Vertical magnetic field interference resistant inductor and electric power meter thereof

Abstract

The invention relates to a vertical magnetic field interference resistant inductor which comprises a Rogowski coil and a vertical magnetic field counteracting coil located on one side of the Rogowski coil and connected with the Rogowski coil, the Rogowski coil comprises a plurality of hollow coils connected end to end, and the wire diameter, the number of turns, the number of layers, the inner diameter and the outer diameter of each hollow coil are consistent. The number of the hollow coils is not less than 4 and is an even number, the hollow coils are used for being symmetrically distributed on the same horizontal plane with a circle as the center, and output ends are arranged on the Rogowski coil and the vertical magnetic field counteracting coil. Therefore, the technical problem that the current common Rogowski coil is easy to be interfered by an external power frequency electromagnetic field when being used for small current detection, so that the actual current cannot be normally reflected by a large measurement error is solved, and the application limitation of the current Rogowski coil is broken through.

Description

Technical Field

[0001] The present invention relates to an anti-vertical magnetic field interference sensor and an electric power meter used in electric power instruments, in particular to an anti-vertical magnetic field interference sensor and an electric power meter suitable for the field of electric energy transmission. Background Art

[0002] In the development of smart grid in China, electronic transformer is one of the key components of primary equipment. At present, the method used for AC current detection is mainly current transformer.

[0003] There are two main types of current transformers. One is the iron core coil transformer, which is made into different sizes according to the rated current. The disadvantages are large size and high cost. The iron core has magnetic saturation and nonlinearity, so the current measurement range is narrow. It is commonly used for 0.1In to 2In (rated current).

[0004] Another type of current sensor is the Rogowski coil. Also known as an air-core mutual inductor or magnetic potential meter, the Rogowski coil is widely used for measuring high currents. A Rogowski coil is a coil uniformly wound around a non-magnetic frame and placed around a conductor to measure the current flowing through it. A Rogowski coil current sensor consists of two main components: a Rogowski coil sensor head and a subsequent signal integration and processing circuit. The sensor head is the signal sensing element of the measuring element, capturing the electromagnetic field in space and establishing a coupling relationship with the measured current. The Rogowski coil is characterized by its small size and low material cost, excellent linearity, and a wide measurement range. It is suitable for currents ranging from 0.1 In to tens of thousands of A or even larger. However, its disadvantage is that it is particularly susceptible to interference from electromagnetic fields, especially power-frequency electromagnetic fields. It is usually used for large current detection, such as AC current detection of hundreds of amperes or more. When used for small currents, it is extremely susceptible to interference from external power-frequency electromagnetic fields, so that the sampling current output by the Rogowski coil includes not only the measurement current flowing in the measured conductor but also the interference signal current generated by the surrounding electromagnetic field. When the measured current is small, the interference signal current may even cover the measured current, resulting in a large measurement error and an inability to properly reflect the actual current, resulting in certain limitations.

[0005] Therefore, in the field of electric power, especially under the strict requirements related to the safety of electricity use by the general public, how to optimize the transformer to improve its ability to resist external magnetic field interference is an issue that technical personnel in this field urgently need to study and solve. Summary of the Invention

[0006] The purpose of the present invention is to provide an anti-vertical magnetic field interference sensor that can resist or eliminate external vertical magnetic field interference.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0008] A sensor for resisting vertical magnetic field interference includes a Rogowski coil and a vertical magnetic field cancellation coil located on one side of the Rogowski coil and connected to the Rogowski coil. The Rogowski coil includes a plurality of hollow coils connected end to end. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil are consistent. The hollow coils are an even number of not less than four and are symmetrically distributed around a circle on the same horizontal plane. Output terminals are provided on the Rogowski coil and the vertical magnetic field cancellation coil.

[0009] As a further improvement of the present invention, the reclaimed area of ​​the vertical magnetic field offset coil is equal to the reclaimed area enclosed by the Rogowski coil.

[0010] As a further improvement of the present invention, the Rogowski coil includes 8 hollow coils with a circular cross-section, and the hollow coils are provided with several single coil layers arranged from the inside to the outside. From the cross-section, the inner diameter of each hollow coil is 2 cm and the outer diameter is 4.2 cm, and the single coil layer is set to 11 layers. The inner diameter of the vertical magnetic field compensation coil is set to 12.6 cm and the outer diameter is 13.4 cm, and 5 turns are arranged from the inside to the outside.

[0011] As a further improvement of the present invention, the vertical magnetic field cancellation coil is located on one side of the Rogowski coil and is parallel to the Rogowski coil; the Rogowski coils are symmetrically distributed with a circle as the center on the same horizontal plane and are provided with a primary current passing center for a primary current line to pass through, and the center of the vertical magnetic field cancellation coil coincides with the primary current passing center.

[0012] As a further improvement of the present invention, the vertical magnetic field cancellation coil is a ring coil that is continuously wound from the inside to the outside.

[0013] As a further improvement of the present invention, the vertical magnetic field compensation coil is a ring circuit formed by continuously winding from the inside to the outside on the ring circuit board.

[0014] As a further improvement of the present invention, the Rogowski coil is formed by continuously winding an enameled wire.

[0015] As a further improvement of the present invention, the anti-vertical magnetic field interference sensor also includes a shell for accommodating the Rogowski coil and the vertical magnetic field cancellation coil, the shell includes an annular bottom wall, an inner wall extending laterally from the inner circle of the bottom wall, and an outer wall extending laterally from the outer circle of the bottom wall, the bottom wall, inner wall, and outer wall form a semi-open annular accommodating cavity, the Rogowski coil is accommodated in the accommodating cavity, the inner wall is penetrated around the center of the Rogowski coil, forming a primary current through hole for allowing a primary current line to pass through the center of the Rogowski coil and the vertical magnetic field cancellation coil, a partition portion is provided in the accommodating cavity, forming a slot box for fixing each hollow coil, and each slot box is symmetrical with respect to a circle as the center.

[0016] As a further improvement of the present invention, the shell is made of PBT plus glass fiber or PPS plus glass fiber, and the coreless coil assembly is encapsulated with epoxy resin in the receiving cavity.

[0017] In order to achieve the above technical objectives, the present invention can also adopt the following technical means:

[0018] An electric power meter comprises an electric power meter housing and the aforementioned anti-vertical magnetic field interference sensor located in the electric power meter housing.

[0019] Compared to the prior art, the present invention's anti-vertical magnetic field interference sensor includes a Rogowski coil and a vertical magnetic field cancellation coil located on one side of the Rogowski coil and connected to the Rogowski coil. The Rogowski coil includes several hollow coils connected end to end. Each hollow coil has a consistent wire diameter, number of turns, number of layers, inner diameter, and outer diameter, and is symmetrically distributed around a circle on the same horizontal plane. The Rogowski coil and the vertical magnetic field cancellation coil enable the anti-vertical magnetic field interference sensor to offset external magnetic field interference from all directions as a whole. This solves the technical problem that conventional Rogowski coils are extremely susceptible to interference from external power frequency electromagnetic fields when used for low current detection, resulting in large measurement errors and an inability to properly reflect the actual current. This overcomes the limitations of current Rogowski coil applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the Rogowski coil and the vertical magnetic field cancellation coil of the first embodiment of the anti-vertical magnetic field interference sensor of the present invention;

[0021] Figure 2 This is a structural diagram of the Rogowski coil and the vertical magnetic field cancellation coil of the first embodiment of the anti-vertical magnetic field interference sensor of the present invention before installation and positioning;

[0022] Figure 3 This is another structural schematic diagram of the Rogowski coil and the vertical magnetic field cancellation coil of the first embodiment of the anti-vertical magnetic field interference sensor of the present invention before installation and positioning;

[0023] Figure 4 This is a schematic structural diagram of the first embodiment of the anti-vertical magnetic field interference sensor of the present invention when the Rogowski coil and the vertical magnetic field cancellation coil are installed and positioned;

[0024] Figure 5 It is a structural schematic diagram of the housing of the sensor for resisting vertical magnetic field interference of the present invention;

[0025] Figure 6 Schematic diagram of the internal structure of the first embodiment of the sensor for resisting vertical magnetic field interference of the present invention;

[0026] Figure 7Schematic diagram of the decomposition of the structure of the Rogowski coil and the vertical magnetic field cancellation coil of the second embodiment of the anti-vertical magnetic field interference sensor of the present invention;

[0027] Figure 8 Schematic diagram of the structure of the Rogowski coil and the vertical magnetic field cancellation coil of the second embodiment of the anti-vertical magnetic field interference sensor of the present invention;

[0028] Figure 9 This is a schematic diagram of the structure decomposition of the second embodiment of the sensor for resisting vertical magnetic field interference of the present invention;

[0029] Figure 10 Schematic diagram of the internal structure of the second embodiment of the vertical magnetic field interference sensor of the present invention;

[0030] Figure 11 FIG. 2 is a schematic diagram of the internal structure of the second embodiment of the sensor for resisting vertical magnetic field interference according to the present invention from another angle.

[0031] Reference numerals:

[0032] Anti-vertical magnetic field interference sensor 100, 200 enameled wire 1

[0033] Rogowski coil 2 Air-core coil 20

[0034] The primary current passes through the center 201 single coil layer 2210

[0035] Vertical magnetic field cancellation coils 3, 4 Ring coil 30

[0036] Ring circuit 40 Ring circuit board 41

[0037] Output terminal 5, 5' housing 6

[0038] Bottom wall 61 Partition portion 611

[0039] Trough box 610 outer wall 62

[0040] Inner wall 63 Primary current passes through hole 630

[0041] Accommodation cavity 64 DETAILED DESCRIPTION

[0042] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0043] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0044] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0045] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0046] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0047] Please refer to Figures 1 to 7The figure shows a schematic diagram of the structure of the first embodiment of the anti-vertical magnetic field interference sensor 100 of the present invention. An anti-vertical magnetic field interference sensor 100 includes a Rogowski coil 2 and a vertical magnetic field cancellation coil 3 located on one side of the Rogowski coil 2 and connected to the Rogowski coil 2. The Rogowski coil 2 includes a plurality of hollow coils 20 connected end to end. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil 20 are consistent. It is worth noting that in the present invention, the specific winding method of the hollow coil 20 is not limited. As long as the wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil 20 can be kept consistent, it is within the scope of protection of the present invention. The hollow coils 20 are an even number of not less than 4, and are symmetrically distributed on the same horizontal plane with a circle as the center. The Rogowski coil 2 and the vertical magnetic field cancellation coil 3 are provided with an output terminal 5.With this configuration, the vertical magnetic field interference resistant sensor 100 has no magnetic saturation, making it extremely suitable for measuring very large currents, currents containing DC components (such as short-circuit fault currents and currents in power electronic equipment), and severely distorted currents. It also has a wide frequency response, without the limitations of eddy current loss, hysteresis loss, and distributed capacitance caused by the iron core, and a very wide bandwidth (from a few Hz to several MHz, or even higher), enabling it to accurately measure high-frequency currents, fast transient currents (such as lightning strikes, switching operation surges, and fast turn-off currents of power electronic switches), and currents containing rich harmonics. It also has good linearity, with the output signal (induced voltage) strictly proportional to the rate of change of the measured current (di / d t), when the coil design parameters (such as turn density, cross-sectional area) remain unchanged and there is no saturation, its response is linear, so that it maintains a good linear relationship between the input (current change rate) and the output (voltage) in the entire measurement range, and the measurement accuracy is high; low load effect, relatively low output impedance, very small load effect on the measured circuit, almost no impact on the measured current loop, making it easy to connect to the measurement system; flexible, lightweight, easy to install, easy to install in places with limited space, the coil itself has good electrical isolation from the high-voltage conductor being measured, improving operational safety; wide measurement range, by adjusting the number of coil turns and other device parameters, the same coil design can cover a very wide range of current measurement range (from a few amperes to millions of amperes), without the need for different transformation ratios like traditional CT; there is no residual magnetism, and no residual magnetism will be left after measurement, which will not affect the accuracy of the next measurement. It is particularly suitable for measuring non-periodic transient large currents; and the center of the Rogowski coil 2, which is symmetrically distributed with a circle as the center, can be used for the primary current line to pass through, and the output end 5 can perform electromagnetic induction detection on the current flowing through the primary current line and output a corresponding signal. The Rogowski coil 2 of the present invention can better maintain the consistency of the structure and distribution of each hollow coil 20, and the even number of hollow coils 20 symmetrically distributed on the axis can evenly offset the induced electromotive force generated by each other when disturbed by the external magnetic field, thereby achieving The invention has a better ability to resist external magnetic field interference, thereby improving the detection accuracy and anti-interference performance of the electric meter; and when subjected to magnetic field interference perpendicular to the plane in which the Rogowski coil 2 is distributed, the vertical magnetic field cancellation coil 3 can better offset the induced electromotive force generated by the Rogowski coil 2 itself. With this arrangement, the Rogowski coil 2 and the vertical magnetic field cancellation coil 3 can enable the anti-vertical magnetic field interference sensor 100 to offset external magnetic field interference from all directions as a whole, solving the technical problem that the current ordinary Rogowski coil (not shown) is easily affected by external power frequency electromagnetic field interference when used for small current detection, thereby causing large measurement errors and failing to properly reflect the actual current, thus breaking through the limitations of the current application of Rogowski coils.

[0048] Preferably, the area of ​​the vertical magnetic field cancellation coil 3 is equal to the area of ​​the vertical magnetic field cancellation coil 2. In this way, the Rogowski coil 2 and the vertical magnetic field cancellation coil 3 can enable the anti-vertical magnetic field interference sensor 100 to completely cancel the external magnetic field interference from all directions as a whole. For example, in this embodiment, the hollow coil 20 is provided with a plurality of single coil layers 2210 arranged neatly from the inside to the outside, and the number of turns, number of layers, inner diameter, and outer diameter of each hollow coil 20 are consistent, such as Figure 1 As shown, there are 7 layers of single coil layers 2210 from the inside out. The reclaimed area is now taken as an example: 8 hollow coils 20 with a circular cross section are set. From the cross section, each hollow coil 20 has an inner diameter of 2 cm and an outer diameter of 4.2 cm. There are 11 layers of single coil layers 2210 from the inside out. Thus, the reclaimed area is approximately 2655.4352 cm 2 On this basis, the inner diameter of the vertical magnetic field cancellation coil 3 is set to 12.6 cm, the outer diameter is 13.4 cm, and 5 turns are set from the inside to the outside. Then the reclamation area of ​​the vertical magnetic field cancellation coil 3 is approximately 2653.3 cm 2 , the reclaimed areas of the two coils are substantially the same. This allows the reclaimed area of ​​the vertical magnetic field cancellation coil 3 to be equal to the reclaimed area of ​​the Rogowski coil 2. When subjected to vertical power-frequency magnetic field interference, the induced electromotive forces generated by the Rogowski coil 2 and the vertical magnetic field cancellation coil 3 can cancel each other, thereby better protecting against power-frequency magnetic field interference. Of course, other embodiments, as long as the reclaimed areas of the two coils are substantially the same, are within the scope of protection of the present invention.

[0049] The vertical magnetic field cancellation coil 3 is located on one side of and parallel to the Rogowski coil 2. The Rogowski coils 2, symmetrically arranged about a circle on the same horizontal plane, are provided with a primary current passageway 201 for the primary current line to pass through. The center of the vertical magnetic field cancellation coil 3 coincides with the primary current passageway 201. This arrangement effectively cancels the induced electromotive force generated by the Rogowski coil 2 and the vertical magnetic field cancellation coil 3 when subjected to a vertical power-frequency magnetic field, thereby providing enhanced protection against power-frequency magnetic field interference.

[0050] Ginseng Figures 1 to 6 As shown, in the first embodiment of the present invention, the vertical magnetic field cancellation coil 3 is a ring coil 30 that is continuously wound from the inside to the outside. In this way, the vertical magnetic field cancellation coil 3 can be continuously wound from the end of the Rogowski coil 2, which is easy to manufacture and install.

[0051] Ginseng Figures 7 to 11As shown, in the second embodiment of the present invention, the vertical magnetic field cancellation coil 4 is a ring circuit 40 formed by continuously winding from the inside out on a ring circuit board 41. Specifically, a ring circuit 40 similar to the ring coil 30 described in the first embodiment is provided on the ring circuit board 41, and the output end 5' is provided on the Rogowski coil 2 and the ring circuit board 41. This arrangement further solidifies the ring circuit 40, facilitating precise installation and positioning of the vertical magnetic field cancellation coil 4 and the Rogowski coil 2.

[0052] Preferably, the Rogowski coil 2 is formed by continuously winding a single enameled wire 1. This configuration facilitates the manufacture of the Rogowski coil 2 and the consistency of the structural parameters of each hollow coil 20, and facilitates the cancellation of the induced electromotive force generated by the hollow coils 20 due to external magnetic field interference.

[0053] Ginseng Figure 5 The anti-vertical magnetic field interference sensor 100, 200 also includes a shell 6 for accommodating the Rogowski coil 2 and the vertical magnetic field cancellation coils 3, 4. The shell 6 includes an annular bottom wall 61, an inner wall 63 extending laterally from the inner circle of the bottom wall 61, and an outer wall 62 extending laterally from the outer circle of the bottom wall 61. The bottom wall 61, inner wall 63, and outer wall 62 form a semi-open annular accommodating cavity 64. The Rogowski coil 2 is accommodated in the accommodating cavity 64. The inner wall 63 is arranged around the center of the Rogowski coil 2 to form a primary current through hole 630 for allowing a primary current line to pass through the center of the Rogowski coil 2 and the vertical magnetic field cancellation coils 3, 4. A partition portion 611 is provided in the accommodating cavity 64 to form a slot box 610 for fixing each air-core coil 20. Each slot box 610 is symmetrical with respect to a circle. With such a configuration, the accommodating cavity 64 of the shell 6 can more stably accommodate the Rogowski coil 2 and the vertical magnetic field cancellation coils 3 and 4, and the primary current line can just pass through the center of the Rogowski coil 2 and the vertical magnetic field cancellation coils 3 and 4, thereby accurately sensing the flow information of the primary current line, and making the various uniformly regulated hollow coils 20 without the Rogowski coil 2 uniformly surround the primary current line to offset the induced electromotive force generated by external magnetic field interference, and the vertical magnetic field cancellation coils 3 and 4 are uniformly surrounded by the primary current line, which can offset the induced electromotive force generated by external vertical magnetic field interference. The slot box 610 is roughly rectangular in shape, which can just hold and accommodate a single hollow coil 20, so that each hollow coil 20 is evenly distributed according to the above requirements, and their positions are fixed before and after the Rogowski coil 2 and the vertical magnetic field cancellation coils 3 and 4 are encapsulated, thereby effectively avoiding the influence of external electromagnetic interference on measurement accuracy from all aspects.

[0054] The housing 6 is made of PBT and glass fiber or PPS and glass fiber, and the coreless coil assembly is encapsulated with epoxy resin in the receiving cavity 64. This improves the strength and corrosion resistance of the housing 6 and increases the service life of the entire anti-vertical magnetic field interference sensor 100, 200.

[0055] The present invention also protects an electric power meter, comprising an electric power meter housing and an anti-perpendicular magnetic field interference sensor 100, 200 located within the housing. The core component of the electric power meter lies in the resistance of the anti-perpendicular magnetic field interference sensor 100, 200 to external magnetic field interference. This resistance to external magnetic field interference enables the electric power meter to have excellent power data detection accuracy, giving the electric power meter a core competitive advantage in the market.

[0056] It is worth noting that, in the present invention, the order of the above steps is not limited and can be adjusted according to actual conditions, all within the scope of protection of the present invention.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0058] The series of directional words such as front, back, left, right, up, and down used in the technical features of the above-described embodiments are only used to facilitate the description and understanding of the various technical features and do not constitute a restriction on specific directions in the actual use of the technical solutions.

[0059] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A sensor resistant to vertical magnetic field interference, characterized in that: The device comprises a Rogowski coil and a vertical magnetic field cancellation coil located on one side of the Rogowski coil and connected to the Rogowski coil. The Rogowski coil comprises a plurality of hollow coils connected end to end. The wire diameter, number of turns, number of layers, inner diameter, and outer diameter of each hollow coil are consistent. The hollow coils are an even number of not less than four and are symmetrically distributed around a circle on the same horizontal plane. Output terminals are provided on the Rogowski coil and the vertical magnetic field cancellation coil.

2. The vertical magnetic field interference resistant sensor according to claim 1, characterized in that: The reclaimed area of ​​the vertical magnetic field offset coil is equal to the reclaimed area enclosed by the Rogowski coil.

3. The vertical magnetic field interference resistant sensor according to claim 1, characterized in that: The Rogowski coil includes 8 hollow coils with a circular cross-section. The hollow coils are provided with several single coil layers arranged from the inside to the outside. From the cross-section, the inner diameter of each hollow coil is 2 cm and the outer diameter is 4.2 cm. There are 11 single coil layers. The inner diameter of the vertical magnetic field compensation coil is set to 12.6 cm and the outer diameter is 13.4 cm. There are 5 turns from the inside to the outside.

4. The vertical magnetic field interference resistant sensor according to claim 1, characterized in that: The vertical magnetic field cancellation coil is located on one side of the Rogowski coil and is parallel to the Rogowski coil; the Rogowski coils are symmetrically distributed with a circle as the center on the same horizontal plane and are provided with a primary current passing center for a primary current line to pass through, and the center of the vertical magnetic field cancellation coil coincides with the primary current passing center.

5. The vertical magnetic field interference resistant sensor according to claim 1, characterized in that: The vertical magnetic field cancellation coil is a ring coil that is continuously wound from the inside to the outside.

6. The sensor for resisting vertical magnetic field interference according to claim 1, characterized in that: The vertical magnetic field cancellation coil is a ring circuit formed by continuously winding from the inside to the outside on the ring circuit board.

7. The sensor for resisting vertical magnetic field interference according to claim 1, characterized in that: The Rogowski coil is formed by continuously winding an enameled wire.

8. The sensor for resisting vertical magnetic field interference according to claim 1, characterized in that: The anti-vertical magnetic field interference sensor also includes a shell for accommodating the Rogowski coil and the vertical magnetic field cancellation coil. The shell includes an annular bottom wall, an inner wall extending laterally from the inner circle of the bottom wall, and an outer wall extending laterally from the outer circle of the bottom wall. The bottom wall, inner wall, and outer wall form a semi-open annular accommodating cavity. The Rogowski coil is accommodated in the accommodating cavity. The inner wall is penetrated around the center of the Rogowski coil to form a primary current passage hole for allowing a primary current line to pass through the center of the Rogowski coil and the vertical magnetic field cancellation coil. A partition portion is provided in the accommodating cavity to form a slot box for fixing each hollow coil. Each slot box is symmetrical with respect to a circle.

9. The sensor for resisting vertical magnetic field interference according to claim 8, characterized in that: The shell is made of PBT plus glass fiber or PPS plus glass fiber, and the coreless coil assembly is encapsulated in the receiving cavity with epoxy resin.

10. An electric power meter, characterized in that: The utility model comprises an electric power meter housing and an anti-vertical magnetic field interference sensor according to any one of claims 1 to 9 located in the electric power meter housing.

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