Inertial response function for grids with high turbine penetration

1. A method for compensating at least partially a frequency deviation in a grid, the method comprising:

determining a grid frequency,

applying the grid frequency to a grid frequency criterion,

in case the grid frequency meets the grid frequency criterion,

determining a first set of wind turbines from a wind turbine power plant fleet based on the grid frequency criterion to provide a first stepped response at a first frequency, and

transmitting a command for a first transient frequency response to the first set of wind turbines to provide the first stepped response at the first frequency wherein the command to cause extraction of kinetic energy from a rotor of each wind turbine in the first set of wind turbines;

determining a second set of wind turbines from the wind turbine power plant fleet to provide a second stepped response at a second frequency where the first frequency and the first set of wind turbines are different from the second frequency and the second set of wind turbines;

transmitting a command for a second transient frequency response to the second set of wind turbines to provide the second stepped response at the second frequency to cause extraction of kinetic energy from a rotor of each wind turbine in the second set of wind turbines; and

delivering to the grid the kinetic energy of the first stepped response by the first set of wind turbines and the kinetic energy of the second stepped response by the second set of wind turbines.

2. The method as set forth in claim 1 , further comprising:

in case the grid frequency meets the grid frequency criterion,

determining a strength of the first transient frequency response for the first set of wind turbines based on the grid frequency criterion, and

transmitting the command for the first transient frequency response to the first set of wind turbines, including the strength of the transient frequency response.

3. The method as set forth in claim 1 , further comprising:

in case the grid frequency meets the grid frequency criterion,

determining the strength of the first transient frequency response individually for each wind turbine from the first set of wind turbines, and

transmitting the command for the first transient frequency response individually to each wind turbine from to the first set of wind turbines, including the respective strength of the first transient frequency response.

4. The method as set forth in claim 1 , further comprising:

in case the grid frequency meets the grid frequency criterion,

determining an amount of additional power needed from the wind turbine power plant fleet based on the grid frequency criterion, and

determining the first set of wind turbines from the wind turbine power plant fleet based on the amount of additional power needed.

5. The method as set forth in claim 2 , wherein:

determining the strength of the first transient frequency response for the first set of wind turbines is further based on an amount of additional power needed.

6. The method as set forth in claim 3 , wherein:

determining the strength of the first transient frequency response individually for each wind turbine from the first set of wind turbines is further based on an amount of additional power needed.

7. The method as set forth in claim 1 , wherein:

determining the first set of wind turbines and the second set of wind turbines from the wind turbine power plant fleet is further based on the number of wind turbines being online in the wind turbine power plant fleet.

8. The method as set forth in claim 2 , wherein:

determining the strength of the first transient frequency response for the first set of wind turbines is further based on the number of wind turbines being online in the wind turbine power plant fleet.

9. The method as set forth in claim 3 , wherein:

determining the strength of the first transient frequency response individually for each wind turbine from the first set of wind turbines is further based on the number of wind turbines being online in the wind turbine power plant fleet.

10. The method as set forth in claim 2 , wherein:

determining the strength of the first transient frequency response for the first set of wind turbines is further based on an average energy production level of the wind turbines in the wind turbine power plant fleet.

11. The method as set forth in claim 3 , wherein:

determining the strength of the first transient frequency response individually for each wind turbine from the first set of wind turbines is further based on an individual energy production level of the respective wind turbine.

12. The method as set forth in claim 1 , further comprising:

in case the grid frequency meets the grid frequency criterion,

determining a time period for the first transient frequency response for the first set of wind turbines based on the grid frequency criterion, and

transmitting the command for the first transient frequency response to the first set of wind turbines, including the time period of the first transient frequency response.

13. The method as set forth in claim 1 , further comprising:

providing at least two grid frequency sub-criteria, and

in case the grid frequency meets one of the at least two grid frequency sub-criteria,

setting this grid frequency sub-criterion as the grid frequency criterion.

14. The method as set forth in claim 13 , further comprising:

performing a stepped transient frequency response, by using at least two of the grid frequency sub-criteria.

15. A grid operating device for compensating a frequency deviation in a grid, the grid operating device comprising:

a grid frequency determination unit for determining a grid frequency,

a grid frequency comparison unit for comparing, if the grid frequency meets a grid frequency criterion,

a wind turbines determination unit for determining a first set of wind turbines to provide a first stepped response at a first frequency and a second set of wind turbines to provide a second stepped response at a second frequency from a wind turbine power plant fleet based on the met grid frequency wherein the first set of wind turbines and the first frequency are different from the second set of wind turbines and the second frequency, and

a transient frequency response command transmission unit for transmitting a command for the first stepped response to the first set of wind turbines to cause extraction of kinetic energy from a rotor of each wind turbine in the first set of wind turbines to deliver the kinetic energy of the first set of wind turbines to the grid and for transmitting a command for a second stepped response to the second set of wind turbines to cause extraction of kinetic energy from a rotor of each wind turbine in the second set of wind turbines to deliver the kinetic energy of the second set of wind turbines to the grid.

16. The method as set forth in claim 1 , further comprising:

determining a third set of wind turbines from the wind turbine power plant fleet to provide a third stepped response at a third frequency where the first set of wind turbines and the second set of wind turbines are different from the third set of wind turbines and the third stepped response is different from the first and second stepped responses;

transmitting a command for a third transient frequency response to the third set of wind turbines to provide the third stepped response at the third frequency to cause extraction of kinetic energy from a rotor of each wind turbine in the third set of wind turbines; and

delivering to the grid the kinetic energy of the third stepped response by the third set of wind turbines.

17. The grid operating device as set forth in claim 15 , wherein the wind turbines determination unit for determining a third set of wind turbines to provide a third stepped response at a third frequency;

wherein the transient frequency response command transmission unit for transmitting a command for the third stepped response to the third set of wind turbines to cause extraction of kinetic energy from a rotor of each wind turbine in the third set of wind turbines to deliver the kinetic energy of the third set of wind turbines to the grid; and

wherein the first set of wind turbines and the second set of wind turbines are different from the third set of wind turbines and the third stepped response is different from the first and second stepped responses.