Auxiliary device and measurement method for accurate alignment measurement of three-dimensional power frequency magnetic field

Abstract

A three-dimensional power frequency magnetic field accurate alignment auxiliary measurement device and method are disclosed. The measurement auxiliary device consists of a measurement support, a Z-direction height compensation plate, and a planar positioning plate. The measurement support consists of a support base plate, a support column, and a measurement platform. A height-adjusting plate is attached to the support column to adjust and fix the height of the measurement platform. The Z-direction height compensation plate is placed between the measurement platform and the planar positioning plate to compensate for the height of the X and Y direction sensors when measuring the X and Y direction magnetic field components. This invention can conveniently achieve accurate alignment for the measurement of three-dimensional power frequency magnetic field components at the same point, enabling the sensor centers in each direction of the power frequency magnetic field measuring instrument to be precisely positioned at the measurement point, and accurately obtaining the power frequency magnetic field value at the measurement point.

Description

Technical Field

[0001] This invention relates to power frequency magnetic field measurement, and in particular to an auxiliary device and method for accurate alignment measurement of three-dimensional power frequency magnetic fields. Background Technology

[0002] As people's living standards improve and public awareness of environmental protection increases, the power frequency electromagnetic field environment around power transmission and transformation equipment has become a matter of public concern. In the study of power frequency magnetic fields and electromagnetic environment monitoring around power transmission and transformation facilities, it is essential to accurately measure the power frequency magnetic field at the monitoring point to determine whether the environment meets the relevant standard limits.

[0003] Since a power frequency magnetic field is a three-dimensional vector, the principle of a commonly used power frequency magnetic field measuring instrument is to arrange three independent sensors (measuring coils) in the X, Y, and Z directions within the instrument. These sensors measure the magnetic induction density components in each of the three directions, and then calculate the total magnetic induction density at the measured point. Because the X, Y, and Z direction sensors are positioned at different locations within the instrument, their centers cannot be simultaneously aligned with the measured point. In cases where the power frequency magnetic field is uniformly distributed or slightly non-uniformly distributed, the instrument is typically centered on the measured point, and the values ​​of the three directional components and the total value are read as the power frequency magnetic field value at that point. However, in non-uniform field measurements, this simplified method introduces significant measurement errors. Therefore, it is necessary to move the instrument position separately for each directional component measurement, aligning the center of the corresponding sensor with the measured point each time, to measure the three components at the same measured point. The total magnetic field at the measured point can then be calculated based on the three directional components. Because the measuring instrument cannot be turned on during measurement, it is difficult to accurately align it. Furthermore, there is a lack of accurate, convenient, and reliable alignment methods and auxiliary devices for moving the measuring instrument, resulting in long on-site measurement times and a high risk of measurement deviations due to operation. Summary of the Invention

[0004] The purpose of this invention is to overcome the difficulties in accurately measuring three-dimensional non-uniform power frequency magnetic fields in the field and laboratory, and to provide an auxiliary device and method for accurate alignment measurement of three-dimensional power frequency magnetic fields. This device can ensure that the three directional sensors inside the power frequency magnetic field measuring instrument are aligned with the same measurement point, thereby improving the efficiency and accuracy of measuring three-dimensional non-uniform power frequency magnetic fields in the field and laboratory.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device is characterized in that it consists of a measuring bracket, a Z-direction height adjustment plate, and a planar positioning plate. The measuring bracket comprises a base plate, a support column, and a measuring platform. A height adjustment plate is attached to the support column, and a fixing pin is used to adjust and fix the height of the measuring platform. The planar positioning plate has X-direction, Y-direction, and Z-direction slots, as well as positioning pin holes. Positioning pins pass through these holes to lock the relative position between the planar positioning plate and the measuring platform. All materials used in the measurement auxiliary device are non-metallic and non-magnetic. The positional relationships of the above components are as follows:

[0007] 1) Based on the relative positions of the X, Y, and Z direction sensors inside the power frequency magnetic field measuring instrument, with the center position of the X direction sensor as the origin O(0, 0, 0) of the three-dimensional coordinate system, and the directions pointed to by the X, Y, and Z direction sensors as the X-axis, Y-axis, and Z-axis directions respectively, determine the coordinates Yc(x) of the center position of the Y direction sensor. y ,y y The coordinates of the sensor center position in the Z direction are Zc(x, 0). z ,y z ,z z The distances of the left, right, top, and bottom edges of the power frequency magnetic field measuring instrument (11) from the origin of the coordinate system are y. l y r x u x d The distance z from the center position of the X-direction sensor to the bottom surface of the measuring instrument is determined. b ;

[0008] 2) The planar positioning plate is located in the xy plane, and its planar dimensions are slightly larger than the surface dimensions of the power frequency magnetic field measuring instrument. An origin O'(0,0) is marked on the planar positioning plate, and y = y is marked. r The right side of the line and x = -x u The upper edge of the top edge, and using the right edge and the upper edge as the inner edge, set the X-direction slot; calibrate y = -(y y +y l The left edge of the line and x = -x y +x d The bottom edge of the left and bottom edges are used as the inner edges to set the Y-direction slot; y = -(y z +y l The left edge of the line and x = -(x) u +x z The upper edge of the left and upper edges are used as the inner edges to set the Z-direction slot;

[0009] 3) The planar dimensions of the Z-direction height-increasing plate are slightly smaller than those of the planar positioning plate, and the thickness is equal to z. z;

[0010] 4) The measuring platform has a certain area to stably place the Z-direction height-adding plate and the planar positioning plate;

[0011] 5) The planar positioning plate and the measuring platform are stacked in parallel. At least one positioning pin hole is drilled on each side of the planar positioning plate to penetrate the measuring platform. Positioning pins are inserted to fix the relative position between the planar positioning plate and the measuring platform. The length of the positioning pin is greater than the sum of the thicknesses of the planar positioning plate, the measuring platform, and the Z-direction heightening plate. The spacing between the positioning pins is wider than the width between the two sides of the Z-direction heightening plate so that the Z-direction heightening plate can be easily pulled out from between the planar positioning plate and the measuring platform when measuring the Z-direction magnetic field component.

[0012] The method for measuring a three-dimensional power frequency magnetic field using the aforementioned three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device is characterized by the following steps:

[0013] 1) Determine the location of the point P to be measured for the three-dimensional power frequency magnetic field. Align the two adjacent sides of the measuring bracket with the X and Y directions respectively, and adjust the upper plane of the measuring platform to (z... p -z b -z c -z z The height of the measuring platform is determined by a height-adjusting plate and a fixing pin; wherein, z p z is the height of the measured point P above the ground. b z is the distance from the center of the X-axis sensor to the bottom surface of the measuring instrument. c Z represents the thickness of the planar positioning plate. z To increase the thickness of the plate in the Z direction;

[0014] 2) Place the Z-direction height-increasing plate flat on the measuring platform, then place the planar positioning plate flat on the Z-direction height-increasing plate, and insert positioning pins to fix the relative position between the planar positioning plate and the measuring platform; place the power frequency magnetic field measuring instrument flat on the planar positioning plate, with the upper right edge of the power frequency magnetic field measuring instrument tightly against the X-direction slot, and measure and record the magnetic induction density B in the X-direction. x ;

[0015] 3) Place the lower left side of the power frequency magnetic field measuring instrument against the Y-direction slot, measure and record the magnetic induction density B in the Y-direction. y ;

[0016] 4) Remove the Z-direction height-adding plate, place the upper left side of the power frequency magnetic field measuring instrument tightly against the Z-direction slot, and measure and record the magnetic induction density B in the Z-direction. z ;

[0017] 5) Calculate the magnetic flux density at the measured point P using the following formula:

[0018]

[0019] The beneficial effects of this invention are:

[0020] The measuring bracket of this invention consists of a base plate, a support column, and a measuring platform. A height adjustment plate is attached to the support column to adjust and fix the height of the measuring platform. The Z-direction height adjustment plate is placed between the measuring platform and the planar positioning plate to compensate for the height of the X and Y direction sensors when measuring the X and Y direction magnetic field components. The planar positioning plate has X-direction, Y-direction, and Z-direction slots, as well as positioning pin holes. The positioning pin holes are used for positioning and locking the relative position between the planar positioning plate and the measuring platform. When measuring the X, Y, and Z direction magnetic field components, the upper right, lower left, and upper left edges of the power frequency magnetic field measuring instrument are respectively pressed against the X-direction, Y-direction, and Z-direction slots to easily achieve accurate alignment for measuring the three-dimensional power frequency magnetic field components at the same point. This ensures that the center of the sensor in each direction of the power frequency magnetic field measuring instrument is precisely positioned at the measurement point, resulting in more accurate power frequency magnetic field values ​​at the measurement point. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the internal sensor arrangement of a three-dimensional power frequency magnetic field measuring instrument, where (a) is a three-dimensional schematic diagram and (b) is a top view schematic diagram.

[0022] Figure 2 This is a front view of the three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device of the present invention.

[0023] Figure 3 Schematic diagram of a planar positioning plate

[0024] Figure 4 Schematic diagram of the positioning movement of the power frequency magnetic field measuring instrument

[0025] Figure 5 The images shown are actual photographs of a specific embodiment, where (a) is the X-direction component measurement; (b) is the Y-direction component measurement; (c) is the Z-direction component measurement; and (d) is the planar positioning plate. Detailed Implementation

[0026] The method of the present invention will now be described in detail with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope or application of the present invention.

[0027] Figure 1The diagram shows the sensor arrangement in the X, Y, and Z directions inside a three-dimensional power frequency magnetic field measuring instrument. The sensors in the three directions are not in the same position. Since the magnetic field varies with position in a non-uniform magnetic field, the measuring instrument should be moved when measuring the power frequency magnetic field components in the three directions so that the center points of the corresponding measuring sensors are all located at the point being measured.

[0028] The front view of the three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device of the present invention is shown below. Figure 2 As shown in the figure, the three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device of the present invention consists of a measuring bracket, a Z-direction height adjustment plate 6, and a planar positioning plate 7. The measuring bracket consists of a bracket base plate 1, a support column 2, and a measuring platform 3. A height adjustment plate 4 is attached to the support column 2, and the height of the measuring platform 3 is adjusted and fixed by a fixing pin 5. The planar positioning plate 7 has an X-direction slot 9, a Y-direction slot 10, and a Z-direction slot 12, as well as a positioning pin hole. The relative position between the planar positioning plate 7 and the measuring platform 3 is locked by a positioning pin 8 passing through the positioning pin hole. All materials of the measuring auxiliary device are non-metallic and non-magnetic materials. The positional relationship of the above components is as follows:

[0029] 1) Based on the relative positions of the X, Y, and Z direction sensors inside the power frequency magnetic field measuring instrument 11, and taking the center position of the X direction sensor as the origin O(0, 0, 0) of the three-dimensional coordinate system, and the directions pointed to by the X, Y, and Z direction sensors as the X-axis, Y-axis, and Z-axis directions respectively, determine the coordinates Yc(x) of the center position of the Y direction sensor. y ,y y The coordinates of the sensor center position in the Z direction are Zc(x, 0). z ,y z ,z z The distances of the left, right, top, and bottom edges of the power frequency magnetic field measuring instrument (11) from the origin of the coordinate system are y. l yr, x u x d The distance z from the center position of the X-direction sensor to the bottom surface of the measuring instrument is determined. b ;

[0030] 2) The planar positioning plate 7 is located in the xy plane, and its planar dimensions are slightly larger than the surface dimensions of the power frequency magnetic field measuring instrument. An origin O'(0,0) is marked on the planar positioning plate 7, and y = y is marked. r The right side of the line and x = -x u The upper edge of the top edge, and with the right edge and the upper edge as the inner edge, set the X-direction slot 9; calibrate y = -(y y +y l The left edge of the line and x = -x y +x dThe lower edge line, and with the left edge line and the lower edge line as the inner edge, set the Y-direction slot 10; calibrate y = -(y z +y l The left edge of the line and x = -(x) u +x z The upper edge of the left and upper edges are used as the inner edges to set the Z-direction slot 12;

[0031] 3) The planar dimensions of the Z-direction height-increasing plate 6 are slightly smaller than those of the planar positioning plate 7, and its thickness is equal to that of the Z-direction height-increasing plate 6. z ;

[0032] 4) The measuring platform 3 has a certain area to stably place the Z-direction height-adding plate 6 and the planar positioning plate 7;

[0033] 5) The planar positioning plate 7 and the measuring platform 3 are stacked in parallel. At least one positioning pin hole is drilled on each side of the planar positioning plate 7 to penetrate the measuring platform 3. Positioning pins 8 are inserted to fix the relative position between the planar positioning plate 7 and the measuring platform 3. The length of the positioning pin 8 is greater than the sum of the thicknesses of the planar positioning plate 7, the measuring platform 3 and the Z-direction heightening plate 6. The spacing between the positioning pins 8 is wider than the width between the two sides of the Z-direction heightening plate 6 so that the Z-direction heightening plate 6 can be easily pulled out from between the planar positioning plate 7 and the measuring platform 3 when measuring the Z-direction magnetic field component.

[0034] The method for measuring a three-dimensional power frequency magnetic field using the aforementioned three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device comprises the following steps:

[0035] 1) Determine the location of the point P to be measured for the three-dimensional power frequency magnetic field. Align the two adjacent sides of the measuring bracket with the X and Y directions respectively, and adjust the upper plane of the measuring platform 3 to (z... p -z b -z c -z z The height is determined by fixing the measuring platform 3 with the height plate 4 and the fixing pin 5; where z p z is the height of the measured point P above the ground. b z is the distance from the center of the X-axis sensor to the bottom surface of the measuring instrument. c The thickness of the planar positioning plate 7, z z To increase the thickness of plate 6 in the Z direction;

[0036] 2) Place the Z-direction height-increasing plate 6 flat on the measuring platform 3, then place the planar positioning plate 7 flat on the Z-direction height-increasing plate 6, and insert the positioning pin 8 to fix the relative position between the planar positioning plate 7 and the measuring platform 3; place the power frequency magnetic field measuring instrument 11 flat on the planar positioning plate 7, and place the upper right side of the power frequency magnetic field measuring instrument 11 against the X-direction slot 9, measure and record the magnetic induction density B in the X direction. x ;

[0037] 3) Place the lower left side of the power frequency magnetic field measuring instrument 11 against the Y-direction slot 10, measure and record the magnetic induction density B in the Y direction. y ;

[0038] 4) Remove the Z-direction height-adding plate 6, place the upper left side of the power frequency magnetic field measuring instrument 11 tightly against the Z-direction slot 12, and measure and record the magnetic induction density B in the Z-direction. z ;

[0039] 5) Calculate the magnetic flux density at the measured point P using the following formula:

[0040]

[0041] The following example uses the FieldStar power frequency magnetic field measuring instrument to demonstrate how the measurement auxiliary device of this invention can be used to achieve accurate alignment of the three-dimensional power frequency magnetic field component measurement at the same point. This allows the sensor centers of the FieldStar power frequency magnetic field measuring instrument in each direction to be precisely located at the measurement point, thus obtaining the power frequency magnetic field value at the measurement point more accurately. Figure 5 Here is a photograph of the actual product in this specific embodiment. The specific implementation steps are as follows (all data are in cm):

[0042] 1. Based on the relative positions of the X, Y, and Z direction sensors inside the FieldStar power frequency magnetic field measuring instrument, with the center position of the X direction sensor as the origin O(0,0,0) of the three-dimensional coordinate system, and the directions pointed to by the X, Y, and Z direction sensors as the X-axis, Y-axis, and Z-axis directions respectively, determine the coordinates Yc(-5.55,5.55,0) of the center position of the Y direction sensor, the coordinates Zc(1.05,7.35,0.7) of the center position of the Z direction sensor, and the distances y from the left, right, top, and bottom edges of the power frequency magnetic field measuring instrument to the origin of the coordinate system. l =1.35, y r =8.8, x u =6.9, x d =12.25. Determine the distance z from the center position of the X-direction sensor to the bottom surface of the measuring instrument. b =2.05.

[0043] 2. Fabricate a piece of epoxy board as follows: Figure 5(d) The planar positioning plate 7 (xy plane) shown has a planar dimension slightly larger than the surface dimension of the power frequency magnetic field measuring instrument. An origin O'(0,0) is marked on the planar positioning plate, and y = y is calibrated. r =8.8 and the right edge of the line and x = -x u = -6.9, and set the X-direction slot 9 with the right and top edges as the inner edges. Calibrate y = -(y y +y l The left edge of ) = -6.9 and x = -x y +x d =17.8, and set the Y-direction slot 10 with the left and bottom edges as the inner edges. Calibrate y = -(y z +y l The left edge of ) = -8.7 and x = -(x u +x z The upper edge of the Z-direction slot 12 is set with the left and upper edges as the inner edges.

[0044] 3. Fabricate a Z-direction heightening plate 6 using dried epoxy board. The planar dimensions of the plate are slightly smaller than the planar positioning plate, and the thickness is equal to the Z-direction heightening plate. z =0.7.

[0045] 4. Make a measuring stand using dry wooden boards. The measuring stand consists of a base plate 1, a support column 2, and a measuring platform 3. The support column is equipped with a height adjustment plate 4 (made of epoxy board) to adjust and fix the height of the measuring platform 3. The measuring platform 3 has a certain area to stably place the Z-direction height adjustment plate 6 and the plane positioning plate 7.

[0046] 5. The planar positioning plate 7 and the measuring platform 3 are stacked in parallel. At least one positioning pin hole is drilled on each side of the planar positioning plate 7, penetrating the measuring platform. After inserting a positioning pin 8 made of non-magnetic, non-metallic material, the relative position between the planar positioning plate 7 and the measuring platform 3 can be fixed. The length of the positioning pin 8 is greater than the sum of the thicknesses of the planar positioning plate, the measuring platform, and the Z-direction elevation plate. The spacing between the positioning pins is wider than the width of one side of the Z-direction elevation plate, so that when measuring the Z-direction magnetic field component, the Z-direction elevation plate 6 can be easily pulled out from between the planar positioning plate 7 and the measuring platform 3.

[0047] The steps for conducting actual measurements using the three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device of the above embodiment are as follows (all data are in centimeters):

[0048] 1. Determine the location of the point P to be measured in the three-dimensional power frequency magnetic field. Align the two sides of the measuring bracket with the X and Y directions, and adjust the upper plane of the measuring platform to (z... p -z b -z c -zz The height is 81.25, and is fixed by a height-adjusting plate attached to the measuring bracket. Where z p =85 is the height of the measured point from the ground, z b =2.05 is the distance from the center of the X-direction sensor to the bottom surface of the measuring instrument, z c =1 represents the thickness of the planar positioning plate, z z =0.7 represents the thickness of the height-adding plate in the Z direction.

[0049] 2. Place the Z-direction heightening plate 6 flat on the measuring platform 3, then place the planar positioning plate 7 flat on the Z-direction heightening plate 6, and insert the positioning pin 8 to fix the relative position between the planar positioning plate 7 and the measuring platform 3. The power frequency magnetic field measuring instrument 11 is placed flat on the planar positioning plate 7, as follows: Figure 5 As shown in (a), the upper right side of the power frequency magnetic field measuring instrument 11 is placed close to the X-direction slot 9 to measure and record the magnetic induction density B in the X-direction. x ;

[0050] 3. For example Figure 5 As shown in (b), the lower left side of the power frequency magnetic field measuring instrument is placed close to the Y-direction slot 10, and the magnetic induction density B in the Y direction is measured and recorded. y ;

[0051] 4. For example Figure 5 As shown in (c), remove the Z-direction height-adding plate 6, place the upper left side of the power frequency magnetic field measuring instrument tightly against the Z-direction slot 12, and measure and record the magnetic induction density B in the Y direction. z .

[0052] 5. Obtain the three components B of the power frequency magnetic field. X B Y B Z After taking the reading, the three-dimensional power frequency magnetic field at the measurement point can be calculated:

[0053]

[0054] The power frequency magnetic field at three measurement points near a current-carrying cable was measured using this measurement auxiliary device embodiment. The measurement data and results are shown in the table below (magnetic induction density unit: μT, the data in bold in the table are the magnetic field component readings when the sensor is aligned with the measurement point in the corresponding direction and the total magnetic field measured according to the method of the present invention).

[0055]

[0056] * Note: When measuring the Z component with the measuring instrument close to the Z-direction slot, remove the Z-direction height compensation plate.

[0057] Analysis of the data in the table above shows that there is a significant difference between the power frequency magnetic field data measured using the method of this invention and the total magnetic field data directly displayed by the measuring instrument. This invention can solve the problem of accurate positioning in the measurement of three-dimensional magnetic field components at the same point. The measurement auxiliary device is convenient to use and can more accurately measure the magnetic field components in each direction at the measurement point.

[0058] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device, characterized in that, The device consists of a measuring bracket, a Z-direction height adjustment plate (6), and a planar positioning plate (7). The measuring bracket consists of a bracket base plate (1), a support column (2), and a measuring platform (3). The support column (2) is equipped with a height adjustment plate (4), and the height of the measuring platform (3) is adjusted and fixed by a fixing pin (5). The planar positioning plate (7) has an X-direction slot (9), a Y-direction slot (10), and a Z-direction slot (12), as well as a positioning pin hole. The positioning pin (8) passes through the hole and locks the relative position between the planar positioning plate (7) and the measuring platform (3). The measuring bracket is made of wood. All materials of the measuring auxiliary device are non-metallic and non-magnetic. The positional relationship of the above components is as follows: 1) Based on the relative positions of the X, Y, and Z direction sensors inside the power frequency magnetic field measuring instrument (11), with the center position of the X direction sensor as the origin O(0, 0, 0) of the three-dimensional coordinate system, and the directions pointed to by the X, Y, and Z direction sensors as the X-axis, Y-axis, and Z-axis directions respectively, determine the coordinates Yc(x) of the center position of the Y direction sensor. y ,y y The coordinates of the sensor center position in the Z direction are Zc(x, 0). z ,y z ,z z The distances of the left, right, top, and bottom edges of the power frequency magnetic field measuring instrument (11) from the origin of the coordinate system are y. l y r x u x d The distance z from the center position of the X-direction sensor to the bottom surface of the measuring instrument is determined. b ; 2) The planar positioning plate (7) is located in the xy plane, and its planar dimensions are slightly larger than the surface dimensions of the power frequency magnetic field measuring instrument. An origin O'(0,0) is marked on the planar positioning plate (7), and y = y is marked. r The right side of the line and x = -x u The upper edge of the top edge, and the right edge and the upper edge of the top edge are used as the inner edges to set the X-direction slot (9); calibrate y = -(y y +y l The left edge of the line and x = -x y +x d The lower edge of the left and lower edges are used as the inner edges to set a Y-direction slot (10); y = -(y z +y l The left edge of the line and x = -(x) u +x z The upper edge of the left and upper edges of the left edge and the upper edge are used as the inner edges to set the Z-direction slot (12); 3) The planar dimensions of the Z-direction height-adding plate (6) are slightly smaller than those of the planar positioning plate (7), and the thickness is equal to the z-direction height-adding plate (6). z ; 4) The measuring support (2) is equipped with a height-adjusting plate (4) which can adjust and fix the height of the measuring platform (3). The measuring platform (3) has a certain area to stably place the Z-direction height-adjusting plate (6) and the planar positioning plate (7). 5) The planar positioning plate (7) and the measuring platform (3) are stacked in parallel. At least one positioning pin hole is drilled on each side of the planar positioning plate (7) to penetrate the measuring platform (3). Positioning pins (8) are inserted to fix the relative position between the planar positioning plate (7) and the measuring platform (3). The length of the positioning pin (8) is greater than the sum of the thicknesses of the planar positioning plate (7), the measuring platform (3) and the Z-direction heightening plate (6). The spacing between the positioning pins (8) is wider than the width between the two sides of the Z-direction heightening plate (6) so that the Z-direction heightening plate (6) can be easily pulled out between the planar positioning plate (7) and the measuring platform (3) when measuring the Z-direction magnetic field component.

2. A method for measuring a three-dimensional power frequency magnetic field using the three-dimensional power frequency magnetic field accurate alignment measurement auxiliary device as described in claim 1, characterized in that... The steps of this measurement method are as follows: 1) Determine the location of the point P to be measured for the three-dimensional power frequency magnetic field. Align the two adjacent sides of the measuring bracket with the X and Y directions respectively, and adjust the upper plane of the measuring platform (3) to (z p -z b -z c -z z The height of the measuring platform (3) is fixed by means of a height plate (4) and a fixing pin (5); wherein, z p z is the height of the measured point P above the ground. b z is the distance from the center of the X-axis sensor to the bottom surface of the measuring instrument. c The thickness of the planar positioning plate (7), z z The thickness of the plate (6) in the Z direction is increased; 2) Place the Z-direction height-increasing plate (6) flat on the measuring platform (3), and then place the planar positioning plate (7) flat on the Z-direction height-increasing plate (6). Insert the positioning pin (8) to fix the relative position between the planar positioning plate (7) and the measuring platform (3). Place the power frequency magnetic field measuring instrument (11) flat on the planar positioning plate (7), and place the upper right side of the power frequency magnetic field measuring instrument (11) close to the X-direction slot (9). Measure and record the magnetic induction density B in the X direction. x ; 3) Place the lower left side of the power frequency magnetic field measuring instrument (11) against the Y-direction slot (10), measure and record the magnetic induction density B in the Y direction. y ; 4) Remove the Z-direction heightening plate (6) between the measuring platform (3) and the planar positioning plate (7), and place the upper left side of the power frequency magnetic field measuring instrument (11) tightly against the Z-direction slot (12), measure and record the magnetic induction density B in the Z-direction. z ; 5) Calculate the magnetic flux density at the measured point P using the following formula:

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