EPE Association: NORpie 2008 - Topic 01: WIND POWER

NORpie 2008 - Topic 01: WIND POWER
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2008 > NORpie 2008 - Topic 01: WIND POWER

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   Variable speed pumped storage hydropower for integration of wind energy in isolated grids - case description and control strategies
By Jon Are Suul, Kjetil Uhlen, Tore Undeland [View]
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Abstract: This paper presents the use of variable speed pumped storage hydropower plants for balancing power fluctuations from wind power in an isolated grid. A topology based on a synchronous machine and a full scale back-to-back voltage source converter is suggested for obtaining variable speed operation of a pump-turbine unit. This topology has not been previously investigated for variable speed pumped storage power plants, but can now be considered relevant for small and medium sized pumped storage units because of the development of voltage source converter drives for higher voltage levels. A possible case for implementation of such a system is described based on the situation on the Faroe Islands, where controllable energy storage can help to allow for a higher share of renewable energy in the power system and by that to reduce the dependency on fossil fuels. Power control of the pumped storage unit by load following for direct compensation of the fluctuations in power output from a wind farm will limit the influence on the operation of the rest of the grid. By utilizing the pumped storage to take part in the primary frequency control of the power system, the frequency response to other changes in production or load will also be improved.

   Power Collection and Integration on the Electric Grid from Offshore Wind Parks
By Anne Berit Mogstad, Marta Molinas [View]
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Abstract: There is a lot of potential in offshore wind parks due to the amount of available area. The parks get bigger in size and will continue to grow in the future. In this article a new converter topology for offshore wind parks is proposed. This topology is meant to be for large offshore wind parks sited far from shore and it is based on DC collection and transmission. All the converters are located in the nacelle of the wind turbines and the turbines are connected in series directly connected to shore without any transformation stages. The electrical system, from the generator to the grid connection of the turbine, is modeled in PSCAD. The model consists of an induction machine, a 3-phase AC to 1-phase AC converter, a high frequency high power transformer and a full-bridge converter. The AC-AC converter has a new type of reverse-blocking IGBTs and the switches are controlled with a dedicated switching pattern. The simulations show that the switching pattern gives the expected square wave voltage from the AC-AC converter. The new converter topology reduces the converter losses due to fewer converter stages, the architecture of the reverse-blocking IGBT and the new switching pattern.

NORpie 2008 - Topic 01: WIND POWER
You are here: EPE Documents > 05 - EPE Supported Conference Proceedings > NORpie - Proceedings > NORpie 2008 > NORpie 2008 - Topic 01: WIND POWER
	[return to parent folder]

	Variable speed pumped storage hydropower for integration of wind energy in isolated grids - case description and control strategies By Jon Are Suul, Kjetil Uhlen, Tore Undeland	[View] [Download]
Abstract: This paper presents the use of variable speed pumped storage hydropower plants for balancing power fluctuations from wind power in an isolated grid. A topology based on a synchronous machine and a full scale back-to-back voltage source converter is suggested for obtaining variable speed operation of a pump-turbine unit. This topology has not been previously investigated for variable speed pumped storage power plants, but can now be considered relevant for small and medium sized pumped storage units because of the development of voltage source converter drives for higher voltage levels. A possible case for implementation of such a system is described based on the situation on the Faroe Islands, where controllable energy storage can help to allow for a higher share of renewable energy in the power system and by that to reduce the dependency on fossil fuels. Power control of the pumped storage unit by load following for direct compensation of the fluctuations in power output from a wind farm will limit the influence on the operation of the rest of the grid. By utilizing the pumped storage to take part in the primary frequency control of the power system, the frequency response to other changes in production or load will also be improved.

	Power Collection and Integration on the Electric Grid from Offshore Wind Parks By Anne Berit Mogstad, Marta Molinas	[View] [Download]
Abstract: There is a lot of potential in offshore wind parks due to the amount of available area. The parks get bigger in size and will continue to grow in the future. In this article a new converter topology for offshore wind parks is proposed. This topology is meant to be for large offshore wind parks sited far from shore and it is based on DC collection and transmission. All the converters are located in the nacelle of the wind turbines and the turbines are connected in series directly connected to shore without any transformation stages. The electrical system, from the generator to the grid connection of the turbine, is modeled in PSCAD. The model consists of an induction machine, a 3-phase AC to 1-phase AC converter, a high frequency high power transformer and a full-bridge converter. The AC-AC converter has a new type of reverse-blocking IGBTs and the switches are controlled with a dedicated switching pattern. The simulations show that the switching pattern gives the expected square wave voltage from the AC-AC converter. The new converter topology reduces the converter losses due to fewer converter stages, the architecture of the reverse-blocking IGBT and the new switching pattern.