RU2474937C2 - Discharger for protection against overvoltages with body and at least one discharge element - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to a discharger of protection against overvoltages with a body (10) and at least one discharge element, for instance, a varistor, and also a disconnecting accessory, serving to disconnect the discharge element or discharge elements from the grid. The disconnecting accessory includes a soldering area (14), which is a part of an electric path (A; B) of the connection within the discharger. Via the soldering area (14) a movable section of a conductor or a movable electroconductive link (3) is connected at one side with the discharge element, and at the other side - with the first electric outer lead of the discharger. The discharger also comprises a facility developing a pre-tensioning force, for instance, a spring (6; 11), besides, the appropriate vector of the force is directly or indirectly via a movable separating bracket (13) impacts the conductor area or the link (3) in direction of disconnection. On the way of movement of the conductor section or the link (3) there is a conducting element (4; 17), the first end of which with the actuated disconnecting accessory contacts with the section of the conductor or the link (3), besides, its second end is connected with the second external electric lead. The conducting element includes a switching device or its arranged in the form of a switching device.

EFFECT: higher reliability of conducting short-circuit current.

20 cl, 10 dwg

Description

Technical field

The invention relates to a surge arrester with a housing and at least one discharge element, for example, a varistor, and also to a disconnecting device (disconnector), which serves to disconnect the discharge element or discharge elements from the network, and the disconnector includes a place soldering, which is included in the electrical connection path within the spark gap, and through the soldering place, the movable section of the conductor or the movable conductive jumper is connected or connected on one side with by means of a spacer element, and on the other hand, with the first electrical external terminal of the spark gap, and also including means that create a pre-tensioning force, for example, a spring, the corresponding force vector acting indirectly or directly through the movable dividing bracket on the conductor section or on the jumper in the direction separation, according to the restrictive part of paragraph 1 of the claims as a supplement to the German patent application number 102006052955.3.

State of the art

Known circuit breakers, including those with a short circuit function, in which, when the disconnecting device is separated or tripped, the current path through the damaged element of the arrester is short-circuited so that the current from the discharge element is directed to the connected bypass.

The low-resistance short-circuit path included in this way can be used, for example, to drive a switching element connected in front of it, which is configured for the short-circuit current of the corresponding network, or to produce a specified long-term short-circuit, which for some applications is defined as called a fail-safe or fail-safe state.

This prior art relates, for example, patent document EP 0860927 A1. This publication describes a very expensive electromechanical device that monitors the current flowing through the varistor, and which, when the set limit value is exceeded, short-circuits the bypass to the varistor circuit by switching the electromechanical contacts.

According to patent document DE 3734214 C2, a disconnecting device which is thermally actuated, the switching element of which is a double-acting contact, relates to the prior art. A double-acting contact in a known manner closes the varistor circuit through the soldering point. When the switching element is activated, another contact closes, which allows you to reconnect it either as an internal or external indicator of damage, or, through the corresponding external connection, as a short circuit.

The prior art also relates to an overvoltage protection structure, in which there are several overvoltage limiting elements, such as varistors or diodes, and disconnecting means that are actuated, for example, by overheating or when a leakage current is detected, according to DE 4124321 C2. In order to improve the reliability of such a structure, in particular to create redundancy, it is provided that at least two surge-limiting elements are installed in it, each of which is sufficient to provide surge protection at the appropriate place of application. A thermal cut-off device such as a thermal fuse controls the leakage current of elements that limit overvoltage, so that, for example, the first element can be switched off during overheating, and the second element can be connected.

An additional reliability assurance in the event that after a failure of the first varistor the connected backup varistor also fails, according to patent document DE 4124321 C2, the backup varistor is disconnected by disconnecting from the voltage either by means of a switch in the transverse branch of the circuit or by means of a switch in the longitudinal branch of the chain. Thus, the protected system is simultaneously disconnected from the network and protected from harmful overvoltages.

Alternatively, it should also be possible to bridge the transverse branch of the circuit by closing the additional switch, so that, in the end, the protected system is short-circuited. The opening of this necessary switch can be done synchronously during the general actuation of the system. If the shutdown of the protected system and / or its short circuit is undesirable, the possibility of the aforementioned switch tripping is canceled using the by-pass or removal of such a tool. However, in principle, additional switches are required to short circuit either the transverse or longitudinal branches of the circuit, which further increases the complexity of the surge arrester, which is already located in a limited installation space.

In particular, in photovoltaic installations, their operating current is approximately equal to the short circuit current due to the parameters of the power source. The classical disconnection during heating of the varistor and its disconnecting device with this application of constant voltage does not achieve the goal, since the system voltage of photovoltaic installations reaches 1000 V, and interruption of 1000-volt DC circuits is generally possible only with significant structural or hardware costs.

Disclosure of invention

Therefore, based on the foregoing, the objective of the invention is to create an improved surge arrester for protection against overvoltages with a housing and at least one discharge element, for example, a varistor, as well as a disconnecting device (disconnector), which, including after possible retrofitting, is able to reliably conduct a short circuit current, so that for a newly assembled or retrofitted arrester in this sense, new fields of application are opened.

The solution to the problem of the invention provides a surge arrester according to the totality of the features of claim 1, the dependent claims being at least expedient embodiments and improvements of the invention.

According to the invention, the known disconnecting devices for overvoltage arresters are equipped with an additional connection, which adds to the existing separation function a short circuit function that allows an emergency current to be carried out for a limited time. It is proposed to carry out additional connection in various ways, so that if necessary, in the surge arrester, implemented accordingly, it also becomes possible to activate it from the outside.

The following description with respect to the disconnecting device is based on the fact that the latter includes a soldering point with solder melting at the corresponding operating temperature. Of course, the disconnecting device can also be made on the basis of other consumable materials, which themselves do not have conductive properties, namely, in the case when the electrical connection to the output circuit is realized through a jumper part, the mechanical position of which is ensured by the use of a melt material.

According to the invention, at least one conductive element is located on the path of the spring-loaded conductor or spring-loaded jumper, the first end of which, when the disconnecting device is activated, contacts the section of the conductor or the jumper.

The second end of the conductive element is connected to a second electrical external terminal. In addition, means are provided to protect the contact point between the conductor portion or jumper and the conductive element from spraying residues of solder or solder material or the aforementioned molten material.

In a preferred embodiment, the conductive element is designed as a jumper in the form of a bracket, the second end of which is connected to the electrical external terminal by tightening the terminal provided for this. Thanks to this, installation is simplified, since you do not have to create contact with the jumper bracket separately.

In another preferred embodiment, the first end of the conductive element has, as it were, a flat shape or the shape of a slightly curved plate, the plate being oriented essentially parallel to the portion of the conductor or jumper, precisely with respect to their position in case of separation.

This parallel arrangement allows you to realize as low resistance as possible, contact and fit on the largest possible surface.

The plate may have on its lower side facing the second end, a recess or ledge, taking on a spray of solder or molten material. Due to this, it is possible to effectively prevent the solder from settling on the plate with the formation of bulges there, causing the appearance of undesirable transition resistance. If necessary, the recess can also accommodate the eroding material of the portion of the conductor or staple.

According to the invention, a later additional mounting of the conductive element into the arrester is possible in order to realize, along with the separation function, also a fault-tolerance function based on a short circuit.

The jumper bracket, preferably provided as a conductive element, has means for mounting it in the housing or on the housing of the arrester. The conductive element has such parameters or such a design that after a predetermined time, the action of the short circuit function is terminated.

The fastening means may include, for example, a groove or recess in the bracket, as well as a corresponding protrusion or counter groove in the housing, to create a geometric closure. Specific modifications to such a fastener, of course, also apply to valid alternatives.

In order to enable selective activation of the conductive element as a contactor acting in the event of a disconnection, an insulating plate is placed between the conductive element and the conductor section or bracket. Alternatively, it is possible to equip the conductive element, at least at its first end, with a removable insulating sheath, for example, in the form of an insulating sleeve. Like the insulating plate, the insulating shell is also removed through a special hole in the housing to unlock the additional short circuit function.

To enable selective activation of the conductive element in one embodiment of the invention, the relative distance between the conductive element and the portion of the conductor or jumper is adjustable. In this case, in the first position, when disconnecting, it is possible for the portion of the conductor or jumper to come into sufficiently close contact with the conductive element. On the other hand, by limiting the course of the portion of the conductor or jumper, it is possible to prevent its contact with the conductive element. With this embodiment, it is permissible to install a mobile eccentric restricting movement or travel.

In order to create the possibility of selective activation of the conductive element as a contactor acting in the event of disconnection, in an additional embodiment, it is possible to use an element restricting the path of movement of the conductor section or jumper, for example, in the form of a finger, a pin or similar stop.

As already shown, it is contemplated to provide an insulating plate or pin or finger accessible externally through the housing, in particular in order to be able to subsequently remove these means.

The activated short circuit function in each case is indicated by an indicator. In this case, it can also be provided that the access to the removal of the insulating plate, finger or pin is sealed. Possible here, for example, a seal in the form of a cork, when removed, removes with it the insulating plate, finger or pin. The surge arrester discharged from the seal in this way reports on the inclusion of the provided additional short circuit function.

Brief List of Drawings

Below the invention is explained in more detail on the basis of a variant implementation, as well as using the figures.

The following are shown:

Figure 1 is a schematic diagram of a spark gap with varistors and combined properties for separation and for short circuit;

Figure 2 is a schematic illustration of an embodiment of a disconnecting device with a switching function in a failed state;

Figure 3 - image similar to figure 2, however, in the tripped and short-circuited position;

Figure 4 is an embodiment of a switching device with removable insulating plates;

On figa and 5b is another embodiment of a switching device, and the short circuit function is controlled by the movement of the conductive element, controlled by an eccentric;

6 is an embodiment of a surge arrester with a housing and with a discharge element based on a varistor, as well as a thermal disconnecting device, and the dividing bracket transfers mechanical movement to the thermal disconnecting device, and in case of separation, short-circuiting occurs using a jumper acting as a conductive element;

Fig.6b is an image similar to Fig.6, but in a separate state and with a tripped short-circuit;

On figa - a detailed image of the end of the jumper staples, having the form of a plate, with a visible recess, in the short circuit position in relation to the switching tongue, and

7 is a circuit diagram with a conductive element as a switching device.

The implementation of the invention

According to the image in FIG. 1, a varistor 2 is connected between the external terminals A and B. This varistor 2 is disconnected using a disconnecting device (switching tongue) 3, which is triggered by thermal exposure. The electrical connection between points a and c exists, as a rule, through a section of a conductor or a jumper, namely in a non-triggered position. In position 3 'the disconnecting device 1 worked, and with the help of a short-circuit bracket 4, which bridges the varistor 2, a connection was established between a and b in the section. The activated or tripped short circuit position is shown in the figure by a dashed line between points a and b. In Fig.2-5, the switching movement is performed under the action of the compression spring 6 (designation 11 in Fig.6 and 6b) after soldering the solder joint.

Figure 2 schematically shows an embodiment of a switching device 1 with a disconnect function and a short circuit function in an un-activated or inactive state.

Powered state, i.e. the position of the short circuit after operation, is presented according to figure 2 in the form of a dotted image between points a and b. As already mentioned, the switching movement after the soldering process occurs under the action of the force of the spring 6. Thus, the tongue 3, which forms a section of the conductor, is simultaneously used to implement the desired short circuit between the fixed terminals A and B, abutting against the conductive element or short-circuit bracket 4.

Based on FIG. 3, an actuated state or a trip position, i.e. the desired short circuit between points A and B, namely the short circuit due to the movement of the switching tongue, which is now in position 3 'of the short circuit.

In the embodiment of FIG. 4, the insulating plate 7 is positioned so that the switching tongue 3 or 3 ′ cannot lie against the locking bracket 4. This means that the travel path of the switching tongue 3, 3 ′ is limited by the insulating plate 7. According to the invention instead of the insulating plate 7, it is also possible to use a finger or a pin, or it is possible to close at least the end of the short-circuit bracket 4, shown shaded, using a removable insulating sleeve.

According to the images in figa and 5b in the switching device 1, it is possible to connect or disable the short circuit function by manually acting on a specific tool, in particular, on the eccentric 8.

Using the eccentric 8, which allows you to set different distances 8 ', 8' 'for the impact, it is possible to change the position of the movable part 4' of the short-circuit bracket relative to the stationary part 4 "of the bracket so that, as shown in Fig.5b, contact is made with the switching tongue 3, impossible in the position of the movable part 4 ′ of the locking bracket in figa. In order to limit the movement of the switching tongue, an emphasis 9 is also provided in this embodiment.

The eccentric 8 through the hole in the dotted case is easily moved to various positions according to the images in figa and 5b, and the visible free working end of the eccentric 8 also clearly indicates which of the corresponding positions is currently taking place (short circuit or not) .

Thus, in the "disconnect" switch position in accordance with Fig. 5a, the short-circuiting bracket 4 'mounted in the center of rotation 5 is outside the range and reach of the switching tongue 3, so that contact along the path a / b is prevented.

In the "short circuit" position, the connection along the path a / b, on the contrary, becomes possible due to the movement of the moving short-circuit bracket 4 within the reach of the switching tongue 3, which is made using the eccentric disk 8 '.

In the embodiment of FIG. 6, an overvoltage protection arrester with an additional short-circuit function is integrated into the housing 10. By means of a rotatable dividing bracket 13 and a tension spring 11, a prestressing force acts on the switching tab 3, which by means of soldering 14 connected to a varistor terminal 16 (not shown) drawn through the wall 15 of the housing.

According to the embodiment of FIG. 6, the conductive element is in the form of a jumper bracket 17. This jumper bracket 17 has a first plate-shaped end 18. The second end of the jumper bracket 17 is connected to the electrical external terminal by tightening the terminal 19 provided for this.

The end 18 in the form of a plate of the jumper bracket 17 has, on its lower side facing the second end, a recess 20 that receives solder, which may be sprayed from the solder 14 when disconnected.

The jumper bracket 17 is fixed on or inside the arrester 10 using the fastening means 21. The distance between the plate-shaped end of the conductive element 18 and the conductor section or the switching tongue 3 is variable or adjustable by bending or folding the plate-shaped end 18. The angle between the position of the plate-shaped end 18 and the position of the switching tongue 3 is decisive. In any case, for the desired reliable closure, the contact of the switching tongue 3 with the plate-shaped end 18 here should be provided on an extensive flat surface.

When the switching tongue is soldered in place of the joint 14 in the position according to the image in FIG. 6, the dividing bracket 13 rotates and at the same time switches the movement of the switching tongue 3 to the end position according to position b, which corresponds to the short circuit position.

It can be seen from the image in FIG. 6 that an advanced surge protection arrester with short circuit function is easily placed in a standard housing for mounting on a DIN bus, and its jumper bracket 17 is easily accessible after removing the case cover not shown. Thus, at minimal cost, it becomes possible to provide surge protection with or without a short circuit function for mounting the arrester, and the implementation of the short circuit function is also possible additionally, subsequently, by the later insertion of the jumper bracket 17.

Figure 6b shows an image of a disconnecting device according to the invention in an implemented device, namely in the tripping state (switch position b is activated).

The recess 20 in the region of the end 18 of the jumper bracket 17 is positioned so that the spike 14 of the switching tongue 3 does not come in contact with the jumper bracket 17. The solder, which can stick or splatter here, is placed in the free space available due to the recess 20 and does not lead to the potential creation of increased transient resistance.

Thus, the solder spot 14 or 14 ′ provided with solder (see FIG. 6a) is not involved in the contact itself on a vast surface. Only part b of the switching tongue 3 'abuts against the surface of the end 18 of the web-jumper 17 having a plate shape.

7 shows a circuit diagram with a conductive element, which is designed as a switching device SE.

With a prolonged short circuit of an overvoltage protection arrester, for example a metal oxide varistor, problems can occur in inverters without transformers in photovoltaic installations, namely, problems caused by the reverse current arising.

In addition, there is a danger of the formation of an electric arc when replacing a short-circuit voltage arrester, since the arrester is in a closed state, and the electric current of the photoelectric generator continues to be generated further. Here, technical personnel cannot measure the voltage, as there is a short circuit. In this case, when trying to replace the arrester, a dangerous electric arc arises.

The bypass formed by the switching device in the event of a short circuit is not designed for long-term perception of the current load. After the emergency current flows for a certain time, the bypass is switched off. The conductive element may have smaller cross-sections of current-carrying parts, which is due to the intentional assignment of insufficient parameters, and as a result, be even cheaper to manufacture.

Thus, the conductive element can be made in the form of a fuse, or it can also include a powerful semiconductor, or form an electric circuit with a powerful semiconductor, moreover, a powerful semiconductor after passing a short circuit current with the initial pulse is transferred to the open state.

The functions performed by the conductive element are presented in Fig. 7, in its right part, by symbolic images of a semiconductor switch or fuse.

разрядник защиты от перенапряжений находится в надлежащем функциональном состоянии.The functional sequence can be represented as follows. Capable of

Surge arrester is in good functional condition.

, т.е. к точке подключения элемента короткого замыкания в байпасе. Элемент SE короткого замыкания закрыт. Электрическая дуга, возникающая при открывании теплового разъединяющего приспособления, проводится контактными элементами и самопроизвольно гаснет при достижении контакта короткого замыкания. Непосредственно после достижения контакта короткого замыкания дуга гаснет, и ток течет через байпас, т.е. через переключающее устройство SE.In case of overload of a surge arrester based on a metal oxide varistor, the output of the thermal isolating device moves to the position

, i.e. to the connection point of the short circuit element in the bypass. Short circuit element SE is closed. The electric arc that occurs when the thermal disconnecting device is opened is carried out by contact elements and spontaneously extinguishes when a short circuit contact is reached. Immediately after reaching the short circuit contact, the arc goes out and the current flows through the bypass, i.e. through the switching device SE.

As switching devices, mechanical switches, fuses, but also powerful semiconductor devices can be used. It is also possible to use spark gaps designed for use in DC voltage circuits. The switching device according to the invention can be integrated into a surge arrester, however, however, a combination with an external switch is also possible. After the shutdown process, the damaged overvoltage protection device is excluded from the electrical circuit, but the power remains. In order to start the opening process of the switching device SE after a certain time, the switching device can be performed, for example, with a reduction in cross-section, like a fuse.

Claims (20)

1. Surge protection arrester with a housing (10) and at least one discharge element, for example, a varistor, as well as a disconnecting device that serves to disconnect the discharge element or discharge elements from the network, and the disconnecting device includes a place (14 ) soldering, which is included in the electrical path (A; B) of the connection within the spark gap, and through the place (14) of the soldering, the movable section of the conductor or the movable conductive jumper (3) is connected or connected to the discharge element, with one side, and a conductor section or jumper, on the other hand, is connected or connected to the first electrical external terminal of the spark gap, which also includes means that create a pre-tension force, for example, a spring (6; 11), and the corresponding force vector is indirectly or directly through the movable dividing bracket (13) acts on the section of the conductor or on the jumper (3) in the direction of separation, characterized in that on the path of the section of the conductor or jumper (3) is located a conductive element (4; 17), the first end of which, when the disconnecting device is activated, is in contact with a section of the conductor or jumper (3), and its second end is connected to the second external electrical terminal, and the conductive element contains a switching device or is made in the form of a switching device. 2. The arrester according to claim 1, characterized in that the conductive element is a jumper bracket (17), the second end of which is connected to an external electrical outlet by tightening the clamp (19) provided for this. 3. The arrester according to claim 1, characterized in that the first end of the conductive element (4; 17) has a plate shape, and the plate in the case of separation is oriented parallel to the conductor section or jumper (3). 4. The arrester according to claim 3, characterized in that the plate or the plate-shaped end has on its lower side facing the second end of the jumper bracket (17) a recess (20) that receives the spray solder. 5. The arrester according to claim 1, characterized in that it is arranged to subsequently insert the conductive element (4; 17) into the arrester in order to realize, along with the disconnection function, the function of ensuring fault tolerance by means of a short circuit. 6. Arrester according to claim 2, characterized in that the jumper bracket (17) has means (21) for mounting it in the arrester housing or on the arbor (10). 7. Arrester according to claim 6, characterized in that the means (21) include a groove or recess in the bracket (17), as well as their corresponding protrusion or counter-groove in the housing (10) to create a geometric circuit. 8. The arrester according to one of claims 1 to 7, characterized in that in order to enable selective activation of the conductive element (4; 17) as an short-circuit acting in the event of separation, an insulating plate is placed between the conductive element and the conductor section or bracket (7 ), or the conductive element (4; 17) at least at its first first end has a removable insulating sheath. 9. The arrester according to one of claims 1 to 7, characterized in that to enable selective activation of the conductive element as a short circuit, the relative distance between the conductive element (4; 17) and the section of the conductor or jumper (3) is adjustable. 10. The arrester according to one of claims 1 to 7, characterized in that to create the possibility of selective activation of the conductive element (4; 17) as a contactor acting in case of disconnection, an element is used that limits the path of movement of the conductor section or jumper (3) for example, in the form of a finger, a pin or similar design. 11. The arrester according to claim 8, characterized in that it is arranged to remove the insulating plate (7) from the outside through the housing (10). 12. Arrester according to claim 9, characterized in that the relative distance is controlled by an eccentric (8), accessible externally through the housing (10), manually or using a tool. 13. The arrester according to claim 1, characterized in that each of the possible states of the short circuit function is signaled by an indicator. 14. The arrester according to claim 1, characterized in that the section of the conductor or jumper (3) consists of inelastic material. 15. The arrester according to claim 9, 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 the switching tongue (3) is changed or adjusted, preferably by bending or bending the first end. 16. The arrester according to claim 1, characterized in that the conductive element is made in the form of a fuse. 17. The arrester according to one of claims 1 to 7, 11-15, characterized in that the conductive element incorporates a powerful semiconductor or forms an electric circuit with a powerful semiconductor, moreover, a powerful semiconductor after passing a short circuit current using an initial pulse is converted to open state. 18. The arrester according to one of claims 1 to 7, 11-15, characterized in that the conductive element has such parameters that after the passage of the short circuit current through it, the conductive connection is disconnected. 19. The arrester according to one of claims 1 to 7, 11-15, characterized in that the conductive element is not designed for long-term withstand short-circuit current. 20. The arrester according to claim 10, characterized in that it is arranged to remove the pin or finger from the outside through the housing (10).

Images