scholarly journals Effect of repeated electrical breakdowns on mineral and natural ester insulating oils

2021 ◽  
Vol 10 (6) ◽  
pp. 2989-2996
Author(s):  
Sharin Ab Ghani ◽  
Mohd Shahril Ahmad Khiar ◽  
Imran Sutan Chairul ◽  
Muhammad Imran Zamir
Keyword(s):  
Breakdown Voltage ◽  
Electrical Discharge ◽  
Electrical Breakdown ◽  
Standard Test ◽  
Test Method ◽  
Power Transformers ◽  
Insulating Oil ◽  
Different Types ◽  
Increasing Demand ◽  
Natural Ester

Transformer insulating oils are exposed to repeated electrical discharge or breakdowns inside power transformers. Durability tests are conducted to analyze the ability of oil to resist decomposition due to such high electrical stresses. With the increasing demand for alternative insulating oils for oil-immersed transformers, it is worthy to compare the performance of different types of insulating oils (conventional mineral-based insulating oil and natural ester-based insulating oil) under repeated electrical breakdown. In this paper, the AC breakdown voltage of different mineral-based and natural ester-based insulating oils is reported. Durability tests were conducted based on the AC breakdown voltage behavior of insulating oils after 50 electrical breakdown shots. The AC breakdown voltage of each insulating oil sample was assessed according to the ASTM D1816 standard test method. Based on the results, it can be concluded that the dissimilarity in chemical composition of the insulating oils has a significant effect on the AC breakdown voltage behavior of these oils under repeated electrical breakdowns.

Electrical Breakdown Voltage of Palm Oil and Nano Graphene Filler in Nanofluids Application on Transformer Insulating Oil

2021 ◽  
Vol 902 ◽  
pp. 59-63
Author(s):  
Kanin Wajanasoonthon ◽  
Amnart Suksri
Keyword(s):  
Breakdown Voltage ◽  
Palm Oil ◽  
Electrical Breakdown ◽  
High Viscosity ◽  
Mineral Oil ◽  
Power Transformers ◽  
Environment Friendly ◽  
Insulating Oil ◽  
Graphene Nanoparticles ◽  
Nano Graphene

Generally, power transformers have been using mineral oil as a liquid insulator due to its availability and excellent dielectric property. However, petroleum sources are depleting, which implies that mineral oil is going to be limited in availability. So, this research is to investigate on vegetable oil with nanographene filler as a substitution. Vegetable insulating oil is considered as environment-friendly insulating oil due to their superiority of biodegradable, nature-friendly, high fire-point, and good level of breakdown voltage (BV). Nevertheless, vegetable insulating oil have high viscosity, leading to a slow flow rate on the cooling performance of power transformers. To solve this problem, a process of transesterification was used to produce palm oil methyl ester (POME) from a refined bleached deodorized palm olein (RBDPO) to reduce its viscosity. RBDPO and POME were used as two kinds of fluid-based to combine with graphene nanoparticles (GNPs). Electrical breakdown voltage tests were performed by the IEC60156 standard. The results shown that POME have higher BV than RBDPO but adding GNPs may lead to lower BV even with a small amount of concentration. Nevertheless, every nanofluid has a higher BV than 30 kV.

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 Fabrication of Fe3O4@SiO2 Nanofluids with High Breakdown Voltage and Low Dielectric Loss

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 716
Author(s):  
Bin Du ◽  
Yu Shi ◽  
Qian Liu
Keyword(s):  
Dielectric Loss ◽  
Breakdown Voltage ◽  
Shell Thickness ◽  
Electrical Breakdown ◽  
Sio2 Nanoparticles ◽  
Electrical Equipment ◽  
Insulating Oil ◽  
Low Dielectric ◽  
Sio2 Shell ◽  
High Dielectric

Insulating oil modified by nanoparticle (often called nanofluids) has recently drawn considerable attention, especially concerning the improvement of electrical breakdown and thermal conductivity of the nanofluids. However, traditional insulating nanofluid often tends to high dielectric loss, which accelerates the ageing of nanofluids and limits its application in electrical equipment. In this paper, three core-shell Fe3O4@SiO2 nanoparticles with different SiO2 shell thickness were prepared and subsequently dispersed into insulating oil to achieve nanofluids. The dispersion stability, breakdown voltages and dielectric properties of these nanofluids were comparatively investigated. Experimental results show the alternating current (AC) and positive lightning breakdown voltage of nanofluids increased by 30.5% and 61%, respectively. Moreover, the SiO2 shell thickness of Fe3O4@SiO2 nanoparticle had significant effects on the dielectric loss of nanofluids.

scholarly journals Comparative Study on the AC Brekadown Voltage of Palm Fatty Acid Ester Insulation Oils Mixed With Iron Oxide Nanoparticles

2016 ◽  
Vol 6 (4) ◽  
pp. 1481
Author(s):  
Mohd Safwan Mohamad ◽  
Hidayat Zainuddin ◽  
Sharin Ab Ghani ◽  
Imran Sutan Chairul
Keyword(s):  
Fatty Acid ◽  
Iron Oxide ◽  
Breakdown Voltage ◽  
Fatty Acid Ester ◽  
Acid Ester ◽  
Volume Fraction ◽  
Oxidation Stability ◽  
Standard Test ◽  
Test Method ◽  
Mineral Oils

Mineral oils are are derived from petroleum which is a non-renewable and non-sustainable source, and therefore there is a critical need to develop alternative insulation oils for use in transformers.  Ester oils offer a number of benefits over mineral oils such as good biodegradability, high cooling stability, good oxidation stability and excellent insulation performance. Nowadays, nanotechnology has become one of the most important research fields in both the academia and industry and it has been shown in previous studies that nanoscale materials are beneficial for transformers. In this regard, the objective of this study is to compare the AC breakdown voltage of palm fatty acid ester (PFAE) oils mixed with iron oxide (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles. The PFAE-based nanofluids are prepared using two methods: (1) Method I (weight-based method whereby the concentration of the Fe<sub>3</sub>O<sub>4 </sub>nanoparticles is 0.01 g/l) and (2) Method II (volume-fraction method whereby the concentration of the Fe<sub>3</sub>O<sub>4 </sub>nanoparticles is 0.01, 0.02 and 0.03%). The AC breakdown voltage test is conducted on the PFAE-based nanofluids in accordance with the ASTM D1816 standard test method. Weibull statistical analysis is carried out to analyse the AC breakdown voltage of fresh PFAE oil and PFAE-based nanofluids. It is found that there is enhancement of the AC breakdown voltage for all PFAE-based nanofluids with the exception of with the exception of one sample prepared using Method II (0.01% Fe<sub>3</sub>O<sub>4 </sub>nanoparticles).

Comparative Study on the AC Brekadown Voltage of Palm Fatty Acid Ester Insulation Oils Mixed With Iron Oxide Nanoparticles

2016 ◽  
Vol 6 (4) ◽  
pp. 1481
Author(s):  
Mohd Safwan Mohamad ◽  
Hidayat Zainuddin ◽  
Sharin Ab Ghani ◽  
Imran Sutan Chairul
Keyword(s):  
Fatty Acid ◽  
Iron Oxide ◽  
Breakdown Voltage ◽  
Fatty Acid Ester ◽  
Acid Ester ◽  
Volume Fraction ◽  
Oxidation Stability ◽  
Standard Test ◽  
Test Method ◽  
Mineral Oils

Mineral oils are are derived from petroleum which is a non-renewable and non-sustainable source, and therefore there is a critical need to develop alternative insulation oils for use in transformers.  Ester oils offer a number of benefits over mineral oils such as good biodegradability, high cooling stability, good oxidation stability and excellent insulation performance. Nowadays, nanotechnology has become one of the most important research fields in both the academia and industry and it has been shown in previous studies that nanoscale materials are beneficial for transformers. In this regard, the objective of this study is to compare the AC breakdown voltage of palm fatty acid ester (PFAE) oils mixed with iron oxide (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles. The PFAE-based nanofluids are prepared using two methods: (1) Method I (weight-based method whereby the concentration of the Fe<sub>3</sub>O<sub>4 </sub>nanoparticles is 0.01 g/l) and (2) Method II (volume-fraction method whereby the concentration of the Fe<sub>3</sub>O<sub>4 </sub>nanoparticles is 0.01, 0.02 and 0.03%). The AC breakdown voltage test is conducted on the PFAE-based nanofluids in accordance with the ASTM D1816 standard test method. Weibull statistical analysis is carried out to analyse the AC breakdown voltage of fresh PFAE oil and PFAE-based nanofluids. It is found that there is enhancement of the AC breakdown voltage for all PFAE-based nanofluids with the exception of with the exception of one sample prepared using Method II (0.01% Fe<sub>3</sub>O<sub>4 </sub>nanoparticles).

scholarly journals Development of a Test Method to Evaluate Durability of Pavement Joints under Winter Conditions

2021 ◽  
Author(s):  
Conrad Babicz
Keyword(s):  
Visual Inspection ◽  
Strength Loss ◽  
Standard Test ◽  
Test Method ◽  
Concrete Slabs ◽  
Freezing And Thawing ◽  
Premature Failure ◽  
Different Types ◽  
Evaluation Techniques ◽  
Different Levels

In areas with cold winters, premature failure in concrete pavement joints is a frequent phenomenon, yet there is no standard test method for evaluating their durability. In this study, the effectiveness of several evaluation techniques for concrete joint durability were evaluated. Concrete slabs with saw cuts representing joints were made, and exposed to different freezing and thawing/ wetting cycles, and different salt solutions (NaCl, CaCl2, and MgCl2). The durability of the joints was evaluated using measures of strength loss, mass loss, and a visual inspection. It was found that under these exposure conditions, the strength loss and visual inspection modes of evaluation could discern different levels of damage between different types of exposures, and also different concrete mixes (e.g. Different cement contents, strength and the presence or absence of SCM). Further research is required to evaluate the effects of sealants, saturated bases, and higher salt concentrations.

Relating bending stiffness measurements across various free span lengths

TAPPI Journal ◽  
2020 ◽  
Vol 19 (8) ◽  
pp. 419-424
Author(s):  
DOUGLAS CASH ◽  
BENJAMIN FRANK
Keyword(s):  
Intrinsic Property ◽  
Standard Test ◽  
Bending Stiffness ◽  
Test Method ◽  
Corrugated Board ◽  
Different Types ◽  
Practical Tool ◽  
Bending Behavior ◽  
The Relationship ◽  
Corrugated Fiberboard

Bending stiffness should be an intrinsic property of a material, so it is puzzling that the TAPPI Standard Test Method T 836 “Bending stiffness, four point method” specifies span lengths when testing different types of corrugated fiberboard. These specified spans often limit the samples that can be measured with this method. To better understand the relationship between bending stiffness and span length, we performed measurements on a range of materials at different spans. The results provide a practical tool enabling comparison of bending stiff-ness measurements made at various span lengths. Additionally, this note discusses several areas that could serve as the foundation for more fundamental work exploring the bending behavior of corrugated board.

Determination of Resistance to Abrasive Wear. XI. Influence of the Type of Abrasive

1949 ◽  
Vol 22 (1) ◽  
pp. 268-276 ◽  
Author(s):  
R. G. Newton ◽  
J. R. Scott ◽  
W. H. Willott
Keyword(s):  
Comparative Method ◽  
Standard Test ◽  
Test Method ◽  
Large Area ◽  
Method Of Calculation ◽  
Different Types ◽  
Short Run ◽  
Two Sides ◽  
Abrasive Paper

Abstract Tests with the du Pont machine show that the practice of expressing abrasion test results as an abrasive index, i.e., abrasion-resistance relative to a standard rubber, does not enable different types of abrasive to be used indiscriminately because these are found to give widely different abrasive indices for the same rubber; thus, some abrasives may give four times as high an index as others. If attention is confined to abrasive papers, as distinct from bonded abrasive wheels, this variation is reduced, but is still large enough to be a serious factor in accurate work. It is clear that, even when this comparative method of testing is used, standardization of the abrasive paper is essential to reduce discrepancies between results obtained in different laboratories. Discrepancies will still exist, however, because abrasive paper is not uniform, and there is evidence that abrasive indices determined on different portions of the same paper may differ as much as those from different types of paper. To minimize the effect of this nonuniformity, two courses are open. (1) All the rubbers to be compared could be abraded on one and the same area of paper, preferably a large area to avoid wearing the surface, e.g., by giving each rubber a short run on each of the several paper discs used, instead of using a different disc for each rubber. (2) Different specimens could be tested on the two sides of the machine provided this has a pivotted arm. It is shown that this technique has several advantages. The factors that cause the abrasive index to vary from one abrasive to another are not known; it appears, however, that the degree of abrasiveness is not a determining factor. The two methods of calculating abrasion loss—as cc. per hr. and cc. per H.P.-hr.,—usually do not give the same abrasive index; in any standard test method it is therefore essential to state which is to be used. The variation of the abrasive index from one abrasive to another is the same whichever method of calculation is used.

scholarly journals Development of a Test Method to Evaluate Durability of Pavement Joints under Winter Conditions

2021 ◽  
Author(s):  
Conrad Babicz
Keyword(s):  
Visual Inspection ◽  
Strength Loss ◽  
Standard Test ◽  
Test Method ◽  
Concrete Slabs ◽  
Freezing And Thawing ◽  
Premature Failure ◽  
Different Types ◽  
Evaluation Techniques ◽  
Different Levels

In areas with cold winters, premature failure in concrete pavement joints is a frequent phenomenon, yet there is no standard test method for evaluating their durability. In this study, the effectiveness of several evaluation techniques for concrete joint durability were evaluated. Concrete slabs with saw cuts representing joints were made, and exposed to different freezing and thawing/ wetting cycles, and different salt solutions (NaCl, CaCl2, and MgCl2). The durability of the joints was evaluated using measures of strength loss, mass loss, and a visual inspection. It was found that under these exposure conditions, the strength loss and visual inspection modes of evaluation could discern different levels of damage between different types of exposures, and also different concrete mixes (e.g. Different cement contents, strength and the presence or absence of SCM). Further research is required to evaluate the effects of sealants, saturated bases, and higher salt concentrations.

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