Pub Date : 2008-12-16DOI: 10.1109/UPEC.2008.4651458
Youbing Zhang, Wei Chen, Q. Gao, Zhijian Liu, Yijia Cao
Interruptible load (IL) management as an important component of demand-side management in electricity market affects much the safe and economic operation of the power systems. The cost-benefit of interruptible load participants is analyzed in this paper. The discrete customer category is proposed to indicate the expected compensation for the blackout. This paper presents a model of IL contract, in which the objective function is the minimum compensation cost paid by the power company. The benefits of the power company and the customer are both considered as the restrictions of the model. The actual system examples show the validity of the proposed model.
{"title":"Model of interruptible load contract for minimum compensation cost","authors":"Youbing Zhang, Wei Chen, Q. Gao, Zhijian Liu, Yijia Cao","doi":"10.1109/UPEC.2008.4651458","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651458","url":null,"abstract":"Interruptible load (IL) management as an important component of demand-side management in electricity market affects much the safe and economic operation of the power systems. The cost-benefit of interruptible load participants is analyzed in this paper. The discrete customer category is proposed to indicate the expected compensation for the blackout. This paper presents a model of IL contract, in which the objective function is the minimum compensation cost paid by the power company. The benefits of the power company and the customer are both considered as the restrictions of the model. The actual system examples show the validity of the proposed model.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115228617","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651593
L. Carradore, F. Bignucolo
The recent growth of energy consumptions concerns not only electrical demand. In this perspective, the synergy between different energy vectors seems to have a key role for the future. In this paper distributed multi-generation in multi-vector networks with energy hubs and the advantages of this system for improving the management of loads and generators in the electric network are analysed. In particular, an optimization procedure based on energy market interactions is discussed.
{"title":"Distributed multi-generation and application of the energy hub concept in future networks","authors":"L. Carradore, F. Bignucolo","doi":"10.1109/UPEC.2008.4651593","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651593","url":null,"abstract":"The recent growth of energy consumptions concerns not only electrical demand. In this perspective, the synergy between different energy vectors seems to have a key role for the future. In this paper distributed multi-generation in multi-vector networks with energy hubs and the advantages of this system for improving the management of loads and generators in the electric network are analysed. In particular, an optimization procedure based on energy market interactions is discussed.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115648604","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651612
M. Savaghebi, A. Gholami, A. Jalilian
The portion of the loads which cause harmonic currents is increasing due to the rising prevalence of power electronic components. The use of these loads has increased the awareness of the potential risks due to the transformer overheating. Nowadays, it is well-known that the transformer loading must be restricted for safe operation under non-linear load currents. Conventionally, IEEE C57.110-1998 standard has been applied to give a conservative estimate of loading capability of transformer in this condition. In this paper, the problem of oil-immersed transformer loading capability determination considering nonlinear loads is addressed. A thermal model which considers non-sinusoidal load current is used. Then, the procedure of transformer dynamic and steady state loading capability assessment is described and applied to a power transformer. Comparison of the results of the proposed and conventional methods shows the possibility of transformer loading beyond the limit calculated using conventional method. Finally, an economic analysis is carried out considering two methods.
{"title":"Transformer dynamic loading capability assessment under nonlinear load currents","authors":"M. Savaghebi, A. Gholami, A. Jalilian","doi":"10.1109/UPEC.2008.4651612","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651612","url":null,"abstract":"The portion of the loads which cause harmonic currents is increasing due to the rising prevalence of power electronic components. The use of these loads has increased the awareness of the potential risks due to the transformer overheating. Nowadays, it is well-known that the transformer loading must be restricted for safe operation under non-linear load currents. Conventionally, IEEE C57.110-1998 standard has been applied to give a conservative estimate of loading capability of transformer in this condition. In this paper, the problem of oil-immersed transformer loading capability determination considering nonlinear loads is addressed. A thermal model which considers non-sinusoidal load current is used. Then, the procedure of transformer dynamic and steady state loading capability assessment is described and applied to a power transformer. Comparison of the results of the proposed and conventional methods shows the possibility of transformer loading beyond the limit calculated using conventional method. Finally, an economic analysis is carried out considering two methods.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117223450","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651508
H. Shateri, S. Jamali
Distance relays are one of the mostly used protective devices in the transmission systems. These relays are used as the main, First zone and a part of second zone, and the backup, the rest of second zone and third zone, protective devices. Fault resistance is a source of error for distance relays in the form of the measured impedance deviation from its actual value. This paper investigates the measured impedance by distance relays for the faults on the protected and next line in the case of inter phase, phase to phase and three phase, faults by means of presenting measured impedance and investigating its variation duo the changes in the power system conditions.
{"title":"Measured impedance at relaying point for inter phase faults on next line","authors":"H. Shateri, S. Jamali","doi":"10.1109/UPEC.2008.4651508","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651508","url":null,"abstract":"Distance relays are one of the mostly used protective devices in the transmission systems. These relays are used as the main, First zone and a part of second zone, and the backup, the rest of second zone and third zone, protective devices. Fault resistance is a source of error for distance relays in the form of the measured impedance deviation from its actual value. This paper investigates the measured impedance by distance relays for the faults on the protected and next line in the case of inter phase, phase to phase and three phase, faults by means of presenting measured impedance and investigating its variation duo the changes in the power system conditions.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121260337","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651626
M. Albano, A. Haddad, H. Griffiths, P. Coventry
With the known greenhouse effect of SF6-insulated substations, the aim now is to reduce the size of transmission substations using air-insulated designs. In this work, a 400 kV compact substation layout is proposed adopting the lower IEC basic insulation level and switching impulse level, and consequently reduced clearances. Simulation studies using EMTP are performed to evaluate the lightning and switching performance of the proposed compact substation using different surge arrester locations and ratings. Further proposals for compaction are investigated through the introduction of innovative high voltage equipments. A preliminary evaluation of the percentage space saving achieved with some of the illustrated compact solutions is presented.
{"title":"Air insulated compact substations","authors":"M. Albano, A. Haddad, H. Griffiths, P. Coventry","doi":"10.1109/UPEC.2008.4651626","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651626","url":null,"abstract":"With the known greenhouse effect of SF6-insulated substations, the aim now is to reduce the size of transmission substations using air-insulated designs. In this work, a 400 kV compact substation layout is proposed adopting the lower IEC basic insulation level and switching impulse level, and consequently reduced clearances. Simulation studies using EMTP are performed to evaluate the lightning and switching performance of the proposed compact substation using different surge arrester locations and ratings. Further proposals for compaction are investigated through the introduction of innovative high voltage equipments. A preliminary evaluation of the percentage space saving achieved with some of the illustrated compact solutions is presented.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124820367","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651435
T. Radošević, K. Vrdoljak, N. Peric
This paper presents the usage of sliding mode control algorithm for load-frequency control in power systems. One of main obstacles in the usage of sliding mode based load-frequency control is the difficulty in choosing optimal controller parameters. In this paper, appropriate sliding mode algorithm parameters are obtained using integral performance criterion. Those parameters ensure stability, accuracy and robustness of load-frequency control system. Obtained parameters are tested on simulations, which are conducted on a power system model consisting of three interconnected control areas.
{"title":"Optimal sliding mode controller for power system’s load-frequency control","authors":"T. Radošević, K. Vrdoljak, N. Peric","doi":"10.1109/UPEC.2008.4651435","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651435","url":null,"abstract":"This paper presents the usage of sliding mode control algorithm for load-frequency control in power systems. One of main obstacles in the usage of sliding mode based load-frequency control is the difficulty in choosing optimal controller parameters. In this paper, appropriate sliding mode algorithm parameters are obtained using integral performance criterion. Those parameters ensure stability, accuracy and robustness of load-frequency control system. Obtained parameters are tested on simulations, which are conducted on a power system model consisting of three interconnected control areas.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124854673","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651541
F. Pilo, G. Pisano, G. G. Soma
A heuristic optimization algorithm based on the Dynamic Programming theory is proposed to find the optimal placement of measurement devices, i.e. to determine their number and position. The optimization procedure explicitly considers network reconfigurations (caused by random faults or by the active management of the network), so that the final measurement system allows the distribution state estimation to provide an accurate estimate of the system status in all the possible practical conditions. The branch currents are taken as state variables for improving the quality of the solution of the state estimator that exploits field measurements and load pseudo-measurements. The uncertainties introduced by the measurement chain are simulated with a Monte Carlo algorithm. Variations of both load demand and network parameters are also modeled in the Monte Carlo algorithm. The provided examples show the effectiveness of the optimization process.
{"title":"Robust distribution state estimation for active networks","authors":"F. Pilo, G. Pisano, G. G. Soma","doi":"10.1109/UPEC.2008.4651541","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651541","url":null,"abstract":"A heuristic optimization algorithm based on the Dynamic Programming theory is proposed to find the optimal placement of measurement devices, i.e. to determine their number and position. The optimization procedure explicitly considers network reconfigurations (caused by random faults or by the active management of the network), so that the final measurement system allows the distribution state estimation to provide an accurate estimate of the system status in all the possible practical conditions. The branch currents are taken as state variables for improving the quality of the solution of the state estimator that exploits field measurements and load pseudo-measurements. The uncertainties introduced by the measurement chain are simulated with a Monte Carlo algorithm. Variations of both load demand and network parameters are also modeled in the Monte Carlo algorithm. The provided examples show the effectiveness of the optimization process.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"682 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116109459","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651683
S. Quaia
Subject of this paper is dynamic coordination of power station controls and protections in All Electric Ships (AESs). The aim is to promote an integrated approach to the design of control systems and protections, which are involved in the overall management of the station and therefore have a relevant impact on power generation, quality and safety. Normally, the design of alternators, AVRs and protections is demanded to different subjects, who often do not share information. This prevents from performing a systematic analysis of transient phenomena and can lead, in critical cases, to a wrong dynamic operation of the system, with possible heavy consequences. This work aims at improving dynamic coordination between AESs power stations protections and controls.
{"title":"All Electric Ship power stations: Dynamic coordination between controls and protections","authors":"S. Quaia","doi":"10.1109/UPEC.2008.4651683","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651683","url":null,"abstract":"Subject of this paper is dynamic coordination of power station controls and protections in All Electric Ships (AESs). The aim is to promote an integrated approach to the design of control systems and protections, which are involved in the overall management of the station and therefore have a relevant impact on power generation, quality and safety. Normally, the design of alternators, AVRs and protections is demanded to different subjects, who often do not share information. This prevents from performing a systematic analysis of transient phenomena and can lead, in critical cases, to a wrong dynamic operation of the system, with possible heavy consequences. This work aims at improving dynamic coordination between AESs power stations protections and controls.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122439496","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651622
R. Bhattarai, R. Rashedin, S. Venkatesan, A. Haddad, H. Griffiths, N. Harid
This paper presents a comparative lightning performance study conducted on a 275 kV double circuit shielded transmission line using two software programs, TFlash and Sigma-Slp. The line performance was investigated by using both a single stroke and a statistical performance analysis and considering cases of shielding failure and backflashover. A sensitivity analysis was carried out to determine the relationship between the flashover rate and the parameters influencing it. To improve the lightning performance of the line, metal oxide surge arresters were introduced using different phase and line locations. Optimised arrester arrangements are proposed.
{"title":"Lightning performance of 275 kV transmission lines","authors":"R. Bhattarai, R. Rashedin, S. Venkatesan, A. Haddad, H. Griffiths, N. Harid","doi":"10.1109/UPEC.2008.4651622","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651622","url":null,"abstract":"This paper presents a comparative lightning performance study conducted on a 275 kV double circuit shielded transmission line using two software programs, TFlash and Sigma-Slp. The line performance was investigated by using both a single stroke and a statistical performance analysis and considering cases of shielding failure and backflashover. A sensitivity analysis was carried out to determine the relationship between the flashover rate and the parameters influencing it. To improve the lightning performance of the line, metal oxide surge arresters were introduced using different phase and line locations. Optimised arrester arrangements are proposed.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116742315","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 : 2008-12-16DOI: 10.1109/UPEC.2008.4651473
O. Samuelsson, L. Lindgren
Outage time after extensive blackouts depends very much on the power system restoration process. Power system restoration is a very challenging task to the operator since the situation is so far from normal conditions. This paper proposes a simulation-based tool that determines a feasible sequence of operator actions that restores power system operation. The effect of each candidate switching operation or setpoint change is evaluated mainly in terms of restored load and the predicted steady state voltage and frequency. Application to the CIGRE NORDIC32 test system shows that operation is fully restored from complete blackout after about 750 actions including network switching and gradual connection of system loads. The main applications of the methodology are off-line use for surveying new restoration strategies and on-line use for suggesting the next action to the operator.
{"title":"Simulated power system restoration","authors":"O. Samuelsson, L. Lindgren","doi":"10.1109/UPEC.2008.4651473","DOIUrl":"https://doi.org/10.1109/UPEC.2008.4651473","url":null,"abstract":"Outage time after extensive blackouts depends very much on the power system restoration process. Power system restoration is a very challenging task to the operator since the situation is so far from normal conditions. This paper proposes a simulation-based tool that determines a feasible sequence of operator actions that restores power system operation. The effect of each candidate switching operation or setpoint change is evaluated mainly in terms of restored load and the predicted steady state voltage and frequency. Application to the CIGRE NORDIC32 test system shows that operation is fully restored from complete blackout after about 750 actions including network switching and gradual connection of system loads. The main applications of the methodology are off-line use for surveying new restoration strategies and on-line use for suggesting the next action to the operator.","PeriodicalId":287461,"journal":{"name":"2008 43rd International Universities Power Engineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129546575","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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