Device and method for identifying an assignment of phase connections of two electrical devices

Abstract

Method for identifying an assignment of phase connections (R, S, T) of at least two electrical devices (2a-2d) which are connected to one another via the same plurality of phase conductors (L1, L2, L3) of an electrical distribution network (22), comprising the steps of: i) detecting connection voltages (UR(t), Us(t), UT(t)) which are respectively present at the phase connections (R, S, T) of the at least two devices (2a-2d), ii) determining individual device-related phasor representations of the connection voltages (UR(t), Us(t), UT(t)) for each of the at least two electrical devices (2a-2d) and decomposing the phasor representations into their respective symmetrical components, iii) determining at least one symmetrical component of a group-based phasor representation by determining the phasor lengths of the respective corresponding symmetrical components of the individual device-related Phasor representations are combined using a combination rule,iv) Determining a phasor representation for conductor voltages (UL1(t), UL2(t), UL3(t)) of the phase conductors (L1, L2, L3) of the electrical distribution network (22) from a combination of the detected connection voltages (UR(t), Us(t), UT(t)), wherein for the determination, a phase connection (R, S, T) of a respective device (2a-2d) is taken into account, the connection voltage (UR(t), Us(t), UT(t)) of which is combined with a connection voltage (UR(t), Us(t), UT(t)) of the at least one other device (2a-2d) via the combination rule, v) Decomposing the phasor representation of the conductor voltages (UL1(t), UL2(t), UL3(t)) of the phase conductors (L1, L2, L3) into their symmetrical components and determining a phasor length for at least the symmetric component corresponding to the at least one symmetric component of the group-based phasor representation also determined in iii),vi) comparing the phasor length for at least the corresponding symmetrical component of the phasor representation of the line voltages (UL1(t), UL2(t), UL3(t)) with the phasor length determined in iii) for at least the corresponding symmetrical component of the phasor representation of the connection voltages (UR(t), Us(t), UT(t)), wherein a quantity characterizing a deviation is quantitatively determined, vii) repeating steps iii) to vi) with a different combination for the phase connections (R, S, T) of the at least two electrical devices (2a-2d) to calculate the line voltages (UL1(t), UL2(t), UL3(t)), viii) identifying the assignment of phase connections (R, S, T) of the at least two electrical devices (2a-2d) that are connected to one another via the same phase conductor (L1, L2, L3), by determining the combination between the phase connections (R, S, T) of at least two electrical devices (2a-2d),where the quantity characterizing the deviation is minimal.,

Description

Technical field of the invention

[0001] The application relates to a method for identifying the assignment of phase connections of at least two electrical devices that are electrically connected to each other via the same phase conductor of a multi-phase AC voltage network. The application further relates to a device configured to carry out the method. State of the art

[0002] Electrical energy is transported from energy generation units to energy consumers via a comprehensive energy supply network. The energy supply network is designed as an alternating current network, particularly a multi-phase alternating current network, in which energy is transported via several phase conductors – usually two or three phase conductors – and a neutral conductor. An additional earth potential conductor is usually provided for protection purposes. A consumer unit, e.g., a building or a factory, can contain a multitude of electrical devices connected to a locally limited area of the energy supply network (hereinafter also referred to as the electrical distribution network), which in turn is connected to the rest of the higher-level energy supply network via a network connection point.

[0003] In order to avoid overloading individual phase conductors at the expense of others, it is generally desirable that the power flow within the electrical distribution network, as well as within the energy supply network, is distributed as evenly as possible across the multiple phase conductors. This is achieved on the one hand by distributing single-phase devices as evenly as possible across the available phase conductors in relation to the total power of the devices when they are first connected to the electrical distribution network. Even with multi-phase devices, it is desirable to connect each phase terminal to the phase conductor for which it is intended. At the very least, knowledge is desired as to which of the phase terminals of the devices are connected to the same phase conductor, or in other words, which phase terminals of the devices are connected to one another via the same phase conductor.This is especially true if the multi-phase devices are deliberately intended to be operated under a predefined unbalanced load.

[0004] Although the individual phase conductors of the electrical distribution network can be marked with different colors to distinguish them, which can then be connected to the likewise marked phase terminals of the electrical devices. In reality, however, the use of the correct color coding cannot always be guaranteed. For example, when wiring the consumer unit, a phase conductor with the correct color is not available and a phase conductor with a different, but available, color is used instead. Therefore, in a consumer unit with several multi-phase electrical devices, it is often not possible to guarantee that each phase terminal of one device is also connected to the corresponding phase terminal of another device, where the color coding matches the marking of one device, via the same phase conductor.Specifically, it may happen, for example, that in the case of two three-phase electrical devices with phase connections R, S, T, the phase connection R of the first device is connected to the phase connection S of the second device via the same phase conductor, e.g. L1 of a three-phase distribution network. This can make proper operation of the consumer unit more difficult, particularly if a defined unbalanced load is to be set at a grid connection point of the consumer unit for the consumer unit as a whole, i.e. the majority of the electrical devices, and / or an existing unbalanced load within the distribution network is to be deliberately changed. Therefore, a method is desired which, in the case of several electrical devices, each with several phase connections, reliably identifies the assignment of those phase connections that are each connected to one another via the same phase conductor of the electrical distribution network.

[0005] EP 2 204 658 A1 discloses a multi-phase electrical power distribution network comprising a substation, a signal generator, and a signal discriminator. The signal generator provides a different signal on each of a plurality of phases leaving the substation. The signal discriminator serves to detect each of the different signals at an electrical energy consumer. By providing the different signal on each of the phases, their identification can be ensured. However, this requires a separate signal generator.

[0006] The publication WO 2020 / 064 169 A1 describes a method for identifying the assignment of phase lines of an electrical distribution network to terminals of an unbalanced load capable electrical device that is connected to multiple phase lines of the electrical distribution network. In the method, target parameters assigned to an unbalanced load profile are set at the terminals of the electrical device. A measurement parameter, particularly in the form of a time profile, is detected at each of the phase lines. The detected measurement parameters are compared with the target parameters of the unbalanced load profile. Based on the comparison, the assignment of the phase lines to the respective terminals of the device is then identified. Although this does not require a separate signal generator, an electrical device capable of unbalanced load is required.The procedure cannot be applied to multi-phase devices that cannot be operated with unbalanced loads.

[0007] The (not yet published) application DE 10 2021 119 207 A1 discloses a method for identifying an assignment of phase terminals (R, S, T) of an electrical device to the respective connected phase conductors of an electrical distribution network. In the method, voltage fluctuations are detected on each of the phase conductors of the electrical distribution network, on the one hand, and on the phase terminals of each of the devices, on the other. The phase terminals are assigned to the respective connected phase conductors by comparing the detected voltage fluctuations. However, since voltage fluctuations can change rapidly over time, it is necessary that their detection is carried out as synchronously as possible at all points. However, this cannot be guaranteed for electrical devices that are not synchronized or are only insufficiently synchronized with each other.Rather, voltage fluctuations in the phase conductors that occur at the same time are given different time stamps, which suggests to an evaluation unit that the voltage fluctuations occur at a different time.

[0008] The publication DE 10 2018 107 423 A1 discloses a method for assigning phases in a multiphase alternating current low-voltage network feeder with multiple multiphase connection points, in which measured values of an electrical measured quantity of the individual phases of a first and the individual phases of a second of the multiple multiphase connection points are received. For multiple possible candidate phase assignments of the individual phases of the first multiphase connection point to the individual phases of the second multiphase connection point, a value for a correlation measure is determined depending on the received measured values. Depending on the determined values for the correlation measure, a candidate phase assignment is selected from the multiple candidate phase assignments.

[0009] WO 2013 / 025836 A1 discloses a method for determining the phase relationship between power meters. This involves collecting clock-stamped messages transmitted between nodes in a network containing at least two power meters. The messages contain zero-crossing measurements of a power signal acquired at a corresponding power meter. The clock-stamped messages are used to determine the relative timing between the clocks within the power meters. The relative phases between the power meters are determined based on the relative timing and the zero-crossing measurements.

[0010] The document US 2003 / 0 169 029 A1 discloses a method for identifying a phase of a cable in a three-phase power distribution network. In the power distribution network, a first measuring device is connected to a first cable at a first point and a second measuring device is connected to a second cable at a second point. The first and second measuring devices are synchronized with each other so that a start time is identical for each measuring device. The first measuring device measures a first interval in which a voltage on the first cable passes through a predetermined voltage in a predetermined direction. The second measuring device measures a second interval in which a voltage on the second cable passes through the predetermined voltage in the predetermined direction. The phase of the second cable is calculated in response to the first and second intervals.

[0011] Document AT 514 768 A1 discloses a method and device for measuring electrical quantities in three-phase systems. The phase voltages and currents are recorded for the three phases, and the corresponding voltage and current signals are evaluated in processing means to produce measured value data. The processing means determines the relative phase positions of the voltage signals and current signals in comparison to a predetermined phase sequence, and from this, the correctness or incorrectness of the connections of the voltage and current sensors to the phase conductors. Object of the invention

[0012] The invention is based on the object of providing a method for identifying the assignment of phase connections of at least two electrical devices that are connected to each other via the same phase conductor of a multi-phase AC voltage network. It is also an object of the invention to provide a device suitable for implementing the method. Solution

[0013] The object of specifying a method of the type mentioned above is achieved by a method having the features of independent claim 1. The object of specifying a device for carrying out the method is achieved by a subject matter having the features of independent claim 13. Advantageous embodiments of the method are recited in claims 2 to 12, and an advantageous embodiment of the device is recited in claim 14. Description of the invention

[0014] A method according to the invention for identifying an assignment of phase connections of at least two electrical devices that are connected to one another via the same multiple phase conductors of an electrical distribution network comprises the following steps: i) Detection of connection voltages applied to the phase connections of at least two devices, ii) determining individual device-related phasor representations of the connection voltages for each of the at least two electrical devices, decomposing the phasor representations into their respective symmetrical components, iii) determining at least one symmetrical component of a group-based phasor representation by combining phasor lengths of the respective corresponding symmetrical components of the individual device-related phasor representations for the at least two devices using a combination rule, iv) Determining a phasor representation for conductor voltages of the phase conductors of the electrical distribution network from a combination of the recorded connection voltages, whereby for the determination one phase connection of each device is taken into account, the connection voltage (U R (t), U S (t), U T (t)) is combined with a connection voltage of at least one other device via the combination rule, v) decomposing the phasor representation of the conductor voltages of the phase conductors into their symmetrical components and determining a phasor length for at least the symmetrical component that corresponds to the at least one symmetrical component of the group-based phasor representation also determined in iii), vi) comparing the phasor length for at least the corresponding symmetrical component of the phasor representation of the line voltages with the phasor length determined in iii) for at least the corresponding symmetrical component of the phasor representation of the connection voltages, whereby a deviation characterising quantity is determined quantitatively, vii) repeating steps iii) to vi) with a different combination for the phase connections of the at least two electrical devices to calculate the phase voltages, viii) identifying the assignment of phase terminals of the at least two electrical devices which are connected to one another via the same phase conductor by determining the combination between the phase terminals of the at least two electrical devices at which the quantity characterising the deviation is minimal.

[0015] The electrical device can be a device that is designed to generate a unidirectional power flow from the distribution grid towards the device during its operation, i.e. to operate as an energy consumer with respect to the distribution grid. For this purpose, the device can be connected to an energy sink or comprise such a sink. Alternatively, it is also possible for the device to be designed to generate a unidirectional power flow from the device towards the distribution grid during its operation, i.e. to operate as an energy generator with respect to the distribution grid. For this purpose, the device can be connected to an energy source or comprise an energy source. Additionally, it is also possible for the device to be designed to generate a bidirectional power flow between the distribution grid and the device during its operation.In this case, the device can operate as an energy consumer in relation to the distribution grid during one period and as an energy producer during another. For this purpose, the device can be connected to or contain an energy storage device, such as a rechargeable battery.

[0016] AC voltage quantities on the various phase conductors of an AC network are also referred to as a multi-phase system. The AC voltage quantities on the various phases usually have sinusoidal waveforms of the same frequency, which, at least in a three-phase multi-phase system, have a phase difference of, for example, 120° between them. The phase difference represents the angular difference between the sinusoidal waveforms. In the phasor representation of the AC voltage quantities, the sine curves are represented by phasors, i.e., vectors with phasor length and direction. The phasor length can correspond to an amplitude or an effective value of the AC voltage quantity. The phasor for each phase of the AC network has one end at a fixed zero point, the so-called origin point.The angles of the phasors relative to each other correspond to the phase difference between the phases of the AC voltage network.

[0017] The method of symmetric components takes advantage of the fact that any asymmetric system of phasors can be divided into several symmetric subsystems, its so-called symmetric components. An asymmetric system of phasors is understood to be a system whose phasors differ in their phasor length and / or their included angle. The asymmetrically loaded multi-phase system results from a superposition of the several symmetric subsystems. Without loss of generality, the following explanation is based on a three-phase system with a total of three phasors. In the three-phase system, the division occurs into a symmetric positive-sequence system, a negative-sequence system, and a zero-sequence system. The positive-sequence system and the negative-sequence system each have a phasor for each phase. The zero-sequence system has a common phasor for all three phases.The phasor lengths in the positive sequence system are the same for all phases, and thus for all phasors in a multi-phase system. In the case of three phases, neighboring phasors form an angle of 120° with each other. The phasor lengths in the negative sequence system are also the same for all phases of a multi-phase system, and the included angle of neighboring phasors is also 120° in a three-phase system. However, the direction of rotation of the phasors in the negative sequence system is opposite to the orientation of the phasors in the positive sequence system. Thus, while the phasors are oriented clockwise in the positive sequence system, they are oriented counterclockwise in the negative sequence system. Using the method of symmetric components, a simplified analysis can be carried out for asymmetric multi-phase systems, usually three-phase systems, using the symmetric subsystems consisting of positive sequence system, negative sequence system, and zero sequence system.

[0018] Determining the individual device-specific phasor representations of the supply voltages includes, at a minimum, determining the corresponding phasor lengths for each of the supply voltages, e.g., their amplitudes. The phasor angles for the individual device-specific phasor representations can, but do not necessarily have to, be determined from the supply voltage measurements. In many cases, for three-phase AC networks, the angles between the phasors can be assumed to be 120° without having to tolerate large errors.

[0019] In this case, group-based representation of the at least one symmetrical component is understood to mean a representation of the at least one symmetrical component related to the at least two devices. For this purpose, the phasor representation of its connection voltages is first determined for each of the at least two devices. The phasor representation is then broken down separately for each device into its respective symmetrical components: positive sequence system, negative sequence system, and zero sequence system. The phasor lengths of the at least one corresponding symmetrical component are then combined for the at least two devices using the combination rule. By corresponding symmetrical components, we mean that, for example, positive sequence system is combined with positive sequence system and / or negative sequence system with negative sequence system and / or zero sequence system with zero sequence system.

[0020] The combination rule can be, in particular, a calculation of the arithmetic mean, an addition or subtraction, or similar. Specifically, in the group-based phasor representation, for example, an averaging • the phasor lengths of the individual device-related positive-sequence systems • the phasor lengths of the individual device-related negative systems, and / or • the phasor lengths of the individual device-related zero systems take place.

[0021] By averaging the phasor lengths of the individual device-related negative sequence systems, one then obtains the phasor length of the negative sequence system of the group-based phasor representation, and so on. In this case, the combination rule corresponds to an average. However, instead of averaging, one can also sum each of the results. In this case, the combination rule would be a summation.

[0022] In step iv), the same combination rule is used to calculate the line voltages as in step iii). Therefore, if the group-based phasor representation in step iii) is performed using the averaging described above, the line voltage in step iv) is also calculated by averaging the respective terminal voltages. However, if addition was used as the combination rule for the group-based phasor representation in step iii), the line voltage in step iv) is also calculated by adding the respective terminal voltages.

[0023] When determining the phasor representation for conductor voltages of the phase conductors of the electrical distribution network from the combination of the recorded connection voltages, a phase connection of a respective device is taken into account for the determination, the connection voltage of which is combined with a connection voltage of at least one other device using the combination rule. The connection voltages at the connections of a respective device correspond to a multi-phase system with an associated phasor representation. In the phasor representation of the connection voltages of the respective devices, the phasor for a respective connection of a first of the at least two devices is combined with the respective phasor of the respective corresponding connection of the at least one other device using the combination rule.

[0024] In this context, the phase-to-phase voltage is a virtual calculation value that may or may not be identical to the actual voltage on a phase conductor of the electrical distribution network. The phase-to-phase voltage may or may not be derived from the actual voltage on a phase conductor of the electrical distribution network.

[0025] The phasor representation of the line voltages of the phase conductors is then decomposed into its symmetrical components, and the phasor length for at least one corresponding symmetrical component is determined. The corresponding symmetrical component corresponds to the symmetrical component used in step iii). If, for example, the positive sequence system was used in step iii), the positive sequence system is also used here. If, for example, the negative sequence system was used in step iii), the negative sequence system is also used here. If, for example, the zero sequence system was used in step iii), the zero sequence system is also used here.

[0026] By comparing the phasor lengths determined in step iii) with those determined in step v), a deviation of the phasor lengths from each other can be determined and a quantity characterizing the deviation is quantitatively determined.

[0027] Steps iii) to vi) are repeated with a different combination, i.e. assignment to one another, i.e. at least one different assignment for the phase connections of the at least two electrical devices for calculating the conductor voltages. All possible combinations, i.e. assignments of connections of the at least two devices, can thus be taken into account. If it is certain that the correct assignment has been found before all assignments have been checked, the process can be terminated prematurely without having to examine all possible further assignments. This can be the case, for example, if the variable characterizing the deviation is below a certain predefinable threshold value or is even zero.

[0028] Then, the assignment of phase terminals of the at least two electrical devices that are connected to each other via the same phase conductor is identified by determining the combination between the phase terminals of the at least two electrical devices at which the quantity characterizing the deviation is minimal.

[0029] In particular, the method can be used to identify which phase terminals of a large number of devices are connected to the same phase conductor. The method can be implemented simply and cost-effectively. Furthermore, the method can be applied even when the measurements required for the method are not synchronous to one another, but rather have a time offset. The use of phasor representations and the associated decomposition into symmetrical components makes the method more robust.

[0030] The method detects an unbalanced load or asymmetry in the electrical distribution grid, the extent of which is unknown in particular. The method offers the advantage that the assignment of a phase conductor to a phase connection can be determined based on an unbalanced load that already exists in the electrical distribution grid. The already existing asymmetry or unbalanced load arises from the normal operation of a group of energy consumers, energy producers and / or energy storage devices that are connected to the various phase conductors of the distribution grid and / or the associated energy supply grid. Specifically, the asymmetry is caused by an asymmetric power exchange, i.e. the unbalanced load, between the group of energy consumers, energy producers and / or energy storage devices and the respective phase conductors of the electrical distribution grid.The asymmetry or unbalanced load that is already present on the phase conductors usually receives no special attention, is often even undesirable, but cannot be completely avoided. The invention, however, takes advantage of the fact that the unbalanced load that is already present usually varies from phase conductor to phase conductor and therefore forms a characteristic marking for each phase conductor, which can be detected via the phasor representation. The individually different asymmetries or unbalanced loads therefore make the phase conductors distinguishable from one another. The unbalanced loads that are already present are also transferred in their respective form to the phase connections of the device connected to the phase conductors. By using the phasor representations and the associated decomposition into symmetrical components, this effect is advantageously utilized.Specifically, an asymmetry or unbalanced load manifests itself as a non-zero negative sequence system and / or a non-zero zero sequence system. In other words, whenever a non-zero negative sequence system and / or a non-zero zero sequence system is present, this characterizes an unbalanced load in the electrical distribution grid.

[0031] Once an unbalanced load exists in the electrical distribution grid, it is a more temporally constant property of the electrical distribution grid, which changes only relatively slowly—at least compared to voltage fluctuations within the phase conductors, as used, for example, in the method of the as yet unpublished application DE 10 2021 119 207. It can be caused by a larger number of single-phase energy consumers or single-phase energy generators connected to one phase conductor in the distribution grid relative to the other phase conductors. Once these are connected, i.e., connected to their respective phase conductors, an asymmetrical power exchange associated with the connection configuration also persists for a longer period of time.Finally, once the devices are connected to their assigned phase conductors, they are not disconnected again without reason and reconnected to the phase conductors in a different connection configuration. Specifically, an unbalanced load, once it has existed, exhibits at least significantly lower dynamics than is the case with the aforementioned voltage fluctuations of the phase conductors. Therefore, in this method, a time offset in the recording of the connection voltages of at least two electrical devices plays a significantly smaller role than in the method of DE 10 2021 119 207. In other words, the method described here places lower demands on the temporal synchronization of the at least two electrical devices than is the case with the method of DE 10 2021 119 207.

[0032] In one embodiment of the method, the number of phase connections for one, several, or each of the at least two electrical devices is identical to the number of phase conductors of the distribution network. In a preferred embodiment, the number of phase conductors of the distribution network and the number of phase connections of the devices are each three.

[0033] In one embodiment of the method, a first of the at least two electrical devices, optionally also a second or each of the at least two electrical devices, has a neutral conductor connection. The distribution network also has a neutral conductor, which is connected to the neutral conductor connection of the first device, optionally also to the neutral conductor connection of the second or to the neutral conductor connection of each of the at least two electrical devices. The method can thus also be applied to AC systems with a neutral conductor. In AC systems without a neutral conductor, an autotransformer can optionally be provided. The neutral conductor connections of the devices can each be connected to a center point connection of the autotransformer.

[0034] The method is capable of identifying the assignment of the phase connections to the respective connected phase conductors by means of a measurement of the connection voltages of the at least two electrical devices assigned to a single point in time. In one embodiment of the method, however, method steps i) - viii) are each carried out taking into account the time profiles of the connection voltages on the one hand and the conductor voltages determined therefrom on the other. Method steps i) - viii) are repeated at time intervals. The variable characterizing the deviation is determined in accordance with the time profile of the deviation. For example, a single variable characterizing the deviation can be continuously updated over time.By using time profiles of the voltages, an even more precise identification of the assignment of the phase connections can be achieved compared to using the voltages at a specific point in time.

[0035] In one embodiment of the method, the at least two electrical devices are part of a group of devices which has a plurality n, with n>2, of electrical devices. The n electrical devices in the group are jointly connected to the electrical distribution network. Here, the identification of the assignment of the phase connections can be carried out in such a way that for each device in the group there are one or two further devices in the group with an identified assignment of the corresponding phase connections. One device in the group can be designated as the reference device. The identification of the assignment of the phase connections of the further devices in the group can then be carried out in relation to the phase connections of the reference device. This is advantageous, for example, if the assignment of the phase connections to the respective phase conductors has already been identified by the reference device and is therefore known.Alternatively, it is often sufficient to simply know which phase connections of the devices are connected to each other via the same phase conductor, regardless of which phase conductor (L1, L2, or L3) is involved. Therefore, it is also possible to define the assignment of its phase connections to the associated phase conductors for the reference device, and thus to name the phase conductors of the electrical distribution network for the purpose of identifying the assignment of the other devices.

[0036] For a group of n devices, the method can be implemented by considering all combinations of the connections of the n devices. However, for larger numbers n, the computational effort increases significantly. On the other hand, calculations can be performed (n-1) times for different groups of two devices. This reduces the computational effort.

[0037] For some electrical devices, proper operation requires a measuring unit for determining the connection voltages, which is then already present in the electrical device. In embodiments, the connection voltages at the phase connections of one, several, or each electrical device can therefore be measured using a measuring unit present in the respective device. In such an embodiment, a measuring unit already present in the respective device can also be used for the method, so that no additional effort is required in this regard.

[0038] In embodiments, the phasor length in step v) is determined from at least two of the symmetrical components: positive sequence system, negative sequence system, and / or zero sequence system. Furthermore, the phasor lengths in step iii) are each determined from at least two corresponding symmetrical components from the positive sequence system, negative sequence system, and / or zero sequence system and combined according to the combination rule. By using two symmetrical components, the quality of the identification of the assignment can be further improved compared to the use of only one symmetrical component. In particular, the positive sequence system can be used with one of the other two symmetrical components. The quantitative determination of the quantity characterizing the deviation can then be carried out as a function of phasor lengths using the corresponding negative sequence systems and positive sequence systems or the corresponding zero sequence systems and positive sequence systems.

[0039] In one embodiment, the quantitative determination of the quantity characterizing the deviation is carried out by calculating sums of squares of the errors.

[0040] In one embodiment, the values of the line voltages and / or the values of the connection voltages from one, several, or each of the electrical devices can be communicated to a server. At least part of the method can be carried out by an evaluation unit in the server. A server is a computer that provides computing capacity and / or other resources so that other computers or programs can access it via a network, e.g., the Internet. The described method can be distributed and run at least partially on the remote server. Alternatively, however, it is also conceivable for the values of the line voltages and / or the values of the connection voltages to be communicated from one, several, or each device to a selected device. In this case, the method can be carried out at least in part by an evaluation unit present in the selected device.

[0041] A device for identifying the assignment of phase connections of at least two electrical devices connected to one another via the same multiple phase conductors of an electrical distribution network comprises measuring units assigned to each of the at least two electrical devices. Each of the measuring units is designed to detect a connection voltage at each of the phase connections of the corresponding device. The device additionally comprises an evaluation unit. Furthermore, the device is designed and configured to carry out one or more of the previously described methods.

[0042] In one embodiment of the device, one, several or each of the devices has the measuring unit assigned to the respective device for detecting the connection voltages at the phase connections of the device.

[0043] The evaluation unit can be a component of one of the devices, several of the devices, and / or the server. The evaluation unit can thus be located in one or more of the devices or the server. The evaluation unit can also be implemented in a distributed manner and be partially located in one or more devices. The evaluation unit can also be located at least partially in the server.

[0044] The method makes it possible to identify those phase connections of a plurality of multi-phase electrical devices that are each connected to one another via the same phase conductor of the electrical distribution network. This eliminates the need to mark and / or modify the line voltages – and thus also the connection voltages of the device – in an identifiable manner using the device itself or a separate signal generator. Rather, the method exploits the fact that the phase conductors and thus also the associated phase connections of the electrical devices can be distinguished from one another via the unbalanced load already present in the electrical distribution network. To characterize the unbalanced load, a non-zero negative sequence system and / or a non-zero zero sequence system is used.

[0045] Advantageous embodiments of the invention are specified in the following description and the subclaims, the features of which can be used individually and in any combination with one another.

[0046] Various applications of the method and device are described below.

[0047] For example, an electrical system comprising a large number of multi-phase electrical devices connected to a common electrical distribution network may require unbalanced load limitation and / or overload protection. In order to implement this specifically for the group of electrical devices, it is necessary to know which of the phase connections of the electrical devices are connected to the same phase conductor of the electrical distribution network. For example, it may be necessary to reduce the power drawn at a specific phase conductor, which should ideally be distributed across several phase connections of the electrical devices connected to this phase conductor. Since the method can be used to identify exactly those phase connections of the electrical devices that are connected to one another via the same phase conductor, unbalanced load limitation and / or overload protection can be implemented specifically.In addition, the procedure can support balancing measures carried out by an energy supply network operator. Short description of the characters

[0048] The invention is illustrated below with the aid of figures, of which Fig. 1 shows a first embodiment of a device for identifying an assignment of phase connections of two electrical devices that are connected to each other via the same phase conductor; Fig. 2 shows a second embodiment of a device for identifying an assignment of phase connections of two electrical devices that are connected to each other via the same phase conductor; Fig. 3 A phasor representation of a measured connection voltage with its decomposition into positive sequence, negative sequence and zero sequence; Fig. 4 a flowchart of the method for identifying an assignment of phase connections of two electrical devices that are connected to each other via the same phase conductor, in one embodiment.

[0049] In the figures, identical or similar elements are designated by the same reference numerals. The representation in the figures is not necessarily to scale. Character description

[0050] In Fig. 1 shows a first embodiment of a device 1 for identifying an assignment of phase connections R, S, T of two electrical devices 2a, 2b.

[0051] The two electrical devices 2a, 2b are connected to each other via phase conductors L1, L2, L3 of a three-phase distribution network 22. Each of the devices 2a, 2b has three phase terminals R, S, T for connection to the three phases of the three-phase distribution network 22. Each of the devices has a neutral conductor terminal NG. Each of the two neutral conductor terminals NG is connected to a neutral conductor N of the distribution network 22.

[0052] In the example shown, terminal R of device 2a is connected to phase conductor L3. Terminal S of device 2a is connected to phase conductor L2. Terminal T of device 2a is connected to phase conductor L1. In the example shown, terminal R of device 2b is connected to phase conductor L2. Terminal S is connected to phase conductor L1. Terminal T of device 2b is connected to phase conductor L3.

[0053] The distribution network 22 is connected to an energy supply network 20 via a network connection point. The energy supply network 20 is a three-phase alternating voltage network.

[0054] Each of the terminals R, S, and T of a respective device 2a, 2b is therefore connected to a respective phase conductor L1, L2, and L3. The following procedure can be used to determine which of the terminals R, S, and T of device 2a is connected to the same phase conductor L1, L2, and L3 as a respective terminal of the other device 2b.

[0055] First, the connection voltages U R (t), U S (t), U T (t) of device 2a and device 2b. For each device 2a, 2b, the three alternating voltages U R (t), U S (t), U T(t) a multi-phase system. The multi-phase system for each device 2a, 2b is described in a respective phasor representation. Due to the three-phase design of the distribution network 22 and the three phase connections of the devices 2a, 2b, each of the two individual device-related phasor representations also contains three phasors. Each of the two individual device-related phasor representations is decomposed into its symmetrical components: positive sequence system, negative sequence system, and zero sequence system. A group-based phasor representation is then determined for at least one of the symmetrical components. To determine at least one symmetrical component of the group-based phasor representation, the phasor lengths of at least one of the symmetrical components of both devices 2a, 2b are combined using a combination rule, for example, averaging. Specifically, for example, an average value can be determined from the phasor lengths of both negative sequence systems of the devices 2a, 2b.

[0056] In addition, phase conductor voltages U L1 (t), U L2 (t), U L3 (t) is determined by measuring the connection voltages U R (t), U S (t), U T (t) for device 2a and device 2b - and thus also the phasor representations of the respective connection voltages U R (t), U S (t), U T (t) for device 2a and device 2b - are combined using the combination rule. Specifically, each of the connection voltages U R (t), U S (t), U T (t) of the device 2a with one of the connection voltages U R (t), U S (t), U T(t) of device 2b. Not only is a combination of identically named phase terminals R, S, T of both devices 2a, 2b permitted, in which terminal R of device 2a is combined with terminal R of device 2b, terminal S of device 2a is combined with terminal S of device 2b, and terminal T of device 2a is combined with terminal T of device 2b. Rather, unlike-named combinations are also deliberately permitted, in which, for example, terminal S of device 2a is combined with terminal R of device 2b, terminal T of device 2a is combined with terminal S of device 2b, and terminal R of device 2a is combined with terminal T of device 2b. This then results in a phasor representation for the line voltages U L1 (t), U L2 (t), U L3 (t). The phase voltages U L1 (t), U L2 (t), U L3(t) also represent a multi-phase system. The phasor lengths of the phasor representation of the line voltages U L1 (t), U L2 (t), U L3 (t), however, differ in most cases from those of the individual device-specific phasor representations due to the combination rule. The phasor representation of the line voltages U L1 (t), U L2 (t), U L3(t) is then decomposed into its symmetrical components: positive sequence system, negative sequence system, and zero sequence system. The phasor lengths of this decomposition or the phasor length of a component of this decomposition are then compared with the phasor lengths or the phasor length previously determined for the corresponding symmetrical components of the group-related phasor representations. From this comparison, a deviation is determined, and a quantity characterizing the deviation is quantitatively determined, for example, using a least-squares method. A very small characterizing quantity is an indication that the currently examined combination of terminals R, S, T of the two devices 2a, 2b is connected to the same phase conductor L1, L2, L3.

[0057] The conductor voltages U L1 (t), U L2 (t), U L3(t) are in this context a virtual calculation quantity that can be identical to the real voltages on the phase conductors L1, L2, L3 of the electrical distribution network 22, but does not have to be. The phase voltages U L1 (t), U L2 (t), U L3 (t) may be derived from the respective real voltages on the phase conductors L1, L2, L3 of the electrical distribution network 22, but do not have to be.

[0058] These steps can be repeated for another combination or combinations of phase terminals R, S, T between device 2a and device 2b. The combination for which the value characterizing the deviation is smallest is then the combination of phase terminals R, S, T of device 2a and device 2b that are connected to the same phase conductor L1, L2, L3. Thus, the phase terminals R, S, T of devices 2a and 2b that are connected to each other via the same phase conductor L1, L2, L3 can be identified.

[0059] The device 2a is designed, for example, as a bidirectionally operating battery inverter, which feeds electrical energy from a battery 3 into the distribution network 22 or draws it from the distribution network 22. The device 2b is designed, for example, as a photovoltaic inverter, which feeds electrical energy from a photovoltaic generator 4 (photovoltaic PV) into the distribution network 22. An evaluation unit 11 has a data connection and / or control connection 14 with the measuring units 13, which in Fig. 1 is symbolized by a dashed line. The evaluation unit 11 can be configured to carry out the steps of the previously described method in whole or in part.

[0060] In Fig. Figure 2 shows a second embodiment of a device 1 for identifying the assignment of phase terminals R, S, T of electrical devices 2a to 2d that are connected to one another via the same phase conductor. In the illustrated embodiment, four electrical devices 2a, 2b, 2c, and 2d are shown.

[0061] The device 2a is a battery inverter operating bidirectionally with respect to its power flow, which connects the battery 3 to the distribution grid 22. The device 2b is a photovoltaic inverter, which connects the PV generator 4 to the distribution grid 22. The device 2c is a hybrid inverter, to whose DC voltage side both a battery 3 and a PV generator 4 are connected. The inverter 2c connects the battery and the PV generator to the distribution grid 22. Fig. 2 shows an AC / AC converter which connects a motor 5 to the distribution network 22. The electrical devices 2a, 2b, 2c have in common that they are designed and configured to feed electrical energy into the distribution network 22. However, at least for the devices 2a and 2c, a bidirectional power exchange between the distribution network 22 and the battery 2 connected to the device is also possible. The electrical device 2d can draw electrical energy from the distribution network 22 and transfer it to the motor 5. However, it can also be designed bidirectionally with regard to its power flow and, for example, feed the released energy into the distribution network 22 when the motor M is decelerated.

[0062] Via the grid connection point 21, it is also possible to feed electrical energy into the supply grid 20 and / or draw it from the supply grid 20. Devices 2a to 2c each have a radio interface 6 for communication. Device 2d is connected to device 2c via a data connection 14.

[0063] In the example shown, it is possible to determine the connection voltages U R (t), U S (t), U T (t) of devices 2a to 2d, measuring units already included in devices 2a to 2d shall be used. The recorded measurement data for the connection voltages U R (t), U S (t), U T(t) can then be transmitted, for example, via the respective radio interface 6 and, in the case of device 2d, via the data and control connection 14 and then via the radio interface 6 of device 2c. The evaluation unit can receive such a transmission via the radio interface 6. In this example, the evaluation unit 11 is located in a server 31, which is arranged remotely from the device 1. The data of the server 31 can be accessed via the Internet 30 using a computer 32 with a user interface. The connection of the server 31 to the devices 2a-2d of the device 1 can also be established via the Internet 30 and via the data and control connection 14, whereby the radio interface 6 can establish the connection of the devices 2a, 2b, 2c to the Internet 30.

[0064] The R terminal of device 2a is connected to the phase conductor L3. The phase terminal S of device 2a is connected to the phase conductor L2. The phase terminal T of device 2a is connected to the phase conductor L1 of the distribution network. In device 2b, the phase terminal R is connected to the phase conductor L2, the phase terminal S is connected to the phase conductor L1, and the phase terminal T is connected to the phase conductor L3. In device 2c, the phase terminal R is connected to the phase conductor L2, the phase terminal S is connected to the phase conductor L1, and the phase terminal T is connected to the phase conductor L3. In device 2d, the phase terminal R is connected to the phase conductor L3, the phase terminal S is connected to the phase conductor L2, and the phase terminal T is connected to the phase conductor L1. The neutral conductor terminals NG of devices 2a, 2b, 2c, and 2d are each connected to the neutral conductor N of the distribution network 22.

[0065] The method for identifying an assignment of phase terminals R, S, T of the devices shown in Figures 2a to 2d allows for the determination of those terminals of the respective devices that are connected via the same phase conductors L1 to L3. For this purpose, for example, the connection voltages U are measured for each of the devices 2a to 2d. R (t), U S (t), U T (t) via the respective measuring units 13 present in the devices (in Fig. 2 not explicitly shown). For each of the devices 2a to 2d, the three connection voltages U R (t), U S (t), U T(t) a multi-phase system, which can be represented in a phasor representation. The respective phasor representations for the terminals R, S, T of devices 2a to 2d are then decomposed into their symmetrical components. Each device is then compared with another device by combining the phasor lengths of at least one of the symmetrical components using the combination rule. Care must be taken to select the corresponding symmetrical component, for example, positive-sequence system with positive-sequence system, negative-sequence system with negative-sequence system, and / or zero-sequence system with zero-sequence system. Alternatively or additionally, the phasor lengths of the respective symmetrical component or more than one symmetrical component of all devices 2a to 2d can be combined using the combination rule.Here, too, the phasor lengths of the corresponding symmetric components are always combined using the combination rule. In other words, the phasor lengths of the positive-sequence systems, the phasor lengths of the negative-sequence systems, or the phasor lengths of the zero-sequence systems are always combined.

[0066] The resulting combination of the phasor lengths of the corresponding symmetrical component is now checked for any deviation from the following. For either the same two devices from devices 2a to 2d or - if all devices were previously combined - for all devices 2a to 2d - the line voltages U L1 (t), U L2 (t), U L3 (t). For this purpose, the connection voltages U R (t), U S (t), U T (t) - i.e. the phasor lengths of the phasor representations of the connection voltages U R (t), U S (t), U T(t) - are combined with each other using the same combination rule, resulting in a phasor representation of the line voltages with three phasors. For each phasor of the line voltage, a phase connection R, S, T is included in the combination for each of the devices 2a - 2d. The phasor length of each phasor for the line voltage is thus dependent on the selected combination of the connection voltages U R (t), U S (t), U T (t). This combination of the phasor representation is then decomposed into its symmetrical components, i.e., positive sequence, negative sequence, and zero sequence. The phasor length of the same corresponding symmetrical component, as described above, is now compared with the previously determined phasor length of the symmetrical component, which, as described above, is derived from the combination of the same symmetrical components of the terminal voltages U R (t), U S (t), U T(t) was determined. Using this comparison, a measure of a quantitative deviation is determined. If several symmetric components are to be compared, the above applies analogously to each of the symmetric components to be compared.

[0067] This process is repeated for various combinations of phase terminals R, S, and T of devices 2a to 2d. The combination with the smallest deviation is the combination in which the compared terminals R, S, and T are connected to the same phase conductors L1, L2, and L3.

[0068] In Fig. 3 is an example of a phasor representation of a multi-phase system (here: a three-phase system) from connection voltages U R (t), U S (t), U T (t). Below are examples of the voltages U resulting from the decomposition of the phasor representation of the terminal voltages R (t), U S (t), UT (t) resulting symmetric components. Specifically, the positive-sequence system U RM , U SM , U TM The starting point of each phasor lies at a common origin. The phasors of the counter-system U resulting from the decomposition also lie at the same point of origin. RG , U SG , U TG (in Fig. 3 (shown below center) have a common starting point. The respective phasor lengths in the positive sequence system are the same for all three phases. The respective phasor lengths in the negative sequence system are also the same for all phases. The zero sequence system (in Fig. 3 shown bottom right) has a single phasor U0. In the upper part of Fig. 3 also shows how the positive sequence system, negative sequence system and zero sequence system form the multi-phase system of the connection voltages U R (t), U S (t), U T(t). When moving from the phasor representation in the upper part of Fig. 3 to the symmetrical components positive sequence system, negative sequence system and zero sequence system in the lower range of Fig. 3 we speak of a decomposition of the phasor representation into its symmetric components.

[0069] In Fig. Figure 4 shows a schematic flow diagram of the method. The method is used to identify the assignment of phase connections between two electrical devices that are connected via the same phase conductor.

[0070] The process starts in step S1. In step S2, the connection voltages U R (t), U S (t), U T(t) for multiple devices. The devices can, for example, be devices assigned to a group. The devices can also be, for example, all devices 2a-2d connected to a distribution network 22. This sub-step of S2 corresponds to step i) described above. In step S2, the individual device-specific phasor representations are also determined and decomposed into the respective symmetrical components of positive-sequence system, negative-sequence system, and zero-sequence system. This sub-step corresponds to step ii) described above.

[0071] In step S3 a reference device is selected and in step S4 another device is selected.

[0072] In step S5, the phasor lengths are combined for, for example, the positive and negative sequence systems of the symmetrical components of the individual device-related phasor representations. Fig. The combination rule shown in Figure 3 is an example of an averaging, which can in particular be the formation of an arithmetic mean. Fig. In the example illustrated in Figure 3, step S5 is performed for the reference device and the currently selected device of all devices 2a-2d connected to the phase conductors L1, L2, L3 of a distribution network 22. This substep of S5 corresponds to step iii) described above.

[0073] In step S6, the combination of phase connections R, S, T of the currently selected device is selected in comparison with the reference device. In step S7, the phase voltages U are determined. L1 (t), U L2 (t), U L3 (t). The phase voltages U L1 (t), U L2 (t), U L3 (t) are determined in such a way that the respective phasor lengths of the connection voltages U R (t), U S (t), U T(t) are combined in a manner corresponding to the combination of the phase connections that occurred in step S6. This sub-step of S7 corresponds to the previously described step iv). Then, in the next sub-step of step S7, the phasor representation of the line voltages U L1 (t), U L2 (t), U L3 (t) is decomposed into its symmetric components, and the phasor lengths for the positive and negative sequence systems are determined. This substep of S7 corresponds to the previously described step v).

[0074] In step S8, the deviation of the phasor lengths for the selected combination of the phase connections (R, S, T) of the device is then compared to the phase connections (R, S, T) ref of the reference device. For this purpose, the phasor lengths for the positive and negative sequence phase voltages U L1 (t), U L2 (t), U L3(t) are compared with the phasor lengths of the averaged individual device-related symmetric components. This step S8 corresponds to the previously described step vi).

[0075] In step S9, a check is performed to determine whether all possible combinations of phase connections R, S, T between the device and the reference device have been compared. If this is not the case, the process from step S5 to step S9 is repeated. If, however, it is determined in step S9 that all combinations of phase connections R, S, T between the device and the reference device have been compared, a check is performed in step S10 to determine whether all devices in the group of devices 2a - 2d to be examined have been taken into account. If this is not the case, the process from step S4 to step S10 is repeated, but this time with a different device selected than before.

[0076] The result is output in step S11. Specifically, for each device in the group of devices 2a-2d to be analyzed, the identified assignment of phase terminals R, S, T to phase terminals R, S, T of the reference device, which are connected to each other via the same phase conductor L1, L2, L3, is output. This is equivalent to the assignment of the phase terminals R, S, T for each device in the group of devices 2a-2d to be analyzed to the phase conductors L1, L2, L3 of the distribution network 22. The method ends in step S12. List of reference symbols 1 device 2a, 2b, 2c, 2d Electrical device 3 Battery 4 Photovoltaic (PV) generator 5 Engine 6 radio interface 11 Evaluation unit 13 measuring unit 14 Data connection 20 Energy supply network 21 Grid connection point 22 Distribution network 30 Internet 31 servers 32 computers R, S, T phase connection NG neutral conductor connection L1, L2, L3 phase conductors N neutral conductor U L1 (t), U L2 (t), U L3 (t) Line voltage U R (t), U S (t), U T (t) Connection voltage S1-S12 process step

Claims

[1] Method for identifying an assignment of phase connections (R, S, T) of at least two electrical devices (2a-2d) which are connected to one another via the same one of several phase conductors (L1, L2, L3) of an electrical distribution network (22), comprising the steps: i) Recording of connection voltages (U R (t), Us(t), U T (t)), which are each connected to the phase terminals (R, S, T) of the at least two devices (2a-2d), ii) Determination of individual device-related phasor representations of the connection voltages (U R (t), Us(t), U T (t)) for each of the at least two electrical devices (2a-2d) and decomposing the phasor representations into their respective symmetrical components, iii) determining at least one symmetrical component of a group-based phasor representation by combining the phasor lengths of the respective corresponding symmetrical components of the individual device-related phasor representations for the at least two devices (2a-2d) by means of a combination rule, iv) Determine a phasor representation for line voltages (U L1 (t), U L2 (t), U L3 (t)) the phase conductors (L1, L2, L3) of the electrical distribution network (22) from a combination of the recorded connection voltages (U R (t), Us(t), U T (t)), whereby for the determination a phase connection (R,S,T) of a respective device (2a-2d) is taken into account, the connection voltage (U R (t), Us(t), U T (t)) with a connection voltage (U R (t), Us(t), U T (t)) of the at least one other device (2a-2d) is combined via the combination rule, v) Decomposition of the phasor representation of the line voltages (U L1 (t), U L2 (t), U L3 (t)) the phase conductors (L1, L2, L3) into their symmetrical components and determining a phasor length for at least the symmetrical component which corresponds to the at least one symmetrical component of the group-based phasor representation also determined in iii), vi) Comparison of the phasor length for at least the corresponding symmetrical component of the phasor representation of the line voltages (U L1 (t), U L2 (t), U L3 (t)) with the phasor length determined in iii) for at least the corresponding symmetrical component of the phasor representation of the terminal voltages (U R (t), Us(t), U T (t)), whereby a quantity characterising a deviation is determined quantitatively, vii) repeating steps iii) to vi) with a different combination for the phase connections (R, S, T) of the at least two electrical devices (2a-2d) to calculate the conductor voltages (U L1 (t), U L2 (t), U L3 (t)), viii) identifying the assignment of phase terminals (R, S, T) of the at least two electrical devices (2a-2d) which are connected to one another via the same phase conductor (L1, L2, L3), by determining the combination between the phase terminals (R, S, T) of the at least two electrical devices (2a-2d) at which the quantity characterising the deviation is minimal. [2] Method according to claim 1, wherein in one, several, or each of the at least two electrical devices (2a-2d) a number of phase connections (R, S, T) is identical to a number of phase conductors (L1, L2, L3) of the distribution network (22). [3] Method according to claim 1 or 2, wherein a first of the at least two electrical devices (2a - 2d), optionally also a second or each of the at least two electrical devices (2a - 2d), has a neutral conductor connection (NG) and the distribution network (22) has a neutral conductor (N) which is connected to the neutral conductor connection (NG) of the first, optionally also the second or each of the at least two electrical devices (2a - 2d). [4] Method according to one of the preceding claims, wherein the method steps i) - viii) are repeated after time intervals, whereby a consideration of time profiles of the connection voltages (U R (t), U S (t), U T (t)) on the one hand and the resulting conductor voltages (U L1 (t), U L2 (t), U L3 (t)) on the other hand. [5] Method according to one of the preceding claims, wherein the at least two electrical devices (2a-2d) are part of a group with a plurality n, with n>2, of electrical devices (2a-2d) which are jointly connected to the electrical distribution network (22). [6] Method according to claim 5, wherein the identification of the assignment of the phase terminals (R, S, T) is carried out such that for each device (2a-2d) of the group there are one or two further devices (2a-2d) of the group with an identified assignment of the corresponding phase terminals (R, S, T). [7] Method according to claim 5 or 6, wherein a device (2a) of the group is determined as a reference device, and wherein the identification of the assignment of the phase connections (R, S, T) of the further devices (2b-2d) of the group is carried out relative to the phase connections (R, S, T) of the reference device. [8] Method according to one of the preceding claims, wherein in one, several or each electrical device (2a-2d) the detection of the connection voltages (U R (t), Us(t), U T (t)) at the phase terminals (R, S, T) via a measuring unit (13) present in the respective device (2a-2d). [9] Method according to one of the preceding claims, wherein in step v) the phasor lengths of at least two of the symmetrical components positive sequence system, negative sequence system and / or zero sequence system are determined and wherein in step iii) the respective phasor lengths are determined from at least two corresponding symmetrical components of positive sequence system, negative sequence system and / or zero sequence system and are combined according to the combination rule. [10] Method according to claim 9, wherein the quantitative determination of the quantity characterizing the deviation is carried out as a function of phasor lengths of the corresponding negative and positive systems or of the corresponding zero and positive systems. [11] Method according to one of the preceding claims, wherein the quantitative determination of the quantity characterizing the deviation is carried out by means of a calculation of sums of squares of the errors. [12] Method according to one of the preceding claims, wherein values of the conductor voltages (U L1 (t), U L2 (t), U L3 (t)) and / or values of the connection voltages (U R (t), Us(t), U T (t)) are communicated to a server (31) and at least part of the method is carried out by an evaluation unit (11) in the server (31). [13] Device (1) for identifying an assignment of phase connections (R, S, T) of at least two electrical devices (2a-2d), which are each connected to one another via the same one of several phase conductors (L1, L2, L3) of an electrical distribution network (22), comprising: - measuring units (13) assigned to the at least two electrical devices (2a-2d) for detecting a connection voltage (U R (t), Us(t), U T (t)) at each of the phase terminals (R, S, T) of the corresponding devices (2a-2d), and - an evaluation unit (11), characterized by that the device (1) is designed and arranged to carry out the method according to one of the preceding claims. [14] Device (1) according to claim 13, wherein the evaluation unit (11) is a component of one of the devices (2a-2d), several of the devices (2a-2d) and / or the server (31).

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