ACOUSTIC EMISSION TESTING OF POWER TRANSFORMERS INSULATION

2020 ◽  
pp. 40-44
Author(s):  
V. V. Bardakov ◽  
S. V. Elizarov ◽  
V. A. Barat ◽  
V. G. Kharebov ◽  
K. A. Medvedev
Keyword(s):  
Acoustic Emission ◽  
High Sensitivity ◽  
Partial Discharges ◽  
Power Transformers ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Emission Data ◽  
Emission Testing ◽  
Insulation Defect ◽  
Acoustic Emission Testing

Testing results of power transformers insulation for the presence of insulation defects, accompanied by the partial discharges occurrence, by means of the acoustic emission method are presented in this article. In particular, the testing of two power transformers with different lifetime was carried out. One transformer was defect-free and one with a willing insulation defect. Based on the testing results, the features of acoustic emission data for power transformers in the presence of partial discharges are found. High sensitivity of acoustic emission method for acoustic wave registration from partial discharges is shown in the article. A method for filtering of noise hits and extraction of hits from partial discharges is proposed. This method is based on excretion of acoustic emission hits from partial discharges out of total number of hits by means of periodicity of their registration, which is synchronized with power supply frequency on the first step. On the next step based on acoustic emission parameters of hits excretion on the previous step, filtration was carried out. The location of the insulation defect which led to the appearance of partial discharges was determined based on the volume location algorithm, by means of acoustic emission method. The insulation defect was confirmed by verification.

scholarly journals Features of Noise Filtering During Acoustic Emission Testing

2019 ◽  
Vol 9 (1) ◽  
pp. 3977-3980
Keyword(s):  
Acoustic Emission ◽  
Acoustic Noise ◽  
Low Noise ◽  
Non Destructive Testing ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Destructive Testing ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Non Destructive

This article discusses the problems of the acoustic emission method of non-destructive testing. An approach to filtering noise arising from monitoring of acoustic emission is considered. The filtering of acoustic noise is one of the key problems of the acoustic emission method, since the low noise immunity of the acoustic emission method prevents the expansion of its industrial application. The complexity of the filtering is explained by the fact that the waveform and spectrum of acoustic emission pulses change depending on the distance between the defect, which is the source of acoustic emission waves, and the sensor. In turn, the interference, as a rule, is non-stationary in nature and is determined by the type of technological process of the tested composition. This article discusses various types of noise processes, both stationary and non-stationary. The signal and noise parameters are compared, based on which recommendations are given for constructing algorithms for detecting acoustic emission pulses against a background of noise.

scholarly journals ACOUSTIC EMISSION TESTING OF FIBERGLASS PIPES AND FITTINGS

2021 ◽  
pp. 12-25
Author(s):  
S. V. Elizarov ◽  
D. A. Terentyev ◽  
K. A. Medvedev ◽  
V. I. Ivanov ◽  
A. G. Halimov ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Residual Life ◽  
Early Stage ◽  
Experimental Studies ◽  
Operating Mode ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Dimensional Inspection ◽  
Emission Testing ◽  
Acoustic Emission Testing

Experimental studies was carried out. The purpose was to develop a method to test fiberglass pipelines in operating mode. The acoustic emission method was chosen as the main method of nondestructive testing, and visual and dimensional inspection was chosen as an additional method. Acoustic parameters and acoustic emission properties of fiberglass pipes were determined. It was found that acoustic emission sensors can be installed at distances of up to 9-18 m from each other. A series of loading tests was carried out to refine the methodology. Every loading case was performed until leakage registration. In most cases, leakage occurred near the fillet at pressures of 2.2…3.0 from the working pressure, which indicates a large margin of safety for fiberglass pipes. It is confirmed that the acoustic emission method allows early defect detection. Based on the acoustic emission data, 4 main stages of fiberglass pipes degradation were identified. Visual and dimensional inspection was informative only at stages III – IV. Stage IV in most cases corresponds to the leakage. Even early stage of depressurization was registered as continuous acoustic emission. Signals with amplitudes exceeding 60…80 dB were registered at all loading stages. The location map became informative after filtering events by acoustic emission parameters. A methodology for the testing of fiberglass pipes and fittings in operating mode was developed. It contains, in contrast to the currently valid standards, specific numerical values of various quantities related to both the preparation and carrying out of acoustic emission testing and the classification of the identified sources of acoustic emission according to the degree of danger and allows to evaluate the residual life of fiberglass pipelines. The most informative parameter was the activity of acoustic emission; therefore, it is recommended to carry out loading without holding the pressure. It is planned to carry out additional experiments to clarify the mechanisms of fracture acting at each of the 4 identified stages of degradation.

scholarly journals Calibration and Laboratory Testing of Computer Measuring System 8AE-PD Dedicated for Analysis of Acoustic Emission Signals Generated by Partial Discharges Within Oil Power Transformers

2017 ◽  
Vol 42 (2) ◽  
pp. 297-311 ◽  
Author(s):  
Franciszek Witos ◽  
Grzegorz Szerszeń ◽  
Zbigniew Opilski ◽  
Maciej Setkiewicz ◽  
Aneta Olszewska ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Steel Plate ◽  
Partial Discharges ◽  
Measuring System ◽  
Power Transformers ◽  
General Description ◽  
Emission Method ◽  
Peak Voltage ◽  
Limit Values ◽  
Ae Signals

Abstract In the paper, there are presented a general description of the constructed measuring system 8AE-PD, the results of calibration of this system by the Hsu-Nielsen method as well as the testing of the measuring system during recording signals generated by Hsu-Nielsen sources in a steel plate and a modeled partial discharge (PD) source. There is also presented the methodology of investigations by the calibrated acoustic emission method. The results of analyses of PD signals coming from the modeled sources are given. In particular, there are described the properties of acoustic emission (AE) signals generated by the PDs as well as the dependencies of the peak-to-peak voltage Umm, the RMS voltage Urms and the descriptors of acronyms ADP and ADC on the apparent charge Q introduced by the modeled PD source. There are determined the limit values of the apparent charge Q introduced by the modeled PD source for which the recorded signal is identified as originating from the PDS.

Development of Acoustic Emission Sensor Based on the 0-3 PZT/P(VDF-TFE) Piezoelectric Composite

2014 ◽  
Vol 487 ◽  
pp. 58-62
Author(s):  
Jun Kang ◽  
Peng Sheng Xie ◽  
Yuan Li ◽  
Jia Lin Zhu ◽  
Li Li
Keyword(s):  
Acoustic Emission ◽  
High Sensitivity ◽  
Fast Response ◽  
Piezoelectric Composite ◽  
Acoustic Emission Sensor ◽  
Film Sensor ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Pencil Lead ◽  
Discharge Method

In this paper, we produced the 0-3 PZT/P(VDF-TFE) piezoelectric composite film with 80μm thickness using PZT piezoelectric ceramics and fluorine resin P(VDF-TFE) by weight 85/15 ingredients through the hot rolling machine and corona-discharge method. A sensor with 4cm×1.3cm area is designed and produced by using this film. We have carried out the breaking of a pencil lead pressed against an aluminum plate acoustic emission testing. The result shown that the sensor is with fast response and high sensitivity advantage, the sensor can be used as acoustic emission sensor. Meanwhile the sensor is very easy to use due to it is a soft film sensor.

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