JPS58130735A - Stator winding for rotary electric machine - Google Patents

Abstract

PURPOSE:To prevent occurrence of end corona by construction wherein an asbestos tape of a desired length is wound round a stator winding main insulating layer at the slot end in a manner that one end of the asbestos tape overlaps a low resistance tape covering the outer periphery of the stator winding main insulating layer. CONSTITUTION:A conductor 3 provided with a coatong which comprises a main insulating coating layer 2 formed of a wound mica tape or so and a low resistance tape 4 wound round the main insulating coating layer 2, is arranged in a slot of a core 1. An asbestos tape is wound round the main insulating coating layer 2 of the conductor 3 projected from the slot end in a manner that one end of the asbestos tape overlaps the low resistance tape 4, thereby to form an asbestos tape coating part 5. By so doing, since the asbestos tape will not lose its non-linearity of the resistance-voltage characteristic even with impregnation of resin, end corona can be prevented assuredly even in high-voltage rotary electric machines which will be subject to total impregnation processing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for preventing end corona in a stator winding of a rotating electrical machine.

In high-voltage rotating electric machines with a rated voltage of 6.6 kV or more, corona in the creeping direction, so-called end corona, occurs in the insulating layer at the end of the stator slot due to the presence of an electric field. child. The end corona generated in the Nosro 7 mfm damages and deteriorates the insulating layer along with the internal corona, and threatens the life of the equipment.
In the case of plastic carriers, it is necessary to prevent the occurrence of end corona by reducing the concentration of electric charge at the slot and toe ends.

In general, when manufacturing stator windings for two single-turn coils, the insulation method is as follows: 1) Complete the insulation layer of the winding and then insert it into the iron core.

11) The insulating layer is assembled into the unfinished iron core, and then completed as an insulating layer through insulation treatment (resin impregnation) (referred to as a fully impregnated insulating stem). It can be divided into

In the case of 1), since the insulating layer has been completed, it is relatively easy to perform end-corona prevention treatment on its surface by coating it with blood, etc., which is mainly composed of k8iC and has non-linear resistance-voltage characteristics. It's easy.

In the case of ii), since the insulating layer is unfinished, it is impossible to perform the former treatment. For this reason, in the past, for example, glass tape was impregnated with a compound to give it an appropriate resistance percentage, and this tape was made into J! It was wound around the edge layer to prevent the coil end from scratching.

However, this method cannot reliably prevent the occurrence of end corona. It is the resistance of the tape -
This is because the resistance to voltage changes greatly due to resin impregnation. FIG. 1 illustrates the resistance-voltage characteristics of this type of tape. Before being impregnated with resin, this tape exhibits a low but highly non-linear resistance to voltage, as shown by the solid line in the figure. -jl) The resistance value always becomes high, and the nonlinearity in the resistance-voltage characteristic is still impaired.

As a result, the concentration of electric field at the slot end IBK could not be alleviated. Other disadvantages of this tape include that it is quite expensive and difficult to handle.

An object of the present invention is to provide a stator winding for a rotating electric machine that solves the problems in conventional end corona prevention. This objective is achieved by wrapping the stator winding raw insulating layer at a location close to the stator slot ends with asbestos tape.

Hereinafter, an embodiment of the stator mold for a rotating electric machine according to the present invention will be described with reference to FIGS. 2 and 13.

FIG. 2 is an interlayer diagram showing the resistance-voltage characteristics of asbestos tape, and FIG. 3 is a schematic partial cross-sectional view of the end of a stator of a rotating electric machine. In FIG. 2, the solid line shows the original resistance-voltage characteristics of asbestos tape. Asbestos 1 has non-@ wire resistance-voltage characteristics.

FIG. 3 is a sectional view of the slot end of an iron core 1 using asbestos tape whose resistance-voltage characteristics are shown in FIG. 2.

A conductor 3 with a main insulating layer 2 made of mica tape or the like is led out from a coil (not shown), and a low-resistance tape 4 is attached to the conductor 5 to widen the gap between the main insulating layer 2 and the iron core 1.
is wound.

One end is overlapped with the part indicated by 8 on the terminal side of this chi 14, and the asbestos tape is overlapped half and wrapped once (9) on the main gun I# covering layer 2 to form an asbestos tape covering ss5. The non-linear resistance-voltage characteristic of s5 shown by the solid line in FIG. 2 prevents the occurrence of end corona.

In this case, as the asbestos tape, a commercially available asbestos tape having a thickness of 0.5 to 1.0 m can be used as is. On the other hand, as a low-resistance tape, for example, a polyester film coated with carbon paint and having a surface resistance value of several hundred to several thousand 0/mouth is used. In high-voltage electric machines with a rated voltage of 11 kV, asbestos steel 1 is rolled half overlapping, and one turn is 1-50m.
It is wound with a length of m.

This asbestos tape-covered part 5 exhibits the non-linearity shown by the solid line in Figure 2 when it has only been applied *a as described above, and even after being impregnated with resin according to the full impregnation insulation system of the & One point fi! As shown by al, non-linearity almost coincides with the solid line before resin impregnation. That is, asbestos tape maintains its inherent non-linear resistance-voltage characteristics almost unchanged even after resin impregnation and curing.

According to the present invention, as mentioned above, if an asbestos tape whose resistance-1 pressure characteristic is non-linear is used, from K,
41Hm, can prevent the occurrence of end roller □ without any treatment, especially ・Fully impregnated treatment gI! In insulation systems for high-voltage rotating electric machines, resin impregnation has a remarkable effect of preventing non-linearity and preventing corona. Moreover, Asbestos-1 can be made 1/20th cheaper than the conventional method of impregnating glass tape with paint.

And taping work is also easy. Furthermore, one rotating electric machine has 100 to 20 end corona prevention points.
Even considering the fact that there is a 0m distance, it is possible to reduce the manufacturing man-hours and price of a large-sized vessel. In addition, asbestos tape, which has excellent heat resistance, maintains stable characteristics over time as an end corona prevention agent, and can be useful for improving the reliability of rotating electric machines.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the resistance-voltage characteristics of a conventional end corona prevention tape, Fig. 2 is a diagram showing the resistance-voltage characteristics of asbestos tea 1 used in the endocorona prevention method according to the present invention, and Fig. 3 The figure is a schematic partial cross-sectional view of the stator end of the rotating electric machine, which is an embodiment of the end corona prevention method according to the present invention. DESCRIPTION OF SYMBOLS 1... Iron core, 2... Main insulation covering layer, 3... Body,
4...Low resistance tape covered part, 5...Asbestos tape covered part 4 lying down.

Claims (1)

[Claims] 1) Fixed pre-winding of rotating electric machine! In 11, the stator slot;
A low-resistance tape is wound around the main insulation coating layer of the stator winding at the end of the stator winding, and one end of the asbestos tape is overlapped with the outer end of the low-resistance wire. Stator seaming for rotating electric machines involves winding the wire around the main insulation coating layer to cover the required length. 2. In the item 1 described in claim 11, the thickness is 0.
．． A stator winding of a rotating electric machine with 4111 asbestos tape of 6 m to 10 liters wrapped around the main insulating coating layer.