scholarly journals Estimating the Impact of Arc Furnaces on the Quality of Power in Supply Systems

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1462
Author(s):  
Zbigniew Łukasik ◽  
Zbigniew Olczykowski

Arc furnaces, due to their high unit power and load nature, belong to the receivers affecting the power quality. A dynamically changing electric arc is the main source of disturbances generated by arc devices. This current article presents the results of model tests of disturbances caused by arc furnaces. It also presents the attempts to estimate the power supply conditions for arc furnaces, so that they do not generate unacceptable disturbances to the power system. Various models of the electric arc are proposed. The values of the elements making up the furnace supply system were based on actual parameters. In these networks, measurements of electricity quality indicators were carried out, which allowed us to refer to the obtained results of model tests with the real values. Accordingly, to the real conditions, the values of the short-circuit power of the network and the power of furnace transformers were also adopted in the tests.

Author(s):  
Liu Yang ◽  
Qinyue Tan ◽  
Di Xiong ◽  
Zhengguang Liu

The overrun of transient power quality index caused by the large-capacity electric arc furnace (EAF) has become a prominent problem affecting the safe and stable operation of the power system. (1) In this paper, the relationship between arc furnace volt-age and current is derived based on the different stages of arc combustion, and the random variation of chaotic phenomenon of the arc voltage are simulated. Established an EAF model suitable for the study of transient power quality problems. (2) Take 50t AC EAF as an example to analyze the reactive power impact and the influence on the point of common coupling (PCC) voltage caused by the three-phase short circuit of the electrode. The results show that the experimental results are consistent with the theoretical analysis, verifying the correctness and effectiveness of the model. (3) When the three-phase short-circuit occurs, the reactive power impact is nearly 6 times that of normal operation, the short-circuit current is 2.66 times that of normal operation, and the effective value of the PCC voltage has dropped by 40.37%, which provides a theoretical basis for real-time compensation of impulsive reactive power and improvement of the transient power quality of the EAF.


1973 ◽  
Vol 17 (3) ◽  
pp. 239-250 ◽  
Author(s):  
Leslie R. Eastcott

This paper reviews some of the salient research into the complex issue of the impact of class size on the quality of teaching and learning. It describes the general attitude of the teaching profession towards class size and discusses some of the claims made regarding the influence of the variable on teaching and learning. Some evidence is presented to illustrate the nature of the profession's stand on the issue. It is acknowledged that the real impact of class size is much less clear than is implied by the normal assertions regarding its importance, and some of the important literature is examined to illustrate this point. From the discussion several suggestions emerge for desirable procedures in the further investigation of this area.


Author(s):  
Олена Сергіївна Юрченко

Formulation of the problem. Based on the study, the prerequisites, features and components of the formation of accounting policies in the context of business continuity are revealed. The purpose of the article is to substantiate the theoretical and methodological and organizational provisions of accounting policy formation in the context of the implementation of the concept of continuity. The object of research is the process of formation of accounting policy and its impact on the quality of corporate financial reporting information. Methods used in the study: scientific knowledge, method of generalization, comparison, logical - meaningful, methods of induction and deduction. The main hypothesis is that the formation of accounting policies aimed at determining the regulations of accounting and reporting from the standpoint of reflecting complete and reliable information about the real value of assets and liabilities will help reconcile the interests of all stakeholders. Presenting main material. The article identifies the prerequisites, directions and elements of the formation of accounting policies on the principle of continuity of enterprises. Provisions on the development of theoretical and methodological foundations for the formation of accounting policies of enterprises on the basis of risk-oriented approach are revealed. The necessity of valuation of assets and liabilities according to the criteria: fair, discounted and market value of enterprises is substantiated and the methodological support of valuation of financial instruments in accounting is revealed. Originality and practical significance are proposals for the formation of methodological and organizational support and recommendations for the measurement of assets and liabilities at fair value in order to improve the quality of financial statements. Research findings. The formation of accounting policy in the context of the principle of continuity is based on the requirements of International Accounting Standards and National Accounting Standards and depends on the needs of management, methods and techniques of accounting. In the process of developing an accounting policy, it is necessary to take into account the information needs of various stakeholders to disclose information in corporate financial statements. The introduction of theoretical and methodological provisions for the formation of elements of accounting policy on the principle of continuity will meet the information needs of different users, improve the quality of financial reporting and assess the impact of accounting policies on the real value of enterprises in the future.


2018 ◽  
Vol 59 ◽  
pp. 00010
Author(s):  
Robert Nowak ◽  
Anna Imperowicz-Pawlaczyk

The main purpose of this paper is to indicate the impact of changes in the quality of groundwater intakes on the functioning of rural water supply systems. In particular, the important factors for the groundwater quality in rural areas have been presented. Results of research on the quality parameters of groundwater, obtained in 2012 ÷ 2016 for selected small water intakes in north-western Poland, were presented. The quality of groundwater in the subsequent analyzed years was deteriorating. There was an increase in the content of iron and manganese compounds, ammonium ions, as well as the presence of bacteriological contaminants in test water samples. For these reasons, problems with providing the receivers with water of appropriate quality parameters have been reported in described rural intakes. The paper is an attempt to show the relationship between the type and magnitude of changes in the quality of groundwater and the efficiency of the treatment plant. In addition, pro-quality activities undertaken by local water companies were emphasized.


2020 ◽  
Vol 6 (2) ◽  
pp. 97-103
Author(s):  
Yuriy Varetsky ◽  

The practice of operating industrial power supply systems containing filter circuits has shown that filter tuning can have a significant impact on filter performance. On the basis of simulations of a real power supply system carried out by the Matlab / Simulink package, the results of a study of the impact of filter manufacturing tolerances on the filter transients under transformer energizing are presented. The most severe transients are observed for filter circuits in the power supply systems of electric arc furnaces due to frequently repeated operating energizing furnace transformers. This article summarizes the analysis of overvoltages on capacitors and reactors for various configurations of the filter circuit, arising during energizing the arc furnace transformer, taking into account the possible detuning of the filters.


2022 ◽  
pp. 1-1
Author(s):  
Slobodan Bulatović

The quality of common open public spaces is conditioned, among other things, by the layout and characteristics of the facilities located in their immediate vicinity, but also by the functions and contents, equipment and materialization of the ground floor of those facilities. For this reason, interventions on existing facilities and the construction of new ones around common open public spaces can positivelyor negatively affect the quality of these areas. The construction of New Belgrade began in 1948 and continues today. In the area of New Belgrade, the network of common open public spaces covers more than 50% of the total area of the municipality. Initially, the blocks in New Belgrade were built on the basis of a unique planning solution. The transformation of the blocks began in the 1990s in the post-socialist period, when it became possible to change the legal regulations and enable a greater participation of private investments in the processes of reconstruction and new construction. In order to determine the real impact of the reconstruction of mega blocks on the quality of common open public spaces, this paper will present the criteria for determining the quality of these spaces. The criteria will help to examine the differences between the quality of common open public spaces within a block that has had frequent interventions and one where there have been no significant interventions over the last few decades. The conclusions should provide an answer as to whether and to what extent spatial interventions affect the quality of common open public spaces.


Author(s):  
Irina Lyubchenko

The influence of sources of reactive power on the quality of electricity on the tires of non-traction consumers who receive power from the two-wire-rail line in the event of a short circuit in the contact network is studied. The results show that the use of sources of reactive power contributes to the maintenance of voltage on the substation tires, significantly reducing the coefficient of asymmetry in the reverse sequence.


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