A Detection Device and Method for Indirectly Locating the Direction of Energized Conductors

Abstract

An indirect positioning detection device for the direction of a live wire, comprising a mounting frame, a mounting platform, a motor, a synchronous belt, a plurality of rectangular PCB Rogowski coils, Rogowski coil mounting seats, a display screen, a signal acquisition module, and a signal processing module; the motor provides power and transmits power to the plurality of rectangular PCB Rogowski coils through power transmission, enabling the plurality of rectangular PCB Rogowski coils to move as required under command control; the plurality of planar rectangular PCB Rogowski coils are configured in an equiangular or extended line angle of the plane where they are located. By measuring the induced voltage of the magnetic induction lines in two or more dimensional directions and performing amplification, integration, and ratio analysis on the induced voltage amounts from the magnetic field to each induction plane, the wire routing direction of the non-directly contactable wire or the direction of the locally dynamically changing magnetic field can be determined from a geometric perspective. This method has a relatively low cost and high practical application value.

Description

Technical Field

[0001] This invention patent relates to the application of the vector field strength of the electric field of a wire, and particularly to a method for indirectly positioning the direction of a wire. Background Art

[0002] In actual industrial application scenarios, the magnitude and direction of the current transmitted in a wire can be obtained non-contact by acquiring the magnetic field strength at a fixed distance around the current transmission line, and the direction of a shallowly buried wire can also be positioned in a non-visible form.

[0003] Current methods and deficiencies of wire positioning: 1. The existing wire direction positioning methods mainly rely on the induction of the electric field strength in one-dimensional direction or the capture of the magnetic field induction intensity in one-dimensional direction by a Rogowski coil to repeatedly adjust the position to obtain the possible position direction. The existing methods rely more on manual operation and require multi-angle and multiple tests to obtain the approximate position direction. Such methods are time-consuming, rely more on the judgment of manual experience, and cannot accurately determine the wire direction through the method of multi-dimensional vector induction ratio. 2. The current Rogowski coil structures are mostly annular, and the effective induction area is relatively irregular, which is not conducive to calculating the induction intensity during the wire direction positioning process. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for indirectly positioning the direction of a live wire in view of the above problems.

[0005] A detection device for indirectly positioning the direction of a live wire includes an installation frame, an installation platform, a motor, a synchronous belt, a plurality of rectangular PCB Rogowski coils, a Rogowski coil mounting seat, a display screen, a signal acquisition module, and a signal processing module; the motor provides power and provides power for the plurality of rectangular PCB Rogowski coils through power transmission, so that the plurality of rectangular PCB Rogowski coils can move as required under command control; the plurality of planar rectangular PCB Rogowski coils are composed of two parts, namely a group A coil and a group B coil. The coils in group A rotate horizontally around the center point of any rectangle in space and are evenly distributed at equal angles, and the coils in group B rotate three-dimensionally around one side of the rectangle and are evenly distributed at equal angles.

[0006] Each rectangular PCB Rogowski coil includes two unidirectional unclosed coils. Connecting the ends of these two single-ended unclosed coils together forms a rectangular PCB Rogowski coil.

[0007] The rectangular PCB Rogowski coil is formed into a rectangular contour using a rigid PCB type, and the coil winding method has uniformly spaced parallel traces inside.

[0008] The number of the group A coil and the group B coil are both one, which are a horizontal rectangular PCB Rogowski coil and a vertical rectangular PCB Rogowski coil respectively.

[0009] The rectangular PCB Rogowski coil adopts a parallel double-wire winding mode.

[0010] There is a copper-clad interlayer between the windings on the front and back sides of the PCB of the Rogowski coil.

[0011] The interlayer is embedded between the front Rogowski coil wiring and the back Rogowski coil wiring; the interlayer can be a copper sheet or other metal sheet that has the function of shielding electric fields but not magnetic fields.

[0012] The signal acquisition module enables a plurality of rectangular PCB Rogowski coils to sense and acquire signals with different amplitudes, and then transmit the signals to the signal processing module through twisted pair cables.

[0013] The function of the signal processing module is to input the collected DC and AC signals into the analog signal sampling terminal of the MCU after the output signal of the rectangular PCB Rogowski coil passes through an operational amplifier, an active filter, and a low-pass filter.

[0014] A method for indirectly locating the direction of a live wire includes a detection device for indirectly locating the direction of a live wire; the method includes the following steps:

[0015] Step 1: Power on the load circuit to be tested;

[0016] Step 2: Place the detection device near the area where the wire may exist, and first obtain an X-direction sampling value with a certain amplitude;

[0017] Step 3: According to the "arrow" direction prompt displayed on the detection device, the operator moves the detection device in the direction where the maximum value of the X-axis sensing value exists; stop moving when the X-axis value no longer changes.

[0018] Step 4: The internal motor rotates automatically, rotating the measuring coil assembly device 90°, and adjusting the position of the rectangular coil assembly;

[0019] Step 5: At the same position, translate the measuring device left and right along the Z-axis direction; when the induction of the Z-axis coil reaches the maximum value and the induction of the X-axis coil reaches the minimum value during the movement, it means that the direction of the adjacent coil is parallel to the X-axis and perpendicular to the Z-axis; at this time, the wire is located directly below the X-rectangular coil.

[0020] The Rogowski coil is an electrical device used to measure alternating current (AC) or high-speed current pulses. The Rogowski coil is a spiral hollow toroidal coil, and the inside is made of a material with a magnetic permeability approximately equal to that of vacuum permeability. It can be directly sleeved on the conductor to be measured. The alternating current flowing through the conductor will generate an alternating magnetic field around the conductor, thereby inducing an alternating voltage signal proportional to the current ratio in the coil.

[0021] The principle of the Rogowski coil is schematically shown in the appendix Figure 7 as shown, where "i(t)" is the vertical wire passing through the Rogowski coil. The equivalent model for measurement is shown in the appendix Figure 8 as shown.

[0022] If the resistance at the load end is R S (the load end is generally the input end of the signal amplification or processing section), from Figure 8 the equivalent model, we can get:

[0023]

[0024]

[0025] Combining equation (1) and equation (2), we get

[0026]

[0027] In equation (3), C is the distributed capacitance of the Rogowski coil, R is the resistance of the Rogowski coil, L is the self-inductance of the coil, and M is the mutual inductance of the coil. Usually, C is very small and can be ignored. Therefore, the output of the Rogowski coil is simplified to

[0028]

[0029] When , that is, when ωL C >> (R c + R S )i2(t), we get

[0030]

[0031] And further, the relationship between the output voltage and the current is obtained as

[0032]

[0033] The output is proportional to the input. The Rogowski coil operates in the self-integration mode. When , we get

[0034]

[0035] At this time, the integral of the input current is equal to the output voltage, and the Rogowski coil operates in the external integration mode. After processing the amplification and integration circuit at the output end of the Rogowski coil, the induced voltage value can be obtained.

[0036] For the rigid rectangular variant Rogowski coil as shown in the appendix Figure 1 When the plane of the Rogowski coil and the wire routing direction at the center point of the rectangle are both perpendicular to the external wire at the same time, the induced amount obtained by the Rogowski coil is the largest. The coil plane and the wire at the center of the coil at this time are respectively set as the "original plane" and the "original center line". Figure 2 is the front of the Rogowski coil in the form of a rectangular printed circuit board, Figure 3 is the back of the Rogowski coil in the form of a rectangular printed circuit board, Figure 4 is a schematic diagram of the relative positions of the A coil and the B coil of the Rogowski coil in the form of a rectangular printed circuit board installed inside the measuring device.

[0037] When the plane of the Rogowski coil is perpendicular to the wire direction, the induced amount obtained by the Rogowski coil is the largest. When the plane direction of the coil or the winding direction is not perpendicular to the wire, the effective induced amount is proportional to the effective area of the current position projected on the original plane, and is proportional to the projected length of the wire routing direction (all wire bodies inside the coil are parallel lines) to the original center line.

[0038] Taking a single-turn Rogowski coil as an example, the induced voltage brought by the magnetic flux is

[0039]

[0040] B where S is an arbitrary surface with a closed loop as the edge, da is the vector of the infinitesimal surface element, and Φ

[0041] is the magnetic flux passing through the surface S. It can be seen that under the same magnetic flux, the larger the closed area passed through, the higher the induced voltage. When the middle position of the plane of the rectangular printed circuit board Rogowski coil is perpendicular to the wire, the induced amount is the largest. At this time, the included angle θ between the normal line of the original coil plane and the wire is 0 degrees. When the wire is not parallel to the normal line, the relationship between the induced voltage and the magnetic flux is

[0042]

[0043] When the current in the wire reaches a certain value, the magnetic field intensities at the positions of the two small-sized rectangular Rogowski coils are basically the same, and the ratio of the obtained induced voltage values is approximately equal to the ratio of the included angle cosθ, and is also equal to the ratio of θ. Therefore, by reading the ratio of the induced voltage values of the two Rogowski coils that are perpendicular to each other, the ratio of the included angle between the wire and the normal line of the plane where the Rogowski coil is located can be approximately obtained.

[0044] Since the PCB Rogowski coil is designed with a certain thickness structure, the coils on each plane can detect the magnetic field passing through the effective closed space of the Rogowski coil parallel to this plane. By measuring the induced voltage of the magnetic induction lines in two or more dimensional directions, and performing amplification, integration, and ratio analysis on the induced voltage amounts from the magnetic field to each induction plane, the wire routing direction that cannot be directly contacted or the direction of the locally dynamically changing magnetic field can be determined from a geometric perspective. This method has a relatively low cost and high practical application value.

[0045] The detection device and positioning method of this solution can simply and effectively obtain the position and routing of the wire to be measured through the automatic rotation of the rectangular coil. The positioning speed is fast, the anti-interference effect is good, and the cost performance is high. It can be used in engineering construction sites such as wire positioning and routing tracking in closed walls or floors. At the same time, multiple rectangular coils are set in two groups, namely Group A and Group B, and a spatial structure distribution pattern is designed, making the spatial coverage higher and the detection efficiency better. Description of the Drawings

[0046] Figure 1 Schematic diagram of the positional relationship between the Rogowski coil in the form of a rectangular printed board with a sandwich layer and the wire;

[0047] Figure 2 Front side routing of the Rogowski coil in the form of a rectangular printed board;

[0048] Figure 3 Back side routing of the Rogowski coil in the form of a rectangular printed board;

[0049] Figure 4 Relative position of the rectangular Rogowski coil inside the measuring device;

[0050] Figure 5 Schematic diagram of the error interference area of a single-turn coil;

[0051] Figure 6 Side view of the rectangular Rogowski coil (the dashed line is the inner layer copper foil);

[0052] Figure 7 Schematic diagram of the circular Rogowski coil measuring current;

[0053] Figure 8 Equivalent circuit model when the Rogowski coil measures the magnetic induction quantity;

[0054] Figure 9 Three-view drawings of the detection device used in the detection method of the present invention.

[0055] The markings in the attached drawings are as follows: 1. mounting frame; 2. mounting platform; 3. servo motor; 4. synchronous belt; 5. horizontal rectangular PCB Rogowski coil; 6. vertical rectangular PCB Rogowski coil; 7. Rogowski coil mounting seat; 8. shielding cover; 10. signal acquisition module; 11. signal processing module. Detailed implementation mode

[0056] The Rogowski coil is an electrical device used to measure alternating current (AC) or high-speed current pulses. The Rogowski coil is a spiral hollow toroidal coil, and the inside is made of a material with a magnetic permeability approximately equal to that of vacuum permeability, and it can be directly sleeved on the conductor to be measured. The alternating current flowing through the conductor will generate an alternating magnetic field around the conductor, thereby inducing an alternating voltage signal proportional to the current ratio in the coil.

[0057] The principle of the Rogowski coil is schematically shown in the attached Figure 7 drawing, where "i(t)" is the vertical wire passing through the Rogowski coil. The equivalent model for measurement is shown in the attached Figure 8 drawing.

[0058] If the resistance at the load end is R S (the load end is generally the input end of the signal amplification or processing section), from Figure 8 the equivalent model, we can obtain:

[0059]

[0060]

[0061] Combining Equation (1) and Equation (2), we get

[0062]

[0063] In Equation (3), C is the distributed capacitance of the Rogowski coil, R is the resistance of the Rogowski coil, L is the self-inductance of the coil, and M is the mutual inductance of the coil. Usually, C is very small and can be ignored. Therefore, the output of the Rogowski coil is simplified to

[0064]

[0065] When ωL C >> (R c + R S ) i2(t), we get

[0066]

[0067] and further obtain the relationship between the output voltage and the current as

[0068]

[0069] The output is proportional to the input. The Rogowski coil operates in the self-integration mode. When it is obtained

[0070]

[0071] At this time, the integral of the input current is equal to the output voltage, and the Rogowski coil operates in the external integration mode. After processing the amplification and integration circuit at the output end of the Rogowski coil, the induced voltage value can be obtained.

[0072] For a Rogowski coil in the form of a sandwich rectangular printed circuit board as shown in the appendix Figure 1 When the plane of the Rogowski coil and the wire direction of the center point of the rectangle in the coil plane are both perpendicular to the external wire at the same time, the induced quantity obtained by the Rogowski coil is the largest. The coil plane and the wire at the center of the coil at this time are respectively set as the "original plane" and the "original center line". Figure 2 is the front of the Rogowski coil in the form of a rectangular printed circuit board, Figure 3 is the back of the Rogowski coil in the form of a rectangular printed circuit board, Figure 4 is a schematic diagram of the relative positions of the A coil and the B coil of the Rogowski coil in the form of a rectangular printed circuit board installed in the measuring device.

[0073] When the plane of the Rogowski coil is perpendicular to the wire direction, the induced quantity obtained by the Rogowski coil is the largest. When the plane direction of the coil or the winding direction is not perpendicular to the wire, the effective induced quantity is proportional to the effective area of the current position projected on the original plane, and is proportional to the projected length of the wire direction of the coil (all the main wires in the coil are parallel lines) to the original center line.

[0074] Taking a single-turn Rogowski coil as an example, the induced voltage brought by the magnetic flux is

[0075]

[0076] where S is an arbitrary surface with a closed loop as the edge, da is the vector of the infinitesimal surface element, and Φ B is the magnetic flux passing through the surface S. It can be seen that under the same magnetic flux, the larger the closed area passed through, the higher the induced voltage.

[0077] When the middle position of the plane of the rectangular printed circuit board Rogowski coil is perpendicular to the wire, the induced quantity is the largest. At this time, the included angle θ between the normal line of the original plane of the coil and the wire is 0 degree. When the wire is not parallel to the normal line, the relationship between the induced voltage and the magnetic flux is

[0078]

[0079] When the current in the wire reaches a certain value, the magnetic field intensities at the positions of the two small-sized rectangular Rogowski coils are basically the same, and the ratio of the obtained induced voltage values is approximately equal to the ratio of the included angle cosθ, and is also equal to the ratio of θ. Therefore, by reading the ratio of the induced voltage values of the two mutually perpendicular Rogowski coils, the ratio of the included angle between the wire and the normal of the plane where the Rogowski coil is located can be approximately obtained. Therefore, the wiring direction of the rectangular coil in the Z-axis is the Y-axis direction.

[0080] A detection device for indirectly positioning the direction of a live wire includes a mounting frame, a mounting platform, a motor, a synchronous belt, a plurality of rectangular PCB Rogowski coils, a Rogowski coil mounting seat, a display screen, a signal acquisition module, and a signal processing module; the motor provides power and transmits power through a power transmission mechanism to provide power for the plurality of rectangular PCB Rogowski coils, so that the plurality of rectangular PCB Rogowski coils can move as required under command control; the plurality of planar rectangular PCB Rogowski coils are composed of two parts, namely a group A coil and a group B coil. The plurality of coils in group A rotate horizontally around the center point of any rectangle in space and are evenly distributed at equal angles, and the coils in group B rotate three-dimensionally around one side of the rectangle and are evenly distributed at equal angles.

[0081] When there are three rectangular PCB Rogowski coils, they are orthogonal and perpendicular to each other. When there are more than three PCB Rogowski coils, the plurality of planar rectangular PCB Rogowski coils are composed of two parts, namely a group A and a group B. The plurality of coils in group A rotate horizontally around the center point of a rectangle in space and are evenly distributed at equal angles, and the coils in group B rotate three-dimensionally around one side of the rectangle and are evenly distributed at equal angles. The cross-section of group B is similar to a spatial combination in the shape of a "rice" character.

[0082] Furthermore, a signal acquisition combination is formed by using at least two groups of planar rectangular PCB Rogowski coils in an equal-angle or extended-line-of-plane-angle configuration.

[0083] Specifically, the detection device used in the method for indirectly positioning the direction of a live wire according to the present invention includes a mounting frame 1, a mounting platform 2, a servo motor 3, a synchronous belt 4, a first rectangular PCB Rogowski coil 5, a second rectangular PCB Rogowski coil 6, a Rogowski coil mounting seat 7, a shielding cover 8, a display screen, a signal acquisition module 10, and a signal processing module 11; the servo motor 3 provides power and drives the synchronous belt 4 to move, thereby providing power for the horizontal rectangular PCB Rogowski coil 5 and the vertical rectangular PCB Rogowski coil 6, so that the two can move as required under command control.

[0084] Furthermore, a rectangular contour is formed by using a rigid PCB type, and the coil winding method has parallel wiring inside with uniform equal spacing.

[0085] The Rogowski coil in the form of a single-piece rectangular PCB meets the lateral anti-interference design. The "parallel double-wire winding" mode adopted by the single-piece rigid Rogowski coil is in the form that the front and back sides coincide with each other's projections on the main wire, and are connected together at the tail end. Attach the Figure 1 After the decomposed coil, its individual A coil (unidirectional) and B coil (unidirectional) are as attached Figure 2 and Figure 3 shown. Looking at the coil from the left side, the A coil is wound counterclockwise and the B coil is wound clockwise. The plane projection area of the closed area formed by the lead terminals "A" and "B" is reduced to the lowest level acceptable by the PCB process, so that the interference induction caused by the presence of wires parallel to the plane where the Rogowski coil is located can be negligible. A and B are two single-wire unidirectional coils. They start from the two solder pads "A" and "B" respectively, one is wound clockwise and the other is wound counterclockwise, and are connected together at the end of the rectangle to jointly form a closed coil. The horizontal rectangular PCB Rogowski coil 5 and the vertical rectangular PCB Rogowski coil 6 are both closed coils.

[0086] There is a copper-clad sandwich layer in the middle of the front and back sides of the PCB of the Rogowski coil. The sandwich layer is embedded between the front-side Rogowski coil wire and the back-side Rogowski coil wire. The sandwich layer can be a copper-clad sheet or other metal material thin sheets with the function of shielding the electric field but not the magnetic field. Because the magnetic permeability of this metal material is greater than that of the original non-metal PCB dielectric layer, it is beneficial to increase the effective induction of the coil and reduce the interference of relative noise.

[0087] The function of the signal acquisition module 10 is that the designed two mutually perpendicular rectangular PCB Rogowski coils collect signals with different amplitudes and send them to the signal processing module through twisted pairs.

[0088] The function of the signal processing module 11 is to input the output signals of the rectangular PCB Rogowski coil into the analog signal sampling terminal of the MCU after passing through an operational amplifier, an active filter, and a low-pass filter for the collected DC and AC signals. So as to facilitate the operation and processing of the signals.

[0089] Working principle of the detection device: Start the device at a certain point on the plane to be measured. When the servo motor controls the rotation of two mutually perpendicular Rogowski coils, the rectangular PCB Rogowski coil 5 parallel to the plane to be measured must be parallel to the live wire to be measured at a certain angle during the rotation of the motor, and the obtained value is the minimum sampling value among the 360° angles. At this time, the value obtained by the other vertical rectangular PCB Rogowski coil 6 perpendicular to the horizontal rectangular PCB Rogowski coil 5 in the acquisition module is the maximum induction value among the 360° angles, and the device display screen will prompt the operator to continue to swing back and forth a certain distance along the long side direction of the rectangle of the vertical rectangular PCB Rogowski coil 6. When swinging in one of the two directions, when the sampling value of the horizontal rectangular PCB Rogowski coil 5 basically does not change and the sampling value of the vertical rectangular PCB Rogowski coil 6 increases, the screen will display an arrow to continue moving along the direction that increases the sampling value of the vertical rectangular PCB Rogowski coil 6; when moving to the point where the value of the vertical rectangular PCB Rogowski coil 6 no longer increases, the horizontal rectangular PCB Rogowski coil 5 is located directly above the live wire and parallel to the live wire. At this time, the device gives a prompt "Detection completed" and displays the wire routing direction on the screen.

[0090] An indirect method for positioning the direction of a live wire according to the present invention includes the following steps:

[0091] Including a detection device;

[0092] Step 1: Power on and turn on the load circuit to be detected;

[0093] Step 2: Place the detection device near the area where the wire may exist and first obtain the sampling value in the X direction with a certain amplitude;

[0094] Step 3: According to the "arrow" direction prompt displayed on the detection device, the operator holds the detection device and moves in the direction where the maximum value of the induction in the X-axis direction exists; stop moving when the value in the X-axis direction no longer changes.

[0095] Step 4: The internal motor rotates automatically to rotate the measurement coil combination device by 90° to adjust the position of the rectangular coil combination;

[0096] Step 5: Translate the measurement device left and right along the Z-axis direction at the same position; when, during the movement, the induction of the Z-axis coil obtains the maximum value and the induction of the X-axis coil obtains the minimum value, it indicates that the direction of the adjacent coil is parallel to the X-axis and perpendicular to the Z-axis; at this time, the wire is located directly below the X rectangular coil.

[0097] Regarding the error, Figure 6 The single-turn error induction area relative to the effective induction area, that is, the area formed by the thickness H and width W of the PCB hard coil (approximately equal to the cross-sectional area of the rectangular coil), is generally designed to be greater than 50 mm2 , Figure 5 For the interference error caused by the shadow area, it is less than 0.5 mm in actual design. 2 The induction area is generally more than 100 times larger than the lateral error area and can be ignored.

[0098] The positioning method and detection device of this solution can simply and effectively obtain the position and orientation of the wire under test by automatically rotating the rectangular coil. The positioning speed is fast, the anti-interference effect is good, and the cost performance is high. It can be used for wire positioning and orientation tracking in engineering construction sites such as enclosed walls or underground floors.

[0099] The above-described embodiments merely represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An inspection device for indirectly positioning the direction of a live wire, characterized in that: It includes an installation rack, an installation platform, a motor, a synchronous belt, multiple rectangular PCB Rogowski coils, Rogowski coil mounting seats, a display screen, a signal acquisition module, and a signal processing module; the motor provides power and transmits power to the multiple rectangular PCB Rogowski coils through power transmission, enabling the multiple rectangular PCB Rogowski coils to move as required under command control; the multiple rectangular PCB Rogowski coils are composed of two parts, namely, a group A coil and a group B coil. Multiple coils in group A rotate horizontally around the center point of any rectangle in space and are evenly distributed at equal angles, and the coils in group B rotate three-dimensionally around one side of the rectangle and are evenly distributed at equal angles.

2. The detection device according to claim 1, wherein: Each rectangular PCB Rogowski coil contains two unidirectional unclosed coils. Connecting the ends of these two single-ended unclosed coils together forms a rectangular PCB Rogowski coil.

3. The detection device according to claim 1, characterized in that: The rectangular PCB Rogowski coil uses a rigid PCB form to form a rectangular contour, and the coil winding method inside is a parallel wire winding with uniform equal spacing.

4. The detection device according to claim 1, wherein: The number of coils in both group A and group B is one, which are a horizontal rectangular PCB Rogowski coil and a vertical rectangular PCB Rogowski coil respectively.

5. The detection device according to claim 1, characterized in that: The rectangular PCB Rogowski coil adopts a parallel double-wire winding mode.

6. The detection device according to claim 1, characterized in that: There is a copper-clad interlayer in the middle of the front and back of the PCB board of the Rogowski coil.

7. The detection device according to claim 6, characterized in that: The interlayer is embedded between the front Rogowski coil wiring and the back Rogowski coil wiring; the interlayer is a thin metal sheet with the function of shielding the electric field but not the magnetic field.

8. The detection device according to claim 1, characterized in that: The signal acquisition module enables the multiple rectangular PCB Rogowski coils to collect signals with different amplitudes by induction and then send them to the signal processing module through twisted pairs.

9. The detection device according to claim 1, wherein: The function of the signal processing module is to input the collected DC and AC signals into the analog signal sampling terminal of the MCU after passing the output signal of the rectangular PCB Rogowski coil through an operational amplifier, an active filter, and a low-pass filter.

10. A method for indirectly positioning the direction of a live wire, comprising the detection device according to any one of claims 1-9, characterized in that: It includes the following steps: Step 1: Turn on the power supply of the load line to be detected. Step 2: Place the detection device near the area where the wire may exist and first obtain a sampling value in the X direction with a certain amplitude. Step 3: According to the "arrow" direction prompt displayed on the detection device, the operator holds the detection device and moves it in the direction where the maximum induction value in the X-axis direction exists; stop moving when the X-axis value no longer changes. Step 4: The internal motor rotates automatically to rotate the measurement coil combination device by 90° and adjust the position of the rectangular coil combination. Step 5: Translate the measurement device left and right along the Z-axis direction at the same position; when, during the movement, the induction value of the Z-axis coil reaches the maximum and the induction value of the X-axis coil reaches the minimum, it indicates that the direction of the adjacent coil is parallel to the X-axis and perpendicular to the Z-axis; at this time, the wire is located directly below the X rectangular coil.

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