| 1. |
- Besnard, Francois, et al.
(författare)
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An Optimization Framework for Opportunistic Maintenance of Offshore Wind Power System
- 2009
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Ingår i: 2009 IEEE BUCHAREST POWERTECH, VOLS 1-5. - NEW YORK : IEEE. - 9781424422340 ; , s. 2970-2976
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Konferensbidrag (refereegranskat)abstract
- A sound maintenance planning is of crucial importance for wind power farms, and especially for offshore locations. There is a large potential in cost savings by maintenance optimization to make the projects more cost-efficient. This paper presents an opportunistic maintenance optimization model for offshore wind power system. The model takes advantage of wind forecasts and corrective maintenance activities in order to perform preventive maintenance tasks at low costs. The approach is illustrated with an example to demonstrate the value of the optimization. In this example 43% of the cost to perform preventive maintenance could be saved using the proposed method.
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| 2. |
- Bollen, Math, et al.
(författare)
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Controlled island operation of part of the 50-kV grid in Southern Sweden
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech Proceedings. - Piscataway, NJ : : IEEE Communications Society. - 9781424422357 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- This paper is based on measurements obtained during a test of controlled islanding of part of the 50-kV grid in Southern Sweden. The purpose of the test was to verify operation of generator controls during islanding. The variations in voltage magnitude and frequency are shown as well as flicker severity and very-short variations. A number of performance indices have been calculated and compared with limits. Voltage magnitude and frequency have been studied in some detail around the disconnection and reconnection instants. The frequency varies much more during the island operation than during grid-connected operation. Voltage magnitude variations and flicker remain within their normal range. However the variations in the time range between 3 seconds and 10 minute appear to be higher than normal.
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| 3. |
- Chenine, Moustafa, et al.
(författare)
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Survey on Priorities and Communication Requirements for PMU-based Applications in the Nordic Region
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech. - : IEEE. - 9781424422340 ; , s. 1183-1190
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Konferensbidrag (refereegranskat)abstract
- Phasor based Wide Area Monitoring and Control Systems (WAMC) promise to offer more accurate and timely data on the state of the power system, thus, increasing the possibilities to manage the system at a more efficient and responsive level and apply wide area control and protection schemes. This paper presents results of a survey on communications and technical requirements for applications based on Phasor Measurement Units (PMU). The survey was carried out in the Nordic Region with participants from Transmission System Operators (TSOs) and researchers. The survey focused on documenting the stage of research and development among TSOs and researchers in the Nordic Region, as well as, their plans and visions for the future. This includes planned PMU deployments and prioritization of PMU based applications. Furthermore, a significant part of the survey was an elicitation of communication requirements for applications based on PMU data. In the paper, an examination of the time requirements for these applications in terms of delays and samples per second and comparison similar published specifications is provided.
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| 4. |
- König, Johan, et al.
(författare)
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Assessing Impact of ICT System Quality on Operation of Active Distribution Grids
- 2009
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Ingår i: 2009 IEEE BUCHAREST POWERTECH. - NEW YORK : IEEE. - 9781424422340 ; , s. 1977-1984
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Konferensbidrag (refereegranskat)abstract
- This position paper presents starting research on assessment of ICT system characteristics and their impact on controllability and observability of future electricity distribution grids. The aspects of controllability and observability for active grids are key factors for guaranteeing safe, efficient and reliable network operation. An assessment framework is proposed for analyzing the impact of ICT system quality on controllability and observability of the power distribution grid. The proposed assessment method is based on architectural models extended with a probabilistic inference analysis engine. For this, a combination between Enterprise Architecture meta-models and extended influence diagrams are proposed. The paper presents how the framework is constructed and the method on applying it for analysis. The paper is concluded with an example providing an instantiation of the assessment framework.
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| 5. |
- Latorre, Hector F., et al.
(författare)
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Use of Local and Remote Information in POD Control of a VSC-HVdc
- 2009
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Ingår i: 2009 IEEE BUCHAREST POWERTECH. - NEW YORK : IEEE. - 9781424422340 ; , s. 793-798
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Konferensbidrag (refereegranskat)abstract
- VSC-HVdcs have shown to be effective means to increase margins of stability in transmission systems. An appropriate control strategy and a correct selection of input signals allow VSC-HVdcs to enhance transient stability, damp power oscillations and provide voltage support in a significant way. In this paper the use of local and remote information in control strategies for POD in the control of a VSC-HVdc are studied. Two main control strategies are considered one of them based on linear control and the other one based on nonlinear control. As local signals current through transmission lines and frequency at connecting nodes of the VSC-HVdc are used. Rotor angles and speed of the generators are used as remote signals.
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| 6. |
- Lundmark, Martin, et al.
(författare)
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EMC filter common mode resonance
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech. - Piscataway, NJ : IEEE Communications Society. - 9781424422340 ; , s. 2312-2317
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Konferensbidrag (refereegranskat)abstract
- This paper discusses the possibility that high common mode voltages occur in low-voltage distribution due to oscillations between parallel connected EMC-filters. It is shown that such oscillations may occur in the frequency range between 2 kHz to 150 kHz. Simulations and measurements have been carried out with different types of parallel connected power inlet filter, a common EMC Filter, and the circumstances giving oscillations have been highlighted.
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| 7. |
- Nilsson, Julia, et al.
(författare)
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An Opportunistic Maintenance Optimization Model for Shaft Seals in Feed-Water Pump Systems in Nuclear Power Plants
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech. - New York : IEEE. - 9781424422340 ; , s. 2962-2969
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Konferensbidrag (refereegranskat)abstract
- Nuclear power is one of the main electricity production sources in Sweden today. Maintenance management is one tool for reducing the costs for operation of a power plant. Driving forces for cost-efficiency has pushed the development of new methods for maintenance planning and optimization forward. Reliability Centered Asset Management (RCAM) is one of these new approaches, and maintenance optimization is one way to perform quantitative analysis which is a feature of RCAM. This paper proposes a model for opportunistic maintenance optimization where replacement schedules for shaft seals in feed-water pump systems in nuclear power plants are constructed. The feed-water pump system is important for the availability of the entire nuclear power plant. Results show that the optimization model is dependent on e.g. the discount interest and a limit for when the optimal solution goes from non-opportunistic to opportunistic is calculated. The circumstances for which opportunistic maintenance could be used have been investigated given different values of discount rates and remaining life at start of the planning period.
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| 8. |
- Perninge, Magnus, et al.
(författare)
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The Impact of a Given Trading Limit on a Two-Area Test System
- 2009
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Ingår i: 2009 IEEE BUCHAREST POWERTECH. - NEW YORK : IEEE. - 9781424422340 ; , s. 2122-2127
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Konferensbidrag (refereegranskat)abstract
- This paper uses methods from stochastic analysis and stochastic modeling to determine the impact of a certain trading limit on the transfer between the two areas of a benchmark two-area power system. We also try to state which uncertainties are important to consider when calculating this power transfer.
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| 9. |
- Setréus, Johan, et al.
(författare)
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Components' Impact on Critical Transfer Section for Risk Based Transmission System Planning
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech. - : IEEE. - 9781424422340 ; , s. 368-375
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Konferensbidrag (refereegranskat)abstract
- In the planning of the electrical transmission system it is of greatest concern to quantify the security margin for unwanted conditions in the system. This paper proposes an approach based on quantifying the risk of insufficient transmission capacity in bottlenecks in the system. Stresses in these critical transfer sections (CTS) provide a potential risk to corrective actions, or worst, load curtailments. The proposed method provides a general screening of component outages in order to find potential risk events for the CTS. Furthermore, the severity of each risk event is quantified based on the likelihood of the event and the consequence on the section's transmission capacity. The components' contribution to the risk of insufficient capacity in the CTS is then based on these risk events' severity. The method investigates several forecasted load levels during the year and consequently gives an input to a scheme for a risk based transmission system planning. The method is demonstrated on the reliability test system RBTS.
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| 10. |
- Zhang, Lidong, et al.
(författare)
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Multivariable feedback design of VSC-HVDC connected to weak ac systems
- 2009
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Ingår i: 2009 IEEE Bucharest PowerTech. - : IEEE. - 9781424422340 ; , s. 764-771
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Konferensbidrag (refereegranskat)abstract
- Power-synchronization control is particularly applicable to voltage-source converters based high-voltage direct-current (HVDC) transmission connected to weak ac systems. In this paper, the multivariable feedback design aspect of the power-synchronization control is investigated by two design approaches: internal model control (IMC) and Hinfin control. The paper shows that both of the methods can meet the design requirements and show good robustness with different model uncertainties and load disturbances. The advantage of the IMC approach is that it provides a transparent framework for control-system design and tuning. The algorithm used for the IMC design in this paper is simple, yet it achieves similar or even better performance and robustness compared to the more advanced optimization-based Hinfin controller.
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