Page 298 - Fluid Power Engineering

264 Chapter Twelve

IMPACTS up to
3 km IMPACTS up to 18 km
–Partial Attenuation –Multi-path Scatter
of Radar Beam –Multiple Elevation
–Personnel Safety Scans Impacted
(within 200 meters) –Bulk Cable
–Limited or No Interference
Workarounds
–Difficult to work
around IMPACTS within RLOS
–Clutter
Impact –Algorithm Impacts
–Some Workarounds
Available

0 2 4 6 8 10 12 14 16 18 20 2224 26 28 3032 34 36 38 40
Distance between Wind Farm & Radar (Kilometers)

FIGURE 12-3 This graph shows how wind turbine clutter impacts on weather
forecast office (WFO) operations vary with distance (approximate) from the
Weather Surveillance Radar-1988, Doppler (radar). The impacts (blue line)
curve upward (increase), as turbines are sited closer to the radar. Impacts
increase quickly very close to the radar. Two key distances are 11 and
2 miles. These distances delineate where additional impacts generally begin
(assuming a level terrain). The distances of these impacts can vary by many
miles depending on terrain and weather conditions. (Courtesy of the
WSR-88D Radar Operations Center). 11

1 km prevent forming of proper radar beam leading to signif-
icant degradation of radar performance; turbines within 18
km can cause clutter.
3. Air traffic control software could temporarily lose track of an
aircraft that is flying over a wind farm. 12 Wind farms create
a vertical “cone of silence” and when an aircraft flies into it,
the radar system has difficulty detecting the plane. On the
civilian side, this is an issue only with smaller planes that do
not have transponders.
4. Normally, an air traffic control radar system will filter out
large returns from stationary targets, but the Doppler shifts
introduced by the WTG blades are interpreted as moving
aircraft that can confuse radar operators and compromise
safety 12

Conventional radar’s clutter filters are ineffective in removing
clutter signal reflected from moving blades of a fixed turbine. A study
12
by MITRE finds that there are no fundamental technical constraints
that prevent detection of clutter caused by wind turbines. The problem
is the aging long-range radar infrastructure that was not designed to