CN114236224A - Transformer core grounding current measurement system and method - Google Patents
Transformer core grounding current measurement system and method Download PDFInfo
- Publication number
- CN114236224A CN114236224A CN202111535132.0A CN202111535132A CN114236224A CN 114236224 A CN114236224 A CN 114236224A CN 202111535132 A CN202111535132 A CN 202111535132A CN 114236224 A CN114236224 A CN 114236224A
- Authority
- CN
- China
- Prior art keywords
- magnetic
- grounding current
- current
- tmr
- transformer core
- 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
Links
Images
Classifications
-
- 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
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
-
- 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
Abstract
The invention provides a system and a method for measuring grounding current of a transformer core, which have the advantages of simple structure and reasonable arrangement, realize the miniaturization, high precision and low cost of the monitoring of the grounding current of the transformer core, and provide a technical basis for ensuring the safe and stable operation of power transformation equipment. The system comprises a grounding current acquisition sensor and a digital monitoring device; the grounding current acquisition sensor comprises a magnetic gathering ring with a gap, a single TMR magnetic resistance chip arranged in the gap, and a signal conditioning unit connected to the output end of the TMR magnetic resistance chip; the sensitive axis direction of the TMR magnetoresistive chip is the same as the magnetic flux direction of the magnetic gathering ring; the input end of the digital monitoring device is connected with the output end of the signal conditioning unit and used for monitoring the received signal. The invention relates to an advanced sensing technology based on a tunneling magnetoresistance effect, which is used for collecting current by adopting a magnetic gathering ring and measuring the current by converting the current into magnetic flux aiming at the practical application scene of a power grid.
Description
Technical Field
The invention relates to the field of weak current measurement of transformers, in particular to a system and a method for measuring grounding current of a transformer iron core.
Background
The transformer requires that the iron core is grounded at one point during normal operation, but due to the reasons of construction, operation aging, sundry deposition, insulation moisture, clamping piece collision caused by iron core displacement and the like, the transformer is grounded at multiple points. The multi-point grounding fault in the transformer can generate a closed loop, so that eddy current occurs in the iron core, iron loss is increased, the iron core and the transformer have faults such as overheating, clamp carbonization, iron core burnout, grounding wire burnout and the like, and the running safety of the transformer and even a power grid is seriously threatened.
The on-line monitoring current range of the grounding current of the transformer iron core or the clamping piece is 5 mA-10A; when the iron core normally operates, the grounding current is between 0mA and 100mA, when the current value is larger than or equal to 100mA, the iron core is indicated to have multipoint grounding faults, and local fault treatment is needed, otherwise serious accidents can be caused.
The traditional detection aiming at the faults of the transformer core is manual periodic inspection instead of real-time monitoring, the faults are not found timely enough, and the risk of accidents is still caused to a certain extent. The current real-time supervision device who installs except regularly patrolling and examining can in time monitor the iron core abnormal conditions, in time reports to the police when the trouble takes place, can compensate artifical periodic inspection's not enough to a certain extent, reduces transformer core earth fault's incidence.
The intelligent online monitoring device for grounding of the transformer core used by the current power system mostly adopts the Hall sensor as a core sensitive element, can greatly improve the sensitivity of current sampling, but the Hall current sensor is easy to be interfered by an external magnetic field, has large temperature drift and low measurement precision, and can not meet the high-precision measurement requirement of small current. In addition, a double sensor is used for overcoming the problem of low precision of the clamp-on ammeter caused by an open air gap, but the sensor is inconvenient to install and maintain due to the fact that the size of the device is too large due to structural limitation. The existing monitoring system has the defects of high price, overlarge device size, complex detection and the like, so that the existing monitoring system has certain limitation in practical application.
Currently, current sensors are typically based on the following 5 measurement techniques: HALL (HALL) current sensors; a fluxgate (fluxgate) current sensor; magnetoresistive (MR) current sensors including Anisotropic Magnetoresistance (AMR), Giant Magnetoresistance (GMR), Tunnel Magnetoresistance (TMR); rogowski coil (Rogowski coil) and current transformer (current transformer). There are current sensors of other indirect measurement techniques, mainly utilize the combination of magnetic field and other physics principle or effect, realize the indirect measurement of the electric current; including faraday-effect magneto-optical effect (magneto-optical), nuclear magnetic resonance NMR (nuclear-resonance), magnetostrictive effect (magnetostrictive effect), quantum Hall effect (quantum Hall effect), superconducting quantum interference device SQUID, etc. The technologies and products thereof have different characteristics aiming at different market segments. For example, current sensors based on NMR, quantum hall effect and SQUID have high requirements on application environment and high price, and are applied to laboratory instruments in small quantities, so far, part of the technology is still immature and is in the development or perfection stage; the current sensor based on the Faraday magneto-optical effect has better performance in measuring alternating current large current (such as 100kA), but the performance problem needs to be solved urgently when measuring direct current.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a transformer core grounding current measuring system and method, which are simple in structure and reasonable in arrangement, realize the miniaturization, high precision and low cost of transformer core grounding current monitoring, and provide a technical basis for ensuring the safe and stable operation of power transformation equipment.
The invention is realized by the following technical scheme:
a transformer core grounding current measuring system comprises a grounding current acquisition sensor and a digital monitoring device;
the grounding current acquisition sensor comprises a magnetic gathering ring with a gap, a single TMR magnetic resistance chip arranged in the gap, and a signal conditioning unit connected to the output end of the TMR magnetic resistance chip; the sensitive axis direction of the TMR magnetoresistive chip is the same as the magnetic flux direction of the magnetic gathering ring;
the input end of the digital monitoring device is connected with the output end of the signal conditioning unit and used for monitoring the received signal.
Preferably, the magnetism gathering ring is made of magnetic materials and is arranged in an opening and closing mode.
Preferably, the TMR magnetoresistive chip is provided with a positive power supply wiring port, a negative power supply wiring port, a signal output port, and a ground port, respectively.
Preferably, the signal conditioning unit comprises an amplifier, a filter, an analog-to-digital converter and a micro control unit which are connected in sequence.
Further, the amplifier adopts a differential operational amplifier.
Preferably, the digital monitoring device adopts an upper computer, and the input end of the digital monitoring device is connected with the output end of the signal conditioning unit through an RS-485 transmission line.
A method for measuring grounding current of a transformer core based on the measuring system comprises,
a wire to be tested is placed in the center of the magnetic gathering ring, the magnetic gathering ring gathers magnetic flux generated by current to be tested in the wire to be tested, a signal to be tested is output after being sensed by a single TMR magnetic resistance chip, and after being processed by the signal conditioning unit, a digital monitoring device outputs a signal waveform and monitors.
Preferably, the signal is processed by a signal conditioning unit, including amplification, filtering and analog-to-digital conversion.
Preferably, after the single TMR magnetoresistive chip is powered to work, the chip is placed in a magnetic field, analog differential signals are output at the V + pin of the positive power supply wiring port and the V-pin of the negative power supply wiring port, and the output signals and the magnetic field are in a linear relationship.
Compared with the prior art, the invention has the following beneficial technical effects:
the advanced sensing technology based on the tunneling magnetoresistance effect is used for collecting current and converting the current into magnetic flux for measurement by adopting the magnetic gathering ring aiming at the practical application scene of a power grid, so that on one hand, the accurate positioning of a TMR magnetoresistance chip is realized, and the interference of other non-to-be-measured magnetic fields is eliminated; the magnetic flux collecting device only collects the magnetic field generated by current without conversion through the magnetic collecting ring, converts the magnetic flux of the collected magnetic field into analog signals by utilizing the TMR magnetic resistance chip arranged in the gap, and respectively corresponds the collection and the conversion to different unit structures; the method has the advantages that the large dynamic range and high-precision real-time monitoring of the grounding current of the transformer iron core is realized, and the timeliness of the iron core multipoint ground fault detection is improved, so that the occurrence rate of the grounding fault of the transformer iron core is reduced, and the safety and the reliability of the operation of the transformer are improved.
Drawings
Fig. 1 is a block diagram of the operating principle of the system in the example of the invention.
Fig. 2 is a schematic diagram of the working structure of the system in the embodiment of the invention.
Fig. 3 is a schematic diagram of the magnetic field sensitivity direction of the TMR magnetoresistive chip in the embodiment of the present invention.
In the figure: the device comprises a grounding current acquisition sensor 1, an RS-485 transmission line 2, an upper computer 3 and a grounding wire 4.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
As used in this disclosure, "module," "device," "system," and the like are intended to refer to a computer-related entity, either hardware, a combination of hardware and software, or software in execution. In particular, for example, an element may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or a computer. Also, an application or script running on a server, or a server, may be an element. One or more elements may be in a process and/or thread of execution and an element may be localized on one computer and/or distributed between two or more computers and may be operated by various computer-readable media. The elements may also communicate by way of local and/or remote processes based on a signal having one or more data packets, e.g., from a data packet interacting with another element in a local system, distributed system, and/or across a network in the internet with other systems by way of the signal.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The invention provides a TMR magneto-resistive chip-based current measuring method for the field of random measurement, and aims to realize miniaturization, high precision and low cost of a current measuring terminal. Under the guidance of the principle, the grounding current measuring system utilizing the method is installed on a transformer core grounding wire or a grounding copper bar, so that the collection, storage, management and analysis of the grounding current data of the core are realized, the monitoring and prediction of the running state of the transformer can be completed, and the running state and possible faults of the transformer are judged according to the grounding current of the core.
The transformer grounding current measuring device based on the TMR chip adopts a single TMR chip measuring scheme according to the high sensitivity characteristic of the tunnel magnetic resistance chip, realizes the monitoring of the magnetic field and the current by the high sensitivity monitoring of the iron core grounding current, further improves the applicability of the transformer aiming at different voltage grades, and is beneficial to realizing the large-scale popularization of the method.
The invention relates to a transformer core grounding current measuring system, which comprises a grounding current acquisition sensor and a digital monitoring device;
the grounding current acquisition sensor comprises a magnetic gathering ring with a gap, a single TMR magnetic resistance chip arranged in the gap, and a signal conditioning unit connected to the output end of the TMR magnetic resistance chip; the sensitive axis direction of the TMR magnetoresistive chip is the same as the magnetic flux direction of the magnetic gathering ring;
the input end of the digital monitoring device is connected with the output end of the signal conditioning unit and used for monitoring the received signal.
The measuring system is divided into two parts, namely a grounding current acquisition sensor and a digital monitoring device. The grounding current acquisition sensor is a current sensor based on a tunneling magnetic resistance measurement principle.
The magnetic gathering ring is made of magnetic materials, is arranged in an opening-closing mode, is convenient to assemble and disassemble, is internally provided with a tunneling magnetic resistance chip, and is high in precision, wide in measurement frequency band, wide in measurement range, good in linearity, low in power consumption and light in weight. Specifically, the magnetism gathering ring comprises two parts, one end of each of the two parts is arranged in a clearance mode, the other end of each of the two parts is connected through a hinge, a hinge or other parts capable of being opened and closed, and the two parts can be opened and closed and then fixed; as shown in fig. 2, the transformer core is grounded via a ground wire, and the ground wire is placed in the center of the magnetic ring of the feedthrough sensor as a current-carrying wire. The output signal of the sensor is connected to a handheld upper computer through an RS-485 transmission line, and the waveform of the signal is controlled and output through upper computer software.
The measuring system and the measuring method are characterized in that current monitoring is carried out on a grounding round wire of a transformer core or a clamping piece or a grounding copper bar of the transformer core or the clamping piece, current data are gathered to an upper computer to be displayed, and the upper computer records the current data periodically so as to further explain the working state of the transformer.
The TMR magnetoresistive chip is provided with a positive power supply wiring port, a negative power supply wiring port, a signal output port and a ground port respectively; as shown in fig. 3, four electrical connection ports are led out from the grounding current collection sensor, which are respectively a positive power supply wiring port, a negative power supply wiring port, a signal output port and a ground port; the positive power supply wiring port is used for being connected with the positive wiring port of the excitation source, the negative power supply wiring port is used for being connected with the negative wiring port of the excitation source, the signal output port is used for outputting an electric signal of sensing conversion of the TMR magnetoresistive chip, and the ground port is used for being connected with a reference ground potential. The effective direction of the selected tunnel magnetoresistive chip to the magnetic field is the surface X-axis direction of the TMR device, as shown in FIG. 3.
As shown by a dotted line frame in fig. 1, the signal conditioning unit includes an amplifier, a filter, an analog-to-digital converter, and a micro control unit, which are connected in sequence. When the grounding current acquisition sensor works, magnetic flux is gathered through the magnetic gathering ring, a measured signal is output after being sensed by the sensitive TMR magnetic resistance chip, the measured signal is converted into a digital signal through a high-precision analog-to-digital converter after being processed by a signal conditioning circuit such as differential amplification and filtering, and the digital signal is processed and transmitted by a micro control unit MCU for main control. In the preferred embodiment, the amplifier is a differential operational amplifier. The digital monitoring device adopts an upper computer, and the input end of the digital monitoring device is connected with the output end of the signal conditioning unit through an RS-485 transmission line.
Specifically, when a single TMR magnetoresistive chip is used as a measuring device, the problems of random position and easy interference of a non-to-be-measured magnetic field exist, so that the measurement accuracy is greatly reduced, and the TMR magnetoresistive chip cannot be used for measuring the current in the field. In the invention, a signal of a current loop is connected into a tunneling magneto-resistance sensitive element based on tunneling magneto-resistance effect (TMR), namely a TMR magneto-resistance chip. The magnetic flux generated by the current to be tested is gathered by the magnetic gathering ring made of magnetic materials, the reluctance chip is placed in the gap of the magnetic gathering ring along the sensitive axis direction of the reluctance chip, and the wire to be tested is placed in the center of the magnetic gathering ring.
In the past, the leakage current collecting device based on the leakage current collecting ring converts the leakage current into voltage through the collecting ring to measure, and has the conversion function. The magnetic gathering ring of the system is only used for current collection, and the current can be directly measured through the tunneling magneto-resistance sensitive device. There are essential differences in the measurement principle.
The invention also provides a method for measuring the grounding current of the transformer core, which utilizes the measuring system, a lead to be measured is arranged in the center of the magnetic gathering ring, the magnetic gathering ring gathers magnetic flux generated by the current to be measured in the lead to be measured, a signal to be measured is output after being induced by the single TMR magnetic resistance chip, and after being processed by the signal conditioning unit, the signal waveform is output and monitored by the digital monitoring device. When the single TMR magnetoresistive chip is powered and works, the chip is placed in a magnetic field, analog differential signals can be output at the V + pin and the V-pin, and the output signals and the magnitude of the magnetic field form a linear relation; in the method, a voltage source is adopted for supplying power, so that two ports are needed, one is a positive port V +, and the other is a negative port V-, and a voltage signal V is produced together.
Aiming at the requirement of monitoring grounding current of a transformer core, the running state of equipment is sensed in real time, and the characteristic of high sensitivity of a TMR chip is utilized to realize a method for measuring current by adopting a single TMR chip. The method is used for transformer core grounding wires with different voltage levels, has certain universality, and can further expand the application scene of the method by monitoring integration aiming at temperature, displacement and noise.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (9)
1. A transformer core grounding current measuring system is characterized by comprising a grounding current acquisition sensor and a digital monitoring device;
the grounding current acquisition sensor comprises a magnetic gathering ring with a gap, a single TMR magnetic resistance chip arranged in the gap, and a signal conditioning unit connected to the output end of the TMR magnetic resistance chip; the sensitive axis direction of the TMR magnetoresistive chip is the same as the magnetic flux direction of the magnetic gathering ring;
the input end of the digital monitoring device is connected with the output end of the signal conditioning unit and used for monitoring the received signal.
2. The transformer core grounding current measuring system as claimed in claim 1, wherein the magnetic gathering ring is made of magnetic material and is disposed in an open-close manner.
3. The transformer core grounding current measuring system according to claim 1, wherein the TMR magnetoresistive chip is provided with a positive power supply wiring port, a negative power supply wiring port, a signal output port and a ground port, respectively.
4. The transformer core grounding current measuring system according to claim 1, wherein the signal conditioning unit comprises an amplifier, a filter, an analog-to-digital converter and a micro control unit which are connected in sequence.
5. The transformer core grounding current measuring system according to claim 4, wherein the amplifier is a differential operational amplifier.
6. The transformer core grounding current measuring system of claim 1, wherein the digital monitoring device adopts an upper computer, and the input end of the digital monitoring device is connected with the output end of the signal conditioning unit through an RS-485 transmission line.
7. A transformer core grounding current measuring method, characterized in that based on the measuring system of any one of claims 1-6, comprising,
a wire to be tested is placed in the center of the magnetic gathering ring, the magnetic gathering ring gathers magnetic flux generated by current to be tested in the wire to be tested, a signal to be tested is output after being sensed by a single TMR magnetic resistance chip, and after being processed by the signal conditioning unit, a digital monitoring device outputs a signal waveform and monitors.
8. The method for measuring the grounding current of the iron core of the transformer according to claim 7, wherein the signal conditioning unit processes the grounding current, and comprises amplification, filtering and analog-to-digital conversion.
9. The method for measuring the grounding current of the iron core of the transformer according to claim 7, wherein after the single TMR magnetoresistive chip is powered on, the chip is placed in a magnetic field, analog differential signals are output at a positive power supply wiring port V + pin and a negative power supply wiring port V-pin, and the output signals are in a linear relation with the magnitude of the magnetic field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111535132.0A CN114236224A (en) | 2021-12-15 | 2021-12-15 | Transformer core grounding current measurement system and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111535132.0A CN114236224A (en) | 2021-12-15 | 2021-12-15 | Transformer core grounding current measurement system and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114236224A true CN114236224A (en) | 2022-03-25 |
Family
ID=80756388
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111535132.0A Pending CN114236224A (en) | 2021-12-15 | 2021-12-15 | Transformer core grounding current measurement system and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114236224A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115541984A (en) * | 2022-11-30 | 2022-12-30 | 中国电力科学研究院有限公司 | Self-adaptive weak current monitoring device and monitoring method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206818777U (en) * | 2017-04-20 | 2017-12-29 | 广西电网有限责任公司电力科学研究院 | A kind of main transformer core earth current monitoring device |
| CN111650429A (en) * | 2020-06-03 | 2020-09-11 | 珠海多创科技有限公司 | Magnetic sensing chip, temperature compensation current sensor and preparation method thereof |
| CN112834805A (en) * | 2021-01-04 | 2021-05-25 | 中国电力科学研究院有限公司 | Tunneling magnetic resistance current sensor with position error calibration function and calibration method |
| CN112881943A (en) * | 2021-03-01 | 2021-06-01 | 中国电力科学研究院有限公司 | Insulator leakage current measuring device based on tunnel magnetic resistance chip |
-
2021
- 2021-12-15 CN CN202111535132.0A patent/CN114236224A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206818777U (en) * | 2017-04-20 | 2017-12-29 | 广西电网有限责任公司电力科学研究院 | A kind of main transformer core earth current monitoring device |
| CN111650429A (en) * | 2020-06-03 | 2020-09-11 | 珠海多创科技有限公司 | Magnetic sensing chip, temperature compensation current sensor and preparation method thereof |
| CN112834805A (en) * | 2021-01-04 | 2021-05-25 | 中国电力科学研究院有限公司 | Tunneling magnetic resistance current sensor with position error calibration function and calibration method |
| CN112881943A (en) * | 2021-03-01 | 2021-06-01 | 中国电力科学研究院有限公司 | Insulator leakage current measuring device based on tunnel magnetic resistance chip |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115541984A (en) * | 2022-11-30 | 2022-12-30 | 中国电力科学研究院有限公司 | Self-adaptive weak current monitoring device and monitoring method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6026355A (en) | Solid state watt-hour meter using GMR sensor | |
| US9817038B2 (en) | Electro-optic current sensor with high dynamic range and accuracy | |
| US9341653B2 (en) | Optical sensor assembly for installation on a current carrying cable | |
| CN103575960B (en) | giant magnetoresistance effect current sensor | |
| US10006944B2 (en) | Electro-optic current sensor with high dynamic range and accuracy | |
| CN109060938A (en) | Wirerope magnetic flux defects detection sensor | |
| CN114236224A (en) | Transformer core grounding current measurement system and method | |
| CN102156214B (en) | Double-light-path leakage current optical fiber sensor device | |
| CN113252960A (en) | External magnetic field interference suppression method suitable for direct-current power distribution network current sensor | |
| CN114778920A (en) | Single-magnetic-ring double-range high-precision closed-loop current sensor | |
| CN212903306U (en) | Multi-physical quantity synchronous monitoring device for transformer | |
| CN101923152B (en) | Room temperature calibration method for equivalent error area of gradiometer | |
| Chen et al. | Giant Magneto-Resistive (GMR) Sensors for Non-Contacting Partial Discharge Detection | |
| Qian et al. | Design of a nonintrusive current sensor with large dynamic range based on tunneling magnetoresistive devices | |
| Fan et al. | A Wide Range Current Sensing Device Based on Tunnel Junction Magnetoresistance Sensor for Power Transmission Line Monitoring | |
| WO2014014495A1 (en) | Optical sensor assembly for installation on a current carrying cable | |
| Bi et al. | Power system transient current sensor based on magnetoresistance effect | |
| CN116908515B (en) | Differential optical current sensor for lightning current detection | |
| Wang et al. | Position deviation analysis and correction method of tunnelling magnetoresistance sensor used in transformer core earthing current monitoring | |
| He et al. | High sensitive magnetic sensor with amorphous wire | |
| Bosselmann et al. | Intrinsic temperature compensation of magneto-optic AC current transformers with glass ring sensor head | |
| Zhang et al. | Design of open and close magnetic core weak current sensor based on tunneling magnetoresistance | |
| CN219811394U (en) | Magnetic core and coil assembly based on TMR weak current sensor | |
| Zhou et al. | A New Method to Design Power Meter Based on GMR Sensor | |
| Yang et al. | Research on High-Frequency Current Sensor and Measurement Method Based on Magnetic Sensor Array |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |