Contribution to the study of transformer tank rupture due to internal arcing development of a computer simulation tool

Transformer explosions are caused by electrical arcs occurring in the insulating oil. They generate dynamic pressure waves that propagate in the tank and interact with its structure leading to its explosion. This whole process was studied using experiments performed on large scale transformers. Moreover, to accurately study the phenomena exhibited during this experimental campaign and in order to minimize the costs and the risks of the testing, a computational tool was developed to simulate the transformer explosion. An unsteady compressible 2-phase flow approach was used and viscous flow, electromagnetic, thermal and gravity effects are taken into account. The equations are solved using a finite volume method on unstructured mesh, allowing computing complex 3D transformer geometries. Comparisons between experiments and simulations validate the model that can thus be used to study explosions of large transformer tanks and their prevention by fast-direct-tank-depressurization-based methods.