Siemens 38-3AH3 38 kV Rated Maximum design voltage, Levels Voltage levels Lightning-impulse BIL

Appendix

Table 13: Type 38-3AH3 vacuum circuit breaker ratings (historic "constant MVA" ratings basis)

			Measured parameter			Units	Circuit breaker type1
							38-3AH3-1500
	General				Nominal voltage class	kV	38.0
			Nominal three-phase MVA class9			MVA	1500
Rated		Rated		Maximum design voltage (V)2		kV rms	38.0
values		voltage
					Voltage range factor (K)3	----	1.65
		Insulation	Withstand		Power-frequency	kV rms	80
		levels	voltage levels
					Lightning-impulse (BIL)	kV peak	150
		Rated			Continuous4	A rms	1,200, 2,000, 3,000FC
		current
			Short-circuit (at rated maximum design voltage) (I)5, 6, 10			kA rms sym	21
					Interrupting time11	Cycles/ms	5/83
				Permissible tripping delay (Y)		Sec	2
Related		Current	Rated maximum design voltage (V) divided by K = (V/K)			kA rms	23.0
required
			Maximum symmetrical (sym) interrupting (K x I)			kA rms sym	35
capabilities
		Short-time current (K x I) (three-seconds)			kA rms sym	35
		Closing and			Asymmetrical (1.55 x I)8	kA rms	56
		latching
					Peak (2.6 x I)8	kA peak	95
		(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.

Footnotes:

1“xxxx” in type designation refers to the 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.

2Maximum design voltage the circuit breaker is designed for and the upper limit for operation.

3K 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.

43000FC indicates fan cooling is included in the switchgear structure for this rating. 3000 A rating is not available in outdoor equipment.

5To 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 maximum design voltage, the required symmetrical interrupting capability of the circuit breaker shall be equal to K times rated short-circuit current.

6Within the limitations stated in ANSI/IEEE 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.

7Current 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.

8Current values in this row are independent of operating voltage up to and including rated maximum voltage.

9"Nominal three-phase MVA class" is included for reference only. This information is not listed in ANSI/IEEE C37.06-1987.

10Standard duty cycle is CO - 15s - CO.

11Three-cycle (50 ms) interrupting is optionally available.

65