Power Transformers and Environmental Protection

Power transformers are among the most expensive equipment installed in power plants and substations. Generally, they contain large quantities of combustible material which can, in the event of ignition, spread fire to adjacent installations. The cause of such a serious fault is a short circuit inside the transformer due to dielectric oil insulation rupture. The energy of the created electrical arc is exchanged to liquid oil and this results in a massive and instant oil vaporization and creation of large volume of explosive and flammable gases. Consequently, the pressure inside the vessel is increasing rapidly. This paper describes a unique protection, Fast Depressurization System (FDS) developed by French company SERGI which is capable to release the pressure within milliseconds, evacuate explosive gases to a safe environment and save the transformer from explosion. The paper states the characteristics of the FDS, describes its principles and operation, its comparison with the conventional pressure protections such as PRV, and inquire about its practical application within energy sector in Czech and Slovak Republic. The paper mentions the current requirements of EU directives on environmental protection which the above mentioned FDS fully meets.