A power distribution network foreign frequency signal sensing device, sensing apparatus, system and method

Abstract

A power distribution network frequency signal sensor, sensing device, system, and method are disclosed. A piezoelectric layer and a magnetostrictive layer are tightly bonded together with an adhesive to form a magnetoelectric composite layer. The magnetostrictive layer senses changes in the magnetic field caused by an injected frequency signal and utilizes the magnetostrictive effect to generate stress deformation, which is then transmitted to the piezoelectric layer. The piezoelectric layer converts this stress deformation into a voltage output. The corresponding magnetostrictive-piezoelectric material parameters are selected based on the magnitude of the AC magnetic field strength generated by the injected frequency signal at the sensor's mounting location and the required voltage output value from the piezoelectric layer. The structural characteristic parameters of the magnetoelectric composite layer are determined based on the frequency of the injected frequency signal. The sensor and sensing device are used to identify the magnitude of the injected frequency signal current. This invention offers significant performance advantages, including high sensitivity, adjustable frequency selection, low dependence on injected current intensity, strong anti-interference capability, simple structure, and low cost.

Description

Technical Field

[0001] This invention belongs to the field of signal sensing devices, and more specifically, relates to a power distribution network frequency signal sensing device. Background Technology

[0002] Currently, my country's power distribution network is widely distributed and vast, encompassing various electrical equipment and presenting a complex power supply and consumption environment. Consequently, my country's power distribution network suffers from problems such as untimely and inaccurate acquisition of topology relationships. Unauthorized changes to lines by users are frequent occurrences, and there is a lack of effective technical solutions to establish correct topology hierarchies. Accurate acquisition of power distribution network topology relationships is a crucial foundation for power line planning and abnormal line loss management. For medium and low voltage power distribution networks, single-phase grounding faults are among the most common faults. Failure to correctly identify and promptly disconnect these faults can lead to more serious secondary faults, jeopardizing the safe operation of the system. Therefore, it is essential to quickly identify and disconnect faulty lines in the early stages of a fault.

[0003] To meet the needs of power grid topology identification, methods such as power frequency zero-crossing sequence correlation analysis, power outage record correlation analysis, and hourly voltage curve correlation analysis have been developed. However, these methods have problems such as low accuracy and limited applicability.

[0004] Methods for identifying single-phase grounding faults include those based on steady-state and transient information, as well as intelligent algorithms that integrate fault information. However, these methods have their own limitations, such as failure due to factors like arc suppression coils, or difficulty in capturing relevant signals with existing data acquisition devices.

[0005] Active current injection is currently the preferred technology for identifying power grid topology and locating ground faults. Its principle involves injecting a different frequency characteristic signal into the power frequency current signal. This injected signal is then sensed by a sensor to identify the line topology and determine ground faults. Compared to other methods, active signal injection has advantages such as high success rate, simple principle, and independence from the neutral grounding method.

[0006] However, various interference sources exist in power grid systems, such as harmonics and noise, which may confuse or mask current signals with different frequencies. Therefore, the sensitivity and accuracy of sensing devices are crucial. Existing current sensors mainly include current transformers, resistive current sensors, and Hall effect sensors. However, current transformers are relatively bulky; resistive current sensors have poor applicability for detecting current injected into the power grid; and Hall effect sensors are susceptible to interference from external magnetic fields, limiting their applicability.

[0007] CN117117965A discloses a distribution network topology identification system, method, and apparatus based on a magnetic current sensor. It employs a current transmitting device and a magnetic current sensor. The current transmitting device injects a characteristic current signal of a preset frequency into the distribution network. The magnetic current sensor collects current signals from the distribution network lines, filters out background current signals, and obtains a detection signal for identifying the distribution network topology. This patent uses many components, resulting in high cost and large size, and the injected current can only be adjusted based on the bending resonant frequency of existing magnetic current sensors.

[0008] CN107482112A discloses a permanent magnet-piezoelectric magnetoelectric composite material, which comprises a piezoelectric material and a permanent magnet material. The piezoelectric material is a polarized sheet or strip structure, with metal electrodes attached to its opposite surfaces to form electrode surfaces. At least one permanent magnet material is fixed to the electrode surface of the piezoelectric material. This patent only allows for adjustment of the resonant frequency through continuous experimentation, without any corresponding formula guidance. Summary of the Invention

[0009] To address the technical problems of existing sensing devices being large in size and cost, and only able to adjust the injected current based on the bending resonant frequency of existing magnetic current sensors, this invention provides a power distribution network heterogeneous frequency signal sensing device.

[0010] The present invention adopts the following technical solution.

[0011] A power distribution network frequency signal sensor device includes a magnetostrictive layer and a piezoelectric layer; characterized in that:

[0012] The magnetostrictive layer is symmetrically disposed on the upper and lower sides of the piezoelectric layer;

[0013] The piezoelectric layer and the magnetostrictive layer are tightly bonded together with an adhesive to form a magnetoelectric composite layer;

[0014] The magnetostrictive layer is used to sense the magnetic field changes caused by the measured heterogeneous signal, and uses the magnetostrictive effect to generate stress deformation which is transmitted to the piezoelectric layer, which converts the stress deformation into voltage output.

[0015] Select the corresponding magnetostrictive-piezoelectric material parameters based on the magnitude of the AC magnetic field strength generated by the measured heterofrequency signal at the installation location of the heterofrequency signal sensor and the set piezoelectric layer voltage output threshold.

[0016] The structural characteristic parameters of the magnetoelectric composite layer are determined based on the frequency value of the heterogeneous signal to be tested.

[0017] The present invention further includes the following preferred embodiments.

[0018] At the installation location of the heterogeneous frequency signal sensor, the corresponding magnetostrictive-piezoelectric material parameters are selected based on the relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the heterogeneous frequency signal to be measured. The formula for the relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the heterogeneous frequency signal to be measured is as follows:

[0019]

[0020] in, It is the piezoelectric layer voltage output value of the heterogeneous frequency signal sensor. It is the piezoelectric layer resonance quality factor. It refers to the AC magnetic field strength that can be sensed at the installation location of the heterogeneous frequency signal sensor. It is the piezomagnetic coefficient of the magnetostrictive layer. It is the coupling factor of the magnetostrictive layer. It is the piezoelectric coefficient of the piezoelectric layer. It is the thickness of the piezoelectric layer. It is the vacuum permittivity. It is the relative permittivity of the magnetostrictive layer;

[0021] Select the magnetostrictive-piezoelectric material parameters that meet the set voltage output threshold requirements of the heterogeneous frequency signal sensor device according to the above formula, and select the corresponding magnetostrictive-piezoelectric material and piezoelectric layer thickness according to the determined magnetostrictive-piezoelectric material parameters;

[0022] The parameters of the magnetostrictive-piezoelectric material include the piezoelectric layer resonance quality factor, the magnetostrictive layer piezomagnetic coefficient, the magnetostrictive layer coupling factor, the piezoelectric layer piezoelectric coefficient, and the magnetostrictive layer relative permittivity.

[0023] Magnetostrictive-piezoelectric material systems are selected from the following three types:

[0024] The first type: magnetic ferrite-piezoelectric ceramic;

[0025] The second type: Magnetic alloy - piezoelectric polymer / ceramic / single crystal;

[0026] The third type: magnetic alloy - flexible interdigitated electrode - piezoelectric fiber;

[0027] Among them, flexible interdigitated electrodes are a type of flexible electrode.

[0028] The thickness of the magnetostrictive layers on both the top and bottom sides of the piezoelectric layer is calculated using the following formula:

[0029] ;

[0030] Where w is the thickness of the magnetostrictive layer, and the thickness of the magnetostrictive layer on both the top and bottom sides is equal to w;

[0031] The relationship between the thickness of the magnetoelectric composite layer and the thicknesses of the magnetostrictive layer and the piezoelectric layer is as follows:

[0032] ;

[0033] Where d is the thickness of the magnetoelectric composite layer.

[0034] The bending resonant frequency of the magnetoelectric composite layer is determined by the following formula:

[0035]

[0036] in, ρ is the bending resonant frequency of the magnetoelectric composite layer; l is the length of the magnetoelectric composite layer; ρ is the average density of the magnetoelectric composite layer; s is the average flexibility coefficient of the magnetoelectric composite layer; n is a positive integer representing the vibration level of the magnetoelectric composite layer.

[0037] Based on the frequency of the external frequency signal to be measured, the length of the magnetoelectric composite layer in the power distribution network external frequency signal sensor is adjusted to obtain the bending resonant frequency of the magnetoelectric composite layer when the vibration level is 1, which is the same as the frequency of the external frequency signal to be measured.

[0038] This application also discloses a power distribution network frequency signal sensing device based on the aforementioned power distribution network frequency signal sensor, which further includes an amplification and filtering module, a rectification module, a voltage stabilization module, and a microcontroller unit; characterized in that:

[0039] The power distribution network frequency signal sensor senses the magnetic field change caused by the measured frequency signal and converts it into a voltage output to the amplification and filtering module.

[0040] The amplification and filtering module is used to amplify the voltage signal output by the heterogeneous frequency signal sensor and filter out noise signals.

[0041] The rectifier module is used to smoothly output the amplified and filtered voltage signal to the input terminal of the voltage regulator module;

[0042] The voltage regulator module is used to stabilize the smoothed voltage and then output it to the microcontroller unit;

[0043] The microcontroller receives the voltage value output by the voltage regulator module, and restores the magnitude of the measured frequency current based on the relationship between the calibrated piezoelectric layer voltage output value of the frequency signal sensor and the frequency current, or derives the magnetic field strength sensed by the frequency signal sensor based on the output voltage of the frequency signal sensor, and then calculates the magnitude of the measured frequency current based on the relationship between the magnetic field strength of the frequency signal and the magnitude of the frequency current.

[0044] The present invention further includes the following preferred embodiments.

[0045] In the microcontroller unit, the magnetic field strength sensed by the frequency signal sensor is calculated from the output voltage of the frequency signal sensor based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the frequency signal to be measured.

[0046] This application also discloses a distribution network frequency signal sensing system based on the aforementioned distribution network frequency signal sensing device, including a frequency signal injection device and a distribution network frequency signal sensing device; characterized in that:

[0047] The heterogeneous frequency signal injection device injects a selected heterogeneous frequency current signal into the power distribution network;

[0048] The power distribution network frequency signal sensing device identifies and restores the magnitude of the injected frequency current.

[0049] The present invention further includes the following preferred embodiments.

[0050] The frequency of the heterogeneous current signal injected into the distribution network is selected to be 200~1000Hz, and it must avoid the odd and even harmonic frequencies of the power frequency, and the amplitude of the heterogeneous current signal does not exceed 100mA.

[0051] This application also discloses a distribution network inter-frequency signal sensing method based on the aforementioned distribution network inter-frequency signal sensing system, characterized in that the method includes the following:

[0052] A variable frequency current signal with a defined frequency and amplitude is injected at a designated location on the power grid using a variable frequency signal injection device.

[0053] Install distribution network frequency signal sensing devices at distribution network monitoring node locations;

[0054] Based on the amplitude of the different frequency signal current and the set piezoelectric layer voltage output threshold required by the power distribution network different frequency signal sensing device, the magnetostrictive-piezoelectric material parameters in the power distribution network different frequency signal sensing device are selected. The characteristic parameters of the magnetoelectric composite layer structure in the power distribution network different frequency signal sensing device are adjusted according to the frequency value of the injected different frequency signal to be measured, so that the bending resonant frequency of the magnetoelectric composite layer is the same as the frequency of the injected different frequency signal.

[0055] The magnitude of the injected inter-frequency current signal is identified and restored by the inter-frequency signal sensing device of the power distribution network.

[0056] The present invention also provides an electronic device, including a processor and a storage medium; characterized in that the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the distribution network frequency signal sensing method of the distribution network frequency signal sensing system.

[0057] The present invention also provides a computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the distribution network inter-frequency signal sensing method of the distribution network inter-frequency signal sensing system.

[0058] The beneficial effects of this invention are that, compared with the prior art, the distribution network frequency signal sensing device proposed in this invention has outstanding performance advantages such as high sensitivity, adjustable frequency selection and identification, low dependence on injection current intensity, strong anti-interference ability, simple structure, low cost, and large-scale and widespread deployment. Attached Figure Description

[0059] Figure 1 This is a schematic diagram illustrating the working principle of a heterogeneous frequency signal sensor.

[0060] Figure 2 This is a schematic diagram of the basic structure of a heterogeneous frequency signal sensor.

[0061] Figure 3 This is a schematic diagram of the sensing characteristics of a heterogeneous frequency signal sensing device;

[0062] Figure 4 This is a schematic diagram of a heterogeneous frequency signal sensing device. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this invention.

[0064] This invention proposes a power distribution network frequency signal sensor device, comprising a magnetostrictive layer and a piezoelectric layer; characterized in that:

[0065] See appendix Figure 1 This is a basic schematic diagram of a heterogeneous frequency signal sensor. Its core principle is based on the magnetoelectric coupling technology of "current-induced magnetic field-stress change-voltage signal". The magnetostrictive layer is formed by bonding multiple layers of magnetostrictive material with a bonding material, and has a magnetostrictive effect. The magnetostrictive layer can sense changes in the external magnetic field and use the magnetostrictive effect to generate stress changes that are transmitted to the piezoelectric layer. The piezoelectric layer is composed of piezoelectric material and flexible electrode material, and has a piezoelectric effect. Through the magnetoelectric stress coupling effect generated by the combination of the piezoelectric layer and the magnetostrictive layer, the stress deformation generated by the deformation of the magnetostrictive layer on the piezoelectric layer is converted into voltage by the piezoelectric material, which is output by two flexible electrodes symmetrically arranged on the upper and lower sides of the piezoelectric material in the piezoelectric layer.

[0066] See appendix Figure 2 The basic structure of this heterogeneous frequency signal sensor consists of a magnetostrictive layer composed of multiple layers of magnetostrictive material, symmetrically arranged on the upper and lower sides of a piezoelectric layer composed of piezoelectric material, forming a magnetoelectric composite layer. The heterogeneous frequency signal sensor senses a magnetic field component H parallel to the long side of its magnetoelectric composite layer. The relationship between the thickness of the magnetoelectric composite layer and the thicknesses of the magnetostrictive and piezoelectric layers is as follows:

[0067] ;

[0068] Where w is the thickness of the magnetostrictive layer, the magnetostrictive layers on the upper and lower sides of the piezoelectric layer are of equal thickness, both being w, z is the thickness of the piezoelectric layer, and d is the thickness of the magnetoelectric composite layer.

[0069] The piezoelectric layer and the magnetostrictive layer are tightly bonded together by an adhesive to form a magnetoelectric composite layer; wherein the adhesive should be a material with a high elastic modulus and a low dielectric constant.

[0070] The basic parameters of the magnetostrictive layer mainly include length, thickness, number of layers, density, flexibility coefficient, piezoelectric coefficient, dielectric constant, and coupling factor. Among these, length, thickness, and number of layers are structural features, while the other parameters are material features. The flexibility coefficient is an intrinsic parameter of the magnetostrictive layer, describing the material's deformation capability under stress. A higher flexibility coefficient indicates easier deformation, therefore a larger value is better. The coupling factor is also an intrinsic parameter of the magnetostrictive layer, representing the efficiency of strain conversion from the magnetostrictive layer to the piezoelectric layer.

[0071] The basic parameters of the piezoelectric layer mainly include length, thickness, density, flexibility coefficient, piezoelectric coefficient, and resonance quality factor. Length and thickness are structural characteristics, while the other parameters are material characteristics. The piezoelectric layer material exhibits high piezoelectric coefficient properties after polarization. The flexibility coefficient has the same meaning as in the magnetostrictive layer and is also a parameter inherent to the piezoelectric layer itself.

[0072] At the installation location of the heterogeneous frequency signal sensor, the corresponding magnetostrictive-piezoelectric material parameters are selected based on the relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the heterogeneous frequency signal to be measured, as well as the set voltage output threshold of the heterogeneous frequency signal sensor. The magnetostrictive-piezoelectric material parameters include the piezoelectric layer resonance quality factor, the magnetostrictive layer piezomagnetic coefficient, the magnetostrictive layer coupling factor, the piezoelectric coefficient, and the relative permittivity of the magnetostrictive layer.

[0073] The relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the measured heterogeneous frequency signal can be described by the following equation:

[0074]

[0075] in, It is the piezoelectric layer voltage output value of the heterogeneous frequency signal sensor. It is the resonant quality factor of the piezoelectric layer. The AC magnetic field strength that can be sensed at the installation location of the heterogeneous frequency signal sensor is the AC magnetic field strength. is the piezomagnetic coefficient of the magnetostrictive layer, and k is the coupling factor of the magnetostrictive layer. is the piezoelectric coefficient of the piezoelectric layer, and z is the thickness of the piezoelectric layer. It is the vacuum permittivity. = 8.854187817 × 10-12 F / m, It is the relative permittivity of the magnetostrictive layer.

[0076] In the calculation process of this formula and subsequent formulas, the structural characteristic unit of the magnetoelectric composite layer, magnetostrictive material and piezoelectric material is m;

[0077] From the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the measured heterogeneous signal, it can be seen that the larger the piezomagnetic coefficient of the magnetostrictive material, the better; and the larger the piezoelectric coefficient of the piezoelectric material, the better.

[0078] Based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the measured heterofrequency signal, select the magnetostrictive-piezoelectric material parameters that meet the set heterofrequency signal sensor voltage output threshold requirements, and select the corresponding magnetostrictive-piezoelectric material and piezoelectric layer thickness based on the determined magnetostrictive-piezoelectric material parameters;

[0079] Currently, the magnetostrictive-piezoelectric material systems that can achieve relatively good results mainly include:

[0080] (1) Magnetic ferrite-piezoelectric ceramic PZT;

[0081] Preferably, the magnetic ferrite includes CFO, NFO, etc.;

[0082] (2) Magnetic alloy-piezoelectric polymer / ceramic / single crystal Pb(Mg1 / 3Nb2 / 3)O3-PbTiO3;

[0083] Preferably, the magnetic alloys include Terfenol-D, Ni, Metglas, etc.

[0084] (3) Magnetic alloy-flexible interdigitated electrode-piezoelectric fiber;

[0085] Among them, flexible interdigitated electrodes are a type of flexible electrode used to output the voltage generated by the piezoelectric layer;

[0086] Preferably, the piezoelectric fibers include PZT, PMN-PT, PZN-PT, etc.

[0087] The thickness of the magnetostrictive layers on both the top and bottom sides of the piezoelectric layer is calculated using the following formula:

[0088] ;

[0089] Where w is the thickness of the magnetostrictive layer, and the thickness of the magnetostrictive layer on both the top and bottom sides is equal, both being w; at this time, the ratio of the magnetostrictive layer thickness to the magnetoelectric composite layer thickness is 0.56, which can minimize the noise voltage in the voltage output, thereby obtaining the best signal output;

[0090] The bending resonant frequency of the magnetoelectric composite layer is determined by the following formula:

[0091]

[0092] Where f is the bending resonant frequency, l is the length of the magnetoelectric composite layer, ρ is the average density of the magnetoelectric composite layer, s is the average flexibility coefficient of the magnetoelectric composite layer, and n is a positive integer representing the vibration level of the magnetoelectric composite layer. When the vibration level is 1, i.e., n=1, the calculated bending resonant frequency that is the same as the frequency of the target signal is the bending resonant frequency with the highest matching degree between the target signal and the target signal, which maximizes the piezoelectric layer voltage output value of the target signal. When the vibration level is 2, i.e., n=2, the calculated bending resonant frequency that is the same as the frequency of the target signal is the bending resonant frequency with the second highest matching degree between the target signal and the target signal, and the piezoelectric layer voltage output value of the target signal is the second largest at this bending resonant frequency. The larger the value of the vibration level n, the lower the matching degree between the target signal and the target signal at the calculated bending resonant frequency, and the smaller the piezoelectric layer voltage output value of the target signal.

[0093] From the above four formulas and appendix Figure 3 It can be seen that the structural characteristics of the magnetostrictive layer and the piezoelectric layer affect the resonant point of the magnetoelectric composite layer, i.e., the bending resonant frequency. This affects the voltage output of the magnetoelectric composite layer, so the structural characteristics of the magnetostrictive layer and the piezoelectric layer need to be adjusted.

[0094] The basic modulation principle of the magnetostrictive layer is shown in the formula for the bending resonant frequency of the magnetoelectric composite layer: Bending resonant frequency of the magnetoelectric composite layer The bending resonant frequency of the magnetostrictive composite layer increases with the number of magnetostrictive layers, and the increase is greater with the number of layers; The length of the magnetostrictive layer decreases as the length of the magnetostrictive layer increases. Therefore, based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the measured frequency signal, after determining the magnetostrictive-piezoelectric material and the thickness of the piezoelectric layer, the length of the magnetoelectric composite layer in the power distribution network frequency signal sensor is adjusted according to the frequency of the measured frequency signal to obtain the bending resonant frequency of the magnetoelectric composite layer when the vibration level is 1, which is the same as the frequency of the measured frequency signal.

[0095] This invention also discloses a distribution network frequency signal sensing device based on the aforementioned distribution network frequency signal sensor, see appendix. Figure 4 It also includes an amplification and filtering module, a rectification module, a voltage regulation module, and an MCU microcontroller unit, characterized in that:

[0096] The power distribution network frequency signal sensor detects the change in the magnetic field component parallel to the long side of the magnetoelectric composite layer of the sensor, caused by the frequency signal under test, and converts it into a voltage output. Output voltage The signal is transmitted to the amplification and filtering module; the magnetic field component parallel to the long side of the magnetoelectric composite layer is generated by the selected frequency and amplitude of the measured heterogeneous signal.

[0097] The amplification and filtering module is used to amplify the voltage signal output by the heterogeneous frequency signal sensor, filter out noise signals, and output a voltage signal. ;

[0098] The rectifier module is used to convert the amplified and filtered voltage signal. The smoothed output is a voltage signal. , to voltage signal Output to the input terminal of the voltage regulator module;

[0099] The voltage regulator module is used to stabilize and smooth the output voltage signal. The stabilized voltage signal is then output as a voltage signal. , to voltage signal Output to the microcontroller unit;

[0100] The microcontroller receives the voltage value output by the voltage regulator module and, based on the calibrated relationship between the piezoelectric layer voltage output value of the frequency signal sensor and the frequency current, reconstructs the magnitude of the frequency current to be measured. Alternatively, based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the frequency signal to be measured, it derives the magnetic field strength sensed by the frequency signal sensor from the output voltage of the frequency signal sensor, and then reconstructs the magnitude of the frequency current to be measured based on the relationship between the magnetic field strength of the frequency signal and the magnitude of the frequency current.

[0101] The application also discloses a distribution network inter-frequency signal sensing system based on the aforementioned distribution network inter-frequency signal sensing device, including an inter-frequency signal injection device and a distribution network inter-frequency signal sensing device; characterized in that:

[0102] The aforementioned heterogeneous frequency signal injection device is used to actively inject heterogeneous frequency current signals into the power distribution network. The frequency of the heterogeneous frequency current signal is selected to be 200~1000Hz, and it must avoid the odd and even harmonic frequencies of the power frequency. Furthermore, the amplitude of the heterogeneous frequency current signal does not exceed 100mA.

[0103] The power distribution network frequency signal sensing device selects corresponding magnetostrictive-piezoelectric material parameters based on the relationship formula between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the measured frequency signal, as well as the set piezoelectric layer voltage output threshold. It then selects the corresponding magnetostrictive-piezoelectric material and piezoelectric layer thickness based on these parameters. Finally, it adjusts the length of the magnetoelectric composite layer in the power distribution network frequency signal sensor according to the injected frequency signal frequency, obtaining the bending resonant frequency of the magnetoelectric composite layer when the vibration level is 1, which is the same as the injected frequency signal frequency. This accurately identifies and reconstructs the injected frequency signal, meeting the needs of actively injected frequency current signal identification in application scenarios such as power distribution network topology recognition and single-phase grounding faults.

[0104] See appendix Figure 3 To demonstrate the voltage output response obtained by identifying 100mA heterogeneous current signals of different frequencies using the heterogeneous frequency signal sensing device of this invention, it is evident that the heterogeneous frequency signal sensing device exhibits significant resonance characteristics for heterogeneous current signals with the same frequency as the resonant point of the heterogeneous frequency signal sensor. Therefore, by adjusting the bending resonant frequency of the heterogeneous frequency signal sensor according to the frequency of the injected heterogeneous frequency signal, the heterogeneous frequency signal sensing device can accurately sense the injected heterogeneous frequency current signal, where the resonant point is the bending resonant frequency. (Appendix) Figure 3 This fully demonstrates the sensitivity and selectivity of the device of the present invention in detecting current signals.

[0105] This invention also discloses a method for sensing inter-frequency signals in a distribution network based on the aforementioned distribution network inter-frequency signal sensing system, specifically including:

[0106] A variable frequency current signal with a defined frequency and amplitude is injected at a designated location on the power grid using a variable frequency signal injection device.

[0107] Install distribution network frequency signal sensing devices at distribution network monitoring node locations;

[0108] Based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the measured heterofrequency signal and the set piezoelectric layer voltage output threshold of the heterofrequency signal sensor, the corresponding magnetostrictive-piezoelectric material parameters are selected. Based on the determined magnetostrictive-piezoelectric material parameters, the corresponding magnetostrictive-piezoelectric material and piezoelectric layer thickness are selected. Then, based on the injected heterofrequency signal frequency, the length of the magnetoelectric composite layer in the power distribution network heterofrequency signal sensor is adjusted to obtain the bending resonant frequency of the magnetoelectric composite layer when the vibration level is 1, which is the same as the injected heterofrequency signal frequency.

[0109] The magnitude of the injected inter-frequency current signal is identified and restored by the inter-frequency signal sensing device of the power distribution network.

[0110] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0111] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0112] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0113] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A power distribution network frequency signal sensor, comprising a magnetostrictive layer and a piezoelectric layer; characterized in that: The magnetostrictive layer is symmetrically disposed on the upper and lower sides of the piezoelectric layer; The piezoelectric layer and the magnetostrictive layer are tightly bonded together with an adhesive to form a magnetoelectric composite layer. At the mounting location of the heterogeneous frequency signal sensor, the corresponding magnetostrictive-piezoelectric material parameters are selected based on the relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the heterogeneous frequency signal to be measured. The formula for the relationship between the piezoelectric layer voltage output value and the AC magnetic field strength generated by the heterogeneous frequency signal to be measured is as follows: ;in, It is the piezoelectric layer voltage output value of the heterogeneous frequency signal sensor. It is the piezoelectric layer resonance quality factor. It refers to the AC magnetic field strength that can be sensed at the installation location of the heterogeneous frequency signal sensor. It is the piezomagnetic coefficient of the magnetostrictive layer. It is the coupling factor of the magnetostrictive layer. It is the piezoelectric coefficient of the piezoelectric layer. It is the thickness of the piezoelectric layer. It is the vacuum permittivity. It is the relative permittivity of the magnetostrictive layer; according to the above formula, select the magnetostrictive-piezoelectric material parameters that meet the set voltage output threshold requirements of the heterogeneous frequency signal sensor device, and select the corresponding magnetostrictive-piezoelectric material and piezoelectric layer thickness according to the determined magnetostrictive-piezoelectric material parameters; wherein, the magnetostrictive-piezoelectric material parameters include the piezoelectric layer resonance quality factor, the magnetostrictive layer piezomagnetic coefficient, the magnetostrictive layer coupling factor, the piezoelectric coefficient, and the relative permittivity of the magnetostrictive layer; The magnetostrictive layer is used to sense the magnetic field changes caused by the measured heterogeneous signal, and uses the magnetostrictive effect to generate stress deformation which is transmitted to the piezoelectric layer, which converts the stress deformation into voltage output. Select the corresponding magnetostrictive-piezoelectric material parameters based on the magnitude of the AC magnetic field strength generated by the measured heterofrequency signal at the installation location of the heterofrequency signal sensor and the set piezoelectric layer voltage output threshold. The structural characteristic parameters of the magnetoelectric composite layer are determined based on the frequency value of the heterogeneous signal to be tested.

2. The power distribution network frequency signal sensor according to claim 1, characterized in that: Magnetostrictive-piezoelectric material systems are selected from the following three types: The first type: magnetic ferrite-piezoelectric ceramic; The second type: Magnetic alloy - piezoelectric polymer / ceramic / single crystal; The third type: magnetic alloy - flexible interdigitated electrode - piezoelectric fiber; Among them, flexible interdigitated electrodes are a type of flexible electrode.

3. The power distribution network frequency signal sensor according to claim 1, characterized in that: The thickness of the magnetostrictive layers on both the top and bottom sides of the piezoelectric layer is calculated using the following formula: ； Where w is the thickness of the magnetostrictive layer, and the thickness of the magnetostrictive layer on both the top and bottom sides is equal to w; The relationship between the thickness of the magnetoelectric composite layer and the thicknesses of the magnetostrictive layer and the piezoelectric layer is as follows: ； Where d is the thickness of the magnetoelectric composite layer.

4. The power distribution network frequency signal sensor device according to claim 1 or 3, characterized in that: The bending resonant frequency of the magnetoelectric composite layer is determined by the following formula: in, ρ is the bending resonant frequency of the magnetoelectric composite layer; l is the length of the magnetoelectric composite layer; ρ is the average density of the magnetoelectric composite layer; s is the average flexibility coefficient of the magnetoelectric composite layer; n is a positive integer representing the vibration level of the magnetoelectric composite layer.

5. The power distribution network frequency signal sensor according to claim 4, characterized in that: Based on the frequency of the external frequency signal to be measured, the length of the magnetoelectric composite layer in the power distribution network external frequency signal sensor is adjusted to obtain the bending resonant frequency of the magnetoelectric composite layer when the vibration level is 1, which is the same as the frequency of the external frequency signal to be measured.

6. A power distribution network heterogeneous frequency signal sensing device based on the heterogeneous frequency signal sensor according to any one of claims 1-5, further comprising an amplification and filtering module, a rectification module, a voltage regulation module, and a microcontroller unit; characterized in that: The power distribution network frequency signal sensor senses the magnetic field change caused by the measured frequency signal and converts it into a voltage output to the amplification and filtering module. The amplification and filtering module is used to amplify the voltage signal output by the heterogeneous frequency signal sensor and filter out noise signals. The rectifier module is used to smoothly output the amplified and filtered voltage signal to the input terminal of the voltage regulator module; The voltage regulator module is used to stabilize the smoothed voltage and then output it to the microcontroller unit; The microcontroller receives the voltage value output by the voltage regulator module, and restores the magnitude of the measured frequency current based on the relationship between the calibrated piezoelectric layer voltage output value of the frequency signal sensor and the frequency current, or derives the magnetic field strength sensed by the frequency signal sensor based on the output voltage of the frequency signal sensor, and then calculates the magnitude of the measured frequency current based on the relationship between the magnetic field strength of the frequency signal and the magnitude of the frequency current.

7. The power distribution network frequency signal sensing device according to claim 6, characterized in that: In the microcontroller unit, the magnetic field strength sensed by the frequency signal sensor is calculated from the output voltage of the frequency signal sensor based on the formula relating the piezoelectric layer voltage output value to the AC magnetic field strength generated by the frequency signal to be measured.

8. A distribution network inter-frequency signal sensing system based on the distribution network inter-frequency signal sensing device according to any one of claims 6-7, comprising an inter-frequency signal injection device and a distribution network inter-frequency signal sensing device; characterized in that: The heterogeneous frequency signal injection device injects a selected heterogeneous frequency current signal into the power distribution network; The power distribution network frequency signal sensing device identifies and restores the magnitude of the injected frequency current.

9. The power distribution network frequency signal sensing system according to claim 8, characterized in that: The frequency of the heterogeneous current signal injected into the distribution network is selected to be 200~1000Hz, and it must avoid the odd and even harmonic frequencies of the power frequency, and the amplitude of the heterogeneous current signal does not exceed 100mA.

10. A method for sensing inter-frequency signals in a distribution network based on the distribution network inter-frequency signal sensing system according to any one of claims 8-9, characterized in that, The method includes the following: A variable frequency current signal with a defined frequency and amplitude is injected at a designated location on the power grid using a variable frequency signal injection device. Install distribution network frequency signal sensing devices at distribution network monitoring node locations; Based on the amplitude of the heterogeneous signal current and the set output threshold of the piezoelectric layer voltage of the heterogeneous signal sensing device in the power distribution network, the magnetostrictive-piezoelectric material parameters in the heterogeneous signal sensing device in the power distribution network are selected. The structural characteristic parameters of the magnetoelectric composite layer in the heterogeneous signal sensing device in the power distribution network are adjusted according to the frequency value of the injected heterogeneous signal so that the bending resonant frequency of the magnetoelectric composite layer is the same as the frequency of the injected heterogeneous signal. The magnitude of the injected inter-frequency current signal is identified and restored by the inter-frequency signal sensing device of the power distribution network.

11. An electronic device, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the distribution network frequency signal sensing method according to claim 10.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the distribution network frequency signal sensing method of claim 10.

Images