Current sensing device

Abstract

The invention belongs to the technical field of electronic sensing, and particularly discloses a current sensing device. The current sensing device comprises a first PCB type Rogowski coil, a second PCB type Rogowski coil and a third Rogowski coil, wherein the first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals to form a tubular structure, and the third Rogowski coil is uniformly wound on the tubular structure; and the first PCB type Rogowski coil and the second PCB type Rogowski coil are connected in series according to a stacking sequence and then are connected in series with the third Rogowski coil. The third Rogowski coil and the PCB type coil are combined, and the PCB type coil serves as a winding framework of the third Rogowski coil, so that the induction signal of the Rogowski coil can be increased to the maximum extent in a limited space size, and the sensitivity of current sensing is improved.

Description

Technical Field

[0001] The present application belongs to the field of electronic sensor technology, and more specifically, relates to a current sensor device. Background Art

[0002] About 50% of the faults in the power system come from insulation faults. During the long-term energized operation, the insulation equipment is affected by high-voltage electric fields, chemical corrosion, mechanical stress and environmental factors, and its performance gradually declines, and the insulation strength gradually decreases. The deterioration of insulation performance will cause an increase in leakage current. The increase in leakage current causes the temperature of the insulation equipment to rise, resulting in active power loss and thermal collapse. In severe cases, it will cause damage or explosion and fire, trigger insulation breakdown, cause equipment damage, large-scale power outages, and bring huge losses. The insulation performance of the equipment is generally evaluated by accurately monitoring the leakage current size and phase angle of the equipment and deriving the corresponding parameters. The leakage current is usually very weak. The Rogowski coil has the advantages of good linearity and high measurement accuracy, especially isolation and insulation from the measured signal. Therefore, it is widely used in small current detection in high voltage environments.

[0003] There are two main types of Rogowski coils as non-contact current sensors, such as Figure 1 As shown in the figure: one is a traditional Rogowski coil, whose enameled wire is evenly wound on a hard or flexible non-magnetic frame; the other is a PCB (Printed Circuit Board) type Rogowski coil, which is a Rogowski coil printed on a PCB. The mutual inductance between the Rogowski coil and the measured current conductor is the most critical parameter that determines the measurement accuracy and sensitivity. However, because the two Rogowski coils do not contain a magnetic core and have a small mutual inductance, the induced voltage is very weak when detecting the current signal, so it is impossible to detect a very small current. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a current sensing device, which aims to solve the technical problem that the existing Rogowski coil cannot detect tiny currents.

[0005] To achieve the above-mentioned purpose, in a first aspect, the present application provides a current sensing device, including: a first PCB type Rogowski coil, a second PCB type Rogowski coil and a third Rogowski coil; wherein the first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals to form a tubular structure, and the third Rogowski coil is evenly wound on the tubular structure; the first PCB type Rogowski coil and the second PCB type Rogowski coil are connected in series in a stacking order and then connected in series with the third Rogowski coil. Preferably, the number of the first PCB type Rogowski coils and the number of the second PCB type Rogowski coils are equal.

[0006] Preferably, the winding directions of the first PCB type Rogowski coil and the second PCB type Rogowski coil are opposite.

[0007] Preferably, the winding positions of the first PCB type Rogowski coil and the second PCB type Rogowski coil are mirror images of each other.

[0008] Preferably, in the tubular structure, the deflection angles of the first PCB-type Rogowski coil and the second PCB-type Rogowski coil adjacent to each other vertically are different.

[0009] Preferably, the side of the first PCB type Rogowski coil has positive terminals and negative terminals of a half-hole process, and the side of the second PCB type Rogowski coil has positive terminals and negative terminals of a half-hole process; in the tubular structure, the positive / negative terminals of the upper layer and the negative / positive terminals of the lower layer are aligned and connected.

[0010] Preferably, the third Rogowski coil is wound in an interval manner of one forward winding and one reverse winding.

[0011] Preferably, it further comprises a winding fixing unit, which is located outside the tubular structure and together with the tubular structure constitutes a winding skeleton, and the winding skeleton is used for being evenly wound by the third Rogowski coil.

[0012] Preferably, the winding fixing unit has uniform comb-shaped slots, and the comb-shaped slots are used to limit the winding position of the coil.

[0013] Preferably, a shielding cover is further included, wherein the first PCB type Rogowski coil, the second PCB type Rogowski coil and the third Rogowski coil are located in the shielding cover.

[0014] Preferably, the shielding cover is Permalloy.

[0015] Preferably, it also includes a signal processing unit; after being connected in series, one end of the first PCB type Rogowski coil, the second PCB type Rogowski coil and the third Rogowski coil is connected to the first input end of the signal processing unit, and the other end is connected to the second input end of the signal processing unit.

[0016] Preferably, the signal processing unit is used to collect the sensing signal, amplify and convert the sensing signal into analog-to-digital, perform signal integration operation in the digital domain, restore the signal phase, and accurately measure the current signal.

[0017] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: (1) The present application adopts two PCB type Rogowski coils stacked at intervals to form a tubular structure, and a traditional third Rogowski coil is wound with the tubular structure as a skeleton, thereby forming a comprehensive Rogowski coil. The comprehensive Rogowski coil of the present application can improve the mutual inductance coefficient of the coil in a limited space, thereby realizing the precise measurement of small current signals.

[0018] (2) In the present application, positive and negative terminals of a half-hole process are designed on the edge of the PCB type Rogowski coil, and the upper and lower PCB type Rogowski coils are connected in series through the positive and negative terminals. This can omit connectors, reduce the risk of failure at the connection point, and reduce the spacing between the upper and lower PCB type Rogowski coils. More PCB type Rogowski coils can be accommodated in the same space, effectively improving the mutual inductance coefficient of the device.

[0019] (3) In the present application, the first PCB type Rogowski coil and the second PCB type Rogowski coil have opposite winding directions, and their winding positions are mirror images of each other. After stacking, the adjacent upper and lower layers are deflected and misaligned, thereby reducing axial electromagnetic interference by mirroring each other, and the deflection and misalignment of the upper and lower layers reduce the capacitive coupling between the single PCB boards, thereby reducing self-interference.

[0020] (4) The present application provides a winding fixing unit with comb-shaped slots, which can effectively improve the winding process of the third Rogowski coil and ensure the uniformity and consistency of the winding.

[0021] (5) The present application is provided with a shielding cover made of Bomal alloy, which can help reduce the interference of electric and magnetic fields on the Rogowski coil in the present device, thereby improving the sensing measurement accuracy of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the Rogowski coil proposed in the background technology of this application.

[0023] Figure 2 is a schematic diagram of a current sensing device provided in an embodiment of the present application.

[0024] Figure 3 It is a schematic diagram of the winding of the first PCB type Rogowski coil and the second PCB type Rogowski coil provided in the embodiment of the present application.

[0025] Figure 4 It is a schematic diagram of a first PCB type Rogowski coil and a second PCB type Rogowski coil provided in an embodiment of the present application, which are stacked in series with an interval.

[0026] Figure 5 It is a schematic diagram of the appearance of the winding fixing unit provided in an embodiment of the present application.

[0027] Figure 6 It is a schematic diagram of the shielding cover provided in an embodiment of the present application.

[0028] Figure 7 This is a flow chart of installation and measurement of a current sensor device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] The term “ / ” in the present application describes an “or” relationship, for example, positive / negative means: positive or negative. The terms "first" and "second" in the specification and claims of this application are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first PCB-type Rogowski coil and a second PCB-type Rogowski coil are used to distinguish different PCB-type Rogowski coils rather than to describe a specific order of the PCB-type Rogowski coils.

[0031] In this application, the words "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0032] In the description of the present application, unless otherwise specified, “plurality” means two or more than two. For example, a plurality of Rogowski coils means two or more than two Rogowski coils, etc.; a plurality of elements means two or more than two elements, etc.

[0033] The technical solution of the present application is further described below in conjunction with the embodiments of the present application.

[0034] Embodiment 1: The embodiments of the present application introduce the structural composition, installation and measurement process of a current sensor device, thereby further illustrating the technical solution of the present application.

[0035] like Figure 2 As shown, a current sensing device in an embodiment of the present application includes: 3 first PCB type Rogowski coils, 3 second PCB type Rogowski coils and 1 third Rogowski coil; wherein the first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals to form a tubular structure, that is, the first PCB type Rogowski coil of version A and the second PCB type Rogowski coil of version B in the figure are stacked at intervals. In this embodiment, a total of 3 first PCB type Rogowski coils and 3 second PCB type Rogowski coils are stacked at intervals to form a tubular structure.

[0036] The present application does not limit the number of the first PCB type Rogowski coil and the second PCB type Rogowski coil, and a plurality of first PCB type Rogowski coils and a plurality of second PCB type Rogowski coils may be stacked to form a tubular structure. Alternatively, a first PCB type Rogowski coil and a second PCB type Rogowski coil may be stacked to form a tubular structure, and both options belong to the technical solution of the present application.

[0037] When the number of the first PCB type Rogowski coil and the number of the second PCB type Rogowski coil are equal, the effect of the present application is optimal.

[0038] In this embodiment, the third Rogowski coil is evenly wound on the tubular structure; the first PCB type Rogowski coil and the second PCB type Rogowski coil are connected in series in a stacking order and then connected in series with the third Rogowski coil. The winding method of the first PCB type Rogowski coil and the second PCB type Rogowski coil in this embodiment is as follows: Figure 3 As shown, Figure 3 The first PCB type Rogowski coil on the left is wound clockwise, and the second PCB type Rogowski coil on the right is wound counterclockwise, and their winding directions are opposite. In addition, the winding positions of the first PCB type Rogowski coil and the second PCB type Rogowski coil are mirror images of each other. This can reduce the magnetic field interference perpendicular to the plane magnetic field, that is, the axial direction.

[0039] When the first PCB-type Rogowski coil and the second PCB-type Rogowski coil are stacked at intervals, the deflection angles of the first PCB-type Rogowski coil and the second PCB-type Rogowski coil adjacent to each other are different. Figure 3 As shown in the figure, the deflection angle of the first PCB type Rogowski coil on the left is smaller than the deflection angle of the second PCB type Rogowski coil on the right. The deflection misalignment of the upper and lower layers can effectively reduce the capacitive coupling between single PCB boards and reduce self-interference.

[0040] At the same time, the positive terminal and negative terminal of the half-hole process are designed on the side of the first PCB type Rogowski coil, and the positive terminal and negative terminal of the half-hole process are also designed on the side of the second PCB type Rogowski coil. The positive terminal and the negative terminal are respectively connected to the two ends of the PCB type Rogowski coil.

[0041] like Figure 4 As shown, when the first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals, the positive / negative terminals of the upper layer and the negative / positive terminals of the lower layer are aligned and connected, thereby connecting the upper PCB type Rogowski coil and the lower PCB type Rogowski coil in series. In the embodiment of the present application, the upper and lower layers are connected in series through the positive and negative terminals of the half-hole process, thereby omitting the connector, reducing the risk of failure, and reducing the interval between the first PCB type Rogowski coil and the second PCB type Rogowski coil after stacking, so that more PCB type Rogowski coils can be accommodated in the same space, effectively improving the mutual inductance coefficient of the device.

[0042] The first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals to form a tubular structure. Figure 5 As shown, in this embodiment, a hollow barrel-shaped winding fixing unit is designed to accommodate the tubular structure, and the winding fixing unit and the internal tubular structure together serve as a winding skeleton of the third Rogowski coil, and the third Rogowski coil is evenly wound on the winding skeleton.

[0043] The winding fixing unit has uniform comb-shaped slots, and the third Rogowski coil is wound along the uniform comb-shaped slots, so that the uniformity and consistency of the winding can be ensured.

[0044] The third Rogowski coil is wound in an interval manner of one forward winding and one reverse winding, thereby reducing axial magnetic field interference.

[0045] like Figure 6 The shielding cover provided in the embodiment of the present application is shown, and the first PCB type Rogowski coil, the second PCB type Rogowski coil and the third Rogowski coil are placed in the shielding cover after being connected in series as described above. The shielding cover can reduce the interference of the electric field and the magnetic field on the coil in the device, thereby improving the sensing accuracy of the present application.

[0046] The embodiment of the present application also includes a signal processing unit; after being connected in series, one end of the first PCB type Rogowski coil, the second PCB type Rogowski coil and the third Rogowski coil is connected to the first input end of the signal processing unit, and the other end is connected to the second input end of the signal processing unit.

[0047] The signal processing unit is used to collect the sensing signal, amplify the sensing signal and convert it into analog-to-digital form, then perform signal integration in the digital domain, restore the signal phase, and accurately measure the current signal.

[0048] Embodiment 2: The embodiment of the present application introduces the installation and measurement process of a current sensor device. This further illustrates the technical solution of the present application. Figure 7 As shown, the specific steps include: (1) stacking a plurality of first PCB-type Rogowski coils and a plurality of second PCB-type Rogowski coils at intervals to form a tubular structure; (2) In the tubular structure, the negative electrode / positive electrode of the upper PCB type Rogowski coil is connected to the positive electrode / negative electrode of the lower PCB type Rogowski coil, thereby the plurality of first PCB type Rogowski coils and the plurality of second PCB type Rogowski coils in the tubular structure are sequentially connected in series in a stacking order, such as Figure 4 As shown; (3) placing the stacked and serially connected tubular structure into a winding fixing unit; (4) Winding the enameled wire of the third Rogowski coil along the comb-shaped slots on the winding fixing unit, using an interval winding method of one forward winding and one reverse winding for uniform winding; (5) After the third Rogowski coil is wound, the third Rogowski coil is connected in series to the tail end of the tubular structure; (6) Place the first PCB-type Rogowski coil, the second PCB-type Rogowski coil and the third Rogowski coil connected in series in sequence into a shielding box, and lead out the two ends of the series-connected coils; (7) The two ends of the series coil are connected to a signal processing unit, which collects the induced signal, amplifies the signal and performs analog-to-digital conversion, and then integrates the signal in the digital domain to accurately measure the current signal.

[0049] The method of the present application can realize the combination of two types of Rogowski coils, PCB type Rogowski coil and traditional Rogowski coil, in a limited space, thereby improving the mutual inductance coefficient in a limited space, thereby realizing the precise measurement of tiny current signals.

[0050] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0051] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0052] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0053] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A current sensing device, characterized in that: include: a first PCB type Rogowski coil, a second PCB type Rogowski coil and a third Rogowski coil; wherein the first PCB type Rogowski coil and the second PCB type Rogowski coil are stacked at intervals to form a tubular structure, and the third Rogowski coil is evenly wound on the tubular structure; the first PCB type Rogowski coil and the second PCB type Rogowski coil are connected in series in a stacking order and then connected in series with the third Rogowski coil.

2. The current sensor device according to claim 1, characterized in that: The number of the first PCB type Rogowski coils and the number of the second PCB type Rogowski coils are equal.

3. The current sensor device according to claim 1, characterized in that: The winding directions of the first PCB type Rogowski coil and the second PCB type Rogowski coil are opposite.

4. The current sensor device according to claim 1, characterized in that: The winding positions of the first PCB type Rogowski coil and the second PCB type Rogowski coil are mirror images of each other.

5. The current sensing device according to claim 1, characterized in that: In the tubular structure, the deflection angles of the first PCB-type Rogowski coil and the second PCB-type Rogowski coil adjacent to each other are different.

6. The current sensing device according to claim 1, characterized in that: The side of the first PCB type Rogowski coil has positive terminals and negative terminals of a half-hole process, and the side of the second PCB type Rogowski coil has positive terminals and negative terminals of a half-hole process; in the tubular structure, the positive / negative terminals of the upper layer and the negative / positive terminals of the lower layer are aligned and connected.

7. The current sensing device according to claim 1, characterized in that: The third Rogowski coil is wound in an interval manner of one forward winding and one reverse winding.

8. The current sensing device according to claim 1, characterized in that: It also includes a winding fixing unit, which is located outside the tubular structure and together with the tubular structure forms a winding skeleton, and the winding skeleton is used for being evenly wound by the third Rogowski coil.

9. The current sensing device according to claim 8, characterized in that: The winding fixing unit is provided with uniform comb-shaped slots, and the comb-shaped slots are used to limit the winding position of the coil.

10. The current sensor device according to claim 1, characterized in that: It also includes a shielding cover, in which the first PCB type Rogowski coil, the second PCB type Rogowski coil and the third Rogowski coil are located.

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