GE Energy has expanded its 1.5-MW series of wind turbines to include the 1.5xle model, designed for efficient operation in weak wind areas, the company announced at HUSUMwind 2005.

A prototype of the 1.5xle wind turbine recently was connected to the grid at the Klondike Wind Farm in Sherman County, Oregon to begin its performance testing phase, which is scheduled for completion by the end of the year.

"With the introduction of the 1.5xle, GE's 1.5-MW series now is available with the ideal rotor diameter for every wind classification," said Ulrich Uphues, platform manager, 1.5-MW series for GE Energy's wind segment.

GE's 1.5se wind turbines feature a rotor diameter of 70.5 meters for strong or class I wind areas; the 1.5sle has a 77-meter rotor diameter, ideal for class II; and the new 1.5xle offers a rotor diameter of 82.5 meters, for class III or weaker wind applications. GE's 1.5-MW family of wind turbines also offers an extreme cold-weather package that provides for operation at temperatures as low as -30°C, and in survival mode without operation, at temperatures as low as -40°C.

For the prototype 1.5xle unit, a few mechanical adjustments were required to accommodate the larger rotor diameter. "The pitch bearing, pitch system, rotor hub and blades, gears and towers were enhanced to meet the higher demands," explained Uphues.

Test bed trials for the 1.5xle ran for two months, with successful results. The new machine's LM 40 rotor blade has been specifically adapted to meet the operational requirements, and also underwent extreme-load and fatigue testing.

The 1.5xle series is available with tower heights of 58.7, 80 and 100 meters. The tallest version also is available in solid steel form with no concrete foundation.

Building on the experience and lessons learned from a fleet of more than 3300-MW-plus wind turbines, GE Energy is also launching its new 2.5 and 3-MW machines.

Evolving from GE's earlier 2.x megawatt series design, first introduced in 2003, the new 2.5 and 3-MW machines introduce a number of industry innovations, including a permanent magnet generator, a modular converter with full power conversion and advanced control technologies.

GE already has successfully tested a 2.5-MW prototype wind turbine, which was installed in May 2004 at Wieringermeer, the Netherlands, about 50 kilometers north of Amsterdam. Installation of the first 3-MW machine is planned for the summer of 2006. Both the 2.5 and the 3-MW wind turbines are expected to be commercially available in Europe by the end of 2006.

At the heart of the new wind turbines is a force flow optimized bedplate, which joins all nacelle components on a common structure, providing increased durability. The new 2.5-MW machine will be available with a 100-meter rotor diameter, while the 3-MW wind turbine will offer both 90 and 94-meter rotor diameters; these increased rotor sizes offer higher energy capture. Advanced control features, including a sophisticated pitch regulation system with power/torque control capability, and improved use of the drive train damper mitigate the increased loads of the larger rotor.

Both new units also employ a highly efficient permanent magnet synchronous generator, enabling higher efficiency at lower wind speeds. A new bearing design substantially increases the life and reliability of the gearbox by preventing bending and thrust loading produced in the rotor from impacting the gearbox. An advanced lubrication system, designed to increase reliability and lower operation and maintenance costs, automatically lubricates pitch, yaw, main and generator bearings.

A modular, full-power converter allows for simplified, more effective power quality control functions including harmonics, reactive power and flicker. Acting as a buffer, the converter protects both the generator and the gear box from the harmful effects of weak grid systems. It also enables the machine to be easily outfitted with GE's Low Voltage Ride-Through (LVRT) electronics, which enable wind turbines to stay on-line, producing power even during severe grid disturbances.

Compatible with both 50 and 60-Hz grid systems, the new wind turbines also include an on-board crane, designed to simplify service and minimize cost.