JPS59226633A - Stator coil of rotary electric machine - Google Patents

Abstract

PURPOSE:To eliminate a void in a high strength insulating layer which covers the boundary between a semiconductive layer and the insulating layer and the semiconductive layer by providing the insulating layer on the conductor side boundary of a main insulating layer which is contacted with the semiconductive layer formed in the main insulating layer and a low resistance corona shielding layer as well as an electric field alleviating side boundary. CONSTITUTION:Separable mica tape is wound on the outer periphery of a conductor 2 of a stator coil 1 to form a main insulating layer 3, and a lumped mica tape is wound from the position of approx. 20mm. of a stator core side from a stator core side end of a semiconductive layer 4 to the position of approx. 50mm. of the coil end side from the coil end side of an electric field alleviating layer 6 on the outer periphery of the layer 3 to form a high strength insulating layer 7. Then, a semiconductive tape is wound on the outer periphery of the layer 7 to form the semmiconductive layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stator coil for a rotating electric machine, and more particularly to a stator coil having a structure that improves prevention of partial discharge or creeping discharge at the terminal portion of the stator coil.

BACKGROUND ART As rotating electric machines have recently become higher in voltage, larger in capacity, and smaller and lighter in size, electric field mitigation at stator coil terminals has become an important issue. Therefore, in order to prevent creeping discharge, it has been common practice to provide an electric field relaxation layer in contact with a low-resistance corona shield layer. As the electric field relaxation layer for this AC voltage, paints having nonlinear resistance characteristics or low resistance linear resistance paints are generally used. but,
As the rated voltage increases, the AC test voltage also increases, raising the risk of creeping discharge and burnout of the corona shield layer. In order to compensate for the above-mentioned drawbacks, an invention has been filed for a rotating electric machine stator coil characterized in that a semiconducting layer is provided inside the main insulating layer (Japanese Patent Application No. 1999-1991, Tough-08'l Co., Ltd.).

FIG.
/) The structure is shown in which the main insulating layer 3 is formed by winding mica tape to a predetermined thickness around the outer periphery of the conductor of the stator coil L, and then the semiconducting layer 3 is formed around the outer periphery of the main insulating layer 3. will be established. Furthermore, a mica tape is wound around the outer periphery to form a main insulating layer J, which is then impregnated with a synthetic resin and polymerized and press-molded. After this is a low resistance corona shield layer! , and an electric field relaxation layer 6 are provided to constitute the stator coil l. The characteristics of this insulation structure are to reduce the power loss near the joint of the electric field relaxation layer B, and further to disperse the locations where power loss occurs in the electric field relaxation layer B, thereby suppressing the temperature rise of the electric field relaxation layer B near the seam. The purpose is to make it difficult to cause thermal destruction.

A stator coil having the above-mentioned characteristics exhibits its effects most when used in a high-voltage, large-capacity generator.

The conventional main insulation structure for high voltage, large capacity generators is to wrap removable mica tape, which has excellent corona resistance and mechanical strength, and further impregnate it with epoxy resin, which has excellent electrical and mechanical properties. Commonly used. (For example, Ko Kadotani, Hitachi Hyoron Vol.

61, A6! , / ? qter S, y) Peelable Mica has particularly excellent toughness when a very large stress is applied to the insulating layer, and has been widely used in large-capacity generators with long coils. In terms of electrical strength, peelable mica insulation has a very high breakdown voltage in the direction that penetrates the insulation layer (through-layer direction), but on the other hand, the breakdown voltage in the along-layer direction along the peelable mica piece is relatively low. low. Therefore, when a semiconducting layer is provided within this peel-off mica insulating layer, the breakdown voltage in the longitudinal direction is low, so the breakdown path develops in the longitudinal direction, and the initial effect of providing the semiconducting layer is not fully realized. There was a drawback that it was not achieved.

The present invention has been made in view of the above-mentioned drawbacks, and aims to provide a stator coil for a rotating electrical machine free from the above-mentioned drawbacks. By providing a high-strength insulating layer with excellent electrical and mechanical strength in both the penetration and longitudinal directions at the conductor-side interface of the main insulating layer and the low-resistance corona shield layer and electric field relaxation layer-side interface, (3) the above-mentioned conventional It is an attempt to remove the defects of something.

The invention will now be described with reference to illustrative embodiments.

FIG. 2 is a diagram showing a basic embodiment of the present invention, in which a peelable mica tape is wound around the outer periphery of the conductor of the stator coil L to a predetermined thickness to form the main insulating layer 3, and then the main insulation layer 3 is formed. From the outer periphery K of the insulating layer 3, from a position about -〇- on the stator core side from the stator core side terminal of the semiconducting layer DA, to the coil terminal side,
Approximately jO from the coil terminal side end of the electric field relaxation layer B to the coil terminal side
For example, laminated mica tape 1~
It is wound three times to form a high-strength insulating layer 7. Thereafter, a semiconductive tape is wound around a predetermined position on the outer periphery of the high-strength insulating layer to provide a semiconductive layer. Furthermore, 1 to 3 pieces of laminated mica tape are applied to the outer periphery in the same area as the high-strength insulating layer 7.
After winding to form a high-strength insulating layer, a peelable mica tape is wound to a predetermined thickness to form the main insulating layer 3. Thereafter, it was impregnated with a synthetic resin, polymerized, and press-molded (4'). Thereafter, a low resistance corona shield layer S and an electric field relaxation layer 6 are provided at predetermined positions to constitute a stator coil I.

In the stator coil constructed as described above, a high-strength insulating layer 7 is provided to cover the semiconducting layer.

The laminated mica tape shown as the constituent material of the high-strength insulating layer 7 in the examples is made by crushing the mica raw edge into minute scales and making paper, so the fit when the laminated mica tape is wound is Therefore, when impregnated and polymerized with a synthetic resin, the adhesion to the semiconductive layer is very good. Furthermore, the composite mica insulating structure provided by impregnating and polymerizing a composite mica tape layer with a synthetic resin has a feature of high button breakdown voltage in both the through-layer direction and along-layer direction. Therefore, in the stator coil l in which a high-strength insulating layer is provided to cover a semi-conducting layer using a composite mica insulating structure, the interface between the semi-conducting layer and the high-strength insulating layer 7 and the semi-conducting layer are The generation of voids in the covering high-strength insulating layer 7 can be suppressed. Therefore,
When a high voltage is applied, it is possible to suppress the occurrence of partial discharges from the semiconducting layer and the occurrence of partial discharges in voids around the semiconducting layer, and to increase the dielectric breakdown voltage in the layer direction. effective.

The present invention is characterized by improving the adhesiveness of the interface between the insulating layer and the semiconducting layer provided for the purpose of preventing partial discharge or creeping discharge at the end of the stator coil. The purpose is to suppress the occurrence of partial discharge inside the insulating layer by eliminating voids in the insulating layer near the conductive layer 1, and to improve the breakdown voltage in the longitudinal direction of the insulating layer near the semiconducting layer q.

Therefore, the range in which the high-strength insulating layer is provided is from the stator core side terminal of the semiconducting layer DA to the position of approximately θ θ on the stator core side, to the coil terminal side end of the piezoelectric field relaxation layer B on the coil terminal side. However, considering the potential distribution when a high voltage is applied, the range in which the high-strength insulating layer 7 is provided is approximately 500 mm on the coil terminal side. C from the position of the joint between the electric field relaxation layer and the base of the electric field relaxation layer.
ri) It suffices if it is on the stator core side, and if the coil terminal side is closer to the coil terminal side than the coil terminal side end of the electric field relaxation layer base,
Of course, the range is not particularly limited. Furthermore, the constituent material of the high-strength insulating layer 7 is not limited to the laminated mica tape, but may also be a material that has good adhesion to the semiconducting layer and the main insulating layer 3 and has a high breakdown voltage in the longitudinal direction. For example, mica tape, synthetic resin film, etc., which are different in type and properties from the main insulating layer 3, can have the same effect.

Furthermore, the thickness of the high-strength insulating layer 7 does not limit the number of turns of the material constituting the high-strength insulating layer 7 to 7 to 3, and the thickness of the high-strength insulating layer 7 depends on the voltage applied to the stator coil and the It may be determined as appropriate depending on the manufacturing process, etc.

As described above, the stator coil for a rotating electric machine according to the present invention has a conductor-side interface of a semiconducting layer provided within an insulating layer,
A high-strength insulating layer is provided at the interface on the side of the low-resistance corona shield layer and the electric field relaxation layer, and the semi-conducting layer is covered with high-strength insulating layer pressure (t), thereby forming a high-strength insulating layer between the semi-conducting layer and the high-strength insulating layer. The generation of voids in the high-strength insulating layer covering the layer interface and the semiconducting layer can be eliminated. This has the effect of suppressing the occurrence of partial discharges from the semiconducting layer and the occurrence of partial discharges in voids in the insulating layer around the semiconducting layer when a high voltage is applied. It also has the effect of increasing the breakdown voltage in the longitudinal direction of the insulating layer around the semiconducting layer, thereby maximizing the effect of providing the semiconducting layer within the insulating layer (Japanese Patent Application No. 57-026<121). There is an effect that it can be done.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing a conventional stator coil, and FIG. 2 is a partial sectional view showing an embodiment of the stator coil according to the present invention. l...Stator coil, Co...Conductor 1. ?・・Main insulation layer,
DA: Semi-conducting layer, 5: Low resistance corona shield layer, 6:
- Electric field relaxation layer, 7... High strength insulating layer. Note that the same symbols in the figures indicate the same or corresponding parts. Agent Masuo Oiwa (6) ■

Claims (1)

[Claims] A conductor, a main insulating layer covering the conductor, a low-resistance corona shield layer coated on the surface of the main insulating layer, and a terminal portion of the main insulating layer around the outer periphery of the coil end. the main insulating layer between the conductor and a contact portion with an electric field relaxation layer having nonlinear resistance characteristics provided on the outer periphery of the main insulating layer in contact with an end of the low-resistance corona shield layer; and a semiconducting layer provided inside the main insulating layer both inside the main insulating layer between the electric field relaxation layer and the conductor. A high-strength insulating layer is provided on the main insulating layer on the conductor side in contact with the semiconducting layer, the low resistance shield layer, and the main insulating layer on the electric field relaxation layer side in contact with the low resistance corona shield layer. A stator coil for a rotating electric machine, characterized in that the semiconducting layer is covered with the high-strength insulating layer.