HTS Magnet Quench Detection Using Strain and Magnetic Field Shifts
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Solution Overview
Problem
High temperature superconducting magnet systems face significant damage due to large shifts in magnetic field and strain during quench events in partially and non-insulated coils, particularly in multi-coil systems like toroidal field coil sets for tokamaks, which can lead to uncontrolled quenching and damage.
Innovation Solution
Implementing a quench detection system that monitors strain and magnetic field shifts between coils to identify pre-quench conditions, allowing for timely ramp-down and prevention of damage by comparing sensor readings to expected profiles during normal operation, and activating quench prevention measures when deviations exceed thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quench detection is implemented in HTS magnet systems, then reliability is improved, but device complexity increases
Solution Approach 1:
The detection system is divided into multiple independent sensor units distributed around the magnet system. Each sensor monitors local strain or magnetic field conditions, and the system processes signals from individual sensors to detect quench events. This segmentation allows reliable detection while keeping each sensor unit simple and modular.
Solution Approach 2:
The patent uses strain sensors and magnetic field sensors as intermediary devices that indirectly detect quench conditions. Instead of directly monitoring superconducting state changes, the system uses these intermediary physical quantities (strain and magnetic field) that change predictably during quench events, simplifying the detection mechanism while maintaining reliability.
2Measurement precision
If strain sensors and magnetic field sensors are used to monitor pre-quench conditions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The detection system uses sensors that can serve multiple purposes. Strain sensors not only detect quench conditions but also provide information about mechanical stress distribution in the magnet structure. Magnetic field sensors serve both quench detection and field mapping functions. This multi-functionality improves measurement precision while justifying the added complexity through versatile utility.
Solution Approach 2:
The system continuously monitors strain and magnetic field signals, comparing them against predetermined thresholds. When sensor readings indicate pre-quench conditions (such as abnormal strain accumulation or magnetic field deviations), the system provides feedback to trigger alarm or shutdown sequences. This feedback mechanism enhances detection precision by dynamically adjusting monitoring based on real-time conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively detects pre-quench conditions, enabling safe operation and reducing the risk of damage by allowing for controlled shutdowns and mitigating the impact of quench events in high temperature superconducting magnet systems.
Implementation Method 1
local changes in strain in the field coil
Implementation Method 2
local changes in the magnetic field measured within the field coil
Implementation Method 3
superconducting materials are typically divided into 'high temperature superconductors' (HTS) and 'low temperature superconductors' (LTS)
Implementation Method 4
comparing sensor readings to expected profiles during normal operation, and activating quench prevention measures when deviations exceed thresholds
Data Source
Figure 1~2
Figure 3
AI summary
A method of detecting pre-quench conditions in a superconducting magnet comprising an HTS field coil. The field coil comprises a plurality of turns comprising HTS material and metallic stabilizer; and conductive material connecting the turns such that current can be shared radially between turns via the conductive material. Strain is monitored for the HTS field coil and/or support structures of the HTS field coil. The monitored strain is compared to an expected strain during normal operation of the magnet. In response to the comparison, it is determined whether the field coil is in pre-quench conditions.. A similar method is provided where the magnetic field of the HTS field coil is monitored to detect pre-quench conditions, instead of the strain.