Abstract: In order to study the combustion and extinguishing characteristics of the large- scale ultra- high voltage converter (UHV converter)pool fire, the UHA converter fire model was built, an experimental platform for fire extinguishing was designed. By pool fire and foam-water mist combined fire extinguishing experiment, the fire plume temperature around the UHV converter was analyzed. We found that the combustion behavior of tested pool fire is similar to the actual UHV converter fire. The wall attachment phenomenon and air entrainment effect were obvious, and the highest temperature is located in the valve side. The wall temperature of the converter increased rapidly, the yield strength of the steel was reduced, and the structure was deformed. But the internal transformer oil and firewall heated up slowly. Foam water mist combined system can extinguish the large- scale UHV converter fire quickly, and the cooling effect and oxygen dilution effect were obvious.

Key words: fire safety UHV converter, fire, combustion characteristics, foam-water mist combined system