accurately detect the signal.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a cable damage detecting device (hereinafter simply referred to as a detecting device) according to an embodiment of the present invention. This detection device is a transmission / reception type detection device including a first oscillator 1, a second oscillator 2, and a detector 3, and has a handy type configuration. 50 in FIG.
Is a cable. Each of the first oscillator 1 and the second oscillator 2 has a case 4 as shown in FIG. 2 in which a battery as a power supply and an electric circuit described later are incorporated. The case 4 includes a power switch 5,
An output display LED 6 and a connection code 7 are provided. Further, a clip 8 for connecting to the cable 50 is provided at the tip of the connection cord 7. And the first
The oscillator 1, for example 108KH non-sinusoidal waveform _Z (square wave)
The signal X (FIG. 1) of the second oscillator 2 is, for example, 147 KH
It is possible to output a signal Y (FIG. 1) having a non-sinusoidal (rectangular) waveform of _Z. The fact that the first and second oscillators 1 and 2 are operating can be confirmed by turning on the output display LED 6.

As shown in FIG. 3, the detector 3 comprises a main body 9 and a grip 10 to facilitate carrying and detecting work. The main frame portion 9, incorporates an electrical circuitry to be described later, by operating the change-over switch 11, the signal outputted from the first and second oscillators 1 and 2 to the cable 50 X (108KH _Z) or it is possible to receive the signal Y (147KH _Z). In addition, a power switch 12,
It has a battery meter 13, a sensitivity volume 14, and further has detection LEDs 15 and 16 as light emitting means and a detection buzzer 17 as sound means as display means.

When the power switch 12 is turned on and the changeover switch 11 is switched to the X side, the detector 3
It operates to detect the signal X 108KH _Z. When the signal X is detected, 15 of the two detection LEDs 15 and 16 are detected.
Only the light turns on, and the detection buzzer 17 sounds with a certain tone. Further, when switching the changeover switch 11 to the Y side, the detector 3 detects the signal Y 147KH _Z, detect LE
Only D16 lights up and the detection buzzer 17 is a changeover switch
It sounds with a fixed tone different from the one when 11 is switched to the X side. When the signal of the frequency designated by the changeover switch 11 is no longer detected, the detection LE which has been lit up to that time is turned off.
D15 or 16 is turned off, and the detection buzzer 17 does not sound. By providing these detection LEDs 15, 16 and the detection buzzer 17, even when it is difficult to confirm the hand in a dark and narrow place such as a manhole, or when working in a place with a lot of noise, the light emission or sound is used. In addition, the operator can correctly recognize the identification result of the presence / absence of high-voltage cable breakage.

Further, a tip of the main body 9 is a detection unit 18. An output terminal 19 is provided on the main body 9,
By extracting the waveform of the detected signal, it is possible to obtain a more reliable detection result. further,
As shown in FIG. 4, a detachable battery cover 20 is provided on the back surface of the main body 9, so that a battery (not shown) is loaded in a storage box 21 which is closed, and necessary electric power is obtained from the battery. ing.

Next, using the above-mentioned detection device, the cable 50
A procedure for detecting a damaged portion of the device will be described with reference to FIG.

First, the clip 8 of the first oscillator 1 is connected to the shielding layer 52 at the power transmission side end 51 of the cable 50.
Next, the clip 8 of the second oscillator 2 is connected to the shielding layer 52 at the power receiving end 53 of the cable 50. And the first
Power switch 5 of the second oscillator 1 and 2 (see FIG. 2) in the respective ON, the oscillation and the rectangular wave signal X 108KH _Z, a square wave signal Y 147KH _Z relative to the shielding layer 52. Next, the power switch 12 of the detector 3 is turned on, and the sheath of the cable 50 is turned on.
The detection unit 8 is moved closer to 54 and moved from one end of the cable 50 to the other end.

At this time, the power transmission side end 51 to the power reception side end 53
To move the sensor toward
11 is switched to the X direction. Then, by the induction of the signal X oscillated from the first oscillator 1, the detection buzzer
17 sounds and the detection LED 15 lights up. When the detector 3 is moved from the power receiving end 53 to the power transmitting end 51 (when the cable cannot be approached, the detector 3 is moved to the next accessible location).
When 11 is switched to the direction of Y, the detection buzzer 17 sounds and the detection LED 16 is turned on by the induction of the signal Y oscillated from the second oscillator 2.

FIG. 5 shows signals X,
The Y propagation range and the identification pattern of the detector 3 are shown. The uppermost part of FIG. 5 specifically shows a position on the cable 50. First, a case where the cable 50 is normal without any broken portion will be described. Cable 50 at this time
The propagation range of the signals X and Y above extends to substantially the center of the cable as shown in the second row from the top in FIG. Therefore, when the detection work by the detector 3 is started from the power transmission side end 51 of the cable 50, the changeover switch 11 of the detector 3 shown in FIG. Since the signal X is detected, the detection LED 15 is turned on, and the detection buzzer 17 sounds with a constant tone. Then, when the detector 3 approaches the substantially central portion of the cable 50 shown in FIG. 5, the detection LED 15 turns off and the sound of the detection buzzer 17 stops. When the changeover switch 11 is switched in the Y direction immediately after passing through the center of the cable 50, the detector 3 detects the signal Y, so that the detection LED 16 is turned on, and the detection buzzer 17 sets the changeover switch 11 to X Sounds in a different tone than when the direction is switched to.

Further, the detecting operation is performed by using the end of the cable 50 on the power receiving side.
When starting from 53, the changeover switch 11 of the detector 3 shown in FIG. 3 is used by switching in the direction of Y, and the detector 3 detects the signal Y, so that the detection LED 16 is turned on and the detection buzzer 17 is turned on. Sounds with a certain tone. Then, when the detector 3 approaches the center of the cable 50 shown in FIG. 5, the detection LED 16 is turned off and the sound of the detection buzzer 17 is stopped. When the changeover switch 11 is switched in the X direction immediately after passing through the center of the cable 50, the detection L
The ED 15 lights up, and the detection buzzer 17
Sounds in a fixed tone different from that when switching to the X direction. In this way, as shown in the third row from the top in FIG. 5, the changing point of the signals X and Y can be detected as a substantially central portion of the cable 50.

Next, an identification pattern in the case where a damaged portion 55 exists in the cable 50 will be described. If the cable has a damaged portion 55, the signals X and Y propagate from both ends of the cable 50 to the damaged portion 55, as shown in the fourth row from the top in FIG. Therefore, as shown in the fifth row from the top in FIG. 5, the change point of the signals X and Y is detected at the damaged portion 55, so that the damaged portion 55 can be specified.

Next, an identification pattern when two portions 55 and 55 'are damaged will be described. At this time, as shown in the sixth row from the top in FIG. 5, the signal X propagates through the cable 50 from the power transmission side end 51 to the damaged point 55,
The signal Y propagates from the power receiving side end 53 to the damaged portion 55 '. Neither signal propagates between the damaged portions 55 and 55 '. Therefore, when the changeover switch 11 of the detector 3 is switched in the direction of X and the work of detecting the damaged portion is started from the power transmission side end 51 of the cable 50, the detection LED 15 is turned on when the detector 3 approaches the damaged portion 55. The light goes off, and the sounding of the detection buzzer 17 also stops. Immediately after this, even if the changeover switch 11 is switched in the Y direction, the signal Y is not detected, so that the detection LED 16 does not light up and the detection buzzer 17 does not sound.

Further, even when the changeover switch 11 of the detector 3 is switched in the Y direction and the work of detecting the damaged portion is started from the power receiving side end 53, when the detector 3 approaches the damaged portion 55, The detection LED is turned off, and the sound of the detection buzzer 17 also stops. Immediately after this, even if the changeover switch 11 is switched in the X direction, the signal X is not detected, so that the detection LED 15 does not light and the detection buzzer 17 does not sound. This detection pattern is shown at the bottom of FIG. Thus, the cable 50 has (at least) two breaks 55,
55 'is found to exist, and the breaks 55, 55'
Can be specified.

In order to more precisely specify the damaged portion 55 (55 '), it is desirable to make the detector 3 reciprocate several times in the vicinity of the once specified broken portion. According to this method, it is possible to specify a damaged portion within an error of 1%. If the detector 3 cannot be made to approach the sheath 54 of the cable 50 during the detection of the damaged portion (for example, inside the fume tube between adjacent manholes), the detector 3 Of the signals X and Y is specified by bringing the detection unit 18 closer to the cable 50 and increasing the sensitivity of the sensitivity volume 14 of the detector 3.

Now, in the embodiment of the present invention, 108
KH_Z , 147KH_Z Using sinusoidal waveform signals X and Y
The reason was as follows. This is a transmission / reception method
Noise that has an adverse effect on cable damage detection
Sine wave, especially 50H_Z, 60H_ZThe effect of power supply frequency
Focusing on the fact that most of the signals X and Y
Is a commercial frequency that is far away from the effects of these noise systems.
The value and waveform are set in the band. Also, signal X is 1
08KH_Z And signal Y is 147KH_Z And the detector
Due to the characteristics of the circuit used for
When signals X and Y are oscillated from both ends,
A change point of the signal X, Y is detected at the center of the bull.
What we can do has been clarified by our experiments.
In other words, a value that satisfies the above frequency and waveform determination reasons
Then, 108KH_Z And 147KH _Z Limited to the frequency
The waveform is not limited to a square wave,
Not.

The operation and effect obtained from the embodiment of the present invention having the above configuration are as follows. Cable damage detection device according to the embodiment of the present invention includes a first oscillator 1 that oscillates a signal X is a rectangular wave of 108KH _Z, a second oscillator for oscillating a signal Y is a rectangular wave of 147KH _Z 2 And a detector 3 that can identify the signals X and Y from differences in waveform or amplitude, etc.
And the first and second oscillators 1 and 2 are respectively connected to the ends of the cable 50 to output signals X and Y to the cable 50,
The detector 3 identifies the signals X and Y propagated to the cable 50. The detector 3 can identify the signal without contacting the cable 50, and the identification result is detected by the detection L.
An operator can be notified by the EDs 15 and 16 and the detection buzzer 17.

When the cable 50 is normal, the propagation range of the signals X and Y is substantially at the center of the cable 50, and the changing point of the signals X and Y is detected at the substantially center of the cable 50. . However, when the cable 50 has a damaged portion 55, the signals X and Y propagate to the damaged portion 55, respectively. Therefore, the detection pattern becomes different from that in the normal state, and the change point of the signals X and Y at this time can be specified as the damaged portion 55.

Further, since the signals X and Y are rectangular waves, respectively, the location where the cable is detected for damage is in an environment where the noise source such as a commercial frequency of 50 Hz or 60 Hz is affected. Also, since the waveforms are different from these noises, it is possible to accurately detect the signals X and Y. Further, since the detector 3 has the detection LEDs 15 and 16 and the detection buzzer 17 as a display means of the detection result, the light emission and sound of the detector 3 may cause the detector 3 to be used in a place where noise is intense or in an environment where the detector 3 cannot be directly viewed. Even for work, it is possible to notify the worker of the detection result. Further, according to the embodiment of the present invention, it is possible to detect a broken portion of the core wire of the cable 50 by changing the frequency of the signals X and Y. Similarly to the cable identification device disclosed in detail in US Pat. No. 3,323,962, the device can be used as a device for identifying which cable is damaged from a plurality of complicatedly entangled cables.

[0032]

FIG. 6 shows the structure of the electric circuit of the first and second oscillators 1, 2 and the detector 3. FIG. 7 is a detailed diagram of an electric circuit of the oscillators 1 and 2, and FIG.
Of the electric circuit of FIG. First, the oscillators 1 and 2 will be described. As shown in FIGS. 6 and 7, the frequency obtained by the inverter (4069) 22 is adjusted by the capacitor (51PF) 23 and the variable resistor (100 KΩ) 24.
In the frequency of the 108KH _Z, making the frequency of the oscillator 2 147KH _Z, further further calibrated with buffer 25 and the inverter (4069) 26, and an output (27).

Next, referring to FIG. 6 and FIG.
Of the electric circuit will be described. The coil element (L
Detected frequency with 223J) (signal Y signal X or 147KH _Z of 108KH _Z output by the first and second oscillators 1 and 2)
Is amplified by the operational amplifier (TLC277C) 28, the buffer (4069) 29 and the inverter (4069) 30, and the signal input by the changeover switch 11 is distributed. Next, the signal inputted by the Schmitt circuit 31 is shaped into a waveform, and the parallel resonance circuits 32, 3 by LC are formed.
At 2 ', each resonance frequency is extracted. The parallel resonance circuit 32 has L = 0.047 μC and C = 47 μH, and the parallel resonance circuit 32 ′ has L = 0.047 μC and C = 28 μH. And
The voltage level is detected by the diode and the transistor (C-1815) 33 (the transistor is turned on when the voltage is 2 V or more). The buffer (4069) 34, the diode 35, and the RC circuit 36 convert the current to direct current (DC), and the next Schmidt The waveform is formed again by the circuit (4584) 37. Further, the diode (IS1588) 38 prevents reverse current from flowing around, and the transistor (C982) 39 performs polarity inversion and current amplification for lighting the detection LEDs 15 and 16.

The buzzer oscillation circuit 40 includes an analog switch (4
066) To turn on the detection-side transistor 46 via 41, the 680 KΩ resistor 42, 330 KΩ resistor 43 and 0.001
The oscillation frequency is determined by the time constant of the capacitor 44 of F, and an oscillation circuit is formed by using two inverters (4069) 45. The input signal is current-amplified by the transistor 46, and the detection buzzer 17 is turned on. Note that the check button 47 is
Alternatively, the buzzer 17 and the LEDs 15 and 16 are turned on by being turned on when the signal Y is input.

[0035]

According to the present invention, the following effects are obtained. According to the cable damage detection method according to the present invention, a signal having a different frequency is oscillated at each end of the cable, and each signal is propagated to a damaged portion of the cable to detect a change point of the signal. The change point is specified as a broken point. This makes it possible to identify the damaged part of the cable in a non-contact manner and without disassembling the cable. (Because cable repairs are often ordered from outside contractors.) This leads to lower costs.

Further, in the present invention, by performing at least one of the difference in the waveform or the amplitude of both signals, the two signals can be easily and accurately identified, and the damaged portion can be specified more accurately. be able to. Therefore,
It is not necessary to replace the cable over a wide area for repair, but to replace only the bad part. Therefore, it is possible to greatly reduce maintenance costs and material costs.

In addition, by using a non-sinusoidal waveform for the signal, various places such as an inverter, a thyristor, a high-frequency system, and a communication system such as a 50 Hz or 60 Hz system of a commercial frequency can be used to detect a breakage of a cable. Even in an environment affected by induction and noise sources, since the waveform is different from these noises, it is possible to accurately detect the signal and more accurately specify a damaged portion. It becomes possible.

Further, according to the cable breakage detecting device of the present invention, the signals of the specific frequency output to the cable by the first and second oscillators are detected by the detector, so that each signal is detected by the cable. By utilizing the propagation to the broken point, it is possible to identify a change point on the cable of the detected frequency as the broken point. Therefore, it is possible to accurately specify the damaged portion in a non-contact manner, and it is not necessary to replace the cable over a wide area for repair, but to replace only a bad portion, so that a great maintenance is achieved. Costs, material costs and outsourcing costs can be reduced.

Further, in the present invention, at least one of the light emitting means and the sound means is provided as the means for displaying the identification result of the detector, so that the detection operation by the detector is difficult, for example, at a high place or a narrow place. When working in a dark place (manhole, etc.), even if the worker cannot directly see the detector, or even in a place with a lot of noise, the display means can inform the worker of the detection result. Can be. Therefore, it is possible to always accurately specify the damaged portion of the cable without being affected by the working environment.

Further, by using a non-sinusoidal waveform for the signal, a 50 Hz or 60 Hz system of commercial frequency,
It is possible to more accurately identify damaged parts without being affected by various types of induction and noise sources such as inverters, thyristors, high-frequency systems, and communication systems, and to accurately identify damaged parts in various work environments. it can.

As described above, according to the present invention, by providing a highly reliable method for detecting and detecting a cable break in a transmission / reception system, the work of specifying a broken portion of a cable can be performed more accurately and efficiently. It is possible to shorten the operation stop time, and as a result, to reduce the total power supply cost to various facilities.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cable damage detection device according to an embodiment of the present invention and a cable having a damaged portion.

FIG. 2 is a perspective view showing an oscillator of the cable damage detection device shown in FIG.

FIG. 3 is a perspective view showing a detector of the cable damage detecting device shown in FIG. 1;

FIG. 4 is a partial perspective view illustrating a back surface of a main body of the detector illustrated in FIG. 3;

5 is a diagram illustrating a relationship between a propagation range of signals X and Y propagating through a cable and an identification pattern of a detector 3 when the cable damage detection device illustrated in FIG. 1 is used.

FIG. 6 is a block diagram showing an example of a circuit configuration of the cable damage detection device according to the embodiment of the present invention.

FIG. 7 is a circuit diagram showing one embodiment of a circuit constituting the oscillator shown in FIG. 6;

FIG. 8 is a circuit diagram showing one embodiment of a circuit constituting the detector shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st oscillator 2 2nd oscillator 3 Detector 15 Detection LED 16 Detection LED 17 Detection buzzer 18 Detection part X signal Y signal

Claims (6)

[Claims] 1. A signal having a different frequency is oscillated from both ends of a cable having a damaged portion, signals of different frequencies propagating through the cable are identified in a non-contact state, and the damaged portion is identified from the identification result. Cable damage detection method. 2. The cable damage detecting method according to claim 1, wherein the signal having the different frequency is identified by at least one of a difference between waveforms and amplitudes of both signals. 3. The method according to claim 1, wherein the signals have non-sinusoidal waveforms. 4. A first oscillator for outputting a signal of a specific frequency, a second oscillator for outputting a signal of a specific frequency different from the first oscillator, and a signal oscillated on a cable by these oscillators. Cable breakage detection device consisting of a detector that identifies by contact. 5. The cable breakage detecting device according to claim 4, wherein the detector has at least one of a light emitting unit and a sound unit as a display unit of the identification result. 6. The cable damage detecting device according to claim 4, wherein each of the signals has a non-sinusoidal waveform.