A phased array probe for ultrasonic testing of pot-type insulators and a detection method thereof

Abstract

The present invention relates to a phased array probe and a detection method for ultrasonic detection of pot-type insulators, and relates to the technical field of power transmission and transformation insulation equipment. The dual-size array element ultrasonic phased array probe comprises a large array element, a small array element, a shell, a sleeve, a backing, a metal coating, a matching layer, a screw, and a boss, wherein the large array element and the small array element are arranged alternately, the large array element uses a material with high transmission sensitivity, and the small array element uses a material with high reception sensitivity. The detection depth of the ultrasonic phased array probe is improved by transmitting sound waves by the large array element and receiving sound waves by the small array element; the matching ultrasonic detection method divides the GIS pot-type insulator into a column area and a truncated cone area, including matching column area wedges, truncated cone area wedges, and ultrasonic phased array probe focusing and detection methods. The detection and imaging of internal defects of large-size insulators are achieved by using a dual-size array element ultrasonic phased array probe and a matching ultrasonic detection method.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission and transformation insulation equipment, and in particular to a phased array probe for ultrasonically detecting a pot-type insulator and a detection method thereof. Background Art

[0002] The pot insulator is an important component in the gas insulated switchgear (GIS). It is mainly used for electrical insulation, isolation of adjacent gas chambers, and support of conductors. As one of the weakest links, the performance of the insulator determines the normal operation of the GIS. At present, most insulators in GIS are cast with epoxy resin. Due to processing problems, improper transportation and installation, and even mechanical vibration during operation, cracks or bubbles may appear in the insulator, forming air gap defects in the insulator. These defects eventually lead to equipment insulation breakdown, which causes equipment failure and may cause huge losses. Therefore, it is of great significance to confirm whether there are bubbles and cracks inside the epoxy resin of the pot insulator as soon as possible to ensure the safe operation of the power system.

[0003] At present, the main non-destructive detection methods for internal defects of GIS pot-type insulators are X-ray imaging technology and ultrasonic detection technology. Ultrasonic detection technology has attracted more and more attention in the field of internal defect detection of GIS insulation parts due to its advantages such as low cost, easy portability, high reliability and non-destructive detection. However, pot-type insulators are composite materials composed of epoxy resin and Al2O3 particles, which have high acoustic attenuation. Some of the larger Al2O3 particles or agglomerates of small particles will reflect and refract the detection sound waves, causing scattering attenuation, and produce a fan-shaped detection blind area behind the particles along the direction of sound wave transmission. These factors make it difficult for conventional ultrasonic testing to detect defects deep inside the insulator. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that conventional ultrasonic detection probes cannot detect defects deep inside large-sized insulators.

[0005] In order to solve the above technical problems, the present invention provides a phased array probe for ultrasonic detection of pot-type insulators, comprising: a shell, which is arranged on the outer layer of the detection probe; a sleeve, which is arranged on the inner wall of the shell; a backing, which is arranged inside the sleeve, and one end of the backing is in contact with the inner wall of the shell, and the other end surface of the backing away from the shell is provided with a metal coating layer 1; a metal coating layer 2, a plurality of small array elements and a plurality of large array elements are arranged between the metal coating layer 2 and the metal coating layer 1, and the large array elements and the small array elements are arranged alternately, the metal coating layer 2 is bonded to the plurality of small array elements and the plurality of large array elements, the large array elements have high transmission sensitivity for transmitting sound waves, and the small array elements have high receiving sensitivity for receiving sound waves; a matching layer, which is arranged on the end surface of the metal coating layer 2 away from the metal coating layer 1.

[0006] In one embodiment of the present invention, the detection probe also includes a truncated cone wedge, which is connected to the outer shell, and the end face of the truncated cone wedge is in contact with the GIS pot-type insulator of the detected part, and the end face of the truncated cone wedge in contact with the GIS pot-type insulator of the detected part is a conical surface.

[0007] In one embodiment of the present invention, the detection probe also includes a column area wedge, the column area wedge is connected to the shell, the end face of the column area wedge is in contact with the GIS pot-type insulator of the detected part, and the end face of the column area wedge in contact with the GIS pot-type insulator of the detected part is a cylindrical arc surface.

[0008] In one embodiment of the present invention, four bosses are provided on the outer wall of the shell, bolts are provided on the bosses, and the bosses are connected to the wedge block in the truncated cone area and the wedge block in the column area through the bolts.

[0009] In one embodiment of the present invention, the shell is a hollow shell with one end open and the other end closed, and the closed end of the shell is provided with a wire outlet hole.

[0010] In one embodiment of the present invention, the detection probe further comprises a cable, and the cable passes through the outlet hole and the backing and the metal coating and is welded.

[0011] In one embodiment of the present invention, screws are provided on the outer shell, and the outer shell is connected to the backing through the screws.

[0012] In one embodiment of the present invention, the small array element and the large array element are both piezoelectric chips. The small array element material is a PZT / silicone 1-3 type piezoelectric composite material with a ceramic volume content of 20%, and a piezoelectric voltage coefficient g 33 400*10 -3 V*m / N, with high receiving sensitivity; the large array element material is a PZT / epoxy resin 1-3 type piezoelectric composite material with a ceramic volume content of 50%, and the piezoelectric strain coefficient d 33 It is 550pC / N, with high emission sensitivity.

[0013] In one embodiment of the present invention, the material of the truncated cone area wedge and the column area wedge is cross-linked polystyrene.

[0014] The present invention also provides a detection method of a phased array probe for ultrasonic detection of pot-type insulators, wherein the phased array probe used is the phased array probe for ultrasonic detection of pot-type insulators, and the method comprises the following steps:

[0015] S1. First, divide the GIS pot insulator under test into a conical frustum area and a cylindrical area;

[0016] S2. Bolt the detection probe and the truncated cone wedge together, apply coupling agent on the outer surface of the conical truncated cone of the GIS pot-type insulator to be tested, emit sound waves by several large array elements, and receive reflected sound waves by several small array elements. The focusing line is the axis of the cone. Slowly move the detection probe up and down along the busbar of the conical truncated cone for testing. Move the probe and repeat the above steps until the conical truncated cone is fully covered, thus completing the full coverage scanning and defect detection of the conical truncated cone of the GIS pot-type insulator to be tested.

[0017] S3. Connect the detection probe and the column wedge block with bolts, apply coupling agent on the outer surface of the cylindrical area of ​​the GIS pot-type insulator to be tested, and use several large array elements to emit focused sound waves, and several small array elements to receive reflected sound waves. The focusing depth is the radius of the GIS pot-type insulator to be tested. The scanning method is line scanning. Slowly rotate the detection probe 360° around the axis of the GIS pot-type insulator to be tested, and complete the full coverage scan and defect detection of the cylindrical area of ​​the GIS pot-type insulator to be tested.

[0018] The detection method of the phased array probe for ultrasonic detection of pot-type insulators of the present invention uses the phased array probe for ultrasonic detection of pot-type insulators to detect the column area and the frustum area of ​​the GIS pot-type insulator respectively, so as to realize the detection and imaging of internal defects of large-sized insulators.

[0019] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0020] The phased array probe for ultrasonic detection of basin-type insulators and the detection method thereof described in the present invention significantly reduce the detection blind area by adopting a dual-size array element ultrasonic phased array probe; the large array element with high transmission sensitivity transmits ultrasonic focusing and the small array element with high receiving sensitivity receives ultrasonic waves, thereby improving the amplitude and energy of the sound waves emitted by the ultrasonic phased array probe, thereby increasing the propagation distance of the sound waves in the detected material and increasing the detection depth; the present invention divides the GIS basin-type insulator into a truncated cone area and a cylindrical area, and sets different focusing laws and detection methods for the two areas, thereby realizing full coverage scanning and defect detection of the basin-type insulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0022] Figure 1 This is a schematic diagram of the blind area detected by a common ultrasonic probe;

[0023] Figure 2 This is a schematic diagram of the ultrasonic phased array probe detection blind area;

[0024] Figure 3It is a schematic diagram of the structure of a phased array probe for ultrasonic testing of pot-type insulators in a preferred embodiment of the present invention;

[0025] Figure 4 It is a front view of a GIS pot-type insulator to be tested in a preferred embodiment of the present invention;

[0026] Figure 5 It is a top view of a GIS pot-type insulator to be tested in a preferred embodiment of the present invention;

[0027] Figure 6 It is a front view of the truncated cone wedge in the preferred embodiment of the present invention;

[0028] Figure 7 A side view of a truncated cone wedge in a preferred embodiment of the present invention;

[0029] Figure 8 It is a front view of the wedge block in the column area in the preferred embodiment of the present invention;

[0030] Fig. 9 It is a regional division diagram of the GIS pot-type insulator to be tested in the preferred embodiment of the present invention;

[0031] Fig.10 Schematic diagram of phased array probe detection of ultrasonic testing of pot-type insulators in a preferred embodiment of the present invention Figure 1 ;

[0032] Fig.11 Schematic diagram of phased array probe detection of ultrasonic testing of pot-type insulators in a preferred embodiment of the present invention Figure 2 .

[0033] Explanation of the reference numerals in the specification: housing 1, sleeve 2, backing 3, metal coating 1 4, metal coating 2 5, small array element 6, large array element 7, matching layer 8, boss 10, bolt 11, wire outlet hole 12, cable 13, screw 14, detection probe 100, column area wedge 200, cone area wedge 300. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0035] like Figure 1 The figure shows an ordinary probe. The sound beam emission and propagation path of an ordinary probe is single. When testing GIS pot-type insulators, the sound beam will be reflected by the Al2O3 particles or agglomerates of small particles in the insulator, and a fan-shaped blind area will be formed behind the particles. Defects in the blind area cannot be detected. Figure 2It is an ultrasonic phased array probe, which has 64 array elements and 64 sound beam emission and propagation directions. The overlap of these sound beam paths greatly reduces the blind area range, making the blind area close to zero, and thus detects defects that ordinary probes cannot detect. Conventional ultrasonic phased array probes have piezoelectric chip array elements of the same size, low excitation voltage, and low energy of the emitted sound beam. When detecting high sound attenuation materials such as GIS pot insulators, the sound beam propagation range is limited and the detection depth is low.

[0036] Reference Figure 3 As shown, the phased array probe for ultrasonic detection of pot-type insulators of the present invention includes: a shell 1, which is arranged on the outer layer of the detection probe; a sleeve 2, which is arranged on the inner wall of the shell 1; a backing 3, which is arranged inside the sleeve 2, and one end of the backing 3 is in contact with the inner wall of the shell 1, and the other end surface of the backing 3 away from the shell 1 is provided with a metal coating 1 4; a metal coating 2 5, a plurality of small array elements 6 and a plurality of large array elements 7 are provided between the metal coating 1 4 and the metal coating 1 4, the metal coating 2 5 is bonded to the plurality of small array elements 6 and the plurality of large array elements 7, the large array elements 7 are used to emit sound waves, the small array elements 6 are used to receive sound waves, and the large array elements 7 increase the emission voltage and the energy of the emitted sound beam, thereby increasing the detection depth; a matching layer 8, which is arranged on the end surface of the metal coating 2 5 away from the metal coating 1 4.

[0037] In the above structure, the base of the shell 1 is a rectangular parallelepiped, and the upper surface of the shell 1 is provided with two countersunk holes for installing screws 14, and the shell 1 is connected to the backing 3 through the screws 14. The outer wall of the sleeve 2 is tightly matched with the inner wall of the shell 1, and the inner wall of the sleeve 2 is tightly matched with the backing 3.

[0038] In the above structure, the upper surface of the backing 3 has a threaded hole, which is connected to the housing 1 by screws 14. The material of the backing 3 is composed of lutetium trioxide, aluminum oxide, composite material tungsten powder and epoxy adhesive, and has high sound attenuation and high thermal conductivity. It is used to absorb the sound waves emitted by the chip to the back, thereby reducing the interference of clutter.

[0039] In the above structure, the thickness of the matching layer 8 is 7.2 mm, which is a quarter wavelength, and can allow the acoustic energy to penetrate well, thereby improving the detection sensitivity.

[0040] Preferably, the small array element is a piezoelectric chip, and the material of the piezoelectric chip constituting the small array element is a 1-3 composite material composed of PZT and silica gel, the volume of PZT accounts for 20% of the volume of the 1-3 composite material, and the piezoelectric voltage coefficient g 33 400*10 -3V*m / N, with high receiving sensitivity, a total of 32 small array elements, and a resonant frequency of 1MHz. The large array element is a piezoelectric chip, and the material of the piezoelectric chip of the large array element is a 1-3 composite material composed of PZT (piezoelectric ceramic) and epoxy resin. The volume of PZT accounts for 50% of the volume of the 1-3 composite material, and the piezoelectric strain coefficient d 33 It is 550pC / N, has high transmission sensitivity, has a total of 32 large array elements, a resonant frequency of 1MHz, and a cross-sectional area twice that of small array elements.

[0041] Reference Figure 6-8 As shown, the detection probe 100 also includes a truncated cone area wedge 300, which is connected to the housing 1, and the end face of the truncated cone area wedge 300 contacts the GIS pot-type insulator to be detected, and the end face of the truncated cone area wedge 300 in contact with the GIS pot-type insulator to be detected is a conical surface, and the conical surface matches the shape of the truncated cone area of ​​the GIS pot-type insulator to be detected. The detection probe 100 also includes a column area wedge 200, which is connected to the housing 1, and the end face of the column area wedge 200 contacts the GIS pot-type insulator to be detected, and the end face of the column area wedge 200 in contact with the GIS pot-type insulator to be detected is a cylindrical arc surface. The curvature of the cylindrical arc surface is the same as the curvature of the column area of ​​the GIS pot-type insulator to be detected.

[0042] The material of the truncated cone wedge 300 and the column wedge 200 is cross-linked polystyrene. Cross-linked polystyrene is a thermosetting resin with more outstanding acoustic performance. Its dielectric constant is 2.5-5.6, the dielectric loss is very small, and the sound speed is 2350m / s, which is close to that of water. The loss of ultrasonic signals in the wedge transmission can be ignored.

[0043] In the above structure, a plurality of bosses 10 are provided on the outer wall of the housing 1, and bolts 11 are provided on the bosses 10, and the bosses 10 are connected to the truncated cone area wedge 300 and the column area wedge 200 through the bolts 11. Preferably, the front surface and the rear surface of the housing 1 each have two bosses 10, and the bosses 10 are drilled with through holes for installing the bolts 11, and are connected to the truncated cone area wedge 300 and the column area wedge 200 through the bolts 11.

[0044] In the above structure, the housing 1 is a hollow shell with one end open and the other end closed, and the closed end of the housing 1 is provided with a wire outlet hole 12. The detection probe also includes a cable 13, which passes through the wire outlet hole 12 and the backing 3 and is electrically connected to the metal plating layer 4. The cable 13 is welded to the metal plating layer 4 to transmit and receive electrical signals.

[0045] Based on the above structure, refer to Figure 9-11As shown, an embodiment of the present invention further discloses a detection method of a phased array probe for ultrasonically detecting a pot-type insulator, wherein the phased array probe used is the phased array probe for ultrasonically detecting a pot-type insulator, and the method comprises the following steps:

[0046] S1. First, divide the GIS pot insulator under test into a conical frustum area and a cylindrical area;

[0047] S2, the detection probe and the truncated cone wedge 300 are connected and assembled by bolts, and the coupling agent is applied to the outer surface of the conical truncated cone area of ​​the GIS pot-type insulator to be detected, and the sound waves are emitted and focused by a number of large array elements 7, and the reflected sound waves are received by a number of small array elements 6. The focusing line is the axis of the cone, and the detection probe is slowly moved up and down along the busbar of the conical truncated cone area for detection. The probe is moved and the above steps are repeated until the conical truncated cone area is fully covered, and the full coverage scanning and defect detection of the conical truncated cone area of ​​the GIS pot-type insulator to be detected are completed;

[0048] S3. Bolt the detection probe and the column area wedge 200 together, apply coupling agent on the outer surface of the cylindrical area of ​​the GIS pot-type insulator to be detected, and use a number of large array elements 7 to emit focused sound waves, and a number of small array elements 6 to receive reflected sound waves. The focusing depth is the radius of the GIS pot-type insulator to be detected. The scanning method is line scanning. Slowly rotate the detection probe 360° around the axis of the GIS pot-type insulator to be detected to complete full coverage scanning and defect detection of the cylindrical area of ​​the GIS pot-type insulator to be detected.

[0049] Through the above steps S1 to S3, the full coverage scanning and defect detection of GIS pot insulators can be completed.

[0050] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A phased array probe for ultrasonic testing of pot-type insulators, characterized in that: include, A housing, which is arranged on the outer layer of the detection probe; a sleeve disposed on an inner wall of the housing; A backing is arranged inside the sleeve, and one end of the backing contacts the inner wall of the shell, and the other end surface of the backing away from the shell is provided with a metal coating layer; The second metal plating layer has a plurality of small array elements and a plurality of large array elements between it and the first metal plating layer, and the large array elements and the small array elements are arranged alternately. The second metal plating layer is bonded to the plurality of small array elements and the plurality of large array elements, the large array elements are used to emit sound waves, and the small array elements are used to receive sound waves; A matching layer, which is arranged on the end surface of the metal coating layer 2 away from the metal coating layer 1; A truncated cone area wedge block connected to the housing, wherein the end surface of the truncated cone area wedge block contacts the GIS pot-type insulator to be inspected, and the end surface of the truncated cone area wedge block in contact with the GIS pot-type insulator to be inspected is a conical surface; A column area wedge block connected to the housing, wherein the end surface of the column area wedge block contacts the GIS pot-type insulator to be inspected, and the end surface of the column area wedge block in contact with the GIS pot-type insulator to be inspected is a cylindrical arc surface; Four bosses are arranged on the outer wall of the shell, and bolts are arranged on the bosses. The bosses are connected with the wedge blocks in the truncated cone area and the wedge blocks in the column area through the bolts.

2. The phased array probe for ultrasonic testing of pot-type insulators according to claim 1, characterized in that: The shell is a hollow shell with one end open and the other end closed, and a wire outlet hole is arranged at the closed end of the shell.

3. The phased array probe for ultrasonic testing of pot-type insulators according to claim 1, characterized in that: The detection probe also includes a cable, which passes through the outlet hole and the backing and is welded to the metal coating.

4. The phased array probe for ultrasonic testing of pot-type insulators according to claim 3, characterized in that: The shell is provided with screws, and the shell is connected to the backing through the screws.

5. The phased array probe for ultrasonic testing of pot-type insulators according to claim 1, characterized in that: The small array element and the large array element are both piezoelectric chips.

6. The phased array probe for ultrasonic testing of pot-type insulators according to claim 1, characterized in that: The material of the truncated cone area wedge and the column area wedge is cross-linked polystyrene.

7. A method for ultrasonically testing a pot-type insulator using a phased array probe, wherein the phased array probe used is the phased array probe for ultrasonically testing a pot-type insulator according to claim 1, characterized in that: The steps include: S1. First, divide the GIS pot insulator under test into a conical frustum area and a cylindrical area; S2. Bolt the detection probe and the truncated cone wedge together, apply coupling agent on the outer surface of the conical truncated cone of the GIS pot-type insulator to be tested, emit sound waves by several large array elements, and receive reflected sound waves by several small array elements. The focusing line is the axis of the cone. Move the detection probe up and down along the busbar of the conical truncated cone for testing, change the position of the probe, and repeat the above steps until the conical truncated cone is fully covered, thus completing the full coverage scanning and defect detection of the conical truncated cone of the GIS pot-type insulator to be tested; S3. Connect the detection probe and the column wedge block with bolts, apply coupling agent on the outer surface of the cylindrical area of ​​the GIS pot-type insulator to be tested, and use several large array elements to emit focused sound waves, and several small array elements to receive reflected sound waves. The focusing depth is the radius of the GIS pot-type insulator to be tested. The scanning method is line scanning. Rotate the detection probe 360° around the axis of the GIS pot-type insulator to be tested, and complete the full coverage scan and defect detection of the cylindrical area of ​​the GIS pot-type insulator to be tested.

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