Numerical calculation of short connection current is a very important part of control, regulation and protection of the power supply system. Each important element of our system must be included in this calculation. An efficient algorithm for numerical calculation of elements of a power transformer equivalent circuit is described in this work. The finite element method was used for numerical calculation of nonlinear magnetic field. The energy method and method of mutual fluxes were used for calculation of the magnetic leakage flux. It is well known that the energy method, because of its simplicity and efficiency, is very often used for solving problems of this type. The mutual flux method has rarely been used because of its complexity and long duration of calculations. This work shows that the mutual flux method can be useful and successful for these calculations, by means of high-speed computers. The method for experimental determination of leakage flux was shown in this work, by means of the modern digital electronic measurement devices, as well. The results of this experiment were used to check the precision of numerical methods that have been used.
{"title":"Numerical calculation of power transformers equivalent circuit parameters","authors":"J. Smajic, V. Madžarević, S. Bernerovic","doi":"10.1109/PTC.1999.826527","DOIUrl":"https://doi.org/10.1109/PTC.1999.826527","url":null,"abstract":"Numerical calculation of short connection current is a very important part of control, regulation and protection of the power supply system. Each important element of our system must be included in this calculation. An efficient algorithm for numerical calculation of elements of a power transformer equivalent circuit is described in this work. The finite element method was used for numerical calculation of nonlinear magnetic field. The energy method and method of mutual fluxes were used for calculation of the magnetic leakage flux. It is well known that the energy method, because of its simplicity and efficiency, is very often used for solving problems of this type. The mutual flux method has rarely been used because of its complexity and long duration of calculations. This work shows that the mutual flux method can be useful and successful for these calculations, by means of high-speed computers. The method for experimental determination of leakage flux was shown in this work, by means of the modern digital electronic measurement devices, as well. The results of this experiment were used to check the precision of numerical methods that have been used.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129638947","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}
An often-used method for intensification of the high power arc furnaces is to increase the length of the arc. In this case it is usually necessary to change the furnace transformer and the electrode controller. Of course, due to the higher power, the conditions of the connection to the supply network are also investigated. The paper gives the analyses of the experiences gained at such an intensification process primarily focusing on the low frequency EMC problems. Measurement results are shown to illustrate the observed phenomena.
{"title":"Some problems of the active power enhancement of the high power arc furnaces","authors":"A. Kárpáti, I. Karacs, T. Magyar","doi":"10.1109/PTC.1999.826604","DOIUrl":"https://doi.org/10.1109/PTC.1999.826604","url":null,"abstract":"An often-used method for intensification of the high power arc furnaces is to increase the length of the arc. In this case it is usually necessary to change the furnace transformer and the electrode controller. Of course, due to the higher power, the conditions of the connection to the supply network are also investigated. The paper gives the analyses of the experiences gained at such an intensification process primarily focusing on the low frequency EMC problems. Measurement results are shown to illustrate the observed phenomena.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129131597","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}
This paper presents the bifurcation properties of both single-phase and three-phase induction motors. Several induction motor characteristics are presented as well as their interaction with mechanical load characteristics and network characteristics. Finally, a case of cascaded motor stalling in a simple power system with two induction motors is presented.
{"title":"Bifurcation analysis of induction motors","authors":"C. Vournas, G. Manos, M. Karystianos","doi":"10.1109/PTC.1999.826541","DOIUrl":"https://doi.org/10.1109/PTC.1999.826541","url":null,"abstract":"This paper presents the bifurcation properties of both single-phase and three-phase induction motors. Several induction motor characteristics are presented as well as their interaction with mechanical load characteristics and network characteristics. Finally, a case of cascaded motor stalling in a simple power system with two induction motors is presented.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124003483","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}
This paper presents the implementation of a new method in calculating the optimal unit commitment and economic dispatch of industrial enterprises with its own energy supply system, mostly with CHP-plants. To yield the most synergetic effects, both the marketplace and the demand of disposable industrial processes are taken into account. Because of the complexity of the formulated mathematical model and, thus, of the optimization problem, a new dynamic search strategy (DSS) based on mixed integer linear programming (MILP) is presented. With DSS, a considerable acceleration of calculation time could be achieved.
{"title":"Optimal operation of industrial CHP-based power systems in liberalized energy markets","authors":"S. Illerhaus, J. Verstege","doi":"10.1109/PTC.1999.826642","DOIUrl":"https://doi.org/10.1109/PTC.1999.826642","url":null,"abstract":"This paper presents the implementation of a new method in calculating the optimal unit commitment and economic dispatch of industrial enterprises with its own energy supply system, mostly with CHP-plants. To yield the most synergetic effects, both the marketplace and the demand of disposable industrial processes are taken into account. Because of the complexity of the formulated mathematical model and, thus, of the optimization problem, a new dynamic search strategy (DSS) based on mixed integer linear programming (MILP) is presented. With DSS, a considerable acceleration of calculation time could be achieved.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121675845","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}
This paper presents a linear programming (LP) based direct reactive optimal power flow (OFF) to optimally allocate reactive power in a given instantaneous state of a system. The main focus of the paper is on accuracy and convergence rate of the developed OFF. The issue of performance characteristics arises from the inability of the LP based OPF to converge spontaneously. A bound reduction heuristics technique is developed to enforce the convergence of the OPF. Extensive case studies are carried out on the IEEE-118 bus system to illustrate the impact of different bound reduction parameters on the convergence rate and the accuracy of the solution.
{"title":"Performance characteristics of an OPF for allocation of VArs in a competitive environment","authors":"S. Ahmed, G. Strbac","doi":"10.1109/PTC.1999.826475","DOIUrl":"https://doi.org/10.1109/PTC.1999.826475","url":null,"abstract":"This paper presents a linear programming (LP) based direct reactive optimal power flow (OFF) to optimally allocate reactive power in a given instantaneous state of a system. The main focus of the paper is on accuracy and convergence rate of the developed OFF. The issue of performance characteristics arises from the inability of the LP based OPF to converge spontaneously. A bound reduction heuristics technique is developed to enforce the convergence of the OPF. Extensive case studies are carried out on the IEEE-118 bus system to illustrate the impact of different bound reduction parameters on the convergence rate and the accuracy of the solution.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124303969","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}
This paper approaches the optimization of radial primary distribution networks as a composite problem by examining combined alternative technical solutions, relating to conductor replacements or reinforcements, capacitor installation and voltage regulator placement. The overall optimization problem is examined on a long-term basis taking into account the realistic network configuration and load data (locations, variation, growth) and specific technical constraints (voltage drop, conductor thermal and economic capacity, conductor tapering, fault current conductor capability). The aim is to satisfy the growing demand for electricity in such a way that it is both technically acceptable and reasonably economical (minimization of losses). For this reason the technically acceptable solutions are economically estimated and the more economical one is adopted.
{"title":"Combined long-term optimization of radial primary distribution networks","authors":"A. Safigianni, G. Salis","doi":"10.1109/PTC.1999.826497","DOIUrl":"https://doi.org/10.1109/PTC.1999.826497","url":null,"abstract":"This paper approaches the optimization of radial primary distribution networks as a composite problem by examining combined alternative technical solutions, relating to conductor replacements or reinforcements, capacitor installation and voltage regulator placement. The overall optimization problem is examined on a long-term basis taking into account the realistic network configuration and load data (locations, variation, growth) and specific technical constraints (voltage drop, conductor thermal and economic capacity, conductor tapering, fault current conductor capability). The aim is to satisfy the growing demand for electricity in such a way that it is both technically acceptable and reasonably economical (minimization of losses). For this reason the technically acceptable solutions are economically estimated and the more economical one is adopted.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124084953","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}
In order to base power system protective measures against lightning overvoltages on a regional data collection, the authors intend to develop a modern computer-based lightning detecting and photonic locating system. In this paper, the operating principles of the lightning detection and some experimental results of thunderstorm activity in Thailand are discussed.
{"title":"Computer based lightning detection and photonic location","authors":"F. Serghei, S. Sangkasaad","doi":"10.1109/PTC.1999.826576","DOIUrl":"https://doi.org/10.1109/PTC.1999.826576","url":null,"abstract":"In order to base power system protective measures against lightning overvoltages on a regional data collection, the authors intend to develop a modern computer-based lightning detecting and photonic locating system. In this paper, the operating principles of the lightning detection and some experimental results of thunderstorm activity in Thailand are discussed.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134409465","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}
Summary form only given. This paper makes an in-depth analysis of shaft torsional phenomena in steam turbine-generator-exciter shafts of generators in Poland and Sweden which may result from ripple current superimposed on the HVDC link current in an HVDC asynchronous link. The analysis relates to the 600 MW, 450 kV HVDC cable which is to connect Vattenfall's Karshamn oil-fired power station in the South of Sweden to Dunovo in the North of Poland where the length of the submarine cable is approximately 237 km. The studies are performed for machines in close proximity to the converter station in both Sweden and Poland. It extends earlier work to analyze attenuation (or amplification) of DC ripple current at the inverter due to the submarine cable with its overhead line in Poland and the line's associated smoothing inductors. It examines HVDC link harmonic scaling factors and AC system scaling factors for modulation product harmonic currents impressed on the generators of the Swedish and Polish grid networks by the inverter, not examined in-depth in the literature heretofore.
{"title":"Sweden/Poland power link: impact of variable frequency rectifier ripple currents on torsional stressing of turbine-generator shafts","authors":"T. Hammons","doi":"10.1109/PTC.1999.826706","DOIUrl":"https://doi.org/10.1109/PTC.1999.826706","url":null,"abstract":"Summary form only given. This paper makes an in-depth analysis of shaft torsional phenomena in steam turbine-generator-exciter shafts of generators in Poland and Sweden which may result from ripple current superimposed on the HVDC link current in an HVDC asynchronous link. The analysis relates to the 600 MW, 450 kV HVDC cable which is to connect Vattenfall's Karshamn oil-fired power station in the South of Sweden to Dunovo in the North of Poland where the length of the submarine cable is approximately 237 km. The studies are performed for machines in close proximity to the converter station in both Sweden and Poland. It extends earlier work to analyze attenuation (or amplification) of DC ripple current at the inverter due to the submarine cable with its overhead line in Poland and the line's associated smoothing inductors. It examines HVDC link harmonic scaling factors and AC system scaling factors for modulation product harmonic currents impressed on the generators of the Swedish and Polish grid networks by the inverter, not examined in-depth in the literature heretofore.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131780085","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}
J. Coulondre, R. Le-Port, N. Maruejouls, A. Videau, A. Bondarenko, V. Guerikh
The TESIS-UPS interconnection Project aimed at assessing the requirements and the feasibility of synchronous interconnection between the Trans European Synchronously Interconnected System (TESIS) system and the Unified Power System (UPS). It is financed by the European Community (TACIS fund). As a first stage of this study, the combination of an economical analysis together with a network study allow to assess clearly the level of exchanges together with the network consistency to be considered.
{"title":"Profitable power exchanges and available transmission capacity between two large systems: the example of the European TESIS-UPS Interconnection","authors":"J. Coulondre, R. Le-Port, N. Maruejouls, A. Videau, A. Bondarenko, V. Guerikh","doi":"10.1109/PTC.1999.826436","DOIUrl":"https://doi.org/10.1109/PTC.1999.826436","url":null,"abstract":"The TESIS-UPS interconnection Project aimed at assessing the requirements and the feasibility of synchronous interconnection between the Trans European Synchronously Interconnected System (TESIS) system and the Unified Power System (UPS). It is financed by the European Community (TACIS fund). As a first stage of this study, the combination of an economical analysis together with a network study allow to assess clearly the level of exchanges together with the network consistency to be considered.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131088543","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}
D. Alves, L. D. da Silva, C. Castro, V.F. da Costa
The conventional Newton and fast decoupled load flow methods are considered to be inadequate to obtain the system's maximum loading point due to ill-conditioning problems at and near this critical point. At this point the Jacobian matrix of the Newton-Raphson method becomes singular, and the P-V and Q-/spl theta/ decoupling assumptions made for the fast decoupled load flow formulation no longer hold. However, results obtained for the IEEE systems (14, 30, 57 and 118 buses) have shown that appropriate modifications in the above methods make them adequate for the computation of the complete bifurcation diagrams. Besides, the characteristics of the conventional methods are preserved.
{"title":"Modified Newton and fast decoupled load flows for tracing power systems bifurcation diagrams","authors":"D. Alves, L. D. da Silva, C. Castro, V.F. da Costa","doi":"10.1109/PTC.1999.826714","DOIUrl":"https://doi.org/10.1109/PTC.1999.826714","url":null,"abstract":"The conventional Newton and fast decoupled load flow methods are considered to be inadequate to obtain the system's maximum loading point due to ill-conditioning problems at and near this critical point. At this point the Jacobian matrix of the Newton-Raphson method becomes singular, and the P-V and Q-/spl theta/ decoupling assumptions made for the fast decoupled load flow formulation no longer hold. However, results obtained for the IEEE systems (14, 30, 57 and 118 buses) have shown that appropriate modifications in the above methods make them adequate for the computation of the complete bifurcation diagrams. Besides, the characteristics of the conventional methods are preserved.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133690871","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：