Effect of nanoparticles on transformer oil breakdown strength: experiment and theory

Ibrahim, Mohamed E.; Abd‐Elhady, Amr M.; Izzularab, Mohamed A.

doi:10.1049/iet-smt.2016.0104

Cited by 64 publications

(61 citation statements)

References 15 publications

(27 reference statements)

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“…In conjunction with the applied electric field, particles can be easily charged and move to bridging the flow of electrons [20]. For highly-conductive nanoparticles, such as iron oxide, when the amount in natural ester is high, a smaller interparticle distance affects the electric field enhancement.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, for higher amounts of nanoparticles (0.1 and 1.0 g/L), the interparticle distance decreases, reducing the efficient width of double layers, and overlapping will potentially occur. In conjunction with the applied electric field, particles can be easily charged and move to bridging the flow of electrons [20]. For highly-conductive nanoparticles, such as iron oxide, when the amount in natural ester is high, a smaller interparticle distance affects the electric field enhancement.…”

Section: Discussionmentioning

confidence: 99%

“…When the electrical properties of a nanoparticle are different from the base oil, the electric field intensity surrounding the nanoparticle will be distorted. For instance as described in [20], a larger distortion of the electric field results in a higher magnitude of the electric field on the nanoparticle interface, subsequently exerting a force that attracts free electrons. Also, a high current density at the nanoparticle surface shows that streamer penetration can occur more easily with the presence of highly conductive nanoparticle in natural ester.…”

Section: Discussionmentioning

confidence: 99%

“…This is due to the effect of nanoparticle surface conductivity being more dominant. For semiconductive and dielectric nanofluids, reduction and overlapping of the interfacial zone space does not affect the dielectric response much because they can attract and trap electrons in shallow traps, as well as having very low conductivity values [20,34]. Nevertheless, if impurities exist on the particle surface, they play an important role in the mechanism, increasing the electrical conductivity of the base material [25].…”

Section: Discussionmentioning

confidence: 99%

“…However, it strongly depends on the potential mobility of charged particles in nanofluid due to electric field orientation. For instance, Ibrahim et al [20] reported that the increasing number of conductive nanoparticles (Fe 2 NiO 4 ) in the suspension will decrease the AC dielectric strength, and accumulated particles were observed at the electrode under the DC electric field. However, there is no general agreement regarding the influence of the conductivity and nanoparticle loading in nanofluid insulation.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Conductive and Semi-Conductive Nanoparticles on the Dielectric Response of Natural Ester-Based Nanofluid Insulation

et al. 2018

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Nowadays, studies of alternative liquid insulation in high voltage apparatus have become increasingly important due to higher concerns regarding safety, sustainable resources and environmentally friendly issues. To fulfil this demand, natural ester has been extensively studied and it can become a potential product to replace mineral oil in power transformers. In addition, the incorporation of nanoparticles has been remarkable in producing improved characteristics of insulating oil. Although much extensive research has been carried out, there is no general agreement on the influence on the dielectric response of base oil due to the addition of different amounts and conductivity types of nanoparticle concentrations. Therefore, in this work, a natural ester-based nanofluid was prepared by a two-step method using iron oxide (Fe 2 O 3 ) and titanium dioxide (TiO 2 ) as the conductive and semi-conductive nanoparticles, respectively. The concentration amount of each nanoparticle types was varied at 0.01, 0.1 and 1.0 g/L. The nanofluid samples were characterised by visual inspection, morphology and the dynamic light scattering (DLS) method before the dielectric response measurement was carried out for frequency-dependent spectroscopy (FDS), current-voltage (I-V), and dielectric breakdown (BD) strength. The results show that the dielectric spectra and I-V curves of nanofluid-based iron oxide increases with the increase of iron oxide nanoparticle loading, while for titanium dioxide, it exhibits a decreasing response. The dielectric BD strength is enhanced for both types of nanoparticles at 0.01 g/L concentration. However, the increasing amount of nanoparticles at 0.1 and 1.0 g/L led to a contrary dielectric BD response. Thus, the results indicate that the augmentation of conductive nanoparticles in the suspension can lead to overlapping mechanisms. Consequently, this reduces the BD strength compared to pristine materials during electron injection in high electric fields.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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