Reliability improvement on underground distribution spot network system

Underground network systems reliability is higher than overhead distribution networks but improvements can be made by the implementation of enhanced topologies and new technologies including high-speed communication, submersible switchgear and protection schemes with digital relays. This paper presents the underground distribution system of AES Eletropaulo (largest electricity distribution company in Latin America) and the solutions that were implemented to improve reliability. Methods to reduce the time of circuit restoration will be shown, including practical results. At the end, the next steps will be presented.