(19)
(11)EP 2 747 232 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
27.07.2022 Bulletin 2022/30

(21)Application number: 12199030.3

(22)Date of filing:  21.12.2012
(51)International Patent Classification (IPC): 
H02H 9/06(2006.01)
H01T 15/00(2006.01)
H02H 7/16(2006.01)
H01T 4/20(2006.01)
H01T 2/02(2006.01)
(52)Cooperative Patent Classification (CPC):
H01T 4/20; H02H 7/16; H02H 9/06; H01T 2/02; H01T 15/00

(54)

Method and arrangement for triggering a series spark gap

Verfahren und Anordnung zum Auslösen einer seriellen Funkenlücke

Procédé et dispositif de déclenchement d'un éclateur à air en série


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
25.06.2014 Bulletin 2014/26

(73)Proprietor: General Electric Technology GmbH
5400 Baden (CH)

(72)Inventor:
  • Jussi, Pöyhönen
    33330 Tampere (FI)

(74)Representative: Openshaw & Co. 
8 Castle Street
Farnham, Surrey GU9 7HR
Farnham, Surrey GU9 7HR (GB)


(56)References cited: : 
DE-B- 1 056 716
US-A- 4 029 997
US-A- 3 348 100
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF THE INVENTION



    [0001] The invention relates to a method for triggering a series spark gap.

    [0002] The invention further relates to an arrangement for triggering a series spark gap.

    BACKGROUND OF THE INVENTION



    [0003] In connection with high voltage lines, for instance, there are employed series capacitor banks to compensate for line inductance. In parallel with a capacitor bank, in protection thereof, there is generally coupled a metal oxide varistor and/or a spark gap. Solutions for triggering a spark gap are disclosed in publications SE 8205236, Fl 88012, US4029997, US3348100, DE1056716 and WO 2007/003706, for example.

    BRIEF DESCRIPTION OF THE INVENTION



    [0004] The object of the present invention is to provide a new solution for triggering a series spark gap.

    [0005] The invention is characterized by the features of the independent claims.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0006] In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached drawings, in which

    [0007] Figure 1 shows schematically a solution for protecting a series capacitor bank.

    DETAILED DESCRIPTION OF THE INVENTION



    [0008] Figure 1 is a single line diagram of a solution for protecting a series capacitor bank. The series capacitor bank 1 is shown in Figure 1 only schematically. Series capacitors are used to compensate for the inductance of a transmission line 2. Series capacitors will increase a transmission capacity and stability of the line 2. Series capacitors are also used to share the load between parallel lines.

    [0009] The series capacitor bank 1 may be protected by a spark gap 3, for example. Further, a metal oxide varistor (MOV) 4 may be used for protecting the series capacitor bank 1. The series capacitor bank 1 may be a thyristor controlled series capacitor bank. However, for the sake of clarity such thyristor control means are not shown in Figure 1.

    [0010] Figure 1 further shows switches K1, K2 and K3, which switches are used for bypassing the series capacitor bank 1, if needed.

    [0011] The spark gap 3 comprises a first enclosure 5a and a second enclosure 5b. The first enclosure 5a may also be called a lower enclosure and the second enclosure 5b may also be called an upper enclosure.

    [0012] The first enclosure 5a comprises main electrodes 6a and 6b. Correspondingly, the second enclosure 5b comprises main electrodes 6c and 6d. In connection with the main electrode 6b there is an auxiliary electrode 7a which is in the same potential as the main electrode 6b. Correspondingly there is a second auxiliary electrode 7b in connection with the main electrode 6d. The second auxiliary electrode 7b is in the same potential as the main electrode 6d.

    [0013] The first enclosure 5a further comprises a middle electrode 8a. Correspondingly the second enclosure 5b comprises a middle electrode 8b. Thus the spark gap 3 is a series spark gap comprising four partial spark gaps. The first partial spark gap is between the main electrode 6a and the middle electrode 8a. The second partial spark gap is between the middle electrode 8a and the auxiliary electrode 7a. The third partial spark gap is between the main electrode 6c and the middle electrode 8b. The fourth partial spark gap is between the middle electrode 8b and the second auxiliary electrode 7b.

    [0014] Figure 1 further shows a main bushing 9a in connection with the first enclosure 5a and, correspondingly, a main bushing 9b in connection with the second enclosure 5b. Figure 1 further shows a middle bushing 10a in connection with the first enclosure and a middle bushing 10b in connection with the second enclosure 5b.

    [0015] The arrangement shown in Figure 1 further comprises voltage divider capacitors 11a, 11b, 11c and 11d. The voltage divider capacitors 11a to 11d divide the supply voltage Ucap acting over the partial spark gaps in steady state conditions or, in other words, during continuous operation mode. The supply voltage Ucap is the voltage across the series capacitor bank 1. The arrangement further comprises auxiliary spark gaps 12a, 12b and 12c. The auxiliary spark gaps may be gas pressure spark gaps, i.e. trigatrons, for example. The first auxiliary spark gap 12a may be a trigatron that is force-triggered with a triggering pulse for igniting the first trigatron 12a. The arrangement may be provided with an ignition coil 13 for forming a triggering pulse for the second trigatron 12b. The third auxiliary spark gap 12c may be called an auxiliary trigatron.

    [0016] In series with the first auxiliary spark gap there is a first current-limiting damping resistor 14a. In series with the second auxiliary spark gap 12b there is a second current-limiting damping resistor 14b and in series with the third auxiliary spark gap 12c there is a third current-limiting damping resistor 14c.

    [0017] The series resistors 14a, 14b and 14c are of different sizes. In one embodiment the resistance of the first resistor 14a is lower than the resistance of the second resistor 14b and the resistance of the second resistor 14b is lower than the resistance of the third resistor 14c. In another embodiment the resistance of the second resistor 14b is 2 to 3 times higher than the resistance of the first resistor 14a and the resistance of the third resistor 14c is 2 to 3 times higher than the combined resistance of the resistors 14b and 14a. In a third embodiment the resistance of the first resistor 14a is 2 kΩ, the resistance of the second resistor 14b is 5 kΩ and the resistance of the third resistor 14c is 17,5 kΩ. The resistance of the resistors 14a to 14c may vary between 100Ω and 100kΩ, for example. The resistance of the resistor must be high enough to limit the current through the trigatron. On the other hand, the resistance of the resistor must not be too high to ensure sufficiently fast discharge of the capacitors 11a to 11c.

    [0018] In steady state conditions voltage is divided equally between all partial spark gaps. Thus the voltage division is symmetric in steady state conditions because the voltage is divided symmetrically by the voltage divider capacitors 11a to 11d. During the triggering of the spark gap, an asymmetric voltage division is used. Thus symmetric and asymmetric voltage division is combined.

    [0019] In the beginning of an ignition process, before triggering, the voltage over the partial spark gaps is divided symmetrically such that the voltage across each partial spark gap is ¼ * Ucap if the capacitors 11a to 11d are substantially equal in size. Dimensioning the capacitors to be equal in size may provide cost efficiency. The voltage division is determined by the high impedance of the voltage divider capacitors 11a to 11d. The capacitance of the capacitors 11a to 11d may vary between 100 pF and 100000 pF, for example. In another embodiment the capacitance of the capacitors 11a to 11d may vary between 2000 pF and 40000 pF, for example. In the present embodiment the capacitance of the capacitors 11a to 11d may be 3000 pF, for example. The capacitances of the capacitors 11a to 11d must be high enough to prevent line current, which is to pass through the series capacitor bank 1, from passing through the capacitors 11a to 11d. Furthermore the reactances of the capacitors 11a to 11d must be substantially higher than the reactances of the series resistors 14a to 14c.

    [0020] Next, the first auxiliary spark gap 12a is force-triggered. Thus the first auxiliary spark gap 12a is ignited by a control system command. The second auxiliary spark gap 12b is ignited by a voltage increase and ignition coil 13 current caused by the ignition of the first auxiliary spark gap 12a. The voltage Ucap acts then over the second enclosure 5b and therefore the third auxiliary spark gap 12c ignites. Because the auxiliary spark gaps 12a, 12b and 12c are ignited, the voltage divider capacitors 11a, 11b and 11c are discharged.

    [0021] Thereafter the whole voltage Ucap acts across the fourth partial spark gap between middle electrode 8b and the auxiliary electrode 7b which therefore ignites the partial spark gap.

    [0022] At this stage the current path runs through the fourth partial spark gap and the auxiliary spark gaps 12a, 12b and 12c. At this stage the series resistors 14a, 14b and 14c determine the voltage division between the auxiliary spark gaps 12a, 12b and 12c.

    [0023] In an embodiment the voltage division ratio of the series resistors 14a, 14b and 14c is 2.5 between the resistors. This is achieved, for example, such that the resistance of the first resistor is 2 kΩ, the resistance of the second resistor is 5 kΩ and the resistance of the third resistor 14c is 17.5 kΩ. At that stage the voltage across the third partial spark gap that is between the main electrode 6c and the middle electrode 8b rises to 0.71 Ucap, which ignites the air gap.

    [0024] The current path runs through the second enclosure 5b and the first auxiliary spark gap 12a and the second auxiliary spark gap 12b. The voltage across the second partial spark gap between the first auxiliary electrode 7a and the first middle electrode 8a rises to 0.71 Ucap thus igniting the partial spark gap.

    [0025] Thereafter the whole voltage Ucap acts across the first partial spark gap between the first middle electrode 8a and the first main electrode 6a which ignites the partial spark gap. Thus the whole spark gap 3 is ignited and the series capacitor bank 1 is bypassed.

    [0026] A voltage across a single partial spark gap before forced triggering is thus 0.25 Ucap. During the ignition process the voltage rises to 0.71 to 1 Ucap for a single partial spark gap. Thus the voltage rush across a single partial spark gap is 2.84 -4 pu (per unit).

    [0027] It is also possible to dimension the components such that the voltage rush across each partial spark gap during triggering is substantially equal in size. In one embodiment the components are dimensioned such that the voltage rush across one partial spark gap differs less than 10% from the voltage rush across other partial spark gaps.

    [0028] In one embodiment the voltage rush across each partial spark gap is dimensioned to be substantially equal such that the capacitances of the capacitors 11a and 11d are smaller than the capacitances of the capacitors 11b and 11c. In this embodiment the resistances of the resistors 14a to 14c may correspond to the resistances in the previous embodiment. The capacitances of the capacitors 11a and 11d may be 2143pF and the capacitances of the capacitors 11b and 11c may be 3000pF, for example.

    [0029] In a continuous operation mode the supply voltage Ucap is divided between the partial spark gaps such that voltage across the fourth partial spark gap between the middle electrode 8b and the auxiliary electrode 7b is 0,29 Ucap. The voltage across the third partial spark gap between the main electrode 6c and the middle electrode 8b is 0,21Ucap. The voltage across the second partial spark gap between the first auxiliary electrode 7a and the first middle electrode 8a is 0,21Ucap. The voltage across the first partial spark gap between the first middle electrode 8a and the first main electrode 6a is 0,29 Ucap.

    [0030] When the third, second and first partial spark gaps are bypassed, the whole voltage Ucap acts across the fourth partial spark gap which provides a voltage rush of 3,4 pu across the fourth partial spark gap.

    [0031] When the fourth partial spark gap has been ignited the voltage across the third partial spark gap rises to 0,71Ucap, which provides a voltage rush of 3,4 pu across the third partial spark gap, thus igniting the third partial spark gap.

    [0032] Thereafter the voltage across the second partial spark gap rises to 0,71 Ucap, providing a voltage rush of 3,4 pu across the second partial spark gap, thus igniting the second partial spark gap.

    [0033] Thereafter the whole voltage Ucap acts across the first partial spark gap, providing a voltage rush of 3,4 pu across the first partial spark gap, thus igniting the first partial spark gap.

    [0034] Thus, when the components are dimensioned such that the voltage rush across each partial spark gap is substantially equal, the minimum voltage rush across a single partial spark gap may be rather high, which improves the ignition of the spark gap. The values of the components disclosed above are only examples and it is thus possible to dimension the components case by case to fulfill the required needs.

    [0035] The described solutions provide improvement in forced triggering performance also in extreme conditions. The forced triggering voltage of the spark gap can be lowered which enables to mitigate line circuit breaker transient recovery voltage. The described spark gap arrangement can be used in extreme climatic conditions because the arrangement is reliably ignited in cold conditions and self-firing of the spark gap can be avoided also in hot conditions. Lowering the forced triggering voltage also enables a high self-ignition voltage level, whereby a self-ignition in high pollution and during snow storms, for example, may be avoided. The above-described arrangement further provides a fast ignition and allows greater manufacturing tolerances.

    [0036] It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

    [0037] The series spark gap comprises at least three partial spark gaps. In the embodiment shown in Figure 1 the series spark gap comprises four partial spark gaps. The series sparks gap may also comprise more than four partial spark gaps.

    [0038] Instead of or in addition to capacitors, the first voltage dividing means for dividing the supply voltage acting over the partial spark gaps during continuous operation mode may also be coils, resistors or metal oxide varistors, for example.

    [0039] Instead of or in addition to a trigatron, the bypass means arranged to bypass the partial spark gaps may also comprise other force-triggered airgaps or semiconductor components, for example.

    [0040] In addition to the series resistors, the second voltage dividing means comprised in the bypass means may also comprise metal oxide varistors or other non-linear or linear reactances or resistances, for example.


    Claims

    1. A method for triggering a series spark gap (3) in which there are at least three partial spark gaps in series, comprising

    in steady state conditions, dividing a supply voltage (Ucap) acting over the series of partial spark gaps symmetrically between the partial spark gaps by first voltage dividing means (11a-11d),

    during triggering, bypassing more than half of the partial spark gaps using bypass means such that more than half of the supply voltage (Ucap) acts over the partial spark gaps that are not bypassed, whereby the partial spark gap or the partial spark gaps that are not bypassed ignite,

    characterised by

    during triggering, dividing the voltage acting over the bypassed partial spark gaps asymmetrically between the bypassed partial spark gaps using the bypass means comprising auxiliary spark gaps (12a-12c) and resistors (14a-14c) of different sizes in series with a corresponding auxiliary spark gap bypassing a corresponding partial spark gap, whereby the bypassed partial spark gaps ignite sequentially in the order determined by the asymmetric voltage division.


     
    2. The method of claim 1, wherein in steady state conditions the supply voltage acting over the partial spark gaps is divided by capacitors.
     
    3. The method of claim 1 or 2, wherein at least one of the bypass means comprises a trigatron.
     
    4. An arrangement for triggering a series spark gap (3), which series spark gap comprises at least three partial spark gaps in series, which arrangement comprises first voltage dividing means (11a-11d) for dividing, in steady state conditions, a supply voltage (Ucap) acting over the series of partial spark gaps symmetrically between the partial spark gaps, and bypass means arranged to bypass, during triggering, more than half of the partial spark gaps such that more than half of the supply voltage (Ucap) acts over the partial spark gaps that are not bypassed, whereby the partial spark gap or the partial spark gaps that are not bypassed ignite, the bypass means being arranged in parallel to said more than half of the partial spark gaps, characterised in that the bypass means comprise second voltage dividing means comprising auxiliary spark gaps (12a-12c) and resistors (14a-14c) of different sizes in series with a corresponding auxiliary spark gap, bypassing a corresponding partial spark gap, for providing, during triggering, an asymmetric voltage division of the voltage acting over the bypassed partial spark gaps between the bypassed partial spark gaps.
     
    5. The arrangement of claim 4, wherein the first voltage dividing means are capacitors.
     
    6. The arrangement of claim 4 or 5, wherein at least one of the bypass means comprises a trigatron.
     
    7. The arrangement of any one of claims 4 to 6, wherein the first voltage dividing means are substantially equal in size.
     


    Ansprüche

    1. Verfahren zum Auslösen einer seriellen Funkenstrecke (3), in welcher es zumindest drei Teilfunkenstrecken in Serie gibt, umfassend

    in Dauerzuständen, Aufteilen einer Versorgungsspannung (Ucap), welche über die Serie von Teilfunkenstrecken wirkt, symmetrisch zwischen den Teilfunkenstrecken durch erste Spannungsaufteilungsmittel (11a-11d),

    während Auslösen, Überbrücken mehr als der Hälfte der Teilfunkenstrecken unter Verwendung von Überbrückungsmitteln, sodass mehr als die Hälfte der Versorgungsspannung (Ucap) über die Teilfunkenstrecken wirkt, welche nicht überbrückt sind, wobei die Teilfunkenstrecke oder die Teilfunkenstrecken, welche nicht überbrückt sind, sich entzünden,

    gekennzeichnet durch

    während Auslösen, Aufteilen der über die überbrückten Teilfunkenstrecken wirkenden Spannung asymmetrisch zwischen den überbrückten Teilfunkenstrecken unter Verwendung der Überbrückungsmittel, umfassend Hilfsfunkenstrecken (12a-12c) und Widerstände (14a-14c) in unterschiedlichen Größen in Serie mit einer entsprechenden Hilfsfunkenstrecke, welche eine entsprechende Teilfunkenstrecke überbrückt, wobei die überbrückten Teilfunkenstrecken sich nacheinander in der Reihenfolge entzünden, welche durch die asymmetrische Spannungsaufteilung bestimmt wird.


     
    2. Verfahren nach Anspruch 1, wobei in Dauerzuständen die Versorgungsspannung, welche über die Teilfunkenstrecken wirkt, durch Kondensatoren aufgeteilt wird.
     
    3. Verfahren nach Anspruch 1 oder 2, wobei zumindest eines der Überbrückungsmittel ein Trigatron umfasst.
     
    4. Anordnung zum Auslösen einer seriellen Funkenstrecke (3), wobei die serielle Funkenstrecke zumindest drei Teilfunkenstrecken in Serie umfasst, wobei die Anordnung erste Spannungsaufteilungsmittel (11a-11d) zum Aufteilen, in Dauerzuständen, einer Versorgungsspannung (Ucap), welche über die Serie von Teilfunkenstrecken wirkt, symmetrisch zwischen den Teilfunkenstrecken, und Überbrückungsmittel, welche angeordnet sind, während Auslösen, mehr als der Hälfte der Teilfunkenstrecken zu überbrücken, sodass mehr als die Hälfte der Versorgungsspannung (Ucap) über die Teilfunkenstrecken wirkt, welche nicht überbrückt sind, umfasst, wobei die Teilfunkenstrecke oder die Teilfunkenstrecken, welche nicht überbrückt sind, sich entzünden, wobei die Überbrückungsmittel parallel zu der mehr als der Hälfte der Teilfunkenstrecken angeordnet sind, dadurch gekennzeichnet, dass die Überbrückungsmittel zweite Spannungsaufteilungsmittel umfassen, welche Hilfsfunkenstrecken (12a-12c) und Widerstände (14a-14c) in unterschiedlichen Größen in Serie mit einer entsprechenden Hilfsfunkenstrecke umfassen, welche eine entsprechende Teilfunkenstrecke überbrücken, um während Auslösen eine asymmetrische Spannungsaufteilung der über die überbrückten Teilfunkenstrecken wirkenden Spannung zwischen den überbrückten Teilfunkenstrecken bereitzustellen.
     
    5. Anordnung nach Anspruch 4, wobei die ersten Spannungsaufteilungsmittel Kondensatoren sind.
     
    6. Anordnung nach Anspruch 4 oder 5, wobei zumindest eines der Überbrückungsmittel ein Trigatron umfasst.
     
    7. Anordnung nach einem der Ansprüche 4 bis 6, wobei die ersten Spannungsaufteilungsmittel im Wesentlichen von gleicher Größe sind.
     


    Revendications

    1. Procédé de déclenchement d'un éclateur à air en série (3) dans lequel il y a au moins trois éclateurs à air partiels en série, comprenant

    dans des conditions uniformes de fonctionnement, la division d'une tension d'alimentation (Ucap) présentant une incidence sur les séries d'éclateurs à air partiels symétriquement entre les éclateurs à air partiels par des premiers moyens de division de tension (11a-11d),

    pendant le déclenchement, le court-circuitage de plus de la moitié des éclateurs à air partiels à l'aide de moyens de court-circuitage, de sorte que plus de la moitié de la tension d'alimentation (Ucap) présente une incidence sur les éclateurs à air partiels qui ne sont pas court-circuités, selon lequel l'éclateur à air partiel ou les éclateurs à air partiels qui ne sont pas court-circuités s'enflamment,

    caractérisé par

    pendant le déclenchement, la division de la tension présentant une incidence sur les éclateurs à air partiels court-circuités asymétriquement entre les éclateurs à air partiels court-circuités à l'aide des moyens de court-circuitage comprenant des éclateurs à air auxiliaires (12a-12c) et des résistances (14a-14c) de différentes tailles en série avec un éclateur à air auxiliaire correspondant court-circuitant un éclateur à air partiel correspondant, selon lequel les éclateurs à air partiels court-circuités s'enflamment séquentiellement dans l'ordre déterminé par la division de tension asymétrique.


     
    2. Procédé selon la revendication 1, dans lequel dans des conditions uniformes de fonctionnement, la tension d'alimentation présentant une incidence sur les éclateurs à air partiels est divisée par des condensateurs.
     
    3. Procédé selon la revendication 1 ou 2, dans lequel au moins un des moyens de court-circuitage comprend un trigatron.
     
    4. Agencement pour déclencher un éclateur à air en série (3), lequel éclateur à air en série comprend au moins trois éclateurs à air partiels en série, lequel agencement comprend des premiers moyens de division de tension (11a-11d) pour diviser, dans des conditions uniformes de fonctionnement, une tension d'alimentation (Ucap) présentant une incidence sur la série d'éclateurs à air partiels symétriquement entre les éclateurs à air partiels, et des moyens de court-circuitage agencés pour court-circuiter, pendant le déclenchement, plus de la moitié des éclateurs à air partiels de sorte que plus de la moitié de la tension d'alimentation (Ucap) présente une incidence sur les éclateurs à air partiels qui ne sont pas court-circuités, selon lequel l'éclateur à air partiel ou les éclateurs à air partiels qui ne sont pas court-circuités s'enflamment, les moyens de court-circuitage étant agencés en parallèle de ladite plus de la moitié des éclateurs à air partiels, caractérisé en ce que les moyens de court-circuitage comprennent des seconds moyens de division de tension comprenant des éclateurs à air auxiliaires (12a-12c) et des résistances (14a-14c) de différentes tailles en série avec un éclateur à air auxiliaire correspondant, court-circuitant un éclateur à air partiel correspondant, pour fournir, pendant le déclenchement, une division de tension asymétrique de la tension présentant une incidence sur les éclateurs à air partiels court-circuités entre les éclateurs à air partiel court-circuités.
     
    5. Agencement selon la revendication 4, dans lequel les premiers moyens de division de tension sont des condensateurs.
     
    6. Agencement selon la revendication 4 ou 5, dans lequel au moins un des moyens de court-circuitage comprend un trigatron.
     
    7. Agencement selon l'une quelconque des revendications 4 à 6, dans lequel les premiers moyens de division de tension sont sensiblement égaux en taille.
     




    Drawing








    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description