Study on criterion for quench detection/protection of superconducting magnet based on active power method

Abstract When a quench occurs in a superconducting magnet, excessive joule heating in normal region may damage the magnet. It is important to detect the quench in the magnet as soon as possible and discharge magnetic energy stored in the magnet. The authors have proposed a quench detection/protection system based on active power method which detects an active power dissipated in the magnet after the quench. In this paper, the authors propose a method to decide an appropriate criterion to protect the magnet from the excessive joule heating by using 1D heat equation. The method can determine a safe criterion for the quench detection/protection within a short time. The authors show the usefulness of the method through experimental results for high temperature superconducting coils.