JP6965623B2 - Winding structure, coils, transformers and rotating machines - Google Patents

Description

The present invention relates to winding structures, coils, transformers and rotating machines.

In electrical equipment represented by a transformer, the conductor of a coil having a high voltage is sealed with a solid insulator such as epoxy resin. However, it is difficult to seal the conductor so that there are no voids around it. When an electric device is operated with a gap around the conductor, a partial discharge occurs due to a potential difference generated between the coils, which causes a problem that the long-term reliability of the electric device is lowered.

In order to solve such a problem, in order to reduce the number of voids, it has been proposed to increase the impregnation property of the resin into the voids around the conductor in the method for manufacturing the resin molded coil (for example, Patent Document 1). reference).

As described in Patent Document 1, in a multiple coil in which conductors are wound around the outer periphery of a core portion so as to form a plurality of layers, a potential difference is obtained between the laminated conductors. An interlayer insulating material is interposed between each layer to insulate this potential difference. Therefore, a gap is formed between the conductor and the interlayer insulating material. When the number of turns of the conductor was around 100, it was not easy to impregnate the highly viscous thermosetting resin inward in the axial direction to reduce the voids.

Therefore, in the method for manufacturing a resin molded coil described in Patent Document 1, an interlayer insulating material (paper) having a plurality of communication holes for passing a liquid thermosetting resin is interposed between each layer of the coil to generate heat. The curable resin invades the inside of the coil through the communication holes of the interlayer insulating material of the outermost layer, and further impregnates in the radial direction of the coil through the communication holes of the interlayer insulating material of each inner layer in order. It flows into the gap between the two. As a result, the number of voids is further reduced as compared with the impregnation of the thermosetting resin inward in the axial direction.

Japanese Unexamined Patent Publication No. 2016-207741

On the other hand, from the viewpoint of ensuring the long-term reliability of electrical equipment, it is required to further suppress the generation of partial discharge. According to the technique described in Patent Document 1, it is possible to reduce the voids around the windings to some extent, but it is extremely difficult to completely eliminate them, and it is an industrially effective means from the viewpoint of manufacturing cost. Not always.

The present invention has been made in view of such a problem, and the winding structure, coil, and winding structure of an electric device capable of effectively suppressing the generation of partial discharge due to the potential difference generated in the void around the winding. One of the purposes is to provide transformers and rotating machines.

One aspect of the winding structure in the present invention is a winding structure for an electric device, which comprises a conductive wire, an insulating layer arranged on the outer periphery of the conductive wire and made of an insulating resin, and the insulating layer. A first conductive layer arranged on the outer periphery and having a conductive material added to the insulating resin, and a second conductive layer having a conductive material added to the insulating resin arranged on the outer periphery of the first conductive layer. And, and the content of the conductive material is lower than that of the first conductive layer .

With this configuration, by setting the potential of the first conductive layer to a neutral point potential or a ground potential, the first conductive layer takes a potential at which no current flows. As a result, the potential difference between the resin layer and the neutral point potential or the ground potential, or the potential difference between the resin layer and the resin layer of the adjacent winding can be kept low, so that the potential difference generated in the void around the winding is reduced to 300 V or less. It can be suppressed and the occurrence of partial discharge can be suppressed.

In one aspect of the winding structure in the present invention, it is preferable that the first conductive layer and the conductive material added to the second conductive layer have the same composition.

In one aspect of the winding structure in the present invention, the conductive material is preferably graphene or carbon nanotubes or a mixture thereof.

In one aspect of the winding structure in the present invention, it is preferable that the thickness of the insulating layer is larger than the thickness of the second conductive layer.

One aspect of the coil in the present invention is characterized in that a winding having the winding structure described above is used.

One aspect of the coil in the present invention is characterized in that a winding having the winding structure described above is wound so that the second conductive layers come into contact with each other.

In one embodiment of the coil in the present invention is preferably provided with a potential before Symbol first conductive layer a connection for the neutral point potential or ground potential.

One aspect of the transformer in the present invention is characterized in that the coil described above is used and the potential of the first conductive layer is a three-phase AC type neutral point potential.

In one aspect of the rotating machine of the present invention, the coil described above is used, and the potential of the first conductive layer is equal to the potential of the slot around which the winding used for the coil is wound together with the coil. It is characterized by that.

One aspect of the transformer in the present invention is characterized in that the coil described above is used and the potential of the first conductive layer is equal to the surface potential of the coil.

According to the present invention, it is possible to provide a winding structure, a coil, a transformer and a rotating machine of an electric device capable of effectively suppressing the generation of partial discharge due to a potential difference generated in a gap around a winding. ..

It is a schematic diagram which shows the winding structure which concerns on this embodiment. It is a schematic diagram which shows the coil using the winding which has the winding structure which concerns on this embodiment. It is a schematic diagram which shows the part where the folded-back portion of the winding is close to each other in the coil using the winding which has the winding structure which concerns on this embodiment. It is a schematic diagram which shows the end connection structure applied to the winding structure which concerns on this embodiment. It is a schematic diagram which shows an example of the neutral point to which the winding having the winding structure which concerns on this embodiment is connected.

Hereinafter, the winding structure for the electric device according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings. The winding structure according to the present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the purpose.

In the present embodiment, a transformer and a rotating machine will be described as an example of an electric device, but the present embodiment is not limited thereto.

<Wounding structure>
FIG. 1 is a schematic view showing a winding structure according to the present embodiment. As shown in FIG. 1, the winding structure 1 includes a conductive wire (core wire) 2.

In the present embodiment, the conductive wire 2 is a wire obtained by linearly stretching a good electric body such as copper or a copper alloy, and is preferably a bare electric wire having no coating. More specifically, the conductive wire 2 is a metal conducting wire such as a copper wire or a copper alloy wire having a diameter of 0.5 to 8 mm.

An insulating layer 3 is provided on the outer periphery of the conductive wire 2. The insulating layer 3 is made of a thermosetting insulating resin such as polyamide-imide and polyurethane.

The thickness of the insulating layer 3 is not particularly limited, but for example, insulation is maintained so that insulation with the first conductive layer 4 (described later) is maintained even when a high voltage of 2000 V is applied to the conductive wire 2. It is appropriately selected in consideration of the type of sex resin and the like.

The first conductive layer 4 is arranged on the outer periphery of the insulating layer 3. The first conductive layer 4 can be obtained, for example, by adding a conductive material to the insulating resin used for the insulating layer 3 to make it conductive.

The conductive material is, for example, a carbon-based conductive material. The carbon-based conductive material is, for example, carbon powder, graphene, or carbon nanotubes or a mixture thereof. Of these, graphene, carbon nanotubes, or a mixture thereof is preferable. This is because the tensile strength and flexibility required for manufacturing the coil can be increased as compared with carbon powder and the like.

By adding a carbon-based conductive material to polyamide-imide or polyurethane, which is an insulating resin as a base material, for example, 15% or more and 60% or less by weight, the layer made of the insulating material is imparted with conductivity. can do.

The thickness of the first conductive layer 4 is not particularly limited, but it is desirable to keep the thickness to 1/20 or less of the winding diameter for the purpose of preventing cracks during winding and bending. Further, in order to ensure conductivity, it is desirable that the first conductive layer 4 is configured to have a thickness of 5 micrometers or more.

Further, a resin layer 5 is arranged as an outermost layer on the outer periphery of the first conductive layer 4. The resin layer 5 may be an insulating layer made of an insulating resin, or may be a conductive layer in which a conductive material is added to the insulating resin (hereinafter, referred to as a second conductive layer).

As the insulating resin used for the resin layer 5, the same insulating resin as the insulating resin constituting the insulating layer 3 and the first conductive layer 4 can be used.

Further, in order to make the resin layer 5 a second conductive layer, for example, as described in the first conductive layer 4, a conductive material is added to the insulating resin to impart conductivity.

When the resin layer 5 is used as the second conductive layer, the second conductive layer preferably has a lower content of the conductive material than the first conductive layer 4. The resin layer 5 is more than the first conductive layer 4 from the viewpoint of preventing the first conductive layer 4 from cracking due to scratching when winding the winding around the core of the coil and making the winding easier to handle. This is because it is preferable that the toughness and flexibility are excellent.

The thickness of the resin layer 5 is not particularly limited, but it is preferably thinner than the thickness of the insulating layer 3, and particularly preferably 1/3 or less of the thickness of the insulating layer 3. In other words, the thickness of the insulating layer 3 is preferably larger than the thickness of the resin layer 5.

<All-solid-state insulated winding>
An insulating structure made of a solid in which all layers for insulation do not contain voids, such as the winding structure 1, is called all-solid-state insulation. In all-solid insulation, since air is not included, all potential differences are applied to the solid. It is different from the composite insulation (existing solid insulation) to which is added. Such an insulating structure is particularly useful when a high voltage (eg 2000V) is applied to the winding.

<Manufacturing method of winding>
Hereinafter, an example of a method for manufacturing a winding having a winding structure 1 will be described. First, as the conductive wire 2, a copper wire stretched to a predetermined diameter and formed into a wire shape is sent out from one reel and wound up on the other reel facing each other. A processing line will be installed between these reels.

In the processing line, three coating treatment portions are continuously arranged corresponding to the insulating layer 3, the first conductive layer 4, and the resin layer 5. One coating treatment unit contains a molten resin (insulating resin or insulating resin to which a conductive material is added) (hereinafter referred to as a resin solution), and a solution in which a traveling copper wire is immersed in the resin solution. It is provided with a tank and a drying furnace for drying the copper wire coated with the molten resin drawn from the solution tank.

In each of the three coating treatment portions, a molten resin is applied to the surface of the copper wire and dried to form a coating layer. As a result, the winding having the winding structure 1 can be continuously manufactured.

The method for manufacturing a winding having the winding structure 1 according to the present embodiment is not limited to the above-mentioned manufacturing method. For example, instead of forming the coating layer by immersion, the coating layer may be formed by using an extruder.

<Coil>
FIG. 2 is a schematic view showing a coil using a winding having a winding structure 1 according to the present embodiment. As shown in FIG. 2, in the coil 10, the winding 11 having the winding structure 1 is formed into a plurality of layers (4 layers in FIG. 2, but not limited to) on the outer periphery of the core portion 12 made of an insulating material. It is a wound multiple coil. Further, in the coil 10, an interlayer insulating material 13 is interposed between the layers.

In the coil 10 shown in FIG. 2, a wedge-shaped gap is formed at a position where the winding 11 and the winding 11 come into contact with each other. In such a gap, the distance between the winding 11 and the winding 11 changes steplessly, so that a portion having the most discharge distance (atmospheric pressure, 8 to 9 μm at room temperature) is likely to be formed in this portion. Discharge is likely to occur.

Further, in the coil 10 shown in FIG. 2, for example, in the portion where the folded portion of the winding 11 is close to each other (the portion surrounded by the broken line in FIG. 2), the coil 10 is connected to the winding 11 adjacent to each other via the interlayer insulating material 13. The potential difference between the winding 11 and the winding 11 has a potential difference corresponding to the number of turns for two layers.

FIG. 3 is a schematic view showing a portion where the folded portion of the winding 11 is close to each other in the coil 10 using the winding 11 having the winding structure 1 according to the present embodiment. As shown in FIG. 3, when there is a potential difference of 350 V or more between the potentials of the two adjacent windings 11 and the potential of the second layer winding 11 in the folded portion, the windings 11 and the windings 11 Alternatively, there is a high possibility that a discharge will occur in a wedge-shaped gap (indicated by the symbol X in FIG. 3) between the winding 11 and the interlayer insulating material 13.

Therefore, in the winding structure 1 according to the present embodiment, the first conductive layer 4 is arranged on the outer periphery of the conductive wire 2 (see FIG. 1) via the insulating layer 3, and the potential of the first conductive layer 4 is arranged. Is provided with a neutral point connecting portion 21, which is an example of the connecting portion of the present invention, in which the potential is set to the neutral point potential or the ground potential. In FIG. 3, the symbol O indicates a neutral point potential or a ground potential.

By setting the potential of the first conductive layer 4 to the neutral point potential or the ground potential in this way, the first conductive layer 4 takes a potential at which no current flows. As a result, the potential difference between the conductive wire 2 and the first conductive layer 4 can be kept low, so that the potential difference generated in the gap X of the wedge-shaped gap X can be suppressed to 300 V or less, and the occurrence of partial discharge can be suppressed.

In electrical equipment, the neutral point is an electrically neutral state, and the neutral point potential is a potential through which no current flows. On the other hand, the ground potential is not necessarily an electrically neutral state, and may be a potential through which a current flows. In the present embodiment, the ground potential means a case where no current flows.

In order to seal all wedge-shaped gaps with resin in order to suppress partial discharge, large-scale equipment for vacuum impregnation is required to impregnate the high-viscosity insulating resin.

Further, in order to suppress partial discharge, it is effective to increase the cross-sectional area of the conductive wire 2 and allow a large amount of current to flow, but the material cost of the winding 11 increases.

On the other hand, according to the winding structure 1 (see FIG. 1) according to the present embodiment, the occurrence of partial discharge can be prevented without necessarily performing resin sealing, so resin sealing is omitted. As a result, long-term reliability of electrical equipment can be ensured without increasing the material cost of the winding 11 while significantly reducing the manufacturing cost. Alternatively, by resin sealing, for example, even if the voids existing in the wedge-shaped gaps described above remain, the occurrence of partial discharge can be suppressed, so that the long-term reliability of the electrical equipment can be suppressed without increasing the manufacturing cost and the material cost. Can be secured.

<Neutral point connection>
Next, a specific example of the above-mentioned neutral point connecting portion 21 (see FIG. 3) will be described.

First, the neutral point connecting portion 21 is formed by, for example, a contact electrically connected to the first conductive layer 4 and a conductive member electrically connecting the contact with a neutral point or a grounding point of an electric device. Can be configured.

(End connection structure)
FIG. 4 is a schematic view showing an end connection structure applied to the winding structure 1 according to the present embodiment. As shown in FIG. 4, the insulating layer 3, the first conductive layer 4, and the resin layer (outermost layer) 5 (hereinafter, also simply referred to as coating) are removed from the end of the winding 11 at a predetermined length. , The conductive wire 2 is exposed. Hereinafter, the portion of the winding 11 from which the coating has been removed will be referred to as a coating removal portion. An end connection structure 30 is formed at the end of the winding 11 in such a state.

As shown in FIG. 4, the end connection structure 30 is composed of, for example, an insulating block 31 and a connecting ring 32 embedded in the insulating block 31.

Although the insulating block 31 is made of an insulating resin, it is possible to select one having a higher hardness at the time of curing than the insulating resin constituting the insulating layer 3, the first conductive layer 4, and the resin layer 5. It is preferable from the viewpoint of processability of tapering of the coating, which will be described later.

The insulating block 31 is a portion that is the end of the winding 11 and has a coating from one end face (the left end face shown in FIG. 4) to a predetermined depth from the other end face (the right end face shown in FIG. 4). An insertion hole 33 into which (hereinafter, referred to as a covering portion) is inserted is formed. The inner diameter of the insertion hole 33 is slightly larger than the outer diameter of the covering portion.

Further, a tapered hole 34 is formed from the tip of the insertion hole 33 (the end on the right side shown in FIG. 4) to a predetermined depth toward the other end surface of the insulating block 31. The inner diameter of the rear end (the left end shown in FIG. 4) of the tapered hole 34 substantially coincides with the outer diameter of the insulating layer 3. On the other hand, the inner diameter of the tip of the tapered hole 34 (the end on the right side shown in FIG. 4) is slightly larger than the outer diameter of the conductive wire 2. Therefore, the inner diameter of the tapered hole 34 gradually decreases from the rear end to the front end.

Further, in the insulating block 31, a funnel-shaped enlarged diameter portion 35 is formed from the tip of the tapered hole 34 to the other end surface of the insulating block 31. The inner diameter of the rear end (the left end shown in FIG. 4) of the enlarged diameter portion 35 substantially coincides with the inner diameter of the tapered hole 34. On the other hand, the inner diameter of the tip of the enlarged diameter portion 35 (the end on the right side shown in FIG. 4) is not particularly limited, but is larger than the inner diameter of the rear end. Therefore, the inner diameter of the enlarged diameter portion 35 gradually increases from the rear end toward the front end.

In the insulating block 31, a connecting ring 32 is embedded near the boundary between the insertion hole 33 and the tapered hole 34. The connecting ring 32 is made of a metal conductor, for example copper or a copper alloy. Edges 32a projecting inward in the radial direction are continuously formed on the inner peripheral surface of the connecting ring 32. The inner diameter at the tip of the edge 32a is substantially the same as the outer diameter of the first conductive layer 4 of the winding 11.

Further, a contact point for passing a lead wire 36 through a predetermined portion of the insulating block 31, in the present embodiment, the lower side shown in FIG. 4, and soldering the end of the lead wire 36 to the connection ring 32 with solder 37. A hole 38 is formed. The method of connecting the lead wire 36 to the connection ring 32 is not limited to soldering, and other methods may be used.

The connection ring 32 can be embedded, for example, as follows. First, a heat-meltable insulating resin is selected as the material of the insulating block 31. Then, when the insulating block 31 is injection-molded using the mold, the connection ring 32 is installed at a predetermined position of the mold.

In the end connection structure 30 having the above-described configuration, as shown in FIG. 4, the decoating portion of the winding 11 is expanded from one end side of the insulating block 31 to the insertion hole 33, the tapered hole 34, and the expansion. The end of the winding 11 is inserted into the insulating block 31 so as to sequentially pass through the diameter portion 35, reach the other end side, and protrude.

Then, first, the resin layer (outermost layer) 5 is removed by hitting the edge 32a of the connecting ring 32 at the boundary between the coating-removing portion and the coating portion of the winding 11, that is, the end face of the coating. Further, when the winding 11 is inserted, the end surface of the coating is first a corner portion 33a formed by the tip end portion of the insertion hole 33 formed in the insulating block 31 and the opening portion on the rear end side of the taper hole 34. Hits. The hardness of the insulating resin (base material) constituting the first conductive layer 4 is lower than that of the insulating resin constituting the insulating block 31. Further, the inner diameter of the rear end of the tapered hole 34 is substantially the same as the outer diameter of the insulating layer 3. Therefore, when the winding 11 is further inserted, the first conductive layer 4 of the coating is removed by the corner portion 33a.

The removed coating goes out of the insulating block 31 through the contact hole 38.

Next, the first conductive layer 4 is removed, and the winding 11 with the insulating layer 3 exposed is pushed into the tapered hole 34. The hardness of the insulating resin constituting the insulating layer 3 is lower than that of the insulating resin constituting the insulating block 31. Therefore, the insulating layer 3 is deformed and tapered along the inner surface of the tapered hole 34. This is called coating taper.

By inserting the end of the winding 11 into the insulating block 31 in this way, the resin layer 5 and the first conductive layer 4 are removed and the coating is tapered. Further, the edge 32a of the connecting ring 32 and the first conductive layer 4 are in contact with each other. As a result, continuity between the connecting ring 32 and the first conductive layer 4 can be obtained.

Due to the tapering of the coating, the insulating layer 3 and the insulating block 31 are in close contact with each other, so that it is difficult for air to enter and voids are unlikely to occur, so that partial discharge at this portion can be suppressed.

From the viewpoint of workability of removing the resin layer 5 and the first conductive layer 4 and tapering the coating, the insertion of the end of the winding 11 into the insulating block 31 is performed by, for example, press-fitting or tightening to apply a sufficient external force. It is desirable to do it while adding.

After that, as shown in FIG. 4, the enlarged diameter portion 35 of the insulating block 31 is closed and the conductive wire 2 of the coating removal portion is wrapped and fixed with the varnish-like insulating adhesive 39.

With the end connection structure 30 having the above-described configuration, at the end of the winding 11, the connection ring 32, which is an example of a contact, and the lead wire 36, which is an example of a conductive member, are interposed with the first conductive layer 4. An electrical connection with a neutral or ground point can be established.

Further, when the conductive wire 2 and the first conductive layer 4 are in contact with air at the end of the winding 11, for example, when a high voltage of 2000 V is applied to the conductive wire 2, if the distance between the two is short, the insulation by air is not sufficient. Will cause a discharge. In the end connection structure 30, the distance between the conductive wire 2 and the first conductive layer 4 is secured by the depth of the tapered hole 34. Further, the insulating layer 3 located in the tapered hole 34, the insulating block 31 in the vicinity of the tapered hole 34, and the insulating adhesive 39 can provide solid insulation between the conductive wire 2 and the first conductive layer 4. As a result, even if a high voltage is applied to the conductive wire 2, it is possible to suppress the occurrence of electric discharge with the first conductive layer 4.

The end connection structure 30 is particularly useful when the resin layer 5 is an insulating layer because the resin layer (outermost layer) 5 can be peeled off and the first conductive layer 4 can be brought into contact with the connection ring 32. Even when the resin layer 5 is a second conductive layer containing a conductive material, it is beneficial from the viewpoint of tapering the resin and workability of connecting the neutral point with the connecting ring 32.

The end connection structure 30 as described above is particularly effective in suppressing partial discharge in the end connection structure 30 itself in the coil 10 to which a high voltage is applied. However, the end connection structure for a coil using a winding having the winding structure of the present invention is not limited to this.

(Neutral point connection using surface contact)
Next, the neutral point connection portion utilizing the contact of the surface of the resin layer (outermost layer) 5 will be described. In this case, the resin layer 5 is a second conductive layer obtained by adding a conductive material to the insulating material. In the following description, the resin layer 5 will be referred to as the second conductive layer 5.

The conductive materials added to the first conductive layer and the second conductive layer may have the same composition or different compositions, but the same composition is preferable.

Like the coil 10 shown in FIG. 2, in the multiple coil, the winding 11 is wound around the outer circumference of the core portion 12 along the axial direction while being in contact with each other. At this time, the second conductive layer 5, which is the outermost layer, comes into contact with each other between the adjacent windings 11. When the coil 10 is viewed from the cut surface along its axial direction (see FIG. 2), as shown in FIG. 3, electricity is sequentially passed through the contact points (A) between the second conductive layers 5 of the adjacent windings 11. Becomes conductive.

Therefore, the winding 11 is repeatedly wound around the outer periphery of the core portion 12 (for example, 100 turns), and the winding 11 located on the innermost side in the radial direction of the coil 10 and the winding 11 located on the outermost side are conductive. Even if the electrical conduction distance through the wire 2 becomes extremely long, the electrical conduction distance through the contacts (A) between the adjacent second conductive layers 5 can be ensured at the shortest. The potential difference between the second conductive layer 5 of the winding 11 located inside the coil 10 in the radial direction and the winding 11 located outside increases with the conduction distance of electricity through the conductive wire 2. However, according to the neutral point connection using surface contact, the potential of the second conductive layer 5 of the winding 11 located inside in the radial direction of the coil is set to the potential of the second conductive layer 5 of the winding 11 located outside. Can be approached to the potential of (hereinafter referred to as surface potential).

The second conductive layer 5 is provided directly on the peripheral surface of the first conductive layer 4 (see FIG. 1). Therefore, the first conductive layer 4 is equal to the surface potential of the coil 10 via the second conductive layer 5 of the adjacent windings 11 at any position in the radial direction of the coil 10. It becomes an electric potential. Further, by providing a neutral point connecting portion 21 that makes the potential of the second conductive layer 5 of the winding 11 on the surface of the coil 10 a neutral point potential or a ground potential (indicated by the symbol O in FIG. 2), the second 1 The potential of the conductive layer 4 can be a neutral point potential or a ground potential. As a result, partial discharge in the coil 10 can be suppressed.

Here, a multiple coil used in a transformer has been described as an example, but in a rotating machine, a rotor in which a winding is repeatedly wound in a slot also has a similar problem, and the winding according to the present embodiment has the same problem. This can be solved by using wire 11 and applying a neutral point connection utilizing surface contact.

<Application to electrical equipment>
Hereinafter, a case where the coil 10 using the above-mentioned winding 11 is used for a transformer and a rotating machine, which are examples of electric devices, will be described.

Partial discharge has a small individual energy, but if it continues for a long time, it produces ozone, and the insulating resin used to coat the windings is molecularly cleaved by oxidation, the insulation is reduced, short circuits occur, and transformers and rotation occur. It leads to damage to the machine.

As for the transformer, a multi-cylindrical coil as described with reference to FIG. 2 is mainly used. Therefore, as described above, partial discharge is likely to occur at a portion where the folded portions of the coil windings are close to each other.

On the other hand, as for the rotating machine, for example, the winding is wound around a comb-shaped slot (iron core) for use. Therefore, a partial discharge may occur between the coil and the slot.

Therefore, by using the winding 11 (see FIG. 2) having the winding structure 1 as shown in FIG. 1 and setting the potential of the first conductive layer 4 to the intermediate point potential or the ground potential, the transformer and the rotating machine can be used. Damage can be prevented.

In the transformer, for example, the first conductive layer 4 (see FIG. 1) of the winding 11 used for the coil 10 (see FIG. 2) is connected to the neutral point of the transformer via the neutral point connecting portion 21. Then, the potential of the first conductive layer 4 is set as the neutral point potential.

In this case, as described with reference to FIG. 2, the neutral point connecting portion 21 is the first winding 11 forming the outermost layer of the coil 10 so that the surface potential of the coil 10 becomes the neutral point potential. 2 The conductive layer 5 is connected to the neutral point of the transformer. In addition, electrical continuity is ensured through the contacts of the adjacent second conductive layers 5 in sequence. Further, electrical contact with the first conductive layer 4 which is in direct contact with the second conductive layer 5 is ensured. As a result, the potential of the first conductive layer 4 can be set to the surface potential of the coil 10, that is, the neutral point potential.

FIG. 5 is a schematic view showing an example of a neutral point to which the winding 11 having the winding structure 1 according to the present embodiment is connected. FIG. 5 shows three-phase coils 51, 52, and 53 used in a transformer. The coils 51, 52, and 53 are a U-phase coil, a V-phase coil, and a W-phase coil, respectively. The three-phase coils 51, 52, and 53 are Y-connected to the neutral point O of the three-phase AC type with a phase difference of 120 degrees from each other. The potential of the neutral point O is electrically neutral and is a potential at which no current flows. Therefore, the second conductive layer 5 (see FIG. 2) of the winding 11 forming the outermost layer of the coil 10 is connected to the neutral point O of the three-phase AC type as shown by the one-point chain line in FIG. By doing so, the potential of the first conductive layer 4 can be set to a three-phase AC type neutral point potential.

Regarding the rotating machine, when the winding has a winding structure 1 (see FIG. 1) in the slot and the resin layer (outermost layer) 5 is the second conductive layer 5, electricity is generated at the contact point between the winding and the slot. Conduction can be ensured. Therefore, since the first conductive layer 4 is electrically connected to the slot via the contacts of the adjacent second conductive layers 5 in sequence, the potential of the first conductive layer 4 is the potential of the slot (hereinafter referred to as the slot). It becomes equipotential with (described as electric potential). Further, by providing a neutral point connection portion that sets the surface potential of the coil 10 to a neutral point potential or a ground potential (indicated by the symbol O in FIG. 2), the potential of the first conductive layer 4 becomes a neutral point potential or a neutral point potential. Can be ground potential. As a result, partial discharge in the coil can be suppressed.

As described above, according to the winding structure 1 (see FIG. 1) according to the present embodiment, the potential of the first conductive layer 4 is set to the neutral point potential or the ground potential, so that the first conductive layer is formed. 4 comes to take a potential at which no current flows. As a result, the potential difference between the conductive wire 2 and the first conductive layer 4 can be kept low, so that the potential difference generated in the void can be suppressed to 300 V or less, and the occurrence of partial discharge can be suppressed.

Since the first conductive layer 4 is formed by adding a conductive material to an insulating resin, it has no voids and is excellent in flexibility, so that it is unlikely to cause partial discharge.

It is also conceivable that the first conductive layer 4 is formed of a metal film formed by plating, sputtering, or the like. However, the metal coating may crack due to bending or tension when winding the winding around the core of the coil, or may break due to a partial increase in thermal resistance. Such cracks and breaks cause voids, and it is technically extremely difficult to realize a layer without voids, which is not realistic.

Further, the resin layer 5 is provided on the peripheral surface of the first conductive layer 4. The resin layer 5 prevents the first conductive layer 4 from cracking due to scratching when the winding 11 is wound around the core portion 12 (see FIG. 2) of the coil 10, and the resin layer 5 itself also has voids. Since it is also excellent in flexibility, the toughness of the winding 11 is further enhanced, and it is easy to handle, and the workability of manufacturing the coil 10 is not deteriorated.

Further, when the winding 11 is repeatedly wound in a multiple coil or the like such as the coil 10 shown in FIG. 2 by forming the resin layer 5 as a second conductive layer 5 in which a conductive material is added to an insulating resin. The current density and thermal resistance can be reduced by bringing the second conductive layers 5 of the adjacent windings 11 into contact with each other.

Further, in a transformer and a rotating machine to which a coil using a winding having a winding structure 1 is applied, the potential of the first conductive layer 4 is set to a neutral point potential or a ground potential so that the first conductive layer 4 is formed. It is possible to prevent a large amount of current from flowing and prevent damage to the first conductive layer 4.

The present invention is not limited to the above embodiment, and can be modified in various ways. In the above embodiment, the size and shape of the members and the like shown in the accompanying drawings are not limited to this, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it can be appropriately modified and implemented as long as it does not deviate from the scope of the object of the present invention.

For example, in the above embodiment, the case where the first conductive layer 4 (see FIG. 1) is connected to the neutral point of the three-phase AC type transformer has been described with reference to FIG. The first conductive layer 4 may be connected to the intermediate potential of the AC power cable and the DC two-wire type power cable.

According to the winding structure of the present invention, it is possible to effectively suppress the generation of partial discharge due to the potential difference generated in the void around the winding, and it is particularly preferably used for transformers and rotating machines. be able to.

1 Winding structure 2 Conductive wire 3 Insulation layer 4 First conductive layer 5 Resin layer (second conductive layer)
10, 51, 52, 53 Coil 11 Winding 12 Core 13 Interlayer insulation 21 Neutral point connection (connection)
30 End connection structure 31 Insulation block 32 Connection ring 39 Insulation adhesive

Claims (10)

It is a winding structure for electrical equipment,
Conductive wire and
An insulating layer made of an insulating resin, which is arranged on the outer circumference of the conductive wire,
A first conductive layer arranged on the outer periphery of the insulating layer and having a conductive material added to the insulating resin,
A second conductive layer in which a conductive material is added to the insulating resin arranged on the outer periphery of the first conductive layer, and
Equipped with
A winding structure characterized in that the content of the conductive material is lower than that of the first conductive layer. The winding structure according to claim 1, wherein the first conductive layer and the conductive material added to the second conductive layer have the same composition. The winding structure according to claim 1 or 2, wherein the conductive material is graphene, carbon nanotubes, or a mixture thereof. The winding structure according to any one of claims 1 to 3, wherein the thickness of the insulating layer is larger than the thickness of the second conductive layer. A coil according to any one of claims 1 to 4, wherein a winding having the winding structure is used. A coil characterized in that a winding having the winding structure according to any one of claims 1 to 5 is wound so that the second conductive layers come into contact with each other. The coil according to claim 5 or 6, further comprising a connecting portion for setting the potential of the first conductive layer to a neutral point potential or a ground potential. A transformer according to any one of claims 5 to 7, wherein the potential of the first conductive layer is a three-phase AC neutral point potential. The coil according to any one of claims 5 to 7 is used, and the potential of the first conductive layer is equal to the potential of the slot around which the winding used for the coil is wound together with the coil. A rotating machine characterized by that. A transformer according to claim 6, wherein the coil is used, and the potential of the first conductive layer is equal to the surface potential of the coil.

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