AWEA Blog - New US test facility to improve wind turbines

The 5-megawatt dynamometer test facility is the newest addition at the center, which is part of the Golden-based National Renewable Energy Laboratory.

The new facility is an upgrade from a 2.5-megawatt dynamometer at the center.

“As wind turbines have gotten bigger and bigger, we needed a bigger test facility,” said center director Fort Felker.

Land-based turbines now generate as much as 3 megawatts, and offshore turbines can generate 6. There are new turbines pushing the power output even higher.

“We need a larger platform and one that could integrate with a simulated grid,” Felker said.

The facility was financed through a U.S. Department of Energy grant.

The drivetrain of a wind turbine — usually atop a tower and connected to a propeller — is placed in the dynamometer, and instead of wind, it is turned by an electric motor.

Using a variety of gears and drive shafts, and a 6-megawatt motor, the machine can simulate various wind conditions and drive the turbine at top speeds for long periods — a key manufacturing test.

The new facility can create not just the effect of the torque of a spinning wind blade but also the turbulent winds and stress that can hit a turbine, Felker said.

Another of the new site’s added capabilities is its simulated power grid — the Controllable Grid Interface.

The interface allows researchers to see how turbines respond in situations such as overvoltage or undervoltage events.

“This gets us closer to creating the experiences the turbines will face in the real world,” Felker said.

The interface will also enable NREL engineers to find ways that wind systems can help support the grid, Felker said.

Turbines now have a “low-voltage ride-through” that enables them to continue to operate when faults occur on the grid.

They also have power electronics giving turbines the capability to match the grid’s electrical frequency and help support grid stability.

“These control technologies enable wind turbines to become the grid’s best friend,” Felker said.

The first tests being done at NREL are on a 2.75-megawatt wind turbine that the Energy Department acquired in partnership with General Electric Co.

“The only way to deliver advanced technology at a lower cost of energy with high reliability is to be able to test and learn,” Tom Fischetti, a senior GE engineering manager, said at the facility’s December dedication.

“Being able to do that here at ground level instead of in the field, 300 feet in the air, is very important to GE and the rest of the wind industry,” Fischetti said.