Auxiliary device and method for lossless CT (Computed Tomography) detection of basin-type insulator

Abstract

The invention discloses an auxiliary device and method for nondestructive CT detection of a basin-type insulator, an auxiliary tool comprises short arms, two ends of each short arm are connected with long arms, the top of one end of each short arm is connected with a support block, the top of the other end of each short arm is connected with a vertical support, the number of the long arms and the number of the short arms are two, each long arm is provided with a plurality of blind holes, and the blind holes are communicated with the support block. Blind holes are formed in the two ends of the short arm and used for being connected with the long arm, the long arm and the short arm are fixed through bolts, and a rectangular base support of the auxiliary tool is formed. The auxiliary tool is used for supporting and fixing the basin-type insulator. The auxiliary tool assembles each part of the tool according to the size and the structure of the basin-type insulator; aiming at the structural characteristics of the basin-type insulator, different areas of the basin-type insulator are detected in stages by adopting different scanning modes, different detectors and different placement modes, so that the quality of an industrial CT detection map is enhanced, and the detection capability on internal micro defects of the basin-type insulator is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of power engineering and nondestructive testing, and in particular to an auxiliary device and method for nondestructive CT testing of pot-type insulators. Background Art

[0002] High voltage gas insulated metal enclosed equipment is widely used in power grids due to its advantages over traditional power equipment in terms of floor space, environmental impact, safety, reliability and maintenance workload. It is also one of the main equipment in modern substations. Basin insulators are the most widely used insulating components in gas insulated metal enclosed equipment. Their main function is to insulate and support the central conductor. They must withstand high electric field strength and mechanical loads for a long time when the equipment is running. When there are micro defects such as cracks and bubbles inside them, the defects will distort the electric field and produce stress concentration. The deterioration will spread until the equipment suffers electrical breakdown or cracking and leakage, causing power outages and affecting the safe and stable operation of the power grid.

[0003] At present, conventional factory inspection methods are not effective enough in detecting micro defects inside pot-type insulators. Especially for high-voltage and large-sized pot-type insulators, due to factors such as the dispersion of insulation material quality and the difficulty of process control, the possibility of internal micro defects and performance weaknesses is greatly increased. In addition, due to its relatively complex structure and the lack of differentiated detection and diagnosis methods, the risk of gas-insulated metal-enclosed equipment operating with micro defects has increased significantly. In recent years, the industry has begun to explore the use of low-energy industrial CT to carry out micro-defect detection of pot-type insulators. However, due to the structural characteristics of the pot-type insulators themselves, no matter how they are placed, there are always some angles where X-rays cannot effectively penetrate the pot-type insulators during the rotational scanning process, resulting in low quality of the final image and inaccurate detection results. Especially for high-voltage and large-sized pot-type insulators, this problem is more significant, resulting in the inability to effectively use low-energy industrial CT to detect micro defects inside pot-type insulators.

[0005] For example, my country's invention patent application number 202111042730.9, "An industrial CT inspection method and inspection auxiliary tooling for large and complex aluminum precision castings," proposes an industrial CT inspection method and inspection auxiliary tooling for large and complex aluminum precision castings. It only describes simple inspection steps, and does not specify the scanning method, detector type, and specific inspection process parameters. The inspection method and inspection tooling cannot be applied to the industrial CT inspection of basin-type insulators for gas-insulated metal-enclosed equipment. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides an auxiliary device and method for non-destructive CT detection of pot-type insulators, which is used to solve the problem that X-rays cannot completely penetrate the pot-type insulators due to their own size and structure, making it impossible to carry out full-area industrial CT detection on the pot-type insulators.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an auxiliary device for non-destructive CT detection of pot-type insulators, the auxiliary tooling comprising a short arm, both ends of the short arm are connected to long arms, the top of the long arm at one end of the short arm is connected to a support block, and the top of the long arm at the other end of the short arm is connected to a vertical bracket, and the auxiliary tooling is used to support and fix the pot-type insulator.

[0008] Preferably, there are two long arms and short arms, a plurality of blind holes are opened on the long arm, and blind holes are opened at both ends of the short arm for connecting the long arms. The long arm and the short arm are fixed by bolts to form a rectangular base bracket of the auxiliary tooling.

[0009] Preferably, a plurality of blind holes are formed on the support block, and the support block is fixed to the rectangular base bracket of the spliced ​​auxiliary tooling by bolts, and the support block can be installed by stacking the bolts.

[0010] Preferably, a nondestructive CT detection method for pot-type insulators comprises the following steps:

[0011] The full-area industrial CT inspection of pot-type insulators is carried out in two stages. The first stage inspects the pot-type insulator pot body and its bonding surface with the central metal conductor insert; the second stage inspects the pot-type insulator flange and sealing groove. The scanning method and detector used in each stage are different.

[0012] Preferably, the first stage detection object is the basin body of the basin-type insulator and the bonding surface between the basin-type insulator and the central metal conductor insert, and the detection steps are as follows: the basin-type insulator is placed with the convex surface downward on the turntable of the industrial CT, and the basin-type insulator placed on the turntable of the CT is scanned by an X-ray source, the scanning mode is fan beam scanning, the detector is a linear array detector, the small focus mode is selected, and the slice thickness is set to between 0.5 times and 1 times the small focus size.

[0013] Preferably, the second stage inspection objects are the pot-type insulator flange and sealing groove, and the auxiliary tooling and pot-type insulator installation steps; the pot-type insulator is fixed in a vertical posture by special auxiliary tooling and placed on the turntable of the industrial CT equipment, and the assembly between different parts of the auxiliary tooling is adjusted according to the shape and size of the pot-type insulator.

[0014] Preferably, the inspection object of the second stage is the flange and sealing groove of the pot insulator, and the inspection steps are: first, the flange and sealing groove area of ​​the pot insulator is evenly divided into several parts. During the inspection, the inspected part of the pot insulator flange is rotated to the top so that its central axis is vertically upward, and the pot insulator flange is divided into several parts by an X-ray source, and the inspection is performed separately. During the inspection, cone beam scanning is selected as the scanning mode, and the detector adopts a planar array detector, a small focus mode is selected, and the number of projections is set to 720 or more; for pot insulators with a voltage level of 220kV and below, the pot insulator flange and sealing groove are evenly divided into 4 parts; for pot insulators with voltage levels of 500kV and 750kV, the pot insulator flange and sealing groove are evenly divided into 6 to 8 parts; for pot insulators with a voltage level of 1000kV, the pot insulator flange and sealing groove are evenly divided into 10 to 12 parts, and the inspection is performed separately.

[0015] Preferably, the step of detecting the circumferential division of the flange and the sealing groove of the pot-type insulator of different voltage levels is specifically as follows:

[0016] For pot insulators with voltage levels of 220kV and below, the pot insulator flange and sealing groove are evenly divided into 4 parts along the circumference; for pot insulators with voltage levels of 500kV and 750kV, the pot insulator flange and sealing groove are evenly divided into 6 to 8 parts along the circumference; for pot insulators with voltage levels of 1000kV, the pot insulator flange and sealing groove are evenly divided into 10 to 12 parts along the circumference, and they are tested separately.

[0017] Compared with the existing technology, the present invention has the following beneficial effects: 1. The present invention detects the pot-type insulator in stages by adopting different scanning methods, different detectors and different placement methods for different areas according to the structural characteristics of the pot-type insulator, and designs special auxiliary tooling for this purpose. The detection range can cover the entire area of ​​the pot-type insulator, ensuring that every part to be detected is completely penetrated by X-rays, thereby obtaining good image quality. In addition, the detection method and special auxiliary tooling provided by the present invention are simple to implement and manufacture, have excellent versatility, and have strong on-site practicality and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the auxiliary tooling of the present invention.

[0019] Figure 2 It is a schematic diagram of the flange and sealing groove detection of the basin-type insulator of the present invention.

[0020] Figure 3 Schematic diagram showing the side inspection of the flange and sealing groove of the basin-type insulator of the present invention

[0021] Figure 4 It is a schematic diagram of detecting the central metal conductor insert of the pot-type insulator of the present invention.

[0022] Figure 5 It is a schematic diagram of the three-dimensional structure of the pot-type insulator of the present invention.

[0023] In the figure: 1. Auxiliary tooling; 11. Long arm; 12. Short arm; 13. Support block; 14. Vertical bracket; 2. Turntable; 3. X-ray source; 4. Linear array detector; 5. Area array detector; 6. Basin insulator; 601. Basin body; 602. Center metal conductor insert; 603. Flange and sealing groove. DETAILED DESCRIPTION

[0024] like Figure 1 As shown, the present invention provides a technical solution: an auxiliary device for non-destructive CT detection of pot-type insulators, the auxiliary tooling 1 includes a short arm 12, both ends of the short arm 12 are connected to long arms 11, a support block 13 is connected to the top of the long arm 11 at one end of the short arm 12, and a vertical bracket 14 is connected to the top of the long arm 11 at the other end of the short arm 12. The auxiliary tooling 1 is used to support and fix the pot-type insulator.

[0025] Furthermore, there are two long arms 11 and short arms 12, the long arm 11 is 600 mm long, and a blind hole is provided at every 100 mm in the long arm 11, the short arm 12 is 300 mm long, and blind holes are provided at both ends of the short arm 12 for connecting with the two long arms 11, and the long arm 11 and the short arm 12 are fixed by bolts to form a rectangular base bracket of the auxiliary tooling 1, and the distance between the long arm 11 and the short arm 12 is adjusted according to the outer diameter of the pot-type insulator 6 supported and fixed.

[0026] Furthermore, a plurality of blind holes are formed on the support block 13, and the support block 13 is fixed to the rectangular base bracket of the assembled auxiliary tooling 1 by bolts. In addition, the support block 13 is stacked according to the shape and size requirements of the bonding surface between the basin body 601 of the basin-type insulator 6 and the central metal conductor insert 602, so as to support and fix the shape of the bonding surface of the central metal conductor insert 602 of the basin-type insulator 6.

[0027] Installation process of the auxiliary tooling 1: first, place the short arm 12 between the two long arms 11, connect the blind holes at both ends of the short arm 12 with the blind holes of the left and right long arms 11 respectively, and use bolts to fix the connected short arm 12 and the two long arms 11. Similarly, place the second short arm 12 between the two long arms 11, away from the other end of the installed short arm 12, and also use bolts to fix the second short arm 12 to the two long arms 11. After the short arm 12 and the long arm 11 are fixed by bolts, connect the blind hole of the support block 13 with the blind hole at the top of the long arm 11, and use bolts to fix the support block 13 and the long arm 11. Then, install the two vertical brackets 14 on the top of the long arm 11 away from the other end of the installed support block 13, and assemble the installed long arm 11, short arm 12, support block 13 and vertical bracket 14 together. Splicing and fixing to form an auxiliary support bracket, and a number of blind holes are provided on the support block 13. The support block 13 is stacked according to the shape and size of the basin body 601 of the basin insulator 6 to achieve convex surface support of the basin insulator 6; according to the shape structure and size of the basin insulator 6 to be detected, the base bracket, the vertical bracket 14 and the stackable support block 13 are assembled into a special auxiliary support bracket, so that the basin insulator 6 can be relatively fixed and rotationally scanned in a stable and vertical posture; and the auxiliary tooling 1 is made of nylon material, and the auxiliary tooling 1 is used to support the basin insulator 6: First, it ensures that there is an obvious density difference between the auxiliary tooling 1 and the various parts of the basin insulator 6, and improves the image quality of the edge part; second, it reduces the influence of the auxiliary tooling 1 on the penetration of X-rays; third, it avoids bumps and scratches during the installation process that may cause damage to the basin insulator 6 itself.

[0028] Furthermore, a non-destructive CT detection method for pot-type insulators comprises the following steps:

[0029] The full-area industrial CT inspection of the pot-type insulator 6 by using the inspection equipment is carried out in two stages. The two stages are: in the first stage, the inspection object is the pot-type insulator 6 pot body 601 and the bonding surface with the central metal conductor insert 602; in the second stage, the inspection object is the pot-type insulator 6 flange and sealing groove 603; the scanning method and detector used in each stage are different; and the inspection equipment includes a turntable 2, an X-ray source 3, a linear array detector 4 and a planar array detector 5, and the inspection object of the pot-type insulator 6 is three parts, namely, the pot body 601, the central metal conductor insert 602 and the flange and sealing groove 603.

[0030] Furthermore, the detection object of the first stage is the basin body 601 of the basin insulator 6 and the bonding surface with the central metal conductor insert 602. The detection steps are as follows: the basin insulator 6 is placed with the convex surface facing downward on the turntable 2 of the industrial CT, and the basin insulator 6 placed on the turntable 2 of the CT is scanned by the X-ray source 3. The scanning mode selects fan beam scanning, and the detector adopts the linear array detector 4, and the small focus mode is selected; the slice thickness is set to 0.25mm. By analyzing the CT scanning detection map of the basin insulator 6 on the turntable 2 by the X-ray source 3, two air gap defects are found in the basin body 601 and the bonding surface with the central metal conductor insert 602. The three-dimensional dimensions are approximately 2.61mm×1.70mm×0.46mm and 1.60mm×1.29mm×0.49mm, respectively. The defect position is basically consistent with the high-precision partial discharge detection positioning position, which verifies the accuracy of the industrial CT detection result.

[0031] Furthermore, the second stage inspection object is the flange and sealing groove 603 of the pot-type insulator 6, and the installation steps of the auxiliary tooling 1 and the pot-type insulator 6; the pot-type insulator 6 is fixed in a vertical posture by the special auxiliary tooling 1 and placed on the turntable 2 of the industrial CT equipment, and the assembly between the different parts of the pot body 601 of the auxiliary tooling 1 is adjusted according to the shape and size of the pot-type insulator 6.

[0032] Further, the detection object of the second stage is the flange and sealing groove 603 of the pot insulator 6, and the detection steps are as follows: first, the flange and sealing groove 603 area of ​​the pot insulator 6 are evenly divided into 8 parts. During the detection, the flange and sealing groove 603 of the pot insulator 6 to be detected are rotated to the top, so that the central axis is vertically upward. During the detection, the scanning mode is cone beam scanning, the detector is a planar array detector 5, the small focus mode is selected, and the number of projections is set to 720; by analyzing the X-ray source 3, each part of the flange and sealing groove 603 of the pot insulator 6 is respectively CT scanned and detected. From the atlas, many micro cracks with a width of 0.3mm to 0.5mm and many areas of uneven density were found near several bolt holes in the flange and sealing groove 603; for pot insulators with a voltage level of 220kV and below, the pot insulator flange and sealing groove were evenly divided into 4 parts; for pot insulators with a voltage level of 500kV and 750kV, the pot insulator flange and sealing groove were evenly divided into 6 to 8 parts; for pot insulators with a voltage level of 1000kV, the pot insulator flange and sealing groove were evenly divided into 10 to 12 parts, and tested separately.

[0033] Furthermore, the steps of detecting the circumferential division of the flange and the sealing groove of the pot-type insulator of different voltage levels are specifically as follows:

[0034] For pot insulators with voltage levels of 220kV and below, the pot insulator flange and sealing groove are evenly divided into 4 parts along the circumference; for pot insulators with voltage levels of 500kV and 750kV, the pot insulator flange and sealing groove are evenly divided into 6 to 8 parts along the circumference; for pot insulators with voltage levels of 1000kV, the pot insulator flange and sealing groove are evenly divided into 10 to 12 parts along the circumference, and they are tested separately.

[0035] The above embodiments demonstrate that the auxiliary device and method for nondestructive CT detection of pot-type insulators proposed by the present invention have obvious effectiveness and strong operability.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A non-destructive CT detection auxiliary device for pot-type insulators, characterized in that: The auxiliary tooling (1) comprises a short arm (12), both ends of the short arm (12) are connected to long arms (11), the top of the long arm (11) at one end of the short arm (12) is connected to a support block (13), and the top of the long arm (11) at the other end of the short arm (12) is connected to a vertical bracket (14). The auxiliary tooling (1) is used to support and fix the pot-type insulator.

2. The non-destructive CT detection auxiliary device for pot-type insulators according to claim 3 is characterized in that: The long arm (11) and the short arm (12) are provided with two in total, a plurality of blind holes are provided on the long arm (11), and blind holes are provided at both ends of the short arm (12) for connecting the long arm (11), and the long arm (11) and the short arm (12) are fixed by bolts to form a rectangular base bracket of the auxiliary tooling (1).

3. The non-destructive CT detection auxiliary device for pot-type insulators according to claim 2 is characterized in that: The support block (13) is provided with a plurality of blind holes, and the support block (13) is fixed to the rectangular base bracket of the spliced ​​auxiliary tooling (1) by bolts, and the support block (13) can be installed by stacking the bolts.

4. A non-destructive CT testing method for pot-type insulators, characterized in that: The steps include: The full-area industrial CT inspection of pot-type insulators is carried out in two stages. The first stage is to inspect the pot-type insulator pot body and its bonding surface with the central metal conductor insert; The second stage of inspection targets the flange and sealing groove of the pot-type insulator; the scanning method and detector used in each stage are different.

5. The nondestructive CT testing method for pot-type insulators according to claim 4, characterized in that: The first stage of inspection targets the pot-type insulator pot body and its bonding surface with the central metal conductor insert. The inspection steps are as follows: place the pot-type insulator convex surface downward on the turntable of the industrial CT, and scan the pot-type insulator placed on the turntable of the CT through an X-ray source. The scanning method uses fan beam scanning, the detector uses a linear array detector, the small focus mode is selected, and the slice thickness is set to between 0.5 and 1 times the small focus size.

6. The nondestructive CT testing method for pot-type insulators according to claim 5, characterized in that: The objects of the second stage inspection are the flange and sealing groove of the pot-type insulator, the auxiliary tooling (1) and the pot-type insulator installation steps; the pot-type insulator is fixed in a vertical posture by the special auxiliary tooling (1) and placed on the turntable of the industrial CT equipment, and the assembly between different parts of the auxiliary tooling (1) is adjusted according to the shape and size of the pot-type insulator.

7. A nondestructive CT testing method for pot-type insulators according to claim 6, characterized in that: The objects of the second stage inspection are the flanges and sealing grooves of pot-type insulators, and the inspection steps are as follows: first, the flange and sealing groove areas of the pot-type insulators are evenly divided into several parts. During the inspection, the inspected part of the pot-type insulator flange is rotated to the top so that its central axis is vertically facing upwards, and the pot-type insulator flange is divided into several parts by an X-ray source, and the parts are inspected separately. During the inspection, cone beam scanning is selected as the scanning mode, the detector uses an array detector, the small focus mode is selected, and the number of projections is set to 720 or more.

8. The nondestructive CT testing method for pot-type insulators according to claim 7, characterized in that: The steps for detecting the circumferential division of the flange and the sealing groove of the pot-type insulator of different voltage levels are specifically as follows: For pot insulators with voltage levels of 220kV and below, the pot insulator flange and sealing groove are evenly divided into 4 parts along the circumference; for pot insulators with voltage levels of 500kV and 750kV, the pot insulator flange and sealing groove are evenly divided into 6 to 8 parts along the circumference; for pot insulators with voltage levels of 1000kV, the pot insulator flange and sealing groove are evenly divided into 10 to 12 parts along the circumference, and they are tested separately.

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