Containment of blast phenomena in underground electrical power plants

Gas explosion accidents in electrical power plants can be originated by electrical faults in components containing oil for insulation, such as transformers, junction boxes, etc. A ground discharge can cause the pyrolysis of part of the oil and the production of a gaseous mixture, which can generate fires or deflagrations in contact with air. A deflagration gives rise to a pressure shock wave, which can propagate throughout the underground plant if not suitably confined. Fluid-dynamic, structural and, in some cases, fluid-structure interaction analyses are needed to evaluate the overpressures occurring during the blast phenomena and the consequent damages on structural elements. In the present paper, a numerical approach to this kind of problem is proposed and applied to a case study dealing with a typical transformer cell in an underground power plant. The fluid-structure interaction code PLEXIS-3C is used to perform both fluid and structural fast dynamic computation. (C) 1998 Elsevier Science Ltd.