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

Abstract

The application discloses a kind of three-dimensional imaging measurement devices and methods of internal structure of gas insulated electrical equipment under service condition, it is related to high-voltage power grid field, device includes: two support gantry between being equipped with horizontal direction parallel detachable first track and second track;The first track can be disassembled into two parts;The material of first track and second track is aluminum alloy material;Two ends of ray machine are fixed on first ray machine adapter and second ray machine adapter respectively;First track is equipped in imaging adapter, imaging adapter is equipped with imaging plate, the imaging plate is 180 ° apart from the ray machine;Imaging system reconstructs three-dimensional image of internal structure of gas insulated electrical equipment under service condition according to the multi-angle ray image on receiving imaging plate according to scanning track. The application can reduce the volume and weight of device, realize CT flaw detection to gas insulated electrical equipment under actual service condition on site and improve detection effect.

Description

Technical Field

[0001] This application relates to the field of high-voltage power grids, and in particular to a three-dimensional radiographic imaging measurement device and method for the internal structure of gas-insulated electrical equipment in service. Background Technology

[0002] Gas-insulated metal-enclosed transmission lines (GILs) are critical equipment for high-voltage power transmission, and the integrity of their internal structure is essential for the stable operation of power systems. However, traditional GIL inspection methods typically require disassembling the equipment or interrupting the power supply, which not only affects the normal operation of the power system but may also pose safety hazards. Therefore, developing an industrial CT system capable of inspecting the internal structure of GILs in situ while they are energized is of great significance.

[0003] Although X-ray imaging has played a revolutionary role in diagnosis and detection, the images of the interior of a three-dimensional object obtained by X-ray imaging are two-dimensional, with information overlapping in the depth direction. On the one hand, it is impossible to determine specific location information, and on the other hand, it reduces the contrast.

[0004] Existing DR (Digital Radiography) inspection methods capable of 3D imaging are limited by digital X-ray imaging, resulting in poor performance in detecting cracks and pores that are narrow and shallow. While a robot-based 3D X-ray imaging system for gas-insulated switches is large and heavy, and difficult to disassemble, it is not suitable for CT (Critical Inspection) of gas-insulated electrical equipment under actual field service conditions. Summary of the Invention

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

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

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

[0008] The supporting gantry frame includes two, and a first track and a second track are arranged in parallel horizontal direction between the two supporting gantry frames; the first track and the second track are detachable tracks, wherein the first track can be disassembled into two parts; the first track and the second track are made of aluminum alloy.

[0009] The first X-ray machine adapter is located at the bottom of the first track, and the second X-ray machine adapter is located at the bottom of the second track. The two ends of the X-ray machine are respectively fixed to the first X-ray machine adapter and the second X-ray machine adapter. The first X-ray machine adapter and the second X-ray machine adapter are each driven by two first servo motors. The two first servo motors rotate synchronously.

[0010] An imaging transition platform is mounted on the first track, and an imaging plate is mounted on the imaging transition platform. The imaging plate is 180° away from the X-ray machine. The imaging transition 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 X-ray image of the internal structure of gas-insulated electrical equipment in service state according to the scanning trajectory of the X-ray machine and the multi-angle X-ray images received on the imaging plate, so as to realize the three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

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

[0013] The threaded bracket column and the supporting gantry screw are arranged parallel to each other in the vertical direction;

[0014] One side of the gantry support screw is connected to the first track and the second track respectively through a sliding bracket, and the other side of the gantry support screw is connected to the first track through a sliding bracket; a third servo motor is provided on the sliding bracket; the third servo motor is used to drive the first track and the second track to move up and down on the gantry support screw.

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

[0016] Optionally, the X-ray machine performs one X-ray fluoroscopic imaging operation for each rotation of the first servo motor within a set angle range.

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

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

[0019] Secondly, this application also provides a method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment in service condition. This method is applied to the aforementioned three-dimensional radiographic imaging measurement device for the internal structure of gas-insulated electrical equipment in service condition. The method includes:

[0020] A circular trajectory is set according to the first and second tracks, and the reconstruction range is scanned using the connecting line of the range of interest of the circular trajectory. Multi-angle X-ray images on the imaging plate are obtained according to the scanning trajectory of the X-ray machine.

[0021] The circular trajectory back projection function is used to perform three-dimensional reconstruction of the ray images at each angle in the multi-angle ray images, and the fan-shaped reflection imaging data in the ray images at each angle are rearranged into fence-shaped parallel projection data.

[0022] Perform a Hilbert transform on the parallel projection data to generate transformed parallel projection data;

[0023] The density probability of the reconstructed units within the reconstruction range is determined based on all the transformed parallel projection data.

[0024] Based on the density probability of the reconstructed unit, a three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment under service conditions is constructed.

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

[0026]

[0027] in, R represents the scan trajectory; R is the radius of the scan trajectory. P(u) is the unit vector of a rotating coordinate system with the X-ray machine as the origin; S is the distance between the imaging plate and the light source; P(u) is the unit vector of the rotating coordinate system. d ,v d ,λ) is the projection angle λ Projection on the detector, For any point on the trajectory, (u d ,v d ) is the projection angle λ The projected 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. Let θ represent any point on the PI line, which is the line segment between the two ray source points. The angle between the coordinate system and the y-axis, where t is the distance from the origin of the coordinate system to the y- The distance, denoted as the unit direction of the perpendicular line from the coordinate system to the origin, is denoted as . s represents the virtual detector. The projection value along the z-axis.

[0031] Let 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 this virtual detector can be entirely represented by known parameters, achieving data rearrangement. The rearrangement formula is:

[0032]

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

[0034]

[0035] Where, x′ c Point on line segment PI Another form of expression (therefore g(x′) c ) is equivalent to ), x c1 x c2 These are the two endpoints of the PI line segment, where C is a constant and x is a constant. c Let x be the coordinates of the midpoint of the chord segment. c ∈[x c1 x c2 ].

[0036] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a three-dimensional radiographic imaging measurement device for the internal structure of gas-insulated electrical equipment in service condition. By setting two detachable tracks, in order to improve 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 is used as the material for both tracks, thereby achieving a lightweight design and reducing the size and weight of the device; due to the lightweight design of the tracks, it is easier for operators to install, thereby realizing CT flaw detection of gas-insulated electrical equipment under actual service conditions in the field.

[0037] Furthermore, this application also provides a method for three-dimensional X-ray imaging measurement of the internal structure of gas-insulated electrical equipment in service. A circular trajectory is set based on a first track and a second track. The reconstruction range is defined by the connecting line of the region of interest of the circular trajectory. Following the scanning trajectory of the X-ray machine, multi-angle X-ray images are acquired on the imaging plate. The density probability of the reconstructed units within the reconstruction range is determined using methods such as the circular trajectory back-projection function and Hilbert transform, thereby constructing a final three-dimensional X-ray reconstruction image of the internal structure of the gas-insulated electrical equipment in service. This method is not limited by digital X-ray imaging and can reconstruct three-dimensional images within any reconstruction range, improving the detection effect. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service state, viewed from the first angle under working conditions, provided in this application;

[0040] Figure 2 A three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service state under working conditions, viewed from a second angle, provided in this application.

[0041] Figure 3 A three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service state under disassembly state and first angle, provided in this application;

[0042] Figure 4 A three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service state under disassembly state and second angle, provided in this application;

[0043] Figure 5 A flowchart of the three-dimensional radiographic imaging measurement method for the internal structure of gas-insulated electrical equipment in service condition provided in this application;

[0044] Figure 6 This is a top view of the relationship between the virtual detector and the coordinates of P(θ,t,s) along the z-axis.

[0045] Figure 7 This is a top view of the relationship between the virtual detector and the coordinates of P(θ,t,s) along the t-axis.

[0046] Figure 8This is a schematic diagram of a non-central plane projection coordinate system. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] like Figures 1-4 As shown, this 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, an X-ray machine 4, and an imaging system.

[0051] The supporting gantry frame 1 includes two, and a first track 2 and a second track 3 are arranged in parallel horizontally between the two supporting gantry frames 1; the first track 2 has an arc of 360° and the second track 3 has an arc of 150°; the first track 2 and the second track 3 are detachable tracks, wherein the first track 2 can be disassembled into two parts; the first track 2 and the second track 3 are made of aluminum alloy.

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

[0053] An imaging transition platform is mounted on the first track 2. An imaging plate 5 is mounted on the imaging transition platform. The imaging plate 5 is 180° away from the X-ray machine 4. The imaging transition platform is driven by a second servo motor. The second servo motor rotates synchronously with the first servo motor.

[0054] Furthermore, the first X-ray machine adapter, the second X-ray machine adapter, and the imaging plate adapter are fixed by a 180-degree arc. The imaging plate adapter is equipped with a second servo motor, which rotates synchronously with the two first servo motors on either the first or second X-ray adapter.

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

[0056] This application uses a lightweight, high-strength aluminum alloy track, and the overall equipment is small in size and detachable, allowing for on-site disassembly and installation by 2-3 people.

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

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

[0059] One side of the gantry frame 1 is connected to the first track 2 and the second track 3 via a sliding bracket 8, and the other side of the gantry frame 1 is connected to the first track 2 via a sliding bracket 8. A third servo motor is provided on the sliding bracket 8. The third servo motor is used to drive the first track 2 and the second track 3 to move up and down on the gantry frame 1.

[0060] The three-dimensional radiographic imaging measurement device for the internal structure of gas-insulated electrical equipment under service conditions proposed in this application has the following advantages: Firstly, since the object to be tested (gil pipe) is a long pipe with a large diameter, a complete ring cannot be directly fitted onto the object to be tested. This application can achieve on-site testing without disassembling the object to be tested by splitting it into two parts. Secondly, the reduced weight of the track makes it easier for operators to install.

[0061] To ensure equipment stability and avoid mechanical errors caused by structural vibrations, the thickness and width of the track cannot be too small. Furthermore, the track diameter exceeding 1 meter results in a very heavy track, making on-site operations difficult. Disassembling it in two allows workers to install it even from heights 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 of the supporting gantry frame 1. A third servo motor is set on each of the two supports on the left and right sides of the gantry frame. The third servo motor drives the first track 2 and the second track to lift and lower.

[0063] The supporting gantry 1 on both sides provides support and maintains the stability of this application; by setting the threaded bracket column 6, the height of the supporting gantry 1 can be adjusted by turning the screw according to the site conditions, and then the supporting gantry 1 can be fixed.

[0064] In practical applications, the X-ray machine 4 performs one X-ray imaging operation every time the first servo motor rotates a set angle within a set angle range.

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

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

[0067] Example 2

[0068] like Figure 5 As shown, this application also provides a method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment in service condition. This method is applied to the aforementioned three-dimensional radiographic imaging measurement device for the internal structure of gas-insulated electrical equipment in service condition. The method includes:

[0069] Step 501: Set a circular trajectory based on the first and second tracks, and scan the area of ​​interest of the circular trajectory as the reconstruction range. According to the scanning trajectory of the X-ray machine, obtain multi-angle X-ray images on the imaging plate.

[0070] Step 502: Use the circular trajectory back projection function to perform three-dimensional reconstruction of 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, The scan trajectory is defined by T, where T represents the transpose operation and R is the radius of the scan trajectory. P(u) is the unit vector of a rotating coordinate system with the X-ray machine as the origin; S is the distance between the imaging plate and the light source; P(u) is the unit vector of the rotating coordinate system.d ,v d ,λ) is the projection angle λ Projection on the detector, For any point on the trajectory, (u d ,v d ) is the projection angle λ The projected 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 a Hilbert transform on the parallel projection data to generate transformed parallel projection data.

[0075] In practical applications, the geometric relationships of circular trajectory cone-beam scanning are first introduced: β and R represent the rotation angle and the distance from the light source to the rotation axis, respectively. To facilitate the description of the rearrangement formula, a virtual detector parallel to the real detector is introduced at the origin of the coordinate axes. Let P1(β, m, n) represent the data on the virtual detector, and (m, n) represent the coordinates on the virtual detector. To describe the rearranged parallel projection data, another virtual detector is introduced, and its projection is denoted by P(θ, t, s), where... Let θ represent any point on the PI line, where the PI line is the line segment between the two ray source points. The angle between the coordinate system and the y-axis, where t is the distance from the origin of the coordinate system to the y- The distance, denoted as the unit direction of the perpendicular line from the coordinate system to the origin, is denoted as . s represents the virtual detector. The projection values ​​along the z-axis are related as follows: Figures 6-7 As shown.

[0076]

[0077]

[0078] Therefore, P1(β, m, n) can be rearranged into parallel data P(θ, t, s), and the rearrangement formula is as follows:

[0079]

[0080] The transformed parallel projection data for:

[0081]

[0082] in,

[0083] use The density function of the reconstructed object has the following relationship:

[0084]

[0085] in express The Hippel transform.

[0086] For any projection P(θ,t,s) (S≠0), regarding A small range of rotation δθ of the axis and about A rotation δθ′ of the axis is equivalent, as they each correspond to a similar arc length, therefore:

[0087]

[0088] Their coordinate system relationship is as follows Figure 8 As shown, the axis of rotation is Axis, Vector Parallel to the central plane, vector Regarding the tilt of the z-axis, and there is P and S represent a projection and a light source, respectively. We have:

[0089]

[0090] in,

[0091] Step 504: Determine the density probability of the reconstructed units within the reconstruction range based on all transformed parallel projection data.

[0092] In practical applications, for the back projection values ​​of all points on the obtained PI line segment, a finite Hibernate inverse transformation is performed to obtain the density probability of the reconstructed cells within the reconstruction range. for:

[0093]

[0094] Where, x′ c Point on line segment PI Another form of expression (therefore g(x′) c ) is equivalent to ), x c1 x c2 These are the two endpoints of the PI line segment, where C is a constant and x is a constant. c Let x be the coordinates of the midpoint of the chord segment. c ∈[x c1 x c2 ]; C is a constant.

[0095] Step 505: Construct a three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment under service conditions based on the density probability of the reconstructed unit; the three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment under service conditions is used to realize the three-dimensional measurement of the internal structure of the gas-insulated electrical equipment.

[0096] Based on the three-dimensional radiographic imaging measurement method for the internal structure of gas-insulated electrical equipment in service condition described in this application, reconstruction is performed based on a line segment connecting positions from 0° to 150° on the scanning trajectory. In this example, the line connecting the range of interest is the 0°-120° line. The reconstruction method is as follows:

[0097] Step 1: Set the circular trajectory based on the rotating track, with the 0°-120° connecting line as the reconstruction range, using the circular trajectory back projection function. Reconstruct the image within a certain angle.

[0098] The circular trajectory in this application is the scanning trajectory, which refers to the trajectory of the X-ray source of the X-ray machine 4 during the scanning process. The X-ray source rotates at a certain angle and continuously images on the imaging plate 5. The imaging plate 5 records the scanning process of the X-ray 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.

[0099] Step 2: Rearrange the fan-shaped reflection imaging data in the ray image at each angle into fence-like parallel projection data, and perform Hilbert transform on the parallel projection data.

[0100] Step 3: By scanning point by point and summing all the transformed parallel projection data, we can obtain:

[0101]

[0102] in, Let θ represent any point on the PI line, where the PI line is the line segment between the two ray source points. The angle between the coordinate system and the y-axis, where t is the distance from the origin of the coordinate system to the y- The distance, denoted as the unit direction of the perpendicular line from the coordinate system to the origin, is denoted as . s represents the virtual detector. The projection value along the z-axis. See the non-center plane projection coordinate system. Figure 8 The axis of rotation is Axis, Vector Parallel to the central plane, vector Regarding the tilt of the z-axis, and there is

[0103] for The coordinate axes obtained after rotation; The coordinate axes are from the light source to the projection point.

[0104] Step 4: Use The density function of the reconstructed element. We can obtain:

[0105]

[0106] 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. The deviation between the three-dimensional graphic and the imaging structure of the object to be detected is measured along the circumference and axis. This application can accurately image the structure outside the area and reconstruct it using the designed three-dimensional graphic.

[0107] This application is lightweight and easy to disassemble and assemble. It can be assembled on-site to achieve in-situ live electrical detection and in-situ live electrical CT imaging.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0109] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service, characterized in that, include: Supporting the gantry frame, first track, second track, first X-ray machine adapter, second X-ray machine adapter, X-ray machine, and imaging system; The supporting gantry includes two, and the first track and the second track are arranged in parallel in the horizontal direction between the two supporting gantry. The first track and the second track are detachable tracks, wherein the first track can be disassembled into two parts; the first track and the second track are made of aluminum alloy. The first X-ray machine adapter is located at the bottom of the first track, and the second X-ray machine adapter is located at the bottom of the second track. The two ends of the X-ray machine are respectively fixed to the first X-ray machine adapter and the second X-ray machine adapter. The first X-ray machine adapter and the second X-ray machine adapter are each driven by two first servo motors. The two first servo motors rotate synchronously. An imaging transition platform is mounted on the first track, and an imaging plate is mounted on the imaging transition platform. The imaging plate is 180° away from the X-ray machine. The imaging transition 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 X-ray image of the internal structure of gas-insulated electrical equipment in service condition based on the scanning trajectory of the X-ray machine and the multi-angle X-ray images received on the imaging plate, so as to realize the three-dimensional measurement of the internal structure of the gas-insulated electrical equipment, specifically including: A circular trajectory is set according to the first and second tracks, and the reconstruction range is scanned using the connecting line of the range of interest of the circular trajectory. Multi-angle X-ray images on the imaging plate are obtained according to the scanning trajectory of the X-ray machine. A circular trajectory back-projection function is used to perform 3D reconstruction of the ray images at each angle in the multi-angle ray images, rearranging the fan-shaped reflection imaging data in the ray images at each angle into fence-like parallel projection data; the circular trajectory back-projection function for: ； in, For the scanning trajectory; R The radius of the scan trajectory; The unit vector of the rotating coordinate system is a rotating coordinate system with the X-ray machine as the origin; S The distance between the imaging plate and the light source; To be at the projection angle λ Down The projection value on the detector is known data. = (x, y, z) is any point on the trajectory, ( () represents the projection angle λ Down Projected coordinates on the detector; A= ; λ 1 The first projection angle; λ 2 This is the second projection angle; Perform a Hilbert transform on the parallel projection data to generate transformed parallel projection data; The density probability of the reconstructed cells within the reconstruction range is determined based on all transformed parallel projection data; the density probability of the reconstructed cells within the reconstruction range for: ； in, Point on line segment PI Another manifestation of ' , Let be the two endpoints of the PI line segment, and C be a constant. Let the coordinates be the midpoint of the chord segment. for The equivalent form; Based on the density probability of the reconstructed unit, a three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment under service conditions is constructed.

2. The three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service condition according to claim 1, characterized in that, The supporting gantry frame specifically includes: a threaded bracket column and a supporting gantry frame screw rod; The threaded bracket column and the supporting gantry screw are arranged parallel to each other in the vertical direction; One side of the gantry support screw is connected to the first track and the second track respectively through a sliding bracket, and the other side of the gantry support screw is connected to the first track through a sliding bracket; a third servo motor is provided on the sliding bracket; the third servo motor is used to drive the first track and the second track to move up and down on the gantry support screw.

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

4. The three-dimensional X-ray imaging measurement device for the internal structure of gas-insulated electrical equipment in service condition 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 one X-ray fluoroscopic imaging.

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

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

7. A method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment in service, characterized in that, The method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment under service conditions is applied to the three-dimensional radiographic imaging measurement device for the internal structure of gas-insulated electrical equipment under service conditions as described in any one of claims 1-6. The method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment under service conditions includes: A circular trajectory is set according to the first and second tracks, and the reconstruction range is scanned using the connecting line of the range of interest of the circular trajectory. Multi-angle X-ray images on the imaging plate are obtained according to the scanning trajectory of the X-ray machine. A circular trajectory back-projection function is used to perform 3D reconstruction of the ray images at each angle in the multi-angle ray images, rearranging the fan-shaped reflection imaging data in the ray images at each angle into fence-like parallel projection data; the circular trajectory back-projection function for: ； in, For the scanning trajectory; R The radius of the scan trajectory; The unit vector of the rotating coordinate system is a rotating coordinate system with the X-ray machine as the origin; S The distance between the imaging plate and the light source; To be at the projection angle λ Down The projection value on the detector is known data. = (x, y, z) is any point on the trajectory, ( () represents the projection angle λ Down Projected coordinates on the detector; A= ; λ 1 The first projection angle; λ 2 This is the second projection angle; Perform a Hilbert transform on the parallel projection data to generate transformed parallel projection data; The density probability of the reconstructed cells within the reconstruction range is determined based on all transformed parallel projection data; the density probability of the reconstructed cells within the reconstruction range for: ； in, Point on line segment PI Another manifestation of ' , Let be the two endpoints of the PI line segment, and C be a constant. Let the coordinates be the midpoint of the chord segment. for The equivalent form; Based on the density probability of the reconstructed unit, a three-dimensional ray reconstruction image of the internal structure of the gas-insulated electrical equipment under service conditions is constructed.

8. The method for three-dimensional radiographic imaging measurement of the internal structure of gas-insulated electrical equipment in service condition according to claim 7, characterized in that, use This represents any point on the PI line. If the PI line lies in the central plane, the transformed parallel projection data... for: ； in, ; for The partial derivative, Represents the projection value in any projected polar coordinate system. Let represent any point on the PI line, where the PI line is the line segment between the two ray source points. for The angle with the y-axis, From the origin of the rotating coordinate system to distance, For virtual detectors The projection value along the z-axis. The unit direction is the perpendicular line from the origin to the rotating coordinate system.

Images