E. De Tuglie, M. Dicorato, M. La Scala, P. Scarpellini
Summary form only given. The aim of this paper is to introduce a new methodology, based on dynamic optimization, for assessing preventive control actions to guarantee dynamic security of power systems. In order to mitigate the effect of a contingency, in terms of steady-state or transient violation such as overloads, unacceptable transient voltage dips, system instability, preventive actions are applied as soon as a potentially dangerous violation is detected during a contingency screening. The proposed approach entails the ability to force the system trajectories in an acceptable state space domain under a set of severe but credible contingencies and gives indications about preventive actions when necessary. The approach is sufficiently general to improve the transient behavior of a power system with regard to different objectives such as: to enforce angle stability of the system constraining rotor angle deviations and minimizing the integral of transient kinetic energy across the whole trajectory; and to avoid transient voltage stability using a signal energy based on an integral form of the voltage magnitude at each bus of the system. This methodology consists of an optimization procedure where: the objective function is aimed at minimizing control action efforts; inequality constraints confine the trajectory of the system in a practical domain of the state space ensuring a feasible behavior of the system, power quality, etc.; and equality constraints derive from the discretization of the differential-algebraic equations of the power system sparse representation.
{"title":"Online dynamic security control in a large scale power system","authors":"E. De Tuglie, M. Dicorato, M. La Scala, P. Scarpellini","doi":"10.1109/PTC.1999.826665","DOIUrl":"https://doi.org/10.1109/PTC.1999.826665","url":null,"abstract":"Summary form only given. The aim of this paper is to introduce a new methodology, based on dynamic optimization, for assessing preventive control actions to guarantee dynamic security of power systems. In order to mitigate the effect of a contingency, in terms of steady-state or transient violation such as overloads, unacceptable transient voltage dips, system instability, preventive actions are applied as soon as a potentially dangerous violation is detected during a contingency screening. The proposed approach entails the ability to force the system trajectories in an acceptable state space domain under a set of severe but credible contingencies and gives indications about preventive actions when necessary. The approach is sufficiently general to improve the transient behavior of a power system with regard to different objectives such as: to enforce angle stability of the system constraining rotor angle deviations and minimizing the integral of transient kinetic energy across the whole trajectory; and to avoid transient voltage stability using a signal energy based on an integral form of the voltage magnitude at each bus of the system. This methodology consists of an optimization procedure where: the objective function is aimed at minimizing control action efforts; inequality constraints confine the trajectory of the system in a practical domain of the state space ensuring a feasible behavior of the system, power quality, etc.; and equality constraints derive from the discretization of the differential-algebraic equations of the power system sparse representation.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"40 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":"133173039","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}
Contingency analysis is a very demanding task in online operation of electric power systems. Amongst the many approaches proposed in literature, the application of artificial neural networks (ANN) showed promising performances, but it often failed to cope with the huge size and the large number of operative states of the real power systems. This paper presents a fast online method based on an original progressive learning ANN. Firstly, the influence zone of each outage is located. Then, a dedicated ANN is trained to forecast the post-fault values of critical line flows and bus voltages. A progressive learning variant of the radial basis function network allows fast and adaptive learning of the pre/post-fault relationships. Tests carried out on a realistic simulator based on the IEEE 118-bus system proved the feasibility of the proposed method.
{"title":"Fast contingency analysis by means of a progressive learning neural network","authors":"E. Bompard, G. Chicco, R. Napoli, F. Piglione","doi":"10.1109/PTC.1999.826564","DOIUrl":"https://doi.org/10.1109/PTC.1999.826564","url":null,"abstract":"Contingency analysis is a very demanding task in online operation of electric power systems. Amongst the many approaches proposed in literature, the application of artificial neural networks (ANN) showed promising performances, but it often failed to cope with the huge size and the large number of operative states of the real power systems. This paper presents a fast online method based on an original progressive learning ANN. Firstly, the influence zone of each outage is located. Then, a dedicated ANN is trained to forecast the post-fault values of critical line flows and bus voltages. A progressive learning variant of the radial basis function network allows fast and adaptive learning of the pre/post-fault relationships. Tests carried out on a realistic simulator based on the IEEE 118-bus system proved the feasibility of the proposed method.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"17 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":"127070183","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}
Meshed underground networks pose particular problems for network protection. If distance protection is used to protect cable networks, a good knowledge of the impedances is important. It is not possible to give a simple relation for the sequence impedances for all types of single core (single-phase) cables if the fault is on the underground line itself. This is due to the fact that, for this case, 6 or 7 independent conductors [3 phases+3 screens+(optional) 1 ground wire] have to be taken into account. This paper presents a model able to determine the impedances seen by distance protections for faults on the cable and discusses the findings.
{"title":"Calculation of the impedances of underground lines seen by distance protections","authors":"V. Leitloff, X. Bourgent, G. Dubne","doi":"10.1109/PTC.1999.826640","DOIUrl":"https://doi.org/10.1109/PTC.1999.826640","url":null,"abstract":"Meshed underground networks pose particular problems for network protection. If distance protection is used to protect cable networks, a good knowledge of the impedances is important. It is not possible to give a simple relation for the sequence impedances for all types of single core (single-phase) cables if the fault is on the underground line itself. This is due to the fact that, for this case, 6 or 7 independent conductors [3 phases+3 screens+(optional) 1 ground wire] have to be taken into account. This paper presents a model able to determine the impedances seen by distance protections for faults on the cable and discusses the findings.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"64 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":"114644050","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 this paper an overview of the behavior of an induction motor when it is supplied from a voltage controlled current regulated inverter is presented. The objective is to show that in this condition, the motor behaves very closely to when it is supplied from the mains. In addition, it is emphasized that unlike the other types of inverters-voltage source or current source, PWM inverters-voltage and current waveforms at motor terminals are nearly sinusoidal and the harmonic content of voltage and current is very low. In this paper, only one type of current regulator is discussed (free running hysteresis current regulator) but other types of regulator such as fixed frequency hysteresis regulator could be used in the system. The simulation result depicts the start-up and loading characteristic of the motor. These results could be compared to those of an induction motor fed from mains supply.
{"title":"Behavior of an induction motor supplied from a voltage controlled current regulated PWM inverter","authors":"S. H. Hosscini, S. Khanmohammasi, H. Javidnia","doi":"10.1109/PTC.1999.826525","DOIUrl":"https://doi.org/10.1109/PTC.1999.826525","url":null,"abstract":"In this paper an overview of the behavior of an induction motor when it is supplied from a voltage controlled current regulated inverter is presented. The objective is to show that in this condition, the motor behaves very closely to when it is supplied from the mains. In addition, it is emphasized that unlike the other types of inverters-voltage source or current source, PWM inverters-voltage and current waveforms at motor terminals are nearly sinusoidal and the harmonic content of voltage and current is very low. In this paper, only one type of current regulator is discussed (free running hysteresis current regulator) but other types of regulator such as fixed frequency hysteresis regulator could be used in the system. The simulation result depicts the start-up and loading characteristic of the motor. These results could be compared to those of an induction motor fed from mains supply.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"42 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":"123681533","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 performance and dynamic characteristic of a solid-state VAr compensator controlled by a neural network is presented and analyzed. Neural network based indirect model reference adaptive control (NN-MRAC) theory is used to design the multioutput nonlinear controller structure. Simulation results of the closed loop control system using a multioutput nonlinear neural network controller demonstrate desirable reactive power compensation and voltage regulation.
{"title":"Dynamic identification and control of PWM inverter VAr compensator using neural network","authors":"S. Hosseini, S. H. Tonekaboni","doi":"10.1109/PTC.1999.826700","DOIUrl":"https://doi.org/10.1109/PTC.1999.826700","url":null,"abstract":"The performance and dynamic characteristic of a solid-state VAr compensator controlled by a neural network is presented and analyzed. Neural network based indirect model reference adaptive control (NN-MRAC) theory is used to design the multioutput nonlinear controller structure. Simulation results of the closed loop control system using a multioutput nonlinear neural network controller demonstrate desirable reactive power compensation and voltage regulation.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"2 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":"124845119","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 scope of the move towards the implementation of market mechanisms, new tariffs schemes are necessary in order to remunerate the transmission service. Several tariffs in use include marginal based terms that, however, may be very dependent on load levels or load uncertainties. In this paper we present a fuzzy set based approach to deal with load uncertainties in order to compute local marginal prices. This approach is based on a DC fuzzy optimal power flow algorithm integrating an estimate of active losses. This algorithm is finally integrated in a Monte Carlo simulation tool in order to obtain estimates of average nodal prices considering component outages.
{"title":"Impact of load uncertainties in spot prices","authors":"J. Saraiva","doi":"10.1109/PTC.1999.826588","DOIUrl":"https://doi.org/10.1109/PTC.1999.826588","url":null,"abstract":"In the scope of the move towards the implementation of market mechanisms, new tariffs schemes are necessary in order to remunerate the transmission service. Several tariffs in use include marginal based terms that, however, may be very dependent on load levels or load uncertainties. In this paper we present a fuzzy set based approach to deal with load uncertainties in order to compute local marginal prices. This approach is based on a DC fuzzy optimal power flow algorithm integrating an estimate of active losses. This algorithm is finally integrated in a Monte Carlo simulation tool in order to obtain estimates of average nodal prices considering component outages.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"32 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":"125021842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An approach based on transportation technique for economic dispatching of a generation-transmission composite system is presented. Component outages are considered. Through application of the Monte Carlo simulation and the minimum-cost maximum-flow algorithm, this approach searches the cheapest (minimum cost) path of a graph and then determines the maximum flow (minimum capacity of the branches of the cheapest path) for power dispatching. Through repetitive application of the algorithm, a near optimal power flow pattern can be determined and thus security constrained economic dispatch is obtained.
{"title":"A network-flow approach for security constrained economic dispatch of power systems","authors":"C. Su, Ying-Chang Hsiao, Yuh-Chyuan Su","doi":"10.1109/PTC.1999.826623","DOIUrl":"https://doi.org/10.1109/PTC.1999.826623","url":null,"abstract":"An approach based on transportation technique for economic dispatching of a generation-transmission composite system is presented. Component outages are considered. Through application of the Monte Carlo simulation and the minimum-cost maximum-flow algorithm, this approach searches the cheapest (minimum cost) path of a graph and then determines the maximum flow (minimum capacity of the branches of the cheapest path) for power dispatching. Through repetitive application of the algorithm, a near optimal power flow pattern can be determined and thus security constrained economic dispatch is obtained.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"105 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":"129449030","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}
P. Ekel, L. Terra, C.C. Fontes, J. Souza, V. Popov
Two lines of improving the validity and efficiency in solving problems of network reconfiguration in distribution systems are considered. One line is associated with taking into account a power system reaction while minimizing power or energy losses. Different techniques for constructing power system functional equivalents are considered and illustrated. Another line is related to formulating the problems within the framework of a multicriteria optimization model to consider and to minimize diverse indices. Analysis of the model is based on the Bellman-Zadeh approach to decision making in a fuzzy environment.
{"title":"Talking into account power system reaction in problems of multicriteria optimizing network configuration in distribution systems","authors":"P. Ekel, L. Terra, C.C. Fontes, J. Souza, V. Popov","doi":"10.1109/PTC.1999.826498","DOIUrl":"https://doi.org/10.1109/PTC.1999.826498","url":null,"abstract":"Two lines of improving the validity and efficiency in solving problems of network reconfiguration in distribution systems are considered. One line is associated with taking into account a power system reaction while minimizing power or energy losses. Different techniques for constructing power system functional equivalents are considered and illustrated. Another line is related to formulating the problems within the framework of a multicriteria optimization model to consider and to minimize diverse indices. Analysis of the model is based on the Bellman-Zadeh approach to decision making in a fuzzy environment.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"79 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":"129453593","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}
A. Tungkanawanich, Z. Kawasaki, K. Matsuura, H. Kuno
Transients normally contain information that is helpful to diagnose the cause and aspect of the fault. This experiment is conducted with the objective of studying the basic knowledge of fault features and hopefully useful to get more precise in discriminating fault causes. Ground faults are concentrated in this paper because they are known as the most frequent ones occurring on distribution lines. The results are compared with those from actual fault and computer simulation. The authors also conduct the time-frequency analysis of dynamic spectrum of transients of various fault causes by means of wavelet transform for explaining fault phenomena.
{"title":"Experimental study for transient phenomena of ground faults on distribution lines based on various fault causes","authors":"A. Tungkanawanich, Z. Kawasaki, K. Matsuura, H. Kuno","doi":"10.1109/PTC.1999.826577","DOIUrl":"https://doi.org/10.1109/PTC.1999.826577","url":null,"abstract":"Transients normally contain information that is helpful to diagnose the cause and aspect of the fault. This experiment is conducted with the objective of studying the basic knowledge of fault features and hopefully useful to get more precise in discriminating fault causes. Ground faults are concentrated in this paper because they are known as the most frequent ones occurring on distribution lines. The results are compared with those from actual fault and computer simulation. The authors also conduct the time-frequency analysis of dynamic spectrum of transients of various fault causes by means of wavelet transform for explaining fault phenomena.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129668401","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 two new performance indices for contingency analysis in a composite electric power system. The proposed indices are derived from active power transmission losses that do not require additional parameters. They can be used effectively for line overloading and bus voltage limit violation performance indices. Their effects are tested on an IEEE RTS and the results have shown that they can be used effectively instead of the conventional ones.
{"title":"Contingency selection based on real power transmission losses","authors":"R. Çağlar, A. Ozdemir, F. Mekić","doi":"10.1109/PTC.1999.826548","DOIUrl":"https://doi.org/10.1109/PTC.1999.826548","url":null,"abstract":"This paper presents two new performance indices for contingency analysis in a composite electric power system. The proposed indices are derived from active power transmission losses that do not require additional parameters. They can be used effectively for line overloading and bus voltage limit violation performance indices. Their effects are tested on an IEEE RTS and the results have shown that they can be used effectively instead of the conventional ones.","PeriodicalId":101688,"journal":{"name":"PowerTech Budapest 99. Abstract Records. (Cat. No.99EX376)","volume":"6 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":"127462904","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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