Development of a Biodegradable Electro-Insulating Liquid and Its Subsequent Modification by Nanoparticles

Mentlík, Václav; Trnka, Pavel; Hornak, Jaroslav; Totzauer, Pavel

doi:10.3390/en11030508

Cited by 35 publications

(15 citation statements)

References 35 publications

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“…On the other hand, the behavior of dispersed conductive fillers is very-well known [45,46,47,48] and percolation threshold could be estimated based on the significant increase of conductivity. However, the dielectric parameters of basic material could be improved by addition of relatively low amount of nanofiller, as is evident from our previous studies [49,50,51]. In connection with these claims, the study [52] describes a theory of percolation and interfacial characterisation via breakdown voltage measurement.…”

Section: Improvement Of Epoxy Based Composites Insulating Propertiesmentioning

confidence: 91%

Magnesium Oxide Nanoparticles: Dielectric Properties, Surface Functionalization and Improvement of Epoxy-Based Composites Insulating Properties

et al. 2018

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Composite insulation materials are an inseparable part of numerous electrical devices because of synergy effect between their individual parts. One of the main aims of the presented study is an introduction of the dielectric properties of nanoscale magnesium oxide powder via Broadband Dielectric Spectroscopy (BDS). These unique results present the behavior of relative permittivity and loss factor in frequency and temperature range. Following the current trends in the application of inorganic nanofillers, this article is complemented by the study of dielectric properties (dielectric strength, volume resistivity, dissipation factor and relative permittivity) of epoxy-based composites depending on the filler amount (0, 0.5, 0.75, 1 and 1.25 weight percent). These parameters are the most important for the design and development of the insulation systems. The X-ray diffraction patterns are presented for pure resin and resin with optimal filler amount (1 wt %), which was estimated according to measurement results. Magnesium oxide nanoparticles were also treated by addition of silane coupling agent (γ-Glycidoxypropyltrimethoxysilane), in the case of optimal filler loading (1 wt %) as well. Besides previously mentioned parameters, the effects of surface functionalization have been observed by two unique measurement and evaluation techniques which have never been used for this evaluation, i.e., reduced resorption curves (RRCs) and voltage response method (VR). These methods (developed in our departments), extend the possibilities of measurement of composite dielectric responses related to DC voltage application, allow the facile comparability of different materials and could be used for dispersion level evaluation. This fact has been confirmed by X-ray diffraction analyses.

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Section: Improvement Of Epoxy Based Composites Insulating Propertiesmentioning

confidence: 91%

Magnesium Oxide Nanoparticles: Dielectric Properties, Surface Functionalization and Improvement of Epoxy-Based Composites Insulating Properties

et al. 2018

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“…In the case of nanofluids' applications in transformers, the main research is related to the improvement of the dielectric properties of the base liquids. There are many publications confirming the positive influence of electro-insulating liquids' modifications, with nanomaterials on their dielectric properties and phenomena such as breakdown voltage [40][41][42][43], streamer propagation [44], electrical conductivity, and the dissipation factor [45][46][47][48][49]. In addition, as reported in the literature [50,51], fullerene C 60 can also be used to absorb free radicals arising from the aging of vegetable oils.…”

Section: Introductionmentioning

confidence: 88%

“…Analyzing the calculated temperature decreases, it can be concluded that the modification of electro-insulating liquids with surfactant Span ® 20 and titanium dioxide TiO 2 nanoparticles does not significantly affect the heat transport in the obtained nanofluids. Bearing in mind that these nanoparticles are mainly used to improve dielectric properties [41,46,49], it can be concluded that they will not cause deterioration in the cooling efficiency of the device.…”

Section: Kind Of Liquidmentioning

confidence: 99%

Effects of Nanoparticles Materials on Heat Transfer in Electro-Insulating Liquids

2018

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This paper discusses the effect of doping of electro-insulating liquids with nanoparticle materials on the thermal properties of the obtained nanoliquids and heat transport in the transformer. Mineral oil, synthetic ester, and natural ester were used as base liquids. The effectiveness of doping base liquids with nanoparticles was supported by ultraviolet-visible (UV/VIS) measurements. In turn, Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) confirmed the absence of intermolecular interactions (i.e., hydrogen bonding). The influence of modification of electro-insulating liquids with fullerene C60 and titanium dioxide TiO2 nanoparticles on such thermal properties as thermal conductivity, specific heat, kinematic viscosity, density, and thermal expansion was investigated. Based on these properties and the theory of similarity, the cooling efficiency of the transformer filled with the analyzed nanofluids was determined. Nanofluids’ cooling effectiveness was compared with the cooling effectiveness of the base liquids. This comparison was supported by an analysis of Grashof, Prandtl, and Nusselt numbers. It has been shown that the modification of electro-insulating liquids with nanoparticles widely used in order to improve their dielectric properties, such as C60 and TiO2, does not have a significant influence on their thermal properties. The addition of fullerene C60 caused an increase in kinematic viscosity, which was compensated by the increase in specific heat. In the case of TiO2, the addition of this nanoparticle resulted in an increase in kinematic viscosity and a decrease in specific heat, which were balanced out by the increase in thermal conductivity. In summary, the heat exchange-capacity of liquids did not change due to doping with nanoparticles.

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Section: A Review Of the Special Issuementioning

confidence: 99%

“…Articles [2,3] are in the lines of modifying the properties of insulating fluids using suitable nanoparticles. In [2], an attempt has been made by Mentlik et al to improve the properties of the natural ester available in the Central European region that is a rapeseed (Brassica napus seed) oil. Authors tried to modify the properties of natural esters through percolation treatment and oxidation inhibition by a phenolic-type inhibitor and further using titanium dioxide (TiO 2 ) nanoparticles with a silica surface treatment.…”

Section: A Review Of the Special Issuementioning

confidence: 99%

Engineering Dielectric Liquid Applications

Fofana

Rao

2018

Energies

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Development of a Biodegradable Electro-Insulating Liquid and Its Subsequent Modification by Nanoparticles

Cited by 35 publications

References 35 publications

Magnesium Oxide Nanoparticles: Dielectric Properties, Surface Functionalization and Improvement of Epoxy-Based Composites Insulating Properties

Magnesium Oxide Nanoparticles: Dielectric Properties, Surface Functionalization and Improvement of Epoxy-Based Composites Insulating Properties

Effects of Nanoparticles Materials on Heat Transfer in Electro-Insulating Liquids

Engineering Dielectric Liquid Applications

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