Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021186
Georgi Ivanov, V. Mateev, I. Marinova
This paper presents some transient and static characteristics of hybrid high temperature superconducting (HTS) flat coil prototypes. Two HTS coil prototypes were designed using 3D CAD software for working in hybrid HTS system consisting of superconducting part (in cold condition) and nonsuperconducting part (in warm condition). The coils consist of HTS flat composite wires with superconducting layer of GdBCO. Inductance of the created coils was calculated using existing analytical formulas and measured experimentally in warm and cold (superconducting) state. Theoretically, calculated inductance was compared with measured values. Critical temperature and resistance were measured during the transition from superconducting to nonsuperconducting state. A design for coreless superconducting transformer was proposed and tested. This design is suitable for superconducting wireless power transfer with very high efficiency.
{"title":"Static and Transient Characteristics of Hybrid HTS Coils","authors":"Georgi Ivanov, V. Mateev, I. Marinova","doi":"10.1109/BulEF56479.2022.10021186","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021186","url":null,"abstract":"This paper presents some transient and static characteristics of hybrid high temperature superconducting (HTS) flat coil prototypes. Two HTS coil prototypes were designed using 3D CAD software for working in hybrid HTS system consisting of superconducting part (in cold condition) and nonsuperconducting part (in warm condition). The coils consist of HTS flat composite wires with superconducting layer of GdBCO. Inductance of the created coils was calculated using existing analytical formulas and measured experimentally in warm and cold (superconducting) state. Theoretically, calculated inductance was compared with measured values. Critical temperature and resistance were measured during the transition from superconducting to nonsuperconducting state. A design for coreless superconducting transformer was proposed and tested. This design is suitable for superconducting wireless power transfer with very high efficiency.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122354071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10020204
Slav Dimitrov, Dimitar Totev, Stiliyan Nikolov, R. Dimitrova
The purpose of this paper is design of automatic compost production system powered by green energy sources. Special control algorithm and program code are developed for implementation in the system. SCADA system is used for supervisory control and diagnostics which allows automation and optimization of the process
{"title":"Design of Compost Production System Powered by Green Energy Sources","authors":"Slav Dimitrov, Dimitar Totev, Stiliyan Nikolov, R. Dimitrova","doi":"10.1109/BulEF56479.2022.10020204","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10020204","url":null,"abstract":"The purpose of this paper is design of automatic compost production system powered by green energy sources. Special control algorithm and program code are developed for implementation in the system. SCADA system is used for supervisory control and diagnostics which allows automation and optimization of the process","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128819076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021202
G. Cherneva, S. Filipova-Petrakieva
In harmony with modern energy policy and the need to use alternative energy sources, the development of photovoltaic (PV) systems increases. At the same time, the requirements for their energy efficiency and optimal operation also increases and being specified. For this reason, an in-depth study of their individual components and operating modes are required at the PV system design stage. This requires the development of adequate mathematical and simulation models to perform a detailed preliminary analysis of the behavior of PV systems. The object of consideration in this work is an autonomous photovoltaic system designed and developed by the Scientific Research Practice working group at the “T. Kableshkov” University of Transport titled “Study of applications, using voltage converters in renewable energy systems with hydroelectric power”. It contains a photovoltaic module, a buck (step-down) DC-DC converter, a Maximum Power Point Tracking (MPPT) controller, and a DC load. In this paper, a simulation model of the analyzed photovoltaic system is presented. It has been developed in a Matlab/Simulink environment where simulations have been performed under different atmospheric conditions. The simulation results are compared with experimentally collected data and system characteristics and the corresponding results are analyzed. On this basis, the adequacy and accuracy of the proposed model are evaluated in comparison with the real working photovoltaic system.
{"title":"Modeling and Analysis of an Autonomous Photovoltaic System for Laboratory Research","authors":"G. Cherneva, S. Filipova-Petrakieva","doi":"10.1109/BulEF56479.2022.10021202","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021202","url":null,"abstract":"In harmony with modern energy policy and the need to use alternative energy sources, the development of photovoltaic (PV) systems increases. At the same time, the requirements for their energy efficiency and optimal operation also increases and being specified. For this reason, an in-depth study of their individual components and operating modes are required at the PV system design stage. This requires the development of adequate mathematical and simulation models to perform a detailed preliminary analysis of the behavior of PV systems. The object of consideration in this work is an autonomous photovoltaic system designed and developed by the Scientific Research Practice working group at the “T. Kableshkov” University of Transport titled “Study of applications, using voltage converters in renewable energy systems with hydroelectric power”. It contains a photovoltaic module, a buck (step-down) DC-DC converter, a Maximum Power Point Tracking (MPPT) controller, and a DC load. In this paper, a simulation model of the analyzed photovoltaic system is presented. It has been developed in a Matlab/Simulink environment where simulations have been performed under different atmospheric conditions. The simulation results are compared with experimentally collected data and system characteristics and the corresponding results are analyzed. On this basis, the adequacy and accuracy of the proposed model are evaluated in comparison with the real working photovoltaic system.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128233012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021154
Margreta P. Vasileva, Iva Draganova-Zlateva, Neli Zafiroska
Different types of dielectrics are used in the manufacture of insulation systems of electrical equipment. Each individual facility may have a different type of insulation defect. On the basis of a developed simulation model, the report presents a variant study of partial discharge in different dielectric media, at different sizes of the applied voltage and different sizes of air inclusion.
{"title":"Results of simulation modeling of an insulation system with the development of a partial discharge in the volume of a solid dielectric","authors":"Margreta P. Vasileva, Iva Draganova-Zlateva, Neli Zafiroska","doi":"10.1109/BulEF56479.2022.10021154","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021154","url":null,"abstract":"Different types of dielectrics are used in the manufacture of insulation systems of electrical equipment. Each individual facility may have a different type of insulation defect. On the basis of a developed simulation model, the report presents a variant study of partial discharge in different dielectric media, at different sizes of the applied voltage and different sizes of air inclusion.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114222493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021179
Martin Ralchev, V. Mateev, I. Marinova
This work presents 3D printing of passive electronic elements for printed circuit board integration, using the Fused Filament Fabrication (FFF) technology. 3D printing is an innovative method that can be applied to produce volumetric printed circuit boards and ease the manufacturing, deploying, assembly and connecting processes. This paper shows the standard steps in the printed circuit board manufacturing process and how it can be facilitated by 3D printing technology. Capabilities of existing 3D printing polymer FFF materials as electrically conductive, insolative and magnetically permeable are explored. 3D printing technology features in the process of manufacturing printed circuit board passive elements are presented. Electric impedance parameters of printed models of electric wire traces, inductors and bulk capacitor are measured in the frequency band up to 100kHz.
{"title":"High Frequency Impedance of 3D Printed Electric Circuit Models","authors":"Martin Ralchev, V. Mateev, I. Marinova","doi":"10.1109/BulEF56479.2022.10021179","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021179","url":null,"abstract":"This work presents 3D printing of passive electronic elements for printed circuit board integration, using the Fused Filament Fabrication (FFF) technology. 3D printing is an innovative method that can be applied to produce volumetric printed circuit boards and ease the manufacturing, deploying, assembly and connecting processes. This paper shows the standard steps in the printed circuit board manufacturing process and how it can be facilitated by 3D printing technology. Capabilities of existing 3D printing polymer FFF materials as electrically conductive, insolative and magnetically permeable are explored. 3D printing technology features in the process of manufacturing printed circuit board passive elements are presented. Electric impedance parameters of printed models of electric wire traces, inductors and bulk capacitor are measured in the frequency band up to 100kHz.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126107491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021208
K. Georgiev, K. Nikolova, Dobrinka Krasteva
The main purpose of sports lighting is to create the necessary horizontal and vertical illumination of the playing field. Control over the design of sports lighting systems is an important ancillary part of the whole process. It is necessary because it controls the quality of the design and the subsequent level of maintenance of the lighting installation. Amortization of existing lighting systems enables new modern engineering solutions to optimize the operation of the system, i.e. to be economical. This means that the necessary lighting is achieved with a minimum consumption of energy and materials, with the most suitable selection of lighting fixtures and lighting system.
{"title":"Design and control of sports lighting projects","authors":"K. Georgiev, K. Nikolova, Dobrinka Krasteva","doi":"10.1109/BulEF56479.2022.10021208","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021208","url":null,"abstract":"The main purpose of sports lighting is to create the necessary horizontal and vertical illumination of the playing field. Control over the design of sports lighting systems is an important ancillary part of the whole process. It is necessary because it controls the quality of the design and the subsequent level of maintenance of the lighting installation. Amortization of existing lighting systems enables new modern engineering solutions to optimize the operation of the system, i.e. to be economical. This means that the necessary lighting is achieved with a minimum consumption of energy and materials, with the most suitable selection of lighting fixtures and lighting system.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131166165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021149
S. Filipova-Petrakieva
The static characteristics of loads in linear electric circuits are linear. This means that the resistances, inductances, and capacitances are constants and they do not depend on the operating mode. The transients of these circuits are always steady-states, i.e. they always tend to a certain stationary mode since the values of the currents and voltages there cannot increase indefinitely. Depending on the values of resistors, coils, and capacitors in a linear electric circuit three types of transients occur under DC sources, namely: overdamped, critically damped, and underdamped. A danger for the analyzed DC circuit is the underdamped transients. For this reason, it is necessary to determine these values of the parameters of the passive elements that lead to the threshold critically damped transients in linear electric circuit. In this paper, the sufficient condition for the occurrence of overdamped, critically damped, and underdamped transients in linear electric circuits is used. A parametric analysis of the type of transients on illustrative examples of second-order circuits (with the two conservative elements) is made. The three types of transients, varying parameters of the passive elements (resistors, coils, and capacitors), are analyzed. The present paper is an educational tool to improve students' knowledge in the field of transient responses appearing in linear circuits under constant energy sources.
{"title":"Parametric Analysis of Transients in Linear Electric Circuits under DC Power Supply","authors":"S. Filipova-Petrakieva","doi":"10.1109/BulEF56479.2022.10021149","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021149","url":null,"abstract":"The static characteristics of loads in linear electric circuits are linear. This means that the resistances, inductances, and capacitances are constants and they do not depend on the operating mode. The transients of these circuits are always steady-states, i.e. they always tend to a certain stationary mode since the values of the currents and voltages there cannot increase indefinitely. Depending on the values of resistors, coils, and capacitors in a linear electric circuit three types of transients occur under DC sources, namely: overdamped, critically damped, and underdamped. A danger for the analyzed DC circuit is the underdamped transients. For this reason, it is necessary to determine these values of the parameters of the passive elements that lead to the threshold critically damped transients in linear electric circuit. In this paper, the sufficient condition for the occurrence of overdamped, critically damped, and underdamped transients in linear electric circuits is used. A parametric analysis of the type of transients on illustrative examples of second-order circuits (with the two conservative elements) is made. The three types of transients, varying parameters of the passive elements (resistors, coils, and capacitors), are analyzed. The present paper is an educational tool to improve students' knowledge in the field of transient responses appearing in linear circuits under constant energy sources.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133857874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021171
D. Nikolova, Dimo Stoilov
The European Union has been unsuccessful in its pursuit of energy independence. The Russo-Ukrainian conflict has introduced a new urgency to this problem. The paper explores the promise of moderate nuclear energy prolongation at the member state level as a supplement to the solution to both the decarbonization and energy-dependence dilemmas, brought in stark relief by recent developments in Ukraine.
{"title":"Russia, Ukraine and the European Union's Energy Future","authors":"D. Nikolova, Dimo Stoilov","doi":"10.1109/BulEF56479.2022.10021171","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021171","url":null,"abstract":"The European Union has been unsuccessful in its pursuit of energy independence. The Russo-Ukrainian conflict has introduced a new urgency to this problem. The paper explores the promise of moderate nuclear energy prolongation at the member state level as a supplement to the solution to both the decarbonization and energy-dependence dilemmas, brought in stark relief by recent developments in Ukraine.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133962746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The report presents a high-tech design solution based on the principle of sustainable development for the construction of the two hydrotechnical complexes: one at Nikopol-Turnu Magurele (at km. 580+650), and the other at Silistra-Klarash (at km. 384+500) through an innovative a technology fully in line with the protection of the environment and the preservation of the riverbanks and the fauna in the rivers in which hydroelectric power plants are built. The report proposes the use of a mo Bulb-turbine, which will help improve the ecological balance in the river basin and restore fish migration.
{"title":"Hydro Energy Use Of The Water Potential Of The Danube River","authors":"Iva Draganova-Zlateva, Valentin Kolev, Plamen Dilkov","doi":"10.1109/BulEF56479.2022.10021207","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021207","url":null,"abstract":"The report presents a high-tech design solution based on the principle of sustainable development for the construction of the two hydrotechnical complexes: one at Nikopol-Turnu Magurele (at km. 580+650), and the other at Silistra-Klarash (at km. 384+500) through an innovative a technology fully in line with the protection of the environment and the preservation of the riverbanks and the fauna in the rivers in which hydroelectric power plants are built. The report proposes the use of a mo Bulb-turbine, which will help improve the ecological balance in the river basin and restore fish migration.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116220508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021212
B. Boychev
The main tasks set before the opportunities for increasing energy efficiency and, in particular, increasing the use of electric power from renewable sources are primarily related to lowering greenhouse gas emissions, reducing power import costs, ensuring sustainable energy supplies, as well as increasing the reliability of the supply of electricity within the European Union (EU) compared to the supply of electricity produced from non-renewable energy sources. For this main purpose, energy efficiency has a priority role for the Energy Union and the EU supports the “energy efficiency first” rule.
{"title":"Energy efficiency and renewable energy sources","authors":"B. Boychev","doi":"10.1109/BulEF56479.2022.10021212","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021212","url":null,"abstract":"The main tasks set before the opportunities for increasing energy efficiency and, in particular, increasing the use of electric power from renewable sources are primarily related to lowering greenhouse gas emissions, reducing power import costs, ensuring sustainable energy supplies, as well as increasing the reliability of the supply of electricity within the European Union (EU) compared to the supply of electricity produced from non-renewable energy sources. For this main purpose, energy efficiency has a priority role for the Energy Union and the EU supports the “energy efficiency first” rule.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"332 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116534963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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