Superconducting generators Sample Clauses

Superconducting generators. Present status 1. NbTi, low temperature superconductor, operated at T = 4.2 K, and with TC = 10 K ( -263 ºC). 2. MgB2 or medium temperature superconductor operated around 10-20 K and with TC = 39 K ( -234 ºC) 3. Second generation (2G) RBa2Cu3O6+x (RBCO), the high temperature superconductor tapes operated around T = 20-50 K and with TC = 93 K ( -180 ºC) Only the NbTi wire is industrially established and used in large quantities for magneto-resonance- image (MRI) scanners, Nuclear Magnetic Resonance (NMR) magnets for research as well as accelerators (CERN). The development stage of the technology is at demonstration of the entire generator at full size. All the components are well developed individually, but a central question is if they can cope with the turbine environment. A generator design has been proposed by GE Global Research and there are no technical issues preventing the construction of the entire generator system. One major concern is the reliability of slip rings transferring the full rated power from a rotating armature, because the superconducting field windings are fixed to the nacelle making a cooling system based on liquid helium heat pipes possible. A second concern is the reliability of the relatively complicated cooling system. The price estimate of the NbTi generator looks quite promising due to the low price of the wire. Superconductivity in MgB2 was discovered in 2001 and the development stage of the technology is at coil demonstration at scales suitable for a wind generator. The MgB2 superconductor wire is now available in long length from a small number of manufacturers. It opens up for the possibility to operate at T = 10-20 K, where NbTi is no longer superconducting and without using liquid helium. MgB2 is not as powerful a superconductor as NbTi and the challenge is to design an economical generator system by taking advantage of a higher operation temperature compared to NbTi. RBCO wires have been developed for about 15 years by a relatively small number of companies. The coated conductor direct drive generator is based on the usage of the high temperature superconductor RBa2Cu3O6+x, which becomes superconducting at T = 93 K for R = Yttrium (Y). This gives the possibility to operate the superconductor at T = 20-40 K and considerable simplifications of the cryostat, torque tube and cooling system are envisioned. There have been several full scale demonstrations of large electrical superconducting machines based on the Bi2Sr2Ca2Cu3...