Method for determining measurement variables in a mesh of a low-voltage network, mesh current controller, system and use of a mesh current controller

Abstract

The invention presents and describes a method (100) for determining measurement variables in a mesh (7) of a low-voltage network (1), wherein the method (100) comprises providing a mesh current controller (9) in a mesh (7) of a low-voltage network (1), wherein the mesh current controller (9) comprises a controllable current and / or voltage source (29). The method (100) furthermore comprises determining at least one measurement variable of the mesh (7) by way of the mesh current controller (9) using the current and / or voltage source (27). The invention further presents and describes a mesh current controller (9) for controlling a voltage in a mesh (7), wherein the mesh current controller (9) comprises a controllable current and / or voltage source (29) and is set up to carry out the method (100) described here independently. The invention also presents and describes a system (27) for determining measurement variables in a mesh (7) of a low-voltage network (1) and for controlling a voltage in the mesh (7), wherein the system (27) comprises a mesh current controller (9) having an ascertaining unit (29) for determining measurement variables in the mesh (7) at the mesh current controller (9). The invention lastly presents and describes the use of a mesh current controller (9) in a mesh (7) of a low-voltage network (1), wherein no measurement points for determining measurement variables for the mesh current controller (9) are used in the mesh (7) outside of the mesh current controller (9).

Description

[0001]Maschinenfabrik Reinhausen GmbH Method for determining measured variables in a mesh of a low-voltage network, mesh current controller, system and use of a mesh current controller The present invention relates to a method for determining measured variables in a mesh of a low-voltage network, a mesh current controller, a system and a use of a mesh current controller. Low-voltage networks, such as local grids, generally have three phases and are often implemented as a meshed structure in order to be able to supply any consumers of the low-voltage network via an alternative line. Consumers of a load connection in a low-voltage network can be, for example, single-family or multi-family homes or commercial establishments. A mesh in a low-voltage network was previously often supplied from the medium-voltage level via a central transformer.Centralized supply via a transformer was previously sufficient, as only consumers whose power consumption could be easily estimated were connected to a mesh. The increasing feed-in from solar systems or small wind turbines makes estimating power consumption significantly more difficult. Consumption is also difficult to predict, for example due to the increasing use of charging stations for electric vehicles. Therefore, overloads can occur at individual outlets within the mesh. To prevent these overloads, state-of-the-art mesh current controllers are used, which can gradually apply an additional voltage to the mesh using transformers. To regulate these transformers, measuring points within the mesh are required, so the known mesh current controllers cannot function without external measuring devices.State-of-the-art methods for determining power outflows within a mesh also have several decentralized measuring units within the mesh. In general, with meshed low-voltage networks it is desirable that measured variables in the mesh can be determined particularly easily, without the need for decentralized measuring units or measuring units distributed throughout the mesh, so that no extensive reconstruction measures are necessary within the mesh. 1 2022P00039 WO Maschinenfabrik Reinhausen GmbH In addition, with meshed low-voltage networks it is generally desirable to achieve a high level of supply security by controlling the power flows in the mesh in a particularly simple way, ideally without the need for extensive reconstruction measures within the mesh, such as the installation of decentralized ormeasuring units distributed throughout the mesh or large, heavy and expensive transformers. It is therefore an object of the present invention to provide a method and a mesh current controller with which measured variables in the mesh can be determined in a particularly simple manner, in particular without the need for decentralized or (additional) measuring units distributed throughout the mesh, so that in particular no extensive reconstruction measures within the mesh are necessary. Furthermore, the aim is in particular to make it possible to achieve the highest possible supply security of a low-voltage network, for example by being able to control the current flows in the mesh in an advantageously simple manner, preferably without the need for extensive reconstruction measures within the mesh. These objects are achieved by the features of the independent patent claims.Further advantageous embodiments of the solution proposed here are specified in the dependent patent claims. It should be noted that features listed individually in the dependent patent claims can be combined with one another in any technologically expedient manner and can define further embodiments of the invention. Furthermore, the features listed in the patent claims are further specified and explained in the description, wherein further preferred embodiments of the invention can also be presented. According to a first aspect of the invention, the stated object is achieved by a method having the features of patent claim 1. The method serves to determine measured variables in a mesh of a low-voltage network.The method comprises providing a mesh current controller in a mesh of a 2 2022P00039 WO Maschinenfabrik Reinhausen GmbH low-voltage network, wherein the mesh current controller has a controllable current or voltage source. Furthermore, the method comprises determining at least one measured variable of the mesh with the mesh current controller using the current or voltage source. The method is preferably carried out with a mesh current controller presented here or a system presented here. The method is used to determine measured variables in a mesh of a low-voltage network. The method advantageously enables measured variables within the mesh to be determined at different locations or areas within the mesh without explicitly requiring decentralized or separate measuring units at the different locations. Rather, this determination is carried out by the mesh current controller itself oras such. In other words, this can in particular also be described in such a way that the method serves to determine measured variables for or locations or areas of a mesh of a low-voltage network, wherein the locations or areas are spaced or spatially removed from the actual measuring entity, the (individual) mesh current controller provided according to the method. In particular, a determination unit of the mesh current controller can determine measured variables within the mesh that are present outside the determination unit in the mesh. The mesh current controller can in principle be arranged centrally or decentrally in relation to the mesh or a (power) coupling point of the transformer arranged between the medium-voltage line and the mesh into the mesh. The mesh current controller can be set up to determine measured variables for locations or areas of the mesh that are decentralized in relation to the mesh orthe mesh flow controller. This can be described as a decentralized determination of measured variables in a mesh. The term "decentralized" refers in particular to the locations or areas at which the measured variables are determined. However, the actual measurement is advantageously carried out (centrally) by the mesh flow controller. The determination can thus be carried out in particular in the form of an indirect determination (indirect measurement) by the mesh flow controller, whereby the determination / measurement of the mesh flow controller is particularly representative of measured variables at corresponding decentralized positions within the mesh. In other words, this means in particular that measured variables within the mesh can be determined with a single determination unit.This makes it possible to determine measured variables within the mesh without the need for decentralized, external and / or separate measuring units from the perspective of the determination unit. The method comprises providing a mesh current controller in a mesh of a low-voltage network. Typically, a single or exactly one mesh current controller is provided in a mesh. Providing is preferably understood to mean that the mesh current controller is installed or connected in the mesh. Providing the mesh current controller can therefore include installing, connecting, and commissioning the mesh current controller within the mesh. During installation, the mesh is usually first switched to black so that no current flows in the mesh.Connection usually involves disconnecting the mesh cables at a coupling point on the mesh current controller, with one end connected to an input of the mesh current controller and the other end connected to an output of the mesh current controller, so that the mesh current controller is preferably connected in series. For commissioning, the mesh is switched white again so that current flows through the mesh and the mesh current controller can be switched on. After commissioning, the mesh current controller is in operation so that the measured variables in the mesh can be determined and, preferably, a current in the mesh can be regulated by coupling a current or a voltage at the coupling point of the mesh current controller. The mesh current controller has a controllable current or voltage source. A voltage source is preferably used to couple a series voltage into a line of the mesh.Such voltage sources can also be referred to as DVRs (“digital voltage restorers”) or voltage regulators and are suitable for controlling the series voltage. This can also be referred to as longitudinal voltage injection. Such a voltage source can be used in a mesh for longitudinal voltage injection to control the current in the mesh, since longitudinal coupling of a voltage changes the current distribution in the mesh. This can also be referred to as UPFCs (“unified power flow controllers”). The advantage of a controllable voltage source is that the regulated voltage value can be set particularly easily, thus allowing for a high degree of flexibility in coupling in a specific current value. A current source is preferably used to supply a specific current value in a line of the mesh.The current value can be increased or decreased as needed. The advantage of the current source is that the current can be coupled in directly. The controllable current / or voltage source preferably has a power electronic circuit. The power electronic circuit is particularly suitable and / or configured to set a specific (desired or predeterminable) current or voltage difference in the mesh. The current or voltage difference is particularly intended to contribute to determining the at least one measured variable. Further preferably, the current / or voltage source (exclusively) has switching elements, such as transistors (power transistors, switching transistors, MOSFETs, IGBTs).The controllable current / or voltage source is particularly preferably designed to increase or reduce the amplitude of the voltage in the line (as needed) and / or to shift the phase of the voltage and / or to feed in harmonics with specific frequencies, phases and / or amplitudes, in particular such that the voltage in the line can be adjusted and / or the current flow in the line can be controlled. As already mentioned, the method comprises determining at least one measured variable of the mesh with the mesh current controller using the current / or voltage source. Several or a large number of measured variables can be determined during operation of the mesh current controller. The determination can be carried out repeatedly several times during operation of the mesh current controller. In particular, the determination can be carried out continuously or repeated at spaced-apart points in time.It is also conceivable that the method is carried out at predefined times during the course of a day, a week or a month or after predefined time periods. To determine a measured variable in the mesh, the current / or voltage source can preferably have a current and voltage measuring device. With the current and 5 2022P00039 WO Maschinenfabrik Reinhausen GmbH voltage measuring device, current and voltage values ​​​​present at the current / or voltage source can be determined. Determining at least one measured variable of the mesh with the mesh current controller using the current / or voltage source preferably comprises a (targeted) change in an input current or voltage value, so that various current and voltage values ​​can be determined with the current and voltage measuring devices. Based on the various current and voltage values, further measured variables within the mesh can preferably be determined.These measured variables preferably comprise values ​​for currents, voltages and / or impedances within the mesh. When determining impedances, it is particularly preferred to determine a real and imaginary part of the impedance separately. The measured variables can preferably be determined on all three phases (in particular simultaneously or at least partially in parallel). This has the advantage that the measured variables can be determined in a particularly time-efficient manner. More preferably, the measured variables can be determined on individual phases one after the other. This has the advantage that the measured variables can be determined particularly accurately. In summary, it can be stated that a method is provided with which measured variables in the mesh can be determined in a particularly simple manner, in particular without the need for decentralized or(Additional) measuring units distributed throughout the mesh are required, so that in particular no extensive reconstruction measures within the mesh are necessary. Furthermore, it is made possible in particular to achieve the highest possible supply security of a low-voltage network by controlling the current flows in the mesh in an advantageously simple manner, preferably without extensive reconstruction measures within the mesh being necessary. In one embodiment, the method comprises determining a loop impedance. In order to determine the loop impedance, the voltage source can preferably be operated as an AC voltage source in phase with the mains voltage of the mesh and in particular can be set such that a current of zero results at the coupling point of the mesh current controller.In addition to the injected voltage, which was set to result in a zero current, a first 6 2022P00039 WO Maschinenfabrik Reinhausen GmbH differential voltage can be applied by the voltage source. Initially, the first differential voltage can be applied as a positive voltage so that a first current value can be measured at the mesh current controller. Subsequently, the first differential voltage can be applied as a negative voltage, and finally the first current value can be measured again at the mesh current controller. This process can be repeated several times so that several first current values ​​can result. A first average current value can be calculated from the resulting several first current values. The loop impedance can be calculated from the quotient of the voltage and the average current value.In one embodiment, the method comprises determining at least one segment impedance, in particular as a function of the loop impedance. The mesh can be divided into a first segment and a second segment, wherein, for example, the first segment can form a path between the transformer and an input side of the mesh current regulator, and the second segment can form the path between the transformer and an output side of the mesh current regulator. The loop impedance can represent the sum of an impedance of the first segment, which can be referred to as the first segment impedance, and an impedance of the second segment, which can be referred to as the second segment impedance. To determine the first and second segment impedances, the voltage source can be regulated to zero volts. A mains voltage and a mains current of the low-voltage network can now be determined.A value for a target reactive current can then be specified for the mesh current controller. Once the mesh current controller has been adjusted to the target reactive current, the grid voltage and grid current of the low-voltage grid can be determined again, and a second differential grid voltage and a second differential grid current can be calculated from the determined values. Once the second differential grid voltage and the second differential grid current have been calculated, the target reactive current can be set back to zero. This process can be repeated several times, and an average value for the differential grid voltage and the differential grid current can be calculated from the resulting multiple differential grid voltages and differential grid currents.Using the measured variables determined, the first segment impedance can (now) be determined by multiplying the loop impedance by a 7 2022P00039 WO Maschinenfabrik Reinhausen GmbH quotient, which is calculated from the differential current and the target reactive current. The second segment impedance can be determined analogously to the first segment impedance or from the difference between the loop impedance and the first segment impedance. In one embodiment, the method comprises determining a transformer impedance. First, a total grid impedance can be determined from a quotient of determined mean values ​​of the differential grid voltage and the differential grid current, such as the quotient of the previously determined mean values ​​of the differential grid voltage and the differential grid current. The total grid impedance can (now) be used to determine a transformer impedance.For this purpose, a local segment parallel impedance can (initially) be determined from the parallel impedances of the first and second segment impedances. The transformer impedance can then be determined from the quotient of the total network impedance and the determined segment parallel impedance. In one embodiment, the method comprises determining a (virtual) location factor of a load connection connected in the mesh and determining at least one section factor as a function of the location factor and a segment impedance. From the previously determined measured variables, further characteristic values ​​can be determined, which can be used for the real-time calculation of the load situation in the mesh. The segments can be divided into sub-segments (virtually or computationally for the purpose of determination).In the present embodiment, the first segment and the second segment can each be divided into two (or more) sub-segments, for example a first sub-segment and a second sub-segment. The segments can be divided into the same number or a different number of sub-segments. The respective sub-segments can be of equal length or can be determined such that they have varying lengths. It can preferably be provided that the sub-segments have different lengths. On the one hand, the first sub-segments can differ in length from the second sub-segments. Alternatively or cumulatively, the first sub-segments of a plurality of first sub-segments and / or the second sub-segments of a plurality of second sub-segments can each have different lengths from one another.The sum of the respective sub-segments usually (always) results in the length of the respective segment. More preferably, the sub-segments can be selected variably, for example dependent or independent (preferably dependent) of the location or area of ​​a load connection. The sub-segments are particularly preferably selected such that at least one load connection is located in or on one of the sub-segments. Further particularly preferably, the sub-segments are selected such that there is (a maximum of) one load connection in or on each of the sub-segments. This can advantageously contribute to ensuring that the measured variables determined for the respective sub-segments can always be assigned to the maximum of one load connection that is located in the respective sub-segment. In an (alternative) embodiment, the segments are divided into more than two sub-segments.In practice, a division into 5 to 30 sub-segments can prove advantageous. This can help to ensure that a load can be allocated more precisely within one of the segments. In principle, it can be assumed that the more sub-segments a segment has, the more precisely a load can be allocated within the segment. However, as the number of sub-segments increases, the computational requirements for determining the measured variables within the mesh or sub-segments also generally increase, which is why dividing a segment into approximately ten sub-segments has proven particularly advantageous. In this context, it is advantageous to set the number of sub-segments in one or more segments (each) to a value between 5 and 20. As already mentioned, each of the segments can be divided into sub-segments, whereby the sum of the sub-segments of the respective segment usually results in the length of the respective segment.In other words, this can also be described as each sub-segment being assigned a virtual location factor, which can also be referred to as a relative proportion factor. The proportion factor can be specified by a value between zero and one that corresponds to the proportional, relative length of the segment (the relative length of the sub-segment). For example, a sub-segment with a proportion factor of 0.5 corresponds to half the length of the corresponding segment. The division of the segments into sub-segments can preferably depend on the actual length of the segment or be representative of it, whereby the number of sub-segments can increase with the length of the segment. For example, if a segment has a length of one kilometer, the segment can be divided into ten sub-segments, each 100 meters long.For correspondingly shorter segments, dividing the segment into fewer sub-areas may be sufficient or advantageous, with a sub-segment particularly preferably having a length of at least 50 meters. This has the advantage that it can be achieved that only one consumer with a particularly high power requirement is located in a sub-segment. A consumer with a particularly high power requirement can, for example, be several single-family or multi-family homes, each with several households. A consumer with a particularly high power requirement can also be a commercial enterprise, for example. A commercial enterprise generally has a higher power requirement than, for example, a single-family or multi-family home. Based on the location factors or proportion factors, a sub-segment impedance can (now) be determined. To do this, the respective proportion factor can be multiplied by the respective segment impedance of the respective segment.From the calculated sub-segment impedances, the path factor can now be calculated for each sub-segment. To do this, a sub-segment parallel impedance can be divided by the sub-segment impedance of the sub-segment to determine the path factor of a sub-segment. The path factor serves, in particular, as a dimensionless parameter to determine what proportion of a load current of a load connected in a sub-segment or at the respective virtual location, which can be defined by the location factor or the proportion factors, would naturally flow at the installation location of the mesh current controller, i.e., without influence from the mesh current controller itself. The path factors preferably remain the same with unchanged impedances.In the idealized case of a homogeneous line (line cross-section constant along its length), the location factor is essentially equivalent to the assumed (real) distance between the location defined by the location factor (e.g., a connection point of a consumer or an area in which a consumer is connected to the mesh) and the mesh current controller. To save the calculated values, they can preferably be stored in a table. A separate table can be stored for each segment, so that a first table can be created to enter values ​​for the first segment and a second table to enter values ​​for the second segment. The tables can each contain three columns, with a local load current, the location factor or proportion factor, and the section factor being stored in the three columns.When creating the table, the value zero can initially be saved for the local load current. This is because the method can advantageously identify and calculate load changes within the mesh without the actual load having to be known. This has the advantage that the method can be carried out without the need for initial parameterization. In one embodiment, the method comprises controlling a current setpoint of the controllable current / voltage source via two voltage vectors, one of the voltage vectors being in phase with the mains voltage and the other of the two voltage vectors being orthogonal to the first voltage vector. The current setpoint can be controlled using the two voltage vectors. One of the vectors can be in phase orin the same direction as the mains voltage, wherein preferably the output of an integrator or an integrator and proportional element determines the amplitude of this component based on the setpoint difference of the active current component of the setpoint (I or PI controller). The second vector can be orthogonal to the first and thus also to the mains voltage, wherein more preferably the output of an integrator or an integrator and proportional element regulates the amplitude of this component based on the setpoint difference of the reactive current component of the setpoint (I or PI controller). The resulting manipulated variable is usually a voltage that is transferred to the voltage source converter. This results here in particular from the vectorial addition of the two components. In one embodiment, the method comprises determining a natural coupling point current.As already mentioned, significant load changes or current coupling at the load connections can lead to a load increase or load decrease in the segments. In order to advantageously compensate for any load increases or load decreases, the method can advantageously be used to determine a load-compensating coupling point current setpoint. The coupling point current setpoint usually specifies a setpoint for a coupling point current. For this purpose, a change in a natural 11 2022P00039 WO Maschinenfabrik Reinhausen GmbH coupling point current can be determined. The natural coupling point current generally represents a current change that would occur at the coupling point of the mesh current controller due to a load change in the case of direct coupling without the influence of the mesh current controller.The natural coupling point current is calculated in particular by multiplying the regulated coupling point current of the mesh current controller by the quotient of the voltage value of the voltage source and the loop impedance. In one embodiment, the method comprises determining a line voltage difference as a function of the segment impedance and a natural coupling point current change. To determine the change in the natural coupling point current, which can also be referred to as the natural coupling point current change, the natural coupling point current can be determined at a first time and a second time. The natural coupling point current change can be determined from the difference between the two values. The line voltage change can be calculated by forming the product of the natural coupling point current change and the segment impedance.In one embodiment, the method comprises determining a transformer voltage change as a function of the connection voltage change and the line voltage difference. Preferably, a first connection voltage change at the two connection points of the segments can be determined by determining the voltage at the connection point of the first segment at the first time and the voltage at the connection point of the first segment at the second time. Analogously, a second connection voltage change at the connection point of the second segment can also preferably be determined. Based on the two connection voltage changes, a dominant load change can be determined. For this purpose, in particular, it is (initially) determined in which segment the load change occurred. This is preferably done using the following case distinction.If the consumption current across the coupling point from the first segment to the second segment becomes positive, a load drop in the second segment can be assumed when the first connection voltage change increases. If the first connection voltage change decreases, a load increase in the first segment can be assumed. If the consumption current across the coupling point from the first segment to the second segment becomes negative, a load drop in the first segment can be assumed when the second connection voltage change increases. If the second connection voltage change decreases, a load increase in the second segment can be assumed. The transformer voltage change results in particular from the difference between the connection voltage change and the line voltage difference. Based on this determination, a compensating current can (now) be calculated.In one embodiment, the method comprises determining a load current change as a function of the transformer voltage change and the transformer impedance. The load current change, which can also be referred to as the dominant load current change, results in particular from the quotient of the transformer voltage change and the transformer impedance. In one embodiment, the method comprises determining a load share as a function of the natural coupling point current change and the load current change. In order to advantageously obtain the load share at the coupling point from the load current change, the natural coupling point current change can be divided by the load current change. In one embodiment, the method comprises determining a load allocation as a function of the load share, the loop impedance and the segment impedance.The load allocation can be determined by the quotient resulting from multiplying the loop impedance by the load allocation and the segment impedance. The load allocation preferably specifies a value range between zero and one, analogous to the proportion factors, where the value corresponds to a location or area within the first segment. The value of zero usually corresponds to the location of the outgoing circuit of the first segment, and the value of one to the location at the connection of the mesh current controller to the first segment. For each load allocation, the value of the detected load can be entered in the previously explained (created) tables. For this purpose, the entered value of the local load current can be updated for the corresponding load allocation.As already mentioned, the method can detect load changes, so that the tables usually contain the value zero in the local load current column when initially run. By updating the tables, a change in the load in the sub-areas can advantageously always be tracked. In one embodiment, the method comprises determining an outgoing current as a function of the load allocation and the load current change. The coupling point current can be recalculated from the determined loads. The coupling point current is usually the sum of all entries in the tables for the local load current. A load correction can then be calculated from the calculated value for the coupling point current using the natural coupling point current.The load allocation can be calculated from the quotient of the coupling point current and the natural coupling point current. The calculated load correction can then be offset against each value of the local load current for updating, in particular by multiplying each value in the table by the load correction. From the updated values ​​in the table, a first outgoing current and a second outgoing current can be calculated from the sum of the values ​​of the local load current multiplied by the respective route factor. In one embodiment, the method comprises determining a coupling point current setpoint as a function of the natural coupling point current and the outgoing current. The load-balancing coupling point current setpoint to be set by the mesh current controller can then be determined from the unaffected natural coupling point current and half the difference between the two outgoing currents.For this purpose, the natural coupling point current can be added to half the difference between the two outgoing currents. According to a second aspect of the invention, the stated object is achieved by a mesh flow controller with the features of patent claim 15. The mesh flow controller serves to regulate a voltage in a mesh, wherein the mesh flow controller has a controllable current or voltage source and is set up to independently carry out a method described here. Furthermore, the mesh flow controller can, for example, have one or more (or even all) of the following elements: connections for connecting the 14 2022P00039 WO Maschinenfabrik Reinhausen GmbH mesh flow controller to or in a mesh, inputs and outputs for connecting external sensors or signal sources in order to obtain information about the operating state of the system or other relevant parameters, a power supply unit for supplying power to the mesh flow controller orfor its electronics, signal processing components for processing and / or filtering the recorded signals, protective components or protective mechanisms for protection against overload, overvoltage or other malfunctions, measuring units for recording measured variables in the mesh, controllers for regulating the output of the mesh current controller, actuators for influencing the current flow in the mesh, such as power transistors or power switches, interfaces for communication between the mesh current controller and other systems or control components, feedback loops for feedback and adjustment of regulated values ​​of the current in the mesh. The details, features and advantageous embodiments discussed in connection with the method can also occur accordingly in the mesh current controller presented here and vice versa. In this respect, reference is made in full to the explanations there for a more detailed characterization of the features.According to a third aspect of the invention, the stated object is achieved by a system having the features of patent claim 16. The system serves to determine measured variables in a mesh of a low-voltage network and to regulate a voltage or a current in the mesh, wherein the system has a mesh current controller. In addition, the system has a determination unit for determining measured variables in the mesh on the mesh current controller. The details, features, and advantageous embodiments discussed in connection with the method can also occur accordingly in the system presented here, and vice versa. In this respect, reference is made in full to the statements therein for a more detailed characterization of the features. According to a fourth aspect of the invention, the stated object is achieved by use with the features of patent claim 17.The use comprises the use of a mesh current controller in a mesh of a low-voltage network, wherein no measuring points are used in the mesh outside the mesh current controller to determine measured variables for the mesh current controller 15 2022P00039 WO Maschinenfabrik Reinhausen GmbH. The details, features, and advantageous embodiments discussed in connection with the method can also occur in the use presented here, and vice versa. In this respect, reference is made in full to the statements therein for a more detailed characterization of the features. Further features, advantages, and possible applications of the present invention emerge from the following description of the exemplary embodiments and the figures.All of the features described and / or illustrated individually and in any combination form the subject matter of the invention, regardless of their composition in the individual claims or their references. In the figures, the same reference numerals continue to represent the same or similar objects. Figure 1 shows a schematic representation of an embodiment of a method described here for determining measured variables in a mesh of a low-voltage network, Figure 2 shows a schematic representation of a meshed low-voltage network, Figure 3 shows a schematic representation of an embodiment of a mesh current controller described here. Figure 1 shows a schematic representation of an embodiment of a method 100 described here for determining measured variables in a mesh of a low-voltage network.The sequence of the process steps represented by blocks 101 and 102 is essentially exemplary and can thus occur, for example, during regular operation of the process. Furthermore, it is conceivable that the process steps can be carried out at least partially in parallel or simultaneously. It is also conceivable that the process steps are carried out directly one after the other or at a time interval. The process step according to block 101 can be carried out, for example, during installation or commissioning of the mesh flow controller. The process step according to block 102 can be repeated several times during operation of the mesh flow controller. In particular, the process step according to block 102 can be carried out much more frequently than the process step according to block 101.In a first step 101, the method 100 comprises providing a mesh current controller in the mesh of the low-voltage network, wherein the mesh current controller has a controllable current or voltage source. In a second step 102, the method 100 comprises determining at least one measured variable of the mesh with the mesh current controller using the current or voltage source. As already mentioned, the method 100 described here is used in a mesh of a low-voltage network. An exemplary mesh in which the method can be used is shown in Figure 2; therefore, the method 100 is described in further detail below with reference to Figure 2. Figure 2 shows a schematic representation of an exemplary meshed low-voltage network 1 that is connected to a medium-voltage line 3.A transformer 5 for voltage transformation is provided between the low-voltage grid 1 and the medium-voltage line 3. A low-voltage grid 1 is a power grid that operates with low voltage, usually less than 1 kV, and is mostly used in distribution networks. To distribute the voltage, it is usually first distributed over long distances in a medium-voltage grid before the voltage is fed from the medium-voltage line 3 into the low-voltage grid 1 via the transformer 5. The low-voltage grid 1 can be designed as a three-phase alternating current network. In low-voltage grids, it is usually technically possible to form a mesh 7. The mesh 7 serves to ensure a high level of supply security, as any consumers can thus be supplied via an alternative line. A mesh current regulator 9 can be installed to regulate the current in the mesh 7.The mesh current regulator 9 is used to change the voltage level of the low-voltage network 1. By changing the voltage level, the current in the mesh 7 can be controlled, since coupling in a voltage changes the current distribution in the mesh 7. The mesh 7 can have a plurality of load connections 11, to which a plurality of consumers 13 and / or power sources 15, for example in the form of photovoltaic systems or small wind turbines, can be connected. Consumers 13 in a load connection 11 can be, for example, single-family or multi-family homes or commercial establishments, wherein the consumers 13 can each have one or more power sources 15. As a rule, a plurality of consumers 13 and / or power sources 15 are connected to a load connection 11.Due to the large number of consumers 13 and / or power sources 15, significant load changes can occur within the low-voltage network 1, which in extreme cases can lead to overloading of the load outgoing device 11 or the entire mesh 7. To prevent this, the mesh current controller 9 can regulate the current flow within the mesh 7. As already mentioned, the mesh current controller 9 can serve to ensure an even distribution of the current in the mesh 7. For this purpose, it is necessary for the mesh current controller 9 to know or be able to determine various currents, for example the outgoing currents at the coupling points on the transformer 5 or at various locations within the mesh 7. For this purpose, the mesh current controller 9 can have means for current and voltage measurement, preferably for each phase of the mesh 7.In order to be able to determine the current to be coupled in, various measured variables of the mesh 7 are used as an example with the method 100 using the current or voltage source. The various measured variables are explained below. The method 100 is described below using the mesh current controller 9 with a controllable voltage source, but the method 100 can also be carried out analogously with a mesh current controller 9 with a controllable current source. Figure 2 shows a loop 17 which indicates a current flow direction assumed for the method 100. First, a loop impedance Z17 of the loop 17 can be determined using the method 100. To determine the loop impedance Z17, the voltage source can be operated as an AC voltage source in phase with the mains voltage of the mesh 7 and adjusted so that a current of zero results at the coupling point of the mesh current controller 9.18 2022P00039 WO Maschinenfabrik Reinhausen GmbH In addition to the injected voltage, which was set to result in a zero current, a first differential voltage Ud9 can be applied by the voltage source. First, the first differential voltage Ud9 is applied as a positive voltage so that a first current value I17 set on the mesh current controller 9 can be measured. Subsequently, the first differential voltage Ud9 is applied as a negative voltage and finally the first current value I17 set on the mesh current controller 9 is measured again. This process can be repeated several times to result in several first current values ​​I17. A first average current value Ī17 can be calculated from the resulting several first current values ​​I17. The loop impedance Z17 is calculated using the following formula from the quotient of the voltage Ud9 and the average current value Ī17. ^^ ^^ = Ī ^^This determination can be carried out on all three phases simultaneously or on individual phases sequentially. The method 100, or the determination of the measured variables, is preferably carried out separately for each phase and is thus suitable for single-phase and multi-phase meshes 7. For simplicity, the following examples are explained using only one phase; however, they apply analogously to the remaining phases. The mesh 7 can be divided into a first segment 19 and a second segment 21, wherein, for example, the first segment 19 forms the path between the transformer 5 and an input side of the mesh current controller 9, and the second segment 21 forms the path between the transformer 5 and an output side of the mesh current controller 9.The loop impedance Z17 represents the sum of an impedance of the first segment 19, which can be referred to as the first segment impedance Z19, and an impedance of the second segment 21, which can be referred to as the second segment impedance Z21. To determine the first and second segment impedances Z19, Z21, the voltage source can be regulated to zero volts. A mains voltage U1 and a mains current I1 of the low-voltage network 1 can now be determined. A value for a target reactive current Iqs can then be specified for the loop current controller 9. As soon as the mesh current controller 9 has been adjusted so that the target reactive current Iqs has been set, the grid voltage U1 and the grid current I1 of the low-voltage grid 1 can be determined again and a second differential grid voltage U1d and a second differential grid current I1d can be calculated from the determined values.Once the differential grid voltage U1d and the differential grid current I1d have been calculated, the target reactive current Iqs can be reset to zero. This process can be repeated several times, and an average value for the differential grid voltage Ū1d and the differential grid current Ī1d can be calculated from the resulting multiple differential grid voltages U1d and differential grid currents I1d. Using the following formula, the first segment impedance Z19 can now be determined using the measured values. The second segment impedance Z21 is calculated using the following formula from the difference between the loop impedance Z17 and the first segment impedance Z19. ^ ^^ = ^ ^^ − ^ ^^ From the determined mean values ​​of the differential network voltage Ū1d and the differential network current Ī1d, a total network impedance Z1 can be determined using the following formula. The total network impedance Z1 can now be used to determine a transformer impedance Z5. To do this, a local segment parallel impedance Zsp is first determined from the parallel impedances of the first and second segment impedances Z19, Z21 using the following formula. 20 2022P00039 WO Maschinenfabrik Reinhausen GmbH The transformer impedance Z5 can now be determined as follows from the quotient of the total network impedance Z1 and the determined segment parallel impedance Zsp. From the previously determined measured variables, further characteristic values ​​can be determined, which are used for the real-time calculation of the load situation in mesh 7. For the subsequent calculations, the segments 19, 21 are virtually divided into sub-segments 23, 23', 25, 25'. In the present exemplary embodiment, the first segment 19 is divided into first sub-segments 23, 23', and the second segment 21 is divided into second sub-segments 25, 25'. The sub-segments 23, 23', 25, 25' can be of equal length or can be determined such that they have varying lengths. For example, it can be provided that the sub-segments 23, 23', 25, 25' have different lengths.On the one hand, the first sub-segments 23, 23' can differ in their length from the second sub-segments 25, 25' and, on the other hand, the first sub-segments 23, 23' or the second sub-segments 25, 25' can have different lengths from one another, whereby the sum of the first sub-segments 23, 23' always results in the length of the first segment 19 and the sum of the second sub-segments 25, 25' always results in the length of the second segment 21. Likewise, the sub-segments 23, 23', 25, 25' can be selected variably, for example in particular independently of the location of a load connection 11. Preferably, the sub-segments 23, 23', 25, 25' are selected such that at least one load connection 11 is located in one of the sub-segments 23, 23', 25, 25'. Particularly preferably, the sub-segments 23, 23', 25, 25' are selected such that there is a maximum of one load connection 11 in each of the sub-segments 23, 23', 25, 25'.This has the advantage that the measured variables determined for the respective sub-segments 23, 23', 25, 25' can always be assigned to a maximum of one load connection 11 that lies in the respective sub-segment 23, 23', 25, 25'. 21 2022P00039 WO Maschinenfabrik Reinhausen GmbH In Figure 2, the first segment 19 is divided, for example, into the two sub-segments 23, 23' and the second segment 21 is divided, for example, into the two sub-segments 25, 25'. Preferably, the segments 19, 21 are divided into more than two sub-segments, although in practice a division into 5 to 30 sub-segments each has proven advantageous. This has the advantage that a load can be allocated more precisely within one of the segments 19, 21. In general, the more subsegments a segment has, the more accurately a load can be allocated within that segment. As the number of subsegments increases, so does the computational requirements for determining the measured values ​​within mesh 7 and 8.of the sub-segments 23, 23', 25, 25', which is why dividing a segment into ten sub-segments has proven particularly advantageous. As already mentioned, each of the segments 19, 21 is divided into sub-segments 23, 23', 25, 25', whereby the sum of the sub-segments 23, 23', 25, 25' of the respective segment 19, 21 again results in the length of the respective segment 19, 21. This means that for each sub-segment 23, 23', 25, 25', a relative proportion factor A23, A25, A23', A25' between zero and one can be specified, which corresponds to the proportional, relative length of the segment 19, 21. For example, a sub-segment with the proportion factor 0.5 corresponds to half the length of the corresponding segment 19, 21. The division of the segments 19, 21 into sub-segments 23, 23', 25, 25' can preferably depend on the actual length of the segment 19, 21, whereby the number of sub-segments can increase with increasing length of the segment.If a segment is one kilometer long, for example, it can be divided into ten sub-segments, each 100 meters long. For correspondingly shorter segments, it is sufficient to divide the segment into fewer sub-areas, with each sub-segment preferably having a length of at least 50 meters. This has the advantage that each sub-segment only contains one consumer with a particularly high power requirement. Several single-family or multi-family homes, each with several households, can be considered a consumer with a particularly high power requirement. A consumer with a particularly high power requirement can also be a commercial enterprise, for example. A commercial enterprise generally has a higher power requirement than, for example, a single-family or multi-family home.22 2022P00039 WO Maschinenfabrik Reinhausen GmbH Using the component factors A23, A23', A25, A25', a partial segment impedance Z23, Z23', Z25, Z25' can now be determined. To do this, the respective component factor A23, A23', A25, A25' is multiplied by the respective segment impedance Z19, Z21 of the respective segment 19, 21 as follows. ^. ^^^ = ^ ^^ ∗ ^ ^^ The calculation of the subsegment impedances Z23', Z25, Z25' of the remaining subsegments 23', 25, 25' can be done analogously. Alternatively, the subsegment impedance Z23 can be calculated, for example, as follows. ^ ^^ = ^1 − ^ ^^^ ^ ∗ ^ ^^From the calculated sub-segment impedances Z23, Z23', Z25, Z25', the section factors SF(A23), SF(A23'), SF(A25), SF(A25') can now be calculated for each sub-segment. For example, for the section factor SF(A23) of sub-segment 23, a sub-segment parallel impedance Z23p is divided by the sub-segment impedance Z23' of sub-segment 23'. The following formula is used to calculate the section factor SF(A23) of sub-segment 23 as an example. The section factor SF(Ax) serves as a dimensionless parameter to determine which portion of a load current of a load connected in a sub-segment 23, 23', 25, 25' or at the respective virtual location, which can be defined by the component factors A23, A23', A25, A25', would flow naturally at the installation location of the mesh current controller 9, i.e., without influence from the mesh current controller itself. The section factors SF(Ax) preferably remain the same with unchanged impedances. 23 2022P00039 WO Maschinenfabrik Reinhausen GmbH To save the calculated values, these can be stored in a table Tx, whereby a separate table T19, T21 can be stored for each segment 19, 21, so that a first table T19 is created for entering values ​​of the first segment 19 and a second table T21 is created for entering values ​​of the second segment 21.Tables T19 and T21 can each contain three columns, with a local load current IAx, the component factor Ax, and the section factor SF(Ax) being stored in these three columns. When creating the table, the value zero can initially be saved for the local load current IAx. This is because method 100 can identify and calculate load changes within mesh 7 without the actual load having to be known. This has the advantage that method 100 can be executed without the need for initial parameterization. As already mentioned, significant load changes or current coupling at load connections 11 can lead to a load increase or load decrease in segments 19 and 21. In order to compensate for any load increases or load decreases, method 100 can now be used to determine a load-balancing coupling point current setpoint I9s.The coupling point current setpoint I9s specifies a setpoint for a coupling point current I9. To do this, a change in a natural coupling point current I9n can first be determined. The natural coupling point current I9n represents a current change that would occur at the coupling point of the mesh current controller 9 with direct coupling without the influence of the mesh current controller 9 due to a load change. The natural coupling point current I9n is calculated as follows from the regulated coupling point current I9 of the mesh current controller 9, the voltage value Uq of the voltage source, and the loop impedance Z17. To determine the change in the natural coupling point current I9n, which can also be referred to as the natural coupling point current change Id9n, the natural coupling point current I9n can be determined at a first time T1 and a second time T2. The subsequent calculation of the difference between the two values ​​yields the natural coupling point current change Id9n. ^ ^^^ = ^ ^^ ^^ ^ ^ − ^ ^^ ^^ ^ ^; In addition to determining the natural coupling point current change Id9n, a first connection voltage change U19d, U21d at the two connection points of segments 19, 21 can be determined by determining the voltage at the connection point of the first segment 19 at time T1 and the voltage at the connection point of the first segment 19 at time T2. Analogously, a second connection voltage change U21d at the connection point of the second segment 21 can also be determined. Based on the two connection voltage changes U19d, U21d, a dominant load change can be determined. To do this, it is first determined in which segment the load change occurred. This is done, for example, using the following case distinction. If the consumption current via the coupling point from the first segment 19 to the second segment 21 becomes more positive, a load drop in the second segment 21 is assumed when the first connection voltage change U19d increases.If the first connection voltage change U19d decreases, a load increase in the first segment 19 is assumed. If the consumption current across the coupling point from the first segment 19 to the second segment 21 becomes negative, a load drop in the first segment 19 is assumed when the second connection voltage change U21d increases. If the second connection voltage change U21d decreases, a load increase in the second segment 21 is assumed. Based on this determination, a compensating current I9d can now be calculated. The compensating current I9d can then be calculated using the measured values ​​of the first segment 19; however, the following steps apply analogously to the second segment. 25 2022P00039 WO Maschinenfabrik Reinhausen GmbH First, a line voltage change Udl is calculated from the product of the natural coupling point current change Id9n and the segment impedance Z19. ^. ^^ = ^ ^^^ − ^ ^^The line voltage change Udl and the first connection voltage change U19d result in a transformer voltage change U5d. ^ ^^ = ^ ^^^ − ^ ^^ The dominant load current change I7d is now the result of the transformer voltage change U5d and the transformer impedance Z5. ^ ^ = ^^ ^^ ^^ In order to obtain the load component Rx at the coupling point from the load current change I7d, the natural coupling point current change Id9n is divided by the load current change I7d. The following formula can be used to determine a load allocation ARx based on the load component Rx, the loop impedance Z17 and the segment impedance Z19. Analogous to the proportion factors A23, A23', A25, A25', the load allocation ARx specifies a value range between zero and one, where the value corresponds to a location within the first segment 19. The value of zero corresponds to the location of the outgoing feeder of the first segment 19, and the value one to the location at the connection of the mesh current controller 9 on the first segment 19. The load allocation ARx can now be entered into the previously described table T19, T21. For this purpose, the entered value 26 2022P00039 WO Maschinenfabrik Reinhausen GmbH of the local load current IAx is updated for the corresponding load allocation ARx. As already mentioned, the method detects 100 load changes, so that the tables T19, T21 contain the value zero in the column for the local load current IAx when run for the first time. The update of the local load current IAx is calculated as follows. By updating tables T19 and T21, a change in the load in sub-areas 23, 23', 25, and 25' can be continuously tracked. The coupling point current I9 can be recalculated from the determined loads. The coupling point current I9 results from the sum of all entries in tables T19 and T21 for the local load current IAx and can be calculated as follows. Where n represents all entries in the first table T19 and m represents all entries in the second table T21. From the calculated value for the coupling point current I9, a load correction DI can now be calculated using the natural coupling point current I9n as follows. ^ * = ^ + ^^^^^^ The calculated load correction DI is now calculated with each value of the local load current IAx for updating by multiplying each value in tables T19, T21 by the load correction. ^ #" $^ !" % ← ^ #" $^ !" % ∗ * +From the updated values, a first outgoing current I19 and a second outgoing current I21 can be calculated from the sum of the local load current values ​​in Tables T19 and T21 as follows: 27 2022P00039 WO Maschinenfabrik Reinhausen GmbH The load-balancing coupling point current setpoint I9s to be set by the mesh current controller 9 can now be determined as follows from the unaffected natural coupling point current I9n and half the difference between the two outgoing currents I19, I21. ^ ^ ^^ − ^ ^^ ^^ = ^ ^^+ 2 As already mentioned, method 100 can also determine the measured values ​​with separate determination of the real and imaginary parts. In this case, the previously mentioned method steps of method 100 could determine active power and reactive power separately. This would have the advantage of enabling a more precise determination of the measured variables. The previously described method 100 for determining measured variables in mesh 7 works iteratively, preferably purely iteratively. This means that method 100 maintains a load state of mesh 7 without requiring the exact load state of mesh 7. This has the advantage that method 100 does not require initialization and does not require the input of any measured values ​​in mesh 7. Therefore, no external measured values ​​or measuring points in mesh 7 are required to implement method 100. As already described, method 100 is implemented by mesh current controller 9. Typically,a mesh 7 or the lines of mesh 7 where the mesh current controller 9 is installed are switched black so that no current flows. When the mesh current controller 9 is then put into operation, method 100 can be executed. Since there is generally no overload situation in mesh 7 when the mesh current controller 9 is put into operation, method 100 is able to maintain the load state so that no overload situation can occur. Method 100 therefore reacts to changes within mesh 7. The changes are determined, as previously described, by determining the various measured variables. Method 100 reacts to any changes with a compensating coupling point current I9. In a preferred embodiment of the method 100, the load-balancing coupling point current I9 is ​​only changed if the method 100 detects a change in the measured variables in the mesh7 is detected. As already mentioned, the method 100 is carried out by the mesh current controller 9. An exemplary mesh current controller 9 that is suitable for carrying out the method 100 is shown in Figure 3. Figure 3 shows a schematic representation of an embodiment of a system 27 with a mesh current controller 9 described here. The mesh current controller 9 has a coupled voltage source 29 that can be controlled via a determination unit 31. Instead of the voltage source 29, a current source can also be provided. For this purpose, the voltage source 29 has a bidirectional power supply unit 33. The mesh current controller 9 is connected in series with the three phases of the mesh 7. The determination unit 31 is also connected to the three phases of the mesh 7 and for this purpose has a current and voltage measuring device 35 for each phase. In addition, the determination unit 31 is connected to the voltage source 29 via a first connecting line 37.Via the first connecting line 37, the determination unit 31 supplies the voltage source 29 with a setpoint voltage that is to be coupled in order to achieve the setpoint for the load-balancing coupling point current I9s. In the event that a current source is provided instead of the voltage source 29, the determination unit 31 supplies the load-balancing coupling point current I9s that is to be coupled in via the first connecting line 37. The determination unit 31 is connected to the power supply unit 33 via a second connecting line 39, via which the determination unit 31 supplies the setpoint reactive current Iqs to the power supply unit 33. The mesh current controller 9 has an internal control loop that supplies the voltage setpoint to the voltage source 29. The 29 2022P00039 WO Maschinenfabrik Reinhausen GmbH setpoint for the load-balancing coupling point current I9s is achieved with the voltage setpoint. The current and voltage measuring device 35 providesThe determination unit 31 regularly measures the coupled measured variables so that it can always be determined whether the setpoint for the load-balancing coupling point current I9s has been reached. In a preferred embodiment, the inner control loop has an update rate of 100 µs. To determine the load-balancing coupling point current I9s, the mesh current controller 9 has an outer control loop. The outer control loop is preferably an open control loop. The outer control loop provides a value for the load-balancing coupling point current I9s, which is used as an input variable by the inner control loop. The inner control loop can preferably be designed as a current controller. The current controller operates the voltage source (actuator, voltage source converter) with its control value and regulates to the load-balancing coupling point current I9s, which it receives from the outer control loop. This current controller has a high update rate andThis maintains the current of the mesh current controller representing the grid coupling at the specified value, even during load changes in the grid. This is a significant advantage, as it actively prevents overloading of the coupling point. The current is controlled using two voltage vectors. One of the vectors is in phase or in the same direction as the grid voltage, with the output of an integrator or an integrator and proportional element determining the amplitude of this component based on the setpoint difference of the active current component of the setpoint (I or PI controller). The second vector is orthogonal to the first and thus also to the grid voltage, with the output of an integrator or an integrator and proportional element adjusting the amplitude of this component based on the setpoint difference of the reactive current component of the setpoint (I or PI controller). The resulting manipulated variable is a voltage that is supplied from the voltage source converter.is passed on. This results from the vectorial addition of the two components. In a preferred embodiment, the outer control loop has an update rate of 100 ms. In a further preferred embodiment, the outer control loop has an observation or estimation element that provides an estimate for the load-balancing coupling point current I9s. 30 2022P00039 WO Maschinenfabrik Reinhausen GmbH In Figure 2, the mesh flow controller 9 is shown only schematically as being in the middle of the mesh 7, so that the two segments 19, 21 are of equal length. However, the method 100 allows the mesh flow controller 9 to be installed at any location in the mesh 7. Because the mesh flow controller 9 neither needs to be initialized nor requires external measuring points within the mesh 7, it can be installed and put into operation at any location. As already mentioned, the mesh flow controller 9 reacts toChanges within the mesh 7, which can be determined with the method 100 described here at any point in the mesh 7, regardless of the installation location of the mesh current controller 9 described here. In summary, it can be said that with the method 100 described here, measured variables in the mesh 7 can be determined in a particularly simple manner, in particular without the need for decentralized or distributed (additional) measuring units within the mesh 7, so that in particular no extensive reconstruction measures within the mesh 7 are necessary. Furthermore, it is particularly possible to achieve the highest possible supply security of a low-voltage network 1 by controlling the current flows in the mesh 7 in an advantageously simple manner, preferably without the need for extensive reconstruction measures within the mesh 7. In addition, it should be noted that "having" does not include any otherexcludes elements or steps, and "one" or "an" does not exclude a plurality. Furthermore, it should be noted that features described with reference to one of the above embodiments can also be used in combination with other features of other embodiments described above. Reference symbols in the claims are not to be considered as limitations. 31 2022P00039 WO Maschinenfabrik Reinhausen GmbH List of reference symbols 1 Low-voltage network 3 Medium-voltage line 5 Transformer 7 Mesh 9 Mesh current controller 11 Load connection 13 Consumer 15 Current source 17 Loop 19 First segment 21 Second segment 23 First sub-segments 25 Second sub-segments 27 System 29 Voltage source 31 Determination unit 33 Power supply unit 35 Current and voltage measuring device 37 First connecting line 39 Second connecting line 100 Method 101 First method step 102 Second method step Z17 Loop impedance Ud1 First differential voltage I17First current value I17' First mean current value R17 Real part loop impedance 32 2022P00039 WO Maschinenfabrik Reinhausen GmbH X17 Imaginary part loop impedance Z19 First segment impedance Z21 Second segment impedance U1 Mains voltage I1 Mains current Iqs Target reactive current U1d Differential mains voltage I1d Differential mains current Ū1d Mean value of the differential mains voltage Ī1d Mean value of the differential mains current Z1 Total mains impedance Zsp Segment parallel impedance Z5 Transformer impedance A23 Proportion factor of the sub-segments (Lok_rel) Z23 Sub-segment impedance SF(Ax) Section factor I9 Coupling point current I9n Natural coupling point current Id9n Natural coupling point current change U19d First connection voltage change U21d Second connection voltage change Udl Line voltage change U5d Transformer voltage change I7d Load current change Rx Load share Ax Load allocation IAx Load current T19 first table T21 second table DI Load correction I19 first outgoing current I21 second outgoing current 33 2022P00039 WO

Claims

Maschinenfabrik Reinhausen GmbH Patent Claims 1. Method (100) for determining measured variables in a mesh (7) of a low-voltage network (1), wherein the method (100) comprises the following steps: providing a mesh current controller (9) in a mesh (7) of a low-voltage network (1), wherein the mesh current controller (9) has a controllable current / or voltage source (29); and determining at least one measured variable of the mesh (7) with the mesh current controller (9) using the current / or voltage source (27).

2. Method (100) according to the preceding claim, wherein the method (100) comprises the following step: determining a loop impedance.

3. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining at least one segment impedance as a function of the loop impedance. 4.Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a transformer impedance.

5. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following steps: determining a virtual location factor of a load connection (11) connected in the mesh (7); and determining at least one section factor as a function of the location factor and the segment impedance.

6. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: 34 2022P00039 WO. Maschinenfabrik Reinhausen GmbH Controlling a current setpoint of the controllable voltage source via two voltage vectors, wherein one of the voltage vectors is in phase with the mains voltage in the same direction and the other of the two voltage vectors is orthogonal to the first voltage vector.

7. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a natural coupling point current.

8. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a line voltage difference as a function of the segment impedance and a natural coupling point current change.

9. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a transformer voltage change as a function of a terminal voltage change and the line voltage difference.Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a load current change as a function of the transformer voltage change and the transformer impedance.

11. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a load proportion as a function of the natural coupling point current change and the load current change.

12. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a load allocation as a function of the load proportion, the loop impedance and the segment impedance.

13. Method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: 35 2022P00039 WO. Maschinenfabrik Reinhausen GmbH Determining an outgoing current as a function of the load allocation and the load current change.

14. The method (100) according to one of the preceding claims, wherein the method (100) comprises the following step: determining a coupling point current setpoint as a function of the natural coupling point current and the outgoing current.

15. A mesh current controller (9) for controlling a voltage in a mesh (7), wherein the mesh current controller (9) has a controllable current / or voltage source (29) and is configured to independently execute a method (100) according to claims 1 to 14.

16. A system (27) for determining measured variables in a mesh (7) of a low-voltage network (1) and for regulating a voltage in the mesh (7), the system (27) comprising: a mesh current controller (9) with a determination unit (29) for determining measured variables in the mesh (7) on the mesh current controller (9). 17.Use of a mesh current controller (9) in a mesh (7) of a low-voltage network (1), wherein no measuring points in the mesh (7) outside the mesh current controller (9) are used to determine measured variables for the mesh current controller (9). 36 2022P00039 WO.

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