JP7406170B2 - Measurement system and measurement method - Google Patents

Description

The present invention relates to a measurement system and a measurement method.

Electromagnetic noise in the same frequency band as signals used for communication enters communication equipment via power cables and communication cables, causing communication failures in communication equipment. For example, electromagnetic noise of several hundred kHz to several MHz generated from a quick charger of an electric vehicle may interrupt ADSL communication in the same frequency band.

Electromagnetic noise is an electrical signal that cannot be seen with the naked eye, and the cause of communication failure due to electromagnetic noise cannot be identified visually, such as when a cable breaks. Therefore, when a communication failure suspected to be caused by electromagnetic noise occurs, maintenance personnel use measuring instruments such as oscilloscopes to measure the intensity and frequency of the electromagnetic noise flowing through the cable. At that time, the electromagnetic noise often forms a loop with the earth or a large conductor connected to the earth (hereinafter referred to as earth) as the return path. Measures the ground voltage of electromagnetic noise flowing through the target cable.

Normally, the ground voltage of electromagnetic noise is measured by grounding the measuring instrument used and touching or clamping the measuring instrument's passive probe or capacitive voltage probe (see Non-Patent Document 1) to the cable to be measured. be done. On the other hand, if it is difficult to ground the measuring instrument, measure the ground voltage of electromagnetic noise without grounding the measuring instrument, and also use a ground capacity measuring mechanism (non-ground capacitance measuring mechanism) installed at the same altitude as the measuring instrument. (see Patent Document 2), the ground capacity of a measuring device is indirectly measured. Then, by correcting the ground voltage of the electromagnetic noise with an error measured by the measuring device using the ground capacity of the measuring device measured by the ground capacitance measurement mechanism, an accurate ground voltage of the electromagnetic noise is obtained (Non-patent Document (See 3).

Ryuichi KOBAYASHI, 5 others, “A Novel Non-contact Capacitive Probe for Common-Mode Voltage Measurement”, IEICE TRANS. COMMUN., VOL.E90-B, NO.6, DOI: 10.1093/ietcom/e90-b.6.1329 , June 2007, p.1329-p.1337 Minoruto Arai and two others, “Proposal of a method for estimating ground capacitance for simple grounding of measuring instruments”, March 19-22, 2019, IEICE General Conference, B-4- 44, Correspondence lecture collection 1, p.264 Naruto ARAI, and 3 others, “Measuring Conducted Noise Voltage with a Floating Measurement System to Ground”, IEICE TRANSACTIONS on Communications, DOI:10.1587/transcom.2019MCP0001, The Institute of Electronics, Information and Communication Engineers, April 2020 8th, p.1-p.9

By using the techniques disclosed in Non-Patent Documents 2 and 3, it is possible to accurately measure the ground voltage of electromagnetic noise even when the measuring device is not grounded. However, the ground capacitance C formed between the conductor plate connected to the ground line of the measuring instrument and the earth, and the ground capacitance C of the electrode of the ground capacitance measuring mechanism are respectively the area S of the conductor plate or electrode, and the area S of the conductor plate Alternatively, it is assumed that the thickness d _k and relative dielectric constant ε _k of the substance existing between the electrode and the ground are expressed by equation (1). Note that ε ₀ is an electrical constant. N is the total number of material layers present between the electrode and the ground.

However, if the measurement location where the measuring device and ground capacity measurement mechanism are installed is far from the ground, Equation (1) does not hold, so accurate ground capacitance of the measuring device cannot be obtained, and electromagnetic noise There was a problem in that the voltage could not be corrected by the ground capacity of the accurate measuring device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for measuring the ground voltage of electromagnetic noise using a non-grounded measuring device, and to improve the relationship between the measurement location where the measuring device is installed and the ground. An object of the present invention is to provide a technology that can accurately measure the ground voltage of electromagnetic noise even when there is a large distance between the two.

A measuring system according to one aspect of the present invention includes a measuring device that measures the ground voltage of electromagnetic noise without grounding a ground line, and a measuring device that is used to correct an error in the ground voltage of the electromagnetic noise, and that is used to correct an error in the ground voltage of the electromagnetic noise. A measurement system comprising a correction device that measures a fluctuating voltage that changes depending on the size of a capacitance, and a calculation device communicably connected to the measurement device and the correction device, respectively, the calculation device comprising: In a state where the measuring device and the correction device are each installed on a dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the correction device and the electromagnetic noise are a generation unit that generates a list that is used to correct errors in ground voltage and that associates values of correction data measured by the measuring device based on pseudo-electromagnetic noise; the measuring device and the correction device; and are installed at electromagnetic noise measurement locations, obtain the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device from the list, and obtain the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device, and A correction unit that corrects the ground voltage of electromagnetic noise using the value of the correction data.

A measuring method according to one aspect of the present invention includes a measuring device that measures the ground voltage of electromagnetic noise without grounding a ground line, and a measuring device that is used to correct an error in the ground voltage of the electromagnetic noise, and a self-correction device that measures the ground voltage of electromagnetic noise. A measurement method using a correction device that measures a fluctuating voltage that changes depending on the size of a capacitance, and an arithmetic device that is communicably connected to the measuring device and the correction device, respectively, the arithmetic device comprising: , in a state where the measuring device and the correction device are respectively installed on a dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the correction device and the electromagnetic noise are a step of generating a list in which the values of correction data measured by the measuring device based on pseudo electromagnetic noise are related to each other, the measuring device and the correcting device and are installed at electromagnetic noise measurement locations, obtain the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device from the list, and obtain the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device, and and correcting the ground voltage of electromagnetic noise using the value of the correction data.

According to the present invention, in a method of measuring the ground voltage of electromagnetic noise with an ungrounded measuring instrument, electromagnetic noise We can provide technology that can accurately measure the ground voltage of

FIG. 1 is a graph showing the ground capacity of a conductor plate versus the thickness of an acrylic plate. FIG. 2 is a diagram showing an equivalent circuit when measuring the ground voltage of electromagnetic noise with a non-grounded measuring device. FIG. 3 is a diagram showing the configuration of the correction device. FIG. 4 is a diagram showing an equivalent circuit of the correction device. FIG. 5 is a diagram showing the configuration of the measurement system during preliminary work. FIG. 6 is a diagram showing a processing flow of preliminary work in the first embodiment. FIG. 7 is a diagram showing a processing flow of measurement work in the first embodiment. FIG. 8 is a diagram showing a processing flow of preliminary work in the second embodiment. FIG. 9 is a diagram showing a processing flow of measurement work in the second embodiment. FIG. 10 is a diagram showing the hardware configuration of the arithmetic device.

Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals and explanations will be omitted.

[Summary of the invention]
The present invention relates to a method for easily measuring electromagnetic noise generated in power cables and metal communication cables. As already explained, if the measurement location where the measuring device and ground capacity measuring mechanism are installed is far from the ground, equation (1) does not hold. For example, when a 250 mm x 120 mm first conductor plate is placed on a large second conductor plate with an acrylic plate in between, the capacitance between the first conductor plate and the second conductor plate, that is, the capacitance between the first conductor plate and the second conductor plate is Figure 1 shows the ground capacity of the board.

The triangular plot in FIG. 1 is the first ground capacitance C1 of the first conductor plate determined by electromagnetic field analysis. The circle plot is the second ground capacitance C2 of the first conductor plate assuming that equation (1) holds. The square plots and the line connecting the square plots are graphs showing how many times the second ground capacity C2 is the first ground capacity C1. The scale of the triangular plot and the round plot is the scale on the left, and the scale of the square plot and the line connecting the square plots is the scale on the right.

In FIG. 1, the square plots and the line connecting the square plots gradually move away from 1 as the thickness of the acrylic plate increases. This indicates that the ground capacity model of equation (1) does not hold if the measurement location where the measuring device and ground capacity measurement mechanism are installed is far from the ground.

Therefore, in the present invention, formula (1) is not used, and a correction list for correcting the ground voltage of electromagnetic noise is generated in advance, and the correction list is generated in advance to correct the ground voltage of electromagnetic noise. The problem is solved by correcting the ground voltage of electromagnetic noise with accurate errors using the correction list.

Specifically, the inaccurate ground voltage of electromagnetic noise measured with an ungrounded measuring device at the electromagnetic noise measurement location is corrected using the ground capacitance of the conductor plate connected to the ground wire of the measuring device. A method (Example 1) and a method of correcting using a predetermined correction coefficient (Example 2) are disclosed. Note that the present invention also uses a device having the same configuration as the "ground capacity measurement mechanism" used in the prior art, but since the present invention does not use ground capacity, the device is referred to as a "correction device."

For example, in the preliminary work, the measurement results measured by the correction device (fluctuation voltage that changes depending on the ground capacity of the correction device) and the grounding of the conductor plate connected to the ground line of the measuring device in Example 1. In the second embodiment, a list is created in association with the capacity, and in the second embodiment, a correction coefficient. Then, at the measurement location, the inaccurate ground voltage of electromagnetic noise measured with an ungrounded measuring instrument is corrected using the ground capacitance of the conductor plate or correction coefficient corresponding to the measurement result (fluctuation voltage) measured by the correction device. .

Since the present invention does not use equation (1), the problem that equation (1) does not hold does not occur, and the distance between the measurement location where the measuring device and ground capacity measurement mechanism are installed and the ground is increased. It is possible to measure the ground voltage of electromagnetic noise with high accuracy even in the case of

[Measuring instrument]
FIG. 2 is a diagram showing an equivalent circuit when measuring the ground voltage of electromagnetic noise with the measuring instrument 1 in an ungrounded state. During measurement, a conductive plate is connected to the ground wire of the measuring device 1 with a copper wire or the like, and the measuring device 1 is installed on the conductive plate. V _n is the ground voltage of the electromagnetic noise to be measured. Z _n is the equivalent electromagnetic noise load impedance. Z _m is the input impedance of the measuring instrument 1. V _m is the ground voltage of electromagnetic noise measured by the measuring device 1. C _m is the ground capacitance of the conductor plate connected to the ground line of the measuring instrument 1. At this time, since Z _n is generally a small value, the ground voltage V _m of electromagnetic noise measured by the measuring device 1 is expressed by equation (2). Note that ω _n is the angular frequency of electromagnetic noise. j is an imaginary unit.

From equation (2), the ground voltage V _m of the electromagnetic noise measured by the measuring device 1 is the ground voltage of the electromagnetic noise to be measured, based on the ground capacitance C _m of the conductor plate connected to the ground wire of the measuring device 1. V _n becomes smaller. Therefore, in Example 1, the ground capacity C _m is calculated from the correction list generated in advance, and the ground capacity C _m is substituted into equation (3) obtained by converting equation (2) to solve the problem. The voltage to ground V _m of the electromagnetic noise measured in step 1 is corrected to the voltage to ground V _n of the electromagnetic noise to be measured.

In Example 2, the correction _coefficient The voltage to ground of the electromagnetic noise is corrected to V _n . In addition, in the second embodiment, it is not necessary to determine the ground capacitance C _m of the conductor plate connected to the ground line of the measuring instrument 1.

[Example 1]
Example 1 will be explained.

FIG. 3 is a diagram showing the configuration of the correction device 2. As shown in FIG. The correction device 2 includes a voltage measurement circuit 21, an oscillation circuit 22, a first electrode 23a, a second electrode 23b, a third electrode 23c, a first spacer 24a, and a second spacer 24b. The first electrode 23a and the second electrode 23b are spaced apart and arranged at the same altitude, and are arranged opposite to the third electrode 23c with the first spacer 24a in between. Voltage measurement circuit 21 and oscillation circuit 22 are connected in series. Each end of the voltage measurement circuit 21 is connected to a first electrode 23a and a third electrode 23c, respectively. Each end of the oscillation circuit 22 is connected to a second electrode 23b and a third electrode 23c, respectively. The second spacer 24b is arranged under the first electrode 23a and the second electrode 23b.

FIG. 4 is a diagram showing an equivalent circuit of the correction device 2 including the ground. When a signal is output from the oscillation circuit 22, a voltage _Vr is generated in the voltage measurement circuit 21. If the input impedance of the voltage measurement circuit 21 is designed to be sufficiently large, the voltage V _r is expressed by equation (5).

Note that V _out is the output voltage of the oscillation circuit 22. R _out is the output resistance of the oscillation circuit 22. C ₁ is the ground capacitance of the first electrode 23a. C ₂ is the ground capacitance of the second electrode 23b. _C3 is the ground capacitance of the third electrode 23c. _C4 is the capacitance between the first electrode 23a and the third electrode 23c. _C5 is the capacitance between the second electrode 23b and the third electrode 23c. ω is the angular frequency of the signal output from the oscillation circuit 22.

Equation (5) shows that the voltage V _r changes depending on the values of C ₁ , C ₂ , and C ₃ . For example, when the values of C ₁ , C ₂ , and C ₃ are small, that is, when the distance between the correction device 2 and the earth is large, or the relative dielectric constant of the material between the correction device 2 and the earth When V r is small, the voltage V _r has a small value.

Using this correction device 2, in order to obtain the ground capacitance C _m (see Fig. 2) of the conductor plate connected to the ground line of the measuring instrument 1 at the electromagnetic noise measurement location, the voltage V _r of the correction device 2 and , and the ground capacitance C _m of the conductor plate connected to the ground line of the measuring instrument 1 must be determined in advance. This preliminary work will be explained below.

FIG. 5 is a diagram showing the configuration of the measurement system during preliminary work. A dielectric board 4 such as an acrylic board or wood is placed on a shield room floor 3 serving as a large conductor, and a correction device 2 is placed on it. Next, a signal generator 5 that outputs a sine wave with a voltage of 2V _nt and an angular frequency ω _nt is connected to the shield room floor 3 through a resistor 6 having the same size as the output impedance of the signal generator 5 . This operation is an operation for causing the resistor 6 to generate a voltage V _nt corresponding to the ground voltage V _n of the electromagnetic noise to be measured. Next, the ground line of the measuring instrument 1 is connected to the conductor plate 7, and the conductor plate 7 is placed on the dielectric plate 4. The measuring device 1 is placed on the conductor plate 7. Thereby, the heights of the correction device 2 and the conductor plate 7 become equal. Finally, the arithmetic device 8 is connected to the measuring instrument 1, the correction device 2, and the signal generating device 5, respectively, so as to be communicable by wire or wirelessly.

In the measurement system of FIG. 5, the measuring device 1 measures the ground voltage V _m of electromagnetic noise without grounding the ground line. The correction device 2 is used to correct the error in the ground voltage V _m of electromagnetic noise measured by the measuring device 1, and changes depending on the magnitude of the ground capacitance C ₁ , C ₂ , C ₃ of the correction device 2. , measure the varying voltage V _r . The calculation device 8 calculates the ground capacitance C _m of the conductor plate connected to the ground line of the measuring device 1 using the ground voltage V _m of the electromagnetic noise measured by the measuring device 1 and the voltage V _n generated in the resistor 6. Then, the correspondence relationship between the voltage V _r of the correction device 2 and the ground capacitance C _m of the conductor plate connected to the ground line of the measuring device 1 is listed. The calculation device 8 includes, for example, a generation unit 81 that functions during preliminary work, a correction unit 82 that functions during measurement work at a measurement location, and a storage unit 83 that stores various data such as measurement results.

The generation unit 81 generates the value of the voltage Vr measured by the correction device 2 each time the thickness of the dielectric plate 4 is changed in a state where the measuring device 1 and the correction device 2 are respectively installed on the _dielectric plate 4. and the correction measured by the measuring device 1 based on the signal as the pseudo electromagnetic noise output from the signal generator 5, which is used to correct the error in the ground voltage V _m of the electromagnetic noise measured by the measuring device 1. The storage unit 83 has a function of generating a list that associates the value of the data with the data and storing it in the storage unit 83.

The correction unit 82 stores the value of the correction data corresponding to the value of the voltage V _r measured by the correction device 2 in the storage unit in a state where the measuring device 1 and the correction device 2 are respectively installed at the electromagnetic noise measurement location. It has a function of correcting the ground voltage V _m of electromagnetic noise obtained from the list of 83 and measured by the measuring instrument 1 with the value of the correction data.

In the first embodiment, the value of the correction data is the ground capacitance of the conductive plate 7 connected to the ground line of the measuring device 1 and installed on the dielectric plate 4. In Example 2, which will be described later, the value of the correction data means that by multiplying the voltage to ground V _m of electromagnetic noise measured by the measuring device 1, it is possible to obtain the voltage to ground V _n of electromagnetic noise after correction. This is a correction coefficient. Specifically, it is the ratio between the voltage V _n generated in the resistor 6 by the signal output from the signal generator 5 and the ground voltage V _m of the electromagnetic noise measured by the measuring device 1 .

FIG. 6 is a diagram showing a processing flow of preliminary work in the first embodiment.

Step S101;
First, the correction device 2 measures the voltage _Vr . The correction device 2 transmits the measurement result of the voltage V _r to the calculation device 8 . Arithmetic device 8 stores the measurement results of voltage _Vr .

Step S102;
Next, the signal generator 5 outputs a sine wave with a voltage of 2V _nt . The signal generator 5 transmits a voltage value of V _nt which is 1/2 of the voltage 2V _nt to the arithmetic unit 8 . The measuring device 1 measures the voltage V _mt generated across the resistor 6 using a probe 11 connected to the measuring device 1 (see FIG. 5). The measuring device 1 transmits the measurement result of the voltage V _mt to the arithmetic device 8 . Arithmetic device 8 stores voltage V _nt and voltage V _mt .

Step S103;
Next, the arithmetic unit 8 calculates the conductor connected to the ground line of the measuring instrument 1 by substituting the voltage V _nt and the voltage V _mt into equation (6) for calculating the ground capacitance C _m and solving it. Find the ground capacity C _m of the plate. Note that Z _m is the input impedance of the measuring instrument 1 including the probe 11, and is a value described in the data sheets of the measuring instrument 1 and the probe 11.

Thereafter, the calculation device 8 generates a list that associates the voltage V _r of the correction device 2 with the ground capacitance C _m of the conductor plate connected to the ground line of the measuring device 1 . If the list has already been generated, the arithmetic device 8 adds the correspondence between the voltage V _r and the ground capacitance C _m to the next line of the list.

Step S104;
Next, the arithmetic device 8 or the measurer determines whether the above-mentioned measurement has been performed for all the thicknesses of the dielectric plates 4. If the above measurement has not been performed for all the thicknesses of the dielectric plates 4, the process advances to step S105. When the above measurements have been performed for all the thicknesses of the dielectric plates 4, the process ends.

Step S105;
Next, the computing device 8 or the measurer changes the thickness of the dielectric plate 4. After that, the process returns to step S101.

Thereafter, steps S101 to S103 are repeatedly executed while changing the thickness of the dielectric plate 4. Thereby, the arithmetic unit 8 can list the correspondence between the voltage Vr and the ground capacitance _Cm according to the thickness of the dielectric plate 4. The thickness of the dielectric plate 4 can be changed by, for example, manually by a measurer, or automatically by connecting a link mechanism to the arithmetic device 8.

Next, the measurement work at the electromagnetic noise measurement location will be explained.

FIG. 7 is a diagram showing a processing flow of measurement work at a measurement location in the first embodiment. At the electromagnetic noise measurement location, the measuring device 1, the conductor plate 7, the correction device 2, and the arithmetic device 8 are installed in the same manner as in FIG. The dielectric plate 4 in FIG. 5 is the location where electromagnetic noise is measured.

Step S201;
First, the correction device 2 measures the voltage _Vr at the electromagnetic noise measurement location. The correction device 2 transmits the measurement result of the voltage V _r to the calculation device 8 .

Step S202;
Next, the calculation device 8 calculates the ground capacity C of the conductor plate connected to the ground wire of the measuring instrument 1, which corresponds to the voltage V _r of the correction device 2 at the electromagnetic noise measurement location, from the list created in advance. Select _m .

Step S203;
Next, the measuring device 1 measures the ground voltage V _m of the electromagnetic noise at the electromagnetic noise measurement location. The measuring device 1 transmits the measurement result of the ground voltage V _m to the arithmetic device 8 .

Step S204;
Finally, the correction device 2 obtains the ground voltage V _n of the electromagnetic noise by substituting the ground capacitance C _m and the ground voltage V _m into equation (3) and solving it. That is, the ground voltage V _m of electromagnetic noise with an error measured by the measuring device 1 is corrected to the ground voltage V _n of the electromagnetic noise to be measured. The ground voltage V _n of electromagnetic noise is displayed on the monitor of the correction device 2 . At this time, V _n may be displayed as an intensity for each frequency or as a waveform of electromagnetic noise. This is because since the correction is performed using the ground capacity C _m , not only the intensity but also the phase information can be corrected.

[Example 2]
Next, Example 2 will be explained.

Embodiment 2 differs from Embodiment 1 in that, in the preliminary work, the correction coefficient X is determined instead of determining the correspondence between the voltage Vr and the ground capacitance _Cm . Further, in the second embodiment, unlike the first embodiment, the signal generator 5 outputs sine waves of M different frequencies from the angular frequency ω _nt1 to the angular frequency ω _ntM instead of a single frequency. The magnitude of the voltage output from the signal generator 5 is constant at 2V _nt as in the first embodiment. The overall configuration of the measurement system and the mechanisms of the measuring device 1, correction device 2, etc. are also the same as in the first embodiment. The preliminary work will be explained below.

FIG. 8 is a diagram showing a processing flow of preliminary work in the second embodiment.

Step S301;
First, the correction device 2 measures the voltage _Vr . The correction device 2 transmits the measurement result of the voltage V _r to the calculation device 8 . Arithmetic device 8 stores the measurement results of voltage _Vr .

Step S302;
Next, the signal generator 5 outputs a sine wave with a voltage of 2V _nt and an angular frequency ω _{ntk (k=1)} . The signal generator 5 transmits a voltage value of V _nt which is 1/2 of the voltage 2V _nt to the arithmetic unit 8 . The measuring device 1 measures the voltage V _{mtk (k=1)} generated across the resistor 6 using a probe 11 connected to the measuring device 1 . The measuring device 1 transmits the measurement result of the voltage V _{mtk (k=1)} to the arithmetic device 8 . Arithmetic device 8 stores voltage V _nt and voltage V _{mtk (k=1)} .

Step S303;
Next, the arithmetic unit 8 calculates the correction coefficient X at the angular frequency ω _{ntk (} k=1) by substituting the voltage V _nt and the voltage V _{mtk (k=1)} into equation (7) and solving it. .

Step S304;
Next, the arithmetic device 8 determines whether k=M. If k=M is not true, the process advances to step S305. If k=M, the process advances to step S306.

Step S305;
Next, the arithmetic device 8 sets k=k+1 and returns to step S302.

Thereafter, the signal generator 5 outputs a sine wave with a voltage of 2V _nt and an angular frequency ω _{ntk (k=2)} . Furthermore, the calculation device 8 calculates the correction coefficient X at the angular frequency ω _{ntk (k=2)} . This process is repeated until the angular frequency ω _ntk becomes the angular frequency ω _ntM .

Step S306;
Next, the arithmetic device 8 generates a list that associates the voltage V _r of the correction device 2 with each correction coefficient X at each angular frequency ω _ntk . If the list has already been generated, the arithmetic unit 8 adds the correspondence between the voltage V _r and each correction coefficient X at each angular frequency ω _ntk to the next line of the list.

Step S307;
Next, the arithmetic device 8 or the measurer determines whether the above-mentioned measurement has been performed for all the thicknesses of the dielectric plates 4. If the above measurement has not been performed for all the thicknesses of the dielectric plates 4, the process advances to step S308. When the above measurements have been performed for all the thicknesses of the dielectric plates 4, the process ends.

Step S308;
Next, the computing device 8 or the measurer changes the thickness of the dielectric plate 4. After that, the process returns to step S301.

Thereafter, steps S301 to S306 are repeatedly executed while changing the thickness of the dielectric plate 4. Thereby, the calculation device 8 can list the correspondence between the thickness of the dielectric plate 4, the voltage Vr, and each correction coefficient X at each angular frequency ω _ntk .

Next, the measurement work at the electromagnetic noise measurement location will be explained.

FIG. 9 is a diagram showing a processing flow of measurement work at a measurement location in Example 2.

Step S401;
First, the correction device 2 measures the voltage _Vr at the electromagnetic noise measurement location. The correction device 2 transmits the measurement result of the voltage V _r to the calculation device 8 . Note that the voltage V _r can be decomposed into each angular frequency ω _ntk .

Step S402;
Next, the correction device 2 selects all M correction coefficients X corresponding to the voltage V _r of the correction device 2 at the electromagnetic noise measurement location from the list created in the preliminary work.

Step S403;
Next, the measuring device 1 measures the ground voltage V _m of the electromagnetic noise at the electromagnetic noise measurement location. The measuring device 1 transmits the measurement result of the ground voltage V _m to the arithmetic device 8 .

Step S404;
Finally, the correction device 2 obtains the ground voltage V _n of the electromagnetic noise at each angular frequency ω _ntk by substituting each correction coefficient X and the ground voltage V _m into Equation (4) and solving the equation. That is, the ground voltage V _m of electromagnetic noise with an error measured by the measuring device 1 is corrected to the ground voltage V _n of the electromagnetic noise to be measured. The ground voltage V _n of electromagnetic noise is displayed on the monitor of the correction device 2 . At this time, V _n is displayed as intensity for each frequency.

As described above, the newly invented measurement method makes it possible to accurately measure the ground voltage of electromagnetic noise in an ungrounded state even when the distance between the measurement location and the ground is large. The reason for this is that the list for correction is created in advance without using equation (1), which is the premise of the prior art.

[Effects of Examples]
In Embodiment 1, in advance work, a correction list is created in which the ground capacitance C _m of the conductor plate 7 connected to the ground line of the measuring instrument 1 is associated with the measurement results of the correction device 2, and the list is prepared at the measurement site. Using this list, find the ground capacitance C _m of the conductor plate 7 connected to the ground line of the measuring device 1 from the measurement results of the correction device 2, and with the ground capacitance C _m , the electromagnetic capacitance measured by the measuring device 1 A method for correcting the ground voltage V _m of noise has been explained.

In Example 2, in the _preliminary work, the _correction coefficient Create an associated correction list, use this list at the measurement site to find the correction coefficient X from the measurement results of the correction device 2, and use the correction coefficient The method for correcting the ground voltage V _m has been explained.

The method of the second embodiment has higher measurement accuracy than the first embodiment because data of all frequency bands to be measured are acquired in advance. On the other hand, in Example 1, since it is only necessary to acquire data of a single frequency in the preliminary work, the time required for the preliminary work can be reduced compared to Example 2, and furthermore, it is possible to correct not only the intensity but also the phase. Therefore, it is possible to display the measurement results as a waveform.

As described above, according to the present embodiment, there is provided a measuring device 1 that measures the ground voltage of electromagnetic noise without grounding the ground wire, and a self-correction device that is used to correct the error in the ground voltage of the electromagnetic noise. A measurement system comprising a correction device 2 that measures a fluctuating voltage that changes depending on the magnitude of ground capacitance, and an arithmetic device 8 that is communicably connected to the measuring device 1 and the correction device 2, respectively. The arithmetic device 8 calculates the measurement result by the correction device 2 each time the thickness of the dielectric plate 4 is changed in a state where the measuring device 1 and the correction device 2 are respectively installed on the dielectric plate 4. A list is generated that associates the value of the fluctuating voltage with the value of correction data that is used to correct an error in the ground voltage of the electromagnetic noise and is measured by the measuring device based on the pseudo electromagnetic noise. The generation unit 81, the measuring device 1, and the correction device 2 are each installed at a place where electromagnetic noise is measured, and the correction data corresponding to the value of the fluctuating voltage measured by the correction device 2 is generated. The correction unit 82 acquires the value from the list and corrects the ground voltage of the electromagnetic noise measured by the measuring device 1 with the value of the correction data, so that the measurement location where the measuring device 1 is installed and the ground are corrected. It is possible to provide a technology that can accurately measure the ground voltage of electromagnetic noise even when there is a large distance between the ground and the ground.

[others]
Note that the present invention is not limited to the above embodiments. The present invention is capable of numerous modifications within the scope of the invention.

The arithmetic device 8 of this embodiment described above includes, for example, a CPU (Central Processing Unit, processor) 901, a memory 902, and a storage (HDD: Hard Disk Drive, SSD: Solid State Drive), as shown in FIG. This can be realized using a general-purpose computer system including a communication device 903, a communication device 904, an input device 905, and an output device 906. Memory 902 and storage 903 are storage devices. In the computer system, each function of the arithmetic device 8 is realized by the CPU 901 executing a predetermined program loaded onto the memory 902.

Arithmetic device 8 may be implemented by one computer. Arithmetic device 8 may be implemented with multiple computers. The arithmetic device 8 may be a virtual machine implemented in a computer. The program for the arithmetic device 8 can be stored in a computer-readable recording medium such as an HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc). The program for the computing device 8 can also be distributed via a communication network.

1: Measuring instrument 11: Probe 2: Correction device 21: Voltage measurement circuit 22: Oscillation circuit 23a: First electrode 23b: Second electrode 23c: Third electrode 24a: First spacer 24b: Second spacer 3: Shield room floor 4: Dielectric plate 5: Signal generator 6: Resistor 7: Conductor plate 8: Arithmetic unit 81: Generation section 82: Correction section 83: Storage section 901: CPU
902: Memory 903: Storage 904: Communication device 905: Input device 906: Output device

Claims (5)

A measuring device that measures the ground voltage of electromagnetic noise without grounding the ground wire, and a variation that is used to correct the error in the ground voltage of the electromagnetic noise and that changes depending on the ground capacity of the self-correction device. A measurement system comprising a correction device that measures voltage, and an arithmetic device communicably connected to the measuring device and the correction device, respectively,
The arithmetic device is
In a state where the measuring device and the correction device are each installed on a dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the correction device and the electromagnetic noise are A generation unit that generates a list that is used to correct errors in ground voltage and that associates values of correction data measured by the measuring device based on pseudo electromagnetic noise;
In a state where the measuring device and the correction device are each installed at a place where electromagnetic noise is measured, acquiring the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device from the list, a correction unit that corrects the ground voltage of electromagnetic noise measured by the measuring device using the value of the correction data;
A measurement system equipped with. The correction data is
2. The measurement system according to claim 1, wherein the ground capacitance is a ground capacity of a conductor plate connected to a ground line of the measuring device and installed on the dielectric plate. The correction data is
2. The measurement system according to claim 1, wherein the correction coefficient is a correction coefficient that can obtain the corrected electromagnetic noise ground voltage by multiplying the ground voltage of the electromagnetic noise measured by the measuring device. The correction coefficient is
4. The measurement system according to claim 3, which is a ratio between the voltage of the pseudo electromagnetic noise output from the signal generator and the voltage of the pseudo electromagnetic noise measured by the measuring device. A measuring device that measures the ground voltage of electromagnetic noise without grounding the ground wire, and a variation that is used to correct the error in the ground voltage of the electromagnetic noise and that changes depending on the ground capacity of the self-correction device. A measurement method using a correction device that measures voltage, and an arithmetic device communicably connected to the measuring device and the correction device, respectively,
The arithmetic device is
In a state where the measuring device and the correction device are each installed on a dielectric plate, each time the thickness of the dielectric plate is changed, the value of the fluctuating voltage measured by the correction device and the electromagnetic noise are A step of generating a list relating the values of correction data used to correct errors in ground voltage and measured by the measuring device based on pseudo electromagnetic noise;
In a state where the measuring device and the correction device are each installed at a place where electromagnetic noise is measured, acquiring the value of the correction data corresponding to the value of the fluctuating voltage measured by the correction device from the list, correcting the ground voltage of electromagnetic noise measured by the measuring device with the value of the correction data;
How to measure.

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