Method for operating a wind turbine, wind turbine and computer program product

1. A method for operating a wind turbine, the method comprising:

in response to receiving a request for a system start of the wind turbine, monitoring at least one measured value over a predetermined monitoring period; and

effecting the system start in response to determining that the at least one measured value in the monitoring period corresponds to defined specifications, wherein:

the at least one measured value is stored continuously in a data storage and a storage period in the data storage corresponds to at least the predetermined monitoring period, and

monitoring the at least one measured value in response to receiving the request for the system start comprises checking, on the basis of the data storage, whether the at least one measured value in a storage period corresponding to the monitoring period before the request corresponds to the defined specifications.

2. The method of claim 1 , wherein the data storage is a ring buffer.

3. The method of claim 1 , wherein at least two measured values are stored continuously in the data storage and checked upon the request for the system start.

4. The method of claim 3 , wherein differing monitoring periods or storage periods are specified for the at least two measured values.

5. The method of claim 3 , wherein differing monitoring periods and storage periods are specified for the at least two measured values.

6. The method of claim 1 , wherein reference data are stored continuously in the data storage over a storage period, the reference data are configured for checking plausibility of the at least one measured value, and the storage period of the reference data corresponds at least to the monitoring period of the at least one measured value to be checked for plausibility.

7. The method of claim 6 , comprising in response to finding a plausibility deficiency, emptying the data storage.

8. The method of claim 6 , wherein the plausibility checking is based on at least one of maximum values, minimum values, gradients, mean values, and standard deviations.

9. The method of claim 6 , wherein the reference data include at least one of an angle of attack of the rotor blades and a rotor rotational speed.

10. The method of claim 1 , wherein the at least one measured value or the reference data that are stored in the data storage are checked for plausibility during the continuous storage or during the checking of the at least one measured value upon the request for a system start.

11. The method claim 1 , wherein the at least one measured value comprises a measurement of at least one of wind direction, wind speed, nacelle azimuth position, tower head acceleration, tower vibration signals, temperature of the environment, and temperature of individual components of the wind turbine.

12. The method of claim 1 , wherein the monitoring period is at least 60 seconds.

13. The method of claim 1 , wherein the at least one measured value and the reference data that are stored in the data storage are checked for plausibility during the continuous storage or during the checking of the at least one measured value upon the request for a system start.

14. The method of claim 1 , wherein the monitoring period is at least 120 seconds.

15. A wind turbine comprising:

a rotor having a plurality of rotor blades, the rotor being rotatably arranged on a nacelle that is arranged on a tower;

a generator arranged in the nacelle for converting wind energy acting on the rotor into electrical energy;

at least one sensor for sensing at least one measured value;

a data storage for continuously storing the sensed at least one measured value for a storage period; and

a closed-loop control system for controlling the wind turbine, wherein the control system is configured for verifying, in response to a request for a system start, on the basis of the data storage, whether the at least one measured value in the period corresponding to a predetermined monitoring period corresponds to predefined specifications before the request, wherein the storage period corresponds to at least the predetermined monitoring period, and the closed-loop control system is configured to start the wind turbine verifying that the at least one measured value corresponds to the predefined specifications.

16. The wind turbine of claim 15 , wherein the data storage is a ring buffer.

17. A non-transitory computer readable medium comprising instructions that, when executed by a computer processor of a wind turbine, cause the wind turbine to:

in response to receiving a request for a system start of the wind turbine, monitor at least one measured value over a predetermined monitoring period; and

effect the system start in response to determining that the at least one measured value in the monitoring period corresponds to defined specifications, wherein:

the at least one measured value is stored continuously in a data storage and a storage period in the data storage corresponds to at least the predetermined monitoring period, and

monitoring the at least one measured value in response to receiving the request for the system start comprises checking, on the basis of the data storage, whether the at least one measured value in a storage period corresponding to the monitoring period before the request corresponds to the defined specifications.