A generator stator bar insulation structure

Abstract

This utility model relates to an insulation structure for generator stator bars, including a straight section insulation component and an inclined end insulation component. The straight section insulation component includes a first glass fiber yarn insulation layer and a composite felt insulation pad. A first mica strip insulation layer is embedded in the transposition recess. The outer end faces of the stator bars have second mica strip insulation layers. The outer side of the straight section of the stator bars is entirely wrapped with a first mica tape, and a low-resistance anti-corona layer is wrapped around the outside of the first mica tape. The inclined end insulation component includes a second glass fiber yarn insulation layer and NOMEX paper. The outer side of the inclined end of the stator bars is entirely wrapped with a second mica tape, and a covering tape is wrapped around the outside of the second mica tape. A medium-high resistance anti-corona layer is wrapped around the connection between the first and second mica tapes. This utility model has the following advantages: a double insulation barrier is set at the transposition recess, strengthening the insulation at the transposition recess; the composite felt insulation pad can absorb the vibration energy of the straight section; and the tear resistance of the NOMEX paper effectively restrains end deformation.

Description

Technical Field

[0001] This utility model belongs to the field of stator bar insulation, specifically relating to a generator stator bar insulation structure. Background Technology

[0002] The stator bar insulation structure plays a crucial role in the stator structure. It ensures electrical safety, prevents leakage and short circuits; improves motor performance, optimizes the electric field, and reduces losses; it also enhances mechanical stability, adapts to the operating environment, and extends the service life of the bars.

[0003] The existing stator bar insulation structure has the following technical defects: 1. The outside of the transposition recess is fixed with mica tape by adhesive, and then the outside of the stator bar is wrapped with mica tape, and then the outside of the mica tape is wrapped with an anti-corona layer. There is a certain air gap at the transposition recess. The presence of the air gap makes it easier for current to pass through, thereby reducing the insulation resistance at the transposition recess, weakening the insulation performance, increasing the risk of generator leakage, and at the same time, the air gap will destroy the original uniform electric field distribution of the stator bar, accelerating insulation aging and damage; 2. Ordinary epoxy gaskets are usually used between the straight parts of the stator bar. Vibration can easily cause the gaskets to pulverize, the flat copper wire plate to shift, and wear the insulation layer. Glass fiber gaskets are used between the inclined ends. Under bending stress, micro-cracks or deformation are easily generated, reducing the insulation life. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a generator stator bar insulation structure. A double insulation barrier is set at the transposition recess to strengthen the insulation at the transposition recess, optimize the electric field distribution, and suppress partial discharge. The composite felt insulation pad can absorb the vibration energy of the straight section, and the tear resistance of NOMEX paper effectively restrains the end deformation.

[0005] The objective of this utility model is achieved through the following technical solution: a generator stator bar insulation structure, wherein the stator bar is a double-layer structure formed by sequentially winding and weaving multiple flat copper wire plates. Each flat copper wire plate includes a straight section and inclined ends located on both sides of the straight section. Each flat copper wire plate has a front transposition protrusion and a back transposition protrusion on its straight section, and the distance between the front and back transposition protrusions on each flat copper wire plate is consistent. The front transposition protrusions on adjacent flat copper wire plates are staggered by a distance 'a'. The insulation structure reinforces the multiple flat copper wire plates to form a complete stator bar structure. The outer end face of the stator bar has transposition recesses located inside the front and back transposition protrusions. The structure includes a straight section insulation component and an inclined end insulation component. The straight section insulation assembly includes a glass fiber yarn insulation layer 1 covering the outside of the straight section and a composite felt insulation pad placed between the upper and lower double straight sections. A mica strip insulation layer 1 is embedded in the transposition recess. The outer end faces of the stator bar have a mica strip insulation layer 2. The outer side of the straight section of the stator bar is entirely wrapped with a mica tape 1. A low-resistance anti-corona layer is wrapped around the outside of the mica tape 1. The inclined end insulation assembly includes a second layer of glass fiber yarn insulation covering the outside of the inclined end and NOMEX paper placed between the upper and lower double-layer inclined ends. The outer side of the inclined end of the stator bar is entirely wrapped with a second layer of mica tape. The outside of the second layer of mica tape is wrapped with a covering tape. The outside of the connection between the first and second layers of mica tape is wrapped with a medium-high resistance anti-corona layer. The medium-high resistance anti-corona layer is placed between the covering tape and the low resistance anti-corona layer.

[0006] A further improvement of this utility model is that the composite felt insulating pad consists of two layers of top-adhesive felt and an epoxy glass cloth sheet placed between the two layers of top-adhesive felt.

[0007] A further improvement of this utility model is that the upper and lower layers of adhesive felt and epoxy glass cloth sheet are bonded together by vacuum hot pressing to form an integral composite felt insulation pad.

[0008] A further improvement of this utility model is that the epoxy glass cloth sheet is made by drying glass fiber cloth impregnated with epoxy resin.

[0009] A further improvement of this utility model is that the covering tape is made by heating and curing a glass fiber tape impregnated with epoxy resin semiconductor paint.

[0010] This utility model has the following advantages compared with the prior art: 1. The straight section and inclined end of this utility model use glass fiber yarn layers, which can not only resist electromagnetic vibration, but also adapt to end bending stress. A composite insulation barrier is formed by mica tape, low-resistance anti-corona layer, medium-high resistance anti-corona layer and covering tape, which can maintain the overall insulation performance while withstanding thermal expansion stress. Secondly, a mica strip insulation layer one is embedded in the transposition pit, and a mica strip insulation layer two is provided on the outer end face to reduce the air gap. The high breakdown field strength of mica material can effectively block the electric field concentration at the transposition point, reduce the risk of partial discharge, and further improve the insulation performance of the stator bar insulation structure.

[0011] 2. In this utility model, composite felt insulating pads are used between the straight sections, and NOMEX paper is embedded between the inclined ends. Combined with the wrapping of glass fiber yarn insulation layer one, glass fiber yarn insulation layer two, mica tape one, and mica tape two, a three-dimensional support system is formed. The high compression resilience of the composite felt insulating pads can absorb vibration energy, and the tear resistance of the NOMEX paper effectively restrains the end deformation, thereby improving the mechanical strength and vibration resistance of the generator stator bar insulation structure.

[0012] 3. In this utility model, the stator bar adopts a regional anti-corona design to suppress electro-corrosion. In the straight section, a low-resistivity anti-corona layer covers the mica strip one to avoid the corona initiation voltage being too low. At the connection between the mica strip one and the mica strip two, a medium-high resistance anti-corona layer is wrapped to match the change in electric field strength from the straight section to the inclined end, adaptively adjust the local field strength, and prevent discharge at the junction. The covering strip at the end forms a high-resistivity layer to suppress surface discharge caused by electric field distortion at the end. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the flat copper wire plate in this utility model.

[0014] Figure 2 This is a schematic diagram of the stator bar without insulation in this utility model.

[0015] Figure 3 This is a schematic diagram of the stator bar with the insulation structure installed in this utility model.

[0016] Figure 4 for Figure 3 A cross-sectional view of the structure along the AA direction.

[0017] Figure 5 for Figure 4 A schematic diagram of the structure of a composite felt insulating pad.

[0018] Figure 6 for Figure 3 Sectional view of the structure along the BB direction.

[0019] Numbering on the map: 10-Flat copper wire plate, 20-Straight section, 30-Inclined end, 40-Front-side transposition protrusion, 50-Back-side transposition protrusion, 60-Transposition recess; 2-Straight section insulation assembly; 3-Insulation assembly at the inclined end; 21-Glass fiber yarn insulation layer one, 22-Composite felt insulation pad, 23-Mica strip insulation layer one, 24-Mica tape one, 25-Low resistance anti-corona layer, 26-Mica strip insulation layer two; 221-Glued felt, 222-Epoxy glass cloth sheet; 31-Glass fiber yarn insulation layer II, 32-NOMEX paper, 33-Mica tape II, 34-Covering tape, 35-Medium-high resistance tape anti-corona layer. Detailed Implementation

[0020] To enhance understanding of this utility model, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. These embodiments are only used to explain the present utility model and do not constitute a limitation on the scope of protection of the present utility model.

[0021] In the description of this utility model, it should be understood that the terms indicating orientation or positional relationship, such as those based on the orientation or positional relationship shown in the drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] In this utility model, unless otherwise explicitly specified and limited, terms such as “connection,” “provided with,” and “have” should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can be described as a mechanical connection, a direct connection, or a connection through an intermediate medium. Those skilled in the art can understand the basic meaning of the above terms in this utility model according to the specific circumstances.

[0023] A generator stator bar insulation structure, with reference to Figures 1 to 3 The stator bar is a double-layer structure formed by interweaving multiple flat copper wire plates 10. Each flat copper wire plate 10 includes a straight section 20 and inclined ends 30 on both sides of the straight section 20. Each flat copper wire plate 10 has a front transposition protrusion 40 and a back transposition protrusion 50 on its straight section. The distance between the front transposition protrusion 40 and the back transposition protrusion 50 on each flat copper wire plate 10 is the same. The front transposition protrusions 40 on adjacent flat copper wire plates 10 are staggered by a distance a. An insulation structure reinforces the multiple flat copper wire plates 10 to form a complete stator bar structure. The outer end face of the stator bar has a transposition recess 60 located inside the front transposition protrusion 40 and the back transposition protrusion 50. The insulation structure includes a straight section insulation component 2 and an inclined end insulation component 3. Reference Figure 4 The straight section insulation assembly 2 includes a glass fiber yarn insulation layer 21 covering the outside of the straight section 20 and a composite felt insulation pad 22 placed between the upper and lower double straight sections 20. A mica strip insulation layer 23 is embedded in the transposition recess. The outer end faces of the stator bar have a mica strip insulation layer 26. The outer side of the straight section 20 of the stator bar is wrapped with a mica tape 24. A low-resistance anti-corona layer 25 is wrapped around the outside of the mica tape 24. Reference Figure 6 The inclined end insulation component 3 includes a glass fiber yarn insulation layer 31 covering the outside of the inclined end 30 and NOMEX paper 32 placed between the upper and lower double-layer inclined ends 30. The outer side of the inclined end 30 of the stator bar is entirely wrapped with mica tape 33. A covering tape 34 is wrapped around the outside of the mica tape 33. A medium-high resistance anti-corona layer 35 is wrapped around the connection between the mica tape 24 and the mica tape 33. The medium-high resistance anti-corona layer 35 is placed between the covering tape 34 and the low resistance anti-corona layer 25.

[0024] The straight section 20 and the inclined end 30 of this invention are respectively made of glass fiber yarn, which can not only resist electromagnetic vibration, but also adapt to end bending stress. A composite insulation barrier is formed by mica tape, low-resistance anti-corona layer 25, medium-high resistance anti-corona layer 35 and covering tape 34, which can withstand thermal expansion stress while maintaining overall insulation performance. Secondly, a mica strip insulation layer 23 is embedded in the transposition recess 60, which, together with the mica strip insulation layer 26 on the outer end face, reduces the air gap. The high breakdown field strength of the mica material can effectively block the electric field concentration at the transposition point, reduce the risk of partial discharge, and further improve the insulation performance of the stator bar insulation structure.

[0025] In this invention, a composite felt insulating pad 22 is used between the straight sections, and NOMEX paper 32 is embedded between the inclined ends 30. Combined with the wrapping of glass fiber yarn insulation layer 1 21, glass fiber yarn insulation layer 2 31, mica tape 1 24 and mica tape 2 33, a three-dimensional support system is formed. The high compression resilience of the composite felt insulating pad 22 can absorb vibration energy, and the tear resistance of the NOMEX paper 32 effectively restrains the end deformation, thereby improving the mechanical strength and vibration resistance of the generator stator bar insulation structure.

[0026] In this invention, the stator bar is designed with a regional anti-corona layer to suppress electro-corrosion. In the straight section 20, a low-resistivity anti-corona layer 25 covers the mica strip 24 to prevent the corona initiation voltage from being too low. At the connection between the mica strip 24 and the mica strip 33, a medium-high resistance anti-corona layer 35 is wrapped to match the change in electric field strength from the straight section 20 to the inclined end 30, adaptively adjust the local field strength, and prevent discharge at the junction. The end covering strip 34 forms a high-resistivity layer to suppress surface discharge caused by electric field distortion at the end.

[0027] Based on this embodiment, refer to Figure 5 The composite felt insulating pad 22 consists of two layers of adhesive felt 221 and an epoxy glass cloth sheet 222 placed between the two layers of adhesive felt 221.

[0028] Furthermore, the upper and lower layers of adhesive felt 221 and epoxy glass cloth sheet 222 are vacuum hot-pressed together to form an integral composite felt insulating pad 22.

[0029] Furthermore, the epoxy glass cloth sheet 222 is made by drying glass fiber cloth impregnated with epoxy resin.

[0030] The technical advantages of the composite felt insulating pad 22 in this application are as follows: 1. The composite felt insulating pad 22 integrates the adhesive felt 221 and the epoxy glass cloth sheet 222 into a single structure through a vacuum hot-pressing process. The epoxy glass cloth sheet 222 can withstand the electromagnetic force impact between the wire rod layers, preventing displacement of the flat copper wires. At the same time, the elastic modulus of the adhesive felt 221 provides flexible buffering, absorbing vibration energy during operation.

[0031] II. The epoxy resin impregnation process of epoxy glass cloth sheet 222 makes its dielectric strength much higher than that of ordinary mica tape. The synergistic effect of the main insulation layer of the stator bar and the impregnation pit 60 blocks the air gap electric field distortion, increases the partial discharge initiation voltage, and improves the insulation reliability.

[0032] Based on this embodiment, the covering tape 34 is a glass fiber tape impregnated with epoxy resin semiconductor paint and cured by heating.

[0033] Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An insulation structure for a generator stator bar, wherein the stator bar is a double-layer structure formed by sequentially winding and braiding multiple flat copper wire plates, each flat copper wire plate comprising a straight portion and inclined ends on both sides of the straight portion, each flat copper wire plate having a front transposition protrusion and a back transposition protrusion on its straight portion, and the distance between the front transposition protrusion and the back transposition protrusion on each flat copper wire plate being the same, the front transposition protrusions on adjacent flat copper wire plates being staggered by a distance a, the insulation structure reinforcing multiple flat copper wire plates to form a complete stator bar structure, the outer end face of the stator bar having a transposition recess located inside the front transposition protrusion and the back transposition protrusion, characterized in that: Including straight section insulation components and inclined end insulation components, The straight section insulation assembly includes a glass fiber yarn insulation layer 1 covering the outside of the straight section and a composite felt insulation pad placed between the upper and lower double straight sections. The transposition recess is embedded with a mica strip insulation layer 1. The outer end faces of the stator bar have a mica strip insulation layer 2. The outer side of the straight section of the stator bar is entirely wrapped with a mica tape 1. The outside of the mica tape 1 is wrapped with a low-resistance anti-corona layer. The inclined end insulation assembly includes a second glass fiber yarn insulation layer covering the outside of the inclined end and NOMEX paper placed between the upper and lower double-layer inclined ends. The outer side of the inclined end of the stator bar is entirely wrapped with a second mica tape. The outside of the second mica tape is wrapped with a covering tape. The outside of the connection between the first mica tape and the second mica tape is wrapped with a medium-high resistance anti-corona layer. The medium-high resistance anti-corona layer is placed between the covering tape and the low resistance anti-corona layer.

2. The generator stator bar insulation structure according to claim 1, characterized in that: The composite felt insulating pad consists of two layers of top-coated felt and an epoxy glass cloth sheet placed between the two layers of top-coated felt.

3. The generator stator bar insulation structure according to claim 2, characterized in that: The upper and lower layers of adhesive felt and epoxy glass cloth sheet are bonded together by vacuum hot pressing to form an integral composite felt insulation pad.

4. The generator stator bar insulation structure according to claim 3, characterized in that: The epoxy glass cloth sheet is made from glass fiber cloth impregnated with epoxy resin and then dried.

5. The generator stator bar insulation structure according to claim 4, characterized in that: The covering tape is made by heating and curing glass fiber tape impregnated with epoxy resin semiconductor paint.

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