Passive Thomson-Coil Switch Actuation for Fault Current Interruption
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Solution Overview
Problem
The activation speed of Thomson coil systems in switching operations is limited by the delay in detecting fault currents and triggering stored electrical energy, leading to inefficient contact separation in mechanical switches.
Innovation Solution
A passive Thomson coil actuator is triggered by the energy of the fault current itself, utilizing the current change rate (dI/dt) to generate motion in the conductive plate, enabling fast state changes in mechanical switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If external electronic circuitry is used to detect fault current and trigger stored electrical energy, then the Thomson coil system can be controlled, but the activation speed is limited by detection and triggering delays
Solution Approach 1:
The Thomson coil system uses the fault current itself to trigger actuation through direct coupling in series. The current flowing through the mechanical switch also flows through the Thomson coil, eliminating the need for separate detection and triggering circuitry. This self-service approach removes external electronic components and achieves immediate response to fault conditions.
Solution Approach 2:
The patent merges the fault current detection function and the actuation function into a single integrated system. The Thomson coil is electrically connected in series with the mechanical switch, so the same current that indicates a fault also directly drives the actuator. This consolidation eliminates the time delays associated with separate sensing and control circuits.
2Ease of operation
If external electronic circuitry and sensors are used for fault detection, then precise control is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the external electronic circuitry and sensors from the system. By using the fault current directly to drive the Thomson coil through series connection, the design eliminates the need for separate detection circuits, microcontrollers, and sensors, significantly reducing system complexity while maintaining operational precision.
Solution Approach 2:
The system performs both detection and actuation functions through the same current path, making the system self-sufficient. The fault current automatically triggers the Thomson coil without requiring external control systems, simplifying the overall device architecture.
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 system achieves rapid contact separation within 1.5 ms for high current change rates (dI/dt) of 5 kA/ms, combining fast actuation with low on-state resistance and high-speed current breaking capabilities, suitable for fault current interruption.
Implementation Method 1
A current flowing through the coil creates a magnetic field that induces eddy currents into the plate, leading to large repulsive electromagnetic forces that can be used for actuation
Implementation Method 2
A current flowing through the coil creates a magnetic field that induces eddy currents into the plate, leading to large repulsive electromagnetic forces that can be used for actuation
Implementation Method 3
these forces are used to promptly separate contacts of the mechanical switch
Data Source
AI summary
A switch system includes a mechanical switch for switching electrical currents, the mechanical switch operating in one of a closed state and an open state; the system further including an actuator configured to change the state of the mechanical switch, wherein the actuator comprises a Thomson-coil system including a Thomson coil, and wherein the mechanical switch and the Thomson coil are electrically connected in series.