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CN-114982086-B - Method for operating at least one wind turbine, and wind turbine or group of wind turbines

CN114982086BCN 114982086 BCN114982086 BCN 114982086BCN-114982086-B

Abstract

A method for operating at least one wind turbine (1), which wind turbine (1) is electrically coupled to a power-to-gas converter (4) and to a power grid (3), wherein a control unit (5) determines a power level (20) of power generated by at least one generator (2) of the at least one wind turbine (1), and feeds the generated power to the power-to-gas converter (4) at least partly when the determined power level (20) reaches or exceeds a given lower threshold (15), wherein the amount of power fed to the power-to-gas converter (4) remains constant when the determined power level (20) reaches or exceeds a given upper threshold (17).

Inventors

  • F.D. Madsen
  • H.B. Mortensen
  • P. Skelbeck
  • J. Kiestez
  • J. Thomson

Assignees

  • 西门子歌美飒可再生能源公司

Dates

Publication Date
20260508
Application Date
20210111
Priority Date
20200129

Claims (8)

  1. 1. A method for operating at least one wind turbine (1), the wind turbine (1) being electrically coupled to a power-to-gas converter (4) and a power grid (3), wherein a control unit (5) determines a power level (20) of power generated by at least one generator (2) of the at least one wind turbine (1) and feeds the generated power to the power-to-gas converter (4) at least partly when the determined power level (20) reaches or exceeds a given lower threshold (15), characterized in that the amount of power fed to the power-to-gas converter (4) remains constant when the determined power level (20) reaches or exceeds a given upper threshold (17).
  2. 2. A method according to claim 1, characterized in that when the determined power level (20) reaches or exceeds the upper threshold (17), the power fed to the power-to-gas converter (4) is kept constant by feeding power exceeding the upper threshold (17) to the grid (3).
  3. 3. Method according to claim 1 or 2, characterized in that when the determined power level (20) is between the lower threshold (15) and the upper threshold (17), a constant amount of power is fed to the grid (3) by varying the amount of power fed to the power-to-gas converter (4).
  4. 4. Method according to claim 1 or 2, characterized in that when the determined power level (20) is at or below the lower threshold value (15), all power generated by the at least one generator (2) and not used for the operation of the wind turbine (1) itself is fed to the grid (3).
  5. 5. Method according to claim 1 or 2, characterized in that the upper and/or lower threshold value (15, 17) is determined during production of the wind turbine (1) and/or is dependent on the rated power of the power-to-gas converter (4) and/or is manually adjusted by a user.
  6. 6. Method according to claim 1 or 2, wherein the at least one wind turbine is designed to provide a given maximum power (11), wherein the lower threshold value (15) corresponds to between 30% and 50% of the maximum power (11), and/or wherein the upper threshold value (17) corresponds to 75% to 95% of the maximum power (11).
  7. 7. A method according to claim 1 or 2, wherein an electrolyzer is used as an electrical power to gas converter (4) to generate hydrogen from water.
  8. 8. Wind turbine or group of wind turbines comprising at least one generator (2) electrically coupled to a power-to-gas converter (4) of the wind turbine (1) or group of wind turbines (1) and coupling means (6) for coupling the generator (2) to a power grid (3), wherein during operation of the wind turbine (1) or group of wind turbines (1) the power distribution between the power-to-gas converter (4) and the power grid (3) is determined by a control unit (5), characterized in that the control unit (5) is designed to implement the method according to any of claims 1 to 7.

Description

Method for operating at least one wind turbine, and wind turbine or group of wind turbines The invention relates to a method for operating at least one wind turbine, which is electrically coupled to a power-to-gas converter and to a power grid, wherein a control unit determines a power level of power generated by at least one generator of the at least one wind turbine and feeds the generated power at least partly to the power-to-gas converter when the determined power level reaches or exceeds a given lower threshold value. Additionally, the invention relates to a wind turbine or a group of wind turbines. Wind turbines are highly correlated renewable energy sources. The power generated by a wind turbine is largely dependent on the current wind speed. Although a relatively constant power output may be achieved once the wind speed reaches a certain threshold value, in many cases wind turbines operate within an unstable portion of the operating time under wind speed conditions where the power output is strongly related to the wind speed. If most of the power in the grid is provided by wind turbines, for example by an offshore wind farm, it will be necessary to provide sufficient power even at low wind speeds. However, this will result in a very high power output at higher wind speeds. This may require enlarging the grid to handle high power output and may also be problematic for economic reasons. An alternative would be to burn off the remaining power, for example by heating resistors, controlling the wind turbine to produce less power or similar waste methods. It would in principle also be possible to use other energy sources, such as gas power plants, within the same grid to compensate for power fluctuations. However, this may be undesirable when maximum use of renewable energy is desired. To alleviate this problem, it is known from the prior art to use at least part of the electricity generated by the wind turbine to drive an electricity-to-gas converter, such as an electrolyzer, to generate hydrogen. Examples of this method are disclosed in documents US 5592028A, US 7075189A and US 7199482A. Document US 7471010 suggests the use of wind turbine towers as gas storage facilities. The gas produced can be converted back into electrical energy, as discussed for example in document WO 02/084839 A2. Document CN 107769 255A discloses a variable speed constant frequency wind power generation system. At low wind speeds and during rotation of the wind turbine at low speeds, the quality of the generated electrical energy is insufficient to feed it to the grid, and thus the electrical energy is fed exclusively to the electrolyzer to generate hydrogen. Once the cut-in speed is reached, the generator stops supplying power to the electrolytic cell and is connected to the grid. The power is then increased as the wind speed increases until the rated power is reached. Once the wind turbine reaches rated power, the generator additionally supplies at least one electrolytic cell to further increase the total power. A method of providing a relatively constant power level to the grid during a relatively short time interval is discussed in document WO 2013/087553 A1. The document suggests predicting a minimum wind speed and thus a minimum power output for a given prediction interval, and then limiting the power level supplied to the grid to or below that level. The remaining power is then used to drive the power-to-gas converter. Although this approach improves the predictability of the power output of the wind turbine, the power level provided to the grid may still vary strongly over time, especially if relatively short prediction intervals are used. However, using a long prediction interval with strong wind speed variations will result in a relatively large reduction of the amount of power that can be output to the grid, and also requires a relatively large capacity of the power-to-gas converter, which may significantly increase the cost of the wind turbine. It is therefore an object of the present invention to provide a method for operating at least one wind turbine which at least partly alleviates the problem of high peak power output to the grid when the wind turbine is providing a large amount of power, while at the same time allowing for a relatively low cost of implementation of the wind turbine. Preferably, the method should allow a relatively constant power output to the grid under a wide variety of usage conditions. This problem is solved by the method for operating at least one wind turbine initially discussed, wherein the amount of power fed to the power-to-gas converter is kept constant when the determined power level reaches or exceeds a given upper threshold value. By keeping the power fed to the power-to-gas converter constant once the determined power level reaches or exceeds the upper threshold value, the capacity of the power-to-gas converter used can be freely selected. As will be discussed in detail below, it i