Method for ascertaining a value of an ice buildup quantity on at least one rotor blade of a wind turbine, and use thereof

A method for determining a value for an ice buildup quantity on at least one rotor blade of a wind turbine, comprising:

• determining a base value for at least one natural frequency of the rotor blade when vibrations are excited in an ice-buildup-free state;
• determining a shift base factor for a shift of the at least one natural frequency in relation to the ice-buildup-free state in the case of an ice buildup quantity that has been increased by a specific value;
• capturing a measurement value or a measurement value curve of a measurement variable that is suitable for identifying the current natural frequencies of the rotor blade;
• identifying the current natural frequencies of the rotor blade;
• deriving a current shift factor by comparing the current natural frequencies to the base value;
• comparing the current shift factor to the shift base factor;
• deriving a value for the ice buildup quantity on the basis of the comparison,
• wherein one value for the ice buildup quantity is determined in each case on at least two rotor blades of the wind turbine, further comprising:
• comparing the values for the respective ice buildup quantity;
• and
• determining by means of the comparison whether or not the imbalance of the rotor of the wind turbine exceeds a value that is set or settable in advance.

A method for determining a value for an ice buildup quantity on at least one rotor blade of a wind turbine, comprising:

• determining a base value for at least one natural frequency of the rotor blade when vibrations are excited in an ice-buildup-free state;
• determining a shift base factor for a shift of the at least one natural frequency in relation to the ice-buildup-free state in the case of an ice buildup quantity that has been increased by a specific value;
• capturing a measurement value or a measurement value curve of a measurement variable that is suitable for identifying the current natural frequencies of the rotor blade;
• identifying the current natural frequencies of the rotor blade;
• deriving a current shift factor by comparing the current natural frequencies to the base value;
• comparing the current shift factor to the shift base factor;
• and
• deriving a value for the ice buildup quantity on the basis of the comparison,
• wherein the specific value of the increased ice buildup quantity is 20 kg or less.