Overcurrent Protection for Gyrotrons in EAST ECRH System

摘要

In this paper, an overcurrent protection system is designed to ensure thesafety of the gyrotrons in the EAST ECRH system. Two overcurrent protectionsystems were established, a fast one and a slow one. The fast one uses thecurrent transformers as the current sensors. The models of the currenttransformers and the superconducting magnet were built to analyze the effect ofthe environmental magnetic field on the current transformers using FI method.The analysis results show that the magnetic induction at the position near thecurrent transformers must less than 0.002 T, i.e., the current transformersshould be placed at a distance greater than 2.2 meters from the magnet centerto ensure its normal work. The slow one uses the shunt to monitor the currents.An anti-fuse FPGA and a timer is used to realize the signal processing in thefast protection circuit and the slow protection circuit respectively. Theresponse time of the fast protection circuit is less than 100 ns, and theresponse time of the slow protection circuit is less than 31 {\mu}s.