Pub Date : 2014-11-24DOI: 10.1109/NAPS.2014.6965474
Sudipta Ghosh, N. Senroy, S. Kamalasadan
A reduced order linearized dynamic model for a variable speed wind farm (WF) is introduced in this paper. The individual turbine model for the WF is a two mass model and assumed to be operating under maximum power point tracking control strategy. This paper studies pitch based deloading of WF and a control scheme to emulate inertia and support primary frequency control using a dynamic linearized model. The model is linearized between the wind velocity and system frequency vs power output of farm. The model is validated against an actual nonlinear DFIG based WF simulated in Dig-SILENT Power Factory with efficient simulation performance indices. The main advantage of this reduced order model is its capability to predict dynamic frequency response and thus allows frequency response based control strategy for the WF. The savings in computational efforts are significant, with little loss of accuracy.
{"title":"Reduced order modeling of wind farms for inclusion in large power system simulations for primary frequency response application","authors":"Sudipta Ghosh, N. Senroy, S. Kamalasadan","doi":"10.1109/NAPS.2014.6965474","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965474","url":null,"abstract":"A reduced order linearized dynamic model for a variable speed wind farm (WF) is introduced in this paper. The individual turbine model for the WF is a two mass model and assumed to be operating under maximum power point tracking control strategy. This paper studies pitch based deloading of WF and a control scheme to emulate inertia and support primary frequency control using a dynamic linearized model. The model is linearized between the wind velocity and system frequency vs power output of farm. The model is validated against an actual nonlinear DFIG based WF simulated in Dig-SILENT Power Factory with efficient simulation performance indices. The main advantage of this reduced order model is its capability to predict dynamic frequency response and thus allows frequency response based control strategy for the WF. The savings in computational efforts are significant, with little loss of accuracy.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129617384","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965359
Omar A. Urquidez, Le Xie
In this paper, we propose a rectangular representation of FACTS devices such as the Phase Shift Transformer (PST) and the Unified Power Flow Controller (UPFC) in AC optimal power flow problems. This is motivated by the increasing need to incorporate FACTS devices in real-time operations to provide economic and technical benefits to the system. As a first step towards utilizing new control capabilities enabled by devices such as voltage source converters, we propose a rectangular representation of these devices in the AC optimal power flow problem. The rectangular representation of ACOPF has received increasing attraction due to faster convergence compared with conventional polar representation. In this paper, voltage actor FACTS devices such as PST and UPFC are modeled and incorporated in the rectangular ACOPF. The efficacy of the proposed formulation is shown via numerical examples on the IEEE 14 bus system.
{"title":"Rectangular representation of FACTS devices in the ACOPF problem","authors":"Omar A. Urquidez, Le Xie","doi":"10.1109/NAPS.2014.6965359","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965359","url":null,"abstract":"In this paper, we propose a rectangular representation of FACTS devices such as the Phase Shift Transformer (PST) and the Unified Power Flow Controller (UPFC) in AC optimal power flow problems. This is motivated by the increasing need to incorporate FACTS devices in real-time operations to provide economic and technical benefits to the system. As a first step towards utilizing new control capabilities enabled by devices such as voltage source converters, we propose a rectangular representation of these devices in the AC optimal power flow problem. The rectangular representation of ACOPF has received increasing attraction due to faster convergence compared with conventional polar representation. In this paper, voltage actor FACTS devices such as PST and UPFC are modeled and incorporated in the rectangular ACOPF. The efficacy of the proposed formulation is shown via numerical examples on the IEEE 14 bus system.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"396 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116525283","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965439
H. Khazdozian, R. Hadimani, D. Jiles
Permanent magnet generators' (PMGs) dimensions scale with rated power due the sizing law for PMGs, which necessitates increased rotor volume to provide additional torque, preventing use of PMGs in large scale wind turbines. The use of higher energy density permanent magnets may offset the need to scale dimensions to achieve higher input torque. The properties of a permanent magnet necessary to achieve 25% reduction in dimensions in a 10MW wind turbine were calculated. A 29% increase in torque as a result of a 34% increase in the energy product of the permanent magnet is demonstrated.
{"title":"Size reduction of permanent magnet generators for wind turbines with higher energy density permanent magnets","authors":"H. Khazdozian, R. Hadimani, D. Jiles","doi":"10.1109/NAPS.2014.6965439","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965439","url":null,"abstract":"Permanent magnet generators' (PMGs) dimensions scale with rated power due the sizing law for PMGs, which necessitates increased rotor volume to provide additional torque, preventing use of PMGs in large scale wind turbines. The use of higher energy density permanent magnets may offset the need to scale dimensions to achieve higher input torque. The properties of a permanent magnet necessary to achieve 25% reduction in dimensions in a 10MW wind turbine were calculated. A 29% increase in torque as a result of a 34% increase in the energy product of the permanent magnet is demonstrated.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114692554","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965468
Guodong Liu, Yan Xu, O. Ceylan, K. Tomsovic
With increasing penetration of distributed generation in the distribution networks (DN), the secure and optimal operation of DN has become an important concern. As DN control and operation strategies are mostly based on the linearized sensitivity coefficients between controlled variables (e.g., node voltages, line currents, power loss) and control variables (e.g., power injections, transformer tap positions), efficient and precise calculation of these sensitivity coefficients, i.e. linearization of DN, is of fundamental importance. In this paper, the derivation of the node voltages and power loss as functions of the nodal power injections and transformers' tap-changers positions is presented, and then solved by a Gauss-Seidel method. Compared to other approaches presented in the literature, the proposed method takes into account different load characteristics (e.g., constant PQ, constant impedance, constant current and any combination of above) of a generic multi-phase unbalanced DN and improves the accuracy of linearization. Numerical simulations on both IEEE 13 and 34 nodes test feeders show the efficiency and accuracy of the proposed method.
{"title":"A new linearization method of unbalanced electrical distribution networks","authors":"Guodong Liu, Yan Xu, O. Ceylan, K. Tomsovic","doi":"10.1109/NAPS.2014.6965468","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965468","url":null,"abstract":"With increasing penetration of distributed generation in the distribution networks (DN), the secure and optimal operation of DN has become an important concern. As DN control and operation strategies are mostly based on the linearized sensitivity coefficients between controlled variables (e.g., node voltages, line currents, power loss) and control variables (e.g., power injections, transformer tap positions), efficient and precise calculation of these sensitivity coefficients, i.e. linearization of DN, is of fundamental importance. In this paper, the derivation of the node voltages and power loss as functions of the nodal power injections and transformers' tap-changers positions is presented, and then solved by a Gauss-Seidel method. Compared to other approaches presented in the literature, the proposed method takes into account different load characteristics (e.g., constant PQ, constant impedance, constant current and any combination of above) of a generic multi-phase unbalanced DN and improves the accuracy of linearization. Numerical simulations on both IEEE 13 and 34 nodes test feeders show the efficiency and accuracy of the proposed method.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132278404","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965419
D. Geiger, S. Halpin
Renewable energy sources continue to grow in North America and around the world. There is a push to install these renewable energy sources at the low voltage (LV) distribution level to create a distributed generation (DG) power system. Traditionally, the power system is assumed to have one source that is connected to loads through an impedance. Present electromagnetic compatibility (EMC) standardization for both IEC and IEEE is based on this assumption. It is important and necessary to consider how the present standards apply to DG units so that future standardization can account for the shift from one “large” source to multiple “small” distributed sources.
{"title":"Smart grid implications for power quality standardization","authors":"D. Geiger, S. Halpin","doi":"10.1109/NAPS.2014.6965419","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965419","url":null,"abstract":"Renewable energy sources continue to grow in North America and around the world. There is a push to install these renewable energy sources at the low voltage (LV) distribution level to create a distributed generation (DG) power system. Traditionally, the power system is assumed to have one source that is connected to loads through an impedance. Present electromagnetic compatibility (EMC) standardization for both IEC and IEEE is based on this assumption. It is important and necessary to consider how the present standards apply to DG units so that future standardization can account for the shift from one “large” source to multiple “small” distributed sources.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133930558","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965441
M. Benidris, J. Mitra
This work investigates the effects of voltage and reactive power constraints on composite system reliability indices. Four indices have been used to assess contributions of voltage and reactive power constraints in the reliability indices. Extensive simulations on the IEEE Reliability Test System (RTS) based on the AC power flow model were carried out to correlate the violations of these limits and the loading level of the system. A non-linear, AC power flow based model has been used to accurately represent system redispatch. A state space reduction technique has been utilized to reduce the computation time. A comparison between redispatch models using ac and dc power flow has been provided to illustrate the benefits of the more accurate ac flow model and to investigate the effects of the voltage and reactive power constraints on reliability indices.
{"title":"Consideration of the effects of voltage and reactive power constraints on composite system reliability","authors":"M. Benidris, J. Mitra","doi":"10.1109/NAPS.2014.6965441","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965441","url":null,"abstract":"This work investigates the effects of voltage and reactive power constraints on composite system reliability indices. Four indices have been used to assess contributions of voltage and reactive power constraints in the reliability indices. Extensive simulations on the IEEE Reliability Test System (RTS) based on the AC power flow model were carried out to correlate the violations of these limits and the loading level of the system. A non-linear, AC power flow based model has been used to accurately represent system redispatch. A state space reduction technique has been utilized to reduce the computation time. A comparison between redispatch models using ac and dc power flow has been provided to illustrate the benefits of the more accurate ac flow model and to investigate the effects of the voltage and reactive power constraints on reliability indices.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122010287","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965449
Jeremy Lin, M. Hesamzadeh, O. Galland
Nodal pricing is used in electricity markets around the world to facilitate the electricity trading among market participants. The nodal prices are computed by finding the shadow prices of the energy balance and branch constraints in the optimization problem at each node for each market period. The conventional approach to compute the nodal prices is by formulating a security-constrained economic dispatch using DC power flow equations, which ignore the voltage constraints. However, voltage-demand dependence at each electrical node is well studied in the area of voltage stability. In this paper, we first model the voltage constraints using the null space methodology. Then, we derive the voltage-price relationship at each node by deriving two different curves - voltage-demand curve, and price-demand curve - for each node of the system. This information on voltage-price relationship can be useful for better understanding of the economics of voltage support and also for pricing voltage regulation as a novel ancillary service.
{"title":"Application of null space method in computing electricity prices with voltage-stability constraints","authors":"Jeremy Lin, M. Hesamzadeh, O. Galland","doi":"10.1109/NAPS.2014.6965449","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965449","url":null,"abstract":"Nodal pricing is used in electricity markets around the world to facilitate the electricity trading among market participants. The nodal prices are computed by finding the shadow prices of the energy balance and branch constraints in the optimization problem at each node for each market period. The conventional approach to compute the nodal prices is by formulating a security-constrained economic dispatch using DC power flow equations, which ignore the voltage constraints. However, voltage-demand dependence at each electrical node is well studied in the area of voltage stability. In this paper, we first model the voltage constraints using the null space methodology. Then, we derive the voltage-price relationship at each node by deriving two different curves - voltage-demand curve, and price-demand curve - for each node of the system. This information on voltage-price relationship can be useful for better understanding of the economics of voltage support and also for pricing voltage regulation as a novel ancillary service.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123462194","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965483
Mojtaba Sepehry, Mohammad Heidari-Kapourchali, Avinash Banajiger, V. Aravinthan
This paper proposes a new algorithm for reliability evaluation of complex radial distribution networks. The proposed algorithm is based on failure mode and effect analysis (FMEA) method. The paper talks about the definition of network topology using a matrix which is modified and new matrices are derived. These matrices are used for evaluation of load point reliability indices. The rows and columns of these matrices correspond to branches and buses of the network respectively. Each element of these matrices attest a specific relation between a faulted branch and the network bus. The above mentioned salient features make the whole algorithm straight forward to implement in a real distribution system. Thus, the results obtained from this method are verified with the Bus 2 of RBTS.
{"title":"A new algorithm for reliability evaluation of radial distribution networks","authors":"Mojtaba Sepehry, Mohammad Heidari-Kapourchali, Avinash Banajiger, V. Aravinthan","doi":"10.1109/NAPS.2014.6965483","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965483","url":null,"abstract":"This paper proposes a new algorithm for reliability evaluation of complex radial distribution networks. The proposed algorithm is based on failure mode and effect analysis (FMEA) method. The paper talks about the definition of network topology using a matrix which is modified and new matrices are derived. These matrices are used for evaluation of load point reliability indices. The rows and columns of these matrices correspond to branches and buses of the network respectively. Each element of these matrices attest a specific relation between a faulted branch and the network bus. The above mentioned salient features make the whole algorithm straight forward to implement in a real distribution system. Thus, the results obtained from this method are verified with the Bus 2 of RBTS.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128992922","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 : 2014-11-24DOI: 10.1109/NAPS.2014.6965365
J. R. Zuluaga, J. L. Naredo
This work illustrates a network equivalent multirate model based on Discrete Wavelet Transform (DWT) and Multi-Rate analysis (MRA). The processing structure operates as a multi-rate digital filter, decomposing signals and network into frequency sub-bands. This concept is applied in the time domain and adjusts the integration step during the simulation, it is implemented using signal processing theory, and filter banks and the network equivalents is a generalization of the Electro Magnetic Transient Program (EMTP) approach with three different integration rules. Finally two implementations of the proposed model are explained, the first tool is used for parallel processing but with loss of accuracy and the second model is based on the solution of linear systems in state space via Lyapunov equation.
{"title":"Wavelet and multi-rate analysis for the simulation of electromagnetic transients in power systems","authors":"J. R. Zuluaga, J. L. Naredo","doi":"10.1109/NAPS.2014.6965365","DOIUrl":"https://doi.org/10.1109/NAPS.2014.6965365","url":null,"abstract":"This work illustrates a network equivalent multirate model based on Discrete Wavelet Transform (DWT) and Multi-Rate analysis (MRA). The processing structure operates as a multi-rate digital filter, decomposing signals and network into frequency sub-bands. This concept is applied in the time domain and adjusts the integration step during the simulation, it is implemented using signal processing theory, and filter banks and the network equivalents is a generalization of the Electro Magnetic Transient Program (EMTP) approach with three different integration rules. Finally two implementations of the proposed model are explained, the first tool is used for parallel processing but with loss of accuracy and the second model is based on the solution of linear systems in state space via Lyapunov equation.","PeriodicalId":421766,"journal":{"name":"2014 North American Power Symposium (NAPS)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127623658","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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