8DA10 single-bus and 8DB10 double-bus, arc-resistant, gas-insulated switchgear
Rated short-time withstand current up to 40 kA
Rated continuous current of circuit breakers up to 3,000 A
Lightning impulse (BIL) up to 200 kV
Gas-insulated, medium-voltage, arc-resistant switchgear
Medium-voltage (MV) gas-insulated switchgear (GIS) types 8DA10 and 8DB10 are gas-insulated, vacuum circuit breaker designs with a maximum design voltage of 4.16 kV up to 38 kV (42 kV on request). Lightning impulse-withstand voltage ratings up to 200 kV BIL and interrupting ratings up to 40 kA are available.
The types 8DA10 and 8DB10 MV GIS designs feature fixed-mounted vacuum circuit breakers, connectable to the main bus through three-position (CLOSED-OPEN-READY TO GROUND) switches. The position of the switches is indicated by reliable contact position indicators and can also be visibly verified from the front of the unit using a convenient camera system and laptop computer.
MV GIS is approximately 1/5th the size of conventional air-insulated switchgear depending upon the voltage rating and is suitable for systems where small size, arc resistance, environmental immunity and/or reduced maintenance needs are important.
Watch the video below to learn more about medium-voltage, gas-insulated, arc-resistant switchgear.
- Arc-resistant to IEEE C37.20.7, up to 63 kA, 0.5 sec, accessibility type 2B
- Significantly reduced personal protective equipment (PPE) needs
- Single-phase design eliminates phase-to-phase faults insided the switchgear
- Vacuum interrupter - up to 30,000 mechanical operations
- Low-pressure SF6 gas-insulated for insulation only and not for interruption
- Voltage transformers with primary fused protection per NEC article 240.15(A) and 450.3(C)
- Main busbar expansion without shutdown via optional busbar expansion switch
- Compact - up to 75 percent smaller than traditional air-insulated switchgear
- Maintenance-free primary part
- Well-suited for contaminated environments
- Pair with Siemens protective relays to match any typical application
- Over 100,000 panels worldwide with more than 4,500 installed in North America
- Meets NEC visible disconnect requirement
- Meets or exceeds the latest IEEE and IEC standards
- UL or C-UL Listing available.
Types 8DA10 and 8DAB10 switchgear available as:
- Manual operation tool kit.
- Human Machine Interface (HMI).
1 On request. Consult factory.
2 Tested to ANSI/IEEE C37.20.7-2007 for arc-resistance type 2B at 40 kA for 0.5 seconds.
TechTopics is a series of papers that discuss issues of interest to users or specifiers of electrical equipment.
- No. 02 - Loss of vacuum
- No. 35 - Transient recovery voltage
- No. 37 - Low current switching capabilities
- No. 38 - Harmonic filter application
- No. 44 - Anatomy of a short circuit
- No. 53 - Use of SF6 gas in medium-voltage switchgear
- No. 57 - Arc flash hazard labels
- No. 70 - Arc-resistant switchgear accessibility types
- No. 79 - Working space required around electrical equipment
- No. 82 - Continuous current capability in ambient temperatures other than 40 °C
- No. 95 - Tie circuit breakers and out-of-phase applications
- No. 96 - Phase sequence versus phase arrangement
- No. 101 - Siemens medium-voltage gas-insulated switchgear bus differential protection
- No. 111 - SF6 gas and U.S. greenhouse gas emissions
- No. 113 - Preferred locations for current transformers
- No. 115 - Third-party listing/labeling and recognition
- No. 116 - Arc-resistant switchgear ‒ accessibility type C
- No. 119 - Momentary ratings – peak or rms?
- No. 120 - High-potential testing – current doesn’t matter!
- No. 121 - Ground return currents in gas-insulated switchgear
- Entire TechTopics catalog
Q: Can the circuit breaker interrupt if there is a leak and no SF6 gas is available?
A: Yes, the vacuum interrupters are independent of the SF6 gas and all the interruption occurs inside the vacuum interrupters. SF6 gas is only used for insulation.
Q: What is the probability of SF6 leakage?
A: The low leakage rate is possible as the normal pressure is 1.5 bar (22 psig) or less, as the SF6 gas is used only for insulation, not for interruption.
Q: What is medium-voltage gas-insulated switchgear?
Vacuum interruption technology with SF6 as an insulation medium
Over 1,000,000 Siemens vacuum interrupters manufactured. Circuit breakers are fixed mounted, which reduces floor space requirements and eliminates complexities of drawout construction.
Three-position selector switch allows extra security for isolation of load side during maintenance
Single-phase encapsulated, thus eliminating phase-to-phase faults
Enclosures are safe-to-touch from busbar housing to primary cables
Capacitive voltage indicators allow extra security for detection of voltage presence before performing maintenance
High-voltage components are encapsulated in SF6
All low-voltage components are installed outside of SF6
Current transformers (CTs) are outside of the high-voltage enclosure and thus not exposed to dielectric or thermal stress
Pressure gauges monitor SF6 compartments and contacts are available for sending alarm signals to SCADA system or annunciator
Gas leakage less than 0.1% per compartment per year
More compact than conventional air-insulated switchgear - up to 75% smaller depending upon voltage rating
Available in single (type 8DA10) and double (type 8DB10) busbar designs
Seismic capability up to UBC zone 4 (optional).
Q: When should medium-voltage, gas-insulated switchgear be used?
Ratings - up to 38 kV (42 kV on request), 2,500 A, 40 kA and 200 kV BIL
Reliability - virtually maintenance-free with recommended minor maintenance at 10-year intervals and major maintenance at 20-year intervals. Vacuum interrupter endurance is 30,000 mechanical operations.
Personnel security - MV GIS is an arc-resistant design design and is safe-to-touch from the busbar compartment to the power cables. All operations are performed in front of the switchgear.
Space savings - MV GIS is up to 75% smaller than conventional air-insulated switchgear depending upon the voltage rating that could result in a total cost saving in land and buildings.
Environmental problems - MV GIS is perfect for installation sites with dust, vermin, salt or a contaminated atmosphere. Available for installation in an outdoor power equipment center (PEC).
Altitude - MV GIS is insulated with SF6 instead of air and therefore is not required to be derated.
Flexibility - MV GIS can be customized to your needs. MV GIS is available in single-bus (type 8DA10) and a double-bus (type 8DB10) designs.
Grounding - MV GIS has grounding capabilities for both the power cables (standard) and the busbars (optional).