DE102014215282B3 - Combined surge protection device with integrated spark gap - Google Patents

Abstract

The invention relates to a combined overvoltage protection device with an integrated spark gap (8) and with a fuse connected in series (F), wherein the series circuit to a supply network with a first potential (L) and a different second potential (N) is connectable wherein the spark gap comprises two main electrodes (FS1, FS2), comprising a housing having a first terminal (A1) and a second terminal (A2), wherein the first terminal (A1) is electrically conductively connected to the fuse (F), and wherein the second terminal (A2) is electrically conductively connected to the first main electrode (FS1) of the spark gap (8), the second main electrode (FS2) of the spark gap (8) being electrically connected to the fuse (F) inside the housing, wherein the fuse (F) comprises a fuse wire (5) connecting the first terminal (A1) to the second main electrode (FS2), wherein d The fuse (F) furthermore has a further contact (3), wherein the further contact (3) is insulated from the first connection (A1) and insulated from the second main electrode (FS2) and in a non-triggered state without contact with the fusible conductor (5 ), wherein the combined overvoltage protection device further comprises a plasma channel (13) which leads from the combustion chamber of the spark gap (8) in the vicinity of the fusible conductor (5), that plasma can act on the hot melt targeted degrading.

Description

The invention relates to a combined overvoltage protection device with an integrated spark gap.

A variety of electrical equipment as well as electrical wiring is protected in the event of faults by fuses. This can cause errors of various kinds. The most common errors can be understood as overload errors or short-circuit faults.

Typically, a fuse can then be triggered. In this case, the current flowing through the fuse heats so much that at least partial, if not complete, melting of the fusible conductor occurs. This melting is usually associated with the occurrence of an arc whereby material of the fusible conductor evaporates. This steam settles elsewhere, with the arc cooling to the extent that the current is limited and eventually shut off.

The melting of the fusible conductor is determined by its material and geometry properties, so that depending on the material and / or geometry of the fusible conductor, a respective amount of heat Q for evaporation of the fusible conductor is necessary. Typically, the reflow characteristics and associated rated tripping currents are described as the melt integral I ² t.

However, it should be noted that this current, which represents a fault, still flows through the device to be protected or the system to be protected.

In particular, in the case of high short-circuit currents there is thus the danger of damage which is actually to be avoided, since the power limit of the device to be protected is exceeded.

In addition, it should be noted that not only in the phase of melting the fusible conductor, a current flows, but also in the phase of extinguishing.

Ie. only the integration of the two current flow regions over time leads to the passage integral.

Thus, in dimensioning, this passage integral must actually be taken into account in order to avoid damage.

However, this is often neglected incorrectly, so it comes to misdimensioning.

Special requirements apply in the event that the device to be protected is an overvoltage protection device, because they should allow high currents to pass without causing the fuse at the same time but also at low residual currents, as z. B. may occur in case of damage to the surge protection device or as Netzfolgestrom switch off early. While the former requirement often leads to high rated current values of the fuse, the second requirement can be sensibly realized only with low nominal current values.

At the same time, there is an ever increasing trend towards small installation spaces. With previous fuses, however, the requirements are incompatible.

From the DE 20 2013 002 222 U1 is an overvoltage protection device with short-circuit function for low-voltage systems for insertion into a NH fuse-base known. From the EP 0860 918 A1 is a Überspannungsableiteinrichtung with outflow known. From the DE 10 2011 053 415 A1 The applicant is a thermal separation device for surge protective devices known.

The invention is therefore based on the object to provide a space-saving and efficient and cost-effective combination of surge protection and safety devices.

The object is achieved according to the invention by the features of the independent claim. Advantageous embodiments of the invention are specified in the subclaims.

The invention will be explained in more detail with reference to the accompanying drawings with reference to preferred embodiments.

Show it

1 a first embodiment of a combined overvoltage protection device according to the invention, and

2 a use of the first embodiment of a combined overvoltage protection device according to the invention with an exemplary overvoltage protection device, and

3 a detail relating to embodiments of the invention

The 1 and 2 show a combined surge protection device with an integrated spark gap 8th and with a fuse F connected in series therewith.

As shown, the series connection can be connected to a supply network having a first potential L and a second potential N different therefrom.

The spark gap has at least two main electrodes FS1, FS2.

The combined overvoltage protection device has a housing with a first terminal A ₁ and a second terminal A ₂ . The first terminal A ₁ is electrically connected to the fuse F, and the second terminal A ₂ is electrically conductive with the first main electrode FS _{1 of} the spark gap 8th connected. The second main electrode FS _{2 of} the spark gap 8th is electrically connected to the fuse F inside the housing, the fuse F a fuse element 5 which connects the first terminal A ₁ to the second main electrode FS ₂ .

The fuse F also has another contact 3 on, with further contact 3 isolated to the first contact 1 and isolated to the second main electrode FS ₂ .

In operation and in a non-triggered state is the further contact 3 contactless to the fusible conductor 5 ,

The first contact 1 is directly connected to the first potential L during operation.

In operation is the spark gap 8th directly connected to the second potential N. The further contact 3 is also directly connected to the second potential N during operation.

The combined overvoltage protection device also has a plasma channel 13 up, out of the combustion chamber of the spark gap 8th in the neighborhood of the fusible link 5 leads, so that plasma can act on the enamel wire targeted degrading.

In a first solution according to 1 , is the beginning of the plasma channel 13 within the spark gap 8th , At an overload of the spark gap 8th , Plasma and ionized gas can go to an ignition point, such as a predetermined breaking point 6 , at the fuselage 5 and / or on an auxiliary fusible conductor 10 flow inside the fuse F.

By Inoniesierung the ignition of an arc takes place from further contact 3 to the fusible link 5 and / or the auxiliary fusible conductor 10 out.

Depending on the level of the resulting short-circuit current, the arc burns the auxiliary fusible conductor 10 and / or the fusible conductor 5 successively in the direction of the first (higher) potential L from or the or the fuse elements are abruptly evaporated to full length. Both operations result in the cancellation of the current according to the function and performance of fuses. Here is the area around the further contact 3 For example, so dimensioned that the ionization of a firing fusible conductor or auxiliary fusible conductor or the ionization through the plasma channel always leads to a powerful arc, both the fusible link 5 as well as the auxiliary fusible conductor 10 evaporated and the fuse completely triggers.

Thus, all current flows through the spark gap 8th interrupted. It is ensured that the spark gap 8th in the event of a fault, only that energy corresponding to i ² t has to be carried, which is used to melt and develop a first arc either on the auxiliary fusible conductor 10 or fusible link 5 necessary is. This energy is much lower than the energy up to extinguishing the fuse (forward integral) by the spark gap 8th would flow.

As a result, the fused circuit is greatly relieved.

If the fuse is ignited (triggered) by ionization via the plasma channel, generally an increased pressure which leads to rapid triggering of the triggerable fuse correlates with an excessively high pulse event, while the plasma input over a longer period of time coincides with the failure of the arrester on the supply network (Stream follower) correlates.

Furthermore, as in 2 shown the plasma channel 13 have a meandering structure. Ie. By shaping the plasma channel, the effect of plasma on the fusible conductor 5 (or also the auxiliary fusible conductor 10 ) are specifically controlled.

The design of the plasma channel can be realized in various ways. By varying the plasma channel length and plasma channel diameter, inserting meanders and / or intermediate volumes, and / or nozzles, a delay in the ignition and based on the energy input at the ignition point of the fuse an integrative effect can be provided.

The delay of the ignition can thus be adjusted so that they z. B. takes place only when a relevant excessively large amount of plasma in the spark gap 8th is generated, or one correspondingly smaller amount of plasma is generated over a longer period of time.

Alternatively or additionally, the plasma channel 13 a thermally degradable membrane or seal 14 exhibit.

It is characterized by the thermally degradable membrane or seal 14 similarly, a delay as previously described may be provided.

Preferably, the thermally degradable membrane or seal 14 made of a wax or plastic material. For example, polyoxymethylene (POM) can be used as the plastic material.

Particularly advantageous may also be provided that the fusible link 5 and / or the auxiliary fusible conductor 10 and / or the ignition circuit 9 with a quenching medium, in particular with sand and / or POM is filled. As a result, the switching characteristics in terms of the switching capacity and the speed are improved, since now an improved cooling of the arc is provided, whereby the switching capacity and the switching speed can be improved.

The combined surge protection device can be produced in a particularly cost-effective manner, if as in 2 shown, at least parts of the housing the same potential connection of the other connection 3 and provide the first main electrode FS ₁ . This can be z. B. be realized by a correspondingly conductive ausgestaltetes part housing.

Furthermore, the combined overvoltage protection device can be an auxiliary fusible conductor 10 having on the one side electrically connected to the first terminal A ₁ , wherein the auxiliary fusible conductor 10 on the other side over an ignition circuit 9 , which is arranged inside the housing, is connected to a starting auxiliary electrode HE.

Furthermore, the combined overvoltage protection device in the region of the auxiliary fusible conductor 10 an ignition region, which can be contacted with substantially equal potential to the second main electrode FS ₂ , so that in case of overload between the auxiliary fusible conductor 10 and the ignition area is an arc, which leads to a release of the fuse, and wherein the ignition circuit comprises a gas arrester and a varistor connected in series therewith.

In case of overload of the auxiliary melting conductor 10 arises in the area of rapprochement between the contact 3 and the auxiliary molten conductor 10 an arc between the ends of the fired auxiliary fusible conductor 10 , By means of this first arc, a second arc ignites between the fusible link 5 and the contact 3 which causes the fuse to burn off 5 , So leads to the triggering of the fuse F.

The ignition now melts the fusible conductor 5 and this breaks up.

In case of overload of the fusible conductor 5 , for example, due to overload currents or short-circuit currents, separates the fusible conductor 5 on and it creates an arc, which is initially between the two ends of the fuse conductor 5 burning. Under the action of the arc now burn the separated ends of the fuse conductor 5 gradually, with the arc lengthened. The ionization caused by the arc forms, if not already done, the further contact 3 as the (new) base of the arc.

Thus, the current flow through the spark gap 8th interrupted. This ensures that the spark gap 8th in the event of a fault, only that energy corresponding to i ² t has to be carried, which is necessary for the melting and development of the first arc. This energy is much lower than the energy that would flow through the device until the fuse (forward integral) is cleared.

As a result, the fused circuit is greatly relieved.

In an advantageous embodiment, the fusible conductor 5 and / or the auxiliary fusible conductor 10 in the area of further contact 3 a breaking point 6 on.

In a short circuit of the electrical device to be protected is now the fuse 5 in the area of the predetermined breaking point 6 melt. An arc is created and in turn the arc burns the two ends of the fuse conductor 5 and extends thereby. In the area of approach of contact 3 to the fusible link 5 it comes through the arc to an ionization, so that the arc, as a new base contact 3 or due to the low resistance (eg, with appropriate dimensioning) and / or arrangement relative to the second contact. Thus, the flow of current through the device to be protected 8th interrupted. This ensures that the device to be protected 8th in the event of a fault, only that energy corresponding to i ² t has to be carried, which is used to melt the predetermined breaking point 6 and the development of the first arc necessary is. This energy is much lower than the energy that would flow through the device until the fuse (forward integral) is cleared.

Particularly advantageous may also be provided that the fusible link 5 and / or the auxiliary fusible conductor 10 and / or the ignition circuit 9 with a quenching medium, in particular with sand and / or POM is filled. As a result, the switching characteristics in terms of the switching capacity and the speed are improved, since now an improved cooling of the arc is provided, whereby the switching capacity and the switching speed can be improved.

Furthermore, it can also be provided that the auxiliary fusible conductor 10 alternatively or in addition to the above-described ignition circuit 9 also a wear monitoring device 12 having.

The wear monitoring device 12 can z. B. be designed as protected with a degradable material contact.

Ie. in providing a firing circuit 9 and wear monitoring device 12 can both by overloading the ignition circuit 9 as well as by an overload of the spark gap 8th in their interior by triggering the auxiliary fusible conductor 10 and subsequently burning off the main molten conductor 5 the spark gap 8th completely disconnected from the network.

It may also be advantageous if at least the spark gap 8th is substantially pressure resistant umhaust. As a result, damage to surrounding equipment in the event of a failure can be avoided.

For the design of the fusible conductor 5 and the auxiliary smelting conductor 10 different embodiments may be provided. So like in the 1 and 2 shown, the fusible link 5 and the auxiliary fusible conductor 10 wire-like, at least in sections, be performed in parallel, or as in 3 shown on the left, the auxiliary fusible conductor can 10 as a part of the fusible link 5 be separated in sections. For example, the auxiliary fusible conductor 10 accordingly by stamping, separation, milling or the like of the fusible link 5 be separated in sections.

Or the auxiliary smelting conductor 10 can be like in 3 shown on the right, the auxiliary fusible conductor 10 in sections also helical the fusible link 5 surround.

In this case, the auxiliary fusible conductor 10 at least in the area of rapprochement of contact 3 to the Schmelzeiter 5 isolated from the fuse wire 5 run so that a substantially defined ignition point is present.

By a suitable embodiment of the further contact 3 and the fusible conductor 5 or auxiliary smelting conductor 10 the gap can be designed so that at a certain voltage, for. B. an overvoltage, it comes to a self-ignition. In this case, the gap and the further contact 3 and the fusible conductor 5 or the auxiliary fusible conductor 10 a second spark gap. Since this process is irreversible, the intermediate area is designed so that the specific voltage is higher, generally even higher, than the ignition voltage of the spark gap on the main electrodes FS ₁ and FS ₂ . In this respect, a quasi-second security level is added by the design.

In addition, the fusible link can 5 as well as the auxiliary fusible conductor 10 over one or more predetermined breaking points 6 in the area of further contact 3 or in the area of the fourth contact 4 feature. In a further embodiment of the invention, the further contact 3 designed like a disk, wherein the fusible conductor 5 and / or the auxiliary fusible conductor 10 is guided in a recess or through an opening. As a result, the production can be made particularly simple and thus cost. For example, the contact may be configured as a disk having a substantially circular opening. To introduce isolated potentials of further contact 3 The usual mechanisms for the isolated realization of potentials can be used. Particularly advantageous is the layered structure of metal plates and insulating plates with a Sicherungsendplatte for completion. In this structure, the various potentials can be introduced through the stacked insulated plates. The plate stack can, for. B. be bolted.

The triggering of the fuse can be signaled according to the usual mechanisms.

LIST OF REFERENCE NUMBERS

F

fuse

1

First contact

2

Second contact

3

Further contact

A ₁

First connection

A ₂

Second connection

5

fuse element

6

Breaking point

8th

radio link

9

ignition circuit

10

Auxiliary fuse element

12

wear detector

13

plasma channel

14

Membrane or seal

L

First potential

N

Second potential

FS ₁ , FS ₂

main electrodes

HE

auxiliary ignition

Claims (10)

Combined overvoltage protection device with an integrated spark gap ( 8th ) and with a fuse (F) connected in series therewith, wherein the series circuit can be connected to a supply network having a first potential (L) and a different second potential (N), the spark gap comprising two main electrodes (FS ₁ , FS ₂ ) comprising a housing having a first terminal (A ₁ ) and a second terminal (A ₂ ), wherein the first terminal (A ₁ ) is electrically conductively connected to the fuse (F), and wherein the second terminal (A ₂ ) electrically conductive with the first main electrode (FS ₁ ) of the spark gap ( 8th ), wherein the second main electrode (FS ₂ ) of the spark gap ( 8th ), is electrically connected to the fuse (F) inside the housing, wherein the fuse (F) is a fusible link (F) 5 ), which connects the first terminal (A ₁ ) to the second main electrode (FS ₂ ), wherein the fuse (F) further comprises another contact ( 3 ), the further contact ( 3 ) is isolated to the first terminal (A ₁ ) and isolated to the second main electrode (FS ₂ ) is arranged and in an untriggered state without contact to the fusible conductor ( 5 ), wherein the combined surge protection device further comprises a plasma channel ( 13 ), which from the combustion chamber of the spark gap ( 8th ) so in the vicinity of the fusible conductor ( 5 ) leads that plasma can affect the melting wire targeted degrading. Combined surge protection device according to claim 1, characterized in that the plasma channel ( 13 ) has a meandering structure. Combined surge protection device according to claim 1 or 2, characterized in that the plasma channel ( 13 ) a thermally degradable membrane or seal ( 14 ) having. Combined overvoltage protection device according to one of the preceding claims, characterized in that the plasma channel ( 13 ) a thermally degradable membrane or seal ( 14 ) made of a wax or plastic material. Combined overvoltage protection device according to one of the preceding claims, characterized in that the housing is at least partially filled in the region of the fuse (F) with an extinguishing material. Combined overvoltage protection device according to claim 5, characterized in that the extinguishing material is selected from the group comprising sand, POM. Combined overvoltage protection device according to one of the preceding claims, that at least parts of the housing are designed to be conductive to a potential equal connection of the further terminal ( 3 ) and the first main electrode (FS ₁ ). Combined overvoltage protection device according to one of the preceding claims, characterized in that at least the spark gap ( 8th ) is substantially pressure-resistant umhaust. Combined overvoltage protection device according to one of the preceding claims, characterized in that the fusible conductor ( 5 ) in the area of further contact ( 3 ) has a predetermined breaking point. Combined overvoltage protection device according to one of the preceding claims, characterized in that the further contact ( 3 ) is disc-like, wherein the fusible conductor ( 5 ) in a recess or through an opening of the further contact ( 3 ) is guided.

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