Superconducting Busbar Inductor Layout for Fault Current Limiting
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Solution Overview
Problem
Existing current limiting devices in electrical circuits, particularly in cryogenic systems, face inefficiencies in managing fault currents due to resistive or inductive structures that either increase resistance or impedance, leading to suboptimal performance in both normal and fault conditions.
Innovation Solution
A superconductor current limiting device with a leak-tight enclosure for cryogenic fluid circulation, featuring a superconductor busbar and an inductor with poles connected to terminal parts, which utilizes inductance and resistance to effectively limit fault currents while maintaining efficient current supply in the absence of faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistive structure is used to limit fault current, then the resistance increases with current, but this produces an effect contrary to current limitation
Solution Approach 1:
The invention changes the electrical state of the busbar from normal conducting state to fault state by introducing an inductor that modifies the circuit parameters during fault conditions. The inductor creates a high impedance path that limits fault current without relying on resistive heating, thus avoiding excessive Joules losses while achieving current limitation.
Solution Approach 2:
The inductor acts as an intermediary element between the power supply and the fault. It introduces a magnetic field-based impedance that limits fault current independently of the busbar's resistive properties, resolving the contradiction between current limitation and energy loss by mediating the fault current through a non-resistive mechanism.
2Reliability
If an inductive structure is used to limit fault current, then the impedance increases, but this leads to suboptimal performance in both normal and fault conditions
Solution Approach 1:
The inductor is positioned locally at the beginning of the busbar, creating a localized impedance effect only where needed for fault limitation. The rest of the busbar maintains its optimal conducting properties for normal current supply, thus achieving both fault current limitation and maintained productivity in different locations of the same system.
Solution Approach 2:
The electrical circuit is segmented into a fault protection zone (where the inductor is located) and a normal conduction zone (the rest of the busbar). This segmentation allows the inductive impedance to affect only fault currents originating from downstream faults, while normal operating currents flow efficiently through the entire busbar system.
3Loss of energy
If a superconductor busbar is used to reduce Joules losses, then the efficiency increases, but the device complexity increases due to cryogenic cooling requirements
Solution Approach 1:
The invention extracts the fault limitation function from the superconductor busbar itself and places it in a separate inductor component. This allows the superconductor busbar to maintain its simple, efficient structure for normal operation, while the added inductor handles the fault protection function without requiring the busbar to be more complex.
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 device effectively limits fault currents by increasing impedance through the combined effects of inductance and resistance, reducing Joules losses and optimizing the weight-to-power ratio in cryogenic systems, particularly in aircraft applications.
Implementation Method 1
a superconductor busbar passing through the leak-tight enclosure... in a power electrical circuit cooled by a cryogenic fluid
Implementation Method 2
an inductor comprising two poles is arranged inside the leak-tight enclosure and is disposed facing the central part of the superconductor busbar
Data Source
AI summary
A superconductor current limiting device comprising a leak-tight enclosure having two apertures arranged to allow a circulation of a cryogenic fluid, a superconductor busbar, and an inductor comprising two poles arranged inside the leak-tight enclosure and disposed facing a central part of the superconductor busbar. Each of the two poles of the inductor is electrically connected to a terminal part of the superconductor busbar via a connection link to one of the two poles.