JPH0471346A - High-tension rotating machine coil - Google Patents

Abstract

PURPOSE:To prevent damage due to discharge by arranging a crape like semiconductive material outside a mica-tape-wound layer, forming a coil not impregnated and unifying the coil not impregnated and a core through an impregnating resin. CONSTITUTION:A crape like semiconductive material 7 is disposed onto a mica- tape-wound layer 2 formed onto a strand conductor bundle 1, and used as an external corona preventive layer. The crape like semiconductive material 7 is arranged in such a manner that the tape-shaped crape like semiconductive material 7 is wound on the mica-tape-wound layer 2 as shown in the figure, end corona prevention is executed, and a coil not impregnated is inserted into a core 4. The crape like semiconductive material 7 is deformed in response to a clearance on the side face of the core. A thermosetting resin is held in the crape like clearance by impregnating the clearance with the resin, and the mica-tape-wound layer 2 and the core 4 are unified through the crape like semiconductive material 7 and the impregnating resin. Accordingly, a coil and the core are fast stuck, thus preventing damage due to discharge.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to insulation of stator coils of high-voltage rotating machines.

[Conventional technology]

Insulation of stator coils of high-voltage rotating machines such as 3kV abnormal induction motors and generators can be broadly classified into two types. 1
One is prepreg insulation in which a certain amount of resin is held in advance in the mica tape that forms the ground insulating layer, the tape is wrapped around a bundle of wire conductors, and then heated to form the ground insulating layer. The other method is to wrap a mica tape containing almost no resin on a bundle of bare wire conductors, then vacuum the mica tape and impregnate the mica tape with pressure, and then harden the resin to form the ground insulation layer. There is impregnation. In addition, there are two methods for manufacturing resin-impregnated insulation: one method for manufacturing each single coil, and another method for manufacturing resin-impregnated insulation.
Before pressure impregnation, place the unimpregnated coil into the core slot and connect the coil lead wire. There is so-called total impregnation, in which crossover wires and the like are connected to form unimpregnated stator windings, followed by vacuum evacuation and pressure impregnation in a vacuum chamber, and rough heating hardening. FIG. 3 is a cross-sectional view of a conventional high voltage coil with full impregnation insulation. In Figure 3, mica tape, which is made by laminating mica to a backing material such as glass cloth film or nonwoven fabric, is wound around a bundle of wire conductors 1, which is made by bundling wire conductors and forming them into a hexagonal shape, according to the voltage class, for ground insulation. A mica tape-wrapped layer 2 is formed. At this stage, the mica tape contains only the bonding resin. After that, in order to prevent partial discharge and thrower I discharge that occur between the ground insulating layer 2 and the iron core, a semiconductive tape or sheet is wound as an external corona prevention layer 3 in an area that is approximately the same as the iron core slot length. be done. Thereafter, an end corona prevention layer is further applied to the end of the outer corona prevention layer 3. The unimpregnated hexagonal coil thus prepared is inserted into the core slot, lead wires, crossover wires, etc. are connected to form the stator winding, and then the core and coil are integrated and placed in a vacuum chamber under vacuum. An example of full-impregnation insulation is to pressure-impregnate and harden a thermosetting epoxy resin to obtain the ground insulation N2 of the stator coil. With this fully impregnated insulation, the ground insulating layer is hardened and molded in advance, and the completely completed stator coil with the insulation dimensions adjusted is not inserted into the core slot, so the contact condition between the external corona prevention layer and the core is important. becomes. For example, if the width of the unimpregnated hexagonal coil inserted into the core slot is extremely narrow compared to the slot width of the core, the result will be as shown in FIG. 4. FIG. 4 is a diagram showing a state in which the high voltage coil of FIG. 3 is inserted into the iron core. In other words, iron core thrower) 4a
A coil consisting of a wire conductor bundle 1, a ground insulation layer 2 and an external anti-corona layer 3 is inserted into the coil in a deformed form,
The contact area between the external corona prevention layer 3 and the iron core 4 is reduced, and the iron core 4 and the coil are not integrated in a normal manner. If the stator coil is formed in such a state, the external corona prevention layer 3 may be locally heated and burnt out, or the coil may vibrate due to electromagnetic vibration during long-term operation, causing the iron core 4 and the external corona prevention layer to become damaged. There is a risk that slot discharge will occur between 3 and 3. When slot discharge occurs, the ground insulation layer 2 of the stator coil will
The surface of the insulating layer is eroded, and the ground insulating layer 2 is eventually destroyed, resulting in serious damage.

[Problem to be solved by the invention]

As mentioned above, in a high-voltage rotating machine coil with full impregnation insulation, if the gap between the core slot and the coil is large, the coil will be placed in a deformed state within the core slot, and the core and external corona prevention layer will The contact area of the coil is reduced, and there is a risk of local heating of the external corona prevention layer and vibration of the coil due to electromagnetic vibration during operation, resulting in slot discharge. An object of the present invention is to provide a coil for a high-voltage rotating machine in which a gap between the core and an external corona prevention layer outside the coil is eliminated in the core slot, and the coil and core are brought into close contact with each other.

[Means to solve the problem]

The above purpose consists of a layer of unimpregnated mica tape wound multiple times on a wire conductor bundle, an outer corona prevention layer wound on the outside of this mica tape layer, and an end of this outer corona prevention layer. After forming an unimpregnated coil with an end corona prevention layer applied to the core and inserting the unimpregnated coil into the core slot and connecting, the unimpregnated coil and the iron core are integrated and placed in a vacuum chamber. In a high-pressure rotary machine coil that is vacuum-applied, impregnated with a thermosetting resin under pressure, and further cured, the external corona prevention layer is made of a crepe-like semiconductive material, and the crepe is applied to the outside of the mica tape-wrapped layer. A non-impregnated coil is formed by arranging a shaped semiconductive material, and after inserting the non-impregnated coil into the core thrower I and connecting it, the non-impregnated coil and the core are evacuated and heated in a vacuum chamber. This is achieved by impregnating a curable resin under pressure and further curing it.

[For use]

A crepe-shaped semiconductive material is placed on the outside of the mica winding layer, which is the ground insulation layer of the stator coil, to form an unimpregnated coil.
After inserting this unimpregnated coil into the iron core thrower I and connecting it, this unimpregnated coil and the iron core are evacuated in a vacuum layer, impregnated with thermosetting resin under pressure, and further hardened. To form a coil, when the unimpregnated coil is inserted into the core, the crepe-shaped semiconductive material deforms according to the gap between the ground insulating layer and the core, and comes into contact with the side wall surface of the core slot. After obtaining a good electrical connection between the mica tape layer, which is the ground insulating layer, and the iron core in this way, the gap in the deformed crepe-shaped semiconductive material itself is filled with thermosetting resin, and the ground insulating layer is The layers and core are electrically and structurally integrated by crepe-like semiconducting material and impregnated resin.

【Example】

The present invention will be described in detail below based on the drawings. FIG. 1 is a sectional view showing a state in which a high-voltage rotating machine coil according to an embodiment of the present invention is inserted into an iron core slot. 1st
In the figure, a mica tape is wound a necessary number of times depending on the voltage class on a reverse base material made of glass cloth, film, or non-woven fabric on a wire conductor bundle 1, and a mica tape winding layer 2
to form. A crepe-like semiconductive material 7 is placed thereon to serve as an external anti-corona layer. The crepe-shaped semiconductive material is made by attaching a semiconductive material made by kneading graphite powder to thermosetting resin such as epoxy resin to a heat-resistant film such as polyester film as a base material, and forming it into a crepe shape with arbitrary irregularities. This is what I did. The crepe-like semiconductive material may be either a prepreg type with a semiconductive material on one side and a semiconductive material on two sides, or a calender type, and the surface resistance after resin impregnation is about 5 to 500 Ω per cffl. Tapes and sheets with a thickness of about 0.3 to 2 nm, including unevenness, are used. Therefore, the arrangement of the crepe-shaped semiconductive material 7 is as shown in FIG. Insert the coil into the iron core. At this time, the crepe-shaped semiconductive material 7 is located near the bottom of the wedge 5 where there is almost no gap.
The core 4 is almost completely crushed, and the side surfaces of the iron core 4 are deformed to correspond to the gap. After that, by impregnating a thermosetting resin such as an epoxy resin, the resin is retained in the crepe-shaped gap, and the mica tape-wrapped layer 2, which becomes the main insulating layer, and the iron core 4 are coated with the crepe-shaped semiconductive material 7 and the impregnated resin. They are electrically and structurally integrated through the resin. Further, when the retention of the impregnated resin near the crepe-like semiconductive material 7 is further enhanced, the crepe-like semiconductive material 7 may be treated with an amine-based accelerator or the like. Furthermore, as a method of arranging the crepe-shaped semiconductive material 7 on the ground insulating layer, a conventionally used flat plate-shaped external corona prevention tape is wound on the ground insulating layer, and then a crepe-shaped semiconductive material 7 is placed on the ground insulating layer. There is a method of winding the conductive material 7. Figure 2 shows the applied voltage and dielectric loss tangent (t) of the high-voltage rotating machine coil.
an δ). Figure 2 shows a fully impregnated coil using a simulated core with a rated voltage class of 1 lkv (an iron core with a coil pitch and slot angle simulating the actual machine). The target coils were coils made of steel and coils as shown in Figure 4, in which the gap between the iron core and the coil was 0.8 mm on one side, as in the past. The initial characteristics of the two types of coils were almost the same, but after 3 months of applying vibration at an acceleration of 3G and a voltage 1.5 times the rated voltage at the same time, the characteristics were as shown in Figure 2. As can be seen from FIG. 2, compared to coil A according to the embodiment of the present invention, coil B according to the conventional example has tan
The value of δ is high at 2 kV, and the value of tan δ increases as the applied voltage increases. This is because coil A according to the present invention and coil B according to the conventional example were evaluated using the same main insulation, so it was suggested that the external corona prevention layer 3 of the conventional coil B was damaged. Damage was also confirmed. However, no particular abnormality was observed in the coil A according to the example of the present invention even when it was disassembled and observed. Although the above description has been made regarding a fully impregnated coil, a prepreg or calender type crepe-like semiconductive material can be used when inserting a resin-rich coil or a single impregnated coil into an iron core.

【Effect of the invention】

According to this invention, since the crepe-shaped semiconductive material is provided on the ground insulating layer, when an unimpregnated coil is inserted into the iron core, the crepe-shaped semiconductive material is attached to the ground insulating layer and the iron core. deforms according to the gap between and hits the side wall surface of the core slot. After obtaining a good electrical connection between the mica tape layer, which is the ground insulating layer, and the iron core in this way, the gap between the deformed crepe-shaped semiconducting material is filled with thermosetting resin, and the ground insulating layer is The layers and core are electrically and structurally integrated by crepe-like semiconducting material and impregnated resin. Therefore, it becomes easy to manage the gap between the external corona prevention layer and the iron core, and it is also easy to insert the coil into the core thrower I, improving work efficiency and reducing the cost of the rotating machine. Furthermore, since the coil and iron core are brought into close contact, damage such as electrical discharge can be prevented, making it possible to provide a rotating machine with high reliability.This coil is easy to maintain and can operate stably over a long period of time. can do.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a state in which a high-voltage rotating machine coil according to the present invention is inserted into an iron core, and FIG. 2 is a diagram showing the relationship between the applied voltage of the high-voltage rotating machine coil and 1ean δ.
Figure 3 is a cross-sectional view of a conventional high-voltage rotating machine coil;
The figure is a sectional view showing a state in which the high-voltage rotating machine coil of FIG. 3 is inserted into the iron core thrower I. 1: Cotton conductor bundle, 2: Mica tape wrapping layer as ground insulating layer, 3: External corona prevention layer, 4: Iron core 4.4a: Iron core slot, 5: Wedge, 6: Intarsia, 7: Crepe-shaped half conductive material. ('/,)9u too

Claims (1)

[Claims] 1) An unimpregnated mica tape layer wound multiple times on a wire conductor bundle, an external corona prevention layer wound on the outside of this mica tape layer, and a layer applied to the end of this external corona prevention layer. After forming an unimpregnated coil with an end corona prevention layer and inserting the unimpregnated coil into the core slot and connecting the wires, the unimpregnated coil and the iron core are integrated and evacuated in a vacuum chamber. and a high-voltage rotating machine coil in which a thermosetting resin is impregnated under pressure and further cured, wherein the external corona prevention layer is made of a crepe-like semiconductive material, and the crepe-like semiconducting layer is formed on the outside of the mica tape-wrapped layer. A conductive material is arranged to form an unimpregnated coil, and after this unimpregnated coil is inserted into the core slot and connected, the unimpregnated coil and the iron core are evacuated in a vacuum chamber and a thermosetting resin is applied. A high-pressure rotating machine coil characterized by being impregnated under pressure and further hardened.