Pub Date : 2017-05-01DOI: 10.1109/EPE.2017.7967331
Carlos Daniel de Sousa Bezerra, W. Calixto, M. R. da Cunha Reis, C. Bezerra, A. Alves
The objective of this work is to develop a model that represents the thermoelectric generation plant with the purpose of optimizing the search of the maximum power point in the thermoelectric generators. Are used converters DC-DC controlled by artificial intelligence techniques. The method consists of regulating the voltage to connect various loads as batteries, and compare the optimal control methods with the classic control methods. The results show that the neural network makes it possible to carry out the process of learning the power pattern to estimate the work cycle quickly and efficiently. The Fuzzy controller totally eliminates overshoot and gets fast response time with satisfactory performance.
{"title":"Optimization of the operation power of DC-DC converters applied to thermogenerators","authors":"Carlos Daniel de Sousa Bezerra, W. Calixto, M. R. da Cunha Reis, C. Bezerra, A. Alves","doi":"10.1109/EPE.2017.7967331","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967331","url":null,"abstract":"The objective of this work is to develop a model that represents the thermoelectric generation plant with the purpose of optimizing the search of the maximum power point in the thermoelectric generators. Are used converters DC-DC controlled by artificial intelligence techniques. The method consists of regulating the voltage to connect various loads as batteries, and compare the optimal control methods with the classic control methods. The results show that the neural network makes it possible to carry out the process of learning the power pattern to estimate the work cycle quickly and efficiently. The Fuzzy controller totally eliminates overshoot and gets fast response time with satisfactory performance.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115866640","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967288
M. Florkowski, M. Kuniewski, J. Furgał, P. Pająk
Nowadays voltage transients in electrical power systems can take different shapes related to properties of distortion source and physical phenomenon appearing in systems. Usually overvoltages contain oscillation components of different frequencies, which are propagating along lines reaching transformer terminals. Overvoltages impact power transformer insulation systems in spite of used overvoltage protection. Analysis of overvoltages in winding insulation systems have strong importance in proper and reliable work of transformers. Due to complex configuration of transformer winding different overvoltages levels can occur inside winding than at winding terminals. This article presents investigation of internal overvoltages in distribution transformer windings. Analysis was based on measurements results of transient voltages and frequency characteristics. Investigation of resonance frequencies based on winding admittance measurements was made also.
{"title":"Investigation of overvoltages in distribution transformers","authors":"M. Florkowski, M. Kuniewski, J. Furgał, P. Pająk","doi":"10.1109/EPE.2017.7967288","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967288","url":null,"abstract":"Nowadays voltage transients in electrical power systems can take different shapes related to properties of distortion source and physical phenomenon appearing in systems. Usually overvoltages contain oscillation components of different frequencies, which are propagating along lines reaching transformer terminals. Overvoltages impact power transformer insulation systems in spite of used overvoltage protection. Analysis of overvoltages in winding insulation systems have strong importance in proper and reliable work of transformers. Due to complex configuration of transformer winding different overvoltages levels can occur inside winding than at winding terminals. This article presents investigation of internal overvoltages in distribution transformer windings. Analysis was based on measurements results of transient voltages and frequency characteristics. Investigation of resonance frequencies based on winding admittance measurements was made also.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132103267","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967257
J. Šenk, I. Laznickova, I. Jakubová
The paper deals with the power loss distribution along the arc heater with intensively blasted electric arc and compares the measured power loss of individual parts of the arc heater and power loss computed using a simple model of the electric arc. In previous works, the authors have presented the simple model of electric arc burning in the arc heater channel. Measured integral quantities obtained during numerous experiments served as input data of the model and attention has been focused at finding the development of the arc radius and temperature along the arc heater's channel that meets the experimentally obtained integral values as a whole. In this contribution, the arc heater is divided into several parts whose power loss is measured and computed separately. For this purpose, the arc model has been adopted to make it possible. The aim is to obtain more detailed information on processes taking place in individual parts of the arc heater. The results reveal that for the input and main part of the arc heater's anode channel the computed and measured power loss differ mutually in opposite sense. This observation raises new questions concerning the suitability of presumptions, approximations and/or simplifications used in the modelling. Further experiments and computations are needed. The conclusions can be useful for the design of similar devices, and for more precise modelling of the behavior of electric arc inside the arc heater channel.
{"title":"Power loss distribution along the arc heater with intensively blasted electric arc","authors":"J. Šenk, I. Laznickova, I. Jakubová","doi":"10.1109/EPE.2017.7967257","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967257","url":null,"abstract":"The paper deals with the power loss distribution along the arc heater with intensively blasted electric arc and compares the measured power loss of individual parts of the arc heater and power loss computed using a simple model of the electric arc. In previous works, the authors have presented the simple model of electric arc burning in the arc heater channel. Measured integral quantities obtained during numerous experiments served as input data of the model and attention has been focused at finding the development of the arc radius and temperature along the arc heater's channel that meets the experimentally obtained integral values as a whole. In this contribution, the arc heater is divided into several parts whose power loss is measured and computed separately. For this purpose, the arc model has been adopted to make it possible. The aim is to obtain more detailed information on processes taking place in individual parts of the arc heater. The results reveal that for the input and main part of the arc heater's anode channel the computed and measured power loss differ mutually in opposite sense. This observation raises new questions concerning the suitability of presumptions, approximations and/or simplifications used in the modelling. Further experiments and computations are needed. The conclusions can be useful for the design of similar devices, and for more precise modelling of the behavior of electric arc inside the arc heater channel.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130814938","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967286
P. Karlovsky, J. Lettl
Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.
{"title":"Improvement of DTC performance using luenberger observer for flux estimation","authors":"P. Karlovsky, J. Lettl","doi":"10.1109/EPE.2017.7967286","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967286","url":null,"abstract":"Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124067155","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967260
J. Laksar, J. Sobra, L. Veg
The subject of this paper is the calculation of the induction machine air gap flux density distribution. Following previous paper, the parameters affecting the distribution are integrated to create the final no-load flux density distribution. The no-load calculations are valid for every type of winding and can be applied to almost every type of electric machine. To calculate the flux density distribution in loaded condition, the magnitude and phase shift of the rotor current have to be calculated. The rotor magnetomotive force reaction distribution is calculated according to the stator calculations. Based on the equivalent circuit of the machine, the flux density distribution of variable load condition can be calculated. All numerical results are compared with the finite element analysis calculations and the distribution and spectral analysis of the air gap flux density are evaluated in this paper.
{"title":"Numerical calculation of the effect of the induction machine load on the air gap magnetic flux density distribution","authors":"J. Laksar, J. Sobra, L. Veg","doi":"10.1109/EPE.2017.7967260","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967260","url":null,"abstract":"The subject of this paper is the calculation of the induction machine air gap flux density distribution. Following previous paper, the parameters affecting the distribution are integrated to create the final no-load flux density distribution. The no-load calculations are valid for every type of winding and can be applied to almost every type of electric machine. To calculate the flux density distribution in loaded condition, the magnitude and phase shift of the rotor current have to be calculated. The rotor magnetomotive force reaction distribution is calculated according to the stator calculations. Based on the equivalent circuit of the machine, the flux density distribution of variable load condition can be calculated. All numerical results are compared with the finite element analysis calculations and the distribution and spectral analysis of the air gap flux density are evaluated in this paper.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124376740","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967314
P. Totzauer, P. Trnka, J. Hornak, P. Kadlec, J. Pihera
The insulating liquids for power transformers are still evolving area. The current trend is to move away from currently used mineral oil because it poses a threat to the environment and use the renewable, biodegradable nature ester oils instead. These oils are now well known but what keeps them from widespread usage are unbalanced properties. In some areas these natural oils excel (fire point, sulfur content, etc.) but in others they still need improvement (dissipation factor, oxidative stability). This paper deals primarily with dielectric properties of the nature ester oil (rapeseed oil) with a focus on improvement of an oxidation stability. The emphasis is placed on a conservation of good dielectric properties for a long time thanks to the addition of an antioxidant. The experiment is based on preparation and measurement of the rapeseed oil with the different amount of several antioxidants. Evaluation of the impact of antioxidants on the dielectric properties of oils in the supplied state is performed via measurement of a breakdown voltage and a dissipation factor. The effect of antioxidant addition on the properties of oil, which is exposed to elevated temperature, is determined via a test of oxidation stability. The evaluation of this test is based on the comparison of values of the dissipation factor at the beginning and at the end of the test. The additional method for assessing of changes in the chemical structure (associated with oxidation processes) is Fourier transform infrared spectroscopy.
{"title":"Antioxidant variations in the nature ester oil","authors":"P. Totzauer, P. Trnka, J. Hornak, P. Kadlec, J. Pihera","doi":"10.1109/EPE.2017.7967314","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967314","url":null,"abstract":"The insulating liquids for power transformers are still evolving area. The current trend is to move away from currently used mineral oil because it poses a threat to the environment and use the renewable, biodegradable nature ester oils instead. These oils are now well known but what keeps them from widespread usage are unbalanced properties. In some areas these natural oils excel (fire point, sulfur content, etc.) but in others they still need improvement (dissipation factor, oxidative stability). This paper deals primarily with dielectric properties of the nature ester oil (rapeseed oil) with a focus on improvement of an oxidation stability. The emphasis is placed on a conservation of good dielectric properties for a long time thanks to the addition of an antioxidant. The experiment is based on preparation and measurement of the rapeseed oil with the different amount of several antioxidants. Evaluation of the impact of antioxidants on the dielectric properties of oils in the supplied state is performed via measurement of a breakdown voltage and a dissipation factor. The effect of antioxidant addition on the properties of oil, which is exposed to elevated temperature, is determined via a test of oxidation stability. The evaluation of this test is based on the comparison of values of the dissipation factor at the beginning and at the end of the test. The additional method for assessing of changes in the chemical structure (associated with oxidation processes) is Fourier transform infrared spectroscopy.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121798977","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967344
Oliver Marcincin, Zdenek Medvec, P. Moldrik
This article discusses rechargeable stations for electric vehicles. Deals with the current infrastructure, assumed progress of electro mobility, estimated amount of electric energy required for charging of electric vehicles. There are analyzed topics such as methods of charging of batteries in electric vehicles, basic concept of charging station. Also is included practical measurement on a small charging station in the region of Ostrava.
{"title":"The impact of electric vehicles on distribution network","authors":"Oliver Marcincin, Zdenek Medvec, P. Moldrik","doi":"10.1109/EPE.2017.7967344","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967344","url":null,"abstract":"This article discusses rechargeable stations for electric vehicles. Deals with the current infrastructure, assumed progress of electro mobility, estimated amount of electric energy required for charging of electric vehicles. There are analyzed topics such as methods of charging of batteries in electric vehicles, basic concept of charging station. Also is included practical measurement on a small charging station in the region of Ostrava.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123604045","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967258
Robert Bafa, P. Lesáková, J. Heckenbergerova
With the growing concern about sustainable development and sustainable energy, there exists increasing pressure on energy-efficiency technologies to reduce energy use and greenhouse gas emissions. This paper discusses and analyzes on real regional data the potential of biomass in energy-efficiency issues, how to determine the volume of changes of heating from coal or natural gas to wood and the effects of biomass combustion expansion. However, also the role of grants provided by governments to support energy-efficiency initiatives is explained.
{"title":"Setting of target values for household heating by wood","authors":"Robert Bafa, P. Lesáková, J. Heckenbergerova","doi":"10.1109/EPE.2017.7967258","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967258","url":null,"abstract":"With the growing concern about sustainable development and sustainable energy, there exists increasing pressure on energy-efficiency technologies to reduce energy use and greenhouse gas emissions. This paper discusses and analyzes on real regional data the potential of biomass in energy-efficiency issues, how to determine the volume of changes of heating from coal or natural gas to wood and the effects of biomass combustion expansion. However, also the role of grants provided by governments to support energy-efficiency initiatives is explained.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125401437","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967274
Ladislav Rudolf, V. Král, Antonin Samaj
This paper deals with the methodology of software to promote optimised operation of the transmission network. The methodology is based on the real data referring to operating temperatures and the power transmitted over 220 kV and 400 kV lines. This is an input database, formed by the values of power transmitted at a real time temperature. The software designed here offers a choice of the line to be observed with the option to set the temperature range. The outcome produced will comprise a graphic depiction of operation of the selected transmitter network line with respect to the power transmitted. The graphic depiction of operating course helps show the technical losses associated with the value referring to power transmitted. The methodology of this function has been simulated using an MS Excel sheet.
{"title":"Software solution for optimisation of transmission network operation","authors":"Ladislav Rudolf, V. Král, Antonin Samaj","doi":"10.1109/EPE.2017.7967274","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967274","url":null,"abstract":"This paper deals with the methodology of software to promote optimised operation of the transmission network. The methodology is based on the real data referring to operating temperatures and the power transmitted over 220 kV and 400 kV lines. This is an input database, formed by the values of power transmitted at a real time temperature. The software designed here offers a choice of the line to be observed with the option to set the temperature range. The outcome produced will comprise a graphic depiction of operation of the selected transmitter network line with respect to the power transmitted. The graphic depiction of operating course helps show the technical losses associated with the value referring to power transmitted. The methodology of this function has been simulated using an MS Excel sheet.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128571668","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 : 2017-05-01DOI: 10.1109/EPE.2017.7967240
L. Marciniak, M. Piątek
The paper presents a method for detecting non-linear high resistance earth faults in compensated medium voltage networks, based on the criterion of reactive power of higher harmonics of zero sequence current and voltage. Harmonics content of currents and voltages as the function of network parameters and nonlinear fault resistance was estimated. The model of earth fault protection using that criterion was described. Detection examples of low and very high-resistance earth-faults were attached.
{"title":"Detection of high resistance earth faults in medium voltage networks using higher harmonics","authors":"L. Marciniak, M. Piątek","doi":"10.1109/EPE.2017.7967240","DOIUrl":"https://doi.org/10.1109/EPE.2017.7967240","url":null,"abstract":"The paper presents a method for detecting non-linear high resistance earth faults in compensated medium voltage networks, based on the criterion of reactive power of higher harmonics of zero sequence current and voltage. Harmonics content of currents and voltages as the function of network parameters and nonlinear fault resistance was estimated. The model of earth fault protection using that criterion was described. Detection examples of low and very high-resistance earth-faults were attached.","PeriodicalId":201464,"journal":{"name":"2017 18th International Scientific Conference on Electric Power Engineering (EPE)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124559638","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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