Switchgear
Content
Switchgear - Wikipedia, the free encyclopedia
Page 1 of 8
Switchgear
From Wikipedia, the free encyclopedia
In an electric power system, switchgear is the combination
of electrical disconnect switches, fuses or circuit breakers
used to control, protect and isolate electrical equipment.
Switchgear is used both to de-energize equipment to allow
work to be done and to clear faults downstream. This type of
equipment is directly linked to the reliability of the electricity
supply.
The very earliest central power stations used simple open
knife switch, mounted on insulating panels of marble or
asbestos. Power levels and voltages rapidly escalated, making
opening manually operated switches too dangerous for
anything other than isolation of a de-energized circuit. Oilfilled equipment allowed arc energy to be contained and
safely controlled. By the early 20th century, a switchgear line
-up would be a metal-enclosed structure with electrically
operated switching elements, using oil circuit breakers.
Today, oil-filled equipment has largely been replaced by airblast, vacuum, or SF6 equipment, allowing large currents and
power levels to be safely controlled by automatic equipment.
High-voltage switchgear was invented at the end of the 19th
century for operating motors and other electric machines.[1]
The technology has been improved over time and can now be
High voltage switchgear
A section of a large switchgear panel,
in this case, used to control on-board
casino boat power generation.
used with voltages up to 1,100 kV.[2]
Typically, switchgears in substations are located on both the
high- and low-voltage sides of large power transformers. The
switchgear on the low-voltage side of the transformers may
be located in a building, with medium-voltage circuit
breakers for distribution circuits, along with metering,
control, and protection equipment. For industrial
applications, a transformer and switchgear line-up may be
combined in one housing, called a unitized substation (USS).
Contents
■ 1 History
■ 2 Housing
■ 3 Types
■ 3.1 Oil
■ 3.2 Air
■ 3.3 Gas
https://en.wikipedia.org/wiki/Switchgear
Tram switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 2 of 8
■ 3.4 Hybrid
■ 3.5 Vacuum
■ 3.6 Carbon dioxide (CO2)
■ 4 Classification
■ 5 Functions
■ 6 Safety
■ 7 See also
■ 8 References
■ 9 External links
This circuit breaker uses both SF6 and
History
air as insulation.
Switchgear is as old as electricity generation. The first
models were very primitive: all components were simply
fixed to a wall. Later they were mounted on wooden panels.
For reasons of fire protection, the wood was replaced by slate
or marble. This led to a further improvement, because the
switching and measuring devices could be attached to the
front, while the wiring was on the back.[3]
Housing
Switchgear for lower voltages may be entirely enclosed
within a building. For higher voltages (over about 66 kV),
switchgear is typically mounted outdoors and insulated by
air, although this requires a large amount of space. Gasinsulated switchgear saves space compared with air-insulated
equipment, although the equipment cost is higher. Oil
insulated switchgear presents an oil spill hazard.
Early switchgear (about 1910)
Switches may be manually operated or have motor drives to
allow for remote control.
Types
A switchgear may be a simple open-air isolator switch or it may be insulated by some other
substance. An effective although more costly form of switchgear is the gas-insulated switchgear
(GIS), where the conductors and contacts are insulated by pressurized sulfur hexafluoride gas (SF6).
Other common types are oil or vacuum insulated switchgear.
The combination of equipment within the switchgear enclosure allows them to interrupt fault
currents of thousands of amps. A circuit breaker (within a switchgear enclosure) is the primary
component that interrupts fault currents. The quenching of the arc when the circuit breaker pulls
apart the contacts open (disconnects the circuit) requires careful design. Circuit breakers fall into
these five types:
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 3 of 8
Oil
Oil circuit breakers rely upon vaporization of some of the oil
to blast a jet of oil along the path of the arc. The vapor
released by the arcing consists of hydrogen gas.
Air
Air circuit breakers may use compressed air (puff) or the
magnetic force of the arc itself to elongate the arc. As the
length of the sustainable arc is dependent on the available
voltage, the elongated arc will eventually exhaust itself.
Alternatively, the contacts are rapidly swung into a small
sealed chamber, the escaping of the displaced air thus
blowing out the arc.
Circuit breakers are usually able to terminate all current flow very quickly: typically between 30 ms
and 150 ms depending upon the age and construction of the device.
Gas
Gas (SF6) circuit breakers sometimes stretch the arc using a magnetic field, and then rely upon the
dielectric strength of the SF6 gas to quench the stretched arc.
Hybrid
Hybrid switchgear is a type which combines the components of traditional air-insulated switchgear
(AIS) and SF6 gas-insulated switchgear (GIS) technologies. It is characterized by a compact and
modular design, which encompasses several different functions in one module.
Vacuum
Circuit breakers with vacuum interrupters have minimal arcing characteristics (as there is nothing to
ionize other than the contact material), so the arc quenches when it is stretched by a small amount
(<2–8 mm). Near zero current the arc is not hot enough to maintain a plasma, and current ceases; the
gap can then withstand the rise of voltage. Vacuum circuit breakers are frequently used in modern
medium-voltage switchgear to 40,500 volts. Unlike the other types, they are inherently unsuitable for
interrupting DC faults.
Carbon dioxide (CO2)
Breakers that use carbon dioxide as the insulating and arc extinguishing medium work on the same
principles as a sulfur hexafluoride (SF6) breaker. Because SF6 is a greenhouse gas more potent than
CO2, by switching from SF6 to CO2 it is possible to reduce the greenhouse gas emissions by 10 tons
during the product lifecycle.[4]
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 4 of 8
Classification
Several different classifications of switchgear can be made:[5]
■ By the current rating.
■ By interrupting rating (maximum short circuit current kAIC that the device can safely
interrupt)
■ Circuit breakers can open and close on fault currents
■ Load-break/Load-make switches can switch normal system load currents
■ Isolators are off load disconnectors which are to be operated after Circuit Breakers, or
else if the load current is very small
■ By voltage class:
■ Low voltage (less than 1 kV AC)
■ Medium voltage (1 kV AC through to approximately 75 kV AC)
■ High voltage (75 kV to about 230 kV AC)
■ Extra high voltage, ultra high voltage (more than 230 kV)
■ By insulating medium:
■ Air
■ Gas (SF6 or mixtures)
■ Oil
■ Vacuum
■ Carbon dioxide (CO2)
■ By construction type:
■ Indoor (further classified by IP (Ingress Protection) class or NEMA enclosure type)
■ Outdoor
■ Industrial
■ Utility
■ Marine
■ Draw-out elements (removable without many tools)
■ Fixed elements (bolted fasteners)
■ Live-front
■ Dead-front
■ Open
■ Metal-enclosed
■ Metal-clad
■ Arc-resistant
■ By IEC degree of internal separation[6]
■ No Separation (Form 1)
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 5 of 8
■ Busbars separated from functional units (Form 2a, 2b, 3a, 3b, 4a, 4b)
■ Terminals for external conductors separated from busbars (Form 2b, 3b, 4a, 4b)
■ Terminals for external conductors separated from functional units but not from each
other (Form 3a, 3b)
■ Functional units separated from each other (Form 3a, 3b, 4a, 4b)
■ Terminals for external conductors separated from each other (Form 4a, 4b)
■ Terminals for external conductors separate from their associated functional unit (Form
4b)
■ By interrupting device:
■ Fuses
■ Air Circuit Breaker
■ Minimum Oil Circuit Breaker
■ Oil Circuit Breaker
■ Vacuum Circuit Breaker
■ Gas (SF6) Circuit breaker
■ CO2 Circuit Breaker
■ By operating method:
■ Manually operated
■ Motor/stored energy operated
■ Solenoid operated
■ By type of current:
■ Alternating current
■ Direct current
■ By application:
■ Transmission system
■ Distribution
■ By purpose
■ Isolating switches (disconnectors)
■ Load-break switches.[7][8]
■ Grounding (earthing) switches
A single line-up may incorporate several different types of devices, for example, air-insulated bus,
vacuum circuit breakers, and manually operated switches may all exist in the same row of cubicles.
Ratings, design, specifications and details of switchgear are set by a multitude of standards. In North
America mostly IEEE and ANSI standards are used, much of the rest of the world uses IEC
standards, sometimes with local national derivatives or variations.
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 6 of 8
Functions
One of the basic functions of switchgear is protection, which is interruption of short-circuit and
overload fault currents while maintaining service to unaffected circuits. Switchgear also provides
isolation of circuits from power supplies. Switchgear is also used to enhance system availability by
allowing more than one source to feed a load.
Safety
To help ensure safe operation sequences of switchgear, trapped key interlocking provides predefined
scenarios of operation. For example, if only one of two sources of supply are permitted to be
connected at a given time, the interlock scheme may require that the first switch must be opened to
release a key that will allow closing the second switch. Complex schemes are possible.
Indoor switchgear can also be type tested for internal arc containment (e.g., IEC 62271-200). This
test is important for user safety as modern switchgear is capable of switching large currents.[9]
Switchgear is often inspected using thermal imaging to assess the state of the system and predict
failures before they occur. Other methods include partial discharge (PD) testing, using either fixed or
portable testers, and acoustic emission testing using surface-mounted transducers (for oil equipment)
or ultrasonic detectors used in outdoor switchyards. Temperature sensors fitted to cables to the
switchgear can permanently monitor temperature build-up. SF6 equipment is invariably fitted with
alarms and interlocks to warn of loss of pressure, and to prevent operation if the pressure falls too
low.
The increasing awareness of dangers associated with high fault levels has resulted in network
operators specifying closed-door operations for earth switches and racking breakers. Many European
power companies have banned operators from switch rooms while operating. Remote racking
systems are available which allow an operator to rack switchgear from a remote location without the
need to wear a protective arc flash hazard suit.
245 kV circuit breaker in air insulated substation 420 kV gas insulated switchgear
...
See also
■ Arc flash
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 7 of 8
■ Circuit breaker
■ Disconnector
■ Electrical safety
■ Electric arc
■ High voltage
■ Remote racking system
■ Short circuit
References
1. British Pattern GB 20069 Improvements in Apparatus for Controlling the Application or Use of Electric
Currents of High Tension and Great Quantity in 1893 (http://v3.espacenet.com/origdoc?
DB=EPODOC&IDX=GB189320069&F=0&QPN=GB189320069), on espacenet.com
2. Lin Jiming et al., Transient characteristics of 1 100 kV circuit-breakers, International Symposium on
International Standards for Ultra High Voltage, Beijing, Juillet 2007.
3. (German) Allgemeine Elektricitäts-Gesellschaft (ed) AEG Hilfsbuch für elektrische Licht- und
Kraftanlagen 6th Ed., W. Girardet, Essen 1953
4. "Switzerland : ABB breaks new ground with environment friendly high-voltage circuit
breaker." (http://www.thefreelibrary.com/Switzerland+%
3A+ABB+breaks+new+ground+with+environment+friendly...-a0300987882). Retrieved 9 July 2013.
5. Robert W. Smeaton (ed) Switchgear and Control Handbook 3rd Ed., McGraw Hill, New York 1997
ISBN 0-07-058451-6
6. IEC Standard EN 60439 part 1 Table 6A
7. (French) Norme CEI 60265-1 Interrupteurs pour tension assignée supérieure à 1 kV et inférieure à 52
kV (http://domino.iec.ch/preview/info_iec60265-1{ed3.0}b.pdf)
8. (French) Norme CEI 60265-2 Interrupteurs pour tension assignée supérieure à 52 kV
(http://domino.iec.ch/preview/info_iec60265-2{ed1.0}b.img.pdf)
9. https://www.energy.siemens.com/cms/00000013/aune/Documents/Medium%20Voltage%20Arc%
20Fault%20Containment.pdf
External links
■ The basic functions of LV switchgear
(http://www.electrical-
Wikimedia Commons has
media related to
Switchgear.
installation.org/wiki/The_basic_functions_of_LV_switchgear)
■ (English) IEC TC17: Switchgear & ControlgearTechnical Committee
(http://prabhatpower.com), on tc17.iec.ch
■ (English) IEEE Switchgear Committee (http://www.ewh.ieee.org/soc/pes/switchgear/), on
ewh.ieee.org
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 8 of 8
■ (German) Course ETHZ, handouts_2.pdf
(http://www.eeh.ee.ethz.ch/downloads/academics/courses/227-0122-00-handouts_2.pdf), on
eeh.ee.ethz.ch
Retrieved from "http://en.wikipedia.org/w/index.php?title=Switchgear&oldid=658388306"
Categories: Electric power systems components Electric power infrastructure Electric power
■ This page was last modified on 22 April 2015, at 14:14.
■ Text is available under the Creative Commons Attribution-ShareAlike License; additional
terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit
organization.
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Page 1 of 8
Switchgear
From Wikipedia, the free encyclopedia
In an electric power system, switchgear is the combination
of electrical disconnect switches, fuses or circuit breakers
used to control, protect and isolate electrical equipment.
Switchgear is used both to de-energize equipment to allow
work to be done and to clear faults downstream. This type of
equipment is directly linked to the reliability of the electricity
supply.
The very earliest central power stations used simple open
knife switch, mounted on insulating panels of marble or
asbestos. Power levels and voltages rapidly escalated, making
opening manually operated switches too dangerous for
anything other than isolation of a de-energized circuit. Oilfilled equipment allowed arc energy to be contained and
safely controlled. By the early 20th century, a switchgear line
-up would be a metal-enclosed structure with electrically
operated switching elements, using oil circuit breakers.
Today, oil-filled equipment has largely been replaced by airblast, vacuum, or SF6 equipment, allowing large currents and
power levels to be safely controlled by automatic equipment.
High-voltage switchgear was invented at the end of the 19th
century for operating motors and other electric machines.[1]
The technology has been improved over time and can now be
High voltage switchgear
A section of a large switchgear panel,
in this case, used to control on-board
casino boat power generation.
used with voltages up to 1,100 kV.[2]
Typically, switchgears in substations are located on both the
high- and low-voltage sides of large power transformers. The
switchgear on the low-voltage side of the transformers may
be located in a building, with medium-voltage circuit
breakers for distribution circuits, along with metering,
control, and protection equipment. For industrial
applications, a transformer and switchgear line-up may be
combined in one housing, called a unitized substation (USS).
Contents
■ 1 History
■ 2 Housing
■ 3 Types
■ 3.1 Oil
■ 3.2 Air
■ 3.3 Gas
https://en.wikipedia.org/wiki/Switchgear
Tram switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 2 of 8
■ 3.4 Hybrid
■ 3.5 Vacuum
■ 3.6 Carbon dioxide (CO2)
■ 4 Classification
■ 5 Functions
■ 6 Safety
■ 7 See also
■ 8 References
■ 9 External links
This circuit breaker uses both SF6 and
History
air as insulation.
Switchgear is as old as electricity generation. The first
models were very primitive: all components were simply
fixed to a wall. Later they were mounted on wooden panels.
For reasons of fire protection, the wood was replaced by slate
or marble. This led to a further improvement, because the
switching and measuring devices could be attached to the
front, while the wiring was on the back.[3]
Housing
Switchgear for lower voltages may be entirely enclosed
within a building. For higher voltages (over about 66 kV),
switchgear is typically mounted outdoors and insulated by
air, although this requires a large amount of space. Gasinsulated switchgear saves space compared with air-insulated
equipment, although the equipment cost is higher. Oil
insulated switchgear presents an oil spill hazard.
Early switchgear (about 1910)
Switches may be manually operated or have motor drives to
allow for remote control.
Types
A switchgear may be a simple open-air isolator switch or it may be insulated by some other
substance. An effective although more costly form of switchgear is the gas-insulated switchgear
(GIS), where the conductors and contacts are insulated by pressurized sulfur hexafluoride gas (SF6).
Other common types are oil or vacuum insulated switchgear.
The combination of equipment within the switchgear enclosure allows them to interrupt fault
currents of thousands of amps. A circuit breaker (within a switchgear enclosure) is the primary
component that interrupts fault currents. The quenching of the arc when the circuit breaker pulls
apart the contacts open (disconnects the circuit) requires careful design. Circuit breakers fall into
these five types:
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 3 of 8
Oil
Oil circuit breakers rely upon vaporization of some of the oil
to blast a jet of oil along the path of the arc. The vapor
released by the arcing consists of hydrogen gas.
Air
Air circuit breakers may use compressed air (puff) or the
magnetic force of the arc itself to elongate the arc. As the
length of the sustainable arc is dependent on the available
voltage, the elongated arc will eventually exhaust itself.
Alternatively, the contacts are rapidly swung into a small
sealed chamber, the escaping of the displaced air thus
blowing out the arc.
Circuit breakers are usually able to terminate all current flow very quickly: typically between 30 ms
and 150 ms depending upon the age and construction of the device.
Gas
Gas (SF6) circuit breakers sometimes stretch the arc using a magnetic field, and then rely upon the
dielectric strength of the SF6 gas to quench the stretched arc.
Hybrid
Hybrid switchgear is a type which combines the components of traditional air-insulated switchgear
(AIS) and SF6 gas-insulated switchgear (GIS) technologies. It is characterized by a compact and
modular design, which encompasses several different functions in one module.
Vacuum
Circuit breakers with vacuum interrupters have minimal arcing characteristics (as there is nothing to
ionize other than the contact material), so the arc quenches when it is stretched by a small amount
(<2–8 mm). Near zero current the arc is not hot enough to maintain a plasma, and current ceases; the
gap can then withstand the rise of voltage. Vacuum circuit breakers are frequently used in modern
medium-voltage switchgear to 40,500 volts. Unlike the other types, they are inherently unsuitable for
interrupting DC faults.
Carbon dioxide (CO2)
Breakers that use carbon dioxide as the insulating and arc extinguishing medium work on the same
principles as a sulfur hexafluoride (SF6) breaker. Because SF6 is a greenhouse gas more potent than
CO2, by switching from SF6 to CO2 it is possible to reduce the greenhouse gas emissions by 10 tons
during the product lifecycle.[4]
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 4 of 8
Classification
Several different classifications of switchgear can be made:[5]
■ By the current rating.
■ By interrupting rating (maximum short circuit current kAIC that the device can safely
interrupt)
■ Circuit breakers can open and close on fault currents
■ Load-break/Load-make switches can switch normal system load currents
■ Isolators are off load disconnectors which are to be operated after Circuit Breakers, or
else if the load current is very small
■ By voltage class:
■ Low voltage (less than 1 kV AC)
■ Medium voltage (1 kV AC through to approximately 75 kV AC)
■ High voltage (75 kV to about 230 kV AC)
■ Extra high voltage, ultra high voltage (more than 230 kV)
■ By insulating medium:
■ Air
■ Gas (SF6 or mixtures)
■ Oil
■ Vacuum
■ Carbon dioxide (CO2)
■ By construction type:
■ Indoor (further classified by IP (Ingress Protection) class or NEMA enclosure type)
■ Outdoor
■ Industrial
■ Utility
■ Marine
■ Draw-out elements (removable without many tools)
■ Fixed elements (bolted fasteners)
■ Live-front
■ Dead-front
■ Open
■ Metal-enclosed
■ Metal-clad
■ Arc-resistant
■ By IEC degree of internal separation[6]
■ No Separation (Form 1)
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 5 of 8
■ Busbars separated from functional units (Form 2a, 2b, 3a, 3b, 4a, 4b)
■ Terminals for external conductors separated from busbars (Form 2b, 3b, 4a, 4b)
■ Terminals for external conductors separated from functional units but not from each
other (Form 3a, 3b)
■ Functional units separated from each other (Form 3a, 3b, 4a, 4b)
■ Terminals for external conductors separated from each other (Form 4a, 4b)
■ Terminals for external conductors separate from their associated functional unit (Form
4b)
■ By interrupting device:
■ Fuses
■ Air Circuit Breaker
■ Minimum Oil Circuit Breaker
■ Oil Circuit Breaker
■ Vacuum Circuit Breaker
■ Gas (SF6) Circuit breaker
■ CO2 Circuit Breaker
■ By operating method:
■ Manually operated
■ Motor/stored energy operated
■ Solenoid operated
■ By type of current:
■ Alternating current
■ Direct current
■ By application:
■ Transmission system
■ Distribution
■ By purpose
■ Isolating switches (disconnectors)
■ Load-break switches.[7][8]
■ Grounding (earthing) switches
A single line-up may incorporate several different types of devices, for example, air-insulated bus,
vacuum circuit breakers, and manually operated switches may all exist in the same row of cubicles.
Ratings, design, specifications and details of switchgear are set by a multitude of standards. In North
America mostly IEEE and ANSI standards are used, much of the rest of the world uses IEC
standards, sometimes with local national derivatives or variations.
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 6 of 8
Functions
One of the basic functions of switchgear is protection, which is interruption of short-circuit and
overload fault currents while maintaining service to unaffected circuits. Switchgear also provides
isolation of circuits from power supplies. Switchgear is also used to enhance system availability by
allowing more than one source to feed a load.
Safety
To help ensure safe operation sequences of switchgear, trapped key interlocking provides predefined
scenarios of operation. For example, if only one of two sources of supply are permitted to be
connected at a given time, the interlock scheme may require that the first switch must be opened to
release a key that will allow closing the second switch. Complex schemes are possible.
Indoor switchgear can also be type tested for internal arc containment (e.g., IEC 62271-200). This
test is important for user safety as modern switchgear is capable of switching large currents.[9]
Switchgear is often inspected using thermal imaging to assess the state of the system and predict
failures before they occur. Other methods include partial discharge (PD) testing, using either fixed or
portable testers, and acoustic emission testing using surface-mounted transducers (for oil equipment)
or ultrasonic detectors used in outdoor switchyards. Temperature sensors fitted to cables to the
switchgear can permanently monitor temperature build-up. SF6 equipment is invariably fitted with
alarms and interlocks to warn of loss of pressure, and to prevent operation if the pressure falls too
low.
The increasing awareness of dangers associated with high fault levels has resulted in network
operators specifying closed-door operations for earth switches and racking breakers. Many European
power companies have banned operators from switch rooms while operating. Remote racking
systems are available which allow an operator to rack switchgear from a remote location without the
need to wear a protective arc flash hazard suit.
245 kV circuit breaker in air insulated substation 420 kV gas insulated switchgear
...
See also
■ Arc flash
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 7 of 8
■ Circuit breaker
■ Disconnector
■ Electrical safety
■ Electric arc
■ High voltage
■ Remote racking system
■ Short circuit
References
1. British Pattern GB 20069 Improvements in Apparatus for Controlling the Application or Use of Electric
Currents of High Tension and Great Quantity in 1893 (http://v3.espacenet.com/origdoc?
DB=EPODOC&IDX=GB189320069&F=0&QPN=GB189320069), on espacenet.com
2. Lin Jiming et al., Transient characteristics of 1 100 kV circuit-breakers, International Symposium on
International Standards for Ultra High Voltage, Beijing, Juillet 2007.
3. (German) Allgemeine Elektricitäts-Gesellschaft (ed) AEG Hilfsbuch für elektrische Licht- und
Kraftanlagen 6th Ed., W. Girardet, Essen 1953
4. "Switzerland : ABB breaks new ground with environment friendly high-voltage circuit
breaker." (http://www.thefreelibrary.com/Switzerland+%
3A+ABB+breaks+new+ground+with+environment+friendly...-a0300987882). Retrieved 9 July 2013.
5. Robert W. Smeaton (ed) Switchgear and Control Handbook 3rd Ed., McGraw Hill, New York 1997
ISBN 0-07-058451-6
6. IEC Standard EN 60439 part 1 Table 6A
7. (French) Norme CEI 60265-1 Interrupteurs pour tension assignée supérieure à 1 kV et inférieure à 52
kV (http://domino.iec.ch/preview/info_iec60265-1{ed3.0}b.pdf)
8. (French) Norme CEI 60265-2 Interrupteurs pour tension assignée supérieure à 52 kV
(http://domino.iec.ch/preview/info_iec60265-2{ed1.0}b.img.pdf)
9. https://www.energy.siemens.com/cms/00000013/aune/Documents/Medium%20Voltage%20Arc%
20Fault%20Containment.pdf
External links
■ The basic functions of LV switchgear
(http://www.electrical-
Wikimedia Commons has
media related to
Switchgear.
installation.org/wiki/The_basic_functions_of_LV_switchgear)
■ (English) IEC TC17: Switchgear & ControlgearTechnical Committee
(http://prabhatpower.com), on tc17.iec.ch
■ (English) IEEE Switchgear Committee (http://www.ewh.ieee.org/soc/pes/switchgear/), on
ewh.ieee.org
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
Switchgear - Wikipedia, the free encyclopedia
Page 8 of 8
■ (German) Course ETHZ, handouts_2.pdf
(http://www.eeh.ee.ethz.ch/downloads/academics/courses/227-0122-00-handouts_2.pdf), on
eeh.ee.ethz.ch
Retrieved from "http://en.wikipedia.org/w/index.php?title=Switchgear&oldid=658388306"
Categories: Electric power systems components Electric power infrastructure Electric power
■ This page was last modified on 22 April 2015, at 14:14.
■ Text is available under the Creative Commons Attribution-ShareAlike License; additional
terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit
organization.
https://en.wikipedia.org/wiki/Switchgear
4/24/2015
