Detailed Introduction to Richge Technology SF6 Circuit Breaker

    Richge Technology mainly focuses on the manufacturing of low-voltage switchgear accessories, high-voltage switchgear components, and indoor/outdoor circuit breaker series. The following provides a professional introduction to SF6 circuit breakers for reference.

I. Basic Overview of SF6 Circuit Breaker

    SF6 circuit breaker is a high-voltage circuit breaker that uses sulfur hexafluoride (SF6) gas as insulation and arc-extinguishing medium, widely used in the transmission and distribution fields of power systems.

Core Features:

• Excellent insulation performance: The insulation strength of SF6 gas is 2.5-3 times that of air, which can significantly reduce the equipment volume.

• Superior arc-extinguishing capacity: High arc column conductivity, short arc time (2-2.5 cycles), and large breaking capacity (up to 80kA).

• No fire risk: SF6 gas is non-flammable with high safety.

• Long service life: Electrical life can reach more than 25 years, with long maintenance cycle and reduced maintenance frequency.

II. Working Principle and Structure

2.1 Working Principle

Arc-extinguishing Mechanism:

1. During opening, the moving and static contacts separate to generate an arc, which causes SF6 gas to decompose into S, F atoms and positive/negative ions at high temperature.

2. SF6 gas molecules capture free electrons to form negative ions, reducing the conductivity of the arc column and accelerating arc extinction.

3. After the arc is extinguished, the gas restores its original insulation state.

Gas Circulation: Adopting pressure gas type or self-energy type principle, gas flow is generated through piston or arc energy to quickly extinguish the arc and restore insulation.

2.2 Main Structure

III. Types and Technical Parameters of SF6 Circuit Breakers Produced by Richge Technology

3.1 Main Types

1. Classified by structure:

• Porcelain column type: Three-phase independent, large volume, suitable for outdoor places (such as FA4-550 type)

• Tank type (floor tank type): Three-phase common tank, compact structure, good seismic performance, easy maintenance

• Circuit breaker in GIS combined electrical equipment: Integrated with disconnector, grounding switch, etc. in a sealed shell

2. Classified by arc-extinguishing method:

• Single-pressure type: Only one pressure inside the arc extinguishing chamber, simple structure, widely used

• Dual-pressure type: With high and low pressure air chambers, better arc-extinguishing performance but complex structure

3.2 Key Technical Parameters

IV. Advantages and Application Scenarios of SF6 Circuit Breaker

4.1 Product Advantages

1. Excellent breaking performance: Can quickly extinguish arcs, hardly generate chopping overvoltage, and protect equipment and lines

2. High reliability: Sealed structure reduces the impact of external environment, suitable for various harsh climate conditions

3. Low noise: Operation noise is less than 85dB, improving working environment

4. Small floor area: Compact structure, especially suitable for urban substations and space-constrained places

5. High intelligence level: Can integrate monitoring system to real-time monitor gas density, temperature and operation status

4.2 Application Scenarios

• Power transmission system: Protection and control of 500kV and above ultra-high voltage transmission lines

• Substation: Used as protection equipment for main transformers and busbars

• Industrial power grid: High-voltage power distribution for self-provided power stations in large factories, mines, etc.

• New energy grid connection: Protection equipment for booster stations in wind farms and photovoltaic power stations

• Urban power grid: Core component of compact GIS switchgear

V. Installation and Maintenance Points

5.1 Installation Requirements

1. Foundation preparation:

• Levelness error <1mm/m to ensure equipment stability

• Perfect grounding system, grounding resistance <0.5Ω

2. Gas treatment:

• Gas leakage detection before installation, annual leakage rate should be <1‰

• Evacuate to below 133Pa and keep for more than 2 hours, then fill with qualified SF6 gas after confirming no leakage

• Gas filling pressure strictly follows product manual requirements, error controlled within ±0.02MPa

3. Mechanism adjustment:

• Opening and closing time and synchronization adjustment meet technical requirements

• Operating mechanism is flexible without jamming

• Auxiliary switch switches accurately with normal signal feedback

5.2 Maintenance Methods

Regular inspection items:

Special maintenance:

• Gas replenishment: When the pressure drops to the alarm value (usually 0.05MPa lower than the rated pressure), timely replenish gas

• Gas replacement: After breaking severe fault current, check gas quality and replace if necessary

• Density relay calibration: Conduct calibration every 2-3 years

VI. Precautions and Safety Measures

1. SF6 gas characteristics:

• Pure SF6 is non-toxic, but arc decomposition products (such as SO2, HF) are toxic, so ventilation is necessary during maintenance

• Avoid gas contact with skin and respiratory tract, wear protective equipment if necessary

2. Maintenance safety:

• Must first cut off power, verify no electricity and ground before maintenance

• Reduce the pressure to zero gauge pressure before releasing SF6 gas

• Forced ventilation for more than 15 minutes after opening the equipment to ensure internal gas is exhausted

3. Environmental protection requirements:

• SF6 is a strong greenhouse gas (GWP value 23900), so emissions should be strictly controlled

• Waste gas must be recycled and treated, and must not be directly discharged into the atmosphere

VII. Summary

    With its excellent insulation and arc-extinguishing performance, SF6 circuit breaker has become the mainstream choice of high-voltage switchgear in modern power systems, especially suitable for large-capacity, high-voltage level power transmission and distribution scenarios.

About Richge Technology:

• The company mainly produces low-voltage switchgear accessories (such as main circuit connectors, auxiliary circuit connectors, operating mechanisms, etc.), high-voltage switchgear components (such as insulation parts, grounding switches, interlocking mechanisms, etc.) and indoor/outdoor circuit breaker series.

• To learn about Richge's complete product line, it is recommended to visit its official website (www.richgeswitchgear.com) or contact its sales department (WhatsAPP: +86 189 5893 8078)