General
The wind power plant WTN 600 is a pitch-controlled turbine
with completely variable speed for operation parallel to the
public grid. The rated output of the plant is 600 kilowatt;
the rotor diameter is 46 or 48 meters. The rotor has
three blades and is arranged in upwind position to the tower.
Yawing into the wind is achieved by two electrically driven
yaw systems. For the tower you can choose between a 50m
tubular tower or a 65m lattice tower.
The mechanical concept of the nacelle is based on a three-point-fixing of the main bearing together with the main gear unit and a two-generator system.
The WTN 600 operates with variable speed. The rated power of both asynchronous generators comes to 330 kilowatts each. Two frequency converters are installed to feed the electrical power to the grid. The turbine is designed corresponding to type class 2A according to IEC TC 88.
Rotor
The rotor consists of three low noise and power optimized rotor blades with a self-supporting structure of epoxy resin, reinforced by glass fibre. Through the application of glass fibre fabric, a high strength is obtained. The lightning protection is integrated in the blade.
Pitch system
Each rotor blade has its own pitch drive with a maintenance-free servomotor, a gear unit and a spring storage unit. To reach the best output, the rotor blades work independently, but altogether they are synchronized electronically. In case of grid failures a spring unit serves as energy storage for the movement of the rotor blade back to the sail position. It is connected directly to the blade bearing and drives the rotor blade in the neutral sail position within a few seconds.
Drive unit
The rotor blades are connected with a two-rowed four-point contact bearing to the casted hub, that is optimized by FEM-analysis. Through the forged flanged shaft the rotation is transmitted to the main gear. The three-point-fixing of the main drive unit takes up all axial forces in the main bearing at the front of the flanged shaft, while the radial forces are transmitted to the nacelle frame by the bearings mounted to both sides of the main gear. The connection between the main gearing and the nacelle frame is realized by bushings. Their rubber elements damp the sound of the gearbox from the frame and guarantee a quiet and noiseless operation of the whole wind turbine.
Electrical system
The electrical energy is produced by two squirrel cage induction generators with a rated output of 330 kW each. By means of a flexible and isolated coupling they are connected to the shaft of the gearbox.
For each generator a frequency converter is installed, which allows an independently energy delivery. Depending on the wind speed one or both converters will be in operation. The frequency converter reaches high grid quality with the integrated filters to eliminate interferences like harmonics and there is no extra compensation required for reactive power.
Control system
An extensive sensor technology is installed to control all functional and safety procedures permanently by a computer-aided management system. The interaction of pitch and frequency converter of the variable speed controlled plant guarantees the highest utilization from the wind energy.
A control unit suited inside the tower respectively next to it allows all operations, protected by passwords, from downstairs. Via modem or ISDN it is also possible to control the operations by a remote supervision.
Safety concept
The primary brake and safety system is the independent blade pitch of the rotor. The pitch control does not only optimize the power output; it limits also the rated power to avoid undesirable overloads. Any information to the control system, which influences the safety of the plant, is answered by an immediate reaction of the pitch control.
The rotor remains without brakes and thereby relieves the driving unit. A disk brake on the high-speed shaft of the gearbox is operated pneumatically when the emergency switch is engaged. It can also be operated by a handle as a brake system for maintenance.
Service life
All components of the WTN 646 are designed for a technical service life of 20 years. The installation of standardized, tested components and the operating system, controlled by torque, guarantee the safe function and optimum energy output in the long run of lifetime.
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Click here for brochure WTN600 (PDF 2,4 MB) 
