Thermal stress analysis for the meander-shape YBCO fault current limiter

A thermal stress in a meander-shape YBCO fault current limiter has been calculated numerically. The FEM code combining the thermal stress analysis, temperature analysis and current distribution analysis has been developed. From the comparison between the results of simulation and the measurement results of thermal expansion in a small piece of stainless steel, it has been found that the our code is useful for the estimation of thermal stress. The thermal stress and temperature distribution in the meander-shape YBCO fault current limiter under a normal operating condition have been calculated in two conditions; the critical current density of YBCO degrades at the inside of corner and at the middle part of straight section. In both cases, the thermal stress is concentrated around the inside of corner. In the former case, there is high possibility that YBCO bulk is cracked around the corner because the maximum thermal stress exceeds fracture strength of YBCO. On the contrary, in the latter case, there is high possibility that YBCO bulk burns out around the straight section because the maxim thermal stress in YBCO is lower than the fracture strength at the temperature enough to melt YBCO bulk. (C) 2004 Published by Elsevier B.V.