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Siemens 38-3AH3 38 kV Instruction Manual page 65

Vacuum circuit breaker
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General
Rated
Rated
values
voltage
Insulation
levels
Rated
current
Related
Current
required
capabilities
Closing and
latching
(momentary)
These ratings are in accordance with:
ANSI/IEEE C37.04-1979 Standard Rating
Structure for AC High-Voltage Circuit
Breakers Rated on a Symmetrical
Current Basis
ANSI C37.06-1987 AC High-Voltage
Circuit Breakers Rated on a Symmetrical
Current Basis - Preferred Ratings and
Related Required Capabilities
ANSI/IEEE C37.09-1979 Standard Test
Procedure for AC High-Voltage Circuit
Breakers Rated on a Symmetrical
Current Basis
ANSI/IEEE C37.010-1979 Application
Guide for AC High-Voltage Circuit
Breakers Rated on a Symmetrical
Current Basis.
Appendix
Table 13: Type 38-3AH3 vacuum circuit breaker ratings (historic "constant MVA" ratings basis)
Measured parameter
Nominal voltage class
Nominal three-phase MVA class
Maximum design voltage (V)
Voltage range factor (K)
Withstand
voltage levels
Lightning-impulse (BIL)
Continuous
Short-circuit (at rated maximum design voltage) (I)
Interrupting time
Permissible tripping delay (Y)
Rated maximum design voltage (V) divided by K = (V/K)
Maximum symmetrical (sym) interrupting (K x I)
Short-time current (K x I) (three-seconds)
Asymmetrical (1.55 x I)
Peak (2.6 x I)
Footnotes:
"xxxx" in type designation refers to the
1
continuous current rating 1,200, 2,000, or
3,000 A, as appropriate. The 3,000A fan-cooled
rating is achieved using fan cooling as
indicated in Footnote 4.
Maximum design voltage the circuit breaker is
2
designed for and the upper limit for operation.
K is the ratio of the rated maximum design
3
voltage to the lower limit of the range of
operating voltage in which the required
symmetrical and asymmetrical interrupting
capabilities vary in inverse proportion to the
operating voltage.
4
3000FC indicates fan cooling is included in the
switchgear structure for this rating. 3000 A
rating is not available in outdoor equipment.
To obtain the required symmetrical
5
interrupting capability of a circuit breaker at an
operating voltage between 1/K times rated
maximum design voltage and rated maximum
design voltage, the following formula shall be
used: Required Symmetrical Interrupting
Capability =Rated Short-Circuit Current (I) x
[(Rated Maximum Design Voltage)/(Operating
voltage)].
9
2
3
Power-frequency
4
5, 6, 10
11
8
8
Units
Circuit breaker type
38-3AH3-1500
kV
MVA
kV rms
----
kV rms
kV peak
A rms
1,200, 2,000, 3,000FC
kA rms sym
Cycles/ms
Sec
kA rms
kA rms sym
kA rms sym
kA rms
kA peak
For operating voltages below 1/K times
maximum design voltage, the required
symmetrical interrupting capability of the
circuit breaker shall be equal to K times rated
short-circuit current.
Within the limitations stated in ANSI/IEEE
6
C37.04-1979, all values apply to polyphase and
line-to-line faults. For single phase-to-ground
faults, the specific conditions stated in clause
5.10.2.3 of ANSI/IEEE C37.04-1979.
Current values in this row are not to be
7
exceeded even for operating voltage below 1/K
times rated maximum design voltage. For
operating voltages between rated maximum
design voltage and 1/K times rated maximum
design voltage, follow Footnote 5.
Current values in this row are independent of
8
operating voltage up to and including rated
maximum voltage.
"Nominal three-phase MVA class" is included
9
for reference only. This information is not listed
in ANSI/IEEE C37.06-1987.
Standard duty cycle is CO - 15s - CO.
10
Three-cycle (50 ms) interrupting is optionally
11
available.
1
38.0
1500
38.0
1.65
80
150
21
5/83
2
23.0
35
35
56
95
65

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