Redundant 3-Phase Superconducting Cable Switching for Fault Isolation
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Solution Overview
Problem
3-phase superconducting cable systems face operational disruptions due to damage, as repairs are time-consuming or impossible, requiring entire system shutdown when any conductor or cryogenic envelope is damaged.
Innovation Solution
A 3-phase superconducting cable system comprising four 1-phase cables with interrupting and connecting switches, shut-off valves, and a coolant routing system allows for selective disconnection and rerouting of coolant, enabling continuous operation by replacing damaged cables and maintaining low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a 3-phase superconducting cable system uses three 1-phase cables, then the system structure is simple and cost-effective, but the entire system must be shut down when any conductor or cryogenic envelope is damaged
Solution Approach 1:
The system is segmented into four independent 1-phase cable units instead of three, allowing individual isolation and replacement of damaged cables while maintaining operation of the remaining cables. Each cable has its own interrupting switches and connecting switches that enable independent control.
Solution Approach 2:
A fourth spare cable is pre-installed in the system alongside the three operational cables. This preliminary preparation ensures that when damage occurs, replacement can happen quickly by switching to the pre-positioned spare cable without needing to source and install a new cable from outside the system.
2Reliability
If interrupting switches and connecting switches are added to enable cable replacement, then system reliability improves, but device complexity increases
Solution Approach 1:
The switching system is segmented into distinct interrupting switches at each cable end and connecting switches that route current between cables. This modular switching architecture allows for controlled isolation and reconfiguration without requiring complex centralized switching mechanisms.
Solution Approach 2:
The connecting switches act as intermediaries that temporarily route current through the fourth spare cable during transition periods. This intermediary switching mechanism enables seamless transfer of load from damaged cables to the spare cable without interrupting overall system operation.
3Reliability
If four 1-phase cables are used instead of three, then redundancy and operational continuity are improved, but the quantity of materials and system cost increase
Solution Approach 1:
The system changes the operational parameter from three active cables to four cables where one remains in standby mode. This parameter change enables fault tolerance while the actual material consumption per operational cable remains the same as traditional three-cable systems, with only the spare cable representing additional material investment.
Solution Approach 2:
The fourth cable is prepared in advance as a spare unit, already installed and connected through the switching mechanism. This preliminary preparation ensures immediate availability for replacement without requiring additional material procurement or installation logistics when faults occur, minimizing the practical impact of the additional material quantity.
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
Enables uninterrupted operation of the superconducting cable system by allowing seamless replacement of damaged cables and maintaining cryogenic conditions, reducing downtime and enabling efficient repair or replacement.
Implementation Method 1
The electrical conductors of both low-temperature and high temperature superconductive cable systems must be cooled during operation in order to establish and maintain their desired superconducting properties
Implementation Method 2
Low-temperature superconductors, typically metallic superconductors, may need to be cooled down to very low temperatures as low as 4 Kelvin or below to become superconducting, which can be achieved, e.g., by using liquid Helium as coolant. High temperature superconductors, typically ceramic superconductors, may need to be cooled down less deep, typically down to temperatures of 77 Kelvin and above, which can be achieved, e.g., using liquid Nitrogen (LN2) as coolant
Data Source
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AI summary
A 3-phase superconducting cable system (100) comprises four 1-phase superconducting cables (A, B, C, D). Interrupting switches (S1, S2, S3, S4, S5, S6) are arranged at respective first and second ends of a first (A), second (B) and third (C) of the 1-phase superconducting cables, and first connecting switches (S7, S9, S11) and second connecting switches (S8, S10, S12) are connected at a first and a second end, respectively, of the fourth (D) 1-phase superconducting cable. The interrupting switches (S1, S2, S3, S4, S5, S6) and the first (S7, S9, S11) and second (S8, S10, S12) connecting switches are operable to selectively disconnect one of the first (A), second (B) and third (C) one of the 1-phase superconducting cables from their respective current phase (L1, L2, L3) and to connect the fourth (D) 1-phase superconducting cable to the previously disconnected current phase (L1, L2, L3), effectively replacing the disconnected 1-phase superconducting cable.