Experimental Study and Application of Unmanned Aerial Vehicle Releasing Fire-Extinguishing Bomb on Transmission Line Wildfires

Experimental studies on the application of unmanned aerial vehicles (UAVs) to extinguish high-repeatability transmission line wildfires are not available. In this study, a scheme involving a UAV releasing a fire-extinguishing bomb at a high altitude for firefighting was proposed, and a simulated fire-extinguishing experimental platform was constructed to simulate a UAV releasing a fire-extinguishing bomb. In addition, the characteristics of water-based fire-extinguishing bombs of 5, 10, 20, and 50 kg as well as dry powder bombs of 25, 30, and 50 kg were investigated by changing parameters such as the type and mass of the fire-extinguishing agent carried by the bombs. It was noted that a 30 kg or more dry powder fire-extinguishing bomb could extinguish a fire in four 1A cribs at one time. The diffusion area of the fire-extinguishing medium was obtained from the perspective of the UAV. The diffusion area was 45–90 m2 for the water-based fire-extinguishing bomb and 130–700 m2 for the dry powder bomb. As calculated from the area of the fire scene extinguished by each fire-extinguishing bomb per unit mass, the utilization rate of a fire-extinguishing medium was highest with the 30 kg fire-extinguishing bomb, followed by the 50 kg bomb. In the high wildfire incidence period during the Qingming Festival in 2024, a UAV was used to release fire-extinguishing bombs to extinguish an incipient wildfire near a transmission line at a Hunan Power Grid site.