SOLAR CLUB du CERN
"CURIOSITES ENERGETIQUES"
New superconducting transformer is light and compact
Pour plus d'information, veuillez contacter : Michel Philippens NWO
(Netherlands Organization for Scientific Research)
philippens@nwo.nl +31 70
3440784
Researchers from the Technology
Foundation STW and the University of Twente, in cooperation with Smit Transformatoren
and Smit Draad, have developed a prototype coil for a superconducting transformer
which is not only light and compact but also energy-efficient. A keen interest
has already been expressed by several companies.
The coil is made from superconducting wires, insulated
using a newly patented method. Furthermore, together with Smit Transformatoren
the researchers have developed a method to wind coils from the fragile
conductor.
The superconducting wires are manufactured from
a ceramic material BSCCO (pronounced `bisko`). This so-called high-temperature
superconductor only allows current to flow without resistance when the
material is cooled to -196 degrees celcius. The new insulation had to be
able to withstand such low temperatures. Therefore the researchers chose
a polyimide-film.
A silver casing covers the thin filaments of the
superconducting material to prevent them from breaking. Like the tape in
an audio cassette, the superconductor is rectangular in cross-section,
4 mm wide and 0.3 mm thick. A conventional insulating technique with a
coating would make the rectangular conductors unreliable because the coating
on the sharp edges of the conductor would be too thin. As a result of this
sparks could easily jump (discharge) and damage would be caused.
In order to prevent damage, the STW researchers
developed an alternative insulating procedure. Together with Smit Draad
they developed a method in which an insulating layer is folded lengthways
around the superconducting tape. The insulation prevents discharges up
to several kilovolts.
The method has already been implemented at the request
of various companies. For example, the market leader ASC (American Superconductor
Corporation) sells conductors which have been insulated by Smit Draad.
The research group anticipates various applications
for compact and light superconducting devices in which the new superconducting
coils and cables will play a role. The compact construction of the transformers
makes their use in trains attractive. Also the superconducting cables could
guarantee the energy supply to large users such as the computer industry
or compact town centres. The high resistance of the current copper cables
means that too much warmth is released during the transport of electricity.
The STW has signed a contract with Smit Draad for
the use of knowledge obtained from the STW project.
