scholarly journals Recycling Heat Losses of an Oil-Immersed Transformer: Feasibility Study

2021 ◽  
Vol 21 (1) ◽  
pp. 48-54
Keyword(s):  
High Efficiency ◽  
Power Transformer ◽  
Heat Losses ◽  
Power Transformers ◽  
Passive Mode ◽  
Active Mode ◽  
Short Circuits ◽  
Definition Of ◽  
The Relationship ◽  
Novel Design

The paper investigates the feasibility of adding a liquid heater to an oil-immersed transformer. It proves that design the high efficiency of power transformers, losses due to idling and short circuits are substantial and are scattered in the environment as heat. The paper proposes a novel design that implements a liquid (coolant) heater to enable the unit not only to convert electricity, but also to generate heat. In order to analyze the feasibility of such heat recycling, the authors have developed an equivalent thermal circuit and a mathematical model thereof. Said heater can operate in two modes. In the passive mode, the coolant it contains only absorbs the heat emitted (lost) by the power transformer. In the active mode, it also receives the heat emitted due to the passage of electric current through the pipes of the heater. The paper further introduces the definition of heater efficiency. Studies have shown that up to 50 % of transformer heat losses can be recycled by heating the coolant in the heater. The paper presents the relationship between utilized heat and transformer losses, as well as heater efficiency as a function of coolant flow rate. The heater efficiency exceeds 90 % in the active mode.

scholarly journals Novel Remanence Determination for Power Transformers Based on Magnetizing Inductance Measurements

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4616
Author(s):  
Chen Wei ◽  
Xianqiang Li ◽  
Ming Yang ◽  
Zhiyuan Ma ◽  
Hui Hou
Keyword(s):  
Numerical Simulations ◽  
Laboratory Experiments ◽  
Power Transformer ◽  
Power Transformers ◽  
Inrush Current ◽  
The Core ◽  
Novel Method ◽  
Simulation Results ◽  
Electro Magnetic ◽  
The Relationship

The remanence (residual flux) in the core of power transformers needs to be determined in advance to eliminate the inrush current during the process of re-energization. In this paper, a novel method is proposed to determine the residual flux based on the relationship between residual flux and the measured magnetizing inductance. The paper shows physical, numerical, and analytical explanations on the phenomenon that the magnetizing inductance decreases with the increase of residual flux under low excitation. Numerical simulations are performed by EMTP (Electro-Magnetic Transient Program) on a 1 kVA power transformer under different amounts of residual flux. The inductance–remanence curves are nearly the same when testing current changes. Laboratory experiments conducted on the same transformer are in line with the numerical simulations. Furthermore, numerical simulation results on a 240 MVA are reported to demonstrate the effectiveness of the proposed method.

scholarly journals Технологические способы ведения взрывных работ, позволяющие безопасно управлять действием взрыва в массиве горных пород

2018 ◽  
pp. 53-57
Author(s):  
S.V. Tishchenko ◽  
G.I. Eremenko ◽  
D.Yu. Malykh
Keyword(s):  
High Efficiency ◽  
Specific Impulse ◽  
Bottom Part ◽  
Air Cavity ◽  
Entire Height ◽  
Borehole Charge ◽  
Definition Of ◽  
The Relationship ◽  
Destruction Of Rocks ◽  
Explosive Destruction

Purpose. The work is devoted to improving the efficiency and safety of the escarpous blasting of rocks by borehole charges of explosives of a new design at iron ore quarries. In the thesis, the features of the process of explosive destruction of rocks by well charges of various designs are investigated. The dependences of their dynamics of explosive destruction on the physicomechanical properties of rocks are established, and the relationship between the distribution of energy of destruction in the medium and the magnitude of the specific impulse of the explosion is determined. Metodology. The obtained regularities of the impulse effect of an explosion associated with the overall energy balance imparted to a destructible medium can serve as a scale for evaluating the effectiveness of the action of well charges exploded simultaneously or through the definition of deceleration. Based on the obtained theoretical and laboratory results, a new design of a downhole charge of explosives with an air cavity in the bottom of the well has been developed. Findings. A feature of this design of the borehole charge is the concentration of the explosion energy in the bottom of the well. The optimal parameters of the air cavity and the location of the initiator relative to it in the technology of blasting have been established. Originality of the work lies in the fact that the conducted industrial tests of a new design of a borehole charge with an air cavity in the bottom part of the well showed its high efficiency. Practical value lies in achieving a reduced specific consumption of explosives. This technological process ensures uniform crushing of the blasted rock mass over the entire height of the ledge and high-quality development of the bottom of the ledge, which opens up real opportunities for the elimination of the re-drilling of the well at the inferior explosive blasting of rocks.

scholarly journals Management of power transformers reliability by technologies of control on resource characteristics of liquid dielectric

2018 ◽  
Vol 58 ◽  
pp. 02007
Author(s):  
Svetlana Vysogorets ◽  
Alexandr Nazarychev ◽  
Ilia Gorec ◽  
Alexey Tadjibaev
Keyword(s):  
Experimental Determination ◽  
Quality Indicators ◽  
Power Transformer ◽  
Liquid Dielectric ◽  
Power Transformers ◽  
Resource Characteristics ◽  
First Time ◽  
The Relationship

The relationship between the resource of a power transformer and the resource characteristics of a liquid dielectric is shown. Determined the key quality indicators, which allow to control the resource of the liquid dielectric. For the first time, “The method of experimental determination of the liquid dielectric resource and measures for its restoration” was developed.

A Solid-State On-Load Tap Changer for the Power Transformers of 10—0.4 kV Distribution Networks

Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 82-90
Author(s):  
Dmitriy I. Panfilov ◽  
◽  
Mikhail G. Astashev ◽  
Aleksandr V. Gorchakov ◽  
◽  
...  
Keyword(s):  
Solid State ◽  
Physical Model ◽  
High Speed ◽  
Power Transformer ◽  
Voltage Control ◽  
Power Transformers ◽  
Control Algorithms ◽  
Load Voltage ◽  
Tap Changer ◽  
Load Tap Changer

The specific features relating to voltage control of power transformers at distribution network transformer substations are considered. An approach to implementing high-speed on-load voltage control of serially produced 10/0.4 kV power transformers by using a solid-state on-load tap changer (SOLTC) is presented. An example of the SOLTC circuit solution on the basis of thyristor switches is given. On-load voltage control algorithms for power transformers equipped with SOLTC that ensure high reliability and high-speed operation are proposed. The SOLTC performance and the operability of the suggested voltage control algorithms were studied by simulation in the Matlab/Simulink environment and by experiments on the SOLTC physical model. The structure and peculiarities of the used simulation Matlab model are described. The SOLTC physical model design and its parameters are presented. The results obtained from the simulating the SOLTC operation on the Matlab model and from the experiments on the SOLTS physical model jointly with a power transformer under different loads and with using different control algorithms are given. An analysis of the experimental study results has shown the soundness of the adopted technical solutions. It has been demonstrated that the use of an SOLTC ensures high-speed voltage control, high efficiency and reliability of its operation, and arcless switching of the power transformer regulating taps without load voltage and current interruption. By using the SOLTC operation algorithms it is possible to perform individual phase voltage regulation in a three-phase 0.4 kV distribution network. The possibility of integrating SOLTC control and diagnostic facilities into the structure of modern digital substations based on the digital interface according to the IEC 61850 standard is noted.

The influence of ultrasound signal parameters on sonoluminescence light intensity

2013 ◽  
Vol 62 (4) ◽  
pp. 605-612
Author(s):  
Marek Szmechta ◽  
Tomasz Boczar ◽  
Dariusz Zmarzły
Keyword(s):  
Acoustic Emission ◽  
Acoustic Waves ◽  
Power Transformer ◽  
Electrical Power ◽  
Partial Discharges ◽  
Research Project ◽  
Insulation Systems ◽  
Secondary Phenomenon ◽  
New Research ◽  
The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

ADMINISTRATIVE AND LEGAL STATUS OF THE CAPITAL OF UKRAINE - THE HERO CITY OF KYIV AS A GUARANTEE OF THE RIGHTS OF CITIZENS OF UKRAINE AND THE TERRITORIAL COMMUNITY OF THE CITY

2017 ◽  
Author(s):  
Oleksii Chepov ◽  
Keyword(s):  
Legal Status ◽  
Modern World ◽  
Legal Regime ◽  
Legal Doctrine ◽  
City Councils ◽  
The Social ◽  
District Management ◽  
Definition Of ◽  
The Relationship ◽  
The City

The qualitative and clear definition of the legal regime of the capital of Ukraine, the hero city of Kyiv, is influenced by its legislative enshrinement, however, it should be noted that discussions are ongoing and one of the reasons for the unclear legal status of the capital is the ambiguity of current legislation in this area. Separation of the functions of the city of Kyiv, which are carried out to ensure the rights of citizens of Ukraine and the functions that guarantee the rights of the territorial community of the city of Kyiv. In the modern world, in legal doctrine and practice, the capital is understood as the capital of the country, which at the legislative level received this status and, accordingly, is the administrative and political center of the state, which houses the main state bodies and diplomatic missions of other states. It is the identification of the boundaries of the relationship between the competencies of state administrations and local self-government, in practice, often raises questions about their delimitation and ways of regulatory solution. Peculiarities of local self-government in Kyiv city districts are defined in the provisions of the Law on the Capital, which reveal the norms of the Constitution in these legal relations, according to which the issue of organizing district management in cities belongs to city councils. Likewise, it is unregulated by law to lose the particularity of the legal status of the territory of the city. It should be emphasized that the subject of administrative-legal relations is not a certain administrative-territorial entity, but the social group is designated - the territorial community of the city of Kiev, kiyani. Thus, the provisions on the city of Kyiv partially ignore the potential of the territorial community.

Compliance and Conflict of Value in Public Policy Implementation: Comparison between the New Order and the Reformation Era

2018 ◽  
Vol 2 (2) ◽  
pp. 99 ◽  
Author(s):  
Dwiyanto Indiahono ◽  
Erwan Purwanto ◽  
Agus Pramusinto
Keyword(s):  
Public Policy ◽  
Policy Implementation ◽  
Local Level ◽  
Group Discussion ◽  
New Order ◽  
The Reformation ◽  
Public Policy Implementation ◽  
Definition Of ◽  
Conflict Of Value ◽  
The Relationship

This research aims to examine differences in the relationship of bureaucratic and political officials during the New Order (Soeharto’s era) and the Reformation (post-Soeharto) era within the arena of public policy implementation. This is a matter of importance given that there is a change in relations between the two from integration in the New Order to bureaucratic impartiality in the Reformation Era. This study attempts to answer the question: How were the relations of bureaucratic and political officials in the implementation of local level public policy during the New Order and the Reformation Era? A qualitative research has been conducted in Tegal Municipality using the following data collection techniques: interview, focus group discussion, documentation, and observation. Tegal Municipality was selected as the study location because of the unique relationship shown between the mayor and the bureaucracy. Its uniqueness lies in the emergence of bureaucratic officials who dare to oppose political officials, based on their convictions that bureaucratic/public values should be maintained even if it means having to be in direct conflict with political officials. This research indicates that the relationship between bureaucratic and political officials in the arena of local level policy implementation during the New Order was characterized as being full of pressure and compliance, whereas during the Reformation Era bureaucrats have the audacity to hinder policy implementation. Such audacity to thwart policies is considered to have developed from a stance that aims to protect public budget and values in policies. The occurring conflict of values here demonstrates a dichotomy of political and bureaucratic officials that is different from the prevailing definition of politics-administration dichotomy introduced at the onset of Public Administration studies.

The Concept of Europeanization and Possibilities of its Application to the Analysis of Ukraine-EU Relations

2017 ◽  
pp. 149-160
Author(s):  
Natalia Popova
Keyword(s):  
European Integration ◽  
Theoretical Research ◽  
Member States ◽  
External Governance ◽  
Definition Of ◽  
The Relationship ◽  
Eu Studies ◽  
The Eu

The concept of Europeanization has become quite fashionable in EU studies in recent years. It is often used for the analysis of the relations between the EU and non-member states. The aim of the article is to examine the possibilities of its application in explaining the relationship between the EU and Ukraine. The structure of the article is as follows: firstly, the concept of Europeanization is defined considering such two disputable issues as distinguishing among concepts of Europeanization and European integration as well as Europeanization and EU-ization. Next, the evolution of the theoretical research of Europeanization and definition of this concept are analyzed. Two main mechanisms of Europeanization (conditionality and socialization) are examined. The author considers main approaches to the analysis of the "external" Europeanization emphasizing the concept of "external governance". Three groups of factors which influence the effectiveness of Europeanization are briefly analyzed. And finally, the peculiarities of application of the Europeanization concept to the Ukraine-EU relations are outlined. Keywords: EU, Ukraine, Europeanization, EU-ization, ‘external’ Europeanization, conditionality, socialization, concept of ‘external governance’

О вопросах фольклоризма в письменной литературе

2019 ◽  
pp. 31-33
Author(s):  
Суусар Искендерова
Keyword(s):  
Modern Science ◽  
Folk Songs ◽  
Point Of View ◽  
The Past ◽  
Scientific Term ◽  
Literature Culture ◽  
Definition Of ◽  
The Relationship

Аннотация: Исследование проблемы фольклоризма является наиболее актуальной в современной науке о фольклоре. На разных этапах развития художественной литературы для формирования индивидуального творчества писателя особенно значимым становятся фольклорные жанры, сюжетные мотивы и художественные средства. В статье рассматривается связь письменной литературы и фольклора, особенно точка зрения проблеме фольклоризма в прошлом и их анализ. Термин «фольклоризм» начал использоваться советскими исследователями учеными как научный термин еще в 1930-х гг. Термин «фольклоризм» используется в различных сферах культуры, а в этой статье мы будем рассматривать в литературе. Несмотря на то, что на протяжении многих лет этот вопрос изучается литературоведами, фольклористами, все -таки нет единого теоретического определения понятия. Ключевые слова: фольклор, фольклоризм, литература, культура, письменная литература, художественная литература, оседлый народ, пословицы и поговорки, фольклорные песни. Аннотация: Көркөм адабияттын өнүгүүсүнүн ар кайсы баскычтарында сүрөткердин жеке чыгармачылыгынын калыптанышы үчүн фольклордук жанрлар, сюжеттер, мотивдер жана көркөм каражаттар айрыкча мааниге ээ. Макалада жазма адабият менен фольклордук карым-катышы, айрыкча фольклоризм маселеси жөнүндө мурдагы көз караштарга кайрылып, аларга талдоо жүргүзүү менен бирге автор өз байкоолорунда келтирет. “Фольклоризм” деген илимий термин 1930-жылы баштап колдонула баштаган. “Фольклоризм” термини маданияттын түрдүү сфераларында кеңири колдо- нулат, бул жерде адабияттагы колдонулушун каралат. Макалада адабий материал менен фольклордук байланышын терең түшүнүү үчүн адабий фольклоризм маселесинин талаштуу жактары каралат. Түйүндүү сөздөр: фольклор, фольклоризм, адабият, маданият, жазма адабият, көркөм адабият, көчмөн калк, макал-лакап, фольклордук ырлар. Annotation: The study of the problem of folklore is the most relevant in the modern science of folklore. At various stages in the development of fiction, folklore genres, plot motifs, and artistic means become especially significant for the formation of the writer's individual creativity. The article examines the relationship between written literature and folklore, especially the point of view of the problem of folklorism in the past and their analysis. The term "folklorism" began to be used by Soviet scholars as a scientific term back in the 1930s. The term "folklorism" is used in various fields of culture, and in this article we will consider in the literature. Despite the fact that for many years this issue has been studied by literary scholars, folklorists, all the same there is no single theoretical definition of the concept. Keywords: folklore, folklorism, literature, culture, written literature, fiction, settled people, proverbs and sayings, folk songs.

Sifat-sifat Submodul Prima dan Submodul Prima Lemah

2020 ◽  
Vol 2 (2) ◽  
pp. 183
Author(s):  
Hisyam Ihsan ◽  
Muhammad Abdy ◽  
Samsu Alam B
Keyword(s):  
Prime Ideal ◽  
Literature Study ◽  
Prime Submodules ◽  
Unitary Module ◽  
Prime Submodule ◽  
Definition Of ◽  
The Relationship

Penelitian ini merupakan penelitian kajian pustaka yang bertujuan untuk mengkaji sifat-sifat submodul prima dan submodul prima lemah serta hubungan antara keduanya. Kajian dimulai dari definisi submodul prima dan submodul prima lemah, selanjutnya dikaji mengenai sifat-sifat dari keduanya. Pada penelitian ini, semua ring yang diberikan adalah ring komutatif dengan unsur kesatuan dan modul yang diberikan adalah modul uniter. Sebagai hasil dari penelitian ini diperoleh beberapa pernyataan yang ekuivalen, misalkan  suatu -modul ,  submodul sejati di  dan ideal di , maka ketiga pernyataan berikut ekuivalen, (1)  merupakan submodul prima, (2) Setiap submodul tak nol dari   -modul memiliki annihilator yang sama, (3) Untuk setiap submodul  di , subring  di , jika berlaku  maka  atau . Di lain hal, pada submodul prima lemah jika diberikan  suatu -modul,  submodul sejati di , maka pernyataan berikut ekuivalen, yaitu (1) Submodul  merupakan submodul prima lemah, (2) Untuk setiap , jika  maka . Selain itu, didapatkan pula hubungan antara keduanya, yaitu setiap submodul prima merupakan submodul prima lemah.Kata Kunci: Submodul Prima, Submodul Prima Lemah, Ideal Prima. This research is literature study that aims to examine the properties of prime submodules and weakly prime submodules and the relationship between  both of them. The study starts from the definition of prime submodules and weakly prime submodules, then reviewed about the properties both of them. Throughout this paper all rings are commutative with identity and all modules are unitary. As the result of this research, obtained several equivalent statements, let  be a -module,  be a proper submodule of  and  ideal of , then the following three statetments are equivalent, (1)  is a prime submodule, (2) Every nonzero submodule of   -module has the same annihilator, (3) For any submodule  of , subring  of , if  then  or . In other case, for weakly prime submodules, if given  is a unitary -module,  be a proper submodule of , then the following statements are equivalent, (1)  is a weakly prime submodule, (2) For any , if  then . In addition, also found the relationship between both of them, i.e. any prime submodule is weakly prime submodule.Keywords: Prime Submodules, Weakly Prime Submdules, Prime Ideal.

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