Medium-voltage vacuum generator circuit breakers, drawout type GMSG-GCB

15 kV

For 10 MW to 80 MW machines
Rated short-time withstand current up to 63 kA
Rated continuous current up to 4,000 A fan-cooled

Drawout type GMSG-GCB, medium-voltage vacuum generator circuit breakers

Drawout type generator circuit breakers for use in type GM-SG metal-clad switchgear are available. These circuit breakers are derived from the same type 3AH3 family of circuit breaker operating mechanisms as our standard non-generator circuit breakers. The basic design of the circuit breakers is the same, making maintenance and operation of the generator circuit breakers the same as for non-generator circuit breakers. This means that there is no incremental or additional training needed for your maintenance or operational personnel. The type GMSG-GCB generator circuit breakers exploit the long history of successful service provided by the entire type 3A (including types 3AF and 3AH operators) family of vacuum circuit breakers.

These generator circuit breakers fully conform to the requirements for generator circuit breakers as specified in IEEE Std C37.013, "IEEE Standard for AC High Voltage Generator Circuit Breakers Rated on a Symmetrical Current Basis."

Drawout type GMSG-GCB

Features

Features include:

One-high or two-high drawout construction
Up to 50 full-fault interruptions
Front accessible circuit breaker operating mechanism for ease of maintenance
Closed door racking
Floor rollout circuit breaker in lower cell without a dolly
Visible secondary disconnect
Circuit breaker ships inside of cell, thus reducing installation cost and potential transit damage
Pair with Siemens protective relays to provide complete generator protection
Drawout type GMSG-GCB vacuum generator circuit breaker with type 3AH3 operating mechanism
Uses the latest developments in vacuum interrupter technology
Highly reliable vacuum interrupters - MTTF over 50,000 years
Common type 3AH3 operator platform
Over 120,000 type 3AH3 operators produced since 1998
Generator circuit breakers tested to IEEE C37.013/C37.013a
10,000 operations to overhaul
Three-cycle interrupting time (optional)
Meets or exceeds the latest ANSI, IEEE, and NEMA standards
UL or C-UL Listing available
Available in lineups of conventional type GM-SG or GM-SG-AR switchgear, indoor or outdoor
SIERS integrated electrical-racking system available (optional)
Optional arc-resistant construction to ANSI/IEEE C37.20.7, up to 63 kA,
0.5 sec, accessibility type 2B.

For larger machines up to 200 MW, refer to Siemens stationary type vacuum generator circuit breaker offering.

Circuit breaker racking mechanism with fixed-mounted motor

Siemens integrated electrical-racking system (SIERS)

Features and benefits

Siemens integrated electric-racking system (SIERS) is an option that is available with Siemens type GM-SG non-arc-resistant and GM-SG-AR arc-resistant, medium-voltage switchgear. It provides additional personnel protection against arc-flash exposure for operators by providing a means of remotely racking the type GMSG drawout circuit breaker. SIERS reduces the need for personal protective equipment (P.P.E.) per the NFPA-70E® standard.

Standard features:

Maintain all of the safety interlocks as required by IEEE standard C37.20.2
Logic control module for control and circuit protection
Interference detection
Control pendant (hand-held controller)
High-torque, fixed-mounted dc motor
Available for 125 V dc external power supply
Factory installed and tested as a complete racking system.

Optional features:

Powered from 120 V ac sources in switchgear
Provision for external power source
Integrated into the switchgear secondary control circuits or with the protection relay to provide interface with local HMI or SCADA systems
Field retrofit for existing Siemens type GM-SG non-arc resistant and GM-SG-AR arc-resistant, medium-voltage switchgear.

Optional configurations:
Type SIERS device is available in three configurations:

Basic version
Local HMI version (Sm@rtGear™ power distribution solution)
Custom version (i.e., SCADA or other system).

Press release:

Siemens introduces new integrated, electric-racking system to better protect against arc-flash exposure.

Ratings

Rated values and related capabilities			IEEE C37.013 clause	Units	Circuit breaker type³ 15-GMSG-GCB-40- XXXX-110	Circuit breaker type³ 15-GMSG-GCB-50- XXXX-137	Circuit breaker type³ 15-GMSG-GCB-63- XXXX-173
Rated maximum voltage (V)			5.1	kV	15.0	15.0	15.0
Power frequency			5.2	Hz	60	60	60
Rated continuous current			5.3	A	1,200, 2,000, 3,000, 4,000 Fan-Cooled	1,200, 2,000, 3,000, 4,000 Fan-Cooled	1,200, 2,000, 3,000, 4,000 Fan-Cooled
Rated dielectric strength (withstand voltage)	Rated power frequency, one minute		5.4.2 C37.013a, table 4	kV	38	38	38
Rated dielectric strength (withstand voltage)	Impulse		5.4.2 C37.013a, table 4	kV peak	95	95	95
Rated short-circuit duty cycle			5.5		CO-30 min-CO	CO-30 min-CO	CO-30 min-CO
Rated interrupting time^1,2			5.6	ms	< 80	< 80	< 80
Rated short-circuit current	System source (100%) (I)		5.8.1	kA symmetrical	40	50	63
Rated short-circuit current	Generator source (50%)		5.8.2.3	kA symmetrical	20	25	31.5
DC component				%	75	64	61
Asymmetry ratio (historical "S" factor)					1.46	1.35	1.32
Asymmetrical interrupting (ref)				kA	57.9	67.5	83
Delayed current zero capability				ms	40	30	30
Close-and-latch current capability (274% I)				kA peak	110	137	173
Short-time current carrying capability (100% I)			5.8.2.7	kA symmetrical	40	50	63
Short-time current duration			5.8.2.7	s	3	3	3
Transient recovery voltage (TRV) rating	System source	E₂ peak voltage	5.9 C37.013a, table 5	kV	27.6 (1.84 V)	27.6 (1.84 V)	27.6 (1.84 V)
TRV	System source	RRRV (TRV rate)	5.9 C37.013a, table 5	kV/µs	3.5	4.5	4.5
TRV	System source	T₂ time-to-peak	5.9 C37.013a, table 5	µs	9.3 (0.62 V)	7.2 (0.48 V)	7.2 (0.48 V)
TRV	Generator source	E₂ crest voltage	C37.013a, table 6	kV	27.6 (1.84 V)	27.6 (1.84 V)	27.6 (1.84 V)
TRV	Generator source	RRRV (TRV rate)	C37.013a, table 6	kV/µs	1.6	1.8	1.8
TRV	Generator source	T₂ time-to-peak	C37.013a, table 6	µs	20.25 (1.35 V)	18.0 (1.20 V)	18.0 (1.20 V)
TRV	Generator source	E₂ crest voltage	C37.013a, table 6	kV	39.0 (2.6 V)	39.0 (2.6 V)	39.0 (2.6 V)
TRV	Generator source	RRRV (TRV rate)	C37.013a, table 6	kV/µs	3.3	4.1	4.1
TRV	Generator source	T₂ time-to-peak	C37.013a, table 6	µs	13.4 (0.89 V)	10.8 (0.72 V)	10.8 (0.72 V)
Rated load current switching capability			5.10	A	1,200, 2,000, 3,000	1,200, 2,000, 3,000, 4,000	1,200, 2,000, 3,000, 4,000
Out-of-phase current switching capability			5.12	kA	20	25	31.5
Mechanical endurance				Operations	10,000	10,000	10,000

Footnote:

¹ Interrupting time is based on the first current zero occurring not later

than 66 ms after fault initiation, for example, %dc component <100.

² Interrupting time of 50 ms available, provided that the first current

zero occurs no later than 50 ms after fault initiation.

³ "xxxx" in type designation refers to the continuous current rating 1,200 A,

2,000 A, or 3,000 A, as appropriate. The 4,000 A fan-cooled rating is

achieved using a 3,000 A circuit breaker in combination with fan cooling

in the switchgear structure (indoor only). Assuming 13.8 kV generator

voltage and load current of 4,000 A with fan cooling.

TechTopics is a series of papers that discuss issues of interest to users or specifiers of electrical equipment.

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