Current Transport Characteristics for REBCO Tape in High Electric Field

The current-electric field ( I-E ) characteristic including high electric fields is a key parameter in the detailed design of power devices such as superconducting rotating machines and superconducting current limiters using REBa ₂ Cu ₃ O _y (REBCO, where RE is a rare element) tapes. However, because the REBCO tape may burn out due to heat generation in standard current-carrying measurements, the measurements have been carried out only up to the electric field range of 1 µV/cm, which is the electric field criterion. In this study, the I-E characteristics of REBCO tapes, including high electric fields, were measured using the pulsed current method. Using two different measurement systems with the pulse width ( τ _p ) of 10 msec and 2 sec, we have successfully obtained the I-E characteristics of REBCO tape over a wide range of five orders of magnitude than the electric field criterion (1 μV/cm to 100 mV/cm). Furthermore, the I-E property of a composite conductor consisting of REBCO tape and a thick copper plate was estimated by combining the experimental results of the I-E property with that of copper and compared with the experimental results. The results showed good agreement between both. The measurement of I-E characteristics over a wide range of the electric field, including high electric fields, would be useful for predicting the characteristics of composite conductors, evaluating their performance, and designing devices.