Studies of Vibrations from Wind Turbines in the Vicinity of the Eskdalemuir (AS104) IMS Station

Abstract

Styles et al (2005) describe an extensive microseismic and infrasound monitoring programme to characterise the low-frequency vibration spectra produced by wind turbines of various types, both fixed and variable speed. They demonstrated that small but significant harmonic vibrations (modal eigentones) of the towers, excited by blade passing, tower braking and wind loading while parked, can propagate many kilometres and be detected on broadband seismometers. This meant that protective measures were required to protect the IMS seismic monitoring station (EKA), located at Eskdalemuir in the Scottish Borders, UK. Over 2 GW capacity of wind turbines were planned for this region and planning restriction were imposed to control development because of potential effects on the IMS station. This work established that vibrations of concern in the 2 to 6 Hz band, while small, were critical for this monitoring. Propagation laws were derived and an aggregate vibration budget established which would not prejudice the operation of Eskdalemuir, to aid planning and permit appropriate wind farm development. Subsequently, further work has been carried out to determine if small wind turbines (<50kW) should be covered by the same restrictions as large turbines. The UK Ministry of Defence has now issued new guidelines that should allow small wind projects to be developed in the vicinity of Eskdalemuir after modeling and measurement confirms that they do not generate significant vibrations within the band of concern. The work may have relevance to other IMS sites where new windfarm developments are planned or already exist.

Citation

Studies of Vibrations from Wind Turbines in the Vicinity of the Eskdalemuir (AS104) IMS Station

• Publication Date: Jun 1, 2011
• Series Title: Comprehensive Nuclear Test Ban Treaty: Science & Technology 2011
• Publisher URL: http://www.ctbto.org/specials/ctbt-science-and-technology-20118-10-june-2011-vienna-austria/ctbt-science-and-technology-2011/