scholarly journals Statistical Investigation of Lightning Impulse Breakdown Voltage of Natural and Synthetic Ester Oils-Based Fe3O4, Al2O3 and SiO2 Nanofluids

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 112615-112623 ◽  
Author(s):  
Abderrahmane Beroual ◽  
Usama Khaled
Keyword(s):  
Breakdown Voltage ◽  
Statistical Investigation ◽  
Synthetic Ester ◽  
Lightning Impulse ◽  
Natural And Synthetic

scholarly journals Influence of Molecule Structure on Lightning Impulse Breakdown of Ester Liquids

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1061
Author(s):  
Huaqiang Li ◽  
Linfeng Xia ◽  
Shengwei Cai ◽  
Zhiqiang Huang ◽  
Jiaqi Li ◽  
...  
Keyword(s):  
Electric Fields ◽  
Breakdown Voltage ◽  
Experimental Research ◽  
Environmentally Friendly ◽  
Mineral Oil ◽  
Positive Polarity ◽  
Mineral Oils ◽  
Synthetic Ester ◽  
Lightning Impulse ◽  
Natural Ester

Ester liquids are environmentally friendly insulating oils, and they can be used as an alternative to mineral oil in transformers, even though in most countries spills of ester oils must be treated like spills of mineral oil. Furthermore, the breakdown characteristics of ester liquids are worse than those of mineral oils in heterogeneous electric fields. In this paper, we present a comprehensive experimental research on both positive and negative lightning impulse breakdown properties in point-plane geometries with gaps varying from 1 mm to 50 mm. The breakdown voltages and streamer velocities of five kinds of ester liquids, including natural ester, synthetic ester, and three kinds of single component esters have been measured. The results show that the double bonds have no effect on the breakdown voltage of ester liquids. The average streamer velocities of mono-esters are faster than that of other esters under positive polarity, and the breakdown voltages of all esters are close.

Characteristics of Negative Lightning Impulse Breakdown Voltage in Pure Water

2018 ◽  
Vol 138 (8) ◽  
pp. 441-448 ◽  
Author(s):  
Norimitsu Takamura ◽  
Nobutaka Araoka ◽  
Seiya Kamohara ◽  
Yuta Hino ◽  
Takuya Beppu ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Pure Water ◽  
Lightning Impulse

Electrophysical properties of mixtures of mineral oil and synthetic ester dielectric liquid

2021 ◽  
Vol 14 (2) ◽  
pp. 132-141
Author(s):  
M. N. Lyutikova ◽  
S. M. Korobeynikov ◽  
A. A. Konovalov
Keyword(s):  
Dielectric Loss ◽  
Breakdown Voltage ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Kinematic Viscosity ◽  
Mineral Oil ◽  
Flash Point ◽  
Power Transformers ◽  
Synthetic Ester ◽  
Insulating Properties

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.

scholarly journals Lightning Impulse Breakdown Voltage of Rice Bran Oil for Transformer Application

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5084
Author(s):  
Mardhiah Hayati Abdul Hamid ◽  
Mohd Taufiq Ishak ◽  
Nur Sabrina Suhaimi ◽  
Jaafar Adnan ◽  
Nazrul Fariq Makmor ◽  
...  
Keyword(s):  
Weibull Distribution ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
Rice Bran ◽  
Rice Bran Oil ◽  
Transformer Oil ◽  
Uniform Field ◽  
Testing Methods ◽  
Lightning Impulse ◽  
The Difference

Transformer oil does not only serve as an insulating liquid, but also in removing heat from the windings and cores. Mineral oil (MO) has been widely used in transformers for more than 150 years. Recently, researchers have attempted to search for alternative insulating oils due to the possibility that MO will run out in the future together with the concern on fire safety and environmental pollution. Among the potential oils is rice bran oil (RBO). This work presents the studies of the lightning impulse (LI) of RBO behavior under various electric fields, gap distances and testing methods. The electrical performances of LI tests show that RBO and Palm Oil (PO) have lower LI breakdown voltage than MO under both uniform and non-uniform electric fields. However, the difference in LI breakdown voltages between RBO, PO and MO are slightly small which is less than 20%. In addition, there is no significant effect in the various testing methods under both uniform field and non-uniform field where the percentages of difference are less than 12% and 8% respectively. The data of LI breakdown voltage were statistically analysed to predict the withstand voltage and 50% breakdown voltage of oil samples by using Weibull distribution. The Weibull distribution of MO, PO and RBO has well fit with the fitting line. Finally, the relationship between LI voltages under a non-uniform field with various parameters of PO and RBO was obtained and proposed. From this work, it can be concluded that RBO shows promising results to be considered as an alternative to MO in transformer applications.

scholarly journals The Impact of TiO2 Nanoparticle Concentration Levels on Impulse Breakdown Performance of Mineral Oil-Based Nanofluids

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 627 ◽  
Author(s):  
Ziyi Wang ◽  
You Zhou ◽  
Wu Lu ◽  
Neng Peng ◽  
Weijie Chen
Keyword(s):  
Tio2 Nanoparticles ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
Concentration Level ◽  
Breakdown Strength ◽  
Mineral Oil ◽  
Interfacial Region ◽  
Bulk Oil ◽  
Lightning Impulse ◽  
The Impact

The insulation of mineral oil-based nanofluids was found to vary with different concentration level of nanoparticles. However, the mechanisms behind this research finding are not well studied. In this paper, mineral oil-based nanofluids were prepared by suspending TiO2 nanoparticles with weight percentages ranging from 0.0057% to 0.0681%. The breakdown voltage and chop time of nanofluids were observed under standard lightning impulse waveform. The experimental results show that the presence of TiO2 nanoparticles increases the breakdown voltage of mineral oil under positive polarity. The enhancement of breakdown strength tends to saturate when the concentration of nanoparticle exceeds 0.0227 wt%. Electronic traps formed at the interfacial region of nanoparticles, which could capture fast electrons in bulk oil and reduce the net density of space charge in front of prebreakdown streamers, are responsible for the breakdown strength enhancement. When the particle concentration level is higher, the overlap of Gouy–Chapman diffusion layers results in the saturation of trap density in nanofluids. Consequently, the breakdown strength of nanofluids is saturated. Under negative polarity, the electrons are likely to be scattered by the nanoparticles on the way towards the anode, resulting in enhanced electric fields near the streamer tip and the decrement of breakdown voltage.

Sign in / Sign up

Export Citation Format

Share Document