Transformer Mineral Oil Mixtures Characterization by Isothermal Charging Currents

2013 ◽  
Vol 664 ◽  
pp. 632-637
Author(s):  
Tahar Toudja ◽  
Hocine Moulai ◽  
Azzeddine Nacer ◽  
Abdeslem Beldjillali ◽  
Nadia Saidi ◽  
...  
Keyword(s):  
Power Transformer ◽  
Physicochemical Characteristics ◽  
Field Application ◽  
Transformer Oil ◽  
Oil Mixtures ◽  
Physicochemical Methods ◽  
High Voltage Insulation ◽  
Solid Dielectrics ◽  
Good Agreement

This work aims at the characterization of power transformer oil mixtures by using dc charging currents measurements for long field application times. The principle of this approach is inspired from the technique of measurements carried out on solid dielectrics used in high voltage insulation. It will be applied to characterize mixtures between two compatible oils of different provenances and ages. The obtained results are conclusive and reinforce those obtained by classical physicochemical methods of characterization. For the purpose, we intent to link between the space charge behavior in the insulation and its several characteristics. Moreover, in addition to the fact that the obtained results are in good agreement with the physicochemical characteristics, the charging currents reported at room temperature enabled us to determine the mixture resistivity and charge carriers' mobility.

TDLAS-Based Detection of Dissolved Methane in Power Transformer Oil and Field Application

2018 ◽  
Vol 18 (6) ◽  
pp. 2318-2325 ◽  
Author(s):  
Jun Jiang ◽  
Mingxin Zhao ◽  
Guo-Ming Ma ◽  
Hong-Tu Song ◽  
Cheng-Rong Li ◽  
...  
Keyword(s):  
Power Transformer ◽  
Field Application ◽  
Transformer Oil ◽  
Dissolved Methane

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 Research on Acetylene Sensing Properties and Mechanism of SnO2Based Chemical Gas Sensor Decorated with Sm2O3

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Qu Zhou ◽  
Meiqing Cao ◽  
Wude Li ◽  
Chao Tang ◽  
Shiping Zhu
Keyword(s):  
Gas Sensing ◽  
Power Transformer ◽  
Transformer Oil ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Hydrocarbon Gases ◽  
Promising Candidate ◽  
Analysis System ◽  
Fault Characteristic

Acetylene C2H2gas is one of the most important fault characteristic hydrocarbon gases dissolved in oil immersed power transformer oil. This paper reports the successful preparation and characterization of samarium oxide Sm2O3decorated tin oxide SnO2based sensors with hierarchical rod structure for C2H2gas detection. Pure and Sm2O3decorated SnO2sensing structures were synthesized by a facile hydrothermal method and characterized by XRD, FESEM, TEM, EDS, and XPS measurements, respectively. Planar chemical gas sensors with the synthesis samples were fabricated, and their sensing performances to C2H2gas were systematically performed and automatically recorded by a CGS-1 TP intelligent gas sensing analysis system. The optimum operating temperature of the Sm2O3decorated SnO2based sensor towards 50 μL/L of C2H2is 260°C, and its corresponding response value is 38.12, which is 6 times larger than the pure one. Its response time is about 8–10 s and 10–13 s for recovery time. Meanwhile good stability and reproducibility of the decorated sensor to C2H2gas are also obtained. Furthermore, the proposed sensor exhibits excellent C2H2selectivity among some potential interface gases, like H2and CO gas. All sensing results indicate the sensor fabricated with oxide Sm2O3decorated SnO2nanorods might be a promising candidate for C2H2detection in practice.

FURTHER CONTRIBUTION FOR EVALUATING THE AGING OF TRANSFORMER OIL OF POWER TRANSFORMER

2015 ◽  
Vol 43 (2) ◽  
pp. 211-226
Author(s):  
Sobhy S. Dessouky ◽  
Adel El Faraskoury ◽  
Sherif Ghoneim ◽  
Ahmed Haassan
Keyword(s):  
Power Transformer ◽  
Transformer Oil

scholarly journals Characterization of Tiled Architecture for C-Band 1-Bit Beam-Steering Transmitarray

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1259
Author(s):  
Dmitry Kozlov ◽  
Irina Munina ◽  
Pavel Turalchuk ◽  
Vitalii Kirillov ◽  
Alexey Shitvov ◽  
...  
Keyword(s):  
Communication Systems ◽  
Beam Steering ◽  
Unit Cell ◽  
Electromagnetic Simulations ◽  
Fifth Generation ◽  
Full Wave ◽  
Array Architecture ◽  
Modulation Pattern ◽  
Good Agreement

A new implementation of a beam-steering transmitarray is proposed based on the tiled array architecture. Each pixel of the transmitarray is manufactured as a standalone unit which can be hard-wired for specific transmission characteristics. A set of complementary units, providing reciprocal phase-shifts, can be assembled in a prescribed spatial phase-modulation pattern to perform beam steering and beam forming in a broad spatial range. A compact circuit model of the tiled unit cell is proposed and characterized with full-wave electromagnetic simulations. Waveguide measurements of a prototype unit cell have been carried out. A design example of a tiled 10 × 10-element 1-bit beam-steering transmitarray is presented and its performance benchmarked against the conventional single-panel, i.e., unibody, counterpart. Prototypes of the tiled and single-panel C-band transmitarrays have been fabricated and tested, demonstrating their close performance, good agreement with simulations and a weak effect of fabrication tolerances. The proposed transmitarray antenna configuration has great potential for fifth-generation (5G) communication systems.

scholarly journals Isolation and Characterization of Phages Active against Paenibacillus larvae Causing American Foulbrood in Honeybees in Poland

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1217
Author(s):  
Ewa Jończyk-Matysiak ◽  
Barbara Owczarek ◽  
Ewa Popiela ◽  
Kinga Świtała-Jeleń ◽  
Paweł Migdał ◽  
...  
Keyword(s):  
Biological Properties ◽  
Field Application ◽  
Paenibacillus Larvae ◽  
American Foulbrood ◽  
Isolation And Characterization ◽  
Safety Studies ◽  
Spreading Disease ◽  
Intended Use ◽  
Antibacterial Potential

The aim of this study was the isolation and characterization, including the phage effect on honeybees in laboratory conditions, of phages active against Paenibacillus larvae, the causative agent of American Foulbrood—a highly infective and easily spreading disease occurring in honeybee larva, and subsequently the development of a preparation to prevent and treat this dangerous disease. From the tested material (over 2500 samples) 35 Paenibacillus spp. strains were obtained and used to search for phages. Five phages specific to Paenibacillus were isolated and characterized (ultrastructure, morphology, biological properties, storage stability, and genome sequence). The characteristics were performed to obtain knowledge of their lytic potential and compose the final phage cocktail with high antibacterial potential and intended use of future field application. Preliminary safety studies have also been carried out on healthy bees, which suggest that the phage preparation administered is harmless.

scholarly journals Visco-Hyperelastic Characterization of the Equine Immature Zona Pellucida

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1223
Author(s):  
Elisa Ficarella ◽  
Mohammad Minooei ◽  
Lorenzo Santoro ◽  
Elisabetta Toma ◽  
Bartolomeo Trentadue ◽  
...  
Keyword(s):  
Zona Pellucida ◽  
Soft Matter ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Nonlinear Material ◽  
Prony Series ◽  
Critical Comparison ◽  
Highly Nonlinear ◽  
Good Agreement

This article presents a very detailed study on the mechanical characterization of a highly nonlinear material, the immature equine zona pellucida (ZP) membrane. The ZP is modeled as a visco-hyperelastic soft matter. The Arruda–Boyce constitutive equation and the two-term Prony series are identified as the most suitable models for describing the hyperelastic and viscous components, respectively, of the ZP’s mechanical response. Material properties are identified via inverse analysis based on nonlinear optimization which fits nanoindentation curves recorded at different rates. The suitability of the proposed approach is fully demonstrated by the very good agreement between AFM data and numerically reconstructed force–indentation curves. A critical comparison of mechanical behavior of two immature ZP membranes (i.e., equine and porcine ZPs) is also carried out considering the information on the structure of these materials available from electron microscopy investigations documented in the literature.

scholarly journals Fuzzy Algorithm for Power Transformer Diagnostics

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nitin K. Dhote ◽  
Jagdish B. Helonde
Keyword(s):  
Gas Chromatography ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Power Transformer ◽  
Gas Analysis ◽  
Transformer Oil ◽  
Dissolved Gas ◽  
Inference System ◽  
Incipient Faults ◽  
The World

Dissolved gas analysis (DGA) of transformer oil has been one of the most reliable techniques to detect the incipient faults. Many conventional DGA methods have been developed to interpret DGA results obtained from gas chromatography. Although these methods are widely used in the world, they sometimes fail to diagnose, especially when DGA results fall outside conventional methods codes or when more than one fault exist in the transformer. To overcome these limitations, the fuzzy inference system (FIS) is proposed. Two hundred different cases are used to test the accuracy of various DGA methods in interpreting the transformer condition.

Estimation of Interlayer Thickness in Inorganic Particulate-Filled Polymer Composites

2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang
Keyword(s):  
Polymer Composites ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Interfacial Structure ◽  
Interlayer Thickness ◽  
Filled Polymer ◽  
Mechanical And Physical Properties ◽  
The Relationship ◽  
Good Agreement

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.

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