Polemount dry-type transformer — Testing and experience

The development of a dry-type transformer for pole mounted application and its major features allowing to use it as an outdoor transformer without need for an enclosure was presented at CIRED 2011 [1]. Meanwhile extensive testing of the outdoor performance of the transformer has continued and field installation of pilot units has taken place. Tests have been performed at both, the demanding KIPTS outdoor test station in South Africa and under controlled harsh conditions of a salt-fog chamber. The applied test conditions are used for proposing typical test procedures for such kind of transformers. Testing with respect to fire behavior was additionally performed.