LW36-40.5 Outdoor High-Voltage Sulfur Hexafluoride (SF6) Circuit Breaker
The LW36-40.5 Outdoor High-Voltage SF6 Circuit Breaker is a reliable switching and protection device designed for 40.5kV (35kV system) three-phase AC power networks. Using SF6 gas as the insulation and arc-extinguishing medium, it provides excellent interruption performance, stable operation, and low energy consumption. With a compact outdoor design, high mechanical reliability, and strong environmental adaptability, the LW36-40.5 is widely used for transmission line protection, transformer switching, grid interconnection, and industrial power distribution applications.
Get a QuoteOverview
The LW36-40.5 Outdoor High Voltage SF6 Circuit Breaker is a three-phase AC 50Hz sulfur hexafluoride (SF6) circuit breaker developed for 40.5kV (35kV system) outdoor power transmission and distribution applications. It is designed to provide reliable control, switching, and protection for modern power networks.
The breaker is suitable for various high-voltage applications, including transmission line protection, transformer protection, and power grid interconnection switching. With excellent interruption capability, stable operating performance, and optimized energy consumption, the LW36-40.5 is especially suitable for distribution systems requiring high reliability and consistent switching performance.
Featuring advanced SF6 insulation and arc-extinguishing technology, the LW36-40.5 provides a dependable solution for outdoor substations, utility distribution networks, and industrial power systems.
Features
Self-Energy Arc Extinguishing Technology for High Efficiency and Low Energy Consumption
The LW36-40.5 SF6 Circuit Breaker adopts an advanced self-energy arc-extinguishing principle. Some models are additionally equipped with an auxiliary pressure-blast structure to further improve interruption performance. The arc-extinguishing energy is mainly generated by the thermal energy released from the arc itself.
During the opening operation, the moving and fixed contacts separate to generate an arc, which heats the SF6 gas inside the interrupter chamber. The heated gas expands rapidly and creates a high-pressure airflow. Assisted by a small mechanical pressure-blast effect, the high-pressure SF6 gas is directed through the nozzle to effectively cool and extinguish the arc when the current reaches zero.
Compared with conventional pressure-blast circuit breaker designs, this technology reduces operating energy consumption by 30%–50%. The spring operating mechanism requires only 800J–1000J energy storage, reducing mechanical load and improving long-term operating efficiency. In addition, the breaker avoids current chopping during low-current interruption, such as unloaded transformer and cable switching, effectively reducing overvoltage risks and improving switching stability.
Excellent Electrical Endurance and Mechanical Reliability
The LW36-40.5 Outdoor SF6 Circuit Breaker provides outstanding electrical durability and reliable mechanical performance for demanding power distribution applications.
Superior Electrical Endurance:
- Under rated voltage conditions, the breaker can interrupt 31.5kA/40kA short-circuit currents 18–21 times without SF6 gas replacement or major maintenance.
- Certain high-performance models support a rated short-circuit breaking current of 50kA, making them suitable for power networks with high fault current requirements.
Long Mechanical Service Life:
- The optimized low-wear self-energy arc-extinguishing structure enables a mechanical endurance of ≥5000 operations.
- The extended service life reduces equipment replacement frequency and lowers overall lifecycle maintenance costs.
Excellent Environmental Adaptability
Designed for reliable outdoor operation, the LW36-40.5 features strong environmental resistance and stable performance under harsh conditions.
Main environmental capabilities include:
- Standard operating temperature range: -30℃ to +40℃
- Customized low-temperature versions available for -40℃ environments
- Wind resistance up to ≤34m/s
- Ice coating resistance up to ≤10mm
- Compatible with GB/T 5582 Pollution Level III–IV requirements
With excellent weather resistance and insulation reliability, the LW36-40.5 is suitable for complex outdoor environments including mountainous areas, high-altitude regions, and industrial pollution zones.
Technical Data
| Item | Unit | Parameter |
| Rated Voltage | kV | 40.5 |
| Rated Current | A | 1600 / 2000 / 2500 |
| Rated Frequence | Hz | 50 |
| Rated Short-Circuit Breaking Current | kA | 31.5/40(some models support 50) |
| Rated Short-Circuit Duration | s | 3 |
| Rated Lightning Impulse Withstand Voltage | kV | 185(to ground) / 215(fracture) |
| Rated 1-Minute Power Frequency Withstand Voltage | 95(to ground) / 110(fracture) | |
| Rated SF6 Gas Pressure (at 20℃, Gauge Pressure) | MPa | 0.4-0.45 |
| Operating Energy (Spring Mechanism) | J | 800-1000 |
| Mechanical Life | Times | ≥5000 |
| Current for Making/Breaking Capacitor Banks | A | 500-630 |
| Annual Gas Leakage Rate | % | ≤0.3 |
Overall and mounting dimensions(mm)
Structural Design and Maintenance Advantages
Compact and Lightweight Construction
The LW36-40.5 Outdoor SF6 Circuit Breaker adopts a three-phase porcelain post-type structure with a lightweight steel-section assembled frame design. Compared with traditional pressure-blast circuit breakers of the same voltage class, the optimized structure reduces overall weight by approximately 10%–15%, lowering transportation costs and foundation load requirements during installation.
The lightweight design makes the breaker especially suitable for installation in areas with challenging transportation and construction conditions, such as mountainous regions and high-altitude areas.
Integrated Current Transformer Configuration
The LW36-40.5 mainly adopts a built-in current transformer (CT) configuration. Depending on project requirements, it can accommodate 3–6 CT units with available accuracy classes including 0.2S, 0.5, and 10P, meeting measurement and protection requirements for power systems.
The integrated CT design simplifies the overall structure, reduces the risk of external component failures, and improves equipment reliability and operational safety.
Convenient Maintenance Design
Reliable SF6 Gas Monitoring System
Selected models are equipped with electronic SF6 density relays, enabling remote real-time monitoring of gas pressure and automatic alarms when abnormal conditions occur. This reduces the need for frequent manual inspections.
Standard models use reliable pointer-type SF6 density gauges, which provide clear readings and maintain accuracy without being affected by temperature variations.
Low Maintenance Requirements
The interrupter chamber features a reliable sealing structure with an annual SF6 leakage rate of ≤0.3%, extending the gas refill interval and improving long-term operating stability.
Key components, including the operating mechanism and main contacts, adopt maintenance-friendly designs. Under normal operating conditions, only periodic visual inspection and pressure verification are required every 1–2 years, significantly reducing maintenance workload and operating costs.
Application Scenarios
Regional Substations
The LW36-40.5 is suitable as the main protection and switching equipment for the 35kV side of 110kV/35kV substations, providing reliable line and transformer protection where stable operation and optimized energy consumption are required.
Plateau and Mountainous Distribution Networks
With its lightweight structure and low operating energy consumption, the breaker is suitable for remote areas with difficult transportation conditions. It is also applicable to distribution networks supporting renewable energy integration, including wind power and photovoltaic projects.
Power Grid Interconnection Lines
The LW36-40.5 provides reliable short-circuit interruption capability for grid interconnection applications requiring stable operation, energy efficiency, and long-term power supply reliability.
Industrial Park Power Distribution
Suitable for industrial distribution systems with high short-circuit levels and demanding environmental conditions, including high-voltage power supply protection in industries such as chemical processing and metallurgy.
Compliance with International Standards
The LW36-40.5 SF6 Circuit Breaker complies with the requirements of the national standard GB1984-2003 AC High-Voltage Circuit Breakers and the international standard IEC 62271-100 High-Voltage AC Circuit Breakers.
The product has successfully passed strict type testing and factory inspection procedures, ensuring that its electrical and mechanical performance meets industry requirements while providing reliable compatibility, operational safety, and long-term service performance for modern power systems.
