Evaluation on the operational state of turboexpanders in a helium refrigerator for nuclear fusion experimental devices using principal component analysis

Abstract The operational state of helium turboexpanders has been evaluated using principal component analysis (PCA). For the evaluation, two models which were single and multiple ones were utilized. The single and the multiple models assess a single turboexpander and seven turboexpanders, respectively. In the model development, we used measurement data of helium turboexpanders for a cryogenic system in the Large Helical Device. Using the two models, the changes in the turboexpanders’ condition before and after the occurrence of the trouble were clarified. Consequently, the PCA is very useful to monitor the turboexpanders. Comparing the two models, the single is more practical than the multiple one.