3AH37 and 3AH38 vacuum generator circuit-breakers for power stations and industry

Answers for energy.

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No doubt that also during the next few years the worldwide demand for energy will increase dramati-cally. Consequently, energy suppliers and industrial companies must face up to increased demands for higher power and current. In order that companies in this sector are always the one decisive step ahead, Siemens has been constantly developing and opti-mizing high-current and generator circuit-breakers. A high degree of reliability and maintenance-free operation are of the highest priority. The circuit breakers are designed for the highest operating currents and are outstanding with their highly durable contact material, a design that’s optimized for cooling, and maximum mechanical stability. That increases the performance and reliability of the entire switchgear from Siemens and permanently lowers life-cycle costs.

3AH37 and 3AH38 – reliable switching capacity for up to 72 kA and 6300 A operating currentIn numerous power stations around the world, the 3AH38 high-current and generator circuit-breaker has become the standard for switching rated operating currents up to 4000 A. The 3AH38 is the first 63 kA and 72 kA vacuum circuit-breaker in the world that has been type-tested in accordance with the criteria of the generator circuit-breaker guideline IEEE Std C37.013. With the 3AH37, Siemens is offering the first internationally available vacuum circuit-breaker for higher generator power capacities which can carry an operating current of 6300 A on a sustained basis up to 24 kV without forced-air cooling. In addition at 24 kV, it can handle short-circuit currents up to 63 kA, and at 17.5 kV even up to 72 kA.

Grow with your requirements

Whether it’s vacuum interrupters, vacuum circuit-breaker or complete switchgear, Siemens has the solution for every need

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Over 35 years of experience in vacuum switching technologyHigh-current circuit-breakers are subject to very high thermal and mechanical loads. Therefore, a long circuit-breaker service life and appropriately low maintenance costs require a wide range of technical knowledge. Optimum contact material for minimum electrode erosion, the optimal design for efficient cooling, the most suitable construction for mechanical stability – these demands have been constantly placed on Siemens and met by them in over 35 years of vacuum circuit-breaker technology. Not only the comprehensive simulations and preliminary investi-gations, but also the consistent use of the latest development technologies and modern manufacturing processes ensure that Siemens maintains its leading position in the production of medium-voltage vacuum circuit-breakers in the long term.

Modular construction for maximum flexibilityThe circuit-breaker has been modularly constructed in order to be able to use the best materials for the current circuit, magnetic flux and cooling. In this way, features such as low resistance of the main circuit, high mechanical stability and ideal cooling behaviour have been combined in the 3AH37. And that’s not all! Because of the modular construction, the circuit-breaker can also be installed horizontally when required. The heat-exchanger elements are mounted simply rotated through 90° and also allow optimal convection and cooling in this position. The 3AH37 can be operated continuously in every position without any additional fans and does not overheat.

Modular high current and generator circuit-breakers from Siemens offer concrete benefits in everyday operation:

High mechanical stability through the column ■

constructionCompact dimensions through vertical arrangement ■

of the vacuum interruptersLow fire load as solid insulation is not required ■

No forced cooling required because of free convection ■

Secondary equipment can be easily retrofitted ■

Maintenance-free throughout its entire service life ■

Suitable for horizontal and vertical installation ■

Type-tested according to IEEE Std C37.013-1997 ■

Overview of 3AH37 / 3AH38 portfolio

17.5 kV Rated short-circuit breaking current / rated short-circuit making current

Rated operating current 50 kA / 137 kA 63 kA / 173 kA 72 kA / 198 kA

3150 A 3AH3817-7 3AH3818-7 3AH3819-7

4000 A 3AH3817-8 3AH3818-8 3AH3819-8

5000 A 3AH3712-4 3AH3713-4 3AH3714-4

6300 A 3AH3712-5 3AH3713-5 3AH3714-5

24 kV Rated short-circuit breaking current / rated short-circuit making current

Rated operating current 50 kA / 137 kA 63 kA / 173 kA

3150 A 3AH3722-2 3AH3723-2

4000 A 3AH3722-3 3AH3723-3

5000 A 3AH3722-4 3AH3723-4

6300 A 3AH3722-5 3AH3723-5

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17.5 kV Technical data3AH37 and 3AH38

Rated values:

Rated voltage Ur [kV]

Rated frequency [Hz]

Lightning impulse withstand voltage Up [kV]

Short-time power frequency withstand voltage Ud [kV]

Rated short-circuit breaking current ISC [kA] 50 (3s)

Type: 3AH3817-7 3AH3817-8 3AH3712-4 3AH3712-5

Rated normal current Ir [A] 3150 4000 5000 6300

DC component in % DC of short-circuit breaking current [%] 75 75 75 75

Asymmetrical breaking current [kA] 73

Short-circuit making current [kA] 137

Voltage drop ∆U between connections at 100 A [mV] 1.4

Rated operating sequence:

CO – 30 min – CO(Short-circuit breaking current)

O – 3 min – CO – 3 min – CO (Load current & mechanical operation)

Minimum creepage distance:

Vacuum interrupter [mm] 160

Phase to earth [mm] 170 230

Minimum clearance:

Phase to phase [mm] 145 135 230

Phase to earth [mm] 130 230

Measures & weight:

Pole centre distance [mm] 275 300

Height x width x depth – without phase barriers [mm] 683 x 756 x 590 733 x 776 x 694 915 x 824 x 977

Height x width x depth – with phase barriers [mm] 900 x 776 x 644 1000 x 776 x 811 1180 x 824 x 1051

Weight [kg] 230 320 470 500

Dimension drawing number 3M 32500592 3M 32500593 3M 32500587 3M 32500587

Standard

3AH38

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Proven quality from SiemensType tests as specified in IEC 62271-100 are performed as a rule for all Siemens circuit breakers. Generator circuit-breakers 3AH37 and 3AH38 are also tested in accordance with IEEE Std C37.013. This North American ANSI Standard is the only worldwide standard to take into account the increased requirements to which equipment is subjected when switching generators. As a result, it has also become the leading standard for generator circuit-breakers in IEC- oriented professional circles. It addresses in particular missing zero crossings with generator-side faults, higher DC components, higher test voltage levels and higher TRV rates of rise for mains- operated faults.

17.5

50 / 60

110

50

63 (3s) 72 (3s)

3AH3818-7 3AH3818-8 3AH3713-4 3AH3713-5 3AH3819-7 3AH3819-8 3AH3714-4 3AH3714-5

3150 4000 5000 6300 3150 4000 5000 6300

65 65 65 65 65 65 65 65

86 98

173 198

1.4 1.4

160 160

170 230 170 230

145 135 230 145 135 230

130 230 130 230

275 300 275 300

683 x 756 x 590 733 x 776 x 694 915 x 824 x 977 683 x 756 x 590 733 x 776 x 794 915 x 824 x 977

900 x 776 x 644 1000 x 776 x 811 1180 x 824 x 1051 900 x 776 x 644 1000 x 776 x 811 1180 x 824 x 1051

230 320 470 500 250 320 470 500

3M 32500019 3M 32500030 3M 32500588 3M 32500588 3M 32500019 3M 32500030 3M 32500589 3M 32500589

According to IEEE Std C37.013 for generator switching application

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3AH37

Rated values:

Rated voltage Ur [kV]

Rated frequency [Hz]

Lightning impulse withstand voltage Up [kV]

Short-time power frequency withstand voltage Ud [kV]

Rated short-circuit breaking current ISC [kA] 50 (3s)

Type: 3AH3722-2 3AH3722-3

Rated normal current Ir [A] 3150 4000

DC component in % DC of short-circuit breaking current [%] 75 75

Asymmetrical breaking current [kA] 73

Short-circuit making current [kA] 137

Voltage drop ∆U between connections at 100 A [mV] 1.4

Rated operating sequence:

CO – 30 min – CO(Short-circuit breaking current)

O – 3 min – CO – 3 min – CO (Load current & mechanical operation)

Minimum creepage distance:

Vacuum interrupter [mm] 160

Phase to earth [mm] 170

Minimum clearance:

Phase to phase [mm] 230

Phase to earth [mm] 230

Measures & weight:

Pole centre distance [mm] 300

Height x width x depth – without phase barriers [mm] 915 x 824 x 977

Height x width x depth – with phase barriers [mm] 1180 x 824 x 1051

Weight [kg] 320 350

Dimension drawing number 3M 32500842 3M 32500597

Standard

3AH37

24 kV Technical data

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24

50 / 60

125

60

63 (3s)

3AH3722-4 3AH3722-5 3AH3723-2 3AH3723-3 3AH3723-4 3AH3723-5

5000 6300 3150 4000 5000 6300

75 75 65 65 65 65

86

173

1.4

160

230 170 230

230 230 230

230 230 230

300

915 x 824 x 977

1180 x 824 x 1051

470 500 320 350 470 500

3M 32500840 3M 32500841 3M 32500835 3M 32500836 3M 32500837 3M 32500838

According to IEEE Std C37.013 for generator switching application

More power for growing energy demands The global increase in the demand for energy requires ever greater generator power capacities. In order to accommodate these increasing requirements, switchgear must be able to withstand increasing currents and voltages. Siemens has the solution for this: The 3AH37 is the first internationally available vacuum circuit-breaker which can carry an operating current of 6300 A on a sustained basis up to 24 kV without forced-air cooling.

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Subject to change without prior notice.The information in this document contains generaldescriptions of the technical options available, whichmay not apply in all cases. The required technicaloptions should therefore be specified in the contract.