circuit-breaker with for

LTB E is an type circuit-breaker designed for system voltages 245 -550 kV and for rated short-circuit currents upto 50 kA. The design incorporates animproved interrupter based onexperience gained from previous interrupterdesigns.

The energy required for interrupting short-circuit currents is taken partly from the arcitself, thereby reducing the energy requiredfrom the operating mechanism by more than50 percent compared with a conventionalpuffer type circuit-breaker.

The low energy requirements result in a de-sign optimized for the low operating forceswhich in turn results in higher reliability.

All single pole operated circuit-breakers areequipped with one operating mechanism perpole. Circuit-breakers with one breaking unitper pole can be operated with one operatingmechanism per breaker.

The LTB E circuit-breaker complies with theinternational standards IEC and ANSI.

Main features and advantages

The LTB circuit-breaker family satisfies thehighest demands. It is based on latest develop-ments in dielectric dimensioning and arcresearch. Advantages are as follows:

Restrike-free interruption of capacitive currents due to optimized contact design and movement.

Low overvoltages when switching inductive currents due to optimum quenching at current zero.

High dielectric strength even at atmospheric

Long maintenance intervals due to separate current

The circuit-breakers have passed type tests according to IEC. Mechanical endurance tests have been performed to 10 000 operations. Before delivery each circuit-breaker must pass routine tests in accordance with IEC and ANSI. For each breaker a routine test report is issued showing actual test results.

Testing

The breaker pole constitutes a sealed unit, whichincludes one or two breaking unit(s), support andoperating insulators, and pole linkage housing. Tothe latter the tripping spring is attached.

To ensure the quality of the gas, each breakeris provided with a filter for moisture absorption.

Design

Auto-Puffer

Auto-Puffer

Auto-Puffer

SF6

SF6

SF6

SF6

outdoor installation

SF6 pressure due to optimized contact gap.

High security against gas leakage due todouble X-rings in all dynamic seals and doubleO-rings in static seals, verified during morethan 30 years of field operation at varying

climatic conditions. (SF6 gas loss much less than 1

percent/year.)

paths for continuous and arcing currents,respectively.

Reliable components due to all parts optimized,aided by advanced computer technology, forelectrical and mechanical stresses.

High seismic withstand capability due to optimizedpole and structure.

Low noise level due to low mechanical energyrequired for operation.

Easy installation and commisioning. Each circuit-breaker is pre-tested and shipped to erection site inform of a few pre-assembled units.

Optional synchronized switching due tosynchronizing relay type Switchsync.

Optional supervisory control due to conditionmonitoring type Switchguard / Switchcontrol.

Technical Data

LTB245E1 420E2 420E2 550E2

Values complying with IEC 56 (50 Hz), other values on request.

Number of breaks per poleRated voltagePower frequency withstand voltage (1 min): To earth Across open poleLightning Impulse Withstand Level (LIWL): To earth Across open poleSwitching Impulse Withstand Level (SIWL): To earth Across open poleMimimum creepage distanceRated normal currentRated breaking currentFirst pole to clear factorMaking current / peakDuration of short-circuitClosing timeOpening timeTotal break timeDead timeRated operating sequence

kV

kVkV

kVkV

kVkVmm/kVAkA

kAsmsmsmsms

1245

460460

10501050

--254000401.310034017240300O - 0.3 sec - CO - 3 min - COAlt: CO - 15 sec - CO

2362

520450

11751175(+205)

950800(+295)254000501.312537018240300

2420

520610

14251425(+240)

1050900(+345)254000501.312537018240300

The circuit-breaker is operated by motor chargedspring operating mechanism, which is installed in acompact splash-proof and corrosion resistanthousing, attached to the structure.

Three BLK 222s are used for single pole operation at 245 kV.

One BLG 1002A is used for three pole operation at 245 kV.

Three BLG 1002As are used for single-pole operation at 420 kV.

For further details please see pamphletsSESWG/B2504en and SESWG/B 2510en.

The LTB E circuit-breaker poles are transported ascomplete units filled with gas to a slightoverpressure. Circuit-breaker poles with twobreaking units per phase are supplied as twoseparate units: breaker-head and support insulator.The circuit-breaker is routine tested in the factory.

Erection work at site can be done in less than oneday.

Filling of gas to specified working pressure isdone by using the following pressurizing equipment:

One special control valve, for connection to the gas bottle, and a gas-filled hose with connectors.

Gas filling can be done without gas being released into the atmosphere.

No gas treatment is necessary before gas filling.

Operating mechanism Transport and erection

SF6

SF6

SF6

SF6

2550

620800

15501550(+315)

1175900(+450)254000501.312537018240300

ABB Switchgear ABSE-771 80 LUDVIKA, SwedenTel: +46 240 78 20 00Fax: +46 240 78 36 50E-mail: circuit.breaker@se.abb.comInternet: www.abb.se/swg

Dimensions

LTB 245E1 LTB 245E1

PLEASE NOTE! ABB Switchgear is working to continuously improve the products.Therefore we reserve the right to change design, dimensions and data without prior notice.

LTB 420 - 550E21-pole operation with BLG 1002A

Publ. SESWG/B 2332enEdition 2, 1999-07

Pro

d. S

ES

WG

/BF

S

J Circuit breaker

Type LTB 420E2

Type LTB 550E2

F

3105

4135

G

1914

1914

H

4882

4882

J

6541

7571

Dimensions (mm)

1-pole operation with BLK 222 3-pole operation with BLG 1002A