2012: Trends in obstruction lighting

Although obstruction lighting on wind turbines is critical for safety, wind-farm owners and operators are looking for new ways to keep this necessary component cost effective. To do this, a growing trend is toward lights that consume low power, don’t weight much, and are easy to install. Another trend is using lights that minimize the visual impact on the environment. Lastly, the light must operate in harsh conditions, so engineers are beefing-up fixtures with monitors to alert operators of problems.

Ray Kraemer with TWR Lighting sees a trend in reducing the light pollution surrounding turbines. “Companies are focused on community-friendly designs with almost no light directed below the beacon’s horizon,” he explains. “Many are easy to install by on-site personnel.” Furthermore, Kraemer says lighting fixtures are becoming more ‘high-tech’. “Some designs now include a built-in power module, controller, and GPS synchronizer that makes the light simple to install and lets them operate reliably under harsh conditions,” he says. “All this helps minimize capital costs and costs of ownership.” Other designs also include a flash circuit and photocell.

Engineers from Dialight, a manufacturer of obstruction lighting, say using a compact flash head can reduce wind load on fixtures. Also, smaller units—less than 8.5-in. high—are shock and vibration resistant to provide a lowest profile to reduce the impact of wind shear on the structure. This makes it well-suited for high altitudes where it will work reliably in inclement weather.

Because met towers are traditionally located well away from 120-V lines, engineers are looking for alternative power sources for lighting. Flash Technology engineers say a solution could be obstruction lights that run on solar power. These systems are significantly smaller and lighter, and so use half the power of previous versions. Such small systems also maintain the smallest beam pattern allowed under FAA/CAR/ ICAO standards, and still work without moving parts.

Another trend is using LED instead of incandescent lighting. Flash Technology engineers say red LED beacons run on 24 to 48 Vdc so conduit is not required. Installation is made even easier because the lights mount onto existing bolt hole patterns. The lights are highly efficient, using 97% less energy than incandescent fixtures, only 12 W in flash mode and 24 W steady. While medium-intensity obstruction lighting may be assets to airplanes, they are sometimes an annoyance to local communities. In response to this problem, Dialight engineers say the current trend is toward optics to minimize ground scatter and nearly eliminate community-light pollution.

Also, sharp beam cutoffs offer a lower level of scatter—below 0.1 millifootcandles—over a mile, while delivering an FAA required 2,000 candelas to passing aircrafts. In the past, LED and incandescent beacons could scatter more than 0.3 millifootcandles and disturb residential areas, but Dialight says the new design almost eliminates observable light pollution on the ground. These units are also easy to retrofit from existing incandescent fixtures, and can last 10 years longer than previous versions. That significantly reduces maintenance costs and risky tower climbs associated with outdated beacon equipment. WPE