A method for accurately producing the drilled hole in a wall of a component fabricated by investment casting process, such as for use in a blade or steam turbine includes the following steps. The 3D data of actual component is obtained from the measurements or from the numerical simulation. The actual model and the ideal model are aligned and compared, a series of cutting planes are given to establish a series of 2D cross-sections of the actual and ideal models after registration. Each cross-section is dispersed into discrete points, the distance between each corresponding points are calculated and formed into 2D displacement. The accurate parametric model consisting of the depth, hole center, and the nominal vector is obtained on the basis of considering the deviations in geometrical and positional values. The drilled hole is then produced according to the corrected parametric drilled-hole geometrical and positional value.

A method for controlling a wind power installation, wherein the wind power installation has a rotor with a plurality of rotor blades, the rotor blades are adjustable in their blade angle, each rotor blade is activatable individually, for the individual activation, in each case a total adjustment rate R.sub.of which indicates an intended speed of change of the respective blade angle is predetermined, a collective blade angle identical for all of the rotor blades is provided, a collective adjustment rate identical for all of the rotor blades describes an intended speed of change of the collective blade angle, an individual offset angle which indicates a value by which the blade angle is intended to deviate from the collective blade angle is predetermined for each rotor blade, an individual feed forward control adjustment rate which indicates an adjustment rate which is provided for reaching the offset angle is determined for each rotor blade from the individual offset angle, an individual offset deviation is determined for each rotor blade depending on a comparison of the individual offset angle and a detected blade angle of the rotor blade, and the total adjustment rate of each rotor blade is determined depending on the collective blade angle and/or the collective adjustment rate, the individual feed forward control adjustment rate, and the individual offset deviation.

The present invention relates to a control system for thrust-limiting of wind turbines, which wind turbine comprises at least one tower, which tower carries at least one nacelle which nacelle comprises a rotating shaft, which shaft is rotated by one or more blades, which blades at pitch regulated by a pitch control system. It is the object of the present invention to reduce mechanical load and stress of a wind turbine. A further object is to reduce the maximal load on tower of a wind turbine. The thrust-limiting control system performs control of the pitch angle, which thrust-limiting control system performs regulation of the pitch angle based on at least a first input from a wind estimator and a second input from a turbulence estimator. By thrust-limiting control, reduction in the maximum mechanical load on a tower, or maybe also a nacelle, can be achieved by a relatively high percentage of the load in a way where it has only very limited influence on the power production of the wind turbine.

A method for accurately producing the drilled hole in a wall of a component fabricated by investment casting process, such as for use in a blade or steam turbine includes the following steps. The 3D data of actual component is obtained from the measurements or from the numerical simulation. The actual model and the ideal model are aligned and compared, a series of cutting planes are given to establish a series of 2D cross-sections of the actual and ideal models after registration. Each cross-section is dispersed into discrete points, the distance between each corresponding points are calculated and formed into 2D displacement. The accurate parametric model consisting of the depth, hole center, and the nominal vector is obtained on the basis of considering the deviations in geometrical and positional values. The drilled hole is then produced according to the corrected parametric drilled-hole geometrical and positional value.

The present invention relates to a control system for thrust-limiting of wind turbines, which wind turbine comprises at least one tower, which tower carries at least one nacelle which nacelle comprises a rotating shaft, which shaft is rotated by one or more blades, which blades at pitch regulated by a pitch control system. It is the object of the present invention to reduce mechanical load and stress of a wind turbine. A further object is to reduce the maximal load on tower of a wind turbine. The thrust-limiting control system performs control of the pitch angle, which thrust-limiting control system performs regulation of the pitch angle based on at least a first input from a wind estimator and a second input from a turbulence estimator. By thrust-limiting control, reduction in the maximum mechanical load on a tower, or maybe also a nacelle, can be achieved by a relatively high percentage of the load in a way where it has only very limited influence on the power production of the wind turbine.

A method of calibrating a yaw actuator of a wind turbine is provided, including steps of performing an active yaw operation in a clockwise yaw direction and an active yaw operation in a counter-clockwise yaw direction; recording data of a wind direction and a power caused by both yaw operations, and averaging the data and calculating an error between an experimental power difference and a theoretical power difference of yaw operations in the clockwise direction and a counter-clockwise direction; determining a minimum of the error; and determining a yaw misalignment based on the minimum error.

The present disclosure relates to methods (100, 200) for ramping up the power output of a wind turbine (10). A method (100) comprises increasing (110) electric power output from an initial power value (61) at a first power ramp rate (63); and when reaching an intermediate power value (69), increasing (120) the electric power output to a target power value (59) at a second power ramp rate (67) different from the first power ramp rate (63). The intermediate power value (69) is the sum of the initial power value (61) and a predetermined power difference (71).

Provided are an off-grid wind-hydrogen energy supply system for polar regions and a control method thereof, and relate to the field of new energy supply. In the system, wind energy is converted by a wind power generation system into electric energy, and a cryogenic battery energy storage system is charged. Chemical energy of hydrogen and oxygen is converted by a hydrogen fuel cell system into electric energy, and the cryogenic battery energy storage system is charged. Energy is stored by the cryogenic battery energy storage system, a wind power fluctuation is mitigated, and a load is smoothened. Operation parameters of the wind power generation system, the cryogenic battery energy storage system, and the hydrogen fuel cell system are obtained by an intelligent monitoring system.

A system and method for predicting power output of a wind farm are disclosed. The method includes determining first and second parameter values of a power curve for a plurality of wind turbines. A second relationship is determined between the densities associated with the wind turbines and the values of the first parameter. A third relationship is determined between the densities associated with the wind turbines and the values of the second parameter. A value of the first parameter for a specified wind farm density is determined based on the second relationship. A value of the second parameter for the specified wind farm density is determined based on the third relationship. An indication of a power output for the specified wind farm density is generated by applying the determined values of the first and second parameters to the power curve.