Overcurrent Protection for Gyrotrons in EAST ECRH System

TL;DR

This paper presents a dual overcurrent protection system for gyrotrons in the EAST ECRH system, combining fast and slow circuits with magnetic field analysis to ensure safety and reliability.

Contribution

It introduces a novel dual protection approach with environmental magnetic field analysis to optimize sensor placement and response times.

Findings

Fast protection response time < 100 ns

Slow protection response time < 31 μs

Magnetic field analysis informs sensor placement

Abstract

In this paper, an overcurrent protection system is designed to ensure the safety of the gyrotrons in the EAST ECRH system. Two overcurrent protection systems were established, a fast one and a slow one. The fast one uses the current transformers as the current sensors. The models of the current transformers and the superconducting magnet were built to analyze the effect of the environmental magnetic field on the current transformers using FI method. The analysis results show that the magnetic induction at the position near the current transformers must less than 0.002 T, i.e., the current transformers should be placed at a distance greater than 2.2 meters from the magnet center to 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 the fast protection circuit and the slow protection circuit respectively. The response time of the fast protection circuit is less than 100 ns, and the response time of the slow protection circuit is less than 31 {\mu}s.