Location of partial discharges sources using sensor arrays

Polak, Filip; Sikorski, Wojciech; Siodła, Krzysztof

doi:10.1109/ichve.2014.7035465

Cited by 17 publications

(15 citation statements)

References 6 publications

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“…Location of the PD sources in power transformers is usually carried out using the time difference of arrival technique [16,46] or the standard auscultatory technique (SAT) [47]. In addition, research on the application of the direction of arrival (DOA) technique and sensor arrays has been carried out for several years [48][49][50][51][52].…”

Section: Test Of the Pd Source Location Using The Active Dielectric Wmentioning

confidence: 99%

Active Dielectric Window: A New Concept of Combined Acoustic Emission and Electromagnetic Partial Discharge Detector for Power Transformers

Sikorski

2018

Energies

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The detection and location of partial discharge (PD) is of great significance in evaluating the insulation condition of power transformers. This paper presents an active dielectric window (ADW), which is a new concept of combined acoustic emission (AE) and electromagnetic PD detector intended for assembly in a transformer’s inspection hatch. The novelty of this design lies in the fact that all structural components of an ultrasonic transducer, i.e., the matching and backing layer, an active piezoelectric element with electrodes, and electrical leads, were built into a dielectric window. Due to the fact that its construction was optimized for work in mineral oil, it is characterized by much higher sensitivity of PD detection than a general-purpose AE sensor mounted outside a transformer tank. Laboratory tests showed that the amplitude of the AE pulses generated by creeping discharges, which were registered by the ADW, was around five times higher on average than the pulses registered by a commonly used contact transducer. A possibility of simultaneous detection of acoustic and electromagnetic pulses (with an integrated ultra-high frequency (UHF) antenna) is an important advantage of the ADW. It allows for an increase in the reliability of PD detection, the accuracy of defect location, and the effectiveness of disturbance identification. This paper describes in detail the applied methods of designing and modeling the ADW components, the manufacturing process of the prototype construction, and the results of preliminary laboratory tests, in which the detector’s sensitivity as well as the efficiency of the PD source location were evaluated.

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Section: Test Of the Pd Source Location Using The Active Dielectric Wmentioning

confidence: 99%

Active Dielectric Window: A New Concept of Combined Acoustic Emission and Electromagnetic Partial Discharge Detector for Power Transformers

Sikorski

2018

Energies

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“…Mainly for that reason, online monitoring systems available on the market or currently developed by research centers are based only on unconventional PD detection methods. This group includes dissolved gas analysis (DGA) in oil [18,19,20], detection of electromagnetic waves in the high-frequency (HF) [21,22] and ultrahigh frequency (UHF) ranges [23,24,25,26,27], and the acoustic emission method (AE), which, apart from detection and on-line monitoring of PD, also locates PD sources [28,29,30,31,32]. It should be underlined that sensitivity of these techniques highly depends on sensor position in a power transformer tank and its distance from the PD source as well as on the construction and parameters of the sensor [33].…”

Section: Introductionmentioning

confidence: 99%

Development of Acoustic Emission Sensor Optimized for Partial Discharge Monitoring in Power Transformers

Sikorski

2019

Sensors

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The acoustic emission (AE) technique is one of the unconventional methods of partial discharges (PD) detection. It plays a particularly important role in oil-filled power transformers diagnostics because it enables the detection and online monitoring of PDs as well as localization of their sources. The performance of this technique highly depends on measurement system configuration but mostly on the type of applied AE sensor. The paper presents, in detail, the design and manufacturing stages of an ultrasensitive AE sensor optimized for partial discharge detection in power transformers. The design assumptions were formulated based on extensive laboratory research, which allowed for the identification of dominant acoustic frequencies emitted by partial discharges in oil–paper insulation. The Krimholtz–Leedom–Matthaei (KLM) model was used to iteratively find optimal material and geometric properties of the main structures of the prototype AE sensor. It has two sensing elements with opposite polarization direction and different heights. The fully differential design allowed to obtain the desired properties of the transducer, i.e., a two-resonant (68 kHz and 90 kHz) and wide (30‒100 kHz) frequency response curve, high peak sensitivity (−61.1 dB ref. V/µbar), and low noise. The laboratory tests confirmed that the prototype transducer is characterized by ultrahigh sensitivity of partial discharge detection. Compared to commonly used commercial AE sensors, the average amplitude of PD pulses registered with the prototype sensor was a minimum of 5.2 dB higher, and a maximum of 19.8 dB higher.

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“…Moisture in cellulose insulation is a very serious operational threat to transformers. Moisture reduces insulation material resistivity [13] and dielectric strength [14] which decreases the partial discharge inception voltage and increases transformer failure probability [15][16][17][18][19][20][21]. In addition, moisture increases dielectric losses in cellulose insulation [22,23], which increases its temperature and thus shortens its lifetime.…”

Section: Introductionmentioning

confidence: 99%

Application of Synthetic Ester for Drying Distribution Transformer Insulation—The Influence of Cellulose Thickness on Drying Efficiency

et al. 2019

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A high level of insulation moisture in a transformer increases the breakdown probability and forces a reduction of its load. Therefore, there is a need to dry the transformer insulation. For technical reasons, there are some restrictions on the use of common drying methods for cellulose insulation available on the market. The aim of the research was to check the possibility of using synthetic ester for effective drying of cellulose materials of various thickness and an evaluation of the drying dynamics. The replacement of mineral oil with a synthetic ester caused a reduction of moisture in paper and thin pressboard by one percentage point. It was possible in the case of drying these materials for seven days at a temperature of 70 °C. The effects of drying were much smaller in the case of thicker cellulose samples. This paper also shows the complex problem of simultaneously drying materials of different thicknesses. Drying thin paper and thick pressboard at the same time significantly slows down the drying process of the pressboard. Presented results will be used to develop a procedure for drying the transformer insulation system using a synthetic ester.

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Location of partial discharges sources using sensor arrays

Cited by 17 publications

References 6 publications

Active Dielectric Window: A New Concept of Combined Acoustic Emission and Electromagnetic Partial Discharge Detector for Power Transformers

Active Dielectric Window: A New Concept of Combined Acoustic Emission and Electromagnetic Partial Discharge Detector for Power Transformers

Development of Acoustic Emission Sensor Optimized for Partial Discharge Monitoring in Power Transformers

Application of Synthetic Ester for Drying Distribution Transformer Insulation—The Influence of Cellulose Thickness on Drying Efficiency

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