KR20010049158A - A rotating electric machine and method of manufacturing such a machine - Google Patents

Abstract

The present invention relates to a rotating electrical device incorporating a stator 1 and a winding drawn out through a slot 5 of the stator. According to the invention, the winding consists of a high voltage cable 6 in which a slot 5 adjacent the end plane 19 of the stator is provided with a cable in the slot and cuff members 13, 16 arranged between the walls of each slot. do. After a cuff is provided in a slot adjacent to the end plane of the stator, a method of manufacturing the rotary electric device in which a cable is withdrawn through the cuff is disclosed.

Description

Rotating electric device and manufacturing method of the device {A ROTATING ELECTRIC MACHINE AND METHOD OF MANUFACTURING SUCH A MACHINE}

In the present application, the terms "radial", "axis" and "periphery" refer to the direction defined for the stator if not expressly described. The term "cable lead-through" refers to the length of each of the cables extending through the slot.

The device is considered as a generator of a power plant for generating power. The device is intended for use at high voltages. High voltage is understood to mean a voltage exceeding 10 kV. The typical operating range of the device according to the invention is 36 to 800 kV.

Similar devices are typically designed for voltages of 6-30 kV and 30 kV is generally considered the upper limit. This generally means that the generator must be connected to the power network through a transformer that increases the voltage to a power network level in the range of approximately 100-400 kV.

When supplying current to high voltage networks for power transmission, substation, and distribution, even though most techniques insert transformers between generators and power networks as described above, attempts are made to eliminate transformers by generating voltage directly at the network level. It is known. The generator is described in US Pat. No. 4,429,244, US Pat. No. 4,164,672, and US Pat. No. 3,743,867.

Conductors in which insulation is provided to the inner and outer layers of semiconductor pyrolytic glass fibers are known from US Pat. No. 5,036,165. In addition, as described in US Pat. No. 5,066,881, a layer of semiconductor pyrolytic fiberglass contacts two parallel bars forming a conductor, and insulation of the stator slot is surrounded by a semiconductor pyrolytic fiberglass outer layer to provide insulation to the conductor of the dynamoelectric device. It is known to provide. Pyrolytic fiberglass materials are described as suitable materials because they maintain resistance even after the implantation treatment.

By using high voltage insulated electrical conductors, the voltage of the device in the next cable with solid insulation similar to that used in cables for transmitting power in stator windings (eg XLPE cables) is directly connected to the power network without intermediate transformers. Can be increased to the level to be connected.

This concept generally requires a slot, in which the cable is placed deeper in the stator than in conventional techniques (the higher the voltage and the higher the number of turns in the winding, the thicker the insulation). This creates new problems with cooling, vibration and natural frequency at the coil ends, teeth and winding areas.

Fixing the cable to the slot has the following problems-the cable must be inserted into the slot without damaging the outer layer. The cable is affected by a current having a frequency of 100 Hz in response to vibration and besides manufacturing tolerances with respect to the outer diameter, the magnitude will vary with changes in temperature (ie, load vibration).

The present invention relates to the aforementioned problem associated with avoiding damage to the outside of the cable during insertion into the stator slot and preventing wear to the surface caused by vibration during operation. If the cable is damaged against the edge between the slot and the end of the stator surface there is a risk of damage, especially at the insertion point. The cable can be damaged if it is bent or inserted eccentrically into the slot. Especially in the case of angular or centering errors, the edges rub against the outer semiconductor layer of the cable due to the relative strength of the cable, which can damage the semiconductor layer.

In a first aspect of the invention, the invention is of the type described in the preamble of claim 1, such as a synchronous device, a general asynchronous device, a double feed device, an asynchronous constant current converter cascade application, an external electrode device and a synchronous flow device. Relates to a rotary electric device.

In a second aspect of the invention the invention relates to a method of the type described in the preamble of claim 13.

1 shows a schematic end of a stator sector in an apparatus according to the invention.

2 is a cross section through a cable used in the device according to the invention;

3 is a partial cross-sectional view along the line III-III of FIG. 2;

4 is a partial cross-sectional view along the line IV-IV of FIG. 3.

For this reason, it is an object of the present invention to eliminate or at least reduce the risk of damage to the cable exiting the stator end surface of a rotating electrical device capable of working in the high voltage range.

According to a first aspect of the invention this object is achieved by providing a rotary electric device of the type described in the preamble of claim 1 with the features defined in the features of claim 1.

Cuff means reduce the risk of damage when the cable is wound because the cuff prevents the outer semiconductor layer from contacting the edge of the slot wall upon insertion of the cable and ensures that the cable is guided straight into the slot center do. The risk of damage during operation is reduced because the cuff is made of a softer material than the stator to act as a pressure equalizer.

In a preferred embodiment, the cuff means extend radially through a plurality of cable lead throws in the slot, preferably all cable lead throws, and have a profile corresponding to the profile of the slot. This makes it stable and reliably fixed.

The advantages of the present invention are particularly important when the slots have alternating wide and narrow portions, similar to magnetoelectric chains because the slot walls surround a relatively large portion of each cable lead throw. The device having the slot profile constitutes a preferred embodiment.

It is desirable to make cuff means of elastic material. The cuff means is free of processing oil and may be suitably silicone rubber. The elasticity of the material makes it easy to guide the cable and takes advantage of the opportunity to achieve pressure equalization at the outlet point over a large range.

In another preferred embodiment the cuff means are provided at the inner end with a collar protruding into the recess of the slot. This provides the cuff in a simple and economical way and keeps the cuff reliably in the slot.

To facilitate the insertion of the cable, the inner profile of the cuff is somewhat wider towards the end plane of the stator. This is provided at the normal cable outlet, reducing the risk of damage during operation.

In another preferred embodiment the cuff means are arranged to seal both the cable and the slot wall. The sealed space is formed inside the slot that can be filled with a support compound that is sprayed into the slot and solidifies therein. In some cases this is a convenient way of supporting the cable in the slot.

The present invention is first used for a high voltage cable of the type made of an inner core having a plurality of stranded portions, an inner semiconductor layer, an insulating layer surrounding the semiconductor layer, and an outer semiconductor layer surrounding the insulating layer. Remarkable here. The present invention relates to a cable having a diameter within a spacing of 20-200 mm and a conducting area within a spacing of 80-3000 mm 2.

The windings in the device according to the invention correspond to cables with solid compression molded insulators which are currently used for power distribution, for example XLPE cables or cables with EPR-insulation. The cable consists of one or more stranded portions and includes an inner conductor, an inner semiconductor layer surrounding the conductor, a solid insulation layer surrounding the semiconductor layer, and an outer semiconductor layer surrounding the insulation layer. The cable is flexible, and the flexibility is an important feature in the text because the winding system formed by the cable in which the winding is bent during assembly is based on the description of the device according to the invention. The flexibility of the XLPE cable corresponds to a radius of curvature of approximately 20 cm for a 30 mm diameter cable, and a radius of curvature of approximately 65 cm for a 80 mm diameter cable. In the present application, the term "flexible" is used to indicate that the winding is bent at a radius of curvature of four times the cable diameter, preferably on the order of 8 to 12 times the cable diameter.

The windings are configured to retain their properties when they are bent and subjected to thermal stress during operation. It is important that the cable layers are attached to each other in the specification. The material properties of the layer, in particular the elasticity and relative coefficient of thermal expansion, are important here. For example, in an XLPE cable, the insulating layer consists of low density polyethylene cross-connected and the semiconductor layer consists of polyethylene with mixed soot and metal particles. The change in volume due to temperature change is fully absorbed as a change in cable radius, and due to the relatively slight difference between the coefficients of thermal expansion of the layers with respect to the elasticity of these materials, the radial expansion may not impair the adhesion between the layers.

The above mentioned material combinations should only be considered as examples. Other combinations that meet the conditions are described and semiconductor conditions having a resistance in the range of 10 ⁻¹ −10 ⁶ ohm-cm, such as 1-500 ohm-cm, or 10-200 ohm-cm, are within the scope of the present invention. Belongs.

The insulating layer is a crosslinked material such as low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polybutylene (PB), polymethyl pentene (PMP), crosslinked polyethylene (XLPE), or ethylene propylene rubber (EPR) or a solid thermoplastic material such as silicone rubber.

The inner and outer semiconductor layers may have the same base material but have conductive material particles such as mixed chutes or metal powders.

The mechanical properties of these materials, in particular the coefficient of thermal expansion, are relatively less affected by the mixing of the chute or the metal particles, at least in proportions required to achieve the conductivity required by the present invention. Therefore, the insulating layer and the semiconductor layer have the same coefficient of thermal expansion.

Ethylene-vinyl-acetate, copolymer / nitrogen rubber, butyl graft polyethylene, ethylene-butyl-acrylate-copolymer and ethylene-ethyl-acrylate copolymer constitute polymers suitable for semiconductor layers.

Although different types of materials are used as the base of the various layers, it is preferable that their coefficient of thermal expansion is substantially the same. This is even more the case when the aforementioned materials are combined.

The material described above has a relatively good elasticity with an E-module of E <500 MPa, preferably E <200 MPa. The elasticity is sufficient for any small difference between the coefficients of thermal expansion to the layer material to be absorbed in the radial direction of the elasticity so that no cracking or other damage is seen and the layers do not fall apart from each other. The material of the layers is elastic and the adhesion between the layers is at least the same size as the one with the weakest adhesion of the materials. The conductivity of the two semiconductor layers is sufficient to make the potential substantially the same along each layer. The conductivity of the outer semiconductor layer is large enough to contain an electric field in the cable, but small enough not to cause much loss due to the current induced in the longitudinal direction of the layer.

Thus, each two semiconductor layers consist of one equipotential surface and a winding, the electric field being surrounded by these layers.

Of course, one or more additional semiconductor layers are not arranged in the insulating layer.

The present application for the cable constitutes a preferred embodiment of the present invention.

These and other preferred embodiments of the device according to the invention are limited according to claim 1.

In a second aspect of the invention, the object is achieved by a method of manufacturing a rotary electric device of the type described in the preamble of claim 19 which comprises a specific assessment defined in the features of the claims.

According to a preferred embodiment of the method, the cuff means is applied with an anti-friction medium, whereby the cable can be easily pulled out and the risk of damage during this operation can be reduced.

Cuff means according to a preferred embodiment of the device are used in another preferred embodiment of the method according to the invention.

The invention will be explained in more detail in the following preferred embodiments with reference to the accompanying drawings.

In the schematic axial view shown in FIG. 1 through the sector of the stator 1 of the device, the rotor is marked with 2. The stator typically consists of a laminated core of core sheets. The figure shows a sector of the device corresponding to one pole division. From the yoke portion 3 of the core, a number of radially outward teeth 4 extend radially inwardly towards the rotor 2, which is driven by a slot 5 in which stator windings are arranged. Are separated. The cable 6 of the winding is a high voltage cable and is the same type used for power distribution, for example a high voltage cable such as an XLPE cable. One difference is that the external mechanically protected sheath and metal screen surrounding the cable are omitted. The cable consists of a conductor, an inner semiconductor layer, an insulating layer and an outer semiconductor layer. The semiconductor layer sensitive to mechanical damage to the outer phase of the cable is exposed.

In the figure the cable 6 is schematically shown in the center, and is shown to conduct the cable part or coil side. As shown, each slot 5 has a variable cross section with alternating wide portions 7 and narrow portions 8. The wide portion 7 is substantially circular and surrounds the cable lead throw, with the waist portion between these wide portions forming a narrow portion 8. The waist portion is used to radially position each cable lead throw. The cross section of the entire slot is radially narrower inwards. This is because the voltage of the cable lead throw is lower, and the closer it is, the more the lead throw is in the radially innermost part of the stator. Therefore a thin cable lead throw is used for the innermost part, and a thicker lead throw is needed for the outer part. Three different sized cables are used in the example shown and are arranged in three sections 9, 10, 11 of the slot 5 which are suitable sizes for the cable.

2 shows a cross section of a high voltage cable 6 used according to the invention. The high voltage cable 6 has a number of stranded wire portions 31, for example made of copper (Cu), the stranded wire portions having a circular cross section. These stranded portions 31 are arranged in the middle of the cable 6. A first semiconductor layer 32 is arranged around the stranded portion 31. There is an insulating layer 33, for example, an XLPE insulator, around the first semiconductor layer 32, and a second semiconductor layer 34 around the insulating layer 33. Therefore, the concept of "high voltage cable" in this application does not include a metal screen and an outer sheath that generally surrounds the power distribution cable.

3 shows a cross section of a cuff according to the invention. The cross section is taken along line III-III of FIG. 1 and shortly extends from one end surface of the stator 1. The outer shape 15 of the cuff is similar to the slot 5, ie the bicycle chain, where the cross section extends laterally through one wide part of the “bicycle chain” as shown in FIG. The location of the cross section is shown. The cuff is arranged closely to one end 19 of the stator 1 and a similar cuff is arranged at the opposite end of the stator. The cuff extends radially along the entire slot 5 and each slot is provided with the cuff. The axial extension of the cuff is approximately 4 cm and the spacing lies within 2-6 cm. The laminated core of the stator is designed at 18 and end plates 12 of optical fiber material are arranged at their ends. The cuff is integrated into the end plate 12. The recess 17 is provided in the portion of the slot 5 extending through the end plate. The recess runs along the entire radial length of the slot 5 to the slot wall. The cuff is provided with a collar 16 suitable for the recess 17. The lining portion 13 of the cuff from the collar 16 extends toward the end surface 19 of the stator and ends just before the end surface. The cuff optionally terminates on a level with the end surface of the stator or shortly extends out of the end. The lining 13 of the cuff is closely adjacent to the slot wall along its entire length.

The interior 14 of the cuff slightly widens towards the end surface 19 of the stator at an angle of several degrees. The interior of the cuff is thus slightly conical in the area around the cable lead throw. When the cuff receives the cable 6, the smallest inner diameter adjacent to the cuff corresponds to the outer diameter of the cable 6 or is somewhat smaller to ensure good sealing and effective support. The cuff is made of an elastic material which may suitably be silicone rubber. The material does not contain any processing oil because the oil diffuses towards the outer semiconductor layer 34 of the cable, attacking and damaging the semiconductor layer. The material must be heat stable.

Between the cuffs, ie between the narrower cable locations, the cuff has a waist portion 20 (see FIG. 4) that fills the slots at these points, ensuring that it is fully charged.

When the cuff is installed before the stator is wound up, the cuff is squeezed and pushed onto the shaft towards the slot 5 until the collar 16 of the cuff is bitten into the recess 17 of the slot and locked in place. When the cuff is provided the cable is wound and the cuff serves as a guide. The cable is thus guided correctly and is prevented from contacting the edge between the end surface of the slot and the stator, thus eliminating the risk of damage. It is desirable to lubricate the inside of the cuff to facilitate insertion of the cable. Lubricants should be chosen to not affect the outer semiconductor layer of the cable. Suitable lubricants are thallium or boron nitride.

The cuff described above extends radially along the entire slot. Optionally each cuff is arranged for each cable lead throw and in this case is cylindrical. The present invention does not include cuff fastening means other than the collars described above. The collar can be glued to the slot or maintained only by friction.

Claims (21)

In a rotating electrical device incorporating a stator with a winding drawn through the slot 5 of the stator, The winding consists of a high voltage cable 6 and cuff means 13, 16 arranged between the cable 6 and the slot 5 in at least one said slot 5 on at least one end surface of the stator 1. And cuff means extend a short distance in the axial direction toward the slot. The rotary electric machine according to claim 1, characterized in that the cuff means (13, 16) comprise a cuff extending radially through all cable lead throws and having a profile of a radial section corresponding to the profile of the slot. Device. 3. A rotary electric machine according to claim 1 or 2, wherein the cuff means comprises a plurality of cuffs of circular cross section, each cuff surrounding a cable lead throw. 4. The rotary electric machine according to claim 1, wherein the slot has a profile with a wide part (7) and a narrow part (8) in a radial cross section. 5. 5. Rotary electrical device according to any one of the preceding claims, characterized in that the cuff means (13, 16) are made of an elastic material. 6. A rotary electric machine according to claim 5, wherein the material is oil free and consists of silicone rubber. 7. Cuff means (13, 16) have an axial extension of 2-6 cm and the outermost end of the cuff means is located just inside the end surface (19) of the stator. Rotating electric device, characterized in that. 8. The collar (16) according to any one of the preceding claims, wherein the cuff means (13, 16) have a collar (16) protruding at the innermost end in the axial direction from the wall of the slot to the recess (17) running radially in the plane. Rotating electrical device, characterized in that provided. 9. The cuff means 13, 16 around each cable lead throw correspond to the outer diameter of the cable 6 and extend conically toward the end plane 19 of the stator. 10. Rotating electrical device, characterized in that it has an inner profile (14) having a diameter to. 10. Rotary electrical device according to one of the preceding claims, characterized in that the cuff means (13, 16) are arranged to sealably adjoin both the slot wall (5) and the cable (6). The cable (6) according to any one of the preceding claims, wherein the cable (6) has a core having a plurality of stranded portions (31), an inner semiconductor layer (32) surrounding the core, and an insulation surrounding the inner semiconductor layer. A rotary electrical device, characterized in that it comprises a layer (33) and an outer semiconductor layer (34) surrounding the insulating layer (33). 12. Rotary electrical device according to claim 11, characterized in that the high voltage cable (6) has a diameter between 20-200 mm and a conduction area between 80-3000 mm2. 13. The rotary electric machine according to claim 11 or 12, wherein the winding is flexible and the layers are in contact with each other. The method of claim 13, wherein the layer is composed of a material having a relationship between the elasticity and the thermal expansion coefficient such that the change in the filling volume caused by the temperature change during operation is absorbed by the elasticity of the material. A rotary electric machine characterized in that the layers are attached to each other. 15. The rotary electric machine according to claim 13 or 14, wherein the material of the layer is a highly elastic material, preferably having an E module of 500 MPa or less, most preferably an E module of 200 MPa or less. 16. The rotary electric machine according to any one of claims 13 to 15, wherein the coefficient of thermal expansion of the layer material is the same magnitude. 17. The rotary electric machine according to any one of claims 13 to 16, wherein the adhesive force between the layers has an adhesive force at least equal to that of the part with the weakest adhesive force. 18. The rotary electric machine according to any one of claims 13 to 17, wherein each semiconductor layer constitutes one coincidence surface. A method of manufacturing a rotating electrical device incorporating a stator and a winding drawn through a slot of the stator, The device is wound with a high voltage cable such that the cuff means extend a short distance towards the slot and the cuff means are provided in at least one of the slots on at least one end surface of the stator, the inner size of the cuff means allowing passage of the cable and And then the cable is wound around the slot through the cuff means. 20. The method of claim 19, wherein the cuff means is painted with a non-frictional medium before the cable passes through the cuff means. 21. A method as claimed in claim 19 or 20, wherein the provided cuff means is in accordance with the embodiment as defined in any one of claims 1 to 10.