ES2358946T3 - SURVEY PROTECTION DEVICE FOR USE IN CONTINUOUS CURRENT NETWORKS, PARTICULARLY FOR PHOTOVOLTAIC FACILITIES. - Google Patents

Abstract

Surge protection device for use in direct current networks, particularly for photovoltaic installations with a parallel circuit that is energetically coordinated with a first bypass track and a second tripable bypass track, which each have a different reaction behavior relative to disturbing and overvoltage events, in which - the first bypass track has at least one varistor (3), whose residual voltage value is detected and passed to a control circuit (4), in order to determine the energy load of the first bypass track, - the second bypass track has at least one explosor (1), whose trigger input is connected to a first output of the control circuit (4), characterized by the fact that - a third branch is connected in parallel to the first and second bypass track as switching and extinction track, which contain e a short-circuit switch, whose control input is connected to a second output of the control circuit (4), - in which the second bypass track with explosor (1) is activated by the control circuit (4) only when an energy overload of the first bypass track recognized with the help of residual voltage monitoring is expected and in addition, for the effective limitation of the sequential current of the network, the short circuit breaker in the third branch is closed for a predetermined period after if a delay time has elapsed, counted from the reaction of the explosor (1) in the second branch track.

Description

Surge Protection Device for use in direct current networks, particularly for photovoltaic installations.

The invention relates to a device of surge protection for use in networks direct current, particularly for installations photovoltaic, with an energetic parallel connection coordinated a first bypass track and a second track of triggerable bypass (firing), which present respectively a different reaction to events disruptors and surges, according to the generic concept of the claim 1.

The combination of different elements of surge protection to obtain a unit of modular surge protection to limit transient surges is known for example from the DE patent 32 28 471 A1. In it, a limitation of overvoltages produced by maneuvering is carried out by parallel arrangement of an explosor with a varistor with the same efficacy as the limitation of disturbing events that arise from lightning and they have as a rule a much more energy content big.

To do this, according to the state of the art known, the protective elements are distributed over two bypass tracks and coordinated in such a way that they are addressed on a first track mainly the overvoltages caused by maneuvers with an abrupt rising edge and with a contribution relatively low energy and that are directed on a second track those surges with a high energy input, e.g. of a lightning strike.

In addition, according to DE 198 38 776 C2 a circuitry to control the coordination needed during the parallel connection of several protection elements Surge corresponds to the state of the art. So, in the known solution the evaluation of the energy contribution is carried out in a precise protective element, e.g. ex. a varistor and from then a gross protective element is activated, that is a explosor, as needed. The tracks provided in this case by consequently they are energetically coordinated, that is in the sense that for a component necessary for this it is captured and evaluated the energy contribution in the first track and in case of exceeding a limit value or several critical limit value parameters are performed a process of switching from the first track to the second track.

US Patent 5,325,259 A describes a surge protection device for a capacity connected in series with two bypass tracks. A hint of bypass contains an explosor and the other bypass track It contains a power switch. After activation of explosor of one of the bypass tracks, the explosor is switched off again by closing the power switch in the Another bypass track. One such protection device against surges however not suitable for current networks continuous, since due to the capacity no flow can flow DC. In addition, the switch connection speed power is very low and during the switch switching Power arcs can be produced.

They have long been known in the lightning protection technique, some explosors capable of supporting lightning currents, which are mainly used in the field of low tensions Its subsequent technical development is based on a ignition device that allows to determine within wide limits the timing of the main discharge path of such a trigger explosive, being able to be tuned optimum ignition timing, eg with the residual voltage of a varistor arranged in parallel. By the association of tension residual of a varistor element to the current conducted to through it you can deduct the energy load arising from through the varistor until the moment of ignition of the explosor.

According to the configuration of a shot described in Patent DE 199 52 004 B4 there is the possibility of adjusting different moments of ignition and its duration with time with help of at least two residual voltage values and thus optimize further coordination This is the case, for example, the immediate ignition of the explosor in case of a brief pulse of current by the varistor no before a relatively high peak current value, while this in a long-lasting momentum is already the case with a relatively low crest value, as soon as this exceed a time signal that is outside the time of the short duration boost.

Of the above mentioned is consequently a task of the invention indicate a device of perfected surge protection, which is specially adapted for use in direct current networks and in these particularly for photovoltaic installations. This surge protection device must be performed in a modular way and be suitable for the derivation of lightning strikes and lightning currents related to this, is say under such conditions that appear in the current system continued mentioned. This is how levels vary in solar installations of voltage and service currents, which is not the case in other AC networks. The problem of the use of surge protection device preferably in the industrial photovoltaic installations sector consists also in that there appear continuous tensions of the order of 1000 V.

The solution of the task of the invention is performed by a surge protection device according to the combination of features according to claim 1, representing the secondary claims at least configurations and timely improvements.

The protection device against surges consists of several functional units that are housed on a common support plate, containing the plate support devices to mechanically fix the units functional and allowing their electrical connections to each other in the as soon as possible considering compatibility electromagnetic

In the device of protection against Overvoltages for use in DC networks are refers to an energy-coordinated parallel connection of a first bypass track and a second bypass track triplable (triggerable), the two bypass tracks having a different reaction to disturbing events and given surges.

The first bypass track has at least a varistor, whose residual voltage value is captured and passed to a control circuit, to determine the energy load of this First bypass track.

The second bypass track has at least an explosor, whose trigger input is in communication with a first output of the control circuit.

A third branch is connected in parallel to the first and second bypass track as a switching track and extinguishing track containing a short circuit breaker consisting of at least one power transistor, whose input of control is connected to a second output of the control circuit. In this point should be made the observation that instead of a power transistor can also be used other elements that connect quickly, like p. ex. Thyristors or similar.

The second diversion bypass track It is only activated by the control circuit when a energy overload, recognized with the help of surveillance of residual voltage, from the first branch track, preferably varistor In addition, for the effective suppression of the current successive network, the short circuit breaker is closed, it is say activated on the third branch for a period of time preset after the delay time has elapsed, counted to Start the response of the explosor on the second track.

The reaction of the explosor on the second track of bypass is recognized by monitoring the system voltage in as for the presence of voltage drops with the help of the circuit mentioned command.

Alternatively, a sensor may be provided. of current to recognize the reaction of the explosor in the second bypass track.

The control circuit comprises a generator of clock to set the delay time and / or the time period of short circuit breaker connection.

The period of connection time in a variant The preferred embodiment of the invention is of the order of 10 \ mus and 3 msf.

In the situation of a short circuit the flowing current in the third branch and in case of an overload, the at least one power transistor is passed to a high state ohmic resistance

In case of a current overload particularly of the impulse current type, the first and / or the second bypass track can be activated again in the sense of retroactive coordination.

The delay time to activate the switch short circuit or the at least one power transistor is set in such a way that the pulse lengths of normalized shock current pulses.

Since in the case of a derivation it is not present a system voltage, the control circuit has a power accumulation unit for safe operation also in the case of a referral.

For grounding according to the technique of Lightning rod installations, the protection device against overvoltages in a configuration is provided with an insulation of Sparks that are inserted into the ground.

The invention must be explained below. more in detail with the help of an embodiment as well as with Help figures.

Here they show:

Fig. 1 a perspective representation of the mechanical structure of the protection device against surges with the respective functional units;

Fig. 1a a detail of the protection device against surges with an explosor as well as an insulation of Sparks planned optionally;

Fig. 2 a diagram of connections of principle of surge protection device with respect to a connection mode between the L + and L- poles of an installation photovoltaic;

Fig. 2a the electrical scheme of the device surge protection with spark insulation additional;

Fig. 2b the interconnection of the units functional, as arranged on the upper face of the support plate according to Fig. 1;

Fig. 2c the interconnection of the units functional, as arranged on the underside of the support plate according to Fig. 1, as well as

Fig. 3 current and voltage curves during derivation process in a schematic representation.

The protection device against Surge according to Fig. 1 and 1a comprises a support stage 5, on which two elements of varistor 3 are arranged (VDR1 and VDR2) on the upper face. In the image shown on the right, find a trigger circuit that is a component of the control circuit serving as a CCU coordination and monitoring unit, reference Four.

The explosion of the second bypass track It is equipped with reference 1 and the spark insulation of the reference 2. In Fig. 1 and 1a the ground track is represented with reference 6 and the ground connection with reference 6 ' (Fig. 1).

On the first bypass track according to the Fig. 2 flows the current I_ {p1}. The second bypass track with a triggered explosor it carries the current I_ {p2}.

On the switching or extinguishing track with a transistor as short circuit breaker current flows I_ {p3}. In the second bypass track there is still another sensor of current S which is guided on an input of the control circuit CCU (E3).

The voltage on the varistor VDR2, that is U_ {VDR}, access inputs E1 and E2 of the CCU control circuit, whose output A1 is connected to the trigger input of the second bypass track explosor.

The A2 output of the CCU control circuit is is in communication with the base, that is, the entrance of transistor connection in the third branch.

U_ {VDR} represents the residual voltage over varistor VDR2, U_ {Z} the ignition voltage or voltage of Reactor reaction, U_ {BO} arc maintenance voltage of the explosor and U_ {TR} the short-circuit voltage on the switching transistor of the extinguishing track or switch Short circuit

The coordination of the first track with the current I_ {p1} with that of the second track leading the current I_ {p2}, occurs through the CCU control circuit, activating this by means of a command signal the trigger device of the explosive trigger on the second track due to the load energy of the first track.

As a result, the download path main of the explosor is ignited by an ignition pulse corresponding and the bypass current that has been derived to beginning with the first track switches to the second track. A condition for a complete switching, in which the first track it is completely without current, it is an arc voltage to be possible low with respect to the varistor voltage, which occurs after its reaction on the discharge path of the explosor

Due to the switching, the varistor suffers a discharge, assuming the most powerful explosor in some ways the bypass process and therefore the shock current.

Since the varistor track on these moments is no longer electrically active, the explosor itself must terminate the referral process, so that they are then presented New normal network conditions. This means that in in many cases the explosor must disconnect, that is, remove the subsequent network current applied after having the impulse of shock current decreased. This current sequential network or called tracking current arises, in how much or while the "floating" voltage of the network on the explosor is greater than its arc tension.

Tracking currents can represent a considerable load for the explosor according to the current level and / or duration of time and therefore generally should not be abandoned in the opinion of its energy balance. In an unregulated state and uncontrolled can cause the explosor to age in advance and finally fails.

It is therefore necessary to avoid the appearance of monitoring currents or limit these temporarily as well as in The amplitude.

For the solution of the problem of follow-up currents should now be taken into account that in DC networks of solar installations are presented very high voltage values.

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According to the invention, the first measure must be avoiding the appearance of a tracking current, taking place the reaction of the explosor only when there is a risk of energy overload for the varistor. If this risk does not exist, the varistor assumes the derivation process completely and from this way a tracking current due to operation is impossible.

The energy evaluation is carried out in the CCU control circuit that preferably generates with the help of the residual voltage curve an oriented trigger signal of Selective way by the varistor, causing the explosor firing react.

Since the connection of the second track of referral is made depending on the performance of the varistors on the first track, then it turns out a wide area selectable, within which the varistor can perform the complete derivation of the current pulse, without there being a part the risk of an overload of the varistor and on the other hand if A tracking current is presented.

This area can be expanded by selectively oriented evaluation with the help of the circuit command regarding simple evaluation methods, so that eg in case of a low energy shock current pulse of the 8/20 \ mus waveform, a certain type of varistor it can be loaded up to 10 kA and the same type in another pulse of 10/350 \ mus waveform energy-rich current can be loaded up to 1.5 kA.

With the method described above it is impossible for a tracking current is already present with currents of weak energy impulse, which may arise, for example switching voltages or indirect lightning influences moderated in a relatively frequent sequence. Also for the total range of indirect lightning influences, represented by 8/20 \ mus waveform, no currents are expected from tracing. On the contrary, the explosor is connected additionally according to your destination in case of direct influences of the ray reproduced by the 10/350 \ mus waveform. It has to have therefore few current events of Comparison tracking due to this configuration.

As another measure to prevent the presence of Tracking currents are monitored first, when the explosor is connected directly and when the course begins of a delay time. If you evaluate the moment in which you have pulse current decreased or if the time for preset delay, the switch that short-circuits the arc voltage of the explosor in the third branch, that is, in the switching and extinguishing track, so that the tracking current that is about to start or has started and the explosor that is then without power goes out. After a short connection time, the short circuit is removed again by opening the switch on the extinguishing track and the original operating status is restored, as has existed before the referral process.

Compared to known methods, the solution can be easily implemented, saving space and economically This is the advantage that they can be exploited the configurations of explosors, which of the usual way until now they are only used in voltage networks alternate or have been designed for networks of this type.

As can already be deduced from the diagrams of blocks, the extinguishing track features a switch short circuit that is physically able to meet both electrical and mechanical requirements, as presented in relation with the switching process. In addition, the switch is controllable so that a connection and disconnection coordinated by the CCU control circuit.

In relation to the switching process there is a requirement that, in addition to the capacity of a high connection load, the switching process itself occurs without the formation of an electric arc per connection. That is why laborious spark arrester cameras can be saved and therefore a high need in space that would result additionally. Since it is possible to turn off the tracking current within a short time of connection or achieve a resetting of the isolation distance of an explosor, the switch is designed both to be quickly connected and also to be disconnected again, that is, it has high switching speed
dynamic.

As for the advantages that result from the implementation of the theory of invention, it should still be noted the next.

The effort to turn off a current of monitoring in case of a continuous voltage of approx. 1000 V is with the use of a very high explosor and usually requires very expensive measures for the extinction of the electric arc. The usually quite cheap explosives are sized and designed for mastering alternating voltages in the low field tension. The tensions to dominate are clearly lower in this application case, the electric arc is also turned off regardless of the natural zero return of the current. In a continuous voltage there is no natural zero return of the current and the explosors must therefore work according to the principle of shutdown of the direct current. Switching power needed for a successful disconnection of the current from monitoring is considerable and requires developed explosors of a special way as well as explosives that require a lot of space and are very expensive, which have to adapt exclusively for the aforementioned application case. He aging of such an explosive is considerable because of the switching power needed that has been increased. Finally, the corresponding explosors must have cameras complicated spark arresters with a high need in space.

With the invention is achieved by the track Short-circuit returnable separately make usable the usual and conventional low voltage field explosors, which have only a sufficient power off of the tracking current in case of alternating current and voltages clearly lower, also for applications in the range of continuous voltages up to 1000 V.

Advantageous is also the drastic reduction of the converted power inside the explosor, since the voltage of > 1000V electric arc required in the shutdown principle DC current should not be generated, but the voltage arc eg it can only be 30 V. In case of direct current, Switching power, explosor charge and aging by consequently they can be reduced by more than factor 30.

The basic principle according to the invention is based in turning off the tracking current not with the help of the explosor, but in shifting the off function for the sequential current from the network to a semiconductor component without aging and without Electric arc. Therefore there is practically a separation functional and a distribution of functions between the explosor and the semiconductor component. The combination of the explosor and the varistor performs in total the function of the derivation of quantities disturbing in the form of impulse, assuming the semiconductor the arc tracking power off function electric. A condition for this is the complete switching of the tracking current from the explosor to the track semiconductor and a sufficient reestabilization of the explosor both in height as well as speed, before the element from the semiconductor disconnect the tracking current. The Complete switching is achieved in that the voltage drop of the track shutdown is lower than the arc voltage of the explosor The semiconductor connection time depends on the difference of voltages U_ {TR} and U_ {BO} as well as time reestabilization of the explosor, as this is described more in detail in the exemplary embodiment with reference to Fig. 3 of the same.

In order to determine exactly the moment of additional connection to the extinguishing track as well as to avoid that a pulse current flows over it or the current of follow up stay too long on the bypass track of the explosor, not only a quick reaction connection is necessary of the short circuit breaker but also a technical circuit device that offers the possibility of a coupling with a sensory unit for track monitoring of the explosor

Thus, the current is detectable by the explosor, so that the switch can be activated short circuit directly after the current decrease impulse An unwanted tracking current is avoided by the explosor and the explosive energy load is reduced as well as the aging due to impulse current guidance, such as results from transient overvoltage. As switch of short circuit a power transistor is preferably used that is not subject to any phenomenon of aging or wear, under the condition that their limit values are not exceeded electric

According to the invention, care has been taken that connection parts, of which a large emission part interfering, they are decoupled from those components that They are exposed to a sensitivity to disturbance. This is performs so that the individual functions are divided into groups that gather on the one hand only disturbing sources or insensitive connection parts, and on the other hand those that are sensitive to disturbance, with combinations of the groups with each other in the shortest way despite the separation space.

The short circuit breaker can be composed of cascading transistors, to achieve in state disconnected a high tensile strength found by above the protection level of the protection device surges

To prevent deterioration of the power switch transistor, this is switched with high ohmic resistance, when reaches or exceeds the maximum permissible integral of the current. In current overload case for the connection case, this almost planned emergency shutdown eventually results in the extinction or switching process is interrupted. It is so so much necessary to distinguish such emergency disconnection from a regular switching process and start contrary to this others extinction attempts, until a process of regular switching

As a regular switching process governs that which has the fixed total connection time set without interruption. The connection time is made up of the time of extinction and the rest time needed by the explosor generally depending on the load to pass the area low ohmic resistance conductor to the high insulating area ohmic resistance Accordingly, the precise connection time may be in the range of approx. 10 \ mus to 3 ms.

If the current overload takes place after the transistors are already connected, the disconnection of emergency must also occur and as described must generate one or more other shutdown cycles if necessary, until A regular switching process is initiated.

Emergency disconnection results in the short circuit switch switch off track with high ohmic resistance This however also means that, for the if the current overload is a pulse current, the voltage can rise widely via the off track, of so that it results in a new reaction of the first or even of the second bypass track. Therefore the device surge protection advantageously presents not only a simple, but also retroactive, continuous coordination, in which the last phase of the provision (third branch) in the case of need affects the first phase.

Therefore, the protection device against surges can also overcome so-called lightning strikes multiple, in which several intervals appear at certain intervals overvoltages or current impulses, when it should take place another electric charge during the activated phase of the track extinction. By this re-coupling function, almost automatically the corresponding step of the arrester, that is the first or second bypass track.

The CCU control circuit is intended for detect all information about temporary transcripts of the functional groups and to issue the corresponding orders of adjustment or control to the adjustment elements. One of the functions The most important of the CCU control circuit is the coordination of functions implemented in the extinction track, in addition to the evaluation of varistor load and signal emission resulting for selective firing of the explosor.

The auxiliary functions belong to them that are related to emergency disconnection, too those that are accompanied by the shutdown process, that is beginning with the recognition that the explosor has reacted to the event-controlled short circuit breaker connection or time until even its disconnection or redisparo with the process Definitive regular switching.

The detection that the explosor has responded, It can be done so that the applied system voltage is controlled with respect to voltage drops that typically correspond to the reaction of an explosor and present eg a certain speed of tension growth, leaving a certain voltage value simultaneously below its minimum value.

The voltage drops from external processes that correspond to this frame, are therefore advantageously detected also, so it can also be controlled and turned off eg a disturbing electric arc produced by insulation errors in the total circuit.

This information is evaluated by the CCU control circuit and apply for example as a starting condition for the delay time and after this time the short circuit track.

The delay time can be adjusted from so that it disappears or bridges eg the lengths of impulse of the normalized shock current pulses of the waveform 8/20 \ mus or 10/350 \ mus.

For an electric pulse 10/350 \ mus there would be then estimate a delay time of approx. 2 ms, which possibly also in case of shorter drives a tracking current corresponding approximately to this time frame.

Given the function of the emergency disconnection, a shorter ineffective time can also be set than orients on the shortest electric pulse of 8/20 \ mus, eg a 60 \ mus time, so that in case of longer pulses, eg 10/350 \ mus, emergency disconnection is activated cyclically for so long that the current is greater than the permissible connection current in the short circuit.

In the supposed ineffective time of 60 \ mus the short circuit track tries to activate the switch short circuit by several periodic connection cycles to start the switching, until finally the remaining value of the pulse current has decreased to the connection current admissible. With this measure you can make a default temporal in the sense of a cycle time by adjusting the delay time and after this time must have Place a connection attempt for switching. The advantage of this adjustment is in the reduction of the current phase of monitoring particularly in case of high currents of Follow up to wait.

In another embodiment of the invention, it has a current sensor in the second bypass track, whose signal detection is adjustable by the control circuit in the pulse current or tracking current or both types of stream. With this there is the possibility of starting the process of switching regardless of a set fixed delay time already at the moment when the impulse current has dropped over the explosor at a value that corresponds to the connection current admissible on the extinction track. Due to the reaction time more reduced connection with the high switching speed of the short circuit breakers in the extinguishing track do not therefore produces no tracking current. This is another possibility to put the connection time if possible near the transition from the decreasing shock current to the current of follow-up to be applied if high currents of tracing.

The embodiments described for the detection of connection conditions for the track Short circuit show that adaptability and flexibility is possible over a wide range using the control circuit. In the subsequent functions that the control circuit can perform is also possible a combination or logical linkage of different characteristics, for example expanding the criteria of connection, creating a permanent short circuit desired for certain situations or limiting to a value determined a persistent overvoltage for a long time and that appears outside the transitional time interval. Other tasks that have to be carried out with the CCU control circuit is also a automatic extension of the connection time, when within a default time span in principle is not done any extinction or inclusion of the heating temperature of the explosor in the calculation of the switch on time short circuit, that is, the extinction time.

Under the facts that throughout the bypass process the system voltage is practically not available, the control circuit has an energy accumulator which ensures the necessary power supply for this phase.

As already explained, the power switch semiconductor, as a short circuit breaker, consists preferably in a power transistor as a component appropriate has the connection and disconnection functions required in short time intervals also in case of high connection currents In this case they are imaginable too alternative solutions that use eg a switchable thyristor or a thyristor or series fired gas arrester with a varistor or a PTC element.

With reference to Fig. 2a and 2c and under certain conditions of use require that the circuit active, eg the poles characterized in solar installations with L + / L must be safely separated from ground potential (ground) or must be installed.

From the technical point of view of lightning protection, in this case the necessary grounding must take place by means of a spark insulation. For this case of necessity, such a spark insulation 2 (see Fig. 1 and 1a) can be integrated in the modular surge protection device, opening the ground rail 6 and connecting it by means of the spark insulation to the connection to 6 'land. There being no need in this regard, this explosor 2 does not proceed and is replaced by a continuous ground lane by the factory (connection
6 and 6 ').

Fig. 3 shows typical curves of current and of tension during the bypass process.

The "impulse" area is referred to in this case. to the derivation process itself until the magnitude decreases of influence U_ {ray}, while the area "system" represents the cancellation phase with a tracking current appearing on the explosor until the voltage return of the system.

For the current switching shown in the individual phases I_ {p1} until I_ {p3} govern the condition next:

U_ {TR} < U_ {BO} < U_ {VDR}

In the time interval t0 to t1, the magnitude of influence U_ {ray} requests in principle the varistor in the bypass track I_ {p1} and causes tension there U_ {VDR}.

If this voltage exceeds the permissible load of the varistor (a value adjusted to the quantity and duration) in relation with the corresponding current, the current at time t1 switches to the diversion track I_ {p2} of the explosor according to the representation according to Fig. 1 and 1a, so that the voltage of the varistor U_ {VDR} intervenes in the value U_ {BO} below the system voltage U_ {dc}. Once the magnitude of influence, appears on the explosor 1 at time t2 a sequential network current that is switched at time t3 to the short circuit track I_ {p3} and is disconnected by it in the moment t4. Between moments t3 and t4 the voltage drops to the transistor voltage U_ {TR}.

The time interval t2 to t3 represents a interval, in which in the present case a current of unwanted tracking on the explosor (scratched representation). In combination with a sensor, particularly a sensor S current, and a quick short circuit breaker, can be shortened this unwanted time interval until it no longer represent no additional charge beyond the electric charge of impulse for the explosor.

In short, the protection device against Surge according to the invention has properties, for DC systems, which allow the use of explosors according to the state of the art in direct current applications, aspiring solutions to avoid a tracking current while the explosor is included only if necessary in the derivation process. Tracking currents are avoided from way that the short circuit breaker in the extinguishing track commutes immediately after the decrease of the current of impulse or tracking currents may be limited temporarily, while a voltage drop defined in the voltage of the system drives a delay time and after this time has elapsed, the short circuit breaker is activated on the track of extinction.

Next to the track of the explosor itself is provided another bypass track with a protective element against overvoltage that can drive lower impulse currents even average, without creating the same tracking streams. Additionally there is an extinction track that recognizes a tracking current and that causes a current switching of the track of the explosor in the extinction track due to the short circuit of the arc voltage of the explosor. The process of extinction is controlled and eventually repeated, as soon as acknowledge that no regular extinction has taken place.

The protection device against surges is coordinated so that the first track of shunt with the varistor switch in case of overload to the second highest performance bypass track with explosor. A once the current pulse in the track of the explosive has decreased, a switching on the extinction track takes place. In case of overload of the short circuit extinction track can be switch again with an emergency disconnection at the first varistor track and from where it can eventually be switched to The second track with explosor.

Reference List

one

Trigger Blast (FS1)

2

Spark Isolation (FS2)

2'

Connection support

3

Varistor Element (VDR1 / VDR2)

4

Command circuit as coordination unit and control (CCU)

5

Support plate

6

Dirt lane

6 '

Ground connection

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Documents cited in the description

This list of related documents by the applicant has been collected exclusively for information of the reader and is not part of the European patent document. The it has been made with the greatest diligence; the EPO without However, it assumes no responsibility for any errors or omissions

Patent documents mentioned in the description

DE 3228471 A1 [0002]

US 5325259 A [0005]

DE 19838776 C2 [0004]

DE 19952004 B4 [0007]

Claims (10)

1. Protection device against surges for use in direct current networks, particularly for photovoltaic systems with a circuit energy-coordinated parallel of a first track of bypass and a second tripable bypass track, which each have a different relative reaction behavior to disturbing events and surges, in which

-

the first bypass track has at least one varistor (3), whose residual voltage value is detected and passed to a circuit of command (4), in order to determine the energy load of the first bypass track,

-

the second bypass track has at least one explosor (1), whose trigger input is connected to a first output of the control circuit (4), characterized by the fact that

-

a third branch is connected in parallel to the first and second track bypass as switching and extinguishing track, which It contains a short circuit switch, whose control input is connected to a second output of the control circuit (4),

-

at which the second bypass track with explosor (1) is activated by the control circuit (4) only when an overload is expected energy of the first bypass track recognized with the help of residual voltage monitoring and also for limitation effective sequential network current, the switch short circuit in the third branch is closed for a period default after a delay time has elapsed, counted from the reaction of the explosor (1) on the second track of derivation.

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2. Surge protection device according to claim 1, characterized in that the reaction of the explosor (1) in the second bypass track is recognized by monitoring the system voltage in relation to the occurrence of voltage drops , with the help of the control circuit (4). 3. Surge protection device according to claim 1, characterized in that a current sensor is provided on the second branch track to recognize the reaction of the explosor (1). 4. Surge protection device according to one of the preceding claims, characterized in that the control circuit (4) has a clock generator for setting the delay time and / or the connection time of the short circuit breaker. 5. Surge protection device according to claim 4, characterized in that the period of connection time is of the order of between 10 µm and 3 ms. 6. Surge protection device according to one of the preceding claims, characterized in that in the short circuit situation, the flowing current in the third branch is monitored and in case of overload, a power transistor used as a short circuit breaker It is passed to an open state of high ohmic resistance. 7. Surge protection device according to claim 6, characterized in that in the event of a current overload, particularly of the type of impulse current, the first and / or the second bypass track are activated. 8. Surge protection device according to one of the preceding claims, characterized in that the delay time is adjusted such that the pulse lengths of normalized shock current pulses are bridged. 9. Surge protection device according to one of the preceding claims, characterized in that the control circuit (4) has an energy accumulation unit for operation in the case of bypass. 10. Surge protection device according to one of the preceding claims, characterized in that a spark insulation (2) is provided for earthing according to the lightning protection technique, which is integrated into the grounding.