Product Overview

The LN2-40.5 Indoor High Voltage SF₆ Circuit Breaker is designed for 40.5kV, 50Hz three-phase AC power distribution systems. As an indoor switchgear-mounted circuit breaker, it provides reliable switching, protection, and control for medium-voltage power networks.

Using SF₆ (Sulfur Hexafluoride) as both the insulating and arc-extinguishing medium, the LN2-40.5 delivers outstanding interruption performance, excellent insulation, and long service life. It is particularly suitable for applications requiring frequent switching operations, capacitor bank switching, and feeder protection.

The breaker is widely used in industrial plants, power stations, indoor substations, and commercial power distribution systems.

Available Operating Mechanisms

The LN2-40.5 is available with two operating mechanism options:

CT10-A Spring Operating Mechanism (Recommended)
CD10ⅢG Electromagnetic Operating Mechanism

Users can select the most suitable mechanism according to project requirements and operating frequency.

Operating Conditions

Item	Specification
Ambient Temperature	-10°C to +40°C
Maximum Installation Altitude	≤3000 m
Relative Humidity	≤90% (at 20°C)
Installation Environment	Free from fire hazards, explosive gases, severe pollution, chemical corrosion, and excessive vibration

Key Features

Reliable SF₆ Arc-Extinguishing Technology

The breaker utilizes SF₆ gas for both insulation and arc interruption, providing:

Excellent dielectric strength
Stable interruption performance
No restrike during switching
Reliable capacitor bank switching
Suitable for frequent operation

The optimized arc-quenching chamber ensures dependable protection under both normal and fault conditions.

Compact Indoor Switchgear Design

The LN2-40.5 features a compact structure specifically designed for installation inside 40.5kV metal-clad switchgear.

Advantages include:

Space-saving design
Easy installation
Convenient maintenance
Compatible with withdrawable and fixed switchgear
Lightweight 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 Sealing Performance

The sealed SF₆ gas chamber provides long-term operational reliability.

Features include:

Rated gas pressure: 0.65 MPa
Annual leakage rate ≤ 1%
Built-in gas density monitoring
Stable insulation performance
Low maintenance requirements

The integrated density monitoring device continuously supervises SF₆ gas pressure to ensure safe operation.

Long Electrical & Mechanical Service Life

Designed for demanding switching applications, the breaker offers:

Rated current breaking operations: 2,000
Rated short-circuit breaking operations: 16
Spring mechanism mechanical life: 6,000 operations
Electromagnetic mechanism mechanical life: 5,000 operations

This makes the LN2-40.5 suitable for utilities and industrial facilities requiring reliable long-term performance.

Technical Specifications

Electrical Ratings

Item	Specification
Rated Voltage	40.5 kV
Rated Frequency	50 Hz
Rated Current	1250 A
Lightning Impulse Withstand Voltage	185 kV
Power Frequency Withstand Voltage (1 min)	95 kV
Rated Short-Circuit Breaking Current	25 kA
Rated Short-Circuit Making Current (Peak)	63 kA
Rated Peak Withstand Current	63 kA
Rated Short-Time Withstand Current	25 kA / 4 s
Capacitor Bank Switching Current	400 A
Out-of-Phase Breaking Current	6.3 kA
Operating Sequence	O–0.3s–CO–180s–CO
Rated Current Breaking Operations	2,000
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

Physical Data

Item	Specification
Breaker Weight	135 kg
SF₆ Gas Weight	1.5 kg

Installation Features

The LN2-40.5 is designed as a three-phase integrated indoor circuit breaker for installation in standard 40.5kV metal-clad switchgear, including both withdrawable and fixed-type panels.

Key installation benefits include: