No. 1271
	Recent Trend of Material for Transformers and its Application Technologies
	Investigating R&D Committee of Transformer
	Keyword : Electrical Steel, Amorphous Alloy, Continuously Transposed Conductor, Ester Oil, Super Conducting Wire
	Transformers are the matured electro-magnetic machines that have long histories over 100years and have been improved step by step. And still, they are required for further improvement and advance from various points of view such as cost saving, energy saving, compactness, transportability and ecology etc. Material innovation is essential for the advance of transformers to meet the above needs, together with sophistication of analytical technique and improvement of construction. From the above background, and absence of papers in which the point of "transformer material" is summarized, the recent trend of the transformer materials have been researched and summarized in this report. For example, in the magnetic materials, Japanese electrical steel and amorphous alloy makers are leading the world, and making efforts to reduce the iron loss ceaselessly. In the conducting material, continuously transposed conductors and self bonded wires are popularized, and they are contributing to the reduction of eddy current loss. In the liquid insulation, several ester oil and silicone oil are developed and applied to the transformers from the view points of ecology and less-flammability. In the solid insulation, heat resistance papers and permittivity-controlled boards are applied. In addition, according to the advance of super conducting wires, development of super conducting transformers are on the way. Today and future, it is expected that material innovation will further bring the advancement of transformers.
	©2007. The Institute of Electrical Engineers of Japan