High-sensitivity high-frequency very-high-frequency current sensor with extremely small number of turns wound on single side

Abstract

The utility model discloses a high-sensitivity high-frequency very-high-frequency current sensor with extremely few turns wound on one side, and belongs to the technical field of power electronics. Comprising a high-permeability magnetic core, a single-side winding with extremely few turns and an aluminum shielding box wrapping the magnetic core. The magnetic core is made of soft magnetic materials such as ferrite, has high magnetic conductivity and is used for achieving electromagnetic coupling of the current-carrying cable and winding. A single-side winding with extremely few turns is wound on one side of the magnetic core, the number of turns is 1 or 2, and high sensitivity and large bandwidth of transfer impedance can be achieved at the same time. The aluminum shielding box wraps the magnetic core and is used for shielding external electromagnetic interference. The sensor is compact in structure and high in linearity, has a large bandwidth of 1MHz-100MHz, and can accurately measure pulse current signals generated by partial discharge of the cable. The device has the advantages of simple structure, high sensitivity, large bandwidth, strong anti-interference capability and the like, and is suitable for cable partial discharge detection and other occasions needing to measure high-frequency or very-high-frequency pulse current signals.

Description

Technical Field

[0001] This utility model belongs to the field of power electronics technology, and in particular relates to a highly sensitive high-frequency and very high-frequency current sensor with a very small number of turns wound on one side for partial discharge detection of cables. Background Technology

[0002] With the development of power systems, high-voltage cables have become common power transmission tools in both civilian and military fields. When high-voltage cables are affected by impurities and experience partial discharge, a large pulse current is generated. Accurate determination of this large pulse current is also necessary for the electroplating process control of special components in large equipment and the testing of power electronic devices to ensure stable manufacturing processes and product reliability. Therefore, various current sensor schemes for partial discharge detection have been proposed to ensure that their sensitivity response range and operating frequency band meet the requirements of various applications.

[0003] Current sensors are mainly used to measure periodic high-frequency currents or rapidly fluctuating pulse current signals, and they have wide applications in many fields such as power grid monitoring, scientific research, and even national defense. The high-frequency current method is a common method for detecting partial discharge in cables. By installing a high-frequency current sensor on the cable grounding wire or the cable body, the signal generated in the high-frequency pulse current path can be coupled to detect the pulse current generated by partial discharge in the cable.

[0004] Currently, the Rogowski coils commonly used in current sensors consist of fine copper wire evenly wound on a magnetic core, employing a rewinding structure. However, they suffer from drawbacks such as narrow operating bandwidth and low transfer impedance sensitivity. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems mentioned in the background section by providing a highly sensitive high-frequency and very high-frequency current sensor with a single-sided winding of very few turns. It is a high-sensitivity, wide-bandwidth current sensor designed for partial discharge detection in cables. This sensor employs a single-sided winding technique with very few turns, aiming to improve detection efficiency and accuracy, and is suitable for scenarios such as partial discharge monitoring of high-voltage cables, electroplating process control of large equipment, and testing of power electronic devices.

[0006] To achieve the above-mentioned technical objectives, the technical solution of this utility model is as follows:

[0007] A high-sensitivity high-frequency and very high-frequency current sensor with a single-sided winding of very few turns includes a high-permeability magnetic core, a single-sided winding of very few turns, and an aluminum shielding box.

[0008] The high permeability magnetic core is used to achieve electromagnetic coupling between the current-carrying cable and the winding; the shape and size of the high permeability magnetic core are set according to actual needs to ensure the best electromagnetic coupling effect.

[0009] The single-sided minimal-turn winding is wound around one side of the surface of the high-permeability magnetic core, with 1 or 2 turns. The single-sided minimal-turn winding is made of a material with good conductivity and is used to sense the magnetic field change generated by the current-carrying cable under test and generate a corresponding electrical signal, thereby improving the transfer impedance sensitivity of the sensor and ensuring a large bandwidth characteristic.

[0010] The aluminum shielding box is wrapped around the magnetic core and the winding to shield external electromagnetic interference and improve the sensor's anti-interference capability. The front end of the aluminum shielding box has an opening for leading out a connection port of a single-sided winding with very few turns. An auxiliary air gap is provided between the inner side of the aluminum shielding box and the magnetic core to optimize the magnetic field distribution and improve the sensor's performance.

[0011] The aluminum shielding box and magnetic core are cut in half along their circumference to form two semi-ring structures. In application, the two semi-ring structures are clamped together to form a complete ring structure, and the current-carrying cable under test passes perpendicularly through the central hole of the ring structure; this facilitates installation and disassembly while ensuring the stability and reliability of the sensor.

[0012] The sensor has a large bandwidth of 1MHz to 100MHz, a transfer impedance sensitivity of not less than 13Ω, and is used to accurately measure the pulse current signal generated by partial discharge of the cable. It also has good linearity and dynamic range.

[0013] Furthermore, the high permeability magnetic core is made of ferrite material with a relative permittivity of 12, a permeability of 20000, and a conductivity of 0.01, or other soft magnetic materials with high permeability and similar properties.

[0014] Furthermore, the high permeability magnetic core is ring-shaped or approximately ring-shaped and has a central hole through which the current-carrying cable under test can pass perpendicularly.

[0015] Furthermore, the winding material is made of copper or silver, or other metal materials with good conductivity and suitable for high-frequency applications;

[0016] Furthermore, the aluminum shielding box can be replaced with other metal materials with good conductivity and shielding effect. The aluminum shielding box shields against interference from external magnetic fields and provides insulating support for the wound magnetic core.

[0017] Furthermore, the magnetic core has an inner radius of 39mm, an outer radius of 64mm, and a height of 25mm; the gap between the shielding box and the outer surface of the magnetic core is 2mm, the width of the auxiliary air gap is 0.1mm, the gap between the upper surface of the magnetic core and the shielding box is 2mm, and the gap between the single-sided winding and the magnetic core is 0.25mm; the side thickness of the shielding box is 7mm, and the thickness of the top and bottom sides is 5mm; or the above structural dimensions can be appropriately adjusted according to actual needs.

[0018] The sensor described in this invention is used in cable partial discharge detection scenarios and can accurately measure the partial discharge pulse current signal generated by the cable when it is affected by impurities. At the same time, it can also be applied to other occasions that require the measurement of high frequency or very high frequency pulse current signals.

[0019] Compared with existing technologies, this structure has the following advantages:

[0020] 1. This invention features a single-sided winding design with minimal turns, resulting in higher sensor linearity. The sensor can more accurately detect pulse currents generated by partial discharge in cables, thus improving detection sensitivity.

[0021] 2. The sensor's operating bandwidth reaches 1MHz-100MHz, meeting current measurement requirements across different frequency ranges. It can be widely used in cable partial discharge detection scenarios. It achieves high-sensitivity, wide-bandwidth sensing of partial discharge current within the high-frequency and very-high-frequency bands exceeding 1MHz to 100MHz.

[0022] 3. The aluminum shielding box effectively shields external electromagnetic interference, ensuring stable operation of the sensor in complex environments.

[0023] 4. The ring structure of this utility model is easy to install and disassemble, and is suitable for various cables and wires.

[0024] 5. This invention has high sensitivity and can effectively detect pulse currents caused by partial discharge. It is of great significance to power electronics technology. Attached Figure Description

[0025] Figure 1 This is a three-dimensional schematic diagram of the structural composition of an embodiment of the present utility model.

[0026] Figure 2 This is a top view of the structural dimensions of an embodiment of the present utility model.

[0027] Figure 3 This is a left-side view of the structural dimensions of an embodiment of this utility model.

[0028] Figure 4 This is a front view schematic diagram of the structural dimensions of an embodiment of this utility model.

[0029] Figure 5 The transfer impedance (sensitivity) for embodiments of this utility model is 1MHz to 100MHz.

[0030] Figure 6 The output current of this utility model embodiment is the result of a very small number of turns of the winding being induced by a changing magnetic field. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0032] See Figure 1 The present invention discloses a high-frequency and very high-frequency current sensor structure, comprising a ferrite core 1, a coil 2 with a very small number of turns wound around one side of the core, an aluminum shielding box 3, and a current-carrying conductor 4 to be measured. The current-carrying conductor 4 passes perpendicularly through the center of the ferrite core 1, forming electromagnetic coupling. The ring structure is divided into front and rear parts, with an auxiliary air gap between them.

[0033] See Figures 2-4 The following is a three-view drawing of the structure of this utility model. The structural parameters of the embodiments of this utility model are shown in Table 1.

[0034] Table 1

[0035]

[0036] In this embodiment, the magnetic core is made of ferrite material with a relative permittivity of 12, a permeability of 20000, and a conductivity of 0.01; the single-sided winding material is copper; and the shielding box is an aluminum structure.

[0037] This sensor can also be connected to a signal processing circuit and / or a host computer to realize real-time processing and analysis of measurement data, determine whether there is partial discharge in the cable, and determine the location and intensity of the discharge.

[0038] The method of using this sensor can be found as follows:

[0039] (a) Install the sensor: Install the sensor on the grounding wire or the cable body of the cable under test, and ensure that the relative position between the sensor and the cable is stable;

[0040] (b) Connection circuit: Connect the output port of the sensor to the signal processing circuit and / or the host computer in order to receive and process the electrical signal output by the sensor;

[0041] (c) Applying excitation: Applying a certain voltage or current excitation to the cable to simulate the partial discharge phenomenon;

[0042] (d) Data acquisition: Acquire pulse current signals generated by partial discharge of the cable through sensors and signal processing circuits;

[0043] (e) Data analysis: The collected data is processed and analyzed to determine whether there is partial discharge in the cable and to determine the location and intensity of the discharge.

[0044] Figure 5 This diagram illustrates the variation of the transfer impedance (i.e., sensitivity) of the sensor according to an embodiment of this invention within a frequency range of 1MHz to 100MHz. The X-axis represents frequency, and the Y-axis represents the transfer impedance of the sensor. Figure 5 It can be seen that, within the range of 1MHz to 100MHz, the transfer impedance, i.e. sensitivity, of this novel sensor reaches over 13Ω.

[0045] Figure 6 This invention demonstrates the output current of a sensor with a very small number of turns induced by a changing magnetic field, as shown in this embodiment. Figure 6 It can be seen that the current output on a single-sided winding is basically stable within the operating frequency band of this sensor.

[0046] The above embodiments are preferred embodiments of this utility model, but the embodiments of this utility model are not limited to the described embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this utility model should be considered equivalent substitutions and are included within the protection scope of this utility model. The basic principles, main features, and advantages of this utility model have been shown and described above. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims.

Claims

1. A highly sensitive high-frequency and very high-frequency current sensor with a very small number of turns wound on one side, characterized in that... Its operating frequency is 1 to 100 MHz, and it is used to measure the pulse current signal generated by partial discharge of cable. The sensor includes a high permeability magnetic core, a single-sided winding with very few turns, and an aluminum shielding box. The high permeability magnetic core is used to achieve electromagnetic coupling between the current-carrying cable and the winding. The single-sided minimal-turn winding is wound around one side of the surface of the high-permeability magnetic core, with 1 or 2 turns. The single-sided minimal-turn winding is used to sense the magnetic field change generated by the current-carrying cable under test and generate a corresponding electrical signal, thereby improving the transfer impedance sensitivity of the sensor and ensuring a large bandwidth characteristic. The aluminum shielding box is wrapped around the magnetic core and the winding to shield external electromagnetic interference and improve the sensor's anti-interference capability. The front end of the aluminum shielding box has an opening for leading out a connection port of a single-sided winding with very few turns. An auxiliary air gap is provided between the inner side of the aluminum shielding box and the magnetic core to optimize the magnetic field distribution and improve the sensor's performance.

2. The high-sensitivity high-frequency and very high-frequency current sensor with a very small number of turns wound on one side as described in claim 1, characterized in that... The relative permeability value of the high permeability core is greater than 2000.

3. The high-sensitivity high-frequency and very high-frequency current sensor with a very small number of turns wound on one side as described in claim 1, characterized in that... The high permeability magnetic core is ring-shaped or approximately ring-shaped and has a central hole through which the current-carrying cable under test passes perpendicularly.

4. The high-sensitivity high-frequency and very high-frequency current sensor with a very small number of turns wound on one side as described in claim 1, characterized in that... The aluminum shielding box and magnetic core are cut in half along their circumference to form two semi-ring structures. In application, the two semi-ring structures are clamped together to form a complete ring structure, and the current-carrying cable under test passes perpendicularly through the central hole of the ring structure; this facilitates installation and disassembly while ensuring the stability and reliability of the sensor.

5. The high-sensitivity high-frequency and very high-frequency current sensor with a very small number of turns wound on one side as described in claim 1, characterized in that... The winding material of the single-sided, minimal-turn winding is made of copper or silver.

6. The high-sensitivity high-frequency and very high-frequency current sensor with a very small number of turns wound on one side as described in claim 1, characterized in that... The aluminum shielding box shields against interference from external magnetic fields and provides insulating support for the wound magnetic core.

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