scholarly journals Investigation of Distribution Transformers Vibrations in Terms of Core and Winding Condition Assessment

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Jaroslaw Gielniak ◽  
Magdalena Czerniak
Keyword(s):  
Trend Analysis ◽  
Frequency Spectrum ◽  
Condition Assessment ◽  
The State ◽  
Active Part ◽  
Power Transformers ◽  
Vibration Acceleration ◽  
Large Share ◽  
Distribution Transformers ◽  
Different Types

This work refers to the criterion values used to assess the state of the active part of the transformer based on the analysis of the effective value of the total vibration acceleration and the frequency spectrum. It was proved in the work that the criteria values should be differentiated for transformers of different rated power. Transformers with lower rated power are characterized by lower RMS values of vibration acceleration than units with higher rated power, which cannot remain without impact on the criteria values. Trend analysis of the total aRMS values may reveal increasing defects before the currently applicable criteria values are exceeded. In addition, the influence of the position of the sensor on the frequency spectrum of the obtained signals was analyzed. It was proved that the sensors should be mounted in the middle of the transformer tank, between its lower part and the cover. The dependence of RMS value of vibration acceleration on no-load losses was also determined for transformers of different types but the same rated power. This relationship will not have a large share in the total vibrations of the transformer, due to slight changes in the value of aRMS occurring for all analyzed units.

scholarly journals Condition assessment of power transformers status based on moisture level using fuzzy logic techniques

2018 ◽  
Vol 9 (1) ◽  
pp. 17 ◽  
Author(s):  
Vezir Rexhepi ◽  
Petar Nakov
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Electrical Breakdown ◽  
Power Transformer ◽  
Condition Assessment ◽  
The State ◽  
Moisture Level ◽  
Power Transformers ◽  
Safe Operation ◽  
Fuzzy Logic Technique

Power transformers are one of the most expensive components; therefore the focus on their status and its continuous operation is the primary task. In the power systems, condition assessment of performance and reliability is based on the state of components, measurements, testing and maintenance as well as their diagnosis. Hence, condition assessment of power transformer parameters is the most important regarding their status and finding incipient failures. Among many factors, the most factors that affects the safe operation and life expentancy of the transformer is the moisture in oil. It is known that the low moisture oil in power transformers causes many problems including electrical breakdown, increase the amount of partial discharge, decreases the dielectric withstand strength and other phenomena. Thus, knowledge about the moisture concentration in a power transformer is significantly important for safe operation and lifespan. In this study, moisture level in oil is estimated and its status classification is proposed by using fuzzy logic techniques for the power transformer monitoring and condition assessment. Moreover, the goal of the study is to find methods and techniques for the condition assessment of power transformers status based on the state of moisture in oil using the fuzzy logic technique. These applied techniques increase the power system reliability, help to reduce incipient failures, and give the better maintenance plan using an algorithm based on logic rules. Also, by using the fuzzy logic techniques, it is easier to prevent failures which may have consequences not only for transformers but also for the power system as a whole.

Research on transformer vibration monitoring and diagnosis based on Internet of things

2021 ◽  
Vol 30 (1) ◽  
pp. 677-688
Author(s):  
Zhenzhuo Wang ◽  
Amit Sharma
Keyword(s):  
Internet Of Things ◽  
Power Distribution ◽  
Vibration Analysis ◽  
Vibration Monitoring ◽  
Power Transformers ◽  
Normal Operation ◽  
Analysis Method ◽  
Power Distribution Network ◽  
Monitoring And Diagnosis ◽  
Distribution Transformers

Abstract A recent advent has been seen in the usage of Internet of things (IoT) for autonomous devices for exchange of data. A large number of transformers are required to distribute the power over a wide area. To ensure the normal operation of transformer, live detection and fault diagnosis methods of power transformers are studied. This article presents an IoT-based approach for condition monitoring and controlling a large number of distribution transformers utilized in a power distribution network. In this article, the vibration analysis method is used to carry out the research. The results show that the accuracy of the improved diagnosis algorithm is 99.01, 100, and 100% for normal, aging, and fault transformers. The system designed in this article can effectively monitor the healthy operation of power transformers in remote and real-time. The safety, stability, and reliability of transformer operation are improved.

Condition assessment of power transformers based on multi-attributes using fuzzy logic

2017 ◽  
Vol 11 (8) ◽  
pp. 983-990 ◽  
Author(s):  
Chilaka Ranga ◽  
Ashwani Kumar Chandel ◽  
Rajeevan Chandel
Keyword(s):  
Fuzzy Logic ◽  
Condition Assessment ◽  
Power Transformers

Atomization of Liquids by Means of a Rotating Cup

1950 ◽  
Vol 17 (2) ◽  
pp. 145-153 ◽  
Author(s):  
J. O. Hinze ◽  
H. Milborn
Keyword(s):  
Working Conditions ◽  
Drop Size ◽  
Film Formation ◽  
Angular Speed ◽  
The State ◽  
Experimental Results ◽  
Drop Formation ◽  
Dimensionless Groups ◽  
Different Types ◽  
Centrifugal Action

Abstract Liquid, supplied through a stationary tube to the inner part of a rotating cup widening toward a brim, flows viscously in a thin layer toward this brim and is then flung off, all by centrifugal action. The flow within this layer and the disintegration phenomena occurring beyond the brim have been studied, experimentally as well as theoretically. A formula has been derived for the thickness and for the radial velocity of the liquid layer within the cup, which proved to agree reasonably well with experimental results. Three essentially different types of disintegration may take place around and beyond the edge of the cup designated, respectively, by: (a) the state of direct drop formation; (b) the state of ligament formation; and (c) the state of film formation. Which one of these is realized depends upon working conditions. Transition from state (a) into (b), or of state (b) into state (c) is promoted by an increased quantity of supply, an increased angular speed, a decreased diameter of the cup, an increased density, an increased viscosity, and a decreased surface tension of the liquid. The experimental results have been expressed in relationships between relevant dimensionless groups. For the state of ligament formation a semiempirical relationship has been derived between the number of ligaments and dimensionless groups determining the working conditions of the cup. Results of drop-size measurements made for the state of ligament formation as well as for the state of film formation show that atomization by mere rotation of the cup is much more uniform than commonly achieved with pressure atomizers.

Analysis of the state and prospects of the market of fruit and berry products

2020 ◽  
pp. 37-42
Author(s):  
M.A. Nikolaeva ◽  
A.V. Krokhaleva
Keyword(s):  
The State ◽  
Retail Trade ◽  
Large Share ◽  
Russian Market ◽  
Domestic Production ◽  
Confectionery Products ◽  
Import And Export ◽  
Cis Countries ◽  
A Share

The article considers the state of domestic production of fruit and berry products, their import and export. It is estimated that the production volumes of sugar confectionery products, including fruit and berry products, are almost continuously increasing. Marmalade accounts for a large share of the production of all fruit and berry products. Its share is 49.2%, including chewing marmalade with a share of 24.8%. Imports of these products are gradually decreasing. The assortment of imported fruit and berry products is dominated by ready-made confitures, jams, and fruit butter for retail trade (53%). Exports of these products are increasing from year to year, with exports to the CIS countries, China, and Mongolia dominating. Prospects for the development of the Russian market of fruit and berry products are formulated.

Differential Multipliers for Tourism in Victoria

1997 ◽  
Vol 3 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Guy R. West ◽  
Ari Gamage
Keyword(s):  
Economic Impacts ◽  
Value Added ◽  
The State ◽  
Input Output ◽  
Relative Contribution ◽  
State Economy ◽  
Different Types

This study assesses the significance of different types of tourists to Victoria, Australia, by their relative contribution to the economy. Differential impacts are calculated using an input–output model incorporating marginal household coefficients. The analysis demonstrates that the conventional input–output model can overestimate the flow-on effects to value added, income and employment by a significant amount. It finds that domestic tourists are the largest contributor to the State economy, with day-trippers spending the greatest amount. International tourists rank last in terms of economic impacts on the state.

Inside global financial networks

2018 ◽  
Vol 8 (3) ◽  
pp. 294-299 ◽  
Author(s):  
Laura-Marie Töpfer
Keyword(s):  
Firm Behavior ◽  
Financial System ◽  
The State ◽  
Financial Networks ◽  
Different Types ◽  
Competitive Hierarchies ◽  
Global Financial System

The commentaries on this forum’s anchor article, ‘China’s Integration into the Global Financial System: Toward a State-led Conception of Global Financial Networks’, examine how the state is shaping global financial networks (GFNs). In response to these reviews, this article discusses three common themes that bind the different commentaries: (1) different types of agency, power, and the rise of new actors; (2) the methodology behind studying state-led GFNs; and (3) the structural question of ‘Chinese exceptionalism’ as a mode of capitalism. Overall, this article affirms that the state remains central to our understanding of competitive hierarchies and firm behavior in financial networks.

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