CN110609163A - Non-invasive current and voltage metering device - Google Patents
Non-invasive current and voltage metering device Download PDFInfo
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- CN110609163A CN110609163A CN201910931279.8A CN201910931279A CN110609163A CN 110609163 A CN110609163 A CN 110609163A CN 201910931279 A CN201910931279 A CN 201910931279A CN 110609163 A CN110609163 A CN 110609163A
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- 230000006698 induction Effects 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 5
- 239000003990 capacitor Substances 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 4
- 230000005641 tunneling Effects 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 22
- 230000005540 biological transmission Effects 0.000 abstract description 4
- 239000004020 conductor Substances 0.000 abstract description 4
- 230000005684 electric field Effects 0.000 abstract description 2
- 238000009434 installation Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 4
- 230000004907 flux Effects 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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- 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
- G01R15/12—Circuits for multi-testers, i.e. multimeters, e.g. for measuring voltage, current, or impedance at will
-
- 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
- G01R15/16—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using capacitive 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
- G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
-
- 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
- G01R15/205—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 magneto-resistance devices, e.g. field plates
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention relates to a non-invasive current and voltage metering device, which is arranged on a cable for current and voltage to be measured; the method is characterized in that: comprises a printed circuit, a capacitance type inductor and a magnetic induction device; the invention adopts a non-invasive and non-electric measurement mode to measure the conditions of power transmission, power distribution and power consumption by measuring the electric field and the magnetic field around the power-carrying lead; the installation and the use of the device do not affect the normal work of power transmission and distribution or power utilization sides; the device does not require physical contact to the current carrying conductor; the device for measuring the magnetic field can support the measurement of high-frequency bandwidth and is compatible with the measurement of direct current and alternating current.
Description
Technical Field
The invention relates to the field of power measurement, in particular to a non-invasive current and voltage metering device.
Background
The current measurement is divided into an invasive method and a non-invasive method, the invasive current measurement is based on the ohm law, and has the advantages of low cost, high precision, small volume, obvious defect, large temperature drift, difficult selection of precision resistor and no isolation effect. The non-invasive current measurement mainly comprises methods such as a current transformer and a Hall sensor. The current transformer is the most widely used current measuring mode in the electric energy metering device in China at present.
The current transformer mainly comprises a primary winding, a secondary winding, an iron core, insulation between the windings and the iron core and a shell, and the working principle is similar to that of a transformer; the current transformer has simple principle and convenient use, can measure very large current, consumes little power and is the inductor which is used most in the current large-current electronic electric energy meter. The normal output of domestic mature commercial products is 5A or 1A, and the electromagnetic relay can provide enough driving capability.
However, because these products can only test some lines of low voltage and low voltage in low altitude, but the existing current transformer has the problems of small dynamic range, narrow frequency band, poor anti-interference performance and poor measurement accuracy in the overall measurement of current and voltage in the high voltage and high current circuit in high altitude.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a device for measuring current and voltage in an intrusive mode, which can solve the problems of inconvenience brought by traditional intrusive current and voltage measurement and the problems of small measurement dynamic range, narrow frequency band, poor anti-interference performance and poor measurement accuracy of the current transformer adopted by the existing non-intrusive current and voltage measurement.
In order to solve the technical problems, the technical scheme of the invention is as follows: a non-invasive current and voltage measuring device is arranged on a cable for measuring current and voltage; the innovation points are as follows: comprises a printed circuit, a capacitance type inductor and a magnetic induction device;
the capacitance type inductor and the magnetic induction device are both arranged on a printed circuit, and an analog signal processing circuit is arranged on the printed circuit; the capacitance type inductor is provided with a pair of capacitors and is respectively positioned on a zero line and a live line of the current to be measured; the magnetic induction device comprises at least one magnetic inductor.
Furthermore, the magnetic induction device comprises a magnetic inductor, a magnetic core, an auxiliary variable coil, an amplifier and an auxiliary variable coil driver; the magnetic core is of a circular ring structure, a gap is formed in the magnetic core, the magnetic inductor is arranged at the gap of the magnetic core, and the auxiliary variable coil is wound on the magnetic core; one end of the amplifier is connected with the magnetic inductor through a wire, the other end of the amplifier is connected with one end of the auxiliary variable coil driver, the other end of the auxiliary variable coil driver is connected to one end of the auxiliary variable coil, the other end of the auxiliary variable coil is connected to the printed circuit, and a load resistor is connected to a circuit, connected with the printed circuit, of the auxiliary variable coil in parallel.
Further, the number of the magnetic inductors in the magnetic induction device is two, the distance between the pair of magnetic inductors is fixedly arranged, and the pair of magnetic inductors are arranged on the printed circuit board.
Further, the magnetic inductor is a giant magneto-resistance GMR or tunneling magneto-resistance TMR magnetic field inductor.
The invention has the advantages that:
1) The invention adopts a non-invasive and non-electric measurement mode to measure the conditions of power transmission, power distribution and power consumption by measuring the electric field and the magnetic field around the power-carrying lead; the installation and the use of the device do not affect the normal work of power transmission and distribution or power utilization sides; the device does not require physical contact to the current carrying conductor; the device for measuring the magnetic field can support the measurement of high-frequency bandwidth and is compatible with the measurement of direct current and alternating current.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a block diagram of an apparatus for non-invasively measuring current and voltage in example 1.
Fig. 2 is a circuit diagram of the connection of the apparatus for non-invasive measurement of current and voltage in example 1.
Fig. 3 is a structural diagram of an apparatus for non-invasively measuring current and voltage in example 2.
FIG. 4 is a diagram of second order gradient of magnetic field strength in a non-invasive current and voltage metering device of the present invention.
FIG. 5 is a graph of magnetic induction distribution measurements for a non-invasive current and voltage measuring device according to the present invention.
FIG. 6 is a voltage measurement schematic of a non-invasive current and voltage metering device of the present invention.
Detailed Description
The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the scope of the embodiments described herein.
Example 1:
a non-intrusive current and voltage metering device as shown in fig. 1, which is installed on a cable for current and voltage to be measured; comprising a printed circuit 1, a capacitive inductor 2 and magnetic induction means 3.
The capacitance type inductor 2 and the magnetic induction device 3 are both arranged on the printed circuit 1, and an analog signal processing circuit is arranged on the printed circuit 1; the capacitance type inductor 2 is provided with a pair of capacitors and is respectively positioned on a zero line and a live line of the current to be measured.
The magnetic induction device 3 comprises a magnetic inductor 31, and the magnetic induction device 3 further comprises a magnetic core 32, an auxiliary variable coil 33, an amplifier 34 and an auxiliary variable coil driver 35; the magnetic core 32 is of a circular ring structure, a notch is formed in the magnetic core 32, the magnetic inductor 31 is arranged at the notch of the magnetic core 32, and the auxiliary transformer coil 33 is wound on the magnetic core 32; one end of the amplifier 34 is connected with the magnetic inductor 31 through a conducting wire, the other end of the amplifier 34 is connected with one end of the auxiliary variable coil driver 35, the other end of the auxiliary variable coil driver 35 is connected to one end of the auxiliary variable coil 33, the other end of the auxiliary variable coil 33 is connected to the printed circuit 1, and a load resistor 36 is connected to a circuit, connected with the printed circuit 1, of the auxiliary variable coil 33 in parallel.
The magnetic sensor 31 is a giant magneto-resistive GMR or tunneling magneto-resistive TMR magnetic field sensor.
The working principle is as follows:
The device adopts the magnetic balance measurement principle, the primary side current Is recorded as Ip, namely the measured current, a generated magnetic field Is generated in a soft magnetic material, a magnetic inductor outputs a certain electric signal, the electric signal passes through an amplifier to drive an auxiliary transformer coil, the number of turns Is recorded as Ns to generate an auxiliary side current which Is recorded as Is and has the direction opposite to that of the primary side current, the amplifier can force the auxiliary side current to offset the magnetic field generated by the primary side current, so that under the condition that offset voltage Is zero, the magnetic field in the magnetic core Is 0, and the auxiliary side current and the primary side current have the following relation,
Is = − Ip/Ns
in practice, however, all wheatstone bridge devices have a certain offset voltage, and the soft magnet may have a certain residual magnetic flux, the secondary current output will have the following relationship,
Is = − Ip/Ns- (BrS +α)/ SβNs
br residual magnetic flux density (G)
S: sensitivity of magnetic inductor (mV/V/G)
Offset voltage (mV/V)
Beta. magnetic core coefficient (G/A)
The primary current Ip can be calculated according to the above formula.
The offset voltage due to the unbalance of the resistance and the residual magnetic flux must be controlled within a certain range and compensated by a dc voltage. The magnitude of the DC voltage can be calibrated before factory shipment.
Example 2:
a non-invasive current and voltage measuring device as shown in fig. 2, which is installed on a cable for measuring current and voltage, comprises a printed circuit 1, a capacitive inductor 2 and a magnetic induction device 3;
the capacitance type inductor 2 and the magnetic induction device 3 are both arranged on the printed circuit 1, and an analog signal processing circuit is arranged on the printed circuit 1; the capacitance type inductor 2 is provided with a pair of capacitors and is respectively positioned on a zero line and a live line of the current to be measured.
The number of the magnetic inductors in the magnetic induction device 3 is two, the distance between the pair of magnetic inductors 31 is fixedly set, and the pair of magnetic inductors 31 is mounted on the printed circuit board.
The magnetic sensor 31 is a giant magneto-resistive GMR or tunneling magneto-resistive TMR magnetic field sensor.
The working principle is as follows:
The device adopts a gradient measurement method, a magnetic field attenuates along with the distance between a measuring point and a conductor, when an interference current source is arranged at the periphery of the measuring point, the measured reading is influenced by an interference source, the degree of influence is related to the attenuation speed of the magnetic field, the relative influence degree is smaller if the magnetic field attenuates faster, and the attenuation speed of the magnetic field gradient is far greater than the attenuation speed of the magnetic field along with the distance, which is shown in figure 4. The invention adopts the measurement of the magnetic field gradient of the second order to reduce or eliminate the influence of an external current source and a magnetic field source on the measurement. The concrete formula is as follows,
the distance of the measuring point from the measured conductor is: r1, at a distance, R2,
generally, R2 > R1;
magnetic field second order gradient signal-to-interference ratio: (R2/R1) has been completed.
For the single wire as shown in fig. 5, its magnetic field distribution is nearly infinitely extended for a straight wire pattern, according to Biot-Savart's law, B1= I/2 tr; b2 = I/2 pi (r + d), and the magnetic field readings B1 and B2, the mutual distance d of the two sensors, are known during calibration. (ii) a The current I and the original distance r are unknown, which can be calculated from the readings measured by the two sensors.
It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (4)
1. A non-invasive current and voltage measuring device is arranged on a cable for measuring current and voltage; the method is characterized in that: comprises a printed circuit, a capacitance type inductor and a magnetic induction device;
the capacitance type inductor and the magnetic induction device are both arranged on a printed circuit, and an analog signal processing circuit is arranged on the printed circuit; the capacitance type inductor is provided with a pair of capacitors and is respectively positioned on a zero line and a live line of the current to be measured; the magnetic induction device comprises at least one magnetic inductor.
2. The apparatus of claim 1 for non-invasively metering current and voltage, wherein: the magnetic induction device comprises a magnetic inductor, a magnetic core, an auxiliary variable coil, an amplifier and an auxiliary variable coil driver; the magnetic core is of a circular ring structure, a gap is formed in the magnetic core, the magnetic inductor is arranged at the gap of the magnetic core, and the auxiliary variable coil is wound on the magnetic core; one end of the amplifier is connected with the magnetic inductor through a wire, the other end of the amplifier is connected with one end of the auxiliary variable coil driver, the other end of the auxiliary variable coil driver is connected to one end of the auxiliary variable coil, the other end of the auxiliary variable coil is connected to the printed circuit, and a load resistor is connected to a circuit, connected with the printed circuit, of the auxiliary variable coil in parallel.
3. The apparatus of claim 1 for non-invasively metering current and voltage, wherein: the magnetic inductor among the magnetic induction device has two, the interval fixed setting between this pair of magnetic inductor, this is installed on printed circuit to the magnetic inductor.
4. The apparatus of claim 1 for non-invasively metering current and voltage, wherein: the magnetic inductor is a giant magneto-resistance GMR or tunneling magneto-resistance TMR magnetic field inductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910931279.8A CN110609163A (en) | 2019-09-29 | 2019-09-29 | Non-invasive current and voltage metering device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910931279.8A CN110609163A (en) | 2019-09-29 | 2019-09-29 | Non-invasive current and voltage metering device |
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| CN110609163A true CN110609163A (en) | 2019-12-24 |
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| CN201910931279.8A Pending CN110609163A (en) | 2019-09-29 | 2019-09-29 | Non-invasive current and voltage metering device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113533825A (en) * | 2021-07-14 | 2021-10-22 | 郑州信工智能化系统有限公司 | Current measurement method capable of eliminating common-mode interference based on magnetoresistive sensor |
| CN116539942A (en) * | 2023-07-06 | 2023-08-04 | 深圳市知用电子有限公司 | Magnetic flux detection system and current sensor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244106A (en) * | 2019-06-23 | 2019-09-17 | 上海千贯节能科技有限公司 | A kind of equipment of non-intrusion type metering current and voltage |
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- 2019-09-29 CN CN201910931279.8A patent/CN110609163A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244106A (en) * | 2019-06-23 | 2019-09-17 | 上海千贯节能科技有限公司 | A kind of equipment of non-intrusion type metering current and voltage |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113533825A (en) * | 2021-07-14 | 2021-10-22 | 郑州信工智能化系统有限公司 | Current measurement method capable of eliminating common-mode interference based on magnetoresistive sensor |
| CN116539942A (en) * | 2023-07-06 | 2023-08-04 | 深圳市知用电子有限公司 | Magnetic flux detection system and current sensor |
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