<abstract xmlns="http://www.w3.org/1999/xhtml">The energy efficiency monitoring methods in industry are based on statistical modeling of energy consumption. In the present paper, the widely used method of energy efficiency monitoring “Monitoring and Targeting systems” has been considered, highlighting one of the most important issues — selection of the proper mathematical model of energy consumption. The paper gives a list of different models that can be applied in the corresponding systems. The numbers of criteria that estimate certain characteristics of the mathematical model are represented. The traditional criteria of model adequacy and the “additional” criteria, which allow estimating the model characteristics more precisely, are proposed for choosing the mathematical model of energy consumption in “Monitoring and Targeting systems”. In order to provide the comparison of different models by several criteria simultaneously, an approach based on Data Envelopment Analysis is proposed. Such approach allows providing a more accurate and reliable energy efficiency monitoring.</abstract>

Associate Professor, National Technical University of Ukraine “Kyiv Polytechnic Institute”

Professor, Vilnius Gediminas Technical University, Center for Physical Science and Technology

Associate Professor, Telemark University College,

Ph.D. student, Vilnius Gediminas Technical University, National Technical University of Ukraine “Kyiv Polytechnic Institute”

Selection Methodology of Energy Consumption Model Based on Data Envelopment Analysis

<abstract xmlns="http://www.w3.org/1999/xhtml">Given the fact that the installing costs of an optical ground wire on overhead lines directly depend on its cross-section, which in turn depends on the level of fault current it should withstand, in order to reduce these current values in the optical ground wire, I suggested performing its isolated descents from the end towers of the line with its transition to an optical cable. The research was carried out on the example of a 500 kV overhead line in the National Electric Power Grid. The Method of Symmetrical Components for calculating asymmetrical fault currents was not used; therefore, calculations were carried out on the base of presenting the line as a multi-wire system for the considered case as a five-wire system (optical ground wire, steel ground wire, and three phase wires). Such approach allows taking into account the initial asymmetry of the line parameters and modeling any kind of asymmetrical faults. The analyses of calculated results were performed. The conclusive evidence that the optical ground wire isolated descents from the end towers of the line give the possibility of reducing the level of maximal fault current distribution values in it and therefore its cross section, is presented.</abstract>

The Way of Reducing Current Values in Optical Ground Wires at Asymmetrical Faults on Overhead Transmission Lines

<abstract xmlns="http://www.w3.org/1999/xhtml">This paper is related to an alternative energetics microgrid with a wind generator and a hydrogen energy storage system. The main aim of this research is the development of solutions for effective use of the wind generators in alternative energetics devices, at the same time providing uninterrupted power supply of the critical loads. In this research, it was accepted that the alternative energetics microgrid operates in an autonomous mode and the connection to the conventional power grid is not used. In the case when wind speed is low, the necessary power is provided by the energy storage system, which includes a fuel cell and a tank with stored hydrogen. The theoretical analysis of the storage system operation is made. The possible usage time of the stored hydrogen depends on the available amount of hydrogen and the consumption of the hydrogen by the fuel cell. The consumption, in turn, depends on used fuel cell power. The experimental results suggest that if the wind generator can provide only a part of the needed power, the abiding power can be provided by the fuel cell. In this case, a load filter is necessary to decrease the fuel cell current pulsations.</abstract>

Leading Researcher, Riga Technical University

Alternative Energetics DC Microgrid With Hydrogen Energy Storage System

<abstract xmlns="http://www.w3.org/1999/xhtml">Constructions of meander slow-wave systems with additional shields grounded at different positions are presented. The construction of meander slow-wave systems with additional shields grounded at both edges is investigated in detail. The influence of the main constructive parameters on the electrical characteristics of meander slow-wave systems with additional shields grounded at both edges is evaluated. The main constructive parameters of the investigated system are: the length of the conductor, the width of meander conductor, the width of additional shield, and the width of the gap between adjacent meander conductors.Sonnet® software package, which is based on the method of moments, has been used during the investigation. The results of the influence of constructive parameters to the phase delay time, input impedance, and the width of pass-band of the system are discussed.</abstract>

Researcher, Vilnius Gediminas Technical University

Professor, Vilnius Gediminas Technical University

Associate Professor, Vilnius Gediminas Technical University

Influence Coefficients of Constructive Parameters of Meander Slow-Wave System with Additional Shields

<abstract xmlns="http://www.w3.org/1999/xhtml">Easy usage and integration with various applications made IEEE 802.11 one of the most used technologies these days, both at home and business premises. Over the years, there have been many additional improvements to the 802.11 standards. Nevertheless, the algorithms and Media Access Control (MAC) layer methods are almost the same as in previous Wi-Fi versions. In this paper, a set of methods to improve the total system capacity is proposed – such as efficient transmit power management based on Game Theory with a custom wireless medium protocol. The transmit power management and wireless medium protocol is verified by both simulation and real application scenarios. The results conclude that the capacity of the proposed wireless medium protocol is overall 20 percent higher than the standard 802.11 wireless medium access protocols. Additional TCP Acknowledgment filtering, which was tested together with the proposed wireless medium access protocol, can provide up to 10-percent-higher TCP throughput in high-density scenarios, especially for asymmetrical traffic cases. The conducted research suggests that efficient power management could result in lighter transmit power allocation rules that are currently set by the local regulators for current Wi-Fi devices. Thus, better propagation characteristics and wireless medium management would lead to an overall higher wireless system capacity.</abstract>

Doctoral Student, Vilnius Gediminas Technical University

Assistant Professor, Vilnius Gediminas Technical University

TCP Performance in Multi-Polling Game Theory-Based IEEE 802.11 Networks

AHEAD OF PRINT

Volume 19 (2023): Issue 1 (June 2023)

Volume 18 (2022): Issue 1 (June 2022)

Volume 17 (2021): Issue 1 (June 2021)

Volume 16 (2020): Issue 2 (December 2020)

Volume 16 (2020): Issue 1 (January 2020)

Volume 15 (2019): Issue 2 (December 2019)

Volume 15 (2019): Issue 1 (September 2019)

Volume 14 (2018): Issue 2 (December 2018)

Volume 14 (2018): Issue 1 (July 2018)

Volume 13 (2017): Issue 1 (December 2017)

Volume 12 (2017): Issue 1 (July 2017)

Volume 11 (2016): Issue 1 (December 2016)

Volume 10 (2016): Issue 1 (July 2016)

Volume 9 (2015): Issue 1 (December 2015)

Volume 8 (2015): Issue 1 (July 2015)

Volume 7 (2014): Issue 1 (December 2014)

Volume 6 (2014): Issue 1 (October 2014)

Volume 5 (2014): Issue 1 (May 2014)

Volume 4 (2013): Issue 1 (December 2013)

Volume 3 (2013): Issue 1 (August 2013)

Volume 2 (2013): Issue 1 (April 2013)

Volume 1 (2012): Issue 1 (December 2012)

Electrical, Control and Communication Engineering

The aim of the Journal of Electrical, Control and Communication Engineering of Riga Technical University (RTU-ECCE Journal) is to provide an on-line forum for scientific discussions and feedbacks from the scientific society to particular scientists from all over the world on their later scientific achievements in the below mentioned fields.　The journal considers publication of all authors, but gives preference to the post-conference papers after one of the following events (International Scientific Conferences on Power and Electrical Engineering of Riga Technical University - RTUCON, Workshops on Advances in Information, Electronic and Electrical Engineering – AIEEE, International Doctoral School of Electrical Energy Conversion and Saving Technologies of Riga Technical University, Doctoral School of Energy and Geotechnology of TalTech), as well as the papers recommended by section editors of the journal. The submissions are reviewed, edited and published in the mentioned priority order.  The scope of RTU-ECCE journal includes (but not limited to) the following areas:    Electrical Engineering and Power Electronics:     Electrical machines, Apparatus, Drives, Motion Control and Robotics;    Components, Design and Application of Power Electronic Converters;    Electromagnetic Compatibility and Interference of Electrical Equipment;    Electrical Materials, Reliability and Diagnostics;    Medical and other Bio-contact Electrical Equipment.    Power and Energy Systems:     Power System Control, Automation, Stability and Protection;    Power Quality and Reliability;    Power Plants, Renewable and Distributed Energy Systems;    Power System Planning, Management, Economic Evaluation and Risk Assessment;    Electricity Market;    Smart Grids &amp; Microgrids.    Information Processing in the context of Electrical and Power Engineering     Electronic Circuits and Systems for Control Applications;    Control Theory, Analysis, Simulation and Implementation Software;    Principles of Physical Transmission and Processing of Information, New Interfaces and Protocols.    Microwave Technique and Antennas     Theory, Analysis and Simulation of Microwave Technique;    Software and Experimental Methods Dedicated for Microwave Equipment;    Antennas, Radar Systems and other Microwave Applications.  The editorial board of RTU-ECCE Journal is always open for discussion on the journal topics.   In 2012 the journal Electrical, Control and Communication Engineering separated from the RTU journal series Power and Electrical Engineering. Why subscribe and read  Electrical, Control and Communication Engineering is a peer-reviewed journal providing the latest information in the field of electrical engineering and information technologies. The journal focuses on recent research in electrical and control engineering paying special attention to the reports which have the most significant practical importance.The journal includes a wide range of publications on electrical and electronic equipment, as well as on other means for energy conversion, information processing and transmission purposes.  Why submit  The journal provides highly qualified feedback on the research, as well as international publicity. The editorial board will continuously care about the citation level of the journal.  Rejection Rate   30%   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 