LW8A-40.5 High Voltage SF6 Circuit Breaker

Our LW8A-40.5 outdoor porcelain column type high voltage SF6 circuit breakers are designed for control and protection in 40.5kV AC 50Hz power systems, featuring a single-column, single-break per pole design with self-energy arc-extinguishing technology.

• Rated voltage of 40.5kV with rated current up to 2000A; rated short-circuit breaking current up to 31.5kA with peak withstand current up to 80kA for robust fault interruption.

• Self-energy arc-extinguishing principle ensures excellent interrupting performance; equipped with CT14 spring-operated mechanism and three-phase mechanical linkage.

• Mechanical endurance of 10,000 operations with annual SF6 gas leakage rate ≤0.5% for exceptional long-term reliability.

• Total break time ≤110ms with opening time of 60-80ms and closing time of 90-120ms; electrical endurance of 20 operations at rated short-circuit breaking current.

• Equipped with current transformers for measurement and protection; complies with GB1984 and IEC 62271-100 standards.

• Seismic withstand capability of 0.250g horizontal acceleration, pollution severity Class III, and degree of protection IP5XW for harsh outdoor environments.

• Fast delivery, reliable quality, responsive service, and extensive project experience backed by our company.

Product Overview

The LW8A-40.5 outdoor porcelain column type high voltage SF₆ circuit breaker is suitable for use in AC 50Hz power systems with a rated voltage of 40.5kV. It serves as a control and protection device for power systems and can also be used as a tie circuit breaker. The breaker is additionally equipped with current transformers for measurement and protection purposes.

The circuit breaker uses sulfur hexafluoride (SF₆) gas as the insulation and arc-quenching medium. It features a single-column, single-break per pole design, utilizes the self-energy arc-extinguishing principle, is fitted with a CT14 spring-operated mechanism, and has three-phase mechanical linkage.

This product complies with the GB1984 and IEC 62271-100 standards.

Technical Specifications

S.Q.	Item		Unit	Technical Parameter
1	Altitude		m	1000		2000
2	Ambient Air Temperature		-	-30℃~40℃	-40℃~40℃	-30℃~40℃	-40℃~40℃
3	Rated Voltage		kV	40.5		40.5
4	Rated Frequency		Hz	50		50
5	Rated Current		A	2000		2000
6	Rated Short-circuit Breaking Current Isc		kA	31.5	25	31.5	25
7	Rated Short-time Withstand Current / Duration		kA/s	31.5/4	25/4	31.5/4	25/4
8	Rated Peak Withstand Current (peak)		kA	80	63	80	63
9	Rated Short-circuit Making Current (peak)		kA	80	63	80	63
10	First-pole-to-clear Factor		-	1.5		1.5
11	Rated Out-of-phase Breaking Current		kA	Isc25%		Isc25%
12	1-minute Power-frequency Withstand Voltage (r.m.s.)	Across the isolating distance	kV	95+24	95	95	95
		To earth		95	95	95	95
13	Lightning Impulse Withstand Voltage (peak)	Across the isolating distance	kV	185+33	185	185	185
		To earth		185	185	185	185
14	Total Break Time		ms	≤110		≤110
15	Opening Time		ms	60.0~80.0		60.0~80.0
16	Closing Time		ms	90.0~120.0		90.0～120.0
17	Open-Close Time		ms	300.0		300.0
18	Close-Open Time		ms	100.0～120.0		100.0～120.0
19	Electrical Endurance		times	20		20
20	Mechanical Endurance		times	10000		10000
21	SF₆ Gas Annual Leakage Rate			≤0.5%		≤0.5%
22	Rated Operating Duty		-	O-0.3s -CO-180s-CO		O-0.3s -CO-180s -CO
23	Opening / Closing Coil Supply Voltage		V	DC220;110		DC220;110
24	Trip Circuit Current		A	2.3;4.6		2.3;4.6

Model and Its Designation

LW 8A - 40.5

LW: Outdoor SF₆ Circuit Breaker

8A: Design Serial Number

40.5: Rated Voltage (kV)

Normal Service Conditions

1. Solar Radiation: 1000 W/m²;

2. Relative Humidity: Daily Average ≤ 95%; Monthly Average ≤ 90%;

3. Wind Speed: Not exceeding 34 m/s;

4. Seismic Withstand Capability: Horizontal Acceleration: 0.250g; Vertical Acceleration: 0.125g;

5. Pollution Severity: Class III (25 mm/kV);

6. Ice Coating Thickness: 10 mm (when wind speed does not exceed 15 m/s);

7. Degree of Protection: IP5XW.

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