Superconducting Cable Fault Switching Control
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Solution Overview
Problem
The existing superconducting cable systems in power grids face inefficiencies due to continuous operation of normally conducting cable systems in parallel, leading to increased losses and reduced service life, and potential power supply interruptions when switching between cable systems during faults.
Innovation Solution
Implementing a method where the normally conducting cable system is only loaded with charging currents during trouble-free operation, minimizing losses, and using a controlled switching sequence to ensure seamless power supply and extended cable life by switching it on before shutting down the superconducting cable system in case of a fault, with a time delay between signal transmissions to circuit breakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the normal-conducting cable system operates in parallel with the superconducting cable system during trouble-free operation, then reliability is improved through redundancy, but energy losses increase and service life of the normal-conducting cable system decreases
Solution Approach 1:
The control unit is pre-configured with switching sequences that define the exact order of operations for transitioning between cable systems. When a fault is detected, the control unit executes the pre-defined sequence: first closing circuit breakers to connect the normal-conducting cable system, then opening circuit breakers to disconnect the superconducting cable system. This preliminary preparation of switching logic eliminates the need for real-time decision-making during faults, ensuring seamless transition without power interruption while avoiding unnecessary parallel operation losses.
2Loss of energy
If the normal-conducting cable system is switched off during trouble-free operation, then energy losses are reduced, but power supply interruption occurs when the superconducting cable system fails
Solution Approach 1:
The control unit maintains the normal-conducting cable system in a pre-charged state with circuit breakers positioned for immediate connection, rather than completely disconnecting it. This preliminary preparation ensures that the normal-conducting cable system can be activated within milliseconds of a fault detection, eliminating power supply interruptions while minimizing energy losses during normal operation when the system remains electrically isolated but ready for immediate service.
3Reliability
If the normal-conducting cable system remains in parallel operation, then seamless switching during faults is ensured, but the service life of the normal-conducting cable system is shortened
Solution Approach 1:
The system dynamically adjusts the operational state of the normal-conducting cable system based on real-time conditions. During trouble-free operation, the system transitions from a static parallel-operation mode to a dynamic ready-state mode where the normal-conducting cable system is pre-charged but electrically isolated, carrying only minimal charging currents. This dynamic state change allows the system to maintain seamless switching capability while dramatically reducing the stress and energy consumption that would otherwise shorten the normal-conducting cable system's service life.
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
This approach reduces overall transmission system losses, extends the service life of normally conducting cables, and ensures uninterrupted power supply by strategically managing the switching between superconducting and normally conducting cable systems.
Implementation Method 1
At sufficiently low temperatures, where the DC resistance of the conductor is zero, they allow for virtually lossless transmission of electrical energy
Implementation Method 2
The cryostat has at least one thermally insulated tube through which a coolant suitable for operating the superconducting cable, such as liquid helium or liquid nitrogen, flows
Data Source
Figure 1
Figure 2
AI summary
A method for transmitting electrical energy is described in which electric current is transmitted between two electrical installations by means of a superconducting cable system (4). The two ends of the superconducting cable system (4) are each connected to one of the electrical installations in a current-carrying manner. A normal-conducting cable system (5) is arranged parallel to the superconducting cable system (4). The function of the superconducting cable system (4) is monitored by a control unit (10). In normal operation, only one end of the normal-conducting cable system (5) is connected to one of the electrical installations in a current-carrying manner.In the event of a fault in the superconducting cable system (4), a first signal (12) from the control unit (10) connects the other end of the normal-conducting cable system (5) to the other electrical system, so that the normal-conducting cable system (5) becomes current-carrying, and the superconducting cable system (4) is subsequently switched off by at least one of the electrical systems by a second signal (11) from the control unit (10).