JP2008076174A - Method and device for detecting abnormality of shield member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality detecting method of a shield member and a small and inexpensive abnormality detecting device of the shield member capable of inexpensively detecting the abnormality of the shield member using a small device. <P>SOLUTION: A transmitting antenna AT11 and a receiving antenna AT12 are arranged so as to grip a CV cable 10. Thus, the receiving power of the receiving antenna AT12 varies between normal time and abnormal time of copper tape 13 (namely, copper tape 13 is present or absent). The transmitting antenna AT11 is made to transmit electric wave, the receiving antenna AT12 is made to receive electric wave, and abnormality of the copper tape 13 is detected based on the difference between the received power of the received electric wave and the normal receiving power previously measured at the normal time of the copper tape 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shield member abnormality detection method and a shield member abnormality detection device, and more particularly, a conductive core wire, an internal insulator covering the core wire, a shield member wound around an outer periphery of the internal insulator, and The present invention relates to a shield member abnormality detection method and a shield member abnormality detection device for detecting abnormality of the shield member in an electric wire having an external insulator covering the shield member.

  As the electric wire described above, a CV cable for supplying high-voltage power as shown in FIG. 10 is known. FIG. 10 is a cross-sectional view of a CV cable. As shown in the figure, the CV cable 10 includes a core wire 11, an insulator 12 as an internal insulator, a copper tape 13 as a shield member, and a sheath 14 as an external insulator.

  The core wire 11 is made of a conductive conductor. The insulator 12 is made of crosslinked polyethylene or the like and covers the core wire 11. The copper tape 13 is provided to prevent noise from entering from the outside. The copper tape 13 is provided in a tape shape and is wound around the outer periphery of the insulator 12. The sheath 14 is made of polyethylene or the like and covers the copper tape 13.

  In the CV cable 10 described above, the copper tape 13 may be displaced due to laying conditions or secular changes. This misalignment may cause a portion of the core wire 11 that is not covered by the copper tape 13 depending on the location. Thereby, there existed a problem that the performance quality of the CV cable 10 deteriorated.

Conventionally, methods using X-ray imaging have been proposed to detect the displacement of the copper tape 13 (for example, Patent Documents 1 to 4). However, an apparatus capable of X-ray imaging has a problem that the apparatus itself is large and expensive, and qualification is required for imaging, so that versatility is low.
Japanese Patent Publication No. 6-81396 Japanese Examined Patent Publication No. 7-21468 JP-A-6-207826 Japanese Patent Laid-Open No. 5-26647

  Therefore, the present invention pays attention to the above-described problems, and a shield member abnormality detection method capable of detecting an abnormality of the shield member at low cost using a small device and an abnormality of the small and inexpensive shield member. It is an object to provide a detection device.

  In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and the shield member are covered. In an abnormality detection method for a shield member for detecting an abnormality of the shield member in an electric wire having an external insulator, a step of arranging a transmission antenna and a reception antenna so as to sandwich the electric wire, and a step of causing the transmission antenna to transmit radio waves And a step of causing the receiving antenna to receive a radio wave transmitted by the transmission antenna, and the shield based on a difference between a reception power of the radio wave received by the reception antenna and a normal reception power measured in advance when the shield member is normal. And a step of detecting a member abnormality in order.

  The invention according to claim 2 is an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member. In the shield member abnormality detection method for detecting an abnormality of the shield member, the reception antenna receives an interference wave between a direct wave that is a radio wave directly reaching from the transmission antenna and a reflected wave that is a radio wave reaching after being reflected from the transmission antenna by the wire. A step of arranging the transmission antenna and the reception antenna so that reception is possible; a step of transmitting radio waves to the transmission antenna; a step of causing the reception antenna to receive the interference wave; and an interference wave received by the reception antenna. Based on the difference between the received power of the shield member and the normal received power measured in advance when the shield member is normal. It consists in the abnormality detecting method of the shield member, characterized in that performing the step of detecting the atmospheric sequentially.

  The invention according to claim 3 is an electric wire having a conductive core wire, an inner insulator covering the core wire, a shield member wound around the outer periphery of the inner insulator, and an outer insulator covering the shield member. In the abnormality detection apparatus for a shield member that detects an abnormality of a shield member, a transmission antenna that transmits a radio wave and a reception antenna that is disposed so as to sandwich the electric wire between the transmission antenna and transmitting from the transmission antenna And a receiving member for receiving the radio wave. The shield member abnormality detecting device is provided.

  According to the third aspect of the present invention, the transmission antenna transmits radio waves, and the reception antenna disposed so as to sandwich the electric wire between the transmission antennas receives the radio waves transmitted from the transmission antenna. According to the above configuration, a difference occurs in the reception power of the radio wave received by the reception antenna between the normal state and the abnormality time of the shield member, and the abnormality of the shield member can be detected based on the reception power of the reception antenna. Even without X-ray imaging, it is possible to detect an abnormality of the shield member with a simple configuration using a transmission antenna and a reception antenna.

  According to a fourth aspect of the present invention, there is provided the abnormality detecting device for a shield member according to the third aspect, wherein the transmitting antenna transmits a radio wave horizontal to the electric wire.

  According to a fifth aspect of the present invention, there is provided an electric wire having a conductive core wire, an internal insulator that covers the core wire, a shield member that is wound around the outer periphery of the internal insulator, and an external insulator that covers the shield member. In an abnormality detection apparatus for a shield member that detects an abnormality of a shield member, a transmission antenna that transmits radio waves, a direct wave that is a radio wave that directly reaches from the transmission antenna, and a reflection that is a radio wave that arrives after being reflected from the transmission antenna by the wire The present invention relates to an abnormality detecting device for a shield member, comprising a receiving antenna arranged to receive an interference wave with a wave.

  As described above, according to the first to third and fifth aspects of the invention, it is possible to detect an abnormality of the shield member with a simple configuration using the transmission antenna and the reception antenna without performing X-ray imaging. The abnormality of the shield member can be detected at low cost using a small device.

  According to the fourth aspect of the present invention, it is possible to cause a large difference in the received power between when the shield member is normal and when it is abnormal, so that the abnormality of the shield member can be accurately detected.

First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an abnormality detection apparatus for a shield member according to the first embodiment of the present invention. FIG. 2 is an electrical configuration diagram of the abnormality detection device for the shield member shown in FIG. This abnormality detection device detects an abnormality of the copper tape 13 of the CV cable 10, for example. Here, the abnormality of the copper tape 13 means that the copper tape 13 is displaced and a part of the core wire 11 that is not covered with the copper tape 13 is generated.

  As described in the background art, the CV cable 10 includes a core wire 11, an insulator 12 as an internal insulator, a copper tape 13 as a shield member, and a sheath 14 as an external insulator. The core wire 11 is made of a conductive conductor. The insulator 12 is made of crosslinked polyethylene or the like and covers the core wire 11. The copper tape 13 is provided to prevent noise from entering from the outside. The copper tape 13 is provided in a tape shape and is wound around the outer periphery of the insulator 12. The sheath 14 is made of polyethylene or the like and covers the copper tape 13.

  The abnormality detection device 20 includes a transmission unit 21, a reception unit 22, and an attachment unit 23. Further, as shown in FIG. 2, the abnormality detection device 20 includes a display control unit 24 as display control means and a display 25 as display means. As shown in FIG. 2, the transmitter 21 transmits an oscillation circuit 26 that outputs an oscillation signal having a predetermined frequency, an amplifier 27 that amplifies the oscillation signal, and a radio wave having a predetermined frequency that is supplied with the amplified oscillation signal. Transmitting antenna AT11.

  The receiving unit 22 receives a radio wave of a predetermined frequency, a receiving circuit 28 that demodulates the radio wave received by the receiving antenna AT12 and outputs a received power signal corresponding to the received power to the display control unit 24. It has. The display control unit 24 reads the received power from the received power signal and causes the display 25 to display the received power.

  The attachment portion 23 includes a pair of flat plate-like holding portions 231 and a flat plate-like support portion 232 that connects one side of the holding portion 231. The attachment portion 23 is supported by the CV cable 10 by the support portion 232. The CV cable 10 is sandwiched between a pair of holding portions 231. The pair of holding parts 231 are provided with a transmission part 21 and a reception part 22, respectively.

  With the mounting portion 23, the transmission antenna AT11 and the reception antenna AT12 are arranged so that the CV cable 10 is sandwiched between the transmission antenna AT11 and the reception antenna AT12. The mounting portion 23 may be provided with a pulley, for example, to facilitate movement on the CV cable 10. Moreover, the pulley provided in the attachment part 23 may be driven by a motor so that the abnormality detection device 20 can automatically move on the CV cable 10.

  The transmission antenna AT11 transmits a horizontal radio wave to the CV cable 10. Specifically, as shown in FIG. 3, the transmission antenna AT11 is provided so as to generate a radio wave so that the direction in which the electric field component of the radio wave is generated and the CV cable 10 are horizontal. On the contrary, the generation direction of the magnetic field component of the radio wave is perpendicular to the CV cable 10.

  In the abnormality detection device 20 configured as described above, a difference occurs in the reception power of the reception antenna AT12 when the copper tape 13 is present (when normal) and when the copper tape 13 is absent (when abnormal). What is considered as one of the principles will be described below with reference to FIG. FIG. 4A is an image diagram showing radio waves that directly reach the receiving antenna AT12 from the transmitting antenna AT11 when the copper tape 13 is present. FIG. 4B is an image diagram showing radio waves that directly reach the receiving antenna AT12 from the transmitting antenna AT11 when the copper tape 13 is not present. In FIG. 4, arrows indicate the progress of radio waves.

  As shown in FIG. 4A, when the CV cable 10 has the copper tape 13, most of the radio waves from the transmission antenna AT11 are blocked by the copper tape 13 having a large diameter. On the other hand, as shown in FIG. 4B, when there is no copper tape 13 in the CV cable 10, only the core wire 11 blocks the radio wave from the transmission antenna AT11, and the radio wave from the transmission antenna AT11 is hardly blocked. To the receiving antenna AT12.

  Since the insulator 12 between the copper tape 13 and the core wire 11 is about 4 to 5 mm regardless of the thickness of the CV cable 10, the shielding effect when the copper tape 13 is present is enhanced. Therefore, when there is no copper tape 13, higher reception power can be obtained at the receiving antenna AT12 than when the copper tape 13 is present.

  Next, an abnormality detection method using the above-described abnormality detection device 20 will be described. First, the worker attaches the attachment portion 23 of the abnormality detection device 20 to the CV cable 10. Thus, as shown in FIG. 1, the transmission antenna AT11 and the reception antenna AT12 are arranged so that the CV cable 10 is sandwiched between the transmission antenna AT11 and the reception antenna AT12.

  Next, the operator operates the abnormality detection device 20 to oscillate the oscillation circuit 26 of the transmission unit 21. As a result, a radio wave is transmitted from the transmission antenna AT11 toward the reception antenna AT12. When a radio wave is transmitted from the transmission antenna AT11, the reception antenna AT12 receives the radio wave. The receiving circuit 28 demodulates the radio wave received by the receiving antenna AT12 and outputs a received power signal corresponding to the received power to the display control unit 24. The display control unit 24 reads the received power from the received power signal and causes the display 25 to display the received power.

  Next, the operator reads the received power displayed on the display unit 25, and transmits if the difference between the read received power and the normal received power measured in advance when the copper tape 13 is present (normal) is small. It is determined that there is a copper tape 13 between the antenna AT11 and the receiving antenna AT12, and that there is no abnormality in the copper tape 13. On the other hand, if the difference between the read reception power and the normal reception power is large, it is determined that there is no copper tape 13 between the transmission antenna AT11 and the reception antenna AT12, and the copper tape 13 is displaced and an abnormality has occurred.

  Next, the operator moves the attachment portion 23 of the abnormality detection device 20 along the CV cable 10. Then, the received power displayed on the display unit 25 is read to check whether there is an abnormality in the CV cable 10. The operator moves the mounting portion 23 of the abnormality detection device 20 over the entire length of the inspected portion of the CV cable 10 and reads the received power displayed on the display unit 25 each time it is moved. Inspect for any occurrence.

  In the abnormality detection method and abnormality detection apparatus 20 described above, the transmission antenna AT11 and the reception antenna AT12 are arranged so as to sandwich the CV cable 10. As a result, a difference occurs in the reception power of the reception antenna AT12 with and without the copper tape 13. Then, the radio wave transmitted by the transmission antenna AT11 is received by the reception antenna AT12, and the abnormality of the copper tape 13 is detected based on the difference between the reception power and the normal reception power measured in advance. Therefore, the abnormality of the copper tape 13 can be detected with a simple configuration using the transmission antenna AT11 and the reception antenna AT12 without performing X-ray imaging, and the abnormality of the copper tape 13 can be detected inexpensively with a small apparatus. be able to.

  Further, according to the abnormality detection device 20 described above, since the transmission antenna AT11 transmits a horizontal radio wave to the CV cable 10, there is a large difference in reception power between when the copper tape 13 is present and when it is absent. And the abnormality of the copper tape 13 can be accurately detected.

  Next, the present inventor manufactures a plurality of abnormality detection devices 20 having different arrangement positions of the transmission antenna AT11 and the reception antenna AT12, and there is no reception power of the reception antenna AT12 and the copper tape 13 when these copper tapes 13 are present. In this case, the effect of the present invention was confirmed by measuring the reception power of the reception antenna AT12. The results are shown in FIG.

The CV cable 10 used in the measurement of FIG. 5 has a cable outer diameter of 38 mm and a core wire size of 325 mm ² . In FIG. 5, the square indicates the received power when the copper tape 13 is present, and the circle indicates the received power when the copper tape 13 is not present.

FIG. 5 will be described. The transmission antenna AT11 and the reception antenna AT12 used in the measurement of FIG. 5 are 2.45 GHz patch antennas, and the size thereof is a square of 60 mm ² . Further, regarding the arrangement positions of the transmission antenna AT11 and the reception antenna AT12 used in the measurement of FIG. 5A, the antenna angle θ1 (see FIG. 6) is 0 ° and 20 °, and the antenna position L1 (see FIG. 6). It was varied between 3 cm and 15 cm. It was found that substantially the same received power can be obtained when the antenna angle θ1 is 0 ° and 20 °.

  In addition, the arrangement positions of the transmission antenna AT11 and the reception antenna AT12 used in the measurement of FIG. 5B are 30 ° in the antenna angle θ1 shown in FIG. 6, and the antenna position L1 is changed between 3 cm and 15 cm. . Further, the arrangement positions of the transmission antenna AT11 and the reception antenna AT12 used in the measurement of FIG. 5C are such that the antenna angle θ1 shown in FIG. 6 is 45 ° and the antenna position L1 is changed between 1 cm and 15 cm. . Further, the arrangement positions of the transmission antenna AT11 and the reception antenna AT12 used in the measurement of FIG. 5D are such that the antenna angle θ1 shown in FIG. 6 is 60 °, and the antenna position L1 is changed between 3 cm and 15 cm. .

  From FIG. 5, it was found that the smaller the antenna angle θ1, the greater the difference in received power with and without the copper tape 13. It was also found that the closer the antenna position L1, the greater the difference in received power with and without the copper tape 13. This is considered to be the phenomenon described in FIG.

  On the other hand, as shown in FIG. 5 (d), it was found that when the antenna angle θ1 is 60 °, there is almost no difference in received power between when the copper tape 13 is present and when it is absent. It was also found that when the antenna position L1 is far, there is almost no difference in received power between when the copper tape 13 is present and when it is absent. This is because the CV cable 10 cannot be sandwiched between the transmitting antenna AT11 and the receiving antenna AT12 if the antenna angle θ1 is large and the antenna position L1 is far.

  From FIG. 5, if the transmitting antenna AT11 and the receiving antenna AT12 are arranged so that the CV cable 10 is sandwiched between the transmitting antenna AT11 and the receiving antenna AT12, the receiving antenna AT12 can be used with or without the copper tape 13. It was found that there was a difference in the received power of the received radio waves. It is desirable to arrange the transmission antenna AT11 and the reception antenna AT12 described above so that the difference between the reception powers of the radio waves received by the reception antenna AT12 increases with and without the copper tape 13.

  In addition, the inventor has an abnormality detection device 20 having a transmission antenna AT11 that transmits a horizontal radio wave to the CV cable 10 and an abnormality detection device 20 having a transmission antenna AT11 that transmits a vertical radio wave to the CV cable 10. And the reception power of the reception antenna AT12 when the copper tape 13 is present and the reception power when the copper tape 13 is not present are measured to confirm the effect of the present invention. As a result of the measurement, the receiving antenna AT12 is transmitted when the horizontal radio wave is transmitted to the CV cable 10 with and without the copper tape 13 as compared with the case where the vertical radio wave is transmitted with respect to the cable 10. It was found that the difference in received power of received radio waves increased.

  In the first embodiment described above, patch antennas are used as the transmission antenna AT11 and the reception antenna AT12. However, the present invention is not limited to this. The transmitting antenna AT11 and the receiving antenna AT12 may be anything.

  In the first embodiment described above, the transmission antenna AT11 transmits a horizontal radio wave to the CV cable 10, but the present invention is not limited to this. For example, if there is a difference in the reception power of the reception antenna AT12 with and without the copper tape 13, it may not be horizontal with respect to the CV cable 10.

Second Embodiment Next, a second embodiment will be described. FIG. 7 is a configuration diagram of the abnormality detection device for a shield member according to the present invention in the second embodiment. Since the CV cable 10 is the same as that described in the first embodiment, a detailed description thereof is omitted here.

  The abnormality detection device 30 includes a transmission unit 31, a reception unit 32, and an attachment unit (not shown). The abnormality detection device 30 includes a discriminator 33 as a discriminating unit and an alarm unit 34 as an alarm unit. The transmission unit 31 includes an oscillation circuit 35 that outputs a transmission signal with a predetermined frequency, an amplifier 36 that amplifies the oscillation signal, and a transmission antenna AT21 that receives the amplified oscillation signal and transmits a radio wave with a predetermined frequency. ing.

  The receiving unit 32 includes a receiving antenna AT22 that receives radio waves of a predetermined frequency, and a receiving circuit 37 that demodulates the radio waves received by the receiving antenna AT22 and outputs a received power signal corresponding to the received power to the discriminator 33. I have. The discriminator 33 reads the received power from the received power signal and determines whether there is an abnormality in the copper tape 13 based on the received power. When the discriminator 33 determines that there is an abnormality, the alarm device 34 generates an alarm to notify that.

  Moreover, it is possible to use the attachment part 23 similar to 1st Embodiment, for example as an attachment part. Due to the mounting portion, the transmission antenna AT21 and the reception antenna AT22 have a direct wave W1 that is a radio wave that reaches directly from the transmission antenna AT21 and a reflected wave W2 that arrives after being reflected by the copper tape 13 or the core wire 11 of the CV cable 10 from the transmission antenna AT21. The interference wave is arranged so that it can be received by the receiving antenna AT22.

  In the abnormality detection device 30 configured as described above, there is a difference in the reception power of the reception antenna AT22 when the copper tape 13 is present and when it is not present. What is considered as one of the principles will be described below. As shown in FIG. 7A, when the copper tape 13 is present, the receiving antenna AT22 has a direct wave W1 that directly reaches from the transmitting antenna AT21 and a reflected wave W2 that is reflected from the transmitting antenna AT21 by the copper tape 13 and reaches. Receive interference waves.

  On the other hand, as shown in FIG. 7 (b), when there is no copper tape 13, the receiving antenna AT22 has a direct wave W1 directly reaching from the transmitting antenna AT21 and a reflected wave W1 reflected by the core wire 11 from the transmitting antenna AT21. The interference wave is received. Since the thickness of the insulator 12 is about 4 to 5 mm, the path length of the reflected wave W2 with and without the copper tape 13 is different, and as a result, the intensity of the interference wave is different.

  Next, an abnormality detection method using the above-described abnormality detection device 30 will be described. First, the worker attaches an attachment portion (not shown) of the abnormality detection device 30 to the CV cable 10. Accordingly, as shown in FIG. 7, the transmission antenna AT21 and the reception antenna AT22 are arranged so that the reception antenna AT22 can receive the interference wave between the direct wave W1 and the reflected wave W2.

  Next, the operator operates the abnormality detection device 30 to oscillate the oscillation circuit 35 of the transmission unit 31. Thereby, a radio wave is transmitted from the transmission antenna AT21. When a radio wave is transmitted from the transmission antenna AT21, the reception antenna AT22 receives the interference wave. The receiving circuit 37 modulates the interference wave received by the receiving antenna AT22 and outputs a received power signal corresponding to the received power to the discriminator 33. The discriminator 33 reads the received power from the received power signal and determines whether or not the copper tape 13 is present based on the received power.

  The abnormality detection device 30 has a setting mode. When the abnormality detection device 30 is securely attached to the CV cable 10 with the copper tape 13 in the setting mode, the abnormality detection device 30 converts the reception power of the interference wave received by the reception antenna AT22 at this time to the copper tape. 13 is stored as the received power.

  The discriminator 33 reads the received power from the received power signal, and determines that there is no copper tape 13 when the difference between the received power and the received power with the copper tape 13 stored in advance in the setting mode is greater than or equal to the threshold value. To do. Then, when the discriminator 33 determines that the copper tape 13 is not present, the alarm device 34 generates an alarm that notifies that fact.

  Next, the worker moves an attachment portion (not shown) of the abnormality detection device 20 along the CV cable 10. The operator moves the mounting portion of the abnormality detection device 20 over the entire length of the portion to be inspected of the CV cable 10 and inspects whether there is an abnormality in the CV cable 10.

  According to the abnormality detection method and the abnormality detection apparatus 30 described above, an interference wave between a direct wave W1 that is a radio wave that reaches directly from the transmission antenna AT21 and a reflected wave W2 that is a radio wave that arrives after being reflected by the CV cable 10 from the transmission antenna AT21. The transmission antenna AT21 and the reception antenna AT22 are arranged so that the reception antenna AT22 can receive. As a result, there is a difference in the reception power of the interference wave by the reception antenna AT22 with and without the copper tape 13. Then, radio waves are transmitted to the transmission antenna AT21, interference waves are received by the reception antenna AT22, and an abnormality of the copper tape 13 is detected based on the reception power of the interference waves received by the reception antenna AT22. Therefore, the abnormality of the copper tape 13 can be detected with a simple configuration using the transmission antenna AT21 and the reception antenna AT22 without performing X-ray imaging, and the abnormality of the copper tape 13 can be detected at low cost using a small apparatus. Can be detected.

  Next, the present inventor manufactures an abnormality detection device 30 that can change the antenna-cable distance L2 between the transmission antenna AT21 and the reception antenna AT22 and the CV cable 10, and the case where these copper tapes 13 exist and the copper tape 13 The effect of the present invention was confirmed by measuring the reception power of the reception antenna AT22 with and without the case. The results are shown in FIG. The horizontal axis of FIG. 8A is the antenna-cable distance L2, and the vertical axis is the reception power of the reception antenna AT22. 8B, the horizontal axis represents the antenna-cable distance L2, and the vertical axis represents the reception power difference between the reception power when the copper tape 13 is present and the reception power when the copper tape 13 is not present.

The CV cable 10 used in the measurement of FIG. 8 has a cable outer diameter of 38 mm and a core wire size of 325 mm ² . Further, in FIG. 8A, black circles indicate received power when the copper tape 13 is present, and white circles indicate received power when the copper tape 13 is not present.

  First, FIG. 8 will be described. The transmission antenna AT21 and the reception antenna AT22 used in the measurement of FIG. 8 are 2.8 GHz band antennas. The antenna angle θ2 (see FIG. 7) is 45 °, and the displacement width of the copper tape 13 is 5 cm. In the measurement of FIG. 8, the antenna-cable distance L2 was changed between 2 and 24 cm.

  As shown in FIG. 8A, when the antenna-cable distance L2 is a short distance, the position of the minimum received power differs depending on whether the copper tape 13 is present or not. This is because the phase difference of the reflected wave W2 shown above is different. As a result, as shown in FIG. 8B, the maximum received power difference was 12 dB when the antenna-cable distance L2 was 3.5 cm.

  In this experiment, since antennas with wide directivity are used as the transmission antenna AT21 and the reception antenna AT22, when the antenna-cable distance L2 becomes a long distance, the influence of the copper tape 13 is affected even when the copper tape 13 is not present. It became clear that the reception level difference could not be obtained.

  In addition, the inventor has received the reception antenna AT22 when there is the copper tape 13 of the abnormality detection device 30 and when there is no copper tape 13 in which the antenna-cable distance L2 between the transmission antenna AT21 and the reception antenna AT22 and the CV cable 10 is different. The received power was simulated. The results are shown in FIG. The horizontal axis of FIG. 9A is the antenna-cable distance L2, and the vertical axis is the reception power of the reception antenna AT22. 9B, the horizontal axis represents the antenna-cable distance L2, and the vertical axis represents the reception power difference between the reception power when the copper tape 13 is present and the reception power when the copper tape 13 is not present.

  Characteristics close to the measurement result shown in FIG. 8 and the simulation result shown in FIG. 9 are obtained. Since this anomaly detection method uses radio wave interference, if the level of the direct wave W1 and that of the reflected wave W2 are theoretically the same and the phase difference is 180 °, the reception level is 0 (mW). Become.

  In addition, it is desirable to arrange the transmission antenna AT21 and the reception antenna AT22 described above so that the difference in the reception power of the radio wave received by the reception antenna AT22 increases with and without the copper tape 13. For example, in the example shown in FIG. 8, it is desirable to arrange the transmission antenna AT21 and the reception antenna AT22 so that the antenna-cable distance L2 is 3 cm or 5 cm.

  In the first embodiment described above, the presence or absence of the copper tape 13 is determined by looking at the received power displayed on the display 25 by the operator. However, the present invention is not limited to this. For example, as in the second embodiment, the abnormality detection device 20 may determine the presence or absence of the copper tape 13 based on the received power using a discriminator.

  In the second embodiment described above, the discriminator 33 determines the presence or absence of the copper tape 13 based on the received power, but the present invention is not limited to this. For example, as in the first embodiment, the operator may determine the presence or absence of the copper tape 13 by looking at the received power displayed on the display.

  In the first and second embodiments described above, the abnormality of the copper tape 13 of the CV cable 10 in which one copper tape 13 is wound around the core wire 11 with the insulator 12 interposed therebetween is detected. The present invention is not limited to this. As the CV cable 10, there is also a cable in which the copper tape 13 is wound in a double or triple manner with an insulator 12 sandwiched around the core wire 11. Such an abnormality of the copper tape 13 of the CV cable 10 can also be detected.

  In the first and second embodiments described above, the transmitting antennas AT11 and A21 and the receiving antennas AT12 and AT22 are attached using the U-shaped attachment portion 23 as shown in FIG. It is not limited to this. In the case of the first embodiment, the attachment portion may be any one that arranges the transmission antenna AT11 and the reception antenna AT12 so as to sandwich the CV cable 10. Further, in the case of the second embodiment, the mounting portion is such that the transmission antenna AT21 and the reception antenna AT22 are arranged so that the reception antenna AT22 can receive the interference wave between the direct wave W1 and the reflected wave W2. That's fine.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram of the abnormality detection apparatus of the shield member of this invention in 1st Embodiment. It is an electrical block diagram of the abnormality detection apparatus of the shield member shown in FIG. It is a figure which shows the relationship between an electromagnetic wave and a CV cable. (A) is an image figure which shows the electromagnetic wave which reaches | attains a receiving antenna directly from a transmission antenna with a copper tape, (b) is an image figure which shows the electromagnetic wave which reaches a receiving antenna directly from a transmission antenna when there is no copper tape. is there. (A)-(d) is a graph which shows the relationship between an antenna angle, an antenna position, and reception power when a 2.45-GHz patch antenna is used as a transmission antenna and a receiving antenna. It is a figure which shows the arrangement | positioning relationship of a transmission antenna and a receiving antenna. It is a block diagram of the abnormality detection apparatus of the shield member of this invention in 2nd Embodiment. (A) is a graph which shows the relationship between receiving power and antenna-cable distance, (b) is a graph which shows the relationship between receiving power difference with and without a copper tape, and antenna-cable distance. is there. (A) is a graph which shows the relationship between receiving power and antenna-cable distance, (b) is a graph which shows the relationship between receiving power difference with and without a copper tape, and antenna-cable distance. is there. It is sectional drawing of a CV cable.

Explanation of symbols

10 CV cable (electric wire)
11 Core wire 12 Insulator (Internal insulator)
13 Copper tape (shield member)
14 Sheath (external insulator)
AT11 transmitting antenna AT12 receiving antenna AT21 transmitting antenna AT22 receiving antenna W1 direct wave W2 reflected wave

Claims (5)

A shield for detecting abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member In the member abnormality detection method,
Arranging a transmitting antenna and a receiving antenna so as to sandwich the electric wire;
Transmitting radio waves to the transmitting antenna;
Receiving the radio wave transmitted by the transmitting antenna at the receiving antenna;
A step of detecting an abnormality of the shield member based on a difference between a reception power of a radio wave received by the reception antenna and a normal reception power measured in advance when the shield member is normal. Anomaly detection method. A shield for detecting abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member In the member abnormality detection method,
The transmission antenna and the reception antenna are arranged so that the reception antenna can receive an interference wave between a direct wave that is a radio wave that reaches directly from the transmission antenna and a reflected wave that is a radio wave that arrives after being reflected by the electric wire from the transmission antenna. Process,
Transmitting radio waves to the transmitting antenna;
Receiving the interference wave at the receiving antenna;
A step of detecting an abnormality of the shield member in order based on a difference between a reception power of an interference wave received by the reception antenna and a normal reception power measured in advance when the shield member is normal. Anomaly detection method. A shield for detecting abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member In the member abnormality detection device,
A transmitting antenna that transmits radio waves,
An abnormality detection of a shield member, comprising: a reception antenna disposed so as to sandwich the electric wire between the transmission antenna and a reception antenna that receives the radio wave transmitted from the transmission antenna apparatus.   4. The shield member abnormality detection device according to claim 3, wherein the transmission antenna transmits a horizontal radio wave with respect to the electric wire. A shield for detecting abnormality of the shield member in an electric wire having a conductive core wire, an internal insulator covering the core wire, a shield member wound around the outer periphery of the internal insulator, and an external insulator covering the shield member In the member abnormality detection device,
A transmitting antenna that transmits radio waves,
A receiving antenna arranged to receive an interference wave between a direct wave that is a radio wave that reaches directly from the transmitting antenna and a reflected wave that is a radio wave that arrives after being reflected from the transmitting antenna by the wire. An apparatus for detecting an abnormality of a shield member.

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