The study of acoustic emission method for detection of partial discharge in power transformer

Zhu, Dejun; Tan, Kexiong; Xianhe, Jin

doi:10.1109/icpadm.1988.38472

Cited by 20 publications

(6 citation statements)

References 3 publications

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“…The MAE minimum is in the vicinity of coercive point H C . Deheng et al (1988) show that the main frequency band for the magnetoacoustic emission phenomenon in investigations of transformers is 20-65 kHz, whereas the total band for the phenomena associated with the magnetization of transformer core sheets (HEB + MAE) is 10-65 kHz. Howells et al (Howells, Norton, 1978) determine the frequency range of magnetic noise as 30-60 kHz.…”

Section: Magnetic Phenomena In Ferromagnetic Materialsmentioning

confidence: 94%

Identification of Acoustic Emission Signals Originating from the Core Magnetization of Power Oil Transformer

Olszewska

Witos

2016

Archives of Acoustics

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In this paper, the properties of AE signals originating from phenomena occurring during magnetization of ferromagnetic materials which are used to construct power transformer cores are presented. The AE signals in a selected power oil transformer were recorded and analyzed. The analysis included, i.e., time, frequency, and time-frequency analyses, calculations of amplitude distributions of the signals and defined AE descriptors, determination of the descriptor map on the side walls of transformers, as well as a detailed analysis of selected part of the signals.The maps of descriptors were analyzed in the frequency bands of 20-70 kHz, 70-100 kHz, and 100-200 kHz. The analysis of the properties of the signals was performed in time and frequency domains. Based on the analysis, there were identified the AE signals originating from the phenomena occurring during the core magnetization of a power oil transformer. To identify those phenomena, the maps of the ADC descriptor calculated in the band of 20-70 kHz when selecting the measurement points in which there were no AE sources from partial discharges were used.An analysis of magnetoacoustic emission signals in the bands of 70-100 kHz and 100-200 kHz was also performed. The analysis of the signal properties in such an extended frequency range allowed determining the properties of the magnetoacoustic signals coming from core sheets of power oil transformers.Keywords: power oil transformers; magnetization of transformers cores; magnetoacoustic emission. Magnetic phenomena in ferromagnetic materialsPhenomena in ferromagnetic materials are one of the sources of acoustic signals in power oil transformers. During the magnetization of ferromagnetic materials which are used to construct transformer core laminations, there occurs the reversible movement of domain boundaries (the so-called Bloch walls), irreversible movement of domain boundaries (Barkhausen effect), and rotation of magnetization vectors in the direction of the external magnetic field. Within these processes, there occur processes of creation of domain boundaries, movement of these boundaries, and their annihilation.The Barkhausen jump results in (i) the generation of an electromagnetic wave (Barkhausen field effect -HEB), (ii) a local change of the magnetization and defects in the crystal lattice and (iii) the generation of an acoustic wave (magnetoacoustic emission effect).The phenomenon of magnetoacoustic emission (MAE) consists in generating a sound wave by a jump motion of a 90• domain wall in a material with nonzero magnetostriction (Augustyniak, 1999). A MAE signal depends not only on the microstructure, stresses or the magnetization frequency, but also on the geometry of the sample and its demagnetization. MAE has a relatively short history. It was first reported by A.E. Lord in the middle 1970 -s (Lord,1975. He called that effect "the acoustic Barkhausen effect" by analogy with "the classic Barkhausen effect". Elastic waves generated during MAE are caused by changes in magnetostrictive stresses during t...

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Section: Magnetic Phenomena In Ferromagnetic Materialsmentioning

confidence: 94%

Identification of Acoustic Emission Signals Originating from the Core Magnetization of Power Oil Transformer

Olszewska

Witos

2016

Archives of Acoustics

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“…This fact is used by acoustic emission partial discharge monitoring methods, where emitted waves are captured by piezo-electric sensors mounted on the external wall of the transformer tank. The dominant frequencies observed of recorded PD signals typically lie in the range of 70 kHz to 180 kHz [23], which are quite higher when compared to the signals generated by transformer vibrations or OLTC operation. Besides accelerometers, some researchers also used other types of sensors such as hydrophone [19] or strain gauge sensors [24].…”

Section: Diagnostic Data Collection and Preprocessing A Diagnostic Data Collectionmentioning

confidence: 94%

Vibro-Acoustic Methods in the Condition Assessment of Power Transformers: A Survey

2019

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It has been over two decades since the publication of pioneer works about the power transformer diagnostics based on monitoring of their acoustic fingerprints. Since then, there has been great progress in this field and the methods used are as complex as ever. Any unnecessary intervention on a power transformer implies its temporary disconnection from the power grid. The inability to supply electricity to the customer means not only financial loss for the utility but also generates a non-material loss, e.g., the loss of reputation to the customer. Faster, more accurate, more reliable, and less invasive diagnosis is the main reason behind development and improvement in this field. The main goal of this paper is to categorize and review state-of-the art of vibro-acoustic diagnostic methods for power transformers. This paper opens with a brief note about continuous condition monitoring, after which we overview the causes of transformer vibrations as well as the collection and preprocessing of diagnostic data. Then, we review and categorize works related to the acoustic condition assessment of power transformers considering both: feature extraction in the time, frequency, time-frequency domain, and mathematical modeling and system identification of dynamic systems.

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“…However, along with them, there are different methods useful for evaluation of the phenomena accompanied with PDs [3][4][5]. Among them the leading role is played by the chemical methods with dissolved gas analysis (DGA) [6][7] and the acoustic emission (AE) method [8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, fortunately, the development of measurement methods and methods of data analysis constantly reduces the main difficulties and limitations of acoustic methods. In the literature there are presented solutions based on recording and analysis of signals in different frequency bands: 70-180 kHz [8,10], 100-200 kHz [11], building expert systems involving multiple descriptors describing signals recorded in research carried out in several ways [16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Metrology and Measurement Systems

Witos

Opilski

Szerszeń

et al. 2019

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A computer measurement system, designed and built by authors, dedicated to location and description of partial discharges (PD) in oil power transformers examined by means of the acoustic emission (AE) method is presented. The measurement system is equipped with 8 measurement channels and ensures: monitoring of signals, registration of data in real time within a band of 25-1000 kHz in laboratory and real conditions, basic and advanced analysis of recorded signals. The basic analysis carried out in the time, frequency and time-frequency domains deals with general properties of the AE signals coming from PDs. The advanced analysis, performed in the discrimination threshold domain, results in identification of signals coming from different acoustic sources as well as location of these sources in the examined transformers in terms of defined by authors descriptors and maps of these descriptors on the side walls of the tested transformer tank. Examples of typical results of laboratory tests carried out with the use of the built-in measurement system are presented.

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The study of acoustic emission method for detection of partial discharge in power transformer

Cited by 20 publications

References 3 publications

Identification of Acoustic Emission Signals Originating from the Core Magnetization of Power Oil Transformer

Identification of Acoustic Emission Signals Originating from the Core Magnetization of Power Oil Transformer

Vibro-Acoustic Methods in the Condition Assessment of Power Transformers: A Survey

Metrology and Measurement Systems

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