Novel stator end part fixing and ventilating structure suitable for ultrahigh-pressure air-cooled generator

Abstract

The invention discloses a novel stator end fixing and ventilating structure suitable for an ultrahigh-pressure air-cooled generator, and belongs to the field of generators. The device comprises a honeycomb-shaped conical ring, a honeycomb-shaped pressing plate and an insulation ventilation pipe, a stator upper layer winding bar and a stator lower layer winding bar are fixed through the honeycomb-shaped conical ring and the honeycomb-shaped pressing plate, and the insulation ventilation pipe is located between the honeycomb-shaped conical ring and the honeycomb-shaped pressing plate and communicated with ventilation holes in the honeycomb-shaped conical ring and the honeycomb-shaped pressing plate to jointly form an end ventilation duct. By increasing the heat dissipation area and shortening the heat conduction distance, the heat dissipation capability of the end part of the generator stator is effectively improved, and the problems of corona prevention and overhigh temperature rise of the end part of the ultrahigh-pressure air-cooled generator stator are solved.

Description

Technical Field

[0001] This invention relates to a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators, belonging to the field of generators. Background Technology

[0002] Currently, most conventional air-cooled generators in China use an insulating bracket and binding ring fixed support structure at the stator end. The stator coil slot outlet is wrapped with high-resistance anti-corona tape and coated with high-resistance anti-corona paint. As the rated voltage of generators continues to increase, the anti-corona problem at the stator end of this structure is becoming increasingly prominent, especially for ultra-high voltage air-cooled generators, such as stator rated voltages of 30kV and above, where the anti-corona problem at the stator end of this structure will be even more severe.

[0003] For water-cooled units, the problem of end corona can be solved by adopting an end-to-end encapsulation structure. However, water-cooled units require a matching water system, and the internal structure of the generator will be more complex, resulting in greater investment in equipment and power plant construction.

[0004] For air-cooled units, if an end-filled glue structure is adopted, although the end-corona prevention problem is solved, the heat at the stator bar ends can only be transferred through thermal radiation and thermal conduction. Due to the lack of an efficient heat dissipation method such as water cooling, the stator end temperature rise will be too high.

[0005] Therefore, there is an urgent need to propose a new stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to disclose a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators. Its function is to solve the problems of stator end corona prevention and excessive stator winding temperature rise in ultra-high voltage air-cooled generators. This is mainly achieved by adopting an integral stator end potting structure to address stator winding corona prevention and fixation issues. By increasing the heat dissipation area of ​​the stator end and shortening the heat conduction distance, its heat dissipation capacity is improved, thus solving the problem of stator end temperature rise. When the unit is running, the cold air at the stator end indirectly cools the stator windings through insulated ventilation pipes, thereby reducing the stator end temperature rise. A brief overview of the invention is provided below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0007] The technical solution of the present invention:

[0008] A novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators includes a honeycomb conical ring, a honeycomb pressure plate, an insulating ventilation pipe, insulating fasteners, and an insulating plug. The honeycomb conical ring surrounds the lower layer of stator bars and is fixed to the stator pressure ring. The honeycomb pressure plate has a segmented structure and is disposed on the top of the upper layer of stator bars, opposite to the honeycomb conical ring. The insulating plug is connected to the inner side of the honeycomb pressure plate, so that the honeycomb conical ring, the honeycomb pressure plate, and the insulating plug together form a structure for accommodating and fixing the stator. The sealed glue-filling cavity is formed at the ends of the upper and lower stator bars. The insulating fasteners pass sequentially through the honeycomb pressure plate, the upper stator bar, the insulating blocking plate, and the lower stator bar, and are fastened to the honeycomb cone ring to form an end fixed support structure. The insulating ventilation pipe is set inside the sealed glue-filling cavity, and its two ends are respectively sealed to the ventilation holes on the honeycomb cone ring and the honeycomb pressure plate, so that the insulating ventilation pipe, the honeycomb cone ring, and the honeycomb pressure plate together form an end ventilation channel that runs through the sealed glue-filling cavity.

[0009] Preferably, the ventilation holes on the honeycomb plate have a diameter larger than the outer diameter of the insulating ventilation pipe.

[0010] Preferably, the gap between the honeycomb pressure plate and the insulating ventilation pipe is filled with impregnated polyester felt.

[0011] Preferably, the insulating fastener is an insulating screw, which passes sequentially through the honeycomb pressure plate, the upper stator bar, the insulating blocking plate, and the lower stator bar. The bottom of the insulating screw is threaded with the honeycomb conical ring, and a disc spring washer is provided between the insulating screw and the honeycomb pressure plate.

[0012] Preferably, the insulating fastener is fitted with an insulating sleeve on its outer side.

[0013] Preferably, the bottom of the insulating fastener is threaded with a honeycomb conical ring, and the top is fitted with a fastening hexagonal nut. The single-ear locking plate is fitted onto the hexagonal nut, and the ear plates on its side are bent at the same time, respectively fastening to the side of the hexagonal nut and the stop pad fixed to the pressure plate, thereby locking the tightened nut.

[0014] Preferably, the honeycomb cone ring is fixed to the stator pressure ring by a supporting sliding pin.

[0015] Preferably, the novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators is applied to ultra-high voltage air-cooled generators with a rated voltage of not less than 30kV.

[0016] The present invention has the following beneficial effects:

[0017] 1. This invention uses a conical ring and a pressure plate to form an integral end-filling space, which fills the air gap between the stator end bars and effectively solves the problem of anti-corona at the stator end of an ultra-high voltage air-cooled generator.

[0018] 2. This invention improves the heat dissipation capacity of the stator end of an ultra-high voltage air-cooled generator by increasing the heat dissipation area at the stator end and shortening the heat conduction distance. It can effectively solve the problem of stator end temperature rise when the ultra-high voltage air-cooled generator adopts an integral end potting structure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators;

[0020] Figure 2 This is a fitting and installation diagram for a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators;

[0021] Figure 3 This is a diagram illustrating the usage status of a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators.

[0022] In the diagram: 1-Honeycomb cone ring; 2-Honeycomb pressure plate; 3-Insulating ventilation pipe; 4-Insulating fastener; 5-Insulating plug; 6-Insulating screw; 7-Hexagonal nut; 8-Disc spring washer; 9-Single-ear locking plate; 10-Stop pad; 11-Insulating sleeve; 12-Upper stator bar; 13-Lower stator bar. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0024] Specific implementation method one: Combining Figures 1-3 This embodiment describes a novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators, comprising a honeycomb cone ring 1, a honeycomb pressure plate 2, an insulating ventilation pipe 3, insulating fasteners 4, and an insulating blocking plate 5.

[0025] The honeycomb conical ring 1 is fixed to the stator pressure ring by a supporting sliding pin and surrounds the periphery of the lower stator bar 13. The honeycomb pressure plate 2 adopts a segmented structure, which facilitates on-site assembly through the bar; it is located on top of the upper stator bar 12. The insulating end plate 5 is connected to the inner end of the honeycomb pressure plate 2. Thus, the honeycomb conical ring 1, the segmented honeycomb pressure plate 2, and the insulating end plate 5 together form a closed potting cavity that encloses the ends of the upper stator bar 12 and the lower stator bar 13. After assembly, insulating potting compound is injected into this cavity, sealing all bar ends into a single unit, effectively eliminating internal air gaps, and thus solving the end corona problem under ultra-high voltage conditions.

[0026] To optimize heat dissipation, the insulating ventilation pipes 3 are evenly distributed within the "rhomboid" cavities formed by the intersection of the upper stator bar 12 and the lower stator bar 13. Ventilation holes corresponding to these "rhomboid" cavities are pre-arranged on both the honeycomb conical ring 1 and the honeycomb pressure plate 2. The two ends of the insulating ventilation pipes 3 are sealed to the ventilation holes on the conical ring 1 and the pressure plate 2, respectively, forming an end ventilation channel that penetrates the closed potting cavity.

[0027] The ventilation holes on the honeycomb plate 2 need to be machined to fit the final actual position of the insulating ventilation pipe 3 during actual assembly, and the hole diameter is slightly larger than the outer diameter of the insulating ventilation pipe 3. This design tolerance ensures assembly feasibility, and the gap between the two is filled by wrapping with impregnated polyester felt, which ensures both airtightness and a certain degree of elasticity and insulation.

[0028] In this embodiment, the insulating fastener 4 includes an insulating screw 6, a hexagonal nut 7, a disc spring washer 8, a single-ear locking plate 9, a stop pad 10, and an insulating sleeve 11.

[0029] The insulating sleeve 11 is fitted over the insulating screw 6 and passes through the honeycomb cone ring 1 to ensure reliable insulation between the metal parts and the grounded cone ring.

[0030] The insulating screw 6 passes sequentially through the honeycomb pressure plate 2, the upper stator bar 12, the insulating blocking plate 5, and the lower stator bar 13. The bottom of the insulating screw 6 is threaded into the honeycomb conical ring 1, and its top threaded end protrudes from the honeycomb pressure plate 2, where a disc spring washer 8 is fitted, and then a hexagonal nut 7 is screwed on. Tightening the hexagonal nut 7 compresses the disc spring washer 8, providing a continuous and stable preload for the entire connection and preventing loosening due to vibration or material shrinkage.

[0031] A more preferred technical solution, providing ultimate anti-loosening protection, includes a mechanical locking mechanism consisting of a single-ear locking plate 9 and a stop pad 10. The stop pad 10 is fixedly mounted on the honeycomb-shaped pressure plate 2. After the hexagonal nut 7 is tightened, the hole in the center of the single-ear locking plate 9 is fitted onto the hexagonal nut 7, and the ear pieces on its side are bent so that part of it is fastened to the side of the hexagonal nut 7, and the other part is fastened to the stop pad 10, thereby reliably locking the nut and eliminating the possibility of its rotation.

[0032] Work process:

[0033] When the generator is running, cooling airflow flows from the outside into the insulated ventilation duct 3. As it flows through the end area, it indirectly carries away the heat generated by the stator bars that are sealed within the potting cavity through the duct wall. This design cleverly embeds a highly efficient indirect cooling air duct within the overall potting and sealing structure, thereby simultaneously solving the two major technical problems that have long been faced by the stator ends of ultra-high voltage air-cooled generators: corona prevention and excessive temperature rise.

[0034] This implementation method is particularly applicable to ultra-high voltage air-cooled generators with rated voltage of 30kV and above.

[0035] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators, characterized in that: The system includes a honeycomb cone ring (1), a honeycomb pressure plate (2), an insulating ventilation pipe (3), insulating fasteners (4), and an insulating blocking plate (5). The honeycomb cone ring (1) surrounds the lower stator bar and is fixed to the stator pressure ring. The honeycomb pressure plate (2) is a segmented structure and is set on the top of the upper stator bar (12), opposite to the honeycomb cone ring (1). The insulating blocking plate (5) is connected to the inner side of the honeycomb pressure plate (2), so that the honeycomb cone ring (1), the honeycomb pressure plate (2), and the insulating blocking plate (5) together form a structure for accommodating and sealing the upper stator bar (12) and the lower stator bar. The sealed potting cavity at the end of the stator bar (13); the insulating fastener (4) passes through the honeycomb plate (2), the upper stator bar (12), the insulating plug (5) and the lower stator bar (13) in sequence, and is fastened to the honeycomb cone ring (1) to form an end fixed support structure; the insulating ventilation pipe (3) is set inside the sealed potting cavity, and its two ends are respectively sealed to the ventilation holes on the honeycomb cone ring (1) and the honeycomb plate (2), so that the insulating ventilation pipe (3), the honeycomb cone ring (1) and the honeycomb plate (2) together constitute the end ventilation channel that runs through the sealed potting cavity.

2. The novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 1, characterized in that: The ventilation holes on the honeycomb plate (2) have a diameter larger than the outer diameter of the insulating ventilation pipe (3).

3. A novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 1, characterized in that: The gap between the honeycomb plate (2) and the insulating ventilation pipe (3) is filled with impregnated polyester felt.

4. A novel stator end fixing and ventilation structure suitable for ultra-high voltage air-cooled generators according to claim 2, characterized in that: The insulating fastener (4) is an insulating screw (6). The insulating screw (6) passes through the honeycomb plate (2), the upper stator bar (12), the insulating block plate (5) and the lower stator bar (13) in sequence. The bottom of the insulating screw (6) is threaded with the honeycomb cone ring (1). A disc spring washer (8) is provided between the insulating screw (6) and the honeycomb plate (2).

5. A novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 1 or 4, characterized in that: An insulating sleeve (11) is fitted on the outside of the insulating fastener (4).

6. A novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 2, characterized in that: The bottom of the insulating fastener (4) is threaded into the honeycomb cone ring (1), and the top is fitted with a tight hexagonal nut (7). The single-ear locking plate (9) is fitted onto the hexagonal nut (7), and the ear plates on its side are bent at the same time, respectively fastening to the side of the hexagonal nut (7) and the stop pad (10) fixed on the pressure plate (2), thereby locking the tightened nut (7).

7. A novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 1, characterized in that: The honeycomb cone ring (1) is fixed to the stator pressure ring by a support sliding pin.

8. A novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators according to claim 1, characterized in that: The novel stator end fixing and ventilation structure for ultra-high voltage air-cooled generators is applied to ultra-high voltage air-cooled generators with a rated voltage of not less than 30kV.

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