Experimental Investigation of the Combustion Behavior of Transformer Oil Jet Flame

Abstract

Transformer oil jet fire is one of the most dangerous types of fires in substations. The combustion behavior of transformer oil jet fire produces uncontrollable hazards to personnel and equipment and even triggers a domino effect. However, the jet fire combustion behavior of such materials as transformer oil has not been revealed before. Investigation of the combustion behavior of transformer oil jet fire has positive implications for the prevention and control of substation fires. In this paper, KI25X transformer oil was used as fuel. A series of transformer oil jet fire experiments were conducted with variable orifice diameters (5, 10, and 15 mm) with heat release rates ranging from 200 to 659.2 kW. The results showed that the entrainment coefficient of transformer oil jet fire was greater than that of pure gas phase jet fire. The entrainment coefficient of transformer oil jet fire was 0.029. Using dimensionless theory, it was proposed that the imaginary point source was proportional to the 0.317 power of Froude number. Based on the point source model, a dimensional analysis model with Reynolds number was developed. The radiation fraction of transformer oil jet fire was proportional to the −0.133 power of Reynolds number. This study played an important role in improving the jet combustion behavior of transformer oil.

Simulation Study on Fire Combustion Process of Oil Immersed Transformer

“…Oilimmersed transformers are the most common type of power transformer with high voltage levels, complex working conditions, high operating temperatures and enormous dimensions [5]. It contains a large amount of flammable liquid insulating oil inside, which, in the event of a fire, often spreads easily and is difficult to extinguish, posing a safety risk to operators and a risk of soil surface water contamination [6]. At the same time, the unstable operation of the grid can also have a negative impact on social and economic development [7], so it is vital to ensure the safe operation of transformers.…”