Method for detecting an accretion of ice on a wind turbine

Patent metadata

Field	Value
Publication number	US-12092085-B2
Application number	US-202017438338-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Mar 11, 2019
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A method for detecting an accretion of ice on a rotor blade of a rotor of a wind turbine is provided. The can be operated at a variable rotational speed. The method includes recording a wind speed of a wind acting upon the rotor, recording an operating variable that is dependent on the wind speed and comparing the recorded operating variable or the recorded wind speed with a reference variable of a characteristic wind-speed-dependent operating-variable curve of the wind turbine. The characteristic operating-variable curve indicates an operating variable assumed to be optimal in dependence on the wind speed. The method includes detecting an accretion of ice on the rotor blade if the recorded operating variable or the recorded wind speed, deviates from the reference variable by at least a predetermined minimum deviation specified in dependence on the wind speed.

First claim

The invention claimed is:

1. A method for identifying an accretion of ice on a rotor blade of a rotor of a wind turbine, comprising:
recording a wind speed of wind acting on the rotor, the rotor being operable at a variable rotational speed;
recording an operating variable that is dependent on the wind speed, wherein recording the operating variable includes:
recording an output power generated by the wind turbine from the wind as the operating variable for wind speeds below a rated wind speed, and
recording a blade angle set to limit the output power as the operating variable for wind speeds above the rated wind speed;

comparing the recorded operating variable or the recorded wind speed with a reference variable of a characteristic operating curve of the wind turbine, wherein the characteristic operating curve indicates the operating variable based on the wind speed; and
identifying the accretion of ice on the rotor blade in response to the recorded operating variable or the recorded wind speed deviating from the reference variable by at least a minimum deviation, wherein the minimum deviation is specified based on the wind speed, wherein a minimum power deviation, a minimum angle deviation or a minimum speed deviation is specified in dependence on the wind speed; and
in response to identifying the accretion of ice on the rotor blade, operating the wind turbine in a curtailed mode or starting a heating process of the wind turbine.

2. The method as claimed in claim 1 , wherein:
the recorded operating variable is a recorded output power generated by the wind turbine from the wind, a recorded rotor rotational speed of the wind turbine, and/or a recorded blade angle set to limit the output power,
comparing the recorded operating variable or the recorded wind speed with the reference variable includes:
comparing the recorded output power with a reference power of a characteristic operating power curve of the wind turbine, or comparing the recorded wind speed with a wind speed assigned to the recorded output power via the characteristic operating power curve, the characteristic operating power curve indicating a maximum output power based on the wind speed,
comparing the recorded rotor rotational speed with a reference rotational speed of a characteristic rotational speed curve of the wind turbine, or comparing the recorded wind speed with a wind speed assigned to the recorded rotor rotational speed via the characteristic rotational speed curve, the characteristic rotational speed curve indicating a maximum rotor rotational speed based on the wind speed, and/or
comparing the recorded blade angle with a reference angle of a characteristic blade angle curve of the wind turbine, or comparing the recorded wind speed with a wind speed assigned to the recorded blade angle via the characteristic blade angle curve, the characteristic blade angle curve indicating an optimal blade angle based on the wind speed, and

identifying the accretion of ice on the rotor blade in response to the recorded operating variable or the recorded wind speed deviating from the reference variable by at least the minimum deviation includes identifying the accretion of ice on the rotor blade in response to:
the recorded output power deviating from the reference power by at least the minimum power deviation, or the recorded wind speed deviating from the wind speed assigned to the recorded output power by the minimum speed deviation,
the recorded rotor rotational speed deviating from the reference rotational speed by at least a minimum rotational speed deviation or the recorded wind speed deviating from the wind speed assigned to the recorded rotor rotational speed by the minimum speed deviation, the minimum rotational speed deviation being specified based on the wind speed, and/or
the recorded blade angle deviating from the reference angle by at least the minimum angle deviation or the recorded blade angle deviating from the wind speed assigned to the recorded blade angle deviates by the minimum speed deviation.

3. The method as claimed in claim 2 , wherein
the characteristic blade angle curve is specified depending on a reduced operating limit that is a reduced power limit and/or a reduced rotational speed limit, and
the minimum angle deviation is specified based on the reduced operating limit.

4. The method as claimed in claim 1 , wherein
the minimum deviation is specified using a deviation curve, and the deviation curve indicates a behavior of the operating variable based on the wind speed, and wherein:
the deviation curve deviates from the characteristic operating curve by the minimum deviation, and a varying distance is obtained between the characteristic operating curve and the deviation curve,
the deviation curve is not shifted by a constant wind speed value relative to the characteristic operating curve, and/or
the deviation curve deviates from the characteristic operating curve by wind speed values of differing magnitude.

5. The method as claimed in claim 1 , wherein:
in partial-load operation, the minimum power deviation increases at least one of: from a first start-up wind speed, from a wind speed threshold or continuously, and
in full-load operation, the minimum angle deviation decreases with increasing wind speed.

6. The method as claimed in claim 1 , wherein the wind turbine is operated using a rotational speed power characteristic having the output power of the wind turbine set based on a recorded rotational speed of the rotor.

7. The method as claimed in claim 1 , wherein the accretion of ice on the rotor blade is detected only in response to a recorded outside temperature being below a maximum temperature.

8. The method as claimed in claim 1 , comprising:
setting the characteristic operating curve during operation of the wind turbine, and/or
setting the characteristic operating curve during operation of the wind turbine includes recording operating deviations representative of deviations of the recorded operating variable from an operating variable according to the characteristic operating curve and that are not due to the accretion of ice, and wherein:
the minimum deviation is selected such that it is greater in magnitude than a corresponding operating deviation.

9. The method as claimed in claim 1 , comprising:
determining multiple times in a predefined test period whether the recorded operating variable or the recorded wind speed deviates from the reference variable by at least the minimum deviation; and
identifying the accretion of ice in response to a positive determination for a majority of the multiple times.

10. The method as claimed in claim 1 , comprising:
setting three wind speed sections for a lower wind-speed range, setting the three wind speed sections including:
setting the three wind speed sections to be equally sized;
setting a first wind speed section that extends from a start-up wind speed at which the wind turbine starts up to a first section wind speed;
setting a second wind speed section that extends from the first section wind speed to a second section wind speed; and
setting a third wind speed section that extends from the second section wind speed to the rated wind speed, wherein
the minimum deviation in each of the three wind speed sections increases with increasing wind speed, and at least one of:
the minimum deviation increases continuously from the first wind speed section to the third wind speed section with increasing wind speed,
a mean minimum deviation of the third wind speed section is at least 50% greater than a mean minimum deviation of the second wind speed section, and/or
the mean minimum deviation of the second wind speed section is at least 50% grea

Assignees

• Wobben Properties Gmbh

Inventors

• Messing Ralf
• Senftleben Daniel

Classifications

• F05B2270/328

  Blade pitch angle · CPC title

• F05B2270/327

  Rotor or generator speeds · CPC title

• F05B2270/32

  Wind speeds · CPC title

• F05B2270/309

  Rate of change of parameters · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title