scholarly journals Effect Of Phenol Addition To Transformer Oil Breakdown Voltage

2020 ◽  
Vol 8 (2) ◽  
pp. 77-81
Author(s):  
Amelya Indah Pratiwi
Keyword(s):  
Breakdown Voltage ◽  
Breakdown Strength ◽  
Transformer Oil ◽  
Insulating Oil ◽  
Transformer Insulation ◽  
Is Failure ◽  
Insulation Oil

The failure of transformer insulation often occurs due to various kinds of things, one of which is failure in the oil isolation caused by the condition of oil that has been dirty or has been contaminated with other particles in the transformer. Phenol is a chemical that can purify or cleanse particles or impurities that are in used transformer oil, so that it can increase the breakdown stress on used insulation oil. Phenol contains acid which can attract particles and impurities in the transformer oil which results in a decrease in the breakdown strength of the insulating oil. The results of testing of used isolation oil by adding phenol as much as 10, 15 and 20 ml showed an increase in the value of breakdown voltage with a distance of 2.5 mm ball inlet electrode. Translucent stresses that meet the SPLN standard 49-1: 1982, that is ≥ 30 kV at intervals of 2.5 mm were obtained by adding 20 ml of phenol to the volume of used 400 ml transformer oil

scholarly journals Study of the effect of cellulose fibers on the electrical strength of transformer oil

Vestnik IGEU ◽  
2020 ◽  
pp. 23-33
Author(s):  
O.S. Melnikova ◽  
M.V. Prusakov ◽  
A.A. Zholobov
Keyword(s):  
Electric Field ◽  
Breakdown Voltage ◽  
Breakdown Strength ◽  
Dielectric Strength ◽  
Cellulose Fibers ◽  
Electrode System ◽  
Transformer Oil ◽  
Electrical Strength ◽  
Abrupt Decrease ◽  
Transformer Insulation

The electrical strength of transformer oil is the first parameter in transformer insulation tests. Such tests are carried out in a standard discharger according to the values of breakdown voltage. An abrupt decrease in electrical strength occurs when oil is contaminated with mechanical impurities. The greatest influence on the electric field is exerted by highly conductive cellulose fibers. The field between the electrodes may be severely distorted bya «bridge» of such fibers. At the same time, the influence of such particles is not taken into account in the tests. The problem is to experimentally determine the effect of such impurities on the breakdown strength. Thereby, this research poses and solves the problem of determining the dielectric strength of transformer oil in a standard discharger in the presence of cellulose fibers.To simulate electric field strengths, the ANSYS software package has been used. The basis of the 3D model was a standard measuring cell for determining breakdown voltage, which takes into account the boundary conditions in the form of a cube in which the electrode system is located, and the values of the electric field strength in the center of the electrode system.The electric field tension between the electrodes has been calculated, taking into account the influence of increased conductivity of cellulose fibers. It has been found that the electrical strength of oil gaps of moistened fibers with a length of more than 200 μm is significantly reduced, which is not taken into account when testing transformer oil for breakdown in a standard cell. This leads to inaccuracy in determining the electric strength of transformer oil in existing equipment.The results of the study can be used by operational services to improve the assessment of the quality of transformer oil used in power transformers as insulation. The results also can be used to study the mechanisms of electrophysical processes occurring in liquid dielectrics in the presence of fibers.

scholarly journals A Promising Nano-Insulating-Oil for Industrial Application: Electrical Properties and Modification Mechanism

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 788 ◽  
Author(s):  
Jiaqi Chen ◽  
Potao Sun ◽  
Wenxia Sima ◽  
Qianqiu Shao ◽  
Lian Ye ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Industrial Application ◽  
Breakdown Strength ◽  
Absorption Capacity ◽  
Photon Absorption ◽  
Electrical Performance ◽  
Test Results ◽  
Strong Electron ◽  
Insulating Oil ◽  
Lightning Impulse

Despite being discovered more than 20 years ago, nanofluids still cannot be used in the power industry. The fundamental reason is that nano-insulating oil has poor stability, and its electrical performance decreases under negative impulse voltage. We found that C60 nanoparticles can maintain long-term stability in insulating oil without surface modification. C60 has strong electronegativity and photon absorption ability, which can comprehensively improve the electrical performance of insulating oil. This finding has great significance for the industrial application of nano-insulating oil. In this study, six concentrations of nano-C60 modified insulating oil (CMIO) were prepared, and their breakdown strength and dielectric properties were tested. The thermally stimulated current (TSC) curves of fresh oil (FO) and CMIO were experimentally determined. The test results indicate that C60 nanoparticles can simultaneously improve the positive and negative lightning impulse and power frequency breakdown voltage of insulating oil, while hardly increasing dielectric loss. At 150 mg/L, the positive and negative lightning impulse breakdown voltages of CMIO increased by 7.51% and 8.33%, respectively, compared with those of FO. The AC average breakdown voltage reached its peak (18.0% higher compared with FO) at a CMIO concentration of 200 mg/L. Based on the test results and the special properties of C60, we believe that changes in the trap parameters, the strong electron capture ability of C60, and the absorption capacity of C60 for photons enhanced the breakdown performance of insulating oil by C60 nanoparticles.

Dielectric Strength, Breakdown Voltage and Acidity Test with Respect to Transformer Insulating Oil

2009 ◽  
Vol 62-64 ◽  
pp. 120-125 ◽  
Author(s):  
I.A. Adejumobi
Keyword(s):  
Breakdown Voltage ◽  
Economic Impacts ◽  
Dielectric Strength ◽  
Qualitative Assessment ◽  
Oil Degradation ◽  
British Standard ◽  
Insulating Oil ◽  
Distribution Transformers ◽  
Experimental Values ◽  
Insulation Oil

This paper presented the qualitative assessment of transformer insulating oil. The breakdown voltage, dielectric and acidity tests were electrically and chemically carried out on sixteen samples of transformer insulating oil collected from various serving distribution transformers in Ilorin Metropolis in Nigeria, through the supply authority. The adequacy of the obtained results was determined by comparing experimental values with America Society for Testing and British Standard (BTA4705) pre-requisites. About seventy five percent (75%) of the tested samples failed at least one of the tests, indicating inadequacy in the routine checks. Economic impacts of the obtained results and major causes and prevention of insulation oil degradation were also presented.

Breakdown Strength Characteristic of RBDPO and Mineral Oil Mixture as an Alternative Insulating Liquid for Transformer

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Yusnida M. ◽  
Kiasatina Azmi ◽  
Mohd Azmier Ahmad ◽  
Zulkifli Ahmad ◽  
Mohamad Kamarol
Keyword(s):  
Breakdown Voltage ◽  
Strength Characteristic ◽  
Palm Oil ◽  
Kinematic Viscosity ◽  
Breakdown Strength ◽  
Environmental Concern ◽  
Mineral Oil ◽  
Electrical Insulation ◽  
Insulating Oil ◽  
Insulating Liquid

Mineral oil (MO) works as an important electrical insulation and coolant in transformer which is non-biodegradable and nearly running out. Therefore, for sustainable and environmental concern, an alternative biodegradable insulating oil that potential to replace the mineral oil is introduced. In view of that, the breakdown strength characteristic of Refined Bleached Deodorized Palm Oil (RBDPO) and MO mixtures were investigated by varying the mixing percentage of RBDPO from 0% to 100% at 40oC. The results showed that the breakdown strength of the oil mixture abruptly decline to the minimum breakdown voltage of 50 kV at  20% of  RBDPO mixture and gradually increased when  the ratio of the RBDPO is added. The highest breakdown strength is achieved 87kv at 80% of RBDPO content. The result of kinematic viscosity is also presented.

scholarly journals Preparation of Three Types of Transformer Oil-Based Nanofluids and Comparative Study on the Effect of Nanoparticle Concentrations on Insulating Property of Transformer Oil

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Qi Wang ◽  
Muhammad Rafiq ◽  
Yuzhen Lv ◽  
Chengrong Li ◽  
Kai Yi
Keyword(s):  
Thermal Properties ◽  
Comparative Study ◽  
Breakdown Voltage ◽  
Breakdown Strength ◽  
Transformer Oil ◽  
Standard Methods ◽  
Maximum Value ◽  
Negative Impulse ◽  
The Difference

Nanofluids have the potential to become the alternatives of conventional transformer oil for their exquisite electrical and thermal properties. Three kinds of nanoparticles with distinct conductivities, namely, nonconductive nanoparticle Al2O3, conductive nanoparticle Fe3O4, and semiconductive nanoparticle TiO2, with different concentrations from 5% to 40% w/v were selected and suspended into transformer oil to develop nanofluids. The lightening impulse breakdown strengths of the oil samples with and without nanoparticles were measured according to IEC standard methods. The positive impulse breakdown strength indicated that breakdown strength is first increased up to the maximum value at certain concentration and then starts decreasing. The results of negative impulse breakdown manifested that the breakdown voltages of nanofluids with different concentrations were less than the breakdown voltage of pure transformer oil. Different effect mechanisms of dielectric and conductive nanoparticles were also used to describe the difference among three prepared nanofluids.

Investigation on Voltage Breakdown of Natural Ester Oils Based-On Zno Nanofluids

2015 ◽  
Vol 1119 ◽  
pp. 175-178 ◽  
Author(s):  
Wittawat Saenkhumwong ◽  
Amnart Suksri
Keyword(s):  
Power System ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Breakdown Strength ◽  
Mineral Oil ◽  
Transformer Oil ◽  
Slow Process ◽  
Zno Nanofluids ◽  
Voltage Breakdown ◽  
Natural Ester

Transformer is one of the major component, which is the most important device in power system. Their lifetime depends upon liquid insulation that help transfer the heat out of its winding inside of transformer. Transformer oil uses mineral oil that is the most commonly used has very slow process on decomposition and non-biodegrade. This paper presents the investigation on breakdown voltage of two types of natural ester oils, including palm oil and soy bean based-on ZnO nanofluids. Nanofluids that use nanoparticles modified by use of surfactant that are suspended by process of sonication. Different fraction of nanoparticles were investigated from 0.1% - 0.5% by weight. The breakdown voltage were measured according to ASTM D877. The voltage breakdown strength increased significantly when nanoparticles were added in oils. The obtained results will enable transformer industry to develop liquid insulation dielectric for use in transformer in the future.

scholarly journals Method of calculating the electric strength of oil channels of the main insulation of power transformers

Vestnik IGEU ◽  
2020 ◽  
pp. 48-55
Author(s):  
O.S. Melnikova ◽  
V.S. Kuznetsov
Keyword(s):  
Breakdown Voltage ◽  
High Voltage ◽  
Breakdown Strength ◽  
Dielectric Strength ◽  
Transformer Oil ◽  
Electric Strength ◽  
Power Transformers ◽  
Statistical Characteristics ◽  
Voltage Distribution ◽  
Design Features

The most damage-sensitive unit of power transformers is the main insulation of the oil barrier type. The breakdown of such insulation occurs as a result of the breakdown of the oil channel near the high voltage winding. In accordance with traditional methods of calculating the dielectric strength of insulation, the value of the breakdown strength is determined by empirical formulas depending on the selected width of the oil channel. The existing methods do not consider the influence of the oil channel volume, of the electric strength the statistical characteristics of the oil, the design features of the insulation of power transformers, and do not contain recommendations for creating design models. Thus, to improve the calculation accuracy, it is relevant to develop the evaluation method of dielectric strength of the main insulation of power transformers taking into account the volume and parameters of the breakdown voltage distribution of transformer oil, design features. The research results of the breakdown tension in oil channels with different volumes of transformer oil were used. To improve the accuracy of the calculation and taking into account the design features, the model of the main insulation of power transformers was made in the ANSYS program. Boundary data and assumption of linear stress distribution of transformer coils were considered. A method for calculating the dielectric strength of oil channels of the main insulation of power transformers, considering the volume and parameters of the breakdown voltage distribution of transformer oil was proposed. Unlike the existing methods, when calculating the minimum breakdown strength in the model of the main insulation, the design features of power transformers are taken into account and assumptions are justified to improve the accuracy of the calculation. In accordance with the methodology, the parameters of the dielectric strength of the transformer oil in the oil channel of the high voltage winding of the transformer were calculated. It was concluded that with increase of relative value of breakdown tension, dielectric strength of oil channel is decreasing, and it corresponds to physical sense of breakdown. The method for calculating the dielectric strength of transformer oil can be used when choosing the main insulation of power transformers in design.

Study on Palm Oil and Treated Waste Vegetable Oil Impregnated Paper

2017 ◽  
Vol 744 ◽  
pp. 511-515 ◽  
Author(s):  
Siti Mariam Yusof ◽  
Nuriziani Hussin ◽  
Muzamir Isa ◽  
Mohamad Kamarol Mohd Jamil ◽  
Kiasatina Azmi
Keyword(s):  
Dielectric Loss ◽  
Vegetable Oil ◽  
Palm Oil ◽  
Relative Permittivity ◽  
Breakdown Strength ◽  
Transformer Oil ◽  
Oil Viscosity ◽  
Waste Vegetable Oil ◽  
Natural Oils ◽  
Insulation Oil

Oil impregnated insulation paper plays an important role in a transformer as it insulates the windings from high voltage and current. Other than the type of paper used, the properties of oil such as viscosity, relative permittivity and dielectric loss play a major factor that contributes to the quality of the insulation paper. This paper discussed the sonication and esterification process on palm oil and treated waste vegetable oil and its’ effects on the performance of oil impregnated paper. Basically through these processes, viscosity of oils will reduce. However, the resultant permittivity and dielectric loss as well as its’ breakdown strength are rarely reported. Experiments were set to process (sonicates and esterify) the natural oils prior to the paper impregnation process. Results show that esterification is more effective than sonication process in reducing insulation oil viscosity, relative permittivity and dissipation factors as well as increasing the breakdown voltage of the oil impregnated paper. Palm oil methyl ester (POME) could serve as an excellent insulation oil which is very suitable as transformer oil as well as the impregnation medium for paper insulation.

scholarly journals The Modification Mechanism of Nano-Liquids on Streamer Morphology and Breakdown Strength under Microsecond Pulse

2020 ◽  
Vol 10 (20) ◽  
pp. 7376
Author(s):  
Diangeng Li ◽  
Zicheng Zhang ◽  
Shifei Liu ◽  
Song Li
Keyword(s):  
Breakdown Voltage ◽  
Volume Fraction ◽  
Breakdown Strength ◽  
Transformer Oil ◽  
Nano Particles ◽  
Trapped Electrons ◽  
Scientific Consensus ◽  
Breakdown Process ◽  
Microsecond Pulse

In liquid mediums, whether the breakdown strength can be greatly improved after introducing the nano-particles has been widely investigated, however, there has been no scientific consensus on the modification mechanism of this anomalous phenomenon. In this paper, we first experimentally measured the streamer morphology and breakdown strength in pure transformer oil, TiO2 nano-liquids and Al2O3 nano-liquids under microsecond pulse. The results demonstrated that there are significant differences in streamer morphology between pure transformer oil and nano-liquids, as the streamers in pure transformer oil exhibit thick bush-like qualities, while in nano-liquids they exhibit tree-like qualities. Moreover, the breakdown voltage results show that the breakdown strength of transformer oil is improved after nano-modification, and the TiO2 nano-liquids and Al2O3 nano-liquids have nearly the same optimal volume fraction. The results of the analysis indicate that the modification mechanism of nano-particles is significantly linked to the trapped electrons process. Specifically, the addition of nano-particles can affect the electrons’ density and thus affect the breakdown process and streamer morphology.

scholarly journals Experimental Investigation of Insulating Properties of Vegetable Oil under High Voltage

2019 ◽  
Vol 4 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Sanjida Islam ◽  
Md. Selim Hossain ◽  
Md. Farhamdur Reza ◽  
Md. Mamunur Rashid
Keyword(s):  
Experimental Investigation ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
High Voltage ◽  
Coconut Oil ◽  
Cost Effective ◽  
Transformer Oil ◽  
Insulating Oil ◽  
High Breakdown Voltage ◽  
Mixed Oil

Due to concerns over the world’s energy necessity and environmental impact of mineral oil, these conditions induce many researchers to search for substitute sources for insulating oil. Alternatives insulating oil with biodegradable characteristics, environment friendly and presented in different countries including Bangladesh such as vegetable oils have been proposed for high voltage applications. In this paper, a relative measurement of breakdown voltage through experimental investigation of coconut, mustard, soybean, and palm oil and their blend (which is available in Bangladesh and cost effective) is presented. Break down voltage was measure with different electrode configuration by changing gap distance. The results show that the blend of (50% coconut oil + 50% palm oil) got high breakdown voltage in mushroom-mushroom electrode, and other side in plane-plane type pure soybean oil got high breakdown voltage, compared with transformer oil. The presented result illustrate that the proposed mixed oil provides better performance than the rise husk oil.

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