Abstract: Provided is a method for adapting an operating characteristic of a wind power installation. The installation has a rotor with rotor blades having adjustable blade angles and operable with a variable rotor rotational speed. To control the installation, use is made of an operating characteristic which describes a relationship between the rotor rotational speed and an operating variable. The operating characteristic has a first portion with a first rotational speed range and a second portion with a second rotational speed range. The first rotational speed range has lower rotational speeds than the second rotational speed range, and the operating characteristic is adapted such that values of the operating variable of the first portion are increased values of the variable of the second portion are changed toward higher rotational speeds, and an expected total number of revolutions of the rotor over a predetermined lifetime of the installation remains approximately the same.

Abstract: Provided is a displaceable maintenance device, to a displaceable assembly device, to a method for servicing a fastening element, and to a method for servicing and/or assembling a fastening element of a flange of a wind power installation tower. Provided is a displaceable maintenance device for a wind power installation tower, comprising a mobile unit which is specified for moving the maintenance device along a flange of the wind power installation tower; a first maintenance unit having an impact element for impacting a fastening element, in particular a flange connection element, and a noise-receiver unit for detecting a noise generated by the impacting; a control unit for evaluating the noises detected by means of the noise-receiver unit, said control unit, based on the evaluation, being specified for assigning a maintenance status to a fastening element.

Abstract: A method for operating a wind turbine, in particular at a location characterized by a cold climate is provided. The method includes, specifying an air density at a location of the wind turbine, setting a blade angle of an adjustable rotor blade based on an output power, torque and/or rotor speed. The method includes setting the blade angle as a function of a at pitch characteristic curve which specifies the blade angle as a function of the output power, the torque and/or the rotor speed and as a function of the air density. According to the pitch characteristic curve, the blade angle has a minimum as a function of the air density in a region of a reference density of an atmosphere at the location which is characterized by a cold climate.