Sf 6 has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. Sulphur hexafluoride sf6 circuit breaker a circuit breaker in which sf 6 under pressure gas is used to extinguish the arc is called sf 6 circuit breaker. Sulphur hexafluoride article about sulphur hexafluoride. Advantages over other media include lower operating noise and no. The mechanical operating mechanism used is esh type with stored energy and free release which allows. Sf 6 gas has excellent insulating property and it has a high electronegativity.
A circuit breaker in which sulphur hexafluoride gas or sf 6 gas is used as the arc quinching medium, known as an sf6 circuit breaker. Sulphur hexafluoride, sf6, is a nontoxic, inert, insulating and cooling gas of high dielectric strength and thermal stability. This document provides the technical procedures for the analysis of sulfur hexafluoride sf. Sf6, the most potent greenhouse gas in existence, was banned for all applications in the eu in 2014 except in the electricity industry. Electrical breakdown of long gaps in sulfur hexafluoride. Catalog of guidelines and standards for the handling and.
Handling of sulfur hexafluoride gas central facilities. Sf6 circuit breakers construction, types and working. Abb library is a web tool for searching for documents related to abb products and services. Companies circuit breakers, sulphur hexafluoride sf6. Performing organizations names and addresses bureau of reclamation denver federal center po box 25007 denver co 802250007 8.
In addition to its many advantages in terms of technical properties, sf 6 has the disadvantage of having a very high global warming potential gwp. Gasco sulfur hexafluoride calibration gas 100 ppm balance nitrogen in a 103 liter steel disposable cylinder. A circuit breaker in which uses sulfur hexafluoride or sf6 gas as arc extinguished medium is known as sf6 circuit breaker. Test conducted at ornl indicate that vacuum conditions, as might be found in sfsub 6 circuit breakers prior to filling with sfsub 6, could lead to significant changes in calibration, resulting in erroneous readings.
The paper also provides the recommendations for change sf6 circuit breaker. An air circuit breaker for low voltage less than volts power distribution switchgear. Concept for sf6free transmission and distribution of. Outdoor sf6 circuit breaker type ohb instruction for storage, installation, service and maintenance. Sf6 is an inert gas, but decomposed components as a result of electrical arcing or naked flames are toxic and hazardous. The reason for the exemption, writes nicholas ottersbach, researcher, that there was no viable alternative. A circuit breaker in which the current carrying contacts operate in sulfur hexafluoride or sf6 gas is known as sf6 circuit breaker. Additionally, it is used for the filling of insulated windows and for the casting of magnesium. B sf6 an inert gas does not undergo any chemical reactions and thermally stable good arc quenching and insulating properties, 100 times more than air. Instead of oil, air, or a vacuum, a sulfur hexafluoride circuit breaker uses sulfur hexafluoride sf 6 gas to cool and quench the arc on opening a circuit.
Medium voltage mv is defined as 1kv to 36kv high voltage hv is defined as 36kv to 2kv. Sulphur hexafluoride is a greenhouse gas, and wilful venting to the atmosphere is illegal refer to section 9. Pdf electrical strength analysis of sf6 gas circuit breaker element. Sf6 is a very good dielectric material which can resist high potentials. Sf6 puffer type circuit breaker development work on circuit breakers using sulphur hexafluoride sf6 gas started in the 1950s and a few initial designs were made in early 1960s. All sf 6 gas shall be obtained through a central facility.
If moisture is able to infiltrate over time, arcing can occur. Comed and peco have approximately 200,000 lbs of sf6 in service within twopressure breakers, puffer breakers, circuit switchers, and gas insulating. Sulfur hexafluoride sf 6 is an inorganic, colorless, odorless, nonflammable, nontoxic but extremely potent greenhouse gas, and an excellent electrical insulator. Sf 6 is expensive and is also a powerful green house gas 20,000 times more potent than co 2. During operation of sf6 circuit breaker, this highly compressed gas is released through the arc in the breaker and collected to a relatively lowpressure reservoir and then it is pumped back to the highpressure reservoir for reutilizing. The excellent dielectric properties of sf6 gas helped in. Sulfur hexafluoride sf6 recovery generon pioneering. Fist 59, management and safe handling procedures for sulfur hexafluoride sf6 gas 5.
Typical for a nonpolar gas, it is poorly soluble in water but quite soluble in nonpolar. Hence, this gas also began to be used in circuit breaker as arc quenching medium. Sf6 gas is used as the arc quenching medium sulfur hexafluoride sf6 is an electronegative gas and has a strong tendency to absorb free electrons. The designated central facility is responsible for maintaining a log. Sf 6 sulphur hexafluoride gas has excellent dielectric, arc quenching, chemical and other physical properties which have proved its superiority over other arc quenching mediums such as oil or air. Sulfur hexafluoride circuit breakers protect electrical power stations and distribution systems by interrupting electric currents, when tripped by a protective relay. Sf6 circuit breaker sulfur hexafluoride circuit breaker. In an sf6 circuit breaker, sulphur hexafluoride gas is used as the arc quenching medium the sulphur hexafluoride gas sf6 is an electronegative gas and has a strong tendency to absorb free electrons. The catalog is divided into five summary tables corresponding to four industry categories and an other industries category followed by the complete and more detailed list of all references. The dielectric and other physical and chemical properties related to its lack of reactivity have led to the extensive use of sf 6 as an insulating medium in switching equipment e. It therefore warrants methodical and careful handling. Typical 245 kv dead tank circuit breakers using sf6 gas as. During short circuit fault or any other types of electrical fault these.
Its density is 5 times that of air and heat convection is. Circuit breaker a 2 pole miniature circuit breaker from wikipedia, the free encyclopedia a circuit breaker is an automaticallyoperated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Type medium voltage, breaking capacity 1 air break circuit. Identifying, quantifying and controlling emissions of. Authors bureau of reclamation hydroelectric research and technical services group denver, colorado 7. Sf6 circuit breaker advantages disadvantages applications. Each table includes the organizationauthor, title, date, and topics addressed for each.
Sulfur hexafluoride sf6 recycling program for out of. A circuit breaker is a protective device which can break the circuit automatically under the fault condition. It consists of current carrying contacts enclosed in a strong, weathertight earth metal tank and the tank is filled with transformer oil. It is a nontoxic, colourless and odourless inert gas. A circuit breaker in which the current carrying contacts operate in sulphur hexafluoride or sf6 gas is known as an sf6 circuit breaker. In particular, it prohibits the import, sale and use of new products containing fluorinated gases after 1 january 2006 and prohibits the. Sf6 properties, and use in mv and hv switchgear contents 1 introduction 1. Measurement of water vapor in sulphur hexafluoride, sf6. Sulphur hexafluoride sf6 is used as a switchgear interrupting medium from 1 to 800kv nonflammable arcquenching nontoxic. Gasco sulfur hexafluoride calibration gas 100 ppm balance air in a 600 liter aluminum disposable cylinder cga 590 connection. As sf 6 is heavier than air it displaces the oxygen in the air if it is inadvertently set free. Due to high electronegativity, it has a high affinity for absorbing free electrons.
Specification of technical grade sulphur hexafluoride sf6 for use in electrical equipment purposes legally binding document step out from the old to the newjawaharlal nehru invent a new india using knowledgesatyanarayan gangaram pitroda. This technique is the result of many years experience in sf6 technology and major research work. Sf 6 circuit breakers are made from 72550kv with interruption current of 20 to 63 ka and rated current of 1,200 to 12000 amps because of the properties of sf 6 gas such as excellent arc quenching, high electronegative nature, and excellent dielectric strength sf 6 circuit breakers are popular for high voltage applications and above. Worlds first sf 6 gas insulated substation was established in paris in the year of 1966.
Measurements at ornl were made on the kahn moisture sensor which doble engineering wants to evaluate for use in sfsub 6 circuit breakers. Handling and use of sulfur hexafluoride gas page 4 of 8 v. But according to ottersbach that is no longer the case. Sulphur hexa fluoride sf6 extra high voltage circuit. Hv circuit breaker type generator circuit breaker fkga8 generator circuit breaker i sc 210 ka u r 33 kv sf 6 circuit breaker designed for power plants from 700 to 1,500 mw it is equipped with a springoperated mechanism per pole. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset either manually or. Sulphur hexafluoride medium voltage circuit breakers launched into market from 1971. It combines the effect of thermal expansion with a rotating arc to create arc.
It is chemically inert, gaseous even at low temperature, non flammable, non toxic, non corrosive. Sf6 gas is used as an insulating medium in high kva breakers. Sulphur hexafluoride sf 6 is an excellent dielectric gas for high voltage applications. Application, advantages and disadvantages of oil, minimum oil, air blast, sulfur hexafluoride, vacuum circuit breaker. The authorisation thus given to the federal ministry of agriculture, forestry, environment and water management concerns prohibitions and restrictions affecting partially fluorinated and perfluorinated hydrocarbons and sulphur hexafluoride. Advantages over other media include lower operating noise and no emission. Since the 1980s, sulfur hexafluoride sf6 has been used extensively in the electricity transmission and distribution industry as an insulator and arc interrupter for high and medium voltage circuit breakers, switchgear and other electrical equipment.
In case of air blast and oil circuit breakers, the extinguishing force builds up relatively slowly after the moment of contact separation and hence the arc is usually extinguished after a few cycles of. Performance analysis of high voltage sf6 circuit breaker based on coupling computation of electricgas flow field. Sulfur hexafluoride sf 6 is a relatively nontoxic gas used in a number of applications for its inert qualities. Instead of oil, air, or a vacuum, a sulfur hexafluoride circuit breaker uses sulfur hexafluoride gas to cool and quench the arc on opening a circuit. Due to its high dielectric strength, it is particularly suited for application in high power circuit breakers as well as in highvoltage cables, transformers, and switchgears. Solvays sulphur hexafluoride is a non toxic, inert, insulating. Sulfur hexafluoride 100 2551624 ingredient name % cas number there are no additional ingredients present which, within the current knowledge of the supplier and in the. Use and handling of sulphur hexafluoride sf6 in high voltage switchgear and controlgear. This can lead to premature failure of the breaker, possibly with catastrophic results. Circuit breakers, sulphur hexafluoride sf6 circuit breakers, air break south korea. The comparison of arcextinguishing capability of sulfur.
The oil is both acts as an arc extinguishing medium and as an insulator between the live part and earth. A circuit breaker in which sf 6 under pressure gas is used to extinguish the arc is called sf 6 circuit breaker. Sf6 emissions reduction partnership exelon has participated in the sf6 emissions reduction partnership with u. The contacts of the breaker are opened in a highpressure flow sulphur hexafluoride sf6 gas and an arc is struck between them. The circuit breaker can make or break the circuit either manually or by remote control. Application, advantages and disadvantages of all types of. Gas circuit breaker gcb uses sulphurhexafluoride sf6 gas to quench the arc because of its high dielectric strength, unique arc quenching ability, excellent thermal stability and good thermal. Sulfur hexaflouride sf6 is an electronegative gas and has a strong tendency to absorb free electrons. Sulfur hexafluoride, sf 6, is used around the world as a dielectric medium for highvoltage circuit breakers, switchgear, and other electrical equipment. The circuit breaker credit amount is the amount the net tax bill on each type of property exceeds the property tax cap. Why do the sf 6 gases have an excellent heat transfer property. Circuit breaker dielectric strength current zero pure carbon dioxide priming.