Nested Thomson Coil Actuator for Faster Hybrid Breaker Opening
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Solution Overview
Problem
Existing circuit interrupters, such as hybrid circuit breakers, face limitations in opening mechanical separable contacts at high speeds, leading to potential let-through current due to the slow actuation of actuators between fault detection and contact separation.
Innovation Solution
A dual conductor Thomson coil actuator is introduced, comprising two nested conductors wound to form a single coil, each excited by a capacitor bank with half the capacitance of a single conductor coil, allowing for simultaneous charging to the same voltage, resulting in a greater initial pulse of current and magnetic force, enabling faster actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single conductor coil is used in the actuator, then the device complexity is lower, but the opening speed of mechanical separable contacts is insufficient
Solution Approach 1:
The single conductor coil is segmented into two nested conductors wound in opposite directions. Each conductor is independently excited by a separate capacitor bank, allowing the magnetic forces to be optimized for faster contact opening while maintaining manageable complexity through modular segmentation of the coil structure.
Solution Approach 2:
The two conductors are nested within each other, with one conductor positioned inside the other, forming a compact dual-conductor coil structure. This nesting arrangement increases the magnetic force density and opening speed without proportionally increasing the overall device volume or complexity.
2Force
If the capacitance of capacitor banks is increased to provide more current, then the magnetic force increases, but the device complexity and energy storage requirements increase
Solution Approach 1:
The total capacitance requirement is segmented into two separate capacitor banks, each with half the capacitance of a single large bank. This segmentation allows the same total energy to be stored with smaller, more manageable capacitor units, reducing individual component stress and simplifying the overall energy storage architecture.
Solution Approach 2:
The system changes the electrical parameters by using two capacitor banks at the same voltage but with half the capacitance each, compared to one large capacitor bank. This parameter transformation maintains the total energy (E=1/2CV²) while altering the distribution, enabling higher peak current delivery through the dual conductor configuration.
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 dual conductor Thomson coil actuator significantly reduces the time to open mechanical separable contacts, minimizing let-through current and improving the speed of fault current interruption compared to traditional single conductor actuators.
Implementation Method 1
Thomson coil actuators are noted for their ability to open mechanical separable contacts very high speeds
Implementation Method 2
the initial pulse of aggregate current through the dual conductor coil is greater than the initial pulse of current through the single conductor coil, which results in the aggregate magnetic force exerted by the two nested conductors
Data Source
AI summary
A dual conductor Thomson coil actuator for use in opening the separable contacts of a circuit interrupter comprises two nested conductors wound to form a single coil, rather than the traditional design comprising one single conductor wound to form a coil of the same size. Each of the two conductors can be excited by half the capacitance that would be used to excite the traditional single conductor coil, using the same voltage as the single conductor coil. When the same total capacitor-stored energy that would be used to excite the single conductor coil is instead used to excite the dual conductor coil, the initial pulse of aggregate current through the dual conductor coil is greater than the initial pulse of current through the single conductor coil, resulting in a faster initial opening distance of the separable contacts during an opening stroke.