Dynamometer Test Facilities
Dynamometers enable industry and testing agencies to verify the performance and reliability of wind turbines drivetrain prototypes and commercial machines. Designs are tested by simulating operating field conditions in a laboratory environment. In a typical dynamometer test, a powerful motor replaces the rotor and blades of a wind turbine. Wind turbine dynamometer testing focuses on the mechanical and electrical power-producing systems of a wind turbine including generators, gearboxes, power converters, bearings, brakes, lubrication, cooling, and control systems.
The National Wind Technology Center (NWTC) offers wind industry engineers a unique opportunity to conduct a wide range of tests. Its custom-designed dynamometers can test wind turbine systems from 1 kilowatt (kW) to 5 megawatts (MW).
The illustration of the NWTC 2.5-MW dynamometer (right) shows how a wind turbine drivetrain is coupled and tested. The test turbine is rigidly fixed to a foundation and coupled through its low speed main shaft to the dynamometer. Rotational energy supplied by the dynamometer is converted to electrical energy by the turbine's generator. Electrical power generated by the operating turbine is returned to the dynamometer through the local electrical grid. Depending on test objectives, non-torque loading actuators may be utilized to apply large thrust, bending, and shear loads normally generated by the turbine's rotor.
NWTC Dynamometer Test Capabilities
Dynamometers are an effective means by which new designs can be validated because the "wind" input into the turbine can be simulated without waiting for nature-driven events to occur. During steady state, or "static" testing, a series of speed/torque points along the turbine's power curve are imposed by the dynamometer, for a fixed period of time, to evaluate mechanical and electrical performance. Points outside the turbine's normal operating range can be selected to assess response to extreme events or to conduct Highly Accelerated Life Tests (HALT). By intentionally overloading a turbine in a HALT test, a lifetime of wear and tear is applied during a reasonable period of testing. To gain a better understanding of a turbine's mechanical, electrical, and control system response in real-world conditions, "model-in-the-loop" techniques are employed to replace the rotor, tower, pitch, and yaw systems with computer simulations operating in real time.
The NWTC's new 5-MW dynamometer can be connected either directly to the grid or to a controllable gird interface (CGI), providing system engineers with a better understanding of how wind turbines react to grid disturbances. Get more facts on the dynamometer and watch the above video to see how it—and the CGI—work.
NWTC dynamometer facilities are available for industry users. Contact the NWTC for testing inquiries at 303-384-6900.