Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021176
Velichko Atanasov, Dimo Stoilov, Emil Mechkov
This article examines the issue of the increase in electrical energy losses in the iron cores of power transformers as a result of prolonged operation. A summary analysis of the results of measuring the losses of 200 pcs. power oil transformers after prolonged operation is provided. The results clearly show an increase in losses compared to the passport data provided by the manufacturing plant. The reasons for the increase were analyzed and compared for two different types of magnetic cores produced before and after 2000. The increase in idle running losses over five-year periods r% e determined using the Least squares method. Based on the statistical data from the measurements, a model is proposed for calculation of idle running losses using a linear dependence and an exponential function. The conducted research shows a good accuracy of the proposed approximation.
{"title":"Changes of iron losses during the service of distribution transformers","authors":"Velichko Atanasov, Dimo Stoilov, Emil Mechkov","doi":"10.1109/BulEF56479.2022.10021176","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021176","url":null,"abstract":"This article examines the issue of the increase in electrical energy losses in the iron cores of power transformers as a result of prolonged operation. A summary analysis of the results of measuring the losses of 200 pcs. power oil transformers after prolonged operation is provided. The results clearly show an increase in losses compared to the passport data provided by the manufacturing plant. The reasons for the increase were analyzed and compared for two different types of magnetic cores produced before and after 2000. The increase in idle running losses over five-year periods r% e determined using the Least squares method. Based on the statistical data from the measurements, a model is proposed for calculation of idle running losses using a linear dependence and an exponential function. The conducted research shows a good accuracy of the proposed approximation.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"2 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":"115696129","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/BulEF56479.2022.10021158
K. Savov, Dimo Stoilov, Kristina Hadzhiyska
The article presents a comprehensive description of an energy planning optimization model. It incorporates the electrical power grid represented at two voltage levels, part of the gas network, and focuses on the energy consumption side. The model uses linear optimization and is coded in GAMS. It is going to be extended with inclusion of other energy delivery and consumption technologies, detailed capacity considerations, and interactions with other economic sectors.
{"title":"Model for energy flow optimization and planning","authors":"K. Savov, Dimo Stoilov, Kristina Hadzhiyska","doi":"10.1109/BulEF56479.2022.10021158","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021158","url":null,"abstract":"The article presents a comprehensive description of an energy planning optimization model. It incorporates the electrical power grid represented at two voltage levels, part of the gas network, and focuses on the energy consumption side. The model uses linear optimization and is coded in GAMS. It is going to be extended with inclusion of other energy delivery and consumption technologies, detailed capacity considerations, and interactions with other economic sectors.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"95 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":"127537590","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/BulEF56479.2022.10021182
P. Rizov, R. Spasov, V. Petrov
This paper describes an application of Finite Element Method (FEM) to study the dependance of electromagnetic power on the load angle of synchronous generators while taking into account magnetic circuit saturation.
本文介绍了在考虑磁路饱和的情况下，应用有限元法研究同步发电机负载角对电磁功率的依赖关系。
{"title":"Study of the dependence of the electromagnetic power on the load angle with account of the saturation of the magnetic circuit in synchronous generators","authors":"P. Rizov, R. Spasov, V. Petrov","doi":"10.1109/BulEF56479.2022.10021182","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021182","url":null,"abstract":"This paper describes an application of Finite Element Method (FEM) to study the dependance of electromagnetic power on the load angle of synchronous generators while taking into account magnetic circuit saturation.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"65 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":"116084195","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/BulEF56479.2022.10021170
Yavor Lozanov, S. Tzvetkova, Angel Petleshkov
The paper presents mathematical models for determining the optimal moments of time for performing diagnostic tests of electrical equipment. Results, connecting the statistical characteristics for the reliability of electrical equipment and strategies for technical diagnostics of production systems are shown.
{"title":"Optimal programs for technical diagnostics","authors":"Yavor Lozanov, S. Tzvetkova, Angel Petleshkov","doi":"10.1109/BulEF56479.2022.10021170","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021170","url":null,"abstract":"The paper presents mathematical models for determining the optimal moments of time for performing diagnostic tests of electrical equipment. Results, connecting the statistical characteristics for the reliability of electrical equipment and strategies for technical diagnostics of production systems are shown.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"85 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":"129503141","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/BulEF56479.2022.10021165
Kiril Dimitrov
This paper examines the possibilities of participation of the Unified power flow controller in the damping of low-frequency fluctuations in power systems. A brief review was made regarding the structure of the device. A practical method for the implementation of classic PSS in the UPFC circuits is described, and several simulations have been made, both for the Single-machine infinity bus system, as well as for the four-machine system of Kundur.
{"title":"Possibilities for damping of low-frequency oscillations with Unified Power Flow Controller","authors":"Kiril Dimitrov","doi":"10.1109/BulEF56479.2022.10021165","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021165","url":null,"abstract":"This paper examines the possibilities of participation of the Unified power flow controller in the damping of low-frequency fluctuations in power systems. A brief review was made regarding the structure of the device. A practical method for the implementation of classic PSS in the UPFC circuits is described, and several simulations have been made, both for the Single-machine infinity bus system, as well as for the four-machine system of Kundur.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"20 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":"128792667","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/BulEF56479.2022.10020197
Gergana Vacheva, Plamen Stanchev, N. Hinov
In this research an economical assessment of the photovoltaic system for optimization of the number of the photovoltaic inverter is presented. This study can be useful for determination of the time for rehabilitation of the inverter in the solar system.
{"title":"Optimization of Inverter for PV Systems","authors":"Gergana Vacheva, Plamen Stanchev, N. Hinov","doi":"10.1109/BulEF56479.2022.10020197","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10020197","url":null,"abstract":"In this research an economical assessment of the photovoltaic system for optimization of the number of the photovoltaic inverter is presented. This study can be useful for determination of the time for rehabilitation of the inverter in the solar system.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"109 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":"128977142","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/BulEF56479.2022.10020203
K. Milanov, D. Gospodinova, M. Mintchev
The aim of the current study is to demonstrate that an AC/DC converter may operate in DC/DC converter mode while maintaining its functional and technical characteristics. The paper employs an experimental method, presenting a circuit schematic from which the main operating characteristics were obtained and demonstrated. The value of the coefficient of energy efficiency was evaluated in the presence of quickly fluctuating supply voltage values in the range from 400 to 600 V DC. The assigned task is simplified to evaluating the efficiency and functional characteristics of the supplied DC voltage convertor within the specified operating range. The developed AC/DC converter is intended for use in specific applications, such as batteries charging that provide converters power supply in EL-2 industrial locomotives, operating in the coal mining company Mini Maritsa Iztok EAD, Bulgaria. EL2 is a robust and straightforward machine with the Bo‘Bo’ axle arrangement, designed to haul heavy drafts at a moderate speed. These locomotives were built for voltages 1.2 or 2.4 kV DC.
当前研究的目的是证明AC/DC转换器可以在DC/DC转换器模式下工作，同时保持其功能和技术特性。本文采用实验方法，给出了电路原理图，从中得到了主要工作特性并进行了验证。能源效率系数的值是在400至600 V直流范围内电源电压值快速波动的情况下进行评估的。分配的任务被简化为在规定的工作范围内评估供电直流电压变换器的效率和功能特性。开发的AC/DC转换器旨在用于特定应用，例如在保加利亚Mini Maritsa Iztok EAD煤矿公司运营的EL-2工业机车中提供转换器电源的电池充电。EL2是一个强大的和直接的机器与Bo ' Bo '轴安排，旨在以中等速度拖重草稿。这些机车是为1.2或2.4千伏直流电压而制造的。
{"title":"Study of an AC/DC Convertor Powered by DC Voltage","authors":"K. Milanov, D. Gospodinova, M. Mintchev","doi":"10.1109/BulEF56479.2022.10020203","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10020203","url":null,"abstract":"The aim of the current study is to demonstrate that an AC/DC converter may operate in DC/DC converter mode while maintaining its functional and technical characteristics. The paper employs an experimental method, presenting a circuit schematic from which the main operating characteristics were obtained and demonstrated. The value of the coefficient of energy efficiency was evaluated in the presence of quickly fluctuating supply voltage values in the range from 400 to 600 V DC. The assigned task is simplified to evaluating the efficiency and functional characteristics of the supplied DC voltage convertor within the specified operating range. The developed AC/DC converter is intended for use in specific applications, such as batteries charging that provide converters power supply in EL-2 industrial locomotives, operating in the coal mining company Mini Maritsa Iztok EAD, Bulgaria. EL2 is a robust and straightforward machine with the Bo‘Bo’ axle arrangement, designed to haul heavy drafts at a moderate speed. These locomotives were built for voltages 1.2 or 2.4 kV DC.","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":"129457362","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/BulEF56479.2022.10021187
Ivan Tenchev, Daniel Dobrilov, Valeri Uzunov
The aim of the present development is the creation of a system for the utilisation of excess electrical energy from green energy sources. High-tech equipment is used in the system and a specialized algorithm has been developed for the operation of the modernised system. The system will be equipped with a specialised visualisation environment to monitor processes and process technologies. The visualisation environment will be SCADA-based and will have the ability to archive data and events. Thanks to this process, losses at limiting excess electrical energy generated from energy sources that are built only for their own needs in production enterprises will be optimised.
{"title":"System for utilisation of excess electrical energy generated from a renewable power source","authors":"Ivan Tenchev, Daniel Dobrilov, Valeri Uzunov","doi":"10.1109/BulEF56479.2022.10021187","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021187","url":null,"abstract":"The aim of the present development is the creation of a system for the utilisation of excess electrical energy from green energy sources. High-tech equipment is used in the system and a specialized algorithm has been developed for the operation of the modernised system. The system will be equipped with a specialised visualisation environment to monitor processes and process technologies. The visualisation environment will be SCADA-based and will have the ability to archive data and events. Thanks to this process, losses at limiting excess electrical energy generated from energy sources that are built only for their own needs in production enterprises will be optimised.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"3 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":"126879782","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/BulEF56479.2022.10021150
V. Mladenov, V. Chobanov, T. V. Van, Pencho Zlatev
The architecture, characteristics, and elements of Blockchain technology used to create a peer-to-peer energy trading platform are outlined in the paper. Here, we discussed the benefits of Blockchain and distributed ledger technology (DLT) for energy trading applications and how they assist the expanding decentralization and democratization ideologies in the energy industry.
{"title":"Blockchain-based trading process","authors":"V. Mladenov, V. Chobanov, T. V. Van, Pencho Zlatev","doi":"10.1109/BulEF56479.2022.10021150","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021150","url":null,"abstract":"The architecture, characteristics, and elements of Blockchain technology used to create a peer-to-peer energy trading platform are outlined in the paper. Here, we discussed the benefits of Blockchain and distributed ledger technology (DLT) for energy trading applications and how they assist the expanding decentralization and democratization ideologies in the energy industry.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"24 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":"133699934","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/BulEF56479.2022.10021209
M. Ivanova, Rositsa F. Dimitrova, Y. Kamenov
The continuous development of electric power systems in terms of implementation of new technologies for management and connection of new sources of energy makes the problem related to improving the security of power supply relevant. One of the common reasons causing power outages in the power grids is the human error of the maintenance and operating personnel. The present work is dedicated to the investigation and analysis of real emergency events with injured people caused by human errors in the operation of electrical equipment in power grids and substations. Based on the analysis, measures are proposed to prevent similar human errors.
{"title":"Analysis of emergency events as a result of human errors during the operation of electrical equipment in power grids","authors":"M. Ivanova, Rositsa F. Dimitrova, Y. Kamenov","doi":"10.1109/BulEF56479.2022.10021209","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021209","url":null,"abstract":"The continuous development of electric power systems in terms of implementation of new technologies for management and connection of new sources of energy makes the problem related to improving the security of power supply relevant. One of the common reasons causing power outages in the power grids is the human error of the maintenance and operating personnel. The present work is dedicated to the investigation and analysis of real emergency events with injured people caused by human errors in the operation of electrical equipment in power grids and substations. Based on the analysis, measures are proposed to prevent similar human errors.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"745 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":"127648998","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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