Senvion could not have achieved 10 GW installed worldwide without the help of its 3.XM series turbines, more specifically the 3.4M104 and 3.2M114, the latter of which was recently launched in Canada.
The 3.4M104 platform led to the development of the 3.XM series, Senvion said. All 3.XM series turbines are characterized by a modular, hybrid construction allowing for a greater degree of flexibility. The hybrid construction combines a standard steel tower with prefabricated concrete segments.
Coming in at 3.4 MW, the 3.4M104 has the largest nameplate rating of the series, but the smallest rotor diameter at 104 m and shortest hub heights ranging from 80 to 100 m. Consequently, this turbine also has the smallest swept area at 8,495 m2 and the shortest blade length at 50.8 m. But don’t let those numbers fool you, the 3.4M104’s compact size—in relation to the other turbines in the series—results in greater economic efficiency. Senvion calls it the “solution for challenging locations,” meaning high wind environments.
With a larger rotor (114 m), swept area (10,207 m2) and longer blade length (55.8 m) compared to the 3.4M104, the 3.2M114 can increase energy yield by up to 10%, said Senvion. Optimized for medium wind speeds, the 3.2M114 is available in three hub heights: 93, 123 and 143 m. Featuring the tallest hub height of the series, this turbine towers above nature’s obstacles, generating high energy yield in rugged terrain. It also has a hot air, de-icing system.
A three-stage planetary and spur gearbox maximizes efficiency of a high-speed generator at low rotor speeds, effectively minimizing sound levels—the 3.2M114 is one of the quietest turbines in its class. The electrical system consists of a generator (double-fed induction in the 3.4M104 and squirrel cage induction in the 3.2M114) and liquid-cooled converter that offer a low-loss solution for converting mechanical energy into electrical energy.
The dc pitch system is comprised of three motors operating independently for a fail-safe design that provides an emergency brake when needed. Battery backup for each rotor blade offers additional support during power failures. Blade bearings with permanent track lubrication and external gearing along with an integrated deflector in the spinner protect the pitch system from the elements.
The designs are also built to handle large gusts. For instance, a tilted cone concept “combines a 5° incline of the integrated drivetrain and the pre-bending of the rotor blades,” said Senvion. This combination permits effective weight distribution and safe load transfer. The degree of incline also produces enough distance between the rotor blades and tower to prevent a rotor strike.
Likewise, the yaw system uses hydraulic residual braking power, which allows for “load-minimized operation,” even in high wind. Additionally, four-point roller bearings ensure smooth movement during wind tracking.
Although currently only offered in Europe, the 3.4M104 has seen a high success rate thus far, totaling more than 850 MW installed in five countries, according to Senvion statistics. While the 3.2M114 only has 500 MW installed to date, with its debut in Canada, the 3.2M114 may soon surpass its sister turbine in terms of total megawatts installed.
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