Superconducting Fault Current Limiter Radial Heat Dissipation
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Solution Overview
Problem
Superconducting fault current limiters require a prolonged cooldown time after a fault, leading to extended outage periods in electric power distribution systems due to slow heat dissipation from the superconductor.
Innovation Solution
A superconducting fault current limiter with a cryostatic cooling system and heat dissipation elements, featuring an electrically insulating coating, that enhances thermal diffusivity and reduces cooldown time by increasing the thermal surface area, thereby minimizing the size and weight of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the superconductor is operated below critical temperature to maintain superconducting state, then low impedance is achieved during normal operation, but cool down time after fault is excessively long
Solution Approach 1:
The patent introduces heat dissipation elements that extend in the radial dimension from the superconducting wire, transforming the heat dissipation path from primarily longitudinal to include significant radial component. This dimensional change dramatically increases the effective heat dissipation surface area, enabling faster thermal energy removal from the superconductor after quench events.
Solution Approach 2:
The heat dissipation elements act as thermal intermediaries between the superconducting wire and the cooling medium. These elements conduct heat away from the superconductor surface and transfer it to the surrounding cooling medium, accelerating the cool-down process without requiring direct contact between the superconductor and the cooling medium throughout its entire surface.
2Productivity
If heat dissipation elements are added to increase thermal surface area, then cool down rate is improved, but device complexity increases
Solution Approach 1:
The heat dissipation elements are strategically positioned at specific locations along the superconducting wire where thermal energy accumulation is most problematic. Rather than uniformly distributing complexity throughout the device, the solution applies thermal management features locally where they are most needed, optimizing cool-down performance while minimizing overall structural complexity.
Solution Approach 2:
The heat dissipation elements are constructed from composite structures combining highly thermally conductive materials for heat transfer with electrically insulating coatings for electrical isolation. This composite approach enables simultaneous achievement of high thermal conductivity for rapid cooling and electrical insulation for safety, without requiring separate complex systems for each function.
3Temperature
If heat dissipation elements are positioned close to superconducting wire, then thermal diffusivity is improved, but short circuit risk increases
Solution Approach 1:
The heat dissipation elements utilize composite construction with an inner core of high thermal conductivity material for efficient heat extraction, coated with an outer layer of electrically insulating material. This composite structure enables the element to achieve both high thermal diffusivity for rapid cooling and sufficient electrical insulation to prevent short circuits, even when positioned close to the superconducting wire.
Solution Approach 2:
The insulating coating on the heat dissipation elements has thickness and material properties specifically selected to provide adequate electrical insulation while maintaining acceptable thermal performance. By carefully controlling the parameters of the coating (material type, thickness, thermal conductivity), the design achieves optimal balance between electrical safety and thermal efficiency.
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 solution enables faster heat dissipation and reduced cooldown time, minimizing outage periods and preventing short circuits through balanced thermal and electrical insulation, allowing for quicker resumption of normal operation.
Implementation Method 1
the heat dissipation elements transfer heat from the superconducting wire into the cooling medium
Implementation Method 2
the heat dissipation elements transfer heat from the superconducting wire into the cooling medium
Implementation Method 3
a superconducting wire immersed in the cooling medium and configured to carry a current, the superconducting wire becoming non-superconducting above a critical current density
Implementation Method 4
the heat dissipation elements have an electrically insulating coating, and whereby the heat dissipation elements transfer heat from the superconducting wire into the cooling medium
Data Source
AI summary
A superconducting fault current limiter (10) is shown. It comprises a cryostatic cooling system (20) for containing a cooling medium (26), a superconducting wire (30) immersed in the cooling medium (26) and configured to carry a current, the superconducting wire (30) becoming non-superconducting above a critical current density, and a plurality of heat dissipation elements spaced along and projecting from the superconducting wire (30), wherein the heat dissipation elements have an electrically insulating coating, and whereby the heat dissipation elements transfer heat from the superconducting wire (30) into the cooling medium (26).