scholarly journals Experimental Studies on Thermophysical and Electrical Properties of Graphene–Transformer Oil Nanofluid

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 172
Author(s):  
Charishma Almeida ◽  
Sohan Paul ◽  
Lazarus Godson Asirvatham ◽  
Stephen Manova ◽  
Rajesh Nimmagadda ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Surface Tension ◽  
Electrical Properties ◽  
Maximum Concentration ◽  
Distribution Systems ◽  
Power Transmission ◽  
Specific Resistance ◽  
Experimental Studies ◽  
Transformer Oil ◽  
Weight Percentage

The thermophysical and electrical properties of graphene–transformer oil nanofluid at three weight percentage concentrations (0.01%, 0.03%, and 0.05%) were experimentally studied. Experiments conducted to find viscosity, surface tension, density, specific resistance, electrical conductivity, and dielectric dissipation at various temperatures ranging from 20 °C to 90 °C. It was noted that the nanofluid with 0.05% concentration showed an enhancement of 2.5% and 16.6% for density and viscosity, respectively, when compared to transformer oil. In addition, an average reduction in surface tension is noted to be 10.1% for the maximum concentration of nanofluid. Increase in heat load and concentration improves Brownian motion and decreases the cohesive force between these particles, which results in a reduction in surface tension and increases the heat-transfer rate compared to transformer oil. In addition, for the maximum concentration of nanoparticles, the electrical conductivity of nanofluid was observed to be 3.76 times higher than that of the transformer oil at 90 °C. The addition of nanoparticles in the transformer oil decreases the specific resistance and improves the electrical conductivity thereby enhancing the breakdown voltage. Moreover, the thermophysics responsible for the improvement in thermophysical and electrical properties are discussed clearly, which will be highly useful for the design of power transmission/distribution systems.

scholarly journals Modifications of the SURDAT database of the physicochemical properties of metals and alloys

2012 ◽  
Vol 48 (3) ◽  
pp. 427-431 ◽  
Author(s):  
W. Gasior ◽  
A. Debski
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Electrical Properties ◽  
Experimental Studies ◽  
Viscosity Data ◽  
Pressure Method ◽  
Mechanical And Electrical Properties ◽  
Study Results ◽  
Wetting Time ◽  
Wetting Force

Experimental studies of the surface tension and the density were carried out by means of the maximum bubble pressure method and the dilatometric technique and next, they were compiled with the results of over 12 years of research of the liquid pure components, binary and multicomponent alloys, with the aim to create the SURDAT database of the Pb-free soldering materials. In the last years, a modification of SURDAT has been conducted. The new version, beside the earlier data of the physical properties, also contains such data as: the viscosity data, selected data of the mechanical and electrical properties, the DTA data and the meniscographic study results (contact angle, wetting time, wetting force and interfacial tension). Additionally, the data base of the heat properties, worked out at NIST (National Institute of Standard and Technology from Boulder in Colorado) has been implemented.

scholarly journals On the High Frequency Response of Grounding Electrodes: Effect of Soil Dielectric Constant

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
behzad kordi
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Transmission Lines ◽  
High Frequency ◽  
Relative Permittivity ◽  
Distribution Systems ◽  
Power Transmission ◽  
Geographical Location ◽  
Lightning Strike ◽  
Accurate Estimation

<div><b>"This paper is a postprint of a paper submitted to and accepted for publication in IET Generation, Transmission & Distibution (GTD) and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at the IET Digital Library."</b></div><div><b><br></b></div><div><b>Abstract:</b><br></div><div>Grounding electrodes have an important role in electric power transmission and distribution systems. They are used to prevent excessive hazardous voltages between metallic structures and ground in the case of system faults or lightning surges. It is important that they provide a low impedance path for the current in to the ground. The electrical properties of soil, which vary substantially with geographical location and time of year, affect the process considerably along with the properties of the grounding electrode itself, such as its dimensions.</div>In order to have an accurate estimation of the developed overvoltages and the backflashover rate of the transmission lines due to a lightning strike, one has to take into account the effect of the value of the soil electrical parameters, such as the electrical conductivity and dielectric constant.<br>This paper investigates the high frequency behavior of the grounding electrodes by solving a full-wave electromagnetic problem using the Finite Element Method (FEM). The focus is on taking into account the effect of the variation of soil relative permittivity which has been neglected in the previous studies of the grounding systems. This allows an evaluation of the response of grounding systems due to seasonal changes and specifically change of the water content of the soil, which would cause its electrical properties to vary significantly. This study<br>demonstrates the importance of considering the variation of relative permittivity of the soil especially in the modeling of electrodes buried in highly resistive soil.<br>

scholarly journals High frequency response of grounding electrodes: effect of soil dielectric constant

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
behzad kordi
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Transmission Lines ◽  
High Frequency ◽  
Relative Permittivity ◽  
Distribution Systems ◽  
Power Transmission ◽  
Geographical Location ◽  
Lightning Strike ◽  
Accurate Estimation

<div><b>"This paper is a postprint of a paper submitted to and accepted for publication in IET Generation, Transmission & Distibution (GTD) and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at the IET Digital Library."</b></div><div><b><br></b></div><div><b>Abstract:</b><br></div><div>Grounding electrodes have an important role in electric power transmission and distribution systems. They are used to prevent excessive hazardous voltages between metallic structures and ground in the case of system faults or lightning surges. It is important that they provide a low impedance path for the current in to the ground. The electrical properties of soil, which vary substantially with geographical location and time of year, affect the process considerably along with the properties of the grounding electrode itself, such as its dimensions.</div>In order to have an accurate estimation of the developed overvoltages and the backflashover rate of the transmission lines due to a lightning strike, one has to take into account the effect of the value of the soil electrical parameters, such as the electrical conductivity and dielectric constant.<br>This paper investigates the high frequency behavior of the grounding electrodes by solving a full-wave electromagnetic problem using the Finite Element Method (FEM). The focus is on taking into account the effect of the variation of soil relative permittivity which has been neglected in the previous studies of the grounding systems. This allows an evaluation of the response of grounding systems due to seasonal changes and specifically change of the water content of the soil, which would cause its electrical properties to vary significantly. This study<br>demonstrates the importance of considering the variation of relative permittivity of the soil especially in the modeling of electrodes buried in highly resistive soil.<br>

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

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 269
Author(s):  
Konstantinos N. Koutras ◽  
Sokratis N. Tegopoulos ◽  
Vasilios P. Charalampakos ◽  
Apostolos Kyritsis ◽  
Ioannis F. Gonos ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Spectroscopy ◽  
Partial Discharge ◽  
Transformer Oil ◽  
Spectroscopy Technique ◽  
Sic Nanoparticles ◽  
Base Oil ◽  
Weight Percentage ◽  
Broadband Dielectric Spectroscopy

In this work, the influence of semi-conductive SiC nanoparticles on the AC breakdown voltage and partial discharge development in natural ester oil FR3 is examined. Primarily, the dielectric constant and the electrical conductivity of the nanoparticles are measured following the broadband dielectric spectroscopy technique. The nanoparticles are added into the matrix following the ultrasonication process in three weight percentage ratios in order for their effect to be evaluated as a function of their concentration inside the base oil. The processing of the results reveals that the nanofluid containing SiC nanoparticles at 0.004% w/w demonstrates the highest AC dielectric strength improvement and shows the greatest resistance to the appearance of partial discharge activity. The mechanisms behind the aforementioned results are discussed in detail and confirmed by the broadband dielectric spectroscopy technique, which reveals that this particular nanofluid sample is characterized by lower dielectric constant and electrical conductivity than the one with double the weight percentage ratio.

scholarly journals High frequency response of grounding electrodes: effect of soil dielectric constant

2020 ◽  
Author(s):  
Bamdad Salarieh ◽  
H. M. Jeewantha De Silva ◽  
behzad kordi
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Transmission Lines ◽  
High Frequency ◽  
Relative Permittivity ◽  
Distribution Systems ◽  
Power Transmission ◽  
Geographical Location ◽  
Lightning Strike ◽  
Accurate Estimation

<div><b>"This paper is a postprint of a paper submitted to and accepted for publication in IET Generation, Transmission & Distibution (GTD) and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at the IET Digital Library."</b></div><div><b><br></b></div><div><b>Abstract:</b><br></div><div>Grounding electrodes have an important role in electric power transmission and distribution systems. They are used to prevent excessive hazardous voltages between metallic structures and ground in the case of system faults or lightning surges. It is important that they provide a low impedance path for the current in to the ground. The electrical properties of soil, which vary substantially with geographical location and time of year, affect the process considerably along with the properties of the grounding electrode itself, such as its dimensions.</div>In order to have an accurate estimation of the developed overvoltages and the backflashover rate of the transmission lines due to a lightning strike, one has to take into account the effect of the value of the soil electrical parameters, such as the electrical conductivity and dielectric constant.<br>This paper investigates the high frequency behavior of the grounding electrodes by solving a full-wave electromagnetic problem using the Finite Element Method (FEM). The focus is on taking into account the effect of the variation of soil relative permittivity which has been neglected in the previous studies of the grounding systems. This allows an evaluation of the response of grounding systems due to seasonal changes and specifically change of the water content of the soil, which would cause its electrical properties to vary significantly. This study<br>demonstrates the importance of considering the variation of relative permittivity of the soil especially in the modeling of electrodes buried in highly resistive soil.<br>

Effect of Gamma Radiation on Structural, Optical and Electrical Properties of nanostructured CdHgTe Thin Films

2018 ◽  
Vol 1 (1) ◽  
pp. 26-31 ◽  
Author(s):  
B Babu ◽  
K Mohanraj ◽  
S Chandrasekar ◽  
N Senthil Kumar ◽  
B Mohanbabu
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Gamma Radiation ◽  
Glass Substrate ◽  
Gamma Ray ◽  
Optical And Electrical Properties ◽  
Deposition Technique ◽  
Polycrystalline Structure ◽  
Dc Electrical Conductivity

CdHgTe thin films were grown onto glass substrate via the Chemical bath deposition technique. XRD results indicate that a CdHgTe formed with a cubic polycrystalline structure. The crystallinity of CdHgTe thin films is gradually deteriorate with increasing the gamma irradiation. EDS spectrums confirms the presence of Cd, Hg and Te elements. DC electrical conductivity results depicted the conductivity of CdHgTe increase with increasing a gamma ray dosage

Effect of the structure of cellulose acetate membranes on their permeability, electrical conductivity and rejection

1990 ◽  
Vol 55 (12) ◽  
pp. 2933-2939 ◽  
Author(s):  
Hans-Hartmut Schwarz ◽  
Vlastimil Kůdela ◽  
Klaus Richau
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Cellulose Acetate ◽  
Reverse Osmosis ◽  
Water Flux ◽  
Cellulose Acetate Membrane ◽  
Structure Parameters ◽  
Dc Electrical Conductivity ◽  
Cellulose Acetate Membranes

Ultrafiltration cellulose acetate membrane can be transformed by annealing into reverse osmosis membranes (RO type). Annealing brings about changes in structural properties of the membranes, accompanied by changes in their permeability behaviour and electrical properties. Correlations between structure parameters and electrochemical properties are shown for the temperature range 20-90 °C. Relations have been derived which explain the role played by the dc electrical conductivity in the characterization of rejection ability of the membranes in the reverse osmosis, i.e. rRO = (1 + exp (A-B))-1, where exp A and exp B are statistically significant correlation functions of electrical conductivity and salt permeation, or of electrical conductivity and water flux through the membrane, respectively.

Enhanced electrical conductivity of Au–LaNiO3 nanocomposite thin films by chemical solution deposition

RSC Advances ◽  
2015 ◽  
Vol 5 (94) ◽  
pp. 76783-76787 ◽  
Author(s):  
H. L. Wang ◽  
X. K. Ning ◽  
Z. J. Wang
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Chemical Solution Deposition ◽  
Nanocomposite Films ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Nanocomposite Thin Films ◽  
One Step

Au–LaNiO3 (Au–LNO) nanocomposite films with 3.84 at% Au were firstly fabricated by one-step chemical solution deposition (CSD), and their electrical properties were investigated.

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