scholarly journals Electrical insulating liquid: A review

2017 ◽  
Vol 07 (04) ◽  
pp. 1730001 ◽  
Author(s):  
Deba Kumar Mahanta ◽  
Shakuntala Laskar
Keyword(s):  
Coconut Oil ◽  
Mineral Oil ◽  
Insulating Materials ◽  
Insulating Material ◽  
Insulating Liquids ◽  
Materials Used ◽  
Insulating Liquid ◽  
Transformer Insulation ◽  
Oil Sunflower

Insulating liquid plays an important role for the life span of the transformer. Petroleum-based mineral oil has become dominant insulating liquid of transformer for more than a century for its excellent dielectric and cooling properties. However, the usage of petroleum-based mineral oil, derived from a nonrenewable energy source, has affected the environment for its nonbiodegradability property. Therefore, researchers direct their attention to renewable and biodegradable alternatives. Palm fatty acid ester, coconut oil, sunflower oil, etc. are considered as alternatives to replace mineral oil as transformer insulation liquid. This paper gives an extensive review of different liquid insulating materials used in a transformer. Characterization of different liquids as an insulating material has been discussed. An attempt has been made to classify different insulating liquids-based on different properties.

Efficiency Improvement of Single Phase Transformer Using Virgin Coconut Oil

2015 ◽  
Vol 793 ◽  
pp. 187-191
Author(s):  
A.A.H. Zaidi ◽  
Nuriziani Hussin ◽  
Dina Maizana
Keyword(s):  
Single Phase ◽  
Renewable Energy Sources ◽  
Coconut Oil ◽  
Mineral Oil ◽  
Virgin Coconut Oil ◽  
Phase Step ◽  
Before And After ◽  
Good Improvement ◽  
Insulating Liquid ◽  
Transformer Insulation

The application of mineral oil in transformer is prominently act as and insulator and a coolant liquid. More often, petroleum based oil is used because most its elements are good to act as insulator such as excellent heat transfer and low in viscosity. Anyhow, the usage of mineral oil in transformer is possibly hazardous to the environment considering that it is poor biodegradable liquid where when a spill or leakage happens, it could pollute the environment surroundings. Moreover, it is known as a non-renewable energy sources, the world will be out of it someday near future. For this reason, a new option of transformer insulation liquid is studied. Vegetable oil is a fully biodegradable insulating liquid and for this paper, coconut oil is used as the insulator. In this paper, it concentrates on the performance of the transformer before and after virgin coconut oil is applied in a single-phase step down transformer that use the 220 V supply and 50 Hz frequency. Transformer is connected to 110V induction motor as load and has been test in two conditions, dry and after virgin coconut oil is applied. Comparison is made from both results and clearly shown a good improvement when virgin coconut oil is used as insulation oil.

scholarly journals Study of Breakdown Voltage of Vegetables oil with SiO2 Nanoparticle Additive

2018 ◽  
Vol 12 (1) ◽  
pp. 296
Author(s):  
Muhammad Bin Yahya ◽  
Fatin Amirah Binti Amirrazli
Keyword(s):  
Breakdown Voltage ◽  
Palm Oil ◽  
Coconut Oil ◽  
Mineral Oil ◽  
Partial Discharges ◽  
Transformer Oil ◽  
Different Temperatures ◽  
The Mean ◽  
Insulating Liquid ◽  
Positive Results

<p>This paper investigates the suitability of vegetable oils to replace mineral oil based on its AC breakdown voltage, partial discharge and viscosity. The purpose of the study is to analyze the effect of the nanofluids containing SiO<sub>2</sub> nanoparticle in vegetables oils; namely, Coconut oil and Palm oil. A nanofluid is a fluid containing nanoparticles. However, the precise effects on the electrical properties is still uncertain. For decades, transformers use petroleum-based mineral oil because of its good dielectric properties and cooling capability. Coconut oil (CO) and Palm oil (PO) are thought to be   suitable alternatives to replace mineral oil as transformer oil as they are sustainable and available in plenty as natural resources.  It was obtained in this study that the breakdown voltages of these raw oils have fulfilled the standard specifications of good insulating liquid. However, the addition of SiO<sub>2</sub> did not improve the AC breakdown voltage and viscosity of coconut oil and palm oil at different temperatures. However, the addition of SiO<sub>2</sub> gave positive results in the values of partial discharges in which the presence of the nanoparticles has greatly reduced the mean volume of partial discharges for both coconut oil and palm oil.</p>

On Performance & Application Prospect of Inorganic Materials Used for Exterior Walls Insulation in Hot Summer and Cold Winter Zone

2012 ◽  
Vol 535-537 ◽  
pp. 1913-1917
Author(s):  
Lu Jun
Keyword(s):  
Aluminum Sulfate ◽  
Inorganic Materials ◽  
Future Market ◽  
Cold Winter ◽  
Insulating Materials ◽  
Insulating Material ◽  
Thermal Insulating ◽  
First Choice ◽  
The Common ◽  
Materials Used

In response to the requirement of saving 65% energy in hot summer and cold winter zone, a comprehensive comparative analysis has been conducted in various aspects towards the common organic and inorganic thermal insulating materials in the market. And a conclusion has been drawn that, on the basis of reaching the standards, inorganic thermal insulating materials represented by aluminum sulfate boast obvious advantages compared to organic ones in terms of fire proofing, durability, economical efficiency, and environmental protection etc. Thus, the inorganic thermal insulating material will become the first choice in future market.

scholarly journals A novel self-healing power cable insulating material based on host–guest interactions

RSC Advances ◽  
2018 ◽  
Vol 8 (45) ◽  
pp. 25313-25318 ◽  
Author(s):  
Lei Peng ◽  
Manjun Zhang ◽  
Musong Lin ◽  
Qiang Fu
Keyword(s):  
Power Cable ◽  
Self Healing ◽  
Power Cables ◽  
Insulating Materials ◽  
Insulating Material ◽  
Healing Power ◽  
Materials Used

The insulating materials used in power cables are susceptible to damage and cracks during installation and operation.

scholarly journals Electrostatic Charging Tendency Analysis Concerning Retrofilling Power Transformers with Envirotemp FR3 Natural Ester

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4420 ◽  
Author(s):  
Maciej Zdanowski
Keyword(s):  
Mineral Oil ◽  
Volume Density ◽  
Point Of View ◽  
Pipe Material ◽  
Mineral Oils ◽  
Insulating Liquids ◽  
Electrostatic Charging ◽  
Tendency Analysis ◽  
Insulating Liquid ◽  
Natural Ester

Natural and synthetic esters are liquids characterized by insulating properties, high flash point, and biodegradability. For this reason, they are more and more often used as an alternative to conventional mineral oils. Esters are used to fill new or operating transformers previously filled with mineral oil (retrofilling). It is technically unfeasible to completely remove mineral oil from a transformer. Its small residues create with esters a mixture with features significantly different from those of the base liquids. This article presents electrostatic charging tendency (ECT) tests for mixtures of fresh and aged Trafo EN mineral oil with Envirotemp FR3 natural ester from the retrofilling point of view. Under unfavorable conditions, the flow electrification phenomenon can damage the solid insulation in transformers with forced oil circulation. The ECT of the insulating liquids has been specified using the volume density of the qw charge. This parameter has been determined using the Abedian–Sonin model on the basis of the electrification current measured in the flow system, as well as selected physicochemical properties of the liquids. It was shown that ECT is strongly dependent on the type of insulating liquid and pipe material, as well as the composition of the mixtures. The most important finding from the research is that a small amount (up to 10%) of fresh and aged mineral oil is effective in reducing the ECT of Envirotemp FR3 natural ester.

scholarly journals Oxidation Stability of Natural Ester Modified by Means of Fullerene Nanoparticles

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 490
Author(s):  
Dominika Szcześniak ◽  
Piotr Przybylek
Keyword(s):  
Aging Process ◽  
Power Transformer ◽  
Oxidation Stability ◽  
Acid Number ◽  
Pure Liquid ◽  
Insulating Liquids ◽  
Fullerene Nanoparticles ◽  
Materials Used ◽  
Insulating Liquid ◽  
Natural Ester

Increasing environmental demands influence the requirements for devices and materials used in the power industry. One example is a power transformer and an electro-insulating liquid used in it. In order to meet these requirements, electro-insulating liquids should be characterized by, inter alia, high biodegradability and good fire properties. One of such liquids is natural ester. However, its oxidation stability is low in comparison to mineral oil and demands improvement, which can be achieved by the addition of an antioxidant. The authors of this work used fullerene nanoparticles for that purpose. Pure natural ester samples were prepared, and samples with two concentrations of fullerene, 250 mg/L and 500 mg/L in natural ester. All these samples were aged in a thermal oxidation process. Thereafter, the aging properties of all the samples were compared to assess the oxidation stability of modified liquids. Moreover, the electrical properties of prepared insulating liquids were investigated to assess if fullerene deteriorates these properties after aging process. Based on the obtained results, it was proved that the aging process slowed down in the case of both fullerene concentrations in ester. The acid number of natural ester modified using fullerene was lower than in the case of pure liquid.

scholarly journals Conductivity Characterization of Insulation and Its Effects on the Calculation of the Electric Field Distribution in HVDC Cables

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shili Liu ◽  
Wei Wei ◽  
Tao Liu ◽  
Zhaoyu Hui ◽  
Yuhua Hang ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Fields ◽  
Electric Field Distribution ◽  
Coincidence Degree ◽  
Insulating Materials ◽  
High Voltage Direct Current ◽  
Different Temperatures ◽  
Materials Used

The calculation of an electric field distribution provides the basis for the structural design of the insulation, and an accurate characterization of conductivity as a function of temperature and electric field forms an important basis for the simulation of the electric field distribution in HVDC (high-voltage direct current) cables. However, the conductivity functions that describe the insulating materials used for HVDC cables in different studies are different, and very little has been reported regarding how to choose the most accurate function. In this work, the conductivity of insulating materials used for HVDC cables is characterized, and the effects of the conductivity characterization on the simulation of the electric field in HVDC cables are studied. First, eight common conductivity functions are compared qualitatively. Then, the conductivities of XLPE for different temperatures and electric fields are measured, and a data fitting technique is used to analyze the coincidence degree between different functions and the test results. Finally, the steady-state electric field distributions of HVDC cables for different temperature gradients are simulated in COMSOL Multiphysics. The results show that the sum of the square of the relative errors of the fitting when using the original functions is larger than that achieved when using the logarithmic form of the functions. The deviations in the electric field caused by taking the logarithm of different functions are smaller.

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.

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