Pub Date : 2005-12-19DOI: 10.1109/NAPS.2005.1560496
H. Lev-Ari, A. Stanković
The paper considers optimized compensation of loads in unbalanced polyphase networks under non-sinusoidal operation and with significant source impedance. After formulating the problem in a suitable Hilbert space terminology, the optimal solution is obtained using Lagrange multiplier method. The paper also proposes a general framework for obtaining simplified, reduced-order versions of the optimal compensator which depend on fewer parameters, making them easier to implement.
{"title":"Optimization of power flows in polyphase systems with significant source impedance","authors":"H. Lev-Ari, A. Stanković","doi":"10.1109/NAPS.2005.1560496","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560496","url":null,"abstract":"The paper considers optimized compensation of loads in unbalanced polyphase networks under non-sinusoidal operation and with significant source impedance. After formulating the problem in a suitable Hilbert space terminology, the optimal solution is obtained using Lagrange multiplier method. The paper also proposes a general framework for obtaining simplified, reduced-order versions of the optimal compensator which depend on fewer parameters, making them easier to implement.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123230155","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560595
C. Ramos-Robles, A. Irizarry-Rivera
In this paper we analyze wind measurements using the Weibull probability density function (PDF). We estimate the shape factor (k) and the scale factor (c) of a Weibull PDF using maximum likelihood estimators (MLE) and the least squares estimation (LSE) method. We then compare the energy production results that would be obtained when using the parameters estimated with each method. An economical analysis is performed to show the effects of overestimating or underestimating energy production caused by an erroneous estimation of the Weibull PDF parameters. Finally a Monte Carlo simulation is performed to asses the economical risk that the shape and scale parameters represent to the outcome of the project.
{"title":"Economical effects of the Weibull parameter estimation on wind energy projects","authors":"C. Ramos-Robles, A. Irizarry-Rivera","doi":"10.1109/NAPS.2005.1560595","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560595","url":null,"abstract":"In this paper we analyze wind measurements using the Weibull probability density function (PDF). We estimate the shape factor (k) and the scale factor (c) of a Weibull PDF using maximum likelihood estimators (MLE) and the least squares estimation (LSE) method. We then compare the energy production results that would be obtained when using the parameters estimated with each method. An economical analysis is performed to show the effects of overestimating or underestimating energy production caused by an erroneous estimation of the Weibull PDF parameters. Finally a Monte Carlo simulation is performed to asses the economical risk that the shape and scale parameters represent to the outcome of the project.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120952194","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560525
Hui-jie Zheng, Bei Guo
This paper presents a new algorithm to decide the on/off schedule in unit commitment by using the Lagrangian relaxation method. Theoretical analysis of the presented algorithm is provided. A simple search scheme, which avoids the forward searching and back tracing used by dynamic programming (DP) algorithm, is developed. Theoretical analysis and numerical test results show that the presented algorithm can be the substitute of the existing DP algorithm.
{"title":"A new algorithm for unit commitment based on on/off decision criterion","authors":"Hui-jie Zheng, Bei Guo","doi":"10.1109/NAPS.2005.1560525","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560525","url":null,"abstract":"This paper presents a new algorithm to decide the on/off schedule in unit commitment by using the Lagrangian relaxation method. Theoretical analysis of the presented algorithm is provided. A simple search scheme, which avoids the forward searching and back tracing used by dynamic programming (DP) algorithm, is developed. Theoretical analysis and numerical test results show that the presented algorithm can be the substitute of the existing DP algorithm.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120984879","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560568
Fang Yang, A. Meliopoulos, G. Stefopoulos
Locational marginal pricing (LMP) has been deployed by several wholesale markets in United States. Standard market design (SMD) proposed by FERC has also adopted LMP as the foundation for the open market power industry, LMP values are influenced by system operating conditions. If system is unconstrained, LMP values are flat throughout the network. When system is constrained, because of congestion or abnormal voltages, LMP values differentiate at various locations. Their values reflect the increased cost to deliver energy from marginal units to load buses. For speed and simplicity, most LMP models include merely constraints of transmission congestion and consider the generator unit real power output rescheduling as the only way to alleviate transmission congestion. However, in typical power systems there are other types of remedial actions (RAs) that can be applied to alleviate or eliminate system constraints. These RAs include shunt capacitor/reactor switching, transformer tap/phase shifter adjustment, etc. Remedial actions can affect LMPs by virtue of their effect on system active constraints. In this paper, we examine the effectiveness of remedial actions in smoothing LMP values. We propose an LMP computational models that includes RA effects as well as congestion and voltage constraints. The formulation of the problem is based on the single phase quadratized AC power flow model. The problem is linearized using the efficient co-state method leading to a standard linear program which is solved with standard techniques. An example power system is used to demonstrate the proposed framework. LMP values with and without RAs are computed and compared. Results show that effect of RAs on LMP is noteworthy and appropriate RAs can effectively flatten LMP values.
{"title":"Effects of remedial actions on LMPs","authors":"Fang Yang, A. Meliopoulos, G. Stefopoulos","doi":"10.1109/NAPS.2005.1560568","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560568","url":null,"abstract":"Locational marginal pricing (LMP) has been deployed by several wholesale markets in United States. Standard market design (SMD) proposed by FERC has also adopted LMP as the foundation for the open market power industry, LMP values are influenced by system operating conditions. If system is unconstrained, LMP values are flat throughout the network. When system is constrained, because of congestion or abnormal voltages, LMP values differentiate at various locations. Their values reflect the increased cost to deliver energy from marginal units to load buses. For speed and simplicity, most LMP models include merely constraints of transmission congestion and consider the generator unit real power output rescheduling as the only way to alleviate transmission congestion. However, in typical power systems there are other types of remedial actions (RAs) that can be applied to alleviate or eliminate system constraints. These RAs include shunt capacitor/reactor switching, transformer tap/phase shifter adjustment, etc. Remedial actions can affect LMPs by virtue of their effect on system active constraints. In this paper, we examine the effectiveness of remedial actions in smoothing LMP values. We propose an LMP computational models that includes RA effects as well as congestion and voltage constraints. The formulation of the problem is based on the single phase quadratized AC power flow model. The problem is linearized using the efficient co-state method leading to a standard linear program which is solved with standard techniques. An example power system is used to demonstrate the proposed framework. LMP values with and without RAs are computed and compared. Results show that effect of RAs on LMP is noteworthy and appropriate RAs can effectively flatten LMP values.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129704760","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560560
A. Nassif, E. Nino, W. Xu
Flicker can be defined as the impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time. The flicker source detection is an important step in the power quality evaluation process as only after the information about the disturbance location is available, the diagnosis and troubleshooting can be accordingly carried out. This paper is concerned about the flicker source detection subject. The problem is described, the method is proposed and shown to be comprehensive enough to diagnose stationary and random flicker. Analytical proof, a simulation and a practical case assembled in laboratory are presented to show the validity of the method. Its principle is based in the relationship between voltage and current rms values, and it is possible to show that the behavior of this relationship permits one to draw conclusions about the flicker source.
{"title":"A V-I slope-based method for flicker source detection","authors":"A. Nassif, E. Nino, W. Xu","doi":"10.1109/NAPS.2005.1560560","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560560","url":null,"abstract":"Flicker can be defined as the impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time. The flicker source detection is an important step in the power quality evaluation process as only after the information about the disturbance location is available, the diagnosis and troubleshooting can be accordingly carried out. This paper is concerned about the flicker source detection subject. The problem is described, the method is proposed and shown to be comprehensive enough to diagnose stationary and random flicker. Analytical proof, a simulation and a practical case assembled in laboratory are presented to show the validity of the method. Its principle is based in the relationship between voltage and current rms values, and it is possible to show that the behavior of this relationship permits one to draw conclusions about the flicker source.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116209903","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560574
P. Ruiz
The restructuring of the power industry has the objective of increasing the industry's efficiency. The increases in efficiency sometimes have not been realized to the extent possible due to the opposition of some stakeholders to the merger of electricity markets. A clear example is the failed attempt to merge the PJM, NYISO and ISO-NE markets in 2001-2002. In this paper, we propose and investigate a benefit allocation scheme based on cooperative game theory that allows each player to benefit from the merger. The scheme is a temporary solution useful in the transition from the separate markets to the merged market. An illustrative example is provided.
{"title":"Benefit allocation after the merger of electricity markets","authors":"P. Ruiz","doi":"10.1109/NAPS.2005.1560574","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560574","url":null,"abstract":"The restructuring of the power industry has the objective of increasing the industry's efficiency. The increases in efficiency sometimes have not been realized to the extent possible due to the opposition of some stakeholders to the merger of electricity markets. A clear example is the failed attempt to merge the PJM, NYISO and ISO-NE markets in 2001-2002. In this paper, we propose and investigate a benefit allocation scheme based on cooperative game theory that allows each player to benefit from the merger. The scheme is a temporary solution useful in the transition from the separate markets to the merged market. An illustrative example is provided.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132794921","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560499
Nan Zhang, Hongbiao Song, M. Kezunovic
This paper presents a new approach for preventing cascading outage by coordinated system and local monitoring and control scheme. System monitoring evaluates the vulnerability and security of the power system during dynamic changing conditions. It finds the vulnerable power system components indicating that their protective relays need to be monitored closely. Local monitoring can provide the exact disturbance information and monitor the correctness of the actual relay operations. If the relays act improperly, the proposed approach enables one to mitigate the disturbance or prevent the possible cascading outage. Further system control actions may be chosen based on the local information update. Several examples using the IEEE test system demonstrate the advantages of this approach.
{"title":"New monitoring and control scheme for preventing cascading outage","authors":"Nan Zhang, Hongbiao Song, M. Kezunovic","doi":"10.1109/NAPS.2005.1560499","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560499","url":null,"abstract":"This paper presents a new approach for preventing cascading outage by coordinated system and local monitoring and control scheme. System monitoring evaluates the vulnerability and security of the power system during dynamic changing conditions. It finds the vulnerable power system components indicating that their protective relays need to be monitored closely. Local monitoring can provide the exact disturbance information and monitor the correctness of the actual relay operations. If the relays act improperly, the proposed approach enables one to mitigate the disturbance or prevent the possible cascading outage. Further system control actions may be chosen based on the local information update. Several examples using the IEEE test system demonstrate the advantages of this approach.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121956427","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560566
W. Siever, R. Kalyani, M. Crow, D. Tauritz
Increasing demand coupled with limitations on new construction indicate that existing power transmission must be better controlled in order to continue reliable operation. Recent advances in FACTS devices provide a mechanism to better control power flow on the transmission network. One particular device, the unified power flow controller (UPFC), holds the most promise for maintaining operation even when the system has suffered partial failure (either naturally occurring, due to human error, or a malicious attack). In addition to the capital cost, the primary obstacles to widespread UPFC use are the combined problems of selecting the most cost effective locations for installation and maintaining proper control of them once installed. In this paper we list evidence that gradient descent search based on load-flow computation is more realistic and accurate than many of the optimization techniques currently in use. We then demonstrate that gradient descent search can be used to select control points that improve system fault tolerance more than those found by the max-flow technique. In addition, we demonstrate that the size of the system being computed and the number of computations is bounded and is practical for real time control.
{"title":"UPFC control employing gradient descent search","authors":"W. Siever, R. Kalyani, M. Crow, D. Tauritz","doi":"10.1109/NAPS.2005.1560566","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560566","url":null,"abstract":"Increasing demand coupled with limitations on new construction indicate that existing power transmission must be better controlled in order to continue reliable operation. Recent advances in FACTS devices provide a mechanism to better control power flow on the transmission network. One particular device, the unified power flow controller (UPFC), holds the most promise for maintaining operation even when the system has suffered partial failure (either naturally occurring, due to human error, or a malicious attack). In addition to the capital cost, the primary obstacles to widespread UPFC use are the combined problems of selecting the most cost effective locations for installation and maintaining proper control of them once installed. In this paper we list evidence that gradient descent search based on load-flow computation is more realistic and accurate than many of the optimization techniques currently in use. We then demonstrate that gradient descent search can be used to select control points that improve system fault tolerance more than those found by the max-flow technique. In addition, we demonstrate that the size of the system being computed and the number of computations is bounded and is practical for real time control.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128694932","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560511
P.E. Onate, J. M. Ramirez
This paper is aimed to the solution of the short-term-hydrothermal generation scheduling problem (HGSP) by means of a genetic algorithm. The hydrothermal coordination is solved using an equivalent cost function for the available thermal units, while the unit commitment and the economic dispatch are solved considering the more capable individuals that are obtained from the hydrothermal coordination stage, restrictions of volume and discharges of water are dealt with, generating limits of both hydroelectric and thermal units, physical limitations on the storage volumes of reservoirs as well as discharged quantities. The spinning reserve and losses are considered too.
{"title":"Optimal operation of hydrothermal systems in the short term","authors":"P.E. Onate, J. M. Ramirez","doi":"10.1109/NAPS.2005.1560511","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560511","url":null,"abstract":"This paper is aimed to the solution of the short-term-hydrothermal generation scheduling problem (HGSP) by means of a genetic algorithm. The hydrothermal coordination is solved using an equivalent cost function for the available thermal units, while the unit commitment and the economic dispatch are solved considering the more capable individuals that are obtained from the hydrothermal coordination stage, restrictions of volume and discharges of water are dealt with, generating limits of both hydroelectric and thermal units, physical limitations on the storage volumes of reservoirs as well as discharged quantities. The spinning reserve and losses are considered too.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124971908","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 : 2005-12-19DOI: 10.1109/NAPS.2005.1560497
J. Momoh, G. Boswell
Distributed generation (DG) has emerged as a practical and viable technology for alleviating power system shortages related to generation and transmission inadequacies. The market location and coordination of a selected DG technology is of high importance to engineers and power marketers. This paper develops an approach for coordinating DG on a grid/micro-grid and solves the resource allocation problem in the framework of a voltage stability constrained optimal power flow. Continuation power flow (CPF) was used to determine weak voltage nodes that are vulnerable to voltage collapse as well as determination of the voltage stability margin (VSM). The impact assessment of DG is computed in terms of the added value to the locational marginal price (LMP) differentials between neighboring network nodes as well as across area boundaries. LMP was used to compute the market implications of installing DG sources. The value of DG (or its detrimental impacts) is monitored and the corresponding available transfer capabilities (ATC) of critical interfaces were determined. The feasibility of the developed approach for value-based DG implementation was tested on a 30-bus 330 kV high voltage system model.
{"title":"Value-based implementation of distributed generation in optimal power flow","authors":"J. Momoh, G. Boswell","doi":"10.1109/NAPS.2005.1560497","DOIUrl":"https://doi.org/10.1109/NAPS.2005.1560497","url":null,"abstract":"Distributed generation (DG) has emerged as a practical and viable technology for alleviating power system shortages related to generation and transmission inadequacies. The market location and coordination of a selected DG technology is of high importance to engineers and power marketers. This paper develops an approach for coordinating DG on a grid/micro-grid and solves the resource allocation problem in the framework of a voltage stability constrained optimal power flow. Continuation power flow (CPF) was used to determine weak voltage nodes that are vulnerable to voltage collapse as well as determination of the voltage stability margin (VSM). The impact assessment of DG is computed in terms of the added value to the locational marginal price (LMP) differentials between neighboring network nodes as well as across area boundaries. LMP was used to compute the market implications of installing DG sources. The value of DG (or its detrimental impacts) is monitored and the corresponding available transfer capabilities (ATC) of critical interfaces were determined. The feasibility of the developed approach for value-based DG implementation was tested on a 30-bus 330 kV high voltage system model.","PeriodicalId":101495,"journal":{"name":"Proceedings of the 37th Annual North American Power Symposium, 2005.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127862604","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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