Interlocked Gas-Insulated Grounding Switch for Overvoltage Faults
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Solution Overview
Problem
Existing vacuum circuit breakers in wind and solar farms face challenges in quickly and effectively managing transient overvoltages during fault conditions, leading to potential damage and inefficiencies due to the use of grounding transformers, which incur significant energy losses and high costs.
Innovation Solution
A compact circuit breaker apparatus with a mechanically interlocked grounding switch and a housing filled with an isolating gas, such as sulfur hexafluoride, allowing the main circuit breaker and grounding switch to be in close, non-longitudinal alignment, reducing arcing and corrosion risks, and enabling rapid fault clearance and grounding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grounding transformer is used to manage transient overvoltages, then overvoltage protection is provided, but significant energy losses and high costs occur
Solution Approach 1:
The patent extracts the grounding function from the traditional grounding transformer and implements it through a dedicated grounding switch with contacts that can be rapidly closed to ground the circuit. This eliminates the continuous energy losses associated with grounding transformers while maintaining overvoltage protection capability.
Solution Approach 2:
The invention uses a simple grounding switch mechanism instead of an expensive grounding transformer. The grounding switch is designed for rapid, temporary operation during fault conditions rather than continuous service, providing cost-effective protection without the ongoing energy consumption of transformer-based solutions.
2Productivity
If vacuum circuit breakers are used for fault interruption, then current breaking capability is achieved, but transient overvoltages cause potential damage
Solution Approach 1:
The patent implements a mechanically interlocked grounding switch that is pre-configured to automatically close when the circuit breaker opens. This preliminary arrangement ensures that grounding action precedes or coincides with fault interruption, preventing transient overvoltages before they can cause damage to equipment.
Solution Approach 2:
The grounding switch serves as an intermediary device between the circuit breaker and the ground. It provides a controlled path for fault currents and transient overvoltages, safely dissipating energy that would otherwise damage the circuit breaker or associated equipment.
3Volume of moving object
If main circuit breaker and grounding switch are placed in close alignment, then compact design is achieved, but arcing risks increase
Solution Approach 1:
The patent fills the housing with sulfur hexafluoride (SF6) gas, an inert atmosphere that suppresses arcing. This allows the main circuit breaker and grounding switch to be positioned in close proximity for a compact design while the SF6 environment prevents harmful arcs from developing between contacts.
Solution Approach 2:
The SF6 gas acts as an intermediary medium between the circuit breaker and grounding switch contacts. It provides dielectric strength to prevent arcing while allowing the components to be closely spaced, effectively mediating between the conflicting requirements of compactness and arc suppression.
4Ease of manufacture
If air-filled housing is used, then manufacturing simplicity is maintained, but corrosion risks increase
Solution Approach 1:
The patent replaces air with sulfur hexafluoride gas in the housing. SF6 is chemically inert and provides excellent corrosion resistance, protecting the internal components from oxidative degradation while maintaining ease of manufacturing through a simple gas-filled seal design.
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 enables immediate and simultaneous fault detection and disconnection, minimizing temporary overvoltages and energy burdens on lightning arrestors, reducing equipment damage, and providing a compact, cost-effective, and corrosion-resistant solution for wind and solar farms.
Implementation Method 1
A compact circuit breaker apparatus with a mechanically interlocked grounding switch and a housing filled with an isolating gas, such as sulfur hexafluoride, allowing the main circuit breaker and grounding switch to be in close, non-longitudinal alignment, reducing arcing and corrosion risks
Implementation Method 2
A vacuum circuit breaker uses the rapid dielectric recovery and high dielectric strength of the vacuum. The pair of contacts are hermetically sealed in the vacuum envelope.
Implementation Method 3
When the electrodes are parted, an arc is produced and supported by metallic vapor boiled from the electrodes. Vapor particles expand into the vacuum and condense on solid surfaces. At a natural current zero, the vapor particles disappear and the arc is extinguished.
Data Source
Figure 1
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Figure 3~4
AI summary
A circuit breaker apparatus (200) has a housing (202), electrical power inlet (214), electrical power outlet, a main circuit breaker (210), a grounding switch (212), and a mechanical linkage (230). The main circuit breaker and the grounding switch each have a pair of contactors therein. The mechanical linkage (230) is movable between a pair of positions in which one of the positions causes the pair of contactors of the main circuit breaker (210) to close and the pair of contactors of the grounding switch (212) to open and another position in which the pair of contactors of the main circuit breaker (210) are open and such that the pair of contactors of the grounding switch (212) are closed. The housing has an interior (208) that is filled with an isolating gas.