Electrothermal Phenomena About Current Limitation With Coated Conductors

The superconducting (SC) fault current limiter (FCL) is very attractive to enhance the security and the power quality of the electricity grid, so its great interest throughout the world. Most of SC FCL uses the quench of a SC element and the thermal phenomena are fundamental. We study them with two approaches: experiments and calculations. For the experiments, we have developed temperature sensors deposited directly on coated conductors to achieve the best thermal coupling and a very short time response. The sensors are micron size copper meanders. A very thin polymer layer provides the electrical isolation. The sensor performances are very satisfying both in terms of time response and accuracy. The measurements are in good agreement with temperature calculations, performed using the current data during limiting experiments. The recovery phase is very important and has been studied using the temperature measurements. The cooling conditions such as bath temperature play an important part for the recovery. Several tests carried out on different samples are presented and analysed. These works are important for a better understanding of the complex phenomena occurring during a limitation and for the design of a conductor suitable for FCL.