Fire simulation tests of mineral oil and natural esters transformers

This paper describes the work carried out by the Italian Institutional Working Group on Natural Esters; this Group has been promoted by the University of Roma 'La Sapienza', the National Firefighters Authority, the National Institute for Insurance against Accidents at Work (INAIL) and the Department for Geological Survey of Italy (ISPRA) with the objective of further validating the real possibility of risk mitigation for humans and environment through a more widespread use of a new generation of transformers insulated with natural ester liquids. A useful contribution to the activities of the Italian Institutional Group on Natural Esters has been also given by the participation of some of the major players in the electrical sector, such as: Italian TSO, main Distributors, Natural Ester producers and transformer manufacturers. The development of this Italian Group at international level has been the set-up of the CIGRE WG D1.68 'Natural and synthetic esters - Evaluation of the performance under fire and the impact on environment', which is actually preparing a report on this subject. The present paper reports the main results of experimental comparative fire simulations of both mineral oil and natural esters distribution transformers.