Variability of the UHF Signals Generated by Partial Discharges in Mineral Oil

Kunicki, Michał

doi:10.3390/s19061392

Cited by 20 publications

(14 citation statements)

References 39 publications

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“…Under aeronautic conditions, however, the most accurate methods are be those based on EM radiation detection. Special attention should be paid to the detection of high-energy radiation [21] and the very popular UHF method [22,23], which extend the range of EM wavelength detection to longer and shorter wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Optical Radiation from an Electric Arc at Different Frequencies

2020

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The article presents research on the electric arc generated by AC current at different frequencies. The measurement procedure and system are described. Optical spectra of the generated arc in the air were recorded using a spectrophotometer. Optical spectra for five frequencies were obtained. The article also presents the energy balance of the components of the registered spectrum. The visible changes in the spectra that depend on the frequency of the AC current generating the electric arc can be significant to the diagnostics of gas insulators. The research presented in the article can be used in multiple areas of technology where an electric arc is used. The influence of the frequency of the current supplying the electric arc on the electromagnetic radiation spectrum in the area of light radiation emitted by the electric arc allows for the construction of systems that can shape the desired characteristics of the electric arc.

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Section: Introductionmentioning

confidence: 99%

Optical Radiation from an Electric Arc at Different Frequencies

2020

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“…The measurement systems and methodology are presented, e.g., in [16,17]. The electromagnetic radiation coming from PD is also registered in the Ultra high frequency (UHF) range [18] and high ionizing energies [19,20]. Not only measuring devices, systems, and methods, but also all kinds of descriptors have been developed to assess the damage in both liquid and gas and solid insulators.…”

Section: Introductionmentioning

confidence: 99%

Electrical Strength of Natural Esters Doped by Iron Nanopowder in a Hydrophobic Carbon Shell

Nagi¹,

Płużek²

2020

Materials

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The paper presents the results of measurements of electrical strength of Midel 1204 natural ester doped with iron nanopowder in a hydrophobic carbon shell. The research was conducted for different concentrations of the dopant. The samples were prepared in the High Voltage Technique Laboratory. After mixing, they were tightly closed, and the first measurements were taken after 5 weeks of dissolution of the dopant in liquid. The tests were repeated after another 2 weeks and 3 weeks of dissolution of nanoparticles. An increase in both mean and maximum breakdown voltage was shown for the tested liquid mixtures. The concentration for which the value of electrical strength begins to decrease was indicated. It was also shown that a longer time of dissolution of nanoparticles causes an increase in the electric strength value for the tested samples.

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“…Combined UHF and acoustic sensors have been investigated to reduce the negative effect of the stiff structure of the transformer tank on acoustic signals and, therefore, increase the accuracy of PD localization [20,21]. Experimental investigations showed that the UHF method can detect small PD levels with good sensitivity [22,23], even when they are buried within insulation layers [24]. In contrast, the acoustic method can detect small PD levels only when the PD is in direct line of sight of the sensor [24].…”

Section: Introductionmentioning

confidence: 99%

Calibration Proposal for UHF Partial Discharge Measurements at Power Transformers

Siegel¹,

Coenen

Beltle

et al. 2019

Energies

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The continuous, non-intermitted service of electrical grids relies on the reliability of their assets, e.g., power transformers. Local insulation defects can result in serve failures such as breakdowns with severe subsequent costs. The prevention of such events is crucial. Hence, partial discharge (PD) activity at power transformers is evaluated directly in the factory before shipment. Additionally, PD activity can be monitored during service using the ultra-high frequency (UHF) method. In this contribution, a calibration procedure is proposed for the UHF method. The calibration process is required to ensure both, reproducibility and comparability of UHF measurements: Only a calibrated UHF measurement procedure can be introduced supplementary to IEC 60270 in acceptance tests of power transformers. The proposed calibration method considers two factors: The influence of the UHF-antenna's sensitivity and the PD recorder characteristics including accessories such as cable damping, pre-amplifier, etc. The former is addressed by a characterization of UHF sensors using the standard antenna factor (AF) in a gigahertz transverse electromagnetic (GTEM) cell. The PD recorder's influence is corrected by using a defined, invariable test signal as reference for all recording devices. A practical evaluation of the proposed calibration procedure is performed in a laboratory setup using different UHF recording devices and UHF sensors using artificial PD signals and real voltage-driven PD sources.

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Variability of the UHF Signals Generated by Partial Discharges in Mineral Oil

Cited by 20 publications

References 39 publications

Optical Radiation from an Electric Arc at Different Frequencies

Optical Radiation from an Electric Arc at Different Frequencies

Electrical Strength of Natural Esters Doped by Iron Nanopowder in a Hydrophobic Carbon Shell

Calibration Proposal for UHF Partial Discharge Measurements at Power Transformers

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