Building on previous revisions and the knowledge gained through both project experience and cold chamber testing, and also taking into account the new GL Guideline for the Certification of Wind Turbines 2010, this is the fourth revision of the note since its introduction. GL first issued the note in 2005 and has been continually revising and updating it ever since, to reflect advances in technology and growing expertise gained through the continued testing of turbines in extreme temperatures, both in the field and in the lab.
The latest technical note provides information on load assumptions, safety and control systems, manuals, rotor blades, nacelle covers and spinners, machinery components, strength verification, building structures, and electrical installations.
A site is considered a cold climate site if minimum temperatures of below -20°C have been observed during long term measurements on an average of more than nine days a year, for a minimum of one hour. If a site fulfils these conditions then cold climate requirements should be considered in the design of the turbine.
GL Renewables Certification has a long history of working with wind turbines under such extremes of temperature, having certified several projects in sub-artic areas, including Rushlake Creek in Saskatchewan, Canada as well as the Chanarambie, Viking and Stoneray projects in Minnesota, USA. Furthermore, many components and wind turbines have been assessed successfully based on former editions of this Technical Note.