Mutual inductor secondary circuit impedance on-line monitoring system and method

Abstract

The invention discloses a mutual inductor secondary circuit impedance on-line monitoring system, which can sense alternating current from a mutual inductor secondary circuit by utilizing an energy taking coil, and can realize charging and energy taking of a super capacitor by rectifying the voltage of a secondary terminal of the coil. The super capacitor can discharge the electronic circuit through switch control so as to supply power for signal sampling and the electronic circuit, current and voltage measurement of a secondary circuit of the mutual inductor is realized through the secondary measurement part, and real-time calculation of impedance of the secondary circuit of the mutual inductor and external information transmission are realized through the communication part and the MCU together.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alternating current test, in particular to a kind of on-line monitoring system for impedance of secondary circuit of mutual inductor. BACKGROUND

[0002] When low-voltage current transformer is in normal operation, the secondary circuit load is composed of wire, terminal contact resistance and instruments and terminals threaded and connected in the wire. The secondary circuit load of low-voltage current transformer is in the order of milliohm, and its value directly affects the error of low-voltage current transformer. When the secondary terminal of current transformer is virtual or corroded, the contact resistance will rise to hundreds of milliohms or even ohms. The increase of secondary circuit load will directly lead to the deterioration of the measurement performance of low-voltage current transformer, and may cause heating at the secondary wiring terminal, which is not conducive to the normal and stable operation of the equipment. SUMMARY

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides an on-line monitoring system and method for impedance of secondary circuit of mutual inductor, which can realize real-time monitoring and fault diagnosis of the state of secondary circuit by introducing adaptive energy harvesting and dynamic signal analysis technology in the secondary circuit of mutual inductor, while reducing the dependence on external power supply.

[0004] The on-line monitoring system for impedance of secondary circuit of mutual inductor according to the first aspect of the present application is characterized in that it comprises:

[0005] The energy capture module adopts a closed magnetic ring structure, is nested outside the secondary wire of the mutual inductor, and obtains the transient magnetic field energy in the secondary circuit through electromagnetic induction principle. The energy storage module is composed of a plurality of parallel micro thin film capacitors, is connected with the energy capture module through a rectifier circuit, and is used for converting the captured energy into stable DC voltage. The signal acquisition module includes a high-sensitivity Hall effect sensor and a set of low-impedance voltage dividing resistors, which are used to detect the current intensity and terminal voltage value in the secondary circuit respectively. The data processing module integrates a high-performance microcontroller, receives the data transmitted by the signal acquisition module through an analog-to-digital conversion interface, and calculates the equivalent impedance value of the secondary circuit based on a preset algorithm. The communication interface module is designed with a wireless radio frequency chip, supports standard communication protocols, and is used for transmitting monitoring data outward.

[0006] The transformer secondary circuit impedance online monitoring system according to the embodiment of the present application has at least the following beneficial effects: the present application provides a system capable of monitoring the transformer secondary circuit in real time, solves the problem of dependence on external power supply of the traditional monitoring device by introducing the energy capturing module and the energy storage module, and realizes accurate acquisition of the current and voltage signals by using the Hall effect sensor and the low-impedance voltage dividing resistor, thereby improving the monitoring precision.

[0007] According to some embodiments of the present application, the system further comprises:

[0008] The display module is arranged on the surface of the device shell, adopts a low-power liquid crystal display screen, and is connected to the data processing module through a flexible circuit board, and is used for intuitively displaying the monitoring parameters and alarm information.

[0009] The energy storage module is used for providing continuous power supply for the display module, and ensures that the display module can still work normally under low light conditions.

[0010] According to some embodiments of the present application, the system further comprises:

[0011] The data recording module is composed of a non-volatile storage chip, is connected to the data processing module through a serial peripheral interface, and is used for saving the running state and historical data of the monitoring system within a certain time range.

[0012] The data recording module and the data processing module work cooperatively, automatically trigger the data backup function when an abnormal event is monitored, and upload the related information to the cloud server through the communication interface module.

[0013] According to some embodiments of the present application, the closed magnetic ring structure of the energy capturing module is made of nanocrystalline material with high magnetic permeability, and the inner diameter size of the closed magnetic ring structure matches the outer diameter of the transformer secondary conductor.

[0014] The transformer secondary circuit impedance online monitoring method according to the second embodiment of the present application applies any one of the transformer secondary circuit impedance online monitoring systems, and the method comprises the following steps:

[0015] The alternating current voltage signal is obtained through the closed magnetic ring structure nested outside the transformer secondary conductor;

[0016] The alternating current voltage signal is converted into direct current voltage through the rectifier circuit and stored in the energy storage module;

[0017] The current intensity in the transformer secondary circuit is detected by using the Hall effect sensor, and the terminal voltage value is obtained through the low-impedance voltage dividing resistor.

[0018] The collected current and voltage signals are transmitted to a data processing module for analog-to-digital conversion and numerical analysis, and the equivalent impedance value of the secondary circuit is calculated;

[0019] The monitoring data is transmitted to the outside through the communication interface module in a standard communication protocol.

[0020] According to some embodiments of the present application, the method further comprises:

[0021] The monitoring parameters and alarm information are displayed through a low-power liquid crystal display screen; wherein the liquid crystal display screen is powered by an energy storage module and connected to the data processing module through a flexible circuit board.

[0022] According to some embodiments of the present application, the closed magnetic ring structure is made of nanocrystalline material with high magnetic permeability, the inner diameter size of which matches the outer diameter of the secondary conductor of the transformer, and the rectifier circuit adopts a full-bridge rectification architecture built by Schottky diodes and smoothes the output waveform through a filter capacitor

[0023] According to some embodiments of the present application, the communication interface module is a low-power Bluetooth protocol, the antenna part of which adopts a planar inverted F type design and is connected to the data processing module through a serial communication interface, and the system integrates a signal strength detection function to adjust the transmission power or switch the communication frequency according to the signal quality.

[0024] Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and / or by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0026] Figure 1 The structure block diagram of the transformer secondary circuit impedance online monitoring system of the embodiments of the present application is shown in the figure;

[0027] Figure 2 The principle schematic diagram of the energy capture module of the transformer secondary circuit impedance online monitoring system is shown in the figure. Figure 1 The principle schematic diagram of the energy capture module of the transformer secondary circuit impedance online monitoring system is shown in the figure. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0029] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by the upper, lower, front, rear, left, right and the like, is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0030] In the description of the present application, the meaning of one or more is one or more, the meaning of multiple is two or more, greater than, less than, more than and the like are understood as not including the number, above, below, within and the like are understood as including the number. If the first, second is described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0031] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0032] Reference Figure 1 The embodiment of the present application provides a kind of mutual inductor secondary circuit impedance on-line monitoring system, at least includes:

[0033] Energy capture module adopts closed magnetic ring structure, is nested in mutual inductor secondary wire outside, and obtains the transient magnetic field energy in secondary circuit by electromagnetic induction principle;

[0034] Energy storage module is composed of multiple parallel micro thin film capacitors, is connected with energy capture module by rectifier circuit, and is used to convert the energy captured into stable DC voltage;

[0035] Signal acquisition module contains a high-sensitivity Hall effect sensor and a set of low-impedance voltage dividing resistors, which are used to detect the current intensity and terminal voltage value in secondary circuit respectively;

[0036] Data processing module integrates a high-performance microcontroller, receives the data transmitted by signal acquisition module through analog-digital conversion interface, and calculates the equivalent impedance value of secondary circuit based on preset algorithm;

[0037] Communication interface module is designed with wireless radio frequency chip, supports standard communication protocol, and is used to transmit monitoring data outward.

[0038] Preferably, the system further comprises:

[0039] A display module is arranged on the surface of the device shell, adopts a low-power liquid crystal display, and is connected with the data processing module through a flexible circuit board, and is used for intuitively displaying monitoring parameters and alarm information.

[0040] An energy storage module is used for providing continuous power supply for the display module, and ensures that the display module can still work normally under low light conditions.

[0041] A data recording module is composed of a non-volatile storage chip, is connected with the data processing module through a serial peripheral interface, and is used for saving the running state and historical data of the monitoring system within a certain time range. The data recording module cooperates with the data processing module to automatically trigger a data backup function when an abnormal event is monitored, and uploads relevant information to a cloud server through a communication interface module.

[0042] Further, in order to improve the stability and reliability of the system, the closed magnetic ring structure of the energy capture module is made of nanocrystalline material with high magnetic permeability, the inner diameter size of which matches the outer diameter of the secondary conductor of the transformer, so as to minimize the gap between the magnetic ring and the conductor, thereby improving the energy capture efficiency. The rectifier circuit adopts a full-bridge rectification architecture built by Schottky diodes to convert the captured alternating voltage into direct current voltage, and simultaneously smoothes the output waveform through a filter capacitor to reduce the influence of voltage fluctuation on the subsequent circuit.

[0043] Specifically, the principle of inductive energy capture of the energy capture module is as shown in Figure 2 , wherein the switch K1 controls whether the energy capture coil is powered by the super capacitor, and the switch K2 controls whether the super capacitor is powered by the external circuit.

[0044] The Hall effect sensor in the signal acquisition module is installed near the secondary conductor and connected with the device shell through a fixed support, the sensitive axis direction of which is consistent with the magnetic field direction of the conductor to maximize the magnetic field induction strength. The low-impedance voltage dividing resistor is directly welded on the printed circuit board and is connected in series with the output end of the Hall effect sensor to form a complete signal conditioning circuit. The circuit adjusts the original signal to an amplitude range suitable for analog-to-digital conversion through scaling and noise suppression processing.

[0045] The microcontroller of the data processing module has a built-in floating point operation unit and can quickly perform complex mathematical operations. The internal memory is divided into a program storage area and a data buffer area, the program storage area is used to store monitoring algorithms and control logic, and the data buffer area is used to temporarily store real-time collected signal data. The microcontroller triggers the signal acquisition operation through a timing interrupt mechanism, and sequentially sends the collected data to the analog-to-digital converter for digital processing. When calculating the equivalent impedance value, the microcontroller calls a preset numerical analysis algorithm, combines the sampling values of the current and voltage, and deduces the impedance characteristic curve of the secondary circuit.

[0046] The wireless radio frequency chip of the communication interface module selects a low-power Bluetooth protocol, and the antenna part thereof adopts a planar inverted F type design and is printed on one side of a printed circuit board to reduce the occupied space. The chip is connected with the microcontroller through a serial communication interface, regularly reads the monitoring data and packs them into a standard data frame format, and sends them to a remote terminal through a wireless channel. In order to enhance the communication stability, the system also integrates a signal strength detection function, and when the signal quality is detected to decrease, the transmission power is automatically adjusted or the communication frequency is switched.

[0047] The liquid crystal display screen of the display module adopts a segment code driving mode, and only the part of the pixel points that need to be displayed is activated, so as to reduce the power consumption. The flexible circuit board is connected with the data processing module through a hot-press welding process, so that the electrical contact is good and the mechanical strength is reliable. The refresh frequency of the display module is controlled by the microcontroller, and when the monitoring parameter changes, the display screen will immediately update the display content, and will flash when an abnormality occurs.

[0048] The non-volatile storage chip of the data recording module adopts a serial flash memory technology, has high write durability and low power consumption characteristics. The storage capacity can be expanded according to actual needs, and usually can save not less than one month of historical data. The data processing module stores the monitoring data into the chip through periodic write operation, and at the same time, when an abnormal event occurs, triggers the instant backup function, marks the event related data as high priority and stores it separately.

[0049] In summary, the present application introduces an energy capture module, a signal acquisition module, a data processing module, a communication interface module, a display module and a data recording module, and constructs a complete transformer secondary circuit monitoring system. The modules work cooperatively through clear connection relationship and optimized technical means, not only solve the problem of dependence on external power supply of traditional monitoring equipment, but also significantly improve the monitoring accuracy and the reliability of data transmission, and provide a strong guarantee for the stable operation of the transformer secondary circuit.

[0050] Without affecting the measurement accuracy of the original measurement device, the energy taking coil is coupled in the original measurement secondary circuit, and the voltage of the coil secondary terminal is rectified to charge the super capacitor and supply power to the electronic circuit in the intelligent end cover.

[0051] Embodiment two

[0052] According to the transformer secondary circuit monitoring system provided in the above embodiment one, real-time monitoring and fault diagnosis of the state of the transformer secondary circuit can be realized through the cooperative work of multiple modules. Another embodiment of the present application provides an operation method based on the monitoring system provided in the above embodiment.

[0053] Firstly, the energy capture module 1 is deployed by embedding a closed magnetic ring outside the secondary conductor of the transformer. The closed magnetic ring is made of nanocrystalline material with high magnetic permeability, and its inner diameter matches the outer diameter of the secondary conductor of the transformer, ensuring that the gap between the magnetic ring and the conductor is minimized. When there is current flowing in the secondary circuit of the transformer, the closed magnetic ring induces transient magnetic field energy and converts it into an alternating voltage signal. This alternating voltage signal is processed through a rectifier circuit, where a full-bridge rectifier architecture is built with Schottky diodes to convert the alternating voltage into a direct current voltage, and a filter capacitor smooths the output waveform to reduce voltage fluctuations and their impact on subsequent circuits. The direct current voltage after rectification and filtering is transmitted to the energy storage module, which is composed of multiple parallel micro-thin film capacitors, which can stabilize the captured energy to power the entire system. This process enables the continuous operation of the monitoring system without external power supply, solving the problem of dependence on external power supply for traditional devices.

[0054] Subsequently, the signal acquisition module begins to work, and the Hall effect sensor is installed near the secondary conductor, with its sensitive axis direction consistent with the direction of the conductor magnetic field to maximize the magnetic field induction strength. The Hall effect sensor detects the current intensity in the secondary circuit and transmits the raw signal to a low-impedance voltage dividing resistor for proportional scaling and noise suppression processing. The low-impedance voltage dividing resistor is directly soldered on the printed circuit board and is connected in series with the output of the Hall effect sensor to form a complete signal conditioning circuit, which adjusts the raw signal to an amplitude range suitable for analog-to-digital conversion. The conditioned signal is transmitted to the data processing module through the signal transmission path. The microcontroller has a built-in floating point operation unit that can quickly perform complex mathematical operations, and its timing interrupt mechanism triggers the signal acquisition operation and sends the collected data to the analog-to-digital converter for digital processing in sequence. When calculating the equivalent impedance value, the microcontroller calls the preset numerical analysis algorithm and deduces the impedance characteristic curve of the secondary circuit based on the sampling values of current and voltage. This process enables accurate monitoring of the state of the secondary circuit, significantly improving monitoring accuracy.

[0055] The communication interface module realizes data transmission function through wireless radio frequency chip design. The wireless radio frequency chip uses low-power Bluetooth protocol, and the antenna part adopts planar inverted F type design, which is printed on one side of the printed circuit board to reduce the occupied space. The wireless radio frequency chip is connected with the microcontroller through serial communication interface, reads the monitoring data regularly and packs them into standard data frame format, and sends them to the remote terminal through wireless channel. To enhance communication stability, the system integrates signal strength detection function, which automatically adjusts transmission power or switches communication frequency when detecting signal quality decline. This design ensures that monitoring data can be uploaded to the remote monitoring platform in real time, making it convenient for operation and maintenance personnel to timely grasp the equipment operation status.

[0056] The display module is connected with the data processing module through a flexible circuit board, and the flexible circuit board ensures good electrical contact and reliable mechanical strength through a hot-press welding process. The liquid crystal display screen adopts a segment code driving mode, and only the pixel points that need to be displayed are activated to reduce power consumption. The refresh frequency of the display module is controlled by the microcontroller, and when the monitoring parameters change, the display screen will immediately update the display content, and will flash to prompt when an abnormality occurs. The energy storage module provides continuous power supply for the display module to ensure that it can still work normally under low light conditions. This design enables on-site personnel to intuitively understand the changes in monitoring parameters and take timely measures in abnormal situations.

[0057] The data recording module is composed of a non-volatile storage chip and is connected with the data processing module through a serial peripheral interface. The non-volatile storage chip adopts a serial flash memory technology, has high write durability and low power consumption characteristics, and its storage capacity can be expanded according to actual needs, and it can usually save historical data for not less than one month. The data processing module 3 stores the monitoring data in the chip through periodic write operations, and at the same time triggers the instant backup function when an abnormal event occurs, marks the event-related data as high priority and stores it separately. This design not only ensures the integrity of historical data, but also provides a reliable basis for tracing abnormal events.

[0058] In summary, in the above application scenarios, the modules work together to realize real-time monitoring and fault diagnosis of the secondary circuit state of the mutual inductor. From energy capture to signal acquisition, data processing, communication transmission, and data display and recording, each link ensures the stability and reliability of system operation through clear technical means and optimized design schemes. Through the above steps, the present application not only solves the problem of dependence on external power supply of traditional monitoring equipment, but also significantly improves the monitoring accuracy and reliability of data transmission, providing effective protection for the safe operation of the secondary circuit of the mutual inductor.

[0059] The device embodiments described above are only illustrative, and units described as separate components can or can not be physically separated, i.e. can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment scheme.

[0060] As will be appreciated by one of ordinary skill in the art, all or some of the steps, systems, etc. in the methods disclosed above can be embodied in software, firmware, hardware, and / or suitable combinations thereof. Some or all of the physical components can be implemented with software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or can be implemented as hardware, or as an integrated circuit, such as an application- specific integrated circuit. Such software can be distributed on computer readable media, which can comprise computer storage media (or non-transitory media), and communication media (or transitory media). As is well known to those of ordinary skill in the art, the term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media include, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Further, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media.

[0061] The above description is that of the preferred embodiments of the present application. Various equivalents substitutions of the techniques described herein can be implemented, both currently known or later developed, without departing from the spirit and scope of the application. Such equivalents substitutions are also intended to be encompassed by the claims of the present application.

Claims

1. An online monitoring system for the secondary circuit impedance of a current transformer, characterized in that, include: The energy capture module adopts a closed magnetic ring structure, which is nested outside the secondary conductor of the current transformer, and obtains transient magnetic field energy in the secondary circuit through the principle of electromagnetic induction. The energy storage module consists of multiple parallel-connected miniature thin-film capacitors and is connected to the energy capture module through a rectifier circuit to convert the captured energy into a stable DC voltage. The signal acquisition module includes a high-sensitivity Hall effect sensor and a set of low-impedance voltage divider resistors, which are used to detect the current intensity and terminal voltage value in the secondary circuit, respectively. The data processing module integrates a high-performance microcontroller, which receives data transmitted from the signal acquisition module through an analog-to-digital converter interface and calculates the equivalent impedance value of the secondary circuit based on a preset algorithm. The communication interface module adopts a wireless radio frequency chip design, supports standard communication protocols, and is used to transmit monitoring data to external systems.

2. The online monitoring system for the secondary circuit impedance of a current transformer according to claim 1, characterized in that, The system also includes: The display module is located on the surface of the device housing. It uses a low-power LCD screen and is connected to the data processing module via a flexible circuit board. It is used to intuitively display monitoring parameters and alarm information. The energy storage module provides continuous power to the display module, ensuring its normal operation even in low-light conditions.

3. The system according to claim 1, characterized in that, The system also includes: The data recording module consists of a non-volatile memory chip and is connected to the data processing module through a serial peripheral interface. It is used to save the operating status and historical data of the monitoring system within a certain time range. The data recording module works in conjunction with the data processing module. When an abnormal event is detected, the data backup function is automatically triggered, and the relevant information is uploaded to the cloud server through the communication interface module.

4. The system according to claim 1, characterized in that, The closed magnetic ring structure of the energy harvesting module is made of nanocrystalline material with high magnetic permeability, and its inner diameter is matched with the outer diameter of the secondary conductor of the transformer.

5. A method for online monitoring of the secondary circuit impedance of a current transformer, employing the online monitoring system for the secondary circuit impedance of a current transformer described in any one of claims 1 to 4, characterized in that, Includes the following steps: AC voltage signals are obtained through a closed magnetic ring structure nested outside the secondary conductors of the current transformer; The AC voltage signal is converted into DC voltage through a rectifier circuit and stored in the energy storage module; The current intensity in the secondary circuit of the current transformer is detected by a Hall effect sensor, and the terminal voltage value is obtained by a low-impedance voltage divider resistor. The acquired current and voltage signals are transmitted to the data processing module for analog-to-digital conversion and numerical analysis to calculate the equivalent impedance value of the secondary circuit. The monitoring data is transmitted externally using a standard communication protocol via the communication interface module.

6. The method according to claim 5, characterized in that, The method further includes: Monitoring parameters and alarm information are displayed on a low-power LCD screen; the LCD screen is powered by an energy storage module and connected to a data processing module via a flexible circuit board.

7. The method according to claim 5, characterized in that, The closed magnetic ring structure is made of nanocrystalline material with high magnetic permeability. Its inner diameter is matched with the outer diameter of the secondary conductor of the current transformer. The rectifier circuit uses Schottky diodes to build a full-bridge rectifier architecture and uses a filter capacitor to smooth the output waveform.

8. The method according to claim 5, characterized in that, The communication interface module uses the Bluetooth Low Energy protocol. Its antenna adopts a planar inverted F-shaped design and is connected to the data processing module through a serial communication interface. The system integrates a signal strength detection function to adjust the transmission power or switch the communication frequency according to the signal quality.

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