SK18398A3 - Protection circuit arrangement for surge arrester - Google Patents

Abstract

A protection circuit is aimed at the overvoltage shunt arran gement wired into a supply network comprising first shunts (6) wi red between the phase conductor (L), eventually phase conductors (L1, L2, L3) and neutral conductor (N), eventually earthing (PE) of the system and a second shunt (5) wired between the neutral co nductor (N) and earthing (PE) of the system. The protection circu it contains a detection device (2) detecting at least the current through the second shunt (5) and a switch device, which can be t riggered by the detection device (2). The switch device is formed by a contact system (10) containing one or more contacts (1), wh ich is connected through the trip device (4) to the detection dev ice (2), whilst the first contact (1) is connected parallely to t he second shunt (5) placed between the neutral conductor (N) and the earthing (PE) of the system and/or first terminals of one or more second contacts (1) are connected with the terminals (9) of one, eventually first shunt (6) connected with the devices (7) fo r protection against the overcurrents and the second connections of this one or these more contacts (1) are connected with the neu tral conduct (N) or with the earthing (PE) of the system.

Description

Technical field

BACKGROUND OF THE INVENTION The present invention relates to an overvoltage isolating device that is connected in a voltage supply network and comprises a first conductor, a phase conductor or phase conductors, and a neutral or grounding system, as well as a second conductor connected between the conductor between the neutral conductor and ground. system; consisting of a detection device measuring at least the second current drawn and a switching device which can be operated by the detection device.

BACKGROUND OF THE INVENTION

Similar separating devices are known in various designs, for example the leakage separator described in Austrian patent application no. A205 / 91st

In all previously known isolation devices, a disconnecting device is provided as a disconnecting device which is connected in series with a protected overvoltage leakage and is opened when the excessively high current at the line frequency flows through the leakage.

This inadmissible leakage current, which must therefore be disconnected by the decoupling device, occurs when the respective leakage is damaged (for example after overloading by transient overvoltage) or when so-called leakage currents occur. Temporary Over Voltages (TOV), which have been gaining importance recently. These short-term overvoltages are transient overvoltage overvoltages with the frequency of the network, which are generated as follows:

The low-voltage network used for the system-supplied power supply is a medium-voltage transformer.

Both networks are grounded using a common grounding system.

When a ground fault occurs with the medium voltage grid, a current flow occurs, resulting in a voltage drop across the earth resistance.

but it will increase by the mentioned voltage drop to

In this way, the grounding resistance has the potential of the zero point and hence the potential of the neutral conductor of the low voltage network. The potential difference between the phase conductor and the ground will increase equally in the low voltage grid.

The short-term overvoltage (TOV) amplitude is considerably lower than the transient, for example, lightning-induced overvoltage, but can reach several times the nominal voltage between the phase conductor and ground, what does the aquifer say? into a conductive state. As far as the leakage elements are concerned, the most unpleasant feature of short-term overvoltage (TOV) is their relatively long exposure time. Such overvoltages can last for several hundred milliseconds and therefore occur in a common 50Hz network for several periods.

This, however, is associated with a long action of the leakage current and, last but not least, with a high thermal load on the leakage elements, therefore, in this case too, the separating device must separate the leakages from the mains or protect it.

The above-mentioned leakage-induced leakage currents can be reliably disconnected in the previously known, normally-closed contact isolators (only the rated mains voltage prevails), but if short-term overvoltage (TOV) occurs, it must be taken into account several times the voltage of the mains, which results in two electric openings being bridged by the electric arc and therefore it is not possible to ensure an effective disconnection in this type of construction.

Due to the series connection with the leads, the contacts are flowing through high surge currents, which are the result of transient overvoltages, causing the contacts to become very warm, which can also lead to sintering of part of the contact when overloaded. In this way, the leakage separator becomes unusable.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide a decoupling device of the aforementioned type, a reliable line having regard to the voltage conditions existing under short-term overvoltage (TOV).

This object is achieved according to the invention in that the switching device consists of a contact assembly which can be operated by a triggering device connected to the detection device and which bridges the second conductor located between the neutral conductor and the system ground and / or shorting the devices. For protection against overcurrent connection of the first conductor 4 ₍ or first conductors with neutral conductor or system ground), thereby activating the overcurrent protection device, preferably fuses, which are connected between the phase conductor and the phase conductors and the first conductors, respectively.

Separation of the first leads is not effected by opening the contacts but by activating the overcurrent protection device, preferably by melting the respective fuse, which can be caused by an extremely fast feasible short-circuiting of the phases with neutral conductor or grounding of the system.

Compared to the contacts, it is possible to easily realize a larger "contact distance" with such fuses, so that a stable electric arc can be reliably and at a minimum cost avoided and thus the disconnection can be delayed or prevented. In addition, the transient leakage currents do not flow through the contacts, so there can be no problems associated with these currents.

To further develop the invention, it is contemplated that the detection device is connected to the triggering device by an evaluation circuit, such as a delay circuit, an energy storage circuit, or other similar circuit.

In addition to reshaping the signal coming from the detection device into a signal that would be useful for controlling the triggering device, the reaction characteristics of the decoupling device, such as the response delay and the like, can also be set by the evaluation circuit.

According to a preferred embodiment of the invention, it is envisaged that the evaluation circuit determines at least the second leads absorbed energy, and when a predeterminable amount of energy is less than or equal to the maximum energy absorption limit of the second lead, the trigger device is activated.

In this way, the energy supply and therefore the heat supply are stopped before or when the maximum permissible temperature rise of the leakage is reached, therefore it is possible to prevent the occurrence of heat-induced damage or destruction. In the case of small or very short-acting currents (which are therefore inverse to the aquifer), it is not possible to trigger a disconnection.

In this context, it may be assumed in the further development that the evaluation circuit is constituted by the invention by a series connection of the circuit which over time integrates the signal coming from the detection device and the limit value of the determining circuit.

This design can be applied to the leakage elements whose voltage is approximately constant in the low ohmic state, and this voltage is known.

Thus, the device for detecting said voltage is, as a whole, substantially simplified by the energy detection device.

at least one detection

It is furthermore possible to provide a device for detecting the leakage current of the first leakage, respectively of the leads and of the leakage, of the first determining energy, and a different evaluation circuit connected thereto, respectively of the leakage electrically adjustable after reaching a power less than or equal to the maximum to the possible absorbed amount of energy of the first lead or first leads respectively, the trigger device or the evaluation circuit triggers another trigger device which shortens the first by means of a different contact system, in fact by means of additional contacts from the lead or the first contact system. zv ..

In this way the leakage leads, since this achieves reliable protection of the first leakage protection will not depend on the leakage current of the second leakage.

Another feature of the invention may be that the devices consist of a current detection measuring transformer, i, j

t total current measuring transformer ™ ¹ · devices. her

s

Thus, it is possible to create a signal that ivani ⁰ ^^ separated from the leakage current and the j ^e YDA considerably smaller, making it possible sig ⁿ ^^ treated with much less cost.

According to one preferred embodiment, it is possible to assume that the trigger device! formed by the drive winding of the relay or the switch protection system are formed by the contacts of the relay itself, as a switch protection. In this way, a particularly compact and functionally reliable design of the felling device and the contact system is realized.

In another realization of the take-off _you can _on a signaling device, n / example optical, acoustic or the like to be / has been operated at the conclusion of the contact system. /

Thus, it is possible to simply highlight SPO _reindeer responsible, but currently absent instructions to the necessity of re-introduction of the relevant circuit into operation ·

It is furthermore possible to assume that the triggering devices automatically reopen the contact systems after the decaying or leakage current has been interrupted.

As a result, the re-commissioning of the decoupling device is limited only to the replacement or connection of the overcurrent protection device.

In this context, however, it may be advantageous for the signaling device to remain activated after opening the contact assemblies, as indicated by the necessity to carry out the reason that there is still a manual replacement of the overcurrent protection device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention of the preferred examples shown in the attached figures.

The embodiments in which the wires are connected are explained in more detail

Fig. 1.1 to 1.3 show diagrams of the separation devices according to the invention connected to single-phase consumer systems.

Fig. 2.1 to 2.3 show circuit diagrams of separation devices according to the invention connected to three-phase consumer systems.

Fig. 3 shows a circuit diagram of the separating devices of FIG. 1.1 with a detailed embodiment of the evaluation circuit and the triggering device.

Fig. Figures 4.1 and 4.2 show a schematic circuit diagram of a separating device according to the invention, the evaluation circuit of which detects the electrical energy that has been dissipated by the second lead,

Fig. 5 shows, in the form of a current / time diagram, the maximum possible energy absorption limit of the varistor.

Fig. 6.1 to 6.4 illustrate various embodiments of a circuit that detects the energy drawn by a lead.

Fig. Figures 7.1 and 7.2 of the single-phase separators show the circuit diagrams of the devices according to FIG. 1.2, which is also monitored.

energy absorption by first leads

Fig. Fig. 8.1 to show diagrams of three-phase separators which are also monitored by the device according to the energy absorption. 2.3, first leads

DETAILED DESCRIPTION OF THE INVENTION

In the embodiment of FIG. 1.1, it is assumed that the overvoltage leakage connection between the phase conductor L and the grounding of the PE system comprises a downcomer 6 and between the neutral conductor N and the grounding of the PE system comprises a downcomer 5. In this embodiment, but also in the following examples, these are preferably made of varistors, but may also be other voltage-dependent elements.

The protective circuit provided for the protection of these leads 5, 6 comprises a detection device 2 which is connected to a common node 8 of both leads 5, 6 and also to the earthing of the PE system. This detection device 2 is thus connected in series with both the leads 5, 6 and serves to detect the total or leakage current flowing. Another part of the separation device is a switch device which ensures the disconnection of the leakage network or which controls the switch connected between the neutral conductor N and the grounding of the system from the conductors 5 of the PE system.

already mentioned detection

This device can be activated by the device

This separating device comprises two essential components, and equipment 7_ to protect against overcurrent, which is connected between the phase conductor IL and the first leakage ^i, 6 and lowering device £, which is connected to a detection device 2_ leakage current which controls the contact assembly 10th

If the current from the detector 2 detects the device from the figures, an inadmissible high signal to the trigger

6, sends the corresponding one

4, which in the following contact system 10. As clearly implies involved between

5, the second conductor 5, the neutral conductor N and the grounding of the PE system and the conductor S, connected ^{to the} protection device 7 ^, are short-circuited to the neutral conductor N, the step being carried out.

connection 9 of the first before overcurrent,

In this way, a pure short circuit between the phase conductor L and the neutral conductor N causes a correspondingly high current through the protection device 7 to activate it and thus

The second downcomer 5 is thus protected from the network.

high voltage overcurrent, which has a leakage voltage from the A 6 conductor, since both of its connections are in a low ohmic conductive path, which causes a considerable voltage to not occur at each other of these connections.

In the arrangement of the surge arresters of FIG. 1.2, it is believed that the first zvodje 6_ ^_ is connected between the phase conductor L and a neutral conductor N and the other of leads' 5 is connected between the neutral wire N and grounding system of PE (as is the case in FIG. 1.1). In this case, too, the protective circuit comprises a leakage current detection device 2 which is connected to a triggering device that controls the contact system 10.

As mentioned at the outset, short-term overvoltage (TOV) arises by first increasing the potential of the neutral conductor N_ of the low system with the ground of the transformer, at the same time increasing the voltage of the voltage conductor L and L1, L2, L3. due to PE grounding. In this way, it is sufficient to detect the leakage current by observing the leakage current 5 located between the neutral conductor N and the earthing of the system P E.

This principle underlies the embodiment of FIG. 1.2, wherein the detection device 2 only monitors the current through the lead. The contact assembly 10 comprises only one contact 7 which bridges the conductor 5. The conductor 5 is similar to FIG. 1.1 protected from inadmissible high voltages by means of its zigzag connection of both its connections.

As shown in FIG. 1.2, the overcurrent protection device 7 can be removed from the circuit of the first downcomer and connected in front of the entire system. In this way, when the separating device is activated, not only the conductor 5, 6 but also the entire consumer system are separated from the network. In this connection, the overcurrent protection device 7 may consist of a house connection circuit breaker, which is always available. This kind of arrangement of the overcurrent protection device 7 can be envisaged in each of the following exemplary embodiments of the invention.

The embodiment according to FIG. 1.3 has a similar construction to the embodiment of FIG. 1.1. The contact assembly 10 again comprises two contacts 1, one of which provides the aforementioned bypass 5, but in contrast to FIG. 1.1 creates a second contact 1 * x. a connection of the grounding of the PE system and connects to the first leakage 6 connected to the overcurrent protection device 7. However, this does not change the basic functional principle, and in this case too, a high current is activated, activating the overcurrent protection device 7, thereby achieving a separation of the lead 6 from the mains.

In FIG. 2.1 to 2.3 illustrate exemplary embodiments of the invention suitable for three-phase consumer systems. By their construction, they correspond to the single-phase embodiments of the invention according to FIG. 1.1 to 1.3. More specifically, FIG. 2.1 shows an analogous embodiment of FIG. 1.1 (phase conductors L1, L2, L3 are short-circuited with neutral conductor N_), fig. 2.2 is equivalent to the embodiment of FIG. 1.3 (phase conductors L1, L2, L3 are short-circuited with PE grounding) and fig. 2.3 is similar to the embodiment of FIG. 1.2 (the leads 6 are between the phase conductors L1, L2, L3 and the neutral conductor N, only the current through the lead 5 is monitored). For a consistent functional principle of single-phase and three-phase separation devices, a new detailed description of the function will be omitted.

The triggering device 4 can be implemented in two basic ways. According to a first variant, the triggering device 6 can only activate the shutdown process, the restoring of the initial state, i.e. the opening of the contact assembly 10, has to be carried out manually. Thus, a trigger device which is already known from conductor switch protections or FI switch protections can be used as the trigger device. According to a second variant, the actuation device 6 automatically returns to its rest position upon activation of the overcurrent protection device 7, respectively after the echo or interruption of the leakage current, an example of this variant being given in the following description.

The contacts 1 of the contact assembly 10 are formed by known mechanical contacts, but can also be realized by electronic elements such as triacs.

The detection device 2 may in principle be formed by any current-sensitive sensor device. Particularly suitable are current transformers or total current transformers.

In general, the signal coming from the detector 2 may not be suitable for direct control of the trigger device 6. Therefore, in all the illustrated embodiments of the invention, it is envisaged to connect the detection device 2 to the triggering device 6 by means of an evaluation circuit 3. In this evaluation circuit 3, the signal coming from the detecting device 2 can be converted correspondingly into a signal suitable for the triggering device 4.

In addition, the triggering properties of the entire surge arrester can be influenced by the evaluation circuit 2. By means of delay circuits or energy storage circuits (which can be realized in such a way that the signal of the detecting device 2 will have to charge the capacitor before the signal is fed further to the triggering device)

surges, which ones they can a flat z v o d'm i 5, 6. N a v i a c is a possible

which filter out all suppose frequency filters, signals that do not have frequency networks and are therefore triggered by transient overvoltages that need to be dissipated. In this way, it is also possible to prevent startup.

In FIG. 3 shows a specific, particularly simple embodiment of the triggering device and the contact assembly 10. Both of these components are realized by one single component, either a relay or a switch protection, whose excitation windings form the trigger devices 4 and their contacts form the contact assembly 10. The relay is supplied with mains voltage, the phase conductor being routed via an electronic switch 31 which can be controlled by the detector 2. This switch 31 comprises a DC bridge 32, whose AC connections are connected to the phase conductor L and the relay. In the DC circuit, a thyristor 33 is provided which is activated by the evaluation circuit 3. In this way, current is allowed to flow through the drive winding of the relay and triggered. If in this case a monostable relay or switch protection is used, that is to say a device whose armature is brought to a rest position by a spring force in the tension-free state, the automatic return of the triggering device 4 to the original state is ensured.

The detection device 2 is indirectly connected here only to the symbolically indicated evaluation circuit 3, which in the aforementioned manner serves to adapt the signal or to create a kind of trigger behavior.

In addition to the previously described non-essential components of the separating device, the separating device may comprise a signaling device by means of which it would be possible to indicate the separation performed.

The signaling device may be of any kind, for example an optical lamp, a movable signal plate or the like, or an acoustic signal, for example, a siren tone.

The signaling device would be activated when the contact system 10 closes, for example by the auxiliary contact of this contact system - and would alert the system operator of the need to replace or restart the overcurrent protection device 7 and the trigger device 6, respectively. If a triggering device 4 with a self-restoring to the original position is used, the signaling device will preferably remain unaffected by this resetting, the signaling device will therefore still remain activated, since the overcurrent protection device 7 has to be put into operation anyway. If this operation is carried out, the signaling device can be switched off, which can again be done automatically or manually.

When a leakage current is generated, the conductor absorbs the voltage and converts it into heat. Only when the thermal stress exceeds the maximum possible absorption limit of the downcomer does the downcomer or damage to the downcomer occur.

So far, it has only been said that the separation or bridging of the leakages 5 must take place when they are flowed at an "excessively high current." Taking into account the above-mentioned knowledge regarding the maximum possible energy absorption limit of the leakage, it can be stated that it is not necessary immediately to detect a leakage or bridging the leakage immediately after the detection of the excessively high leakage current. It is much more practical to monitor the energy absorption of the lead and trigger the separation or bridging, respectively, shortly before or until the maximum possible energy absorption limit is reached.

In FIG. Figures 4, 7 and 8 show exemplary embodiments of the invention in which this cut-off criterion is used.

These examples will be explained in the following description.

The energy applied to the resistance element can be calculated using the formula

For this reason, in the circuit diagram of FIG. 4.1 (which by its structure corresponds to its circuit described in FIG. 1.2 above) envisages a device 3 'which, by means of a detection device 2 k, detects the voltage at the leakage 5 and also the leakage current 5 and carries out the above calculation.

As soon as the calculated amount of energy reaches preset values of the maximum possible energy absorption limit, or values just below the maximum energy absorption limit, as determined by the limit value of the determining circuit 3 '', the triggering device 4 is activated and the lead ¹ '5 is bridged as described above.

In case that a varistor is used as a protective conductor 5, which is very common in practice, the

4.1. In fact, the varistor has the property that the connections have a value, and the connections can be made according to FIG.

It is known from the coohm state that the voltage occurring constant, which is practically independent of its current, is known.

The energy supplied is therefore rather proportional one single not known j - i * t therefore Integration p r ú d u over time. To execute above calculation is therefore needs determine the product i * t. Ako j is displayed FIG. 4.2. must multiply with yours

of absorbed energy determining the evaluation circuit 3 per varistor include:

H circuit 3, which over time integrates signal proportional leakage current and which is coming from detection devices  limit value defines the task 3 ' symbol)

by a comparator) which can actuate the triggering device 4, which will take place no later than when the energy supplied to the lead 5 exceeds the maximum possible absorption limit.

The dotted filter circuit, as will be explained later, only provides a non-binding and preliminary assumption that it is not used.

In a particularly simple manner, the described disconnection condition can be represented graphically, as in FIG. 5. The starting point of this diagram is the equation for the maximum possible energy absorption limit of the varistor:

Wmax = u * i * t, where u = const.

therefore

W _max is proportional to i * t

The plotted line g is the set of all points where the product i * t acquires a constant value which, when multiplied by a constant voltage, gives the maximum possible energy absorption limit of the varistor.

Suppose that the tripping characteristic of the separating device according to the invention (not important as its course) is at all its points below the line g. Thereafter, too much energy may be present on the protected lead 5 to damage it.

Specific embodiments of the integration circuit 3 are shown in FIG. 6.1 to 6.4. The integrating components are selected with respect to the form of the signal coming from the detection device 11. In the embodiment of FIG. 6.1, a current transformer is used as the detection device 2. Therefore, the signal which is proportional to the leakage current is again the current. After rectifying by diode 61, this signal can simply be integrated over time by means of a capacitor 60, because

U _c = 1 / C and dt

Thus, the integration results in an instantaneous voltage across the capacitor 60.

When using a sensor that returns a voltage signal, a circuit that can integrate voltage values must be used. The simplest example of this circuit is an operational amplifier connected as an integrator (see Figure 6.1).

The capacitor voltage is supplied by

A zener diode 70 for the trigger relay 71, wherein the trigger relay 71 is coupled to the trigger device 4. If the triggering device 4 is formed by the drive winding of the relay or switch protection (as described above), the drive winding may be connected to the circuit instead of the trigger relay. Once the capacitor voltage breakdown voltage

The zener diode exceeds the charge value

70, with a capacitor

0 via a

isolation or bypassing the leakage relay 5, 6.

team

The capacitance of the diode 70 is run in front of the capacitor 60 and the breakdown voltage is selected in such a way that the maximum possible limit is reached

Zener disconnects the energy absorption of the lead.

The recognition of the limit value hitherto described by the Zener diode 70 may, in the spirit of the invention, be carried out by other means, as in the circuit of FIG. 6.2 to 6.4.

In FIG. 6.2, the Zener diode is replaced by a transistor assembly 11 in a closing direction, which in the simplest case consists of a single transistor. The base-emitter transition of this transistor is connected in series with the trigger relay 7 1, at a precisely defined voltage, it breaks (similar to the Zener diode) and in this way allows current to flow through the trigger relay 71. Serial connection of multiple transistors (indicated by the dotted line) can easily increase the breakdown voltage of the transistor assembly 11.

Normally, only small currents can flow through the base-emitter transistor, which are usually too small to trigger the trigger relay 71. Therefore, it is necessary to supplement the transistor structure 22 with additional circuit elements of greater power. An example of this addition is shown in FIG. 3.6

The transistor structure 11 consists of transistors 12 and 13 as well as resistors 14 and 15. The capacitor 16 may be advantageous because it shortens the interference signals. The transistors 12 and 13 are interconnected by positive feedback. The resistors 14 and 15 serve for the high ohmic connection of the transistor assembly 21, thereby ensuring that the transistor assembly 11 does not appear to be a load on the capacitor 60 during its charging. It is advisable to choose transistors 1 4, ϋ ^with high current gain. Once the transistor structure 11 becomes conductive in its closing direction, the voltage drop across the resistor 14 will ensure that the transistor 12 goes into a conductive state. The current, which then flows through the resistor 15, causes a voltage drop which causes the transistor 13 to go into a conductive state. An even greater current will then flow through the resistor 14, since the voltage drop across the conductive transistor 13 is substantially lower.

Thus, it can be said that the trigger control current flows practically only through the conductive passage of the emitter collector of transistors 12 and can therefore have the amplitude necessary to activate the trigger relay.

71, thereby avoiding any damage.

According to another embodiment shown in FIG.

6.4, the recognition of the threshold is realized by the op-amps

21, which is connected as a comparator.

The integration of the signal, which is proportional to the leakage current, is carried out by another operating which, thanks to the connection with the resistor 19 and the amplifier 17, the capacitor 18 has the characteristics of a known integrator.

In FIG. 6.1 to 6.4, the limit recognition circuits or the integration circuits shown can be used in any combination. For example, the capacitor 60 of FIG. 6.1 to 6.3 may be replaced by the operational amplifier 17 of FIG. 4.6 Conversely, the transistor structure 11 of FIG. 6.2, 6.3 it is possible to replace the operational amplifier 21 which acts as a comparator.

In the event of an inadmissible high voltage, the downcomer must perform its function without being disturbed in any way, that is, without the downcomer being activated. In the separator described so far, this condition is maintained only when the amount of surge surge energy is less than the maximum possible energy absorption limit of the downcomer.

However, the purpose of using the downcomer is to dissipate the overvoltage independently of their energy content, even if the downcomer should be potentially destroyed. The electrical strength against the surge currents of the leakage separator, which has so far been considered only for 'energy-poor surge surges', should therefore be extended to 'energy-rich surge surges'.

In order to solve this problem, it is contemplated according to the invention not to take into account, when calculating the amount of lead-in power supplied by the protected lead, whose frequency is greater than the mains frequency, i.e. currents caused by short surges caused by lightning.

Circumferentially this task is realized in that a filter circuit 22 is connected downstream of the detecting device 2, which limits the leakage current proportional to the signal whose frequency is lower or equal to the frequency of the network. The aforementioned short-term overvoltage (TOV) have a grid frequency and are therefore fully included in the calculation of the amount of energy absorbed and therefore the leakage separator responds to them. In order to ensure that the unsuitable frequencies are suppressed, the filter circuit 22 must have a frequency response similar to that of the low pass or band pass and be tuned to the network frequency.

In FIG. 4.2, this filter circuit 22 is indicated by a dashed line. A specific embodiment can be a simple RC-gate (as in Figures 6.1 to 6.3), but also any other known circuit having the necessary transmission properties.

In the exemplary embodiments of FIG. 4.1 and 4.2, only the absorption of second lead energy A5 is monitored.

As shown in FIG.

7.1, it is also part of the idea of the invention to additionally follow the first seduction ”6. In FIG. 7.1, a separate evaluation circuit 30 and a separate triggering device 30 are provided for the purpose of determining the current leakage 6.

40, which controls the contact lead 6. For both leads, the system 10 0 bridges

5, the amount of energy received is monitored independently of each other from the network.

A simplification of this circuit is shown in FIG. 2.7 Here they are; <

although the currents flowing through the leads 5, 6 independently determined and integrated over time, the two evaluation circuits 30, 30 used, however, control the common triggering device 4, so that each evaluation circuit 30, 30 independently of the other circuit can activate the triggering a device 4, which is symbolized by a member OR into which their terminals are introduced. The contact assembly 10, which is connected to the trigger device 6, comprises here two contacts 1 by means of which it is possible simultaneously to bridge the two leakages 5, 6.

In the single-phase embodiments of FIG. 1.1 and 1.3, only one common detection device 2 per lead * 5, 6 is provided. In this case, the sum of the two leakage currents is determined and this sum current is taken as the basis for calculating the amount of energy absorbed. Depending on the circumstances, disconnection can be accomplished in two ways. In the first case, the disconnection is carried out at the earliest when the sum of the energy absorption limits of the two leads 5, 6 has been reached (but a uniform distribution of the summation current between the two leads is assumed). In the latter case, the disconnection takes place after reaching the maximum possible absorption limit of one of the leads (thereby preventing damage even in the case of an uneven distribution of the summation current between the two leads 5, 6 in each case).

The same applies to the three-phase embodiments of FIG. 2.1 and 2.2, here too, the sum of all outflows is determined. The cut-off cut-off value can be chosen between one and four times the energy absorption limit of one lead.

In the circuit of FIG. 2.3 it can be assumed that it is detected only the amount of energy received IE "deception 5 (similar to the single-phase embodiment of FIG. 4.2), and that the leakage is ^{observed, RY.} The connection variants of FIG. 8.1 to 8.5.

According to FIG. 8.1, a separate detection device 20 with a respective evaluation circuit 30, a triggering device 40 and a contact system 100 for bridging the corresponding lead 6 is provided for each lead 6.

According to FIG. 8.2, although the individual leads are monitored by separate detection devices 20 and respective evaluation circuits 30, the bridging of the first leads 6 is, however, carried out by a single contact assembly 100 comprising three mechanically connected contacts 1 'and controlled by a single trigger 4 The individual evaluation circuits 30 can independently control the triggering device 40.

In the embodiment of FIG. 8.3 on ic '. bridging the first leads and the second lead 5 &apos; provides for the use of a common contact assembly 100 which would be coupled to a triggering device 4 which would again be operable by each evaluation circuit 30, 30.

In addition to the separate monitoring of the individual first leads 6, it is also possible to monitor only the sum of the currents flowing through them. This idea is realized by the connections according to FIG. 8.4 and 8.5.

According to FIG. 8.4, separate start devices 40, 40 with respective separate contact systems 10, 10 are provided for the second downstream and first downstream 6. In FIG. 8.5, although the first leads o and the second leads SS. monitored independently of each other, but are bridged by means of a common trigger device 4.

Said additional detecting device 20, evaluation circuit 30 and trigger device 40 have the same function as the detection device 2, evaluation circuit 30 and trigger device 60, and are therefore preferably constructed in the same manner.

Claims (10)

1. Surge isolation device. i.e., a seductive arrangement which is connected in a voltage supply network and comprises, between the phase conductor, the first conductor (6), the connected (L) and the phase conductors (L1, L2, L3) and neutral conductor (N) or system ground (PE) as well as a second downcomer (5) connected between the neutral conductor (N) and system ground (PE); comprising a detection device (2) measuring at least a second leakage current (5) and a switching device which can be operated by a detection device (2), characterized in that the switching device consists of a contact assembly (10) which it is possible to control the triggering device (4) connected to the detection device (2) and which bridges the second conductor * (5), located between the neutral conductor (N) and the system ground (PE), and / or shorting the device (7) ) for overcurrent protection K. connections (9) of the first downcomer (6) or the first \ C downcomers (6) with neutral conductor (N) or grounding of the system (PE) and thus activates the protection device (7) before overcurrents, preferably fusible fuses which are plugged in between phase conductor (L), respectively phase conductors it (L1, L2, L3) and first leads (6). Separation device according to claim 1, characterized in that the detection device (2) is connected to the triggering device (4) by means of an evaluation circuit (3), such as a delay circuit, an energy storage circuit or the like. Separation device according to claim 2, characterized in that the evaluation circuit (f (3) determines at least the second leads (5) the energy received and when a predeterminable amount of energy is reached which is less than or equal to the maximum possible energy absorption limit In the second guide ~ (5), the trigger device (4) is activated (Fig. 1.1, 1.3, 2.1, 2.3, 4.1, 4.2). The surge arrester device according to claim 1 3, characterized in that the evaluation circuit (3) is constituted by a series connection of the circuit (3), which over time integrates the incoming signal from the detection device (2) and the limit value of the determining circuit (3 ''). Separation device according to claim 3 or m, characterized in that at least one (20) detecting or detecting the first leakage current (6) of the detection device by the first leakage conductor, respectively, determines the connection to the m (6), another (6), the evaluation circuit (30) and / or the leads (6) absorbed the electrical energy, wherein a predeterminable amount of energy that is less than or equal to the maximum absorbable amount of energy first is reached. - the lead (6) and the first leads (6) respectively, the evaluation circuit (30) triggers another trigger device (40) or trigger device (4) which, by means of a different contact assembly (100) or additional contacts ( 10) shortens the first downcomer ~ (6), (1) of the contact system or the first downcomer (6) (Fig. 7.8). Separation device according to one of claims 1 to 6 5, characterized in that the detection devices (2 20) consists of a current measuring transformer, a measuring current transformer, or a similar device. Separation device according to one of Claims 1 to 7 6, characterized in that the triggering devices (4, 40) are constituted by the winding of the relay or the switch protection and the contact systems (10, 100) are formed by the contacts of the same relay or the switch protection. Separation device according to one of the preceding claims, characterized in that a signaling device, for example optical, acoustic or the like, is provided which is activated when the contact assembly (10) is closed. Separation device according to one of the preceding claims, characterized in that, after the echoing or interruption of the leakage current, the starting devices (4) have been switched off. 40) reopen contact systems by themselves (10, 100). A separation device according to claims 8 and 9, characterized in that the signaling device remains activated after the contact assemblies (10, 100) have been opened.