50m-Long High-Tc Superconductor for Power Cables

Self-field AC Power Dissipation in High-Tc Superconducting Tapes and a Prototype Cable

“…The critical current of MF-7 tape was 15.4 A, as shown in Table 1. The dashed and solid lines shown in the graph are given by (7) and (17), respectively, where Q = P/f in (J/m/cycle). It is clear from Figure 3.…”

“…It is interesting to note that the losses predicted by (7) are independent to the aspect ratio, and thus also apply to a circular conductor. Although (7) gives the magnitude of the loss variation with applied current, it cannot be used to predict the instantaneous variation. The instantaneous axil electric field during the descending half of the cycle can be determined by differentiating (4) with respect to time, which gives…”

“…Although the analytical solution of this integral is complex, it can be modelled numerically. Clearly the power dissipation given by (7) and (9) should in principle be equivalent. However, at β = 0.1 for example, the difference between the losses predicted by (7) and 9is found to be approximately an order of magnitude.…”

“…Clearly the power dissipation given by (7) and (9) should in principle be equivalent. However, at β = 0.1 for example, the difference between the losses predicted by (7) and 9is found to be approximately an order of magnitude. This is due to E ↓ (x, t) being restricted to the value at x = a, i.e., the total flux change between the electric center line and the surface of the conductor.…”

“…The significance of these factors on the observed losses and how their influence was minimized for accurate and reproducible measurements is also detailed. There are currently several research groups in the World who are actively involved in AC loss measurements on prototype superconducting cables [1,[7][8][9]. The observed losses in the two layer prototype conductor discussed in this paper are also compared, in addition to theoretical models, with measurements reported by these groups.…”