Double Break Contacts for High Voltage DC Circuit Interruption
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Solution Overview
Problem
High voltage circuit interrupters face challenges in minimizing arc formation and extinguishing arcs, especially in DC applications, where zero voltage crossing is not available, leading to potential safety hazards, contact damage, and reduced operational lifespan due to arc-induced issues and insulant leaks in existing designs.
Innovation Solution
A high voltage DC circuit interrupter with a double break contact configuration, where each contact set is accompanied by an arc extinguisher, and both sets of contacts are actuated simultaneously to split the voltage, reducing arcing and utilizing an overcurrent measurement device to manage contact opening and closing, ensuring arcs are drawn into arc extinguishers for quick suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single break contact configuration is used in high voltage DC circuit interrupters, then the device structure is simpler, but arc formation is more severe and harder to extinguish
Solution Approach 1:
The single break contact is divided into two separate breaks (first break and second break) with corresponding first and second arc extinguishers. This segmentation reduces the voltage across each individual break, making arc extinction easier and more effective in high voltage DC applications where zero voltage crossing is not available.
2Productivity
If contacts are opened under load in high voltage applications, then the circuit can be interrupted, but electric arcs form between separating contacts causing damage and safety hazards
Solution Approach 1:
The arc extinguishers are designed to intentionally capture and contain the harmful arcs within controlled chambers filled with arc-quenching media. This converts the destructive arc energy into a contained phenomenon that can be safely dissipated, protecting the contacts and surrounding components from damage.
3Object-affected harmful factors
If arc extinguishers are added to each contact set in a double break configuration, then arc suppression is improved, but device complexity increases
Solution Approach 1:
The circuit interrupter is segmented into two identical modular units (first break with first arc extinguisher, second break with second arc extinguisher). This modular segmentation allows for effective arc suppression while maintaining a systematic and organized structure that is easier to manufacture and maintain compared to a single complex arc extinguishing system.
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 solution effectively minimizes arc formation and quickly extinguishes arcs, enhancing safety and operational lifespan by reducing arcing across contacts and ensuring reliable operation in high voltage DC applications.
Implementation Method 1
As the contacts separate, an electric arc may be formed in the gap between the contacts. An electrical arc is a plasma discharge between two points that is caused by electrical current that ionizes gasses in the air between the two points.
Implementation Method 2
A first arc extinguisher is provided that draws arcs into the arc extinguisher and extinguishes the arcs
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A high voltage DC circuit interrupter that is provided with a double break contact where each contact is provided with an arc chamber. The double break contacts are provided in series with each other and an overcurrent measurement device such that if an overcurrent is measured, the contacts are simultaneously opened (i.e., double break) to lower the voltage that is developed across each of the sets of contacts. A handle is provided for simultaneously resetting and closing the sets of contacts.