The world’s first superconducting transformer has just become operational on Geneva’s local electricity grid. The development is expected to cut the price of electricity for the consumer.
The machine, developed by electrical engineers ABB at Berne in collaboration with the utilities Electricite de France and Services Industriels de GenAve, is a stepdown transformer with a power output of 630kVA.
It is designed to convert high-tension electrical energy transmitted across the grid at 18.7kV down to 420V, the low voltage supply suited to industrial or residential developments.
Superconducting electrical machines are much more efficient at conversion of energy than traditional machines. Much more electricity has to be generated than is actually used, because of the resistance in the copper windings of all electrical machines, as well as other transmission losses.
The idea of using superconductors, says ABB spokesman Michael Robertson is eventually to cut losses to zero.
The windings in these superconducting machines are made from a superconducting alloy which loses resistivity when cooled below a certain transition level. ABB has used a bismuth alloy in its first industrial superconducting device – a fault current limiter installed at the Swiss utility last November. Liquid nitrogen is used to cool superconductors in electrical environments where fire is a hazard.
ABB will monitor the machine’s performance under full grid conditions for two years.