Nonlinear ultrasonic guide wave detection method for evaluation of contact state among conductor casing pipes

A non-linear ultrasonic and contact state technology, which is applied to the analysis of solids, materials, instruments, etc. using sound waves/ultrasonic waves/infrasonic waves, and can solve problems such as on-line detection in difficult-to-reach areas

Inactive Publication Date: 2018-09-28
BEIJING UNIV OF TECH
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Problems solved by technology

However, the above methods are all based on the body wave method to detect the structure, and cannot perform online detection on hard-to-reach areas.
[0007] At present, there are few reports on the use of nonlinear ultrasonic longitudinal guided waves to detect changes in pipe structures, especially solid-solid contact interfaces such as conductor sleeves.

Method used

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  • Nonlinear ultrasonic guide wave detection method for evaluation of contact state among conductor casing pipes
  • Nonlinear ultrasonic guide wave detection method for evaluation of contact state among conductor casing pipes
  • Nonlinear ultrasonic guide wave detection method for evaluation of contact state among conductor casing pipes

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Embodiment Construction

[0032] Below in conjunction with specific embodiment, the present invention will be further described:

[0033] The method for detecting the contact state of the conductor sleeve based on a nonlinear ultrasonic guided wave technology proposed by this method is realized through the following steps:

[0034] S1 press test system device figure 1 Connect the test equipment, arrange the ultrasonic excitation probe (7) at a distance of 480mm from the left end face, and arrange the ultrasonic receiving sensor (8) at a distance of 150mm from the left side of the excitation sensor.

[0035] S2 excitation signal parameter setting: including carrier signal amplitude, width, gated amplifier amplification level, modulation signal type, frequency, amplitude, phase, DC offset, etc., through the computer software to control the SNAP hardware system to send the excitation signal into the ultrasonic excitation probe (7).

[0036] S3 measures the frequency response characteristics of the excit...

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Abstract

The invention discloses a nonlinear ultrasonic guide wave detection method for evaluation of the contact state among conductor casing pipes. The method comprises the steps of firstly, preparing the conductor casing pipes in six different states in sequence, and stimulating a single longitudinal symmetric L(0,2) modality in a hanning mode based on a nonlinear ultrasonic detection system; adopting amethod for conducting FFT analysis on echo waves reflected by the end face of a contact interface to obtain spectrograms in different states, and meanwhile, extracting second harmonic amplitudes andthird harmonic amplitudes in different states for analysis. As is shown by results, along with the increase of contact pressure, the second harmonic amplitudes and third harmonic amplitudes all show the trend of gradual decrease. Finally, higher harmonic amplitudes represent different contact states of the conductor casing pipes. As is shown by the result, all the higher harmonic amplitudes can represent different contact states of the conductor casing pipes.

Description

technical field [0001] The invention relates to a nonlinear ultrasonic guided wave detection method for evaluating the contact state of conductor bushings, which can be used for non-destructive testing and safety evaluation of contact state changes between bushings, and belongs to the field of non-destructive testing. Background technique [0002] Due to its good ductility, high thermal conductivity and high electrical conductivity, copper sleeves are often used in the connection of aluminum alloy conductor tubes in gas-insulated combined electrical appliances (GIS (Gas Insulated Switchgear). Due to equipment aging and product assembly tolerances being too large, it is easy to cause poor contact between the aluminum alloy conductor tube and the copper sleeve, resulting in thermal faults. safe and stable operation. [0003] Existing methods for detecting the contact state of the conductor casing in the GIS cavity mainly include endoscopy, X-ray detection, and personnel entry...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/11
CPCG01N29/11G01N2291/015G01N2291/023G01N2291/02872G01N2291/102
Inventor 焦敬品褚运通
Owner BEIJING UNIV OF TECH
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