JP2015072217A - Position locating method of distortion amount change place of insulated wire or cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position locating method of a distortion amount change place of an insulated wire or cable capable of locating a position of the distortion amount change place of the insulated wire or cable in a predetermined portion of the insulated wire or cable.SOLUTION: A position locating method of a distortion amount change place of an insulated wire or cable having a conductor and insulator in an aspect of the present invention, includes the steps of: measuring a magnitude or phase angle of characteristic impedance of the insulated wire or cable, or a frequency spectrum of a signal changed due to characteristic impedance change; converting the frequency spectrum to a position spectrum that is a function of a position on the insulated wire or cable; and locating the position of the distortion amount change place on the insulated wire or cable from the waveform of the position spectrum.

Description

  The present invention relates to a position locating method for a strain amount change portion of an insulated wire or cable.

  Conventionally, by embedding two conductor wires inside a structure and capturing changes in the characteristic impedance of the parallel two lines composed of these conductor wires, the amount of moisture in the area around the conductor wires in the structure is reduced. A technique for detecting an increase or the like is known (for example, see Patent Document 1).

  According to Patent Document 1, the change in the moisture content is detected from the change in the characteristic impedance depending on the dielectric constant by utilizing the change in the dielectric constant of the structure due to the change in the moisture content.

Japanese Patent Laid-Open No. 11-173998

  One of the objects of the present invention is to determine the position of a strain amount change point of an insulated wire or cable, which can determine the position of the strain amount change point of the insulated wire or cable in a predetermined part of the insulated wire or cable. It is to provide a method.

  (1) According to one aspect of the present invention, in order to achieve the above object, there is provided a method for locating a strain amount change portion of an insulated wire or cable having a conductor and an insulator, wherein the characteristic impedance of the insulated wire or cable is as follows. Measuring a frequency spectrum of a signal that changes due to a magnitude or phase angle or characteristic impedance change thereof, and converting the frequency spectrum into a position spectrum that is a function of the position on the insulated wire or cable; And a step of locating the position of the strain amount change portion on the insulated wire or cable from the waveform of the position spectrum, and a method for locating the strain amount change portion of the insulated wire or cable.

  (2) In the position determining method of the strain amount change portion of the insulated wire or cable, the conductor includes a first conductor and a second conductor, and at least a part of the insulator includes the first conductor and the first conductor. It is preferable that it is located between two conductors.

  (3) In the position determining method of the distortion amount changing portion of the insulated wire or cable, the frequency spectrum is converted into a time spectrum which is a spectrum of a function of time by inverse Fourier transform, and the speed of the electric signal in the insulator You may convert into the said position spectrum by multiplying.

  (4) In the position locating method of the strain amount change portion of the insulated wire or cable, the waveform of the position spectrum is compared with the waveform of the position spectrum in a state before the change of the strain amount of the insulated wire or cable occurs. Thus, the position of the distortion amount changing portion may be determined.

  (5) In the position determination method of the strain amount change portion of the insulated wire or cable, the position of the strain amount change portion of the coaxial cable as the cable may be determined.

  (6) In the above-described method for locating the strain amount change portion of the insulated wire or cable, the position of the strain amount change portion of the insulated flat cord as the insulated wire may be located.

  (7) In the position determination method of the strain amount change portion of the insulated wire or cable, the position of the strain amount change portion of the multicore cable as the cable may be determined.

  (8) In the position locating method of the distortion amount changing portion of the insulated wire or cable, the number of measurement points of the frequency spectrum may be increased by interpolation and then converted to the position spectrum.

  According to the present invention, there is provided a position locating method for a strain amount change portion of an insulated wire or cable, which can determine the position of the strain amount change portion of the insulated wire or cable in a predetermined portion of the insulated wire or cable. can do.

Fig.1 (a) is sectional drawing of the insulated flat cord as an example of the insulated wire which concerns on embodiment. FIG. 1B is a cross-sectional view of a three-core cable as an example of the cable according to the embodiment. FIG. 2 is a cross-sectional view of a coaxial cable as an example of the cable according to the embodiment. FIG. 3 is a flowchart showing the flow of the position locating method of the distortion amount changing portion of the insulated wire and cable according to the present embodiment. FIG. 4 is a side view schematically illustrating a state in which the coaxial cable is clamped according to the first embodiment. FIG. 5A shows the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave, which changes due to the characteristic impedance change of the coaxial cable in the frequency band of 1 to 100 MHz, according to the first embodiment, and the dotted line is The reference spectrum is a spectrum when the coaxial cable is not clamped, and the solid line is the spectrum when the coaxial cable is clamped. FIG. 5B shows a difference spectrum between a spectrum in a state where the coaxial cable shown in FIG. 5A is sandwiched between clamps and a reference spectrum. FIG. 6A shows the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz according to the first embodiment, and the dotted line is the dotted line. The reference spectrum is a spectrum when the coaxial cable is not clamped, and the solid line is the spectrum when the coaxial cable is clamped. FIG. 6B shows a difference spectrum between a spectrum in a state where the coaxial cable shown in FIG. 6A is clamped and a reference spectrum. FIG. 7A shows the position spectrum of the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 1500 MHz according to the first embodiment. The reference spectrum is a spectrum when the coaxial cable is not clamped, and the solid line is the spectrum when the coaxial cable is clamped. FIG. 7B shows a difference spectrum between a spectrum in a state where the coaxial cable shown in FIG. 7A is sandwiched between clamps and a reference spectrum. FIG. 8A shows the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz according to the first embodiment, and the dotted line is the dotted line. The reference spectrum is a spectrum when the coaxial cable is not clamped, and the solid line is the spectrum when the clamp is removed from the coaxial cable. FIG. 8B shows a difference spectrum between the spectrum in a state where the clamp is removed from the coaxial cable shown in FIG. 8A and the reference spectrum. FIGS. 9A and 9B are side views schematically showing a state in which the coaxial cable is mounted on an L-shaped angle and a state sandwiched between two L-shaped angles, respectively, according to the second embodiment. FIG. 10A shows the position spectrum of the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz according to the second embodiment, and the dotted line is the dotted line. The reference spectrum is a spectrum when the coaxial cable is not placed on the L-shaped angle, and the solid line is the spectrum when the coaxial cable is placed on the L-shaped angle. FIG.10 (b) shows the difference spectrum of the spectrum of the state which mounted the coaxial cable shown by Fig.10 (a) on the L-shaped angle, and a reference spectrum. FIG. 11A shows the position spectrum of the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz according to Example 2, and the dotted line is the dotted line. The reference spectrum is a spectrum when the coaxial cable is not sandwiched between L-shaped angles, and the solid line is the spectrum when the coaxial cable is sandwiched between two L-shaped angles. FIG. 11B shows a difference spectrum between a spectrum in a state where the coaxial cable shown in FIG. 11A is sandwiched between two L-shaped angles and a reference spectrum. FIG. 12A shows the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz according to the second embodiment, and the dotted line is the dotted line. A reference spectrum that is a spectrum in a state where the coaxial cable is not sandwiched between L-shaped angles, and a solid line is a spectrum in which only the upper L-shaped angle is removed after the coaxial cable is sandwiched between two L-shaped angles. . FIG. 12B shows a difference spectrum between a spectrum in which the upper L-shaped angle is removed after the coaxial cable shown in FIG. 12A is sandwiched between two L-shaped angles and a reference spectrum. FIG. 13 is a side view schematically illustrating a state in which an insulating flat cord is sandwiched between two L-shaped angles according to the third embodiment. FIG. 14A shows a position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the characteristic impedance change of the insulated flat cord in the frequency band of 1 to 100 MHz according to the third embodiment, and is a dotted line. Is a reference spectrum which is a spectrum in a state where an insulated flat cord is not sandwiched between L-shaped angles, and a solid line is a spectrum in a state where an insulated flat cord is sandwiched between two L-shaped angles. FIG. 14B shows a difference spectrum between a spectrum in a state where the insulating flat cord shown in FIG. 14A is sandwiched between two L-shaped angles and a reference spectrum. FIG. 15A shows a frequency band of 1 to 800 MHz obtained by performing measurement by connecting a network analyzer to the first conductor and the second conductor of the three-core cable according to Example 4. The position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the three-core cable is shown. The dotted line is a reference spectrum that is a spectrum when the three-core cable is not sandwiched between clamps. Is a spectrum with a three-core cable sandwiched between clamps. FIG. 15B shows a difference spectrum between a spectrum in a state where the three-core cable shown in FIG. 15A is clamped and a reference spectrum. FIG. 16A shows a frequency band of 1 to 800 MHz obtained by performing measurement by connecting a network analyzer to the second conductor and the third conductor of the three-core cable according to Example 4. The position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the three-core cable is shown. The dotted line is a reference spectrum that is a spectrum when the three-core cable is not sandwiched between clamps. Is a spectrum with a three-core cable sandwiched between clamps. FIG. 16B shows a difference spectrum between a spectrum in a state where the three-core cable shown in FIG. FIG. 17A shows a frequency band of 1 to 800 MHz obtained by performing measurement by connecting a network analyzer to the third conductor and the first conductor of the three-core cable according to Example 4. The position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the three-core cable is shown. The dotted line is a reference spectrum that is a spectrum when the three-core cable is not sandwiched between clamps. Is a spectrum with a three-core cable sandwiched between clamps. FIG. 17B shows a difference spectrum between a spectrum in a state where the three-core cable shown in FIG.

[Embodiment]
The inventors of the present invention have found that the magnitude of the characteristic impedance of the insulated wire or cable in the high frequency band, the phase angle thereof, and the spectrum of the signal such as voltage and power that change due to the characteristic impedance change are distorted by the insulated wire or cable. It has been found that changes.

  Specifically, for example, a single-core insulated wire composed of a conductor and an insulator provided on the outer periphery of the conductor, or a coaxial cable formed by using one or more insulated wires composed of the single core, Insulation of signals such as voltage and power that change due to the magnitude and phase angle of the characteristic impedance and changes in the characteristic impedance when the amount of distortion at a specific point of the cable made of multi-core cable or insulated flat cord changes. The height of the peak of the position corresponding to the distortion amount changing portion of the spectrum (position spectrum) expressed as a function of the position on the electric wire or cable changes.

  As a cause of the amount of distortion change, for example, bending of an insulated wire or cable, pressurization from a contacting member, and the like can be cited. Specifically, for example, when the cables overlap in the switchboard, the overlapping portions are pressed and distortion occurs. Further, the position of a part of the cable is shifted from the original laying position, the bent state of the shifted part is changed, and the amount of distortion is changed. The cable will be described below, but the same applies to the insulated wire.

  According to the present embodiment, the position spectrum of a signal such as a voltage or power that changes due to the magnitude or phase angle of the characteristic impedance or a change in the characteristic impedance is measured using a network analyzer, an impedance analyzer, or the like. It is obtained by converting a spectrum (frequency spectrum) expressed as a function of the frequency of a signal such as voltage or power that changes due to the magnitude of the characteristic impedance or its phase angle or a change in characteristic impedance. For example, the position spectrum is obtained by converting the frequency spectrum into a time spectrum which is a spectrum expressed as a function of time by inverse Fourier transform, and further multiplying by the speed of the electrical signal in the insulator between the conductors of the cable.

  Note that the frequency band of the network analyzer (for example, 1 to 1500 MHz) is wider than the frequency band of the impedance analyzer (for example, 1 to 110 MHz) and has high position resolution. Therefore, in this embodiment, the network analyzer is used. It is preferable to measure the frequency spectrum of signals such as voltage and power that change due to characteristic impedance changes.

  The frequency spectrum of a signal such as voltage and power that changes due to the magnitude and phase angle of the characteristic impedance and the change in the characteristic impedance is measured by connecting a measuring device such as a network analyzer to two conductors at one end of the cable. Is done. When the cable includes three or more conductors, the measuring device is connected to any two conductors. The measuring device may be connected to other than the end of the cable, but the high frequency signal is sent to both sides of the connecting part, the spectrum shape becomes complicated, and on which side of the connection position the distortion amount change point exists It is preferable to be connected to the end of the cable or in the vicinity thereof for the reason that it is necessary to determine the above.

  The frequency spectrum of signals such as voltage and power that change due to the magnitude and phase angle of the characteristic impedance and changes in the characteristic impedance is measured in a high frequency band, for example, a band with a lower limit of 1 MHz and an upper limit of 100 to 1500 MHz. Is done. At this time, the number of measurement points of the frequency spectrum may be increased by interpolation using a spline interpolation method or the like to improve the S / N ratio of the time spectrum after inverse Fourier transform.

  According to the present embodiment, the magnitude of the characteristic impedance of the cable in the high frequency band, the phase angle thereof, and the position spectrum of the signal such as voltage and power that change due to the characteristic impedance change are the distortion of the insulated wire or cable. The position of the cable distortion amount change location can be determined by utilizing the change due to the above.

  For example, by obtaining the position spectrum of a signal such as voltage or power that changes due to the magnitude of the characteristic impedance of the installed cable or its phase angle or characteristic impedance change, and comparing the waveform with the waveform of the reference spectrum The position of the portion where the amount of distortion of the cable is changed can be determined. In this case, a state before a change in the amount of distortion caused by bending or compression of the cable, for example, a position spectrum in the initial state of laying the cable can be used as the reference spectrum.

  In the present embodiment, by measuring the frequency spectrum of a signal such as voltage or power that changes due to the magnitude of the characteristic impedance or the phase angle or characteristic impedance change at the end of the cable, and converting it to a position spectrum. Because the position of the distortion amount change location can be determined, even if the distortion amount change location of the cable is located away from the end or at a position separated by a wall, etc. The position of the distortion amount change location can be easily determined. For this reason, the position location method of the distortion amount change location of the insulated wire or cable according to the present embodiment can be used, for example, in a power generation facility such as a nuclear power generation facility or a thermal power generation facility.

  The insulated wire or cable according to the present embodiment is an insulated wire or cable having a first conductor, a second conductor, and an insulator between the first conductor and the second conductor, for example, Vinyl chloride insulated flat type (VFF) cord or coaxial cable. Further, it may be a multi-core cable formed by using a plurality of insulated wires insulated by an organic insulator or the like. The cord refers to a flexible insulated wire.

  Fig.1 (a) is sectional drawing of the insulated flat cord as an example of the insulated wire which concerns on embodiment. FIG. 1B is a cross-sectional view of a three-core cable as an example of the cable according to the embodiment.

  An insulating flat cord 10 such as a VFF (PVC Flat Flexible) cord has a first conductor 11, a second conductor 13, and an insulator 12 that covers the first conductor 11 and the second conductor 13. The first conductor 11 and the second conductor 13 are, for example, tin-plated annealed copper wires. The insulator 12 is made of an insulating material such as polyvinyl chloride or polyethylene. The radius r of the first conductor 11 and the second conductor 13 is, for example, 0.75 mm when 50 strands having a radius of 0.09 mm are twisted, and the center of the first conductor 11 and the second conductor The distance D from the center of the conductor 13 is, for example, 3.1 mm.

  The three-core cable 40 includes a first conductor 41a, a second conductor 41b, and a third conductor 41c, and an insulator 42 that covers the first conductor 41a, the second conductor 41b, and the third conductor 41c, respectively. The pressing tape 43 provided around the first conductor 41a, the second conductor 41b, and the third conductor 41c, the sheath 44 provided around the pressing tape 43, the first conductor 41a, the second And the inclusion 45 filled in the gap between the third conductor 41 c and the third conductor 41 c and the pressing tape 43. The first conductor 41a, the second conductor 41b, and the third conductor 41c are, for example, concentric circular strands of tin-plated copper. The insulator 42 is made of, for example, flame retardant EP rubber. The sheath 43 is made of, for example, special chloroprene. The radii of the first conductor 41a, the second conductor 41b, and the third conductor 41c are, for example, 1.2 mm, the thickness of the insulator 42 is, for example, 0.8 mm, and the thickness of the sheath 44 Is, for example, 1.5 mm.

  FIG. 2 is a cross-sectional view of a coaxial cable as an example of a cable according to the present embodiment.

The coaxial cable 20 includes a first conductor 21, an insulator 22 provided around the first conductor 21, a second conductor 23 provided around the insulator 22, and a second conductor 23. And a jacket 24 provided around the periphery. The first conductor 21 and the second conductor 23 are, for example, a tin-plated annealed copper wire and a tin-plated annealed copper wire braid, respectively. The insulator 22 is made of an insulating material such as polyvinyl chloride or polyethylene. The jacket 24 is made of an insulating material such as polyvinyl chloride. The radius r ₁ of the first conductor 21 is, for example, 0.45 mm, and the outer radius r ₂ of the insulator 22 is, for example, 1.45 mm.

  FIG. 3 is a flowchart showing the flow of the position locating method of the distortion amount changing portion of the insulated wire and cable according to the present embodiment. Below, the insulated flat cord 10 is used as an example of an insulated wire, and the three-core cable 40 and the coaxial cable 20 are used as examples of cables. An example will be described along the flowchart of FIG.

  First, at one end of the insulated flat cord 10 (coaxial cable 20, three-core cable 40), the first conductor 11 and the second conductor 13 (the first conductor 21 and the second conductor 23, or the first conductor 41a). , Two of the second conductor 41b and the third conductor 41c) are connected to a measuring device such as a network analyzer, and the voltage changes due to the magnitude of the characteristic impedance or its phase angle or characteristic impedance change. The frequency spectrum of a signal such as power is measured (step S1). Note that the first conductor 11 and the second conductor 13 (the first conductor 21 and the second conductor 23 or the first conductor are provided at the other end of the insulated flat cord 10 (the coaxial cable 20 and the three-core cable 40). 41a, the second conductor 41b, and the third conductor 41c) may be short-circuited or opened, and may be terminated with an arbitrary resistance or the like.

  Next, the number of measurement points of the frequency spectrum of a signal such as voltage or power that changes due to the magnitude of the characteristic impedance or its phase angle or characteristic impedance change by interpolation is increased (step S2). This step may be omitted.

  Next, the frequency spectrum is converted into a time spectrum which is a spectrum of a function of time by inverse Fourier transform, and further converted into a position spectrum by multiplying by the speed of the electric signal in the insulator (step S3).

  Next, the position of the distortion amount changing portion of the insulated flat cord 10, the coaxial cable 20, or the three-core cable 40 is specified from the obtained waveform of the position spectrum. Specifically, the position spectrum measured in the initial state of the installation of the insulated flat cord 10, the coaxial cable 20, or the three-core cable 40 or the state spectrum before the change of the distortion amount is used as the reference spectrum. By comparing the waveform of the position spectrum of the insulated flat cord 10, the coaxial cable 20, or the three-core cable 40 with the waveform of the reference spectrum, the position of the distortion amount change position can be determined. For example, the position of the distortion amount change position is determined from the peak position of the difference spectrum between the position spectrum of the obtained insulating flat cord 10, the coaxial cable 20, or the three-core cable 40 and the reference spectrum.

(Characteristic impedance)
In general, the electrical properties of insulated wires and cables are expressed by the resistance R and inductance L of conductors connected in series, and the capacitance C and conductance G of insulators connected between the conductors in parallel. The impedance magnitude Z ₀ and its phase angle θ are given by these functions.

The capacitance C and conductance G of the insulator between the conductors are expressed as a function of the relative dielectric constant ε _r and conductivity σ of the insulator between the conductors, but σ is extremely small and G can be regarded as 0. . Also, the characteristic impedance magnitude Z ₀ and the phase angle θ of the insulated wire and cable can be expressed as a function of the relative dielectric constant ε _r of the insulator between the conductors. As an example, the relationship between the characteristic impedance magnitude Z ₀ of the insulating flat cord 10 and the coaxial cable 20 and the relative dielectric constant ε _r of the insulator between the conductors will be described below.

In the insulated flat cord 10, the radius of the first conductor 11 and the second conductor 13 is r, the distance between the center of the first conductor 11 and the center of the second conductor 13 is D, and the permeability of vacuum is μ _0. When the relative permeability of the insulator 12 is μ _r , the dielectric constant of vacuum is ε ₀ , and the relative permittivity of the insulator 12 is ε _r , the inductance L [H / m] per unit length of the insulating flat cord 10 Is approximately expressed as the following Expression 1, assuming that the length is infinite.

  The capacitance C [F / m] per unit length of the insulating flat cord 10 is approximately expressed by the following formula 2 as r << D.

The characteristic impedance magnitude Z ₀ [Ω] in the high frequency region (for example, 1 MHz or more) of the insulating flat cord 10 is approximated by assuming that the resistance R = 0, the conductance G = 0, and the relative permeability μ _r = 1 of the insulator 12. Is expressed as the following Equation 3.

When a change in distortion occurs in the insulated flat cord 10, the distance D between the center of the first conductor 11 and the center of the second conductor 13 mainly changes. As shown in Expression 3, the characteristic impedance magnitude Z ₀ of the insulated flat cord 10 depends on the distance D. Therefore, when the distance D changes due to a change in the amount of distortion, the characteristic impedance magnitude Z ₀ changes.

Therefore, by obtaining the characteristic impedance magnitude Z ₀ , the position of the distortion amount change portion of the insulating flat cord 10 can be determined. Even if the distance D does not change, if the radius r of the first conductor 11 or the second conductor 13 changes to some extent, it is possible to detect the change in the amount of distortion and determine its position.

In the case of measuring the magnitude Z ₀ characteristic impedance of the multi-core cable may be measured by connecting a measurement device such as a network analyzer to the two conductors of which this case, the characteristic impedance magnitude Z ₀ approximately agrees with Equation 3. For example, when measuring the magnitude Z ₀ of the characteristic impedance of the three-core cable 40, a network analyzer or the like is measured on any two of the first conductor 41a, the second conductor 41b, and the third conductor 41c. Connect the equipment and perform the measurement. Then, the characteristic impedance magnitude Z ₀ can be obtained from Equation 3 where D is the distance between the centers of the two conductors connected to the measuring device and r is the radius of each.

  In addition, in the case of a single-core insulated wire, the analytical solution of characteristic impedance cannot be described, but if a measurement circuit is actually connected to a measurement device such as a network analyzer, it can be connected to the feedback line used. Characteristic impedance is determined. Further, when there is no feedback line, an auxiliary line may be arranged so as to constitute a circuit with the target cable, and the characteristic impedance between these lines may be measured. Furthermore, when it is difficult to dispose the auxiliary line, it is also possible to connect only the insulated wire to the measuring device and measure in a so-called open state at the other end.

In the coaxial cable 20, the radius of the first conductor 21 is r ₁ , the outer radius of the insulator 22 is r ₂ , the vacuum permeability is μ ₀ , the relative permeability of the insulator 22 is μ _r , and the vacuum dielectric constant is Assuming that ε ₀ and the relative dielectric constant of the insulator 22 are ε _r , the inductance L [H / m] per unit length of the coaxial cable 20 is approximately expressed by the following equation 4 assuming that the cable length is infinite. It is expressed as follows.

  The electrostatic capacity C [F / m] per unit length of the coaxial cable 20 is expressed by the following Expression 5.

The characteristic impedance magnitude Z ₀ [Ω] in the high-frequency region of the coaxial cable 20 is approximately expressed by the following equation 6 assuming that the resistance R = 0, the conductance G = 0, and the relative permeability μ _r = 1 of the insulator 22. It is expressed as follows.

When a change amount of distortion occurs in the coaxial cable 20, mainly the outer radius r ₂ of the insulator 22 is changed. As shown in Equation 6, the size Z ₀ characteristic impedance of the coaxial cable 20 is dependent on the outer radius r _2, the outer radius r ₂ from the variation of the strain amount changes, the characteristic impedance magnitude Z ₀ Change.

For this reason, by obtaining the characteristic impedance magnitude Z ₀ , the position of the distortion amount changing portion of the coaxial cable 20 can be determined.

In general, when the same external force is applied to the coaxial cable 20, the insulated flat cord 10, and the three-core cable 40, the change in the outer radius r ₂ at the strain amount change point of the coaxial cable 20 In many cases, it is larger than the change in the distance D at the distortion amount change point of 40. For this reason, the coaxial cable 20 can more accurately determine the position of the distortion amount changing portion than the insulated flat cord 10 and the three-core cable 40.

  In general, since the coaxial cable 20 has a smaller signal attenuation than the insulated flat cord 10 and the three-core cable 40, the frequency spectrum can be measured in a high frequency band. For this reason, the position of the distortion amount changing portion can be accurately determined.

[Example 1]
As Example 1, the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the coaxial cable 20 when a distortion is generated by clamping a small region having a length of about 10 mm with a clamp. The change of was measured with a network analyzer.

  First, one end (measurement end) of the coaxial cable 20 having a length of 30 m was connected to a network analyzer. And the frequency spectrum of the power intensity ratio of the incident electromagnetic wave and reflected electromagnetic wave which change resulting from a characteristic impedance change in the frequency band of 1-100 MHz, 1-800 MHz, and 1-1500 MHz was measured. Subsequently, a region of about 5.5 m from the measurement end of the coaxial cable 20 was sandwiched between clamps to generate distortion, and the same measurement was performed.

  Next, the obtained frequency spectrum is converted into a time spectrum which is a spectrum of a function of time by inverse fast Fourier transform, and further multiplied by the speed of the electric signal in the insulator 22 to thereby change the position on the coaxial cable 20. It was converted to a position spectrum which is a function.

  FIG. 4 is a side view schematically illustrating a state when the coaxial cable is clamped according to the first embodiment. In this measurement, the coaxial cable 20 was sandwiched between the clamps 31 so that the diameter in the direction in which force was applied from the clamps 31 at the sandwiched portions (vertical direction in FIG. 4) was about half.

  The first conductor 21 of the coaxial cable 20 used in this measurement is a tin-plated annealed copper wire with a radius of 0.45 mm, the insulator 22 is a layer made of polyethylene with an outer radius of 1.45 mm, and the second The conductor 23 is a tin-plated annealed copper wire braid, and the jacket 24 is a polyvinyl chloride layer having an outer radius of 4 mm.

  FIGS. 5A and 5B show the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that change due to the characteristic impedance change of the coaxial cable in the frequency band of 1 to 100 MHz. FIGS. 6A and 6B show the position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable in the frequency band of 1 to 800 MHz. FIGS. 7A and 7B show the position spectra of the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the characteristic impedance change of the coaxial cable in the frequency band of 1 to 1500 MHz.

  5 (a), 6 (a), and 7 (a) show a reference spectrum (dotted line) that is a spectrum before being clamped and a spectrum (solid line) that is clamped. . FIGS. 5 (b), 6 (b), and 7 (b) show the spectrum and the reference spectrum sandwiched between the clamps shown in FIGS. 5 (a), 6 (a), and 7 (a), respectively. The difference spectrum of is shown.

5 (a), 5 (b), 6 (a), 6 (b) and 7 (a), 7 (b), the horizontal axis indicates the position (m) with respect to the measurement end of the coaxial cable 20. Represent. 5 (a), FIG. 6 (a), and FIG. 7 (a), the vertical axis represents a gain that is ₁₀ log ₁₀ I calculated from the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave (reflected electromagnetic wave power / incident electromagnetic wave power) I. [dB]. In addition, the vertical axis | shaft of FIG.5 (b), FIG.6 (b), and FIG.7 (b) which shows a difference spectrum is described with (DELTA) gain [dB].

  The differential spectrum shown in any of FIGS. 5B, 6B, and 7B has a peak in the vicinity of 5.5 m from the measurement end, and is generated in the coaxial cable 20 by being sandwiched between clamps. It is shown that the distortion is detected.

  5 (b), 6 (b), and 7 (b) show that the peak in the difference spectrum becomes steeper as the frequency band used for the measurement is larger, and the accuracy of the location determination of the distortion amount changing portion of the coaxial cable 20 is increased. Indicates an increase. The peak shown in FIG. 5B has a comparatively gentle shape, and it is difficult to accurately determine the position of the distortion amount changing portion of the coaxial cable 20. On the other hand, the peaks shown in FIG. 6B and FIG. 7B are steep, and it can be confirmed that the amount of distortion at a position 5.5 m from the measurement end of the coaxial cable 20 changes.

  Note that as the length of the portion where the amount of distortion changes is larger, the location of the position where the amount of distortion changes is easier. The measurement results in the present example can be used to determine the position even if the distortion amount changes in a small area of about 10 mm in length by using the method for locating the distortion amount changing portion of the above embodiment. Is shown.

  5 (a), (b), FIGS. 6 (a), (b), and FIGS. 7 (a), (b), the vertical axis indicates the intensity ratio of the incident electromagnetic wave power to the reflected electromagnetic wave power. Although it is a signal, the physical quantity that is the basis of this signal may be a physical quantity that changes due to a change in characteristic impedance, and may be, for example, a voltage or a current. That is, instead of the position spectrum of the intensity ratio between the incident power and the reflected power that changes due to the characteristic impedance change, the position spectrum of the intensity ratio between the incident voltage and the reflected voltage that changes due to the characteristic impedance change, or the characteristic impedance Even when the position spectrum of the intensity ratio of the incident current and the reflected current that changes due to the change is measured, the position of the portion where the distortion amount of the coaxial cable 20 is changed can be similarly determined.

  Next, the clamp was removed from the coaxial cable 20, and the frequency spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changed due to the characteristic impedance change in the frequency band of 1 to 800 MHz was measured with a network analyzer.

  8A and 8B show the positions of the power intensity ratios of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable 20 in the frequency band of 1 to 800 MHz after the clamp is removed. The spectrum is shown.

  FIG. 8A shows a reference spectrum (dotted line) and a spectrum (solid line) with the clamp removed. FIG. 8B shows a difference spectrum between the spectrum and the reference spectrum when about 1 minute has passed since the clamp shown in FIG. 8A was removed.

The horizontal axes in FIGS. 8A and 8B represent the position (m) with the measurement end of the coaxial cable 20 as a reference. The vertical axis of FIG. 8A is a gain [dB] which is ₁₀ log ₁₀ I calculated from the power intensity ratio (reflected electromagnetic wave power / incident electromagnetic wave power) I of the incident electromagnetic wave and the reflected electromagnetic wave. In addition, the vertical axis | shaft of FIG.8 (b) which shows a difference spectrum is described with (DELTA) gain [dB].

  In the differential spectrum shown in FIG. 8B, a peak can be confirmed at a position of about 5.5 m from the measurement end. This indicates that distortion remains even about 1 minute after the clamp is removed. In addition, when a larger distortion occurs in the coaxial cable 20, even after one day has passed since the clamp was removed, the peak corresponding to the distortion can be confirmed in the difference spectrum, and the distortion amount changing portion can be confirmed. The position can be determined.

[Example 2]
As Example 2, the power of the incident electromagnetic wave and the reflected electromagnetic wave that change due to the change in the characteristic impedance of the coaxial cable 20 when the distortion amount is changed by placing it on the L-shaped angle or sandwiching it between the two L-shaped angles. The change in the position spectrum of the intensity ratio was measured with a network analyzer.

  First, one end (measurement end) of the coaxial cable 20 having a length of 30 m was connected to a network analyzer. And the frequency spectrum of the power intensity ratio of the incident electromagnetic wave and reflected electromagnetic wave which change resulting from a characteristic impedance change in the 1-800 MHz frequency band was measured. Subsequently, the coaxial cable 20 was placed on the L-shaped angle so that a portion of about 15.5 m from the measurement end was in contact with the apex of the L-shaped angle, and the same measurement was performed after generating distortion. Further, another L-shaped angle was placed on the coaxial cable 20, and the same measurement was performed after the coaxial cable 20 was sandwiched between the two L-shaped angles. Thereafter, the upper L-shaped angle was removed from the coaxial cable 20 and the same measurement was performed again.

  Next, the obtained frequency spectrum is converted into a time spectrum which is a spectrum of a function of time by inverse fast Fourier transform, and further multiplied by the speed of the electric signal in the insulator 22 to thereby change the position on the coaxial cable 20. It was converted to a position spectrum which is a function.

  FIGS. 9A and 9B are side views schematically showing a state in which the coaxial cable is mounted on an L-shaped angle and a state sandwiched between two L-shaped angles, respectively, according to the second embodiment. When the coaxial cable 20 is sandwiched between the two L-shaped angles 32, the two L-shaped angles 32 are sandwiched and fixed from above and below by a clamp (not shown) in order to maintain the state shown in FIG. 9B. did.

  The configuration of the coaxial cable 20 used in this measurement is the same as the configuration of the coaxial cable 20 used in the measurement of Example 1. The length of one side of the L-shape of the L-shaped angle 32 is 3 cm.

  FIG. 10A shows a reference (dotted line) that is a spectrum before the coaxial cable is placed on the L-shaped angle, and a spectrum (solid line) after the coaxial cable is placed. FIG.10 (b) shows the difference spectrum of the spectrum of the state after mounting the coaxial cable shown by Fig.10 (a) on an L-shaped angle, and a reference spectrum.

  FIG. 11A shows a reference spectrum (dotted line) and a spectrum (solid line) after a coaxial cable is sandwiched between two L-shaped angles. FIG. 11B shows a difference spectrum between a spectrum in a state after the coaxial cable shown in FIG. 11A is sandwiched between two L-shaped angles and a reference spectrum.

  FIG. 12A shows a reference spectrum (dotted line) and a spectrum (solid line) after the coaxial cable is sandwiched between two L-shaped angles and then the upper L-shaped angle is removed. FIG. 12B shows a difference spectrum between the spectrum and the reference spectrum after the upper L-shaped angle is removed after the coaxial cable shown in FIG. 12A is sandwiched between two L-shaped angles.

  Incident electromagnetic waves and reflections that change due to changes in the characteristic impedance of the coaxial cable 20 shown in FIGS. 10 (a), 10 (b), 11 (a), 11 (b), and 12 (a), 12 (b). The position spectrum of the power intensity ratio of the electromagnetic wave is obtained by measuring the frequency spectrum in the frequency band of 1 to 800 MHz.

10 (a), 10 (b), 11 (a), 11 (b), and 12 (a), 12 (b), the horizontal axis represents the position (m) with respect to the measurement end of the coaxial cable 20. Represent. 10 (a), 11 (a), and 12 (a), the vertical axis represents a gain that is ₁₀ log ₁₀ I calculated from the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave (reflected electromagnetic wave power / incident electromagnetic wave power) I. [dB]. In addition, the vertical axis | shaft of FIG.10 (b) which shows a difference spectrum, FIG.11 (b), and FIG.12 (b) is described with (DELTA) gain [dB].

  The difference spectrum shown in any of FIGS. 10 (b), 11 (b), and 12 (b) has a peak in the vicinity of 15.5 m from the measurement end and is placed on an L-shaped angle, It shows that a change in the amount of distortion generated in the coaxial cable 20 is detected in a state of being sandwiched between L-shaped angles or in a state of being sandwiched between two L-shaped angles and then removing the upper L-shaped angle.

  Although the length of the portion where distortion occurs due to the L-shaped angle is considered to be very small, the measurement result in the present example is obtained by using the position location method of the distortion amount changing portion of the above embodiment. This shows that the position can be determined even if the amount of distortion changes in a small area.

  In addition, the vertical axis | shaft of FIG. 10 (a), (b), FIG. 11 (a), (b) and FIG. 12 (a), (b) shows the intensity ratio of the electric power of incident electromagnetic waves, and the electric power of reflected electromagnetic waves. Although it is a signal, the physical quantity that is the basis of this signal may be a physical quantity that changes due to a change in characteristic impedance, and may be, for example, a voltage or a current. That is, instead of the position spectrum of the intensity ratio between the incident power and the reflected power that changes due to the characteristic impedance change, the position spectrum of the intensity ratio between the incident voltage and the reflected voltage that changes due to the characteristic impedance change, or the characteristic impedance Even when the position spectrum of the intensity ratio of the incident current and the reflected current that changes due to the change is measured, the position of the portion where the distortion amount of the coaxial cable 20 is changed can be similarly determined.

Example 3
As Example 3, when the distortion is generated by sandwiching between two L-shaped angles, the ratio of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the characteristic impedance change of the insulating flat cord 10 that is the VFF cord The change of the position spectrum was measured with a network analyzer.

  First, one end (measurement end) of the insulating flat cord 10 having a length of 30 m was connected to a network analyzer. Then, the frequency spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changed due to the characteristic impedance change in the frequency band of 1 to 100 MHz was measured. Subsequently, the same measurement was performed after sandwiching the insulating flat cord 10 at two L-shaped angles so that a portion of about 11 m from the measurement end was in contact with the apex of the lower L-shaped angle.

  Next, the obtained frequency spectrum is converted into a time spectrum which is a spectrum of a function of time by inverse fast Fourier transform, and further multiplied by the speed of the electric signal in the insulator 12 to obtain a position on the insulating flat cord 10. It was converted to a position spectrum that is a function of

FIG. 13 is a side view schematically illustrating a state in which an insulating flat cord is sandwiched between two L-shaped angles according to the third embodiment. In this measurement, the first conductor 11 of the insulated flat cord 10 is easily changed so that the distance D between the center of the first conductor 11 and the center of the second conductor 13 at a position sandwiched between two L-shaped angles is easily changed. And the second conductor 13 are sandwiched between two L-shaped angles in a state of being arranged substantially vertically. As change in the distance D is large, change in the size Z ₀ characteristic impedance of the insulating flat cord 10 becomes large, easy to detect changes in strain.

  The first conductor 11 and the second conductor 13 of the insulated flat cord 10 used for this measurement are conductors having a radius of 0.75 mm in which 50 tin-plated annealed copper wires having a radius of 0.09 mm are twisted. The body 12 is a layer made of polyvinyl chloride, and the distance D between the center of the first conductor 11 and the center of the second conductor 13 is 3.1 mm.

  FIG. 14A shows a reference spectrum (dotted line) that is a state before the insulating flat cord is sandwiched between two L-shaped angles, and a spectrum (solid line) that is sandwiched. FIG. 14B shows a difference spectrum between a spectrum in a state where the insulating flat cord shown in FIG. 14A is sandwiched between two L-shaped angles and a reference spectrum.

  The position spectrum of the power intensity ratio between the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the characteristic impedance change of the insulating flat cord 10 shown in FIGS. 14A and 14B is a frequency spectrum in the frequency band of 1 to 100 MHz. It was obtained by measurement.

14A and 14B, the horizontal axis represents the position (m) with the measurement end of the insulating flat cord 10 as a reference. The vertical axis of FIG. 14A is a gain [dB] that is ₁₀ log ₁₀ I calculated from the power intensity ratio (reflected electromagnetic wave power / incident electromagnetic wave power) I of the incident electromagnetic wave and the reflected electromagnetic wave. In addition, the vertical axis | shaft of FIG.14 (b) which shows a difference spectrum is described with (DELTA) gain [dB].

  The differential spectrum shown in FIG. 14B has a peak in the vicinity of 10 m from the measurement end, and indicates that a change in the amount of distortion generated in the insulated flat cord 10 is detected. If the frequency band of measurement is increased, the positioning accuracy is improved. However, since the spectrum of the insulated flat cord 10 has a larger noise than the spectrum of the coaxial cable 20, it is difficult to determine the position of the distortion amount changing portion. There is a case.

  The vertical axis in FIGS. 14A and 14B uses the intensity ratio between the power of the incident electromagnetic wave and the power of the reflected electromagnetic wave as a signal, but the physical quantity that is the basis of this signal is due to the characteristic impedance change. It may be a physical quantity that changes, for example, a voltage or a current. That is, instead of the position spectrum of the intensity ratio between the incident power and the reflected power that changes due to the characteristic impedance change, the position spectrum of the intensity ratio between the incident voltage and the reflected voltage that changes due to the characteristic impedance change, or the characteristic impedance Even when the position spectrum of the intensity ratio of the incident current and the reflected current that changes due to the change is measured, the position of the portion where the distortion amount of the insulating flat cord 10 is changed can be similarly determined. .

Example 4
As Example 4, the position of the power intensity ratio of the incident electromagnetic wave and the reflected electromagnetic wave that changes due to the change in the characteristic impedance of the three-core cable 40 when distortion is generated by clamping a small region of about 10 mm in length with a clamp The change in spectrum was measured with a network analyzer.

  First, at one end (measurement end) of a 30 m long three-core cable 40, two of the first conductor 41a, the second conductor 41b, and the third conductor 41c were connected to a network analyzer. And the frequency spectrum of the power intensity ratio of the incident electromagnetic wave and reflected electromagnetic wave which change resulting from a characteristic impedance change in the 1-800 MHz frequency band was measured. Subsequently, a region of about 3.5 m from the measurement end of the three-core cable 40 was clamped to generate distortion, and then the same measurement was performed.

  Next, the obtained frequency spectrum is converted into a time spectrum, which is a spectrum of a function of time, by inverse fast Fourier transform, and further multiplied by the speed of the electrical signal in the insulator 42 to thereby obtain a position on the three-core cable 40. It was converted to a position spectrum that is a function of

  The state when the three-core cable 40 is sandwiched between the clamps is the same as the state when the coaxial cable 20 shown in FIG. In this measurement, the three-core cable 40 was clamped so that the diameter in the direction (the vertical direction in FIG. 4) in which force was applied from the clamp at the pinched portion was about 9 mm.

  Note that the first conductor 41a, the second conductor 41b, and the third conductor 41c of the three-core cable 40 used in this measurement are 1.2 mm radius in which seven tin-plated annealed copper wires having a radius of 0.4 mm are twisted. The insulator 42 is a 0.8 mm thick insulator made of flame retardant EP rubber, and the sheath 44 is a 1.5 mm thick layer made of special chloroprene. The diameter is about 13 mm.

  15 (a), (b), FIG. 16 (a), (b), FIG. 17 (a), and (b) are caused by the characteristic impedance change of the three-core cable in the frequency band of 1 to 800 MHz. The position spectrum of the power intensity ratio of the changing incident electromagnetic wave and reflected electromagnetic wave is shown. Here, FIGS. 15A and 15B are spectra when the first conductor 41a and the second conductor 41b are connected to the network analyzer, and FIGS. 16A and 16B are the second conductor. FIGS. 17A and 17B are spectra when the third conductor 41c and the third conductor 41c are connected to the network analyzer. FIGS. 17A and 17B are spectra when the third conductor 41c and the first conductor 41a are connected to the network analyzer. is there.

  FIG. 15A, FIG. 16A, and FIG. 17A show a reference spectrum (dotted line) that is a spectrum before being clamped and a spectrum that is clamped (solid line). . FIGS. 15 (b), 16 (b), and 17 (b) show the spectrum and the reference spectrum sandwiched between the clamps shown in FIGS. 15 (a), 16 (a), and 17 (a), respectively. The difference spectrum of is shown.

15 (a), (b), FIGS. 16 (a), (b), and FIGS. 17 (a), (b), the horizontal axis indicates the position (m) with respect to the measurement end of the three-core cable 40. Represents. 15 (a), 16 (a), and 17 (a), the vertical axis represents a gain that is ₁₀ log ₁₀ I calculated from the power intensity ratio (reflected electromagnetic wave power / incident electromagnetic wave power) I of the incident electromagnetic wave and the reflected electromagnetic wave. [dB]. In addition, the vertical axis | shaft of FIG.15 (b) which shows a difference spectrum, FIG.16 (b), and FIG.17 (b) is described with (DELTA) gain [dB].

  The differential spectra shown in FIGS. 15 (b) and 16 (b) have a peak in the vicinity of 3.5 m from the measurement end where distortion is caused by clamping, but the difference in intensity from the surrounding peaks is small. It is difficult to accurately identify the location of distortion from the spectrum. On the other hand, the differential spectrum shown in FIG. 17 (b) has a peak that is clearly larger than the surrounding peak in the vicinity of 3.5 m from the measurement end, and the distortion generated in the three-core cable 40 due to clamping is clamped. Indicates that it has been detected. This is because the direction in which the force is applied to the three-core cable 40 by the clamp and the direction in which the third conductor 41c and the first conductor 41a are arranged are close to each other, and between the third conductor 41c and the first conductor 41a. This is probably because the distortion was relatively large.

  As can be seen from the results of this example, when the position of the strain amount change portion of the multicore cable is determined, the measurement is repeated while changing the conductor connected to the measuring device such as a network analyzer, thereby improving the accuracy of the orientation. be able to.

  15 (a), (b), FIGS. 16 (a), (b), and FIGS. 17 (a), 17 (b), the vertical axis indicates the intensity ratio of the incident electromagnetic wave power to the reflected electromagnetic wave power. Although it is a signal, the physical quantity that is the basis of this signal may be a physical quantity that changes due to a change in characteristic impedance, and may be, for example, a voltage or a current. That is, instead of the position spectrum of the intensity ratio between the incident power and the reflected power that changes due to the characteristic impedance change, the position spectrum of the intensity ratio between the incident voltage and the reflected voltage that changes due to the characteristic impedance change, or the characteristic impedance Even when the position spectrum of the intensity ratio of the incident current and the reflected current that changes due to the change is measured, the position of the portion where the strain amount of the three-core cable 40 is changed can be similarly determined. .

  Although the embodiments and examples of the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the invention.

  The embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

DESCRIPTION OF SYMBOLS 10 Insulated flat cord 11, 21, 41a 1st conductor 12, 22, 42 Insulator 13, 23, 41b 2nd conductor 20 Coaxial cable 24 Jacket 31 Clamp 32 L-shaped angle 40 3 core cable 41c 3rd conductor

Claims (8)

A method of locating a strain change point of an insulated wire or cable having a conductor and an insulator,
Measuring the frequency spectrum of the signal that changes due to the magnitude of the characteristic impedance of the insulated wire or cable or its phase angle or characteristic impedance change;
Transforming the frequency spectrum into a position spectrum that is a function of position on the insulated wire or cable;
The step of locating the position of the amount of strain change on the insulated wire or cable from the waveform of the position spectrum;
Method for locating a distortion amount change portion of an insulated wire or cable including The conductor includes a first conductor and a second conductor, and at least a portion of the insulator is located between the first conductor and the second conductor;
The position location method of the distortion amount change location of the insulated wire or cable of Claim 1. The frequency spectrum is converted to a time spectrum that is a spectrum of a function of time by inverse Fourier transform, and further converted to the position spectrum by multiplying by the speed of an electric signal in the insulator.
The position location method of the distortion amount change location of the insulated wire or cable of Claim 1 or 2. By comparing the waveform of the position spectrum and the waveform of the position spectrum in a state before the change of the distortion amount of the insulated wire or cable occurs, the position of the distortion amount change location is determined.
The position location method of the distortion amount change location of the insulated wire or cable of any one of Claims 1-3. The position of the distortion change location of the coaxial cable as the cable is determined,
The position location method of the distortion amount change location of the insulated wire or cable of any one of Claims 1-4. The position of the strain amount change point of the insulated flat cord as the insulated wire is determined,
The position location method of the distortion amount change location of the insulated wire or cable of any one of Claims 1-4. The position of the strain amount change point of the multicore cable as the cable is determined,
The position location method of the distortion amount change location of the insulated wire or cable of any one of Claims 1-4. After increasing the number of measurement points of the frequency spectrum by interpolation, the frequency spectrum is converted to the position spectrum,
The position location method of the distortion amount change location of the insulated wire or cable of any one of Claims 1-7.

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