CN215933368U

CN215933368U - Current transformer

Info

Publication number: CN215933368U
Application number: CN202122418314.1U
Authority: CN
Inventors: 李荣攀
Original assignee: Individual
Current assignee: Zhejiang Xicheng Electric Power Equipment Co.,Ltd.
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2022-03-01
Anticipated expiration: 2031-10-08

Abstract

The utility model provides a current transformer, which relates to the technical field of transformers and comprises an insulating shell, and an A-phase current transformer, a B-phase current transformer, a C-phase current transformer and a zero sequence current transformer which are positioned in the insulating shell, wherein the zero sequence current transformer is sleeved on the A-phase current transformer, the B-phase current transformer and the C-phase current transformer, and an electromagnetic shielding cover is covered on the outer side of the insulating shell; the insulation shell is provided with evenly distributed A-phase threading holes, B-phase threading holes and C-phase threading holes, the A-phase current transformer is arranged on the outer side of the A-phase threading holes, the B-phase current transformer is arranged on the outer side of the B-phase threading holes, and the C-phase current transformer is arranged on the outer side of the C-phase threading holes; the method and the device effectively reduce the residual current value, improve the safety performance and the measurement precision of the current transformer and realize the high-precision monitoring of the zero-sequence current.

Description

Current transformer

Technical Field

The utility model relates to the technical field of transformers, in particular to a current transformer.

Background

The current transformer has the function of converting primary current with a larger value into secondary current with a smaller value through a certain transformation ratio for protection, measurement and other purposes. The principle of the current transformer is based on the electromagnetic induction principle, the current transformer is composed of a closed iron core and a winding, the number of turns of a primary side winding of the current transformer is small, and the primary side winding is connected in a circuit of current to be measured in series, so that all current of the circuit always flows through the current transformer, the number of turns of a secondary side winding is large, the secondary side winding is connected in a measuring instrument and a protection loop in series, when the current transformer works, a secondary side loop of the current transformer is always closed, therefore, the impedance of the series coil of the measuring instrument and the protection loop is small, and the working state of the current transformer is close to short circuit. The current transformer converts a large current on the primary side into a small current on the secondary side for use, and the secondary side cannot be opened. As can be seen from the above, in the existing circuit breaker circuit design, the current transformer plays an important role in the whole circuit breaker operation. The current transformer can be mainly used for monitoring corresponding current, and when the normal value of current operation deviates, the current transformer can perform corresponding treatment measures, such as disconnecting a circuit breaker or transmitting fault current to a server.

However, the zero sequence transformer widely used in the market is composed of a transformer housing, a transformer magnetic core accommodated in the housing and a winding on the magnetic core, and because the grounding current is small, the zero sequence transformer with the structure has a large measurement error, is difficult to measure with high precision, even causes the zero sequence transformer to be incapable of working normally, leaves hidden danger for the safety of a power grid, occupies a large space, and is easily interfered by external electromagnetism or higher harmonics, so that improvement is needed on the basis.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a current transformer which can reduce the space occupation.

The embodiment of the utility model is realized by the following steps:

the embodiment of the application provides a current transformer, which comprises an insulating shell, and an A-phase current transformer, a B-phase current transformer, a C-phase current transformer and a zero-sequence current transformer which are positioned in the insulating shell, wherein the zero-sequence current transformer is sleeved on the A-phase current transformer, the B-phase current transformer and the C-phase current transformer, and an electromagnetic shielding cover is covered on the outer side of the insulating shell; the insulation shell is provided with an A-phase threading hole, a B-phase threading hole and a C-phase threading hole which are uniformly distributed, the A-phase current transformer is arranged on the outer side of the A-phase threading hole, the B-phase current transformer is arranged on the outer side of the B-phase threading hole, and the C-phase current transformer is arranged on the outer side of the C-phase threading hole.

In some embodiments of the present invention, the a-phase current transformer includes an a-phase iron core and a-phase current coil winding wound around the a-phase iron core, the B-phase current transformer includes a B-phase iron core and a B-phase current coil winding wound around the B-phase iron core, and the C-phase current transformer includes a C-phase iron core and a C-phase current coil winding wound around the C-phase iron core.

Therefore, the A, B, C phase iron cores are respectively wound with the A, B, C phase current coil windings, the zero sequence iron core of the zero sequence current transformer and the zero sequence current coil windings wound on the zero sequence iron core are conveniently integrated with the zero sequence iron core, the occupied volume of components can be reduced, the occupied space for installation can be saved, and the safety performance and the measurement precision of the current transformer are improved.

In some embodiments of the present invention, an electromagnetic shielding layer is disposed outside each of the a-phase current coil winding, the B-phase current coil winding, and the C-phase current coil winding.

Therefore, the electromagnetic shielding layer is arranged on the outer side of the A, B, C phase current coil winding, the electromagnetic shielding layer can be matched with the electromagnetic shielding cover on the outer side of the insulating shell, the interference of external electromagnetism and higher harmonics to the current transformer is further prevented, and the operation safety and the measurement precision of the current transformer are improved.

In some embodiments of the present invention, the phase a iron core, the phase B iron core, and the phase C iron core are composite annular iron cores in which silicon steel sheets and alloy sheets are stacked.

Therefore, the composite annular iron core with the silicon steel sheets and the alloy sheets superposed can improve the magnetic conduction effect, thereby lightening the weight of equipment, saving the space and improving the operation efficiency.

In some embodiments of the present invention, the distances between the threading holes a and B, and between the threading holes B and C are 210 mm.

Therefore, the accurate phase distance of 210mm is set, the protection of an indoor high-voltage circuit breaker is matched, the power frequency withstand voltage of 42KV can be borne, and the stability of the safety protection performance of the high-voltage circuit breaker is improved.

In some embodiments of the present invention, a fixing seat is disposed below the insulating housing.

Therefore, the current transformer can be conveniently installed and maintained through the fixing seat.

In some embodiments of the present invention, a cover plate is disposed above the insulating housing.

Therefore, the cover plate can be matched with the fixed seat so as to be used for opening or closing the shell cover of the insulating shell.

In some embodiments of the present invention, a plurality of mounting holes are formed at the periphery of the fixing base and the cover plate.

From this, accessible mounting hole is with insulating casing fixed mounting in the inside of fixing base and apron.

In some embodiments of the present invention, the fixing base and the cover plate are both made of aluminum-iron alloy.

Therefore, the aluminum-iron alloy can effectively shield external electric measurement and interference of higher harmonics, avoid the superposition of extra current on the current transformer, and improve the operation safety and the measurement precision of the current transformer

In some embodiments of the present invention, the insulating housing is formed by pouring a silicone rubber potting compound.

Therefore, the silica gel material can fix, insulate and improve the safety performance of the current transformer for A, B, C three-phase iron core, A, B, C three-phase current coil winding wound on A, B, C three-phase iron core and zero sequence current transformer, and the silica gel material can play the roles of moisture prevention, dust prevention, corrosion prevention and shock prevention, improve the use performance and stable parameters, and is convenient to fill and use.

Compared with the prior art, the embodiment of the utility model has at least the following advantages or beneficial effects:

The utility model provides a current transformer, close A, B, C three-phase current transformer and zero sequence current transformer into an organic whole closed structure through insulating casing, every looks all sets up independent iron core and current coil winding, the form of threading and totally closed wire winding form carry out the internal shield through three-phase cable phase splitting, the electromagnetic shield cover that the cooperation insulating casing outside cover was established, the effectual remaining current value that has reduced has improved current transformer's security performance and measurement accuracy, zero sequence current's high accuracy monitoring has been realized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic diagram of an internal structure of a current transformer according to embodiment 1 of the present invention;

fig. 2 is a schematic view of a fixing base structure of a current transformer according to embodiment 2 of the present invention;

fig. 3 is a schematic diagram of a structure of a cover plate of a current transformer according to embodiment 2 of the present invention.

Icon: 1. an insulating housing; 2. an A-phase current transformer; 21. a phase threading hole; 22. an A-phase iron core; 23. a phase A current coil winding; 3. a B-phase current transformer; 31. b phase threading holes; 32. a B-phase iron core; 33. a B-phase current coil winding; 4. a C-phase current transformer; 41. c phase threading holes; 42. a C-phase iron core; 43. a C-phase current coil winding; 5. a zero sequence current transformer; 6. an electromagnetic shield; 7. an electromagnetic shielding layer; 8. a fixed seat; 9. a cover plate; 10. and (7) installing holes.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate an orientation or a positional relationship based on the orientation or the positional relationship shown in the drawings, or an orientation or a positional relationship which is usually placed when the products of the present invention are used, the description is only for convenience and simplicity, and the indication or the suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, the present invention should not be construed as being limited.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not require that the components be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, "a plurality" represents at least 2.

In the description of the embodiments of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example 1

Referring to fig. 1, fig. 1 is a schematic diagram illustrating an internal structure of a current transformer according to embodiment 1 of the present invention.

The embodiment of the application provides a current transformer, which comprises an insulating shell 1, and an A-phase current transformer 2, a B-phase current transformer 3, a C-phase current transformer 4 and a zero sequence current transformer 5 which are positioned in the insulating shell 1, wherein the zero sequence current transformer 5 is sleeved on the A-phase current transformer 2, the B-phase current transformer 3 and the C-phase current transformer 4, and an electromagnetic shielding cover 6 is covered on the outer side of the insulating shell 1; a phase threading hole 21, a B phase threading hole 31 and a C phase threading hole 41 which are uniformly distributed are formed in the insulating shell 1, the A phase current transformer 2 is arranged on the outer side of the A phase threading hole 21, the B phase current transformer 3 is arranged on the outer side of the B phase threading hole 31, and the C phase current transformer 4 is arranged on the outer side of the C phase threading hole 41.

The phase-a current transformer 2, the phase-B current transformer 3 and the phase-C current transformer 4 may be arranged uniformly in a horizontal direction, or may be arranged in a rod-shaped through manner.

As a preferred embodiment, the a-phase current transformer 2 includes an a-phase iron core 22 and a-phase current coil winding 23 wound around the a-phase iron core 22, the B-phase current transformer 3 includes a B-phase iron core 32 and a B-phase current coil winding 33 wound around the B-phase iron core 32, and the C-phase current transformer 4 includes a C-phase iron core 42 and a C-phase current coil winding 43 wound around the C-phase iron core 42.

The head ends of the phase-a current coil winding 23, the phase-B current coil winding 33, and the phase-C current coil winding 43 are connected together and to one end of the secondary connection terminal, and the tail ends of the phase-a current coil winding 23, the phase-B current coil winding 33, and the phase-C current coil winding 43 are connected together and to the other end of the secondary connection terminal.

The phase-A current coil winding 23, the phase-B current coil winding 33 and the phase-C current coil winding 43 are respectively wound on the phase-A iron core 22, the phase-B iron core 32 and the phase-C iron core 42, so that the zero sequence iron core of the zero sequence current transformer 5 and the zero sequence current coil winding wound on the zero sequence iron core are conveniently integrated with each other, the occupied volume of components can be reduced, the occupied space for installation can be saved, and the safety performance and the measurement accuracy of the current transformer are improved.

In a preferred embodiment, the electromagnetic shield layer 7 is provided on the outer side of each of the phase-a current coil winding 23, the phase-B current coil winding 33, and the phase-C current coil winding 43.

The electromagnetic shielding layer 7 is arranged on the outer sides of the phase-A current coil winding 23, the phase-B current coil winding 33 and the phase-C current coil winding 43, and can be matched with the electromagnetic shielding cover 6 on the outer side of the insulating shell 1, so that the interference of external electromagnetism and higher harmonics on the current transformer is further prevented, and the operation safety and the measurement accuracy of the current transformer are improved.

As a preferred embodiment, the phase a iron core 22, the phase B iron core 32, and the phase C iron core 42 are composite annular iron cores formed by stacking silicon steel sheets and alloy sheets, and are used to improve the magnetic conduction effect of the iron cores, reduce the weight of the equipment, save space, and improve the operation efficiency.

As a better implementation mode, the distances between the A-phase threading hole 21 and the B-phase threading hole 31, and the distances between the B-phase threading hole 31 and the C-phase threading hole 41 are 210mm, so that the indoor high-voltage circuit breaker can be protected to bear the power frequency withstand voltage of 42KV, and the stability of the safety protection performance of the indoor high-voltage circuit breaker is improved.

As a preferred embodiment, the insulating housing 1 is formed by pouring a silicone rubber potting adhesive, so as to fix, insulate and improve the safety performance of the current transformer while fixing the a-phase iron core 22, the B-phase iron core 32, the C-phase iron core 42, the A, B, C three-phase current coil winding wound on the A, B, C three-phase iron core, and the zero-sequence current transformer 5, and also have the functions of moisture protection, dust protection, corrosion protection and shock protection, and improve the service performance and stable parameters of the insulating housing 1, thereby facilitating pouring and facilitating use.

It will be appreciated that the configuration shown in fig. 1 is merely illustrative and that a current transformer may include more or fewer components than shown in fig. 1 or may have a different configuration than shown in fig. 1. The components shown in fig. 1 may be implemented in hardware, software, or a combination thereof.

Example 2

Referring to fig. 2 and 3, fig. 2 is a schematic structural diagram of a fixing base 8 of a current transformer in embodiment 2 of the present invention, and fig. 3 is a schematic structural diagram of a cover plate 9 of the current transformer in embodiment 2 of the present invention.

As a better implementation mode, a fixing seat 8 is arranged below the insulating shell 1, so that the current transformer is convenient to install and maintain.

As a preferred embodiment, a cover plate 9 is disposed above the insulating housing 1, and can be matched with the fixing seat 8, so as to open or close the housing of the insulating housing 1.

In a preferred embodiment, a plurality of mounting holes 10 are formed around the fixing base 8 and the cover plate 9, and the insulating housing 1 is fixedly mounted inside the fixing base 8 and the cover plate 9.

As a better implementation mode, the fixed seat 8 and the cover plate 9 are both aluminum-iron alloy plates, so that the external electrical measurement and the interference of higher harmonics can be effectively shielded, the superposition of extra current of the current transformer is avoided, and the operation safety and the measurement precision of the current transformer are improved.

In summary, the embodiment of the present invention provides a current transformer, wherein an insulation casing 1 poured with silicone rubber potting adhesive is used to integrate A, B, C three-phase current transformer and a zero-sequence current transformer 5 into a whole to form a closed structure, each phase is provided with an independent iron core and a current coil winding, so that the current signal of each phase reaches the precision of the metering level, and then three-phase current synthesis is carried out, the three-phase cable is connected in a split-phase threading mode and is fixed by the fixing seat 8 and the cover plate 9, so that the space is saved, the current transformer can be directly fixed on the metering cabinet, the inner shielding is carried out through a fully-closed winding form, the electromagnetic shielding cover 6 which is covered on the outer side of the insulating shell 1 is matched, the residual current value is effectively reduced, the safety performance and the measuring accuracy of the current transformer are improved, and the high-precision monitoring of the zero-sequence current is realized.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A current transformer is characterized by comprising an insulating shell, and an A-phase current transformer, a B-phase current transformer, a C-phase current transformer and a zero sequence current transformer which are positioned in the insulating shell, wherein the zero sequence current transformer is sleeved on the A-phase current transformer, the B-phase current transformer and the C-phase current transformer, and an electromagnetic shielding cover is covered on the outer side of the insulating shell; the insulation shell is provided with an A-phase threading hole, a B-phase threading hole and a C-phase threading hole which are uniformly distributed, the A-phase current transformer is arranged on the outer side of the A-phase threading hole, the B-phase current transformer is arranged on the outer side of the B-phase threading hole, and the C-phase current transformer is arranged on the outer side of the C-phase threading hole.

2. The current transformer according to claim 1, wherein the a-phase current transformer includes an a-phase iron core and a-phase current coil winding wound around the a-phase iron core, the B-phase current transformer includes a B-phase iron core and a B-phase current coil winding wound around the B-phase iron core, and the C-phase current transformer includes a C-phase iron core and a C-phase current coil winding wound around the C-phase iron core.

3. The current transformer according to claim 2, wherein electromagnetic shielding layers are provided on outer sides of the a-phase current coil winding, the B-phase current coil winding and the C-phase current coil winding.

4. The current transformer according to claim 2, wherein the phase a iron core, the phase B iron core and the phase C iron core are composite annular iron cores formed by stacking silicon steel sheets and alloy sheets.

5. The current transformer according to claim 1, wherein distances between the a-phase threading hole and the B-phase threading hole, and between the B-phase threading hole and the C-phase threading hole are 210 mm.

6. The current transformer according to claim 1, wherein a fixing seat is arranged below the insulating shell.

7. The current transformer according to claim 6, wherein a cover plate is disposed above the insulating housing.

8. The current transformer of claim 7, wherein the periphery of the fixed base and the cover plate is provided with a plurality of mounting holes.

9. The current transformer of claim 8, wherein the fixing base and the cover plate are aluminum-iron alloy plates.

10. The current transformer of claim 1, wherein the insulating housing is formed by pouring silicone rubber potting compound.