Comparison of Measured Wind Park Load Histories with the WISPER and WISPERX Loading Spectra

    Research output: NRELTechnical Report


    The blade-loading histories from two adjacent Micon 65/13 wind turbines are compared with the variable-amplitude test loading histories known as the WISPER and WISPERX spectra [1). These standardized loading sequences were developed from blade flapwise load histories taken from nine different horizontal axis wind turbines operating under a wide range of conditions in Europe. The subject turbinescovered a broad spectrum of rotor diameters, materials, and operating environments. The final loading sequences were developed as a joint effort of thirteen different European organizations. The goal was to develop a meaningful loading standard for horizontal-axis wind turbine blades that represents common interaction effects seen in service. In 1990, NREL made extensive load measurements on twoadjacent Micon 65113 wind turbines in simultaneous operation in the very turbulent environment of a large wind park located at the San Gorgonio Pass, California. Further, before and during the collection of the loads data, comprehensive measurements of the statistics of the turbulent environment were obtained at both the turbines under test and at two other locations within the park. The trendto larger but lighter wind turbine structures has made an understanding of the expected lifetime loading history of paramount importance. Experience in the U.S. has shown that the turbulence-induced loads associated with multi-row wind parks in general are much more severe than for turbines operating individually or within widely spaced environments. Multi-row wind parks are much more common inthe U.S. than in Europe. In this paper we report on our results in applying the methodology utilized to develop the WISPER and WISPERX standardized loading sequences using the available data from the Micon turbines. While the intended purpose of the WISPER sequences were not to represent a specific operating environment, we believe the exercise is useful, especially when a turbine design islikely to be installed in a multi-row wind park.
    Original languageAmerican English
    Number of pages10
    StatePublished - 1995

    NREL Publication Number

    • NREL/TP-442-7226


    • blades
    • horizontal-axis
    • standards
    • wind turbines


    Dive into the research topics of 'Comparison of Measured Wind Park Load Histories with the WISPER and WISPERX Loading Spectra'. Together they form a unique fingerprint.

    Cite this