Quench Detection via Differential Relay and Search Coils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing quench detection systems for superconducting fault current limiters lack simplicity and reliability, particularly in terms of response time, which is critical for interrupting current flow within tens of milliseconds to prevent overheating and damage.
Innovation Solution
A quench detection system utilizing a differential protection relay and voltage transformers to convert voltage differences across the fault current limiter into proportional current signals, allowing for fast and sensitive detection of quench events and triggering a circuit breaker when the current difference exceeds a predetermined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage difference measurement is used for quench detection, then detection sensitivity is improved, but response time is insufficient due to signal processing delays
Solution Approach 1:
The patent replaces complex signal processing systems with a direct electrodynamic comparison mechanism. Two search coils are positioned to detect magnetic flux changes from the superconductor, and their induced voltages are directly compared through a galvanometer or electronic amplifier, eliminating the need for Fourier transformation or other time-consuming signal analysis methods.
Solution Approach 2:
The patent uses search coils to create electromagnetic copies of the magnetic flux distribution around the superconductor. These coils replicate the flux changes without physical contact, allowing rapid detection of quench events through voltage comparison while avoiding the delays associated with direct measurement and digital processing.
2Measurement precision
If complex signal processing is applied to voltage difference data, then detection accuracy is improved, but system complexity increases
Solution Approach 1:
The patent substitutes complex digital signal processing algorithms with an analog electrodynamic comparison system. The search coils and galvanometer create a direct physical comparison of magnetic flux states, providing accurate quench detection through fundamental electromagnetic principles rather than computational methods.
Solution Approach 2:
The patent changes the detection parameter from processed voltage difference data to direct induced voltage comparison in search coils. By measuring the electromagnetic induction effect directly in real-time, the system achieves accurate quench detection without requiring Fourier transformation or other complex parameter processing.
3Loss of time
If fast quench detection is implemented, then current interruption time is reduced, but detection reliability may be compromised
Solution Approach 1:
The patent replaces software-based detection algorithms with a hardware-based electrodynamic comparison system that operates on fundamental electromagnetic principles. This physical system provides inherently reliable and instantaneous detection of magnetic flux changes, ensuring both speed and reliability in quench detection.
Solution Approach 2:
The search coils automatically detect magnetic flux changes through electromagnetic induction without requiring external power or active sensing. The system uses the quench event itself to generate the detection signal, providing reliable self-powered operation that maintains both speed and reliability.
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 rapid and reliable detection of quench events, allowing for immediate interruption of current flow, thereby protecting the fault current limiter and downstream components from damage due to overheating.
Implementation Method 1
a voltage transformer (11, 21) which is connected at least to the fault current limiter (1)... the voltage at the incoming end (1) and the voltage at the outgoing end (2) of a superconductor fault current limiter (1) are converted into a current proportional to the voltage at the corresponding ends
Implementation Method 2
a differential protection relay (13), which calculates the current difference and operates a triggering mechanism of a circuit breaker (2), if the current difference exceeds a predetermined value
Implementation Method 3
Superconductors, especially high-temperature superconductors, are well suited for use in a fault current limiter due to their property to lose superconductivity and transit from the non-resistive superconducting state to a normal state with high electric resistivity when at least one of the critical current (Ic), the critical temperature (Tc) or the critical magnetic field (Hc) of the superconductor material is exceeded
Data Source
Figure 1
AI summary
The present invention relates to a quench detection system for a fault current limiter (1), in particular, a high temperature superconductor fault current limiter, making use of a differential protection relay wherein in fault event the differential protection relay operates a triggering mechanism of a circuit breaker (2), thereby opening the electrical circuit and interrupting power supply to downstream components, and a method for quench detection wherein the magnitude of voltage drop during quench is converted to a current signal being proportional to the voltage and which is monitored by the differential protection relay.