Diagnostic challenges in dielectric loss assessment and interpretation: a review

Morsalin, S.; Phung, B.T.; Danikas, M. G.; Mawad, Damia

doi:10.1049/iet-smt.2018.5597

Cited by 34 publications

(18 citation statements)

References 88 publications

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“…With respect to materials research, further work has to be performed regarding the surface discharges in LN 2 /polymeric insulation uniform electrode arrangements [65]. Moreover, very low frequency (VLF) measurements regarding the insulation at cryogenic temperatures may offer an effective diagnostic technique to assess early insulation degradation [66][67][68]. Partial discharges due to defects must be further explored with insulating systems at very low temperatures both w.r.t their mechanisms and classification, as was done with conventional polymers at normal temperature with isolated as well as multiple defects [69,70].…”

Section: Discussion and Proposals For Future Resdearchmentioning

confidence: 99%

Insulating Materials at Very Low Temperatures: A Short Review

Malelis

Danikas

2020

Eng. Technol. Appl. Sci. Res.

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In this paper, a short review is given on insulating materials at very low temperatures. Various insulating materials are investigated in terms of phenomena such as partial discharges. Some of the factors affecting the behavior of the insulating materials at very low temperatures, such as the quality of electrode surface, the stressed insulation volume and the existing bubbles, are also reported and commented upon. Proposals for future research are also discussed.

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Section: Discussion and Proposals For Future Resdearchmentioning

confidence: 99%

Insulating Materials at Very Low Temperatures: A Short Review

Malelis

Danikas

2020

Eng. Technol. Appl. Sci. Res.

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“…However, its low thermal conductivity and thermal stability seriously restrict the development of electronic devices 4 . The heat generated during the equipment's operation cannot be rapidly dissipated and decreases the dielectric strength and insulation lifetime of the materials 5,6 . Therefore, it is essential to study EP's thermal and electrical properties to ensure the reliable operation of the electronic devices 7 …”

Section: Introductionmentioning

confidence: 99%

Influences of nanoparticle content on electrical and thermal performances of micro‐nano hybrid composites for packaging materials

Dai

Chen

Meng

et al. 2021

J of Applied Polymer Sci

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This paper presents electrical and thermal properties of a novel type of micro‐nano hybrid composites to be potential for packaging. The micro‐nano hybrid composites contain 20 wt% of micro‐aluminium nitride (AlN) with 1, 3, and 5 wt% of nano‐AlN, respectively. Electrical measurement and thermal analysis are used to analyze the performances. The results show that the nano‐AlN in the hybrid composites can suppress the space charge accumulation near the cathode and facilitate the conversion of hetero charge into the homo‐charge accumulations near the anode. No apparent electric field distortion can be observed in the M20N3 sample, whereas it exhibits a minimum electrical conductivity and highest thermal conductivity amongst all samples. Furthermore, the nano‐filler addition can enhance the DC breakdown strength and the thermal stability of the hybrid composites. The thermal and electrical conduction mechanism of the micro and nano fillers in the hybrid composites is also elucidated.

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“…The time and frequency domain non‐destructive testing technologies are applied to transformer insulation ageing assessment [12–14]. Among them, frequency domain dielectric response technology (FDS) is more widely used.…”

Section: Introductionmentioning

confidence: 99%

Method for quantitative assessment of transformer oil‐paper insulation non‐uniform ageing parameters based on frequency domain dielectric response

Zhang

Liu³

et al. 2021

IET Science Measure & Tech

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The stable operation of transformers is an important guarantee of power system security. The temperature distribution of main insulation is different in long‐term operation. The temperature difference between the local hottest spot temperature and the average oil temperature in the transformer exceeds 30 K. Therefore, the oil‐paper insulation inside the transformer will exhibit non‐uniform ageing after long‐term operation. At present, frequency domain dielectric response (FDS) technology is widely used in transformer ageing assessment. However, the existing assessment methods are only used for overall insulation ageing assessment. The average moisture content and polymerization degree of the overall insulation between each phase winding are obtained. But it still cannot be used to assess the non‐uniform ageing of the transformer's main insulation. The radial, axial, and two directions non‐uniform ageing models have been made in the laboratory in this study. The FDS and physicochemical properties of non‐uniform ageing models were tested. The variation law of FDS for non‐uniform ageing models was analysed. Meanwhile, the dielectric relaxation model of non‐uniform ageing for main insulation was established. The method of frequency division iterative calculation was proposed. Combined with the Fessler moisture balance formula of ageing oil‐paper insulation, the quantitative assessment method for ageing parameters of the non‐uniform ageing model can be realized. Compared the calculated results with the chemical analysis results, the relative error of the polymerization degree calculation is less than 4%, and the error of the moisture content calculation is less than 0.3%. The calculation results can meet the needs of the engineering apply. Therefore, this method can realize the quantitative assessment of transformer main insulation ageing, which is of great significance to assess the transformer insulation state.

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Diagnostic challenges in dielectric loss assessment and interpretation: a review

Cited by 34 publications

References 88 publications

Insulating Materials at Very Low Temperatures: A Short Review

Insulating Materials at Very Low Temperatures: A Short Review

Influences of nanoparticle content on electrical and thermal performances of micro‐nano hybrid composites for packaging materials

Method for quantitative assessment of transformer oil‐paper insulation non‐uniform ageing parameters based on frequency domain dielectric response

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