Summary form only given. Existing distribution networks have been designed with the assumption that the power flows from the substation to the load. The recent increase in the number of dispersed generation sources connected to MV lines invalidates this hypothesis, and this fact has consequences on the security and the quality of supply. This paper deals with the analysis method developed by Electricite de France to asses the impact of a prospected dispersed generator on steady state voltage quality, short circuit current and operation of the protection scheme. If a problem is detected, a range of feasible solutions is proposed. Given the number of generators connected each year to EDF Distribution Networks, the research and development division of EDP has developed computer software to automate these analysis.
{"title":"Assessing the impact of dispersed generation on medium voltage networks: analysis methods","authors":"D. Cortinas, P. Juston","doi":"10.1109/PTC.1999.826434","DOIUrl":"https://doi.org/10.1109/PTC.1999.826434","url":null,"abstract":"Summary form only given. Existing distribution networks have been designed with the assumption that the power flows from the substation to the load. The recent increase in the number of dispersed generation sources connected to MV lines invalidates this hypothesis, and this fact has consequences on the security and the quality of supply. This paper deals with the analysis method developed by Electricite de France to asses the impact of a prospected dispersed generator on steady state voltage quality, short circuit current and operation of the protection scheme. If a problem is detected, a range of feasible solutions is proposed. Given the number of generators connected each year to EDF Distribution Networks, the research and development division of EDP has developed computer software to automate these analysis.","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":"130104942","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 the context of deregulation of the electricity market, a special effort must be made to guarantee a high level of system reliability and supply quality. EDF has developed a tool called TOPASE for characterizing faults in electric power supply, particularly in terms of frequency and duration of power cuts at substations. It is designed around a knowledge base dedicated to the reliability of high-voltage substations and an associated database. In 1998, analysis of feedback from studies carried out with TOPASE determined several evolutions that are considered desirable. Specifications for all these changes were drawn up early in 1999 and will be implemented in the industrial version of the tool before the end of the year. Approximately ten studies were carried out in 1997-1998 with TOPASE for EDF. They have generally helped operators make and justify their decisions.
{"title":"Power quality: increasing reliability of power substations","authors":"J. Pompee, I. Renault, M. Estévez, F. Martin","doi":"10.1109/PTC.1999.826651","DOIUrl":"https://doi.org/10.1109/PTC.1999.826651","url":null,"abstract":"In the context of deregulation of the electricity market, a special effort must be made to guarantee a high level of system reliability and supply quality. EDF has developed a tool called TOPASE for characterizing faults in electric power supply, particularly in terms of frequency and duration of power cuts at substations. It is designed around a knowledge base dedicated to the reliability of high-voltage substations and an associated database. In 1998, analysis of feedback from studies carried out with TOPASE determined several evolutions that are considered desirable. Specifications for all these changes were drawn up early in 1999 and will be implemented in the industrial version of the tool before the end of the year. Approximately ten studies were carried out in 1997-1998 with TOPASE for EDF. They have generally helped operators make and justify their decisions.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"9 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":"125385306","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 work presents a methodology for calculating the optimal generation capacity reserve and siting in power systems planning. The proposed methodology is based on a least-cost planning approach which considers along the planning horizon, the capacity reserve investment costs and the operational expected costs, comprising thermal generation and interruption costs. This problem is solved by using the Benders decomposition technique in which investment and operation subproblems solutions are obtained iteratively and separately thus allowing the use of tailor-made algorithms for each subproblem. The operation subproblem corresponds to a probabilistic evaluation of the minimum operation cost in composite generation/transmission systems, in which the system states are selected through Monte Carlo simulation or state enumeration and the system performance is analysed by a nonlinear optimal power flow solved by an interior point algorithm. The proposed methodology is illustrated in a case study with a modification of the IEEE Reliability Test System (MRTS).
{"title":"Allocation of generation capacity reserve considering the transmission network","authors":"J. Pessanha, A. Melo, D. Falcão","doi":"10.1109/PTC.1999.826519","DOIUrl":"https://doi.org/10.1109/PTC.1999.826519","url":null,"abstract":"Summary form only given. This work presents a methodology for calculating the optimal generation capacity reserve and siting in power systems planning. The proposed methodology is based on a least-cost planning approach which considers along the planning horizon, the capacity reserve investment costs and the operational expected costs, comprising thermal generation and interruption costs. This problem is solved by using the Benders decomposition technique in which investment and operation subproblems solutions are obtained iteratively and separately thus allowing the use of tailor-made algorithms for each subproblem. The operation subproblem corresponds to a probabilistic evaluation of the minimum operation cost in composite generation/transmission systems, in which the system states are selected through Monte Carlo simulation or state enumeration and the system performance is analysed by a nonlinear optimal power flow solved by an interior point algorithm. The proposed methodology is illustrated in a case study with a modification of the IEEE Reliability Test System (MRTS).","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"69 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":"125444571","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}
N. Malheiro, Z. Vale, C. Ramos, A. Silva, A. Marques
Artificial intelligence techniques have been used for solving power systems problems for some years now. Expert systems in particular were of increasing importance in this area. Nevertheless, conceptual expert systems' capabilities have not yet been totally explored. Their ability to represent knowledge in a symbolic form thus allowing the explanation of its every behavior, justifying it with the knowledge it encodes is an example of neglected expert systems' possibilities. Regarding expert systems with real-time design requirements, the enabling of effective explanation features imposes several important constraints that must be taken into account. This paper presents an explanation mechanism that has been designed and implemented to be used by SPARSE, an expert system for intelligent alarm processing and power restoration aid which is running online in a Portuguese transmission control center. This explanation mechanism is intended for use in the real-time expert system with minimum of disturbances. It is also intended to work as a server, making explanations available to any application that requires them, be it a graphical user interface, a tutor module or any other.
{"title":"Providing explanations in a real-time expert system for control center operator assistance","authors":"N. Malheiro, Z. Vale, C. Ramos, A. Silva, A. Marques","doi":"10.1109/PTC.1999.826614","DOIUrl":"https://doi.org/10.1109/PTC.1999.826614","url":null,"abstract":"Artificial intelligence techniques have been used for solving power systems problems for some years now. Expert systems in particular were of increasing importance in this area. Nevertheless, conceptual expert systems' capabilities have not yet been totally explored. Their ability to represent knowledge in a symbolic form thus allowing the explanation of its every behavior, justifying it with the knowledge it encodes is an example of neglected expert systems' possibilities. Regarding expert systems with real-time design requirements, the enabling of effective explanation features imposes several important constraints that must be taken into account. This paper presents an explanation mechanism that has been designed and implemented to be used by SPARSE, an expert system for intelligent alarm processing and power restoration aid which is running online in a Portuguese transmission control center. This explanation mechanism is intended for use in the real-time expert system with minimum of disturbances. It is also intended to work as a server, making explanations available to any application that requires them, be it a graphical user interface, a tutor module or any other.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"130 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":"126623872","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}
Scheduling of generating units for preventive maintenance plays an important role in the economical and reliable operation of power systems. Based on the observation, the maintenance scheduling of generating units and the makespan minimization on parallel machines are equivalent problems. An effective approximation algorithm is presented both for the levelized reserve and the levelized risk scheduling. A demonstrative example shows that the algorithm can provide a substantial levelization of the risk improving, the reliability of the power system considerably.
{"title":"Levelized risk scheduling for preventive maintenance","authors":"L. Varga, Z. Soós, J. Zsigmond","doi":"10.1109/PTC.1999.826694","DOIUrl":"https://doi.org/10.1109/PTC.1999.826694","url":null,"abstract":"Scheduling of generating units for preventive maintenance plays an important role in the economical and reliable operation of power systems. Based on the observation, the maintenance scheduling of generating units and the makespan minimization on parallel machines are equivalent problems. An effective approximation algorithm is presented both for the levelized reserve and the levelized risk scheduling. A demonstrative example shows that the algorithm can provide a substantial levelization of the risk improving, the reliability of the power system considerably.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"26 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":"121537351","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 weekly streamflow forecasting model based on linear ARMA (p, q) models, considering both periodic and nonperiodic models. For each week, fifty possible models are automatically analyzed. The best modeling and parameter estimation are chosen based on the minimum square mean forecast error of the whole time series. The proposed model, which has been validated by the Brazilian Multi-Utility Hydrological Studies Working Group, is illustrated in case studies with several hydraulic plants of the Brazilian Southern, Southeastern, North and Northeastern systems.
{"title":"Periodic ARMA models applied to weekly streamflow forecasts","authors":"M. Maceira, J. M. Damázio, A. Ghirardi, H. Dantas","doi":"10.1109/PTC.1999.826517","DOIUrl":"https://doi.org/10.1109/PTC.1999.826517","url":null,"abstract":"This paper presents a weekly streamflow forecasting model based on linear ARMA (p, q) models, considering both periodic and nonperiodic models. For each week, fifty possible models are automatically analyzed. The best modeling and parameter estimation are chosen based on the minimum square mean forecast error of the whole time series. The proposed model, which has been validated by the Brazilian Multi-Utility Hydrological Studies Working Group, is illustrated in case studies with several hydraulic plants of the Brazilian Southern, Southeastern, North and Northeastern systems.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"65 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":"120961887","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}
The resonance damping of parallel hybrid filters is analyzed. Active filters can be made to behave as variable resistances and/or inductances when they are connected in power systems; and the operating condition of the complete system can be adjusted dynamically to damp resonance. The effect of the hybrid filter configuration and the control strategy has been evaluated on the resonance damping, as well as harmonic filtering. The frequency characteristics of three parallel hybrid filters topologies are discussed. The principles are validated by simulation and key time-domain results are presented.
{"title":"Comparative study of parallel hybrid filters in resonance damping","authors":"R. Li, A. R. Johns, M. Elkateb, F. Robinson","doi":"10.1109/PTC.1999.826662","DOIUrl":"https://doi.org/10.1109/PTC.1999.826662","url":null,"abstract":"The resonance damping of parallel hybrid filters is analyzed. Active filters can be made to behave as variable resistances and/or inductances when they are connected in power systems; and the operating condition of the complete system can be adjusted dynamically to damp resonance. The effect of the hybrid filter configuration and the control strategy has been evaluated on the resonance damping, as well as harmonic filtering. The frequency characteristics of three parallel hybrid filters topologies are discussed. The principles are validated by simulation and key time-domain results are presented.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"53 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":"121040191","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}
The European power companies are concentrating their efforts primarily at increasing the competitive edge of their companies by means of cost optimization programs, leaving very little free space for new power generation techniques. Fuel cells are a new and promising technology. This article illustrates that there are good opportunities for fuel cells to gain a foothold in the market, even under the pressure of competitive conditions. The retail market in particular offers excellent preconditions for this undertaking. Success decisively depends on the development of cost-optimized systems which can be installed in the user's plant at a low expenditure.
{"title":"The role of the power companies in the fuel cell market","authors":"M. Pokojski","doi":"10.1109/PTC.1999.826484","DOIUrl":"https://doi.org/10.1109/PTC.1999.826484","url":null,"abstract":"The European power companies are concentrating their efforts primarily at increasing the competitive edge of their companies by means of cost optimization programs, leaving very little free space for new power generation techniques. Fuel cells are a new and promising technology. This article illustrates that there are good opportunities for fuel cells to gain a foothold in the market, even under the pressure of competitive conditions. The retail market in particular offers excellent preconditions for this undertaking. Success decisively depends on the development of cost-optimized systems which can be installed in the user's plant at a low expenditure.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"16 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113941188","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 the present, paper the problem of minimum losses operation of automated electrical distribution networks is dealt with. Automation implies that remote control of tie-switches and capacitor banks is possible. To speed the overall procedure a fast network solution method for local search algorithms is also presented. To prove the efficiency of the proposed method a tabu search algorithm has been implemented. The evaluation of power losses and voltage drop has been done using dynamic data structures for the network representation. Test results on a large distribution network are presented and commented.
{"title":"An efficient tabu search approach for optimal operation of MV distribution networks using a past evaluation of power losses","authors":"A. Augugliaro, L. Dusonchet, E. Riva Sanseverino","doi":"10.1109/PTC.1999.826690","DOIUrl":"https://doi.org/10.1109/PTC.1999.826690","url":null,"abstract":"In the present, paper the problem of minimum losses operation of automated electrical distribution networks is dealt with. Automation implies that remote control of tie-switches and capacitor banks is possible. To speed the overall procedure a fast network solution method for local search algorithms is also presented. To prove the efficiency of the proposed method a tabu search algorithm has been implemented. The evaluation of power losses and voltage drop has been done using dynamic data structures for the network representation. Test results on a large distribution network are presented and commented.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"126 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":"123766488","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 smart security screening algorithm for dynamic security assessment (DSA) for large scale power systems. The main features of the method are that contingency screening is conducted by using the time domain simulation results, and detailed machine models may be handled with reliable results obtained. Moreover, as the proposed screening algorithm uses a different stability analysis method for different screening step, it combines the strength of all the methods and overcomes the shortcomings in the case of only using one of them. Since largely stable and unstable contingencies are filtered out at early steps in the analysis, the computation time can be reduced significantly. Also the screening algorithm is easily integrated into the existing time domain simulation program.
{"title":"A smart security screening approach for large scale power systems","authors":"Chun-ling Yang, S. Fukui, Y. Kataoka","doi":"10.1109/PTC.1999.826666","DOIUrl":"https://doi.org/10.1109/PTC.1999.826666","url":null,"abstract":"This paper presents a smart security screening algorithm for dynamic security assessment (DSA) for large scale power systems. The main features of the method are that contingency screening is conducted by using the time domain simulation results, and detailed machine models may be handled with reliable results obtained. Moreover, as the proposed screening algorithm uses a different stability analysis method for different screening step, it combines the strength of all the methods and overcomes the shortcomings in the case of only using one of them. Since largely stable and unstable contingencies are filtered out at early steps in the analysis, the computation time can be reduced significantly. Also the screening algorithm is easily integrated into the existing time domain simulation program.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"538 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113996039","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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