Abstract: Through the investigation of actual fire cases, this paper summarizes the experience and lessons of transformer fire at home and abroad, and analyzes the causes of transformer fire and the weak parts of pressure bearing. The paper points out the design and construction technical defects of transformer fire extinguishing system, and carries out the fire extinguishing test of transformer fire,such as shielding fire, internal and external fire, compound fire,etc., which is compared with the fire extinguishing effect of commonly- used transformer fire extinguishing system. Some suggestions are put forward, such as improving the technical standard of fire protection, perfecting the design, construction, maintenance and strengthening the fire safety management.

Key words: fire protection, transformer, fire case, fire extinguishing system