US3538382A - Triggered vacuum gap overvoltage protective device - Google Patents

Triggered vacuum gap overvoltage protective device Download PDF

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Publication number
US3538382A
US3538382A US699120A US3538382DA US3538382A US 3538382 A US3538382 A US 3538382A US 699120 A US699120 A US 699120A US 3538382D A US3538382D A US 3538382DA US 3538382 A US3538382 A US 3538382A
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Prior art keywords
voltage
gap
triggering
gaps
conductor
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US699120A
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English (en)
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Sidney R Smith Jr
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General Electric Co
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General Electric Co
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/06—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using spark-gap arresters

Definitions

  • a triggered vacuum gap device having a triggering circuit that includes among its desirable characteristics; a very low time lag, reliably stable operation, long maintenance free life, and the ability to operate with system power rather than requiring a secondary source of power.
  • the triggering circuit includes a secondary gap electrically connected in series with a voltage dropping resistor across a line voltage that is applied to the main high voltage vacuum gap of the device. The voltage dropping resistor is connected in parallel with the triggering gap of the device to cause it to spark over when the secondary gap breaks down and allows current to flow through the resistor thereby developing a sparkover voltage across the gap.
  • This invention relates to electrical discharge devices that operate by the ionization of vaporized, normally solid material in an evacuated space, and more particularly to a triggering circuit for initiating ionization within such devices.
  • One desirable way of injecting a plasma into a vacuum gap is to provide auxiliary gas-loaded triggering electrodes that evolve a plasma when energized.
  • a plasma evolving triggering arc may be initiated between hydrogen-loaded titanium electrodes that are separated by a few mils distance by applying a high voltage pulse across the electrode gap.
  • the triggering gaps themselves require a substantial voltage to initiate sparkover.
  • such triggering gaps have been sparked over by discharging a high voltage capacitor or other external source of high voltage energy into the gap. The problem with such a method is that the capacitors needed are both space consuming and expensive.
  • the triggering apparatus of my invention avoids the foregoing problems inherent in prior art devices and provides a very low time lag triggering function which is insensitive to the polarity of an initiating voltage surge. Moreover, my triggering apparatus requires no external source of energy or large component parts, such as high voltage capacitors, for initiating the triggering. Further important advantages inure to my triggering apparatus due to its mode of operation. Specifically, the operating circuitry of my apparatus handles only a limited current; therefore, the operating characteristics of its components remain stable because they are not subjected to appreciable arcing. Also, the arcing that does occur across these components is external from the main vacuum gap and it is of very short duration because it is cleared instantly when voltage is collapsed across the components by the initiation of an arc across the main gap.
  • an object of my invention is to provide a triggered vacuum gap device having a reliable triggering circuit with very low time lag.
  • a further object of my invention is to provide a triggering circuit for a vacuum gap device which is insensitive to the polarity of an initiating voltage surge.
  • Still another object of my invention is to provide a vacuum gap device having triggering means disposed outside of the device thereby to increase the stability of the operating characteristics of the triggering apparatus.
  • a further object of my invention is to provide a triggered vacuum gap device for an electrical system to assure low time lag and very stable voltage limiting protection for the system.
  • FIG. 1 is a schematic diagram of a circuit embodying one form of my invention illustrated in conjunction with a side elevation view, partly in cross section, of a vacuum gap device shown with respect to a high voltage transmission line conductor.
  • FIG. 2 is a preferred embodiment of the triggering apparatus of my invention shown with a schematic diagram of a circuit that is operatively connected to a vacuum gap device depicted in side elevation, partly in cross section, and connected in a circuit with a nonlinear resistor or other voltage surge limiting means to a high voltage power conducting system.
  • FIG. 1 there is shown, schematically, a portion of a high voltage transmission system conductor, or line 1, which is adapted to transmit electric power from a suitable high voltage source, such as a direct current generator 2, to some remote destination.
  • Voltage limiting means must be provided in order to protect such transmission systems from damage due to high voltage surges which may be caused either by natural forces, such as lightning, or by transient voltages created during switch ing operations.
  • a vacuum gap device 3 is connected by conductors 4 and 5 between the line 1 and ground. This vacuum gap device 3 is preferably constructed as shown and claimed in US. Pat. 3,087,092Latferty, assigned to the assignee of the present invention.
  • the envelope 6 comprises a sealed envelope 6 that is evacuated to a hard vacuum, i.e., to a pressure of 10-5 millimeters of mercury or lower.
  • the envelope 6 comprises a casing 7 formed of a suitable insulating material such as ceramic, and a pair of metallic end caps 8 and 9 joined in vacuum-tight relationship to the respective opposite ends of the insulating casing 7 by any suitable sealing means 10, such as brazing.
  • Electrodes 11 and 12 Disposed within the evacuated envelope 6 and electrically connected to end plates 8 and 9, respectively, are main electrodes 11 and 12. Electrodes 11 and 12 define a main vacuum gap 13 therebetween.
  • a bypass circuit is formed across main gap 13 from line conductor 1 through conductors 4 and 5 and terminals 11 and 12 to ground, when the gap 13 is rendered conductive by having an are formed across it. It will be understood that for given applications the length of gap 13 can be predetermined so that a single gap can be relied upon to withstand normal line-to-ground voltage without breaking down. Of course, higher voltage circuits could be protected with such (predetermined gap) devices by connecting an appropriate number of such gaps in series to form the bypass circuit, as is well known in the art.
  • the main gap 13 will be between three-eigl1ts and five-eighths of one inch in length. Therefore, in order to cause the gap 13 to break down when the voltage to ground on the line 1 reaches a predetermined magnitude at which system components would be in eminent danger of flashing over, or insulation failure, there is provided a triggering gap 14 located within the conical recess 12a of electrode 12.
  • the triggering gap 14 is formed by a cylindrical ceramic insulating support 15 which serves both as a bushing for conductor 16 to insulate it from the conductive end wall 9, and as a support for two thin layers of metal 17a and 17b bonded to its upper end with the gap 14 therebetween.
  • the conductor 16 terminates in a metal cap 18 which is hermetically sealed to the inner end of ceramic support 15 by any conventional ceramicto-metal sealing technique that assure a vacuum-tight seal.
  • the bonded metal layers 17a and 17b are formed of a metal, such as titanium, which is a good getter for active gases, such as hydrogen, and which is capable of absorbing a large quantity thereof.
  • the lines of field distribution at the interface between a metal and a ceramic body in intimate contact are highly favorable to a voltage breakdown at the interface. Accordingly, a relatively low voltage appearing across the triggering gap 14 can initiate a discharge from one of these interfaces across the trigger gap 14.
  • a series circuit is formed from conductor 16 through metal cap 18 and bonded metal layer 17a across the gap 14 the bonded metal layer 17b, which is in electrical contact with electrode 12, and thence through conductor 5 to ground. Therefore, in order to initiate a sparkover of triggering gap 14, it is only necessary to apply a voltage of predetermined suitable magnitude to .conductor 16.
  • the triggering circuit 19 which includes a voltage-responsive current conducting means 20 electrically connected in series with the current-responsive voltage distributing means 21 between the line 1 and ground.
  • the voltage distributing means 21 is depicted as a resistor 21a
  • the voltage-responsive current conducting means 20 comprises a plurality of pairs of secondary arc terminals 22 each defining an arc gap 22a therebetween.
  • a current limiting resistor 23 is connected in series with the arc gaps 22a and resistor 21a between the conductor -1 and ground to prevent an unduly large current from flowing through the series circuit 19 when it is conductive, thereby to assure the stable operation of the circuit.
  • a plurality of voltage grading resistors 24 are connected respectively in parallel across each of the gaps 22a and are all connected in series.
  • the gaps 22a are preionized by a preionizer 22b connected in parallel therewith, as taught in US. Pat. 3,223,874Carpenter, which is assigned to the assignee of the present invention.
  • the body of preionizer 22b may be formed of a ceramic composition, plastic or mica as disclosed in the referenced patent. It will be understood that any other suitable preionizing means may be employed to afford the desired degree of consistency of sparkover voltage level.
  • resistor 23 is connected in parallel with a capacitor 25 for the purpose of shaping the volt-time sparkover characteristic of the circuit 19. It will be understood that the numbers and size of gaps 22a can be varied to suit the demands of particular applications without departing from the scope of my invention.
  • secondary gaps 22a are normally nonconductive but are adapted to be conductive when at least a predetermined magnitude of voltage exists on the conductor 1.
  • This predetermined magnitude of voltage may vary with relation to the normal line voltage transmitted by conductor 1, from a value of two and one-half times normal line voltage in typical power transmission systems rated less than 345 kilovolts down to about 1.5 times normal line voltage for extra high voltage transmission systems ranging up to 1000 kilovolts.
  • a suitably high voltage is distributed across the voltage grading resistors 24 to cause the pre-ionized secondary gaps 22a: to sparkover and, thus, allow a current to fiow through resistor 21a to ground.
  • resistors 23 and 21a Since the value of resistors 23 and 21a have been preselected to allow an adequately large current to flow through resistor 21a under such voltage surge conditions to develop a voltage on conductor 16 that is sufficient to cause triggering gap 14 to sparkover, the gap 14 sparks over immediately.
  • the bonded metal plates 17 and 18 evolve hydrogen gas sorbed therein, which rapidly breaks down the main gap 13 between main terminals 11 and 12, so that the surge voltage on line 1 is shorted to ground through the above mentioned bypass circuit including conductors 4 and 5 and the vacuum gap device 3.
  • FIG. 2 of the drawing there is shown a preferred embodiment of my invention illustrated with respect to a high voltage transmission line conductor 1' that carries power from an alternating current source 2' to some remote point.
  • a vacuum gap device 3 is electrically connected by conductors 4' and 5 in series with a nonlinear valve resistor 26 between line conductor 1' and ground.
  • the non-linear resistor 26 is illustrated diagrammatically simply as a labeled box, but it will be understood by those skilled in the art that a plurality of non.
  • linear resistors may be connected in series to form a lightning arrester or other suitable arc discharge means adapted to be connected in series with the arc discharge device 3'.
  • the vacuum gap device 3 comprises a cylindrical ceramic side wall 7' sealed in vacuum-tight relation to metallic end walls 8 and 9 that in turn are electrically connected to the main gap terminals 11 and 12' which define main gap 13 therebetween.
  • the trigger gaps 1-4 and 27 associated respectively with main electrodes 12 and 11' are identical in structure and function with the triggering gap 14 discussed above with reference to FIG. 1. Therefore, the arrangement and structure of these components and their associated elements will not be described again here.
  • Conductor 16' electrically connects the gap 14' to the series connected voltage-responsive current conducting means 20' and current-responsive voltage distributing means 21, and conductor 28 electrically connects the triggering gap 27 to voltage distributing means 21b.
  • the current responsive voltage distributing means 21 is formed by impedances 21a. and 21b which may be suitable resistors or any other voltage-dropping means that will develop a suitable voltage across triggering gaps 14a and 27 to cause them to sparkover when the current conducting means 20' are conductive.
  • the current conducting means 20' comprises series connected resistors 29 and 30, a plurality of series connected pairs of secondary electrodes 22' each of Which defines secondary gaps 22a therebetween and each of which is preferably preionized with a shunt-connected block of insulating material 22b so that the gaps 22a will break down at a consistent voltage level.
  • a plurality of voltage grading resistors 24' are each connected respectively in parallel across the secondary gaps 22a and all connected in series with one another.
  • triggering circuit 19' is completed by connecting a conductor 31 between one end of resistor 21a and conductor to thereby connect the voltage distributing resistor 21a in parallel with the triggering gap 14'.
  • a bypass circuit around triggering circuit 19' is provided from line conductor 1' through conductors 4' and 5 and the vacuum gap device 3" and valve resistor 26 to ground.
  • a major advantage of this preferred embodiment of my invention is that the main arc inducing triggering gap sparkover is initiated precisely at a predetermined volttime value regardless of the polarity of the voltage surge initiating the sparkover at either gap 14' or 27.
  • the invention can be equally as Well utilized to protect transformers, circuit breakers and other component parts of high voltage systems by affording means for quickly and reliably grounding high voltage surges at a precise volt-time value regardless of the polarity of the over-voltage surge.
  • the invention may be utilized to improve the performance and reliability of protective gap devices incorporated in direct current systems where over-voltage surges of opposite polarity do not exist.
  • An electric discharge device comprising an evacuated enveloye having mounted therein main arc-gap electrodes and a trigger electrode adjacent to one of said main electrodes but spaced therefrom to form a trigger gap, current-responsive voltage distributing means and voltage-responsive current conducting means electrically connected in series across said main electrides to form a bypass circuit around the main electrodes, said current conducting means being adapted to be normally nonconductive and to be conductive only when at least a predetermined magnitude of voltage exists across said main electrodes, thereby to cause said current-responsive voltage distributing means to be actuated only when said current conducting means is conductive, and circuit means adapted to apply a voltage developed by said voltage distributing means across said triggering gap to cause the gap to sparkover when the voltage distributing means is actuated.
  • said voltage-responsive current conducting means comprises at least one pair of spaced-apart secondary electrodes that define a secondary gap therebetween, said secondary gap being electrically connected in series with said current-responsive voltage distributing means.
  • An electric charge device as defined in claim 2 including a substance adapted to pre-ionize said secondary gap disposed adjacent thereto.
  • An electric discharge device as defined in claim 2 including means to form a Vacuum for said secondary gap, said secondary gap being disposed in said vacuum.
  • said current-responsive voltage distributing means comprises an electrical impedance of predetermined magnitude
  • said circuit means comprises conductors arranged to electrically connect said impedance in parallel with said triggering gap.
  • said voltage-responsive current conducting means comprises a plurality of series connected pairs of spacedapart secondary electrodes each of which defines a secondary gap therebetween.
  • An electric discharge device as defined in claim 10 including a plurality of voltage grading resistors each electrically connected in parallel with one of said secondary gaps and all connected in a series circuit across said main electrodes.
  • An electric discharge device comprising a highly evacuated envelope having mounted therein main arc gap electrodes and trigger electrodes disposed respectively adjacent to said main electrodes but spaced therefrom to form triggering gaps, current-responsive voltage distributing means and voltage-responsive current conducting means electrically connected in series across said mam arc gap electrodes, said current conducting means being adapted to be norm-ally nonconductive and to be conductive only when at least a predetermined magnitude of voltage exists across said main electrodes thereby to 7 cause said current-responsive voltage distributing means to be actuated only when said current conducting means is conductive, and circuit means adapted to apply a voltage developed across said voltage distributing means to at least one of said triggering gaps to cause it to sparkover when the voltage distributing means is energized.
  • An electric discharge device as defined in claim 12 wherein said current-responsive voltage distributing means comprises a plurality of resistors each respectively electrically connected by said circuit means in parallel with one of said triggering gaps.
  • said voltage-responsive current conducting means comprises at least one pair of secondary electrodes arranged to define a secondary gap therebetween, and electrically connected in series with said resistors.
  • said current-responsive voltage distributing means comprises an electrical impedance electrically connected in parallel with each of said triggering gaps whereby a voltage drop developed across said impedance will simultaneously be developed across said triggering gaps.
  • An electric discharge device as defined in claim 16 including a plurality of voltage-grading resistors each respectively connected in parallel with one of said secondary gaps and all electrically connected in series.
  • a triggered vacuum gap device comprising:
  • An electrical system as defined in claim 18 including at least one nonlinear resistorelectrically connected in series with said triggered vacuum device between said conductor and ground.
  • a triggered vacuum gap device comprising:
  • a triggering circuit for a spark gap triggered vacuum gap comprising current-responsive voltage distributing means and voltage-responsive current conductin means adapted to be electrically connected in series across said vacuum gap, said current conducting means being adapted to be normally non-conductive and to be conductive only when at least a predetermined magnitude of voltage exists across the extremities of said series circuit,.circuit means for electrically connecting said voltage distributing means in parallel with said spark gap, said voltage distributing means being operative to cause said spark gap to sparkover when connected thereto through said circuit means and actuated by current passed through, said conducting means in response to said predetermined magnitude of voltage occurring across the extremities of said series circuit.

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US699120A 1968-01-19 1968-01-19 Triggered vacuum gap overvoltage protective device Expired - Lifetime US3538382A (en)

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CH (1) CH487525A (de)
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3649874A (en) * 1969-09-02 1972-03-14 Siemens Ag Overvoltage arrester
US4167370A (en) * 1976-11-01 1979-09-11 Massachusetts Institute Of Technology Method of an apparatus for self-sustaining high vacuum in a high voltage environment
US4328523A (en) * 1979-12-28 1982-05-04 Home Oil Company Limited Method and apparatus for the protection of electrical equipment from high voltage transients
EP0061838A1 (de) * 1981-03-02 1982-10-06 The M-O Valve Company Limited Überspannungsschutzvorrichtungen
US4419711A (en) * 1979-12-28 1983-12-06 Seguin Herb J J Method and apparatus for the protection of electrical equipment from high voltage transients
US5854732A (en) * 1997-03-10 1998-12-29 Argus Photonics Group, Inc. High voltage arcing switch initiated by a disruption of the electric field
US6618234B1 (en) 2000-09-08 2003-09-09 The Toro Company Lightning protection for irrigation controls
US20100118453A1 (en) * 2007-04-16 2010-05-13 Siemens Aktiengesellschaft Apparatus for Protection of Converter Modules
EP2720240A1 (de) * 2012-10-11 2014-04-16 ABB Technology AG Stabförmiges Teil einer Schaltvorrichtungsanordnung mit mittlerer Spannung mit einer Auslösungslückeneinheit
CN115116791A (zh) * 2021-03-19 2022-09-27 西安翰德电力电器制造有限公司 一种真空断路器及真空断路保护系统

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004006988B4 (de) * 2003-11-28 2014-02-06 Dehn + Söhne Gmbh + Co. Kg Überspannungsschutzeinrichtung auf Funkenstreckenbasis, umfassend mindestens zwei in einem druckdichten Gehäuse befindliche Hauptelektroden
DE102011102937B4 (de) * 2010-08-17 2017-03-02 DEHN + SÖHNE GmbH + Co. KG. Anordnung zur Zündung von Funkenstrecken

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2878428A (en) * 1953-08-31 1959-03-17 Asea Ab Over-voltage protection device
US3223874A (en) * 1963-12-13 1965-12-14 Gen Electric Preionizer for use in overvoltage protective devices
US3339112A (en) * 1965-01-28 1967-08-29 Gen Electric Voltage limiting protective arrangement for high voltage power circuits
US3413524A (en) * 1964-07-14 1968-11-26 English Electric Co Ltd Apparatus for providing a protective spark gap for a d.c. powerline

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2878428A (en) * 1953-08-31 1959-03-17 Asea Ab Over-voltage protection device
US3223874A (en) * 1963-12-13 1965-12-14 Gen Electric Preionizer for use in overvoltage protective devices
US3413524A (en) * 1964-07-14 1968-11-26 English Electric Co Ltd Apparatus for providing a protective spark gap for a d.c. powerline
US3339112A (en) * 1965-01-28 1967-08-29 Gen Electric Voltage limiting protective arrangement for high voltage power circuits

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3649874A (en) * 1969-09-02 1972-03-14 Siemens Ag Overvoltage arrester
US4167370A (en) * 1976-11-01 1979-09-11 Massachusetts Institute Of Technology Method of an apparatus for self-sustaining high vacuum in a high voltage environment
US4328523A (en) * 1979-12-28 1982-05-04 Home Oil Company Limited Method and apparatus for the protection of electrical equipment from high voltage transients
US4419711A (en) * 1979-12-28 1983-12-06 Seguin Herb J J Method and apparatus for the protection of electrical equipment from high voltage transients
EP0061838A1 (de) * 1981-03-02 1982-10-06 The M-O Valve Company Limited Überspannungsschutzvorrichtungen
US4628398A (en) * 1981-03-02 1986-12-09 The M-O Valve Company Limited Surge voltage protection arrangements
US5854732A (en) * 1997-03-10 1998-12-29 Argus Photonics Group, Inc. High voltage arcing switch initiated by a disruption of the electric field
US6618234B1 (en) 2000-09-08 2003-09-09 The Toro Company Lightning protection for irrigation controls
US20100118453A1 (en) * 2007-04-16 2010-05-13 Siemens Aktiengesellschaft Apparatus for Protection of Converter Modules
US8390968B2 (en) * 2007-04-16 2013-03-05 Siemens Aktiengesellschaft Apparatus for protection of converter modules
EP2720240A1 (de) * 2012-10-11 2014-04-16 ABB Technology AG Stabförmiges Teil einer Schaltvorrichtungsanordnung mit mittlerer Spannung mit einer Auslösungslückeneinheit
WO2014056598A1 (en) * 2012-10-11 2014-04-17 Abb Technology Ag A pole part of a medium voltage circuit breaker arrangement comprising a triggered gap unit
CN115116791A (zh) * 2021-03-19 2022-09-27 西安翰德电力电器制造有限公司 一种真空断路器及真空断路保护系统

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DE1902214A1 (de) 1969-09-04
FR2000441A1 (de) 1969-09-05
CH487525A (de) 1970-03-15

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