Recently, the problem of the availability factor being lower than that originally anticipated has become manifest with wind power stations built on complex terrains. In other words, troubles have occurred such as an extreme decrease in the generation output, failures of components inside and outside wind turbines like yaw motors and yaw gears, and cracking on wind turbine blades. As one of the causes of the occurrence of these troubles, the effects of wind turbulence (terrain-induced turbulence) is pointed out. In this study, we investigated and studied the effects of terrain-induced turbulence on the structural strength of wind turbines through the measurement of strains in wind turbine blades and of wind condition data in order to establish a method of optimum arrangement of wind turbines based on numerical wind condition data with the conditions of structural strength of wind turbines taken into consideration. The investigation and study were conducted on wind turbine 10 of the Kushikino Reimei Wind Power Station in cooperation with Kyudenko New Energy Corporation (commissioned in November 2012). Following this, we conducted numerical wind condition simulation (diagnosis of terrain-induced turbulence) of the effects of the properties of air flow on the structural strength of wind turbines from the viewpoint of numerical wind conditions, by using an actual terrain version of RIAM-COMPACT based on large eddy simulation (LES), and we successfully reproduced the characteristics of wind conditions and the structure of three-dimensional air flow. These results, to be reported below, have enabled us to determine the threshold values for the quantitative optimum arrangement plan on the basis of the actual terrain version of RIAM-COMPACT.

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