EP2070168A1

EP2070168A1 - Surge arrester having a housing and having at least one arrester element

Info

Publication number: EP2070168A1
Application number: EP08831283A
Authority: EP
Inventors: Jens Ehrler; Arnd Ehrhardt; Stefanie Schreiter
Original assignee: Dehn and Soehne GmbH and Co KG
Current assignee: Dehn SE and Co KG
Priority date: 2007-10-30
Filing date: 2008-10-29
Publication date: 2009-06-17
Anticipated expiration: 2028-10-29
Also published as: WO2009056565A1; DE102007051854B4; ATE476004T1; RU2474937C2; DE502008001020D1; DE102007051854A1; PL2070168T3; RU2010120019A; CN101842947B; CN101842947A; EP2070168B1

Abstract

The invention relates to a surge arrester having a housing (10) and at least one arrester element, such as a varistor, and a disconnection device, in order to disconnect the arrester element or elements from the mains, said disconnection device comprising a junction (14), which is incorporated in the electrical terminal path (A; B) inside the arrester, a movable conductor section or a movable conductive bridge (3) being connected via the junction (14) to the arrester element on the one hand and the conductor section or the bridge on the other hand, using a first electrical outer terminal of the arrester, and comprising a means which generates a pre-load force, such as a spring (6; 11), the force vector in this regard acting indirectly or directly via a movable disconnection bracket (13) on said conductor section or said bridge in the disconnection direction. According to the invention, a conductive element (4; 7) is disposed in the movement path of the conductor section or the bridge (3), the first end of the conductive element coming into contact with the conductor section or the bridge (3) if the disconnection device is triggered, the second end of the element being connected to a second electrical outer terminal, and said conductive element comprising a switching unit or being implemented as a switching unit.

Description

Surge arrester with a housing and at least one

diverter

description

The invention relates to a surge arrester having a housing and at least one diverting element, for example a varistor, and a disconnecting device for disconnecting the diverter element (s) from the mains, the divider device comprising a soldering point which is integrated into the electrical connection path inside the diverter, via the solder joint, a movable conductor section or a movable conductive bridge with the discharge element on the one hand and the conductor section or the bridge on the other hand connected to a first electrical external terminal of the arrester, and comprising a biasing force generating means, such as spring, wherein the relevant force vector directly or indirectly via a movable separating block acts on the conductor section or the bridge in the separating direction, according to the preamble of patent claim 1 as an addition to German Patent Application No. 10 2006 052 955.3.

Separating devices with short-circuit function, wherein in the separated or triggered switching state of the disconnecting device, the current path via the defective arrester element is in short circuit such that the current commutes from the diverter to a switched bypass, are known.

The low-impedance short circuit path connected in this way can be z. B. be used to actuate an upstream switching element, which is set to the short-circuit current of the relevant network, or to produce a defined continuous short circuit, which is defined in certain applications as a so-called fail-safe state.

Reference should be made, for example, to EP 0 860 927 A1 to this prior art. This publication describes a very complicated electromechanical device which monitors the current via a varistor and which, after exceeding a predetermined limit value, switches off the current Short circuit in the bypass to the varistor path switched via electromechanical contacts.

According to DE 37 34 214 C2 belongs to a thermally triggered separation device to the prior art, the switching element is a changeover contact. The changeover contact closes the varistor circuit in a known manner via a soldering point. If the switching element is triggered, another contact is closed, which can be connected either as an internal or external defect indicator or just via a corresponding external connection as a short circuit.

The prior art includes the arrangement for the derivation of surges, with several Ü berspannungsbegrenzende element such. B. varistors or diodes, and z. B. triggered by overheating or detection of the leakage current triggering means are provided according to DE 41 24 321 C2. In order to improve the safety of such an arrangement, in particular redundant form, there is provided that at least two overvoltage limiting elements are arranged, of which each element is sufficiently dimensioned for itself to ensure the overvoltage protection at the relevant site. A thermal shutdown in the sense of a thermal fuse monitors the leakage current of the surge limiting elements, so that z. B. a first element is switched off when overheating and a second element can be switched on.

An additional safeguard in the event that even after the failure of a first varistor switched redundant varistor fails, according to DE 41 24 321 C2 therein, the redundant varistor either by opening a switch in the cross-current path or by opening the switch in the longitudinal current path of the To disconnect tension. At the same time, the system to be protected is disconnected from the mains and protected against damaging overvoltages.

Alternatively, it should also be possible to bridge the cross-current path by short-circuiting an additional switch, so that ultimately the protected system is short-circuited. Opening this necessary shutter ters can be done synchronously via a joint operation. If disconnection and / or short-circuiting of the system to be protected is not desired, the function of the aforementioned switch can be canceled by employing bridging or removal of such means. In principle, however, the arrangement of additional switches for the short circuit in either the longitudinal or transverse current path is required, which further limits the expense of the already limited space of a surge arrester located in a housing.

Especially in photovoltaic systems due to the characteristic of the feeding source of the local operating current is approximately equal to the short-circuit current. A classic separation when heating a varistor and its separator is not effective in such DC applications, since the system voltage of photovoltaic systems is up to 1000 V and the interruption of 1000 V DC circuits can be realized only with a considerable constructive or equipment expense.

From the foregoing, it is therefore an object of the invention to provide a further developed surge arrester having a housing and at least one dissipation element, for example a varistor, as well as a disconnecting device, which is also retrofittable, able to safely conduct a short-circuit current, so that new fields of application result in for this purpose upgradeable or retrofittable arrester.

The object of the invention is achieved by a surge arrester according to combination of features of claim 1, wherein the dependent claims represent at least expedient refinements and developments.

In accordance with the invention, disconnecting devices for overvoltage arresters which are known per se are equipped with an additional connection which extends the existing disconnection function by a short-circuit function which leads to the fault current for a limited time. It is proposed that the additional connection different design, so that even when needed, an activation from the outside of the corresponding realized surge arrester is possible.

In the following description, it will be assumed with regard to the separating device that it comprises a solder joint with a solder which melts at the corresponding response temperature. Of course, the separating device can also be realized by other melting materials, which themselves have no conductive properties, namely, when the electrical connection to the connection path is made via a bridge part whose mechanical position is secured by means of the melting material.

According to the invention, at least one conductive element is arranged in the path of movement of the spring-biased conductor or the spring-biased bridge, the first end of which comes into contact with the conductor section or the bridge when the disconnecting device is triggered.

The second end of the conductive element is in communication with a second external electrical connection. Furthermore, means are provided for protecting the contact point between the conductor section or bridge and the conductive element before wegspratzenden Lotresten or solder material or the aforementioned melting materials.

In a preferred embodiment, the conductive element is designed as a bridge-like bracket whose second end is connectable to the external electrical connection when tightening a clamp provided for this purpose. In this way, the assembly is simplified because the bridge-like bracket does not need to be contacted separately.

In a further preferred embodiment, the first end of the conductive element has a quasi-flat or slightly curved plate shape, wherein the plate has a substantially parallel orientation to the conductor portion or to the bridge, with respect to the separation case. Due to this parallel orientation, the largest possible, low-ohmic contact and concerns should be realized.

The plate may have on its underside directed to the second end of a recess or a recess for receiving wegspratzendem solder or melting material. In this way, it is effectively prevented that solder deposits on the plate and forms raised areas there, with the consequence of an undesirable contact resistance. The recess is also able to absorb any eroded material of the conductor section or the bridge.

For the purposes of the invention, the conductive element can be subsequently inserted into the arrester in order to realize not only a disconnect but also a short-circuit fail-safe function.

The preferably provided bridge-like bracket as a conductive element has means for attachment to or in the arrester housing. The conductive element is dimensioned or designed so that after a predetermined time, the short-circuit function is canceled.

The means for attaching z. Example, a groove or a recess in the bracket and a complementary thereto nose or a counter-groove in the housing for producing a positive connection. Special modifications of such a fastener are of course the possible alternatives.

For selectively activating the conductive element in the sense of acting in the separation case short-circuiting a Isolierplättchen between the conductive element and the conductor portion or the bridge can be arranged. Alternatively, the conductive element may be provided, at least at its first end, with a releasable insulating coating, e.g. B. be provided in the form of an insulating tube. As well as the insulating plate and the insulating coating can be removed via a suitable opening in the housing to release the additional function "short circuit". For selectively activating the conductive member, in one embodiment of the invention, the relative distance between the conductive member and the conductor portion or the bridge can be adjusted. It is important to accomplish in a first position that the conductor section or bridge in the separation case comes into sufficient contact with the conductive element. On the other hand, it can be prevented by a Wegbegrenzung with respect to the conductor portion or the bridge, that the conductive element is touched. It is conceivable in this embodiment, the arrangement of a travel or stroke limiting, adjustable eccentric.

For selectively activating the conductive element in the sense of acting in the separation case short-circuiter can in a complementary embodiment in the path of movement of the conductor portion or the bridge, a limiting element z. B. in the form of a pin, bolt or the like stop.

As already stated, it is provided to make the insulating plate or the pin or bolt accessible from outside through the housing, in particular in order to be able to subsequently remove these means.

The respectively activated short-circuit function can be signaled via a display. It can also be provided to seal the access for removing the insulating plate, the pin or the pin. An example thinkable plug-like seal takes with the removal of the insulating plate or the pin or the bolt. Such a seal-free surge arrester indicates the intended additional short-circuit function.

The invention will be explained below with reference to an embodiment and with the aid of figures.

Hereby show: Fig. 1 is a schematic diagram of a trap with varistors and combined separation and short-circuiting properties;

Fig. 2 is a schematic representation of an embodiment of a separation device with switching function not triggered in the state;

Fig. 3 is a view similar to that of Figure 2, but in the state triggered and short circuit.

4 shows an embodiment of the switching device with removable insulating plate.

5a and 5b show a further embodiment of the switching device, wherein the short-circuit function is adjustable by eccentric controlled movement of the conductive element;

6 shows an exemplary embodiment of a surge arrester having a housing and a varistor discharge element as well as a thermal cut-off device, wherein a cut-off block transmits a mechanical movement to the thermal cut-off device and, in the event of disconnection, short-circuiting via a bridge-like hoop as a conductive element;

Figure 6b is a representation similar to that of Figure 6 but in the separated state and tripped short circuit.

Fig. 6a is a detail of the plate-shaped end of the bridge-like bracket with recognizable recess in the shorting position with respect to the tongue and

Fig. 7 is a schematic diagram with a conductive element as a switching device. As shown in FIG. 1, a varistor 2 is connected between the external terminals A and B. As shown in FIG. This varistor 2 can be cut off via a separating device (switching tongue) 3, which is thermally triggered. Between the points a and c there is usually an electrical connection via a conductor section or a bridge, in the non-triggered state. In state 3 ', the separating device 1 is triggered and it was a compound on the way a to b using a shorting bar 4 made, which bridges the varistor 2. The actuated or triggered short-circuit state is shown by dashed lines between the points a and b according to figure. With reference to FIG. 2 to 5, the switching movement is performed after the soldering of a solder under the influence of a compression spring 6 (reference numeral 11 of FIG. 6 and 6 b).

The Fig. FIG. 2 schematically shows the embodiment of a switching device 1 with a disconnecting and short-circuit function in the non-actuated or non-triggered state.

The actuated, d. H. triggered short-circuit state is shown in phantom in FIG. 2 in the illustration between the points a and b. As mentioned, the switching movement takes place after the Auslötvorgang under the influence of the force of the spring 6. The tongue 3, which forms the conductor portion is thus used simultaneously to realize the desired short circuit between the connection points A and B by these in abutment with the conductive Element or the shorting bar 4 passes.

With the help of Fig. 3, the actuated state, i. H. the desired short circuit between the points A and B, clearly, due to the movement of the switching tongue, which is now in the short-circuit layer 3 '.

In the embodiment according to FIG. 4, an insulating plate 7 is arranged so that the switching tongue 3 or 3 'can not get into contact with the shorting bar 4. This means that the movement path of the switching tongue 3, 3 'is limited by the insulating plate 7. Instead of an insulating plate 7, a pin or a bolt can be used in accordance with the invention. find or it is possible to cover at least the dashed end of the shorting bar 4 with a removable insulating tube.

According to the representations according to FIGS. 5 a and 5 b, in the case of the switching device 1, its short-circuit function can be switched on or off via manual actuation of a means, in particular of an eccentric 8.

With the aid of the eccentric 8, which allows different operating distances 8 ', 8 ", a movable part 4' of the shorting bar with respect to the rigid bracket part 4" can be changed, so that, as shown in FIG. 5b, it is possible to make contact with the switching tongue 3, which is not possible in the position of the movable part of the shorting bar 4 'according to FIG. 5a. For the purpose of limiting the movement of the switching tongue, a stop 9 is provided in this embodiment.

The eccentric 8 can easily via an opening in the housing shown in dashed lines in its various positions as shown in FIG. 5a and 5b are adjusted, and it is also clear by the recognizable free operating end of the eccentric 8, which respective state (short circuit or not) is present.

In the switch position disconnect according to FIG. 5a, a shorting bar 4 'mounted above the pivot point 5 is therefore located outside the operating radius and the effective range of the switching tongue 3, so that contact via the path a / b is prevented.

In contrast, in the "short-circuiting" position, the displacement of the movable short-circuiting bar 4 ', which is produced via the eccentric disk 8, makes it possible to connect via the path a / b into the action region of the switching tongue 3.

In the embodiment of FIG. 6, a surge arrester with an additional short-circuit function is integrated in a housing 10. With help of a pivotally mounted Abtrennbocks 13 and the tension spring 11 acts a bias on the switching tab 3, which is connected by means of a solder 14 with a guided through the housing partition 15 terminal 16 of a (not shown) varistor.

The conductive element is formed according to the embodiment of FIG. 6 as a bridge-like bracket 17. This bridge-like bracket 17 has a first end in plate form 18. A second end of the bridge-like bracket 17 is connected to an external electrical connection when tightening a clamp provided for this purpose 19 in connection.

The plate-shaped end 18 of the bridge-like bracket 17 has on its underside directed to the second end a recess 20 for receiving in the separation case possibly wegspratzendem solder from the soldering point 14.

The bridge-like bracket 17 can be fixed via means for fastening 21 on or in the arrester housing 10. The distance between the plate-shaped end 18 of the conductive member and the conductor portion 3 can be adjusted or changed by inclining or bending the plate-shaped end 18. Decisive is the angular position of the plate-shaped end 18 with respect to the position of the switching tongue 3. In any case, here is to ensure that for the desired safe short circuit, the switching tab 3 over a large area and just with the plate-shaped end 18 comes into contact.

If, as shown in FIG. 6, the switching tongue soldered via the soldering point 14 at the position c, there is a rotary movement of the Abtrennbocks 13 and thus a switching movement of the tongue 3 to the end position according to position b, which corresponds to the shorting position.

From the illustration of FIG. 6, it can be seen that the advanced surge arrester with short circuit function can be readily accommodated in a standard DIN rail mount housing, with the FIG bridge-like bracket 17 is easily accessible after removal of the housing cover, not shown. As a result, a surge arrester can be provided on the assembly side without, but also with a short-circuit function, with little effort, whereby a later short-circuit function can also be realized by subsequent insertion of the bridge-like yoke 17.

FIG. 6b shows an illustration of the separating device according to the invention in a realized device, namely in the tripped state (switch position triggered b).

The recess 20 in the region of the plate-shaped end 18 of the bridge-like bracket 17 is such that the soldering point 14 of the tongue 3 does not come into contact with the bridge-like bracket 17. Possibly adhering or splashing solder may pass through the clearance provided by the recess 20 and does not result in a possibly excessive contact resistance.

It is therefore the solder paste provided with the solder point 14 and 14 '(see Figure 6a) is not involved in the actual large-scale contact. Only the part b of the switching tongue 3 'abuts on the surface of the plate-shaped end 18 of the bridge-like bracket 17.

FIG. 7 shows a schematic representation with a conductive element which is designed as a switching device SE.

In the event of a permanent short circuit of the surge arrester, eg. As a MOV problems with transformerless inverters in photovoltaic systems can occur and that due to the resulting backflow.

In addition, when replacing a short-circuited surge arrester there is a risk of arc formation, since the arrester is short-circuited and current continues to flow from the photovoltaic generator. Here the maintenance staff can not tension measure because of the short circuit. In the subsequent attempt to replace the arrester creates a dangerous arc.

To avoid these disadvantages mentioned above, it is proposed in a refinement and development of the invention to combine the conductive element with a switching device or to form this conductive element itself as a switching device in the short-circuit branch.

The bypass formed by the switching device in the event of a short circuit is not designed here for continuous current carrying capacity. After the fault current has flowed over a certain time, the bypass is switched off. Due to the desired undersizing, the conductive element can have smaller cross sections of the electrically conductive parts and can therefore be manufactured more cost-effectively.

Thus, the conductive element may be formed as a fuse or else have a power semiconductor or form a circuit with a power semiconductor, wherein the power semiconductor is transferred after passing a short-circuit current by means of an initial pulse in the open state.

The functions assigned to the conductive element are shown with the symbolic representations of a semiconductor switch or a fuse in the figure 7, right side.

The sequence of functions can be represented as follows. In state (D the surge arrester is in proper function.

In case of overload of the surge absorber MOV, the connection of the thermal separator moves to position 0, d. H. to the connection point for the short-circuit element in the bypass. The short-circuit element SE is closed. The resulting during the opening of the thermal separation device arc is guided by the contact elements and extinguished independently when reaching the short-circuit contact. Immediately after chen of the short-circuit contact, the arc disappears and the current flows through the bypass, ie via the switching device SE.

After a predetermined time, the switching device SE opens and it is interrupted, the fault current.

As switching devices mechanical switching devices, fuses but also power semiconductors can be applied. Even spark gaps, which are designed for use in DC voltage circuits, can be used. The switching device according to the invention can be integrated in the surge arrester, but also the combination with an external switching device is possible. After the shutdown process, the defective overvoltage protection device is disconnected from the circuit, but the power supply is maintained. To initiate the opening operation of the switching device SE after a defined time, the switching device z. B. are formed by a cross-section reduction quasi as a fuse.

LIST OF REFERENCE NUMBERS

1 separating device with the contacts a, b and c

2 varistor

3 switching tongue (unactuated position) 3 'switching tongue (operated position)

4 shorting bars

4 'moving part of the shorting bar

4 "rigid part of the shorting bar

5 pivot

6 spring

7 insulating plate

8 eccentrics

8 'short operating distance of the eccentric

8 "long operating distance of the eccentric

9 stop

10 arrester housing

11 tension spring

13 detachment block

A first outer connection

B second external connection a varistor contact / connection to switching tongue b switch position ... triggered c switch position not tripped b 'second varistor contact

14 plumb point

15 partition wall

16 varistor connection at the soldering point

17 bridge-like hanger

18 plate-shaped end

19 clamp

20 recess

21 Means of attachment SE switching device

Claims

claims

An overvoltage arrester having a housing (10) and at least one diverting element, for example a varistor, and a disconnecting device for separating the diverter element (s) from the mains, the divider device comprising a soldering point (14) which is inserted into the electrical connection path (A; B) is integrated within the arrester, wherein via the solder joint (14), a movable conductor section or a movable conductive bridge (3) with the Ableitelement on the one hand and the conductor section or the bridge on the other hand connected to a first external electrical connection of the arrester, and comprising a Biasing force generating means, for example a spring (6; 11), wherein the relevant force vector acts indirectly or directly via a movable separating block (13) on the conductor portion or the bridge (3) in the separation direction, characterized in that in the path of movement of the conductor portion or the Bridge (3) a conductive element (4; 17) is arranged, the first end comes in triggered disconnector with the conductor portion or the bridge (3) into contact, wherein the second end is in communication with a second external electrical connection and the conductive element comprises a switching device or is formed as a switching device.

2. surge arrester according to claim 1, characterized in that the conductive element is a bridge-like bracket (17), the second end of the external electrical connection when tightening a clamp provided for this purpose (19) is connectable.

A surge absorber according to claim 1 or 2, characterized in that the first end of the conductive element (4; 17) has a plate shape (18), the plate having a parallel orientation to the conductor portion or bridge (3) in relation to the separation case ,

4. surge arrester according to claim 3, characterized in that the plate or the plate-shaped end (18) at its to the second end of the bridge-like bracket (17) directed bottom has a recess (20) for receiving wegspratzendem Lot.

5. surge arrester according to one of claims 1 to 4, characterized in that the conductive element (4; 17) is subsequently inserted into the arrester, in addition to a separation and a short-circuit fail-safe function to realize.

6. surge arrester according to one of claims 2 to 5, characterized in that the bridge-like bracket (17) has means for fastening (21) on or in the arrester housing (10).

7. surge arrester according to claim 6, characterized in that the means (21) comprise a groove or recess in the bracket (17) and a complementary thereto nose or counter-groove in the housing (10) for producing a positive connection.

8. Überspannungsabieiter according to any one of the preceding claims, characterized in that for selectively activating the conductive element (4; 17) in the sense of acting in separation shortcircuit an insulating plate (7) between the conductive element (4; 17) and the conductor portion or Bridge 3) or the conductive element (4; 17) has a detachable insulating coating at least on its first end.

9. surge arrester according to one of claims 1 to 7, characterized in that for selectively activating the conductive element in the sense of acting in a disconnect short-circuiting the relative distance between the leitfä- adjustable element (4; 17) and the conductor section or the bridge (3) is adjustable.

10. surge arrester according to one of claims 1 to 7, characterized in that for selectively activating the conductive element (4; 17) in the sense of acting in separation shortcircuit a movement of the conductor portion or the bridge (3) limiting element as a pin, bolt or the like arrangement can be used.

11. surge arrester according to claim 8 or 10, characterized in that the insulating plate (7) or the pin or bolt from the outside through the housing (10) is removable therethrough.

12. surge arrester according to claim 9, characterized in that the relative distance by an externally accessible through the housing (10) through the eccentric (8) by means of a tool or manually by hand is adjustable.

13. surge arrester according to one of the preceding claims, characterized in that the respective possible short-circuit function can be signaled by a display.

14. surge arrester according to one of the preceding claims, characterized in that the conductor section or the bridge (3) consists of a non-flexible material.

15. surge arrester according to claim 3, characterized in that the distance between the plate or the plate-shaped end (18) of the conductive element (4; 17) and the conductor section or bridge (3) is preferably changeable or adjustable by bending or bending the first end.

16. surge arrester according to one of the preceding claims, characterized in that the conductive element is designed as a fuse.

17. surge arrester according to one of claims 1 to 15, characterized in that the conductive element has a power semiconductor or forms a circuit with a power semiconductor, wherein the power semiconductor is transferred after passing a short-circuit current by means of an initial pulse in the open state.

18. surge arrester according to one of claims 1 to 16, characterized in that the conductive element is dimensioned in cross-section such that after passing a short-circuit current, a separation of the conductive connection takes place.

19. surge arrester according to one of claims 1 to 16 or 18, characterized in that the conductive element is not formed short-circuit continuous current carrying capacity.

20. surge arrester having a housing (10) and at least one diverting element, for example a varistor, as well as a separating device for separating the diverter element or elements from the network, the divider device comprising a soldering point (14) which is inserted in the electrical connection path (A; B) is integrated within the arrester, wherein via the solder joint (14), a movable conductor section or a movable conductive bridge (3) with the Ableitelement on the one hand and the conductor section or the bridge on the other hand connected to a first external electrical connection of the arrester, and comprising a Biasing force generating means, For example, a spring (6, 11), wherein the relevant force vector acts indirectly or directly via a movable separating block (13) on the conductor section or the bridge (3) in the separation direction, characterized in that

a conductive element (4, 17) can be arranged in the path of movement of the conductor section or the bridge (3), the first end of which comes into contact with the conductor section or the bridge (3) when the disconnecting device is triggered, the second end of which is in contact with a second external electrical connection Furthermore, means for protecting the contact point between the conductor section or bridge (3) and the conductive element (4; 17) are provided in front of erasing Lotresten,

- For selectively activating the conductive element (4; 17) in the sense of acting in separation shortcircuit an insulating plate (7) between the conductive element (4; 17) and the conductor portion or the bridge 3) can be arranged or the conductive element (4; 17) has a detachable insulating coating at least on its first end, or

- For selectively activating the conductive element in the sense of acting in the separation case short-circuiter, the relative distance between the conductive element (4; 17) and the conductor section or the bridge (3) is adjustable, or

- For selectively activating the conductive element (4; 17) in the sense of acting in separation shortcircuit a movement path of the conductor portion or the bridge (3) limiting element as a pin, bolt or the like arrangement is used, the short-circuiting canceled after a predetermined period of time is.

21. surge arrester according to one of the preceding claims, characterized by its use in DC voltage systems with high system voltages and operating currents at short-circuit current level, in particular for photovoltaic systems.