Determination of electrical energy flow

Abstract

The invention relates to a method and a device (6) for determining an electrical energy flow in an electrical conductor (con) by means of a contactless current measuring means (4) and a contactless voltage measuring means (2) and a measurement signal processing means (cal) which is designed to derive an electrical power (u * i) and / or an energy (suma u * i dt) from a measured current value (1) and a measured voltage value (u). In this case, at least one of the contactless measuring devices has an electromagnetic field shield (EMC). By means of the spacer (11), the device (6) is arranged in a galvanically isolated manner on the electrical conductor (con) to be measured.

Description

Field of the Invention

[0001] The present invention relates to a method for determining the electric power flow and / or energy flow through an electrical conductor, wherein at one location, two physical variables, namely current and voltage, are simultaneously determined and therefrom the electric power and / or electric energy are derived. Furthermore, the present invention relates to a device for determining the electric power flow and / or energy flow. Background Art

[0002] Precisely determining the electric energy flow and energy consumption is an important task for different application fields, such as industrial automation, building technology, and large-scale power distribution networks. Especially in the process of gradually transitioning to renewable energy and the decentralization of energy production, being able to dynamically analyze the electric energy flow in the future will be of decisive significance.

[0003] To determine the electric energy flow, two physical variables, namely current and voltage, must be measured simultaneously at the same location, i.e., on the same line section. Different measurement methods are provided for current measurement and voltage measurement. So far, energy measurement is preferably carried out using devices inserted into existing power connections, such as wires or power cables.

[0004] This is necessary because the voltage measurement that has been proven effective so far is carried out by contact methods in most cases, such as using analog-to-digital converters. For direct measurement in a circuit, contact methods require physical contact with the measurement object. Therefore, for this purpose, a permanently integrated measurement device needs to be used, or alternatively, the insulation of the power line to be measured must be interrupted, i.e., damaged. This necessary direct physical contact with the current-carrying line, especially in existing systems ("brownfield"), has the disadvantage that these devices must be temporarily separated from the power grid for measurement or installation and strict safety requirements regarding electrical safety must be strictly observed during subsequent operations. Current isolation must also be achieved for data transmission.

[0005] Although non-contact methods, such as Hall sensors or Rogowski coils, can also be used for current measurement, the combination of current measurement and voltage measurement for determining electric power or energy still poses challenges for non-contact voltage measurement so far.

[0006] A method for contactless voltage measurement is known from the prior art, for example from DE 10 2010 035 381 A1 and DE 10 2008 052 477 A1: The principle of a MEMS (microelectromechanical system) voltmeter, also known as a micromachined field mill, is based on measuring the time variation of a capacitance by means of a microelectromechanical system. The change of the capacitance over time is mechanically caused by electrical, electrostatic or thermal actuators. To measure the change in capacitance, the displacement current is detected via a current-voltage converter and a measurement signal is generated therefrom. By having the voltage contain a constant part and sampling the current-voltage converter during the switching edges of the voltage, the influence of the voltage to be measured on the measurement result is eliminated. This situation can mask the impulse response to a voltage change in the voltage to be measured, which voltage change also acts on the measuring capacitor. Utilizing the property of the capacitance measurement principle that a signal can only be detected when charge moves on the capacitor and a displacement current I(t) is caused. For this, the equation I(t) = dC / dt·U + dU / dt·C applies, where C is the capacitance of the capacitor and U is the voltage applied to the capacitor. According to DE 102010035 381 A1 and DE 10 2008 052 477 A1, the capacitance of the capacitor or the capacitance between a measurement object, such as a current-carrying conductor and a sensor, i.e., the MEMS voltmeter, can be changed by changing the area of the capacitor plates, in particular by inserting a partition into the capacitor gap, by changing the distance between the capacitor plates or by changing the relative permittivity of the medium located between the plates. Summary of the Invention

[0007] Based on the above prior art, the object of the present invention is to provide a method and a device for contactless determination of the electric power flow and / or the energy flow.

[0008] This object is achieved by the features of independent claim 1 and by the features of independent claim 5. Improved embodiments of the invention are the subject matter of the dependent claims.

[0009] The method for contactless determination of electric power and / or electric energy according to the invention includes a measurement signal processing step in which the electric power and / or energy is derived from the measured current value and voltage value. Here, the device according to the invention is first arranged in a current-isolated manner with respect to the electric conductor to be measured. The current is measured on the electric conductor by means of a first sensor by determining the magnetic field emitted from the current-carrying conductor, while the voltage is measured on the electric conductor by means of a second sensor by determining the electric field emitted from the current-carrying conductor, and the two measurement signals are compensated for each other in an analog manner by means of a circuit and / or in a digital data processing step. The term "in a current-isolated manner" should be understood to mean that although there are potential effects in the form of an electric field and a magnetic field due to the current flow, there is electrical insulation such that no current flows between the conductor to be measured and the device. Here, this arrangement is conveniently achieved by means of a spacer, for example via a mechanical mounting device or via a measurement-technically determined positioning, especially also without a structural connection to the conductor to be measured. The key advantage of this situation is that existing systems, such as brownfield systems, can be renovated without structural intervention.

[0010] Preferably, in the method for contactless determination of electric power and / or energy according to the invention, the voltage measurement is carried out by means of a MEMS voltmeter.

[0011] In a particularly advantageous variant of this method, the device is arranged in a current-isolated manner with respect to the electric conductor to be measured at a presettable measurement distance by means of a spacer. This particularly allows a minimum distance of 100 μm and a maximum distance from the voltage level to be determined and other sources of interference. For this purpose, there is a spacer which can in particular also be implemented as a mounting device, a cable guide, a cable clamp or particularly advantageously already includes parts of the current sensor, especially a magnetic field concentrator. Alternatively, the spacer includes a distance sensor, whereby the measurement distance can be fixed.

[0012] In a further variant of this method, it includes at least one analog measurement signal preprocessing step at the sensor level, in which an analog signal output is generated in particular by means of an I / U converter, a high-pass filter, a low-pass filter and / or an amplifier.

[0013] The method according to the invention is particularly advantageous because it enables the determination of electric power and / or energy with a high time resolution. The measurement is carried out in particular at a sampling rate which is at least one order of magnitude higher than the frequency of the measurement signal. Measuring the two physical variables of current and voltage simultaneously means that the power value or energy value is also determined simultaneously on the board.

[0014] The device according to the invention comprises a contactless current measuring device and a contactless voltage measuring device, wherein at least one of the contactless measuring devices has an electromagnetic field shield, the device has a measuring signal processing device which is embodied to derive the electrical power P = u·i and / or the energy E = ∫u·i dt from the measured current and voltage values, and wherein the device comprises at least one spacer, in particular a mounting device, by means of which the device can be arranged on the electrical conductor to be measured in a manner electrically isolated from the current of the electrical conductor to be measured. The proposed solution combines two contactless measuring methods. The main advantage of the device is that two physical variables, namely current and voltage, are determined precisely, with high temporal resolution and simultaneously, at the same measuring point or measuring section of the electrical conductor to be measured and the electrical power or electrical energy is derived therefrom. Thus, an electrical component is proposed which solves two problems of power supply isolation and safety requirements by means of contactless methods.

[0015] Contactless measurement is to be understood as an indirect measurement of voltage or current without contact, i.e. without electrical potential. The energized measurement object generates an electric field. Based on the change of the measured capacitance over time, this electric field can be measured contactlessly. Contactless current measurement uses the magnetic field induced by moving charges as the physical measurement variable. By means of computer operation, the instantaneous power P = u·i in the current-carrying conductor or the time-integrated energy flow E = E = ∫u·i dt in the current-carrying conductor is determined. Due to the current isolation, there is no electrical contact and no intervention in the circuit during contactless measurement, which means that the insulation remains undamaged. The spacer can also very simply refurbish existing systems, such as so-called brownfield systems, without the need for intervention and can therefore also be digitized simply.

[0016] In a particularly preferred embodiment of the invention, the contactless voltage measuring device comprises a sensor for measuring the electric field strength. In particular, the voltage measuring device is designed as a MEMS voltmeter. This particularly brings the advantage that a very large voltage measurement range can be covered by MEMS voltmeter technology, from a single volt up to several thousand volts.

[0017] The principle of the MEMS voltmeter is based on the periodic shielding of two electrodes in an external electric field. Therefore, the voltage can be calculated when the capacitance of the electrodes is constant and the distance to the external potential is constant. "Analysis and Design of Micromechanical Electric Field Sensors" by Bahrenyni et al., published in the Journal of Microelectromechanical Systems, Vol. 17, No. 1, February 2008, pp. 31-36, generally describes that the electrometer is a common sensor for electric fields in the above application fields. The functional principle is based on a grounded switch that repeatedly shields the sensor electrode assembly from the field to be measured and then exposes the sensor electrode assembly to the field again. According to Gauss's law, we alternately discharge and charge (move current) the sensor electrode assembly behind the switch by induction of the external electric field. In the current case, a miniaturized device is proposed for this purpose.

[0018] In a further preferred design of the present invention, the device includes a current measuring device and a voltage measuring device, which are in two separate chip packages arranged on a common circuit carrier. In an alternative and equally advantageous design of the present invention, the device includes a current measuring device and a voltage measuring device, which are arranged on two separate sensor chips within a common chip package. And in a further alternative and equally advantageous design of the present invention, the device includes a current measuring device and a voltage measuring device, which are arranged on a common sensor chip, especially as an integrated electronic device. Here, the circuit carrier can be understood, for example, as a circuit board or an alternative base for electronic components. The sensor chip can especially be understood as a semiconductor substrate, a so-called die or wafer, which is not yet encapsulated differently from the chip package, that is, it is bare. The chip package is then correspondingly understood as a coated semiconductor chip, where the chip housing can here not only perform a protection function but also an installation and spacer function.

[0019] In all cases, two measurements are made from one board measurement, namely current and voltage measurements. Preferably, the two measuring devices are arranged a few centimeters apart, and this situation is understood as "the same position", "the same measurement point" or "measurement on the same line section". In this way, current and voltage measurements can be performed at the same position, and in particular, it is ensured by means of electromagnetic field shielding that there are no field influences here that could interfere with the measurement. Preferably, the measurements are also evaluated on the same board. Alternatively, multiple boards or circuit carriers are stacked.

[0020] In an advantageous variant of the device, the contactless current measurement device includes a Hall element. With the aid of a Hall sensor, direct current as well as alternating current can be measured. The Hall element is based on the measurement of the magnetic flux density. Even with a very small current of about 0.5 A and a simple silicon-based Hall sensor, a measurable Hall voltage of 10 mV can still be achieved. Usually, the Hall element includes a magnetic flux concentrator made of iron, the so-called IMC. Measurements can also be carried out using a so-called XMR sensor, in which there is a change in the resistance due to the magnetic flux. The XMR sensor is a sensor for magnetic flux density, especially a thin-film sensor that directly changes its resistance under the influence of magnetic flux. XMR sensors include, for example, GMR sensors, AMR sensors, or CMR sensors.

[0021] An alternative is the Rogowski coil for contactless current measurement. However, the Rogowski coil can only measure alternating voltages. The Hall element does not have this limitation.

[0022] In a further advantageous variant of the device, the measurement signal processing device is implemented to compensate two measurement signals, namely current and voltage, in an analog and / or digital manner. If the current and voltage are known, the values of power P = u·i and E = ∫u·i dt are simple calculation operations. The advantage of digital evaluation is that the individual values are then also in digital form.

[0023] In a further advantageous variant of the device, there is a signal preprocessing device at the level of the sensor, especially one of the two measuring devices, such as an I / U converter, a high-pass filter, a low-pass filter, and / or an amplifier, which outputs the analog signal to the measurement signal processing device.

[0024] Preferably, the device or the measurement signal processing device includes another signal processing device on a common circuit carrier or a stack of common circuit carriers. In particular, the device or the measurement signal processing device is implemented to communicate at the system level using the common circuit carrier. For example, the device has a connector, a plug, a data connector, or other interfaces for data output, thereby enabling communication with a data processing device, such as a computer. A computer can be understood, for example, as a personal computer, a server, a handheld computer system, a palmtop computer device, a mobile radio device, an edge device, and other communication devices, processors, and other electronic devices capable of computer-aided data processing.

[0025] Suitably, the device or the measurement signal processing device has a bus system for combining measurement signals, especially for determining digital power values and / or energy values. Alternatively, the measurement signal processing device has an evaluation electronics for analog evaluation. Description of the Drawings

[0026] Additional features, characteristics, and advantages of the present invention are derived from the following description with reference to the attached Figures 1 to 13 drawings. The drawings show:

[0027] Figure 1 A schematic diagram showing the operating mode of a MEMS voltmeter.

[0028] Figure 2 A schematic diagram showing the measurement principle of an energy meter.

[0029] Figure 3 Measurement results from a MEMS voltmeter.

[0030] Figure 4 Simulation of a current-carrying conductor and a Hall element.

[0031] Figure 5 Schematic design diagram of a MEMS voltmeter.

[0032] Figure 6 A schematic diagram showing the measurement principle of an energy meter with an electromagnetic field shield.

[0033] Figure 7 Schematic diagram of the structure of an energy meter with cables arranged.

[0034] Figure 8 Schematic diagram of a cross-section of the housing of an energy meter.

[0035] Figure 9 Schematic diagram of the IMG of a Hall element as a cable clamp.

[0036] Figure 10 Schematic diagram of the measurement principle of a Hall element.

[0037] Figure 11 Shows a cross-section through the housing of the energy meter in Figure 9

[0038] Figure 12 Schematic diagram of an insulating spacer implemented as a cable sleeve.

[0039] Figure 13 Circuit diagram of an analog signal (pre)-processing device.

[0040] Figure 14 Schematic diagram of a spacer with a distance sensor. Detailed Description

[0041] In the embodiments and the drawings, identical or functionally identical elements can be provided with the same reference signs, respectively. The elements shown and their size relationships to one another are not considered to be to scale in principle; rather, the individual elements can be shown larger in scale for better visibility and / or for better clarity.

[0042] Figure 1 The operating mode of the MEMS voltmeter 2 is schematically shown: A measurement object 1 with voltage U generates an electric field E. This electric field E is measured contactlessly by means of the MEMS voltmeter 2. Figure 5 A schematic design of the MEMS voltmeter 2 is shown. It involves two electrically insulated capacitor plates sen, and the two capacitor plates are connected to each other via an amplifier circuit 23, see Figure 13 . An oscillating electrode sh at a neutral reference potential is arranged parallel to the plane of space on these capacitor plates sen or in the direction of the source of the electric field E to be measured. This oscillating electrode sh shields one of the two capacitor plates sen from the electric field E of the external electrical conductor con to be measured according to the deviation. With respect to the intensity of the external electric field E, a current flows during each oscillation path of the electrode sh. Here, the initial signs of the currents of the two capacitor plates are always opposite. The difference between these currents is proportional to the electric field E of the conductor con and can be measured by the amplifier circuit 23. This electric field E is in turn defined by the voltage U of the conductor con and the distance from the conductor con.

[0043] If this voltage measurement 2 is combined with a contactless current measurement 4 based on, for example, a magnetic field sensor, in particular a Hall sensor or a Rogowski coil, then the instantaneous power P in the conductor con or the time-integrated energy flow in the conductor con can be determined by means of a simple computer operation cal. The current measurement 4 uses the magnetic field B generated by moving charges as the physical measurement variable. The measurement principle of such an energy meter 6 is shown in Figure 2 : The simultaneous determination of current and voltage flow enables the calculation of the current power flow u·i in the conductor by simple multiplication of two values con, or the calculation of the energy flow ∫u·i through the conductor con by time integration.

[0044] The two sensors 2, 4 can be arranged in different ways. For example, the voltmeter 2 and the current sensor 4 can be monolithically arranged on a single semiconductor substrate. In another embodiment, the two sensor chips 2, 4 are arranged in a common chip package. In a third embodiment, two mutually independent chip packages are connected to a common circuit carrier boa.

[0045] Figure 3The measurement results of a MEMS voltmeter are shown as the amplitude difference Diff = Max - Min in digital codes output by an ADC according to the measured voltage U in volts and the distance d in millimeters between the sensor 2 and the wire con. The measured values show good linearity independent of the measurement distance d. Good response of the sensor 2 is shown for different voltages U and distances d between the sensor and the measurement line con.

[0046] In Figure 4 a simulation of a current-carrying conductor con and a Hall element HE with a magnetic flux concentrator IMC made of iron is shown. The arrows show the magnetic field strength or the magnetic flux density B in tesla in three spatial directions x, y, z. Comparison: In central European latitudes, the geomagnetic field has a magnetic flux density B of 48 μT. In an embodiment of a device according to the invention, such as an energy meter 6, the MEMS voltmeter 2 is coupled to the Hall sensor 4. The two measurement signals i, u are compensated cal for each other in analog and / or digital form.

[0047] Figure 5 A schematic design of the MEMS chip 2 is shown for the MEMS voltmeter component 2. Such a MEMS chip is used, for example, to implement measurements as shown in Figure 3 this.

[0048] Figure 6 The measurement principle of the energy meter 6 is schematically shown, with an electromagnetic field shield EMC for the voltage measuring device 2. Alternatively or additionally, the current measuring device 4 can also be surrounded by the electromagnetic field shield EMC. Alternatively or additionally, in an embodiment of the energy meter 6, the entire unit including the measuring devices 2, 4 and the evaluation units 23, cal has an electromagnetic field shield EMC.

[0049] Accordingly, the evaluation electronics 23, cal can be integrated on different levels. Thus, for example, a certain preprocessing 23 of the signals can be performed at the level of the sensors 2, 4, while the final processing can be carried out on a common circuit carrier boa. Communication is also carried out via this circuit carrier boa.

[0050] In an alternative embodiment of the device 6, the device can also capture the two measured variables u, i with a certain spatial separation, but on the same conductor. Then, for example, the measurement signals are combined via a bus system bus as shown in Figure 2 this. Subsequent processing cal is then carried out, for example, with the aid of a connected evaluation electronics or a digital evaluation device, such as a microprocessor.

[0051] Figure 7Schematically shows the structure of the energy meter 6, which has a sensor housing h and built-in electronics boa, cal, and is arranged using a cable con. Figure 8 Schematically shows a cross-section through the housing h of the energy meter 6. This shows a stack of circuit carriers consisting of a plurality of boards boa, which are connected via a circuit board connector 52. In addition, a connection cable or plug 5 is provided. Further electronic components 51 can be provided on the printed circuit board boa. The current measuring device 4 has a magnetic shield 41. This magnetic shield particularly includes a magnetic flux concentrator made of iron, a so-called IMC. However, the U-shaped flux concentrator is arranged here rotated by 90° relative to the conductor con.

[0052] In addition, the energy meter device 66 has, for example, an insulating spacer 11, which is also particularly used for locking onto the conductor con to be measured. The spacer 11, on the one hand, enables a current-isolated arrangement, and on the other hand, can set the distance d between the sensor 2, 4 and the field source con.

[0053] Figure 9 Schematically shows the flux concentrator IMG of the Hall element HE as a type of cable clamp. The corresponding measurement principle of the Hall element HE is shown schematically in Figure 10 An analog measurement signal is output, for example, via an amplifier 42. Such an amplifier 42 can, for example, be an analog measurement signal preprocessing device or be included therein.

[0054] Figure 11 Schematically shows as Figure 9 shown in the cross-section through the housing h of the energy meter 6. This figure again shows a stack of circuit carriers consisting of a plurality of boards boa, which are connected via a circuit board connector 52. In addition, a connection cable or plug 5 is provided. On the printed circuit board bo there are analog circuits 50 each having an EMC shield. These EMC shields can, for example, each be an analog measurement signal preprocessing device for current and voltage measuring devices. The current measuring device 4 has an annular flux concentrator IMG, which is arranged around the cable con to be measured. The voltage sensor 2 has an electromagnetic shield EMC, and the electromagnetic shield particularly also shields the two sensors 2, 4 from each other. The shields EMC, 50 for the evaluation electronics of the voltage sensor 2 are particularly important. However, the actual sensor 2 must remain exposed relative to the conductor con. It is advantageous if these evaluation electronics are located on the side of the board boa facing away from the conductor con to be measured, as also shown in Figure 11 as shown in.

[0055] Figure 12Schematically shows a possible embodiment of an insulating spacer 11, which is designed as a cable bushing. The spacer 11 includes an insulating spacer as a lower part 12 and an attachment to an energy meter device 6, as well as a pluggable or clip-on upper part 13 by means of which the cable con to be measured can be fixed. Such a cable bushing accordingly ensures a current-isolated arrangement.

[0056] Particular attention should also be paid to the influence of interference fields on the measurement. If, for example, measurements are carried out in a polyphase system, care should be taken to ensure that the phases not to be measured are shielded by a suitable conductive shield EMC and / or the distance d between the sensor 2 and the conductor con to be measured is less than the distance d between the conductor con and the interference field (e.g., caused by another conductor). Therefore, the device 6 is preferably also designed such that the input lines of the sensor 2, such as measurement lines and / or supply lines, are shielded from the external electric field in order to avoid interference coupling. In addition, the arrangement of the supply lines, for example, for the high-frequency excitation of the oscillating electrodes sh and the measurement lines must be selected appropriately in order to avoid crosstalk of the high-frequency excitation into the sensitive measurement channels.

[0057] Figure 13 Shows the circuit diagram of the analog signal (pre)-processing devices 23, 50. In this circuit diagram, it is shown highly simplified how the voltmeter part can be shielded. For example, in order to amplify two sensor paths, parts of the analog circuits 23, 50 are shielded, or even further include a differential amplifier, which outputs an analog signal 3. As shown in Figure 5 As shown, the actual MEMS components are, for example, arranged on the back side of the shield EMC or PCB, see the cross-section in Figure 11 The Hall sensors are also shielded in an analogous manner. However, preferably at least the voltmeter is shielded.

[0058] Figure 14 Is a schematic view of the spacer 11 with distance sensors. These distance sensors are particularly advantageous when measuring overhead lines and underground cables because no structural connection to the conductor con to be measured is required. If it is known exactly, it is also possible to operate without sensors.

[0059] Although the present invention has been shown and described in detail by preferred embodiments, the present invention is not limited by the disclosed examples. Those skilled in the art can derive variations therefrom without departing from the scope of protection of the present invention as defined by the following claims.

[0060] List of reference numerals

[0061] 1 Measuring voltage

[0062] 2 MEMS voltmeter, measuring device

[0063] sen sensor surface

[0064] sh switch, movable

[0065] act combined actuator

[0066] 21 I / U converter

[0067] 22 I / U converter

[0068] 3 Analog signal, signal output of voltage sensor

[0069] 4 Current sensor, such as Hall element HE bus data bus

[0070] cal Computer, evaluation unit

[0071] Int Result output: such as energy flow

[0072] h Sensor housing 5 with built-in electronics (boa, cal) Connecting cable, plug

[0073] 51 Additional electronic components

[0074] 52 Circuit board connector

[0075] 41 Magnetic shield, flux concentrator (IMC) (rotated 90° relative to conductor con) 11 Spacer

[0076] 12 Insulating spacer designed as cable sleeve

[0077] 13 Pluggable or clampable upper part

[0078] Unf(t) Useful signal to be modulated

[0079] Ut(t) Unmodulated carrier

[0080] Uam(t) Modulated carrier

[0081] U Voltage

[0082] t Time

[0083] f Frequency

[0084] ω Low frequency

[0085] Ω Carrier frequency

[0086] con Electrical conductor, such as cable

[0087] i Current with direction arrow

[0088] I Current

[0089] E Electric field strength

[0090] B [tesla], magnetic flux density d [mm] of the magnetic field induced by current i, distance from sensor LP

[0091] Diff, SENSE-Diff amplitude in ADC digits [maximum - minimum], x, y, z spatial directions

[0092] HE, Hall element

[0093] IMG, magnetic flux concentrator, e.g., IMC boa made of iron, circuit carrier, e.g., circuit board

[0094] 42, amplifier

[0095] 50, analog circuit with EMC shielding

[0096] 23, analog signal (pre)-processing device

[0097] EMC, electromagnetic shielding

Claims

1. A method for non-contact determination of electric power and / or energy, wherein, in a measurement signal processing step (cal), electric power (u·i) and / or energy (∫u·i dt) are derived from measured current values (i) and voltage values (u), wherein, - the device (6) is arranged in current isolation from the electrical conductor (con) to be measured, - a current measurement (i(t)) is performed on the electrical conductor (con) by means of a first sensor (4) by determining the magnetic field (B) emitted from the current-carrying conductor (con, i), - a voltage measurement (u(t)) is performed on the electrical conductor (con) by means of a second sensor (2) by determining the electric field (E) emitted from the current-carrying conductor (con, i) with the aid of a MEMS voltmeter (2), - and the two measurement signals (i, u) are compensated for each other by means of a circuit and / or in a digital data processing step (cal).

2. The method according to claim 1, wherein, the voltage measurement is performed such that the sensor electrode assembly is repeatedly shielded from the field (E) to be measured by means of a ground switch and then exposed again to the field (E) relative to the field (E), so that the sensor electrode assembly behind the switch is alternately discharged and charged by induction of the electric field (E) to be measured.

3. The method according to claim 1 or 2, wherein, the device (6) is arranged in current isolation from the electrical conductor (con) to be measured at a presettable measurement distance by means of a spacer (11).

4. The method according to any one of the preceding claims 1 to 3, comprising at least one analog measurement signal preprocessing step (23) at the level of the sensors (2, 4) by means of an I / U converter (21), a high-pass filter, a low-pass filter and / or an amplifier and outputting an analog signal.

5. A device (6) comprising a non-contact current measurement device (4) and a non-contact voltage measurement device (2), wherein, the non-contact voltage measurement device (2) comprises a sensor (sen) for measuring the electric field strength (E), and the non-contact voltage measurement device is in particular embodied as a MEMS voltmeter, and wherein at least one of the non-contact measurement devices has an electromagnetic field shield (EMC), the device has a measurement signal processing device (cal) which is embodied for deriving electric power (u·i) and / or energy (∫u·i dt) from measured current values (i) and voltage values (u), and wherein the device comprises at least one spacer (11) by means of which the device (6) can be arranged in current isolation from the electrical conductor (con) to be measured on the electrical conductor (con) to be measured.

6. The device (6) according to claim 5, wherein, The contactless voltage measuring device (2) is in particular embodied as a MEMS voltmeter, and the contactless voltage measuring device includes a sensor electrode assembly and a ground switch (sh), which is also embodied for repeatedly shielding the sensor electrode assembly from the field (E) to be measured and then exposing the sensor electrode assembly relative to the field (E). In particular, the sensor electrode assembly includes two capacitor plates (sen) that are electrically insulated from each other, and the capacitor plates are interconnected by an amplifier circuit (23), and preferably in the direction of the source of the electric field (E) to be measured. In particular, an oscillating electrode is arranged parallel to the capacitor plates (sen) in a spatial plane as the switch (sh), the oscillating electrode is at a neutral reference potential, and the oscillating electrode shields one of the two capacitor plates (sen) from the electric field (E) to be measured according to a deviation.

7. The device (6) according to any one of claims 5 or 6, wherein, the current measuring device (4) and the voltage measuring device (2) are arranged in two separate chip packages on a common circuit carrier (boa).

8. The device (6) according to any one of claims 5 or 6, wherein, the current measuring device (4) and the voltage measuring device (2) are arranged on two separate sensor chips within a common chip package.

9. The device (6) according to any one of claims 5 or 6, wherein, the current measuring device (4) and the voltage measuring device (4) are arranged on a common sensor chip.

10. The device (6) according to any one of claims 5 to 9, wherein, the contactless current measuring device (4) includes a Hall element (HE) or an XMR sensor.

11. The device (6) according to any one of claims 5 to 10, wherein, the measurement signal processing device (cal) is embodied for compensating the two measurement signals (u, i) for each other in an analog and / or digital manner.

12. The device (6) according to any one of claims 5 to 11, the device includes a signal preprocessing device (23) at the level of the sensors (2, 4), which is in particular embodied as an amplifier circuit, and the signal preprocessing device is used to measure the difference in the current that discharges and charges the capacitor plates (sen) during each oscillation path of the electrode (sh).

13. The device (6) according to any one of claims 5 to 12, wherein, the measurement signal processing device (cal) includes additional signal processing devices on a common circuit carrier (boa) or a stack of common circuit carriers.

14. The device (6) according to any one of claims 5 to 13, wherein, the measurement signal processing device (cal) is embodied for communicating at the system level by means of a common circuit carrier (boa).

15. The device (6) according to any one of claims 5 to 14, wherein, The measuring signal processing device (cal) has a bus system (bus) for combining the measuring signals (u, i) and a connector (5) for data output (Int).

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