Ray three-dimensional imaging measuring device and method for internal structure of gas insulated electrical equipment in service state

Abstract

The invention discloses a ray three-dimensional imaging measuring device and method for an internal structure of gas insulated electrical equipment in a service state, and relates to the field of high-voltage power grids, and the device comprises a first track and a second track which are detachable and parallel in the horizontal direction and are arranged between two supporting portal frames; the first track can be disassembled into two parts; the first rail and the second rail are made of aluminum alloy materials. Two ends of the ray machine are respectively fixed on the first ray machine adapter table and the second ray machine adapter table; an imaging transfer table is arranged on the first track, an imaging plate is arranged on the imaging transfer table, and the difference between the imaging plate and the ray machine is 180 degrees; and the imaging system reconstructs a ray three-dimensional image of the internal structure of the gas insulated electrical equipment in a service state according to the scanning track and the received multi-angle ray image on the imaging plate. The size and the weight of the device can be reduced, CT flaw detection on the gas insulation electrical equipment under the actual on-site service condition is achieved, and the detection effect is improved.

Description

Technical Field

[0001] The present application relates to the field of high-voltage power grids, and in particular to a device and method for measuring the internal structure of a gas-insulated electrical device under service by three-dimensional ray imaging. Background Art

[0002] Gas-insulated transmission line (GIL) is a key equipment for high-voltage power transmission. The integrity of its internal structure is crucial to the stable operation of the power system. However, traditional GIL detection methods usually require dismantling the equipment or interrupting the power supply, which not only affects the normal operation of the power system but also may bring safety hazards. Therefore, it is of great significance to develop an industrial CT system that can detect the internal structure of GIL in situ under energized state.

[0003] Although X-ray photography has played a revolutionary role in diagnosis and detection, the image of the interior of a three-dimensional object obtained by X-ray imaging is two-dimensional, and the information in the depth direction overlaps. On the one hand, it is impossible to determine the specific position information, and on the other hand, the contrast is reduced.

[0004] The existing DR detection method that can achieve three-dimensional imaging is limited by digital X-ray imaging, and the detection effect of cracks and pores with narrow width and shallow depth is poor. The gas-insulated switchgear 3D imaging system developed based on robots has a large volume and weight of the entire imaging system, and the overall equipment is difficult to disassemble, which makes it difficult to apply CT flaw detection to gas-insulated electrical equipment under actual service conditions on site. Summary of the invention

[0005] The purpose of the present application is to provide a three-dimensional radiographic imaging measurement device and method for the internal structure of a gas-insulated electrical device in service, so as to solve the problems of poor detection effect, heavy weight, difficulty in disassembly, and inability to perform CT flaw detection on gas-insulated electrical equipment under actual service conditions on site in traditional three-dimensional imaging measurement methods.

[0006] To achieve the above objectives, this application provides the following solutions:

[0007] In a first aspect, the present application provides a three-dimensional radiographic imaging measurement device for the internal structure of a gas-insulated electrical device in service, comprising: a supporting gantry, a first track, a second track, a first radiographic machine transfer platform, a second radiographic machine transfer platform, a radiographic machine, and an imaging system;

[0008] The supporting gantries include two, and the first rail and the second rail are arranged in parallel in the horizontal direction between the two supporting gantries; the first rail and the second rail are detachable rails, wherein the first rail can be disassembled into two parts; the first rail and the second rail are made of aluminum alloy material;

[0009] The first X-ray machine transfer platform is arranged at the bottom of the first track, the second X-ray machine transfer platform is arranged at the bottom of the second track, and two ends of the X-ray machine are respectively fixed on the first X-ray machine transfer platform and the second X-ray machine transfer platform; the first X-ray machine transfer platform and the second X-ray machine transfer platform are respectively driven by two first servo motors; the two first servo motors rotate synchronously;

[0010] The first track is provided with an imaging transfer platform, the imaging transfer platform is provided with an imaging plate, and the imaging plate is 180° away from the ray machine; the imaging transfer platform is driven by a second servo motor; the second servo motor rotates synchronously with the first servo motor;

[0011] The imaging system is used to reconstruct a three-dimensional radiographic image of the internal structure of the gas-insulated electrical equipment in service according to the scanning trajectory of the radiographic machine and based on the multi-angle radiographic images received on the imaging plate, so as to achieve three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

[0012] Optionally, the supporting gantry specifically comprises: a threaded support column and a supporting gantry screw rod;

[0013] The threaded support column and the supporting gantry screw rod are arranged in parallel in the vertical direction;

[0014] A lead screw supporting the gantry on one side is connected to the first rail and the second rail respectively through a sliding bracket, and a lead screw supporting the gantry on the other side is connected to the first rail through a sliding bracket; a third servo motor is provided on the sliding bracket; the third servo motor is used to drive the first rail and the second rail to rise and fall on the lead screw supporting the gantry.

[0015] Optionally, the arc of the first track is 360°, and the arc of the second track is 150°.

[0016] Optionally, each time the first servo motor rotates a set angle within a set angle range, the X-ray machine performs X-ray fluoroscopic imaging.

[0017] Optionally, the radiation voltage range of the radiation machine is 150kV-300kV.

[0018] Optionally, the set angle range is 0°-3°.

[0019] In a second aspect, the present application further provides a three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service, wherein the three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service is applied to the three-dimensional ray imaging measurement device for the internal structure of a gas-insulated electrical device in service, and the three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service comprises:

[0020] A circular trajectory is set according to the first trajectory and the second trajectory, a connecting line of the range of interest of the circular trajectory is used as a reconstruction range for scanning, and a multi-angle radiation image on the imaging plate is obtained according to the scanning trajectory of the radiation machine;

[0021] A circular trajectory back-projection function is used to perform three-dimensional reconstruction on the ray image at each angle in the multi-angle ray image, and the fan-shaped reflection imaging data in the ray image at each angle is rearranged into fence-shaped parallel projection data;

[0022] Performing Hilbert transformation on the parallel projection data to generate transformed parallel projection data;

[0023] Determine the density probability of the reconstructed unit within the reconstruction range according to all transformed parallel projection data;

[0024] A final three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment in service is constructed according to the density probability of the reconstructed unit.

[0025] Optionally, the circular trajectory back projection function for:

[0026]

[0027] in, is the scanning trajectory; R is the scanning trajectory radius; is the unit vector of the rotating coordinate system, and the rotating coordinate system is a rotating coordinate system with the ray machine as the origin; S is the distance between the imaging plate and the light source; P(u d ,v d ,λ) is the projection angle λ The projection on the detector, For any point on the trajectory, (u d ,v d ) is the projection angle λ The projection coordinates on the detector; A is a simplified formula and has no practical meaning. λ1 is the first projection angle; λ2 is the second projection angle.

[0028] Optionally, the transformed parallel projection data for:

[0029]

[0030] in, P(θ,t,s) represents the projection value under the virtual detector. represents any point on the PI line, which is the line segment between the two ray source points. The angle between the origin of the coordinate system and the y-axis, t is the angle between The distance from the coordinate system to the origin is recorded as s is the virtual detector The projection value in the z-axis direction.

[0031] β and R represent the rotation angle and the distance from the light source to the rotation axis, respectively. Then the data P(θ, t, s) on the virtual detector can all be represented by known parameters to achieve projection data rearrangement. The rearrangement formula is:

[0032]

[0033] Optionally, the density probability of the reconstructed unit within the reconstruction range for:

[0034]

[0035] Among them, x′ c Point on the PI segment Another form of expression (so g(x′ c ) is equivalent to x c1 , x c2 are the two endpoints of the PI segment, C is a constant, x c is the coordinate of the midpoint of the chord segment, x c ∈[x c1 , x c2 ].

[0036] According to the specific embodiments provided by the present application, the present application discloses the following technical effects: the present application provides a three-dimensional X-ray imaging and measuring device for the internal structure of a gas-insulated electrical device in service. By setting two detachable tracks, in order to improve the disassembly efficiency, the first track with an arc of 360° is disassembled into a track that can be disassembled into two parts, and aluminum alloy material is used as the material of the two tracks, thereby achieving a lightweight design and reducing the volume and weight of the device; due to the lightweight design of the track, it is easier for operators to install, thereby realizing CT flaw detection of gas-insulated electrical equipment under actual service conditions on site.

[0037] In addition, the present application also provides a method for measuring the internal structure of gas-insulated electrical equipment in service by three-dimensional X-ray imaging. A circular trajectory is set according to the first trajectory and the second trajectory, and the connecting line of the range of interest of the circular trajectory is used as the reconstruction range for scanning. According to the scanning trajectory of the X-ray machine, a multi-angle X-ray image is obtained on the imaging plate, and the density probability of the reconstructed unit within the reconstruction range is determined by using a circular trajectory back-projection function, a Hilbert transform, and the like, so as to construct a final three-dimensional reconstructed image of the internal structure of the gas-insulated electrical equipment in service. The method is not limited by digital X-ray imaging, and can reconstruct a three-dimensional reconstructed image within any reconstruction range, thereby improving the detection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A stereoscopic image of the internal structure ray three-dimensional imaging measurement device of a gas-insulated electrical equipment in a service state at a first angle in a working state provided by the present application;

[0040] Figure 2 A stereoscopic image of the internal structure ray three-dimensional imaging measurement device of a gas-insulated electrical equipment in a service state at a second angle in a working state provided by the present application;

[0041] Figure 3 A stereoscopic image of the internal structure three-dimensional imaging measurement device of a gas-insulated electrical equipment in a disassembled state and in a service state at a first angle provided by the present application;

[0042] Figure 4 A stereoscopic image of the internal structure three-dimensional imaging measurement device of a gas-insulated electrical equipment in a disassembled state and in a service state from a second angle provided in the present application;

[0043] Figure 5 A flow chart of the method for measuring the internal structure of a gas-insulated electrical device in service using three-dimensional radiographic imaging provided in this application;

[0044] Figure 6 It is a top view of the coordinate relationship between the virtual detector and P(θ, t, s) on the z-axis;

[0045] Figure 7 It is a top view of the coordinate relationship between the virtual detector and P(θ, t, s) in the t-axis direction;

[0046] Figure 8Schematic diagram of the non-central plane projection coordinate system. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0049] Embodiment 1

[0050] like Figure 1-Figure 4 As shown, the present application provides a three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service, including: a supporting gantry 1, a first track 2, a second track 3, a first X-ray machine adapter, a second X-ray machine adapter, a X-ray machine 4 and an imaging system.

[0051] The supporting gantries 1 include two, and the first rail 2 and the second rail 3 are arranged parallel in the horizontal direction between the two supporting gantries 1; the curvature of the first rail 2 is 360°, and the curvature of the second rail 3 is 150°; the first rail 2 and the second rail 3 are detachable rails, wherein the first rail 2 can be disassembled into two parts; the material of the first rail 2 and the second rail 3 is aluminum alloy material.

[0052] The first X-ray machine transfer platform is arranged at the bottom of the first track 2, the second X-ray machine transfer platform is arranged at the bottom of the second track 3, and the two ends of the X-ray machine 4 are respectively fixed on the first X-ray machine transfer platform and the second X-ray machine transfer platform; the first X-ray machine transfer platform and the second X-ray machine transfer platform are respectively driven by two first servo motors; the two first servo motors rotate synchronously. In actual operation, the first X-ray machine transfer platform and the second X-ray machine transfer platform can be aluminum alloy plates under the X-ray machine 4.

[0053] The first track 2 is arranged on an imaging switching platform, on which an imaging plate 5 is arranged, and the imaging plate 5 is 180° away from the X-ray machine 4; the imaging switching platform is driven by a second servo motor; the second servo motor rotates synchronously with the first servo motor.

[0054] Furthermore, the first ray machine switching platform, the second ray machine switching platform and the imaging plate switching platform are fixed through a 180-degree arc, and the imaging plate switching platform is equipped with a second servo motor to keep synchronous rotation with the two first servo motors on the first ray switching platform or the second ray switching platform.

[0055] The imaging system is used to reconstruct a three-dimensional radiographic image of the internal structure of the gas-insulated electrical equipment in service according to the scanning trajectory of the radiographic machine 4 and based on the multi-angle radiographic images received on the imaging plate 5, so as to achieve three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

[0056] This application uses a relatively light high-strength aluminum alloy track. The overall size of the equipment is small and detachable, and can be disassembled and installed on site by 2-3 people.

[0057] Furthermore, the imaging system is a 120°-150° horizontal continuous X-ray imaging system, which collects multi-angle X-ray images and uses a local three-dimensional image reconstruction algorithm to accurately reconstruct the range of 120°-150°, thereby realizing three-dimensional measurement of the internal structure of electrical equipment.

[0058] In practical applications, the supporting gantry 1 specifically includes: a threaded support column 6 and a supporting gantry screw rod 7; the threaded support column 6 and the supporting gantry screw rod 7 are arranged in parallel in the vertical direction.

[0059] The lead screw supporting the gantry 1 on one side is connected to the first rail 2 and the second rail 3 respectively through the sliding bracket 8, and the lead screw supporting the gantry 1 on the other side is connected to the first rail 2 through the sliding bracket 8; a third servo motor is provided on the sliding bracket 8; the third servo motor is used to drive the first rail 2 and the second rail 3 to rise and fall on the lead screw supporting the gantry 1.

[0060] The three-dimensional X-ray imaging and measuring device for the internal structure of gas-insulated electrical equipment in service of the present application is adopted. On the one hand, since the detection object (gil pipeline) is a long pipeline with a large diameter, the complete ring cannot be directly inserted into the detection object. The present application is divided into two parts to realize on-site detection without disassembling the detection object; on the other hand, the reduced weight of the track can facilitate installation by the operating personnel.

[0061] In order to ensure the stability of the equipment and avoid mechanical errors caused by mechanical structure vibration, the thickness and width of the track cannot be too small; in addition, the track diameter exceeds 1m, which makes the track very heavy and difficult to operate on site. Splitting it into two halves can ensure that workers can install it at a high place during on-site operations.

[0062] The disassembly points of the first track 2 are at the top and bottom. The left and right positions of the first track 2 are connected to the lead screw supporting the gantry 1. A third servo motor is respectively arranged on the left and right brackets of the gantry. The third servo motor drives the first track 2 and the second to rise and fall.

[0063] The support gantries 1 on both sides provide support to maintain the stability of the present application; by setting the threaded bracket columns 6, the height of the support gantry 1 can be adjusted by turning the screws according to the on-site conditions, and then the support gantry 1 can be fixed.

[0064] In practical applications, each time the first servo motor rotates once by a set angle within a set angle range, the X-ray machine 4 performs X-ray fluoroscopic imaging once.

[0065] In practical applications, the radiation voltage range of the radiation generator 4 is 150 kV-300 kV.

[0066] In practical applications, the setting angle range is 0°-3°.

[0067] Embodiment 2

[0068] like Figure 5 As shown, the present application also provides a three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service, and the three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service is applied to the three-dimensional ray imaging measurement device for the internal structure of a gas-insulated electrical device in service, and the three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service comprises:

[0069] Step 501: a circular trajectory is set according to the first trajectory and the second trajectory, a connecting line of the range of interest of the circular trajectory is used as a reconstruction range for scanning, and a multi-angle X-ray image on the imaging plate is obtained according to the scanning trajectory of the X-ray machine.

[0070] Step 502: Use a circular trajectory back-projection function to perform three-dimensional reconstruction on the ray image at each angle in the multi-angle ray image, and rearrange the fan-shaped reflection imaging data in the ray image at each angle into fence-shaped parallel projection data.

[0071] In practical applications, the circular trajectory back projection function for:

[0072]

[0073] in, is the scanning trajectory, T is the transposition operation; R is the scanning trajectory radius; is the unit vector of the rotating coordinate system, and the rotating coordinate system is a rotating coordinate system with the ray machine as the origin; S is the distance between the imaging plate and the light source; P(ud ,v d ,λ) is the projection angle λ The projection on the detector, For any point on the trajectory, (u d ,v d ) is the projection angle λ The projection coordinates on the detector; A is a simplified formula and has no practical meaning. λ1 is the first projection angle; λ2 is the second projection angle; “|” is the definite integral symbol.

[0074] Step 503: Perform Hilbert transform on the parallel projection data to generate transformed parallel projection data.

[0075] In practical applications, the geometric relationship of circular trajectory cone beam scanning is first introduced: β and R represent the rotation angle and the distance from the light source to the rotation axis, respectively. In order to facilitate the description of the rearrangement formula, a virtual detector parallel to the real detector is introduced at the origin of the coordinate axis. P1(β, m, n) represents the data on the virtual detector, and (m, n) represents the coordinates on the virtual detector. In order to describe the rearranged parallel projection data, another virtual detector is introduced, and the projection on it is represented by P(θ, t, s), where, represents any point on the PI line. The PI line is the line segment between the two ray source points. θ is The angle between the origin of the coordinate system and the y-axis, t is the angle between The distance from the coordinate system to the origin is recorded as s is the virtual detector The projection value in the z-axis direction is as follows Figure 6-Figure 7 shown.

[0076]

[0077] Therefore, P1(β, m, n) can be rearranged into parallel data P(θ, t, s), and the rearrangement formula is as follows:

[0078]

[0079] The transformed parallel projection data for:

[0080]

[0081] in,

[0082] use Represents the density function of the reconstructed object, and there is a relationship:

[0083]

[0084] in express The Hibbert transform.

[0085] For any projection P(θ,t,s)(S≠0), A small rotation of the axis δθ and about A rotation of the axis δθ′ is equivalent, and they correspond to a similar arc length, so:

[0086]

[0087] Its coordinate system relationship is as follows Figure 8 As shown, the rotation axis is Axis, vector Parallel to the center plane, vector Tilt about the z-axis, and P and S represent a projection and a light source respectively. There are:

[0088]

[0089] in,

[0090] Step 504: Determine the density probability of the reconstructed unit within the reconstruction range according to all transformed parallel projection data.

[0091] In practical applications, for the back-projected values ​​of all points on the PI line segment, a finite Hibbert transform is performed to obtain an inverse transform, and the density probability of the reconstructed unit within the reconstruction range is for:

[0092]

[0093] Among them, x′ c Point on the PI segment Another form of expression (so g(x′ c ) is equivalent to ), x c1 , x c2 are the two endpoints of the PI segment, C is a constant, x c is the coordinate of the midpoint of the chord segment, x c ∈[x c1 , x c2 ]; C is a constant.

[0094] Step 505: construct a final three-dimensional reconstructed image of the internal structure of the gas-insulated electrical equipment in service according to the density probability of the reconstructed unit; the final three-dimensional reconstructed image of the internal structure of the gas-insulated electrical equipment in service is used to achieve three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

[0095] Based on the above-mentioned three-dimensional imaging measurement method for the internal structure of gas-insulated electrical equipment in service state of the present application, reconstruction is performed based on a line segment on the line connecting the 0° to 150° position on the scanning trajectory. In this example, the connecting line of the range of interest is the 0°-120° connecting line. The reconstruction method is as follows:

[0096] Step 1: Set the circular trajectory according to the rotation track, and use the 0°-120° connecting line as the reconstruction range, using the circular trajectory back-projection function Reconstruct the image within a certain angle.

[0097] The circular trajectory in this application is the scanning trajectory, which refers to the trajectory of the radiation source of the radiation machine 4 during the scanning process. The radiation source rotates a certain angle and continuously forms an image on the imaging plate 5, which records the scanning process of the radiation source. The image of each angle device is obtained through the imaging plate 5, and the three-dimensional image is reconstructed through the back projection function.

[0098] Step 2: Rearrange the fan-shaped reflection imaging data in the ray image at each angle into fence-shaped parallel projection data, and perform Hilbert transform on the parallel projection data.

[0099] Step 3: By scanning all transformed parallel projection data point by point and summing them up, we can get:

[0100]

[0101] in, represents any point on the PI line. The PI line is the line segment between the two ray source points. θ is The angle between the origin of the coordinate system and the y-axis, t is the angle between The distance from the coordinate system to the origin is recorded as s is the virtual detector Projection value in the z-axis direction. Non-central plane projection coordinate system see Figure 8 , the rotation axis is Axis, vector Parallel to the center plane, vector Tilt about the z-axis, and

[0102] for The coordinate axis obtained after rotation; The coordinate axis from the light source to the projection point.

[0103] Step 4: Use represents the density function of the reconstructed unit, You can get:

[0104]

[0105] In this embodiment, the key position of the accurately reconstructed 0-120° arc is used as the reference point, and the central axis of the internal conductor is used as the reference line, and the deviation between the designed three-dimensional graphics and the imaging structure of the detection object is measured along the circumferential direction and the axis; the present application can accurately image the structure outside the area and reconstruct it using the designed three-dimensional graphics.

[0106] The present application is lightweight, easy to disassemble and assemble, and can be assembled on site to achieve in-situ live detection and in-situ live CT imaging.

[0107] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A three-dimensional imaging measurement device for the internal structure of a gas-insulated electrical device in service, characterized in that: include: Supporting the gantry, the first track, the second track, the first X-ray machine transfer platform, the second X-ray machine transfer platform, the X-ray machine and the imaging system; The supporting gantries include two, and the first track and the second track parallel in the horizontal direction are arranged between the two supporting gantries; The first rail and the second rail are detachable rails, wherein the first rail can be disassembled into two parts; the first rail and the second rail are made of aluminum alloy material; The first X-ray machine transfer platform is arranged at the bottom of the first track, the second X-ray machine transfer platform is arranged at the bottom of the second track, and two ends of the X-ray machine are respectively fixed on the first X-ray machine transfer platform and the second X-ray machine transfer platform; The first X-ray machine switching platform and the second X-ray machine switching platform are driven by two first servo motors respectively; the two first servo motors rotate synchronously; The first track is provided with an imaging transfer platform, the imaging transfer platform is provided with an imaging plate, and the imaging plate is 180° away from the ray machine; the imaging transfer platform is driven by a second servo motor; the second servo motor rotates synchronously with the first servo motor; The imaging system is used to reconstruct a three-dimensional radiographic image of the internal structure of the gas-insulated electrical equipment in service according to the scanning trajectory of the radiographic machine and based on the multi-angle radiographic images received on the imaging plate, so as to achieve three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

2. The three-dimensional imaging measurement device for the internal structure of gas-insulated electrical equipment in service according to claim 1, characterized in that: The supporting gantry specifically comprises: a threaded support column and a supporting gantry screw rod; The threaded support column and the supporting gantry screw rod are arranged in parallel in the vertical direction; A lead screw supporting the gantry on one side is connected to the first rail and the second rail respectively through a sliding bracket, and a lead screw supporting the gantry on the other side is connected to the first rail through a sliding bracket; a third servo motor is provided on the sliding bracket; the third servo motor is used to drive the first rail and the second rail to rise and fall on the lead screw supporting the gantry.

3. The three-dimensional imaging measurement device for the internal structure of gas-insulated electrical equipment in service according to claim 1, characterized in that: The arc of the first track is 360°, and the arc of the second track is 150°.

4. The three-dimensional imaging measurement device for the internal structure of gas-insulated electrical equipment in service according to claim 1, characterized in that: Each time the first servo motor rotates a set angle within a set angle range, the X-ray machine performs X-ray fluoroscopic imaging.

5. The three-dimensional imaging measurement device for the internal structure of a gas-insulated electrical device in service according to claim 4, characterized in that: The radiation voltage range of the radiation machine is 150kV-300kV.

6. The three-dimensional imaging measurement device for the internal structure of a gas-insulated electrical device in service according to claim 4, characterized in that: The setting angle range is 0°-3°.

7. A three-dimensional imaging method for measuring the internal structure of a gas-insulated electrical device in service, characterized in that: The three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service is applied to the three-dimensional ray imaging measurement device for the internal structure of a gas-insulated electrical device in service as described in claims 1 to 6, and the three-dimensional ray imaging measurement method for the internal structure of a gas-insulated electrical device in service comprises: A circular trajectory is set according to the first trajectory and the second trajectory, a connecting line of the range of interest of the circular trajectory is used as a reconstruction range for scanning, and a multi-angle radiation image on the imaging plate is obtained according to the scanning trajectory of the radiation machine; A circular trajectory back-projection function is used to perform three-dimensional reconstruction on the ray image at each angle in the multi-angle ray image, and the fan-shaped reflection imaging data in the ray image at each angle is rearranged into fence-shaped parallel projection data; Performing Hilbert transformation on the parallel projection data to generate transformed parallel projection data; Determine the density probability of the reconstructed unit within the reconstruction range according to all transformed parallel projection data; A final three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment in service is constructed according to the density probability of the reconstructed unit.

8. The method for measuring the internal structure of a gas-insulated electrical device in service by three-dimensional ray imaging according to claim 7, characterized in that: The circular trajectory back projection function for: in, is the scanning trajectory; R is the scanning trajectory radius; define a rotating orthogonal coordinate system with the light source as the origin, and its unit vectors are: is the unit vector of the rotating coordinate system, and the rotating coordinate system is a rotating coordinate system with the ray machine as the origin; S is the distance between the imaging plate and the light source; P(u d , v d ,λ) is the projection angle λ The projection value on the detector is known data. For any point on the trajectory, (u d , v d ) is the projection angle λ Projected coordinates on the detector; λ1 is the first projection angle; λ2 is the second projection angle.

9. The method for measuring the internal structure of a gas-insulated electrical device in service by three-dimensional imaging according to claim 8, characterized in that: use Represents any point on the PI line. If the PI line is on the central plane, the transformed parallel projection data for: in, P′(θ, t, s) is P(θ, t r , s), P(θ, t r , s) represents the projection value under any projection polar coordinates, represents any point on the PI line. The PI line is the line segment between the two ray source points. θ is The angle between the origin of the rotating coordinate system and the y-axis, t is the angle between The distance between the virtual detector and the The projection value in the z-axis direction, is the unit direction of the perpendicular line from the rotated coordinate system to the origin.

10. The method for measuring the internal structure of a gas-insulated electrical device in service by three-dimensional imaging according to claim 9, characterized in that: The density probability of the reconstructed unit within the reconstruction range for: Among them, x′ c Point on the PI segment Another form of expression, x c1 , x c2 are the two endpoints of the PI segment, C is a constant, x c is the coordinate of the midpoint of the chord segment, g(x′ c )for The equivalent form of .

Images