LN2-40.5/1250A-25 Indoor High Voltage SF6 Circuit Breaker
LN2-40.5 Indoor SF6 Circuit Breaker is a reliable high-voltage switching device designed for 40.5kV three-phase AC power distribution systems. Using SF₆ gas as the insulation and arc-extinguishing medium, it provides excellent breaking performance, stable operation, and long service life. With a compact structure and easy integration into metal-clad switchgear, the LN2-40.5 is widely used in indoor substations, industrial power systems, feeder protection, and capacitor bank switching applications.
Get a QuoteOverview
The LN2-40.5 Indoor High Voltage SF6 Circuit Breaker is developed for 40.5kV, 50Hz three-phase AC power distribution systems. Designed for indoor switchgear applications, it provides reliable switching, protection, and control functions for medium-voltage power networks.
Using SF6 gas (Sulfur Hexafluoride) as both the insulation and arc-extinguishing medium, the LN2-40.5 offers excellent breaking performance, superior dielectric strength, and extended operational service life. Its reliable switching capability makes it suitable for applications involving frequent operations, capacitor bank switching, and feeder circuit protection.
The LN2-40.5 SF6 Circuit Breaker is widely applied in industrial facilities, power generation plants, indoor substations, and commercial power distribution systems, providing a dependable solution for modern medium-voltage electrical networks.
Operating Conditions
1. Ambient Temperature: -10°C to +40°C;
2. Maximum Installation Altitude: ≤3000 m;
3. Relative Humidity: ≤90% (at 20°C);
4. Installation Environment: Free from fire hazards, explosive gases, severe pollution, chemical corrosion, and excessive vibration.
Features
Reliable SF6 Arc-Extinguishing Performance
The LN2-40.5 SF6 Circuit Breaker uses SF6 gas as both the insulation and arc-extinguishing medium, ensuring reliable switching performance and effective protection for medium-voltage power systems.
Key advantages include:
- High dielectric strength
- Stable arc interruption performance
- No restrike during switching operations
- Reliable capacitor bank switching capability
- Suitable for frequent switching applications
The optimized arc-extinguishing chamber design improves interruption reliability and ensures stable protection performance under both normal operating conditions and system fault scenarios.
Compact Indoor Switchgear Integration
The LN2-40.5 adopts a compact structure specially developed for installation in 40.5kV metal-clad switchgear systems.
Main benefits include:
- Space-efficient design
- Simplified installation process
- Convenient maintenance access
- Compatible with both withdrawable and fixed switchgear configurations
- Lightweight and practical construction
Two Operating Mechanism Options
CT10-A Spring Operating Mechanism
- Fast energy storage
- Low operating power consumption
- Ideal for automated substations
- Mechanical life up to 6,000 operations
CD10ⅢG Electromagnetic Operating Mechanism
- Simple and robust structure
- Cost-effective solution
- Suitable for conventional substations
- Mechanical life up to 5,000 operations
Excellent SF6 Gas Sealing Reliability
The LN2-40.5 SF6 Circuit Breaker features a fully sealed SF6 gas chamber, ensuring stable insulation performance and reliable long-term operation.
Key features include:
- Rated SF6 gas pressure: 0.65 MPa
- Annual gas leakage rate ≤ 1%
- Integrated SF₆ gas density monitoring system
- Stable dielectric insulation performance
- Reduced maintenance requirements
The built-in gas density monitoring device continuously monitors SF6 pressure conditions, helping maintain safe and reliable breaker operation throughout its service life.
Extended Electrical and Mechanical Endurance
Designed for demanding medium-voltage switching applications, the LN2-40.5 Indoor SF6 Circuit Breaker provides excellent electrical and mechanical durability.
Performance parameters include:
- Rated current switching operations: 2,000 operations
- Rated short-circuit breaking operations: 16 operations
- Spring operating mechanism mechanical endurance: 6,000 operations
- Electromagnetic operating mechanism mechanical endurance: 5,000 operations
With reliable switching performance and long service life, the LN2-40.5 is well suited for utility networks, industrial power systems, and applications requiring stable long-term operation.
Technical Data
Electrical Ratings
| Item | Unit | Parameter |
| Rated Voltage | kV | 40.5 |
| Rated Current | A | 1250 |
| Rated Frequence | Hz | 50 |
| Lightning Impulse Withstand Voltage | kV | 185 |
| Power Frequency Withstand Voltage (1 min) | 95 | |
| Rated Short-Circuit Breaking Current | kA | 25 |
| Rated Short-Circuit Making Current (Peak) | 63 | |
| Rated Peak Withstand Current | 63 | |
| Rated 4s Short-Time Withstand Current | 25 | |
| First-Pole-to-Clear Factor | / | 1.5 |
| Capacitor Bank Switching Current | A | 400 |
| Rated operating sequence | / | O–0.3s–CO–180s–CO |
| Out-of-Phase Breaking Current | kA | 6.3 |
| Rated Current Breaking Operations | / | 2000 |
| Short-Circuit Breaking Operations | / | 16 |
Operating Performance
| Mechanism | Closing Time | Opening Time (Minimum Voltage) | Opening Time (Rated Voltage) |
| CT10-A Spring | ≤0.15 s | ≤0.10 s | ≤0.07 s |
| CD10ⅢG Electromagnetic | ≤0.20 s | ≤0.10 s | ≤0.07 s |
SF6 Gas Parameters
| Item | Specification |
| Rated Gas Pressure (20°C) | 0.65 MPa |
| Alarm Pressure | 0.42 MPa |
| Lockout Pressure | 0.40 MPa |
| Annual Leakage Rate | ≤1% |
| Moisture Content | ≤150 ppm (V/V) |
| SF6 Gas Quantity | 1.5 kg |
Control Voltage Options
CT10-A Spring Mechanism
- Closing Coil: DC48V / DC110V / DC220V
- Trip Coil: DC48V / DC110V / DC220V
- Energy Storage Motor: DC110V / DC220V
CD10ⅢG Electromagnetic Mechanism
- Closing Coil: DC110V / DC220V
- Trip Coil: DC48V / DC110V / DC220V
Overall and mounting dimensions(mm)
Physical Data
| Item | Specification |
| Breaker Weight | 135 kg |
| SF₆ Gas Weight | 1.5 kg |
Installation Features
The LN2-40.5 Indoor SF6 Circuit Breaker is designed as a three-phase integrated indoor breaker for installation in standard 40.5kV metal-clad switchgear, supporting both withdrawable and fixed switchgear configurations.
Main installation advantages include:
- Compact and space-saving structure
- Standardized mounting dimensions
- Lightweight design for easier handling
- No requirement for heavy concrete foundations
- Simplified installation and commissioning process
Typical Applications
The LN2-40.5 SF6 Circuit Breaker is widely applied in various medium-voltage power distribution systems, including:
- Indoor substations
- Power generation facilities
- Industrial and mining plants
- Commercial power distribution networks
- Utility distribution substations
- Capacitor bank switching applications
- Feeder protection systems
- Frequently operated switching applications
With reliable SF6 insulation technology and a compact switchgear-mounted structure, the LN2-40.5 provides a practical solution for modern medium-voltage power systems.
Why Choose the LN2-40.5 SF6 Circuit Breaker?
The LN2-40.5 combines reliable performance, compact design, and flexible configuration for demanding power distribution applications.
Key advantages include:
- Reliable 40.5kV indoor SF₆ circuit breaker solution
- Excellent insulation capability and arc-extinguishing performance
- Compact design for metal-clad switchgear integration
- Available with spring or electromagnetic operating mechanisms
- Low annual SF₆ leakage rate (≤1%)
- Long electrical and mechanical service life
- Suitable for frequent switching and capacitor bank applications
- Easy installation with reduced maintenance requirements
- Designed for stable operation in demanding medium-voltage distribution environments
Customization Services
We provide flexible customization options to meet different utility, industrial, and EPC project requirements, including:
- Various rated current configurations
- Customized auxiliary and control voltage options
- Spring or electromagnetic operating mechanism selection
- OEM branding and private label services
- Technical drawings and Factory Acceptance Testing (FAT)
- Project-specific engineering support
Contact us for quotations, technical documents, and customized solutions for 40.5kV indoor SF6 circuit breaker applications.
