Energies

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14 pages, 2927 KiB

Open AccessArticle

Application of an Artificial Neural Network for Measurements of Synchrophasor Indicators in the Power System

by Malgorzata Binek, Andrzej Kanicki and Pawel Rozga

Energies 2021, 14(9), 2570; https://doi.org/10.3390/en14092570 - 30 Apr 2021

Cited by 2 | Viewed by 1881

Dynamic phenomena in electric power systems require fast and accurate algorithms for processing signals. The processing results include synchrophasor parameters, e.g., varying amplitude, phase or frequency of sinusoidal voltage or current signals. This paper presents a novel estimation method of synchrophasor parameters that [...] Read more.

Dynamic phenomena in electric power systems require fast and accurate algorithms for processing signals. The processing results include synchrophasor parameters, e.g., varying amplitude, phase or frequency of sinusoidal voltage or current signals. This paper presents a novel estimation method of synchrophasor parameters that comply with the requirements of IEEE/IEC standards. The authors analyzed an algorithm for measuring the phasor magnitude by means of a selected artificial neural network (ANN), an algorithm for estimating the phasor phase and frequency that makes use of the zero-crossing method. The original components of the presented approach are: the method of the synchrophasor magnitude estimation by means of a suitably trained and applied radial basic function (RBF); the idea of using two algorithms operating simultaneously to estimate the synchrophasor magnitude, phase and frequency that apply identical calculation methods are different in that the first one filters the input signal using the FIR filter and the second one operates without any filter; and the algorithm calculating corrections of the phase shift between the input and output signal and the algorithm calculating corrections of the magnitude estimation. The error results obtained from the applied algorithms were compared with those of the quadrature filter method and the ones presented in literature, as well as with the permissible values of the errors. In all cases, these results were lower than the permissible values and at least equal to the values found in the literature. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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16 pages, 8023 KiB

Open AccessArticle

Operation of the Prototype Device for Induction Heating of Railway Turnouts at Various Operating Frequencies

by Robert Żelazny, Paweł Jabłoński and Tomasz Szczegielniak

Energies 2021, 14(2), 476; https://doi.org/10.3390/en14020476 - 18 Jan 2021

Cited by 5 | Viewed by 3347

Abstract

Devices for electric heating of railroad turnouts are elements of the railway infrastructure protecting railroad turnouts against blocking them by snow and ice in winter. They often operate based on the principle of resistance heating but other solutions are also emerging. In this [...] Read more.

Devices for electric heating of railroad turnouts are elements of the railway infrastructure protecting railroad turnouts against blocking them by snow and ice in winter. They often operate based on the principle of resistance heating but other solutions are also emerging. In this paper, one of such new solutions using the phenomenon of electromagnetic induction was presented and tested under various conditions. In comparison with traditional resistive heaters, the inductive ones offer heat distribution directly to ice and snow without intermediation of rails. Moreover, they can use a wide range spectrum of frequency to shorten the melting time. The resistive and inductive devices were tested with respect to melting time, temperatures and energy consumption. It follows that the induction-based device offers much lower energy consumption at a level of 30%–60% of that by resistive heater. The details depend on frequency used, initial temperature and number of induction devices of action assumed equivalent to the resistive one. Inductive heating of turnouts also offers shorter times of operation, which are obtained for frequencies in the range 40–70 kHz. The inductive device was also tested with respect to magnetic field levels around it to assess its possible influence on nearby infrastructure. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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18 pages, 5434 KiB

Open AccessArticle

The Impact of the Selection of Exogenous Variables in the ANFIS Model on the Results of the Daily Load Forecast in the Power Company

by Janusz Sowinski

Energies 2021, 14(2), 345; https://doi.org/10.3390/en14020345 - 9 Jan 2021

Cited by 10 | Viewed by 2899

Abstract

Forecasting of daily loads is crucial for the Distribution System Operators (DSO). Contemporary short-term load forecasting models (STLF) are very well recognized and described in numerous articles. One of such models is the Adaptive Neuro-Fuzzy Inference System (ANFIS), which requires a large set [...] Read more.

Forecasting of daily loads is crucial for the Distribution System Operators (DSO). Contemporary short-term load forecasting models (STLF) are very well recognized and described in numerous articles. One of such models is the Adaptive Neuro-Fuzzy Inference System (ANFIS), which requires a large set of historical data. A well-recognized issue both for the ANFIS and other daily load forecasting models is the selection of exogenous variables. This article attempts to verify the statement that an appropriate selection of exogenous variables of the ANFIS model affects the accuracy of the forecasts obtained ex post. This proposal seems to be a return to the roots of the Polish econometrics school and the use of the Hellwig method to select exogenous variables of the ANFIS model. In this context, it is also worth asking whether the use of the Hellwig method in conjunction with the ANFIS model makes it possible to investigate the significance of weather variables on the profile of the daily load in an energy company. The functioning of the ANFIS model was tested for some consumers exhibiting high load randomness located within the area under supervision of the examined power company. The load curves featuring seasonal variability and weekly similarity are suitable for forecasting with the ANFIS model. The Hellwig method has been used to select exogenous variables in the ANFIS model. The optimal set of variables has been determined on the basis of integral indicators of information capacity H. Including an additional variable, i.e., air temperature, has also been taken into consideration. Some results of ex post daily load forecast are presented. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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17 pages, 4038 KiB

Open AccessArticle

Application of Genetic Algorithm Elements to Modelling of Rotation Processes in Motion Transmission Including a Long Shaft

by Andriy Chaban, Marek Lis, Andrzej Szafraniec and Radoslaw Jedynak

Energies 2021, 14(1), 115; https://doi.org/10.3390/en14010115 - 28 Dec 2020

Cited by 13 | Viewed by 2218

Abstract

Genetic algorithms are used to parameter identification of the model of oscillatory processes in complicated motion transmission of electric drives containing long elastic shafts as systems of distributed mechanical parameters. Shaft equations are generated on the basis of a modified Hamilton–Ostrogradski principle, which [...] Read more.

Genetic algorithms are used to parameter identification of the model of oscillatory processes in complicated motion transmission of electric drives containing long elastic shafts as systems of distributed mechanical parameters. Shaft equations are generated on the basis of a modified Hamilton–Ostrogradski principle, which serves as the foundation to analyse the lumped parameter system and distributed parameter system. They serve to compute basic functions of analytical mechanics of velocity continuum and rotational angles of shaft elements. It is demonstrated that the application of the distributed parameter method to multi-mass rotational systems, that contain long elastic elements and complicated control systems, is not always possible. The genetic algorithm is applied to determine the coefficients of approximation the system of Rotational Transmission with Elastic Shaft by equivalent differential equations. The fitness function is determined as least-square error. The obtained results confirm that application of the genetic algorithms allow one to replace the use of a complicated distributed parameter model of mechanical system by a considerably simpler model, and to eliminate sophisticated calculation procedures and identification of boundary conditions for wave motion equations of long elastic elements. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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21 pages, 1703 KiB

Open AccessArticle

Energy Dependencies in Li-Ion Cells and Their Influence on the Safety of Electric Motor Vehicles and Other Large Battery Packs

by Andrzej Erd and Jozef Stoklosa

Energies 2020, 13(24), 6738; https://doi.org/10.3390/en13246738 - 21 Dec 2020

Cited by 8 | Viewed by 2336

Abstract

For this work, the specific heat value of a Li-ion cell was determined experimentally as if it were a homogeneous body. The heat absorbed in the cell was compared with the amount of energy contained in the charged cell. It was found that [...] Read more.

For this work, the specific heat value of a Li-ion cell was determined experimentally as if it were a homogeneous body. The heat absorbed in the cell was compared with the amount of energy contained in the charged cell. It was found that a fully charged cell poses a risk of spontaneous combustion in the event of the release of electrical energy. On the basis of literature research, the combustion process of a lithium cell has been described. The formula was derived for the value of the state of charge that does not pose a risk of self-ignition. In view of the existing threats, the currently used protection against cell damage and tests to demonstrate the safety of cells were analyzed. It has been indicated that currently used battery management systems do not guarantee the safety in a state of developing thermal runaway process. A new active way of protecting cells in a battery has been proposed, consisting in sectoral discharge of cells. The use of this solution would be important for the improvement of fire safety in the automotive industry as well as in mining and in the construction of energy storage. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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21 pages, 11672 KiB

Open AccessArticle

Analytical-Numerical Approach to the Skin and Proximity Effect in Lines with Round Parallel Wires

by Paweł Jabłoński, Dariusz Kusiak and Tomasz Szczegielniak

Energies 2020, 13(24), 6716; https://doi.org/10.3390/en13246716 - 19 Dec 2020

Cited by 5 | Viewed by 2799

Abstract

Power and communication lines with round wires are often used in electrical engineering. The skin and proximity effects affect the current density distribution and increase resistances and energy losses. Many approaches were proposed to calculate the effects and related quantities. One of the [...] Read more.

Power and communication lines with round wires are often used in electrical engineering. The skin and proximity effects affect the current density distribution and increase resistances and energy losses. Many approaches were proposed to calculate the effects and related quantities. One of the simplest approximate closed solutions neglects the dimensions of neighboring wires. In this paper, a solution to this problem is proposed based on the method of successive reactions. In this context, the solution with substitutive filaments is considered as the first approximation of the true solution. Several typical arrangements of wires in single-phase communication lines or three-phase bus ducts are considered to detect the limits of applicability of the first approximation. The error of the first approximation grows with wire radius to skin depth ratio and wire radius to wire spacing ratio. When the wire radius to skin depth ratio is up to 1, and the gap between the wires is above the wire radius, the error is at a level of 1%. However, lowering the distance and/or skin depth leads to a much larger error in the first approximation. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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Graphical abstract

17 pages, 3146 KiB

Open AccessArticle

Mathematical Modeling of Transient Processes in Magnetic Suspension of Maglev Trains

by Andriy Chaban, Zbigniew Lukasik, Marek Lis and Andrzej Szafraniec

Energies 2020, 13(24), 6642; https://doi.org/10.3390/en13246642 - 16 Dec 2020

Cited by 8 | Viewed by 2948

Abstract

On the basis of a generalized interdisciplinary method that consists of a modification of Hamilton–Ostrogradski principle by expanding the Lagrange function with two components that address the functions of dissipation energy and the energy of external conservative forces, a mathematical model is presented [...] Read more.

On the basis of a generalized interdisciplinary method that consists of a modification of Hamilton–Ostrogradski principle by expanding the Lagrange function with two components that address the functions of dissipation energy and the energy of external conservative forces, a mathematical model is presented of an electromechanical system that consists of the force section of a magneto-levitation non-contact maglev suspension in a prototype traction vehicle. The assumption that magnetic potential hole, generated naturally by means of cryogenic equipment, is present in the levitation suspension, serving to develop the model system. Contrary to other types of magnetic cushion train suspensions, for instance, maglev–Shanghai or Japan–maglev, this suspension does not need a complicated control system, and levitation is possible starting from zero train velocity. As high-temperature superconductivity can be generated, the analysis of levitation systems, including the effect of magnetic potential holes, has become topical. On the basis of the model of a prototype maglev train, dynamic processes are analyzed in the levitation system, including the effect of the magnetic potential hole. A system of ordinary differential equations of the dynamic state is presented in the normal Cauchy form, which allows for their direct integration by both explicit and implicit numerical methods. Here, the results of the computer simulations are shown as figures, which are analyzed. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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29 pages, 24218 KiB

Open AccessArticle

Application of the Motion Capture System to Estimate the Accuracy of a Wheeled Mobile Robot Localization

by Sebastian Dudzik

Energies 2020, 13(23), 6437; https://doi.org/10.3390/en13236437 - 5 Dec 2020

Cited by 18 | Viewed by 3702

Abstract

The paper presents research on methods of a wheeled mobile robot localization using an optical motion capture system. The results of localization based on the model of forward kinematics and odometric measurements were compared. A pure pursuit controller was used to control the [...] Read more.

The paper presents research on methods of a wheeled mobile robot localization using an optical motion capture system. The results of localization based on the model of forward kinematics and odometric measurements were compared. A pure pursuit controller was used to control the robot’s behaviour in the path following tasks. The paper describes a motion capture system based on infrared cameras, including the calibration method. In addition, a method for determining the accuracy of robot location using the motion capture system, based on the Hausdorff distance, was proposed. As a result of the research it was found that the Hausdorff distance is very useful in determining the accuracy of localization of wheeled robots, especially those described by differential drive kinematics. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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21 pages, 4126 KiB

Open AccessArticle

Methodology and Software Tool for Energy Consumption Evaluation and Optimization in Multilayer Transport Optical Networks

by Krzysztof Przystupa, Mykola Beshley, Mykola Kaidan, Volodymyr Andrushchak, Ivan Demydov, Orest Kochan and Daniel Pieniak

Energies 2020, 13(23), 6370; https://doi.org/10.3390/en13236370 - 2 Dec 2020

Cited by 4 | Viewed by 2608

Abstract

In communication networks, the volume of traffic, the number of connected devices and users continues to grow. As a result, the energy consumption generated by the communication infrastructure has become an important parameter that needs to be carefully considered and optimized both when [...] Read more.

In communication networks, the volume of traffic, the number of connected devices and users continues to grow. As a result, the energy consumption generated by the communication infrastructure has become an important parameter that needs to be carefully considered and optimized both when designing the network and when operating it in real-time. In this paper, the methodology of calculation of complex parameters of energy consumption for transport telecommunication networks is proposed. Unlike the known techniques, the proposed methodology takes into account heterogeneity and multilayer networks. It also takes into account the energy consumption parameter during the downtime of the network equipment in the process of processing the service data blocks, which is quite an important task for improving the accuracy of energy consumption at the stage of implementing the energy-saving network. We also developed simulation software to estimate and manage the energy consumption of the optical transport network using the LabVIEW environment. This software tool allows telecommunication network designers to evaluate energy consumption, which allows them to choose the optimal solution for the desired projects. The use of electro-and acousto-optical devices for optical transport networks is analyzed. We recommended using electro-optical devices for optical modulators and acousto-optical devices for optical switches. The gain from using this combination of optical devices and the parameter of r_ij electro-optical coefficient and M₂ acousto-optical quality parameter found in the paper is about 36.1% relative to the complex criterion of energy consumption. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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20 pages, 5414 KiB

Open AccessArticle

An MPPT Control of a PMSG-Based WECS with Disturbance Compensation and Wind Speed Estimation

by Janusz Baran and Andrzej Jąderko

Energies 2020, 13(23), 6344; https://doi.org/10.3390/en13236344 - 1 Dec 2020

Cited by 33 | Viewed by 5783

Abstract

The paper presents simulation research on a variable structure control scheme of a small variable-speed fixed-pitch wind energy conversion system (WECS) with a three-phase permanent magnet synchronous generator (PMSG) in variable wind conditions. The WECS is connected to a power grid through two [...] Read more.

The paper presents simulation research on a variable structure control scheme of a small variable-speed fixed-pitch wind energy conversion system (WECS) with a three-phase permanent magnet synchronous generator (PMSG) in variable wind conditions. The WECS is connected to a power grid through two back-to-back voltage source converters (VSCs) with a DC link. The presented control algorithm is based on feedforward compensation of the wind turbine aerodynamic torque estimated using a linear disturbance observer (DOB). The torque estimate is employed to determine the effective wind speed, required for setting the reference angular speed, using numerical zero search of a nonlinear function. The simulation model, built in the Matlab/Simulink environment using the Simscape Electrical toolbox, includes the field-oriented control of the PMSG via the machine VSC, performed by cascaded angular velocity and current/torque PI controllers, as well as synchronization with the grid and the reactive power control via the grid VSC. The presented results are focused on the performance of the proposed control in the maximum power point tracking (MPPT) operating region of the WECS for various wind speed profiles. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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17 pages, 5554 KiB

Open AccessArticle

Use of an Artificial Neural Network to Assess the Degree of Training of an Operator of Selected Devices Used in Precision Agriculture

by Karolina Trzyniec and Adam Kowalewski

Energies 2020, 13(23), 6329; https://doi.org/10.3390/en13236329 - 30 Nov 2020

Cited by 5 | Viewed by 1746

Abstract

The article concerns the issue of automatic recognition of the moment of achieving the desired degree of training of an operator of devices used in precision agriculture. The aim of the research was to build a neural model that recognizes when an operator [...] Read more.

The article concerns the issue of automatic recognition of the moment of achieving the desired degree of training of an operator of devices used in precision agriculture. The aim of the research was to build a neural model that recognizes when an operator has acquired the skill of operating modern navigation on parallel strips used in precision agriculture. To conduct the test, a standard device to assist the operator in guiding the machine along given paths, eliminating overlaps, was selected. The thesis was proven that the moment of operator training (meaning driving along designated paths with an accuracy of up to eight centimeters) can be automatically recognized by a properly selected artificial neural network. This network was learned on the basis of data collected during the observation of the operator training process, using a criterion defined by experts. The data collected in the form of photos of the actual and designated route was converted into numerical data and entered into the network input. The output shows the binary evaluation of the trip. It has been shown that the developed neural model will allow the determining of the moment when operators acquire the skills to drive a vehicle along the indicated path and thus shorten the training time. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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13 pages, 2043 KiB

Open AccessArticle

Assessment of the Electromagnetic Field Exposure during the Use of Portable Radios in the Context of Potential Health Effects

by Jarosław Kieliszek, Joanna Wyszkowska, Jaromir Sobiech and Robert Puta

Energies 2020, 13(23), 6276; https://doi.org/10.3390/en13236276 - 28 Nov 2020

Cited by 8 | Viewed by 1980

Abstract

The paper presents research on the electromagnetic hazards related to the flow of electric currents throughout the bodies of employees using portable radios. The values often exceed established limits, which may lead to potential dysfunctions of the body and affect the safety of [...] Read more.

The paper presents research on the electromagnetic hazards related to the flow of electric currents throughout the bodies of employees using portable radios. The values often exceed established limits, which may lead to potential dysfunctions of the body and affect the safety of performed professional duties. The measurements of the electric field (E-field) distribution of a typical commercial portable radio, the limb contact current calculations, and the computer simulations determining a specific absorption rate (SAR) were supplemented with pilot neurophysiological tests. The assessment indicated a large spatial variability of the E-field strength around the devices. The head of the operator and the hand holding the radio were often in the electromagnetic field (EMF), which exceeded the established limits. The calculated SAR values ranged within the permitted limits. The conducted neurophysiological tests showed no effects of EMF exposure in comparison to the control group. The assessment of exposure to the EMF using a portable radio is initially performed by analyzing external measures: both computer simulations and measurements of workers’ limb currents. The SAR values exclude thermal effects; however, they do not eliminate potential neuromuscular effects. More neurophysiological tests are needed to obtain a broader picture of possible health effects. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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17 pages, 574 KiB

Open AccessArticle

Improving the Quality of Electricity in Installations with Mixed Lighting Fittings

by Tomasz Popławski, Marek Kurkowski and Jarosław Mirowski

Energies 2020, 13(22), 6017; https://doi.org/10.3390/en13226017 - 18 Nov 2020

Cited by 7 | Viewed by 2092

Abstract

The issues that are presented in the article concern the broadly understood parameters of the operation of lighting fixtures in mixed systems and the improvement of the quality of electricity, considered in two aspects: as receivers of the energy consumed, determining and generating [...] Read more.

The issues that are presented in the article concern the broadly understood parameters of the operation of lighting fixtures in mixed systems and the improvement of the quality of electricity, considered in two aspects: as receivers of the energy consumed, determining and generating reactive power, influencing the asymmetry of currents and the production of higher harmonics, determined by the parameters of current and supply voltage (independent of the consumers connected at the connection point), which are influenced by the consumers that are connected at the connection point. After the tests, in order to improve the quality of energy, a proprietary program for the design of passive resonance filters was developed. A wide range of measurements of various types of lighting devices was carried out in single, complex, and mixed systems. Luminaires with discharge and LED sources were selected for the analysis of energy parameters. The tests were carried out in accordance with the IEEE 1459-2010 standard for single-phase circuits with distorted waveforms. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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13 pages, 17174 KiB

Open AccessArticle

Efficiency of Laser-Shaped Photovoltaic Cells

by Ewa Korzeniewska, Mariusz Tomczyk, Łukasz Pietrzak, Miralem Hadžiselimović, Bojan Štumberger, Klemen Sredenšek and Sebastijan Seme

Energies 2020, 13(18), 4747; https://doi.org/10.3390/en13184747 - 11 Sep 2020

Cited by 11 | Viewed by 2956

Abstract

The main aim of this paper is to analyze the influence of laser shaping of the photovoltaic cell based on its efficiency. The authors described both process of the monocrystalline photovoltaic cell manufacturing, its efficiency, and the possibilities of usage in architecture and [...] Read more.

The main aim of this paper is to analyze the influence of laser shaping of the photovoltaic cell based on its efficiency. The authors described both process of the monocrystalline photovoltaic cell manufacturing, its efficiency, and the possibilities of usage in architecture and the process of creating the photovoltaic cells of unconventional shapes by using laser technology. A method for cutting photovoltaic cells using a fiber laser was presented as well as the parameters of the laser cutting process. The described method allows cutting the massively produced silicon cells according to the predetermined trajectory. Using the proposed process parameters, satisfactory cutting edge quality, and negligible impact of the laser beam on changes in the structure of the photovoltaic cell active layers were achieved. In each cycle of structure cutting, only a small part of the material is removed (from 1 to 2 μm), and depending on the thickness, the process is repeated from 50 to 300 times. It has been shown that the efficiency of the modified cells depends on the ratio of their surface area to the laser cutting line. Full article

(This article belongs to the Special Issue Electromagnetic Energy in Modern Engineering and Medical Technologies)

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