Abstract: Abstract: Aiming at the fire accidents caused by overload, short circuit and equipment aging of indoor power transformer, the mechanism of transformer fire heat radiation and toxic gas diffusion is studied, and the effective method of power transformer fire suppression is sought. Taking 10 kV oil immersed power transformer as an example, a fire test platform was built to simulate the early fire scene of indoor power transformer. The gas concentrations of CO, NO, SO2 and O2 before and after the fire were collected. According to the test data, we analyzed the variation law of temperature and thermal radiation at different locations of the fire scene, and used perfluorohexanone fire extinguishing agent to suppress the fire of transformer at last. The test results show that perfluorohexanone extinguishing agent has fast fire extinguishing speed and has obvious effect of heat absorption and cooling. The cooling rate can reach 80 ℃/min. This test is not destructive to the electrical equipment of transformer in the fire of indoor power transformer. It realizes the controllability of indoor transformer fire and the improvement of fire extinguishing efficiency. It is a new idea for the research on fire suppression of power transmission and transformation system equipment.

Key words: Key words: perfluorohexanone, indoor transformer fire, fire extinguishing test