Pub Date : 2007-07-01DOI: 10.1109/PCT.2007.4538318
E. Spahić, G. Balzer
The impact of the wind power on the power system stability and control is already notable. With the increase of their power (single offshore wind farms will reach over 1000 MW) their impact will increase too. In this paper the use of voltage source converter HVDC transmission technology for the connection of the large offshore wind farms to the power system will be presented. The modelling of VSC HVDC and its control parameters and loops has been detailed. The impact of such connection on the power system stability and control has been analysed on a test power system.
{"title":"Impact of the VSC HVDC Connection of Large Offshore Wind Farms on Power System Stability and Control","authors":"E. Spahić, G. Balzer","doi":"10.1109/PCT.2007.4538318","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538318","url":null,"abstract":"The impact of the wind power on the power system stability and control is already notable. With the increase of their power (single offshore wind farms will reach over 1000 MW) their impact will increase too. In this paper the use of voltage source converter HVDC transmission technology for the connection of the large offshore wind farms to the power system will be presented. The modelling of VSC HVDC and its control parameters and loops has been detailed. The impact of such connection on the power system stability and control has been analysed on a test power system.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130871295","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538641
F. Rivas-Dávalos, E. Moreno-Goytia, G. Gutierrez-Alacaraz, J. Tovar-Hernández
Electric utility industry is currently facing a market deregulated environment and many technological advances. In this context, the demand for electric power having higher network security, better power quality, improved system reliability, and availability is increasing every day. This complex scenario put the electric utilities under conflicting pressure between meeting the growth demands, reducing its operation cost, keeping maintenance and construction and try to provide lower rates for customers or to improve the company profits. Therefore, solutions for planning, design and operation of power systems involve the simultaneous optimization of multiple objectives, often conflicting between them. This work presents the state of the art of multi-objective evolutionary algorithms applications to electrical power systems, in order to provide the power system engineering community with the expertise about the development of multi-objective optimization paradigms and trends in the applications of multi-objective evolutionary algorithms, altogether useful for tackling down every-day electrical networks challenges.
{"title":"Evolutionary Multi-Objective Optimization in Power Systems: State-of-the-Art","authors":"F. Rivas-Dávalos, E. Moreno-Goytia, G. Gutierrez-Alacaraz, J. Tovar-Hernández","doi":"10.1109/PCT.2007.4538641","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538641","url":null,"abstract":"Electric utility industry is currently facing a market deregulated environment and many technological advances. In this context, the demand for electric power having higher network security, better power quality, improved system reliability, and availability is increasing every day. This complex scenario put the electric utilities under conflicting pressure between meeting the growth demands, reducing its operation cost, keeping maintenance and construction and try to provide lower rates for customers or to improve the company profits. Therefore, solutions for planning, design and operation of power systems involve the simultaneous optimization of multiple objectives, often conflicting between them. This work presents the state of the art of multi-objective evolutionary algorithms applications to electrical power systems, in order to provide the power system engineering community with the expertise about the development of multi-objective optimization paradigms and trends in the applications of multi-objective evolutionary algorithms, altogether useful for tackling down every-day electrical networks challenges.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131176881","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538593
S. Almeida, N. Machado, R. Pestana
The objective of this paper is to describe a process which was developed in the Portuguese TSO (REN - Rede Electrica Nacional, SA) whose main purpose is to identify voltage collapse situations without the need for the specific EMS module. The process is based on the power flow module of PSS/E software from Siemens Power Transmission Distribution, Inc., running automatically through an application developed in Python, which performs a SV analysis. Its results are available via browser from control room PC's and are updated every 30 minutes, allowing to monitor the system security levels and to take suitable remedial actions to prevent a voltage collapse situation. The need to develop a process to identify voltage collapse situations in the Portuguese Transmission System arose with voltage problems identified in a specific substation when performing N-l contingency analysis. The operator training simulator, an important tool to analyse and understand the power system behaviour, was also used to study and demonstrate the voltage collapse phenomenon.
{"title":"Voltage Collapse: Real Time and Preventive Analysis in the Portuguese Transmission System","authors":"S. Almeida, N. Machado, R. Pestana","doi":"10.1109/PCT.2007.4538593","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538593","url":null,"abstract":"The objective of this paper is to describe a process which was developed in the Portuguese TSO (REN - Rede Electrica Nacional, SA) whose main purpose is to identify voltage collapse situations without the need for the specific EMS module. The process is based on the power flow module of PSS/E software from Siemens Power Transmission Distribution, Inc., running automatically through an application developed in Python, which performs a SV analysis. Its results are available via browser from control room PC's and are updated every 30 minutes, allowing to monitor the system security levels and to take suitable remedial actions to prevent a voltage collapse situation. The need to develop a process to identify voltage collapse situations in the Portuguese Transmission System arose with voltage problems identified in a specific substation when performing N-l contingency analysis. The operator training simulator, an important tool to analyse and understand the power system behaviour, was also used to study and demonstrate the voltage collapse phenomenon.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131121043","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538475
R. P. Thomas, C. Solver
A method has been developed for synchronizing the trip commands to a HV circuit breaker in order to achieve a preselected optimum arcing time, even under transient asymmetrical fault current conditions. The algorithm estimates parameters of the fault current by applying least means squares regression to a generic model and sampled values of the current in each phase. An analysis of variance is made between the sampled and modeled currents to provide additional control and as a basis for discrimination between grounded and ungrounded fault cases. In addition, high power experiments have been conducted to investigate the stability of minimum arcing times of HV SF6 circuit breakers over a large succession of interruptions. The data from these experiments indicates good stability in the minimum arcing time behavior, thus providing important information for the viability of synchronizing circuit breakers in order to avoid unnecessarily long arcing times.
{"title":"A Method for Controlled Fault Interruption for Use with HV SF6 Circuit Breakers","authors":"R. P. Thomas, C. Solver","doi":"10.1109/PCT.2007.4538475","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538475","url":null,"abstract":"A method has been developed for synchronizing the trip commands to a HV circuit breaker in order to achieve a preselected optimum arcing time, even under transient asymmetrical fault current conditions. The algorithm estimates parameters of the fault current by applying least means squares regression to a generic model and sampled values of the current in each phase. An analysis of variance is made between the sampled and modeled currents to provide additional control and as a basis for discrimination between grounded and ungrounded fault cases. In addition, high power experiments have been conducted to investigate the stability of minimum arcing times of HV SF6 circuit breakers over a large succession of interruptions. The data from these experiments indicates good stability in the minimum arcing time behavior, thus providing important information for the viability of synchronizing circuit breakers in order to avoid unnecessarily long arcing times.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132874437","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538605
I. Nordanlycke, G. Bossert, H. Glavitsch
In a treatment of security and congestion management large interconnections consisting of networks operated by independent organizations are considered. The security of the proper network surrounded by several neighbors is in the focus. The analytical steps for measuring, estimation, boundary matching and load flow calculation including an appropriate tool are described. Special features for the estimation, matching of neighboring networks and modeling of components are given. The highlights of the performance and the precision of the results are underlined, supplemented by the way in which results in a user oriented manner are presented. The tool is implemented in a control center of a member of the UCTE network.
{"title":"Security and Congestion Management Tool for the Use in Extended Transmission Systems","authors":"I. Nordanlycke, G. Bossert, H. Glavitsch","doi":"10.1109/PCT.2007.4538605","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538605","url":null,"abstract":"In a treatment of security and congestion management large interconnections consisting of networks operated by independent organizations are considered. The security of the proper network surrounded by several neighbors is in the focus. The analytical steps for measuring, estimation, boundary matching and load flow calculation including an appropriate tool are described. Special features for the estimation, matching of neighboring networks and modeling of components are given. The highlights of the performance and the precision of the results are underlined, supplemented by the way in which results in a user oriented manner are presented. The tool is implemented in a control center of a member of the UCTE network.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"172 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132163716","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538283
E. Handschin, I. Jurgens, J. Weller, M. Zdrallek
The condition based maintenance (CBM) of high-voltage power supply systems provides many economic benefits compared to other maintenance strategies, if relevant data for the assessment of the assets condition are available. In order to collect them systematically, uniform checklists have been developed for different types of assets. They are used as input data for an expert system and a mathematical method, which allow the estimation of the assets condition by calculating normalized parameters. Although the basic approaches of the developed methods are quite different, their application on power transformers and circuit breakers lead to very similar results, so that both methods validate each other to a large extent. Part of the mathematical model is the consideration of uncertainty according to imprecise and missing datasets, so that a margin of deviation regarding the condition parameters can be determined.
{"title":"Novel Methods for the Condition Based Maintenance of Distribution Networks","authors":"E. Handschin, I. Jurgens, J. Weller, M. Zdrallek","doi":"10.1109/PCT.2007.4538283","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538283","url":null,"abstract":"The condition based maintenance (CBM) of high-voltage power supply systems provides many economic benefits compared to other maintenance strategies, if relevant data for the assessment of the assets condition are available. In order to collect them systematically, uniform checklists have been developed for different types of assets. They are used as input data for an expert system and a mathematical method, which allow the estimation of the assets condition by calculating normalized parameters. Although the basic approaches of the developed methods are quite different, their application on power transformers and circuit breakers lead to very similar results, so that both methods validate each other to a large extent. Part of the mathematical model is the consideration of uncertainty according to imprecise and missing datasets, so that a margin of deviation regarding the condition parameters can be determined.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"447 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132451269","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538560
P. Mack, F. Capitanescu, M. Glavic, F. Legrand, L. Wehenkel
In this paper we present objectives and strategies of the NAVELEC research project co-funded by the European GNSS Supervisory Authority with funding from the 6th Framework Programme of the European Community for Research and Technological Development. The project objective is to assess how the European Global Navigation Satellite System related solutions can enhance the operation and control of the European power system over wide areas. Some basic functionalities of the GALILEO system are given first, then we summarize the questionnaire, set at the initial stage of the project, and provide the analysis of received responses from transmission system operators. Two generic strategies to upgrade existing electrical power transmission networks as well as major steps to upgrade underlying infrastructures, are presented.
{"title":"Application of the Galileo System for a Better Synchronization of Electrical Power Systems","authors":"P. Mack, F. Capitanescu, M. Glavic, F. Legrand, L. Wehenkel","doi":"10.1109/PCT.2007.4538560","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538560","url":null,"abstract":"In this paper we present objectives and strategies of the NAVELEC research project co-funded by the European GNSS Supervisory Authority with funding from the 6th Framework Programme of the European Community for Research and Technological Development. The project objective is to assess how the European Global Navigation Satellite System related solutions can enhance the operation and control of the European power system over wide areas. Some basic functionalities of the GALILEO system are given first, then we summarize the questionnaire, set at the initial stage of the project, and provide the analysis of received responses from transmission system operators. Two generic strategies to upgrade existing electrical power transmission networks as well as major steps to upgrade underlying infrastructures, are presented.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124520975","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538474
A. Guldbrand, O. Samuelsson
Centralized Petersen coil earthing in networks with extensive use of underground cable involves flow of large quantities of reactive earth fault current. In networks with long radial cable feeders this creates problems involving active losses and active and reactive earth fault current. One possible solution to the problem is the use of local compensation. This paper aims at understanding the limitations of traditionally compensated networks and compares these to networks that are locally compensated. This is done through analytical calculations and PSCAD simulations that are combined with results from a project studying cables in Swedish distribution networks. In addition, basic PSCAD simulations are used to clarify how the rating and placing of the distributed compensation units affects active earth fault current and investment costs.
{"title":"Central or Local Compensation of Earth-Fault Currents in Non-Effectively Earthed Distribution Systems","authors":"A. Guldbrand, O. Samuelsson","doi":"10.1109/PCT.2007.4538474","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538474","url":null,"abstract":"Centralized Petersen coil earthing in networks with extensive use of underground cable involves flow of large quantities of reactive earth fault current. In networks with long radial cable feeders this creates problems involving active losses and active and reactive earth fault current. One possible solution to the problem is the use of local compensation. This paper aims at understanding the limitations of traditionally compensated networks and compares these to networks that are locally compensated. This is done through analytical calculations and PSCAD simulations that are combined with results from a project studying cables in Swedish distribution networks. In addition, basic PSCAD simulations are used to clarify how the rating and placing of the distributed compensation units affects active earth fault current and investment costs.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114711265","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538479
K. Tuitemwong, S. Premrudeepreechacharn
The number of the small power producers (SPP) has been increased. It makes the scale of the distribution system more complicated and difficult to design the protective devices coordination due to its effected to distribution system. Hence, This paper presents an expert system for protective devices coordination in radial distribution network with considered small power producers. The scope of this study is the radial distribution system 22 kV or 33 kV with the protective devices such as over current relay, recloser and fuse. The proposed expert system has been implemented and simulated. The simulation results have shown that it generates satisfactory results. In addition, it takes a few minute to calculate the results.
{"title":"Expert System for Protective Devices Coordination in Radial Distribution Network with Small Power Producers","authors":"K. Tuitemwong, S. Premrudeepreechacharn","doi":"10.1109/PCT.2007.4538479","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538479","url":null,"abstract":"The number of the small power producers (SPP) has been increased. It makes the scale of the distribution system more complicated and difficult to design the protective devices coordination due to its effected to distribution system. Hence, This paper presents an expert system for protective devices coordination in radial distribution network with considered small power producers. The scope of this study is the radial distribution system 22 kV or 33 kV with the protective devices such as over current relay, recloser and fuse. The proposed expert system has been implemented and simulated. The simulation results have shown that it generates satisfactory results. In addition, it takes a few minute to calculate the results.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117031785","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 : 2007-07-01DOI: 10.1109/PCT.2007.4538589
A.G. Chaoyun, B.L. Ran
At present, electric load forecasting method and model are all point forecasting to the load, the paper proposes a method of short-term load forecasting using the cloud model which represents the artificial intelligence with uncertainty. The forecasting results are many discrete data sets which are uncertain and change in some range, so they can represent the changing characteristic of electric load more actually. In the paper, the author firstly introduces the conception and characteristic of cloud model and gives the process of data discretization and conception zooming for the load data and the weather factors based on cloud model. Then the paper carries on the mining and inference of uncertainty rules using the associated knowledge algorithm based on cloud model (Cloud-Association- Rules), and finally uses the data of some area as the forecasting analysis example, gives two kinds of results expression which are the forecasting sets distribution chart and the excepted values graphic chart. The forecasting results can meet the practical standard of electric load forecasting.
目前，电力负荷预测方法和模型都是对负荷进行点预测，本文提出了一种利用具有不确定性的人工智能代表的云模型进行短期负荷预测的方法。预测结果是许多不确定且在一定范围内变化的离散数据集，因此更能真实地反映电力负荷的变化特征。本文首先介绍了云模型的概念和特点，给出了基于云模型对负荷数据和天气因素进行数据离散化和概念放大的过程。然后利用基于云模型的关联知识算法(cloud - association - rules)对不确定性规则进行挖掘和推理，最后以某地区的数据为预测分析实例，给出预测集分布图和例外值图两种结果表达。预测结果能够满足电力负荷预测的实际要求。
{"title":"Study on Short Term Load Forecast based on Cloud Model","authors":"A.G. Chaoyun, B.L. Ran","doi":"10.1109/PCT.2007.4538589","DOIUrl":"https://doi.org/10.1109/PCT.2007.4538589","url":null,"abstract":"At present, electric load forecasting method and model are all point forecasting to the load, the paper proposes a method of short-term load forecasting using the cloud model which represents the artificial intelligence with uncertainty. The forecasting results are many discrete data sets which are uncertain and change in some range, so they can represent the changing characteristic of electric load more actually. In the paper, the author firstly introduces the conception and characteristic of cloud model and gives the process of data discretization and conception zooming for the load data and the weather factors based on cloud model. Then the paper carries on the mining and inference of uncertainty rules using the associated knowledge algorithm based on cloud model (Cloud-Association- Rules), and finally uses the data of some area as the forecasting analysis example, gives two kinds of results expression which are the forecasting sets distribution chart and the excepted values graphic chart. The forecasting results can meet the practical standard of electric load forecasting.","PeriodicalId":356805,"journal":{"name":"2007 IEEE Lausanne Power Tech","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116422511","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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