LW36-126

Outdoor high-voltage AC SF6 circuit breaker

Outdoor SF6 circuit breaker with self-blast arc quenching and spring-operated mechanism for 126 kV, 50 Hz networks. It switches rated and short-circuit currents for line control and protection and can also serve as a bus-coupler breaker.

Key parameters

Rated voltage: 126 kV
Rated current: 3150 A
Rated short-circuit breaking current: 40 kA
Operating mechanism: spring-operated
Mechanical endurance: 10,000 operations

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General information

LW36-126/3150-40 is a high-voltage AC SF6 circuit breaker with self-blast (self-generated pressure) arc quenching, designed for outdoor installation. It is intended for 50 Hz AC networks with a highest voltage of 126 kV at altitudes up to 2000 m (a version for altitudes above 3000 m is available), at ambient temperatures not below −40 °C and pollution level not higher than IV. It is used to break rated current and short-circuit current or to switch lines, providing control and protection of the power system; it can also be used as a bus-coupler (tie) circuit breaker.

SF6 gas is used as the arc-quenching and insulating medium. The breaker employs state-of-the-art self-blast arc-quenching technology and a new spring operating mechanism. It features long service life, low operating power, low noise and high reliability; simple design, small dimensions and long maintenance intervals. It is in line with the move of power equipment towards oil-free, high-capacity apparatus.

Type designation

LW36-126(W)/T3150-40

L	SF6 circuit breaker
W	Outdoor installation
36	Design serial number
126	Rated voltage, kV
(W)	Version for polluted areas (reinforced insulation)
T	Spring operating mechanism
3150	Rated current, A
40	Rated short-circuit breaking current, kA

Main technical parameters of the operating mechanism

Parameter		Unit	Value
Auxiliary circuit voltage		V	DC 220 or DC 110
Closing and opening coil voltage / current		V/A	DC 110/4; DC 220/2
Spring charging motor	Rated voltage	V	DC 220, AC 220 / DC 110, AC 110
	Normal operating voltage range	V	85 % … 110 %
	Power	W	600
Spring charging time by motor		s	≤ 15
Heating and lighting circuit voltage		V	AC 220
Rated voltage of auxiliary contacts		V	DC 220, AC 220
Rated current of auxiliary contacts		A	10
Number of auxiliary contacts			10 normally open + 10 normally closed

Main technical parameters

Parameter		Unit	Value
Rated voltage		kV	126
Rated power-frequency withstand voltage	To earth	kV	K · 230
Rated power-frequency withstand voltage	Across open contacts		K · 265
Rated lightning impulse withstand voltage	To earth		K · 550
Rated lightning impulse withstand voltage	Across open contacts		K · 630
Power-frequency withstand voltage at zero SF6 gauge pressure (5 min)			K · 95
Rated frequency		Hz	50
Rated current		A	3150
First-pole-to-clear factor			1.5
Rated short-circuit breaking current		kA	40
Rated short-circuit making current (peak)		kA	100
Rated short-time withstand current			40
Rated peak withstand current			100
Rated duration of short circuit		s	4
Rated out-of-phase breaking current		kA	10
Short-line fault breaking current		kA	90 % I_sc, 75 % I_sc
Rated line-charging breaking current		A	31.5
Rated operating sequence			O–0.3 s–CO–180 s–CO
Main circuit resistance		µΩ	≤ 40
Rated SF6 pressure (gauge, at 20 °C)		MPa	0.6
Alarm pressure / minimum functional pressure (gauge, at 20 °C)		MPa	0.55 ± 0.03 / 0.50 ± 0.03
Annual SF6 leakage rate			< 0.5 %
Gas moisture content (by volume)			≤ 150×10⁻⁶
Mechanical endurance		operations	10000
Radio interference level		µV	≤ 500
Creepage distance	Across open contacts	mm	3906/3150
Creepage distance	To earth	mm	3906/3150
SF6 mass per circuit breaker		kg	10
Mass of one circuit breaker		kg	1500

Note. External insulation is corrected by the altitude factor K: altitude 2000 m — K = 1.13; altitude 3000 m — K = 1.28.

SF6 circuit breaker range

LW3-12 — outdoor high-voltage SF6 circuit breaker

LW36-40.5 — outdoor high-voltage SF6 circuit breaker

PGS-24 — pole-mounted high-voltage SF6 circuit breaker

PGS — pole-mounted high-voltage SF6 circuit breaker (with cast cable terminal)

PGS — pole-mounted high-voltage SF6 circuit breaker (with surge arresters)

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