Methods for operating wind turbines and charging auxiliary power sources
The present disclosure relates to methods for operating wind turbines ( 10 ) and charging one or more auxiliary power sources ( 84 ) for providing auxiliary power to one or more wind turbines ( 10 ). A method comprises pitching the wind turbine blades ( 22 ) to a predetermined idling pitch angle such that the wind turbine generator ( 42 ) produces power for charging one or more auxiliary power sources ( 84 ) above a predetermined wind speed. The method further comprises keeping the pitch angle ( 25 ) of the blades ( 22 ) at the idling pitch angle and charging the auxiliary power sources ( 84 ) when a prevailing wind speed reaches or exceeds the predetermined wind speed.
1 . A method for operating a wind turbine that includes a rotor with a plurality of blades and a generator, wherein the wind turbine is configured to supply electrical power from the generator to one or more auxiliary power sources in an autonomous mode of operation, the method comprising:
determining whether a predetermined condition for idling operation of the wind turbine is met;
when the predetermined condition for idling operation is met, pitching the blades to a predetermined idling pitch angle at which the generator can produce power for charging the auxiliary power sources during idling within a predetermined wind speed range;
maintaining the pitch angle of the blades at the predetermined idling pitch angle during idling;
charging the auxiliary power sources when a prevailing wind speed is within the predetermined wind speed range;
wherein the predetermined idling pitch angle is between 60° and 75° such that the rotor rotates at least at 2 RPM during idling when the blades are at the idling pitch angle;
the idling pitch angle predetermined for wind speeds within the predetermined range of 8 m/s to 20 m/s; and
wherein charging of the auxiliary power sources during the idling operation is alternated between charging and non-charging by: maintaining the blades at the predetermined idling pitch angle for a first predetermined period of time, thereafter positioning the blades to a feathered pitch angle for a second predetermined period of time, and thereafter positioning the blades back to the predetermined idling pitch angle.
2 . The method of claim 1 , wherein determining whether a condition for idling operation is met comprises determining whether a dangerous condition is present.
3 . The method of claim 1 , wherein determining whether a condition for idling operation is met comprises determining whether a condition to reduce or to stop supplying power to an electrical grid is met.
4 . The method of claim 3 , further comprising reducing or stopping the supply of power to the electrical grid.
5 . The method of claim 1 , wherein determining whether a condition for idling operation is met comprises determining whether the wind turbine is unable to withdraw power from an electrical grid.
6 . The method of claim 1 , wherein determining whether a condition for idling operation is met is performed during normal operation of the wind turbine.
7 . The method of claim 6 , further comprising starting the autonomous mode of operation.
8 . The method of claim 1 , wherein determining whether a condition for idling operation is met is performed when the wind turbine is in the autonomous mode of operation.
9 . The method of claim 8 , further comprising restarting the autonomous mode after depletion of the auxiliary power sources and their subsequent charging at or above the predetermined wind speed.
10 . The method of claim 1 , wherein the idling pitch angle is maintained at least until a condition for stopping idling operation is detected.
11 . The method of claim 10 , wherein the idling pitch angle is maintained at least until the wind turbine recovers connection with a grid.
12 . A wind turbine, comprising:
a rotor including a plurality of blades;
a generator;
a control system;
wherein the wind turbine is configured to supply electrical power from the generator to one or more auxiliary power sources in an autonomous mode of operation;
the control system configured to perform the method according to claim 1 .
13 . A method for operating a wind turbine that includes a rotor with a plurality of blades and a generator, wherein the wind turbine is configured to supply electrical power from the generator to one or more auxiliary power sources in an autonomous mode of operation, the method comprising:
when the wind turbine is in the autonomous mode of operation, pitching the blades to a predetermined idling pitch angle;
idling the wind turbine rotor at the predetermined idling pitch angle;
charging the auxiliary power sources when a rotor rotational speed in idling is at or above a rotational speed threshold;
wherein the predetermined idling pitch angle is between 60° and 75° such that the rotor rotational speed in idling is at least 2 RPM during idling;
the predetermined idling pitch angle is determined for wind speeds within a range of 8 m/s to 20 ms;
changing the pitch angle of the blades when a predetermined operational condition is met; and
wherein charging of the auxiliary power sources during the idling operation is alternated between charging and non-charging by: maintaining the blades at the predetermined idling pitch angle for a first predetermined period of time, thereafter positioning the blades to a feathered pitch angle for a second predetermined period of time, and thereafter positioning the blades back to the predetermined idling pitch angle.
14 . The method of claim 13 , wherein the predetermined operational condition includes recovering the ability to withdraw power from the electrical grid.
15 . The method of claim 13 , wherein the predetermined operational condition includes triggering of an alarm due to high wind speeds.