DE102011017761A1 - Method and device for line detection - Google Patents

Abstract

A method for finding an alternating voltage-carrying conductor comprises steps of detecting an electric field at a first measuring location, detecting a magnetic field at the first measuring location, determining a temporal offset between the detected fields, comparing the determined offset with a reference offset and the output of a reference to the conductor depending on the comparison. A device for locating an alternating-voltage conductor comprises a first sensor for detecting an electric field at a first measuring location, a second sensor for detecting a magnetic field at the first measuring location, a processing device for determining a time offset between the detected fields and an output device for outputting a reference to the ladder. The processing device is set up to control the output device as a function of a comparison of the determined offset with a reference offset.

Description

The invention relates to a technique for finding an AC-carrying conductor. In particular, the invention relates to a technique for finding an AC-carrying conductor based on a time offset of components of a complex vector.

State of the art

Line finders are known which operate on the basis of an electrical, capacitive or magnetic field. Each of the three measurement principles has its individual strengths for detecting a piece of metal, a live conductor or other metallic obstruction hidden in, for example, a house wall to be found, for example, to avoid damaging the obstruction when drilling a hole in the house wall , Wire seekers are also known which combine several of the mentioned measuring principles, for example in order to achieve an improved resolution or a clearer measurement.

The invention has for its object to provide a technique for further improved finding an alternating voltage-carrying conductor.

The invention achieves the object by means of a method having the features of claim 1, a computer program product having the features of claim 6, a device having the features of claim 7 and a system having the features of claim 8. Subclaims reflect preferred embodiments.

Disclosure of the invention

The method according to the invention, or a device according to this method, enables a better detection of lines which are at usual voltages of, for example, 110V / 220V / 380V, or also low-voltage lines.

The essence of the invention is to measure the magnetic field representing a complex vector corresponding to the complex current through the line and to relate it to the measured electric field defining the real axis. If you consciously let a complex current flow through the lines to be detected, with a known angle to the real axis (E-field), then this stream can be distinguished from other streams and thus the line from other lines.

An inventive method for finding an AC-carrying conductor comprises steps of detecting an electric field at a first measurement location, detecting a magnetic field at the first measurement location, determining a time offset between the detected fields, comparing the determined time offset with a reference offset and outputting an indication of the conductor depending on the comparison. As will be understood by one of ordinary skill in the art, the time offset may be expressed equivalently as absolute time or as phase angle with respect to an alternating frequency of the electric and magnetic fields, respectively. In the context of this application, the temporal offset always means the image of the phase angle between the electric and magnetic fields.

According to the invention, it is possible to detect the alternating voltage-carrying conductor both on the basis of the determined time offset and to identify it under a plurality of conductors in the region of the measuring location. By appropriate choice of the reference offset, the reference to the conductor, for example, be given if the offset indicates an open line, that is, on a line through which no active current flows. In another embodiment, a time offset associated with a particular AC line conductor may be known. If the specific time offset corresponds to the reference offset with sufficient accuracy, it can be assumed that the required conductor is located in the area of the measuring location. In this way, it is possible to locate the particular conductor without being influenced by any other live conductors carrying the alternating current.

In a further embodiment of the method, a time offset between the detected fields at a known frequency, such as 50 Hz or 60 Hz, can also be compared with a reference value. Thus, the reference to the leader can be generated based on the same information without formally determining the phase.

The temporal reference offset may be determined in at least two different ways. In a first variant, an electric field is detected at a second measuring location in the region of the conductor, a magnetic field is detected at the second measuring location, and the reference offset is determined on the basis of the fields detected at the second measuring location. The reference offset determined in this way encompasses all potential measurement errors that may influence an otherwise determination of the reference offset. Tracking the conductor or identifying another section of the conductor can thereby be facilitated.

In a second variant, during the detection of the fields, a current can be generated by the conductor, which includes the reference offset with the AC voltage at the conductor. In this case, the temporal reference offset can be selected so that it differs from a time offset between current and voltage of another conductor. This can help to make a mapping of a site to the area of the leader less vulnerable. In one embodiment, the electrical and magnetic fields are detected sequentially. Depending on the measuring method of the electric and the magnetic field mutual interference can thus be avoided. Alternatively, the electric and magnetic fields can also be detected simultaneously. This can make it easier to ensure that the relevant measuring location for the magnetic field is the same measuring location as that for the electric field.

Preferably, the first measurement location along the ac voltage-carrying conductor is shifted on the basis of the hint. The signal indicative of the conductor may be configured to indicate to a user that the measurement site is being removed or stitched to the conductor. A course of the conductor can be tracked in a simple and reliable way. This may make it possible, for example, to correct or complete an incomplete or incorrect circuit diagram of an installation.

According to a further aspect, a computer program product comprises program code means for carrying out the method described, when it runs on a processing device or is stored on a computer-readable data carrier.

According to yet another aspect, the invention relates to a device for finding an alternating voltage-carrying conductor, wherein the device comprises a first sensor for detecting an electric field at a first measuring location, a second sensor for detecting a magnetic field at the first measuring location, a processing device for determining a time offset between the detected fields and an output device for outputting an indication of the conductor. The processing device can determine the time offset as the absolute time or based on an alternating frequency of the electric or magnetic field as the phase angle. Furthermore, the processing device is set up to control the output device in dependence on a comparison of the determined phase angle with a predetermined time reference offset.

On the one hand, the device can be used to find the alternating voltage-carrying line. On the other hand, the device may also be used to identify a particular AC-carrying conductor among a plurality of AC-conducting conductors or to locate different portions of the conductor. In particular, by means of the device, an extension of the conductor can also be determined when the conductor is hidden, for example as a conduit running inside a wall of a building.

According to yet another aspect of the invention, a system for detecting an AC-carrying conductor includes the described device and means for generating a current through the conductor, the current including the AC voltage at the conductor including the reference offset. By selecting a characteristic reference offset, the identification of the conductor can be further facilitated.

The device can actively or passively establish the reference offset between current and voltage. In one embodiment, the device includes a complex electrical resistance for connection to the conductor. Since the conductor carries an AC voltage, after connecting the complex electrical resistance to the conductor, a complex current flows whose components include the reference offset with each other. Thus, the advantages of finding the conductor based on the time lag between current and voltage or on the basis of the phase angle between electric field and magnetic field can be combined with the advantages of a transmitter-receiver system for finding the conductor.

In a particularly preferred, simple embodiment, the complex electrical resistor comprises an inductance and / or a capacitor. The device can be constructed in this way particularly simple and inexpensive.

Brief description of the figures

The invention will now be described in more detail with reference to the attached figures, in which:

1 a device for finding an alternating voltage-carrying conductor;

2 a graphical representation of a phase angle;

3 a system for finding an AC-carrying conductor; and

4 FIG. 5 is a flowchart of a method for finding an AC-carrying conductor. FIG.

Detailed description of embodiments

1 describes a device 100 for finding an alternating voltage-carrying conductor 105 , By the conductor 105 a current flows, leaving in the area of the conductor 105 an electric field E and a magnetic field B prevail. The device 100 includes an electric field sensor 110 , a magnetic field sensor 115 , a processing device 120 , a user interface 125 and a battery 130 , The processing device 120 is with the field sensors 110 and 115 as well as with the user interface 125 and the battery 130 connected.

The electric field sensor 110 may be formed in the form of a metallized surface. Depending on how strong the electric field E is, is in the electric field sensor 110 between the surface and a ground terminal causes a voltage supplied by the processing means 120 is sampled as a signal that is proportional to the electric field.

The magnetic field sensor 115 is adapted to determine the magnetic field B, which is geometrically perpendicular to the electric field E. If no consumer is operating in a circuit that is the conductor 105 includes, the magnetic field B can be very small; however, due to parasitic effects, the magnetic field B is practically always sufficiently large to pass through a sensitive magnetic field sensor 115 be metrologically detectable. For the magnetic field sensor 115 Different technologies can be used, for example a Hall sensor, a Förster probe, a GMR, AMR, CMR or TMR probe. It is also possible to use a magnetic field probe based on a field coil.

The electric field sensor 110 and the magnetic field sensor 115 are preferably close to each other, so that the specific electric field E and the specific magnetic field B are related to the same measuring location. Depending on the design of the processing device 120 and the field sensors 110 and 115 can the sensors 110 . 115 be driven alternately or simultaneously to determine the corresponding fields.

The user interface 125 has output and controls for a user of the device 100 on. An output can be made visually, acoustically and / or haptically. An input for operation can be made by means of a dedicated button or point. It may also be an advanced user interface, for example in the form of a graphic input and output, for which a graphical output device and a graphical input device may be combined approximately in the form of a touch-sensitive screen. It may also include a further interface, which is provided for data communication with another device. The further interface may be wired or wireless, such as a Bluetooth wireless or Wimax interface.

The processing device 120 and possibly the field sensors 110 respectively. 115 are preferably from the battery 130 or a similar electrical energy storage fed, which allows the fullest possible decoupling of a circuit, the conductor 105 includes.

The processing device 120 is preferably constructed on the basis of a programmable microcomputer and adapted to determine a time offset between the electric field E and the magnetic field B in the form of a time or a phase angle and the AC voltage carrying conductor 105 to identify on the basis of the determined time offset between the specific fields.

2 shows a diagram 200 with a representation of a phase angle at the conductor 105 out 1 , In the horizontal direction, a real part and in the vertical direction an imaginary part is plotted.

Is the leader 105 As part of an electrical circuit comprising a complex electrical resistance, as a function of the complex resistance, a phase angle φ arises between the voltage on the conductor 105 and the current through the conductor 105 one. The electric field E is proportional to the voltage at the conductor 105 and the magnetic field B is proportional to the current through the conductor 105 , The same phase angle φ therefore becomes between measured values of the field sensors that correspond to one another in time 110 and 115 locked in.

In the diagram 200 corresponds to a first vector 205 qualitatively a measured value of the electric field sensor 110 and a second vector 210 qualitatively a measured value of the magnetic field sensor 115 , The vectors 205 and 210 between them the phase angle φ. It should be noted that the phase relationship between the vectors 205 and 210 or the measured values of the sensors 110 and 115 temporal nature and is based on an alternating frequency of the AC voltage at the conductor 105 is applied.

In a graphic interpretation, the second vector exists 210 , which corresponds to the magnetic field B, from a first portion, in the course of Real axis of the chart 200 runs, and a second portion, which is in the direction of the imaginary axis of the diagram 200 runs. The vector 210 is formed by adding the first part to the second part. The first part is called active current, the second part reactive current. If the complex resistor comprises only an ohmic load, such as an electric grill, the reactive current is minimal, the active current maximum and the phase angle φ is approximately 0 °. Is the complex resistance infinitely large, for example in the case of an open line 105 , the reactive current is maximal, the active current is minimal and the phase angle φ is close to 90 °. Due to parasitic capacities and other, hardly avoidable effects in the area of the conductor 105 In general, the phase angle φ reaches neither 0 ° nor 90 ° completely.

In general, the complex resistor is a load that is a combination of an ohmic resistance, an inductive and / or a capacitive resistance, and the phase angle φ is somewhere between the described extremes.

It should be noted that the phase angle φ basically also at a very small current through the conductor 105 and sets a correspondingly small magnetic field E. The phase angle φ and the ratio between reactive current and active current is of the absolute magnitude of the current through the conductor 105 independently. In order to enable a reliable determination of the phase angle φ, it is helpful to use the first vector 205 or to determine the value of the electric field E as accurately as possible. For this purpose, the electric field sensor 110 be large enough to amplify a pointing to the electric field E signal. Even if the electric field sensor 110 Not necessarily suitable for overdimensioning. Accurately localizing a hidden AC line, the AC voltage can be reliably and robustly detected with the help of the E-field. The priority of the electric field sensor 110 lie in the method according to the invention in the clear definition of the real reference axis. The actual detection of the power line is then with the sensor 115 made for the magnetic field.

For the correct determination of the phase angle on the basis of the specific fields, the signals of the field sensors 110 and 115 multiplied by appropriate factors.

By evaluating the complex flow one is able to characterize different consumers. Starting from a load module that can generate deliberate and known phase angle between U / I, up to reactive currents z. B. are formed by the network capacity, and / or consumers of daily needs z. As electric heating, which can tile a purely real power.

3 shows a system 300 for finding the alternating voltage-carrying conductor 105 out 1 ,

The AC-live conductor 105 and a corresponding return conductor 305 run close together. This constellation is common in electrical supply lines, which are laid, for example, as part of a domestic installation in a wall. The leader 105 and the return conductor 305 are each at one end with an AC source 310 connected, which provides a substantially sinusoidal AC voltage. The alternating voltage can be, for example, 110 V at 60 Hz or 230 V at 50 Hz.

The system 300 includes the device 100 out 1 and a phase angle generator 315 with the other end of the conductor 105 or the return conductor 305 is connectable. In a preferred embodiment, the phase angle generator 315 built from passive components and forms a complex resistance, with neither real part nor imaginary part of the complex resistance is vanishingly small. The phase angle generator 315 may for example be constructed by means of an inductance or a capacitance, which is optionally in series with an ohmic resistance. Due to the AC voltage caused by the AC source 315 is provided causes the complex resistance of the phase angle generator 315 a complex current through the conductor 105 or the return conductor 305 , wherein the complex current with the voltage of the AC voltage source 310 includes the phase angle φ referred to above with reference to FIG 2 has been described in more detail.

The device 100 can now be in the area of the conductor 105 or the return conductor 305 be moved, for example between a first location 320 and a second location 325 so the field sensors 110 respectively. 115 the electric field E or the magnetic field B in the region of the conductor 105 respectively. 305 to capture. On the basis of the detected fields, the phase angle φ or the corresponding time offset of the fields is determined and compared with the reference phase angle between the current and the voltage of the conductors 105 . 305 by the design of the phase angle generator 315 is predetermined. Depending on the comparison is made on the device 100 outputting a signal, which then assists a user, the device 100 along the ladder 105 . 305 to move and thus the course of the ladder 105 . 305 out.

4 shows a flowchart of a method 400 for finding the alternating voltage-carrying conductor 100 respectively. 305 from the 1 or 3 , The procedure 400 begins with one of three possible variants for defining the temporal reference offset.

In a first variant, in one step 405 the sensors 110 . 115 to the second location 325 out 3 spent. The second measurement location is preferably at a point known to be close to the conductor 105 is, for example in the range of a connection for the phase angle generator 315 , Subsequently, in step 410 the electric field and in step 415 the magnetic field in the area of the conductor 105 detected. Based on the specific fields will be in one step 420 the reference phase angle or reference offset between the fields is determined.

In a second variant, in one step 425 the reference offset, for example, by means of the user interface 125 manually defined. In this case, an input can take place in the form of a time or in the form of a phase angle.

In a third variant, the temporal reference offset is in one step 430 already fixed. This variant is similar to the one above 3 explained approach in which by the phase angle generator 315 at least during the subsequent steps 440 and 445 of the procedure 400 the reference phase angle between the current and the voltage of the conductor 105 respectively. 305 is produced.

After the reference offset has been defined by one of the three specified variants, the sensors become 110 and 115 in one step 435 to the first location 320 spent. The following is to check if the leader 105 in the area of the first location 320 is or not. This is done in one step 440 the electric field at the first location 320 and in one step 445 the magnetic field at the first location 320 detected. The steps 440 and 445 can also be executed simultaneously or in reverse order. On the basis of the two specific fields will be in one step 450 the temporal offset, for example in the form of the phase angle φ determined. Subsequently, in one step 455 the particular offset compared to the previously determined reference offset.

Depending on the comparison, in one step 460 a signal to a user of the device 100 output. The signal may indicate that the offset is no more than a predetermined amount different from the reference offset. In another embodiment, the signal may also indicate that there is greater than a predetermined difference between the skew and the reference skew. In one embodiment, a window comparison may also be performed as to whether the particular temporal offset is between a first and a second reference offset, both of which are each by means of one of the three variants given above in the steps 405 to 430 were defined.

• – Anzeige (Display, LEDs, usw.) zur Darstellung vom Messwerten
• – Backlight zur Beleuchtung der Anzeige
• – Schnittstelle HMI, beispielsweise in Form einer Tastatur oder eines Touch-Displays
• – Auto-Aus-Funktion zur Energieeinsparung, die nach einem vorgegebenen oder vorgebbaren Zeitpunkt nach Durchführung der letzten Messung, das Messgerät ausschaltet oder in einen „Stand-by” Modus überführt
• – Batteriebetrieb/Akkubetrieb
• – Ladeelektronik mit einer Steuerung bzw. einer Regelung
• – Weggeber (Räder, Lichtschranken, Beschleunigungssensoren, optische Weggeber, usw.) die es ermöglichen, den vom Messgerät beispielsweise auf einer Wand zurückgelegten Weg zu detektieren, um so beispielsweise einem Messwert auch eine Ortskoordinate zuzuweisen
• – Kombination mit weiteren Sensoren Metall- und Studfinder und AC Sensoren, die ebenfalls im Gehäuse des Messgerätes vorgesehen sein können
• – Bluetooth/WLAN Schnittstelle zur Datenübertragung oder auch zur Aktivierung des Gerätes

The device according to the invention 100 , which is designed in particular as a hand-held measuring device, has a housing and moreover optionally or alternatively at least one of the following features:

• - Display (display, LEDs, etc.) to display the measured values
• - Backlight to illuminate the display
• - Interface HMI, for example in the form of a keyboard or a touch display
• - Auto-off function for energy saving, which switches off the meter or puts it in a "stand-by" mode after a specified or predefinable time after the last measurement has been made
• - Battery operation / battery operation
• - charging electronics with a controller or a scheme
• - Displacement sensors (wheels, photoelectric sensors, acceleration sensors, optical displacement sensor, etc.) which make it possible to detect the path traveled by the meter, for example, on a wall, so as to assign, for example, a measured value and a location coordinate
• - Combination with other sensors metal and Studfinder and AC sensors, which can also be provided in the housing of the meter
• - Bluetooth / WLAN interface for data transfer or activation of the device

Claims (10)

Procedure ( 400 ) for finding an AC-conducting conductor ( 105 . 305 ), comprising the following steps: - detecting ( 440 ) of an electric field (E) at a first measuring location ( 320 ); - To capture ( 445 ) of a magnetic field (B) at the first measuring location ( 320 ); - Determine ( 450 ) a time offset (φ) between the detected fields; - To compare ( 455 ) of the determined time offset (φ) with a reference offset; and - spend ( 460 ) a reference to the leader ( 105 . 305 ) depending on the comparison. Procedure ( 400 ) according to claim 1, wherein determining the reference offset comprises the steps of: - detecting ( 410 ) of an electric field (E) at a second measuring location ( 325 ) in the area of the conductor ( 105 . 305 ); - To capture ( 415 ) of a magnetic field (B) at the second measuring location ( 325 ); - Determine ( 420 ) of the reference offset on the basis of the second measurement location ( 325 ) fields. Procedure ( 400 ) according to claim 2, further comprising generating ( 430 ) of a current through the conductor ( 105 . 305 ) with the reference offset to the AC voltage on the conductor ( 105 . 305 ) while capturing ( 440 . 445 ) of the fields. Procedure ( 400 ) according to one of the preceding claims, wherein the electrical (E) and the magnetic field (B) are detected successively. Procedure ( 400 ) according to one of the preceding claims, further comprising a displacement of the first measuring location ( 320 ) along the AC-conducting conductor ( 105 . 305 ) on the basis of the hint. Computer program product with program code means for carrying out the method ( 400 ) according to one of the preceding claims, when stored on a processing device ( 120 ) or stored on a computer-readable medium. Contraption ( 100 ) for finding an AC-conducting conductor ( 105 . 305 ), comprising: - a first sensor ( 110 ) for detecting an electric field (E) at a first measuring location ( 320 ); A second sensor ( 115 ) for detecting a magnetic field (B) at the first measuring location ( 320 ); A processing device ( 120 ) for determining a time offset (φ) between the detected fields; and - an output device ( 125 ) to give a hint to the leader ( 105 . 305 ); - wherein the processing device ( 120 ) is adapted to the output device ( 125 ) in response to a comparison of the determined time offset (φ) with a reference offset. System ( 300 ) for finding an AC-conducting conductor ( 105 . 305 ), comprising a device ( 100 ) according to claim 7 and a device ( 315 ) for generating a current through the conductor ( 105 . 305 ), whereby the current with the AC voltage at the conductor ( 105 . 305 ) includes the reference offset. A system according to claim 8, wherein the device ( 315 ) a complex electrical resistance for connection to the conductor ( 105 . 305 ). System according to claim 9, wherein the complex electrical resistance ( 315 ) comprises an inductance and / or a capacitor.

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