JPS59149764A - Manufacture of insulating coil for rotary electric machine - Google Patents

Abstract

PURPOSE:To improve the corona shielding action by integrating a ground insulating layer and a high resistance corona shielding layer, and varying the winding length of the ion containing asbestos layer to linearly approach to the surface potential distribution. CONSTITUTION:When hardening a prepreg insulating layer 4, varnish is suitably impregnated from the layer 4 to an asbestos containing layer 6a of the innermost layer. The ground insulating layer cured in the layer 4 and a high resistance corona shielding layer 5 are integrated. The surface potential distribution is slowly raised to approach to the linear state by altering the winding length of the iron containing asbestos layers 6a-6c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing an insulated wire ring for a rotating electric machine with good corona prevention.

[Technical background of the invention and its problems]

In recent years, there has been a trend towards ultra-large capacity water turbine generators and turbine generators, with water turbine generators having a capacity of over 250 MVA and turbine generators exceeding 500 MVA. It's starting to happen.

Generally, according to standards such as JET and A8M, the withstand voltage test value of the stator winding of a rotating electrical machine is [rated voltage x 2 + 3000 V]
) or [rated voltage x 2 + 1000 V]. However, for quality control purposes, the withstand voltage test of a single insulated wire ring for stator winding is usually performed at [rated voltage x 3] in order to take into account defects in work when storing the insulated wire ring in the slot of the iron core. It is being implemented. The biggest challenge in these withstand voltage tests is to ensure that the high-resistance corona shield layer to suppress creeping corona on the outer wire ring end from the iron core end or the tin foil end wrapped around the insulated wire ring to simulate the iron core is completely removed. The purpose is to confirm whether or not. Conversely, it is necessary to manufacture an insulated wire ring that can suppress creeping corona at the ends of the wire wire.

Conventionally, in rotating electric machines with a rated voltage of 20 kV or less, the structure of the absolute R wire ring is as shown in Figure 1. Stator core (1)
The stator insulated wire ring (2) is housed in the thrower (Ia), and this insulated wire ring (2) has an insulating layer (4) on the wire conductor (3).
), and the part that goes inside the thrower) (la) and the iron core (
1) A low-resistance corona shield layer (5) for preventing slot corona is provided on the portion of the cloth that slightly protrudes from the end, and a high-resistance corona shield layer (6) for preventing end corona is connected in front of it.
) will be established. In Figure 1 these shield layers (5).

(6) The reason for adding diagonal lines or dots is to clearly distinguish it from others, and it is not a cross-sectional representation.

When the high-resistance corona shield layer (6) is constructed by winding iron-containing asbestos tape, the winding length is approximately 350 mm.
It's a bear. However, this insulated wire ring has a rated voltage of 20
kV, so we would like to apply 60 kV as a single unit voltage test, but creeping corona may occur if it approaches 50 kV. Therefore, when this insulated wire ring is used in a turbine generator, the ends of the wire ring are fixed firmly and intricately in order to suppress electromagnetic vibration of the wire ring. Therefore, when a withstand voltage test is performed at a predetermined voltage, visible creeping corona occurs between adjacent wire wheels and fixed locations, and if this visible creeping corona occurs in large numbers, it may not be possible to conduct a withstand voltage test according to the standard.

Therefore, for forming a high-resistance corona shield layer of a high-voltage stator insulated coil with a rated voltage of 20 kV or more, it was considered to wind a tape coated with a silicone carbide paint having voltage nonlinear resistance characteristics. However, the winding length of this tape is required to be approximately 250 vm, and the winding length of this tape is approximately 250 vm.
Exceeding c) is K. In this case, even if you use a flexible silicone carbide paint to apply to the tape, the tape will become too hard and the curved part (2
c).

Therefore, if a high voltage Kl of around 60 kV is applied, a creeping visible corona may occur from the portion that does not fit.

The disadvantage of silicone carbide coated tape is that once creeping corona occurs, its restoring power is much worse than that of ferrous asbestos, and partial repair is not possible. It is something that we must try again. Moreover, if creeping corona occurs during a pressure test after the insulated wire ring (2) is housed in the thrower (la) of the iron core (1) and the wire end is fixed with a fixing member, repair work will be extremely difficult. becomes.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a rotating electric machine insulated coil having a good corona shield layer even when the rated voltage is 18 kV or higher.

[Summary of the invention] ゛In the present invention, a prepreg insulating tape is wound around a wire conductor having a straight portion and a bent portion that transitions from the straight portion to the curved portion outside the iron core to provide a prepreg-like insulation layer. From a predetermined distance away from the straight line of the iron core, the asbestos tape is wound over the prepreg insulating layer, past the bend, and with an anisotropic length beyond the bend. At this time, each ferrous asbestos layer is provided with a counter-insulating layer in the part near the iron core, and a low-resistance paint layer coated with a low-resistance paint other than ferrous asbestos between each layer. A face coating layer is formed by applying the same face as used for the prepreg insulating tape to the outside of each ferrous asbestos layer above the layer at a distance of 20 to 80 m from the low-resistance paint layer, and this wire is vacuum-applied. The prepreg insulating layer is cured by pressure heating, and the face of the prepreg insulating layer is infiltrated into each of the ferrous asbestos layers to form a high-resistance corona shield layer, and then a low-resistance paint layer is applied from the straight part into the core. By providing a low-resistance corona shield layer that is lower than the high-resistance corona shield layer to the vicinity of the outer middle part of the provided position, when the prepreg insulating layer is cured, the innermost iron-containing asbestos layer is moderately coated from the prepreg insulating layer. At the same time, the prepreg insulating layer is hardened and the ground insulating layer and the high-resistance corona shield layer are integrated into one piece with no minute gaps, and each ferrous asbestos layer is wound at different lengths. This gradually increases the surface potential distribution to make it closer to a straight line, thereby improving the corona shielding effect.

[Embodiments of the invention]

Example 1 A first example of the present invention will be described below with reference to FIG.

First, 30 to 45 parts by weight of Epicor 1004 (trade name, manufactured by Shell) as an epoxy resin, 5 to 10 parts by weight of diaminodiphenylsulfone as a curing agent, and 40 to 30 parts by weight of toluene were mixed and heated. An epoxy-based copolymerized phenol is produced by copolymerizing. 25 parts by weight of methyl ethyl ketone is added to this copolymerized pheno to obtain an epoxy pheno. Next, 20 inches or more of the epoxy face is applied to the mica sheet, heated and dried to produce a prepreg mica sheet, and this is cut into tapes.

The epoxy phenol is applied to the wire conductor (3) and the interlayer portion of the prepreg mica tape, and from the front, the prepreg mica tape is wound around the wire conductor (3) a predetermined number of times to form a prepreg-like insulating layer ( 4) Form. Next, 20W from within the assumed iron core end line! A Apply the same low-resistance paint as the low-resistance paint for slot corona prevention layer formation from a distant position.
A first low-resistance paint layer (7a) is formed by applying it to the bottom of the fin. Next, wind the iron-containing asbestos tape from a position 201111 away from the assumed iron core end line (A), that is, from above the first low-resistance paint layer (7a), to a position beyond the bent part (2c) of the wire ring (2). A first iron-containing asbestos layer (6a) is formed. Estimated core end line (4) of the straight part (2a) of this wire ring
Since the length from the bending part (2c) to the bending part (2c) is about 10 on, the length of the first iron-containing asbestos layer (6a) is about 90111111111111.

Next, from a position 20 m from the assumed iron core end line (A),
The low resistance paint 30 is applied on the iron-containing asbestos layer (6a) of
A second low resistance paint layer (7b) is formed by coating a length of m. Next, wind the ferrous asbestos tape from a position 20 m away from the assumed iron core end line (A), that is, from above the second low-resistance paint layer (7b) to a position 89 m longer than the first ferrous asbestos layer (6a). , second ferrous asbestos layer (6b)
form. Next, the epoxy phenol is applied from a position 80 stitches away from the assumed iron core end line (4) to the outer peripheral tip of the second iron-containing asbestos layer (6b), and the first varnish coating layer (
Form 8a). Next, the low-resistance paint is applied to a length of 30m on the second ferrous asbestos layer (6b) from a position 20m away from the assumed iron core end line to form a third low-resistance paint layer (7c). do. Next, 2 from the assumed iron core end line (A)
01111L distant position, that is, the third low resistance paint layer (7c
), wind the iron-containing asbestos tape for a further 150 m on top of the second ferrous asbestos layer (6b), and then
A ferrous asbestos layer (6C) is formed. Next, the epoxy phenol is applied from the assumed iron core end line (a position 80 m away from the line) to the tip of the outer periphery of the third iron-containing asbestos layer (6c) to form a second varnish coating layer (8b).

A non-adhesive tape is wound around the entire wire ring, and the wire is placed in a vacuum pressurized heating tank. After being evacuated, the wire is heated under pressure to form a semi-cured prepreg-like insulating layer (4) and the first and second varnishes. The phenolic coating layers (sa) and (8b) are cured.

The first, second, and third iron-containing asbestos layers (6a), (6b), and (6c) thus formed;
The layer consisting of the third low resistance paint layer (7a), (7b), (7c) and the first and second varnish coating layers (8a), (8b) is called the high resistance corona shield layer (6). do.

Next, remove the non-adhesive tape, and apply 408 parts on the hardened insulating layer (4) from the part that reaches inside the slot to the outside of the expected line at the core end.
Asbestos tape (Tetron tape or glass tape may also be used, which can be selected depending on the heat-resistant application) is used to protect the insulating layer (4) and to stabilize the resistance value of the low-resistance paint for slot corona prevention that will be applied. ) to form a protective tape layer (9). Next, a low resistance paint for preventing slot corona is applied on this protective tape layer (9), and a low resistance corona shield layer for preventing slot corona (
5) Form.

Although the corona shield layers (5), (6), etc. are shown thick in FIG. 2, this is done for convenience of illustration, and they are actually thin.

Next, the effect will be explained.

Since the iron-containing asbestos tape is flexible, it can be wound around the curved part (2c) K of the wire ring (2) well.

Then, when heating the prepreg-like insulating layer (4) and the first and second varnish coating layers (8m) and (8b) under vacuum pressure,
When the first iron-containing asbestos layer (6a) K is coated with varnish directly, the surface from the insulating layer (4) soaks in to maintain a moderately high resistance. If the epoxy film is applied to the Ml iron-containing asbestos layer (6a), the resistance value of the high-resistance corona shield layer (6) will be too high and it will not be a good corona shield layer. Then, the first and second varnish coating layers (8a), (8
By making the face used to form b) the same as the epoxy face contained in the insulating layer (4), the curing reaction during curing of the epoxy resin is the same, so the insulating layer (
4) and the high-resistance corona shield layer are integrated to form a good corona shield layer without any minute gaps. In addition, the first and second varnish coating layers (8g), (8g)
b) as the first, second and third low resistance paints (7a) and (7b
), (7c) from the end (80-20-30) = 30m
The part that was separated is the high-resistance corona shield layer near the end of the core (6)
This is to prevent the corona shield layer (6) from halving its role if the resistance value of the corona shield layer (6) is too high. This is permissible up to a minimum of 20 meters, but if it exceeds a maximum of 80 m, the range of low resistance is too long and becomes too long to serve as a high-resistance corona shield layer. The end positions of the first, second, and third iron-containing asbestos layers (6a), (6h), and (6c) are different in order to gently distribute the surface potential distribution, and the test results are as follows: It will look like curve C in Figure 4. In other words, Fig. 4 shows the winding of tin foil around the part of each insulated wire ring that should be inserted into the core slot to form a ground.When a 50 Hz AC voltage of 45 kV is applied between the wire ring conductor and the ground, the tip of the tin foil in front of the end of the tin foil is shown. FIG. 3 is a curve diagram showing the coil surface potential as a percentage for each length position on the coil end side.

Curve A shows the case without a high-resistance shield layer, and the surface potential rises rapidly near the edge of the tin foil, so bad that there is no room to take into account the total heat, and the visible corona generation voltage is 4.0 to 6.
It was OKV. Curve B is for a conventional ferrous asbestos type high-resistance corona shield layer with a length of 350th insulated wire, and the potential distribution is uniform and strong, with a high rate of increase near the tin foil edge, and then saturation. It rises rapidly from near the edge of the ferrous asbestos layer. The sudden rise in the voltage is bad for corona resistance, and the visible corona generation voltage is 47. OkV
Met.

On the other hand, in the case of the insulated wire ring of this example, the surface potential distribution is close to a straight line (and gently distributed, as shown by the curve CK), indicating that the corona resistance property is good, and it is actually visible. I measured the voltage that generates 65.O
It was an excellent result of kV. The curve is for Example 2, which will be described later. Then, the insulated wire ring of Example 1 was housed in the stator core of a turbine generator, the ends of the wire wire were tightly and intricately fixed, and a 50 Hz alternating current was applied between the wire wire conductor (3) and the iron core (not shown). A withstand voltage test was conducted by applying a voltage of 50.5 kV, but no visible creeping corona was observed. In other words, it was confirmed that it passed the test as an insulated wire ring with a rated voltage of 2a kV.

Example 2 Next, a second embodiment will be described with reference to FIG.

First, 20 parts by weight of Epicor 828 (trade name manufactured by Shell) as an epoxy resin, 20 parts by weight of Epicor 1001 (trade name manufactured by Shell), and 30 parts by weight of Nadizuku methyl anhydride as an acid anhydride curing agent. An epoxy-based face is manufactured by mixing 30 parts of toluene. Next, 20'% or more of the epoxy face by weight is applied to the mica sheet, heated and dried to produce a prepreg mica sheet, and this is cut into tapes. This prepreg mica tape is wound around the wire conductor (3) a predetermined number of times to form a prepreg-like insulating layer (4). Next, apply 15 cm of the same low-resistance paint as the low-resistance paint for slot corona prevention layer formation from a position 108 cm away from the assumed iron core end line (A).
The first low-resistance paint layer (7a) is formed by coating a length of 111.

Next, from a position 5s+s away from the iron core end assumed line (A),
over the first low resistance paint layer (7a), 2501
Wrap the iron-containing asbestos tape to a length of 11+ and
A ferrous asbestos layer (6j) is formed. Since the curved part (2c) of the wire ring (2) is located approximately 100 m from the assumed core end wire body, the first ferrous asbestos layer (6a) naturally extends beyond the curved part (2c). It has reached the middle of part (2b). Next, from a position 10 meters away from the assumed iron core end line (A), 15 m above the first iron-containing asbestos layer (6a).
The low-resistance paint is applied to the length of , forming a second low-resistance paint layer (7b). Next, IO from the iron core end assumed line (A)
A ferrous asbestos tape is wound to a length of 150 m over the second low-resistance paint layer (7b) and the first ferrous asbestos layer (6a) from a position n apart from the second ferrous asbestos layer (6b). form. The epoxy-based face is applied onto the second iron-containing asbestos layer (6b) from a position 50N apart from the assumed iron core end line to the end to form a first face coating layer (8a). Next, the iron core end assumed line (A)
The low-resistance paint is applied to a length of 15 lengths on the second iron-containing asbestos layer (6h) from a position 10191 degrees away from the base to form a third low-resistance paint layer (7c). Next, from a position 15N away from the assumed iron core end line (4), the third low-resistance paint layer (7c), the 20th iron-containing asbestos layer (6b)
, over the first face coating layer (8a).
), wind the ferrous asbestos tape to a length of approximately 908 cm to the vicinity of the bend (2c), and wrap the third ferrous asbestos layer (6c).
) to form. The third ferrous asbeth) layer (6c)
The epoxy-based face is applied from a position 50 mm away from the assumed iron core end line (A) to the end to form a second face coating layer (8b).

Next, this coil was coated with a semi-cured insulating layer (
4) and the high-resistance corona shield layer (6) are cured.

Next, on the hardened insulating layer (4), from the part that will be inside the slot to the assumed iron core end line (15 fins outside Al), overlay the insulating layer by 5 m on top of the third low-resistance paint layer (7c). (4
) and to stabilize the resistance value of the low-resistance paint for preventing slot corona that will be applied from now on, a protective tape layer (9) is formed by winding 1 Tetron tape.

Next, a low resistance paint for preventing slot corona is applied on this protective tape layer (9) to form a low resistance corona shield layer for preventing slot corona (5).

Next, the effect will be explained.

According to the second embodiment, the same effects as in the first embodiment are achieved, and the surface potential distribution curve is reduced by 1/1 as shown in the curve of FIG. That is, although the surface potential distribution is higher than that of Example 1 shown by curve C, it is similar to curve C in that it is distributed almost linearly. And the visible corona generation voltage is 61k
V, which was slightly lower than that of Example 1.

The classification of insulated coils having the characteristics of each curve in FIG. 4 explained above is tabulated as shown in Table 1 below.

In Table 1, the visible corona was observed at the end of the longest asbestos layer for curves B, C, and D, which had iron-containing asbestos layers.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings; for example, the iron-containing asbestos layer may have two layers, or may have more layers. It goes without saying that various modifications can be made without modification.

〔Effect of the invention〕

As explained above, according to the present invention, when the prepreg insulating layer is cured, the innermost ferrous asbestos layer is impregnated with a moderate amount of varnish from the prepreg insulating layer, and the ground insulating layer in which one prepreg insulating layer is cured, The resistance corona shield layer and the resistive corona shield layer were designed to be one piece with no small gaps, and the winding length of each iron-containing asbestos layer was changed to gently increase the surface potential distribution and make it close to a straight line. It is possible to manufacture insulated coils for Hiko high-voltage rotating electric machines with good corona shielding effect.

[Brief explanation of the drawing]

FIG. 1 is an elevational view showing the main parts of a rotating electrical machine insulated wire produced by a conventional method, and FIGS. 2 and 3 are respectively produced by different embodiments of the method of the present invention. FIG. 4 is a sectional view showing the main part of the ring, and a curve diagram showing the surface potential distribution at the end of various insulated wire rings. 1... Iron core 1a... Slot 2... Insulated wire ring 2a... Straight section 2b...
- Curved portion 2c... Curved portion 3... Wire conductor 4... Insulating layer 5... Low resistance corona shield layer for slot corona prevention 6... High resistance corona shield layer 6a, 6b, 6c ...First, second, and third iron-containing asbestos layers 7a, 7b, 7c...First, second, and third low-resistance paint layers 8a, 8b...First and second face coating layer 9
...Protective tape layer Person ... Iron core end assumed line representative Patent attorney Inoue-Male Figure 1

Claims (1)

[Claims] A prepreg insulating layer is provided by wrapping prepreg insulation tape around the wire ring conductor, which has a straight part and a curved part that transitions from the straight part to the curved part outside the core. Beyond the 9th section of the song from a position a predetermined distance away,
A plurality of layers of ferrous asbestos are provided by winding ferrous asbestos tape on the prepreg insulating layer with different lengths from the bending part. At this time, each ferrous asbestos layer has a portion close to the iron core attached to the counter insulating layer and each layer. A low-resistance paint layer coated with a paint with lower resistance than ferrous asbestos is provided between the layers, and prepreg insulating tape is placed on the outside of each of the second and higher ferro-containing asbestos layers at a distance of 20 to 80 wires from the low-resistance paint layer. The same ferrous asbestos used in the above is applied to form a ferrous coating layer, and the wire is heated under vacuum pressure to harden the prepreg insulating layer, and at the same time, the ferrous asbestos is infiltrated into each layer of the prepreg insulating layer to form a high resistance layer. A corona shield layer is formed, and then a low-resistance corona shield layer having a lower resistance than the high-resistance corona shield layer is provided from the part where the straight part is inserted into the core to the vicinity of the outer middle part of the position where the low-resistance paint layer is provided. A method of manufacturing an insulated wire ring for a rotating electrical machine, characterized by: