scholarly journals Comparative Study of Breakdown Voltage of Mineral, Synthetic and Natural Oils and Based Mineral Oil Mixtures under AC and DC Voltages

Energies ◽  
2017 ◽  
Vol 10 (4) ◽  
pp. 511 ◽  
Author(s):  
Abderrahmane Beroual ◽  
Usama Khaled ◽  
Phanuel Mbolo Noah ◽  
Henry Sitorus
Keyword(s):  
Comparative Study ◽  
Breakdown Voltage ◽  
Mineral Oil ◽  
Natural Oils ◽  
Oil Mixtures

scholarly journals Comparative Study on the Thermal-Aging Characteristics of Cellulose Insulation Polymer Immersed in New Three-Element Mixed Oil and Mineral Oil

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1292 ◽  
Author(s):  
Dawei Feng ◽  
Jian Hao ◽  
Ruijin Liao ◽  
Xin Chen ◽  
Lin Cheng ◽  
...  
Keyword(s):  
Comparative Study ◽  
Breakdown Voltage ◽  
Thermal Aging ◽  
Cellulose Degradation ◽  
Mineral Oil ◽  
Aging Rate ◽  
Cellulose Paper ◽  
Paper Insulation ◽  
Cellulose Insulation ◽  
Insulation Oil

Cellulose paper, whose main component is cellulose polymer, has been widely used in oil-immersed power transformer that gradually deteriorates during transformer operation. Thermal aging is the main degradation form for cellulose paper immersed in insulation oil (oil–paper insulation) in a transformer. One of the most challenging issues in oil–paper insulation is inhibiting the aging of cellulose paper and extending its life. In this work, a comparative study was conducted on the thermal-aging characteristics of cellulose paper immersed in a novel three-element mixed insulation oil and mineral oil at 130 °C for 150 days. The key parameters of cellulose paper were analysed, including the degree of polymerization (DP), thermal-aging rate, surface colour, and AC breakdown voltage. The furfural content and acidity of the oil, as well as the AC breakdown voltage of the insulation oil were also analysed. The results show that the cellulose paper immersed in novel three-element mixed insulation oil had much higher DP values than that immersed in mineral oil after the same thermal-aging time. The mixed insulation oil could significantly inhibit the thermal aging of cellulose paper and prolong its life. The thermal-aging rate of the cellulose insulation polymer immersed in mixed insulation oil is significantly lower than that immersed in mineral oil, whether in the process of oil–paper insulation continuous aging or in the process of aging after oil replacement with unused insulation oil. The furfural generated by cellulose degradation in the novel three-element mixed insulation oil was also less than that in the mineral oil. The mixed insulation oil had a higher acidity value during the thermal-aging process, which was mainly due to the natural esters in the components of the mixed insulation oil. However, the AC breakdown voltage of the mixed insulation oil was always higher than that of the mineral oil. This study offers a new perspective in inhibiting the thermal aging of cellulose polymer in insulation oil.

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.

Effect of Water on Electrical Properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as Electrical Insulating Material

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Nazera Ismail ◽  
Yanuar Z. Arief ◽  
Zuraimy Adzis ◽  
Shakira A. Azli ◽  
Abdul Azim A. Jamil ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Pour Point ◽  
Electrical Breakdown ◽  
Dissipation Factor ◽  
Mineral Oil ◽  
Flash Point ◽  
Effect Of Water ◽  
Insulating Liquid

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water.

scholarly journals Effect of electrical discharge on the properties of natural esters insulating fluids

2021 ◽  
Vol 23 (3) ◽  
pp. 1281
Author(s):  
Imran Sutan Chairul ◽  
Sharin Ab Ghani ◽  
Nur Hakimah Ab Aziz ◽  
Mohd Shahril Ahmad Khiar ◽  
Muhammad Syahrani Johal ◽  
...  
Keyword(s):  
Water Content ◽  
Breakdown Voltage ◽  
Electrical Discharge ◽  
Mineral Oil ◽  
Electrical Discharges ◽  
Inhomogeneous Electric Field ◽  
Sustainable Resources ◽  
Low Viscosity ◽  
Environmental Friendly ◽  
Natural Ester

<p>Vegetable oils have been an alternative to mineral oil for oil-immersed transformers due to concern on less flammable, environmental-friendly, biodegradable, and sustainable resources of petroleum-based insulating oil. This paper presents the effect of electrical discharges (200 up to 1000 discharges) under 50 Hz inhomogeneous electric field on the properties (acidity, water content, and breakdown voltage) of two varieties of vegetable based insulating oils; i) natural ester (NE) and ii) low viscosity insulating fluids derived from a natural ester (NE<sub>LV</sub>). Results show the water content, acidity and breakdown voltage of NE fluctuate due to applied discharges, while NE<sub>LV</sub> display insignificant changes. Hence, results indicate that the low viscosity insulating fluids derived from natural ester tend to maintain their properties compared to natural ester.</p>

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.

Comparative Study of Lighting Impulse Properties for Mineral Oil and Ester Liquids

2019 ◽  
Author(s):  
Cai Shengwei ◽  
Xia Linfeng ◽  
Huang Zhiqiang ◽  
Li Huaqiang ◽  
Zhong Lisheng ◽  
...  
Keyword(s):  
Comparative Study ◽  
Mineral Oil
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