EP3130048A1

EP3130048A1 - Protective device and protective system for electrical circuits, and method for controlling the protective system

Info

Publication number: EP3130048A1
Application number: EP15713376.0A
Authority: EP
Inventors: Uros Platise
Original assignee: Energijski Konduktorji d o o
Current assignee: Energijski Konduktorji d o o
Priority date: 2014-04-07
Filing date: 2015-03-21
Publication date: 2017-02-15
Also published as: US20170025845A1; DE102014004912A1; JP6629292B2; WO2015154850A1; US10424910B2; CN106575866A; JP2017516281A

Abstract

The invention relates to a protective device (1) comprising a microswitch (2) which is serially connected to a fuse (3) or a circuit breaker, a current measuring unit (5), a storage unit (4), and a control unit (6). At least one current value range is stored on the storage unit (4). The current measuring unit (5) is designed to measure current intensities in the protective device (1) and to generate current values which represent the measured current intensities. The control unit (6) is designed to process the current values, to open the microswitch (2) if a current value lies in the current value range, and to reclose the microswitch (2) after being opened. The invention further relates to a protective system for electrical circuits with multiple protective devices (1) of the aforementioned type and to a method for controlling the protective system.

Description

Protective device and circuit protection system and method of controlling the protection system

The invention relates to a protective device and a protection system for circuits and methods for controlling the protection system.

Circuits of, for example, apartments, houses or office buildings with one or more consumers are typically protected by a protective device in the form of a fuse or circuit breaker from long-term overcurrents and short-circuit currents. In this case, usually several circuits are operated in parallel and powered by at least one power line with power, the protective devices between the circuits and the power line are arranged and together form a protection system. After a fuse or circuit breaker has tripped, typically either replacement or reconnection of the respective protection device is required, which is cumbersome and incurs costs. Furthermore, with conventional fuses and circuit breakers, the power consumption of individual circuits can neither be reconstructed nor controlled, which is of particular interest in times of rising electricity prices and fluctuating power availability in the power line.

From GB 2 450 426 A are with fuses or

Circuit-breakers connected to circuit breakers are known, can be opened and closed by means of a remote control to open or close circuits. Power measurement units can measure and transmit power to the circuits protected by the fuses or circuit breakers so that a remote control user can decide, based on the power consumed by the circuits, whether to disconnect a circuit or remain closed. The system shown in GB 2 450 426 A allows the circuits to be protected against long-term overcurrents and short-circuit currents, as hitherto customary, by means of their fuses or circuit breakers, so that their replacement still requires replacement or restarting. GB 2 450 426 A

shown system is expensive in terms of apparatus, takes in particular in the field of fuses or circuit breaker additional space to complete and allows only to a very limited extent, a control of the protection system of several fuses or circuit breakers and power consumption in individual circuits.

It is therefore an object of the present invention to provide an improved, particularly safe and comfortable protective device and a protective system and method for its control, with which the power consumption in circuits can be controlled better automatically. The object is achieved by a protective device according to claim 1, a protection system according to claim 13 and a method according to claim 17 or 23.

The protective device according to the invention is characterized in that it is one with a fuse or a

Circuit breaker series-connected micro-switch, a current measuring unit, a memory unit and a control unit comprises. At least one current value ranges is stored on the memory unit. The current measurement unit is configured to measure currents in the protection device as well as the measured ones

To generate currents representing current levels. The control unit is configured to process the current values, to open the microswitch when a current value is in the current value range and to close the microswitch after opening.

For this purpose, the protective device preferably has an input which can be connected to a current-carrying current line and an output which can be connected to a circuit. The fuse or circuit breaker and the microswitch are then arranged in series between the input and the output, the current measuring unit measuring, for example, currents between the microswitch and the output and generating the measured current values representing current values.

The at least one current value range is preferably stored on the memory unit as a data record. special Preferably, at least two current value ranges are stored on the memory unit, namely a long-term overcurrent current value range, which defines a long-term overcurrent state, and one

Short-circuit current value range, which defines a short-circuit current state. The storage unit may be e.g. integrated into the control unit or be formed by a separate unit.

The control unit can access and process the current values generated by the current measurement unit. For example, processing includes adding, subtracting, comparing, storing, deleting or forwarding. The control unit may also be particularly advantageous also configured to process any other values except current values. In particular, the control unit can be set up to compare the current values generated by the current measuring unit with the current value ranges stored on the storage unit.

If the control unit determines in such a comparison that the current values lie in one of the current value ranges stored on the memory unit, eg in a current value range defining the long-term overcurrent state or the short-circuit current state, then it can open the microswitch and thereby disconnecting the circuit of the protection device from the mains. The microswitch can thus be opened automatically by means of the control unit before the fuse or the circuit breaker would trigger. The fuse or circuit breaker therefore only serves as a redundant backup means when the microswitch should not open in time. Replacement or re-closing after release can be dispensed with because the microswitch can be automatically closed again after it has been opened, eg after a definable period of time or if another determinable criterion is present. The protective device is particularly compact and may for example have the same dimensions as conventional fuse protection devices or circuit breakers, so that they can be easily replaced by the protection device according to the invention. In addition, the protective device according to the invention may comprise actuating means by means of which the microswitch can be opened and closed manually, without the need for a power supply, which is particularly advantageous in the event of failure of one or more components of the protective device or their power supply is.

According to a first embodiment, it is advantageously provided that at least one maximum duration value assigned to the at least one current value range is stored on the memory unit and the control unit is set up to open the microswitch if current values are longer than the maximum duration value in the current value range. According to this embodiment, at least one pair consisting of a current value range and a maximum duration value is stored on the memory unit of the protective device. Preferably, at least two pairs of associated current value ranges and maximum duration values are stored on the memory unit, namely a long-term overcurrent current value range with an associated long-term maximum current current maximum value, which defines for which duration a long-term overcurrent condition is tolerated at most , and a short-circuit current value range having an associated short-circuit current maximum duration value, which defines for what duration a short-circuit current condition is tolerated at most.

The control unit is set up to measure the duration, how long by the current measurement unit successively generated current values are in the current value range to compare the measured duration with the stored on the storage unit permanent maximum value, which is associated with the relevant current value range, and when the maximum permissible value is exceeded, the microswitch is opened, whereby a circuit connected to the protective device can be disconnected from the power line without the fuse or the circuit breaker tripping.

According to a further embodiment, the

Protection device advantageously at least one further measuring unit comprising a temperature measuring unit, a voltage measuring unit, an energy measuring unit, an impedance measuring unit, a frequency measuring unit and a power measuring unit, wherein on the storage unit at least one further value range corresponding to the type of the respective further measuring unit is deposited. The further measuring unit is set up for measurements corresponding to its type

perform and produce corresponding measured values. The control unit is set up to process the measured values and to open the microswitch if a measured value lies in the relevant further value range.

If the protective device comprises a temperature measuring unit, at least one temperature value range, preferably an excess temperature value range, is stored on the memory unit, which defines which overtemperature measured values are not tolerated. As fuses or circuit breakers typically a

Bimetallic element or have a thin wire, which overheat in long-term overcurrents and / or durchbren, the temperature-measuring unit will preferably be arranged so that they the temperature in the immediate vicinity of the bimetal or the wire of the fuse or of the circuit breaker can measure. A stored on the SpeI chereinheit temperature range then preferably refers to the temperature of the

Bimetal element or the wire. Also, it is advantageously provided in this context that the Temperature measuring unit can measure the ambient temperature of the fuse or the circuit breaker and refers to a temperature range stored on the storage unit on the ambient temperature. In particular, this embodiment with a temperature sensor makes a contribution to further increasing the safety of the protective device, in that the opening and closing of the microswitch can be carried out on the basis of two independently measured variables (current and temperature), both of which are particularly significant parameters for a long-term Overcurrent are.

If the protective device comprises at least one further measuring unit in the form of a frequency, voltage, power or energy measuring unit, this makes it possible, in particular, to detect an overload of a power line connected to the protective device particularly early and reliably and by immediate automatic opening of the microswitch To take load from the power line in the shortest possible time, thereby again increasing the quality of the current in the power line.

If the protective device comprises a frequency or voltage measuring unit, at least one frequency and one voltage value range are stored on the memory unit, which define which frequency or voltage measured values are not tolerated. Such frequency or voltage value ranges preferably define an underfrequency or undervoltage Condition, which are given when the frequency or voltages measured in the circuit by the frequency or voltage measuring unit are more than a definable limit below the normal mains frequency or voltage. Such unwanted underfrequency conditions typically occur when the load in the circuit is too large, eg, caused by a load jump or an abrupt decrease in the line current. This undesirable condition is also referred to as "brown-out", which can cause damage to devices in the circuit and lead to a power failure in the network.

If the protective device comprises a power or an energy measuring unit, then at least one power or energy value range is present on the memory unit

which defines which power or energy measured values are not tolerated. Preferably, such a power or energy value range defines a state of excessive power consumption or excessive energy consumption, which are given when the power consumption measured by the power measurement unit or the energy consumption measured by the energy measurement unit exceeds a respectively definable limit value.

If the protective device comprises an impedance measurement unit, then at least one impedance value range is stored on the memory unit, which defines which impedance measurement values are not tolerated. Preferably Such an impedance value range defines a high-impedance state, which occurs when the impedance measured by the impedance measuring unit exceeds a definable limit value. In particular, a high impedance state can be used as an indicator that all loads within the circuit are ready to be disconnected from the power line, eg

when some loads are completely switched off and some loads are only in stand-by mode. The control unit of the protective device can automatically effect a corresponding separation by opening the microswitch, which in particular contributes to reducing the electrosmog caused by the circuit. The impedance measuring unit can be designed as a separate component or in the

Be integrated current measuring unit.

The explanations below for the temperature measuring unit apply analogously to the other above-mentioned further measuring units, so that reference is made to avoid repetition thereof. The control unit can access the temperature measured values generated by the temperature measuring unit and compare them with the at least one temperature value range stored on the storage unit. If the control unit determines in such a comparison that the temperature measured values lie in a temperature value range stored on the memory unit, eg an over-temperature state of the wire of a fuse Overtemperature value range, it can open the microswitch.

The above-described embodiment of the protective device according to the invention with at least one further measuring unit can be advantageously modified such that the control unit is set up to open the microswitch even if a current value generated by the current measuring unit is not stored in a current stored on the storage unit. Range of values is located, no power value ranges and / or maximum duration values are stored on the memory unit, the control unit is not set up to process current values and / or the protection device has no current measuring unit.

Particularly advantageous is further provided that on the memory unit at least one of the at least one further value range assigned further

Maximum value is stored and the control unit is set up to open the microswitch if readings longer than the other

Maximum duration value in the wider value range. The pair of a further value range and a further maximum duration value associated therewith define for which duration a state which is defined by the further value range is tolerated at most without the control unit opening the microswitch. The control unit may measure the duration of how long the measurements of the above said further measuring units are in a value range corresponding to the respective type, compare the measured duration with the stored on the memory unit further maximum duration value, which is associated with the relevant further range of values, and open the microswitch when the further maximum value is exceeded.

It is furthermore particularly advantageously provided that the value ranges and maximum duration values can be processed. This allows the protection device to be used e.g. particularly flexible and easy to adapt to different fuses and circuit breakers as well as power lines, power grids and circuits.

According to a further embodiment, it is advantageously provided that the control unit is set up by processing energy measured values generated by the energy measuring unit to generate an energy consumption report which can be stored on the storage unit and which contains energy consumption in the circuit during a definable period of time. The energy consumed in the circuit of the protective device can be detected in the definable period, for example on a day, a week, a month or a year. The definable period is preferably stored on the memory unit of the protective device, so that the control unit can access it. The energy consumption report that can be stored on the storage unit can be accessed from outside the protection device, so that it can be further processed and / or displayed, for example.

In this connection, it is particularly advantageously provided that the control unit is set up to differentiate between different loads that consume energy in the circuit and to generate an energy consumption report for each individual load. This is made possible by evaluation of the

Load profile of the circuit, which can be determined in detail, which load has consumed in a fixed period of time how much energy.

According to a further preferred embodiment, the protection device comprises at least one communication interface. At least one is preferred

Communication interface provided which is adapted to establish a direct communicative connection with at least one other protection device. Furthermore, the communication interface can be set up to communicate with communication interfaces of external devices, eg computers or mobile phones, in particular smartphones. The communication interface is preferably set up to transmit data records stored on the memory unit and to receive data records to be stored on the memory unit, wherein said data sets may comprise value ranges, maximum duration values, time periods, current values, further measured values or energy consumption reports by way of example only. In particular, you can Also, external devices of an electricity supplier or a network operator communicate with the communication interface and thus in particular influence which microswitches are to be opened and / or closed under which conditions.

In this context, it is particularly advantageous that the communication interface is set up to communicate wirelessly. The elimination of wiring can be saved in particular space and installation costs. As communication interfaces in this context, e.g. W-LAN, Bluetooth, infrared or other wireless interfaces are used.

According to a further embodiment, it is advantageously provided that the communication interface is set up to provide access to the current values and / or the measured values. For this example, IP addresses can be stored on the storage unit, which are compared with devices that want to establish a connection to the communication interface. In particular, the communication interface can provide access to the values generated by the measuring units to a device of an electricity provider which supplies power to a power line connected to the protective device, so that the power supplier receives information in real time, for example, about the current in the circuit of the protective device received power receives and this information, for example, the Control of power distribution in its supply network can use.

Furthermore, the communication interface can advantageously be set up to at least partially deny access to the memory unit. As a result, in particular a contribution is made to protect the privacy of the protection device user. For example, the communication interface can be denied access to the energy consumption reports stored on the storage unit to an electricity provider.

The protection system according to the invention according to claim 13 comprises several of the protection devices according to the invention described above, each having at least one

Communication interface, wherein the protective devices are communicatively connected by communication interfaces. In particular, the protection devices can exchange current values and other generated values with each other via the communication interfaces. Likewise, at least one protective device can be particularly configured to control the microswitch of at least one other protective device.

For example, in the protection system, one of the

Protection devices - a "master protection device" as it were - assign a maximum permissible current value to other protection devices. The said other protective devices of the protection system are preferably located within a fuse box, but also provided that protective devices are connected outside the fuse box directly in front of a relevant electrical load and exchange their generated current values with at least one protective device within the fuse box.

If a respective protective device measures a current value which exceeds the maximum permissible current value assigned to it, then it can be provided in a particularly simple manner that the control unit of the relevant

Protective device whose ikroschalter opens. However, it is particularly preferred that the master protection device can react flexibly to such a state. Thus, it is advantageously provided that the other protection devices transmit their generated current values to the master protection device by means of the communication interfaces. Due to the received current values and a definable maximum current value for the protection system, the master protection device can now change the maximum permissible current values for the other protection devices such that as many microswitches of the protection devices as possible can remain closed.

In this way, the power consumption in the

Protective devices associated circuits are particularly flexible balanced among the protection devices. The protection devices, in particular the master protection devices, multiple protection systems can also communicate with each other in the above manner, so that a corresponding compensation of the power consumption is also possible at the level of several protection systems.

According to a first embodiment of the protection system according to the invention is advantageously provided that the ^! Protective devices are communicatively connected in series by the communication interfaces and thereby form a communication chain. This embodiment, which in the minimum case may comprise two and basically any number of protection devices according to the invention, allows the protection devices of the communication chain to exchange information particularly quickly with one another and that the opening and / or closing of the microswitch can be tuned particularly quickly between the protection devices. For example, a first and a last protection device, which are arranged at the two ends of the communication chain, each having a communication interface, by which they are each communicatively connected to the immediately adjacent protection device. The protection devices between the first and the last protection device may, for example, each have two communication interfaces, by which they are each connected communicatively with their neighboring protection devices. In particular, current values, measured values and other data sets can be transmitted to the other protective devices via the communication chain particularly quickly, processed and used to control the opening

and / or closing of microswitches of the protective devices are used. In this context is also Advantageously provided that at least one of

Protective devices within the communication chain even with at least one other protection device - which in turn may also be part of another communication chain - communicatively connected outside the communication chain via a communication interface, which particular priorities of the protection devices in terms of the order of opening and closing their circuit breakers especially can be set flexibly.

According to a further embodiment of the protection system according to the invention, the protection devices are additionally communicatively connected to each other by a common bus system. In particular, the bus system makes it possible to communicate centrally with the protection devices of the communication chain, in order, e.g. to change or access records stored on the storage devices. Furthermore, the bus system forms redundancy at e.g. Failure of a communication interface within the communication chain.

In this context, it is particularly advantageously provided that the bus system comprises a communication unit with a further communication interface. The further communication interface can be formed, for example, by a LAN, WLA, Bluetooth or infrared interface. The communication unit is set up with various external devices, eg computers or mobile phones, in particular Smartphones, communicate. In particular, external devices of an electricity provider can communicate with the further communication interface and in this way in particular influence which microswitches are to be opened and / or closed under which conditions.

The inventive method according to claim 17 for controlling a protection system according to the invention described above, in which the protective devices are communicatively connected in series by the communication interfaces and thereby form a communication chain whose protective devices are connected in parallel to a common power line comprises the method steps

Defining a maximum permissible current value for the first protection device,

Calculating a maximum permissible current value for each of the remaining protective devices as a function of the maximum permissible current value of the protective device preceding each other in the communication chain, and

Opening the microswitch of each of the other protective devices for which the maximum permissible current value is negative.

The common power line can be supplied, for example, by the power grid of an electricity supplier with alternating current. Furthermore, however, a decentralized generator power, such as three-phase current, in the Feed power line. Furthermore, direct current generated by, for example, photovoltaic systems or provided by battery storage can also flow in the power line.

The setting of the maximum permissible current value for the first protective device can, for example, take place in such a way that it is stored as a value range on the memory unit of the first protective device, the value range detecting all values which are greater than the maximum permissible current value. The microswitch of the first protection device can be controlled by its control unit e.g. be opened when current values generated by the current measuring unit of the first protection device in the aforementioned range of values. The maximum permissible current value of the second protective device is preferably calculated as a function of the maximum permissible current value for the first protective device in the control unit of the first protective device. The calculation of the maximum permissible current value for the other protection devices - if available - is analogous to the calculation for the second protection device.

On the memory unit, a value range is stored, which includes negative maximum permissible current values. A negative maximum permissible current value for a protection device means that more current is already flowing through the preceding protection devices in the communication chain than specified by the maximum permissible current value for the first protection device. In this Case, the microswitch of the relevant protection device is opened, whereby a circuit connected to the protective device is disconnected from the power line. The maximum permissible current value for all subsequent protection devices is also negative, so that their microswitches are also opened. The

Method is particularly well suited to give the first protection device a maximum power consumption priority, which decreases for each additional protection device and is the lowest for the last protection device.

The inventive method can be particularly simple, effective and clear circuits of protective devices separated from the power line.

A first embodiment of the inventive method according to claim 17 is advantageously characterized by calculating the maximum permissible current value for each of the remaining protection devices by measuring a current strength and generating a current value representing the measured current value by the current measuring units of the first to the second last protection device in the communication chain, generating a current value representing the measured current value, subtracting the current value generated in a respective protection device from the maximum allowable current value for the respective protection device by means of the control unit of the respective protection device and transmitting the difference value to the respective subsequent protection device in the communication chain via the communication chain. The maximum permissible current value for the second protection device in the control unit of the first protection device is calculated as the difference between the maximum permissible current value defined for the first protection device and one by the current measurement unit of the first protection device

Calculated protection device and transmitted to the second protection device via the communication chain. The maximum permissible current value for the third protection device, if present, is calculated in the control unit of the second protection device from the difference between the maximum permissible current value calculated for the second protection device and a current value generated by the current measurement unit of the second protection device and to the third protection device transmitted via the communication chain. The calculation of the maximum permissible current values for the other protection devices - if present - and the transmission of the difference values is done analogously.

In other words, the maximum current that can be measured in a protective device without its control unit opening the microswitch is limited to the value of the maximum permissible current value for the first protective device minus the sum of the currents measured in the preceding protective devices of the communication chain. The maximum permissible current value thus assumes the highest value for the first protection device and the lowest value for the last protection device. The current values generated by the current measurement units are preferably the last ones in each case the respective current measuring unit generated current value, which represents the current measured by the current measuring unit current. The first embodiment enables a particularly current, simple and effective way of coordinating the opening of micro-switches or an associated separation of

Circuits from the power line.

Preferably, the maximum permissible current value is determined taking into account the design of the common power line or the amount of current that can be provided in it. If, for example, the current in the common power line is limited by a fuse, then the maximum permissible current value is preferably smaller than the value of the triggering current strength of the fuse. This is particularly advantageous because in particular can be prevented by opening a sufficient number of micro-switches that the fuse of the common power line must trigger. The fuse is only redundancy in the event that a microswitch does not open in time.

Furthermore, the maximum permissible current value can be set such that it does not exceed an available current in the power line, which can be specified for example by a user or externally by an electricity supplier eg via the common power line. Thus, a user of the protection system is allowed to the current flowing through the circuits of the protection devices total power limit and thus particularly easy to save electricity. Among other things, the opportunity arises for a power provider to be able to respond more flexibly to fluctuations in the availability of electricity in his supply network by correspondingly adjusting the maximum permissible current value for the first protection device and thereby also for the entire protection system.

According to a further embodiment of the method according to claim 17 is advantageously provided the

Measuring a current intensity and generating a current value representing the measured current value by the current measuring unit of the last protective device in the communication chain,

Subtracting the current value generated in the last protection device from the maximum permissible current value for the last protection device by means of the control unit of the last protection device and

Transmission of the difference value to the other protection devices via the communication chain.

According to this embodiment, in the last

Protective device calculates a difference value and transmitted to the other protection devices, which indicates how much power may flow at most additionally in the protection devices without at least one micro-switch is disconnected. In this context, it is particularly advantageously provided that the calculation of the maximum permissible current values for the second to last protective device, calculating the difference value in the last protection device and transmitting the difference value to all other protection devices within the period of a current flowing in the common power line current, whereby a particularly rapid coordination of the opening of ikroschaltern is enabled. Even if a direct current flows in the common power line, correspondingly high-frequency current measurements can likewise be carried out, for example, by stipulating corresponding time values in the protective devices.

A further advantageous embodiment is characterized by storing a current value, which was last generated by the current measuring unit of a protective device, before the microswitch was opened, on the storage unit of the protective device and closing the opened microswitch, if a maximum permissible current value calculated after opening for the

Protective device is higher than the stored current value.

Even after opening a circuit breaker of a protective device, maximum permissible current values for the protective device are still calculated. If the maximum allowable current value is less than the stored current value measured last before the microswitch has been opened, then the microswitch will remain open. Instead, the microswitch would be closed again and, what is at least probable, the same or approximately the same current measured in the circuit, so the control unit would immediately reopen the microswitch, because a current value generated after closing the microswitch would exceed the maximum permissible current value for the protection device and the latter would become negative. This could lead to an unstable operating state of the protection system, in which the microswitch would be continuously opened and closed. Therefore, the microswitch is not closed again until a maximum permissible current value calculated for the relevant protective device is at least as high as the stored current value. This embodiment contributes to the fact that an opened microswitch closes again after a particularly short time, and thus a current circuit which is separated from the common power line is again supplied with power particularly quickly, without causing unstable operating states of the protection system.

The inventive method according to claim 23 for controlling a protection system according to the invention described above, in which the protective devices are communicatively connected in series by the communication interfaces and thereby form a communication chain and the protective devices are connected in parallel to a common power line, the- includes steps

Setting a maximum permissible current value, setting a maximum opening value for each protective device, Calculating remaining maximum permissible current values in each case depending on a sum of in each case one current value of all protective devices,

Opening the microswitch of a protective device, if residual maximum permissible current values are continuously negative for longer than the maximum opening value of the protective device.

The maximum permissible current value can be set, for example, by depositing a corresponding value on at least one of the memory units of the protection devices, preferably on the memory unit of the first or last protection device in the communication chain. The opening maximum values are preferably set by storing a corresponding value on each of the storage units of the protective devices. The calculation of the remaining maximum permissible current values takes place in such a way that in each case a current value of each protective device is added several times in succession. If the current value sums formed thereby exceed the maximum allowable current value without interruption longer than the open maximum value for a protection device, then the microswitch of the protection device is opened, disconnecting a circuit connected to the protection device from the common power line.

According to the inventive method according to claim 23, each protection device in the communication chain can be assigned an arbitrary switch-off priority by the opening maximum value for the protection device is selected to be correspondingly high. The maximum opening value for a protection device determines how long one after the other the maximum permissible current values must be negative before the microswitch of the

Protective device is opened. Protective devices for which a lower open maximum value is set accordingly open faster than protective devices for which a higher open maximum value is set. The opening maximum values are preferably chosen shorter than the duration within which a fuse would initiate the power line.

According to a first advantageous embodiment, it is advantageously provided to set a maximum closing duration value for each protective device and to close an open microswitch of a protective device if the maximum permissible current values calculated after opening the microswitch are continuously positive for longer than the closing maximum value defined for the protective device.

By setting the maximum closure values, the protection devices can be assigned to restart protection priorities by: - if the maximum permissible current values calculated after opening the microswitch are continuously positive again - protective devices for which a lower maximum closure value has been set ^; de, shut down their open microswitch more quickly than protective devices, for which a higher Closing maximum value has been set. Particularly preferably, a combination of switch-on and switch-on priorities is provided in order to produce a particularly clear and unambiguous overall priority of the protective devices. For this purpose, higher open and lower maximum closure values are specified for protective devices to which a higher overall priority is to be assigned, than for protection devices with a lower one

Total priority should be assigned.

A further advantageous embodiment of the inventive method according to claim 23 is characterized by

Forming the sums of each of a current value of all protection devices by serially adding up in each case a current current value of all protection devices and calculating the remaining maximum allowable current values by subtracting the respective sum formed from the specified maximum allowable current value.

Serial adding means the following: The current measuring unit of the first protection device generates a current value and transmits it to the second protection device. The current measuring unit of the second protection device generates a current value, adds it to the current value transmitted by the first protection device and transmits the sum to the third protection device. The third and each additional protection device - if present - acts like the second protection device. In the electricity Values are the current, preferably the last generated by the current measurement units current values, which represent the current, preferably last measured by the current measurement units current values. The above-described steps are repeated, whereby the sums of each of a current value of all protection devices are formed. The sums formed are each deducted from the maximum permissible current value, resulting in the remaining maximum permissible current values. The adding and subtracting is preferably carried out by the control units of the respective protection devices.

It is also advantageous to transmit the remaining maximum permissible current values to all other protective devices via the communication chain, which has the particular advantage that the transmitted remaining maximum permissible current values can be transmitted to all protection devices particularly quickly and to decide on opening and / or of

Closing a microswitch are available. In this context, it is particularly advantageously provided that the calculation of a residual maximum permissible current value and its transmission to all other protective devices takes place within a period of a current flowing in the common power line, whereby a particularly fast vote on the opening and / or closing of micro-switches of Protective devices within the communication chain is possible. Even if in the common power line a DC current flows, for example, by setting appropriate time values in the protection devices also correspondingly high-frequency current measurements can be made.

Furthermore, for controlling a protection system according to the invention described above, in which a common circuit with one each

Output of multiple protection devices and one power line is connected to one input of the protection devices, the following steps are advantageously provided:

Defining a maximum opening value for each protection device,

Determining the opening state of the microswitch of each protection device and transmitting the determined opening state to all others

Protective devices as well

Opening of the microswitch of each protection device, if open states transmitted to it are continuously longer than the maximum opening value specified for it, that apart from its microswitch, at least one of the remaining microswitches is still closed.

By opening all but one

Circuit breaker can be made possible that at the same time only one of the microswitches of all protection devices is closed, so that the common circuit is connected to at least one load exclusively with one of the power lines. Under opening condition fall in particular those states in which the microswitch is open or closed or should be closed. Which of the power lines to remain connected to the circuit can be controlled in particular by setting different long opening maximum values.

The individual power lines can each be powered by its own power source, including u.a. the individual phases of a multi-phase current, e.g. a three-phase current, or various other current sources, e.g. DC currents of photovoltaic or battery storage, or AC of a central power supply network include. In each case an output of the

Protection devices are connected to a common circuit. In each protection device, the opening state of the microswitch is detected and can be applied to all other protection devices, e.g. be transmitted via the communication interfaces and / or via the common bus system. The described determination and transmission is preferably repeated permanently.

If, for example, a protective device whose microswitch is closed receives the information in this way that the microswitch of at least one other protective device should be closed, it will open its microswitch by means of its control unit, unless it has been opened for the duration of the opening opening defined for it. Maximum duration value, which starts to run after receiving the information, for example receives new information, according to which none of the remaining micro-switches should be opened.

Further, for controlling a protection system according to the invention described above in which a common circuit, each having an output of multiple protective devices and a respective power line, in each of which a phase of a multi-phase current flows, is connected to one input of the protection devices, the following steps can be advantageously provided :

Opening the microswitch of each protection device,

Determining the readiness of each protection device to close its microswitch, and transmitting the determined readiness to all other protection devices as well

simultaneously closing the microswitch of each protection device when the information has been transmitted to each protection device that the remaining protection devices are ready to close their microswitches.

This makes it possible, in particular, to close the microswitches of all protective devices at the same time or approximately simultaneously, whereby the circuit connected in common to the outputs of the protective devices can be fed simultaneously with all phases of the multiphase current. This is particularly advantageous, for example, for starting and operating a polyphase electric motor, which can be arranged in the electric circuit. The investigator The readiness of a protective device to close its microswitch can be effected, for example, by means of an impedance measurement unit described above and within the period of the polyphase current whose individual phases flow in the individual power lines. If said readiness was determined by each protection device and transmitted to all other protection devices, the control units of all protection devices whose microswitches are closed simultaneously.

Embodiments of the invention will ^be: explained with reference to the drawing. Hereby shows:

1 shows the schematic structure of an embodiment of a protection device according to the invention,

2 shows the schematic structure of an embodiment of a protection system according to the invention, whose protective devices are connected on the input side with a common power line and on the output side, each with a single circuit, and

Fig. 3 shows the schematic structure of another embodiment of a protection system according to the invention, the protective devices on the input side, each with its own power line and the output side are connected to a common circuit.

The exemplary embodiment of a protective device 1 according to the invention shown by FIG. 1 comprises a microswitch 2, which is connected in series with a fuse 3, a memory unit 4, a current measuring unit 5 and a control unit 6. Instead of the fuse 3, the protective device 1 alternatively also comprise a circuit breaker, not shown. Furthermore, the protective device 1 comprises an input 7 for connection to a current-carrying power line and an output 8 for connection to a circuit with at least one electrical load.

The current measuring unit 5 can measure through its current sensor 5 _S currents between the microswitch 2 and the output 8 and generate current values which represent measured currents and can be processed by the control unit 6. Two current value ranges are stored on the memory unit 4, namely a long-term overcurrent value range, which defines a long-term overcurrent state, and a short-circuit current value range, which defines a short-circuit state. Furthermore, a long-term maximum overcurrent value value assigned to the long-term overcurrent value range and a short-circuit current maximum duration value assigned to the short-circuit current value range are stored on the memory unit 4. The control unit 6 is set up, if one of the current measuring unit 5 generated in one or both of the two aforementioned ranges of values, the microswitch 2 by appropriate commands to open without the fuse 3 triggers. The control unit 6 is also set up to automatically close the microswitch 2 again, so that after a long-term overcurrent state or a short-circuit state no replacement or replacement of the fuse 3 is required.

Furthermore, a long-term excess-current maximum value associated with the long-term overcurrent value range and a short-circuit maximum value assigned to the short-circuit value range are stored on the memory unit 4. The control unit 6 can, according to another operating mode, then open the microswitch 2 if it recognizes by comparison that current values generated by the current measuring unit 5 for a duration longer than the long-term maximum maximum current value and / or the short-circuit maximum duration value in the Long-term overcurrent value range and / or short-circuit value range are.

The protective device 1 further comprises a temperature measuring unit 9, which has a temperature sensor 9 _S in the immediate vicinity of the fuse 3, so that they are temperatures in the vicinity of the wire. 3

Inside the fuse 3 and generate a temperature reading representing the measured temperature. can. On the storage unit 4, an over-temperature value range, which defines an over-temperature state of the wire 3 _{W of} the fuse 3, and an over-temperature maximum value associated with the over-temperature value range are stored.

The control unit 6 may according to a further mode of operation open the microswitch 2 when it detects by comparison that current values generated in the long-term overcurrent value range and for a duration longer than the long-term maximum overcurrent maximum value by the current measuring unit 5 a duration longer than the maximum overtemperature value by the temperature measuring unit 9 generated temperature measured values are in the excess temperature value range.

Furthermore, the protective device 1 comprises further measuring units in the form of a frequency 10, a voltage 11, and a power measuring unit 12, as well as an integrated into the power measuring unit 12 energy measuring unit and an integrated into the current measuring unit 5 impedance measuring unit , The further measuring units 9-12 are set up to measure frequencies, voltages, powers, energies or impedances in the protective device 1, and the frequency, voltage, power energy or the measured frequencies, voltages, powers, energies or impedances, respectively. Impedance to produce measured values. On the memory unit 4 corresponding value ranges are deposited, which are a type of the respective further measuring unit frequency and an undervoltage value range defining an abnormally low frequency state, an over-power and an over-consumption value range each defining a state of excessive power consumption and a high-impedance value range, respectively State defined in which loads in the circuit of the protection device are considered ready for shutdown. Furthermore, a respective maximum maximum value assigned to the said further value ranges is stored on the memory unit 4.

According to another mode of the protection device according to the invention whose control unit 6 opens the micro-switch 2, if

for a duration longer than the overflow maximum duration value stored on the storage unit, current values generated by the current measuring unit 5 are in the overcurrent value range stored on the storage unit (1st opening criterion) and for a duration longer than one of the further ones

Maximum duration values produced by the corresponding further measuring unit 9-12 lie in the further value range assigned to the further maximum duration value (second opening criterion).

According to yet another mode, the control unit 6 is adapted to the microswitch 2 open even if only the 2nd Öffnungskri- ¹ terium 2 is met.

According to another operating mode, the control unit 6 is further configured to generate and store an energy consumption value on the storage unit 4, which contains the energy consumption of a circuit connectable to the output 8 during a consumption period stored on the storage unit 4. For this purpose, the control unit 6 cumulatively adds the power measured values generated by the power measurement unit 12 during the consumption period. According to yet another mode of operation, the control unit 6 is configured to generate an energy consumption value for different loads in the circuit by evaluating a load profile and store it on the memory unit 4.

The protective device 1 also has a power supply unit 13 for the power supply of the protective device 1, which can be fed either by the connectable to the input 7 power grid or another power source. Furthermore, the protection device 1 comprises a communication interface 14 for wireless data transmission. The communication interface 14 allows not shown external communication interfaces with certain IP addresses to access the measured values generated in the protection device 1. However, access to the energy consumption values stored on the storage unit 4 is only possible through the input a definable by the user of the protection device 1 username and password possible, which in particular a power provider has no access to the energy consumption values.

The protection system 15 according to FIG. 2 comprises four protection devices 1A-1D, which are similar in each case to the protection device 1 shown by FIG. 1. Each protection device 1A-1D is connected at its input 7A-7D to a common power line in the form of an AC-conducting network 16, which carries an alternating current provided by a central electricity provider. Each protection device 1A-1D is further connected at its output 8A-8D to its own circuit 17A-17D with a plurality of consumers, not shown. The protection devices 1A-1D are communicatively connected with each other in series via communication ports 18-23 wirelessly communicating with each other, thereby forming a communication chain. For this purpose, the protection devices 1A, 1D at the end of the communication chain each comprise a communication interface 18, 23 and the remaining protection devices 1B, IC each have two communication interfaces 19-22. The protective devices 1A-1D are furthermore communicatively connected to one another via a common bus system 24 which comprises a communication unit 25 with a further communication interface 26.

In the following, the control or the operation of the protection system 15 shown by FIG. guide examples of the inventive method explained. The network 16 has a network fuse 27 which triggers upon reaching a tripping current. The value of the trigger current is stored permanently on the memory unit 4A of the first protection device 1D.

According to an operating mode of the protection system 15, the stored current value determines the maximum permissible current value for the first protection device 1A, from which the control unit 6A of the first protection device 1A deducts the current value determined last by its current measurement unit 5A represents a last measured by the current measuring unit 5A current between the microswitch 2A and the output 8A of the first protective device 1A. The difference value corresponds to the maximum permissible current value for the second protection device 1B, which is connected to the second

Protective device 1B is transmitted in the communication chain. The transmission takes place by means of two communicatively communicating communication interfaces 18, 19 of the first protection device 1A or of the second protection device IB.

The control unit 6B of the second protection device 1B subtracts from the obtained maximum allowable current value for the second protection device 1B the current value last determined by its current measurement unit 5B, the current value last measured by the current measurement unit 5B between the microswitch 2B and the output 8B of the second protection device 1B. The diffe- limit value corresponds to the maximum permissible current value for the third protection device IC which is connected to the third

Protective device IC is transmitted in the communication chain by means of two communicatively communicating communication interfaces 20, 21 of the second protection device 1B and the third protection device IC. The calculation of the maximum permissible current value for the fourth protection device 1D and its transmission to the fourth protection device 1D takes place in a manner analogous to that in the second protection device IB.

The control unit 6D of the fourth protection device 1D subtracts from the obtained maximum permissible current value for the fourth protection device 1D the current value determined last by its current measurement unit 5D, the current value last measured by the current measurement unit 5D between the microswitch 2D and the output 8D of the fourth protection device 1D. The difference value corresponds to a remaining maximum permissible current value for the protection system 15 and is transmitted via the communication chain to all other protection devices 1A-1C.

By this way of determining the maximum permissible current value for the protection devices 1A-1D, the first protection element 1A receives the highest priority with regard to the possible current decrease. The priority decreases from protection device to protection device within the communication chain and is the lowest for the fourth protection device 1D. The respective control units 6B- 6D of the second to last protection device 1B-1D opens its microswitch 2B-2D when the maximum allowable current value for the relevant protection device 1B-1D is negative. The control unit 6A of the first protection device 1A opens its microswitch 2A when the difference value formed in the first protection device 1A is negative.

A process cycle which comprises the calculation of the maximum permissible current value for all protective devices 1A-1D and the transmission of the remaining maximum permissible current value for the protection system 15 to all other protective devices 1A-1C takes place within a period of the alternating current flowing in the network 16. A completely continuous process cycle is followed directly by the next one

Process cycle, so that in each period of the alternating current flowing in the network is decided by the control units 6A-6D of the protective devices 1A-1D, whether a micro-switch 2A-2D is opened.

The closing of a previously opened microswitch 2A-2D is effected by storing the last current value generated by the current measuring unit 5A-5D of the relevant protective device 1A-1D before opening the microswitch 2A-2D on the memory unit 4A-4D of the protective device 1A-1D, and the microswitch 2A-2D is closed again when a currently available maximum permissible current value for the protective device 1A-1D calculated after opening the microswitch 2A-2D is greater than the stored current value. According to another operating mode of the protection system 15, a maximum permissible current value is determined by the value of the tripping current intensity of the network fuse 27 stored on the memory unit 4A of the first protection device 1A. From the maximum permissible current value, the sum of one current value of all protective devices 1A-1D is subtracted.

For this purpose, the control unit 6A of the first protection device 1A draws the last current measurement unit 5A of the first from the maximum permissible current value

Protective device 1A determined current value. The formed difference value is transmitted to the second protection device 1B in the communication chain. The control unit 6B of the second protection device 1B subtracts from the difference value obtained the current value last determined by the current measurement unit 5B of the second protection device 1B. The difference value formed is transmitted to the third protection device IC, in which a difference value is formed analogously to the second protection device 1B and transmitted to the fourth protection device 1D. The fourth protection device 1D subtracts from the difference value obtained the current value last determined by its current measurement unit 5D. The difference value formed corresponds to a residual maximum permissible current value for the protection system 15, which is transmitted via the communication chain to the first three protection devices 1A-1C. A process cycle which comprises the difference value formations in all protective devices 1A-1D and the transmission of the remaining maximum permissible current value to the first three protective devices 1A-1C takes place within the period of the alternating current flowing in the network 16. A complete process cycle is immediately followed by the next process cycle, so that each protection device 1A-1D receives the remaining maximum allowable current value in each period of the alternating current flowing in the network 16.

On the storage units 4A-4D of all protective devices 1A-1D, an opening maximum value is further stored in each case. If the remaining maximum permissible current values transmitted via the communication chain are continuously negative for a longer time than the maximum opening value of a protective device 1A-1D, then their control unit 6A-6D opens the microswitch 2A-2D. Thus, the protection device 6A-6D, on the memory unit 4A-4D of which the highest opening maximum value is stored, receives the highest priority with regard to the possible current decrease and the protection device 1A-1D, on whose memory unit 4A-4D the lowest maximum opening value is stored is the lowest priority.

The further exemplary embodiment of a protection system 15 according to the invention shown by FIG. 3 comprises the first three protection devices already shown in FIG. te 17A-17C, which form a communication chain by a total of four communication interfaces 18-21 in the manner already explained. The protective devices 1A-1C are also communicatively connected to one another via a common bus system 24 having a communication unit 25, which comprises a further communication interface 26. At the three inputs 7A-7C of the

Protective devices 1A-1C are each connected to a power line 16A-16C of a three-phase generator (not shown), each of the power lines 16A-16C leading a phase of the three-phase current. The three outputs 8A-8C of the protective devices 1A-1C are connected to a common circuit 17A which contains a plurality of loads, not shown.

According to an operating mode of the protection system 15 shown by FIG. 3, it is provided that all but one microswitch are opened. For this purpose, the storage units 8A-8C of the protective devices 1A-1C each have an opening maximum duration value which is the highest for the first protection device 1A, for the second protection device 1B lower than for the first protection device 1A and for the third protection device IC lowest ,

Within the period in the respective

Power line 16A-16C guided phase determine the micro-switches 2A-2C their opening state and transmit it immediately via the common bus 24 to all other protection devices 1A-1C. Alternatively or in addition the transmission can also take place via the communication chain. Thus, each protection device 1A-1C is informed within the period of the three-phase current which microswitches 2A-2C are open or closed.

For example, when the microswitches 2A, 2B of the first protection device 1A and the second protection device 1B are closed, the control unit 6B of the second protection device 1B will open the microswitch 2B thereof when the obtained information on the opening states is longer than the maximum opening value for the first second protection device 1B stops. The control unit 6A of the first protection device 1A will not open its microswitch 2A because the opening maximum value for the first protection device 1A is higher than for the second protection device 1B and thus no other protection device 1B, IC after opening the proximity switch 2B of the second protection device 1B besides the first protection device 1A, more has a closed microswitch 2B, 2C.

According to another mode of operation of the protection system 15 shown by FIG. 3, it is provided that all the microswitches 2A-2C are opened and resumed at the same time

getting closed. This operating mode lends itself when, for example, a three-phase electric motor (not shown) is to be started and operated in the electric circuit 17A. The closing of the micro-switches 2A-2C, after it has been determined in each protection device 1A-1C that their micro-switches 2A-2C are ready to turn on and the corresponding information has been provided to all other 1A-1C protection devices by transmission.

Claims

claims

1. Circuit Protection Device (1) (17A-17D)

full

one with a fuse (3) or one

Circuit breaker connected in series

Microswitch (2),

a current measuring unit (5),

a memory unit (4) and

a control unit (6),

in which

at least one current value range is deposited on the memory unit (4), the current measuring unit (5) is set up to measure current strengths in the protective device (1) and to generate the current values representing current values which the control unit (6) has set up for this purpose is to process the current values, the

Microswitch (2) to open when a current value is in the current value range and close the micro-switch (2) after opening.

2. Protection device (1) according to claim 1 characterized

marked that

at least one maximum duration value assigned to the at least one current value range is stored on the memory unit (4), and the control unit (6) is arranged to open the microswitch (2) when current values are longer than the maximum duration value in the current value range.

3. Protection device (1) according to claim 1 or 2, characterized in that the protective device (1)

at least one further measuring unit (9-12) from one

Temperature measuring unit (9),

Voltage measuring unit (11),

Energy measuring unit

Impedance measuring unit,

Frequency measuring unit (10) and

Includes performance measuring unit (12), wherein

at least one further value range corresponding to the type of the respective further measuring unit (9-12) is deposited on the memory unit (4),

-. the further measuring unit (9-12)

is set up to perform appropriate measurements of their type and to generate corresponding measured values and

the control unit (6) is set up to process the measured values and to open the microswitch (2) if a measured value lies in one of the further value ranges.

4. Protection device (1) according to claim 3, characterized

marked that

at least one further maximum duration value associated with the at least one further value range is stored on the memory unit (4), and

the control unit (6) is arranged to open the microswitch (2) if measured values are longer than the respective further maximum duration value in the respective further value range.

5. Protection device (1) according to one of the preceding

Claims, characterized in that at least one of the value ranges a state of a

Long term overcurrent condition,

Short circuit condition,

Over-temperature condition,

Undervoltage condition,

High impedance state,

Underfrequency state and

Condition of excessive power consumption or excessive energy consumption

Are defined .

6. Protection device (1) according to one of the preceding

Claims, characterized in that the

Value ranges and maximum duration values are editable.

7. Protection device (1) according to any one of claims 2 to 6, characterized in that the control unit (6) by processing by the energy measuring unit (12) generated energy measurements is adapted to a stored on the memory unit (4) To generate an energy consumption report which includes power consumption in the circuit (17A-17D) during a determinable period of time.

8. Protection device (1) according to claim 7, characterized

characterized in that the control unit (6) is arranged to distinguish between different loads consuming energy in the circuit (17A-17D) and one

Create energy consumption report for each individual load.

9. Protection device (1) according to one of the preceding

Claims, characterized in that the

Protective device (1) comprises at least one communication interface (14, 18-23).

10. Protection device (1) according to claim 9, characterized

characterized in that the communication interface (14, 18-23) is adapted to communicate wirelessly.

11. Protection device (1) according to claim 9 or 10, characterized in that the communication Interface (14, 18-23) is arranged to provide access to the current values and / or readings.

12. Protection device (1) according to one of claims 9 to 11, characterized in that the communication interface (18-23) is adapted to

Deny access to the storage unit (4) at least partially.

13. Circuit protection system (15) comprising

A plurality of protective devices (1) according to any one of claims 9 to 12, wherein the protective devices (1) by

Communication interfaces communicative

connected to each other.

14. Protection system according to claim 13, characterized

characterized in that the protection devices (1A-1D) are communicatively connected in series by the communication interfaces (18-23), thereby forming a communication chain.

15. Protection system (15) according to claim 13 or 14,

characterized in that the protective devices (1A-1D) are additionally communicatively connected to each other by a common bus system (24).

16. Protection system (15) according to claim 15, characterized

characterized in that the bus system (24) a Communication unit (25) with a further communication interface (26).

17. A method for controlling a protection system (15) according to any one of claims 14 to 16, whose

Protective devices (1A-1D) are connected in parallel to a common power line (16), comprising the steps:

Setting a maximum permissible current value for the first protection device (1A),

Calculating a maximum permissible current value for each of the remaining protection devices (1B-1D) as a function of the maximum permissible current value of the preceding protection device (1A-1C) in the communication chain and

Opening of the breaker switch (2B-2D) of each of the remaining protection devices (1B-1D) for which the maximum allowable current value is negative.

18. The method according to claim 17, characterized by calculating the maximum permissible current value for each of the remaining protective devices (1B-1D) by means of

Measuring a current and generating a current value representing the measured current through the current measuring units of the first protection device (1A) to penultimate

Protective device (IC) in the communication chain, deducting the current value generated in a respective protection device (1A-1C) of the maximum permissible current value for the respective

Protective device (1A-1C) by means of

Control unit of the respective protection device (1A-1C) and

Transmission of the difference value to the respective subsequent protection device (1B-1D) in the

Communication chain over the

Communication chain.

19. The method according to claim 17 to 18, characterized

characterized in that the maximum allowable

Current value for the first protection device (1A) less than the value of the tripping current level

Fuse (27) of the common power line (16) or not greater than the value of one in the common power line (16) available

Amperage is.

20. The method according to any one of claims 17 to 19,

marked by

Measuring a current intensity and generating a current value representing the measured current value by the current measuring unit (5D) of the last protective device (1D) in the communication chain,

Subtracting the current value generated in the last protection device (1D) from the maximum permissible current value for the last protection device (1D) by means of the Control unit (6D) of the last

Protective device (1D) and

Transmission of the differential value to the other protection devices (1A-1C) via the

communication chain

A method according to claim 20, characterized

characterized in that calculating the maximum allowable current values for the second protection device (1B) to last protection device (1D), calculating the difference value in the last protection device (1D) and transmitting the difference value to all other protection devices (1A-1C) within the

Period of one in the common

Power line (16) flowing current takes place.

Method according to one of claims 17 to 21, characterized by

Saving a current value last by the current measuring unit (5A-5D) of a

Protective device (1A-1D) was generated before the microswitch (2A-2D) was opened on the memory unit (4A-4D) of

Protective device (1A-1D) and

Closing the opened microswitch (2A-2D) when a maximum allowable current value calculated after opening for the

Protective device (1A-1D) higher than the

stored current value is.

23. A method for controlling a protection system (15) according to any one of claims 14 to 16, whose

Protective devices (1A-1D) are connected in parallel to a common power line (16), with the steps:

Setting a maximum allowable current value,

Setting an open maximum value for each protection device (1A-1D),

Calculate remaining maximum allowable

Current values in each case depending on a sum of a respective current value of all protective devices (1A-1D),

Opening the Microswitch of a Protection Device (1A-1D) when the remaining maximum allowable current values are continuously longer than the maximum open value of the protection device (1A-1D).

24. The method according to claim 23, characterized by

Defining a maximum closing value for each protection device (1A-1D) and

Closing of an open microswitch (2A-2D) of a protective device (1A-1D), if the maximum permissible current values calculated after opening the microswitch are continuously positive longer than the maximum closing value specified for the protective device (1A-1D).

25. The method according to claim 23 or 24, characterized by

Forming the surams of each of a current value of each protection device (1A-1D) by serially adding up each current value of each protection device (1A-1D) and calculating the remaining maximum allowable current values by subtracting the respective formed sum from the specified maximum allowable current value.

26. The method according to any one of claims 23 to 25,

characterized by transmitting the remaining maximum allowable current values to all other protection devices (1A-1C) via the communication chain.

27. The method according to any one of claims 23 to 26

characterized in that the calculation of a remaining maximum permissible current value and its transmission to all other protective devices (1A-1C) takes place within a period of a current flowing in the common power line (16).