RE: We love wind -- or do we?

["Jaro" <jaro-10kbq@sympatico.ca>]

Anyone care to guess what happens when you combine a transfer of energy

(lightning & associated light & UV radiation) with windmills ?



http://www.huronwind.com/huronwind/hw_pdfs/40.pdf

August 27, 2003 - Lightning strikes blade



Turbine No. 4 shutdown for repairs

Lighting strikes blade

The Huron Wind farm was disconnected from the electrical grid on Aug. 21

when power lines from the site were damaged by a fierce storm that knocked

down limbs and trees along the Bruce County shoreline.

During the storm, Turbine No. 4 sustained damage to one of its blade from a

lightning strike.

"The damage to the blade will be assessed in greater detail when the crane

arrives to allow personnel to get a closer view,. said Liz Cussans, Project

Manager.

When the crane is on site, generators in three of the turbines will also be

changed out to correct a manufacturing flaw that has caused the units to

trip on occasion. Two other units had the same type of generators changed

out earlier in the year and this week.s repairs will complete the

initiative. The generators are maneuvered in and out of a trap door in the

nacelle with the crane.

The turbine blades have a glass-fibre skin that covers a foam-layered metal

rod that runs from the tip of the blade to the rotor hub. The skin provides

a flat surface for wind while the rod provides strength. A metal button is

located on the outside of each blade to direct charges from potential

lightning strikes through the rod to the ground.

"Heat from strikes can cause the air inside the blades to heat up and

expand," advised Cussans. "The expansion can damage the blades by causing

them to split along the edges."

Although the damage to the Turbine No. 4 appears to be limited to a blade

tip, the most extreme measure would be to replace the blade. If the injury

is superficial, the skin of the blade can be repaired in place with fibre

tape in the same manner as a boat.

Three of the five Huron Wind units returned to service the morning following

the storm.

Repairs are expected to be complete in early September.

<end quote>



Jaro

http://www.cns-snc.ca/branches/quebec/quebec_main.html







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