DE102013008812A1 - System and method for determining electrical characteristics - Google Patents

Abstract

The invention relates to a system for determining electrical parameters of consumers (1) in a branched power network (2), comprising a central control and evaluation unit (3), a central voltage measuring unit (4) and a plurality of decentralized units (5), each comprising a decentralized current measuring unit (6) with at least one current sensor (7), a decentralized voltage detection means (8) and a decentralized evaluation unit (9), the decentralized units (5) being assigned to the consumers (1), the central control unit and evaluation unit (3) is connected via connections (10) to the central voltage measuring unit (4) and to the decentralized units (5), whereby a voltage value can be measured and made available by the central voltage measuring unit (4), and wherein the decentralized evaluation unit (9) via connections (11) with the decentralized current measuring unit (6) and the decentralized voltage detection means (8) is connected, instantaneous values of a current being measurable and made available for transmission by the decentralized current measuring unit (6) and wherein a voltage profile can be detected and made available for transmission by the decentralized voltage detection means (8), and wherein the transmission the instantaneous values of the current and the detected voltage curve are carried out by the connections (11) from the decentralized current measuring unit (6) and the decentralized voltage detection means (8) to the decentralized evaluation unit (9), and the decentralized evaluation unit (9) determines the zero crossing from the voltage curve of the voltage, a calculated sine curve of the voltage being provided on the basis of the determined zero crossings, and the decentralized evaluation unit (9) assigning the instantaneous values of the current to the values of the calculated sine curve of the voltage, the instantaneous values being used n of the current and the respectively assigned values of the calculated sine curve of the voltage, normative instantaneous values of the power are formed and a normative intermediate power value is formed from the normative instantaneous values of the power and is made available as an intermediate power value, and wherein the intermediate power value is provided via the connection (10) is transmitted from the decentralized evaluation unit (9) to the central control and evaluation unit (3), and wherein the central control and evaluation unit (3) interrogates the voltage value and the intermediate power value, and wherein the central control and evaluation unit (3 ) the active electrical power of the respective consumer (1) is calculated from the voltage value and the intermediate power value. The invention further relates to a method for determining electrical parameters of consumers in a branched power network.

Description

The invention relates to a system and the associated method for determining electrical parameters, in particular the active power, decentralized consumers at arbitrary positions within a power grid.

Systems, devices and methods for determining active power are generally known in the art.

As a rule, so-called electricity or energy meters are used, which, primarily via electronic means via sensors and circuits, the current and the voltage, as well as the occurring between these phase shift, determine in the respective power grid.

From the determined data for current, voltage and phase shift, it is then possible to determine the active power applied in the respective power network.

In times of rising energy costs, it is becoming increasingly important, especially for manufacturing companies, to determine the effective power of individual consumers within a power grid in order to be able to target them and improve their effectiveness.

If one wanted to implement such a project with the energy meters known from the prior art, it would become necessary to provide such an energy meter separately for each individual consumer and to process the metrological signals or values in a complex manner.

This would be associated with an immense installation and measuring effort and thus uneconomical and expensive for power grids with many consumers. In addition, the known energy meters require a correspondingly large space and thus a subsequent installation of these in existing power grids is often not feasible.

In order to eliminate these disadvantages, devices and methods are also known from the state of the art, which only determine the respective current value of each consumer, then calculate it with a stored voltage value and taking into account a previously determined effective factor stored for the respective consumer that determines active power.

Such a device is for example in publication DE 198 27 345 B4 discloses and has a plurality of measuring points, and a central processing unit.

The measuring points are each assigned to a consumer and detect the respective current values applied to the consumer.

Subsequently, the detected current values are transmitted to the arithmetic unit and combined there with a voltage signal.

The voltage signal is determined for this purpose at selected points of the power grid.

The disclosed invention disadvantageously provides that for the conditioning of the device and thus for the determination of the active power, valid characteristic values for the magnitude of the active power reference and of the power factor must be determined for each individual load for characteristic operating states. The determined characteristic values are then stored in a database for further use and, depending on the fluctuation of the mains voltage, used to calculate the active power of the individual consumers.

This preliminary determination of the characteristic characteristics of each consumer in different operating states leads to a large preparation effort and thus to high preparation and test costs.

Another technologically advanced solution for determining electrical characteristics is from publication DE 10 2011 107 932 B3 known.

In this case, the determination of the electrical characteristics, in particular the determination of the active energy of a consumer in a branched power grid by means of a central control and evaluation, a central voltage measuring unit and a plurality of decentralized current measuring units.

In consideration of the, usually occurring in inductive or capacitive loads, phase shift between current and voltage during the determination of the active power can be dispensed with in the solution listed that a time stamp is issued by the central control and evaluation and that by the voltage measuring unit and the current measuring units instantaneous values of the voltage or of the current are measured, to which the time stamp is assigned and which are assigned to one another on the basis of the time stamp in the central control and evaluation unit and from these subsequently the electrical parameters are determined.

Object of the present invention is to provide an alternative approach to provide a system and method for determining electrical characteristics, which the Disadvantages of the prior art avoids and by which a simple and cost-effective determination of the electrical parameters, in particular the active power and the active work of a large number of electrical loads within an alternating voltage network with a central feed point allows.

The object is achieved with respect to the system by the features listed in the claims 1 and 12. Preferred developments emerge from the respective subclaims.

With regard to the method, the object is achieved by the features listed in claim 13. Preferred developments of the method emerge from the claims 14 to 18.

An inventive system for determining electrical characteristics of consumers in a branched power network has a central control and evaluation unit, hereinafter also referred to as a controller, a central voltage measuring unit, and a plurality of decentralized units.

According to the invention, the decentralized units are assigned to the respective consumers.

On the other hand, the central control and evaluation unit is connected via connections both to the central voltage measuring unit and to the decentralized units.

According to the invention, the central voltage measuring unit is used to measure a voltage value of the voltage U present in the power grid at a central voltage measuring point within the power grid.

In contrast to conventional systems, in a system according to the invention only a single voltage measuring point within the power network is required, which on the one hand reduces the technical equipment and installation costs and on the other hand the necessary measurement effort.

A feed point near measurement of the voltage is also achieved as a particular advantage that the power loss components and distortions occurring in the power grid to the consumer, in particular by voltage drop under load, are included in the determination of the ultimately resulting active power and active work.

The measurement of the voltage value by the central voltage measuring unit takes place in a manner known per se either digitally or analogously.

Another advantage of the solution according to the invention is that only an effective value of the voltage has to be measured by the central voltage measuring unit and made available in a transferable manner. On a technically complex provision and transmission of relevant instantaneous values of the voltage can thus be advantageously dispensed with.

According to the invention, the decentralized units each have a decentralized current measuring unit, a decentralized voltage detection means and a decentralized evaluation unit, wherein the decentralized evaluation unit is connected via connections to the decentralized current measuring unit and the decentralized voltage detection means.

The decentralized current measuring unit according to the invention is capable of measuring the value of the current I flowing through the respective conductors for connection of the consumer.

According to the invention, a measurement of the instantaneous values of the current takes place here.

If it is a consumer of a multi-phase circuit, as is the case for example with a three-phase AC circuit, each conductor is assigned a separate decentralized current measuring unit. In such a case, the decentralized current measuring units are either individually connected to the decentralized evaluation unit, or summarized, for example via a serial BUS, so that a BUS line is looped through from decentralized current measuring unit to decentralized current measuring unit.

The measurement of the current I at the respective consumer by the decentralized current measuring unit is preferably carried out in a manner known per se using the Hall effect; In addition, however, any other suitable form of current measurement, for example inductive, can also be used according to the invention. It is expedient to carry out the current measurement without contact in order to ensure a galvanic separation of the power line and the current sensor.

The measured instantaneous values of the current are provided in a transferable manner according to the invention by the decentralized current measuring unit and transmitted to the decentralized evaluation unit via the respective connection.

Parallel to the measurement of the instantaneous values of the current, a detection takes place according to the invention by the decentralized voltage detection means of, at the respective conductor for connection of the consumer voltage applied.

The detected voltage profile is provided by the decentralized voltage detection means transferable and also transmitted via the respective connection to the decentralized evaluation unit.

According to the invention, the decentralized evaluation unit is able to carry out a zero-crossing determination of the voltage from the transmitted voltage curve and to provide a calculated sinusoid of the voltage on the basis of the zero crossings determined thereby.

The calculated sinusoid is an idealized voltage curve, for the calculation of which an arbitrary voltage value to be defined, for example 100 V, is assumed, whereby the voltage value to be defined represents only a calculation aid and can be selected independently of the actual voltage.

In addition, the decentralized evaluation unit is particularly advantageous in being able to make an assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage.

In this case, the assignment takes place, for example, in the form that the calculated sinusoidal curve is first provided and then the measurement of the instantaneous values of the current by the decentralized current measuring unit and its transmission to the decentralized evaluation unit are started at a defined time, for example at an applied zero crossing of the voltage , The instantaneous values of the current are then measured for the duration of a fixed time interval, which can preferably be determined by the calculated sinusoid, and transmitted to the decentralized evaluation unit so that it can assign an instantaneous value of the current to each value of the calculated sinusoid.

Furthermore, according to the invention, the decentralized evaluation unit uses the instantaneous values of the current and the assigned values of the calculated sine curve to form normative instantaneous values of a power of the respectively applied consumer.

The term normative here means that the power values formed at this point have only a normative character and no concluding exactness due to the values of the sinusoid of the voltage which are calculated on the basis of a defined voltage in an idealized manner.

In addition, according to the invention, the decentralized evaluation unit is able to form a normative intermediate power value from the normative instantaneous values of the power and to make it available as an intermediate power value in a transferable manner.

The normative power intermediate value is formed by the integral of the normative instantaneous values of the power.

According to the invention, the intermediate power value formed is transmitted via the respective connection from the decentralized evaluation unit to the central control and evaluation unit, after it has performed a query of the intermediate power value and the voltage value.

Preferably, an identifier is associated with the intermediate power value, which allows identification of the respective consumer belonging to the intermediate power value.

The identifier is provided here by conventional means, for example a corresponding coding.

After transmission of the power intermediate value and the voltage value, the central control and evaluation unit according to the invention is able to calculate from these values the exact electrical active power of the respective load, wherein in the present case the power intermediate value is preferably multiplied by a corresponding correction value.

In this case, the correction value represents a value for the deviation of the voltage value, determined by the central voltage measuring unit, from a normative voltage value of the calculated sinusoid of the voltage.

The solution according to the invention offers the particular advantage that, for the determination of the active power of a load in a branched power network, the actual voltage values must be recorded only at a single central point and preferably near the point of supply, and thus not one power and one for each consumer Voltage measuring unit must be provided.

In addition, in the present case only a relatively small effort for the data collection and transmission is necessary because only in the course of the voltage value determination at the central voltage measuring unit only the rms value of the voltage and the decentralized voltage detection means only the zero crossings of the voltage must be determined and transmitted. A Measurement and transmission of a multiplicity of concrete instantaneous values is therefore not necessary according to the invention.

In the solution according to the invention, the data transmission effort can also be kept low in particular by virtue of the fact that the intermediate power unit already has the intermediate power value formed, and thus only this intermediate power value has to be transmitted via the corresponding connection to the central control and evaluation unit.

In addition, another technological advantage of the invention is that a determination of the phase angle φ (phi) of a consumer - either in advance or during the determination of the parameters - is not necessary, since the active power calculated from the calculated zero crossings of the voltage Sine wave in relation to the instantaneous values of the current results. From this, however, the phase angle φ (phi) can optionally also be determined as additional information.

In addition, it is possible according to the invention that the determined value of the active electrical power of the respective load can be output by the central control and evaluation unit.

The output of the active electrical power takes place, for example, visualized or archived. The output value of the active electrical power can also be used for control purposes, for example, to perform priority circuits to avoid the exceeding of load profile or for emergency shutdown in case of detected disturbances of a consumer.

An inventive system thus allows not only the determination of the active electrical power but also an assessment and evaluation of the consumers in a power grid in terms of their efficiency, efficiency and technical performance.

Although the invention primarily aims at the use of power grids with consumers such as electric motors or production machines; However, this can also be used in all other conceivable electrical consumers in a power grid.

Especially in power grids with a variety of electrical consumers, as is the case for example in production plants of companies, the system of the invention is an uncomplicated and above all cost solution for detecting the effective electrical power of a connected consumer and to assess its efficiency, or the correct energetic Evaluation of an overall system of several consumers provided in the respective power grid.

In addition, the technical solution outlined makes it possible for the companies to allocate the energy costs incurred in the manufacture of their products to the individual consumers and the process steps they carry out. As a result, the respective process steps can be optimized and thus the production costs for the product produced in each case can be reduced overall.

In a preferred embodiment of the invention, the central voltage measuring unit and / or the respective decentralized unit are assigned memory elements, by means of which measured voltage values or determined intermediate power values can be temporarily stored.

Such an intermediate storage of the measured values is particularly advantageous if the transmission of the values to the central control and evaluation unit should not be real-time but time-delayed to the actual measurement or determination process of the values.

In this case, the transfer of a voltage value, or an intermediate power value to the controller takes place only when it polls the respective value from the respective buffer.

The transfer of the voltage or power intermediate value to the central control and evaluation unit takes place in an advantageous embodiment of the invention by modulation of the respective values, as digitized values, on the power grid.

The method of modulating on the power grid is considered in this context as known from the prior art, which is why this will not be discussed here.

The modulating of the intermediate voltage and power values on the existing power network has the particular advantage that no additional connections between the controller and the central voltage measuring unit, or between the controller and the respective decentralized unit must be provided.

The necessary installation effort for a system according to the invention can thus be reduced efficiently.

In an equally preferred embodiment of the invention, the connection of the control and evaluation unit with the central voltage measuring unit and the respective decentralized unit is wirelessly formed.

In this case, the central voltage measuring unit and the respective decentralized unit each have separate transmitters for transmitting the measured values and the control and evaluation unit has a corresponding receiver for receiving the transmitted values. Such a wireless connection can be realized for example by radio or via W-LAN network. In addition, all other types of wireless connections are conceivable.

In any case, the use of a wireless connection particularly advantageously eliminates additional connecting lines between the control and evaluation unit and the voltage measuring unit, or the respective decentralized unit.

A further preferred variant of the system according to the invention provides that the central voltage measuring unit is integrated in the central control and evaluation unit.

As a result, on the one hand, the installation effort for a system according to the invention can be further advantageously reduced, and on the other hand, the integration of the central voltage measuring unit into the control and evaluation unit reduces the required installation space for installing the system.

This is particularly advantageous if a system according to the invention is to be subsequently installed in an existing power grid with few structural clearances.

When integrating the central voltage measuring unit into the control and evaluation unit, an equally advantageous further development of the invention provides that the connection between the control and evaluation unit and the central voltage measuring unit takes place via an internal processor bus within the controller. Since a processor bus is generally already present in the control and evaluation unit for data transmission and / or control purposes, in the embodiment described here, it is used particularly advantageously simultaneously for transmitting the data between the central voltage measurement unit and the controller. The need to transmit the voltage values externally, for example via the external BUS, is eliminated.

Furthermore, a decentralized unit is formed in a further advantageous variant of the invention as a decentralized master unit, which is connected to the central control and evaluation unit and at least one further decentralized unit via in each case a corresponding connection.

Subsequently, at least one further decentralized unit, which is not decentralized master unit, shortened referred to as a decentralized unit.

In the variant shown here, the connection of the decentralized unit to the central control and evaluation unit thus indirectly via the decentralized master unit, so that an intermediate power value of the decentralized unit to the decentralized master unit and are transmitted from this to the central control and evaluation unit.

According to the invention, the transmission of the intermediate power value from the decentralized master unit to the central control and evaluation unit can take place either directly following the transmission of the intermediate power value from the decentralized unit to the decentralized master unit or only after the intermediate power value has been buffered in the decentralized master unit.

The particular advantage of the variant shown here is in particular that a direct connection does not have to be provided between each decentralized unit and the central control and evaluation unit. In particular, with large spatial distances between the central control and evaluation unit and several decentralized units can be significantly reduced in this way the necessary installation costs.

In a further advantageous embodiment of the invention, the decentralized unit of the system is able, based on the assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage to determine a phase angle φ (phi) for the relevant consumer and transferable or optional to provide distributable.

In this case, an output of the phase angle preferably takes place directly at the decentralized unit, for example via a corresponding display. From the knowledge of the phase angle can be drawn conclusions about the operating behavior. As a particular advantage, no separate determination of the phase angle must be performed, but this is available as an added benefit of the system according to the invention and can also be evaluated and archived in a uniform data processing and management.

Furthermore, in a particularly advantageous development, the decentralized unit is based on a rated voltage value for the calculated sinusoid.

In this context, the nominal voltage value is preferably assumed to be a value which approximates with sufficient accuracy to the nominal voltage applied to the load and associated with the local power supply. For example, this is based on a nominal voltage value of 230 V.

The resulting advantage consists, in particular, in the fact that, as a result of the assumption of the approximately correct voltage value, an approximately correct value for the active power of the load can already be ascertained and transferred, or can be output, in the decentralized unit.

An output of the approximately correct value of the active power can be done in this case, for example, directly via a display of the decentralized unit.

In this case, a correction of the active power value determined on the basis of a nominal voltage value can be carried out in the central control and evaluation unit on the basis of the actual voltage value transmitted by the central voltage measuring unit.

A further advantageous variant of the invention provides that the decentralized voltage detection means is formed by the current sensor of the decentralized current measuring unit.

In this case, a voltage signal, capacitively coupled to the current sensor, can be evaluated by the decentralized evaluation unit for detecting the voltage profile as a particular advantage.

According to the invention, the variant listed here includes the fact that the capacitively coupled voltage signal is first phase-corrected due to its capacitive phase shift.

The particular advantage lies in this case is that such a voltage detection uses the already required technical resources for decentralized current measurement and thus can be realized particularly cost-effective.

In addition, in an advantageous development of the central voltage measuring unit, the voltage value additional information about a detection time window of the voltage value can be assigned.

The additional information can also be transmitted in a transferable manner together with the voltage value and is transmitted via the corresponding connection to the central control and evaluation unit.

In addition, the decentralized unit can be used to assign additional information about an acquisition time window of the underlying instantaneous values of the current to the intermediate power value.

This additional information can also be transmitted in a transferable manner together with the intermediate power value and according to the invention is transmitted to the central control and evaluation unit via the corresponding connection.

In the present development, the central control and evaluation unit is able to determine the exact effective electrical power from a voltage value and an intermediate power value, each with matching acquisition time windows.

The particular advantage of the development shown here is in particular that the respective voltage and power intermediate value is accompanied by time information about the time or period of the measurement, which of the central control and evaluation unit an exact temporal assignment of the values to each other and thus an exact time determination the electrical active power allows. This exact determination is particularly time-offset and real-time independent executable and allows accurate analysis of the performance.

Alternatively, a system for determining electrical characteristics of a consumer in a branched power network is formed by a decentralized unit which is assigned to the consumer.

According to the invention, the decentralized unit has a decentralized current measuring unit with at least one current sensor, a decentralized voltage detection means and a decentralized evaluation unit, wherein the decentralized evaluation unit is connected via connections to the decentralized current measuring unit and the decentralized voltage detection means, instantaneous values of a current being measurable by the decentralized current measuring unit, and be made available transferable and wherein by the decentralized voltage detection means, a voltage curve can be detected and provided transferable available.

According to the invention, the instantaneous values of the current and of the detected voltage profile are transmitted via the connections from the decentralized current measuring unit and the decentralized voltage detection means to the decentralized evaluation unit.

Moreover, the decentralized evaluation unit according to the invention is able to perform a zero-crossing determination of the voltage from the voltage curve, wherein a calculated sinusoid of the voltage is provided on the basis of the determined zero crossings.

Furthermore, according to the invention, the decentralized evaluation unit assigns the instantaneous values of the current to the values of the calculated sinusoid of the voltage, whereby normative instantaneous values of the power are formed from the instantaneous values of the current and the respectively assigned values of the calculated sinusoid of the voltage and from the normative instantaneous values the power is made a normative intermediate power value of the consumer and made available to be distributed.

The output of the intermediate power value takes place, for example, via a display which is assigned to the decentralized evaluation unit and which represents the intermediate power value as a number or, alternatively, within a diagram, for example.

Alternatively or cumulatively, the output can also take the form of a forwarding of the intermediate power value, for example to a corresponding data processing and output unit.

The solution shown here is used in particular when an approximately exact statement about the active power of the consumer based on the intermediate power value is sufficient.

An inventive method for determining electrical characteristics, in particular for determining the active power of consumers in a branched power network is performed by means of a central control and evaluation unit, by means of a central voltage measuring unit and by means of a plurality of decentralized units, wherein the central control and evaluation unit via connections is connected to the central voltage measuring unit and the decentralized units and wherein the decentralized units are associated with the consumers and each having a decentralized current measuring unit, a decentralized voltage detecting means and a decentralized evaluation unit, wherein the respective decentralized evaluation unit via connections to the respective decentralized current measuring unit and the respective decentralized Voltage detecting means is connected.

• a) Messen eines Spannungswertes durch die zentrale Spannungsmesseinheit,
• b) Messen von Augenblickswerten des Stroms durch die dezentrale Strommesseinheit,
• c) Erfassen eines Spannungsverlaufs durch das dezentrale Spannungserfassungsmittel,
• d) Übertragen der Augenblickswerte des Stroms und des erfassten Spannungsverlaufs über die Verbindungen von der dezentralen Strommesseinheit und dem dezentralen Spannungserfassungsmittel an die dezentrale Auswertungseinheit,
• e) Ermitteln von Nulldurchgängen der Spannung aus dem Spannungsverlauf in der dezentralen Auswertungseinheit,
• f) Bereitstellen einer gerechneten Sinuskurve auf Basis der ermittelten Nulldurchgänge durch die dezentrale Auswertungseinheit,
• g) Zuordnen der Augenblickswerte des Stroms zu den Werten der gerechneten Sinuskurve der Spannung durch die dezentrale Auswertungseinheit,
• h) Bilden normativer Augenblickswerte der Leistung aus den Augenblickswerten des Stroms und den zugeordneten Werten der gerechneten Sinuskurve durch die dezentrale Auswertungseinheit,
• i) Bilden eines normativen Leistungszwischenwertes aus den normativen Augenblickswerten der Leistung und Bereitstellen des Leistungszwischenwertes als Leistungszwischenwert durch die dezentrale Auswertungseinheit,
• j) Abfragen des Spannungswertes und des Leistungszwischenwertes des Stroms durch die zentrale Steuer- und Auswertungseinheit über die Verbindungen und Übertragen des Spannungswertes von der zentralen Spannungsmesseinheit und des Leistungszwischenwertes von der dezentralen Auswertungseinheit über die Verbindungen an die zentrale Steuer- und Auswertungseinheit,
• k) Berechnen der elektrischen Wirkleistung aus dem Spannungswert und dem Leistungszwischenwert durch die zentrale Steuer- und Auswertungseinheit.

The method according to the invention comprises the following method steps:

• a) measuring a voltage value by the central voltage measuring unit,
• b) measuring instantaneous values of the current through the distributed current measuring unit,
• c) detecting a voltage profile by the decentralized voltage detection means,
• d) transmitting the instantaneous values of the current and of the detected voltage profile via the connections from the decentralized current measuring unit and the decentralized voltage detection means to the decentralized evaluation unit,
• e) determining zero crossings of the voltage from the voltage profile in the decentralized evaluation unit,
• f) providing a calculated sinusoid on the basis of the determined zero crossings by the decentralized evaluation unit,
• g) assigning the instantaneous values of the current to the values of the calculated sinusoid of the voltage by the decentralized evaluation unit,
• h) forming normative momentary values of the power from the instantaneous values of the current and the assigned values of the calculated sine curve by the decentralized evaluation unit,
• i) forming a normative power intermediate value from the normative instantaneous values of the power and providing the intermediate power value as an intermediate power value by the decentralized evaluation unit,
• j) querying the voltage value and the intermediate power value of the current by the central control and evaluation unit via the connections and transmitting the voltage value from the central voltage measurement unit and the intermediate power value from the decentralized evaluation unit via the connections to the central control and evaluation unit;
• k) calculating the effective electrical power from the voltage value and the intermediate power value by the central control and evaluation unit.

In the first method step a), a voltage value is measured by the central voltage measuring unit.

The measurement of the voltage value is carried out either analog or digital, wherein it is according to the invention only necessary to measure an effective value of the voltage.

In the further method step b), an instantaneous value of the current is measured by the decentralized current measuring unit, wherein the measuring is preferably carried out in time parallel to the measurement of the voltage value in method step a).

In addition, in method step c), a voltage curve is detected at the respective consumer by the decentralized voltage detection means.

The measured instantaneous values of the current and the detected voltage profile are transmitted in step d) from the decentralized current measuring unit and the decentralized voltage detection means to the decentralized evaluation unit.

According to the invention, it is not absolutely necessary for the instantaneous values of the current and the voltage profile to be simultaneously transmitted to the decentralized evaluation unit.

Rather, in the present case, a time-shifted transmission of the instantaneous values of the current and of the voltage curve is also possible.

After the detected voltage curve has been transmitted to the decentralized evaluation unit, it then performs in process step e) a determination of zero crossings of the voltage applied to the respective load from the voltage curve and in step f) providing a calculated sinusoid on the basis of the determined zero crossings ,

The method steps b) to f) are according to the invention not determined in a chronological order, as that also first detecting and transmitting the voltage waveform according to the method steps c) and d) and a zero crossing detection according to method step e) and the provision of the calculated sinusoid according to method step f) can be carried out and subsequently only the measurement and the transmission of the instantaneous values of the current according to the method steps b) and d) are performed.

After both the instantaneous values of the current and the voltage profile have been transmitted to the decentralized evaluation unit, this is used in method step g) to assign the instantaneous values of the current to the values of the calculated sinusoid of the voltage.

From the instantaneous values of the current and the associated values of the sine curve of the voltage, normative instantaneous values of the load of the load are formed in method step h) by the decentralized evaluation unit, wherein the normative instantaneous values of the power are based on the calculated sine values, which according to the invention is based on a voltage to be arbitrarily defined , yet have no conclusive exactness and therefore have only normative character.

Subsequently, in method step i), a normative intermediate power value is formed in the decentralized evaluation unit from the normative instantaneous values of the power and the intermediate power value is provided as a power intermediate value for transmission to the central control and evaluation unit.

The intermediate power value is in this case formed by the integral of the normative instantaneous values of the power.

The voltage value measured by the central voltage measuring unit and the intermediate power value determined by the decentralized evaluation unit are transmitted to the central control and evaluation unit in method step j). It is according to the invention not necessary that the voltage value and the intermediate power value are simultaneously transferred to the central control and evaluation unit.

Rather, it is possible in this context to carry out a time-shifted transmission of these two values.

Further, the intermediate power value is preferably associated with an identifier which allows identification of the respective consumer belonging to the intermediate power value.

In the concluding method step k), the central control and evaluation unit calculates the exact electrical active power of the load from the voltage value and the intermediate power value. In the present case, the exact active electrical power is preferably calculated by multiplying the intermediate power value by a corresponding correction value, the correction value representing a value for the deviation of the voltage value, determined by the central voltage measuring unit, from a normative voltage value of the calculated sinusoid of the voltage.

In a particularly advantageous further development of the method, memory elements are assigned to the central voltage measuring unit and / or the decentralized units, wherein after method step a) an additional method step a1) and after method step i) an additional method step i1) can be carried out and wherein in method step a1) an intermediate storage the measured voltage value and in Process step i1) an intermediate storage of the determined intermediate power value in the respective memory element.

Furthermore, an advantageous variant of the method provides that a decentralized unit is designed as a decentralized master unit, wherein the connection between at least one decentralized unit with the central control and evaluation unit indirectly via the decentralized master unit and wherein the decentralized master unit with the at least one decentralized Unit is connected via a connection and that the method steps a) to i) are carried out both by the decentralized master unit and by the decentralized unit and that before the method step j) an additional method step i1) can be carried out in which a transmission of the formed Intermediate power value from the decentralized unit to the decentralized master unit. In addition, the method steps j) and k) are performed by the central control and evaluation unit for the power values of the decentralized unit and the decentralized master unit.

Furthermore, in a preferred embodiment of the method according to method step g), an additional method step g1) is carried out, wherein in method step g1), determining the phase values φ (phi) based on the assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage. is performed by the decentralized unit and wherein the phase angle φ (phi) is provided transferable or optionally outputable.

In addition, a particularly advantageous embodiment of the method provides that the decentralized unit in method step f) uses a rated voltage value for the calculated sinusoidal curve and that the central control and evaluation unit in method step k) corrects the intermediate power value on the basis of the central voltage measuring unit carried out voltage value.

As the underlying nominal voltage value, a value is preferably selected which approaches the nominal voltage applied to the consumer with sufficient accuracy, and thus an intermediate power value can be determined already in the decentralized unit, which approximates comparatively precisely to the actual value of the active power of the consumer.

In an advantageous development of the method, the measured voltage value in method step a) and the intermediate power value in method step i) are each assigned additional information about a detection time window, wherein in the case of the intermediate power value, the additional information about the detection time window relates to the instantaneous current values of the current.

Furthermore, in the development shown here, the central control and evaluation unit is able to determine the active electrical power in method step k) from a voltage value and an intermediate power value from matching acquisition time windows.

The particular advantage of this development is that, in particular with a provision of latches on the central voltage measuring unit and the respective decentralized unit, the respective voltage value and the respective intermediate power value not necessarily immediately after their measurement, or determination, to the central control and evaluation unit must be transferred.

Rather, it is possible in this context to provide the respective value with the additional information of the acquisition time window and to save this in the buffer.

Subsequently, a query of a plurality of stored voltage or power intermediate values can be carried out by the central control and evaluation unit, and then the relevant active power of the consumer can be determined from the values with the same acquisition time windows. The development thus enables a particularly exact determination of the active power, in particular for purposes of analyzing the operating behavior of consumers.

The invention will be described in embodiments by hand

1 Schematic representation with separate central voltage measuring unit

2 Schematic representation with integrated central voltage measuring unit

3 Schematic diagram with decentralized master unit explained in more detail.

1 shows in a schematic representation of a consumer 1 in an existing power grid 2 , In the present embodiment, it is in the power grid 2 a commercial three-phase AC circuit with three outer conductors L ₁ to L ₃ , a neutral conductor N and a central feed point 13 is.

An inventive system for determining the effective electrical power provides that to the existing power grid 2 a central control and evaluation unit 3 , a central voltage measuring unit 4 , a decentralized unit 5 comprising a distributed current measuring unit 6 with three current sensors 7 and a decentralized voltage detection means 8th as well as a decentralized evaluation unit 9 to be connected.

The connection of the system according to the invention takes place in such a way that the central voltage measuring unit 4 at a single defined feed-in point within the power grid 2 is connected and that the decentralized units 5 the respective consumer 1 is assigned, wherein each a current sensor 7 the decentralized current measuring unit 5 each one of the outer conductor L ₁ to L _{3 is} assigned.

The central voltage measuring unit 4 and the decentralized unit 5 are about connections 10 with the central control and evaluation unit 3 connected, wherein both the voltage measuring unit 4 as well as the decentralized unit 5 each memory elements 12 assigned.

The connections 10 between the central voltage measuring unit 4 , the decentralized unit 5 and the central control and evaluation unit 3 in the present case are modulated on the power grid 2 or realized by wireless connections.

Alternatively, the compounds 10 realized by means of a network, in particular LAN.

In the embodiment shown here are the voltage measuring unit 4 and the associated memory element 12.1 as structural of the control and evaluation unit 3 separated and thus as separate components.

2 shows an identical power grid 2 with a consumer 1 and a system according to the invention for determining the active electrical power.

In contrast to the embodiment in 1 lie the central voltage measuring unit 4 and the associated memory element 12.1 but not as separate components, but in the central control and evaluation unit 3 integrated.

By means of this integration, on the one hand the installation effort for a system according to the invention can be reduced, on the other hand, in this case, the connection between the central voltage measuring unit 4 and the central control and evaluation unit 3 via an internal processor bus (not shown) of the control and evaluation unit 3 educated.

In addition, shows 3 a preferred embodiment of the system according to the invention, in which a decentralized unit as a decentralized master unit 5.1 is trained.

The decentralized master unit 5.1 is present with other decentralized units 5 as well as with the central control and evaluation unit 3 connected, so that the connection of other decentralized units 5 with the central control and evaluation unit 3 indirectly via the decentralized master unit 5.1 consists. The in the decentralized units 5 In this embodiment, the intermediate power values determined are first sent to the decentralized master unit 5.1 and then from this to the central control and evaluation unit 3 transfer.

At the same time, the decentralized master unit 5.1 also able to determine performance intermediate values for their part and to transfer these to the central control and evaluation unit.

The connection between the decentralized master unit 5.1 and the other decentralized units 5 In this case, it is designed so that every further decentralized unit 5 with the decentralized master unit 5.1 connected is.

Alternatively, there is the possibility that the other decentralized units 5 , for example, within a BUS system, and thus the respective intermediate power values of a decentralized unit 5 via another decentralized unit 5 looped through and on this way to the decentralized master unit 5.1 be transmitted.

• a) Messen eines Spannungswertes durch die zentrale Spannungsmesseinheit 4, a1) Zwischenspeichern des Spannungswertes in dem Speicherelement 12.1,
• b) Messen von Augenblickswerten des Stroms durch die dezentrale Strommesseinheit 6, wobei die Stromwerte für jeden Leiter L₁ bis L₃ durch den jeweiligen Stromsensor 7 erfasst werden,
• c) Erfassen eines verbrauchernahen Spannungsverlaufs durch das dezentrale Spannungserfassungsmittel 8,
• d) Übertragen der Augenblickswerte des Stroms und des erfassten Spannungsverlaufs über die Verbindungen 11 von der dezentralen Strommesseinheit 6 und dem dezentralen Spannungserfassungsmittel 8 an die dezentrale Auswertungseinheit 9,
• e) Ermitteln von Nulldurchgängen der Spannung aus dem Spannungsverlauf in der dezentralen Auswertungseinheit 9,
• f) Bereitstellen einer gerechneten Sinuskurve auf Basis der ermittelten Nulldurchgänge durch die dezentrale Auswertungseinheit 9,
• g) Zuordnen der Augenblickswerte des Stroms zu den Werten der gerechneten Sinuskurve der Spannung durch die dezentrale Auswertungseinheit 9, g1) Ermitteln eines Phasenwinkels φ (phi) anhand der Zuordnung der Augenblickswerte des Stroms zu den Werten der gerechneten Sinuskurve der Spannung, durch die dezentrale Einheit 5 und Ausgeben des Phasenwinkels als Wert cos φ über die Ausgabevorrichtung 14,
• h) Bilden normativer Augenblickswerte der Leistung aus den Augenblickswerten des Stroms und den zugeordneten Werten der gerechneten Sinuskurve durch die dezentrale Auswertungseinheit 9,
• i) Bilden eines normativen Leistungszwischenwertes aus den normativen Augenblickswerten der Leistung und Bereitstellen des Leistungszwischenwertes als Leistungszwischenwert durch die dezentrale Auswertungseinheit 9, i1) Zwischenspeichern des Leistungszwischenwertes in dem Speicherelement 12.2,
• j) Abfragen des Spannungswertes und des Leistungszwischenwertes des Stroms durch die zentrale Steuer- und Auswertungseinheit 3 über die Verbindungen 10 und Übertragen des Spannungswertes und des Leistungszwischenwertes von den Speicherelementen 12 der zentralen Spannungsmesseinheit 4 und der dezentralen Einheit 5 über die Verbindungen 10 an die zentrale Steuer- und Auswertungseinheit 3,
• k) Berechnen der elektrischen Wirkleistung aus dem Spannungswert und dem Leistungszwischenwert durch die zentrale Steuer- und Auswertungseinheit 3.

With the presented exemplary embodiments, a method according to the invention for determining the active electrical power is carried out as an electrical parameter in the sequence described below, the following method steps being carried out in the present case:

• a) measuring a voltage value by the central voltage measuring unit 4 , a1) buffering the voltage value in the memory element 12.1 .
• b) measuring instantaneous values of the current through the distributed current measuring unit 6 , wherein the current values for each conductor L ₁ to L ₃ by the respective current sensor 7 be detected
• c) detecting a near-consumer voltage waveform by the decentralized voltage detection means 8th .
• d) transmitting the instantaneous values of the current and the detected voltage profile across the connections 11 from the decentralized current measuring unit 6 and the decentralized Voltage detection means 8th to the decentralized evaluation unit 9 .
• e) determining zero crossings of the voltage from the voltage curve in the decentralized evaluation unit 9 .
• f) providing a calculated sinusoid on the basis of the determined zero crossings by the decentralized evaluation unit 9 .
• g) assigning the instantaneous values of the current to the values of the calculated sinusoid of the voltage by the decentralized evaluation unit 9 , g1) determining a phase angle φ (phi) based on the assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage, by the decentralized unit 5 and outputting the phase angle as the value cos φ via the output device 14 .
• h) forming normative instantaneous values of the power from the instantaneous values of the current and the assigned values of the calculated sinusoidal curve by the decentralized evaluation unit 9 .
• i) forming a normative power intermediate value from the normative instantaneous values of the power and providing the intermediate power value as an intermediate power value by the decentralized evaluation unit 9 , i1) latching the intermediate power value in the memory element 12.2 .
• j) querying the voltage value and the intermediate power value of the current through the central control and evaluation unit 3 about the connections 10 and transmitting the voltage value and the intermediate power value from the memory elements 12 the central voltage measuring unit 4 and the decentralized unit 5 about the connections 10 to the central control and evaluation unit 3 .
• k) calculating the effective electrical power from the voltage value and the intermediate power value by the central control and evaluation unit 3 ,

In the first method step a) takes place according to the invention by the central voltage measuring unit 4 a measuring one, in the power grid 2 present voltage value, which subsequently in method step a1) in the, the central voltage measuring unit 4 associated, memory element 12.1 is cached.

Preferably, parallel to the measurement of the voltage value by the central voltage measuring unit 4 in method step b) measuring instantaneous values of the current through the current sensors 7 the decentralized current measuring unit 6 ,

Furthermore, in process step c), a consumer-oriented voltage profile is detected by the decentralized voltage detection means 8th , The method step c) is preferably carried out simultaneously with the method step b) in the present embodiment.

The detected instantaneous values of the current and the detected voltage profile are in the further method step d) via the compounds 11 from the decentralized current measuring unit 6 , or the decentralized voltage detection means 8th to the decentralized evaluation unit 9 transfer.

The decentralized evaluation unit 9 Now performs in step e) determining zero crossings of the voltage from the transmitted voltage curve and provides in step f) a calculated sinusoid of the voltage on the basis of the determined zero crossings ready.

The values resulting from the calculated sinusoid are then assigned the instantaneous values of the current determined in method step g), and the phase angle φ is determined on the basis of this assignment in method step g1). This phase angle φ is continued as the value cos φ via the output device 14 output.

The output device 14 is presently designed as a display device, in particular as a display.

Parallel to step g1) are by the decentralized evaluation unit 9 in method step h), normative instantaneous values of the power are formed from the instantaneous values of the current and the assigned values of the calculated sinusoid of the voltage.

Subsequently, the decentralized evaluation unit forms 9 in method step i) from the normative instantaneous values of the power, a normative intermediate power value, which in the subsequent method step i1) in the, the decentralized unit 5 associated, memory element 12.2 is cached.

Further, then, in method step j), the voltage value and the intermediate power value of the current are queried by the central control and evaluation unit 3 about the connections 10 and transmitting the voltage value and the intermediate power value from the memory elements 12 the central voltage measuring unit 4 and the decentralized unit 5 about the connections 10 to the central control and evaluation unit 3 , Insofar as a decentralized unit, as in 3 shown as a decentralized master unit 5.1 is formed, the power intermediate value first from the other decentralized units 5 at the decentralized master unit 5.1 and then from this to the central control and evaluation unit 3 transfer.

The central control and evaluation unit 3 is now able, in the final method step k), to calculate the voltage value and the intermediate power value by multiplying the intermediate power value by a corresponding correction value, the correction value in this case being a value for the deviation of the voltage value, determined by the central voltage measuring unit, from a normative voltage value represents the calculated sinusoid of the voltage, the electrical active power of the consumer 1 to calculate and output this, for example via a display (not shown). Alternatively, the calculated active power value can also be determined by the central control and evaluation unit 3 be provided transferable for further processing.

LIST OF REFERENCE NUMBERS

1

consumer

2

power grid

3

Central control and evaluation unit

4

central voltage measuring unit

5

decentralized unit

5.1

decentralized master unit

6

decentralized current measuring unit

7

current sensor

8th

decentralized voltage sensing means

9

decentralized evaluation unit

10

Connections to central control and evaluation unit

11

Connections to decentralized evaluation unit

12

storage element

13

central entry point

14

output device

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19827345 B4 [0009]
• DE 102011107932 B3 [0015]

Claims (18)

System for determining electrical characteristics of consumers ( 1 ) in a branched power grid ( 2 ), comprising a central control and evaluation unit ( 3 ), a central voltage measuring unit ( 4 ), as well as a plurality of decentralized units ( 5 ), each having a distributed current measuring unit ( 6 ) with at least one current sensor ( 7 ), a decentralized voltage sensing device ( 8th ) and a decentralized evaluation unit ( 9 ), whereby the decentralized units ( 5 ) to consumers ( 1 ), the central control and evaluation unit ( 3 ) via connections ( 10 ) with the central voltage measuring unit ( 4 ) and with the decentralized units ( 5 ), whereby the central voltage measuring unit ( 4 ) a voltage value is measurable and is provided transferable, and wherein the decentralized evaluation unit ( 9 ) via connections ( 11 ) with the decentralized current measuring unit ( 6 ) and the decentralized voltage detection means ( 8th ) is connected, whereby by the decentralized current measuring unit ( 6 ) Instantaneous values of a current are measurable and can be transmitted in a transferable manner, and wherein the decentralized voltage detection means ( 8th ) a voltage profile can be detected and provided in a transferable manner, and wherein the transmission of the instantaneous values of the current and of the detected voltage profile through the connections ( 11 ) from the decentralized current measuring unit ( 6 ) and the decentralized voltage detection means ( 8th ) to the decentralized evaluation unit ( 9 ), and wherein the decentralized evaluation unit ( 9 ) performs a zero-crossing determination of the voltage from the voltage curve, wherein based on the determined zero crossings, a calculated sinusoid of the voltage is provided, and wherein the decentralized evaluation unit ( 9 ) makes an assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage, whereby normative instantaneous values of the power are formed from the instantaneous values of the current and the respectively assigned values of the calculated sinusoid of the voltage, and from the normative instantaneous values of the output a normative intermediate power value is provided and transferable as an intermediate power value, and wherein the intermediate power value over the connection ( 10 ) from the decentralized evaluation unit ( 9 ) to the central control and evaluation unit ( 3 ), and wherein the central control and evaluation unit ( 3 ) performs a query of the voltage value and the intermediate power value, and wherein the central control and evaluation unit ( 3 ) from the voltage value and the intermediate power value, the electrical active power of the respective consumer ( 1 ). System according to claim 1, wherein the central tension measuring unit ( 4 ) and / or the decentralized units ( 5 ) Memory elements ( 12 ), by which the measured voltage value and the determined power intermediate value can be buffered. System according to claim 1 or 2, wherein the compound ( 10 ) of the central control and evaluation unit ( 3 ) with the central voltage measuring unit ( 4 ) and the decentralized units ( 5 ) by modulation on the power grid ( 2 ) he follows. System according to claim 1 or 2, wherein the compound ( 10 ) of the central control and evaluation unit ( 3 ) with the central voltage measuring unit ( 4 ) and the decentralized units ( 5 ) is formed wirelessly. System according to claim 1 or 2, wherein the central tension measuring unit ( 4 ) into the central control and evaluation unit ( 3 ) is integrated. System according to claim 5, wherein the compound ( 10 ) of the central control and evaluation unit ( 3 ) with the central voltage measuring unit ( 4 ) via an internal processor bus. System according to one of the preceding claims, wherein a decentralized unit as a decentralized master unit ( 5.1 ) and wherein the connection between at least one further decentralized unit ( 5 ) with the central control and evaluation unit ( 3 ) indirectly via the decentralized master unit ( 5.1 ) and whereby the decentralized master unit ( 5.1 ) with the at least one further decentralized unit ( 5 ) is connected via a connection and wherein the intermediate values of the at least one further decentralized unit ( 5 ) to the decentralized master unit ( 5.1 ) and wherein the intermediate values of the at least one further decentralized unit ( 5 ) in the decentralized master unit ( 5.1 ) be made available transferable. System according to one of the preceding claims, wherein the decentralized unit ( 5 ) is able, on the basis of the assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage, to determine a phase angle φ (phi) and to provide transferable or optionally outputable. System according to one of the preceding claims, wherein the decentralized unit ( 5 ) for the calculated sine curve is based on a nominal voltage value and wherein in the central control and evaluation unit ( 3 ) a correction of the intermediate value of the current can be carried out on the basis of the voltage value transmitted by the central voltage measuring unit. System according to one of the preceding claims, wherein the decentralized voltage detection means ( 8th ) through the current sensor ( 7 ) of the decentralized current measuring unit ( 5 ) is formed and wherein a capacitive on the current sensor ( 7 ) coupled voltage signal from the decentralized evaluation unit ( 9 ) can be evaluated as a voltage curve. System according to one of the preceding claims, wherein of the central tension measuring unit ( 4 ) the voltage value additional information about a detection time window of the voltage value can be assigned and is provided transferable and wherein by the decentralized unit ( 5 ) the intermediate power value additional information about a detection time window of the underlying instantaneous values of the stream is assigned and is provided transferable and wherein the central control and evaluation unit ( 3 ) determines the effective electrical power from a voltage value and an intermediate power value from matching acquisition time windows. System for determining electrical characteristics of a consumer ( 1 ) in a branched power grid ( 2 ), formed by a decentralized unit ( 5 ), comprising a distributed current measuring unit ( 6 ) with at least one current sensor ( 7 ), a decentralized voltage sensing device ( 8th ) and a decentralized evaluation unit ( 9 ), whereby the decentralized unit ( 5 ) each to the consumer ( 1 ), and wherein the decentralized evaluation unit ( 9 ) via connections ( 11 ) with the decentralized current measuring unit ( 6 ) and the decentralized voltage detection means ( 8th ) is connected, whereby by the decentralized current measuring unit ( 6 ) Instantaneous values of a current are measurable and can be transmitted in a transferable manner, and wherein the decentralized voltage detection means ( 8th ) a voltage profile can be detected and provided in a transferable manner, and wherein the transmission of the instantaneous values of the current and of the detected voltage profile through the connections ( 11 ) from the decentralized current measuring unit ( 6 ) and the decentralized voltage detection means ( 8th ) to the decentralized evaluation unit ( 9 ), and wherein the decentralized evaluation unit ( 9 ) performs a zero-crossing determination of the voltage from the voltage curve, wherein based on the determined zero crossings, a calculated sinusoid of the voltage is provided, and wherein the decentralized evaluation unit ( 9 ) makes an assignment of the instantaneous values of the current to the values of the calculated sinusoid of the voltage, whereby normative instantaneous values of the power are formed from the instantaneous values of the current and the respectively assigned values of the calculated sinusoid of the voltage, and from the normative instantaneous values of the output a normative intermediate power value of the consumer is made available and distributable. Method for determining electrical characteristics of consumers ( 1 ) in a branched power grid ( 2 ), by means of a central control and evaluation unit ( 3 ), by means of a central voltage measuring unit ( 4 ) and by means of a plurality of decentralized units ( 5 ), the central control and evaluation unit ( 3 ) via connections ( 10 ) with the central voltage measuring unit ( 4 ) and the decentralized units ( 5 ) and where the decentralized units ( 5 ) to consumers ( 1 ) are assigned and in each case a decentralized current measuring unit ( 6 ) with at least one current sensor ( 7 ), a decentralized voltage sensing device ( 8th ) and a decentralized evaluation unit ( 9 ), wherein the respective decentralized evaluation unit ( 9 ) via connections ( 11 ) with the respective decentralized current measuring unit ( 6 ) and the respective decentralized voltage detection means ( 8th ), comprising the following method steps: a) measuring a voltage value by the central voltage measuring unit ( 4 ), b) measuring instantaneous values of the current through the distributed current measuring unit ( 6 ), c) detecting a voltage profile by the decentralized voltage detection means ( 8th ), d) transmitting the instantaneous values of the current and of the detected voltage profile across the connections ( 11 ) from the decentralized current measuring unit ( 6 ) and the decentralized voltage detection means ( 8th ) to the decentralized evaluation unit ( 9 ), e) determining zero crossings of the voltage from the voltage curve in the decentralized evaluation unit ( 9 f) providing a calculated sine curve on the basis of the determined zero crossings by the decentralized evaluation unit ( 9 g) assigning the instantaneous values of the current to the values of the calculated sinusoid of the voltage by the decentralized evaluation unit ( 9 h) forming normative momentary values of the power from the instantaneous values of the current and the assigned values of the calculated sine curve by the decentralized evaluation unit ( 9 i) forming a normative power intermediate value from the normative instantaneous values of the power and providing the intermediate power value by the decentralized evaluation unit ( 9 ) j) querying the voltage value and the intermediate power value of the current by the central control and evaluation unit ( 3 ) over the connections ( 10 ) and transmitting the voltage value and the intermediate power value from the central voltage measurement unit ( 4 ) and the decentralized evaluation unit ( 9 ) over the connections ( 10 ) to the central control and evaluation unit ( 3 ), k) calculating the effective electrical power from the voltage value and the intermediate power value by the central control and evaluation unit ( 3 ). The method of claim 13, wherein the central tension measuring unit ( 4 ) and / or the decentralized units ( 5 ) Memory elements ( 12 and after method step a) an additional process step a1) and after process step i) an additional process step i1) is feasible, wherein in process step a1) an intermediate storage of the measured voltage value and in process step i1) an intermediate storage of the determined intermediate power value in the respective Memory element ( 12 ) respectively. Method according to claim 13 or 14, wherein a decentralized unit ( 5 ) is designed as a decentralized master unit and wherein the connection between at least one decentralized unit ( 5 ) with the central control and evaluation unit ( 3 ) indirectly via the decentralized master unit and wherein the decentralized master unit with the at least one decentralized unit ( 5 ) is connected via a connection and wherein the method steps a) to i) in each case by both the decentralized master unit and by the decentralized unit ( 5 ) and wherein prior to method step j) an additional method step i1) can be carried out, in which a transmission of the intermediate power value formed by the decentralized unit ( 5 ) to the decentralized master unit and wherein the method steps j) and k) for the power values of the decentralized unit ( 5 ) and the decentralized master unit. Method according to one of Claims 13 to 15, it being possible to carry out an additional method step g1) after method step g), wherein in method step g1) determining the instantaneous values of the current relative to the values of the calculated sinusoid of the voltage, determining a phase angle φ (phi) through the decentralized unit ( 5 ) and wherein the phase angle φ is provided transferable or optionally outputable. Method according to one of claims 13 to 16, wherein the decentralized unit ( 5 ) in method step f) for the calculated sine curve is based on a nominal voltage value and wherein the central control and evaluation unit ( 3 ) in method step k) carries out a correction of the intermediate power value on the basis of the voltage value transmitted by the central voltage measuring unit. Method according to one of claims 13 to 17, wherein in method step a) the measured voltage value additional information on a detection time window is assigned and wherein in step i) the intermediate power value additional information on a detection time window of the underlying instantaneous values of the stream can be assigned and wherein the central control and evaluation unit ( 3 ) in method step k) from a voltage value and an intermediate power value from the matching detection scope star determines the effective electrical power.

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