A method for detecting internal defects of a hollow composite insulator

Abstract

The application discloses a kind of internal defect detection methods of hollow composite insulator, the method is first using tool to hollow composite insulator is transverse and keeps level, then using ring as auxiliary tool sets two ultrasonic probes;Make ring and hollow composite insulator keep concentric, push into ring hollow composite insulator hollow inner cavity equipped with ultrasonic probe and continue to push, continue to output ultrasonic detection result in the process of pushing;Then the ring is circumferentially rotated, repeat the above ultrasonic detection step, the multiple ultrasonic detection results of ultrasonic probe in the same group are combined on hollow composite insulator model, obtain two internal defect schematic diagram of hollow composite insulator;Two internal defect schematic diagram is superimposed, that is, the internal defect detection result of hollow composite insulator is obtained.The application can continuously sample and detect the internal defect of hollow composite insulator, its continuity is good, detection cost is low, and sampling result is intuitive.

Description

Technical Field

[0001] This invention relates to structural defect detection technology for composite insulators in the power transmission and transformation industry, specifically to a method for detecting internal defects in hollow composite insulators. Background Technology

[0002] Hollow insulators play two basic roles in overhead transmission lines: supporting the conductors and preventing current from returning to the ground. Currently, insulators used in the power transmission and transformation industry are roughly divided into two categories: composite insulators and pure porcelain insulators. Among them, composite insulators have better structural stability and higher safety under the same structural size conditions compared to pure porcelain insulators.

[0003] Generally, composite insulators typically consist of a core rod, sheds, and connecting fittings at both ends of the core rod. The core rod can be either fiberglass or ceramic. However, both types of core rods may develop internal defects during the molding process due to various reasons. If these internal defects are not eliminated, they will adversely affect the dielectric and mechanical strength of the product during use, causing quality defects such as cracks and air entrapment in the core rod portion of the composite insulator. Without early warning, these cracks will slowly propagate and penetrate, affecting the performance of the composite insulator, and in severe cases, may even lead to… This can lead to structural cracking and failure. Considering that prestress needs to be applied when assembling the connecting hardware at both ends of the composite insulator, the core rod part at both ends of the composite insulator with internal defects is prone to structural strength defects when assembling the connecting hardware, which will have a negative impact on the assembly performance of the composite insulator. Under pre-tightening conditions, it will also cause excessive radial stress on the core rod, leading to brittle failure of the core rod. In severe cases, it will also affect the overall mechanical strength of the composite insulator, causing the connection part to tear and fail during operation because it cannot withstand various pressures, tensions and torques. It will also affect the overall sealing and electrical performance of the composite insulator.

[0004] For the reasons mentioned above, it is necessary to conduct internal defect structure detection on the core rod of hollow composite insulators. However, the existing detection methods only conduct local detection on specific weak locations of the core rod of hollow composite insulators, which has the defects of incomplete interval coverage, slow overall detection speed and low detection accuracy. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a method for detecting internal defects in hollow composite insulators, so as to solve the defects in the above-mentioned technical background.

[0006] The technical problem solved by this invention is achieved by the following technical solution:

[0007] A method for detecting internal defects in hollow composite insulators, specifically including the following steps:

[0008] S1. Place the tooling horizontally on the hollow composite insulator and keep its position fixed so that the hollow inner cavity of the hollow composite insulator remains horizontal.

[0009] S2. Using a ring smaller than the cross-sectional circle of the insulator's inner cavity as an auxiliary tool, two sets of ultrasonic probes are evenly arranged on the ring surface. Each set of ultrasonic probes includes multiple ultrasonic probe units. One set of ultrasonic probes uses a straight probe as an ultrasonic probe unit, and the other set uses an angled probe as an ultrasonic probe unit. The straight probes and angled probes are staggered on the ring surface.

[0010] S3. Keep the ring concentric with the hollow composite insulator and push it into the hollow cavity of the hollow composite insulator. Turn on the two sets of ultrasonic probes and push the ring out of the hollow cavity of the hollow composite insulator along the length of the hollow composite insulator. During this process, continuously collect and record the ultrasonic data of the two sets of ultrasonic probes and simulate the hollow composite insulator model along its length to obtain the corresponding ultrasonic test results.

[0011] S4. Rotate the ring circumferentially, and then repeat step S3 N times, where N is a natural number. The value of N is such that there are no blind spots in the detection of the hollow composite insulator cavity by either of the two sets of ultrasonic probes, so that each of the two sets of ultrasonic probes can detect N ultrasonic test results.

[0012] S5. Combine the N ultrasonic test results of the ultrasonic probes in the same group on the hollow composite insulator model to obtain two schematic diagrams of internal defects of the hollow composite insulator; superimpose the positions of the two schematic diagrams of internal defects to obtain the internal defect test results of the hollow composite insulator.

[0013] As a further limitation, the advancement of the ring within the hollow composite insulator cavity is achieved through the telescopic operation of a telescopic structure integrally connected to the ring.

[0014] As a further limitation, the ring is mounted on a traveling frame, and traveling wheels are symmetrically arranged at the bottom of the traveling frame. The ring is propelled within the cavity of the hollow composite insulator through the traveling frame.

[0015] The running wheel is a solid rubber wheel, and the outer thickness of the running wheel is less than the inner thickness to ensure a good fit with the inner surface of the hollow composite insulator.

[0016] As a further limitation, the data acquisition interval of the ultrasonic probe unit in the two sets of ultrasonic probes is 0.5 to 0.6 seconds, and the traveling speed of the ring in the inner cavity of the hollow composite insulator does not exceed 30 cm / s.

[0017] As a further limitation, the ultrasonic probe used is a high-frequency straight probe with a 115 sequence.

[0018] As a further limitation, the angle probe used in the ultrasonic probe is a low-frequency angle probe with a 115 sequence, and the slope of the angle probe is controlled between K1.8 and K2.2.

[0019] Beneficial effects: The internal defect detection method for hollow composite insulators of the present invention can perform non-destructive testing of internal defects of hollow composite insulators using ultrasonic detection. It is simple and efficient to operate. It can continuously sample internal defects of hollow composite insulators by combining straight probes and angle probes. Then, the sampling results are combined on the model of hollow composite insulators to obtain the internal defect detection results of hollow composite insulators more intuitively. This makes it easier for relevant personnel to understand the internal defects of hollow composite insulators, so as to facilitate early reinforcement and later maintenance. Attached Figure Description

[0020] Figure 1 This is a side view sectional view of the method of the present invention in an implemented state.

[0021] Figure 2 This is a schematic diagram of the end face view of the method of the present invention in an implemented state.

[0022] The components include: 1. Composite insulator core rod; 2. Composite insulator umbrella body; 3. Composite insulator inner cavity; 4. Ring; 5. Traveling wheel; 6. Traveling frame; 7. Counterweight unit; 8. Traveling frame zero-position platform; 9. Ultrasonic angle probe; 10. Ultrasonic straight probe. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention and to make the technical means, creative features, objectives, and effects of the present invention readily understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific illustrations.

[0024] It should be noted that the embodiments in the specification, claims, and accompanying drawings of this invention can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed.

[0025] Furthermore, the embodiments shown in this detailed description are merely one example of the possible embodiments of the present invention and represent all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0026] This embodiment Figure 1 , Figure 2 The demonstration showcases an auxiliary tool for implementing a method for detecting internal defects in hollow composite insulators. This auxiliary tool includes a support base and a detection device.

[0027] In this embodiment, the support base is used to provide lateral support for the hollow composite insulator to be tested and to keep the hollow composite insulator in a horizontal state. The placement and support method of the hollow composite insulator can be any existing insulator support structure. The hollow composite insulator to be tested can be an assembled hollow composite insulator with end-face connection fittings, or a hollow composite insulator without connection fittings but with molded silicone rubber skirts, or something similar. Figure 1 The hollow composite insulator sintered body shown is formed by direct sintering of the blank, having a complete composite insulator core rod 1 and composite insulator umbrella body 2. In this embodiment, the hollow composite insulator sintered body is glazed and formed with silicone rubber umbrella after passing the inspection, which also effectively reduces the waste of glaze and silicone rubber materials.

[0028] A traveling frame zero-position platform 8 is provided on one side of the bearing base corresponding to the placement position of the hollow composite insulator. The traveling frame 6, which serves as the testing equipment, enters the inner cavity 3 of the composite insulator through the traveling frame zero-position platform 8 to perform testing operations, and exits back onto the traveling frame zero-position platform 8 after the testing is completed to complete one testing operation cycle.

[0029] In this embodiment, the bottom of the traveling frame 6, which serves as the testing device, is provided with traveling wheels 5. The traveling wheels 5 are used to axially feed the hollow composite insulator within the cavity 3 of the composite insulator. At one end of the traveling frame 6 away from the zero-position platform 8, a ring 4 is detachably assembled. The ring 4 is a circular ring structure with an outer diameter smaller than the inner diameter of the cavity 3 of the composite insulator. By assembling it at a specific position on the traveling frame 6, the ring 4 is concentrically assembled with the cavity 3 of the composite insulator.

[0030] In this embodiment, to improve the traveling performance of the traveling frame 6 within the composite insulator cavity 3, the four traveling wheels 5 at the bottom of the traveling frame 6 are solid rubber wheels and have the following characteristics: Figure 2The structure shown has an outer thickness of less than the inner thickness of the traveling wheel 5, so that the wheel surface of the traveling wheel 5 can fit against the arc surface of the inner cavity 3 of the composite insulator, thus enabling the traveling wheel 5 to better achieve the purpose of traveling along the axial direction of the hollow composite insulator. In addition, in order to ensure the stability of the ring 4 on the traveling frame 6, a counterweight unit 7 is also provided on the traveling frame 6 at one end relative to the tail of the ring 4.

[0031] Two sets of ultrasonic probes are arranged on the outer ring surface of ring 4. The two sets of ultrasonic probes are the first ultrasonic probe group and the second ultrasonic probe group. The first ultrasonic probe group uses 20 ultrasonic angle probes 9 as ultrasonic probe units. The corresponding ultrasonic angle probes 9 are 115 sequence ultrasonic low frequency angle probes, and the slope of the 20 such angle probes needs to be controlled between K1.8 and K2.2 and kept consistent. The second ultrasonic probe group uses 20 ultrasonic straight probes 10 as ultrasonic probe units. The corresponding ultrasonic straight probes 10 are 115 sequence ultrasonic high frequency straight probes.

[0032] The ultrasonic angle probe 9 and the ultrasonic straight probe 10 are positioned on the outer ring surface of the ring 4 as follows: Figure 2 The ultrasonic angle probe 9 and ultrasonic straight probe 10 are arranged in an equally spaced and staggered pattern. They are turned on and perform detection operations synchronously. The data lines inside are bundled together and connected to the corresponding ultrasonic equipment host.

[0033] Both the ultrasonic angle probe 9 and the ultrasonic straight probe 10 include an ultrasonic transmitter and a differential coil probe. The ultrasonic transmitter emits ultrasonic signals of a certain frequency to the inner wall surface of the hollow composite insulator cavity 3. When in operation, the differential coil probe is in close contact with the inner wall surface of the composite insulator cavity 3 and receives ultrasonic signal feedback signals from both vertical and angled directions. This signal interferes at the defect location of the hollow composite insulator, resulting in a difference signal output. Therefore, signal analysis can determine the defect type of the hollow composite insulator.

[0034] The planar dimensions of the defect location are obtained based on the feedback signal from the ultrasonic straight probe 10;

[0035] The height location information of the defect is obtained based on the feedback signal from the ultrasonic angle probe 9;

[0036] The defect type at the defect location is obtained by comparing the information from the superimposed ultrasonic straight probe 10 and ultrasonic angle probe 9 with similar information in the database.

[0037] In different embodiments, the number and spacing of ultrasonic probe units on the two sets of ultrasonic probes and the size of the ring 4 can be selected according to the actual size of the hollow composite insulator to be tested. Correspondingly, the detachable assembly structure of the ring 4 on the traveling frame 6 can be used to test hollow composite insulators with different sizes of composite insulator cavities 3 by matching the rings 4 of different sizes and the two sets of ultrasonic probes of different styles.

[0038] To ensure the stability and accuracy of the detection data from the ultrasonic probe unit, a signal conversion circuit and a power amplification circuit can be installed between the ultrasonic probe unit and the main unit of the ultrasonic equipment. This circuit converts the relevant ultrasonic signals into readable signals and then amplifies them.

[0039] In another embodiment, the traveling frame 6, which serves as the propulsion structure of the ring 4, can also be replaced by a telescopic structure, such as a top rod, a pull rod, or a telescopic rod. The top rod, pull rod, or telescopic rod is fixedly assembled with the ring 4, and an external force (such as a motor) drives the corresponding top rod, pull rod, or telescopic rod to extend or retract, thereby driving the ring 4 to reciprocate along the axial direction of the hollow composite insulator within the inner cavity 3 of the composite insulator, achieving the same effect.

[0040] The method for detecting internal defects in hollow composite insulators is specifically carried out using the aforementioned equipment in the following sequence:

[0041] First, the hollow composite insulator to be tested is placed and supported using the bearing base, ensuring that the inner cavity 3 of the composite insulator remains horizontal. Then, the traveling frame 6 is assembled with ring 4 at the zero-position platform 8. Before assembling the corresponding ring 4, the ultrasonic angle probe 9 and ultrasonic straight probe 10 are assembled and adjusted.

[0042] The traveling frame 6 with the assembled ring 4 is aligned and calibrated to ensure that the ring is concentric with the hollow composite insulator. Then the traveling frame 6 is positioned as follows: Figure 1 The pattern shown is introduced into the inner cavity 3 of the composite insulator. Two sets of ultrasonic probes are turned on, and the ring 4 is pushed from the right to the left by the traveling frame 6 until the traveling frame 6 pushes the ring 4 out of the inner cavity 3 of the composite insulator from the left, thus completing one round of testing.

[0043] After one round of testing is completed, the traveling frame 6 is moved back to the traveling frame zero-position platform 8. While on the traveling frame zero-position platform 8, the ring 4 and the hollow composite insulator to be tested are rotated relative to each other in a circumferential manner. In different embodiments, the rotation method can be that the ring 4 is rotated on the traveling frame 6 using a swivel, or the hollow composite insulator to be tested can be rotated directly on the bearing base. After rotating a specific angle (usually 3 to 5 degrees), another round of testing is performed until either of the two sets of ultrasonic probes has no blind spots in the detection of the inner cavity of the hollow composite insulator.

[0044] During the testing process, the ultrasonic angle probe 9 and ultrasonic straight probe 10 installed on the ring 4 continuously collect and record ultrasonic data. In order to ensure the continuity and stability of data collection, the data acquisition interval of the ultrasonic probe unit in the two sets of ultrasonic probes is 0.5 to 0.6 seconds, and the traveling speed of the ring 4 in the cavity of the hollow composite insulator is controlled to not exceed 30 cm / s.

[0045] The hollow composite insulator is modeled using software. After each round of testing, the obtained ultrasonic data is projected onto the corresponding hollow composite insulator to obtain the corresponding ultrasonic test results. In N rounds of testing (N being a natural number), each set of ultrasonic probes can obtain N ultrasonic test results. The N ultrasonic test results from the same set of probes are then combined on the same hollow composite insulator model to obtain two schematic diagrams of internal defects in the hollow composite insulator. These two schematic diagrams are then superimposed to obtain the internal defect detection result of the hollow composite insulator.

[0046] The above-mentioned internal defect detection results can be simulated on the model of the hollow composite insulator, thus intuitively showing the location, size, shape and type of defects inside the hollow composite insulator.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting internal defects of a hollow composite insulator, characterized by, The method specifically comprises the following operation steps: S1, placing the hollow composite insulator horizontally on a jig and keeping the position fixed, so that the hollow inner cavity of the hollow composite insulator is kept in a horizontal state; S2, using a ring with a size smaller than the cross-sectional circle size of the inner cavity of the insulator as an auxiliary tool, arranging two groups of ultrasonic probes on the ring surface of the ring respectively, each group of probes being uniformly distributed on the ring surface, each group of ultrasonic probes comprising a plurality of ultrasonic probe units, one group of ultrasonic probes in the two groups of ultrasonic probes adopting straight probes as the ultrasonic probe units, and the other group of ultrasonic probes adopting inclined probes as the ultrasonic probe units, the straight probes and the inclined probes being arranged alternately on the ring surface of the ring; S3, keeping the ring concentric with the hollow composite insulator and pushing the ring into the hollow inner cavity of the hollow composite insulator, turning on the two groups of ultrasonic probes, and pushing the ring out of the hollow inner cavity of the hollow composite insulator along the length direction of the hollow composite insulator, during which the ultrasonic data of the two groups of ultrasonic probes are continuously collected and recorded, and simulation is performed in the length direction of the hollow composite insulator model to obtain corresponding ultrasonic detection results; S4, rotating the ring in the circumferential direction, and then repeating step S3 N times, N being a natural number, the value of N being determined according to the condition that any one group of ultrasonic probes in the two groups of ultrasonic probes does not have a detection blind spot for the inner cavity of the hollow composite insulator, so that each group of ultrasonic probes in the two groups of ultrasonic probes can detect N portions of ultrasonic detection results; S5, combining the N portions of ultrasonic detection results of the ultrasonic probes in the same group on the hollow composite insulator model to obtain two internal defect schematic diagrams of the hollow composite insulator respectively, and superimposing the corresponding two internal defect schematic diagrams to obtain an internal defect detection result of the hollow composite insulator.

2. The method of claim 1, wherein the method is characterized by: The pushing of the ring in the inner cavity of the hollow composite insulator is realized through the extension and retraction operation of the extension and retraction structure connected with the ring.

3. The method of claim 1, wherein the method is characterized by: The ring is assembled on a running frame, and the running frame is symmetrically provided with running wheels at the bottom, and the ring is pushed in the inner cavity of the hollow composite insulator through the running frame.

4. The method of claim 3, wherein the method further comprises: The running wheels are solid rubber wheels, and the outside thickness of the running wheels is smaller than the inside thickness to ensure the fit with the surface of the inner cavity of the hollow composite insulator.

5. The method of claim 1, wherein the method is characterized by: The data acquisition interval of the ultrasonic probe units in the two groups of ultrasonic probes is 0.5-0.6S, and the advancing speed of the ring in the inner cavity of the hollow composite insulator is not more than 30cm / S.

6. The method of claim 1, wherein the method is characterized by: The straight probes used in the ultrasonic probes are high-frequency straight probes of 115 sequences.

7. The method of claim 1, wherein the method is characterized by: The inclined probes used in the ultrasonic probes are low-frequency inclined probes of 115 sequences, and the slope of the inclined probes is controlled between K1.8 and K2.2.

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