LW34-40.5 Sulfur Hexafluoride (SF6) Circuit Breaker
LW34-40.5 Sulfur Hexafluoride (SF6) Circuit Breaker is a three-phase AC 50Hz outdoor high-voltage circuit breaker designed for 40.5kV power transmission and distribution systems. It uses SF6 gas as the arc-extinguishing and insulation medium, providing reliable short-circuit interruption, stable electrical performance, and excellent mechanical durability. The circuit breaker is widely applied in substations, industrial power networks, and distribution systems for line switching, transformer protection, and power system safety control.
Get a QuoteOverview
The LW34-40.5 outdoor SF6 circuit breaker is a three-phase AC 50Hz high-voltage switching device designed for 40.5kV power transmission and distribution systems. Utilizing SF6 gas as the arc-extinguishing and insulation medium, it provides reliable control, protection, and fault interruption for electrical networks. The circuit breaker can be used as a grid interconnection switching device and is also suitable for applications requiring capacitor bank switching operations.
Features
High Breaking Capability and Reliable Electrical Performance
The LW34-40.5 SF6 circuit breaker adopts an advanced pressure-blast arc-extinguishing chamber design, providing fast and stable arc interruption with a short arcing time. The rated short-circuit breaking current can reach 40kA, meeting the requirements of medium-voltage and high-voltage power distribution systems with high fault current levels.
The circuit breaker offers excellent electrical endurance. Under rated voltage conditions, it can continuously interrupt short-circuit currents of 31.5kA/40kA up to 21 times without SF6 gas replacement or major maintenance, ensuring long-term reliability and reduced operating costs.
High Mechanical Reliability and Stable Switching Performance
Equipped with a CT14-type spring operating mechanism, the LW34-40.5 provides fast and reliable mechanical operation. The mechanical endurance exceeds 3,000 operations, with certain configurations capable of reaching up to 10,000 operations.
The optimized arc-extinguishing system enables stable performance under frequent switching conditions. During capacitor bank switching operations, the circuit breaker can reliably interrupt 630A capacitor current without restriking, ensuring safe operation and maintaining insulation reliability.
Optimized Structural Design
Flexible Current Transformer Integration
The LW34-40.5 series supports flexible current transformer configurations according to different protection and measurement requirements. Each circuit breaker can be equipped with up to 12 current transformers.
The LW34-40.5 and LW34C-40.5 models support 3–12 built-in current transformers, while the LW34A-40.5 model can be configured with external current transformers. The integrated design provides a compact structure, extended maintenance intervals, and improved system reliability.
Robust Chassis Structure and Corrosion Resistance
The equipment chassis is manufactured using cold-formed steel plates with a U-shaped structure and welded assembly, providing high mechanical strength and excellent rigidity.
A complete surface protection process is applied to enhance waterproof, dustproof, and corrosion-resistant performance. The optimized enclosure design ensures reliable outdoor operation while maintaining a clean and professional appearance.
Flexible Installation and Arrangement Options
The LW34-40.5 offers both indoor and outdoor installation configurations to meet different application requirements.
Each arrangement can be divided into a circuit breaker compartment and a measurement & maintenance compartment. The fixed section integrates components such as isolation contacts, earthing switches, and local control cabinets, while the movable section adopts a trolley-based modular structure for convenient installation, replacement, and maintenance.
The circuit breaker trolley integrates the SF6 circuit breaker, current transformers, and isolation contacts. The measurement and maintenance trolley can integrate voltage transformers, surge arresters, and isolation contacts, providing a flexible modular solution for power system applications.
Convenient Operation and Maintenance
The LW34-40.5 is equipped with an advanced MKZ-type SF6 density indicator. The pointer-type pressure display is designed to minimize the influence of temperature variations, allowing accurate monitoring of SF6 gas status during operation.
This design simplifies routine inspection, improves maintenance efficiency, and helps ensure long-term operating reliability.
Compliance Standards
The LW34-40.5 SF6 circuit breaker complies with the requirements of the Chinese national standard GB1984-89 AC High-Voltage Circuit Breakers and the international standard IEC56 High-Voltage AC Circuit Breakers.
Through comprehensive type testing and factory inspections, the product meets the requirements for electrical performance, mechanical reliability, and operational safety, making it suitable for widely used 40.5kV power transmission and distribution applications.
Technical Data
| Item | Unit | Parameter |
| Rated Voltage | kV | 40.5 |
| Rated Current | A | 1600 / 2000 / 2500 |
| Rated Frequence | Hz | 50 |
| Rated Insulation (1min Power Frequency Withstand Voltage) | kV | 95 |
| Rated Insulation (Rated Lightning Impulse Withstand Voltage) | 185 | |
| Rated Pressure of SF6 Gas | MPa | 0.45 |
| Rated Operating Sequence | / | O-0.3S-CO-180S-CS |
| Rated Weight of Product | kg | 100 |
| Mechanical Lifetime | Time | ≥3000(up to 10,000 for some specifications) |
Overall and mounting dimensions(mm)
