CN112834811A - Ground current state monitoring method and device applying magnetic resistance sensing and storage medium - Google Patents
Ground current state monitoring method and device applying magnetic resistance sensing and storage medium Download PDFInfo
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Abstract
The invention provides a device, a method and a storage medium for monitoring the state of grounding current by applying magnetic resistance sensing, wherein a tunneling magnetic resistance sensor is used for realizing high-precision measurement of the current passing through a grounding wire, abnormal states such as grounding of electric equipment and the like are evaluated by using frequency spectrum components and current numerical values of sensed current signals in a digital signal analysis mode, an abnormal evaluation result is transmitted to a distribution room or a surrounding intelligent distribution terminal by waking up a LoRa wireless data transmission module, distribution fault automatic application is supported, distribution equipment fault warning information can also be transmitted to a power grid monitoring center through a distribution Internet of things system, the running states of a transformer, a reactor, a high-voltage sleeve and the like in the distribution room/transformer substation are remotely monitored, the grounding fault of the electric equipment is effectively prevented, and the safe running level of an intelligent unmanned transformer substation is improved.
Description
Technical Field
The invention belongs to the technical field of sensors, and particularly relates to a method and a device for monitoring a ground current state by applying magnetoresistive sensing, and a storage medium.
Background
The grounding current is an important operating condition index of many power equipment, such as the core grounding current of a transformer, and reflects the grounding problem of the core of the transformer during operation. Normally, the ground current is between a few milliamperes and tens of milliamperes. However, if the iron core has a multipoint ground fault, a current of several tens of amperes flows through the iron core, so that the iron core is locally overheated, and normal power supply of a power grid is affected.
The following problems generally exist in the current grounding current monitoring device: 1) the sensor fault rate is high, and according to statistics, more than half of faults in the on-line monitoring devices of the national transformers are sensor faults; 2) the sensing system has short service life, and because the sensing device needs to work in an outdoor environment for a long time, the sensing device needs to be powered by a battery, the service life of the sensing device is greatly dependent on the service life of the selected battery (generally, under a continuous working state, less than two years); 3) the effectiveness is poor, and the traditional monitoring device adopts a pincerlike mutual inductor and is easily influenced by a severe electromagnetic environment near a power transformer to generate false alarm; 4) the traditional monitoring device adopts a plurality of sensors to directly obtain current signals, the number of the sensors needed is too many, the volume and the weight of equipment are large, and the installation is inconvenient; 5) the economical efficiency of equipment is poor, the current iron core grounding current monitoring device is sold in a set of 2-5 ten thousand yuan in market, and the economical efficiency is poor compared with the equipment price of a transformer, so that the coverage rate of the iron core current monitoring device of the transformer is low (only 0.34%); 5) the data transmission communication difficulty is high, the electromagnetic environment near the power transformer equipment is severe, and the transmission success rate is low by adopting communication modes such as 485 bus, wireless and the like; distribution room, transformer substation etc. distribute according to the power supply demand, relative surveillance center is far away, the position dispersion, need consider the communication demand of unmanned on duty intelligent transformer substation. On the other hand, the current measurement of the ground current has the problems of high sensor fault rate, short device operation life, insufficient measurement accuracy, poor equipment economy and the like, and the application of the ground current sensing device is influenced by the problems.
Disclosure of Invention
Based on this, this patent is through adopting neotype magnetic resistance sensor technique, running state analysis and the abnormal evaluation technique based on signal processing and analysis, combines the structural design of integration, with sensor, information processing and analysis, power supply unit etc. are integrated together, reduces transmission, electromagnetic interference etc. that the unit increases separately and influences the risk, and the device design under the high integration degree, the electromagnetic shield of being convenient for, the promotion of mechanical stability, promote the reliability of system, solve the above-mentioned problem that exists in the present earth current sensor equipment measurement.
The embodiment of one aspect of the invention provides a ground current state monitoring method applying magnetic resistance sensing, which comprises the steps of carrying out quantization processing on an obtained sampling signal in a ground wire to obtain real-time waveform data of the sampling signal, wherein the real-time waveform data comprises effective values, peak values and real-time waveforms of fundamental waves and/or harmonic waves of the sampling signal;
calculating a current signal of the grounding conductor according to the real-time waveform data and a preset current relation model;
calculating an effective value of the current signal according to the obtained current signal; the effective values comprise an effective value of a current signal, an effective value of a fundamental wave and effective values of each harmonic wave, and the obtained effective value of the current is compared with a preset current threshold value;
if the current exceeds a preset current threshold and the collected current signal contains components higher than 2 harmonics, the ground fault is evaluated to be a ground fault with a partial discharge level;
and matching a preset processing scheme according to the discharge level of the ground fault to process the fault.
In the ground current state monitoring method applying magnetic resistance sensing, high-precision measurement of the ground wire passing current is achieved by using a tunneling magnetic resistance sensor, the frequency spectrum component and the current value of a sensed current signal are used, abnormal states such as power equipment grounding and the like are evaluated in a digital signal analysis mode, an abnormal evaluation result is obtained by awakening a LoRa wireless data transmission module, information is transmitted to a distribution room or a surrounding intelligent distribution terminal, distribution fault automatic application is supported, distribution equipment fault warning information can also be transmitted to a power grid monitoring center through a distribution Internet of things system, the running states of a transformer, a reactor, a high-voltage bushing and the like in the distribution room/transformer substation are remotely monitored, the ground fault of the power equipment is effectively prevented, and the safe running level of the intelligent unmanned transformer substation is improved.
Preferably, the preset current relationship model includes a three-dimensional rectangular coordinate system established by taking a geometric center selected from the surface of the grounding conductor as an origin, a current relationship model between the X-axis magnetic field component and the grounding conductor to be measured is established by using the X-axis magnetic field strength component in the coordinate system, and the current of the grounding conductor to be measured is calculated by using the established current relationship model.
Further, in a current relation model of the X-axis magnetic field component and the tested grounding conductor, the current of the tested grounding conductor is calculated according to the following formula:
wherein Bx is the magnetic field component in the X-axis direction, the length of the grounding conductor is 2a, L is the width of the busbar, I is the current of the grounding conductor to be measured, d is the vertical distance from the magnetoresistive sensor to the nearest surface of the conductor, b is the diameter of the conductor, (X)1,y1,z1) Representing the coordinate, mu, in a three-dimensional rectangular coordinate system of the magnetoresistive sensor0Is a vacuum magnetic permeability.
In this embodiment, utilize magnetic resistance sensor to carry out signal acquisition, utilize MCU calculation module to handle the signal of gathering, utilize the current relation model of X axle magnetic field component and surveyed earth conductor to restore the signal of gathering into the current signal in the earth conductor, judge whether the transformer is trouble through carrying out the analysis to this current signal, magnetic sensor sensitivity is high, the linearity is good, the dynamic range is big, frequency response is fast and temperature stability is good, only rely on the model calculation can be with the current signal in the earth conductor of signal conversion gathering, need not to set up other sensors, circuit structure is simple, and is light, and it installs in the earth conductor to be convenient for.
The invention also provides a ground current state monitoring device applying magnetic resistance sensing, which is used for implementing the monitoring method and comprises the following steps: the device comprises a magnetoresistive sensor module, an analog signal acquisition module and an MCU (microprogrammed control unit) calculation module;
the power supply system also comprises a self-powered power supply module, wherein the self-powered power supply module is used for supplying electric energy obtained through coupling induction to other modules for power supply, and comprises an induction coil, a magnetic conduction silicon steel sheet, a rectifying circuit and a super capacitor;
the induction coil is wound on the magnetic conductive silicon steel sheet and is used for acquiring a current signal in a coupling induction mode;
the rectifying circuit is used for rectifying the received current signal and then outputting direct current to charge the super capacitor;
the super capacitor is used for releasing the charged electric energy to other modules.
Utilize induction coil coiling on magnetic conduction silicon steel sheet in this embodiment, the induced-current that produces is saved in super capacitor after the rectifier circuit, as the power supply unit of device, and energy-concerving and environment-protective need not additionally to set up active device, simple structure, the implementation of being convenient for.
Further, the magneto-resistive sensor units adopt a high-sensitivity push-pull type electric connection structure and are connected into a push-pull magneto-resistive string and a pull-pull magneto-resistive string along the magnetization direction of the free layer.
The system also comprises a LoRa communication module; the LoRa communication module is awakened according to timing or when the LoRa communication module is judged to be in an abnormal state, runs with low power consumption, and performs information packaging and transmission according to a LoRa wireless communication protocol; and sending the matched processing scheme to an intelligent distribution transformer gateway, transmitting the state information and the abnormal information of the transformer to a distribution monitoring center through the gateway, and remotely monitoring the running state of the power equipment.
Adopt loRa communication module to carry out wireless communication transmission in this embodiment, transmission distance is far away, and the low power dissipation has saved the cost of extra relay, the network deployment of being convenient for.
In any one of the above embodiments, preferably, the sensor further includes a voltage signal conditioning module disposed between the magnetoresistive sensor module and the analog signal acquisition module; and the voltage signal conditioning module is used for filtering and amplifying the sampling signal acquired by the magnetoresistive sensor module.
In this embodiment, a voltage signal conditioning module is used to perform signal preprocessing to filter most of the noise, amplify a weak signal to a voltage amplitude required by a subsequent processor, and output a voltage signal to be detected with an appropriate amplitude by using a preamplifier circuit, a filter circuit and a main amplifier circuit, wherein the voltage signal to be detected is formed after processing to filter most of the noise, which is beneficial to capturing the signal by an analog signal acquisition module and is convenient for the analog signal acquisition module and an MCU calculation module to perform high-precision processing on the acquired signal.
In any one of the above embodiments, preferably, the electromagnetic shielding device further comprises an electromagnetic shielding shell, wherein a specific copper metal layer is formed inside the electromagnetic shielding shell through electrophoretic coating, and the specific copper metal layer is grounded and is used for shielding on-site complex electric field interference signals and high-frequency electromagnetic wave interference signals.
Further, the shield case includes upper and lower portions fixing the ground wire at the center; the magnetic-conductive silicon steel sheets are annularly arranged on the upper portion and the lower portion of the shielding shell, and the magnetic-conductive silicon steel sheets form a closed ring after the upper portion and the lower portion are buckled.
The device housing enclosed in this embodiment is a multi-polymer material with good mechanical properties, thermal stability, and flame retardant properties. The specific copper metal layer is formed inside the shell through electrophoretic coating, grounding is achieved, the electromagnetic shielding layer is achieved, and the functions of field complex electric field interference and high-frequency electromagnetic wave interference are achieved.
An embodiment of another aspect of the present invention further provides a storage medium having a computer program stored thereon, which when executed by a processor, implements the steps of the ground current condition monitoring method applying magnetoresistance sensing as described in any one of the above.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a block diagram of a circuit structure of a ground current state monitoring device using magnetoresistive sensing according to an embodiment of the present disclosure;
fig. 2 is a schematic front-side mounting view of a ground current monitoring device using magnetoresistive sensing according to an embodiment of the present disclosure;
fig. 3 is a schematic installation diagram of a ground current state monitoring device using magnetoresistive sensing according to an embodiment of the present disclosure;
fig. 4 is a flowchart of a method for monitoring a ground current state by applying magnetoresistance sensing according to an embodiment of the present application;
in the figure: 1. the device is provided; 2. an upper portion; 3. a lower portion; 4. a fixed dock; 5. magnetic-conductive silicon steel sheets; 6. an induction coil; 7. a magnetoresistive sensor; 8. and a ground lead.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.
As shown in fig. 1, another aspect of the present application further provides a method for monitoring ground current state by applying magnetoresistance sensing, including the following steps:
s1, quantizing the acquired sampling signals in the grounding wire to obtain real-time waveform data of the sampling signals, wherein the real-time waveform data comprises effective values, peak values and real-time waveforms of fundamental waves and/or harmonic waves of the sampling signals;
s2, calculating a current signal of the grounding conductor according to the real-time waveform data and a preset current relation model;
s3, calculating an effective value of the current signal according to the obtained current signal; the effective values comprise an effective value of a current signal, an effective value of a fundamental wave and effective values of each harmonic wave, and the obtained effective value of the current is compared with a preset current threshold value;
s4, if the current exceeds a preset current threshold and the collected current signal contains a component higher than 2 harmonics, the ground fault is evaluated to be a ground fault with a partial discharge level;
s5, according to a preset processing scheme, the evaluation result is sent to the power distribution equipment to automatically execute corresponding operation, the LoRa wireless communication module is awakened, and information packaging is carried out according to the LoRa wireless communication protocol evaluation result;
and S6, sending the packaged data to an Internet of things gateway, transmitting the data to a power distribution monitoring center through the Internet of things gateway, and remotely monitoring the running state of the power equipment.
In the ground current state monitoring method applying magnetic resistance sensing, high-precision measurement of the ground wire passing current is achieved by using a tunneling magnetic resistance sensor, the frequency spectrum component and the current value of a sensed current signal are used, abnormal states such as power equipment grounding and the like are evaluated in a digital signal analysis mode, an abnormal evaluation result is obtained by awakening a LoRa wireless data transmission module, information is transmitted to a distribution room or a surrounding intelligent distribution terminal, distribution fault automatic application is supported, distribution equipment fault warning information can also be transmitted to a power grid monitoring center through a distribution Internet of things system, the running states of a transformer, a reactor, a high-voltage bushing and the like in the distribution room/transformer substation are remotely monitored, the ground fault of the power equipment is effectively prevented, and the safe running level of the intelligent unmanned transformer substation is improved.
The preset current relation model is a current relation model of an X-axis magnetic field component and a tested grounding conductor constructed by constructing a three-dimensional rectangular coordinate system with a geometric center selected from the surface of the grounding conductor as an origin, and the current of the grounding conductor to be tested is calculated by utilizing the constructed current relation model of the X-axis magnetic field component and the tested grounding conductor.
Calculating the current of the grounding conductor to be measured in a current relation model of the X-axis magnetic field component and the grounding conductor to be measured according to the following formula:
wherein Bx is the magnetic field component in the X-axis direction, the length of the grounding conductor is 2a, L is the width of the busbar, I is the current of the grounding conductor to be measured, d is the vertical distance from the magnetoresistive sensor to the nearest surface of the conductor, b is the diameter of the conductor, (X)1,y1,z1) Representing the coordinate, mu, in a three-dimensional rectangular coordinate system of the magnetoresistive sensor0Is a vacuum magnetic permeability.
In the current relation model of the X-axis magnetic field component and the tested grounding conductor provided by the embodiment, the collected signals are converted into the current signals in the corresponding grounding conductor which can be calculated through the model, whether the transformer fails or not is judged through analyzing the current signals, the magnetic sensor is high in sensitivity, good in linearity, large in dynamic range, fast in frequency response and good in temperature stability, the collected signals can be converted into the current signals in the grounding conductor only by means of model calculation, and other sensors are not required to be arranged.
As shown in fig. 4, an embodiment of an aspect of the present invention provides a ground current condition monitoring device using magnetoresistive sensing, which is disposed on a ground lead, and is used for implementing the above method, and the device includes: the device comprises a magnetoresistive sensor module, an analog signal acquisition module, an MCU (microprogrammed control unit) calculation module, a LoRa communication module and a self-powered power supply module; the installation position of the device is shown in fig. 3 as the device 1.
The self-powered power supply module obtains electric energy in a magnetic field coupling mode through induction and provides the obtained electric energy for other modules to supply power; the self-powered power supply module comprises an induction coil 6, a rectifying circuit and a super capacitor; the induction coil 6 is wound on the magnetic conductive silicon steel sheet 7, and a current signal is obtained in a coupling induction mode; outputting the obtained current signal to a rectifying circuit; the rectifying circuit is used for rectifying the received current signal and then outputting direct current to charge the super capacitor; and the super capacitor is used for releasing the charged electric energy to other modules for power supply.
Utilize induction coil coiling on magnetic conduction silicon steel sheet in this embodiment, the induced-current that produces is saved in super capacitor after the rectifier circuit, as the power supply unit of device, and energy-concerving and environment-protective need not additionally to set up active device, simple structure, the implementation of being convenient for.
The magnetic resistance sensor module is used for acquiring a sampling signal in a grounding wire; sending the acquired sampling signal to an analog signal acquisition module; the magnetoresistive sensor module is a tunneling magnetoresistive sensor, and the technical indexes of the sensor are as follows: load resistance is more than or equal to 1 Komega, error is +/-1%, linearity is 0.5%, response time is 5 mu s, and temperature drift is +/-0.5 Mv/DEG C. The acquisition parameter refers to a measurement range of the calibration from 0.1mA to 10A, the frequency measurement range is from direct current to 1MHz, and the frequency completely covers the multipoint earth fault current frequency of the main transformer. The magnetic sensor has high sensitivity, good linearity, large dynamic range, fast frequency response and good temperature stability.
The configuration method is that the pre-amplification circuit, the filter circuit and the main amplification circuit output voltage signals to be detected with proper amplitude and most of noise filtered out after processing.
The analog signal acquisition module is used for carrying out quantization processing on the received sampling signals to obtain real-time waveform data and sending the real-time waveform data to the MCU calculation module, wherein the real-time waveform data comprises effective values, peak values and real-time waveforms of fundamental waves and/or harmonic waves of the sampling signals; the analog signal sampling module is used for carrying out quantization processing on the analog signals, obtaining effective values and peak values of fundamental waves and/or harmonic waves in the sampled voltage signals and obtaining real-time waveform data. The use of a multi-channel parallel 12-bit ADC can process fine signals to improve computational accuracy. The device is beneficial to the analog signal acquisition module to capture signals, and is convenient for the analog signal acquisition module and the MCU calculation module to carry out high-precision processing on the acquired signals.
The MCU calculation module comprises a signal calculation unit, a comparison unit and a transmission unit;
the signal calculation unit is used for calculating a current signal of the grounding wire according to the real-time waveform data and a preset current relation model;
the comparison unit calculates the effective value of the current signal according to the obtained current signal; the effective values comprise an effective value of a current signal, an effective value of a fundamental wave and effective values of each harmonic wave, and the obtained effective value of the current is compared with a preset current threshold value; if the current exceeds a preset current threshold and the collected current signal contains components higher than 2 harmonics, the ground fault is evaluated to be a ground fault with a partial discharge level;
the transmission unit is used for sending the evaluation result to the power distribution equipment to automatically execute corresponding operation according to a preset processing scheme, waking up the LoRa wireless communication module at regular time or when an abnormal condition is detected, and packaging the evaluation result according to the LoRa wireless communication protocol;
further, the discharge level may be set according to the harmonic component, and the treatment plan may be set for the fault according to the discharge level. For example, a component including a harmonic higher than the order 2 is determined as a ground fault at the partial discharge level; according to a preset processing scheme, the evaluation result is sent to the power distribution equipment to automatically execute corresponding operation, an LoRa wireless communication module is awakened, and the evaluation result and information are packaged according to an LoRa wireless communication protocol; the LoRa communication unit sends the data that pack well to the thing through the wireless communication module of LoRa and allies oneself with the gateway, transmits to distribution monitoring center, remote monitoring power equipment's running state through the thing allies oneself with the gateway. Adopt loRa communication module to carry out wireless communication transmission, transmission distance is far away, and the low power dissipation has saved the cost of extra relay, the network deployment of being convenient for.
The MCU computing module is simultaneously provided with basic units such as a memory, a FLASH and the like, so that the computing operation of the system is guaranteed. And a Micro Control Unit (MCU) adopts a Cortex-M kernel, and the highest frequency can reach 72 MHz. STM series from ST corporation such as STM32F103C8, Micro Control Unit (MCU), with Cortex-M core, can be used with maximum frequency up to 72 MHz. The LoRa communication unit packs current signal information and abnormal state evaluation results according to a LoRa wireless communication protocol, wakes up the LoRa wireless communication module regularly or in an abnormal state to carry out remote data transmission, and timely sends the grounding state of the power equipment to a remote monitoring center.
In the ground current state monitoring device applying magnetic resistance sensing, the high-precision measurement of the through current of the ground wire is realized by utilizing a tunneling magnetic resistance sensor, the frequency spectrum component of the sensed current signal is utilized, the current value is utilized, the abnormal states such as the grounding of the power equipment and the like are evaluated in a digital signal analysis mode, the abnormal evaluation result is transmitted to a distribution room or a surrounding intelligent distribution terminal through awakening a LoRa wireless data transmission module, the automatic application of distribution faults is supported, the fault warning information of the power distribution equipment can also be transmitted to a power grid monitoring center through a distribution Internet of things system, the running states of a transformer, a reactor, a high-voltage bushing and the like in the distribution room/transformer substation are remotely monitored, the grounding faults of the power equipment are effectively prevented, and the safe running level of the intelligent unmanned transformer substation is.
As shown in fig. 2, the magnetic sensor further comprises a shielding shell, wherein the magnetic sensor 7 module, the analog signal acquisition module, the MCU calculation module, the LoRa communication module and the self-powered power supply module are arranged in the shielding shell; are both arranged in a shielded housing comprising an upper part 2 and a lower part 3, which fix a ground conductor 8 in the centre; the magnetic-conducting silicon steel sheets 5 are annularly arranged on the upper portion 2 and the lower portion 3 of the shielding shell, and the magnetic-conducting silicon steel sheets 5 form a closed ring after the upper portion 2 and the lower portion 3 are buckled.
The device housing enclosed in this embodiment is a multi-polymer material with good mechanical properties, thermal stability, and flame retardant properties. The specific copper metal layer is formed inside the shell through electrophoretic coating, grounding is achieved, the electromagnetic shielding layer is achieved, and the functions of field complex electric field interference and high-frequency electromagnetic wave interference are achieved.
The position relationship between the magnetoresistive sensor and the ground conductor is shown in fig. 2. The magneto resistive sensor unit adopts high sensitivity's push-pull electricity connection structure, connects into along the free layer magnetization direction and pushes away magneto resistive string and draw magneto resistive string to set up in the neighbour's position of awaiting measuring earth conductor, push away magneto resistive sensing unit cluster and draw magneto resistive sensing unit cluster electricity and connect into push-pull magneto resistive sensor, magneto resistive sensor adopts micro-processing technology to make in batches, and the cost is extremely low, and economic nature is splendid.
The preset current relation model is used for constructing a three-dimensional rectangular coordinate system by taking a geometric center selected from the surface of the grounding conductor as an origin, wherein the current direction of the grounding conductor is a Z axis, the tangential direction perpendicular to the conductor is a Y axis, the tangential direction is an X axis, and the current relation model of the X-axis magnetic field component and the grounding conductor to be measured is constructed by the magnetic field intensity component Bx in the X-axis direction in the three-dimensional rectangular coordinate system.
Calculating the current of the grounding conductor to be measured in a current relation model of the X-axis magnetic field component and the grounding conductor to be measured according to the following formula:
wherein Bx is the magnetic field component in the X-axis direction, the length of the grounding conductor is 2a, L is the width of the busbar, I is the current of the grounding conductor to be measured, d is the vertical distance from the magnetoresistive sensor to the nearest surface of the conductor, b is the diameter of the conductor, (X)1,y1,z1) Representing the coordinate, mu, in a three-dimensional rectangular coordinate system of the magnetoresistive sensor0Is a vacuum magnetic permeability.
After Bx is obtained, the formula is input to calculate the current of the grounding conductor, the abnormal state diagnosis function based on current signal analysis is realized in the MCU, and the specific calculation and analysis process is as follows:
(1) and after receiving the sampling voltage signal, the MCU extracts an effective value and a peak value of a fundamental wave and/or a harmonic wave, obtains real-time waveform data, and then calculates a current signal of the grounding wire by applying formula 1.
(2) And performing FFT (fast Fourier transform) and frequency domain analysis on the current signal to respectively obtain effective values (including the effective value of the signal, the effective value of the fundamental wave and the effective value of each harmonic) of the current signal.
(3) And comparing the effective value and the peak value of the current signal with a preset current threshold, and if the grounding current value of the electrical equipment exceeds the preset current threshold and the acquired current signal contains components higher than 2 harmonics, evaluating that the grounding fault of the partial discharge level occurs.
In this embodiment, utilize magnetic resistance sensor to carry out signal acquisition, utilize MCU calculation module to handle the signal of gathering, utilize the current relation model of X axle magnetic field component and surveyed earth conductor to restore the signal of gathering into the current signal in the earth conductor, judge whether the transformer is trouble through carrying out the analysis to this current signal, magnetic sensor sensitivity is high, the linearity is good, the dynamic range is big, frequency response is fast and temperature stability is good, can change the current signal in the earth conductor with the signal of gathering by model calculation, need not to set up other sensors, circuit structure is simple, and is light, be convenient for install in the earth conductor.
An embodiment of another aspect of the present invention further provides a storage medium having a computer program stored thereon, which when executed by a processor, implements the steps of the ground current condition monitoring method applying magnetoresistance sensing as described in any one of the above.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be appreciated by those skilled in the art that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.
Claims (10)
1. A ground current state monitoring method applying magneto-resistance sensing is characterized by comprising the following steps:
quantizing the acquired sampling signals in the grounding wire to obtain real-time waveform data of the sampling signals, wherein the real-time waveform data comprises effective values, peak values and real-time waveforms of fundamental waves and/or harmonic waves of the sampling signals;
calculating a current signal of the grounding conductor according to the real-time waveform data and a preset current relation model;
calculating an effective value of the current signal according to the obtained current signal; the effective values comprise an effective value of a current signal, an effective value of a fundamental wave and effective values of each harmonic wave, and the obtained effective value of the current is compared with a preset current threshold value;
if the current exceeds a preset current threshold and the collected current signal contains components higher than 2 harmonics, the ground fault is evaluated to be a ground fault with a partial discharge level;
and matching a preset processing scheme according to the discharge level of the ground fault to process the fault.
2. The method according to claim 1, wherein the predetermined current relationship model comprises a three-dimensional rectangular coordinate system constructed by using a geometric center selected from the surface of the ground lead as an origin, a current relationship model constructed by using an X-axis magnetic field strength component of the coordinate system, which is tangential to a plane perpendicular to the lead, to construct an X-axis magnetic field component and a current relationship model of the ground lead to be measured, and a current of the ground lead to be measured is calculated by using the constructed current relationship model.
3. The method for monitoring the state of the ground current by applying magnetoresistive sensing according to claim 2, wherein the current of the ground wire to be measured is calculated in a model of the relationship between the X-axis magnetic field component and the current of the ground wire to be measured according to the following formula:
wherein Bx is the magnetic field component in the X-axis direction, the length of the grounding conductor is 2a, L is the width of the busbar, I is the current of the grounding conductor to be measured, d is the vertical distance from the magnetoresistive sensor to the nearest surface of the conductor, b is the diameter of the conductor, (X)1,y1,z1) Representing the coordinate, mu, in a three-dimensional rectangular coordinate system of the magnetoresistive sensor0Is a vacuum magnetic permeability.
4. A ground current condition monitoring device using magnetoresistive sensing for implementing the monitoring method of any one of the preceding claims 1-3, comprising: the device comprises a magnetoresistive sensor module, an analog signal acquisition module and an MCU (microprogrammed control unit) calculation module; it is characterized in that the preparation method is characterized in that,
the power supply system also comprises a self-powered power supply module, wherein the self-powered power supply module is used for supplying electric energy obtained through coupling induction to other modules for power supply, and comprises an induction coil, a magnetic conduction silicon steel sheet, a rectifying circuit and a super capacitor;
the induction coil is wound on the magnetic conductive silicon steel sheet and is used for acquiring a current signal in a coupling induction mode;
the rectifying circuit is used for rectifying the received current signal and then outputting direct current to charge the super capacitor;
the super capacitor is used for releasing the charged electric energy to other modules.
5. The ground current state monitoring device applying magnetic resistance sensing according to claim 4, wherein the magnetic resistance sensor unit adopts a high-sensitivity push-pull type electric connection structure, and is connected into a push-pull magnetic resistance string and a pull-pull magnetic resistance string along the magnetization direction of the free layer.
6. The ground current state monitoring device applying magnetoresistive sensing according to claim 4, further comprising a LoRa communication module; the LoRa communication module is awakened according to timing or when the LoRa communication module is judged to be in an abnormal state, runs with low power consumption, and performs information packaging and transmission according to a LoRa wireless communication protocol; and sending the matched processing scheme to an intelligent distribution transformer gateway, transmitting the state information and the abnormal information of the transformer to a distribution monitoring center through the gateway, and remotely monitoring the running state of the power equipment.
7. The ground current state monitoring device applying magnetoresistive sensing according to claim 4, further comprising a voltage signal conditioning module; and the voltage signal conditioning module is used for filtering and amplifying the sampling signal acquired by the magnetoresistive sensor module.
8. The ground current state monitoring device applying magnetoresistance sensing according to claim 4, further comprising an electromagnetic shielding case, wherein a specific copper metal layer is formed inside the electromagnetic shielding case by electrophoretic coating, and the specific copper metal layer is grounded for shielding on-site complex electric field interference signals and high-frequency electromagnetic wave interference signals.
9. The ground current condition monitoring device applying magnetoresistive sensing according to claim 8, wherein the shielding housing includes upper and lower portions to secure the ground conductor in the center; the magnetic-conductive silicon steel sheets are annularly arranged on the upper portion and the lower portion of the shielding shell, and the magnetic-conductive silicon steel sheets form a closed ring after the upper portion and the lower portion are buckled.
10. A storage medium, characterized in that the storage medium has stored thereon a computer program which, when executed, implements the steps of the ground current condition monitoring method applying magnetoresistive sensing according to any of claims 1 to 3.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202522618U (en) * | 2012-04-10 | 2012-11-07 | 重庆市电力公司长寿供电局 | Device for carrying out online monitoring on grounding of transformer core |
| CN104052162A (en) * | 2013-03-14 | 2014-09-17 | 王铮 | Intelligent self-powered device with real-time fault detection |
| CN107449954A (en) * | 2016-06-01 | 2017-12-08 | 李朝晖 | Power transformer iron core earth current holography on-Line Monitor Device and method |
| 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 |
| JP2018054398A (en) * | 2016-09-28 | 2018-04-05 | 中日本ハイウェイ・エンジニアリング名古屋株式会社 | Ground fault current detector |
| CN109272257A (en) * | 2018-11-02 | 2019-01-25 | 国网山西省电力公司电力科学研究院 | A kind of electric cable stoppage appraisal procedure and system based on higher hamonic wave database |
| CN109444528A (en) * | 2018-11-05 | 2019-03-08 | 北京许继电气有限公司 | A kind of Transformer Condition Monitoring System and method based on iron core grounding current |
-
2021
- 2021-01-04 CN CN202110004870.6A patent/CN112834811A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202522618U (en) * | 2012-04-10 | 2012-11-07 | 重庆市电力公司长寿供电局 | Device for carrying out online monitoring on grounding of transformer core |
| CN104052162A (en) * | 2013-03-14 | 2014-09-17 | 王铮 | Intelligent self-powered device with real-time fault detection |
| CN107449954A (en) * | 2016-06-01 | 2017-12-08 | 李朝晖 | Power transformer iron core earth current holography on-Line Monitor Device and method |
| JP2018054398A (en) * | 2016-09-28 | 2018-04-05 | 中日本ハイウェイ・エンジニアリング名古屋株式会社 | Ground fault current detector |
| 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 |
| CN109272257A (en) * | 2018-11-02 | 2019-01-25 | 国网山西省电力公司电力科学研究院 | A kind of electric cable stoppage appraisal procedure and system based on higher hamonic wave database |
| CN109444528A (en) * | 2018-11-05 | 2019-03-08 | 北京许继电气有限公司 | A kind of Transformer Condition Monitoring System and method based on iron core grounding current |
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Application publication date: 20210525 |