scholarly journals A Review on Synthetic Ester Liquids for Transformer Applications

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6429
Author(s):  
Pawel Rozga ◽  
Abderrahmane Beroual ◽  
Piotr Przybylek ◽  
Maciej Jaroszewski ◽  
Konrad Strzelecki
Keyword(s):  
Review Paper ◽  
Research Work ◽  
Gas Analysis ◽  
Point Of View ◽  
Research Progress ◽  
Dissolved Gas ◽  
Synthetic Ester ◽  
Static Electrification ◽  
Fundamental Point ◽  
Lightning Impulse

Synthetic esters have become more and more popular in last few decades, explaining the increasing number of units filled with this liquid year by year. They have been investigated under different aspects, both from the fundamental point of view and breakdown mechanisms, well as from the application point of view. However, their use in high voltage equipment is always a challenge and deeper knowledge of the various aspects that can be encountered in their exploitation is needed. The intent of this review paper is to present the recent research progress on synthetic ester liquid in relation to the selected issues, most important for ester development in the authors’ opinion. The described issues are the breakdown performance of synthetic esters, lightning impulse strength and pre-breakdown phenomena of synthetic esters, synthetic esters-based nanofluids, combined paper-synthetic ester based insulating systems, application of synthetic ester for retro-filling and drying of mineral oil-immersed transformers, DGA(dissolved gas analysis)-based diagnosis of synthetic esters filled transformers as well as static electrification of synthetic esters. The different sections are based both on the data available in the literature, but above all on the authors’ own experience from their research work on synthetic ester liquids for electrical application purposes.

scholarly journals Using the Analysis of the Gases Dissolved in Oil in Diagnosis of Transformer Bushings with Paper-Oil Insulation—A Case Study

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6713
Author(s):  
Tomasz Piotrowski ◽  
Pawel Rozga ◽  
Ryszard Kozak ◽  
Zbigniew Szymanski
Keyword(s):  
Positive Result ◽  
Gas Analysis ◽  
Power Transformers ◽  
Ratio Method ◽  
Dissolved Gas ◽  
Step Process ◽  
Lightning Impulse ◽  
Triangle Method ◽  
Inside Part

The article describes a case study when the voltage collapse during lightning impulse tests of new power transformers was noticed and when the repeated tests finished with a positive result. The step-by-step process of reaching the conclusion on the basis of dissolved gas analysis (DGA) as a key method of the investigations was presented. The considerations on the possible source of the analysis showed that the Duval triangle method, used in the analysis of the concentration of gases dissolved in oil samples taken from bushings, more reliably and unambiguously than the ratio method recommended in the IEC 60599 Standard, indicated a phenomenon which was identified in the insulation structure of bushings analyzed. Additionally, the results from DGA were found to be consistent with an internal inspection of bushings, which showed a visible trace of discharge on the inside part of the epoxy housing, as a result of the lightning induced breakdown.

Fault Prediction Based on Dissolved Gas Concentration from Insulating Oil in Power Transformer Using Neural Network

2013 ◽  
Vol 441 ◽  
pp. 312-317
Author(s):  
Fang Ming Yang ◽  
Chuan Liu ◽  
Yong Sun ◽  
Qi Long ◽  
You Ping Fan
Keyword(s):  
Neural Network ◽  
Power Transformer ◽  
Research Work ◽  
Gas Analysis ◽  
Fault Prediction ◽  
Dissolved Gas ◽  
Large Power ◽  
Electrical Stress ◽  
The Neural Network ◽  
Trained Neural Network

Reliable and continued performance of power transformer is the key to profitable generation and transmission of electric power. Failure of a large power transformer not only results in the loss of expensive equipment, but it can cause significant guarantied damage as well. Replacement of that transformer can take up to a year if the failure is not disastrous and can result in tremendous revenue losses and fines. A power transformer in operation is subjected to various stresses like thermal stress and electrical stress, resulting in liberation of gases from the hydrocarbon mineral oil. Dissolved gas analysis is a technique used to assess incipient faults of the transformer by analyzing specific dissolved gas concentrations arising from the deterioration of the transformer. DGA is used not only as a diagnostic tool but also to track apparatus failure. In this research work the dissolved gas values measured for a 230kV / 110kV power transformer which are obtained from electricity board are used as references to the developed neural network. The neural network is trained and the transformer faults are predicted. The trained neural network shows the good performance for the prediction of fault in a 230kV/110kV power transformer.

Study of Parameters Affecting the Aging of Transformer Oil

2022 ◽  
Vol 1048 ◽  
pp. 89-100
Author(s):  
S. Tamil Selvi ◽  
Madhusudan Saranathan ◽  
Pa Hari Krishna Achuthan ◽  
R. Abhishek ◽  
Adhitya Ravi
Keyword(s):  
Moisture Content ◽  
Breakdown Voltage ◽  
High Performance ◽  
Research Work ◽  
Gas Analysis ◽  
Transformer Oil ◽  
Dissolved Gas ◽  
Safety Hazards ◽  
Long Term Observation

An electricity board acquires several transformers from a manufacturer in a belief that their advertised lifetime of the transformer thus purchased is true. However, they don’t take in the case of negligence in maintenance of transformer, which is a strenuous job. The advertised thirty-year lifetime is reduced to a mere two-year lifetime, mainly because of the degradation of the insulation medium (Transformer oil), thus increasing losses in the transformer and decreasing its efficiency. The degradation of transformer oil leads to safety hazards like transformer bursting, consequently forcing the electricity board to replace the transformer, thus incurring huge amount of costs. This is the most relatable problem faced by the electricity board in every state. This research work aims at listing out various properties of transformer oil and ascertaining major impurities in a transformer oil by testing it using various techniques. The proposed work deals with long term observation and analysis of transformer oil to determine its degradation rate. Breakdown voltage, Moisture content, Resistivity, Acidity, Furan Analysis and Dissolved Gas Analysis were done using Mushroom electrodes, Karl Fischer Titration test, Tan delta test, Potassium Hydroxide Titration, High performance liquid chromatography, and dissolved gas analyzer respectively. The results reveal that, deviation of Breakdown Voltage, Moisture content, and 2-Furaldehyde (1197ppb) from the permissible limits can indicate the aging of the transformer.

Radiation Damage in Ceramics

1982 ◽  
Vol 40 ◽  
pp. 600-603
Author(s):  
T. E. Mitchell ◽  
M. R. Pascucci ◽  
R. A. Youngman
Keyword(s):  
Radiation Damage ◽  
Outer Space ◽  
Point Of View ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Storage Media ◽  
Transmission Electron ◽  
Fundamental Point ◽  
Small Defect ◽  
Present Understanding

1. Introduction. Studies of radiation damage in ceramics are of interest not only from a fundamental point of view but also because it is important to understand the behavior of ceramics in various practical radiation enyironments- fission and fusion reactors, nuclear waste storage media, ion-implantation devices, outer space, etc. A great deal of work has been done on the spectroscopy of point defects and small defect clusters in ceramics, but relatively little has been performed on defect agglomeration using transmission electron microscopy (TEM) in the same kind of detail that has been so successful in metals. This article will assess our present understanding of radiation damage in ceramics with illustrations using results obtained from the authors' work.

scholarly journals Towards Precise Interpretation of Oil Transformers via Novel Combined Techniques Based on DGA and Partial Discharge Sensors

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2223 ◽  
Author(s):  
Sayed A. Ward ◽  
Adel El-Faraskoury ◽  
Mohamed Badawi ◽  
Shimaa A. Ibrahim ◽  
Karar Mahmoud ◽  
...  
Keyword(s):  
Power Transformer ◽  
Partial Discharge ◽  
Electrical Power ◽  
Diagnostic Techniques ◽  
Gas Analysis ◽  
Economic Losses ◽  
Dissolved Gas ◽  
Electricity Transmission ◽  
Dissolved Gas Analysis ◽  
Precise Interpretation

Power transformers are considered important and expensive items in electrical power networks. In this regard, the early discovery of potential faults in transformers considering datasets collected from diverse sensors can guarantee the continuous operation of electrical systems. Indeed, the discontinuity of these transformers is expensive and can lead to excessive economic losses for the power utilities. Dissolved gas analysis (DGA), as well as partial discharge (PD) tests considering different intelligent sensors for the measurement process, are used as diagnostic techniques for detecting the oil insulation level. This paper includes two parts; the first part is about the integration among the diagnosis results of recognized dissolved gas analysis techniques, in this part, the proposed techniques are classified into four techniques. The integration between the different DGA techniques not only improves the oil fault condition monitoring but also overcomes the individual weakness, and this positive feature is proved by using 532 samples from the Egyptian Electricity Transmission Company (EETC). The second part overview the experimental setup for (66/11.86 kV–40 MVA) power transformer which exists in the Egyptian Electricity Transmission Company (EETC), the first section in this part analyzes the dissolved gases concentricity for many samples, and the second section illustrates the measurement of PD particularly in this case study. The results demonstrate that precise interpretation of oil transformers can be provided to system operators, thanks to the combination of the most appropriate techniques.

scholarly journals Removal of Micropollutants by Ozone-Based Processes

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1013
Author(s):  
Ján Derco ◽  
Andreja Žgajnar Gotvajn ◽  
Oľga Čižmárová ◽  
Jozef Dudáš ◽  
Lenka Sumegová ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Review Paper ◽  
Drinking Water Treatment ◽  
Emerging Pollutants ◽  
Research Trends ◽  
Point Of View ◽  
Priority Substances ◽  
Research Projects ◽  
Harmful Substances ◽  
Emerging Substances

Micropollutants and emerging substances pose a serious problem to environmental sustainability and remediation, due to their widespread use and applications in everyday life. This group of chemicals is diverse but with common toxic and harmful properties. Their concentration in the environment is often very low; however, due to their recalcitrant nature, they are persistent in air, water, and soil. From an engineering point of view, the challenge is not straightforward. It is difficult to remove these contaminants from complex mixtures of substances by conventional methods used in wastewater and drinking water treatment. Ozonation and ozone-based AOPs are accepted processes of degradation of resistant substances or at least enhancement of their biodegradability. The aim of this review paper is to present research trends aimed at solving problems in the research and application of ozone-based processes in the removal of micropollutants from wastewater, thus preventing leakage of harmful substances into surface water, soil, and groundwater and facilitating the reuse of wastewater. Priority substances, micropollutants and emerging pollutants, as well as processes and technologies for their transformation and elimination, are briefly specified. Results obtained by the authors in solving research projects that were aimed at eliminating selected micropollutants by ozonation and ozone-based AOPs are also presented. This review focuses on selected alkylphenols, petroleum substances, and organochlorine pesticides.

scholarly journals Curcumin: Modern Applications for a Versatile Additive

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 519
Author(s):  
Florentina Monica Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Violeta Purcar
Keyword(s):  
Bacterial Infections ◽  
Natural Compound ◽  
Review Paper ◽  
Curcuma Longa ◽  
Antibacterial Properties ◽  
Point Of View ◽  
Nano Particles ◽  
Synergistic Activity ◽  
Quality Of Food

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.

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