The impact detection system uses vibration sensors mounted to turbine blades and an optical camera on the tower base. Source: Oregon State University
Bird and bat collisions with turbines are often cited as the downside of wind energy systems. An impact detection system based on vibration sensors was designed at Oregon State University to improve assessments of wind turbine-related avian and bat mortality.
The conceptual design of a system that auto-detects collisions features a vibration sensor at the base of a blade, an acoustic sensor on the generator housing to pick up bird sounds and an optical camera on the tower base. When a bird strikes one of the blades, the impact is detected by the vibration sensor on that blade. Footage recorded by the camera and audio of any bird cries recorded by the acoustic sensor is then used to determine the species of bird or bat involved.
The researchers simulated bird impacts by using a compressed-air launcher to fire tennis balls at turbines. Data from 29 field tests with blade strikes showed positive detection and confirmation 14 times. Most of the detected strikes occurred at the leading edge of the blade halfway between the blade’s midpoint and tip. The results demonstrate the feasibility of triggering the system through a single impact event sensed by vibration sensors, say the researchers.
A related project underway involves development of a computer-connected camera to determine if an approaching bird is an eagle and whether it’s flying toward the blades. If both those answers are yes, the computer would trigger a ground-level kinetic deterrent: randomly moving, brightly colored facsimiles of people, designed to play into eagles’ apparent aversion to humans.
When a vibration sensor detects a thump, recorded video data from the camera could be examined to tell if the impact was caused by an eagle or something else.
