th International Conference on Electricity Distribution Turin, 6 -9 June 2005 C I R E D Session Number 01 RESEARCH AND EXPERIMENTAL CHARACTERIZATION OF ALTERNATIVE MATERIALS TO REDUCE ENVIRONMENTAL IMPACT OF ELECTRICAL DISTRIBUTION EQUIPMENT R. Berti, F. Barberis, A. Colombo, F.Curcio, M. Saottini † CESI Italy berti@cesi.it, barberis@cesi.it, ancolombo@cesi.it, curcio@cesi.it, saottini@cesi.it A research project named MATEALT started in CESI at the end of 2003 with a funding regulated by the Decree of the Italian Ministry for Industry and Trade dated 26 January 2000. The project is in progress and its aim is to improve the eco- profile of some of the main electrical components, studying and testing the following materials: carbon dioxide as an alternative to SF 6 for dielectric applications and arc extinguishing medium in MV circuit breakers: CO 2 has the lowest GWP value among all greenhouse gases and its arc decomposition fragments don’t give products so hazardous in presence of moisture, air and construction materials like SF 6 products; ester-based oils for paper-oil transformers as an alternative to mineral oil for reducing soil and water pollution in the event of an accidental spill and providing enhanced fire safety: a synthetic ester oil and a seed ester fluid are chosen for their higher biodegradability, flash and fire points than mineral oil characteristics and for a very low toxicity, a good dielectric breakdown and readily disposability; polymeric materials from recycling to replace the metal enclosure of MV switchgears for MV/LV substation: depletion of non renewable resources and waste production can so be reduced. In such a way the installation of some electrical components in town and natural land of the country can be supported in full agreement with environmental and safety regulations and meeting the public opinion. In this paper the results of breakdown voltage tests on CO 2 and its mixtures are presented and discussed for different electrode configurations and distances, gas pressure and service voltage stresses (AC, LI,SI). A comparison of the main chemical and physical properties and the biodegradability of the ester-base oils and a naftenic oil and their compatibiltity, measured in CESI laboratories, is shown with the results of discharge tests on pressboard in each oil. At last the polymeric compound and the most suitable geometry for a MV switchgear enclosure is produced. PUBBLICATO A5012605 (PAD – 625986)PUBBLICATO A5059332 (PAD – 745099)