Oil-free pole-mount transformers: Avoiding oil and copper theft

The development of a dry-type outdoor transformer for pole-mount applications has first been presented at the 2011 CIRED conference [1]. While regular dry-type transformers always need to be protected by an enclosure from the environmental conditions, these dry transformers can replace pole-mounted, oil-filled transformers without the need for an enclosure and are able to withstand sun, rain, snow, pollution, etc. Dry polemount transformers offer several benefits: they are not attractive for theft since they do neither contain oil nor copper and removal of the casted epoxy from conductors is costly. There is further no risk for explosion or fire since the transformer does not contain any inflammable oil. Also leakage or spread of oil is excluded and no soil or water contamination can occur. Extensive testing of the outdoor performance of the transformer has been performed during the last years and was recently finalized. An important number of field installations of pilot units has taken place and a production line for high volumes has been set-up.