JP2017060321A - Rotary electric machine coil and rotary electric machine - Google Patents

Abstract

It is possible to prevent the material from peeling off due to thermal stress as necessary and to relieve mechanical stress at a conductor corner.
A rotating electrical machine coil according to an embodiment includes a conductor having a corner, a main insulating layer, a semiconductive member disposed between the conductor and the main insulating layer, and the conductor and the semiconductive member. And a stress relaxation member having an elastic modulus at a corner portion of the conductor of 100 MPa or less.
[Selection] Figure 3

Description

  Embodiments described herein relate generally to a rotating electrical machine coil and a rotating electrical machine.

  In the stator coil housed in the slot formed on the inner diameter side of the iron core of the high-voltage rotating electrical machine, the operating temperature is high, and the starting and stopping of the rotating electrical machine is frequently repeated, so that, for example, the metal material of the stator coil The thermal stress resulting from the difference in coefficient of linear expansion between the insulating material and the insulating material is generated, and these materials may be separated. The following five may be considered as places where there is a possibility of peeling. That is, (1) between the iron core and the stator coil, (2) between the slot and the external corona prevention layer, (3) between the external corona prevention layer and the main insulating layer, and (4) inside the main insulating layer. (5) between the main insulating layer and the inner corona shield, and (6) between the inner corona shield and the conductor.

  (2) Between the slot and the external corona prevention layer, if the external corona prevention layer having semiconductivity is electrically connected to the iron core other than the part where the peeling occurs, the coil side potential is grounded. Since it can be maintained near the potential of the iron core, damage due to the occurrence of corona discharge can be avoided.

  In addition, active measures are taken to prevent peeling between (1) the iron core and the stator coil, (3) between the outer corona prevention layer and the main insulating layer, and (4) the gap inside the main insulating layer. In order to maintain the electrical connection while relaxing the thermal stress by causing the separation, and the method using the conductive tetrafluoroethylene tape, and the material that relieves the thermal stress of both, the peeling itself And a method for realizing electrical connection by providing a semiconductive layer on both the main insulating layer surface and the inner surface of the slot.

JP-A-56-83237 Japanese Patent No. 3284593 JP-A-9-149578 JP-A-9-182343

The method as described above has the following problems.
In these methods, among the above-described peeling problems, (1) between the iron core and the stator coil, (2) between the slot and the external corona prevention layer, (3) the external corona prevention layer and the main insulating layer, And (4) the internal gap of the main insulating layer can be removed, but (5) between the main insulating layer and the inner corona shield, and (6) between the inner corona shield and the conductor. In the meantime, countermeasures against peeling are insufficient. Even if the above problems (1) to (4) are solved, if peeling occurs in other parts, it is difficult to say that insulation measures are finally necessary and sufficient.

  Further, in the stator coil having a long iron core length and the rotor coil of the variable speed pumped-storage generator motor, compressive stress and shear stress are applied to the insulating layer at the end of the iron core due to thermal elongation. In that case, the effect of the said countermeasure is inadequate and peeling may arise. Furthermore, due to stress concentration at the conductor corner, cracks and the like are introduced into the insulating layer, which may lead to a ground fault.

  In order to solve the above problems, the above-mentioned (5) the peeling between the main insulating layer and the inner corona shield and the above-mentioned (6) the inner corona shield and the conductor are solved, and the corner portion of the conductor is solved. There is a need for a method of relieving stress in

  The object of the present invention has been made in consideration of the above-mentioned circumstances, and it is necessary to sufficiently and sufficiently prevent the material from being peeled off due to thermal stress and to relieve the mechanical stress at the conductor corner and the rotating electric coil. It is to provide an electric machine.

  The rotating electrical machine coil according to the embodiment includes a conductor having a corner, a main insulating layer, a semiconductive member disposed between the conductor and the main insulating layer, and between the conductor and the semiconductive member. And a stress relaxation member having an elastic modulus at a corner of the conductor of 100 MPa or less.

  According to the present invention, it is possible to prevent the material from peeling off due to thermal stress, and to relieve the mechanical stress at the conductor corner.

The figure which showed typically the internal structure of the general stator coil. The figure which showed typically the upper right end enlarged view about the internal structure of a common stator coil. The figure which showed typically the upper right end part enlarged view about the internal structure of the stator coil in embodiment. The figure which showed an example of the dielectric loss characteristic of the stator coil in embodiment in a graph format. The figure which showed an example of the dielectric loss characteristic of the stator coil in embodiment in a tabular form. The figure which showed typically the upper right end part enlarged view about the internal structure at the time of providing the sliding stress relaxation layer in the surface of the stator coil in embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
(Constitution)
This embodiment relates to a stator coil that can be housed in a slot on the outer peripheral side of an iron core of a high-voltage rotating electrical machine such as an induction motor or a generator, and can be fixed to the slot by a wedge. The stator coil resin impregnation method is roughly classified into a vacuum pressure impregnation (VPI (Vacuum Pressure Impregnation)) insulation method and a resin rich (RR (resin-rich)) insulation method. In the present embodiment, the coil is manufactured using a resin rich (RR) insulation method having a lower environmental load.

FIG. 1 is a diagram schematically showing the internal structure of a general stator coil. FIG. 2 is a diagram schematically showing an enlarged view of the upper right end of the internal structure of a general stator coil.
As shown in FIGS. 1 and 2, the stator coil 10 is generally configured by laminating an inner corona shield 3 for preventing corona discharge and a main insulating layer 2 in this order on a conductor 4. .

FIG. 3 is a diagram schematically showing an enlarged upper right end portion of the internal structure of the stator coil in the embodiment.
As shown in FIG. 3, in this embodiment, stress relaxation layers (stress relaxation materials) 8 are provided between the conductor 4 and the inner corona shield 3 and between the inner corona shield 3 and the main insulating layer 2, respectively. Provided. The stress relaxation layer 8 may be provided only between the conductor 4 and the inner corona shield 3.

  Examples of the stress relaxation material according to the present embodiment include (A) sheet-like material, (B) tape-like material, and (C) paint-like material (coating material). In this embodiment, (A) the sheet-like material is defined as a wide and thin paper-like material, and (B) the tape-like material is defined as a narrow and thin strip-like material, (C) The paint-like material is defined as a material used by applying to the surface by various coating methods.

  (A) Examples of the sheet-like material include a sheet having high heat resistance, and a material in which a glass cloth, a silicone pressure-sensitive adhesive, and a release film are provided on both sides of a silicone base sheet.

(B) The tape-like material is a tape having high heat resistance, and (A) a material in which a glass cloth, a silicone pressure-sensitive adhesive, and a release film are provided on both sides of a silicone-based tape, as in the case of a sheet-like material. Etc.
Examples of the paint-like material (C) include materials having high heat resistance, which can be cured by heating or treating at room temperature for a predetermined time.

(Method)
Next, a method for manufacturing the stator coil in the embodiment will be described.
First, a copper conductive wire serving as a conductor is cut into a predetermined length, and then the insulation coating on both ends is removed. Thereafter, a predetermined number of wires are bundled, and a coil is formed through a label transition process. Next, a coil is formed by heat press, and this coil is formed into an involute type, whereby the conductor 4 having a corner portion of the stator coil 10 is obtained.

  Thereafter, the semi-conductive internal corona shield 3 is installed around the conductor 4, the main insulating layer 2 is taped by a taping machine, and the semi-conductive external corona prevention layer (not shown) is taped. . Next, the stator coil 10 is completed by installing a steel backing plate and a laminate and joining the coils together by a resin impregnation process using a resin rich insulation method.

  Here, in the present embodiment, the stress relaxation layer 8 is provided before the inner corona shield 3 is installed around the conductor 4 and before the main insulating layer 2 is taped around the inner corona shield 3. That is, the stress relaxation layer 8 is provided between the conductor 4 and the inner corona shield 3 and between the inner corona shield 3 and the main insulating layer 2.

  Here, the material of the stress relaxation layer 8 between the conductor 4 and the inner corona shield 3 has an elastic modulus at the corner of the conductor 4 so that mechanical stress at the corner of the conductor 4 of the stator coil 10 can be relaxed. The material is 100 MPa (megapascal) or less.

The case where the stress relaxation layer 8 is said (A) sheet-like material is demonstrated. When this sheet-like material has an adhesive layer, the stress relaxation layer 8 is installed so as to cover the conductor 4 and the internal corona shield 3 via this adhesive layer. When the sheet-like material does not have an adhesive layer, the stress relaxation layer 8 is installed by taping the sheet-like material with a predetermined taping material in a state where the sheet-like material is applied to the installation surface.
When the stress relaxation layer 8 is the above-mentioned (B) tape-shaped material, the stress relaxation layer 8 can be installed by a taping machine or manual winding.

  When the stress relaxation layer 8 is the above-mentioned (C) paint-like material, the stress is applied by applying this material around the inner corona shield 3 or around the main insulating layer 2 using brush, spray or the like. A relaxation layer 8 can be installed.

After the stress relaxation layer 8 is installed through these steps, the external corona prevention layer taping step is started through the installation of the internal corona shield 3 and the taping of the main insulating layer 2 by a taping machine as usual. The processes before and after this are the same as the general processes for manufacturing the stator coil.
The stator coil 10 is manufactured through the processes as described above.

(Function)
Next, the operation of the stress relaxation layer 8 and the sliding stress relaxation structure in the embodiment will be described.
By disposing any one of the above materials or a combination of these materials between the conductor 4 and the inner corona shield 3, peeling between the conductor 4 and the inner corona shield 3 is prevented. can do.

  Further, by disposing any one of the above materials or a material made of a combination thereof between the inner corona shield 3 and the main insulating layer 2, the inner corona shield 3 and the main insulating layer 2 Separation can be prevented.

FIG. 4 is a graph showing an example of the dielectric loss characteristic of the stator coil in the embodiment. FIG. 5 is a table showing an example of the dielectric loss characteristics of the stator coil in the embodiment.
After applying the compression load of 30 MPa along the direction between the upper surface (slot opening side) and the lower surface (opposite side of the opening side) when the stator coil 10 is housed in the slot, Dielectric loss (tan δ) characteristics were measured. As a result, as shown in FIGS. 4 and 5, better dielectric loss characteristics were obtained when the stress relaxation layer 8 was installed than when the stress relaxation layer 8 was not installed.

FIG. 6 is a diagram schematically showing an enlarged view of the upper right end of the internal structure when a sliding stress relaxation layer is provided on the surface of the stator coil in the embodiment.
In the present embodiment, in addition to the stress relaxation layer 8, the surface of the main insulating layer 2 in the vicinity of the slot opening when the stator coil 10 is housed in the slot (or the surface when an external corona prevention layer is provided). ) Can be provided with a sliding stress relaxation layer 20. The sliding stress relaxation layer 20 includes a laminate 12 and an elastic body 13, and a coating layer 11 having excellent sliding wear characteristics is provided on the surface of the laminate 12, and an elastic body as viewed from the surface of the main insulating layer 2. 13, a laminated plate 12, and a coating layer 11 are laminated in this order.

  In addition, as a result of performing the sliding wear test on the stator coil 10 provided with the sliding stress relaxation layer 20 as described above, better wear characteristics are obtained compared to the case where the sliding stress relaxation layer 20 is not provided. It was.

  The friction coefficient of the coating layer 11 of the above-described sliding stress relaxation layer 20 is desirably 0.3 or less, and particularly desirably the friction coefficient is 0.1 or less. For this reason, the coating layer 11 is preferably, for example, diamond-like carbon (DLC).

(effect)
Below, the effect by having installed the stress relaxation layer 8 is described.
In general, the linear expansion coefficient is different between the conductor 4, the inner corona shield 3, and the main insulating layer 2. The linear expansion coefficient is represented by α, and is a coefficient that increases by α μm when the temperature rises by 1 ° C. per meter. Since the linear expansion coefficient is different between the conductor 4, the inner corona shield 3, and the main insulating layer 2, peeling can occur due to different lengths of expansion and contraction in the process of heating and cooling.
Therefore, in the present embodiment, the stress relaxation layer 8 is disposed between the conductor 4 and the inner corona shield 3 and between the inner corona shield 3 and the main insulating layer 2 to absorb the stress caused by thermal expansion and contraction. And peeling can be prevented.

  Further, the material of the stress relaxation layer 8 between the conductor 4 of the stator coil and the inner corona shield 3 is made of a material having an elastic modulus at the corner of the conductor 4 of 100 MPa (megapascal) or less. The mechanical stress at the corners of the coil conductor 4 can be relaxed.

  Furthermore, by providing the sliding stress relaxation layer 20 on the surface near the opening of the slot when the stator coil 10 is housed in the slot, the sliding wear at the end of the coil core is suppressed by the thermal elongation during operation. In addition, a highly reliable rotating electrical machine coil can be provided even during long-term operation.

  The rotating electrical machine coil in the embodiment is not limited to the above-described stator coil, and can be used as, for example, a rotor coil of a variable speed pumped rotary electrical machine.

  In addition, although embodiment of this invention was described, this embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 2 ... Main insulation layer, 3 ... Internal corona shield, 4 ... Conductor, 8 ... Stress relaxation layer, 10 ... Stator coil, 11 ... Coating layer, 12 ... Laminated board, 13 ... Elastic body, 20 ... Sliding stress relaxation layer .

Claims (4)

A conductor having corners;
A main insulating layer;
A semiconductive member disposed between the conductor and the main insulating layer;
A rotating electrical machine coil comprising: a stress relaxation member disposed between the conductor and the semiconductive member and having an elastic modulus at a corner portion of the conductor of 100 MPa or less. The rotation according to claim 1, wherein a sliding stress relaxation member is provided on the surface of the main insulating layer near the opening of the slot when housed in a slot formed in the iron core of the rotating electrical machine. Electric coil. The rotating electrical machine coil according to claim 2, wherein the sliding stress relaxation member includes diamond-like carbon.   A rotating electrical machine comprising the rotating electrical machine coil according to any one of claims 1 to 3.