Pub Date : 2002-12-10DOI: 10.1109/LESCPE.2002.1020672
T. Little, S. Sivakumar
This paper presents the optimized conditions for stepped wave inverters in order to minimize the total harmonic distortion present in the output waveform. It is shown that one- and two-level waveforms do not have sufficient degrees of freedom to meet harmonic standards like the IEEE 519. However three-level waveforms can be constructed, which meet such power quality standards and as a result, do not require output filtering.
{"title":"Inverters without filters","authors":"T. Little, S. Sivakumar","doi":"10.1109/LESCPE.2002.1020672","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020672","url":null,"abstract":"This paper presents the optimized conditions for stepped wave inverters in order to minimize the total harmonic distortion present in the output waveform. It is shown that one- and two-level waveforms do not have sufficient degrees of freedom to meet harmonic standards like the IEEE 519. However three-level waveforms can be constructed, which meet such power quality standards and as a result, do not require output filtering.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131554635","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020681
M. Awadallah, M. Morcos
A model-based diagnostic system for stator winding inter-turn faults of PM brushless DC motor drives is presented. A transient model of the drive system is set up and run under different healthy and faulty conditions. The steady-state supply current is selected as the diagnostic signal to compare the healthy operation to the faulty operation under different loads. The supply current signal is transformed to the frequency domain using the discrete Fourier transform (DFT). Appropriate diagnostic indices are extracted from the supply current spectrum to differentiate between healthy and different faulty conditions.
{"title":"Stator-winding fault diagnosis of PM brushless DC motor drives","authors":"M. Awadallah, M. Morcos","doi":"10.1109/LESCPE.2002.1020681","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020681","url":null,"abstract":"A model-based diagnostic system for stator winding inter-turn faults of PM brushless DC motor drives is presented. A transient model of the drive system is set up and run under different healthy and faulty conditions. The steady-state supply current is selected as the diagnostic signal to compare the healthy operation to the faulty operation under different loads. The supply current signal is transformed to the frequency domain using the discrete Fourier transform (DFT). Appropriate diagnostic indices are extracted from the supply current spectrum to differentiate between healthy and different faulty conditions.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127914896","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020666
S. A. Saleh, M. Rahman
This paper presents a model of the power transformer for electromagnetic transient studies, which employs a wavelet filter bank. In this model both the primary and the secondary windings are represented by stages of a wavelet filter bank where the dimensions of such a filter bank depend on the number of turns of primary windings and secondary windings. The basic building block consists of stages of the wavelet filter bank. Transformer total response is composed of the sum of responses of all stages, which depends on the nature of the primary current. Using the wavelet filter model, the losses due to eddy currents, leakage flux, and inrush currents have been studied. The proposed wavelet filter model has been found to be suitable for power transformer inrush currents including high frequency transient effects.
{"title":"Transient model of power transformer using wavelet filter bank","authors":"S. A. Saleh, M. Rahman","doi":"10.1109/LESCPE.2002.1020666","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020666","url":null,"abstract":"This paper presents a model of the power transformer for electromagnetic transient studies, which employs a wavelet filter bank. In this model both the primary and the secondary windings are represented by stages of a wavelet filter bank where the dimensions of such a filter bank depend on the number of turns of primary windings and secondary windings. The basic building block consists of stages of the wavelet filter bank. Transformer total response is composed of the sum of responses of all stages, which depends on the nature of the primary current. Using the wavelet filter model, the losses due to eddy currents, leakage flux, and inrush currents have been studied. The proposed wavelet filter model has been found to be suitable for power transformer inrush currents including high frequency transient effects.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"208 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115902802","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020679
A. Sallam, A.M. Khafaga
This paper argues that the artificial neural network (ANN) is an important technique and can be applied to control voltage instability problems in two ways. The first is to control voltage collapse by using load shedding. In this way the minimum and optimal ratio of load shedding can be calculated. The second is to calculate the reactive power required to control sources in the electric power system. The strengths of this powerful technique lie in its ability for modeling and solving many types of problems. The ANN is designed for those two mentioned ways. A multi-layer feed forward ANN trained with error backpropagation learning is proposed. This network is applied to a stressed power system at different load levels. Simulation results on a test system are reported in this paper.
{"title":"Artificial neural network application to alleviate voltage instability problem","authors":"A. Sallam, A.M. Khafaga","doi":"10.1109/LESCPE.2002.1020679","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020679","url":null,"abstract":"This paper argues that the artificial neural network (ANN) is an important technique and can be applied to control voltage instability problems in two ways. The first is to control voltage collapse by using load shedding. In this way the minimum and optimal ratio of load shedding can be calculated. The second is to calculate the reactive power required to control sources in the electric power system. The strengths of this powerful technique lie in its ability for modeling and solving many types of problems. The ANN is designed for those two mentioned ways. A multi-layer feed forward ANN trained with error backpropagation learning is proposed. This network is applied to a stressed power system at different load levels. Simulation results on a test system are reported in this paper.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"233 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134006862","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020680
C. Paduraru
The article describes the concept of automatic testing of protective relays in power industry. First, the increased need for automatic test modules is explained. Next, a detailed example is provided using the "load encroachment characteristic". Relay settings and testing approach are explained step by step. Finally, the capability of the software is emphasized and conclusions are drawn.
{"title":"Automated testing of protective relays using advanced visual test software","authors":"C. Paduraru","doi":"10.1109/LESCPE.2002.1020680","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020680","url":null,"abstract":"The article describes the concept of automatic testing of protective relays in power industry. First, the increased need for automatic test modules is explained. Next, a detailed example is provided using the \"load encroachment characteristic\". Relay settings and testing approach are explained step by step. Finally, the capability of the software is emphasized and conclusions are drawn.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126333270","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020662
K. Xiong, W. Rosehart
As open access market principles are applied to power systems, stability margins have been steadily decreasing. This has lead to events such as rolling black-outs in several power systems, for example, California, and has generally resulted in increased electricity prices. A novel approach to reduce the tension in electrical systems is to establish a fast acting load control program for price and system stability. This differs from traditional approaches where additional transmission lines and generators need to be installed. Using this approach, load can be modeled and controlled similar to a generator, proving spinning reserve. The paper reviews existing implementations of fast acting load control. Furthermore, in this paper, two Lagrangian based approaches are used to determine optimal locations for fast acting load control. The approaches are formulated to consider economic cost and stability limits. The effects of applying these approaches are analyzed using a 30-bus system, which is derived from the IEEE 30-bus test system.
{"title":"Fast acting load control","authors":"K. Xiong, W. Rosehart","doi":"10.1109/LESCPE.2002.1020662","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020662","url":null,"abstract":"As open access market principles are applied to power systems, stability margins have been steadily decreasing. This has lead to events such as rolling black-outs in several power systems, for example, California, and has generally resulted in increased electricity prices. A novel approach to reduce the tension in electrical systems is to establish a fast acting load control program for price and system stability. This differs from traditional approaches where additional transmission lines and generators need to be installed. Using this approach, load can be modeled and controlled similar to a generator, proving spinning reserve. The paper reviews existing implementations of fast acting load control. Furthermore, in this paper, two Lagrangian based approaches are used to determine optimal locations for fast acting load control. The approaches are formulated to consider economic cost and stability limits. The effects of applying these approaches are analyzed using a 30-bus system, which is derived from the IEEE 30-bus test system.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121431099","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020661
H. Yamin
This paper describes a coordination process between GENCOs and the ISO for congestion management and reducing the risk of failure to supply loads. The algorithm underlining the coordination technique is the security-constrained price-based unit commitment (SPUC) which is implemented in two states. At first, GENCOs apply priced-based unit commitment (without transmission security constraints), schedule their generating units and submit their energy and capacity bids to the ISO for maximizing their revenues. The ISO obtains transmission information as well from TRANSCOs via OASIS. Using the two sets of generation and transmission data, the ISO executes inter-zonal and intra-zonal congestion management and contingency analysis for minimizing line flow violations and the risk supplying loads. As part of this package, the ISO would have a chance to minimize both transmission flow and reactive (bus voltage) violations. If transmission flow violations persist after the adjustments are made, the solution would provide a signal to GENCOs, based on Benders decomposition, for modifying their initial bids. Accordingly, additional constraints will be introduced in GENCOs for rescheduling generating units and submitting modified bids to the ISO.
{"title":"Security-constrained price-based unit commitment in the deregulated power market","authors":"H. Yamin","doi":"10.1109/LESCPE.2002.1020661","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020661","url":null,"abstract":"This paper describes a coordination process between GENCOs and the ISO for congestion management and reducing the risk of failure to supply loads. The algorithm underlining the coordination technique is the security-constrained price-based unit commitment (SPUC) which is implemented in two states. At first, GENCOs apply priced-based unit commitment (without transmission security constraints), schedule their generating units and submit their energy and capacity bids to the ISO for maximizing their revenues. The ISO obtains transmission information as well from TRANSCOs via OASIS. Using the two sets of generation and transmission data, the ISO executes inter-zonal and intra-zonal congestion management and contingency analysis for minimizing line flow violations and the risk supplying loads. As part of this package, the ISO would have a chance to minimize both transmission flow and reactive (bus voltage) violations. If transmission flow violations persist after the adjustments are made, the solution would provide a signal to GENCOs, based on Benders decomposition, for modifying their initial bids. Accordingly, additional constraints will be introduced in GENCOs for rescheduling generating units and submitting modified bids to the ISO.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128149827","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020683
J. Talaq
A systematic procedure to solving complex and multiple fault problems of power systems is proposed in this paper. Complex faults are combinations of different common unsymmetrical faults that occur at a single bus. Multiple faults are a series of complex faults that occur at several buses at the same time. The proposed method utilize the well known bus impedance matrix method for fault analysis. Examples of both types of faults are given to demonstrate the proposed procedure.
{"title":"Complex and multiple unsymmetrical fault analysis","authors":"J. Talaq","doi":"10.1109/LESCPE.2002.1020683","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020683","url":null,"abstract":"A systematic procedure to solving complex and multiple fault problems of power systems is proposed in this paper. Complex faults are combinations of different common unsymmetrical faults that occur at a single bus. Multiple faults are a series of complex faults that occur at several buses at the same time. The proposed method utilize the well known bus impedance matrix method for fault analysis. Examples of both types of faults are given to demonstrate the proposed procedure.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116337202","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020667
M. Skok, D. Skrlec, S. Krajcar
In order to enhance the serviceability in the distribution system genetic algorithm and GIS based method is proposed in this article for planning the link distribution networks. All practical issues such as cost parameters (investments, line losses, maintenance), and technical constraints (voltage drop, thermal limit, reliability) as well as physical routing constraints (obstacles, high cost passages, existing line sections) are taken into consideration. Fuzzy set concept and scenario representation (tree of futures) to model uncertainties, as well as decision making guided by a paradigm of multi-criteria risk analysis are discussed. The merits of the approach are discussed by analyzing its application to a study case based on a real case in a Croatian utility.
{"title":"Genetic algorithm and GIS enhanced long term planning of large link structured distribution systems","authors":"M. Skok, D. Skrlec, S. Krajcar","doi":"10.1109/LESCPE.2002.1020667","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020667","url":null,"abstract":"In order to enhance the serviceability in the distribution system genetic algorithm and GIS based method is proposed in this article for planning the link distribution networks. All practical issues such as cost parameters (investments, line losses, maintenance), and technical constraints (voltage drop, thermal limit, reliability) as well as physical routing constraints (obstacles, high cost passages, existing line sections) are taken into consideration. Fuzzy set concept and scenario representation (tree of futures) to model uncertainties, as well as decision making guided by a paradigm of multi-criteria risk analysis are discussed. The merits of the approach are discussed by analyzing its application to a study case based on a real case in a Croatian utility.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124858748","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 : 2002-12-10DOI: 10.1109/LESCPE.2002.1020687
Z.Q. Wang, S.Z. Zhou, Y.J. Guo
Power quality disturbances are normally recorded by dedicated PQ monitors as sampled points in time. Magnitude is accepted as a significant detection and general classification index in field devices or later assessment analysis. Suitable methods of magnitude characterization are one of the bases of PQD measuring and monitoring. The magnitude of PQD can be determined in several different ways. The RMS voltage, peak voltage and fundamental voltage component are introduced to quantify the voltage severity levels in number of published standards. The paper presents the algorithms of the mentioned approaches implemented in Matlab for quasi real-time situation. The algorithms are FFT-based and/or wavelet transform based. They are validated with the example of the radial test system field voltage sag waveforms provided by the IEEE. The depth-duration characterization of voltage sags is illustrated with the mentioned different approaches. The most appropriate approach is suggested at the end of the paper according to the practical monitoring or measuring requirements. We develop a new PQ monitor with DSP chip infrastructure where all the methods are applied. The proper window length selection and technique to avoid oscillation is also discussed in the rest of the paper. The descriptive information obtained from the magnitude characterization can be used further to extract features for PQD detection and classification.
{"title":"Comparisons on ways of magnitude characterization of power quality disturbances","authors":"Z.Q. Wang, S.Z. Zhou, Y.J. Guo","doi":"10.1109/LESCPE.2002.1020687","DOIUrl":"https://doi.org/10.1109/LESCPE.2002.1020687","url":null,"abstract":"Power quality disturbances are normally recorded by dedicated PQ monitors as sampled points in time. Magnitude is accepted as a significant detection and general classification index in field devices or later assessment analysis. Suitable methods of magnitude characterization are one of the bases of PQD measuring and monitoring. The magnitude of PQD can be determined in several different ways. The RMS voltage, peak voltage and fundamental voltage component are introduced to quantify the voltage severity levels in number of published standards. The paper presents the algorithms of the mentioned approaches implemented in Matlab for quasi real-time situation. The algorithms are FFT-based and/or wavelet transform based. They are validated with the example of the radial test system field voltage sag waveforms provided by the IEEE. The depth-duration characterization of voltage sags is illustrated with the mentioned different approaches. The most appropriate approach is suggested at the end of the paper according to the practical monitoring or measuring requirements. We develop a new PQ monitor with DSP chip infrastructure where all the methods are applied. The proper window length selection and technique to avoid oscillation is also discussed in the rest of the paper. The descriptive information obtained from the magnitude characterization can be used further to extract features for PQD detection and classification.","PeriodicalId":127699,"journal":{"name":"LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122049543","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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