Extinguishment of a transformer fire with a long projection water mist system

Author：Zhu, X., Chen, G., Wang, Z., Wu, L., Luo, J., Wang, X.

Journal：Fire Safety Journal

DOI:  10.1016/j.firesaf.2022.103603

Keywords: Water mist, Spray characterization, Fire extinguishment, Axial flow induced spray, Transformer fire, full-scale experiments, suppression, Engineering, Materials Science

Abstract: 

When large oil-immersed power transformer fire happens, scenarios such as bushing explosion, oil pool fire, oil spray fire and oil flowing fire are commonly observed. As the nozzles of current water mist or sprinkler system are arranged in the fire region, they are at risk of damage during the explosion or under high temperature. This paper presents a long projection water mist technique based on axial flow inducing to effectively extinguish the fire at far distance. The droplet size, spray density, and effective spray distance were characterized via Laser diffraction technique, water collection method and laser distance measurement. Fire extinguishment tests were conducted through setting up a full-scale 800 kV converter transformer model to verify its capability. The results indicate that the proposed system can extinguish the 800 kV converter transformer fire within dozens of seconds, due to its long spray distance, small droplet size, and large spray density. This study will provide a new method for water mist generation and references for system design for large transformer fire or oil fire extinguishment in open space.