YBCO coated conductors by an MOD/RABiTS/spl trade/ process

We develop a general theory to account self-consistently for self-field effects upon the average transport critical current density Jc of a flat type-II superconducting strip in the mixed state when the bulk pinning is characterized by a field-dependent depinning critical current density Jp(B), where B is the local magnetic flux density. We first consider the possibility of both bulk and edgepinning contributions but conclude that bulk pinning dominates over geometrical edge-barrier effects in state-of-the-art YBCO films and prototype second-generation coated conductors. We apply our theory using the Kim model, JpK (B) = JpK (0)/(1 + |B|/B0), as an example. We calculate Jc(Ba) as a function of a perpendicular applied magnetic induction Ba and show how Jc(Ba) is related to JpK (B). We find that Jc(Ba) is very nearly equal to JpK (Ba) when Ba ≥ B * a , where B * a is the value of Ba that makes the net flux density zero at the strip's edge. However, Jc(Ba) is suppressed relative to JpK (Ba) at low fields when Ba < B * a , with the largest suppression occurring when B * a /B0 is of order unity or larger.

Section: And the Corresponding Value Of P Issupporting

confidence: 60%

Self-field effects upon the critical current density of flat superconducting strips

Brojeny¹,

Clem²

2005

“…One such technique is metal-organic deposition (MOD), utilised by American Superconductor Corporation. Progress using this technique has been rapid and high values of J c can be achieved in thick films [40,22], despite such films including a number of second phases and porosity. A comprehensive discussion of the progress and challenges involved in optimising such chemical solution deposited coated conductors is found in Holesinger et al [41].…”

Section: Mod On Rabitsmentioning

confidence: 99%

Importance of low-angle grain boundaries in YBa₂Cu₃O_7−δcoated conductors

Durrell¹,

Rutter²

2008

Abstract. Over the past ten years the perception of grain boundaries in YBa 2 Cu 3 O 7−δ conductors has changed greatly. They are no longer a problem to be eliminated but an inevitable and potentially favourable part of the material. This change has arisen as a consequence of new manufacturing techniques which result in excellent grain alignment, reducing the spread of grain boundary misorientation angles. At the same time there is considerable recent evidence which indicates that the variation of properties of grain boundaries with mismatch angle is more complex than a simple exponential decrease in critical current. This is due to the fact that low-angle grain boundaries represent a qualitatively different system to high angle boundaries. The time is therefore right for a targetted review of research into low-angle YBa 2 Cu 3 O 7−δ grain boundaries. This article does not purport to be a comprehensive review of the physics of grain boundaries as found in YBa 2 Cu 3 O 7−δ in general; for a broader overview we would recommend that the reader consult the comprehensive review of Hilgenkamp and Mannhart (Rev. Mod. Phys., 74, 485, 2002). The purpose of this article is to review the origin and properties of the low-angle grain boundaries found in YBa 2 Cu 3 O 7−δ coated conductors both individually and as a collective system.

“…The present technology is limited to a YBCO layer thickness of ≤2 µm, since further increase in thickness is not improving J e (33,38). It should be said that progress with respect to YBCO layer thickness is reported (39) without loss of J c which is highly encouraging.…”

Section: J-b-t Characteristics Of 2g Htsmentioning

confidence: 90%

“…American Superconductor as a primary manufacturer of CC is using the Rolling Assisted Bi-axial Textured Substrates (RABITS) (32,33), 12 Figure 2.5: YBCO Coated Conductor (CC) -Architecture of coated conductor consisting of a metal substrate (light gray), one or more ceramic buffer layers (darker gray) and on top a (RE)Ba 2 Cu 3 O 6 layer (dark gray). Orientation of (RE)Ba 2 Cu 3 O 6 grains is induced by the texture of substrate and buffer layers.…”

Section: Manufacturing Of Ybcomentioning

confidence: 99%

Superconducting wind turbine generators

Abrahamsen¹,

Mijatović

Seiler³

et al. 2010

196

We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200–300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.