US3569651A - Circuit breaker having pressurized liquified gas continuously maintained above instantaneous vapor pressure - Google Patents

Circuit breaker having pressurized liquified gas continuously maintained above instantaneous vapor pressure Download PDF

Info

Publication number
US3569651A
US3569651A US867959A US86795969A US3569651A US 3569651 A US3569651 A US 3569651A US 867959 A US867959 A US 867959A US 86795969 A US86795969 A US 86795969A US 3569651 A US3569651 A US 3569651A
Authority
US
United States
Prior art keywords
gas
circuit breaker
accumulator
liquefied
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US867959A
Other languages
English (en)
Inventor
Jean Louis Gratzmuller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3569651A publication Critical patent/US3569651A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/28—Power arrangements internal to the switch for operating the driving mechanism
    • H01H33/30—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator
    • H01H33/34—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator hydraulic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
    • H01H33/22—Selection of fluids for arc-extinguishing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/008—Pedestal mounted switch gear combinations

Definitions

  • a circuit breaker having a circuit interrupting chamber containing a liquefied dielectric gas with a fixed con [54] PSRESSURIZED tact member disposed so as to lie in the liquefied gas and a INSTANTANEOUSUVAU S E E movable contact member disposed in the chamber so as to 11 9 D PDR R s URE have its contact making surface within the liquefied gas for all of its positions relative to the fixed contact, and having means, [52] US. Cl.
  • This invention is for improvements in or relating to electric circuit breakers.
  • circuit breakers On the basis of the insulating fluid in which the circuit is broken, the known kinds of circuit breakers can be divided into two main kinds with rupturing properties compatible with the ever increasing short circuit powers of highand mediumvoltage networks. These two kinds are:
  • oil circuit breakers containing either a large volume of oil, as in US. practice, or a reduced volume of oil as in European practice, and
  • gas circuit breakers such as air blast circuit breakers and more recently sulfur hexafluoride (SF6) circuit breakers.
  • This invention relates to circuit breakers using a novel dielectric agent for arc extinction.
  • the invention relates to a circuit breaker wherein the insulating fluid in which the arc is quenched is a liquefiable dielectric gas kept liquid, at least in the circuit breaker rupture chamber, at normal outside ambient temperatures by pressurization, the fluid being chosen amongst those having, when in the gas state and liquid state, physical, chemical and/or electrical properties better than air and oil, respectively, for are quenching.
  • liquid insulants so far used in circuit breakers i.e., oils and similar products -have the advantage inherent in their liquid state, including a higher heat transfer coefficient than gases and therefore a greater rate of heat dissipation of the arc column, and therefore a short time constant which helps to break AC arcs as the voltage is passing through zero because of the rapidity with which the dielectric medium is restored.
  • a disadvantage of oil is that the arc decomposes it, conductive carbonaceous products being formed.
  • circuit breakers according to the invention combine the advantages of oil circuit breakers and gas circuit breakers but are free from the disadvantage of both kinds.
  • the new circuit breakers are of very similar construction to small-oil-volume circuit breakers, but the oil is replaced by a pressurized liquefied gas such as sulfur hexafluoride SF selenium hexafluoride, SeF C F and CF;, SP gases, electronegative gases, and perhalogenated hydrocarbons, such as CCl F known under the name of F reons, and so on.
  • a pressurized liquefied gas such as sulfur hexafluoride SF selenium hexafluoride, SeF C F and CF
  • SP gases electronegative gases
  • perhalogenated hydrocarbons such as CCl F known under the name of F reons, and so on.
  • the liquefiable dielectric gas is kept liquid at a substantially constant pressure which for some gases can be near or above the critical pressure of the gas.
  • the pressurizing means are such that the pressure variations produced by temperature variations are of limited amplitude.
  • circuit breakers of this kind one advantageous way of pressurizing the fluid sufficiently to maintain the same permanently liquid is to use a known hydraulic accumulator of the spring or compressed gas kind and with or without a separating piston.
  • the circuit breaker need not then be dependent upon an external source of power in normal operation. More particularly, no heating or cooling means are required for the circuit breaker to operate outside in all the extreme temperature conditions found, for instance, in continental France of from -40 to +60 C.
  • a circuit breaker according to the invention can comprise a hermetic rupture chamber in which at least one fixed contact and one moving contact are disposed and which is tilled with a liquefiable dielectric gas in the liquid state.
  • a circuit breaker according to the invention can also comprise a hydraulic accumulator whose liquid compartment is filled with the same gas in the liquid state and is hydraulically connected to the rupture chamber and experiences the pressure applied by the resilient means at the accumulator, such pressure being enough to keep the gas liquid in normal outside temperature conditions.
  • connecting means between the rupture chamber, the accumulator and/or the outside are provided to enable air to be bled from the system and taking into operation and to deal with volume variation caused by temperature variations.
  • FIG. 1 is a diagrammatic sectioned view of a circuit breaker according to the invention.
  • FIG. 2 shows a preferred embodiment of the invention
  • FIG. 3 is a separate view of a spring-biased hydraulic accumulator for pressuring the system
  • FIG. 4 is a diagrammatic sectioned view of a circuit breaker according to the invention.
  • FIGS. 57 each show a way of filling the circuit breaker with liquefiable gas
  • FIG. 8 shows a level-indicating system for a circuit breaker according to the invention.
  • FIG. 9 shows another embodiment of a circuit breaker according to the invention wherein the liquid dielectric is pressurized by a pocket of gas disposed at the top of the rupture chamber.
  • FIG. 1 shows by way of example a ground-mounted circuit breaker having a rupture chamber 2 at the top of an insulating column 4.
  • the circuit breaker resembles the small-oil-volume type circuit breakers.
  • a movable contact 6 can move in the chamber 2 and is borne on by rubbing contacts 8 connected to a part 10 of a line to be broken and which can engage in a fixed contact or tulip contact 12 connected to another part 14 of such line.
  • the moving contact 6 is operated for closing and tripping by a conventional mechanism 16 including for instance, a hydraulic jack to which the contact 6 is connected by an insulated rod 18.
  • the internal volume of the chamber 2 is closed hermetically; more particularly, a gland 20 is provided where the moving contact 6 passes through the chamber end 22.
  • An insulated tube 24 extends into the internal volume or space 19 of the chamber 2, goes through the column 4 and terminates at a liquid compartment 26 of a hydraulic accumulator 28 which is at earth potential.
  • the liquid compartment 26, which can be bounded by a free piston 30, is kept pressurized by the conventional resilient means of the accumulator, such as a pressurized gas cushion 32 trapped in the second compartment of the accumulator.
  • the resilient means can take the form of a spring 33, as shown in FIG. 3.
  • the internal volume or spaces of the chamber 2, tube 24 and compartment 26 are filled completely by a liquefiable dielectric gas, such as SF or Freon, which is kept liquid by the pressure applied by the gas cushion 32.
  • a liquefiable dielectric gas such as SF or Freon
  • the gas used for the cushion e. g. nitrogen
  • a conventional valve 34 is provided for reinflatingthe accumulator, and a pressure gauge 36 gives a check on the pressure of the dielectric fluid in the circuit breaker and helps to estimate the quantity of liquid contained in the compartment 26; the pressure gauge 36 can, if required, control safety or pressure-restoring operations automatically.
  • An escape valve 38 at the top of the rupture chamber 2 is used to bleed air from the system when the same is taken into 1 operation.
  • the column 4 In a ground-mounted circuit breaker of the kind just described, the usual practice is for the column 4 to be filled with insulating oil, as is normal practice with known circuit breakers. However, the gland 20 may be difficult to keep tight after a time because of erosions of the moving contact 6 by the arc at rupture. In another embodiment of the invention, therefore, which is shown in FIG. 2, the hermetic separation, provided by the gland 20 and the chamber end 22, between the rupture chamber 2 and the interior of the column 4 is omitted and all these spaces are filled with pressurized liquefied dielectric gas. Only one seal between a stationary element and a moving element then remains and it is provided by a gland 40 at the bottom of the column 4, the gland 40 cooperating with jack rod 42 which can be completely smooth and does not experience erosion.
  • an escape tube 44 is disposed at the top of the rupture chamber 2 and comprises a nonreturn valve 46 through which fluid can flow only in the direction indicated by the arrow 48.
  • the tube or duct 44 is insulated and forms a return to the liquid compartment 26 of the accumulator 28.
  • the duct 24 connecting the liquid compartment 26 to the interior of the column 4 and chamber 2 has a nonreturn valve 50 through which fluid can flow only from the accumulator towards the circuit breaker.
  • a draincock 52 which is disposed at the bottom of the duct 44 and which is therefore at earth potential and readily accessible, can connect the interior of the circuit breaker to atmosphere for air bleeding purposes at startup.
  • the accumulator 28' can be isolated by a stop cock 54 during this operation.
  • a simple nonreturn valve can be used, in which event there is no need to open the stop cock 54 at startup.
  • these two valve devices 52, 54 can be combined as a single three-way valve.
  • the duct 24' has fitted to it a pressure gauge 36 and a branch 56 which can be connected to a source of liquefiable dielectric fluid to fill or topup the system.
  • a safety valve 57 can be provided somewhere in the system. Since most liquefiable dielectric gases are much heavier than air, opening the drain cock 52 at the start of filling ensures removal of all the air in the system.
  • FIG. 2 Another variant shown in FIG. 2 is the accumulator 28 since the liquid compartment 26 and the gas compartment 32 are not separated from one another by moving pistons; instead, the resilient cushion 32 of compressed gas, for instance, nitrogen, acts directly on the liquified dielectric gas contained in the compartment 26.
  • the circuit just described which connects the interior of the circuit breaker to the accumulator and selectively to atmosphere and a dielectric fluid source, also provide a one-way flow of the fluid in closed circuit and automatic bleeding of foreign gases.
  • the accumulator is charged to a pressure P (or else, in the case shown in FlG. 3, the accumulator spring applies a pressure P to the piston) such that the liquefiable dielectric gas is kept liquid at normal ambient temperatures.
  • P a pressure
  • the liquefiable dielectric gas is sulfur hexafluoride
  • SF the accumulator can be pressurized to at least 35 kg/cm.2 in normal temperature conditions.
  • the pressure can be merely about from 15 to 20 kg/cmF.
  • the volume of liquefiable dielectric gas in the circuit breaker decreases and the nonreturn valve 46 stays closed, but the valve 50 opens and a corresponding volume of liquefiable dielectric gas is transferred from the liquid chamber 26 of the accumulator to the circuit breaker;
  • the volume of the gas compartment 32 increases correspondingly and the pressure decreases, but since the temperature has dropped the dielectric fluid remains in the liquid state.
  • accumulator volume is so adapted to the volume of the circuit breaker containing the liquefied dielectric that pressure variations caused by temperature variations always maintain the dielectric in the liquid state, at least in that part of the circuit breaker where the arcis produced.
  • circuit breakers may be advantageous, since their freezing temperatures are very low and their critical temperatures are considerably above all the outside temperatures met with in practice. For the rest, they have a relatively low liquefaction pressure and, depending upon the particular kind actually used, the system can operate at pressures of from 15 to 2'0 kg/cm
  • the circuit breaker shown in FIG. 4 is similar to the circuit breaker shown in FIG. 1 in that the interior 19 of the rupture chamber 2 is filled with a liquefied dielectric gas, such as SF and is separated, by the chamber end 22 and a gland 20, from the interior of the insulated column 4 which can be filled with insulating oil.
  • the circuit breaker also resembles the circuit breaker shown in FIG. 2 to the extent that it comprises a closed circuit for the flow of liquid dielectric between the accumulator 28 and the rupture chamber 2.
  • the closed circuit comprises a duct 44 which extends at the top into the rupture chamber 2 and which communicateswith a duct 44 connected to the accumulator 28, a filter'60 being provided between the ducts 44 and 44', stop cocks 62, 54 being provided one each on each side of the filter 60.
  • the closed circuit also comprises ducts 24, 24 connected to the bottom of the chamber 2 and to the accumulator 28, respectively.
  • a circuit breaker according to the invention is filled for the first time by fractionated distillation, for instance, by one of the procedures shown in FIGS. 5 and 6.
  • nitrogen is injected from a cylinder connected to the branch 56, to remove all the air from the system before filling begins. Nitrogen is relatively cheap and, even if it does stay in the circuit, will not cause disturbances, particularly if the accumulator 28 is of the kind not having a separating piston.
  • a cylinder 66 of liquefied SF can be connected to the. branch 56 (FIG. 5) with the interposition of a compressor 68. Delivery from the cylinder is in the gas phase, any impurities in the liquid SF not entering the system.
  • the drain cock 52 is closed (preferably, the drain cock 52 is placed very near the filling branch 56 to obtain a thorough purging, as shown in FIG. 4) and the compressor 68 presses the system to the required value.
  • the cylinder 66 of SP is just connected to the branch 56 via a line 70 comprising a safety valve 72, and the cylinder 66 is heated; for instance, in awaterbath 74.
  • filling is by distillation, the system therefore being filled with purified dielectric.
  • the system can be filled.
  • a free piston 78 divides the reservoir 76 into a first compartment 80-which is filled with liquid SP and which can be connected by a duct 82 to thefilling branch 56-and a second compartment 84 which can be connected to a source of pressurized liquid, such as oil.
  • the source can comprise, for instance, a pump which draws oil from a reservoir 88 and delivers the oil at pressure to the compartment 84. Should the pressure become excessiveand when the piston 78 has reached the end of its travel, the pressurized oil discharges through a safety valve90.
  • a cock 92 of the reservoir 76 is then closed and a cock 94 of a duct 96 is opened to allow the oil in the compartment 84 to return to the tank 88. This procedure is useful for topping up the system, using just a small capacity reservoir 76.
  • a circuit breaker according to the invention can have provision for visual indication of the amount of liquefied dielectric fluid present in the system, for liquid SF looks-like water and is fully visible in a conventional sight glass type of water gauge.
  • One such system is shown in FIG. 8, only an accumulator 28, of the kind shown in FIG 2, beingshown with the two fluid flow ducts 44, 24' connected to it.
  • the same system can be used for an accumulator to which only one pressurizing duct, such as the duct 24 in FIG. 1, is connected.
  • the accumulator contains a volume 26 of liquid SF and thereabove a cushion 32 of compressed gas, for instance, nitrogen, which pressurizes the liquid SF directly and not via a piston.
  • a sight glass 98 is connected to the accumulator 28, preferably via two isolating cocks 100, 102. A visual check is therefore provided on the quantity of liquid dielectric and the quantity of cushioning gas.
  • the accumulator can be recharged with nitrogen via the valve 34.
  • the rupture chamber 2 is filled with liquid SF depending upon whether or not a hermetic partition is provided between the chamber 2 and the insulated column 4, the same can be filled either with liquid SF or with insulating or some other dielectric, such as gaseous SF
  • the liquid SF is kept pressurized by a cushion 106 of pressurized gas, such as nitrogen; instead of being trapped in an accumulator as in the previous cases, the cushion 106 is immediately above the level 106 of the dielectric in a compartment 108 disposed above the: rupture chamber 2.
  • the compartment 108 has a sight glass 98and a safety valve 110.
  • thermometer 112 which, in cooperation with the sight glass 98, enable the actual quantity of nitrogen contained in the system to be known in all circumstances.
  • the gas cushion 104 it might appear simpler for the gas cushion 104 to be formed by gaseous SF above the liquid SF
  • the gas used for the. cushion 104 has a higher liquefaction pressure than SP and is more particularly nitrogen
  • the pressure above the level 106 such pressure being above the vapor tension of the SP forces the liquid dielectric to fill the gap left by the moving contact 6 as the. same separates from the fixed contact 12; the arc is therefore really quenchedin the liquid dielectric with an effect similar to blowing, since unionized dielectric is supplied" during the break action.
  • circuit breaker Only a single schematic kind of circuit breaker is shown in thedrawings, but the invention is of course of use with widely differing kinds of circuit breakers having single or multiple rupture chambers.
  • a circuit breaker comprising a circuit interrupting chamber containing a liquefied dielectric gas, a fixed contact member disposed in said chamber so as to lie within said liquefied gas, a movable contact member disposed in said chamber so as to be in the liquefied gas for all of its positions relative to the fixed contact member, and pressurizing means for continuously maintaining the liquefied gas under a pressure higher than the instantaneous vapor pressure of the liquefied dielectric gas, whereby all of said liquified gas is constantly maintained in its liquid state.
  • a circuit breaker as set forth in claim 1, wherein said pressurizing means comprises, above the circuit interrupting chamber containing the liquid dielectric, a compartment filled with a compressed gas, such as nitrogen, whose liquefaction pressure is appreciably greater than the liquefaction pressure of the liquefied dielectric gas at equal temperatures, the compressed gas forming a resilient cushion for pressurizing the liquefied dielectric gas contained in the circuit interrupting chamber.
  • a compressed gas such as nitrogen

Landscapes

  • Gas-Insulated Switchgears (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
  • Circuit Breakers (AREA)
US867959A 1965-01-21 1969-10-20 Circuit breaker having pressurized liquified gas continuously maintained above instantaneous vapor pressure Expired - Lifetime US3569651A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR92002722 1965-01-21
FR92044848 1966-01-05

Publications (1)

Publication Number Publication Date
US3569651A true US3569651A (en) 1971-03-09

Family

ID=26235605

Family Applications (1)

Application Number Title Priority Date Filing Date
US867959A Expired - Lifetime US3569651A (en) 1965-01-21 1969-10-20 Circuit breaker having pressurized liquified gas continuously maintained above instantaneous vapor pressure

Country Status (8)

Country Link
US (1) US3569651A (nl)
JP (1) JPS4840940B1 (nl)
BE (1) BE675378A (nl)
DE (1) DE1640124A1 (nl)
DK (1) DK123677B (nl)
GB (1) GB1104228A (nl)
NL (1) NL149941B (nl)
SE (1) SE331852B (nl)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3842227A (en) * 1971-09-30 1974-10-15 J Gratzmuller Circuit-breaker having dielectric liquid under pressure
US4273978A (en) * 1978-06-09 1981-06-16 Electric Power Research Institute, Inc. Liquid interrupter module
US5187339A (en) * 1990-06-26 1993-02-16 Merlin Gerin Gas insulated high-voltage circuit breaker with pneumatic operating mechanism
US20210242803A1 (en) * 2020-01-03 2021-08-05 C-Motive Technologies, Inc. Electrostatic motor
CN117558579A (zh) * 2024-01-11 2024-02-13 宁波天安智能电网科技股份有限公司 一种高压控弧开关及其工作方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5084939U (nl) * 1973-12-09 1975-07-19
JPS5478135U (nl) * 1977-11-14 1979-06-02
JPS5713382U (nl) * 1980-06-28 1982-01-23

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB609589A (en) * 1945-03-23 1948-10-04 Westinghouse Electric Int Co Improvements in or relating to fluid blast electric circuit interrupters
FR1281324A (fr) * 1960-11-28 1962-01-12 Perfectionnements aux disjoncteurs hydrauliques à grand pouvoir de coupure
DE1143890B (de) * 1958-12-02 1963-02-21 Licentia Gmbh OElarmer Leistungsschalter
FR1323669A (fr) * 1962-02-28 1963-04-12 Disjoncteur hydraulique à grand pouvoir de coupure
FR1349314A (fr) * 1962-12-03 1964-01-17 Perfectionnements apportés au circuit de purge des vérins hydrauliques pour disjoncteurs
DE1164536B (de) * 1958-12-09 1964-03-05 Licentia Gmbh Elektrische Schaltanlage mit Druckoelschaltern
US3150245A (en) * 1957-09-13 1964-09-22 Westinghouse Electric Corp Liquefied gas circuit interrupters

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB609589A (en) * 1945-03-23 1948-10-04 Westinghouse Electric Int Co Improvements in or relating to fluid blast electric circuit interrupters
US3150245A (en) * 1957-09-13 1964-09-22 Westinghouse Electric Corp Liquefied gas circuit interrupters
DE1143890B (de) * 1958-12-02 1963-02-21 Licentia Gmbh OElarmer Leistungsschalter
DE1164536B (de) * 1958-12-09 1964-03-05 Licentia Gmbh Elektrische Schaltanlage mit Druckoelschaltern
FR1281324A (fr) * 1960-11-28 1962-01-12 Perfectionnements aux disjoncteurs hydrauliques à grand pouvoir de coupure
FR1323669A (fr) * 1962-02-28 1963-04-12 Disjoncteur hydraulique à grand pouvoir de coupure
FR1349314A (fr) * 1962-12-03 1964-01-17 Perfectionnements apportés au circuit de purge des vérins hydrauliques pour disjoncteurs

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3842227A (en) * 1971-09-30 1974-10-15 J Gratzmuller Circuit-breaker having dielectric liquid under pressure
US4273978A (en) * 1978-06-09 1981-06-16 Electric Power Research Institute, Inc. Liquid interrupter module
US5187339A (en) * 1990-06-26 1993-02-16 Merlin Gerin Gas insulated high-voltage circuit breaker with pneumatic operating mechanism
US20210242803A1 (en) * 2020-01-03 2021-08-05 C-Motive Technologies, Inc. Electrostatic motor
US11811334B2 (en) 2020-01-03 2023-11-07 C-Motive Technologies, Inc. Electrostatic motor
US11870368B2 (en) 2020-01-03 2024-01-09 C-Motive Technologies, Inc. Electrostatic motor
CN117558579A (zh) * 2024-01-11 2024-02-13 宁波天安智能电网科技股份有限公司 一种高压控弧开关及其工作方法
CN117558579B (zh) * 2024-01-11 2024-03-22 宁波天安智能电网科技股份有限公司 一种高压控弧开关及其工作方法

Also Published As

Publication number Publication date
JPS4840940B1 (nl) 1973-12-04
DE1640124A1 (de) 1971-10-14
BE675378A (nl) 1966-05-16
DK123677B (da) 1972-07-17
GB1104228A (en) 1968-02-21
NL149941B (nl) 1976-06-15
SE331852B (nl) 1971-01-18
NL6600732A (nl) 1966-07-22

Similar Documents

Publication Publication Date Title
US2221720A (en) Electric circuit interrupter
US2981815A (en) Circuit interrupter
US3569651A (en) Circuit breaker having pressurized liquified gas continuously maintained above instantaneous vapor pressure
US4086461A (en) High-voltage circuit-interrupters
US3406269A (en) Fluid-blast circuit breakers having means for increasing the density of the fluid during interruption
US2387589A (en) Circuit breaker
US3947650A (en) Gas-insulated switch for an underground power distrubution system
CA1201956A (en) Fail-safe hydraulically operated circuit breaker accumulator arrangement
US3614355A (en) Sf{11 {0 system with constant density and constant pressure differential maintaining means for a high-voltage switchgear
US3045086A (en) Circuit interrupters
US3303310A (en) Dual-pressure circuit interrupter control device
US2020475A (en) Electric switch
US3564179A (en) Double exhaust valve for gas blast circuit-breakers including a check valve and underpressure responsive valve
EP0476906B1 (en) Switch mechanism
GB378493A (en) Improvements relating to electric switches or circuit breakers, fusible cut-outs andlightning arresters
SU735196A3 (ru) Электрический силовой выключатель
US3060294A (en) Circuit interrupter
US3137777A (en) Compressed-gas circuit interrupter with means for maintaining temperature of gas therein
CA1046621A (en) Compressed-gas multiphase circuit-breaker installation
US2162588A (en) Electric circuit breaker
US3379849A (en) Dual-pressure gas-blast circuit breaker with piston means and interrupting unit in closed tank
US3073931A (en) Compressed-gas circuit interrupter
US4264794A (en) Circuit interrupter including arc extinguishing fluid pressurization means and pressure accumulating means
US1945916A (en) Switch with contacts surrounded by a medium under pressure
US3210952A (en) Reclamation device for gas-type circuit interrupters