Breakdown Performance and Partial Discharge Development in Transformer Oil-Based Metal Carbide Nanofluids

Κούτρας, Κωνσταντίνος; Tegopoulos, Sokratis N.; Charalampakos, Vasilios P.; Kyritsis, Apostolos; Gonos, Ioannis F.; Pyrgioti, E.

doi:10.3390/nano12020269

Cited by 25 publications

(22 citation statements)

References 41 publications

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“…Extreme value (EV), normal, and Weibull distributions are used to analyze and test the conformity of breakdown voltage outcomes. Contrary to the popular statistical laws (i.e., Weibull and normal) [16,20,25,31], EV has been rarely considered to adjust the experimental AC BDV outcomes [13]. EV distribution combines Gumbel, Frechet, and Weibull distribution [13]; hence probability fit curves of the experimental results are plotted using EV and normal distribution.…”

Section: Statistical Analysis Of Ac Breakdown Voltage Datamentioning

confidence: 99%

“…5a,b. The BDV at 1% and 10% risk levels (U 1% and U 10% ) are essential information about the reliability of the HV apparatuses since they represent their voltage limit for safe/continuous operation and the lowest possible AC BDV, while the BDV at 50% (U 50% ) is an estimation of the expected mean BDV [25].…”

Section: Statistical Analysis Of Ac Breakdown Voltage Outcomes For 2 ...mentioning

confidence: 99%

“…From those plots, the BDV at risk levels (1%, 10%, and 50%) are evaluated from normal and EV distribution fit curves and presented in Table 5a,b. The BDV at 1% and 10% risk levels (U1% and U10%) are essential information about the reliability of the HV apparatuses since they represent their voltage limit for safe/continuous operation and the lowest possible AC BDV, while the BDV at 50% (U50%) is an estimation of the expected mean BDV [25]. show the normal and EV probability density plot of Fe3O4 (20 nm), ZnO (20 nm), ZrO2 (20-30 nm), SiO2 (10-20 nm), Al2O3 (20-30 nm), and Al2O3 (50 nm) NFs versus AC BDV for different concentrations; they show how the breakdown data fit each case's corresponding normal and EV probability lines.…”

Section: Statistical Analysis Of Ac Breakdown Voltage Outcomes For 2 ...mentioning

confidence: 99%

“…They concluded that the smaller the EDL, the lower the PD activity. Recently, Khelifa et al [20] and Koutras et al [25] reported that the addition of carbonic (C 60 ) and silicon carbide (SiC) NPs enhances the PD resistivity of pure synthetic ester (MIDEL 7131) and natural ester (FR3), respectively.…”

Section: Introductionmentioning

confidence: 99%

“…From those plots, the BDV at risk levels (1%, 10%, and 50%) are evaluated from normal and EV distribution fit curves and presented in Table5a,b. The BDV at 1% and 10% risk levels (U 1% and U 10% ) are essential information about the reliability of the HV apparatuses since they represent their voltage limit for safe/continuous operation and the lowest possible AC BDV, while the BDV at 50% (U 50% ) is an estimation of the expected mean BDV[25].It resorts from the results in Table5a,b that the addition of the Fe 3 O 4 (20 nm), ZnO (25 nm), ZrO 2 (20-30 nm), SiO 2 (10-20 nm), Al 2 O 3 (20-30 nm), and Al 2 O 3 (50 nm) NPs could not only enhance the mean AC BDV (from 50% risk level) but also improve the AC BDV at 1% and 10% risk levels. Mainly, the addition of these NPs strongly affects the U 1% rather than U 10% and U 50% , exceeding 75% of improvement withFe 3 O 4 (20 nm) and Al 2 O 3 (20-30 and 50 nm) compared to pure SE.…”

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confidence: 99%

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Effect of Conducting, Semi-Conducting and Insulating Nanoparticles on AC Breakdown Voltage and Partial Discharge Activity of Synthetic Ester: A Statistical Analysis

2022

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This paper is aimed at studying the influence of conducting (Fe3O4), semi-conductive (ZnO), and insulating (ZrO2, SiO2, and Al2O3) nanoparticles (NPs) at various concentrations on the AC dielectric strength of MIDEL 7131 synthetic ester (SE) and partial discharges activity. First, a detailed and improved procedure for preparing nanofluids (NFs) in five concentrations ranging from 0.1 g/L to 0.5 g/L is presented, including high-speed agitation and ultrasonication. Then, the long-term stability is checked based on zeta potential analysis. After preparing and characterizing the NF samples, the following step is to measure their AC breakdown voltage (BDV). Due to the limitation of the high voltage supply (Baur system), the tests are performed according to IEC 60156 standard (2.5 mm gap distance) only with ZnO, ZrO2, and SiO2 NPs, and for comparison, tests are executed for all considered NPs with an electrodes gap of 2 mm. It is shown that the addition of Fe3O4 (20 nm), ZnO (25 nm), ZrO2 (20–30 nm), SiO2 (10–20 nm), Al2O3 (20–30 nm), and Al2O3 (50 nm) NPs improves the dielectric strength of synthetic ester upon an optimal concentration which gives the highest AC BDV. SiO2 (10–20 nm) and Al2O3 (20–30 nm) manifest their best improvement at 0.3 g/L, while for the other NFs, the best improvement is observed at 0.4 g/L. Further, the Anderson–Darling goodness-of-fit test is performed on the experimental data to check their conformity with the Extreme value (EV), normal, and Weibull distributions; the normal and EV fit curves are plotted and used to evaluate the breakdown voltages at probabilities of 1%, 10%, and 50%. It is shown that the AC breakdown voltage outcomes for most investigated nanofluids mostly obey the three EV, normal, and Weibull distributions. Then, the best combinations (nature of NP and optimal concentration), namely Fe3O4 (20 nm, 0.4 g/L), Al2O3 (20–30 nm, 0.3 g/L), and Al2O3 (50 nm, 0.4 g/L) NPs, that highly enhance the AC BDV of SE are chosen for a partial discharge activity investigation and comparison with pure SE. It is shown that the addition of those NPs significantly reduces the activity of partial discharges compared to pure SE.

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Section: Statistical Analysis Of Ac Breakdown Voltage Datamentioning

confidence: 99%

Section: Statistical Analysis Of Ac Breakdown Voltage Outcomes For 2 ...mentioning

confidence: 99%

Section: Statistical Analysis Of Ac Breakdown Voltage Outcomes For 2 ...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…From those plots, the BDV at risk levels (1%, 10%, and 50%) are evaluated from normal and EV distribution fit curves and presented in Table5a,b. The BDV at 1% and 10% risk levels (U 1% and U 10% ) are essential information about the reliability of the HV apparatuses since they represent their voltage limit for safe/continuous operation and the lowest possible AC BDV, while the BDV at 50% (U 50% ) is an estimation of the expected mean BDV[25].It resorts from the results in Table5a,b that the addition of the Fe 3 O 4 (20 nm), ZnO (25 nm), ZrO 2 (20-30 nm), SiO 2 (10-20 nm), Al 2 O 3 (20-30 nm), and Al 2 O 3 (50 nm) NPs could not only enhance the mean AC BDV (from 50% risk level) but also improve the AC BDV at 1% and 10% risk levels. Mainly, the addition of these NPs strongly affects the U 1% rather than U 10% and U 50% , exceeding 75% of improvement withFe 3 O 4 (20 nm) and Al 2 O 3 (20-30 and 50 nm) compared to pure SE.…”

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confidence: 99%

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