Lifetime estimation of vegetable and mineral oil impregnated paper for power transformers

2016 ◽  
Author(s):  
Alexandra Ciuriuc ◽  
Laurentiu Marius Dumitran ◽  
Petru V. Notingher ◽  
Laurentiu Viorel Badicu ◽  
Radu Setnescu ◽  
...  
Keyword(s):  
Mineral Oil ◽  
Power Transformers ◽  
Lifetime Estimation

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.

scholarly journals Optimizing characteristics in mineral insulating oil used in high power transformers

2019 ◽  
pp. 222-228
Author(s):  
Irina Alina Chera Anghel ◽  
Loredana Popescu
Keyword(s):  
Mineral Oil ◽  
The Other ◽  
Power Transformers ◽  
Anaerobic Conditions ◽  
Mineral Oils ◽  
Insulating Liquid ◽  
Different Characteristics ◽  
Aerobic And Anaerobic ◽  
Good Heat ◽  
Aerobic And Anaerobic Conditions

The most commonly used insulating liquid in transformers is mineral oil. Special synthetic applications such as silicone, ester, perchloroethene, etc. are used today in special applications, with different characteristics, very low or nonexistent toxicity to mineral oils used in transformers. On the other hand, they have a much better biodegradability than mineral oils in both aerobic and anaerobic conditions. But they cannot directly replace the mineral oil in operation or in repaired units. They have dielectric properties and good heat transfer but have limited their use to special transformers due to the relatively high cost and availability.

Effect of Waste Vegetable Oil on Cooling Performance and Lifetime of Power Transformers

2020 ◽  
Author(s):  
Ehsan Ebrahimnia-Bajestan ◽  
Mohammad Arjmand ◽  
Hani Tiznobaik
Keyword(s):  
Magnetic Energy ◽  
Power Transformer ◽  
Mineral Oil ◽  
Power Transformers ◽  
Cooling Performance ◽  
Mineral Oils ◽  
Waste Vegetable Oil ◽  
Lower Viscosity ◽  
Insulating Liquid ◽  
Main Factor

Abstract During the operation of a power transformer, a large amount of heat is generated due to the electrical and magnetic energy losses in its core and windings, causing a temperature rise in transformers. This generated heat is known as the main factor for aging the electrical insulating system of a transformer. In this research, we numerically studied the ability of a vegetable-based oil — as an alternative coolant for the petroleum-based oils — on the cooling performance of a power transformer. The studied oil was a biodiesel produced from waste cooking vegetable oils, having lower viscosity compared to traditional mineral oils. We also calculated the aging rate of the transformer in the presence of the biodiesel. The results indicated that compared to the mineral oil, the average hotspot temperature of the transformer is 3 degrees lower when the biodiesel was used. The life expectancy of the transformer with the vegetable-based oil was also significantly longer than the case with mineral oil. In conclusion, this study provided a sustainable way to use an eco-friendly material produced from a waste resource as an alternative insulating liquid for the cooling of power transformers.

Mineral oil lifetime estimation using activation energy

2011 ◽  
Author(s):  
L. V. Badicu ◽  
L. M. Dumitran ◽  
P. V. Notingher ◽  
R. Setnescu ◽  
T. Setnescu
Keyword(s):  
Activation Energy ◽  
Mineral Oil ◽  
Lifetime Estimation

Fillers in Electrical Papers for Power Transformers

2014 ◽  
Vol 875-877 ◽  
pp. 335-340 ◽  
Author(s):  
Primo Alberto Calva ◽  
Aarón Israel Díaz ◽  
Hugo Martínez Gutierrez
Keyword(s):  
Electrical Properties ◽  
Theoretical Analysis ◽  
Structural Parameters ◽  
Dielectric Strength ◽  
Mineral Oil ◽  
Dielectric Behavior ◽  
Power Transformers ◽  
Mechanical Resistance ◽  
Kraft Paper ◽  
Natural Ester

The electric papers have a wide variety of uses like in transformers, cables and power capacitors. Each application involves different requirements related to its mechanical and electric properties. The kraft is the dielectric paper most used due its high mechanical resistance and a dielectric strength of around 5 kV/mm that is increased up to 30 kV/mm when is impregnated with mineral oil and typically has a density of 0.7, nevertheless continuous improvements in the design, for example, of power transformers raise the need to improve its electrical properties particularly those related to its relative permittivity. In this article, structural parameters such as distribution and pore size of kraft paper and theoretical analysis for possible addition of nanofillers to improve their dielectric behavior are reported. A possible and better criterion for designing transformers can be the employment of kraft paper nano-inserted with 5 % of TiO2 or BaTiO3 stew in mineral oil and immersed in natural ester liquid.

Influence of electrical and thermal ageing on the mineral insulating oil performance for power transformer applications

2020 ◽  
Vol 62 (4) ◽  
pp. 222-231
Author(s):  
C Ranga ◽  
A Kumar ◽  
R Chandel
Keyword(s):  
Power Transformer ◽  
Stress Test ◽  
Oxidation Stability ◽  
Chemical Properties ◽  
Mineral Oil ◽  
Thermal Ageing ◽  
Test Cell ◽  
Transformer Oil ◽  
Power Transformers ◽  
Solid Dielectrics

In the present work, a new electrothermal combined stress test cell has been designed and fabricated to conduct accelerated electrothermal ageing. The fabricated test cell includes all possible real working conditions of the transformers. The effects of accelerated electrothermal ageing on the performance of power transformers with thermally upgraded Kraft (TUK), Nomex-910 and Nomex-410 solid dielectrics in conjunction with mineral oil have been investigated. The accelerated electrothermal ageing has been performed for a temperature range of 100°C to 220°C, along with 10 kV electrical stress. Subsequently, several electrical, thermal, mechanical and chemical properties of transformer oil and different paper dielectrics have been determined. It has been observed from the diagnostic test results that Nomex impregnated mineral oil samples have better electrothermal performance as well as oxidation stability when compared to the thermally upgraded Kraft oil samples. Therefore, Nomex insulating materials in conjunction with mineral oil are suggested as alternative solid dielectrics for power transformers in order to achieve better oxidation stability, improved thermal performance for long service runs and reduced operating and maintenance costs. It is envisioned that the present experimental study will be very beneficial to utility managers and end-users of power transformers.

scholarly journals Studies of different types of insulating oils and their mixtures as an alternative to mineral oil for cooling power transformers

Heliyon ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. e01159 ◽  
Author(s):  
Jilani Rouabeh ◽  
Lotfi M'barki ◽  
Amor Hammami ◽  
Ibrahim Jallouli ◽  
Ameni Driss
Keyword(s):  
Mineral Oil ◽  
Power Transformers ◽  
Cooling Power ◽  
Different Types
Sign in / Sign up

Export Citation Format

Share Document