Transformers have been designed and widely used to transfer energy, for measurement, protection, electrical isolation, and signal coupling. Much of the basic technology used in current transformers seems mature in its essence. However new challenges has to be enfaced every day tracking new sceneries that demand the highest level of knowledge, or even advanced concepts of transformers together with their components and equipment, expected to play a vital role in the upcoming systems. These International Advanced Research Workshops on transformers have proved to be a well stablished and recognised way to stimulate exchange of practical knowledge and discussion about new trends on transformers.