부산대학교 도서관

The mechanical performance of a SMES model coil was measured by strain gauges, displacement gauges and acoustic emission (AE) sensors attached to the coil surface during an overcharge test. The displacements of the SMES model coil were proportional to the squared currents during charging up until 35.4kA. It was clear that the coil became deformed elastically by the electromagnetic force during overcharging. The test results obtained by the measurement of strains were compared with calculated results obtained by finite element method analysis. As a result of the comparison, good agreement was found in both stresses, and the values were sufficiently small. It was demonstrated that the coil had no problem regarding mechanical performance. It was clarified that AE signals significantly decreased in the current region after repeated excitation. Furthermore, the characteristics of AE signals were different from the coil windings with coil supports. The wave of AE signals in the windings was minimal ms and more than 100kHz, and in the coil support more than 10ms but less than 40kHz.