EP3491398A1 - Device and method for measuring the strength of the current an individual conductor of a multi-conductor system - Google Patents

Device and method for measuring the strength of the current an individual conductor of a multi-conductor system

Info

Publication number
EP3491398A1
EP3491398A1 EP17765397.9A EP17765397A EP3491398A1 EP 3491398 A1 EP3491398 A1 EP 3491398A1 EP 17765397 A EP17765397 A EP 17765397A EP 3491398 A1 EP3491398 A1 EP 3491398A1
Authority
EP
European Patent Office
Prior art keywords
conductor
current
field
radius
circuit board
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP17765397.9A
Other languages
German (de)
French (fr)
Inventor
Jürgen Götz
Stefan Hain
Franz MEIERHÖFER
Roland Weiss
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Energy Global GmbH and Co KG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP3491398A1 publication Critical patent/EP3491398A1/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/207—Constructional details independent of the type of device used
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/10—Measuring sum, difference or ratio
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/04—Measuring direction or magnitude of magnetic fields or magnetic flux using the flux-gate principle
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/07—Hall effect devices

Definitions

  • the invention relates to a device and a method for measuring the current intensity of a single conductor of a multi ⁇ conductor system.
  • multi-conductor cables comprising at least two conductors are used. With multi-conductor cables, each conductor is isolated according to the voltage. All conductors are then typically stranded together and again covered with egg ⁇ nem common insulation material.
  • the measurement of the current flow in a single conductor of such a multi-conductor system can be effected by means of shunt resistors, toroidal transformers, Rogowski coils or with a field-probe-based sensor system.
  • the conductor to be measured must be accessible individually for a measurement, which often means that the multi-conductor cable has to be separated.
  • the measuring system comprises at least two field sensors which are arranged on a printed circuit board around the multi-conductor system.
  • the field sensors are suitable, a magnetic field resulting from a linear combination of the Mag ⁇ netfelder of each conductor to be measured and convert them into an electrical signal.
  • the measuring system also includes a signal evaluation device, by means of which the current in the current conductor is determined by means of the signals of the at least two field sensors and by at least a distance of the current ⁇ conductor to one of the field sensors.
  • this measuring system is sensitive to via external fields, whereby the measurement of the current flow in the conductor can be falsified.
  • the object is achieved with a device according to claim 1 and a method according to claim 10.
  • the device according to the invention for measuring a current intensity in a conductor of a multi-conductor system with at least two conductors comprises at least two field sensors.
  • Each field sensor is suitable to measure a magnetic field resulting from egg ⁇ ner linear combination of the magnetic fields of the individual conductors and convert it into an electrical signal.
  • a first field sensor is arranged on a first radius nikseg- element-like around the conductor and a second field ⁇ sensor is arranged on a second radius in a circle segment around the conductor, wherein the first radius is greater than the second radius.
  • the apparatus further comprises a signal evaluation device which is suitable for determining the current intensity in the current conductor by means of the difference of the signals of the at least two field sensors and by means of at least a first distance of the current conductor to the first field sensor or by means of a second distance of the current conductor to the second field sensor to investigate.
  • a signal evaluation device which is suitable for determining the current intensity in the current conductor by means of the difference of the signals of the at least two field sensors and by means of at least a first distance of the current conductor to the first field sensor or by means of a second distance of the current conductor to the second field sensor to investigate.
  • the first and the second field sensor are arranged on a common printed circuit board. All field sensors, ie both the field sensors on the first radius and the field sensors on the second radius, are arranged on the common printed circuit board and can be placed around the multi-conductor system and fixed. Thus, the rela ⁇ tive position and the distance of the field sensors to each other and to the current conductor to be measured during the measurement are constant. This advantageously allows constant measurements.
  • the first field sensor on a first circuit board and the second field sensor on a second Lei ⁇ terplatte are arranged.
  • the first and the second radius can be selected independently of each other.
  • the printed circuit board with the field sensors can thus be laid variably around the multi-conductor system.
  • the multi-conductor system can have different shapes, in particular circular or oval-shaped.
  • the scope of the multi-conductor system and the length of the first and / or second circuit board need not be exactly matched. It is advantageous sufficient if the printed circuit boards each ⁇ wells partially can be placed around the multi-conductor system around.
  • the flexible circuit board can be installed both on new multi-conductor systems, as well as already installed old systems. The fixation, for example, by flexible terminals, a Screwed or made by an adapter made to fit.
  • the number of field sensors on a printed circuit board is equal to or greater than the number of Stromlei ⁇ ter. It is advantageous possible for each individual conductors of multi-conductor system, the current strength during limited ⁇ men.
  • the field sensors have different distances to the current conductor to be measured. Since the magnetic field of a straight current-carrying conductor decreases reciprocally with the distance, it is then possible with the aid of a linear combination of the magnetic fields of the individual conductors to deduce the current intensity in a specific individual current conductor.
  • the number of field sensors on the first and second circuit board is the same.
  • a first and a second field sensor are then assigned to each other in pairs. The two sensors can then advantageously produce signals which are used to determine the
  • the ratio of the first radius to the second radius is in a range between 1.1 and 3.
  • the measuring signals of the first and second field sensors are sufficiently different in this area to exclude foreign fields from the measurement and on the other hand of the same order of magnitude in order to be able to calculate the current intensity.
  • the first field sensor and the second Field sensor radially aligned, that is arranged from a center of the multi-conductor system on a line.
  • the sensitive direction of the field sensors is aligned parallel to one another Wesentli ⁇ chen.
  • At least one of the field sensors is a fluxgate sensor or a Hall sensor.
  • a fluxgate sensor is understood to mean a sensor which represents a magnetometer for the vectorial determination of a magnetic field.
  • the fluxgate sensor is also called a forester probe. With fluxgate sensors it is possible to measure magnetic fields from 0, 1 nT to 5 mT.
  • a Hall sensor advantageously uses the Hall effect to measure magnetic fields.
  • a Hall sensor does not change the magnetic field to be measured, since no magnetically active materials have to be installed in Hall sensors.
  • the first and the second field sensor are arranged substantially planar to one another.
  • the first and the second circuit board are then also arranged substantially zuei ⁇ nander planar.
  • the sensitive direction of each ⁇ thro nozzle field sensors is aligned parallel to one another.
  • the printed circuit boards are arranged around the multi-conductor system such that the printed circuit boards are arranged with respect to their surface normal parallel to the axial direction of the multi-conductor cable. In this arrangement, the distance-of the first and second field sensor to each other and to the center of the multi-conductor system in the radial direction kon ⁇ constant.
  • the distance of the field sensors to the center of the system can be easily determined over the circumference, so that this distance is known.
  • This arrangement can thus advantageously ensure the necessary flexibility during the assembly ⁇ phase of the circuit board and continue to ⁇ advantageous to ensure the spatially fixed radial arrangement of the field sensors to each other and to be measured conductors during the measurement phase.
  • the length of the circuit board is selectable such that the multi-wire system is arranged in a circular segment-like Wenig ⁇ least 180 ° around the multi-conductor system around.
  • the circuit board can be arranged different multi ⁇ conductor systems with different circumferential lengths and circumferences around.
  • the signal evaluation device is arranged on the circuit board. It is advantageous for measuring the
  • a current egg nes current conductor in a multi-conductor system by means of the off ⁇ valuing at least two electrical signals from at least two field sensors is determined in a signal evaluation device. From a first signal, a first magnetic field strength is determined and from a second signal, a second magnetic field strength is determined. Furthermore, a first distance between the first field sensor and the current conductor is known, or a second distance between the second field sensor and the current conductor is known. By using the law of Biot-Savart the amperage of the Stromlei ⁇ ters is then determined from the difference of the first and second magnetic field strength and from the first or the second distance.
  • Figure 2 is a plan view of a multi-conductor system measuring apparatus
  • FIG. 3 shows a multi-conductor system with a field sensor band running parallel to the axis of the multi-conductor system relative to its surface normal.
  • FIG. 1 shows a measuring device 1 and a multi-conductor cable 14 in cross-section.
  • the multi-conductor cable 14 comprises three current ⁇ conductor 7. These current conductors 7 are arranged symmetrically about an imaginary center of the multi-conductor cable 14 in this embodiment. However, it is also conceivable that the power conductors 7 are not arranged symmetrically in the multi-conductor cable 14.
  • the measuring apparatus 1 to the Mes ⁇ sen the current strength is arranged reasonable in at least one current conductor.
  • the measuring device 1 comprises a flexible circuit ⁇ plate 2. It is also possible (not shown in figure), that two belts are arranged on each of the first and second radii on the flexible circuit board 2, which comprise the field ⁇ sensors.
  • a first field sensor 3 in a first radius R 1 and a second field sensor 4 in a second radius R 2 are arranged around the center of the multi-conductor system 14.
  • the ERS ⁇ te radius Rl here describes a larger radius around the center of the multi-conductor system around than the second radius R2.
  • the flexible printed circuit board 2 is arranged with respect to its surface normal 17 parallel to the axial direction of the multi-conductor system 2.
  • the first radius R1 and the second radius R2 depend on the requirements of the insulation, the geometry of the conductor arrangement, the current intensity and the type of field sensors used.
  • the first radius Rl of the first field sensors 3 is in this example
  • the magnet-sensitive direction of the field sensors 3, 4 is arranged at the same angle a s to the current conductor 7 to be measured.
  • One of the two mutually associated field sensors 3,4 is located on the outer radius Rl with a first distance 5 to the conductor 7 and the other on an inner radius R2 with a two ⁇ th distance 6 to the conductor 7 of the multi-conductor system 14. Based on the field difference between the inner and the outer field sensor, that is, the first field sensor 3 and the second field sensor 4, the sensor pair, and the first distance 5 or the second distance 6, the current flow in the current conductor 7 can be determined.
  • the three current conductors 7 to be measured each have six field sensors on the first radius R 1 and six field sensors on the second radius R 2.
  • the two field sensors 3, 4 are fluxgate sensors in this example. It is alternatively possible to use Hall sensors.
  • a signal evaluation device 8 is electrically connected to the flexible printed circuit board 2.
  • the signal evaluation device 8 is from at least two signals from at least two field sensors 3, 4 with two different radii R 1, R 2, in particular from a field sensor pair 16, to determine a current intensity in a single conductor 7 of a multi-conductor system 14.
  • the flexible circuit board 2 is shorter than the circumference of the multi-conductor cable 14, so that a first opening 15 remains free to go multi-conductor cable ⁇ fourteenth
  • the geometry of the multi-conductor cable 14 is known, so that the distances of the current conductor 7 to the two field sensors 3,4 are known.
  • Skalianssfak ⁇ factors can be determined.
  • a scaling factor a defined current is sent through the current conductor 7, and then the magnetic field is measured by means of the first and second field sensors 3, 4. From this, scaling factors can be calculated, which in turn can be used when flowing through an unknown current through the current conductor 7.
  • Figure 2 shows a plan view of the multi-conductor cable 14 and the measuring device 1.
  • the flexible circuit board 2 is arranged with its surface normal 17 pa ⁇ rallel to the current-carrying current conductor 7 in the multi-conductor cable 14. Furthermore, the opening 15 can be seen, since the flexible printed circuit board 2 is shorter than the circumference of the multi ⁇ conductor cable 14. Furthermore, the signal evaluation device 8 is arranged on the flexible printed circuit board 2. The determination of the current strength is based on the law of Biot-Savart:
  • Bio-Savart's law states that a current conductor of infinitesimal length dl at location r ', which is traversed by a current I, has the magnetic field strength dH at a location r.
  • a number M of currents from a number of N sensor signals can then be determined by means of the least squares method.
  • ⁇ ⁇ 1 is the magnetic field strength measured by the first field sensor 3, in the form of ⁇ , at the position ( ⁇ ⁇ ⁇ ⁇ 1 ).
  • ⁇ ⁇ 2 is the magnetic field strength measured by the second field sensor 4, denoted by ⁇ 2 in the formulas, at the position ( ⁇ ⁇ 2 ⁇ ⁇ 2).
  • I # is the stream at the location (x # y # ), that is in the
  • a 2 Equation 5-2 Gle i chung 6-1. .
  • the angle 3 ⁇ is the angle between the magnetic field sensitive direction of the sensor ⁇ and the x-axis of the coordinate system 9 in FIG. 1.
  • the angle 3 ⁇ 2 is the angle between the magnetic field sensitive direction of the sensor ⁇ 2 and the X axis.
  • Axis The coordinate system 9 relates to equations 2 to 7.
  • FIG. 3 shows a multi-conductor system 14 with a measuring device 1, the first field sensors 3 on a first band 12 and the second field sensors 4 on a second band 13 with their surface normal 17 parallel to the axial Direction of the multi-conductor system 14 are arranged.
  • the first band 12 and the second band 13 are firmly connected to one another, so that the spatially fixed radial arrangement of the field sensors 3, 4 can be ensured around the current conductor 7 during the operating or measuring phase.
  • the flexible band system comprising the first and second band 12, 13 advantageously has at least one opening 15, so that the mechanical flexibility can be currency ⁇ rend ensures the mounting of the measurement apparatus.
  • Both the mounting of the first and second bands 12, 13 and the mounting of a flexible circuit board 2 allows easy retrofitting to existing facilities with the measuring device 1 without major modifications or it allows temporary measurements, especially in the commissioning ⁇ me a plant.

Abstract

Device and method for measuring the strength of the current of an individual conductor (7) of a multi-conductor system (14). Device (1) and method for measuring a strength of the current in a current conductor (7) of a multi-conductor system (14) having at least two current conductors (7) with at least two field sensors (3, 4), wherein each field sensor (3, 4) is suitable for measuring a magnetic field resulting from a linear combination of the magnetic fields of the individual current conductors (7) and converting them into an electrical signal. In this context, one field sensor (3) is arranged around the multi-conductor system (14) on a first radius (R1), and one field sensor (4) is arranged around the multi-conductor system (14) on a second radius (R2), wherein the first radius (R1) is larger than the second radius (R2). Furthermore, the device (1) comprises a signal evaluation device (8) which is suitable for determining the strength of the current in the current conductor (7) by means of the difference between the signals of the at least two field sensors (3, 4) and by means of at least a first distance (5) or a second distance (6) of the current conductor (7) from one of the field sensors (3, 4).

Description

Vorrichtung und Verfahren zur Messung der Stromstärke eines einzelnen Leiters eines Mehrleitersystems Apparatus and method for measuring the current strength of a single conductor of a multi-conductor system
Die Erfindung betrifft eine Vorrichtung und ein Verfahren zur Messung der Stromstärke eines einzelnen Leiters eines Mehr¬ leitersystems . The invention relates to a device and a method for measuring the current intensity of a single conductor of a multi ¬ conductor system.
Zur Übertragung von Wechselstrom, seltener auch von Gleichstrom, werden Mehrleiterkabel umfassend wenigstens zwei Lei- ter verwendet. Bei Mehrleiterkabeln wird jeder Leiter für sich der Spannung entsprechend isoliert. Alle Leiter werden dann typischerweise miteinander verseilt und nochmals mit ei¬ nem gemeinsamen Isolationsmaterial umkleidet. Das Messen des Stromflusses in einem einzelnen Leiter eines solchen Mehrleitersystems kann mittels Shuntwiderständen, Ringkernwandlern, Rogowskispulen oder mit einem auf einer Feldsonde basierenden Sensorsystem erfolgen. For the transmission of alternating current, more often also of direct current, multi-conductor cables comprising at least two conductors are used. With multi-conductor cables, each conductor is isolated according to the voltage. All conductors are then typically stranded together and again covered with egg ¬ nem common insulation material. The measurement of the current flow in a single conductor of such a multi-conductor system can be effected by means of shunt resistors, toroidal transformers, Rogowski coils or with a field-probe-based sensor system.
Nachteiligerweise muss allerdings der zu messende Leiter ein- zeln für eine Messung zugänglich sein, was häufig bedeutet, dass das Mehrleiterkabel aufgetrennt werden muss.  However, disadvantageously, the conductor to be measured must be accessible individually for a measurement, which often means that the multi-conductor cable has to be separated.
In der deutschen Patentanmeldung DE 102016210970.7 wird ein Mess-System vorgeschlagen, mit welchem der Stromfluss in ei- nem einzelnen nicht direkt zugänglichen Leiter eines Mehrleitersystems gemessen werden kann ohne das Mehrleitersystem zu beschädigen. Das Mess-System umfasst wenigstens zwei Feldsensoren, die auf einer Leiterplatte um das Mehrleitersystem herum angeordnet sind. Die Feldsensoren sind geeignet, ein Magnetfeld resultierend aus einer Linearkombination der Mag¬ netfelder der einzelnen Stromleiter zu messen und in ein elektrisches Signal umzuwandeln. Das Mess-System umfasst auch eine Signalauswertevorrichtung, mittels der die Stromstärke in dem Stromleiter mittels der Signale der wenigstens zwei Feldsensoren und mittels wenigstens eines Abstands des Strom¬ leiters zu einem der Feldsensoren ermittelt wird. In the German patent application DE 102016210970.7 a measuring system is proposed, with which the current flow in a single not directly accessible conductor of a multi-conductor system can be measured without damaging the multi-conductor system. The measuring system comprises at least two field sensors which are arranged on a printed circuit board around the multi-conductor system. The field sensors are suitable, a magnetic field resulting from a linear combination of the Mag ¬ netfelder of each conductor to be measured and convert them into an electrical signal. The measuring system also includes a signal evaluation device, by means of which the current in the current conductor is determined by means of the signals of the at least two field sensors and by at least a distance of the current ¬ conductor to one of the field sensors.
Nachteiligerweise ist dieses Mess-System empfindlich gegen- über Fremdfeldern, wodurch die Messung des Stromflusses im Leiter verfälscht werden kann. Disadvantageously, this measuring system is sensitive to via external fields, whereby the measurement of the current flow in the conductor can be falsified.
Es ist daher Aufgabe der vorliegenden Erfindung eine Vorrich- tung und ein Verfahren anzugeben, mit welchem der Stromfluss in einem nicht direkt zugänglichen Mehrleitersystem gemessen werden kann und das dabei unempfindlich gegenüber Fremdfeldern ist. Die Aufgabe wird mit einer Vorrichtung gemäß Anspruch 1 und einem Verfahren gemäß Anspruch 10 gelöst. It is therefore an object of the present invention to provide a device and a method with which the current flow in a not directly accessible multi-conductor system can be measured and which is insensitive to external fields. The object is achieved with a device according to claim 1 and a method according to claim 10.
Die erfindungsgemäße Vorrichtung zum Messen einer Stromstärke in einem Stromleiter eines Mehrleitersystems mit wenigstens zwei Stromleitern umfasst wenigstens zwei Feldsensoren. Jeder Feldsensor ist geeignet, ein Magnetfeld resultierend aus ei¬ ner Linearkombination der Magnetfelder der einzelnen Stromleiter zu messen und in ein elektrisches Signal umzuwandeln. Ein erster Feldsensor ist auf einem ersten Radius kreisseg- mentartig um den Stromleiter angeordnet und ein zweiter Feld¬ sensor ist auf einem zweiten Radius kreissegmentartig um den Stromleiter angeordnet, wobei der erste Radius größer als der zweite Radius ist. Die Vorrichtung umfasst weiterhin eine Signalauswertevorrichtung, welche geeignet ist, die Strom- stärke in dem Stromleiter mittels der Differenz der Signale der wenigstens zwei Feldsensoren und mittels wenigstens eines ersten Abstands des Stromleiters zu dem ersten Feldsensoren oder mittels eines zweiten Abstands des Stromleiters zu dem zweiten Feldsensor zu ermitteln. The device according to the invention for measuring a current intensity in a conductor of a multi-conductor system with at least two conductors comprises at least two field sensors. Each field sensor is suitable to measure a magnetic field resulting from egg ¬ ner linear combination of the magnetic fields of the individual conductors and convert it into an electrical signal. A first field sensor is arranged on a first radius kreisseg- element-like around the conductor and a second field ¬ sensor is arranged on a second radius in a circle segment around the conductor, wherein the first radius is greater than the second radius. The apparatus further comprises a signal evaluation device which is suitable for determining the current intensity in the current conductor by means of the difference of the signals of the at least two field sensors and by means of at least a first distance of the current conductor to the first field sensor or by means of a second distance of the current conductor to the second field sensor to investigate.
Durch die Zuordnung der Sensorsignale der zwei Feldsensoren in unterschiedlichem Abstand zu dem Stromleiter und durch Bilden der Differenz der Signale, wird der störende Einfluss von Fremdfeldern, insbesondere von homogenen Fremdmagnetfel¬ dern, auf das Ergebnis der Ermittlung der Stromstärke in dem Stromleiter deutlich reduziert. Das Auftrennen der Mehrleitersysteme derart, dass einzelne Stromleiter direkt zugäng- lieh sind, wird vorteilhaft vermieden. Weiterhin kann vorteilhaft eine Messbereichserweiterung erreicht werden. By assigning the sensor signals of the two field sensors at different distances from the conductor and by forming the difference of the signals, the disturbing influence of external fields, in particular homogeneous Fremdmagnetfel ¬ countries, significantly reduced to the result of determining the current in the conductor. The separation of the multi-conductor systems in such a way that individual conductors are directly accessible. lent, is advantageously avoided. Furthermore, advantageously, a measuring range extension can be achieved.
In einer vorteilhaften Ausgestaltung und Weiterbildung der Erfindung sind der erste und der zweite Feldsensor auf einer gemeinsamen Leiterplatte angeordnet. Alle Feldsensoren, das bedeutet sowohl die Feldsensoren auf dem ersten Radius als auch die Feldsensoren auf dem zweiten Radius, sind auf der gemeinsamen Leiterplatte angeordnet und können um das Mehr- leitersystem gelegt und fixiert werden. Somit sind die rela¬ tive Lage und der Abstand der Feldsensoren untereinander und zu dem zu messenden Stromleiter während der Messung konstant. Dies ermöglicht vorteilhaft konstante Messungen. In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung sind der erste Feldsensor auf einer ersten Leiterplatte und der zweite Feldsensor auf einer zweiten Lei¬ terplatte angeordnet. Vorteilhaft können so der erste und der zweite Radius unabhängig voneinander gewählt werden. In an advantageous embodiment and development of the invention, the first and the second field sensor are arranged on a common printed circuit board. All field sensors, ie both the field sensors on the first radius and the field sensors on the second radius, are arranged on the common printed circuit board and can be placed around the multi-conductor system and fixed. Thus, the rela ¬ tive position and the distance of the field sensors to each other and to the current conductor to be measured during the measurement are constant. This advantageously allows constant measurements. In a further advantageous embodiment and development of the invention, the first field sensor on a first circuit board and the second field sensor on a second Lei ¬ terplatte are arranged. Advantageously, the first and the second radius can be selected independently of each other.
In einer vorteilhaften Ausgestaltung und Weiterbildung der Erfindung ist die gemeinsame Leiterplatte, die erste und/oder die zweite Leiterplatte als flexible Leiterplatte ausgestal¬ tet. Vorteilhaft kann somit die Leiterplatte mit den Feldsen- soren variabel um das Mehrleitersystem gelegt werden. Das Mehrleitersystem kann dabei unterschiedliche Formen haben, insbesondere kreis- oder ovalförmig. Weiterhin müssen der Umfang des Mehrleitersystems und die Länge der ersten und/oder zweiten Leiterplatte nicht genau aufeinander abgestimmt sein. Es ist vorteilhaft ausreichend, wenn die Leiterplatten je¬ weils teilweise um das Mehrleitersystem herum gelegt werden können. Durch ein Fixieren der flexiblen Leiterplatte um das Mehrleitersystem herum, ist gewährleistet, dass der Abstand der Feldsensoren zu dem jeweiligen einzelnen Stromleiter, der zu messen ist, konstant gehalten wird. Vorteilhaft kann die flexible Leiterplatte sowohl an neuen Mehrleitersystemen, wie auch an bereits verbauten Altanlagen eingebaut werden. Die Fixierung kann beispielsweise durch flexible Klemmen, eine Verschraubung oder durch einen auf Passung gefertigten Adapter erfolgen. In an advantageous embodiment and development of the invention, the common circuit board, the first and / or the second circuit board as a flexible circuit board ausgestal ¬ Tet. Advantageously, the printed circuit board with the field sensors can thus be laid variably around the multi-conductor system. The multi-conductor system can have different shapes, in particular circular or oval-shaped. Furthermore, the scope of the multi-conductor system and the length of the first and / or second circuit board need not be exactly matched. It is advantageous sufficient if the printed circuit boards each ¬ weils partially can be placed around the multi-conductor system around. By fixing the flexible circuit board around the multi-conductor system, it is ensured that the distance of the field sensors to the respective individual conductor to be measured is kept constant. Advantageously, the flexible circuit board can be installed both on new multi-conductor systems, as well as already installed old systems. The fixation, for example, by flexible terminals, a Screwed or made by an adapter made to fit.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbil- dung der Erfindung ist die Anzahl der Feldsensoren auf einer Leiterplatte gleich oder größer als die Anzahl der Stromlei¬ ter. Vorteilhaft ist es dann möglich, für jeden einzelnen Stromleiter des Mehrleitersystems die Stromstärke zu bestim¬ men. Die Feldsensoren weisen unterschiedliche Abstände zum zu messenden Stromleiter auf. Da das Magnetfeld eines geraden stromdurchflossenen Stromleiters reziprok mit dem Abstand abnimmt, kann dann mit Hilfe einer Linearkombinationen der Magnetfelder der einzelnen Stromleiter auf die Stromstärke in einem bestimmten einzelnen Stromleiter zurückgeschlossen wer- den. In a further advantageous embodiment and further development of the invention, the number of field sensors on a printed circuit board is equal to or greater than the number of Stromlei ¬ ter. It is advantageous possible for each individual conductors of multi-conductor system, the current strength during limited ¬ men. The field sensors have different distances to the current conductor to be measured. Since the magnetic field of a straight current-carrying conductor decreases reciprocally with the distance, it is then possible with the aid of a linear combination of the magnetic fields of the individual conductors to deduce the current intensity in a specific individual current conductor.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung ist die Anzahl der Feldsensoren auf der ersten und zweiten Leiterplatte gleich. Vorteilhafterweise sind dann jeweils ein erster und ein zweiter Feldsensor einander paarweise zugeordnet. Die beiden Sensoren können dann vorteilhaft Signale erzeugen, welche zur Ermittlung des In a further advantageous embodiment and development of the invention, the number of field sensors on the first and second circuit board is the same. Advantageously, a first and a second field sensor are then assigned to each other in pairs. The two sensors can then advantageously produce signals which are used to determine the
Stromflusses in dem zu messenden Stromleiter herangezogen werden. Die Differenz dieser beiden Signale ermöglicht vor- teilhaft, den Einfluss von Fremdfeldern, insbesondere von ho¬ mogenen Fremdmagnetfeldern, zu minimieren. Current flow are used in the current conductor to be measured. The difference between these two signals allows forward part way to minimize the influence of external fields, in particular ho ¬ geneous external magnetic fields.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung liegt das Verhältnis des ersten Radius zu dem zweiten Radius in einem Bereich zwischen 1,1 und 3. In diesem Bereich sind die Messsignale des ersten und zweiten Feldsensor einerseits ausreichend unterschiedlich, um Fremdfelder von der Messung ausschließen zu können, und andererseits noch in derselben Größenordnung, um die Stromstärke be- rechnen zu können. In a further advantageous embodiment and development of the invention, the ratio of the first radius to the second radius is in a range between 1.1 and 3. On the one hand, the measuring signals of the first and second field sensors are sufficiently different in this area to exclude foreign fields from the measurement and on the other hand of the same order of magnitude in order to be able to calculate the current intensity.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung sind der erste Feldsensor und der zweite Feldsensor radial fluchtend, das heißt von einem Mittelpunkt des Mehrleitersystems aus auf einer Linie, angeordnet. Die empfindliche Richtung der Feldsensoren ist dabei im Wesentli¬ chen parallel zueinander ausgerichtet. Vorteilhaft kann durch diese Anordnung der Feldsensoren der Einfluss von homogenen Fremdfeldern auf die Ermittlung des Stromflusses in dem In a further advantageous embodiment and development of the invention, the first field sensor and the second Field sensor radially aligned, that is arranged from a center of the multi-conductor system on a line. The sensitive direction of the field sensors is aligned parallel to one another Wesentli ¬ chen. Advantageously, by this arrangement of the field sensors, the influence of homogeneous external fields on the determination of the current flow in the
Stromleiter weiter minimiert werden. Current conductors are further minimized.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbil- dung der Erfindung ist wenigstens einer der Feldsensoren ein Fluxgate-Sensor oder ein Hall-Sensor. Unter einem Fluxgate- Sensor wird ein Sensor verstanden, welche ein Magnetometer zur vektoriellen Bestimmung eines Magnetfelds darstellt. Der Fluxgate-Sensor wird auch Förstersonde genannt. Mit Fluxgate- Sensoren ist es möglich, Magnetfelder von 0, 1 nT bis 5 mT zu messen. Ein Hall-Sensor nutzt vorteilhaft den Halleffekt zur Messung von Magnetfeldern. Vorteilhaft verändert ein Hall- Sensor das zu messende Magnetfeld nicht, da keine magnetisch aktiven Materialien in Hall-Sensoren verbaut werden müssen. In a further advantageous embodiment and further development of the invention, at least one of the field sensors is a fluxgate sensor or a Hall sensor. A fluxgate sensor is understood to mean a sensor which represents a magnetometer for the vectorial determination of a magnetic field. The fluxgate sensor is also called a forester probe. With fluxgate sensors it is possible to measure magnetic fields from 0, 1 nT to 5 mT. A Hall sensor advantageously uses the Hall effect to measure magnetic fields. Advantageously, a Hall sensor does not change the magnetic field to be measured, since no magnetically active materials have to be installed in Hall sensors.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung sind der erste und der zweite Feldsensor im Wesentlichen planar zueinander angeordnet. Die erste und die zweite Leiterplatte sind dann auch im Wesentlichen zuei¬ nander planar angeordnet. Die empfindliche Richtung der je¬ weiligen Feldsensoren ist dabei parallel zueinander ausgerichtet . In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung sind die Leiterplatten derart um das Mehrleitersystem angeordnet, dass die Leiterplatten bezüglich ihrer Flächennormalen parallel zur axialen Richtung des Mehrleiterkabels angeordnet ist. Bei dieser Anordnung ist der Ab- stand des ersten und zweiten Feldsensors zueinander und zum Mittelpunkt des Mehrleitersystems in radialer Richtung kon¬ stant. Weiterhin kann der Abstand der Feldsensoren zum Mittelpunkt des Systems leicht über den Umfang ermittelt werden, sodass dieser Abstand bekannt ist. Diese Anordnung kann damit vorteilhaft die notwendige Flexibilität während der Montage¬ phase der Leiterplatte gewährleisten und weiterhin vorteil¬ haft die räumlich feste radiale Anordnung der Feldsensoren zueinander und zu den zu messenden Stromleitern während der Mess-Phase gewährleisten. In a further advantageous embodiment and development of the invention, the first and the second field sensor are arranged substantially planar to one another. The first and the second circuit board are then also arranged substantially zuei ¬ nander planar. The sensitive direction of each ¬ weiligen field sensors is aligned parallel to one another. In a further advantageous embodiment and development of the invention, the printed circuit boards are arranged around the multi-conductor system such that the printed circuit boards are arranged with respect to their surface normal parallel to the axial direction of the multi-conductor cable. In this arrangement, the distance-of the first and second field sensor to each other and to the center of the multi-conductor system in the radial direction kon ¬ constant. Furthermore, the distance of the field sensors to the center of the system can be easily determined over the circumference, so that this distance is known. This arrangement can thus advantageously ensure the necessary flexibility during the assembly ¬ phase of the circuit board and continue to ¬ advantageous to ensure the spatially fixed radial arrangement of the field sensors to each other and to be measured conductors during the measurement phase.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung ist die Länge der Leiterplatte derart wählbar, dass das Mehrleitersystem kreissegmentartig wenigs¬ tens 180° um das Mehrleitersystem herum angeordnet ist. Vorteilhafterweise kann die Leiterplatte unterschiedliche Mehr¬ leitersysteme mit unterschiedlichen Umfangslängen und Um- fangsformen herum angeordnet werden. In a further advantageous refinement and further development of the invention, the length of the circuit board is selectable such that the multi-wire system is arranged in a circular segment-like Wenig ¬ least 180 ° around the multi-conductor system around. Advantageously, the circuit board can be arranged different multi ¬ conductor systems with different circumferential lengths and circumferences around.
In einer weiteren vorteilhaften Ausgestaltung und Weiterbildung der Erfindung ist die Signalauswertevorrichtung auf der Leiterplatte angeordnet. Vorteilhaft ist zum Messen der In a further advantageous embodiment and development of the invention, the signal evaluation device is arranged on the circuit board. It is advantageous for measuring the
Stromstärke in einem Stromleiter dann lediglich das Anbringen der gesamten Vorrichtung nötig und das zusätzliche Anbringen von Signalauswertevorrichtungen kann vorteilhaft vermieden werden . Amperage in a conductor then only necessary to attach the entire device and the additional attachment of Signalauswertevorrichtungen can be advantageously avoided.
Bei dem erfindungsgemäßen Verfahren wird eine Stromstärke ei- nes Stromleiters in einem Mehrleitersystem mittels des Aus¬ wertens wenigstens zweier elektrischer Signale aus wenigstens zwei Feldsensoren in einer Signalauswertevorrichtung bestimmt. Aus einem ersten Signal wird eine erste magnetische Feldstärke ermittelt und aus einem zweiten Signal wird eine zweite magnetische Feldstärke ermittelt. Weiterhin ist ein erster Abstand zwischen dem ersten Feldsensor und dem Stromleiter bekannt oder es ist ein zweiter Abstand zwischen dem zweiten Feldsensor und dem Stromleiter bekannt. Unter Verwendung des Gesetzes von Biot-Savart wird dann aus der Differenz der ersten und zweiten magnetischen Feldstärke und aus dem ersten oder dem zweiten Abstand die Stromstärke des Stromlei¬ ters ermittelt. Weitere Ausgestaltungsformen und weitere Merkmale der Erfindung werden anhand der folgenden Figuren näher erläutert. Dabei zeigen: Figur 1 einen Querschnitt einer Messvorrichtung mit Mehrleitersystem; In the inventive method a current egg nes current conductor in a multi-conductor system by means of the off ¬ valuing at least two electrical signals from at least two field sensors is determined in a signal evaluation device. From a first signal, a first magnetic field strength is determined and from a second signal, a second magnetic field strength is determined. Furthermore, a first distance between the first field sensor and the current conductor is known, or a second distance between the second field sensor and the current conductor is known. By using the law of Biot-Savart the amperage of the Stromlei ¬ ters is then determined from the difference of the first and second magnetic field strength and from the first or the second distance. Further embodiments and further features of the invention will be explained in more detail with reference to the following figures. 1 shows a cross-section of a measuring device with a multi-conductor system;
Figur 2 eine Draufsicht einer Messvorrichtung mit Mehrleitersystem; Figure 2 is a plan view of a multi-conductor system measuring apparatus;
Figur 3 ein Mehrleitersystem mit einem zu seiner Flächennormalen parallel zur Achse des Mehrleitersystems laufendem Feldsensorband . Figur 1 zeigt eine Messvorrichtung 1 und ein Mehrleiterkabel 14 im Querschnitt. Das Mehrleiterkabel 14 umfasst drei Strom¬ leiter 7. Diese Stromleiter 7 sind in diesem Ausführungsbeispiel symmetrisch um eine gedachte Mitte des Mehrleiterkabels 14 angeordnet. Es ist aber ebenso denkbar, dass die Stromlei- ter 7 nicht symmetrisch in dem Mehrleiterkabel 14 angeordnet sind . FIG. 3 shows a multi-conductor system with a field sensor band running parallel to the axis of the multi-conductor system relative to its surface normal. FIG. 1 shows a measuring device 1 and a multi-conductor cable 14 in cross-section. The multi-conductor cable 14 comprises three current ¬ conductor 7. These current conductors 7 are arranged symmetrically about an imaginary center of the multi-conductor cable 14 in this embodiment. However, it is also conceivable that the power conductors 7 are not arranged symmetrically in the multi-conductor cable 14.
Um das Mehrleiterkabel 14 ist die Messvorrichtung 1 zum Mes¬ sen der Stromstärke in wenigstens einem Stromleiter 7 ange- ordnet. Die Messvorrichtung 1 umfasst eine flexible Leiter¬ platte 2. Es ist auch möglich (nicht in Figur gezeigt), dass auf der flexiblen Leiterplatte 2, zwei Bänder auf jeweils dem ersten und zweiten Radius angeordnet sind, welche die Feld¬ sensoren umfassen. Auf der flexiblen Leiterplatte 2 in diesem Beispiel sind ein erster Feldsensor 3 in einem ersten Radius Rl und ein zweiter Feldsensor 4 in einem zweiten Radius R2 um die Mitte des Mehrleitersystems 14 herum angeordnet. Der ers¬ te Radius Rl beschreibt dabei einen größeren Radius um die Mitte des Mehrleitersystems herum als der zweite Radius R2. To the multi-conductor cable 14, the measuring apparatus 1 to the Mes ¬ sen the current strength is arranged reasonable in at least one current conductor. 7 The measuring device 1 comprises a flexible circuit ¬ plate 2. It is also possible (not shown in figure), that two belts are arranged on each of the first and second radii on the flexible circuit board 2, which comprise the field ¬ sensors. On the flexible printed circuit board 2 in this example, a first field sensor 3 in a first radius R 1 and a second field sensor 4 in a second radius R 2 are arranged around the center of the multi-conductor system 14. The ERS ¬ te radius Rl here describes a larger radius around the center of the multi-conductor system around than the second radius R2.
Auf jedem dieser beiden Radien Rl, R2 um die Mitte des Mehrleiterkabels 14 befinden sich wenigstens so viele Feldsenso¬ ren 3, 4 wie Stromleiter 7 in dem Mehrleitersystem 14 vorhan- den sind. Von der Mitte des Mehrleiterkabels 14 aus gesehen sind der erste und der zweite Feldsensor 3, 4 auf einer Linie 10 fluchtend angeordnet. Das bedeutet auch, dass die empfind¬ liche Richtung 11 der beiden Feldsensoren 3, 4 parallel zuei- nander angeordnet ist. Ein Sensorpaar 16 zeigt Figur 1. Die empfindliche Richtung 11 der ersten Feldsensoren 3 und der zweiten Feldsensoren 4 ist parallel zum Umfang der flexiblen Leiterplatte 2 angeordnet. Die flexible Leiterplatte 2 ist bezüglich ihrer Flächennormalen 17 parallel zur axialen Rich- tung des Mehrleitersystems 2 angeordnet. Der erste Radius Rl und der zweite Radius R2 hängen von den Anforderungen an die Isolation, die Geometrie der Leiteranordnung, der Stromstärke und der Art der verwendeten Feldsensoren ab. Der erste Radius Rl der ersten Feldsensoren 3 beträgt in diesem Beispiel On each of these two radii Rl, R2 to the center of the multi-conductor cable 14 are at least as many Feldsenso ¬ ren 3, 4 as current conductor 7 in the multi-conductor system 14 existing they are. As seen from the center of the multi-conductor cable 14, the first and second field sensors 3, 4 are aligned on a line 10. This also means that the SENS ¬ Liche direction of the two field sensors 3, 4 arranged in parallel zuei- Nander. 11 A sensor pair 16 is shown in FIG. 1. The sensitive direction 11 of the first field sensors 3 and of the second field sensors 4 is arranged parallel to the circumference of the flexible printed circuit board 2. The flexible printed circuit board 2 is arranged with respect to its surface normal 17 parallel to the axial direction of the multi-conductor system 2. The first radius R1 and the second radius R2 depend on the requirements of the insulation, the geometry of the conductor arrangement, the current intensity and the type of field sensors used. The first radius Rl of the first field sensors 3 is in this example
Rl=70mm und der zweite Radius R2= 54mm. Dadurch, dass die empfindliche Richtung 11 der Feldsensoren parallel angeordnet ist, ist die magnetempfindliche Richtung der Feldsensoren 3, 4 unter dem gleichen Winkel as zu dem zu messenden Stromleiter 7 angeordnet. Einer der beiden paarweise einander zu- geordneten Feldsensoren 3,4 befindet sich dabei auf dem äußeren Radius Rl mit einem ersten Abstand 5 zum dem Stromleiter 7 und der andere auf einem inneren Radius R2 mit einem zwei¬ ten Abstand 6 zu dem Stromleiter 7 des Mehrleitersystems 14. Basierend auf der Felddifferenz zwischen dem inneren und dem äußeren Feldsensor, also dem ersten Feldsensor 3 und dem zweiten Feldsensor 4, des Sensorpaares, und dem ersten Abstand 5 oder dem zweiten Abstand 6 kann der Stromfluss in dem Stromleiter 7 ermittelt werden. In diesem Beispiel sind den drei zu messenden Stromleitern 7 jeweils sechs Feldsensoren auf dem ersten Radius Rl und sechs Feldsensoren auf dem zweiten Radius R2 angeordnet. Die beiden Feldsensoren 3,4 sind in diesem Beispiel Fluxgate-Sensoren . Es ist alternativ möglich, Hallsensoren einzusetzen. Rl = 70mm and the second radius R2 = 54mm. Because the sensitive direction 11 of the field sensors is arranged in parallel, the magnet-sensitive direction of the field sensors 3, 4 is arranged at the same angle a s to the current conductor 7 to be measured. One of the two mutually associated field sensors 3,4 is located on the outer radius Rl with a first distance 5 to the conductor 7 and the other on an inner radius R2 with a two ¬ th distance 6 to the conductor 7 of the multi-conductor system 14. Based on the field difference between the inner and the outer field sensor, that is, the first field sensor 3 and the second field sensor 4, the sensor pair, and the first distance 5 or the second distance 6, the current flow in the current conductor 7 can be determined. In this example, the three current conductors 7 to be measured each have six field sensors on the first radius R 1 and six field sensors on the second radius R 2. The two field sensors 3, 4 are fluxgate sensors in this example. It is alternatively possible to use Hall sensors.
Zum Auswerten der Signale der Feldsensoren 3,4 ist eine Signalauswertevorrichtung 8 elektrisch mit der flexiblen Leiterplatte 2 verbunden. Die Signalauswertevorrichtung 8 ist ge- eignet, aus wenigstens zwei Signalen von wenigstens zwei Feldsensoren 3, 4 mit zwei unterschiedlichen Radien Rl, R2, insbesondere aus einem Feldsensorpaar 16, eine Stromstärke in einem einzelnen Leiter 7 eines Mehrleitersystems 14 zu ermit- teln. Durch die Verwendung von zwei konzentrisch ringförmig um den Stromleiter 7 angeordneten Feldsensoren 3,4 und der parallele Ausrichtung bezüglich der empfindlichen Richtung 11, kann unter Verwendung magnetischer Felddifferenzen der störende Einfluss von Fremdfeldern auf das Ergebnis deutlich verringert werden. For evaluating the signals of the field sensors 3, 4, a signal evaluation device 8 is electrically connected to the flexible printed circuit board 2. The signal evaluation device 8 is from at least two signals from at least two field sensors 3, 4 with two different radii R 1, R 2, in particular from a field sensor pair 16, to determine a current intensity in a single conductor 7 of a multi-conductor system 14. By using two field sensors 3,4 arranged concentrically in a ring around the current conductor 7 and the parallel orientation with respect to the sensitive direction 11, the disturbing influence of extraneous fields on the result can be significantly reduced by using magnetic field differences.
Die flexible Leiterplatte 2 ist kürzer als der Umfang des Mehrleiterkabels 14, sodass eine erste Öffnung 15 zum Mehr¬ leiterkabel 14 hin frei bleibt. The flexible circuit board 2 is shorter than the circumference of the multi-conductor cable 14, so that a first opening 15 remains free to go multi-conductor cable ¬ fourteenth
Zum Ermitteln der Stromstärke in dem Stromleiter 7, muss wenigstens der erste 5 oder der zweite Abstand 6 bekannt sein. In diesem Beispiel ist die Geometrie des Mehrleiterkabels 14 bekannt, sodass die Abstände des Stromleiters 7 zu den beiden Feldsensoren 3,4 bekannt sind. Im Falle, dass die Geometrie des Mehrleiterkabels 14 unbekannt ist, können Skalierungsfak¬ toren ermittelt werden. Zum Ermitteln eines Skalierungsfaktors wird eine definierte Stromstärke durch den Stromleiter 7 geschickt, und anschließend wird mittels des ersten und zwei- ten Feldsensors 3,4 das Magnetfeld gemessen. Daraus lassen sich Skalierungsfaktoren berechnen, welche wiederum beim Durchströmen einer unbekannten Stromstärke durch den Stromleiter 7 herangezogen werden können. Figur 2 zeigt eine Draufsicht des Mehrleiterkabels 14 und der Messvorrichtung 1. In dieser Ansicht ist gut zu sehen, dass die flexible Leiterplatte 2 mit ihrer Flächennormalen 17 pa¬ rallel zum stromführenden Stromleiter 7 im Mehrleiterkabel 14 angeordnet ist. Weiterhin ist die Öffnung 15 zu sehen, da die flexible Leiterplatte 2 kürzer ist als der Umfang des Mehr¬ leiterkabels 14. Weiterhin ist die Signalauswertevorrichtung 8 auf der flexiblen Leiterplatte 2 angeordnet. Das Ermitteln der Stromstärke erfolgt basierend auf dem Gesetz von Biot-Savart: For determining the current intensity in the current conductor 7, at least the first 5 or the second distance 6 must be known. In this example, the geometry of the multi-conductor cable 14 is known, so that the distances of the current conductor 7 to the two field sensors 3,4 are known. In the event that the geometry of the multi-conductor cable 14 is unknown, Skalierungsfak ¬ factors can be determined. To determine a scaling factor, a defined current is sent through the current conductor 7, and then the magnetic field is measured by means of the first and second field sensors 3, 4. From this, scaling factors can be calculated, which in turn can be used when flowing through an unknown current through the current conductor 7. Figure 2 shows a plan view of the multi-conductor cable 14 and the measuring device 1. In this view is good to see that the flexible circuit board 2 is arranged with its surface normal 17 pa ¬ rallel to the current-carrying current conductor 7 in the multi-conductor cable 14. Furthermore, the opening 15 can be seen, since the flexible printed circuit board 2 is shorter than the circumference of the multi ¬ conductor cable 14. Furthermore, the signal evaluation device 8 is arranged on the flexible printed circuit board 2. The determination of the current strength is based on the law of Biot-Savart:
Gleichung 1Equation 1
Das Gesetz von Bio-Savart sagt aus, das ein Stromleiter der infinitesimalen Länge dl am Ort r', der von einem Strom I durchflössen wird an einem Ort r die magnetische Feldstärke dH aufweist. Bio-Savart's law states that a current conductor of infinitesimal length dl at location r ', which is traversed by a current I, has the magnetic field strength dH at a location r.
Nach Gleichung 2 bis 7 können dann eine Anzahl M Ströme aus einer Anzahl von N Sensorsignalen mittels der Methode der kleinsten Quadrate ermittelt werden. Dabei ist Ημ1 die magnetische Feldstärke, die vom ersten Feldsensor 3, in den For- mein μΐ, an der Stelle (χμιΥμ1) gemessen wird. Ημ2 ist die magnetische Feldstärke, die vom zweiten Feldsensor 4, in den Formeln mit μ2 bezeichnet, an der Stelle (χ μ2Υμ2) gemessen wird. I# ist der Strom an der Stelle (x#y#) , also in dem According to Equations 2 to 7, a number M of currents from a number of N sensor signals can then be determined by means of the least squares method. In this case, Η μ1 is the magnetic field strength measured by the first field sensor 3, in the form of μΐ, at the position (χ μ ιΥ μ1 ). Η μ2 is the magnetic field strength measured by the second field sensor 4, denoted by μ2 in the formulas, at the position ( χ μ 2Υ μ 2). I # is the stream at the location (x # y # ), that is in the
Stromleiter 7. Current conductor 7.
Ημ = Ημ · Gleichung 2 Η μ = Η μ · Equation 2
Ημι = Σ#=ι 3μΐθ · Gleichung 3-1 Η μ ι = Σ # = ι 3 μΐθ · Equation 3-1
Ημ2 = Σ#=ι 3μ2θ ' Gleichung 3-2 Η μ2 = Σ # = ι 3 μ2θ 'Equation 3-2
Η = Α1·Ϊ Gleichung 4-1 Η2 =Α2·Ι Gleichung 4-2 Η = Α 1 · Ϊ Equation 4-1 Η 2 = Α 2 · Ι Equation 4-2
Gleichung 5-1 Equation 5-1
A2 = Gleichung 5-2 Gleichung 6-1 . , A 2 = Equation 5-2 Gle i chung 6-1. .
Gleichung 6-2 Gle i chung 6-2
Gleichung 7 Equation 7
Der Winkel 3μι ist der Winkel zischen der magnetischen Feld empfindlichen Richtung des Sensors μΐ und der x-Achse des Ko- ordinatensystems 9 in Figur 1. Der Winkel 3μ2 ist der Winkel zischen der magnetischen Feld empfindlichen Richtung des Sensors μ2 und der X-Achse Das Koordinatensystem 9 bezieht sich auf Gleichungen 2 bis 7. Figur 3 zeigt ein Mehrleitersystem 14 mit einer Messvorrichtung 1, wobei die ersten Feldsensoren 3 auf einem ersten Band 12 und die zweiten Feldsensoren 4 auf einem zweiten Band 13 mit ihrer Flächennormalen 17 parallel zur axialen Richtung des Mehrleitersystems 14 angeordnet sind. Das erste Band 12 und das zweite Band 13 sind fest miteinander verbunden, so dass die räumlich feste radiale Anordnung der Feldsensoren 3, 4 um den Stromleiter 7 während der Betriebs- bzw. Messphase gewährleistet werden kann. Das flexible Bandsystem, umfassend das erste und zweite Band 12, 13 hat vorteilhaft wenigstens die eine Öffnung 15, damit die mechanische Flexibilität wäh¬ rend der Montage der Messvorrichtung 1 gewährleistet werden kann . The angle 3μ is the angle between the magnetic field sensitive direction of the sensor μ and the x-axis of the coordinate system 9 in FIG. 1. The angle 3μ 2 is the angle between the magnetic field sensitive direction of the sensor μ 2 and the X axis. Axis The coordinate system 9 relates to equations 2 to 7. FIG. 3 shows a multi-conductor system 14 with a measuring device 1, the first field sensors 3 on a first band 12 and the second field sensors 4 on a second band 13 with their surface normal 17 parallel to the axial Direction of the multi-conductor system 14 are arranged. The first band 12 and the second band 13 are firmly connected to one another, so that the spatially fixed radial arrangement of the field sensors 3, 4 can be ensured around the current conductor 7 during the operating or measuring phase. The flexible band system comprising the first and second band 12, 13 advantageously has at least one opening 15, so that the mechanical flexibility can be currency ¬ rend ensures the mounting of the measurement apparatus. 1
Sowohl das Montieren des ersten und zweiten Bands 12, 13 als auch das Montieren der einen flexiblen Leiterplatte 2 ermöglicht ein einfaches Nachrüsten an bestehenden Anlagen mit der Messvorrichtung 1 ohne größere Modifikationen oder es ermöglicht temporäre Messungen, insbesondere bei der Inbetriebnah¬ me einer Anlage. Both the mounting of the first and second bands 12, 13 and the mounting of a flexible circuit board 2 allows easy retrofitting to existing facilities with the measuring device 1 without major modifications or it allows temporary measurements, especially in the commissioning ¬ me a plant.

Claims

Patentansprüche claims
1. Vorrichtung (1) zum Messen einer Stromstärke in einem Stromleiter (7) eines Mehrleitersystems (14) mit wenigstens zwei Stromleitern (7) umfassend: 1. Device (1) for measuring a current intensity in a current conductor (7) of a multi-conductor system (14) with at least two current conductors (7) comprising:
- wenigstens zwei Feldsensoren (3, 4), wobei jeder Feldsensor (3, 4) geeignet ist, ein Magnetfeld resultierend aus einer Linearkombination der Magnetfelder der einzelnen Stromleiter (7) zu messen und in ein elektrisches Signal umzuwandeln, - wobei ein erster Feldsensor (3) auf einem ersten Radius - At least two field sensors (3, 4), each field sensor (3, 4) is adapted to measure a magnetic field resulting from a linear combination of the magnetic fields of the individual conductors (7) and convert it into an electrical signal, - wherein a first field sensor ( 3) on a first radius
(Rl) kreissegmentartig um den Stromleiter (7) angeordnet ist und ein zweiter Feldsensor (4) auf einem zweiten Radius (R2) kreissegmentartig um den Stromleiter (7) angeordnet ist, und der erste Radius (Rl) größer als der zweite Radius (R2) ist, - eine Signalauswertevorrichtung (8), welche geeignet ist, die Stromstärke in dem Stromleiter (7) mittels der Differenz der Signale der wenigstens zwei Feldsensoren (3, 4) und mit¬ tels wenigstens eines ersten Abstands (5) des ersten Feldsen¬ sors (3) zu dem Stromleiter (7) oder eines zweiten Abstands (6) des Stromleiters (7) zu dem zweiten Feldsensor (4) zu ermitteln . (Rl) is arranged like a circle segment around the current conductor (7) and a second field sensor (4) is arranged on a second radius (R2) like a circle around the current conductor (7), and the first radius (Rl) is greater than the second radius (R2 ), - a signal evaluation device (8), which is suitable, the current intensity in the current conductor (7) by means of the difference of the signals of the at least two field sensors (3, 4) and with ¬ means at least a first distance (5) of the first field ¬ sors (3) to the current conductor (7) or a second distance (6) of the current conductor (7) to the second field sensor (4) to determine.
2. Vorrichtung (1) nach Anspruch 1, wobei der erste und der zweite Feldsensor (3, 4) auf einer gemeinsamen Leiterplatte (2) angeordnet sind. 2. Device (1) according to claim 1, wherein the first and the second field sensor (3, 4) on a common printed circuit board (2) are arranged.
3. Vorrichtung (1) nach Anspruch 1, wobei der erste Feldsensor (3) auf einer ersten Leiterplatte und der zweite Feldsen¬ sor (4) auf einer zweiten Leiterplatte angeordnet ist. 3. Device (1) according to claim 1, wherein the first field sensor (3) on a first circuit board and the second Feldsen ¬ sensor (4) is arranged on a second circuit board.
4. Vorrichtung (1) nach Anspruch 2 oder 3, wobei die Leiterplatte als flexible Leiterplatte ausgestaltet ist. 4. Device (1) according to claim 2 or 3, wherein the circuit board is designed as a flexible printed circuit board.
5. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei die Anzahl der Feldsensoren (3, 4) auf dem ersten Radius (Rl) und auf dem zweiten Radius (R2) jeweils gleich oder größer als die Anzahl der Stromleiter (7) ist. 5. Device (1) according to one of the preceding claims, wherein the number of field sensors (3, 4) on the first radius (Rl) and on the second radius (R2) is equal to or greater than the number of current conductors (7) ,
6. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei die Anzahl der Feldsensoren (3, 4) auf dem ersten und zweiten Radius (Rl, R2) gleich ist. 6. Device (1) according to one of the preceding claims, wherein the number of field sensors (3, 4) on the first and second radius (Rl, R2) is the same.
7. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei die empfindliche Richtung (11) des ersten und zweiten Feldsensors (3, 4) parallel zueinander ausgerichtet ist. 7. Device (1) according to one of the preceding claims, wherein the sensitive direction (11) of the first and second field sensor (3, 4) is aligned parallel to each other.
8. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei das Verhältnis des ersten Radius (Rl) zu dem zweiten8. Device (1) according to one of the preceding claims, wherein the ratio of the first radius (Rl) to the second
Radius (R2) in einem Bereich zwischen 1,1 und 3 liegt. Radius (R2) is in a range between 1.1 and 3.
9. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei der erste Feldsensor (3) und der zweite Feldsensor (4) radial fluchtend (10) zueinander angeordnet sind. 9. Device (1) according to one of the preceding claims, wherein the first field sensor (3) and the second field sensor (4) are arranged radially aligned (10) to each other.
10. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei der erste (3) und der zweite Feldsensor (4) im Wesent¬ lichen planar zueinander angeordnet sind. 10. Device (1) according to any one of the preceding claims, wherein the first (3) and the second field sensor (4) in the union Wesent ¬ planar to each other are arranged.
11. Vorrichtung (1) nach einem der vorhergehenden Ansprüche, wobei wenigstens einer der Feldsensoren (3, 4) ein Fluxgate- Sensor oder ein Hall-Sensor11. Device (1) according to one of the preceding claims, wherein at least one of the field sensors (3, 4) is a fluxgate sensor or a Hall sensor
12. Vorrichtung (1) nach einem der Ansprüche 2 bis 11, wobei die Leiterplatte (2) derart um das Mehrleitersystem (2) ange¬ ordnet ist, dass die Leiterplatte (2) bezüglich ihrer Flä¬ chennormalen (16) parallel zur axialen Richtung des Mehrleitersystems (2) angeordnet ist. 12. Device (1) according to any one of claims 2 to 11, wherein the circuit board (2) in such a way to the multi-conductor system (2) is integrally ¬ arranged that the printed circuit board (2) with respect to their FLAE ¬ normals (16) parallel to the axial direction of the multi-conductor system (2) is arranged.
13. Vorrichtung (1) nach einem der Ansprüche 2 bis 12, wobei eine Länge der Leiterplatte (2) derart wählbar ist, dass das Mehrleitersystem (14) kreissegmentartig wenigstens 180° um das Mehrleitersystem (14) herum angeordnet ist. 13. Device (1) according to one of claims 2 to 12, wherein a length of the printed circuit board (2) is selectable such that the multi-conductor system (14) is arranged in a circle segment at least 180 ° around the multi-conductor system (14) around.
14. Vorrichtung (1) gemäß einem der Ansprüche 2 bis 13, wobei die Signalauswertevorrichtung (8) auf der Leiterplatte (2) angeordnet ist. 14. Device (1) according to one of claims 2 to 13, wherein the signal evaluation device (8) on the printed circuit board (2) is arranged.
15. Verfahren zum Auswerten wenigstens zweier elektrischer Signale aus wenigstens zwei Feldsensoren (3, 4) in einer Sig¬ nalauswertevorrichtung (8) zum Bestimmen einer Stromstärke eines Stromleiters (7) in einem Mehrleitersystem (14), wobei die Feldsensoren auf zwei unterschiedlichen Radien (Rl, R2) um die Mitte des Mehrleitersystems (14) angeordnet sind, und:15. A method for evaluating at least two electrical signals from at least two field sensors (3, 4) in a Sig ¬ nalauswertevorrichtung (8) for determining a current strength of a current conductor (7) in a multi-conductor system (14), wherein the field sensors (on two different radii Rl, R2) are arranged around the center of the multi-conductor system (14), and:
- aus einem ersten Signal eine erste magnetische Feldstärke ( Hi ) und aus einem zweiten Signal eine zweite magnetische Feldstärke (H2) ermittelt wird und - From a first signal, a first magnetic field strength (Hi) and from a second signal, a second magnetic field strength (H 2 ) is determined and
- unter Verwendung des Gesetzes von Biot-Savart aus der Dif¬ ferenz der ersten und zweiten magnetischen Feldstärke ( Hi , H2) und aus einem ersten Abstand (5) zwischen dem ersten Feldsensor (3) und dem Stromleiter (7) oder aus einem zweiten Abstand (6) zwischen dem zweiten Feldsensor und dem Stromleiter (3) die Stromstärke des Stromleiters (3) ermittelt wird. - Using the law of Biot-Savart from the Dif ¬ ference of the first and second magnetic field strength (Hi, H 2 ) and from a first distance (5) between the first field sensor (3) and the current conductor (7) or from a second distance (6) between the second field sensor and the current conductor (3), the current strength of the conductor (3) is determined.
EP17765397.9A 2016-09-09 2017-09-06 Device and method for measuring the strength of the current an individual conductor of a multi-conductor system Pending EP3491398A1 (en)

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