Gas-Insulated Switchgear
Types 8DA10 (single bus) and 8DB10 (double bus) up to 38 kV, 40 kA, 200 kV BIL
Types 8DA10 and 8DB10 (up to 38 kV) Switchgear
Description
Description
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.
Technical Data
| Rated Maximum Voltage | kV | 15.5 | 27.0 | 38.0 | 421 |
| Rated Continuous Current of Main Bus (Maximum) | A | 4,000 | 4,000 | 4,000 | 4,000 |
| Rated Continuous Current of Circuit Breakers (Maximum) | A | 2,500 | 2,500 | 2,500 | 2,500 |
| Rated Lightning Impulse Withstand Voltage | kA peak | 95 | 125 | 170; 2001 | 185; 2001 |
| Power Frequency Withstand Voltage (One Minute) | kV | 36 | 60 | 80 | 80 |
| Frequency | Hz | 60 | 60 | 60 | 60 |
| Short-Circuit Interrupting Current (Maximum) | kA | Up to 40 | Up to 40 | Up to 40 | Up to 40 |
| Short-Time Withstand Current, 3 s (Maximum) | kA | Up to 40 | Up to 40 | Up to 40 | Up to 40 |
| Short-Circuit Making Curernt (Close and Latch) (Maximum) | kA peak | Up to 104 | Up to 104 | Up to 104 | Up to 104 |
| Peak Withstand Current (Maximum) | kA peak | Up to 104 | Up to 104 | Up to 104 | Up to 104 |
Footnotes:
[1] On request. Please consult factory.
Features
Features
Features include:
- Low pressure SF6 gas-insulated for insulation only and not for interruption
- Tested for arc-resistance to ANSI/IEEE C37.20.7-2007, type 2B
- Single-phase design eliminates phase-to-phase faults inside the switchgear
- Significantly reduced PPE needs
- Single-bus (type 8DA10) or double-bus (type 8DB10) configurations available
- Vacuum interrupter - up to 30,000 mechanical operations
- Well suited for contaminated environments
- Compact - up to 80% smaller than air-insulated switchgear
- 20-year internal maintenance cycle
- Meets IEEE and IEC standards
- Meets NEC visible disconnect requirement
- UL-or C-UL Listing available (consult factory)
- Seismic capability up to UBC zone 4 (optional)
- Pair with Siemens protective relays to match any typical application
- Front access design - rear access normally not necessary
- Disconnector (isolator) switch for line- or load-side (optional)
- Voltage transformers with disconnector switch and primary fuses available
- Plug-in voltage transformers fused and non-fused (optional)
- Plug-in surge arresters (optional)
- Power equipment center (PEC) configurations available for outdoor applications
- Locally trained factory personnel in the U.S. available for start-up or maintenance
- Over 55,000 panels installed worldwide with more than 2,200 installed in the U.S.
What is Medium-Voltage Gas-Insulated Switchgear and When Should it be Used?
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
- Arc-resistant design
- More compact than conventional switchgear - up to 80% smaller depending upon voltage rating
- Available in single (type 8DA10) and double (type 8DB10) busbar designs
- Seismic capability up to UBC zone 4 (optional)
- UL or C-UL Listing available
- More than 55,000 panels installed worldwide with more than 2,200 installed in the U.S.
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 80% smaller than conventional air-insulated switchgear depending upon the voltage rating that could result in a total cost saving in land and buildings. At 38 kV, 8DA10 MV GIS is 2' wide x 5' deep x 7' high and weighs approximately 1,600 lbs.
- 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).
Frequently Asked Questions
Frequently Asked Questions
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.
