Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651635
D. Desideri, A. Maschio, E. Poli
A conductive sphere is proposed as simple model for the evaluation of the human exposure to electric fields under an overhead medium voltage power line. The study is performed on the sphere (on the top and on the horizontal equatorial circumference), with reference to an overhead line supported by reinforced concrete poles, with a pole-top-pin arrangement. A numerical analysis compares the results relative to this simple model with those of a more complete one of the human body. An experimental validation of the numerical analysis is reported. The human exposure under the line is finally discussed, in particular near to and far from a pole.
{"title":"Human exposure to electric fields under an overhead MV power line","authors":"D. Desideri, A. Maschio, E. Poli","doi":"10.1109/UPEC.2008.4651635","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651635","url":null,"abstract":"A conductive sphere is proposed as simple model for the evaluation of the human exposure to electric fields under an overhead medium voltage power line. The study is performed on the sphere (on the top and on the horizontal equatorial circumference), with reference to an overhead line supported by reinforced concrete poles, with a pole-top-pin arrangement. A numerical analysis compares the results relative to this simple model with those of a more complete one of the human body. An experimental validation of the numerical analysis is reported. The human exposure under the line is finally discussed, in particular near to and far from a pole.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133191618","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651597
M.R. Wadi, M. Bara, O. Carlson, F.A. Elammari
Voltage stability has been of increasing importance in facing the rising risks of voltage collapses or system blackouts, and in trying to improve systems power quality, particularly in the relatively small and fast growing interconnected power systems of developing regions. This paper describes and identifies the recorded voltage fluctuations leading to some voltage collapses in the South-West Libyan electric power system, as a first step of handling this problem.
{"title":"Voltage stability analysis and improvement for the South-West Libya electrical power system part 1: Problem identification","authors":"M.R. Wadi, M. Bara, O. Carlson, F.A. Elammari","doi":"10.1109/UPEC.2008.4651597","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651597","url":null,"abstract":"Voltage stability has been of increasing importance in facing the rising risks of voltage collapses or system blackouts, and in trying to improve systems power quality, particularly in the relatively small and fast growing interconnected power systems of developing regions. This paper describes and identifies the recorded voltage fluctuations leading to some voltage collapses in the South-West Libyan electric power system, as a first step of handling this problem.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"244 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134273846","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651660
Mostafa Sedighizadeh, M. Khatibi, M. T. Keshavarzi
Semiconductor rectifier transformers, which supply DC load currents, always deal with harmonic problems since the rectifier circuit connected to their secondary windings generates harmonic currents. These harmonic currents play a vital role in accurate designing of such transformers. As it is often impossible to model the transformer and the rectifier together during design process, design engineers do appropriate calculations based on sinusoidal normal operation of the transformer and finally add some correctional factors according to the excising standards to consider the harmonic conditions. This is practically time consuming and there is a high risk of various mistakes. It is the purpose of this paper to make a database including 11 types of rectifier circuits, frequently used for industrial purposes, and to develop a simulating software for design considerations on semiconductor rectifier transformers. In the developed software, the transformer and the chosen rectifier circuit are simulated simultaneously, their harmonic analysis is done, and next, the transformer parameters are designed based on the extracted harmonic spectrum and their effects on transformers. Finally, an example of IEEE Standard No.C57.18.10.1998 is calculated by means of the developed software as a case study. Comparing the results obtained here with those given in the standard, obviously proves the capabilities of this software.
{"title":"An algorithm for design considerations on semiconductor rectifier transformers","authors":"Mostafa Sedighizadeh, M. Khatibi, M. T. Keshavarzi","doi":"10.1109/UPEC.2008.4651660","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651660","url":null,"abstract":"Semiconductor rectifier transformers, which supply DC load currents, always deal with harmonic problems since the rectifier circuit connected to their secondary windings generates harmonic currents. These harmonic currents play a vital role in accurate designing of such transformers. As it is often impossible to model the transformer and the rectifier together during design process, design engineers do appropriate calculations based on sinusoidal normal operation of the transformer and finally add some correctional factors according to the excising standards to consider the harmonic conditions. This is practically time consuming and there is a high risk of various mistakes. It is the purpose of this paper to make a database including 11 types of rectifier circuits, frequently used for industrial purposes, and to develop a simulating software for design considerations on semiconductor rectifier transformers. In the developed software, the transformer and the chosen rectifier circuit are simulated simultaneously, their harmonic analysis is done, and next, the transformer parameters are designed based on the extracted harmonic spectrum and their effects on transformers. Finally, an example of IEEE Standard No.C57.18.10.1998 is calculated by means of the developed software as a case study. Comparing the results obtained here with those given in the standard, obviously proves the capabilities of this software.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134538659","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651579
H. Karimi-Davijani, A. Sheikholeslami, R. Ahmadi, H. Livani
This paper presents dynamic modeling and simulation of a doubly fed induction generator (DFIG) wind turbine based on space vector pulse width modulation (SVPWM) converter. SVPWM is applied to partial scale power electronic converters as grid side and rotor side converter. All power and control units are performed in PSCAD/EMTDC software. Dynamic response in grid connected mode for variable speed wind operation and abnormal condition as a short circuit fault are investigated. Simulation results prove, decouple control of active and reactive power of DFIG using SVPWM converter enhances system response and power quality of wind turbine.
{"title":"Active and reactive power control of DFIG using SVPWM converter","authors":"H. Karimi-Davijani, A. Sheikholeslami, R. Ahmadi, H. Livani","doi":"10.1109/UPEC.2008.4651579","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651579","url":null,"abstract":"This paper presents dynamic modeling and simulation of a doubly fed induction generator (DFIG) wind turbine based on space vector pulse width modulation (SVPWM) converter. SVPWM is applied to partial scale power electronic converters as grid side and rotor side converter. All power and control units are performed in PSCAD/EMTDC software. Dynamic response in grid connected mode for variable speed wind operation and abnormal condition as a short circuit fault are investigated. Simulation results prove, decouple control of active and reactive power of DFIG using SVPWM converter enhances system response and power quality of wind turbine.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134614670","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651548
F. Sheidaei, M. Shadkam, M. Zarei
This paper presents a method for optimal allocation of distributed generation in distribution systems. In this paper, our aim would be optimal distributed generation allocation for loss reduction in distribution network. Ant colony search algorithm (ACSA) was used as solving tool. ACSA is inspired from the natural behaviour of the ant colonies on how they find the food source and bring them back to their nest by building the unique trail formation. This algorithm is used to minimize an objective function. For applying ACSA, a soft ware is programmed under Matlab software is prepared. This proposed ACSA method and genetic algorithm (GA) are implemented on IEEE 34 bus system, and the results show that the proposed method is better than the other two methods. Using the proper and optimal allocation of DG has many advantages, but the lack of it has disadvantages, such as: increasing losses, voltage flicker, and harmonic.
{"title":"Optimal Distributed Generation allocation in distirbution systems employing ant colony to reduce losses","authors":"F. Sheidaei, M. Shadkam, M. Zarei","doi":"10.1109/UPEC.2008.4651548","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651548","url":null,"abstract":"This paper presents a method for optimal allocation of distributed generation in distribution systems. In this paper, our aim would be optimal distributed generation allocation for loss reduction in distribution network. Ant colony search algorithm (ACSA) was used as solving tool. ACSA is inspired from the natural behaviour of the ant colonies on how they find the food source and bring them back to their nest by building the unique trail formation. This algorithm is used to minimize an objective function. For applying ACSA, a soft ware is programmed under Matlab software is prepared. This proposed ACSA method and genetic algorithm (GA) are implemented on IEEE 34 bus system, and the results show that the proposed method is better than the other two methods. Using the proper and optimal allocation of DG has many advantages, but the lack of it has disadvantages, such as: increasing losses, voltage flicker, and harmonic.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116130781","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651518
M. Vahid, A. A. Hossein, M. Kazem
In this paper, a problem of optimal capacitor placement and conductor selection is solved for a nonuniform radial distribution system with lateral subfeeders. In this optimization problem the loads of the system is considered to be nonlinear. The voltage of each bus along the feeder after capacitor and conductor installation is calculated for each harmonic order. The total voltage and current harmonic distortions are calculated and added to the fundamental values. The new updated voltage and current values are used to solve for the capacitor and conductor optimal size and location as well as the net dollar savings. The algorithm is applied on a 27-bus radial distribution system with lateral subfeeders, and the results are given for different cases; before and after optimization.
{"title":"Maximum loss reduction applying combination of optimal conductor selection and capacitor placement in distribution systems with nonlinear loads","authors":"M. Vahid, A. A. Hossein, M. Kazem","doi":"10.1109/UPEC.2008.4651518","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651518","url":null,"abstract":"In this paper, a problem of optimal capacitor placement and conductor selection is solved for a nonuniform radial distribution system with lateral subfeeders. In this optimization problem the loads of the system is considered to be nonlinear. The voltage of each bus along the feeder after capacitor and conductor installation is calculated for each harmonic order. The total voltage and current harmonic distortions are calculated and added to the fundamental values. The new updated voltage and current values are used to solve for the capacitor and conductor optimal size and location as well as the net dollar savings. The algorithm is applied on a 27-bus radial distribution system with lateral subfeeders, and the results are given for different cases; before and after optimization.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115116511","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651581
L. McClean, L. Bryans, J. Colandairaj, B. Fox, B. O'sullivan
Governments in many countries including UK & Ireland are incentivising a higher percentage of electric power from renewable sources. In many places achieving this objective is heavily dependent on wind power. Historically, networks developed to serve load and are weak in windy areas. Network development requires permissions and therefore takes many years. This paper explores equipment and analysis to develop a set of line up-rating characteristics linked to the output of wind farms. The system and analysis is to provide an interim measure to enable power planners to connect more renewable energy sources while permission for new lines is being obtained. The equipment involves line mounted current and conductor surface temperature transducers and weather stations arranged regularly along the route. The information is transmitted by GPRS to a Web server where preliminary analysis presents information derived from the data. Further validation and analysis is carried out by downloading the raw data from the remote server. At the time of writing the paper the physical works are complete and validation/analysis is underway.
{"title":"Equipment and methodology for linking overhead line circuit ratings to the output of nearby windfarms","authors":"L. McClean, L. Bryans, J. Colandairaj, B. Fox, B. O'sullivan","doi":"10.1109/UPEC.2008.4651581","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651581","url":null,"abstract":"Governments in many countries including UK & Ireland are incentivising a higher percentage of electric power from renewable sources. In many places achieving this objective is heavily dependent on wind power. Historically, networks developed to serve load and are weak in windy areas. Network development requires permissions and therefore takes many years. This paper explores equipment and analysis to develop a set of line up-rating characteristics linked to the output of wind farms. The system and analysis is to provide an interim measure to enable power planners to connect more renewable energy sources while permission for new lines is being obtained. The equipment involves line mounted current and conductor surface temperature transducers and weather stations arranged regularly along the route. The information is transmitted by GPRS to a Web server where preliminary analysis presents information derived from the data. Further validation and analysis is carried out by downloading the raw data from the remote server. At the time of writing the paper the physical works are complete and validation/analysis is underway.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123491118","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651459
Youbing Zhang, Wei Chen, Xiao Zheng, Weng Guo-qing, Yijia Cao
With the impact of interruptible load (IL) to power system and the security of power grid, this paper points out that IL is one of the security providers. Then the model of power grid operation security cost is presented. The security cost consists of the generating reserve cost, the IL cost, the rescheduling cost and the expected system instability cost. A lingo program is used to optimize the model. The rationality and feasibility of the model here are demonstrated by IEEE30 bus power system.
{"title":"Study on model of power grid operation security cost in market environment","authors":"Youbing Zhang, Wei Chen, Xiao Zheng, Weng Guo-qing, Yijia Cao","doi":"10.1109/UPEC.2008.4651459","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651459","url":null,"abstract":"With the impact of interruptible load (IL) to power system and the security of power grid, this paper points out that IL is one of the security providers. Then the model of power grid operation security cost is presented. The security cost consists of the generating reserve cost, the IL cost, the rescheduling cost and the expected system instability cost. A lingo program is used to optimize the model. The rationality and feasibility of the model here are demonstrated by IEEE30 bus power system.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"205 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113959149","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651491
M. Aghamohammadi, A. Ghorbani, S. Pourmohammad
In this paper a Posicast controller is designed to improve the power system stability containing the transient and the small signal stability. Unlike most of the recently published excitation control schemes, Posicast control is an unsophisticated and easy to implement control method that can effectively improve the stability of the system without increasing the complexity of the control system. The proposed controller is simulated under several large and small sudden 3-phase faults occurred in the different parts of the lines. It is also shown that the proposed controller increases the capability of the system in damping the oscillations caused by changing the exciter reference signal. In other words only one controller is used to improve the transient and small signal stability as well as the voltage stability. The results from extensive time domain simulations using MATLAB/Simulink demonstrate that the offered control strategy is superior to the conventional excitation control methods and can improve performance of the system in the all testing conditions. A performance index is also used to validate the effectiveness of the proposed controller in improving the system stability.
{"title":"Enhancing transient and small signal stability in power systems using a posicast excitation controller","authors":"M. Aghamohammadi, A. Ghorbani, S. Pourmohammad","doi":"10.1109/UPEC.2008.4651491","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651491","url":null,"abstract":"In this paper a Posicast controller is designed to improve the power system stability containing the transient and the small signal stability. Unlike most of the recently published excitation control schemes, Posicast control is an unsophisticated and easy to implement control method that can effectively improve the stability of the system without increasing the complexity of the control system. The proposed controller is simulated under several large and small sudden 3-phase faults occurred in the different parts of the lines. It is also shown that the proposed controller increases the capability of the system in damping the oscillations caused by changing the exciter reference signal. In other words only one controller is used to improve the transient and small signal stability as well as the voltage stability. The results from extensive time domain simulations using MATLAB/Simulink demonstrate that the offered control strategy is superior to the conventional excitation control methods and can improve performance of the system in the all testing conditions. A performance index is also used to validate the effectiveness of the proposed controller in improving the system stability.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125362558","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651631
D. Desideri, M. Guarnieri, A. Maschio, F. Moro
A three-dimensional integral procedure based on the cell method and suitable for simulating non-magnetic shields has been proposed recently. Its validation against systematic measurements is here presented. A good agreement between computed and measured magnetic field RMS values confirms that the proposed integral procedure can be used confidently in designing shielding apparatuses for MV/LV substations.
{"title":"Magnetic shielding of MV/LV substations: Numerical modeling and experimental validation","authors":"D. Desideri, M. Guarnieri, A. Maschio, F. Moro","doi":"10.1109/UPEC.2008.4651631","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651631","url":null,"abstract":"A three-dimensional integral procedure based on the cell method and suitable for simulating non-magnetic shields has been proposed recently. Its validation against systematic measurements is here presented. A good agreement between computed and measured magnetic field RMS values confirms that the proposed integral procedure can be used confidently in designing shielding apparatuses for MV/LV substations.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126443009","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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