Siemens Gas-insulated switchgear User Manual
Gas-insulated switchgear
up to 145 kV, 40 kA, 3150 A
type series 8DN8
Answers for energy.
Connecting environment-friendly wind
energy to the grid with compact 8DN8 GIS
in switchgear building
Benefiting from experience
Bay control systems in ergonomically
arranged local control cabinet
8DN8 switchgear up to 145 kV,
outgoing cable bay
Our 8D series of gas-insulated switchgear represents
a highly successful product concept.
Since its introduction in 1968, Siemens has installed
more than 24,000 bays worldwide. A total of well
over 285,000 years of bay operation have since been
recorded.
Intensive research work, many years of system
experience, and continuous further development of
the first system types have ultimately led to today’s
generation of gas-insulated, metal-enclosed
switchgear – a world leader when it comes to
economic efficiency
high reliability
long service life
safe encapsulation
very high degree of gas-tightness
low life cycle and maintenance costs
easy access and ergonomic design
high availability
reliable operation even under extreme
environmental conditions
2 Siemens AG, Energy Sector, gas-insulated switchgear type series 8DN8
Area required
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[%]
90
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1968 Year 2009
Continuous further development has reduced the footprint required for 145-kV GIS
to only 25% of the first designs in 1968
Our type series 8DN8 switchgear for all voltage levels from 72.5 kV to 145 kV represents one of the
most compact systems of its kind available worldwide, and meets all of today’s requirements for modern, pioneering switchgear in terms of efficiency and
economy. Its space-saving design and its low weight
help make this switchgear extremely economical.
Since the levels of noise and field emission (EMC)
are extremely low, it is possible to easily integrate
8DN8 switchgear even in sensitive environments,
residential quarters, and city centers. They feature
high energy efficiency over the entire process
chain – from production and commissioning to
re cycling – and meets all current requirements for
environmentally compatible high-voltage switchgear.
8DN8 switchgear for 72.5 kV single
busbar arrangement
Switchgear type series 8DN8 145 kV combines technical expertise with all standards and advantages of
the Siemens 8D type series. It also offers a number
of distinct advantages:
Rapid availability thanks to time-saving delivery
and installation concepts
Independence from atmospheric and external
influences
Suitability for indoor and outdoor installation
Convincingly space-saving system configurations
(e.g. H configuration, 1½ breaker, ring, etc.)
High flexibility of switchgear arrangement for
optimized system management
Adaptable to all predecessor models of the same
voltage level
Switchgear type series 8DN8 72.5 kV corresponds to
switchgear 8DN8 145 kV with regard to construction
and technical design but it is significantly smaller.
The extremely small component dimensions allow it
to be deployed wherever space is at a premium.
3Siemens AG, Energy Sector, gas-insulated switchgear type series 8DN8
The 8DN8 allows a high degree of versatility in
switchgear layout thanks to its modular construction
The innovative design of the cast resin bushings allows
maximum flexibility in the design of bays and for installation
and service work
Flexible due to modular design
A fundamental feature of our gas-insulated switchgear is the high degree of versatility made possible
by its modular system. Depending on their respective functions, the components are housed either
individually and/or combined in pressure-resistant,
gas-tight enclosures. With a remarkably small number of active and passive modules, all customary
bus schemes are possible. Standard adapters
ensure compatibility with all predecessor models of
the same voltage level.
Three-phase enclosures are used for type series
8DN8 switchgear in order to achieve extremely low
com ponent dimensions. This concept allows a very
compact design with minimum space requirement.
The ergonomic modular principle makes for easy
access to control elements.
Aluminum is used for the enclosure. This guarantees
freedom from corrosion and ensures lightweight
equipment. The use of modern construction
methods and casting techniques makes it possible to
optimize the enclosure’s dielectric and mechanical
characteristics. The low bay weight ensures minimal
floor loading and eliminates the need for complex
foundations.
All the modules are connected to one another by
means of flanges. The gas-tightness of the flange
connections is assured by O-ring seals that have
been proven in operation since 1968.
Temperature-related changes in the length of
conductors are compensated by coupling contacts.
Where necessary, the joints are accessible via
openings sealed with gas-tight covers. Sulfur
hexafluoride (SF
) is used as the insulating and
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arc-quenching medium. It is contained in an
extremely gas-tight enclosure so that it cannot
pollute the environment.
Gas-tight bushings allow subdivision of the bay
into a number of separate gas compartments, each
of which is provided with its own gas monitoring
equipment. The static filters in the gas compartments absorb moisture and decomposition products.
The use of rupture diaphragms reliably prevents
shattering of the enclosure in the case of buildup of
abnormally high pressure. Diverter nozzles on the
rupture diaphragms ensure that the gas is expelled
in a defined direction in the event of bursting,
thus ensuring that the operating personnel are not
endangered.
4 Siemens AG, Energy Sector, gas-insulated switchgear type series 8DN8
Three-phase enclosure allows compact design:
8ND8 145 kV, cable bay with double busbar
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1. Integrated local control cubicle
2. Support for control cubicle
3. Current transformer
4. Busbar II with disconnector and
earthing switch
5. Interrupter unit of the circuit-breaker
6. Busbar I with disconnector and
earthing switch
7. Stored-energy spring mechanism
with circuit-breaker control unit
8. Voltage transformer
9. High-speed earthing switch
10. Outgoing feeder module with
disconnector and earthing switch
11. Cable sealing end
Variations are possible with switchgear type series 72.5 kV
Siemens AG, Energy Sector, gas-insulated switchgear type series 8DN8
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Circuit-breaker module
The central element of the gas-insulated switchgear
is the three-pole encapsulated circuit breaker
comprising the following two main components:
interrupter unit
operating mechanism
The design of the interrupter unit and of the storedenergy spring mechanism is based on proven and in
most cases identical designs which have often been
used for outdoor switchgear installations world wide.
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1. Trip coil CLOSE
2. Cam plate
3. Corner gears
4. Connecting rod
5. Connecting rod for closing
spring
6. Connecting rod for opening
spring
7. Closing spring
8. Emergency hand crank
Circuit-breaker module
1
2
9. Charging gear
10. Charging shaft
11. Roller lever
12. Damper (for closing)
13. Operating shaft
14. Damper (for opening)
15. Trip coil OPEN
16. Drive mechanism housing
17. Opening spring
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Operating mechanism
The stored-energy spring mechanism provides the
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force for opening and closing the circuit-breaker.
It is installed in a compact corrosion-free aluminum
housing. The closing spring and the opening spring
are arranged in order to ensure good visibility within
the drive unit. The entire drive unit is completely
isolated from the SF
gas compartments. Roller
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bearings and a maintenance-free spring mechanism
ensure decades of reliable operation.
Proven design principles of Siemens circuit-breakers
are used, such as vibration-isolated latches and
load-free isolation of the charging mechanism. The
operating mechanism offers the following
advantages:
defined switching position which is securely main-
tained even if the auxiliary power supply fails
tripping is possible irrespective of the status of the
closing spring
high number of mechanical operations
low number of mechanical parts
compact design
choice of single-pole or common drive design.
The single-pole version allows single-pole automatic reclosing.
Siemens AG, Energy Sector, gas-insulated switchgear type series 8DN8
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Variations are possible with switchgear type series 72.5 kV
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