Development of -1MV DC Filter and High-voltage DC Measurement Systems for ITER NBI

Abstract

This paper presents the development results of a -1MV DC filter and DC measurement systems for an ITER neutral beam injector system. High accuracy of 0.5% and fast responsivity of 3.3µs, -3dB are required for the DC measurement systems: both DC voltage dividers and DCCTs. Circuit design and thermal flow design were carried out to clarify and minimize their effects on the accuracy and responsivity. The validity of the established design was demonstrated by the actual-product tests; temperature rise of each components fell below the allowable value; inner components of DC filter withstood DC -1.2MV; each voltage divider accurately measured the voltage during the DC -1.2MV withstand voltage test; the voltage dividers and the DCCTs were adequate to the requirements of responsivity (3.3µs, -3dB).