Pub Date : 1997-05-11DOI: 10.1109/PICA.1997.599378
Hong-Tzer Yang, Yann-Chang Huang
To serve as an intelligent decision support for power transformer fault diagnosis, a new self-organizing polynomial networks (SOPNs) modeling technique is proposed and implemented in this paper. The technique heuristically formulates the modeling problem into a hierarchical architecture with several layers of functional nodes of simple low-order polynomials. The networks handle the numerical, complicated, and uncertain relationships of dissolved gas contents of the transformers to fault conditions. Verification of the proposed approach has been accomplished through a number of experiments using practical numerical diagnostic records of the transformers of Taiwan power (Taipower) systems. In comparison to the results obtained from the conventional dissolved gas analysis (DGA) and the artificial neural networks (ANNs) classification methods, the proposed method has been shown to possess far superior performances both in developing the diagnosis system and in identifying the practical transformer fault cases.
{"title":"Intelligent decision support for diagnosis of incipient transformer faults using self-organizing polynomial networks","authors":"Hong-Tzer Yang, Yann-Chang Huang","doi":"10.1109/PICA.1997.599378","DOIUrl":"https://doi.org/10.1109/PICA.1997.599378","url":null,"abstract":"To serve as an intelligent decision support for power transformer fault diagnosis, a new self-organizing polynomial networks (SOPNs) modeling technique is proposed and implemented in this paper. The technique heuristically formulates the modeling problem into a hierarchical architecture with several layers of functional nodes of simple low-order polynomials. The networks handle the numerical, complicated, and uncertain relationships of dissolved gas contents of the transformers to fault conditions. Verification of the proposed approach has been accomplished through a number of experiments using practical numerical diagnostic records of the transformers of Taiwan power (Taipower) systems. In comparison to the results obtained from the conventional dissolved gas analysis (DGA) and the artificial neural networks (ANNs) classification methods, the proposed method has been shown to possess far superior performances both in developing the diagnosis system and in identifying the practical transformer fault cases.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121780806","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 : 1997-05-11DOI: 10.1109/PICA.1997.599405
A.B.R. Kumar, A. Brandwajn, A. Ipakchi, R. Adapa
This paper describes an integrated framework for power system dynamic security analysis in both online and the offline modes. In the online mode, the framework allows for the use of efficient techniques for the pre-selection screening and ranking of contingencies and the calculation of relevant operating limits. In the offline mode, this framework can help the operations planner by: providing a friendly graphical user interface; guiding a systematic progression in the decision making process; preparing relevant combinations of available options and adverse power system operating conditions; minimizing inadvertant omissions; performing routine data manipulation; archiving and retrieving information; checking the input data for completeness, consistency and reasonability; and organizing the output results from various cases.
{"title":"Integrated framework for dynamic security analysis","authors":"A.B.R. Kumar, A. Brandwajn, A. Ipakchi, R. Adapa","doi":"10.1109/PICA.1997.599405","DOIUrl":"https://doi.org/10.1109/PICA.1997.599405","url":null,"abstract":"This paper describes an integrated framework for power system dynamic security analysis in both online and the offline modes. In the online mode, the framework allows for the use of efficient techniques for the pre-selection screening and ranking of contingencies and the calculation of relevant operating limits. In the offline mode, this framework can help the operations planner by: providing a friendly graphical user interface; guiding a systematic progression in the decision making process; preparing relevant combinations of available options and adverse power system operating conditions; minimizing inadvertant omissions; performing routine data manipulation; archiving and retrieving information; checking the input data for completeness, consistency and reasonability; and organizing the output results from various cases.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124623855","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 : 1997-05-11DOI: 10.1109/PICA.1997.599403
R. A. Ponrajah, F. Galiana
Optimal dispatch systems at hydroelectric power plants manage the energy conversion process such that, under all conditions, the station efficiency is maximised. This paper describes an optimal dispatch system which has proven to be successful at two installations, one on the Nipigon river controlling three stations near Thunder Bay, Ontario, and the other at R.H. Saunders generating station on the St. Lawrence river near Cornwall, Ontario, Canada. The validated benefits amount to 15GWh per year, which is about 0.25% of the annual production at the respective stations. Secondary benefits arising from this system include increased decision making assistance, improved accessibility to plant data and an overall improvement in operational performance.
{"title":"Systems to optimise conversion efficiencies at Ontario Hydro's hydroelectric plants","authors":"R. A. Ponrajah, F. Galiana","doi":"10.1109/PICA.1997.599403","DOIUrl":"https://doi.org/10.1109/PICA.1997.599403","url":null,"abstract":"Optimal dispatch systems at hydroelectric power plants manage the energy conversion process such that, under all conditions, the station efficiency is maximised. This paper describes an optimal dispatch system which has proven to be successful at two installations, one on the Nipigon river controlling three stations near Thunder Bay, Ontario, and the other at R.H. Saunders generating station on the St. Lawrence river near Cornwall, Ontario, Canada. The validated benefits amount to 15GWh per year, which is about 0.25% of the annual production at the respective stations. Secondary benefits arising from this system include increased decision making assistance, improved accessibility to plant data and an overall improvement in operational performance.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130883367","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 : 1997-05-11DOI: 10.1109/PICA.1997.599379
K. Narendra, K. Khorasani, V. Sood, R. Patel
This paper describes an intelligent current controller for the fast and flexible control of an HVDC transmission link using artificial neural network (ANN) and fuzzy logic (FL) paradigms. A simple yet effective ANN architecture is presented with online adaptation of the activation function and learning parameters. Two methods of adapting the learning parameters are presented. In the first method, a heuristic approach to evaluate the learning rate as a polynomial of an energy function is considered. In the second method, a FL based online adaptation of the learning parameters is discussed. Performance of ANN, ANN-FL based and PI controllers are compared. A feasibility analysis is carried out to implement the proposed neural controller algorithm in real-time.
{"title":"Intelligent current controller for an HVDC transmission link","authors":"K. Narendra, K. Khorasani, V. Sood, R. Patel","doi":"10.1109/PICA.1997.599379","DOIUrl":"https://doi.org/10.1109/PICA.1997.599379","url":null,"abstract":"This paper describes an intelligent current controller for the fast and flexible control of an HVDC transmission link using artificial neural network (ANN) and fuzzy logic (FL) paradigms. A simple yet effective ANN architecture is presented with online adaptation of the activation function and learning parameters. Two methods of adapting the learning parameters are presented. In the first method, a heuristic approach to evaluate the learning rate as a polynomial of an energy function is considered. In the second method, a FL based online adaptation of the learning parameters is discussed. Performance of ANN, ANN-FL based and PI controllers are compared. A feasibility analysis is carried out to implement the proposed neural controller algorithm in real-time.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126730312","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 : 1997-05-11DOI: 10.1109/PICA.1997.599385
T. Kostic, R. Cherkaoui, A. Germond, P. Pruvot
This paper deals with the conceptual design of a Decision Aid Function For Restoration (DAFFOR) after major black-outs, and in particular with real time considerations. Some important characteristics of the proposed DAFFOR are: (a) capability of taking into account the dynamic evolution of the network state, due to either a control action or an unforeseen event; (b) interactive mode, which permits users to request a validation of their own suggestion; and (c) coupling with an internal dynamic simulator which is solicited to validate any suggestion. At present, the DAFFOR is coupled with the French National Utility Operator Training Simulator (EDF OTS). After intensive testing within the OTS environment, the operational version of the DAFFOR is developed.
{"title":"Decision Aid Function for Restoration of transmission power systems: conceptual design and real time considerations","authors":"T. Kostic, R. Cherkaoui, A. Germond, P. Pruvot","doi":"10.1109/PICA.1997.599385","DOIUrl":"https://doi.org/10.1109/PICA.1997.599385","url":null,"abstract":"This paper deals with the conceptual design of a Decision Aid Function For Restoration (DAFFOR) after major black-outs, and in particular with real time considerations. Some important characteristics of the proposed DAFFOR are: (a) capability of taking into account the dynamic evolution of the network state, due to either a control action or an unforeseen event; (b) interactive mode, which permits users to request a validation of their own suggestion; and (c) coupling with an internal dynamic simulator which is solicited to validate any suggestion. At present, the DAFFOR is coupled with the French National Utility Operator Training Simulator (EDF OTS). After intensive testing within the OTS environment, the operational version of the DAFFOR is developed.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115267680","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 : 1997-05-11DOI: 10.1109/PICA.1997.599383
A.G. Expsito, A. Abur
Network observability analysis is formulated in a way to incorporate the conventional as well as unconventional measurements, including line currents. This formulation has two essential advantages over the existing methods of network observability analysis: (1) it detects not only unobservability but also uniqueness of the observed state, and (2) it can directly identify the unobservable or nonuniquely observable branches without having to remove the irrelevant injections in an iterative manner. In addition, unlike the numerical observability analysis methods proposed so far, it can readily identify residual spread components and critical measurements. The proposed formulation is implemented and tested on sample power systems.
{"title":"Generalized observability analysis and measurement classification","authors":"A.G. Expsito, A. Abur","doi":"10.1109/PICA.1997.599383","DOIUrl":"https://doi.org/10.1109/PICA.1997.599383","url":null,"abstract":"Network observability analysis is formulated in a way to incorporate the conventional as well as unconventional measurements, including line currents. This formulation has two essential advantages over the existing methods of network observability analysis: (1) it detects not only unobservability but also uniqueness of the observed state, and (2) it can directly identify the unobservable or nonuniquely observable branches without having to remove the irrelevant injections in an iterative manner. In addition, unlike the numerical observability analysis methods proposed so far, it can readily identify residual spread components and critical measurements. The proposed formulation is implemented and tested on sample power systems.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115543226","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 : 1997-05-11DOI: 10.1109/PICA.1997.599407
M. Laufenberg, M. Pai
The transient stability of power systems is investigated using a new analytical tool. Instead of computing the sensitivities of energy margins, trajectory sensitivity functions of the post-fault system with respect to parameters are computed. The goal is to find how sensitive the trajectories of each state are to variations in system parameters. When the system becomes more stressed, the state trajectories become more sensitive to variations in parameters. Thus these trajectory sensitivities can be used as a measure of system security. This concept is illustrated on the IEEE single- and seventeen-machine systems, and it is shown that dynamic sensitivity functions can also be applied to systems of differential-algebraic equations where the TEF method has limitations.
{"title":"A new approach to dynamic security assessment using trajectory sensitivities","authors":"M. Laufenberg, M. Pai","doi":"10.1109/PICA.1997.599407","DOIUrl":"https://doi.org/10.1109/PICA.1997.599407","url":null,"abstract":"The transient stability of power systems is investigated using a new analytical tool. Instead of computing the sensitivities of energy margins, trajectory sensitivity functions of the post-fault system with respect to parameters are computed. The goal is to find how sensitive the trajectories of each state are to variations in system parameters. When the system becomes more stressed, the state trajectories become more sensitive to variations in parameters. Thus these trajectory sensitivities can be used as a measure of system security. This concept is illustrated on the IEEE single- and seventeen-machine systems, and it is shown that dynamic sensitivity functions can also be applied to systems of differential-algebraic equations where the TEF method has limitations.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127054566","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 : 1997-05-11DOI: 10.1109/PICA.1997.599428
H. Glavitsch
This paper studies congestion management based on congestion pricing as may be done by an independent power system operator. Four main concepts are discussed: congestion pricing can lead to the same solution as an optimal power flow; pricing need not have cost information available; good estimates of nonlinear cost coefficients are necessary; and pricing for congestion management is separable from pricing for the purpose of transmission network revenue reconciliation. Emphasis is on the determination of sufficient information by observation of the behavior of the market to permit optimum pricing without explicit communication among parties, and without generators ever being explicitly concerned about the relief of flow congestion. Results from simulated experiments are presented.
{"title":"Management of multiple congested conditions in unbundled operation of a power system","authors":"H. Glavitsch","doi":"10.1109/PICA.1997.599428","DOIUrl":"https://doi.org/10.1109/PICA.1997.599428","url":null,"abstract":"This paper studies congestion management based on congestion pricing as may be done by an independent power system operator. Four main concepts are discussed: congestion pricing can lead to the same solution as an optimal power flow; pricing need not have cost information available; good estimates of nonlinear cost coefficients are necessary; and pricing for congestion management is separable from pricing for the purpose of transmission network revenue reconciliation. Emphasis is on the determination of sufficient information by observation of the behavior of the market to permit optimum pricing without explicit communication among parties, and without generators ever being explicitly concerned about the relief of flow congestion. Results from simulated experiments are presented.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121775352","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 : 1997-05-11DOI: 10.1109/PICA.1997.599373
M. Marwali, S. M. Shahidehpour
Most unit maintenance scheduling packages consider preventive maintenance schedule of generating units over a one or two year operational planning period in order to minimize the total operating cost while satisfying system energy requirements and maintenance constraints. In a global maintenance scheduling problem, the authors propose to consider transmission line maintenance scheduling and line capacity limits along with generation and line outages. The inclusion of transmission and network constraints in generating unit maintenance will increase the complexity of the problem, so they propose to decompose the global generator/transmission scheduling problem into a master problem and sub-problems using Benders decomposition. In the first stage, a master problem is solved to determine a solution for maintenance schedule decision variables. In the second stage, sub-problems are solved to minimize operating costs while satisfying the network constraints. Benders cuts based on the solution of the sub-problem are introduced to the master problem for improving the existing solution. The iterative procedure continues until an optimal or near optimal solution is found.
{"title":"Integrated generation and transmission maintenance scheduling with network constraints","authors":"M. Marwali, S. M. Shahidehpour","doi":"10.1109/PICA.1997.599373","DOIUrl":"https://doi.org/10.1109/PICA.1997.599373","url":null,"abstract":"Most unit maintenance scheduling packages consider preventive maintenance schedule of generating units over a one or two year operational planning period in order to minimize the total operating cost while satisfying system energy requirements and maintenance constraints. In a global maintenance scheduling problem, the authors propose to consider transmission line maintenance scheduling and line capacity limits along with generation and line outages. The inclusion of transmission and network constraints in generating unit maintenance will increase the complexity of the problem, so they propose to decompose the global generator/transmission scheduling problem into a master problem and sub-problems using Benders decomposition. In the first stage, a master problem is solved to determine a solution for maintenance schedule decision variables. In the second stage, sub-problems are solved to minimize operating costs while satisfying the network constraints. Benders cuts based on the solution of the sub-problem are introduced to the master problem for improving the existing solution. The iterative procedure continues until an optimal or near optimal solution is found.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126294050","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 : 1997-05-11DOI: 10.1109/PICA.1997.599418
S. Khaparde, V. Krishna
In the literature, the co-ordination of static VAr compensators (SVC) and power system stabilizers (PSS) using generator speed deviation or modal speeds such as stabilizing signals is shown to damp power system oscillations. Though such schemes are able to damp the SSR modes for small disturbances, they are unable to damp transient SSR due to large disturbances. In this report, an improvement in the control aspect of the SVC at the midpoint of the power transmission line is suggested. This scheme attempts different auxiliary signals that include line current, computed internal frequency and bus angle deviations. A system of configuration similar to IEEE First Bench Mark model is considered, eigenvalue analysis has been carried out and results indicate that bus angle deviation signal as an auxiliary control signal for SVC was able to damp most of the modes leaving some of them still oscillatory. The main feature of the proposed work is to use a combination of the deviation in speed and electrical power output of the generator as input signals to PSS which operates simultaneously along with SVC. Such a simultaneous PSS and SVC scheme is found to improve power system damping under large disturbances, i.e. the growth of system oscillations is arrested. Control simulations are carried out on PSCAD. The efficacy of controllers to damp SSR under steady state and faulted conditions, where one of the torsional modes is excited, is presented and discussed.
{"title":"Simulation of unified static VAr compensator and power system stabilizer for arresting subsynchronous resonance","authors":"S. Khaparde, V. Krishna","doi":"10.1109/PICA.1997.599418","DOIUrl":"https://doi.org/10.1109/PICA.1997.599418","url":null,"abstract":"In the literature, the co-ordination of static VAr compensators (SVC) and power system stabilizers (PSS) using generator speed deviation or modal speeds such as stabilizing signals is shown to damp power system oscillations. Though such schemes are able to damp the SSR modes for small disturbances, they are unable to damp transient SSR due to large disturbances. In this report, an improvement in the control aspect of the SVC at the midpoint of the power transmission line is suggested. This scheme attempts different auxiliary signals that include line current, computed internal frequency and bus angle deviations. A system of configuration similar to IEEE First Bench Mark model is considered, eigenvalue analysis has been carried out and results indicate that bus angle deviation signal as an auxiliary control signal for SVC was able to damp most of the modes leaving some of them still oscillatory. The main feature of the proposed work is to use a combination of the deviation in speed and electrical power output of the generator as input signals to PSS which operates simultaneously along with SVC. Such a simultaneous PSS and SVC scheme is found to improve power system damping under large disturbances, i.e. the growth of system oscillations is arrested. Control simulations are carried out on PSCAD. The efficacy of controllers to damp SSR under steady state and faulted conditions, where one of the torsional modes is excited, is presented and discussed.","PeriodicalId":383749,"journal":{"name":"Proceedings of the 20th International Conference on Power Industry Computer Applications","volume":"209 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131927575","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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