Research on Key Parameters and Fire Extinguishing Effectiveness of Compressed Air Foam System Used for UHV Substation

Compressed air foams (CAFs) system has proved to be highly effective to generate uniform and highly stable foam, showed a great potential application in ultra-high voltage (UHV) substation. But the key parameters of the system are not focused deeply. In this paper, an experimental platform was established to study the effect of system parameters of CAFs on foam jet capability, including the nozzle aperture, flowrate, liquid–gas ratio, jet angle, and ambient wind speed. Also, fire extinguishing performance of the CAFs was evaluated after parameter optimization. The results show that there is an optimal nozzle aperture range, and the foam jet distance can be increased by increasing the flowrate, liquid–gas ratio, and angle. The offset degree of foam jet path increases with the increase of wind speed. The methods to improve the wind resistance of foam include increasing the nozzle aperture, decreasing the flowrate, and changing the jet angle. The CAFs have a high performance of extinguishing transformer oil fire, but it gradually decreases with the increase of fire source position under ambient wind. This paper can provide guidance for the design of CAFs system used in UHV substation.