阅读说明：本技术 一种电流互感器 (Current transformer ) 是由 房鑫 陈奕嘉 邢江波 金光耀 岳光华 贺小维 赵新科 张润杰 陈德金 张海宾 于 2020-12-09 设计创作，主要内容包括：本发明涉及一种电流互感器,属于电流检测技术领域。电流互感器包括一次侧和二次侧,所述二次侧包括保护级线圈、测量级线圈、计量级线圈和TPY级线圈,所述计量级线圈包括：铁芯、以及由内到外依次环绕铁芯缠绕的内绝缘层、电磁线层、外绝缘层；还包括：屏蔽层,设置在外绝缘层外侧,用于屏蔽TPY级线圈气隙所产生的漏磁。本发明通过在计量级线圈的外侧设置屏蔽层,该屏蔽层可以产生一层闭合的电磁场,将TPY级线圈气隙所产生的漏磁屏蔽掉,避免了计量级线圈的测量误差,保证计量级线圈计量的准确性。(The invention relates to a current transformer, and belongs to the technical field of current detection. The current transformer comprises a primary side and a secondary side, the secondary side comprises a protection level coil, a measurement level coil, a metering level coil and a TPY level coil, and the metering level coil comprises: the electromagnetic wire comprises an iron core, and an inner insulating layer, an electromagnetic wire layer and an outer insulating layer which are sequentially wound around the iron core from inside to outside; further comprising: and the shielding layer is arranged on the outer side of the outer insulating layer and used for shielding magnetic leakage generated by the air gap of the TPY-level coil. According to the invention, the shielding layer is arranged on the outer side of the metering level coil, and can generate a layer of closed electromagnetic field to shield leakage magnetic generated by the air gap of the TPY level coil, so that the measurement error of the metering level coil is avoided, and the metering accuracy of the metering level coil is ensured.)

1. A current transformer comprises a primary side and a secondary side, wherein the secondary side comprises a protection level coil, a measurement level coil, a metering level coil and a TPY level coil, and is characterized in that the metering level coil comprises:

the electromagnetic wire comprises an iron core, and an inner insulating layer, an electromagnetic wire layer and an outer insulating layer which are sequentially wound around the iron core from inside to outside;

further comprising:

and the shielding layer is arranged on the outer side of the outer insulating layer and used for shielding magnetic leakage generated by the air gap of the TPY-level coil.

2. The current transformer of claim 1, wherein the shield layer comprises a winding of wire wound outside the outer insulating layer and an insulating medium wound outside the winding.

3. The current transformer according to claim 2, wherein the number of winding turns of the winding is set according to the size of the metering coil.

4. The current transformer according to claim 2, wherein the winding comprises n equally divided sub-windings, the n sub-windings cover the whole outer insulation layer, the winding direction of each sub-winding is consistent, and the winding direction is set as the head end and the tail end of the sub-winding, the head end of each sub-winding is connected, and the tail end of each sub-winding is connected.

5. The current transformer of claim 1, wherein the core is a toroidal core.

6. The current transformer of claim 2, wherein the insulating medium is mylar.

7. The current transformer according to claim 2, characterized in that the wire is a round enameled wire.

Technical Field

The invention relates to a current transformer, and belongs to the technical field of current detection.

Background

As shown in fig. 1, a secondary side of an existing current transformer includes a protection-stage coil 1, a measurement-stage coil 2, a measurement-stage coil 3, a TPY-stage coil 4 (i.e., a transient protection TPY coil), and a TPY-stage coil 5, which can implement functions of current measurement, meter display, and line protection. The structure of the metering level coil 3 is shown in fig. 2, and mainly comprises an annular iron core 31, electromagnetic wires (circular enameled wires) and an insulating material (polyester film), and the winding method of the metering level coil 3 is as follows: according to technical process requirements, firstly, an inner insulating layer 32 made of polyester film insulating material is wound on the outer surface of the annular iron core 31; then winding an electromagnetic wire layer 33 formed by a plurality of layers of electromagnetic wires according to parameter requirements, wherein polyester film insulation needs to be wound between the layers of the electromagnetic wire layer 33 to ensure interlayer insulation; and finally an outer insulating layer 34 of polyester film is wound on the outermost layer.

Generally, a current transformer is adopted in a voltage class line of 500kV or above for current detection, the primary current of the line is too large, generally above 4000A, when a plurality of windings are combined together, the phenomenon of air gap leakage of a TPY (tire pressure gauge) class coil is easy to occur under the condition that a large current above 4000A flows through a metering class coil 3, so that errors occur, and the phenomenon of unqualified metering occurs.

Therefore, a novel current transformer needs to be provided to meet the structural requirement of the electrical performance of the product, eliminate the influence of the air gap leakage flux of the TPY-level coil on the error data of the metering-level coil 3 and ensure the product quality.

Disclosure of Invention

An object of the application is to provide a current transformer for solve the problem that current transformer accuracy of measurement is low.

In order to achieve the above object, the present application provides a technical solution of a current transformer, the current transformer includes a primary side and a secondary side, the secondary side includes a protection stage coil, a measurement stage coil and a TPY stage coil, the measurement stage coil includes:

the electromagnetic wire comprises an iron core, and an inner insulating layer, an electromagnetic wire layer and an outer insulating layer which are sequentially wound around the iron core from inside to outside;

further comprising:

and the shielding layer is arranged on the outer side of the outer insulating layer and used for shielding magnetic leakage generated by the air gap of the TPY-level coil.

The technical scheme of the current transformer has the beneficial effects that: according to the invention, the shielding layer is arranged on the outer side of the metering level coil, and can generate a layer of closed electromagnetic field to shield leakage magnetic generated by the air gap of the TPY level coil, so that the measurement error of the metering level coil is avoided, and the metering accuracy of the metering level coil is ensured.

Further, the shielding layer comprises a winding formed by a conducting wire and an insulating medium, the winding is wound on the outer side of the outer insulating layer, and the insulating medium is wound on the outer side of the winding.

Furthermore, in order to ensure the shielding effect and improve the metering accuracy, the winding turns of the winding are set according to the size of the metering coil.

Furthermore, in order to improve the shielding effect, the winding comprises n sub-windings which are equally divided, the n sub-windings cover the whole outer insulating layer, the winding direction of each sub-winding is consistent, the head end and the tail end of each sub-winding are sequentially arranged according to the set winding direction, the head end of each sub-winding is connected, and the tail end of each sub-winding is connected.

Further, the iron core is an annular iron core.

Further, the insulating medium is a polyester film.

Further, the conducting wire is a round enameled wire.

Drawings

FIG. 1 is a diagram of a secondary side of a current transformer in the prior art;

FIG. 2 is a cross-sectional view of a secondary side metering coil of a current transformer in the prior art;

FIG. 3 is a cross-sectional view of a secondary side metering coil of the current transformer of the present invention;

FIG. 4 is a distribution diagram of the sub-windings in the shield of the metrological level coil of the present invention;

in the figure: the transformer comprises a protection level coil 1, a measurement level coil 2, a metering level coil 3, TPY level coils 4 and 5, an annular iron core 31, an inner insulating layer 32, an electromagnetic wire layer 33, an outer insulating layer 34 and a shielding layer 35.

Detailed Description

The embodiment of the current transformer comprises:

the current transformer has the main concept that based on the problem that the measuring coil has large current, magnetic leakage is generated at the air gap of the TPY coil, and the measuring accuracy is further influenced, the shielding layer is arranged on the outer side of the measuring coil to shield the influence of the magnetic leakage generated at the air gap of the TPY coil on the magnetic field of the TPY coil, so that the measuring error is avoided, and the accuracy of the measuring result is ensured.

Specifically, as shown in fig. 1, the current transformer provided by the present invention includes a primary side and a secondary side, the secondary side includes a protection-stage coil 1, a measurement-stage coil 2, a measurement-stage coil 3, a TPY-stage coil 4, and a TPY-stage coil 5, and the arrangement of the coils is the same as that in the prior art, which is not described herein again.

The metering level coil 3 includes an annular iron core 31, and an inner insulating layer 32, an electromagnetic wire layer 33, an outer insulating layer 34 and a shielding layer 35 which are sequentially wound around the annular iron core 31 from inside to outside, as shown in fig. 3.

The shielding layer 35 sets up the outside of outer insulating layer 34, and shielding layer 35 includes the winding and the polyester film (polyester film is a kind of material of insulating medium) that are formed by circular enameled wire (circular enameled wire is a model of wire), and the winding is twined in the outside of outer insulating layer 34, and the polyester film winding is in the winding outside, and the design and the winding mode of winding are as follows:

firstly, designing the winding turns N of a winding according to the inner and outer diameter sizes of a magnitude coil 3, and dividing the winding turns of the winding into N equal parts to form N sub-windings, wherein the winding turns of each sub-winding are N/N;

secondly, as shown in fig. 4, winding n sub-windings outside the outer insulation layer 34 to cover the whole outer insulation layer 34, wherein the winding direction of each sub-winding is consistent, the winding direction is the head end and the tail end of each sub-winding in sequence, the head end of each sub-winding is connected, and the tail end of each sub-winding is connected to form a closed magnetic field, so as to achieve the purpose of shielding;

and finally, winding a polyester film on the outer side of the winding after the winding and connection of the sub-windings are finished.

For example: the winding turns of the winding are designed to be 1000 turns according to requirements, the winding turns of the winding are equally divided into 4 turns, the turns of each sub-winding are 1000 turns/4-250 turns, after the winding of each sub-winding is finished according to the distribution shown in figure 4, the head ends of the 4 sub-windings are connected, the tail ends of the 4 sub-windings are connected, and finally the polyester film is wound.

In the above embodiment, in order to ensure that the winding can cover the entire outer insulating layer 34 and improve the shielding effect, the number of winding turns of the winding is designed according to the inner and outer diameter dimensions of the metering-level coil 3, as another embodiment, the number of winding turns of the winding may also be directly set, which is not limited by the present invention.

In the above embodiment, the shielding layer 35 is composed of a winding and an insulating medium wound on the outer insulating layer 34, as another embodiment, the specific structure of the shielding layer 35 is not limited in the present invention, as long as the corresponding shielding function is achieved.

In the above embodiment, the winding is equally divided into 4 equal parts, and then there are 4 sub-windings, as another embodiment, the winding may also be divided into 6 equal parts or 8 equal parts, and the number of the equal parts is not limited in the present invention, but the head ends of the sub-windings are connected, and the tail ends of the sub-windings are connected, so as to achieve the shielding effect.

The invention is not limited with regard to the shape of the iron core, the type of the lead and the material of the insulating medium, and can realize corresponding functions.

The invention ensures that the shielding layer 35 of the metering level coil 3 can generate a closed electromagnetic field to form a shielding device when the primary side of the metering level coil 3 is introduced with a large current of 4000A or more, thereby preventing the magnetic leakage generated at the air gap between the TPY level coil 4 and the TPY level coil 5, not influencing the magnetic field of the current transformer, reducing the precision error and ensuring the qualified metering data.