AC and Negative Lightning Impulse Breakdown Voltage of Mineral Oil with Different Nitrogen Addition Treatment Methods

2020 ◽  
Vol 140 (9) ◽  
pp. 473-478
Author(s):  
Norimitsu Takamura ◽  
Nobutaka Araoka ◽  
Tomohiro Tsutsumi ◽  
Masahiro Hanai
Keyword(s):  
Breakdown Voltage ◽  
Nitrogen Addition ◽  
Mineral Oil ◽  
Treatment Methods ◽  
Lightning Impulse

Negative Lightning Impulse Breakdown Characteristics of Mineral Oil with Different Nitrogen Addition Treatment Methods using Rogowski Electrodes

2021 ◽  
Vol 141 (7) ◽  
pp. 435-442
Author(s):  
Norimitsu Takamura ◽  
Nobutaka Araoka ◽  
Tomohiro Tsutsumi ◽  
Masahiro Fujimura ◽  
Masahiro Hanai
Keyword(s):  
Nitrogen Addition ◽  
Mineral Oil ◽  
Treatment Methods ◽  
Lightning Impulse

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.

scholarly journals Behavior of Biodegradable Oil under Impulse Voltages

2015 ◽  
Vol 785 ◽  
pp. 320-324 ◽  
Author(s):  
Nurul Izzatul Akma Katim ◽  
Mohd Taufiq Ishak ◽  
A.M. Ishak ◽  
M.Z.A.A. Kadir
Keyword(s):  
Breakdown Voltage ◽  
Palm Oil ◽  
Coconut Oil ◽  
Mineral Oil ◽  
Electrical Performance ◽  
Uniform Field ◽  
Testing Methods ◽  
Environmental Compatibility ◽  
Impulse Voltage ◽  
Lightning Impulse

The properties of Palm Oil (PO) and Coconut Oil (CO) offer the potential for transformers with non-toxicity, high fire and flash points and better environmental compatibility while compared with those filled with Mineral Oil (MO). This potential has led to intensive studies of electrical performance of biodegradable oil especially in evaluating the electrical performance under lightning impulse voltage in recent years. This paper presents the investigation on the impulse breakdown voltage of PO and CO in such a uniform field. The PO used in this study is Refined, Bleached and Deodorized Palm Oil (RBDPO) Olein type. Two testing methods, rising-voltage and up-and-down are considered for both oils with different gap distances (2.0 mm and 3.8 mm). Testing methods including rising-voltage method and up-and-down method have no notable influence on the breakdown voltages of RBDPOs and CO compared to MO.

Analysis of Dissolved Nitrogen and Oxygen Gas Amounts in Mineral Oil with Different Nitrogen Addition Treatment Methods

2020 ◽  
Vol 140 (11) ◽  
pp. 534-539
Author(s):  
Norimitsu Takamura ◽  
Nobutaka Araoka ◽  
Tomohiro Tsutsumi ◽  
Masahiro Hanai
Keyword(s):  
Nitrogen Addition ◽  
Mineral Oil ◽  
Treatment Methods ◽  
Dissolved Nitrogen ◽  
Oxygen Gas

scholarly journals Lightning Impulse Withstand of Natural Ester Liquid

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1964 ◽  
Author(s):  
Stephanie Haegele ◽  
Farzaneh Vahidi ◽  
Stefan Tenbohlen ◽  
Kevin Rapp ◽  
Alan Sbravati
Keyword(s):  
Breakdown Voltage ◽  
Dielectric Strength ◽  
Mineral Oil ◽  
Homogeneous Field ◽  
Inhomogeneous Field ◽  
Insulating Liquids ◽  
Lightning Impulse ◽  
Insulating Liquid ◽  
Natural Ester ◽  
Inhomogeneity Factor

Due to the low biodegradability of mineral oil, intense research is conducted to define alternative liquids with comparable dielectric properties. Natural ester liquids are an alternative in focus; they are used increasingly as insulating liquid in distribution and power transformers. The main advantages of natural ester liquids compared to mineral oil are their good biodegradability and mainly high flash and fire points providing better fire safety. The dielectric strength of natural ester liquids is comparable to conventional mineral oil for homogeneous field arrangements. However, many studies showed a reduced dielectric strength for highly inhomogeneous field arrangements. This study investigates at which degree of inhomogeneity differences in breakdown voltage between the two insulating liquids occur. Investigations use lightning impulses with different electrode arrangements representing different field inhomogeneity factors and different gap distances. To ensure comparisons with existing transformer geometries, investigations are application-oriented using a transformer conductor model, which is compared to other studies. Results show significant differences in breakdown voltage from an inhomogeneity factor of 0.1 (highly inhomogeneous field) depending on the gap distance. Larger electrode gaps provide a larger inhomogeneity at which differences in breakdown voltages occur.

scholarly journals Investigation of the Lightning Impulse Breakdown Voltage of Mineral Oil based Fe3O4 Nanofluids

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 799 ◽  
Author(s):  
Víctor A. Primo ◽  
Belén García ◽  
Juan Carlos Burgos ◽  
Daniel Pérez-Rosa
Keyword(s):  
Dielectric Properties ◽  
Breakdown Voltage ◽  
Mineral Oil ◽  
Power Transformers ◽  
Experimental Conditions ◽  
Insulating Materials ◽  
Recent Interest ◽  
Insulating Liquids ◽  
Lightning Impulse ◽  
Transformer Design

The recent interest in the development of nanomaterials has led researchers to the study of their electrical properties and the applications that they may have as insulating materials. One of these applications is the use of nanofluids as electrical insulation of power transformers. It has been reported that the dielectric properties of insulating liquids in which small amounts of nanoparticles have been dispersed are, in some cases, superior to those of the base fluids. Although these materials are promising, and their application could lead to advantages for the transformer design and reliability in the future, more research is necessary to evaluate different combination of materials under a wider range of experimental conditions. In this paper, a research on the lightning impulse breakdown voltage of mineral oil and several Fe3O4-based nanofluids is presented. Fluids prepared with different concentrations of nanoparticles were subjected to impulse lightning voltages considering both positive and negative polarities. As shown in this work the positive impulse breakdown voltage of the liquids showed improvements of up to 50%; in the case of the negative impulses not significant improvements were obtained.

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.

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