EP2532015B1 - Surge arrestor - Google Patents

Description

TECHNICAL AREA

The invention relates to the field of surge arresters according to the preamble of claim 1. Furthermore, the invention relates to a modular arrester system as well as a method for producing the surge arrester.

STATE OF THE ART

Surge arresters are known in various embodiments. For example disclosed EP-A-0 642 141 a surge arrester. This known surge arrester has an active part for dissipating overvoltage, which consists in particular of Varistorblöcken. The active part or the varistor blocks are used in a prefabricated frame made of glass fiber reinforced polyamide. The known frame has laterally frame openings through which the insertion of the diverting elements takes place in the frame. After inserting the electrodes and the varistor blocks in the frame, the varistor blocks and the electrodes are firmly clamped by means of a highly electrically conductive clamping device within the frame, whereby on the one hand the Varistorblöcke or the active part is held firmly in the frame and on the other a necessary contact pressure for contacting the varistor blocks are constructed with one another and / or for contacting the varistor block by means of one of the electrodes. The tensioning device, which typically has a threaded stud guided in a screw, forms EP-A-0 642 141 at the same time in each case a connection electrode or a connecting sleeve or parts thereof for the surge arrester. In other words , the electrode for contacting the varistor block relative to the frame is displaceable such that by turning the threaded pin, the initially spaced from the varistor block electrode can be brought into contact with the varistor and pressurized. The frame with the varistor blocks inserted therein is completely enveloped by a jacket with shields. The coat with the umbrellas is also called weatherproof housing.

In this known surge arrester proves to be disadvantageous that a gap is formed between the frame and the varistor. This gap is ideally filled by a silicone compound of the weatherproof housing. Due to the thermal stress during operation of the surge arrester and the permeability of silicone for water vapor can accumulate especially in this gap water. Such accumulations of water favor a failure of the high voltage arrester.

Another surge arrester is from the EP-A-0 614 198 known. In this surge arrester, the diverting elements are arranged between connection fittings, which in turn are connected by means of loops. By means of a rotatable, held in one of the connection fitting pressure screw, a contact electrode for contacting the varistor and the Varistorblocks is braced against each other. This also builds up the necessary contact pressure between the varistor blocks with each other and between the contact electrodes and the varistor blocks applied thereto. Each of the loops is made of wound glass fiber reinforced tapes embedded in a plastic matrix. The diverting elements and the loops are complete and the connection fittings are at least partially enclosed by a shielded cast housing made of insulating material, which forms a weatherproof housing.

Out EP-A-0 847 062 a further surge arrester is known. In this surge arrester, the clamping device is formed by an insulating tube into which one of the fittings is screwed end. Between the valves, in turn, a discharge element is arranged. By screwing the valve into the insulating tube, the fittings, the insulating tube and the diverter are firmly braced against each other. Further, this document shows that the insulating tube is preferably made of a thermoplastic polymer and a filler incorporated therein, such as glass fibers.

In another disclosed in E PA-0 847 062 embodiment of the surge arrester the insulating tube is the end with lids of insulating material after mounting the diverter and the fittings in Insulating tube closed. Preferably, the same insulating material is used for the lid and the closure is preferably done by means of ultrasound.

Out EP-A-0 372 106 a surge arrester is known in which the diverting elements, heat absorbing elements and connection fittings are inserted into a prefabricated tube made of polyethylene. After insertion of the diverting elements, heat-absorbing elements and connection fittings, the tube is shrunk in such a way that the diverting elements, heat-absorbing elements and connection fittings are pressed firmly against one another.

Out EP-A-0 393 854 a surge arrester is known which, in order to prevent a bursting in case of failure, has gas outlet openings.

Further surge arresters are off WO 97/32382 known. A first off WO 97/32382 known surge arrester has reinforcing strips for reinforcement in the axial direction of the surge arrester, which are embedded in a plastic matrix.

A second, also in WO 97/32382 disclosed surge arrester has a made of an insulating compound member which holds electrodes and varistor blocks together. The connecting element has a base layer of a resin material. Furthermore, the connecting element on one or more outer layers, which are also made of resin material. In the resin material of the outer layers, relatively short fiber bundles are mixed.

Surge arresters which may be used in medium and high voltage networks must comply, inter alia, with the IEC 60099 standard. In the case of surge arresters, there is the problem that under overuse of the diverting element, that is, if the active part with the varistor has absorbed too great an energy due to too high a temporary overvoltage or too high a line discharge, gas formation can occur within the active part. If the gas can not escape from the surge arrester, this leads to an explosion of the surge arrester. This poses a risk to the system itself, in which the surge arrester is arranged, as well as to persons who are employed in the immediate vicinity of the surge arrester.

PRESENTATION OF THE INVENTION

The object of the invention is to provide a trap which is inexpensive manufacturable, reliable in operation and meets the relevant safety standards.

According to the invention, this object is achieved by a surge arrester having the features of claim 1, by a modular arrester system having the features of claim 20 and by a method for producing a surge arrester according to claims 21 and 22.

The surge arrester according to the invention has an active part and two electrodes resting against the active part and a connecting element made of an insulating material, in which the active part and the electrodes are arranged. According to the invention, the connecting element disappears during its production. The shrinkage of the connecting element during cooling and / or curing, the electrodes are pressed firmly against the active part, whereby a good electrical contact between the respective electrode and the active part is made. Further, it can be ensured by the shrinkage, that the connecting element is applied directly to the active part, which can penetrate between the connecting element and active part no impurities such as water during operation of the surge arrester. This increases the reliability of the surge arrester. Furthermore, it proves to be advantageous that the connecting element bears radially directly on the active part, whereby the mechanical properties of the surge arrester are improved over the prior art, in particular with respect to shear forces. Next, the small number of items allows a very cost-effective production.

Further, the design of the connecting element can be optimized for strength, since after its production, no further elements are to be introduced into the connecting element, as is partially the case in the prior art, see, for example EP-A-0 642 141 , Consequently, the mechanical strength of the connecting element can be optimized and the cost of materials for the connecting element can be minimized. Consequently, costs can be reduced while complying with the relevant safety requirements and standards. Furthermore, the surge arrester according to the invention is easier to manufacture, since no special clamping elements such as screws and setscrews - as known in the art - are necessary for the production of the contact pressure between the electrodes and the active part.

Further, the connector is formed by direct potting around the electrodes and the active part. As a result, a particularly cost-effective production process can be realized. Further, the direct potting allows the connecting element to be directly adjacent, without gaps, around the active part. This means that no cavities occur in particular in the radial direction between the active part and the connecting element. As a result , the surge arrester has particularly favorable electrical properties, in particular, as a result no moisture or water can accumulate between the active part and the connecting element during the operating period of the surge arrester.

According to one embodiment according to claim 2, the connecting element has a homogeneous structure and a homogeneous material structure. This construction of the connecting element allows its complete production by means of an injection molding process. Consequently, the surge arrester according to claim 2 can be manufactured extremely cost-effectively, since this can be manufactured largely fully automatically.

According to one embodiment according to claim 3, the surge arrester has no reinforcement connecting the electrodes to one another. The insertion of a reinforcement would force a further production step before the injection or introduction of the material into the mold for the production of the connecting element. This additional manufacturing step is extremely bad - if anything - automatable. Consequently, as a result of the omission of reinforcements, the surge arrester can be manufactured substantially more cost-effectively than in the prior art.

According to an embodiment according to claim 4, the connecting element surrounds the active part and the electrodes both radially and axially with respect to the axis. By the axial enclosing are the electrodes positively held within the connecting element. As a result, in particular an axial ejection of the electrodes is prevented in the event of a fault.

Further preferred embodiments of the invention are specified in the dependent claims and in the exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

in Schnittdarstellung einen Überspannungsableiter gemäss einem ersten Ausführungsbeispiel mit Elektroden, welche steckbar sind;

FIG.2

den Überspannungsableiter gemäss FIG. 1 in perspektivischer Ansicht

FIG. 3

in Schnittdarstellung einen Überspannungsableiter gemäss einem zweiten Ausführungsbeispiel mit Elektroden, welche steckbar sind;

FIG.4

den Überspannungsableiter gemäss FIG. 3 in perspektivischer Ansicht;

FIG. 5 und 6

in Schnittdarstellung weitere Ausführungsbeispiele von Überspannungsableiter mit Elektroden, welche schraubbar sind;

FIG. 7 und 8

in Schnittdarstellung weitere Ausführungsbeispiele von Überspannungsableiter mit Elektroden, welche schweissbar sind;

FIG. 9

in Schnittdarstellung ein erstes Ausführungsbeispiel eines modular aufgebauten Ableitersystems, welches aus Überspannungsableitern gemäss FIG. 1 und 2 aufgebaut ist; und

FIG. 10

in Schnittdarstellung ein zweites Ausführungsbeispiel eines modular aufgebauten Ableitersystems, welches aus Überspannungsableitern gemäss FIG. 3 und 4 aufgebaut ist.

Hereinafter, an embodiment of the invention will be explained in detail with reference to drawings. This shows purely schematically

FIG. 1

in a sectional view of a surge arrester according to a first embodiment with electrodes, which are pluggable;

FIG.2

the surge arrester according to FIG. 1 in perspective view

FIG. 3

in a sectional view of a surge arrester according to a second embodiment with electrodes, which are pluggable;

FIG.4

the surge arrester according to FIG. 3 in perspective view;

FIG. 5 and 6

in sectional representation of further embodiments of surge arrester with electrodes which are screwed;

FIG. 7 and 8

in sectional representation of further embodiments of surge arrester with electrodes which are weldable;

FIG. 9

in a sectional view of a first embodiment of a modular arrester system, which consists of surge arresters according to FIG. 1 and 2 is constructed; and

FIG. 10

in a sectional view of a second embodiment of a modular arrester system, which consists of surge arresters according to FIG. 3 and 4 is constructed.

The reference numerals used in the drawings and their meaning are listed in the list of reference numerals. Basically, the same parts are provided with the same reference numerals in the figures . The described embodiments are exemplary of the subject invention and have no limiting effect.

WAY FOR CARRYING OUT THE INVENTION

FIG. 1 shows a surge arrester according to the invention 10. The surge arrester 10 essentially comprises the following elements: an active part 12, two electrodes 14, 16 and a the active part 12 and the electrodes 14, 16 interconnecting, made of an insulating material connecting element 18th

The active part 12 has at least one with respect to the current-voltage ratio nonlinear resistance, in particular a non-linear resistor based on zinc oxide (ZnO). Such non-linear resistors are also referred to as varistors. The active part 12 has substantially the shape of a straight circular cylinder with axis A, wherein each of the two end faces of the circular cylinder as a contact surface 13 for electrically contacting the active part 12 by means of one of the two electrodes 14, 16 is formed. Other forms for the active part 12 are in principle also possible, in particular a hollow cylindrical shape. The axis A of the circular cylinder or the active part 12 lies on an axis A of the surge arrester 10.

The surge arrester 10 according to the invention fulfills the IEC 60099 standard. In particular, the surge arrester 10 has at least a nominal voltage of 1 kV (one kilovolt). Consequently blocks the active part 12, if a voltage lower than the nominal voltage applied to the active part 12. At a voltage which is greater than the rated voltage, the active part 12 is conductive. Consequently, voltages which are greater than the rated voltage, which are also referred to as overvoltages, are derived by the surge arrester 10.

In the direction of the axis A is on one side of the active part 12, the first electrode 14 of the two electrodes 14, 16 to the active part 12 at. At the first electrode 14 opposite side of the active part 12, the second electrode 16 is located on the Discharge element 12 at. Consequently, in the direction of the axis A on one side of the active part 12, the first electrode and on the other side, the second electrode 16 is arranged, wherein the second electrode 16 in the direction of the axis A with respect to the active part 12 of the first electrode 14 opposite. In an alternative embodiment, the electrodes 14, 16 are additionally attached to the active part 12 with an electrically conductive adhesive.

The two electrodes 14, 16 - the first electrode 14 and the second electrode 16 - each have a contact surface, which is intended to abut the respective contact surface 13 of the active part 12. Next, the two electrodes 14, 16 each have a connecting and contacting region 17.

Around the active part 12 and the two electrodes 14, 16 around the connecting element 18 is formed. The connecting element 18 is injected, for example, in an injection molding process around the active part 12 and around the two electrodes 14, 16. This method is an example of a direct potting. Consequently, the connecting element 18 encloses the active part 12 and the two electrodes 14, 16. In particular, the connecting element 18 bears radially with respect to the axis A directly to the active part 12. Due to the fact that the connecting element 18 contracts on shrinkage and / or hardening in the direction of the axis A by shrinkage, each of the two electrodes 14, 16 with respect to the active part 12 is subjected to a pressure, so that between each of the two electrodes 14, 16 and Active part 12 a good electrical connection is made. Consequently, thanks to the production of the connecting element 18 by encapsulation of the active part 12 and the two electrodes 14, 16, an internal stress in the connecting element 18 can be constructed, which clamps the electrodes 14, 16 and the active part 12 against each other. Consequently, the connecting element 18 presses the two electrodes 14, 16 in the direction of the axis A to the active part, wherein the voltage in the connecting element 18 for pressing the electrodes 14,16 to the active part 12 is established by the manufacturing process.

Thanks to the production of the connecting element 18 by encapsulation of the active part and the two electrodes 14, 16, consequently, in contrast to the prior art to a separate element or device for building up the mechanical tension for clamping the active part 12 with the electrodes 14, 16 be waived. Next can be dispensed with a special, necessary to build up this voltage step. In other words, the first electrode 14 as well as the second electrode 16 with respect to the connecting element 18 is arranged stationary.

By the production of the connecting element 18 by injection molding and by the production of the connecting element 18 by encapsulation of the active part 12 and the two electrodes 14, 16, it is possible to form the connecting element 18 with particularly favorable mechanical properties at low cost of materials. Further, thanks to the extremely simple structure of the surge arrester 10 made of active part 12, electrodes 14, 16 and connecting element 18, the manufacturing process can be largely automated, whereby the reduction in manufacturing costs can be achieved. The automation of the manufacturing process is made possible in particular by the fact that a separate element or device for building up the voltage for clamping the active part 12 with the electrodes 14, 16 is dispensed with. Next can be dispensed with a special step for building up the voltage, since the mechanical tension of active part 12 and the two electrodes 14, 16 takes place by the cooling and / or curing of the connecting element 18.

The connecting element 18 has passage openings 30 in a region adjacent to a jacket region of the active part 12, that is to say in the direction of the axis A between the two electrodes 14, 16. These through-holes 30 serve to dissipate a gas which forms at most in the event of a fault of the active part 12 in the interior of the connecting element, without the connecting element 18 being destroyed in an explosive manner. Through the passage openings 30 in particular an explosive destruction of the surge arrester 10 is prevented in the event of a fault.

The through holes 30 are formed in forming the connecting member 18.

Consequently, through the through-openings 30 gas outlet openings are formed, through which gas, which can form within the connecting element in the event of a fault, can flow out. Due to the formation of the passage openings 30 in Area of the connecting element 18, which adjoins the jacket region of the active part 12, can consequently flow outward radially with respect to the axis A, which at most forms in the region of the active part 12.

In one embodiment, the connecting element 18 has at least two and / or at most twenty through openings 30. The connecting element 18 preferably has at least three and at most ten passage openings 30, particularly preferably at least three and at most five passage openings 30.

The clear cross-sectional areas of the passage openings 30 are at least substantially equal to each other. Further, the through holes 30 are formed at regular intervals in the circumferential direction with respect to the axis A to each other on the connecting element 18. As a result, the connecting element 18 has a cage-like structure. The manufacturing process makes it possible for the connecting element 18 with this structure to be produced in one piece or to be able to be manufactured in one piece.

The cage-like structure is characterized in particular in that the active part 12 can not escape through the passage openings 30. As a result, ejection of the active part 12 or parts or large fractions thereof out of the connecting element 18 can be prevented in an advantageous manner. The cage-like structure thus contributes directly to safety in the event of a fault. If the active part 12 is overloaded in the event of a fault due to excessive overvoltage, this can lead to gas formation and / or fragmentation of the active part 12. The resulting gases could cause fragments to be thrown off. The connecting element 18 of the inventive surge arrester 10 effectively prevents the throwing away of fragments.

The cage-like structure is further characterized in that the electrodes 14, 16 in the direction of the axis A as well as in the radial direction are positively held within the connecting element 18.

In other words, the connecting element 18 surrounds the active part 12 and the electrodes 14, 16 radially as well as axially with respect to the axis A.

As shown in the figures, the connecting element 18 completely surrounds the active part 12 and the electrodes 14, 16 except in the connection and contacting area 17 in the direction of the axis A. As stated, the connecting element 18 in the circumferential direction. Through openings 30.

Consequently, the cage-like structure prevents the electrodes 14, 16 from being thrown out of the connecting element 18 in the event of a fault, in particular in the direction of the axis A.

Preferably, in the direction of the axis A, only or at most the connecting and contacting region 17 of the respective electrode 14, 16 projects out of the connecting element 18.

If the connecting element 18 in particular has an even number of passage openings 30, the passage openings can also have different clear diameters, in which case attention must be paid to regular training in the circumferential direction. For example, can follow a passage opening with a larger clear diameter, a passage opening with a smaller clear diameter, wherein the passage opening with the smaller clear diameter again followed by a passage opening with the larger clear diameter. Other sequences, for example with three different clear diameters, are also conceivable. By choosing the number of through holes and by choosing the shape of the through holes, the mechanical stability of the connecting element 18 with respect to the mechanical tension of active part 12 and the two electrodes 14, 16 on the one hand and the mechanical requirements of the connecting element 18 can be optimized in case of failure. In the event of a fault, the mechanical requirements for the connecting element 18 are characterized in particular by the fact that at most gas has to escape from the interior of the connecting element 18, but no large fragments may be ejected from the interior of the connecting element 18.

A total area, that is to say the accumulated surface area of the passage openings 30, is between 20% and 90%, preferably between 30% and 80% and particularly preferably between 40% and 70% of the lateral surface of the active part 12. The lateral surface of the active part 12 is that part the surface of the Active part 12, which in the direction of the axis A between the two contact surfaces 13, to which each one of the two electrodes 14, 16 is located.

Alternatively, the total area of the through openings 30 can amount to at least 33% of the lateral surface of the active part 12.

The through openings 30 preferably have at least approximately an elliptical shape, with the longer of the two ellipse axes extending in the direction of the axis A. This ensures that the connecting element 18 has particularly good mechanical properties.

So that the connecting element 18 can be manufactured completely by means of injection molding, a material is used for the connecting element 18 which is suitable for injection molding. These are in particular homogeneous materials. Homogeneous materials also include macroscopically homogeneous mixtures of materials such as those set out below. Consequently, the connection element 18, which is produced entirely by injection molding, itself likewise has an at least macroscopically homogeneous structure and an at least macroscopically homogeneous material structure.

For example, the structure of the connecting element 18 does not have different and / or not multiple layers. Further, no reinforcements such as bands or the like are inserted or embedded in the connecting element, which connect the two electrodes together. Such reinforcements would lead to an inhomogeneous construction of the connecting element and make impossible the complete manufacture of the connecting element by means of injection molding, since the reinforcements must be inserted into the injection mold before injecting the material into the latter. Consequently, the electrodes 14, 16 in the fully injection molded connector 18 are solely interconnected therewith.

The connecting element 18 is preferably made of a thermoset material. This may contain as a filler inextensible fiber or balls. Furthermore, further additives may be contained in the connecting element 18. As fibers, glass fiber, basalt fibers and aramid fibers are conceivable. The fiber length must be suitable for the injection molding process or the pressure casting process.

Alternatively, the connecting element 18 can also be made of a plastic. In general, the material used for the connecting element 18 must in particular fulfill the condition that the material does not creep or almost does not creep, since otherwise the contact pressure between the electrodes 14, 16 and the active part 12 decreases over the operating time. Next, the material should network. In addition, the material must be electrically insulating. Again, fillers, additives and / or fibers can be added to the plastic as stated above.

The two electrodes 14, 16 are preferably made of a highly electrically conductive sheet, such as aluminum, steel, bronze or copper or their alloys and preferably have a sheet thickness of, for example, 0.1 mm to 6 mm, preferably from 0.5 mm to 4 mm and most special preferably from 1 mm to 3 mm.

Like in the FIG. 1 As shown, the connection and contacting region 17 of the two electrodes 14, 16 may be formed differently. The connection and contacting region 17 of the first electrode 14 of the two electrodes 14, 16 is intended to be connected to a connection fitting or, as described in connection with FIG Fig. 9 described to cooperate with the second electrode 16 of another surge arrester 10 'together. The surge arrester 10 and the further surge arrester 10 'are preferably formed largely the same, but may in particular have an active part 12 for different rated voltages. In order to cooperate with the second electrode 16 of the further surge arrester 10 ', the first electrode 14 has a pin extension 50, which is intended to cooperate with a mounting hole 52 of the second electrode 16. Characterized in that the surge arrester 10 on the one hand, the first electrode 14 with the pin extension 50 and on the other hand, the second electrode 16 with the mounting hole 52, several surge arresters 10 can be strung together, the pin extension 50 and the mounting hole 52 are matched to each other, that by Inserting the pin extension 50 in the mounting hole 52 a mechanically strong and electrically good conductive connection is made.

If the surge arrester 10 is provided with connection fittings, the connection and contacting region 17 of the first electrode 14 and / or the second electrode 16 also be designed differently. Furthermore, the connection and contacting region 17 of the first and / or the second electrode 14, 16 can also be designed as a connection fitting.

Further embodiments of the two electrodes 14, 16 are shown in FIG FIG. 5 to 8 shown, the FIG. 5 and 7 each shows an embodiment which is formed largely the same as the first, in FIG. 1 and 2 shown embodiment, but with differently shaped electrodes 14, 16. Die FIG. 6 and 8 each show an embodiment which is largely the same, as the second, in FIG. 3 and 4 shown embodiment, but with differently shaped electrodes 14, 16th

In the FIG. 5 and 6 shown electrodes 14, 16 are formed such that the electrodes 14, 16 are screwed together. For this purpose, the first electrode 14 has a screw thread arranged radially on the outside in the connection and contacting region 17. In the connection and contacting region 17, the second electrode 16 has a radially inner screw thread, which is intended to be screwed onto the screw thread of the first electrode 14 or onto a correspondingly identical screw thread.

In the FIG. 7 and 8 shown electrodes 14, 16 are formed such that the electrodes 14, 16 are welded together. The electrodes 14 16 may be the same in this case.

The in Fig. 1 and 2 shown arrester 10 is manufactured as follows.

The active part 12 and the two electrodes 14, 16 are placed in a mold, in particular injection mold, wherein the first electrode 14 and the second electrode 16 each abut with their contact surface on one of the two contact surfaces 13 of the active part 12. By means of one or two slides of the injection mold displaceable in the direction of the axis A of the active part 12, the first electrode 14 and the second electrode 16 are preferably pressed firmly against the active part 12. By means of further, with respect to the axis A radially displaceable radial slide, the shape is designed such that after spraying the connecting element 18, as in connection with the FIG. 1 and 2 described results. In particular, be the radial slide pressed radially to the active part 12. The radial slide serve to form the through holes 30 in the connecting element 18. Subsequently, the material for producing the connecting element 18 is injected into the mold. Upon cooling and / or curing of this material, this shrinks in particular in the direction of the axis A, whereby a voltage is built up in the connecting element 18, which presses the two electrodes 14, 16 firmly against the active part 12. This voltage ensures a sufficient contact pressure for electrically contacting the active part 12 by the two electrodes 14, 16 sure.

Alternatively to the production of the connecting element 18 by means of injection molding, the connecting element 18 can also be produced by a pressing process. In such a method, the material for producing the connecting element 18 is provided, for example, in the form of mats or the like. The material is inserted into a mold, in particular a press mold. The mold has recesses which correspond to the negative shape of the connecting element 18. After inserting the material, the active part 12 and the two electrodes 14, 16 are inserted into the mold. After inserting the material, the electrodes 14, 16 and the active part 12, the mold is closed. By heat and pressure, the connecting element 18 is made of the material, wherein the material hardens and shrinks analogous to the injection molding process. As a result, the electrodes 14, 16 are pressed against the active part analogously to the production method by means of injection molding. This pressing method is another example of a direct potting.

In further embodiments, the active part 12 next to the varistor further elements such as metal blocks have. Alternatively, the active part can also be formed only by one metal block or a plurality of metal blocks. Likewise, the active part 12 may comprise a plurality of varistors. Metal blocks can be used to dissipate heat from the varistor and / or to increase the creepage distance between the connection fittings of the surge arrester.

Furthermore, the varistor and / or the further elements can be enveloped or wrapped with a non-conductive material. A wrapping material may be, for example, a glass fiber, aramid fiber or basalt fiber. Instead of fibers, bands can also be used.

In FIG. 3 and 4 a second embodiment of the inventive surge arrester 10 is shown. The in FIG. 3 and 4 shown Surge arrester 10 is largely similar to that in connection with FIG. 1 and 2 described surge arrester 10 is formed. In addition, the surge arrester 10 according to the second embodiment has a housing or weatherproof housing 40.

The housing 40 is preferably made of silicone and encloses the connecting element 18 with the active part 12 in the circumferential direction completely. In the direction of the axis 10, the housing 40 extends over the full height of the surge arrester 10. The housing 40 has in the direction of the axis A in the region of the first electrode 14 and the second electrode 16 screens 42. In the area of the through openings 30, the housing 40 has a wall thickness which is chosen such that, in the event of a fault, gas can escape from the connecting element 18 through the through openings 30 at least almost unhindered. When the gas escapes, the housing or weatherproof housing 40 can be damaged, for example by tearing open the housing 40 in that area which abuts against the passage openings 30 of the connecting element 18, so that the gas can escape at least almost unhindered.

If the surge arrester 10 is designed for indoor applications, the housing 40 can also be manufactured without screens 42.

The housing 40 may have - except at most in the area of the screens 42 - an at least approximately uniform wall thickness of, for example, between 1 mm and 10 mm, preferably between 1 mm and 6 mm and more preferably between 2 mm and 3 mm. Consequently, the passage openings formed in the connecting element 18 are also distinguished from the housing 40. Due to the at least approximately uniform wall thickness - except at most in the area of the screens 42 - the problem-free gas outlet is made possible in the event of a fault.

The in FIG. 3 and 4 shown surge 10 is largely the same as that associated with Fig. 1 and 2 produced surge arrester produced. In a further process step, the housing 40 is sprayed around the connecting element 18 with the electrodes 14, 16 and the active part 12. Alternatively, the Housing also prefabricated and pushed onto the connecting element 18 with the electrodes 14, 16 and the active part 12.

In FIG. 9 and 10 In each case a modular arrester system 60 is shown. These arrester systems 60 are modular in connection with FIG. 1 and 8th described surge arrester 10 constructed. In order to fabricate the arrester system 60 in a modular design from surge arresters 10, prefabricated surge arresters 10, as in FIG. 1, 2 . 3, 4 . 5, 6, 7 or 8 shown lined up in the direction of the axis A and electrically and mechanically connected to each other via the electrodes 14, 16. The connection is preferably carried out in the region of the directly successive electrodes of two surge arresters 10 which are adjacent in the direction A, for example by pressing in the in FIG. 1-4 shown pin attachment 50 in the correspondingly shaped mounting hole 52 also in FIG. 1-4 Alternatively, for example, the in FIG. 5, 6 shown external thread 53 of the first electrode 14 in the also in FIG. 5, 6 shown internal thread 54 of the second electrode 16 are screwed. Another alternative is to weld the electrodes as in FIG. 7, 8 mentioned. Further variants for connecting the electrodes 14, 16 are well known to the person skilled in the art.

As in FIG. 10 As shown, the housing 40 may be disposed on each surge arrester 10. Alternatively, the in FIG. 10 two-piece housing 40 may also be integrally formed. In this case, the modular arrester system 60 is manufactured as follows. Multiple surge arresters as in 1 and 2 are connected to each other at the electrodes 14, 16 mechanically as well as electrically. Subsequently, the housing 40 is formed over the entire length in the direction of the axis A of the arrester system 60, for example by pushing a prefabricated housing 40th

The active part 12 used in the surge arresters 10 may be designed, for example, for a rated voltage of 4 kV (kilovolts) or 6 kV. As a result, the lead-off system 60 can be constructed with rated voltages in steps of 4 kV or 6 kV from the surge arresters 10. For example, can be by assembling a surge arrester 10 with a rated voltage of 4kV and a surge arrester 10 with a nominal voltage of 6 kV Conductor 60 realize a nominal voltage of 10 kV. Consequently, surge arresters 60 for nominal voltages of, for example, 8 kV, 10 kV, 12 kV, 14 kV, 16 kV, etc. can be realized from the surge arresters. Of course, the nominal voltages of the surge arresters are not limited to 4 kV and 6 kV, but other rated voltages can also be selected. Consequently, the arrester system 60 can be modularly constructed in arbitrary steps of, for example, 1 kV, 2 kV, 3 kV, or even 0.5 kV or 10 kV .

LIST OF REFERENCE NUMBERS

10, 10 '

Surge arresters

12

active part

13

contact surfaces

14

first electrode

16

second electrode

17

Connection and contacting area

18

connecting element

30

Through opening

40

Housing, weatherproof housing

42

umbrella

50

Post extension

52

mounting hole

53

external thread

54

inner thread

60

Ableitersystem

A

axis

Claims (25)

1. Surge arrester (10) having an active part (12), which has at least one diverting element, particularly a varistor, preferably based on ZnO, and at least a nominal voltage of 1 kV, the active part (12) being constructed cylindrically and extending along an axis (A), two electrodes (14, 16) resting against the active part (12) and being arranged opposite one another in the direction of the axis (A), and a connecting element (18), the connecting element (18) being manufactured of a non-creeping and electrically insulating plastic and pressing the electrodes (14, 16) firmly against the active part (12) for electrically contacting the active part (12) by means of the electrodes (14, 16), the connecting element (18) resting directly against the active part (12) at least radially with respect to the axis (A), and the connecting element (18) pressing the electrodes (14, 16) against the active part (12) in the direction of the axis (A) due to shrinkage in the direction of the axis (A) during the production of the connecting element (18), characterized in that the connecting element (18) has passage openings (30) in an area between the two electrodes (14, 16), and in that the connecting element (18) is constructed by means of direct casting around the electrodes (14, 16) and the active part (12).
2. Surge arrester according to Claim 1, characterized in that the connecting element (18) has an at least macroscopically homogenous structure and an at least macroscopically homogenous material structure.
3. Surge arrester according to Claim 1 or 2, characterized in that the surge arrester (10) has no reinforcement connecting the electrodes (14, 16) to one another.
4. Surge arrester according to one of Claims 1 to 3, characterized in that the connecting element (18) encloses the active part (12) and the electrodes (14, 16) radially and axially with respect to the axis (A).
5. Surge arrester according to one of Claims 1 to 4, characterized in that the surge arrester (10) has no further device for pressing the electrodes (14, 16) against the active part (12).
6. Surge arrester according to one of Claims 1 to 5, characterized in that the connecting element (18) is made in an injection molding method or die-casting method.
7. Surge arrester according to one of Claims 1 to 6, characterized in that the passage openings (30) are gas outlet openings through which gas which can form inside the connecting element (18) can flow off radially outwardly.
8. Surge arrester according to one of Claims 1 to 7, characterized in that the connecting element (18) has at least 2 and/or at most 20 passage openings (30) in the peripheral direction with respect to the axis (A), preferably between 3 and at most 10 passage openings (30) and especially preferably at least 3 and at most 5 passage openings (30).
9. Surge arrester according to one of Claims 1 to 8, characterized in that a total area of the passage openings (30) is between 20% and 90%, preferably between 30% and 80% and especially preferably between 40% and 70% of a jacket area of the active part (12).
10. Surge arrester according to one of Claims 1 to 9, characterized in that the passage openings (30) have at least approximately an elliptical shape, the longer one of the two axes of the ellipse extending in the direction of the axis (A) of the active part (12).
11. Surge arrester according to one of Claims 1 to 10, characterized in that the connecting element (18) is made of a plastic which contains a thermosetting plastic.
12. Surge arrester according to one of Claims 1 to 11, characterized in that the connecting element (18) is constructed to be produced integrally.
13. Surge arrester according to one of Claims 1 to 12, characterized in that the connecting element (18) encloses the active part (12) and the two electrodes (14, 16).
14. Surge arrester according to one of Claims 1 to 13, characterized in that the electrodes (14, 16) are made of electrically conductive sheet metal.
15. Surge arrester according to Claim 14, characterized in that the sheet metal has a thickness of 0.1 mm to 6 mm, preferably 0.5 mm to 4 mm and especially preferably from 1 mm to 3 mm.
16. Surge arrester according to one of Claims 1 to 15, characterized in that the electrodes (14, 16) are arranged to be stationary with respect to the connecting element (18).
17. Surge arrester according to one of Claims 1 to 16, characterized in that the electrodes (14, 16) are constructed as connecting fixtures or connecting electrodes.
18. Surge arrester according to one of Claims 1 to 17, characterized in that the connecting element (18) with the active part (12) arranged therein is enclosed by a housing (40), particularly a weather protection housing, at least in the peripheral direction with respect to the axis.
19. Surge arrester according to Claim 18, characterized in that the housing (40) has, except in the area of a shield (42) if at all, an at least approximately uniform wall thickness of, for example, between 1 mm and 10 mm, preferably between 1 mm and 6 mm and especially preferably between 2 mm and 3 mm.
20. Modularly constructed arrester system (60) constructed of at least two surge arresters (10, 10') according to one of Claims 1 to 19, wherein the first electrode (14) of one surge arrester (10) is connected electrically and mechanically to the second electrode (16) of the other surge arrester (10') of the at least two surge arresters (10, 10').
21. Method for producing an surge arrester (10) according to one of Claims 1 to 19, wherein the surge arrester (10) has an active part (12) which has at least one diverting element, especially a varistor based on ZnO, the active part (12) being constructed cylindrically, extending along an axis (A) and having two mutually spaced-apart contacting areas (13) in the direction of the axis (A), the method comprising the following steps:

    • inserting the active part (12) and two electrodes (14, 16) into a die, especially an injection molding die, the active part (12) and the electrodes (14, 16) being inserted in such a manner that a first electrode (14) of the two electrodes (14, 16) rests against one contacting area (13) and a second electrode (16) of the two electrodes (14, 16) rests against the other contacting area of the active part (12),

    • injecting a material forming a connecting element (18) around the active part (12) and the electrodes (14, 16), passage openings (30) being molded into the connecting element (18) during the sheathing, and

    • shrinking of the material for forming the connecting element (18) in the direction of the axis (A) during the cooling and/or curing in the die, as a result of which the electrodes (14, 16) are pressed against the active part (12),

    the material for forming the connecting element being a non-creeping and electrically insulating plastic.
22. Method for producing an surge arrester (10) according to one of Claims 1 to 19, wherein the surge arrester (10) has an active part (12) which has at least one diverting element, especially a varistor based on ZnO, the active part (12) being constructed cylindrically, extending along an axis (A) and having two mutually spaced-apart contacting areas (13) in the direction of the axis (A), the method comprising the following steps:

    • inserting a material into a die, particularly a compression die which is intended for forming a connecting element (18) for firmly pressing the electrodes (14, 16) against the active part (12) for electrically contacting the active part (12) by means of the electrodes (14, 16), and

    • inserting the active part (12) and two electrodes (14, 16) into the die, the active part (12) and the electrodes (14, 16) being inserted in such a manner that a first electrode (14) of the two electrodes (14, 16) rests against one contacting area (13) and a second electrode (16) of the two electrodes (14, 16) rests against the other contacting area of the active part (12),

    • pressing the active part (12), the electrodes (14, 16) and the material as a result of which the connecting element (18) is formed from the material, passage openings (30) being molded into the connecting element (18) during the pressing, and

    • shrinking of the material for forming the connecting element (18) in the direction of the axis (A) during the cooling and/or curing in the die, as a result of which the electrodes (14, 16) are pressed against the active part (12),

    the material for forming the connecting element being a non-creeping and electrically insulating plastic.
23. Method according to Claim 21 or 22, characterized by pressing elements of the die, forming passage openings (30) of the surge arrester (10), against the active part (12).
24. Method according to one of Claims 21 to 23, characterized in that the material for forming the connecting element is a thermosetting plastic.
25. Method according to one of Claims 21 to 24, characterized by pressing the two electrodes (14, 16) against the active part (12) by means of sliders constructed so as to be movable in the direction of the axis (A) after the insertion of the electrodes (14, 16) and of the active part (12) into the die.

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