Overview

The LW8(A)-40.5 Series High-Voltage AC SF6 Circuit Breakers is a three-phase AC device designed for 50Hz outdoor high-voltage applications, with a rated voltage of 40.5kV. It is suitable for the control and protection of 40.5kV transmission systems, as well as for use in combined breaker and capacitor bank installations.

The product features outstanding breaking performance using a vacuum-sealed chamber. It has short arc-extinguishing times, long service life, and can continuously break 31.5kA short-circuit current 21 times without requiring maintenance or replacing the SF6 gas. Its mechanical reliability is excellent, with a lifespan exceeding 3000 operations and high-frequency switching capabilities. It can accommodate up to 12 CT current transformers, offering flexibility for various applications. The product uses a new MKZ-type SF6 density monitor, ensuring stable pressure readings unaffected by temperature changes for easier maintenance. The circuit breaker complies with GB1984-89 (High Voltage AC Circuit Breakers) and IEC56 standards, ensuring quality and reliability. This model is equipped with the CT14 spring-operated mechanism.

LW16-40.5 is an outdoor SF6 circuit breaker designed for three-phase AC 50Hz systems, with a rated voltage of 40.5kV, used for transmission system control and protection. It is also suitable for combined breaker and capacitor bank installations, with built-in current transformers for monitoring and protection. The LW16-40.5 breaker meets GB1984-1989 and IEC60056 standards, ensuring reliable breaking performance. It features long operational life, short arc-extinguishing time, and the ability to withstand continuous short-circuit currents of 25kA for 20 times without maintenance. The design includes vacuum sealing, ensuring high insulation and excellent performance under extreme conditions.

LW34-40.5 is an outdoor SF6 circuit breaker for three-phase AC 50Hz systems, designed for transmission system control and protection at 40.5kV. It is compatible with combined breaker and capacitor bank installations and includes current transformers for monitoring. The LW34-40.5 breaker uses the CT14 spring-operated mechanism to ensure reliable and efficient operation.

Type designation of LW34-40.5  T2000-40

Here’s the detailed explanation of the model code:

• L: SF6 breaker (indicates the use of SF6 gas as the arc-extinguishing medium).
• W: Outdoor type (suitable for outdoor installation).
• 8: Design sequence number.
• 40.5: Rated voltage (kV).
• (W): Dirtiness resistance or pollution-resistant type (optional).
• T: Spring mechanism type.
• 2000: Rated current (A).
• 40: Rated short-circuit breaking current (kA).

Operating Conditions for AC SF6 Circuit Breakers

• Altitude: ≤3000m
• Temperature: -30°C to +45°C
• Pollution Level: ≤Grade IV as per GB/T5582
• Humidity: Daily ≤95%, monthly ≤90% (at 25°C)
• Wind Pressure: ≤700Pa (up to 34 m/s wind speed)
• Daily Temperature Variation: ≤25℃.
• Sunlight Intensity: ≤0.1W/cm².
• Monthly Average Relative Humidity: ≤90%.
• Seismic Intensity: Horizontal acceleration ≤0.2g, vertical acceleration ≤0.1g.
• Ice Coating Thickness: ≤10mm.
• Installation Conditions: Designed for outdoor use.

For special environmental requirements, please contact the manufacturer to discuss custom solutions.

Product Structure Features

• Compact Outdoor Design: Features a small ceramic column structure paired with the CT14 spring-operated mechanism. Simple installation, reliable operation, and ideal for frequent use. Mechanism lifespan exceeds 3000 cycles.
• Advanced Arc-Extinguishing System: Utilizes air-compression arc-extinguishing technology with a strong breaking capacity. Supports up to 12 breaks at 40kA for superior performance.
• Superior Sealing Performance: Equipped with imported seals and “V”-type dynamic seals with spring pressure compensation. Ensures an annual leakage rate of less than 1%, with high-quality secondary wiring boards from trusted partners.
• High-Precision Current Transformers: Built-in transformers use micro-crystalline alloy materials with accuracy up to 0.2 or 0.2S grade. Supports up to 12 transformers to manage load lines up to 50 km without restrike.

Application Areas for LW8-36 SF6 Circuit Breaker

• Urban Power Distribution: Ensures dependable current management in high-density urban areas, prioritizing safety and operational efficiency.
• Industrial Power Systems: Delivers unmatched reliability and safety for seamless industrial operations, minimizing downtime and maximizing productivity.
• Rural Electrification: Provides stable and durable power distribution solutions tailored for remote and environmentally challenging locations.
• Substation Protection: Plays a vital role in managing and safeguarding power flow between substations, ensuring grid stability and continuity.

Technical Parameters

• Rated Insulation: Lightning impulse withstand voltage of 185kV and power frequency withstand voltage of 95kV.
• Durability: Supports 3000 operations with a breaking current of 40kA.

Table 1

Item		Unit	Data
Rated Voltage		KV	40.5
Rated Insulation Level	Lightning Impulse Withstand Voltage (Peak)	KV	185
	1min Power Frequency Withstand Voltage	KV	95
Rated Current		A	2000
Mechanical Life		Times	3000
SF6 Gas Rated Pressure (20°C Gauge Pressure)		Map	0.50
Alarm Pressure / Minimum Functional Pressure (20°C Gauge Pressure)		Map	0.47 / 0.45
Rated Short-Circuit Breaking Current		kA	40
Rated Short-Circuit Closing Current (Peak)		kA	100
Rated Short-Time Withstand Current (Thermal Stability Current)		kA	40
Rated Peak Withstand Current (Dynamic Stability Current)		kA	100
Accumulated Breaking Times at Rated Short-Circuit Current		Times	12
Rated Short-Time Duration		s	4
Closing Time (At Rated Operating Voltage)		s	≤0.1
Opening Time (At Rated Operating Voltage)		s	≤0.6
Rated Operating Sequence			0–0.3s–CO–180s–CO
Rated Capacitor Switching Current		A	400
Annual Leakage Rate		%	≤1
SF6 Gas Moisture Content (V/V)			≤15 0×10⁻⁶
Rated Operating Voltage with CT4 Spring Mechanism		V	AC: 220 380 DC: 48 110 220
Energy Storage Motor Voltage		V	AC: 220 380 DC: 110 220
SF6 Gas Weight		kg	8
Breaker Weight (Including Mechanism)		kg	1400

Note: For special customization, such as unique configurations or non-standard operating conditions, please contact our technical team for tailored solutions.

Table 2

Item	Unit	Data	Technical Requirements
Moving Contact Stroke	mm	95 ± 2	Measure the stroke of the moving contact
Contact Opening Distance	mm	60 ± 1.5	Measure the distance between moving and stationary contacts
Closing Synchronization	ms	≤2	Measure the difference in the distances between moving and stationary contacts in each phase
Opening Synchronization	ms	≤3	Measure the difference in the distances between moving and stationary contacts in each phase
Main Circuit Resistance	mΩ	≤120	Measure using the DC voltage drop method, with current applied during measurement
Closing Speed	m/s	3.2 ± 0.2	Measure at rated gas pressure
Opening Speed	m/s	3.4 ± 0.2	Measure at rated gas pressure
Closing Buffer Stroke	mm	10	Measured in the closed position
Closing Buffer Gap	mm	1 ~ 2	Measured in the closed position
Partial Discharge 48.6kV	Pc	20	At rated gas pressure, measure using partial discharge test equipment at 48.6kV applied voltage for 1 minute, then reduce to 28kV for measurement
Discharge 28kV	Pc	10

Table 3

Item	Unit	Data
Rated Operating Voltage (V)	V	DC: 110, 220; AC: 220, 380
Rated Motor Current (A)	A	5
Normal Operating Voltage Range		85% ~ 110% of Rated Operating Voltage
Energy Storage Time Under Rated Voltage	S	Less than 15

Table 4

Closing Electromagnet	Rated Operating Voltage (V)	~220	~380	~48	~110	~220
	Rated Motor Current (A)	3.5	2	9.6	3.4	1.7
	Resistance at 20°C (Ω)	3.9	10.2	5	32	129
	Normal Operating Voltage Range	Closing Rated Voltage: 80% ~ 110%
Opening Electromagnet	Rated Operating Voltage (V)	~220	~380	~48	~110	~220
	Rated Motor Current (A)	35	2	12	4.6	2.3
	Resistance at 20°C (Ω)	7	23.5	4	24	95
	Normal Operating Voltage Range	Opening Rated Voltage: 62% ~ 120%

Outline and Dimensions

1. Outlet Cap	4. CT Connection Protective Tube	7. Base Frame
2. Bushing	5. Pole Attachment	8. Gas Pipeline
3. Current Transformer	6. Enclosure	9. Open/Close Indicator
10. Nameplate	11. Transmission Box	12. Trip Spring

Ordering Guidelines and Special Requirements

To ensure the LW8(A)-40.5, LW16-40.5, or LW34-40.5 High-Voltage AC SF6 Circuit Breakers meet your needs, please provide the following details when placing your order:

• Basic Specifications: Model and Type, Rated Voltage/Current, Short-Circuit Breaking Current
• Environmental and Operating Conditions: Temperature, Pollution Level
• Control and Mechanisms: Control Voltage, Energy Storage Voltage, Current Transformers
• Special Requirements: Custom Configurations, Additional Testing/Certifications

Customization Options

For non-standard designs, enhanced performance, or specific project needs, contact our technical team. We provide tailored solutions to meet your requirements. Contact us today for assistance or to place your order!

FAQs for LW8 AC SF6 Circuit Breakers

1. What are the main applications of the LW8(A)-40.5 SF6 Circuit Breaker?
   It is ideal for 40.5kV transmission systems, capacitor bank installations, and substation protection in urban grids, industrial plants, and rural power systems.
2. How does the LW8(A)-40.5 handle extreme environmental conditions?
   The breaker features advanced sealing technology with ceramic and stainless steel components, ensuring reliable performance in temperatures ranging from -30°C to +45°C and high pollution levels.
3. What is the arc-extinguishing capacity of the LW8(A)-40.5?
   The breaker can handle up to 40kA short-circuit breaking currents with 12 breaking operations at rated capacity, ensuring superior fault management.
4. Does the LW8(A)-40.5 support automation and smart grids?
   Yes, it is compatible with advanced control systems, offering real-time monitoring and remote operation through integrated current transformers.
5. What are the maintenance requirements for the LW8(A)-40.5?
   Minimal maintenance is required due to its fully sealed SF6 insulation, reducing operational costs and downtime over its 3,000-operation lifespan.
6. Can the LW8(A)-40.5 be customized for specific needs?
   Yes, it offers flexible configurations, including custom CT ratios, enhanced insulation, and tailored mechanisms for unique project requirements. Contact the technical team for further assistance.

• Common Fault Handling for Current and Voltage Transformers
• Analysis of the Impact of Current Transformer Faults on Energy Meter Accuracy
• 3 Voltage Transformer Faults and Solutions: Ensuring Accurate Measurement and Protection
• Zero-Sequence Current Transformer Protection Principle and Applications
• Causes and Solutions for False Fault Alarms in Zero-Sequence Current Transformers
• Causes, and Solutions for Abnormal Heating in 10KV Current Transformers