47
Appendix
Measured Parameter Units 5-GMI- 5-GMI- 7-GMI- 15-GMI- 15-GMI- 15-GMI-
250 350 500 500 750 1000
General
Nominal Voltage Class kV 4.16 4.16 7.2 13.8 13.8 13.8
Nominal 3-Phase MVA Class
9
MVA 250 350 500 500 750 1000
Rated
Maximum Design Voltage (V)
2
kV rms 4.76 4.76 8.25 15.0 15.0 15.0
Voltage
Voltage Range Factor (K)
3
— 1.24 1.19 1.25 1.30 1.30 1.30
Power
kV rms 19 19 36 36 36 36
Insulation Withstand
Frequency
Levels
Voltage Levels
Lightning
kV crest 60 60 95 95 95 95
Impulse (BIL)
Rated 1200 1200 1200 1200
Values Continuous
4
A rms
1200
2000 2000
1200
2000 2000
2000
3000FC 3000FC
2000
3000FC 3000FC
Rated Short-Circuit (at rated maximum kA rms
Current design voltage) (I)
5 6 10
sym
29 41 33 18 28 37
Interrupting Time Cycles 5 5 5 5 5 5
Permissible Tripping Delay (Y) Sec. 2 2 2 2 2 2
Rated Maximum Design Voltage
KV rms 3.85 4.0 6.6 11.5 11.5 11.5
(V) divided by K (= V/K)
Current
Max. Sym Interrupting (K x 1)
7
kA rms
36 49 41 23 36 48
sym
Related Short Time Current (K x 1)
kA rms 36 49 41 23 36 48
Required (3 seconds)
Capabilities
Closing and Asymmetrical (1.6 x K x 1)
8
kA rms
58
78
66 37 58
77
Latching
78 opt
1
77 opt
1
58 opt
1
77 opt
1
(Momentary)
Peak (2.7 x K x 1)
8
kA peak
97
132
111 62 97
130
132 opt
1
130 opt
1
97 opt
1
130 opt
1
Table A-1A – Type GMI Circuit Breaker Ratings (Historic “Constant MVA” Rating Basis)
These ratings are in accordance with the following standards:
ANSI C37.04-1979 Standard Rating Structure for AC High-Voltage Circuit Breaker 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 C37.09-1979 Standard Test Procedure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis
ANSI C37.010-1979 Application Guide for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis
Circuit Breaker Type
Footnotes:
1
High close and latch (momentary) rating available for special application.
2
Maximum voltage for which the circuit breaker is designed, and the upper limit for operation.
3
K is the ratio of the rated maximum design 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
3000A ratings with VS-10028 vacuum interrupter are self cooled for indoor installations. 3000A ratings using VA-15050
vacuum interrupter and sperate phase barriers require supplemental fan-cooling in the switchgear circuit breaker structure.
3000A ratings using VS-15050 vacuum interrupter and chair design support are self-cooled for indoor installations. Consult
drawings for the switchgear for arrangement provided.
5
To obtain the required symmetrical 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)] For
operating voltages below 1/K times rated maximum design voltage, the required symmetrical interrupting capability of the
circuit breaker shall be equal to K times rated short-circuit current.
6
Within the limitations stated in ANSI 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 C37.04-1979 apply.
7
Current values in this row are not to be 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 above.
8
Current values in this row are independent of operating voltage up to and including rated maximum design voltage.
9
“Nominal 3-Phase MVA Class” is included for reference only — this information is not listed in ANSI C37.06-1987.
10
Standard duty cycle is CO – 15s – CO
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