KR20100131294A - Cast resin transformer and its making method - Google Patents

Abstract

PURPOSE: A cast resin transformer and a making method thereof are provided to minimize electric field stress to an insulating material by easing electric field concentration. CONSTITUTION: A mold transformer comprises an insulated conductor(10), a semi-conductive layer(20), and an insulating resin member(30). The insulated conductor is wound in vertical direction and is comprised of an electrical conductor part and an isolation coating layer. The semiconducting layer is formed on the insulated conductor in order to distribute electric field. The insulating resin member forms the outer shape of the mold transformer. The insulating resin member is casted in the insulated conductor and semiconducting layer.

Description

Mold transformer and manufacturing method of mold transformer {CAST RESIN TRANSFORMER AND ITS MAKING METHOD}

The present invention relates to a mold transformer (CAST RESIN TRANSFORMER, also known as MOLD TRANSFORMER), and more particularly to a mold transformer and a method of manufacturing the same that can reduce the electric field concentration and improve the dielectric strength.

Examples of transformers installed on the receiving side of substations or large-scale power consumers and rated voltages of several tens of kilovolts or more are dry transformers, inlet transformers and mold transformers.

Here, the inflow transformer is an unsuitable transformer for indoor use because it has a high rated voltage but uses oil which may cause environmental pollution as an insulation material and there is a risk of fire and explosion.

Dry-type transformers are air-insulated transformers with less risk of fire and explosion than inlet transformers.

Mold transformer is a structure that insulates the outside of transformer winding with solid insulator. It is an eco-friendly transformer that does not use oil that can cause environmental pollution as insulator, and uses insulator such as epoxy which has excellent flame retardancy as solid insulator. As the risk of fire and explosion is minimized, outdoor and indoor installation is possible, and the demand thereof is increasing.

However, in the mold transformer according to the prior art, the electric field formed by the current flowing through the internal winding is concentrated in some parts such as the upper end or the lower end of the winding, and the density of the other part is caused by the density of the other part due to the bubbles in the insulation around the part. If lower than that, there was a problem that can cause insulation breakdown and power failure in the site.

Therefore, the present invention is to solve the problems of the prior art, the first object of the present invention is to insulate by minimizing the electric field stress (stress) applied to the insulation around the area by evenly distributing the electric field of the area where the electric field is concentrated It is to provide a mold transformer that can minimize the occurrence of breakage.

A second object of the present invention is to provide a method for manufacturing a molded transformer that can minimize the occurrence of breakdown by minimizing the electric field stress (stress) applied to the insulator around the area by evenly distributing the electric field in the area where the electric field is concentrated. It is.

The first object of the present invention is a mold transformer,

An insulated conductor wound in a multi-layer in the longitudinal direction;

A semiconducting layer overlying at least one of the insulated conductors or one or more of the insulators, and evenly dispersing a concentrated electric field; And

It can be achieved by providing a mold transformer according to the present invention, which includes an insulating resin formed on the insulating conductor and the semi-conductive layer, forming an external shape of the mold transformer.

The second object of the present invention is a manufacturing method of a mold transformer,

A winding step of winding the insulating conductor in a multi-layer in the vertical direction on the outer circumferential surface of the winding;

Forming a semiconducting layer on at least one portion of the upper end or the lower end of the insulated conductor wound in the winding step;

Installing molds at predetermined intervals inside and outside in the radial direction of the semiconducting layer and the insulated conductor, respectively;

An insulating resin forming step of pouring a molten insulating resin between the semiconductive layer and the insulating conductor and the mold;

A curing step of curing the molten insulation resin; And

It can be achieved by providing a method of manufacturing a mold transformer comprising a; releasing step of removing the mold.

The mold transformer according to the present invention includes a semiconducting layer which is overlaid on at least one of the insulated conductors or at least one of the insulated conductors, and evenly distributes the concentrated electric field, so that the electric field is concentrated on a part of the insulated conductors. The effect of preventing the occurrence of dielectric breakdown can be obtained.

In the mold transformer according to the present invention, the insulating resin is composed of epoxy (EPOXY) to improve the flame resistance of the mold transformer has the effect of obtaining a mold transformer that can be installed in the room by removing the risk of fire and explosion.

In the mold transformer according to the present invention, the insulating conductor may be composed of an electrical conductor portion and an insulating coating layer of an insulating film or a nonwoven fabric wound on the electrical conductor portion to obtain an excellent electrical insulating property of the insulating conductor itself.

In the mold transformer according to the present invention, the semiconducting layer is composed of a plate formed of a polymer resin in which carbon black is mixed, thereby mixing the conductive carbon black with a polymer resin having electrical insulation to penetrate the semiconducting layer. It is effective to obtain a semiconducting layer having malleability.

Since the method of manufacturing a mold transformer according to the present invention has a semiconducting layer forming step of covering a semiconducting layer on at least one portion of an upper end or a lower end of an insulated conductor, an electric field is concentrated on a part of the insulated conductor in a mold transformer manufactured by the method. Therefore, there is an effect that can produce a mold transformer that can prevent the occurrence of insulation breakdown of the surrounding insulating resin.

In the method of manufacturing a mold transformer according to the present invention, since the semiconducting layer is overlaid on top of the two layers in the vertical direction of the upper end and the lower end of the insulated conductor, there is an effect that the semiconducting layer can be effectively installed at the site where electric field concentration occurs. .

The object of the present invention and the constitution and effects of the present invention to achieve the same will be more clearly understood by the following description of the preferred embodiment of the present invention with reference to the accompanying drawings.

First, the configuration and operation of a mold transformer according to an embodiment of the present invention will be described with reference to FIG. 1, which is a partial cutaway view and a chamber of the mold transformer according to an embodiment of the present invention.

In FIG. 1, the mold transformer 100 according to an exemplary embodiment of the present invention includes an insulating conductor 10, a semiconductive layer 20, and an insulating resin 30.

The insulated conductor 10 is formed by winding a multilayer in the vertical direction as shown in FIG. 1. The insulated conductor 10 may be constituted by an anticipated monolayer in a horizontal direction (that is, in the thickness direction of the mold transformer) in the mold transformer 100. Preferably, the insulating conductor 10 may include an electrical conductor portion and an insulating coating layer of an insulating film or nonwoven fabric wound on the electrical conductor portion. Therefore, the effect excellent in the electrical insulation of the insulating conductor 10 itself can be obtained.

The semiconducting layer 20 is formed on at least one insulating conductor 10 of the upper or lower portion of the insulating conductor 10, that is, two layers of the upper portion and the lower portion of the lower portion of the insulating conductor 10, that is, the insulating conductor portion to be relaxed. It is covered by the insulated conductors 10 of 10a and 10b, and evenly distributes a concentrated electric field. In this way, the upper and lower ends of the insulating conductor 10 are selected as the insulating conductor portions 10a and 10b to be relaxed, and electric fields are concentrated at edges, ends, and sharp portions of the electrical conductors to deteriorate the portions. And characteristics that cause partial discharge of the part.

The semiconductive layer 20 is a layer formed of a polymer resin in which carbon black is mixed. Since the polymer resin is electrically insulating and carbon black is conductive, the two materials are mixed to form a semiconductive layer having semiconductivity. Here, the carbon black may be configured and used as acetylene black or furnace black.

The insulating resin 30 has electrical insulation, forms the outline of the mold transformer 100, and is cast on the insulating conductor 10 and the semiconductive layer 20. Preferably, the insulating resin 30 is composed of epoxy (EPOXY, also known as epoxy resin). Since the insulating resin 30 is made of epoxy to improve the flame retardancy of the mold transformer 100, it is possible to obtain a mold transformer that can be installed indoors by minimizing the risk of fire and explosion.

Meanwhile, the operation of the mold transformer according to the present invention will be described.

In the mold transformer 100 according to the present invention, when an electric current is supplied to the insulating conductor 10 of the mold transformer 100, an electric field is generated around the insulating conductor 10. Such an electric field may be concentrated on the upper end or the lower end in the vertical direction in the mold transformer 100 of the insulated conductor 10.

However, in the mold transformer 100 according to the present invention, the semiconducting layer 20 is covered on at least one layer of the upper end or the lower end of the insulating conductor 10, that is, the insulating conductors 10a and 10b to be relaxed. Since the electric field concentrated in the corresponding part of (10) can be evenly distributed through the semiconducting layer 20, it is possible to prevent the occurrence of insulation breakdown of the insulating resin around the corresponding part of the insulating conductor 10.

Meanwhile, a method of manufacturing a mold transformer according to the present invention will be described with reference to FIGS. 2 and 3.

The method for manufacturing a mold transformer according to the present invention includes a winding step (ST1), a semiconducting layer forming step (ST2), a mold installation step (ST3), an insulating resin forming step (ST4), a curing step (ST5), and a release step (ST6). It is configured to include).

The winding step ST1 is performed by winding the insulated conductor 10 in a multi-layer in the vertical direction to the outer circumferential surface of the winding WS. In the winding step ST1, the insulating conductor 10 may be wound in a single layer in a horizontal direction, but may be wound in multiple layers without being limited to a single layer. Reference may be made to the upper left initial state of the progress state of the step indicated by the arrow in FIG. 3 after the execution of the winding step ST1.

The semiconducting layer forming step ST2 is performed by covering the semiconducting layer 20 on at least one portion of the upper end or the lower end of the insulated conductor 10 wound in the winding step ST1. Preferably, the semiconducting layer 20 is overlaid on top of the two layers in the vertical direction of the upper and lower ends of the insulating conductor 10, respectively. Here, covering the semiconductive layer 20 on the insulated conductor 10 may be achieved by adhering the semiconductive layer 20 to the insulated conductor 10 with an adhesive, for example. Referring to FIG. 3, the second progress state of the upper portion of the progress state of the step indicated by the arrow in FIG. 3 may be referred to after the semiconductive layer forming step ST2 is performed. The semiconducting layer 20 may be formed of a plate shape made of a polymer resin in which carbon black is mixed.

The mold installation step ST3 is performed by installing molds IS and OS at predetermined intervals inside and outside in the radial direction of the semiconducting layer 20 and the insulating conductor 10, respectively. Here, the winding WS used in the winding step ST1 is first removed and the inner mold IS is inserted into the space. The molds IS and OS consist of an inner mold IS and an outer mold OS. The reason for the spacing in the mold installation step ST3 is to pour the molten insulating resin into the gap portion. Reference may be made to the third progress state of the progress state indicated by the arrow in FIG. 3, that is, the right progress state in the middle of FIG. 3 after the mold installation step ST3 is performed.

In FIG. 3, the first 2nd progression state is shown as a perspective view, and three progression states are shown as cross-sectional views for easy understanding.

Next, the insulating resin forming step ST4 is performed by pouring the molten insulating resin 30 between the corresponding gap portion, that is, the semiconductive layer 20 and the insulating conductor 10 and the molds IS and OS. do. Here, the insulating resin 30 is preferably epoxy. The insulating resin forming step ST4 may refer to the fourth progress state, ie, the left progress state in the middle of FIG. 3, of the progress states indicated by the arrows in FIG. 3.

Next, the curing step ST5 is performed by curing the molten insulating resin 30. The corresponding step may refer to the fourth progress state, ie, the left progress state in the middle of FIG. 3, of the progress states indicated by the arrows in FIG. 3.

Next, the release step ST6 is performed by removing the mold, and after the release step ST6, a completed mold transformer can be obtained according to the method of manufacturing a mold transformer according to the present invention.

1 is a partial cutaway cross-sectional view of a mold transformer and a chamber according to an embodiment of the present invention.

2 is a process chart showing a process of a method of manufacturing a mold transformer according to the present invention;

3 is a manufacturing process state explanatory diagram showing a state in which a mold transformer is manufactured for each process of the manufacturing method of a mold transformer according to the present invention. The first two process states are shown in perspective view, and the three process states are shown as cross-sectional views.

* Explanation of symbols on the main parts of the drawings

10: insulated conductor 10a, 10b: insulation conductor to be relaxed

20: semiconducting layer 30: insulating resin

100: mold transformer IS: inner mold

OS: outside mold

Claims (11)

In a mold transformer, An insulated conductor wound in multiple layers in a vertical direction; A semiconducting layer evenly dispersing an electric field covered on the insulated conductor; And And an insulating resin formed on the insulating conductor and the semiconductive layer to form an external shape of the mold transformer. The method of claim 1, Mold insulation, characterized in that the insulating resin is composed of epoxy (EPOXY). The method of claim 1, The insulated conductor, Electrical conductor parts; And And an insulating coating layer of an insulating film or a nonwoven fabric wound on the electrical conductor portion. The method of claim 1, The semiconducting layer is a mold transformer, characterized in that the layer formed of a polymer resin mixed with carbon black (Carbon Black). The method of claim 4, wherein The carbon black, Mold transformer, characterized in that consisting of acetylene black (Acethylene Black) or Furnace Black (Furnace Black). The method of claim 1, The semiconducting layer, And a semiconducting layer overlying at least one of the insulating conductors of the insulating conductor. In the manufacturing method of the mold transformer, A winding step of winding the insulating conductor in a multi-layer in the vertical direction on the outer circumferential surface of the winding; A semiconducting layer forming step of covering a semiconducting layer on the insulated conductor wound in the winding step; And an insulating resin forming step of adding an insulating resin surrounding the semiconductive layer and the insulating conductor. The method of claim 7, wherein In the winding step, the insulating conductor is a method of manufacturing a mold transformer, characterized in that the winding in a single layer in the horizontal direction. The method of claim 7, wherein The semiconducting layer is a method of manufacturing a mold transformer, characterized in that the upper portion of the upper and lower ends of the insulated conductor is overlaid on each of the two layers. The method of claim 7, wherein The insulating resin is a manufacturing method of a mold transformer, characterized in that the epoxy. The method of claim 7, wherein The semiconducting layer is a method of manufacturing a mold transformer, characterized in that consisting of a polymer resin mixed with carbon black (Carbon Black).

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