Modal Testing of Advanced Wind Turbine Systems

The U.S. Department of Energy (DOE), in conjunction with the U.S. wind industry, is supporting the development of technology for advanced, higher efficiency wind energy conversion systems. Under the Turbine Development Program (TDP), the DOE, through the National Renewable Energy Laboratory (NREL) will assist U.S. industry in incorporating advanced wind turbine technology into utility-grade windturbines. As part of the TDP, NREL is conducting a range of activities aimed at assisting the wind industry with system design analysis and testing. One major activity is NREL's Full System Modal Testing (FSMT) task. In 1993 and 1994, NREL's FSMT team conducted modal surveys on several wind turbine systems developed by the U.S. wind industry, including Atlantic Orient Corporation's AOC 15/50, R.Lynette and Associates' (RLA) AWT-26 P1, and Carter Wind Turbines Incorporated's CWT-300. This paper describes how these modal surveys were carried out and how industry and NREL wind researchers used the experimental results to validate their analytical models.