HTS Magnet Quench Protection With Optical Detection and Energy Dump
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing quench protection systems for high-temperature superconducting (HTS) magnets are inadequate, particularly for large magnets used in nuclear fusion reactors, as they struggle to quickly detect quenches and effectively dump stored energy to prevent damage, with conventional methods failing to differentiate between temperature and strain changes and being too slow to prevent catastrophic damage.
Innovation Solution
Implementing a system that uses optical fibers to detect temperature changes in HTS magnets by monitoring backscattered light wavelengths, coupled with a demountable joint and bypass resistance to rapidly dump energy through a bypass resistance when a quench is detected, and integrating a shorted secondary coil for faster energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional quench detection methods are used in HTS magnets, then the system structure is simple, but the detection speed is too slow to prevent catastrophic damage
Solution Approach 1:
The patent replaces conventional electrical sensing methods with optical fiber-based detection. Optical fibers monitor temperature changes through backscattered light wavelength shifts, providing rapid quench detection without the complexity of electrical connections in the cryogenic environment. This substitution enables fast detection while maintaining system simplicity.
Solution Approach 2:
The patent introduces optical fibers as intermediary sensing elements that thermally couple to the HTS cable but remain electrically isolated. These intermediaries transfer temperature information from the cryogenic magnet environment to the external detection system, enabling rapid quench detection without direct electrical penetration into the magnet.
2Measurement precision
If optical fiber temperature monitoring is implemented, then quench detection accuracy is improved, but the system complexity increases
Solution Approach 1:
The patent replaces complex electrical temperature sensing and measurement systems with optical fiber-based detection. The optical fibers use intrinsic optical properties (backscattered light wavelength shifts) to measure temperature, eliminating the need for electrical connections, cold electronics, and complex signal conditioning in the cryogenic environment.
Solution Approach 2:
The optical fibers perform self-diagnosis through Brillouin or Raman scattering effects, where the backscattered light wavelength naturally shifts in response to temperature changes. This self-service mechanism provides precise temperature measurement without requiring external power or complex processing at the sensing location.
3Speed
If demountable joints with bypass resistance are used, then energy dumping speed is improved, but the magnet structure complexity increases
Solution Approach 1:
The patent segments the continuous HTS cable into multiple sections connected by demountable joints. Each joint incorporates a bypass resistance that can be selectively engaged to create controlled quench paths. This segmentation enables localized energy dumping without requiring complete magnet disassembly or complex external dump circuits.
Solution Approach 2:
The demountable joints provide dynamic control over current paths during quench events. The joints can transition from a low-resistance superconducting connection to a high-resistance bypass path, enabling adaptive energy management. This dynamic capability allows rapid energy dumping while maintaining operational flexibility.
4Loss of energy
If shorted secondary coils are integrated, then energy dissipation effectiveness is improved, but the device complexity increases
Solution Approach 1:
The patent merges the secondary coil function with existing magnet components such as the cryostat structure or support framework. By integrating the shorted secondary coil into the magnet's structural elements, the patent achieves effective energy dissipation through electromagnetic induction without adding separate, complex coil assemblies.
Solution Approach 2:
The shorted secondary coil serves multiple functions: it acts as a quench protection mechanism, provides structural support, and may serve as a thermal shield. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall device complexity while improving energy dissipation effectiveness.
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 enables rapid detection and effective energy dumping, minimizing damage to HTS magnets by differentiating between strain and temperature changes, and ensuring energy is safely dissipated before significant damage occurs, suitable for large-scale applications like nuclear fusion reactors.
Implementation Method 1
monitoring backscattered light from each of the optical fibres; comparing changes in wavelength of backscattered light from each optical fibre; detecting a change in temperature of a cable of the coil on the basis of a change in wavelength observed in one or more first optical fibres
Implementation Method 2
integrating a shorted secondary coil for faster energy dissipation
Implementation Method 3
a demountable joint and bypass resistance to rapidly dump energy through a bypass resistance when a quench is detected
Data Source
AI summary
A superconducting magnet comprising a field coil comprising high temperature superconducting material and having a joint; a bypass resistance comprising a non-superconducting conductive material, wherein the bypass resistance is electrically connected to the field coil on both sides of the joint; wherein the joint is openable to break the field coil such that current flowing in the superconductor flows though the bypass resistance in order to dump energy from the field coil, and wherein the superconducting magnet is configured to open the joint in response to detection of a quench in the magnet.