EP2064787B1 - Discharger arrangement for high measurement voltages - Google Patents

Abstract

The invention relates to a discharger arrangement for high measurement voltages, wherein at least two dischargers comprising opposing electrodes are connected in series, and at least one of the dischargers is active, that is, can be triggered, and having an overvoltage protection device for use as a grid arrester capable of bearing lightning current, for use as a grid arrester capable of bearing lightning current. According to the invention, the dischargers are located in an explosion-proof encapsulation having at least one pressure equalization opening. An insert bridging the distance between the main electrodes of the passive discharger is further made of a low-impedance material, wherein the low-impedance material has strongly non-linear behavior under current load with regard to off-peak residual voltage, wherein the overcurrent protection device further comprises a series circuit of a plurality of fusible elements forming a geometrically prescribed mechanical and electrical combination.

Description

The invention relates to a spark gap arrangement for higher rated voltages, wherein at least two spark gaps having opposite electrodes are connected in series and at least one of the spark gaps is active, i. triggerable, as well as with an overcurrent protection device for use as a lightning current carrying mains arrester, according to the preamble of patent claim 1.

A series circuit of two spark gaps for the limitation of surges in low-voltage systems, consisting of three electrodes, wherein for the creation of each spark gap, two of these electrodes are each opposite to a surface and are held apart by an insulating layer, is from the DE 39 14 624 C2 previously known. The local spark gaps have a very different inherent capacity, whereby the response voltage of the overall arrangement is determined essentially by the spark gap with the smaller capacity.

From the DE 42 40 138 A1 a Ausblasende spark gap is previously known, in which in series with a short spark gap with insulation material one or more spark gaps are connected in series with low-resistance material. In this case, the spark gap with the insulating material defines the response voltage of the overall arrangement.

At the lightning current carrying multiple spark gap after EP 1 381 127 A2 is assumed by several, connected in series partial spark gaps, the partial spark gaps, with the exception of the lightning current event case first responding spark gap are connected by impedances, so that they switch through successively. The second and the further spark gaps are connected via the impedances directly to a common reference potential. With the spark gap presented there, the response voltage should be reduced. For this is at least the Electrodes of one of the partial spark gaps applied a trigger voltage, by means of which the partial spark gap is forced to turn on.

Similar arrangements with several partial spark gaps are in the WO 07/003706 and the US 4,860,156 B1 for high voltage applications.

From the DE 10 2004 006 988 A1 is a spark arrestor overvoltage protection element with at least two located in a pressure-tight housing main electrodes and a Zündhilfselektrode, wherein in the housing volume, a functional assembly is housed to reduce the Ansprechspannung. This functional module comprises a series connection of a voltage-switching element, an impedance and an isolating distance, so that a simplified, quasi-integrated starting aid is created.

In summary, it belongs to the known state of the art to make spark gaps suitable for use at higher rated voltages by series connection. A simple series connection leads to triggerable spark gaps in addition to the considerable costs to restrictions in terms of protection level and the coordination of the arrester and usually requires an additional complex potential control.

From the DE 199 14 313 A1 is the hedge of a starting aid a spark gap previously known. In this case, fuses or reversible fuses are used. The melting of the fuse is used with the aid of electronic circuits for optical, acoustic and / or electronic display.
After the fuse has responded, the spark gap should be able to exert a redundant protective function with an increased protection level without an ignition aid. Derivation of a display function from the shutdown behavior of fuses is beyond the DE 38 31 935 A1 , of the DE 197 51 470 A1 or the DE 32 28 471 A1 previously known.

The U.S. Patent 6,157,529 discloses the interruption of a circuit by means of the disconnection of a fuse and a holding coil of a switch.

Ignition aids, as in the DE 199 14 313 A1 described, are also used in combination arresters. With these arresters, the starting aid itself can be designed as an independent overvoltage protection device, which activates the short-circuit element, generally a spark gap, only at the risk of its own overload via a trigger function. A combination arrester is for example in the DE 198 38 776 C2 shown.

A spark gap arrangement according to the preamble of claim 1 is also made DE-A-2 406 577 known.

From the foregoing, it is therefore an object of the invention to provide a further developed spark gap arrangement for higher rated voltages, wherein at least two spark gaps having opposite electrodes are connected in series and at least one of the spark gaps is active, ie. Triggerable is executed. According to the invention, with regard to the response and the coordination, only the triggerable, i. active spark gap of the overall arrangement dominate. When line sequencers occur, the arrangement should act like a conventional series of spark gaps. The arc voltage is composed of the partial voltages of the two spark gaps and it is divided even after the current zero crossing the recurrent mains voltage on the spark gaps. It is the task, between the triggered and the passive, i. not active spark gap to secure a load-dependent division of functions.

The object of the invention is also to provide an overcurrent protection device for use in overvoltage protection devices based on spark gaps with higher rated voltages in the range of 440 V to 760 V and more, in combination with a mechanical trigger for a display and fuses for overload protection , The possibility should be created, using geometrically identical housing, display and mounting parts at different voltage levels to make an economical and functional meaningful design of the active parts, so that an easy adaptability to different uses and applications is given.

The object is achieved by a spark gap arrangement according to the feature combination according to claim 1, wherein the dependent claims represent at least expedient refinements and developments.

In the series connection according to the invention spark gaps are used, which are located in a flameproof enclosure and which have at least one pressure equalization opening. Furthermore, a distance of the main electrodes of the spark gap bridging insert is provided, which consists of a low-resistance material. This material behaves strongly under current load with respect to the decreasing residual voltage nonlinear.

In a first embodiment variant, the series connection is formed from two physically separated spark gaps, one of the spark gaps being triggerable and the second spark gap being passive. In a further embodiment, the spark gaps are accommodated in a common, pressure-resistant, preferably metallic housing and it is possible to use two active, triggerable spark gaps for voltages of substantially 760 V.

The spark gaps preferably used are rotationally symmetrical. The respective opposing main electrodes comprise a main electrode with Gasumlenkkanal. With regard to the basic construction of the spark gaps used, reference is made to the teaching according to the patent DE 10 2005 024 658 B4 to which reference is hereby incorporated by reference.

Between the opposing main electrodes of the at least one passive spark gap, the bridging, low-impedance insert already mentioned is arranged as a preferably rotationally symmetrical part with a cylindrical opening defining the arc combustion chamber. The main electrode opposite the main electrode with the gas deflection channel has a nose portion or a projection which dips into the cylindrical opening, with the wall coming into contact with it. It is understood that the nose portion is to be formed in its outer contour complementary to the shape of the cylindrical opening.

The low-resistance material of the insert preferably has a cold resistance of <100 ohms.

The insert has in one embodiment, a hollow cylindrical shape and is located with one end face over the entire surface of the main electrode with Gasumlenkkanal.

Furthermore, there is the possibility that the preferably hollow-cylindrical insert, in each case with one of its end faces, is in contact with one main electrode in each case over its entire surface.
In this embodiment, the flashover between the main electrodes takes place only after a comparatively longer period of time or at very high pulse currents, which is of particular interest when the residual voltage of the spark gap is to be above the rated voltage for a plurality of pulse-shaped discharges in order to prevent a Netzfolgestrom ,

The clear distance between the respective main electrodes of the spark gaps is substantially greater than that which can be found in the known state of the art in corresponding series circuits, and is at least about 5 mm.

The pressure equalization openings are basically oriented in the axial direction of the rotationally symmetric spark gaps and are away from one another in order to prevent unwanted exposure of functionally important parts.

Between the rotationally symmetric part with cylindrical opening and the main electrode with nose section, in a further embodiment, a transition part may be provided which has a higher resistance value relative to the insert, but is conductive.

The geometric shape of the insert can be subjected to changes in the radial and / or axial direction for adjusting and varying the current density, so that in the preferred rotationally symmetric Basic construction and a desired modular structure by replacing the insert various electrical parameters can be realized.

In an arrangement of two spark gaps in a common, pressure-resistant housing, a common central main electrode is preferably provided, which in this case is insulated from the jacket encapsulation.

The pressure compensation openings are designed axially and opposite in the region of the external contact of the respective main electrode as channels of small cross section for the slow pressure reduction of the already cooled gas. Also based on the design of the pressure equalization channels and the meandering deflection of the gas flow is to the patent application DE 10 2007 001 093.3 which is hereby declared and introduced the subject of the present application.

The external trigger circuit for igniting the active spark gap is guided on the trigger electrode of this active spark gap and on the electrical end connection points of the series connection.

With the proposed spark gap arrangement, it is possible to standard standard spark gaps in encapsulated, pressure-resistant design with pressure equalization openings for higher nominal voltages through series connection, in a simple basic variant, only a single triggered spark gap is connected in series with a single passive spark gap. In the teaching of the invention, the necessary follow current limiting is achieved by increasing the arc field strength due to the pressure increase or in combination with the arc cooling by flowing the arc within encapsulated spark gaps. The distances between the main electrodes are at least 5 mm. The low-resistance material of the insert is located within the passive spark gap directly in the region of the arc channel and radially or completely limits the wall-stabilized arc.

The material bridging the gap between the main electrodes of the passive spark gap has a cold resistance of less than 100 ohms and behaves at current load with respect to the decreasing residual voltage is not very linear, ie the voltage drops despite further increasing current. The material used can briefly cause pulsed currents of several kA without lasting damage until overturning. The resulting residual voltage is well below 2 kV. The height and the duration of the residual stress can also be set or influenced by influencing the current density distribution in the material itself, by the geometric design of the insert or else by a functional subdivision from a plurality of materials.

The inventive passive spark gap does not affect the response, coordination and residual voltage behavior of the entire series connection. The subdivision into partial spark gaps reduces the thermal and dynamic load on each single spark gap and there are many design options. The performance of the series-connected lightning arrester is improved in terms of follow current limiting, lightning current carrying capacity and aging. Compared to a series connection of two triggerable arresters, there is the advantage that both space and costs for the second or multiple ignition units can be saved. In a conventional series connection of triggerable spark gaps namely either a simultaneous ignition must be done, which makes high demands on the spark gaps, the trigger circuit and the potential control, or the trigger circuit must be able to compensate the Zündverzugszeiten the individual spark gaps, since usually trigger circuits only one time and energy provide limited ignition pulse. By using one or more passive spark gaps in the embodiment of the series connection according to the invention, the costs for additional ignition circuits can be saved.

Based on the presented basic design of the series connection of spark gaps, it is possible to produce arresters for 440 V as well as for 760 V voltages. The arrester has a passive spark gap for the 440 V level and a triggerable spark gap connected in series with a trigger circuit.

For devices with higher voltage, two triggerable spark gaps are connected in series. The corresponding trigger circuits are provided on the control board described in the embodiment. The remaining means such as fuse elements and the display units are identical, i. There are no significant differences between the 440 V / 760 V arresters.

Another basic idea of the invention is to divide the fuse elements for the spark gap arrangement, in particular fusible elements, into a series connection of a plurality of fuses, which, in addition to the electrical connection, are partially in a mechanical series connection and partly in a mechanical parallel connection. By thus made division of the fuse arrangement arise various possibilities of geometric design and thus for optimal space utilization in otherwise used standard housings.

The division also allows a large variance in terms of residual voltage behavior, rollover protection, current limitation, the actual performance and the necessary distances to vulnerable other components, in particular a trigger circuit.

As already stated, according to the invention a series connection of a plurality of fuse elements is provided which form a geometrically predetermined, mechanical and electrical connection.

In one embodiment, this series connection has a mechanical and electrical parallel connection of fusible elements, wherein at least one of the fusible elements of the parallel connection comprises a firing pin as a mechanical trigger for actuating a function display.

A first part of the series combination is located on one side of a wiring substrate, in particular a printed circuit board, and a second part of the series compound is located on a second, the first opposite side of the wiring substrate.

The first part of the series composite comprises at least two cylindrical individual fuses, which are mechanically and electrically connected by a conductive cylinder on the end faces and connecting caps present there. This mechanical and electrical connection with the aid of the conductive cylinder takes place only in the area of the mechanical connection caps, so that the insulation and separation distances are maintained.

The composite of the cylindrical individual fuses with the conductive connecting cylinder may be coated by an insulating material, in particular by a shrink tube.

The second part of the series network comprises the already mentioned parallel network, wherein the parallel network is predominantly surrounded by a protective housing to which further functions, which are described below, can be assigned.

The connection caps of the fusible elements of the parallel connection are electrically and mechanically connected and merge into a connection extension, which in each case allows mounting on the wiring carrier.

The free ends of the individual fuses of the first part of the series composite also have connection caps with Lötfähnchen or tab-like extensions.

To adapt to the nominal voltage ranges, it is possible to replace one or more of the individual fuses or fusible elements by a conductive, in particular metallic, geometrically diameter-matched cylinder. The cylinder may also have a predetermined impedance.

In a preferred embodiment, the wiring carrier has an elongate, rectangular shape with screw connection lugs attached to the narrow sides.

The first part of the series composite is at a longitudinal outer edge, with this substantially laterally terminating, located on the wiring carrier.

The second part of the series composite, containing the parallel connection, is arranged essentially at right angles to the longitudinal axis of the first part of the series combination on the wiring carrier.

The protective housing is open to the longitudinal edge of the wiring substrate, to allow an exit of the firing pin and an operative connection of the firing pin towards a spring-biased indicator slide.

The protective housing has on its upper side facing away from the wiring substrate a color-coded indicator surface or an indicator surface extension, which is integrally formed on the housing. In this way, based on a viewing window in a cap or an outer housing, which reveals a view of the top of the protective housing, a functional state can be displayed by a slide either the view of the top releases or blocks this view.

So it has the protective housing on the one hand, the function of the isolation of the parallel compound and serves the purpose of retaining elements in the event of triggering this fuse. Furthermore, the housing serves for the aforementioned formation of an indicator surface or the reception of an indicator surface extension.

The wiring carrier is preferably mountable on the upper side of a housing, wherein the housing accommodates in its interior an arrangement of surge arresters, in particular spark gaps. This arrangement of surge arresters, in particular spark gaps is in series connection.

One of the spark gaps of the device may be triggerable, in which case the trigger circuit is on the wiring carrier.

The housing for receiving the spark gaps has on its upper side over a longitudinal edge a trough-like recess into which the first Part of the series composite dips to effect in this way a protective and insulating function of the first part of the series compound.

The overall arrangement of housing-mounted spark gaps, located on the top of the housing wiring substrate with electrical elements and the series circuit of a plurality of fuses is surrounded by an insulating cap, the cap having the aforementioned window for detecting the functional state with respect to the indicator surfaces.

The overcurrent protection device is characterized by a modular design with selected fuses for series connection to cause easy adaptation to different rated voltages.

The display slider, which is spring-biased and can be released from the firing pin of the parallel connection, has a display surface which releases or obscures a color-deviating indicator surface, in particular the indicator surface of the top of the protective housing.

Furthermore, the display slider has an extension, which extends in the longitudinal direction beyond the narrow side of the wiring substrate, in order to interact there with a telecommunications contact in operative connection.

The fusible elements which can be used in the series connection of the overcurrent protection device consist of individual fuses which are inexpensive to manufacture, in each case, for example. for a voltage level of 250 V.

For the first part of the series connection, at least two of the fuses are connected together by a precisely fitting cylinder. The cylinder may preferably be a metal cylinder, which in addition to the electrical connection also takes over the mechanical fixing and the necessary mechanical stabilization of the corresponding part of the series connection. The number of connection elements is lower by this type of connection than in a simple series connection of individual electrical fuses, which are each connected, for example, by soldering to a circuit board.

The distance between the remaining connection elements or end caps of the fuses is considerable, which makes it easier to maintain separation distances and significantly reduces the risk of bridging.

The preferred arrangement of the above-described series connection on the underside of the wiring substrate also provides space on the component side, in addition to sufficient separation distances on the wiring substrate. the opposite side, on the one hand on the volume savings and on the other hand by avoiding critical approximations between the overload-endangered elements and the protective device.

The first part of the series connection is separated at the top by the board from the components of the ignition circuit and on the bottom by the trough-like expression of the housing. This results in a quasi a complete insulating enclosure of the protective device. This prevents in the event of an error Berußung that may occur, and it will protect the separation sections of the ignition circuit when the release of gas or plasma from the fuse from flashovers.

The parallel part arrangement representing the second part of the series combination is preferably designed as in the German patent application DE 10 2006 026 711.7 described.

The fuses used as fuses of the parallel connection and also of the series combination preferably have the same fusible conductor at maximum rated voltage. This ensures an almost simultaneous response of all fuses for adiabatic loads and loads in which the axial heat dissipation dominates over the radial heat output.

The characteristic of the series connection of the fuses thus corresponds to a partial area fuse. The dimensions of such a series connection are considerably smaller with comparable switching capacities than with individual fuses, eg for a rated voltage of 690 V.

In addition to the above-mentioned space saving allows the division of the fuse into several subunits and a very flexible arrangement of the individual functional units with respect to the position and location with respect to the wiring substrate.

At desired lower rated voltages, one or more fuses of the series assembly can be replaced by a simple metallic cylinder. In addition to the cost reduction, this also leads to a reduction of the residual voltage and thus supports the desired basic function of the arrester. By a two-sided arrangement of metal cylinders in addition to a real fuse in the series combination also the current force effect can be reduced to the fusible conductor, whereby higher pulse currents can be supported.

Through the use of the above-mentioned impedance-affected cylinder and the requirements for the switching capacity of the actual fuse can be reduced, since the prospective short-circuit current is limited by the impedance.

The invention will be explained below with reference to exemplary embodiments and with the aid of figures.

Fig. 1

eine Reihenschaltung einer getriggerten Funkenstrecke und einer passiven, ungetriggerten Funkenstrecke als diskrete Elemente in jeweils druckfester Kapselung;

Fig. 2

eine beispielhafte Geometrie einer passiven Funkenstrecke, wie sie für die Reihenschaltung gemäß der Erfindung zur Anwendung kommt;

Fig. 3

eine weitere Ausführungsform einer Geometrie einer passiven Funkenstrecke, wie sie erfindungsgemäß bei der Reihenschaltung zur Anwendung kommt;

Fig. 4

eine besonders bauraumsparende Anordnung einer getriggerten und einer passiven Funkenstrecke in einer gemeinsamen, metallischen druckfesten Kapselung mit gegenüberliegenden Druckausgleichsöffnungen in Form von Kanälen kleinen Querschnitts,

Fig. 5 und 6

eine Darstellung des ersten Teils des Reihenverbunds von Schmelzelementen;

Fig. 7

eine Draufsicht auf das Gehäuse mit eingeschlossenen Funkenstrecken und erkennbarer muldenartiger Ausnehmung an der Oberseite des Gehäuses;

Fig. 8

eine Seitenansicht einer Anordnung mit Gehäuse sowie Verdrahtungsträger, welche u.a. die Triggerschaltung sowie die Überstromschutzeinrichtung aufnimmt;

Fig. 9

eine Darstellung ähnlich derjenigen nach Fig. 8, jedoch in perspektivischer Form und

Fig. 10

eine Darstellung der Reihenschaltung der Funkenstrecken im Gehäuse 112.

Hereby show:

Fig. 1

a series connection of a triggered spark gap and a passive, ungetriggered spark gap as discrete elements in each flameproof enclosure;

Fig. 2

an exemplary geometry of a passive spark gap, as used for the series circuit according to the invention;

Fig. 3

a further embodiment of a geometry of a passive spark gap, as used according to the invention in the series connection;

Fig. 4

a particularly space-saving arrangement of a triggered and a passive spark gap in a common, metallic flameproof enclosure with opposite pressure equalization holes in the form of channels of small cross-section,

FIGS. 5 and 6

a representation of the first part of the series of fused elements;

Fig. 7

a plan view of the housing with enclosed spark gaps and recognizable trough-like recess at the top of the housing;

Fig. 8

a side view of an arrangement with housing and wiring support, which includes, inter alia, the trigger circuit and the overcurrent protection device;

Fig. 9

a representation similar to that after Fig. 8 , but in perspective and

Fig. 10

a representation of the series connection of the spark gaps in the housing 112th

The Fig. 1 shows a series connection (sectional view) of a triggered spark gap 1 (active spark gap) and an ungetriggered (passive) spark gap 2.

The trigger circuit 3 of the active spark gap 1 has a connection 4 which is connected to a connection 5 of a main electrode 8 of the passive spark gap 2. Another connection of the trigger circuit 3 leads to the main electrode 8 of the active spark gap 1, the also has the trigger contact through an insulation 20, led out of the pressure-resistant metallic encapsulation 21 has.

Pressure compensation openings 6 of the spark gaps 1 and 2 and the gas flow direction 7 (arrow) within the spark gaps 1 and 2 are oriented opposite.

Both spark gaps 1 and 2 each have a plurality of independent ventilation openings 6 for better control of the flow and for effective cooling of the gases formed during ignition and firing of the arc. In each case one of the main electrodes 8 has an opening 22, which forms part of a Gasumlenkkanals, which merges into the pressure equalization openings 6.

The triggerable spark gap 1 has two main electrodes, namely the main electrode 8 and 9, and an auxiliary electrode 10, which is in electrical connection with the trigger contact 20.

Furthermore, the spark gap 1 has at least one insulation gap 12, which is located between the main electrodes 8 and 9 of this spark gap.

The passive spark gap 2 also has two main electrodes 8 and 9. A trained as a spacer 13 insert between the main electrodes 8 and 9 of the passive spark gap is preferably made in one piece from a very low-resistance material. With a preferred geometry of d = 15 mm, di = 5 mm and h = 5 mm results in a test current of a few mA, a cold resistance of <100 ohms.

The spacer 13 is preferably designed as a hollow cylinder and lies according to the illustration Fig. 1 with one of its end faces over the entire surface on the main electrode 8. In the interior of the insert 13, that is, there existing cylindrical opening, protrudes a nose portion 23 of the main electrode 9, resulting in a radial contact with the insert or the spacer 13 results.

The spacer 13 is to prevent flashovers in the contacting region between the nose portion 23 of the main electrode 9 and the plate-shaped electrode holder 14 is insulated from the latter via the part 15.

The immersion depth of the nose portion 23 of the electrode 9 in the spacer 13 increases with the desired level of performance of the arrester and decreases with increasing erosion resistance of the electrode material. The immersion depth is in this case dimensioned such that both the axial burnup of the nose electrode 9 and the radial erosion of the spacer 13 do not lead to an insulating separation path between the parts 13 and 9.
After the response of the spark gap 1 at pulse load, a current flows up to several kA via the spacer 13 until the path between the electrodes 8 and 9 of the passive spark gap 2 is skipped. Due to the non-linear behavior of the material of the spacer 13, only a small residual stress is generated over the material of the spacer 13, which does not increase the protection level of the entire arrester.

However, due to manufacturing and material tolerances, contamination or extreme stress contact problems or a changed rollover behavior of the spacer 13 may occur, which may result in undesirable repercussions on the residual stress of the arrester. This can be compensated for high demands on the height and duration of the residual voltage of the arrester by an integrated in the trigger circuit 3 overvoltage fine protection and by the type of contact, which includes the passive spark gap.

With reproducible manufacturing and material properties or not particularly high stresses and / or lower demands on the protection level, the contacting of the trigger device between the two spark gaps, so only at the terminals of the spark gap 1, take place.

The height and duration of the current through the spacer 13 as well as the rollover behavior can be influenced by the control of the current density and the current distribution in the spacer 13 in addition to the material properties of this part. This can in addition to influencing the Residual voltage can also be used to control the power conversion, the burnup and the thermal load of the spark gap and in particular of the insert 13. The main electrodes 8 and 9 of the passive spark gap 2 can be completely or partially isolated from the spacer 13.

The Fig. 2 shows an exemplary geometry as a cross-sectional representation of a passive spark gap. Again, two opposite main electrodes 8 and 9 are present. The electrodes are isolated in a metallic enclosure 21 located.

The main electrodes 8 and 9 shown can also be isolated from the insert 13, but the breakdown voltage of the insulation must be well below the desired protection level and below the residual voltage of the trigger circuit.

As an alternative to insulation, a defined transition region with a thin and with respect to the spacer 13 high-resistance, but electrically conductive layer 16 is possible. Both measures described require a higher current density at the quasi-channel inside of the designed as a hollow cylinder spacer 13 and lead to an accelerated rollover behavior. In addition, a pre-ionization in the isolated or high-impedance range is effected.

The spacer 13 can also be varied in the circumference of the hollow cylinder in both the radial and in the axial direction with respect to the electrical conductivity. In this way, in addition to the control of the electric current density in the spacer 13 and effects of thermal insulation with respect to the electrodes 8 and 9 are effected. In addition, the variation of the materials in the discharge channel can serve the function division or be used to influence the temperature and pressure resistance and the better aging quality and to reduce the burnup.

The Fig. 2 shows here, for example, a substantially only axial function distribution. In contrast to the representation after Fig. 1 are according to Fig. 2 the electrodes 8 and 9 with respect to the metallic encapsulation 21 isolated.

The Fig. 3 shows a further embodiment of a possible geometry in cross-sectional view for the passive spark gap. 2

In this spark gap 2, a flashover between the main electrodes 8 and 9 should be done only at a comparatively long period of time or very high pulse currents.

This is of particular interest if the residual voltage of the spark gap 2 is to be above the nominal voltage in the case of a large number of pulse-shaped discharges in order to prevent a line following current.

For this purpose, the spacer 13 is contacted on both sides of the entire surface with the respective main electrodes 8 and 9 in order to effect a largely homogeneous current density within the spacer 13. In addition, increases in the electric field strength, in particular in the rollover area can be avoided.

With the help of Fig. 4 Let us illustrate a basic embodiment of two spark gaps in a cross-sectional view, which are located within a common metallic encapsulation 21.

Both spark gaps have a common center electrode 9, which is insulated from the flameproof enclosure 21. In the area of the passive spark gap 2, however, there is a low-resistance connection to the main electrode 8 there. In contrast to the representation after Fig. 1 in which in each case one main electrode is in direct contact with the metallic sheath 21 in both spark gaps 1 and 2, at least one of the spark gaps 1 and 2 is shown in FIG Fig. 4 both main electrodes with respect to the jacket or the enclosure 21 isolated.

As shown Fig. 4 This is the case with the passive spark gap 2. Alternatively, the spark gap 1 or both Spark gaps are performed with insulating main electrodes 8 and 9. The insulation of the main electrodes 8 and 9 is preferred over an insulating interruption of the pressure-resistant metallic shell 21 due to a better overload behavior. The spark gaps accordingly Fig. 4 own as well as in Fig. 1 represented, opposite venting and pressure equalization openings or channels 6.

The main electrodes each have at least a distance of substantially 5 mm in both spark gaps 1 and 2. The pressure in the discharge region, which is completely or partially enclosed by the insert 13, is up to several 100 bar in the case of impulse and subsequent static discharges. For prospective net sequence currents in the range of> 500 A to several kA, pressures of at least 10 bar are achieved.

To control the operating voltage and to ignite the spark gaps no complex and overload-endangered, external, additional capacitive or resistive voltage control is required, which would also need to be tuned over the entire relevant frequency range. The illustrated series circuit of two spark gaps can basically be extended as desired.

The series connection of a spark gap with insulation and a quasi-shorted spark gap has compared to two spark gaps, each with isolated separation distance per se the disadvantage that only one separation section provides an immediate consolidation after the current zero crossing. The instant solidification voltage is in the range of about 300 V. When using such a spark gap at higher operating voltages, especially at voltages above the instant solidification voltage, there is a risk of reignition. In order to be able to work with only one insulation distance, despite this disadvantage, the effect is used that the spark gaps used make use of the pressure increase that forms to delete the secondary current. By using the pressure to extinguish the follow-on current, even after the current zero crossing, in particular with a gradual pressure reduction, it is possible to make the relatively high pressure effective for increasing the dielectric strength of the separation gap. The dielectric strength after The current zero crossing can thus be increased proportionally with the pressure increase, whereby reignifications are avoidable. This surprisingly allows the use of the proposed spark gap combination even at nominal voltages well above the instantaneous consolidation voltage for a separation line.

The used overcurrent protection device comprises a series connection of a plurality of fuse elements, which form a geometrically predetermined, mechanical and electrical composite.

A first part of the series composite comprises two individual cylindrical fuses 100 and 200. These two individual cylindrical fuses 100 and 200 are mechanically and electrically connected, for example, by a conductive, preferably metallic cylinder 300 on the end faces 400 and terminal caps 500 present there. connected by clamping or soldering.

The resulting composite of the cylindrical individual fuses 100 and 200 with the connecting cylinder 300 is coated with an insulating shrink tube 600 (see Fig. 6 ).

The free ends of the individual fuses 100 and 200 likewise have connection caps 500, but with soldering lugs 500a, which serve for electrical connection and mechanical fixing on a printed circuit board.

The series circuit also includes a mechanical and electrical parallel composite of fusible elements, wherein at least one of the fusible elements of the parallel compound has a firing pin as a mechanical trigger. The mechanical release can be embodied as a wire-shaped release part, whereby preferably this wire of the release part is connected in parallel over a part of the entire overcurrent protection device, which has the advantage that the coordination of the current commutation and the switching capacity is limited to this part of the protection.

In a parallel circuit to the entire fuse arrangement, ie parallel to all partial fuses, would have the fuse element of the indicator fuse have the full switching capacity, which is possible, but leads to higher costs.

In one embodiment, the fusible link of the fuse to which the indicator is connected in parallel may be provided with a minimally lower fuse integral to ensure a reliable indication even at low overloads.

Since the complete outgassing of the indicator fuse or the throwing away of parts of the indicator can be avoided only with great effort, there is basically the danger of the outer flashover of the fuse arrangement at high voltages.

To counteract this danger, the indicator part, ie the parallel connection, with an additional housing 700 (see Fig. 8 and 9 ) Mistake.

This housing 700 blocks the external flashover and greatly reduces the danger that can arise from released indicator parts (striker).

Like from the Fig. 8 As can be seen, the housing 700 is preferably arranged at right angles to the longitudinal axis of the wiring substrate 800.

The first part of the series assembly 900, including the connection cylinder and protective cover individual fuses, is located on the underside of the wiring substrate 800, with the second part of the array, located in the housing 700, being placed on top of the wiring substrate 800.

From the illustration to Fig. 9 It can be seen that the wiring support 800 has an elongated, rectangular shape with screw connection lugs 110 attached to the narrow sides, wherein the first part of the series assembly 900 is located at a longitudinal outer edge, substantially laterally terminating therewith.

The protective housing 700 is open to the longitudinal edge of the wiring substrate 800, to allow escape of the firing pin therein and an operative connection to a spring-biased indicator slide 111.

The protective housing 700 has on its upper side remote from the wiring support 800 a color-coded indicator surface, e.g. red, or has an indicator surface extension extending from the housing 700.

The wiring carrier 800 is mountable on top of a housing 112, wherein the housing 112 may be a series spark gap arrangement.

The advantages of the housing construction with regard to the creation of separate, mutually isolated subregions should be made with reference to Fig. 7 to 10 will be explained below.

Sheathed portions are the top of the wiring substrate 800, the groove-shaped recess 114, the spark gap housing 112 and the fuse housing 700 to see. The area of the carrier board and the fuses is protected from the spark gap housing 112 by an insulating partition plate from staining or contamination from this area. The fuse in the groove-shaped recess 114 is thus, in addition to the contaminants from the region of the wiring substrate 800, also sealed off from the spark gap housing 112. Thus, neither impurities from the spark gap area nor contamination from destroyed components on the wiring carrier can affect the switching capacity of the fuse 900.

The other part of the series connection of the fuses is protected by the housing 700 for the parallel connection from being exposed from the wiring support and at the same time can not cause arcing on the wiring support.

At least one spark gap of the spark gap arrangement can be triggered and the trigger circuit can be located on the wiring carrier. The contacting between the wiring carrier and the spark gap to be triggered can take place via a contact spring which extends through a recess 113 in the housing 112 ( Fig. 7 ).

Furthermore, the spark gap housing 112 has on its upper side a trough-like recess 114, in which the first part 900 of the series combination dips to effect a protective and insulating function (see Fig. 7 and 8th ).

The overall assembly may be surrounded by an insulating cap, the cap having a viewing window to allow a view of the top of the housing 700 and the indicator slide 111, respectively.

The display slider 111 has a display surface 115. This display area may e.g. have a green color that signals the condition "in order".

If the display slider moves as shown in the illustration Fig. 9 to the left, the underlying top of the housing 700, which is designed differently colored, released and signaled an error condition.

The display slide 111 also has an extension 116 which extends in the longitudinal direction over the narrow side of the wiring substrate 800, to communicate with a telecommunications contact 117 in operative connection.

In the region of the extension 116 of the indicator slide 111 has a thorn-like shape, which receives a helical compression spring, which is supported against the spark gap housing 112 to produce the necessary bias.

LIST OF REFERENCE NUMBERS

1

active spark gap

2

passive spark gap

3

trigger circuit

4

connection

5

Main contact / connection

6

Pressure equalization port

7

Gas flow direction

8th; 9

main electrode

10

auxiliary electrode

12

insulating gap

13

Insert or spacer

14

plate-shaped electrode holder

15

insulation part

16

high-resistance, electrically conductive layer

20

Isolation for trigger contact

21

metallic, flameproof enclosure

22

Opening in Gasumlenkbereich a main electrode / Gasumlenkkanal

23

nose section

100; 200

cylindrical single lock

300

connecting cylinder

400

front

500

connection cap

500a

Lötfähnchen

600

coating

700

Housing for parallel connection

800

wiring support

900

first part of the series network

110

Schraubanschlusslasche

111

display slide

112

Spark gap housing

113

Recess for trigger contact

114

trough-like recess

115

display area

116

extension

117

telecomm

180

indicating surface

Claims (15)

1. Spark gap arrangement for higher rated voltages, wherein at least two spark gaps having opposite electrodes are connected in series and at least one of the spark gaps is configured actively, i.e. triggerable, and comprising an overcurrent protector for use as a mains arrester capable of carrying lightning current,
   characterized in that
   the spark gaps (1; 2) are located in a pressure-resistant encapsulation (21) having at least one pressure compensation opening (6), and an insert (13) bridging the spacing of the main electrodes (8; 9) of the passive spark gap (2) is made of a low-impedance material which, when subjected to an electrical load with respect to the decreasing residual voltage, has a strong non-linear behavior, wherein the overcurrent protector includes a series connection of several fuse elements which form a geometrically predefined mechanical and electrical interconnection.
2. Spark gap arrangement according to claim 1,
   characterized in that
   the spark gaps (1; 2) are each separately enclosed by a pressure-resistant encapsulation (21), wherein the pressure compensation openings (6) are oriented to be facing away from each other.
3. Spark gap arrangement according to claim 1,
   characterized in that
   the spark gaps (1; 2) are enclosed by a common pressure-resistant housing (21) which is provided with the pressure-compensation openings (6).
4. Spark gap arrangement according to one of the preceding claims,
   characterized in that
   the spark gaps (1; 2) are configured rotationally symmetrically and the respective main electrodes (8; 9) are disposed opposite each other and one of the main electrodes (8) comprises a gas deflection channel (22), that further between the opposite main electrodes (8; 9) of the at least one passive spark gap (2) the bridging, low-impedance insert (13) is arranged as a rotationally symmetrical part having a cylindrical opening that delimits the arc combustion chamber, wherein the main electrode (9), which is disposed opposite the main electrode having the gas deflection channel (22), has a nose section (23) which immerses into the cylindrical opening by contacting the wall of the same.
5. Spark gap arrangement according to claim 4,
   characterized in that
   a transition part (16) is provided between the rotationally symmetrical part having the cylindrical opening and the main electrode having the nose section (23), which has a higher resistance value as compared to the insert (13) and is conductive.
6. Spark gap arrangement according to one of claims 3 to 5,
   characterized in that
   if two spark gaps are arranged in a common pressure-resistant encapsulation (21), a common center main electrode (9) is provided which is insulated with respect to the encapsulation (21).
7. Spark gap arrangement according to one of the preceding claims,
   characterized in that
   the series connection comprises a mechanical and electrical parallel interconnection of fuse elements, wherein at least one of the fuse elements of the parallel interconnection has a striking pin as mechanical trigger.
8. Spark gap arrangement according to claims 1 and 7,
   characterized in that
   a first part (900) of the series interconnection is located on one side of a wiring carrier (800) and a second part of the series interconnection is located on a second side of the wiring carrier (800) which is disposed opposite the first one.
9. Spark gap arrangement according to claim 8,
   characterized in that
   the first part of the series interconnection comprises at least two cylindrical individual fuses (100; 200) which are mechanically and electrically connected by a conductive cylinder (300) on the front sides (400) and connecting caps (500) provided thereat.
10. Spark gap arrangement according to claim 9,
    characterized in that
    the interconnection of cylindrical individual fuses (100; 200) is covered by an insulating heat-shrinkable sleeve or the like material (600).
11. Spark gap arrangement according to claim 9 or 10,
    characterized in that
    the free ends of the individual fuses (100; 200) comprise connecting caps (500) with soldering tags (500a).
12. Spark gap arrangement according to one of claims 8 to 11,
    characterized in that
    the wiring carrier (800) has an elongated rectangular shape with screw connection lugs (110) mounted on the narrow sides, wherein the first part (900) of the series interconnection is arranged on a longitudinal outer edge substantially laterally flush with the same, and the second part of the series interconnection, including the parallel interconnection, is arranged on the wiring carrier (800) substantially orthogonally with respect to the longitudinal axis of the first part (900) of the series interconnection.
13. Spark gap arrangement according to at least one of claims 8 to 12,
    characterized in that
    the wiring carrier (800) can be mounted on the upper side of a housing (112), wherein a spark gap arrangement can be provided in the housing (112).
14. Spark gap arrangement according to claim 13,
    characterized in that
    the spark gap arrangement is connected in series and one or both spark gaps of the arrangement is/are triggerable and the trigger circuit(s) is/are located on the wiring carrier (800).
15. Spark gap arrangement according to one of claims 8 to 14,
    characterized in that
    the spark gap housing (112) has a depression-like recess (114) on its upper side, into which the first part of the series interconnection immerses so as to cause a protective and insulating function.

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