Current measuring device and circuit monitoring system

Abstract

The invention discloses a current measuring device and a circuit monitoring system, and relates to the field of current detection, a fluxgate iron core and a Rogowski coil in the device are both of a circular ring structure, are arranged in parallel in the axis direction and are spaced by a preset distance, and the central axes of the fluxgate iron core and the Rogowski coil are coaxial; the magnetization module is used for magnetizing the fluxgate iron core so that the magnetization intensity of the fluxgate iron core reaches a preset maximum intensity value; and the processing module is also connected with the Rogowski coil and is used for performing fusion processing on a first sampling signal output by the fluxgate iron core through the winding and a second sampling signal output by the Rogowski coil to correspondingly obtain a measurement signal when a wire through which the current to be measured flows passes through the centers of the fluxgate iron core and the Rogowski coil. According to the scheme, the fluxgate iron core and the winding of the fluxgate iron core are combined with the Rogowski coil, and accurate measurement of current in a broadband range is facilitated through respective sampling and subsequent signal fusion.

Description

Technical Field

[0001] The present invention relates to the technical field of current detection, and in particular to a current measuring device and a circuit monitoring system. Background Art

[0002] Power systems include current sensors for signal measurement. Current current sensors perform well in measuring current signals within the fundamental frequency range. As the trend toward power electronics in power systems becomes increasingly pronounced, this introduces a significant amount of broadband noise and harmonics, necessitating current sensors capable of measuring broadband current. However, current non-contact current sensors, which are mostly based on the principle of electromagnetic induction, are limited by their inherent structure and induction mechanism. Their respective application scenarios and measurement ranges vary, making it difficult to measure current across a wide frequency range. This hinders reliable monitoring of power systems and hinders practical application.

[0003] Therefore, how to provide a current measurement solution that can reliably and accurately achieve a wide frequency range is an urgent problem to be solved. Summary of the Invention

[0004] In view of this, the present invention provides a current measuring device and circuit monitoring system, which combines a fluxgate core and its winding with a Rogowski coil, thereby breaking through the frequency band limitation of the traditional single sensing principle and realizing accurate current measurement within a wide frequency range.

[0005] To solve the above technical problems, the present application provides a current measuring device, comprising a fluxgate core, a winding, a Rogowski coil, a magnetization module, and a processing module; the fluxgate core and the Rogowski coil are both annular structures, the fluxgate core and the Rogowski coil are arranged parallel to each other along an axis and separated by a preset distance, and the central axis of the fluxgate core is coaxial with the central axis of the Rogowski coil; The magnetization module is connected to the winding, the winding is wound around the fluxgate core and is also connected to the processing module after being wound, and the magnetization module is used to magnetize the fluxgate core so that the magnetization intensity of the fluxgate core reaches a preset maximum intensity value; The processing module is also connected to the Rogowski coil and is used to fuse the first sampling signal output by the fluxgate core through the winding and the second sampling signal output by the Rogowski coil when the conductor through which the current to be measured flows passes through the center of the fluxgate core and the Rogowski coil, so as to obtain a measurement signal corresponding to the current to be measured.

[0006] Furthermore, 5mm≤the preset distance≤3cm.

[0007] Furthermore, the processing module includes a signal separation module, a DC processing module, a low-frequency AC processing module, a high-frequency AC processing module and a data fusion module; The input end of the signal separation module is connected to the winding, the first output end is connected to the input end of the DC processing module, and the second output end is connected to the input end of the low-frequency AC processing module, and is used to perform signal separation on the first sampling signal output by the fluxgate core through the winding, so as to output the separated DC sampling signal to the DC processing module, and output the separated first AC sampling signal to the low-frequency AC processing module; The output end of the DC processing module is connected to the data fusion module, and is used to demodulate the DC sampling signal to obtain a DC measurement signal; The output end of the low-frequency AC processing module is connected to the data fusion module, and is used to process the first AC sampling signal to obtain a first AC measurement signal with a frequency less than a first preset frequency; The input end of the high-frequency AC processing module is connected to the Rogowski coil, and the output end is connected to the data fusion module, and is used to process the second sampling signal output by the Rogowski coil to obtain a second AC measurement signal with a frequency greater than a second preset frequency, where the first preset frequency is equal to the second preset frequency; The data fusion module is used to fuse the DC measurement signal, the first AC measurement signal, and the second AC measurement signal to obtain a measurement signal corresponding to the current to be measured.

[0008] Furthermore, the processing module also includes a sampling resistor and a voltage acquisition module; One end of the sampling resistor is grounded, and the other end is connected to the winding and then connected to the input end of the voltage acquisition module; The output end of the voltage acquisition module is connected to the input end of the signal separation module.

[0009] Furthermore, the low-frequency AC processing module includes a low-frequency data processing module and a low-pass filter connected in sequence; The low-frequency data processing module is used to demodulate the first AC sampling signal to obtain a corresponding first AC intermediate signal; The low-pass filter is used to process the first AC intermediate signal to output a first AC measurement signal having a frequency lower than its own corresponding first cut-off frequency.

[0010] Furthermore, the high-frequency AC processing module includes an integration module, a high-frequency data processing module and a high-pass filter connected in sequence; The integration module is used to integrate the second sampling signal output by the Rogowski coil to obtain a second AC intermediate signal; The high-frequency data processing module is used to perform noise removal and ripple filtering on the second AC intermediate signal to obtain a third AC intermediate signal; The high-pass filter is used to process the third AC intermediate signal to output a second AC measurement signal having a frequency greater than its own corresponding second cutoff frequency, where the second cutoff frequency is equal to the first cutoff frequency.

[0011] Furthermore, the current measuring device further includes an upper monitoring module connected to the processing module; The processing module is further configured to send the measurement signal to the upper monitoring module.

[0012] Furthermore, the current measuring device further includes a correction wire and a correction source module; The correction wire is used to pass through the center of the fluxgate core and the Rogowski coil and then be connected to the correction source module; The correction source module is used to output a standard current, so as to determine the current measurement accuracy of the current measurement device according to the standard current and the corresponding correction measurement signal output by the processing module.

[0013] Furthermore, the current measuring device further includes a shielding cover; The Rogowski coil and the fluxgate core wound with the winding are both arranged in the shielding cover.

[0014] In order to solve the above technical problems, the present invention further provides a circuit monitoring system, comprising the current measuring device as described above.

[0015] The beneficial effects of this application are: The present application provides a current measuring device and a circuit monitoring system. The fluxgate core and the Rogowski coil in the device are both annular structures. The fluxgate core and the Rogowski coil are arranged parallel to each other along the axis direction and separated by a preset distance, and the central axis of the fluxgate core is coaxial with the central axis of the Rogowski coil. A magnetization module is connected to a winding, which is wound around the fluxgate core and is also connected to a processing module after winding. The magnetization module is used to magnetize the fluxgate core so that the magnetization intensity of the fluxgate core reaches a preset maximum intensity value. The processing module is also connected to the Rogowski coil and is used to fuse a first sampling signal output by the fluxgate core through the winding and a second sampling signal output by the Rogowski coil when a conductor through which the current to be measured flows passes through the center of the fluxgate core and the Rogowski coil, so as to obtain a measurement signal corresponding to the current to be measured. It can be seen that the combination of the fluxgate core and its winding with the Rogowski coil in this scheme is conducive to breaking through the frequency band limitation of the single sensing principle. Through separate sampling and subsequent signal fusion, it is conducive to achieving accurate measurement of current in a wide frequency range, which is beneficial to practical applications.

[0016] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 A schematic structural diagram of a current measuring device provided by the present invention; Figure 2 This is a structural schematic diagram of another current measuring device provided by the present invention. DETAILED DESCRIPTION

[0018] The core of the present invention is to provide a current measurement device and circuit monitoring system, which combines the fluxgate core and its winding with the Rogowski coil, which helps to break through the frequency band limitation of the traditional single sensing principle and realize accurate measurement of current in a wide frequency range.

[0019] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0020] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0021] Please refer to Figure 1 , Figure 1 This is a structural schematic diagram of a current measuring device provided by the present invention.

[0022] The current measuring device includes a fluxgate core 11, a winding 12, a Rogowski coil 21, a magnetization module, and a processing module 3. The fluxgate core 11 and the Rogowski coil 21 are both annular structures. The fluxgate core 11 and the Rogowski coil 21 are arranged parallel to each other along the axis and separated by a preset distance. The central axis of the fluxgate core 11 is coaxial with the central axis of the Rogowski coil 21. The magnetization module is connected to the winding 12, which is wound around the fluxgate core 11 and is also connected to the processing module 3 after being wound. The magnetization module is used to magnetize the fluxgate core 11 so that the magnetization intensity of the fluxgate core 11 reaches a preset maximum intensity value; The processing module 3 is also connected to the Rogowski coil 21, and is used to fuse the first sampling signal output by the fluxgate core 11 through the winding 12 and the second sampling signal output by the Rogowski coil 21 when the conductor through which the current to be measured flows passes through the center of the fluxgate core 11 and the Rogowski coil 21, so as to obtain a measurement signal corresponding to the current to be measured.

[0023] In this embodiment, the current measuring device includes but is not limited to monitoring of broadband current signals applied to a substation site. The current to be measured can be a direct current or an alternating current, which is not particularly limited here. Specifically, the Rogowski coil 21 here is a Rogowski coil, and the fluxgate core 11 and the Rogowski coil 21 are both annular structures, such as Figure 1 shown, and Figure 1Due to the limitation of the focus of the picture and to avoid confusion in the connection, only a section of winding 12 is wound around the fluxgate core 11 as a winding diagram, and the connection between the magnetization module and the winding 12 is temporarily omitted; the preset distance referred to here is intended to enable the low-frequency magnetic field of the fluxgate core 11 to effectively cover the sensitive area of ​​the Rogowski coil 21, and to ensure that the magnetic fields therebetween do not interfere with each other; the preset distance is controlled at a few millimeters to centimeters; in some embodiments, 5mm≤preset distance≤3cm. The principle of this setting is that when the preset distance exceeds 3cm, the low-frequency magnetic field of the fluxgate core 11 may not be able to effectively cover the sensitive area of ​​the Rogowski coil 21, resulting in discontinuous frequency band connection during subsequent signal fusion; when the preset distance is less than 5mm, the magnetic fields therebetween may interfere with each other, affecting the measurement accuracy.

[0024] The magnetization module is used to magnetize the fluxgate core 11 so that the magnetization intensity of the fluxgate core 11 reaches a preset maximum intensity value, that is, the fluxgate core 11 is magnetized to saturation. The magnetization module includes but is not limited to a self-excited oscillation circuit. The specific circuit form of the self-excited oscillation circuit is not particularly limited here and can be flexibly set according to actual needs; the winding 12 is wound around the fluxgate core 11 to form a fluxgate mutual inductor, and the wound winding 12 is also connected to the processing module 3, and the two output ends of the Rogowski coil 21 are also connected to the processing module 3, such as Figure 1 shown.

[0025] In practical applications, the conductor through which the current to be measured flows is passed through the center of the fluxgate core 11 and the center of the Rogowski coil 21. Specifically, the fluxgate transformer can accurately and reliably measure direct current and low-frequency alternating current, and the Rogowski coil 21 can accurately and reliably measure high-frequency alternating current. It can be seen that the combination of the fluxgate core 11 and its winding 12 with the Rogowski coil 21 in this application can break through the frequency band limitation of a single sensing principle and achieve accurate measurement of current in a wide frequency range.

[0026] It is understandable that in actual applications, the signal components of the current to be measured are complex and are usually not composed of components of a single frequency. Low-frequency components and high-frequency components may exist in the current to be measured at the same time. DC components or attenuated DC components may also exist in the AC current. At this time, the outputs of the fluxgate transformer and the Rogowski coil 21 are both valid, that is, the fluxgate core 11 outputs a first sampling signal through the winding 12, and the Rogowski coil 21 outputs a second sampling signal. The processing module 3 performs a fusion process on the first sampling signal and the second sampling signal. The fusion process is to fuse the sampling signals of different frequency components to ensure that the signal timing is aligned and then output a measurement signal corresponding to the current to be measured.

[0027] In addition, it should be noted that the fluxgate core 11 and the Rogowski coil 21 need to be as follows: Figure 1 As shown, they are strictly coaxially aligned and parallel to ensure that the magnetic field generated by the current to be measured is evenly distributed inside the two. If there is an offset, the magnetic field distribution will be asymmetric, resulting in errors in the measurement of DC current and low-frequency AC current by the fluxgate transformer. The measurement results of high-frequency AC current by the Rogowski coil 21 will also be distorted during subsequent integration.

[0028] In summary, the present application provides a current measuring device that combines the fluxgate core 11 and the winding 12, as well as the Rogowski coil 21, to collaboratively measure the same current to be measured, breaking through the frequency band limitation of a single sensing principle and widening the measurement frequency band. Through respective sampling and subsequent signal fusion, it is beneficial to achieve accurate measurement of current in a wide frequency range. It is also small in size and light in weight, which is conducive to practical application.

[0029] In some embodiments, the processing module 3 includes a signal separation module 31 , a DC processing module 32 , a low-frequency AC processing module 33 , a high-frequency AC processing module 34 , and a data fusion module 35 ; The input end of the signal separation module 31 is connected to the winding 12, the first output end is connected to the input end of the DC processing module 32, and the second output end is connected to the input end of the low-frequency AC processing module 33. The signal separation module 31 is used to separate the first sampling signal output by the fluxgate core 11 through the winding 12, so as to output the separated DC sampling signal to the DC processing module 32, and output the separated first AC sampling signal to the low-frequency AC processing module 33; The output end of the DC processing module 32 is connected to the data fusion module 35, which is used to demodulate the DC sampling signal to obtain a DC measurement signal; The output end of the low-frequency AC processing module 33 is connected to the data fusion module 35, and is used to process the first AC sampling signal to obtain a first AC measurement signal with a frequency less than a first preset frequency; The input end of the high-frequency AC processing module 34 is connected to the Rogowski coil 21, and the output end is connected to the data fusion module 35, and is used to process the second sampling signal output by the Rogowski coil 21 to obtain a second AC measurement signal having a frequency greater than a second preset frequency, where the first preset frequency is equal to the second preset frequency; The data fusion module 35 is configured to fuse the DC measurement signal, the first AC measurement signal, and the second AC measurement signal to obtain a measurement signal corresponding to the current to be measured.

[0030] In this embodiment, please refer to Figure 2 , Figure 2A structural schematic diagram of another current measuring device provided by the present invention; specifically, the signal separation module 31 can separate the first sampling signal output by the fluxgate core 11 through the winding 12, so that the DC sampling signal can be processed by the DC processing module 32, and the low-frequency AC processing module 33 can process the first AC sampling signal, which is beneficial to ensure modulation accuracy.

[0031] Since the current measurement device processes signals of different frequency bands separately through the DC processing module 32, the low-frequency AC processing module 33, and the high-frequency AC processing module 34, the final complete measurement signal is the result of the fusion of signals of different frequency bands. That is, the data fusion module 35 is specifically used to align the phases of the corresponding frequency bands of the received DC measurement signal, the first AC measurement signal, and the second AC measurement signal, and then superimpose them to obtain a measurement signal corresponding to the current to be measured, wherein the frequency of the DC measurement signal can be considered to be 0Hz. In addition, the first preset frequency is equal to the second preset frequency, which can prevent signal aliasing caused by frequency band overlap when the subsequent data fusion module 35 performs multi-signal fusion processing, thereby improving signal processing accuracy and ensuring the continuity of the measurement frequency band.

[0032] It should also be noted that in actual applications, the DC sampling signal is usually not an ideal, pure DC signal, but because the nonlinear structure of the device will superimpose the second harmonic signal. Therefore, the DC processing module 32 can demodulate the DC sampling signal to obtain the core DC measurement signal after removing the second harmonic from the DC sampling signal.

[0033] In some embodiments, the processing module 3 further includes a sampling resistor and a voltage acquisition module; One end of the sampling resistor is grounded, and the other end is connected to the winding 12 and then connected to the input end of the voltage acquisition module; The output end of the voltage acquisition module is connected to the input end of the signal separation module 31 .

[0034] Specifically, the first sampling signal output by the fluxgate core 11 through the winding 12 can be proportionally converted into a first sampling signal with a smaller amplitude through the sampling resistor to meet the sampling signal requirement that can be received by the subsequent signal separation module 31.

[0035] In some embodiments, the low-frequency AC processing module 33 includes a low-frequency data processing module 331 and a low-pass filter 332 connected in sequence; The low-frequency data processing module 331 is used to demodulate the first AC sampling signal to obtain a corresponding first AC intermediate signal; The low-pass filter 332 is configured to process the first AC intermediate signal to output a first AC measurement signal having a frequency lower than its own corresponding first cutoff frequency.

[0036] It should be noted that in actual applications, due to the nonlinear structure of the device, a second harmonic signal will also be superimposed on the first AC sampling signal, that is, the first AC sampling signal is essentially the superposition of its own AC frequency signal and the second harmonic signal. Therefore, the low-frequency data processing module 331 demodulates the first AC sampling signal to obtain a core first AC intermediate signal after removing the second harmonic; and uses the low-pass filter 332 to achieve signal segmentation to obtain and output a first AC measurement signal with a frequency less than the first cutoff frequency corresponding to the low-pass filter 332.

[0037] In some embodiments, the high-frequency AC processing module 34 includes an integration module 341 , a high-frequency data processing module 342 , and a high-pass filter 343 connected in sequence; The integration module 341 is used to integrate the second sampling signal output by the Rogowski coil 21 to obtain a second AC intermediate signal; The high-frequency data processing module 342 is configured to perform noise removal and ripple filtering on the second AC intermediate signal to obtain a third AC intermediate signal. The high-pass filter 343 is used to process the third AC intermediate signal to output a second AC measurement signal having a frequency greater than its own corresponding second cutoff frequency, where the second cutoff frequency is equal to the first cutoff frequency.

[0038] Specifically, the second sampling signal output by the Rogowski coil 21 is essentially the differential of the current to be measured, so an integration module 341 is set to realize signal restoration. The integration module 341 here can be an integration circuit. There is no special limitation on the specific circuit form of the integration circuit here, and it can be flexibly set according to actual needs; considering that the second AC intermediate signal obtained after integration still contains high-frequency noise or residual ripple introduced in the integration process, a high-frequency data processing module 342 is set for denoising and ripple filtering; a high-pass filter 343 is set to realize signal segmentation, and a second AC measurement signal with a frequency greater than the second cutoff frequency corresponding to the high-pass filter is obtained and output.

[0039] The setting of the second cutoff frequency being equal to the first cutoff frequency ensures that when the multi-signal fusion processing is subsequently performed in the data fusion module 35, the frequency bands corresponding to the first AC measurement signal and the second AC measurement signal do not overlap, which is conducive to accurately controlling the measurement bandwidth of the fluxgate core 11 and the winding 12, as well as the Rogowski coil 21, effectively preventing the frequency bands of the final measurement signal from overlapping and avoiding signal distortion.

[0040] In addition, the measurement principle of the current measuring device is further described in detail in combination with the above embodiments: Under ideal conditions, there are pure DC current, low-frequency AC current and high-frequency AC current. When the current to be measured is DC current, the fluxgate mutual inductor formed by the fluxgate core 11 and the winding 12 can achieve effective output, while the Rogowski coil 21 has no effective output because it is based on the principle of electromagnetic induction and has no current change rate (di / dt=0). At this time, the DC processing module 32 in the processing module 3 has output, the low-frequency AC processing module 33 and the high-frequency AC processing module 34 have no output, and the data fusion module 35 only receives the signal output by the DC processing module 32, so it can be directly output without fusion and processing; when the current to be measured is low-frequency AC current, the fluxgate mutual inductor can still output effectively, and when the frequency of the low-frequency AC current to be measured is close to the effective measurement frequency of the Rogowski coil 21, the Rogowski coil 21 has no effective output. The Rogowski coil 21 may have a weak output, but this output will be blocked by the high-pass filter 343. In this case, the system level can assume that the high-frequency AC processing module 34 has no output. At this time, the DC processing module 32 also has no output, and only the low-frequency AC processing module 33 outputs a valid signal. Therefore, the data fusion module 35 directly outputs the processing result of the low-frequency AC processing module 33. When the current to be measured is a high-frequency AC current, the output of the Rogowski coil 21 is valid. Due to the response speed limitation, the fluxgate transformer may produce an attenuated output, but this output will be blocked by the low-pass filter 332. In this case, the system level can assume that the low-frequency AC processing module 33 has no output. At this time, the DC processing module 32 also has no output, and only the high-frequency AC processing module 34 outputs a valid signal. Therefore, the data fusion module 35 directly outputs the processing result of the high-frequency AC processing module 34.

[0041] However, the above is only an ideal situation. In actual applications, the signal components of the current to be measured are very complex and are not composed of components of a single frequency. Low-frequency components and high-frequency components may exist in the current to be measured at the same time. DC components or attenuated DC components may also exist in the AC current. Therefore, the outputs of the fluxgate transformer and the Rogowski coil 21 are both valid, and the DC measurement signal, the first AC measurement signal, and the second AC measurement signal are then aligned in time through the processing module 3 and then fused and output.

[0042] In some embodiments, the current measurement device further includes an upper monitoring module 36 connected to the processing module 3; The processing module 3 is further configured to send the measurement signal to the upper monitoring module 36 .

[0043] Specifically, the data fusion module 35 in the processing module 3 is connected to the upper monitoring module 36, such as Figure 2As shown, by uploading the measurement signal corresponding to the measured current to the upper monitoring module 36, the upper monitoring module 36 can store and / or display the currently detected measurement signal, and can subsequently promptly issue an alarm when an overcurrent condition occurs in the measured current, thereby facilitating technicians to promptly identify and address the fault. Furthermore, the upper monitoring module 36 can be used to query the measured current at different times. It should be noted that the upper monitoring module 36 herein includes, but is not limited to, a host computer and is not specifically limited to this.

[0044] In some embodiments, the current measurement device further includes a correction wire 41 and a correction source module 42; The correction wire 41 is used to pass through the center of the fluxgate core 11 and the Rogowski coil 21 and then be connected to the correction source module 42; The correction source module 42 is used to output a standard current, so as to determine the current measurement accuracy of the current measurement device according to the standard current and the corresponding correction measurement signal output by the processing module 3 .

[0045] In this embodiment, the correction wire 41 is a detachable correction wire, and the correction source module 42 can be a standard current source; Figure 1 As shown, a schematic diagram of the setting is given in which the correction wire 41 is passed through the center of the fluxgate core 11 and the Rogowski coil 21 and then connected to the correction source module 42. It can be understood that the correction wire 41 and the correction source module 42 are used to calibrate the current measuring device before measuring the current to be measured. In actual application, the wire through which the current to be measured flows is passed through the center of the fluxgate core 11 and the Rogowski coil 21 to achieve the measurement of the current to be measured without using the correction wire 41 and the correction source module 42.

[0046] Specifically, the calibration source module 42 outputs a known, standard current, which can be either a direct current or an alternating current, without particular limitation herein. Therefore, after the standard current flows through the calibration wire 41, the current measurement accuracy of the current measuring device can be determined based on the standard current and the corresponding measurement signal output by the processing module 3, thereby determining whether the measurement accuracy meets the preset requirements and can be used to measure the current to be measured. It is understood that when the preset requirements are not met, a technician can analyze the cause of the measurement accuracy error to adjust the current measuring device. This is not particularly limited herein, and flexible analysis and adjustment can be performed based on the actual application.

[0047] It can be seen that the above setting is conducive to on-site self-calibration of the current measuring device before measuring the current to be measured on-site, and then on-site measurement is carried out after verifying that its measurement accuracy meets the preset requirements, thereby ensuring the accuracy and reliability of on-site measurement of the current to be measured, and facilitating use in complex environments.

[0048] In some embodiments, the current measuring device further includes a shielding cover 5; The Rogowski coil 21 and the fluxgate core 11 wound with the winding 12 are both disposed in the shielding case 5 .

[0049] Specifically, the Rogowski coil 21 and the fluxgate core 11 wound with the winding 12 can be fixedly arranged in the shielding cover 5 on the basis of satisfying the above-mentioned structural setting. The setting of the shielding cover 5 makes the current measuring device have strong anti-interference ability, which is conducive to improving the accuracy and reliability of the measurement signal, and is particularly suitable for application in the complex environment of the substation site.

[0050] In addition, the shielding cover 5 is essentially a circular ring structure, such as Figure 1 As shown, the diameter of the inner circle 51 is smaller than the preset threshold value, so that the inner circle 51 is as small as possible so that the wire through which the current to be measured flows can pass through. Figure 1 In order to clearly illustrate the structure of the shielding cover 5, the diameter of the inner circle 51 is larger).

[0051] The present invention also provides a circuit monitoring system, comprising the current measuring device as described above.

[0052] For an introduction to the circuit monitoring system provided in this application, please refer to the above-mentioned embodiment of the current measuring device, which will not be repeated here.

[0053] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. Relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements limited by the sentence "comprising a" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0054] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A current measuring device, characterized in that: The device comprises a fluxgate core, a winding, a Rogowski coil, a magnetization module, and a processing module; the fluxgate core and the Rogowski coil are both annular structures, the fluxgate core and the Rogowski coil are arranged parallel to each other along the axis and separated by a preset distance, and the central axis of the fluxgate core is coaxial with the central axis of the Rogowski coil; The magnetization module is connected to the winding, the winding is wound around the fluxgate core and is also connected to the processing module after being wound, and the magnetization module is used to magnetize the fluxgate core so that the magnetization intensity of the fluxgate core reaches a preset maximum intensity value; The processing module is also connected to the Rogowski coil and is used to fuse the first sampling signal output by the fluxgate core through the winding and the second sampling signal output by the Rogowski coil when the conductor through which the current to be measured flows passes through the center of the fluxgate core and the Rogowski coil, so as to obtain a measurement signal corresponding to the current to be measured.

2. The current measuring device according to claim 1, wherein 5mm≤the preset distance≤3cm.

3. The current measuring device according to claim 1, wherein The processing module includes a signal separation module, a DC processing module, a low-frequency AC processing module, a high-frequency AC processing module and a data fusion module; The input end of the signal separation module is connected to the winding, the first output end is connected to the input end of the DC processing module, and the second output end is connected to the input end of the low-frequency AC processing module, and is used to perform signal separation on the first sampling signal output by the fluxgate core through the winding, so as to output the separated DC sampling signal to the DC processing module, and output the separated first AC sampling signal to the low-frequency AC processing module; The output end of the DC processing module is connected to the data fusion module, and is used to demodulate the DC sampling signal to obtain a DC measurement signal; The output end of the low-frequency AC processing module is connected to the data fusion module, and is used to process the first AC sampling signal to obtain a first AC measurement signal with a frequency less than a first preset frequency; The input end of the high-frequency AC processing module is connected to the Rogowski coil, and the output end is connected to the data fusion module, and is used to process the second sampling signal output by the Rogowski coil to obtain a second AC measurement signal with a frequency greater than a second preset frequency, where the first preset frequency is equal to the second preset frequency; The data fusion module is used to fuse the DC measurement signal, the first AC measurement signal, and the second AC measurement signal to obtain a measurement signal corresponding to the current to be measured.

4. The current measuring device according to claim 3, wherein: The processing module also includes a sampling resistor and a voltage acquisition module; One end of the sampling resistor is grounded, and the other end is connected to the winding and then connected to the input end of the voltage acquisition module; The output end of the voltage acquisition module is connected to the input end of the signal separation module.

5. The current measuring device according to claim 3, wherein: The low-frequency AC processing module includes a low-frequency data processing module and a low-pass filter connected in sequence; The low-frequency data processing module is used to demodulate the first AC sampling signal to obtain a corresponding first AC intermediate signal; The low-pass filter is used to process the first AC intermediate signal to output a first AC measurement signal having a frequency lower than its own corresponding first cut-off frequency.

6. The current measuring device according to claim 5, characterized in that The high-frequency AC processing module includes an integration module, a high-frequency data processing module and a high-pass filter connected in sequence; The integration module is used to integrate the second sampling signal output by the Rogowski coil to obtain a second AC intermediate signal; The high-frequency data processing module is used to perform noise removal and ripple filtering on the second AC intermediate signal to obtain a third AC intermediate signal; The high-pass filter is used to process the third AC intermediate signal to output a second AC measurement signal having a frequency greater than its own corresponding second cutoff frequency, where the second cutoff frequency is equal to the first cutoff frequency.

7. The current measuring device according to claim 1, wherein The current measuring device further comprises an upper monitoring module connected to the processing module; The processing module is further configured to send the measurement signal to the upper monitoring module.

8. The current measuring device according to claim 1, wherein The current measuring device also includes a correction wire and a correction source module; The correction wire is used to pass through the center of the fluxgate core and the Rogowski coil and then be connected to the correction source module; The correction source module is used to output a standard current, so as to determine the current measurement accuracy of the current measurement device according to the standard current and the corresponding correction measurement signal output by the processing module.

9. The current measuring device according to any one of claims 1 to 8, characterized in that: The current measuring device further includes a shielding cover; The Rogowski coil and the fluxgate core wound with the winding are both arranged in the shielding cover.

10. A circuit monitoring system, characterized in that: The device comprises a current measuring device according to any one of claims 1 to 9.

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