Electric field approach detection method

Abstract

To provide a method for detecting electric field proximity capable of capturing change in a magnitude of an electric field per unit time and an electroscope.SOLUTION: A method for detecting electric field proximity by an electroscope 1 is constituted as follows. The electroscope 1 detects magnitude of an ambient electric field for a plurality of times. When magnitude of the detected electric field is a predetermined value or more, warning is output. At the same time, based on the magnitude of the detected electric field, an amount of change in magnitude of the electric field per unit time is obtained. When the amount of change is larger than a predetermined value or more, warning is output.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric field approach detection method and a voltage detector that outputs a warning when a user such as a worker approaches an electric field of a live part, a power source, etc., in order to prevent electric shock accidents and the like to users such as workers. [Background technology]

[0002] Conventional voltage detectors detect the strength of the electric field of a live part, a power source, etc., and output a warning (alarm) if the strength of the detected electric field is equal to or greater than a threshold value.

[0003] For example, in Patent Document 1, the capacitance C between the AC voltage source V0 and the charging part and the human body is 01 and the capacitance C between the human body and the earth 02 The voltage V generated in the human body by 02 The document discloses a configuration that uses a voltage detector to measure the current flowing out of the human body due to the voltage. If the voltage detector is attached somewhere on the human body, a signal is output when the worker wearing the voltage detector approaches a voltage source. Therefore, even if a worker forgets to approach a live part during electrical work, a warning can be issued, preventing accidents such as electric shock. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-187067 Summary of the Invention [Problem to be solved by the invention]

[0005] However, even if a user such as a worker carries a conventional voltage detector to output a warning about approaching a 6.6 kV high-voltage charging section in a cubicle, if there is another electric field nearby, such as the voltage detector reacting to a nearby 6.6 kV power line, it is not possible to eliminate the possibility that the voltage detector will react to an electric field that is not the target (intended) electric field.

[0006] Furthermore, when a conventional electroscope is used in rainy weather or in a place where there are puddles at the feet, the sensitivity becomes unstable. This is because the presence of water causes the C 02 The dielectric constant of the capacitor increases, i.e., C 02 This is thought to be due to the increase in capacitance of the capacitor, resulting in a decrease in V (voltage). 02 If is small, the V detected by the electroscope C2 Therefore, conventional proximity sensors that output a warning when the detected voltage is above a threshold cannot accurately output a warning when a user such as a worker approaches the electric field of a live part or power source, depending on the weather and environment.

[0007] Incidentally, when considering the actions (motions) of workers and other users when they receive an electric shock, it is conceivable that a voltage detector would need to output a warning in two cases: 1) when they are very close to the electric field of a live part or power source, and 2) when they are approaching the electric field of a live part or power source.

[0008] However, even when approaching the electric field of a charging part, power source, etc. as described in 2) above, if a user such as a worker approaches the electric field slowly, the user is likely to be aware of the existence of the electric field. On the other hand, if a user such as a worker approaches the electric field suddenly, the user is likely to be unaware of the existence of the electric field and have forgotten about it.

[0009] In order to address the above-mentioned problems, the present invention aims to provide an electric field approach detection method and an electroscope that can detect changes in the magnitude of an electric field per unit time. [Means for solving the problem]

[0010] In order to achieve the above object, the invention according to claim 1 comprises: When viewed from the worker carrying or wearing the electroscope, there is another charging part that generates a noise electric field in front of the charging part that generates the electric field to be detected, or when the worker is located between the charging part that generates the electric field to be detected and the other charging part that generates the noise electric field, the electric field to be detected; The aforementioned Noise electric field and Heavy Becoming The situation that suits you, Alternatively, the electric field to be detected and the electric field that becomes the noise are in opposite phase at the position of the worker, The electric field to be detected The aforementioned Noise electric field and In a situation where these cancel each other out, The worker's Electric field to be detected The live part that forms Approaching The aforementioned voltage detector By In the method of detecting, The voltage detector teeth , The strength of the surrounding electric field is detected multiple times, Based on the detected magnitude of the electric field, the amount of change in the magnitude of the electric field per unit time is calculated, and if the amount of change is equal to or greater than a predetermined value, Assuming that the object of detection is approaching a charged part that forms an electric field, This is an electric field approach detection method that outputs a warning.

[0012] Also, claims 2 The invention relates to: The electroscope detects the voltage drop due to proximity to an electric field. The worker a first electrode for measuring the voltage induced in the human body, a second electrode for measuring the voltage relative to the ground, and a detection circuit; and Equipped with In the detection circuit, the first electrode and the second electrode with The current flowing due to the potential difference between the two electrodes is detected to detect the magnitude of the surrounding electric field. 1 The electric field approach detection method described in is used. [Effects of the Invention]

[0016] The present invention is configured to calculate the amount of change in the magnitude of the electric field per unit time, and if the amount of change is equal to or greater than a predetermined value, to output a warning. This makes it possible to identify actions by users such as workers that require a warning to be output (for example, quick movements that are not conscious of the presence of an electric field), and to output a warning appropriately for that action, which is convenient.

[0017] Furthermore, since the configuration identifies actions that require a warning to be output and outputs a warning appropriately for those actions, users such as workers do not receive unnecessary warnings, and the inconvenience caused when workers or other users carry the electric field approach detection voltage detector of the present invention is reduced, which is convenient. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic diagram illustrating the principle of a detection unit of an electroscope according to a first embodiment of the present invention. FIG. [Figure 2] 1 is a schematic vertical cross-sectional view showing an example of an electroscope according to a first embodiment of the present invention. [Figure 3] 1 is a perspective view showing an example of an electrode of a voltage detector according to a first embodiment of the present invention. FIG. [Figure 4] FIG. 3 is a schematic vertical cross-sectional view showing another example of the electroscope according to the first embodiment of the present invention. [Figure 5] FIG. 4 is a perspective view showing another example of an electrode of the electroscope according to the first embodiment of the present invention. [Figure 6] 1A and 1B are side views showing a state in which the voltage detector of the first embodiment of the present invention is attached to the helmet of a user such as a worker, in which FIG. 1A shows a clip fastening and FIG. 1B shows a band fastening. [Figure 7] 1A and 1B are side views showing the state in which the electroscope of the first embodiment of the present invention is attached to work shoes, in which FIG. 1A shows the electroscope fastened to the heel with a clip, and FIG. 1B shows the electroscope fastened to the toe with a band. [Figure 8] 1 is a configuration diagram of a detection circuit of a voltage detector according to a first embodiment of the present invention. FIG. [Figure 9] 1 is a schematic diagram illustrating the principle of a voltage detector relating to a voltage induced in a human body according to a first embodiment of the present invention. FIG. [Figure 10] This is a graph showing experimental results of the distance [cm] when a worker or other user's body approaches a live line and the electric field strength [V / m] of the charged human body. [Figure 11]This is a graph showing the simulation results of the distance [cm] when the human body of a user such as a worker approaches the target electric field and the electric field strength [V / m] of the charged human body as a curve. [Figure 12] This is a graph showing the simulation results of the distance [cm] when the human body of a user such as a worker approaches the target electric field and the electric field strength [V / m] of the charged human body as a curve. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention.

[0020] <Embodiment Example 1> FIG. 1 is a diagram showing the overall configuration of a voltage detector 1 according to the first embodiment.

[0021] <Configuration of Voltage Detector 1> As shown in Fig. 1, the voltage detector 1 is mainly composed of a first electrode 121, a second electrode 122, and a detection circuit 123. The voltage detector 1 is a proximity sensor having a first function of detecting the magnitude of the surrounding electric field, and if the detected magnitude of the electric field is equal to or greater than a predetermined value, outputting a warning such as a voice to a user such as a worker to warn the user that he or she is approaching the surrounding electric field. The voltage detector 1 is also a proximity sensor having a second function of calculating the amount of change in the electric field magnitude per unit time, and if the calculated amount of change is equal to or greater than a predetermined value, outputting a warning to warn the user such as a worker that he or she is approaching the surrounding electric field.

[0022] 2 and 3, the voltage detector 1 has a first electrode 121 made of a disk housed inside a box-shaped insulating case 124, a rod-shaped second electrode 122 provided vertically in the center of one surface of the first electrode 121, and a detection circuit 123 provided between the first electrode 121 and the second electrode 122. A clip 124a is also provided on the side surface of the insulating case 124.

[0023] 4 and 5, a first electrode 125 made of a disk is housed inside a box-shaped insulating case 124, a cylindrical second electrode 126 is provided vertically in the center of one surface of the first electrode 125, and a detection circuit 123 is provided between the first electrode 125 and the second electrode 126. Alternatively, a clip 124a may be provided on the side of the insulating case 124.

[0024] As shown in Fig. 6(a), the voltage detector 1 has an insulating case 124 attached to the rear of a work helmet 127 by clips 124a. Alternatively, as shown in Fig. 6(b), the voltage detector 1 may be attached to the work helmet 127 by bands 128 instead of clips 124a. Furthermore, as shown in Fig. 7(a), the insulating case 124 may be attached to the heel of a work shoe 129 by clips 124a. Alternatively, as shown in Fig. 7(b), the insulating case 124 may be attached to the instep of the toe of the work shoe 129 by bands 130.

[0025] 8, the detection circuit 123 is configured such that the C between the first electrode 121 or 125 and the second electrode 122 or 126 21 The voltage V generated by the current signal flowing through C2 and an amplifier circuit 131 for amplifying the amplified current voltage V C2 and the voltage V just before that (for example, 100 [msec] before) C2 The latest voltage V output from the memory circuit 132 is stored in the memory circuit 132. C2and the V one before that (for example, 100 [msec] before) C2 Only when a signal is output by a comparison circuit 133 that compares the signals, a sound generation circuit 134 and a lighting display circuit 135 are activated.

[0026] That is, the voltage detector 1 detects the magnitude of the surrounding electric field multiple times (twice, the most recent and the previous, in this embodiment 1) using the first electrode 121 or 125, the second electrode 122 or 126, the amplifier circuit 131, the memory circuit 132, and the comparison circuit 133, calculates the amount of change in the magnitude of the electric field per unit time (for example, 100 msec), and if the calculated amount of change is equal to or greater than a predetermined value, outputs a warning using the sound generation circuit 134 and the lighting display circuit 135 to alert users such as workers that they are approaching a surrounding electric field.

[0027] In addition, the detection circuits 123 are each provided with a reference voltage generating circuit 136, and a comparison circuit 137 compares the output signal of the amplifier circuit 131 with the output signal of the reference voltage generating circuit 136, and only when a signal is outputted, the sound generating circuit 134 and the lighting display circuit 135 are activated.

[0028] That is, the voltage detector 1 detects the magnitude of the surrounding electric field using the first electrode 121 or 125, the second electrode 122 or 126, the amplifier circuit 131, the reference voltage generating circuit 136, and the comparison circuit 137, and if the magnitude of the detected electric field is equal to or greater than a predetermined value, the sound generating circuit 134 and the lighting display circuit 135 output a warning such as a sound to the user, such as a worker, to warn the user that they are approaching a surrounding electric field.

[0029] The detection circuit 123 is also provided with a power supply 138, and power is supplied to the detection circuit 123 by turning on a switch 139 of the power supply 138.

[0030] Next, the principle of detecting the strength of the surrounding electric field by the electroscope 1 will be described.

[0031] The applicant of this application has discovered that when a human body approaches an electric field such as a live part or power source, current flows from the electric field into the human body through the arms, torso, and head, and this current causes the human body to have an AC potential from the ground, and the human body potential causes current to flow through the arms, legs, and head on the opposite side of the electric field via the capacitance between the human body and the ground.

[0032] Based on this knowledge (principle), the applicant of the present application has created the configuration of the voltage detector 1. As shown in FIG. 9, the combined capacitance (C 01 and C 02 The series connection of C0 is expressed as the following equations 1 and 2. V0 is the potential of the voltage source W to the ground G, and V 01 is the capacitance C between the voltage source W and the human body H 01 potential due to V 02 is the capacitance C of the human body H to the ground G 02 The potential due to

[0033]

number

[0034]

number

[0035] Therefore, equations 3 and 4 are obtained, and the human body H has a potential (V 02 )

[0036]

number

[0037]

number

[0038] Also, from equations 5 and 6, the closer the human body H is to the electric field W, the 01 d becomes smaller, and C01 becomes larger)V 02 This increases V 02 If we can detect the magnitude of the surrounding electric field W, we can detect the magnitude of the surrounding electric field W. Also, because of equations 5 and 6, the closer the human body H is to the charging part, the greater the magnitude of the electric field W (C 01 d becomes smaller, and C 01 becomes larger)V 02 This increases V 02 If this can be detected, it is possible to detect "a person (human body H) approaching a live part."

[0039]

number

[0040]

number

[0041] Next, this is applied to the electroscope 1. As described above, the electroscope 1 is composed of the first electrode 121 or 125, the second electrode 122 or 126, and the detection circuit 123 (see FIG. 1). Here, C1 is the capacitance between the human body H and the first electrode 121 or 125, C 21 is the capacitance between the first electrode 121 or 125 and the second electrode 122 or 126, C 22 is the capacitance between the human body H and the second electrode 122 or 126, and C 31 is the capacitance between the first electrode 121 or 125 and the ground G, C 32 is the capacitance between the second electrode 122 or 126 and the ground G.

[0042] The overall combined capacitance of this electroscope 1 is expected to be the following equation (7): C2 This V C2 is the voltage that indicates the strength of the surrounding electric field.

[0043]

number

[0044]

number

[0045] In this way, the first electrode 121 or 125 is attached to the human body H of a user such as a worker via the dielectric work helmet 127 or work shoes 129 and insulating case 124, and when the human body H approaches the surrounding electric field W, a minute current flows into the human body H of the user such as a worker. A current is then generated between the first electrode 121 or 125 and the second electrode 122 or 126, which is detected by the detection circuit 123 to detect the magnitude of the surrounding electric field W.

[0046] <Study on the effectiveness of voltage detector 1> Next, the results of the investigation into the effectiveness of the voltage detector 1 will be shown.

[0047] As a field test of the voltage detector 1, a test was conducted in which a user such as a worker wearing the voltage detector 1 on a work helmet 127 approached a 6.6 kV high-voltage charging part of a cubicle, and the voltage detector 1 reacted to a nearby 6.6 kV power line.

[0048] If we consider a transmission line as a cylindrical charge distribution of infinite length, the electric field created by the transmission line is E=q / 2πεr.

[0049] Figure 10 shows the experimental results of the distance [cm] when a worker or other user approaches a 3 [kV] live line, and the electric field strength [V / m] of the charged human body. Referring to this experimental result, it can be seen that the electric field formed by the cubicle is close to E=q / 2Πεr (inversely proportional to the distance r). The formula for the approximate curve showing the electric field strength of the charged human body in Figure 10 is E=201r^(-1.1)=201 / r 1.1 This becomes:

[0050] Regarding the surrounding electric field detected by voltage detector 1 approaching the cubicle, we will consider from the equation of the approximate curve above which has a stronger influence: the electric field formed by the power line or the electric field formed by the cubicle. Regarding the distance r from voltage detector 1 to the cubicle, "distance from power line to voltage detector 1 > distance from cubicle to voltage detector 1", so the influence of the electric field formed by the cubicle is stronger. Regarding the amount of charge (current value), "current value flowing in the power line > current value flowing in the cubicle", so the influence of the electric field formed by the power line is stronger. Depending on the situation, it cannot be ruled out that voltage detector 1 may react due to the presence of a power line.

[0051] Based on the above study results, we consider that the formula for the electric field strength [V / m] of a charged human body is approximated by E = 201 / r, and further study the influence of the noise electric field on the detection of the electric field around the electroscope 1 depending on the arrangement of the target electric field (cubicle) and the noise electric field (power line).

[0052] When the positional relationship between the power line, the cubicle, and the user (e.g., worker) is "cubicle-user-power line," the electric field generated by the power line affects the detection of the user's approach to the cubicle. Specifically, as the user (e.g., worker) approaches the cubicle, the influence of the electric field generated by the cubicle becomes stronger, while the influence of the electric field generated by the power line becomes weaker. However, since the influence of the electric field generated by the power line is inversely proportional to the distance, and the distance between the power line and the user (e.g., worker) is sufficiently greater than the distance between the cubicle and the user (e.g., worker), the change in the magnitude of the electric field generated by the power line is likely to be small near the cubicle (especially within 100 cm). Therefore, capturing the change in the magnitude of the electric field per unit time as the distance between the user (e.g., worker) and the cubicle decreases is considered to be almost similar (synonymous) to capturing the change in the magnitude of the electric field generated by the cubicle near the cubicle.

[0053] Figure 11 is a curve graph showing a simulation to verify whether the above study results are correct, assuming a power line 10 m away from the cubicle in the above arrangement. It can be seen that when a worker or other user approaches less than 100 cm from the cubicle (the area enclosed by a square in Figure 11), they are not affected by the electric field generated by the power line.

[0054] When the positional relationship between the power line, the cubicle, and the user (e.g., worker) is "power line, cubicle, user (e.g., worker")," the electric field generated by the power line affects the detection of the user's approach to the cubicle. Specifically, as the user (e.g., worker) approaches the cubicle, the influence of the electric field generated by the cubicle becomes stronger, but the influence of the electric field generated by the power line also becomes stronger, making it difficult to determine which electric field the user is approaching. However, because the distance between the power line and the user (e.g., worker) is significantly greater than the distance between the cubicle and the user (e.g., worker), the change in the magnitude of the electric field generated by the power line is likely to be small near the cubicle (especially within 100 cm). Therefore, capturing the change in the magnitude of the electric field per unit time as the distance between the user (e.g., worker) and the cubicle decreases is considered to be nearly identical (synonymous) to capturing the change in the magnitude of the electric field generated by the cubicle near the cubicle.

[0055] Figure 12 is a curve graph showing a simulation to verify whether the above study results are correct, assuming a power line 10 m away from the cubicle in the above arrangement. It can be seen that when a worker or other user approaches less than 100 cm from the cubicle (the area enclosed by a square in Figure 12), they are not affected by the electric field of the power line.

[0056] By being configured to capture the amount of change in the magnitude of the electric field per unit time, like this electroscope 1, danger can be accurately detected even in situations where the electric field to be detected and the electric field that becomes noise overlap (for example, there is a noise electric field in front or behind) or where the electric field to be detected and the electric field that becomes noise cancel each other out (for example, when the electric field to be detected and the electric field that becomes noise are in opposite phase).On the other hand, conventional electroscopes are configured to detect the strength of the electric field of a live part, power source, etc., and output a warning (alarm) if the strength of the detected electric field is above a threshold, so it is not possible to determine whether the cause of the warning is the influence of the electric field to be detected or the influence of the electric field that becomes noise, and therefore danger cannot be accurately detected.

[0057] <Voltage detector 1 warning output pattern> As described above, the voltage detector 1 of the first embodiment has a first function of detecting the magnitude of the surrounding electric field and outputting a warning to a user such as a worker when the detected magnitude of the surrounding electric field is equal to or greater than a predetermined value. The voltage detector 1 also has a second function of calculating the amount of change in the electric field magnitude per unit time and outputting a warning when the calculated amount of change is equal to or greater than a predetermined value.

[0058] Regarding the settings for how to output the warning based on the first function and the warning based on the second function, various patterns can be considered depending on the stage of proximity to the target electric field, the behavior of the user such as a worker, etc. Furthermore, the warning based on the first function and the warning based on the second function may be configured to have different warning methods or patterns.

[0059] For example, to warn users such as workers approaching on foot electric fields located indoors, above ground, or underground, such as in cubicles or high-voltage charging stations, a predetermined value (= absolute value of electric field magnitude: 220 [V / m]) is set so that a warning related to the first function (e.g., a continuous alarm sound or a lit alarm) is output to indicate the final deadline for prohibiting approach to the target electric field (e.g., 1 [m] from the target electric field). Furthermore, to encourage users such as workers approaching the target electric field to be careful with their actions (movements), a predetermined value (= change in electric field magnitude: 164 [V / m]) is set so that a warning related to the second function (e.g., an intermittent alarm sound or a flashing alarm) is output even if they are a little farther away (e.g., 120 [m] from the target electric field).

[0060] Furthermore, for example, to alert users such as workers when they approach an electric field located at a high place, such as a cable head on a utility pole, a transformer terminal, or an overhead distribution line, using a bucket (≒basket) of an aerial work vehicle, a predetermined value (= absolute value of the electric field magnitude: 167 [V / m]) is set so that a warning related to the first function (e.g., an intermittent alarm or a flashing alarm) is output to indicate approach to the target electric field (e.g., 2.6 [m] from the target electric field). Furthermore, to encourage users such as workers who come very close (e.g., 1 [m]) to the target electric field to be more careful in their actions, a predetermined value (= change in the electric field magnitude: 119 [V / m]) is set so that a warning related to the second function (e.g., a continuous alarm or a lit alarm) is output.

[0061] In this way, by changing the settings for the warning based on the first function and the warning based on the second function, the voltage detector 1 can appropriately warn users such as workers according to various situations, such as the location of the target electric field and how the user such as a worker approaches (for example, whether they approach on foot or by vehicle).

[0062] <Modification> In the first embodiment, the voltage detector 1 has the first function and the second function, but the present invention is not limited to this configuration. For example, the voltage detector 1 may have only the second function, which calculates the amount of change in the magnitude of the electric field per unit time and outputs a warning when the calculated amount of change is equal to or greater than a predetermined value.

[0063] In addition, in the first embodiment, the voltage induced in the human body is measured by the electroscope 1, that is, the human body is used to measure the magnitude of the surrounding electric field, but the present invention is not limited to this configuration. Any configuration is acceptable as long as the electroscope 1 can measure the magnitude of the surrounding electric field.

[0064] Furthermore, in the first embodiment, the voltage detector 1 is configured to output a warning by a combination of sound and light, but the present invention is not limited to this configuration. For example, the voltage detector 1 may be configured to output a warning only by sound, or may be configured to output a warning only by light.

[0065] Furthermore, in the voltage detector 1 according to the first embodiment, a configuration is shown in which a warning is output when the magnitude of the detected surrounding electric field or the calculated change in the surrounding electric field is "equal to" a predetermined value set in advance, but the present invention is not limited to this configuration. For example, a configuration may be adopted in which a warning is output when "exceeds" a predetermined value set in advance.

[0066] Furthermore, in the first embodiment, as an example of calculating the amount of change in the magnitude of the electric field per unit time based on the magnitude of the electric field detected by the detection circuit 123 of the electroscope 1, a configuration has been shown in which the latest detection result stored in the memory circuit 132 is compared with the previous detection result one detection result before that (for example, 100 [msec] before) to determine the amount of change (= the amount of change from the previous detection result to the latest detection result), but the present invention is not limited to this configuration. For example, the detection circuit 123 may be configured to compare the latest detection result stored in the memory circuit 132 with the detection result two detection results before that (for example, 200 [msec] before) to determine the amount of change (= the amount of change from the detection result two detection results before that), and in short, any configuration that can determine the amount of change in the magnitude of the electric field over time will suffice.

[0067] In the first embodiment, the detection circuit 123 is configured by combining elements such as the comparison circuit 133, the reference voltage generation circuit 136, and the comparison circuit 137, but the configuration is not limited to this. For example, the detection circuit 123 may have a control unit (not shown) realized by a microcomputer made up of a single LSI, and the control unit may be configured to detect the latest voltage V detected by the first electrode 121 and the second electrode 122. C2 and the voltage V just before that (for example, 100 [msec] before) C2 The difference (amount of change) is calculated based on the above, and if the calculated difference is equal to or greater than a predetermined value set in advance, the sound generating circuit 134 or the like may be configured to output a warning. [Explanation of symbols]

[0068] 1: voltage detector, 121: first electrode, 122: second electrode, 123: detection circuit, 124: insulating case, 124a: clip, 125: first electrode, 126: second electrode, 127: work helmet, 128: band, 129: work shoes, 130: band, 131: amplifier circuit, 132: memory circuit, 133: comparison circuit, 134: sound generation circuit, 135: lighting display circuit, 136: reference voltage generation circuit, 137: comparison circuit, 138: power supply, 139: switch

Claims

1. A method for detecting the approach of a worker using a voltage detector to a live part that forms an electric field to be detected in a situation where, as viewed from the worker carrying or wearing the voltage detector, there is another live part that forms an electric field that becomes noise in front of the live part that forms the electric field to be detected, or the worker is positioned between the live part that forms the electric field to be detected and the other live part that forms the electric field that becomes noise, causing the electric field to be detected and the electric field that becomes noise to overlap, or where the electric field to be detected and the electric field that becomes noise are in opposite phase at the worker's position, causing the electric field to be detected and the electric field that becomes noise to cancel each other out, The electroscope is The strength of the surrounding electric field is detected multiple times, An electric field approach detection method characterized by calculating the amount of change in the electric field strength per unit time based on the strength of the detected electric field, and if the amount of change is greater than or equal to a predetermined value, outputting a warning that the person is approaching a charged part that generates the electric field to be detected.

2. the electroscope comprises a first electrode for measuring a voltage induced in the worker's body by proximity to an electric field, a second electrode for measuring a voltage relative to ground, and a detection circuit; 2. The electric field approach detection method according to claim 1, wherein the detection circuit detects the magnitude of the surrounding electric field by capturing a current that flows due to a potential difference between the first electrode and the second electrode.

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