A new medium/low voltage transformer for use in rural public distribution networks

This article describes the development of a new pole transformer, designed to be unexplodable in the case of an internal fault, to be better adapted to withstand changing loads and to be compact. Laboratory bench tests led to the choice of the best suited liquid dielectric, silicone, combined with temperature-insensitive aramid fibre. An unusual constructive step was the designing of a tank made of injection-moulded aluminium with a built-in high-current fuse. A series of tests were undertaken by the Laboratoires des Renardieres on a number of transformers with simulated faults of different kinds. The results of these tests were used to check the validity of the original design options.<>