US3544847A - Flip-flop lightning arrester with reduced protective level - Google Patents

Flip-flop lightning arrester with reduced protective level Download PDF

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Publication number
US3544847A
US3544847A US762225A US3544847DA US3544847A US 3544847 A US3544847 A US 3544847A US 762225 A US762225 A US 762225A US 3544847D A US3544847D A US 3544847DA US 3544847 A US3544847 A US 3544847A
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United States
Prior art keywords
voltage
column
arrester
gaps
gap
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Expired - Lifetime
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US762225A
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English (en)
Inventor
Eugene C Sakshaug
James S Kresge
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General Electric Co
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General Electric Co
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Publication date
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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T4/00—Overvoltage arresters using spark gaps
    • H01T4/16—Overvoltage arresters using spark gaps having a plurality of gaps arranged in series
    • 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

  • This invention relates generally to voltage surge diverters and more particularly to improvements in valve type lightning arresters having parallel columns of current limiting spark gaps with a so-called flip-flop mode of operation.
  • a valve type lightning arrester comprises at least one valve resistor in series with at least one spark gap.
  • a valve resistor is a nonlinear resistor having a drooping voltage characteristic with increases in current caused by an instantaneous negative resistance-current characteristic.
  • a current limiting gap is a gap which after sparkover builds a counter voltage or voltage drop comparable to its sparkover voltage in a time which is long compared to the duration of an ordinary lightning surge but short in comparison to the time of an ordinary switching surge. Such gaps are well known in the art and are particularly useful in connection with direct current circuits as they are capable of clearing or sealing off against a non-cyclic ciro cuit voltage.
  • a recent form of valve type lightning arrester with current limiting gaps is the so-called flip-flop arrester in which there are two or more current limiting gaps or columns of gaps electrically, if not physically, in parallel.
  • one column will ordinarily spark over before the other one when a voltage surge strikes the arrester.
  • the sparked over gap or gaps will then build voltage until they spark over the gaps in the other column which immediately clears the arc in the first sparked over column.
  • the gaps in the second column then build voltage and continue the cycle by again sparking over the gaps in the first column. In this manner, a long duration switching surge can be discharged with intermittent operation of the gaps so that they do not overheat and lose their voltage building ability.
  • the voltage appearing across the valve resistors of the second column may exceed the voltage of the gaps of the first column immediately prior to sparkover.
  • the gaps of the first column will not clear, and the two columns may operate in parallel. In such a condition, without the cooling permitted by intermittent operation, the gaps will fail. Even if such simultaneous operation of both columns does not cause the gaps to fail, it is undesirable to allow the two columns to operate in parallel for any significant length of time because, since both columns are conducting, the sparkover of one does not prevent the other from building excessive voltage in which case the total arrester voltage may exceed the prescribed protective level.
  • the arrester sparkover is closely related to the system operating voltage or the voltage against which the arrester must be able to clear or seal off. Therefore, the sparkover level is more or less determined by operating voltage. Since the arrester protective 'level is greater than the sparkover voltage, the quality of protection that can be afforded to a system operating at a given voltage is limited.
  • the above described problem has been solved by obtaining an accurate measure of total arrester voltage by measuring an accurate sample or fraction of the arrester voltage and causing that fraction to spark over the non-conducting gap column in response to the voltage appearing across the arrester during the flow of current.
  • the voltage across the arrester during flow of current may be limited to arrester sparkover voltage thus providing protective levels for direct current arresters equivalent to those obtainable from A-C arresters operating on A-C systems.
  • An object of the invention is to provide a new and improved voltage surge diverter.
  • Another object of the invention is to provide an improved flip-flop lightning arrester with reduced protective level.
  • FIG. 1 is a schematic circuit diagram of an embodiment of the invention.
  • FIG. 2 is a modification thereof in which trigger gaps are used in the flip-flop columns.
  • the arrester 1 comprises parallel flip-flop legs or columns 4 and 4 in series with a common leg or valve resistance column 5.
  • Column 4 comprises current limiting gaps G
  • Impedances labeled Z Z are a sparkover control and grading circuit for controlling the voltage distribution between the series connected circuit elements of the column 4.
  • a relatively small number of valve resistors VR -VR are included in the gap column 4.
  • Gap column 4 is a duplicate of gap column 4 and the corresponding elements are similarly identified except that their letters are primed.
  • the common leg comprises valve resistor discs VR VR Resistors R and R which may be conventional or linear resistors and which have low resistance compared to the resistance of the grading network are connected between columns at such points that the number of gaps and valve elements between the R and R connections are some fixed percentage of the total number of gaps and valve elements in a current path through the complete arrester. For instance, if the arrester is made up of 100 gaps in each column and the number of valve elements in one column plus the valve elements outside the columns is also 100, gaps and 20 valve elements might be included between the R and R connections. However, as shown in FIG. 1, gaps G and G and valve resistors VR and VR of column 4 are included between the R and R auxiliary interconnections and the corresponding two gaps and two valve resistors of column 4 are included between those auxiliary interconnections.
  • the percentage of gaps between R and R is selected so that when those gaps spark over, the voltage appearing across the remaining gaps in the column is sufiicient to cause them to spark over.
  • spark over the gaps of column 4 are able to clear even at high current because the voltage appearing across the valve elements in column 4 is small compared to the voltage across all of the gaps in column 4'.
  • FIG. 2 illustrates how the principle of this invention may be applied to a low voltage arrester in which to achieve a low protective level the gaps in each column consist of but one set of triggered gaps.
  • the flip-flop arrester 1 has flip-fl0p columns 7 and 8 and a common valve resistor column 10.
  • Column 7 comprises main current limiting gap assemblies or units A and B and a trigger gap G, coupled to the main gaps A and B by an RC coupling circuit 9.
  • Column 8 is a duplicate of column 7 in which the corresponding parts are identified by the same letters and reference numerals primed.
  • the auxiliary resistive paralleling interconnection is indicated by the resistor R extending between the RC coupling circuits 9 and 9.
  • the trigger gap G which may be preionized if desired, has an accurate sparkover calibration somewhat lower than that of the gaps A and B.
  • B is momentarily eflectively short circuited through the capacitor of the RC circuit 9 thus impressing all the voltage on gap A which then sparks over thus raising the voltage of gap B to its sparkover voltage and when it sparks over it effectively short circuits and clears the trigger gap G.
  • the same operation is, of course, also true of the like elements in column 8.
  • the relation of VR and VR to VR must be the same as the relation of the voltage build capability of main gaps B to A. That is, if the resistivity of VR and VR were equal then gaps A and B must also have equal characteristics.
  • the coupling resistor R which is of low resistance compared to that of grading circuits (not shown in FIG. 2), assures that the trigger gap G or G in a nonconducting column senses and controls the sparkover in response to the voltage across the whole arrester.
  • a flip-flop lightning arrester having a plurality of discharge columns comprising respectively at least one current limiting gap electrically connected in series with at least one valve resistor, means for preventing the arrester discharge voltage from exceeding the arrester sparkover voltage, said means comprising a pair of resistors electrically connected in parallel between said columns at respectively spaced-apart points on the columns thereby to place a fixed percentage of the total series impedance of each of said columns between the connection points of said pair of resistors, whereby a discharge current through one of the columns develops a voltage across said fixed percentage of the total series impedance of the other column that is a fixed percentage of the total voltage across said one of said columns.
  • a flip-flop lightning arrester having common valve resistance in series with parallel columns each comprising a like number of current limiting gaps in series with a like amount of valve resistance, a resistive conductor interconnecting an intermediate point in each column, said 6 points being so selected that said conductor eifectively 6.
  • An arrester as defined in claim 3 in which the num- References C'ted ber of gaps in said fraction is such that when they spark UNITED STATES PATENTS over all the gaps in the same column spark over. 2,763,313 9/ 195 Beck 317 61 5.
  • An arrester as defined in claim 4 in which the amount of valve resistance in each fraction is such that J D MILLER, Primary Examiner when its column is conducting current, the gaps in said ULYSSES WELDON Assistant Examiner fraction of the other column will be sparked over at a 10 total arrester voltage equal to the arrester sparkover volt- U S C1, X R

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  • Emergency Protection Circuit Devices (AREA)
  • Thermistors And Varistors (AREA)
US762225A 1968-09-16 1968-09-16 Flip-flop lightning arrester with reduced protective level Expired - Lifetime US3544847A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US76222568A 1968-09-16 1968-09-16

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US3544847A true US3544847A (en) 1970-12-01

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US762225A Expired - Lifetime US3544847A (en) 1968-09-16 1968-09-16 Flip-flop lightning arrester with reduced protective level

Country Status (5)

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US (1) US3544847A (de)
JP (1) JPS4810974B1 (de)
CH (1) CH510946A (de)
GB (1) GB1286855A (de)
SE (1) SE369990B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657594A (en) * 1968-08-28 1972-04-18 Bbc Brown Boveri & Cie Lightning arrester
US4760486A (en) * 1985-08-28 1988-07-26 Licentia Patent-Verwaltungs-Gmbh Protection device against flashover in a transmitter circuit
US20150288176A1 (en) * 2012-11-16 2015-10-08 Phoenix Contact Gmbh & Co.Kg Ignition circuit

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2763818A (en) * 1954-10-14 1956-09-18 Westinghouse Electric Corp Lighting arrester

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2763818A (en) * 1954-10-14 1956-09-18 Westinghouse Electric Corp Lighting arrester

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3657594A (en) * 1968-08-28 1972-04-18 Bbc Brown Boveri & Cie Lightning arrester
US4760486A (en) * 1985-08-28 1988-07-26 Licentia Patent-Verwaltungs-Gmbh Protection device against flashover in a transmitter circuit
US20150288176A1 (en) * 2012-11-16 2015-10-08 Phoenix Contact Gmbh & Co.Kg Ignition circuit
US9906016B2 (en) * 2012-11-16 2018-02-27 Phoenix Contact Gmbh & Co. Kg Ignition circuit

Also Published As

Publication number Publication date
GB1286855A (en) 1972-08-23
JPS4810974B1 (de) 1973-04-09
DE1944816B2 (de) 1973-02-01
CH510946A (de) 1971-07-31
DE1944816A1 (de) 1970-03-26
SE369990B (de) 1974-09-23

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