DE102013225835B4 - series spark gap - Google Patents

Abstract

Series spark gap with at least one first spark gap (FS1) with a first main electrode (FSA1) and a second main electrode (FSA2) and a second spark gap (FS2) with a first main electrode (FSA3) and a second main electrode (FSA4), the second main electrode ( FSA2) of the first spark gap (FS1) is connected in series with the first main electrode (FSA3) of the second spark gap (FS2), each of the spark gaps (FS1, FS2) having an auxiliary ignition electrode (H1, H2), the auxiliary ignition electrodes (H1 , H2) are connected to one another via a switching circuit (ZK), the first main electrode (FSA1) of the first spark gap (FS1) and the second main electrode (FSA4) of the second spark gap (FS2) serving as connections (A1, A2) for the series spark gap to Are available, with the auxiliary ignition electrode (H1) of the first spark gap (FS1) and the auxiliary ignition electrode (H2) of the second spark gap (FS2) electrically connected to one another via a circuit (ZK). he are connected, the switching circuit (ZK) being electrically insulated from the second main electrode (FSA2) of the first spark gap (FS1) and the first main electrode (FSA3) of the second spark gap (FS2), and the auxiliary ignition electrodes (H1, H2) connecting circuit (ZK) has a gas discharge tube (GDT1).

Description

The invention relates to a series spark gap.

Background of the Invention

In numerous applications of electrical equipment, impulses, especially high-energy impulses such as those occurring with lightning, represent a serious hazard.

Overvoltage protection devices are being used in increasing numbers to counteract these dangers. Dissipation by means of spark gaps has proven particularly useful for high-energy impulses. Although varistors can also be used in principle, it has been shown that spark gaps provide a better reduction in the residual voltage after the spark gaps have been triggered to a desirable low level compared to a varistor-based solution.

As soon as a spark gap has ignited, a conductive connection is established across the arc gap and the impulse is discharged here. Various mechanisms are available for ignition. For example, a breakdown between the electrodes of a spark gap can be brought about by the targeted use of a high-voltage pulse. However, the provision of such a targeted high-voltage pulse is only possible with complex wiring.

A cheaper alternative is possible by means of auxiliary electrodes, such as those in EP 1 566 868 B1 is disclosed to the applicant. An example spark gap FS ₁ is in 1 shown. A resistive conductive connection is used between one of the main electrodes FSA ₂ of a spark gap and an auxiliary electrode H ₁ . However, this resistive conductive connection only has a comparatively low current-carrying capacity. If the current exceeds the current-carrying capacity, an arc plasma is created and as a result of the resulting ionization, the main ignition gap between the main electrodes FSA ₁ and FSA ₂ becomes conductive more quickly.

A follow current quenching capability corresponding to the power to be switched must be provided, particularly in high-power (DC and AC) networks.

In order to provide this follow current extinguishing capability in systems with high nominal voltages, ie voltages above 230 or above 400 V, series circuits are usually used for cost reasons. The voltage across the series connection of spark gaps is thus divided between two or more spark gaps. In 2 an exemplary arrangement of spark gaps FS ₁ and FS ₂ is shown. Both spark gaps have their own ignition circuit, which is formed here by means of a gas-filled surge arrester GDT ₁ and a varistor VAR ₁ in the case of the spark gap FS ₁ , and which is also formed here by means of a gas-filled surge arrester GDT ₂ and a varistor VAR in the case of the spark gap FS _{2 2} is formed.

In the known variants of series connection of spark gaps, due to the independent ignition circuits, it cannot be ensured that both spark gaps will ignite at the same time. For example, this is in 3 using the example of the series connection 2 shown. There, the voltage at the series spark gap caused by the exemplary pulse initially rises sharply and after a few µs one spark gap is ignited (after about 5 µs), whereupon the voltage, which initially also rises sharply, shows a first dip. However, the tension is still very high. Only after about another 5 µs does the other spark gap ignite and thus the current drop more sharply. 3 thus clearly shows that the spark gaps become conductive with a time lag. The voltage curve gradually falls to the level of the relevant spark gap burning voltage. The residual voltage level is very high due to the ignition circuits connected in series.

I.e. by igniting the spark gaps in series, the residual voltage remains at a high level for longer, which is undesirable. In addition, with a delayed ignition of a further ignition circuit, this becomes longer and is therefore more heavily loaded. Thus, the ignition circuit must be designed for a higher load in order to provide a time-delayed ignition, which in turn leads to higher costs. If the ignition circuit is not designed for a higher load, there is a risk.

From the US patent U.S.A. 4,860,156 another arrangement from the field of overvoltage protection is known. This arrangement for a series capacitor bank, which is arranged in a high-voltage line L, has two individual spark gaps to protect the series capacitor bank. In the circuit shown there, a complex circuit is required to trigger the spark gaps.

Furthermore, from the pre-registered but subsequently published German patent application DE 10 2012 022 399 A1 an ignition circuit is known in which the ignition circuit contains varistors, which, however, can have leakage currents due to aging.

The invention is based on the object of providing an improved arrangement which, on the one hand, is cost-effective and, on the other hand, allows the residual voltage to be reduced quickly and reliably.

The object is achieved according to the invention by the features of the independent claim. Advantageous refinements of the invention are specified in the dependent claims.

The invention is explained in more detail below with reference to the attached drawing based on preferred embodiments.

• 1 eine schematische Darstellung einer Funkenstrecke mit Hilfselektrode aus dem Stand der Technik zum Einsatz in Ausführungsformen der Erfindung,
• 2 eine schematische Darstellung einer Reihenschaltung von zwei Funkenstrecken mit Hilfselektrode gemäß Stand der Technik
• 3 ein Diagramm, das den Zusammenhang von Strom und Spannung bei der Reihenschaltung aus 2 aufzeigt,
• 4 eine schematische Darstellung einer Reihenschaltung von zwei Funkenstrecken mit Hilfselektrode gemäß Ausführungsformen der Erfindung, und
• 5 ein Diagramm, das den Zusammenhang von Strom und Spannung bei der Reihenschaltung aus 4 aufzeigt.

Show it

• 1 a schematic representation of a spark gap with an auxiliary electrode from the prior art for use in embodiments of the invention,
• 2 a schematic representation of a series connection of two spark gaps with auxiliary electrode according to the prior art
• 3 a diagram showing the relationship between current and voltage in a series connection 2 shows
• 4 a schematic representation of a series connection of two spark gaps with an auxiliary electrode according to embodiments of the invention, and
• 5 a diagram showing the relationship between current and voltage in a series connection 4 shows.

4 shows a schematic representation of a series connection of two spark gaps with an auxiliary electrode according to embodiments of the invention.

The series spark gap has at least one first spark gap FS ₁ with a first main electrode FSA ₁ and a second main electrode FSA ₂ . Furthermore, the series spark gap has at least one second spark gap FS ₂ , likewise with a first main electrode FSA ₃ and a second main electrode FSA ₄ . Further spark gaps can also be provided in the series circuit without further ado.

The second main electrode FSA ₂ of the first spark gap FS ₁ is connected in series with the first main electrode FSA ₃ of the second spark gap FS ₂ .

Each of the spark gaps FS ₁ , FS ₂ has at least one auxiliary ignition electrode H ₁ , H ₂ . The auxiliary ignition electrodes H ₁ , H ₂ are connected to one another via a circuit ZK, with the first main electrode FSA ₁ of the first spark gap FS ₁ and the second main electrode FSA ₄ of the second spark gap FS ₂ being available as terminals A ₁ , A ₂ for the series spark gap .

This means that the spark gaps FS ₁ , FS ₂ connected in series are provided with a common ignition circuit circuit ZK. The arrangement ensures that the spark gaps switch at the same time.

For example, this is in 5 using the example of the series connection 4 shown. There, the voltage caused by the exemplary pulse across the series spark gap initially rises less than in the 3 and after a few µs the two spark gaps ignite (approx. after 5 µs), whereupon the voltage shows a dip. Already after this dip, the voltage has dropped to about the same level as in the example of the 3 only after 10 µs. 5 thus clearly shows that the spark gaps essentially become conductive at the same time. The voltage curve drops immediately to the level of the respective spark gap burning voltage. The residual voltage level can also be lower than in the series circuit 3 lie with the same spark gaps. However, this depends on the dimensioning of the components of the ignition circuit wiring ZK.

This means that an improved arrangement is made available by means of the series connection presented, which on the one hand is cost-effective and on the other hand provides a quick and safe reduction in the residual voltage.

In an advantageous embodiment, spark gaps with auxiliary electrodes, as in EP 1 566 868 B1 disclosed by the applicant, used, ie the auxiliary ignition electrodes H ₁ , H ₂ are arranged in an electrically conductive connection on the first main electrode FSA ₁ of the first spark gap FS ₁ or in an electrically conductive connection on the second main electrode FSA ₄ of the second spark gap FS ₂ . A resistive conductive connection is used between the main electrode FSA ₁ of a first spark gap and a first auxiliary electrode H ₁ or between the main electrode FSA ₄ of a second spark gap and a second auxiliary electrode H ₂ . However, these resistive (resistive) conductive connections have only one comparative low current carrying capacity. If the current exceeds the current-carrying capacity, an arc plasma is created and as a result of the resulting ionization, the main ignition gap between the main electrodes FSA ₁ and FSA ₂ or FSA ₃ and FSA ₄ becomes conductive more quickly.

Of course, other spark gaps with other auxiliary electrodes can also be used as an alternative.

In one embodiment of the invention, the circuit ZK has a gas discharge tube GDT ₁ . This means that the advantageous switching behavior of gas discharge tubes can be used sensibly for the ignition circuit here as well. The gas arrester GDT ₁ provides the insulation in the normal state. In an advantageous embodiment, the ignition voltage of the gas arrester GDT ₁ lies below the ignition voltage of the spark gaps, ie the gas arrester GDT ₁ sensibly ignites before the main spark gap.

In yet another embodiment of the invention, the circuit ZK has a varistor VAR ₁ . This means that the advantageous switching behavior of varistors for the ignition circuit can also be used in a sensible manner here.

Of course, the circuit ZK can also have other components, but it has been shown that the switching behavior is particularly favorable if the circuit ZK has both a varistor VAR ₁ and a gas discharge tube GDT ₁ .

In the event of a discharge event, the gas discharge tube GDT ₁ in the ZK circuit ignites first. The current that is established flows via both auxiliary electrodes H ₁ and H ₂ . Only when the ionization of both spark gaps FS ₁ and FS ₂ is essentially complete does the current commutate to spark gaps FSA ₁ and FSA ₂ or FSA ₃ and FSA ₄ as the main discharge path. The load (current integral) of the circuit ZK corresponds to that of a single spark gap of the same type, ie only a lower load has to be taken into account since delayed ignition does not occur.

In the circuit variant presented, the two spark gaps FS ₁ and FS ₂ are connected via an "insulated" electrode. Ie the connection of the two spark gaps between FSA ₂ and FSA ₃ is potential free. This ensures joint ignition.

In other words, in the event of a discharge event, the gas discharge tube GDT ₁ in the ZK circuit ignites first. The current that is established flows via both auxiliary electrodes H ₁ and H ₂ . Only when the ionization of both spark gaps FS ₁ and FS ₂ is essentially complete does the current commutate to spark gaps FSA ₁ and FSA ₂ or FSA ₃ and FSA ₄ as the main discharge path.

In a particularly inexpensive variant, the individual spark gaps FS ₁ and FS ₂ used for the series spark gap are essentially identical in construction.

By means of the presented invention, it is thus possible to achieve an ignition delay time that is less than or equal to the ignition delay time of an individual spark gap. The residual voltage is greatly minimized at an early stage, i.e. more than with a normal series connection of spark gaps.

Without further ado, the series connection can also be carried out in a common housing G, as in 4 shown, only be provided with the necessary connections A ₁ and A ₂ .

Reference List

FS1, FS2

spark gap

FSA1, FSA2, FSA3, FSA4

main electrode

H1, H2

auxiliary ignition electrode

CC

circuit

A1, A2

connections

GDT1, GDT2

gas arrestor

VAR1, VAR2

varistor

G

Housing

Claims (4)

Series spark gap with at least one first spark gap (FS ₁ ) with a first main electrode (FSA ₁ ) and a second main electrode (FSA ₂ ) and a second spark gap (FS ₂ ) with a first main electrode (FSA ₃ ) and a second main electrode (FSA ₄ ) , wherein the second main electrode (FSA ₂ ) of the first spark gap (FS ₁ ) is connected in series with the first main electrode (FSA ₃ ) of the second spark gap (FS ₂ ), each of the spark gaps (FS ₁ , FS ₂ ) having an auxiliary ignition electrode (H ₁ , H ₂ ), the auxiliary ignition electrodes (H ₁ , H ₂ ) being connected to one another via a circuit (ZK), the first main electrode (FSA ₁ ) of the first spark gap (FS ₁ ) and the second main electrode (FSA ₄ ) of the second spark gap (FS ₂ ) as connections (A ₁ , A ₂ ) for the series spark gap, the auxiliary ignition electrode (H ₁ ) of the first spark gap (FS ₁ ) and the auxiliary ignition electrode (H ₂ ) of the second spark gap ( FS ₂ ) are electrically connected to one another via a circuit (ZK), the circuit (ZK) being electrically insulated from the second main electrode (FSA ₂ ), the first spark gap (FS ₁ ) and the first main electrode (FSA ₃ ) of the second spark gap (FS ₂ ), and wherein the auxiliary ignition electrodes (H ₁ , H ₂ ) connecting circuit (ZK) has a gas discharge tube (GDT ₁ ). series spark gap claim 1 , characterized in that the auxiliary ignition electrodes (H ₁ , H ₂ ) are electrically conductively connected to the first main electrode (FSA ₁ ) of the first spark gap (FS ₁ ) or electrically conductively connected to the second main electrode (FSA ₄ ) of the second spark gap (FS ₂ ) is arranged. Series spark gap according to one of the preceding claims, characterized in that the switching circuit (ZK) has a varistor (VAR ₁ ). Series spark gap according to one of the preceding claims, characterized in that the first spark gap (FS ₁ ) and the second spark gap (FS ₂ ) are essentially identical in construction.

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