The Future of Electricity
Keeping birds off the wire
Birds and electricity just don’t get along.
Power outages can be caused by direct contact when birds fly into transmission and distribution lines. Or when birds try to perch or nest on electric utility structures.
Fresh bird droppings cause disturbances in power transmission. Or accumulated, dried droppings damage equipment.
Birds cause one of every four power outages.
While damage from birds causes interruptions to reliable electrical service, damage to birds is also a problem.
For many birds, an encounter with electrical equipment means instant death. And strict federal laws protect many bird species.
The Institute of Electrical and Electronics Engineers recently put together a task force to research the kinds of problems that birds cause electric utilities—and to propose some solutions.
Ravi Gorur, a professor of electrical engineering at Arizona State University in Tempe, says, “I like to solve real-life problems, so this task force was of great interest to me. My co-researcher, Raji Sundararajan, and about 10 other engineers gathered information from utilities, then published our findings in scholarly scientific journals. Now we are publishing our data in more widely read magazines, such as Transmission and Distribution World, to help utilities deal with the problems of birds.”
The task force discovered that different kinds of birds cause different kinds of problems.
Raptors (large hunting birds such as eagles, hawks, and owls) are attracted to lofty perches above open ground. To a raptor, a tall power line support pole above a cleared right-of-way seems just like a bare tree in the middle of a perfect hunting ground. But these birds’ huge wingspans can mean making an accidental connection between pieces of equipment that interrupts the flow of power—and kills the bird.
Perching birds that travel in huge flocks may try to roost on utility structures—and leave so many droppings that the mess interferes with the flow of electricity. In some areas, migratory birds passing through an area collide with power lines.
Keeping birds and electrical equipment safely separated requires a variety of approaches, and utility companies are modifying existing equipment in several ways.
Transformers, lines, and poles can be reconfigured so that there is enough space between elements to accommodate local birds’ wingspans.
Sometimes installing a taller pole that does not contain any electrical equipment will serve as a decoy. This substitute perch or nesting platform will be more attractive and area birds will ignore electrical equipment.
Utility equipment can also be insulated differently to prevent accidental electrocution. Other devices can make power lines more visible to flying birds.
These modifications can be thought of as “bird-friendly” solutions. Other approaches take a more unfriendly approach to saving birds.
To prevent electrocution, some utilities are adding pointed baffles, slippery surfaces, and other barriers that make it impossible for birds to gain a foothold on electrical equipment. These techniques can save birds’ lives by making it harder for them to come in contact with energized equipment.
Some utilities are using scare tactics, like noise, to frighten birds away.
Dr. Gorur says, “The problem with scare tactics and similar techniques is that birds are very smart. After about two weeks they often figure out that manmade noises are really no threat.”
Avian Systems Corporation of Louisville has come up with a solution for many utilities in the region. Vice President Ankit Chudgar says, “Using microphones to recognize when certain bird species are present, we can then broadcast distress calls and other sounds only when needed to drive the birds from the area. In 1999, we installed our system at a Meade County Rural Electric Cooperative substation near Brandenburg to combat a large flock of starlings. When starlings are present, day or night, our system broadcasts 30 to 45 different sounds in random order. Some are the sounds of natural predators and birds in distress, and some are manmade sounds. This prevents the birds from getting used to a certain pattern so this system has been effective for a long time.”
“Thinking like a bird” may be the key to successfully keeping birds away from power lines. Engineers and utility company workers agree that preventing bird encounters is an important defense against outages and damage.
To read more about Dr. Gorur’s research, visit this Web site: http://tdworld.com/mag/power_birds_ power_lines/
Next month: TVA in the 21st century