JPH0795739A - Structure for preventing spark discharge of stator winding caused by vibration - Google Patents

Abstract

PURPOSE:To prevent spark discharge of a stator winding caused by vibration by bringing outer corona preventing layers surrounding the main insulating layer to the earth of stator coils in a slot into direct contact with one wall of the slot in a conductive state and indirect contact with the other wall of the slot through semiconductor side liners and filling the void of the slot with a semiconductive rubber filler. CONSTITUTION:Two stator coils 3B and 3A are inserted into a slot 2 by using a wedge 8 and liners 7C-7A. Outer corona preventing layers 6 are put around the coils 3A and 3B with main insulating layers 5 to the earth in between. The layers 6 are brought into direct contact with one wall of the slot 2 in a conductive state and the other wall of the slot 2 through semiconductive side liners 9B and 9A. Voice formed among cores, the layers 6, and the liners 9B and 9A in the slot 2 are eliminated by filling the voids with a conduction rubber filler. Therefore, the occurrence of spark discharge caused by vibration can be prevented and the coils can be used for a long period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows conductive contact between an outer corona preventive layer on the surface of a stator coil and an iron core by vibrating a stator winding of a high voltage and large capacity generator, an electric motor or the like during operation. The present invention relates to a vibration spark discharge prevention structure provided in a stator core in order to prevent a phenomenon (vibration spark discharge or vibration spark) that changes intermittently and a spark discharge occurs due to a potential difference between the two.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view showing a conventional support structure for a stator winding in a slot. A slot 2 formed in a stator core 1 has a pair of a lower coil 3A and an upper coil 3B. The stator coil 3 is housed. The stator coil 3 is formed by covering the periphery of the molded coil conductor 4 with the main insulating layer 5 to the ground, and vacuum-impregnating and heating the epoxy resin or the like to the mycatape or the laminated mycatape taped to a predetermined thickness. An external corona-preventing layer 6 made of, for example, a coating film of a semiconductive paint is formed on the surface of the cured main ground insulating layer 5. A slot bottom liner 7A and an interphase liner are provided above and below the pair of stator coils 3A and 3B and between the phases.
7B and the lower wedge liner are interposed, and in the gap between the stator coil 3 and one side wall surface of the slot 2, semi-conductive side liners 9A and 9B which are vertically divided into two are interposed. The stator coil 3 is fixed in the slot 2 by driving the wedge 8 and covering the opening of the slot 2.

By the way, a semiconductive side liner-9A,
9B has graphite fleece and graphite paper
A flat plate liner made of, for example, is used, and by being pushed into the gap between the coil and the iron core, one surface of the outer corona prevention layer 6 is in direct conductive contact with the side wall surface of the slot, and the other surface opposite to this. Conductively contacts the side wall surface of the slot 2 through the semiconductive side liner-9. It is also known that the semi-conductive side liner is not divided into 9A and 9B, but the semi-conductive side liner is integrated into the coil and the iron core as a vertically integrated semi-conductive side liner.

[0004]

The outer corona preventive layer 6 of the stator coil 3 has a stator core 1 whose surface is grounded.
By causing a charging current flowing through the electrostatic capacitance of the ground main insulating layer 5 in a conductive contact with the ground side through the iron core,
The voltage generated in the gap between the outer corona preventive layer 6 and the stator core 1 is reduced to prevent spark discharge (called outer corona) in this gap. The stator core 1 made of a laminated body of iron core plates is insulated from each other in order to reduce the eddy current loss, and a voltage is generated between the iron core plates due to the electromagnetic induction action.
The outer corona prevention layer is brought into conductive contact with the side wall surface of the slot,
The iron core plate is configured to also function as a conductive path for resistance grounding via the external corona preventive layer.

However, in recent years, a vibration spa
Attention has been paid to the phenomenon of stator coil discharge deterioration due to vibration (vibrating spark discharge). That is, the ground main insulating layer 5 of the stator coil 3 which is at a high temperature during operation contains a large amount of organic substances such as epoxy resin, and the epoxy resin is thermally deteriorated during long-term operation, so that the ground main insulating layer is gradually deteriorated. The contraction is accelerated due to the vibration of the stator coil 3 that occurs during operation. However, the conventional semi-conductive side liner 9 composed of graphite fleece, graphite paper, etc. compensates for the contraction of the main insulating layer to fill the gap, and the conductive contact state between the outer corona preventive layer and the iron core. The conductive contact surfaces 10A, 1A, which had a good conductive contact state at the beginning of manufacture, because they do not have elasticity enough to hold
Since a minute gap is generated in 0B and 10C and the minute gap is contracted or opened due to the vibration of the stator coil, a switching phenomenon occurs that makes the conductive contact state unstable. The function of the outer corona-preventing layer as a conductive path for approaching the temperature decreases, and a spark discharge occurs along with the switching phenomenon. This phenomenon is called vibration spark (vibration spark discharge), the external corona prevention layer 6 is damaged by the spark discharge, and the vibration spark discharge is intensified, and the ground main insulating layer 5 is discharged by the intensified spark discharge. Preventing vibration spark discharge has become an important issue because it causes deterioration and progresses to a ground fault in the stator winding.

An object of the present invention is to prevent vibration spark discharge that can prevent the spark from occurring by maintaining the conductive contact state between the outer corona preventive layer and the iron core even if the switching phenomenon occurs due to the vibration of the stator coil. To get the structure.

[0007]

In order to solve the above-mentioned problems, according to the present invention, two upper and lower stator coils wound in slots formed in a stator core made of a laminated body of core blocks. Is provided with a semi-conductive outer corona-preventing layer on the surface of the main ground insulating layer, and one surface of the outer corona-preventing layer is in direct conductive contact with the side wall surface of the slot and the other surface opposite to the semi-conducting anti-corona preventing layer In the one fixed in the slot so as to be in conductive contact with the side wall surface of the slot via the conductive side liner, the gap between the slots is filled to keep the conductivity between the outer corona preventive layer and the stator core. And a semiconductive rubber filler layer.

The semi-conductive rubber filler layer is made of a semi-conductive silicone compound material which is filled into the voids in the slots including the gaps at the corners of the stator coil having a rounded shape by dividing the core blocks. And A stator coil composed of a laminated body of iron core blocks is provided with two upper and lower stator coils wound in slots formed in a core, and a semiconductive outer corona preventive layer is provided on the surface of the ground main insulating layer. One surface of the corona prevention layer is in direct conductive contact with the side wall surface of the slot, and the other surface opposite thereto is a semiconductive side liner.
Fixed in the slot so as to be in conductive contact with the side wall surface of the slot via the semi-conductive side liner, the semi-conductive irregularities formed by the protrusions formed by extrusion from the surface opposite to the semi-conductive side liner. It shall consist of a side liner.

It is assumed that the convex portions are distributed and formed so as to be alternately adjacent to both surfaces of the semiconductive concave-convex side liner.

[0010]

In the present invention, the vibration spark discharge prevention structure is
By using a semi-conductive rubber filler layer that fills the voids in the slots and maintains the conductivity between the external corona preventive layer and the stator core, a semi-conductive rubber filler layer rich in elasticity is obtained. Since the core and the outer corona preventive layer, the outer corona preventive layer and the semi-conductive side liner, and the semi-conductive side liner and the iron core are respectively coupled to maintain the conductive contact state without peeling due to the switching phenomenon, the outer corona The prevention layer and the iron core can be kept near the ground potential to prevent the generation of sparks, and the function of preventing damage to the stator coil due to vibration spark discharge (vibration spark) can be obtained.

Further, a semi-conductive rubber compound material is filled with a semi-conductive rubber filler layer divided into core blocks in a space within a slot including a gap between corner portions of a rounded stator coil. If so, the semiconductive silicone compound material is rubberized to obtain a function of preventing vibration spark discharge, and the silicone compound material having excellent heat resistance exhibits heat resistance and the rubber thereof is used. Since the elasticity is maintained for a long time, it is possible to obtain a vibration spark discharge prevention structure having excellent long-term stability.

Further, if a semi-conductive side liner is formed by extruding and molding the semi-conductive side liner from the opposite surface side to form a semi-conductive uneven side liner, the pressing force is applied to the convex part. By inserting it into the gap between the stator coil and the inner wall surface of the slot, the convex portion retains elasticity and compensates for dimensional contraction due to thermal deterioration of the main insulating layer, and switching accompanying vibration of the stator coil The function of preventing the phenomenon and stabilizing the contact resistance on the conductive contact surface can be obtained. Further, if the convex portions are formed so as to be alternately adjacent to both surfaces of the semi-conductive irregular side liner, the elasticity of the liner is increased by utilizing the bending elasticity of the flat plate portion between the convex portions. A function of stably compensating for dimensional shrinkage due to thermal deterioration of the insulating layer can be obtained.

[0013]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a sectional view showing a vibration spark discharge preventing structure for a stator winding according to an embodiment of the present invention, and FIG. 2 is a perspective sectional view showing a main part of the embodiment. Duplicated description will be omitted by giving reference numerals.
In the figure, 11A, 11B, ... 11F and the like 11 are semi-conductive rubber filler layers that are filled in the voids in the slots 2 and maintain the conductivity between the outer corona preventing layer 6 and the stator core 1. Yes, the semiconductive rubber filler layer 11 is made of a semiconductive silicone compound material, and the corner portions of the stator coils 3A, 3B, etc., which have roundness when the stator coils 3A, 3B are inserted into the slots 2 As shown in FIG. 2, the core blocks 1A, 1
Each B is divided and filled sequentially from the bottom of the slot.

The semiconductive silicone compound material filled in the gaps in the slots undergoes a reaction with the passage of time to exhibit rubber elasticity and vibrates with a semiconductive rubber filler layer 11 having a high elasticity. A spark discharge prevention structure is formed and conductively coupled to the iron core and the outer corona prevention layer, the outer corona prevention layer and the semi-conductive side liner, and the semi-conductive side liner and the iron core respectively, and the iron core plate is connected to the outer corona prevention layer 6 Resistive coupling to each other through the use of the silicone rubber, the excellent heat resistance of the silicone rubber is utilized to maintain a stable conductive contact state for a long period of time without peeling due to switching phenomena. Vibration spark discharge that prevents sparks by forming a stable conductive path between the iron core and the external corona prevention layer even if a switching phenomenon occurs such as opening or closing a large gap Baibure - Shonsupa - h) preventing effect is obtained, the advantage of preventing damage to the stator coil due to vibration spark discharge is obtained.

FIG. 3 is a cross-sectional view showing a structure for preventing vibration spark discharge of a stator winding according to a different embodiment of the present invention, and FIG. 2 is a perspective cross-sectional view schematically showing a semiconductive uneven sideliner in a different embodiment. It is a figure. In the figure, the structure for preventing the stator spark 3 from vibrating spark discharge is shown in FIG.
It is configured as a semi-conductive uneven sideliner -21 interposed between the side wall surface and the side wall surface. Semi-conductive uneven side liner
Reference numeral 21 denotes a heat press having, for example, graphite fleece containing a resin binder, graphite paper, etc., and having, for example, a truncated spherical crown-shaped female mold and a male mold on portions of the pressing mold surface facing each other. It is formed as a molding material in which the convex portions 22A and 22B are alternately distributed on both surfaces. The semiconductive uneven sideliner-21 thus obtained has the concave portion 23A on the back side of the convex portion 22A,
A concave portion 23B is formed on the back side of the convex portion 22B, and the curved convex portion 22 having substantially the same thickness of the material has spring elasticity, so that the convex portion 22B and the stator coil 3 and the slot are pressed so that a pressing force is applied to the convex portion. By pushing together with the stator coil into the gap between the side wall surface of 2 and the convex portion, elasticity is retained and the dimensional contraction due to thermal deterioration of the main insulating layer is absorbed, and the conductivity between the outer corona preventing layer 6 and the iron core 1 is reduced. Since the contact state is stably maintained, the switching phenomenon accompanying the vibration of the stator coil is absorbed, the contact resistance on the conductive contact surface is stabilized, and the generation of vibration spark discharge can be prevented.

The semi-conductive uneven side liner may be so constructed that its convex portion is formed only on, for example, the surface on the side of the outer corona preventing layer, and the side wall surface of the slot is flattened so as to be in full contact with each core plate. Good. In addition, the vibration spark discharge prevention structure may be configured to have a composite structure of the semiconductive rubber filler layer 11 and the semiconductive uneven sideliner -21. With such a structure, higher vibration spark discharge Preventive effect is obtained.

[0017]

As described above, the present invention provides an oscillating spark discharge comprising a semiconductive rubber filler layer filled in the voids in the slots to maintain the conductivity between the outer corona preventive layer and the stator core. One or both of the prevention structure and the vibration spark discharge prevention structure including a semi-conductive irregular side liner inserted in a gap between the stator coil and the side wall surface of the slot so that a pressing force is applied to the convex portion. As a result, the semi-conductive rubber filler layer, which is highly stretchable, maintains a conductive contact state without peeling due to the switching phenomenon, and the convex portions of the semi-conductive irregular side liner maintain elasticity to provide main insulation. The dimensional contraction due to the thermal deterioration of the layer is compensated for, and the instability of the conductive contact state accompanying the switching phenomenon is eliminated, so that the vibration spark discharge (vibration spark), which has been a problem in the prior art, can be prevented. Therefore, it is possible to provide a highly reliable high-pressure and large-capacity rotating machine having a vibration spark discharge prevention structure capable of stably preventing damage to the stator coil due to vibration spark discharge for a long period of time. Further, by adding the vibrating spark discharge prevention structure of the present invention, it is possible to prevent the trouble caused by the vibrating spark discharge, which has been a problem in the prior art, so that there is an advantage that the loss cost accompanying the trouble can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a vibration spark discharge prevention structure for a stator winding according to an embodiment of the present invention.

FIG. 2 is a perspective sectional view showing a main part of the embodiment.

FIG. 3 is a sectional view showing a vibration spark discharge prevention structure for a stator winding according to another embodiment of the present invention.

FIG. 4 is a perspective sectional view schematically showing a semiconductive uneven sideliner in a different embodiment.

FIG. 5 is a cross-sectional view showing a conventional support structure for a stator winding in a slot.

[Explanation of symbols]

1 Stator Iron Core 1A Iron Core Block 2 Slot 3 Stator Coil 4 Coil Conductor 5 Ground Insulation Layer 6 External Corona Prevention Layer 7 Liner 9 Semi-conductive Side Liner (9A, 9B) 10 Conductive Contact Surface 11 Semi-conductive Rubber Filler layer (11A, 11B ...
11F) 21 semi-conductive irregularity side liner-22 convex part 22A convex part 22B convex part 23 concave part 23A concave part 23B concave part

Claims (4)

[Claims] 1. A stator coil having two upper and lower windings wound in a slot formed in a stator core made of a laminated body of iron core blocks, wherein a semiconductive outer corona preventive layer is provided on the surface of the main insulating layer to ground. The outer corona-preventing layer has one surface directly in conductive contact with the side wall surface of the slot, and the other surface opposite thereto has conductive contact with the side wall surface of the slot through the semi-conductive side liner. In the one fixed in the inside, there is provided a semi-conductive rubber filler layer filled in the void in the slot and holding conductivity between the outer corona preventing layer and the stator core. Vibration spark discharge prevention structure for the child winding. 2. A semi-conductive silicone compound material filled into a void in a slot including a gap in a corner of a stator coil having a semi-conductive rubber filler layer having a roundness by dividing each core block. The vibration spark discharge preventing structure for a stator winding according to claim 1, wherein: 3. A stator coil having two upper and lower windings wound in a slot formed in a stator core made of a laminated body of iron core blocks, wherein a semiconductive outer corona preventive layer is provided on the surface of the ground main insulating layer. The outer corona-preventing layer has one surface directly in conductive contact with the side wall surface of the slot, and the other surface opposite thereto has conductive contact with the side wall surface of the slot through the semi-conductive side liner. The stator winding is characterized in that, in the one fixed inside, the semi-conductive side liner comprises a semi-conductive uneven side liner formed by distributing convex portions extruded from the opposite surface side. Wire vibration spark discharge prevention structure. 4. The vibration spark discharge preventing structure for a stator winding according to claim 3, wherein the convex portions are formed so as to be alternately adjacent to each other on both sides of the semiconductive concave-convex side liner. .