Today, state of the art computer programs have extracted about as much cost as possible in pursuit of competitive transformer designs, while still maintaining the highest standard of quality and reliability. High-temperature in liquid-immersed transformer applications offers a new avenue to explore the possibilities of matching an application with optimized cost and is now one of the few opportunities available for a true step-change in design strategy.
High-temperature design is not really new. It has been around for many years operating on the fringe of the standards and lurking in the background. Since, almost by definition, the standards follow technology rather than lead the development, at some point a critical mass creates the need for a written document, to structure and guide the future development of a new technology.
The time has now come. This presentation will discuss a newly published IEEE document that defines multiple insulation systems and establishes a matrix of thermal classes with corresponding limiting temperatures. IEEE Std C57.154 will finally standardize high-temperature liquid-immersed transformers. The discussion will include the recently published and radically revised IEEE Std C57.100 that defines the procedures for determining the thermal index of an insulation system in a liquid dielectric medium. Preliminary information about one of the first new insulation systems to be thermally characterized by this standard will be presented. And finally, a few examples of typical and not-so-typical global applications for high-temperature liquid-immersed transformers will be presented.
- Liquid immersed transformer insulation systems can now be characterized by thermal class.
- More than one liquid-immersed transformer insulation system thermal class is now defined by IEEE standards.
- Ester liquids and silicone liquids are suitable for high-temperature application.
- High-temperature liquid-immersed transformers can be applied in many common applications.
- A new inexpensive, high-temperature liquid-immersed transformer insulation is now available for use in limited trial applications.
Rick Marek received his BSEE from Purdue University in 1970 and has been employed with DuPont since 1998. His previous work experience includes a total of 28 years with Hevi-Duty Electric, National Industrial and ABB in transformer and specialty power supply manufacturing. He worked as an engineer in design, test and development for special magnetics, dry-type, epoxy cast and liquid-filled transformer products. For 20 of those years he served as a design or engineering manager. He is a senior member of IEEE where he has been active in the Transformers Committee, various subcommittees and numerous working groups since 1982. Rick has served as chairman of the harmonic loading guide, C57.110; the high-temperature liquid-filled transformer standard, PC57.154; and the dry-type loading guide, PC57.96. He is an IEC TC 14 delegate for the US Technical Advisory Group and is active in working groups and maintenance teams related to transformers. He is also the convener of the high-temperature liquid-filled transformer standard IEC 60076-14.