Stator end part structural member wind path of million-level steam turbine generator axial ventilation system

Abstract

The invention relates to the field of steam turbine generators, and discloses a stator end part structural member wind path of a million-level steam turbine generator axial ventilation system, and the end part wind path adopts axial ventilation of heat dissipation ventilation holes and ventilation channel steel and radial heat dissipation air duct ventilation, so that the magnetic shielding heat dissipation of the end part is enhanced, and accidents caused by overheating of the end part are avoided; and the device is very suitable for being used on a million-level steam turbine generator. The wind path comprises magnetic shielding groups of stepped structures, ventilation channel steel and the like which are respectively arranged at the steam end and the excitation end of the generator. The stepped magnetic shielding groups at the steam end and the excitation end are respectively composed of five layers, cross section air holes and ventilation channel steel of each odd number of layers of magnetic shielding punching sheets are regularly assembled so as to facilitate axial ventilation, meanwhile, heat dissipation air channels are symmetrically arranged among the first, second, third and fourth layers of magnetic shielding and the fifth layer of magnetic shielding and the magnetic shielding pressing plate in the radial direction, the cooling area of the magnetic shielding at the end is increased, and the heat dissipation efficiency is improved. The heat dissipation of the end part structural member is enhanced, and the operation stability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbine generators, and in particular to an air path of a stator end structural component of an axial ventilation system of a million-class steam turbine generator. Background Art

[0002] The stator core and magnetic shield of the million-class steam turbine generator are the parts that generate significant heat, causing a large temperature rise, and even becoming a factor in limiting the output. The million-class steam turbine generator has a large coil pitch and a large number of coils per phase, resulting in a long winding end and a large inclination angle of the slot.

[0003] The line load is large, the magnetic density is high, and the end leakage is large, forming a large rotating leakage magnetic field. The end leakage flux always passes along the path with the smallest magnetic resistance. Therefore, the coupling of the leakage flux is mainly concentrated at the magnetic shield at the end of the stator. The leakage flux causes eddy current loss in the magnetic shield, resulting in increased additional loss of the end magnetic shield and increased temperature. Therefore, a special cooling method must be adopted at the end of the million-class steam turbine generator, otherwise the end magnetic shield will overheat and cause an accident. At present, the cooling technology of the end magnetic shield is one of the key technologies in the development of million-class steam turbine generators. Summary of the invention

[0004] The purpose of the present invention is to disclose a stator end structural component wind path suitable for the axial ventilation system of a million-class steam turbine generator, which has the characteristics of simple structure, good heat dissipation effect, easy installation, good insulation effect, etc., and can better solve the heating problem of the stator end of the million-class steam turbine generator.

[0005] The technical solution of the present invention is: a steam-end magnetic shielding group with a special heat dissipation structure on the steam end of a million-class steam turbine generator, and an excitation-end magnetic shielding group with a special heat dissipation structure on the excitation-end of a million-class steam turbine generator, wherein the steam-end magnetic shielding group is composed of 5 layers of magnetic shielding with a step structure, which are axially arranged with rectangular ventilation slots and linear ventilation slots, the rectangular ventilation slots are axially matched with the magnetic shielding heat dissipation ventilation holes, and the linear ventilation slots are radially matched with the magnetic shielding heat dissipation ventilation holes, forming axial and radial heat dissipation ducts of the steam-end magnetic shielding group with a step structure, and the excitation-end magnetic shielding group is composed of 5 layers of magnetic shielding with a special structure, which are axially arranged with rectangular ventilation slots and linear ventilation slots, the rectangular ventilation slots are axially matched with the magnetic shielding heat dissipation ventilation holes, and the linear ventilation slots are radially matched with the magnetic shielding heat dissipation ventilation holes, forming axial and radial heat dissipation ducts of the excitation-end magnetic shielding group with a step structure.

[0006] As a preferred embodiment, the steam-end magnetic shielding group of the million-class steam turbine generator has 5 layers of magnetic shielding in a stepped structure, a heat dissipation duct is radially arranged between the first steam-end magnetic shielding and the second steam-end magnetic shielding, a heat dissipation duct is radially arranged between the third steam-end magnetic shielding and the fourth steam-end magnetic shielding, and a heat dissipation duct is radially arranged between the fifth steam-end magnetic shielding and the steam-end magnetic shielding pressure plate. Four rows of heat dissipation vents are provided between the inner and outer diameters of each layer of magnetic shielding, rectangular ventilation slots are radially arranged at intervals between the heat dissipation vents of the first steam-end magnetic shielding, and linear ventilation slots are arranged at the remaining positions, rectangular ventilation slots are arranged at the two rows of heat dissipation vents near the outer diameter of the third steam-end magnetic shielding, and linear ventilation slots are arranged at the remaining positions, ventilation slots are arranged at intervals between one row of heat dissipation vents near the outer diameter of the fifth steam-end magnetic shielding, and linear ventilation slots are arranged at some positions.

[0007] As a preferred embodiment, the magnetic shielding group of the excitation end of the million-class steam turbine generator has a 5-layer magnetic shielding of a stepped structure, a radial heat dissipation duct is arranged between the first excitation end magnetic shielding and the second excitation end magnetic shielding, a radial heat dissipation duct is arranged between the third excitation end magnetic shielding and the fourth excitation end magnetic shielding, and a radial heat dissipation duct is arranged between the excitation end magnetic shielding pressure plates of the fifth excitation end magnetic shielding. Four rows of heat dissipation vents are arranged between the inner and outer diameters of each layer of magnetic shielding, a rectangular ventilation channel steel is arranged outside each heat dissipation venting hole of the first excitation end magnetic shielding and the third excitation end magnetic shielding, and linear ventilation channel steel is arranged at the remaining positions, and a row of heat dissipation venting holes of the fifth excitation end magnetic shielding close to the outer diameter is arranged with a rectangular ventilation channel steel, and linear ventilation channel steel is arranged at some positions.

[0008] The beneficial effects of the present invention are:

[0009] (1) The steam end and excitation end magnetic shielding groups of the present invention are both stepped, which enlarges the inner diameter of the end magnetic shielding, so that the leakage magnetic flux is dispersed on each step segment according to the magnetic resistance, reducing the leakage magnetic flux entering the stator core and magnetic shielding from the axial direction, and preventing the magnetic flux from being excessively concentrated on the edge magnetic shielding to form local high temperature points, thereby providing ventilation and cooling capabilities for the end magnetic shielding.

[0010] (2) The steam-end and excitation-end magnetic shielding groups of the present invention are radially provided with heat dissipation ducts between layers, thereby increasing the heat dissipation area of ​​the magnetic shielding and allowing the heat generated by the eddy current loss caused by the end leakage magnetic field in the magnetic shielding and the heat generated by the hot air flowing through the axial heat dissipation ventilation holes inside the magnetic shielding to be fully transferred to the ducts. At the same time, the radial ducts that penetrate the ducts can take air from the cooler or from the air gap, thereby increasing the amount of cold air and enhancing the heat dissipation effect.

[0011] (3) The first, third and fifth axial magnetic shielding layers at the steam end of the present invention are an arrangement and combination of heat dissipation vents and ventilation channel steels, so that the air volume taken from the cooler and the air gap is more evenly transmitted to the heat dissipation vents of each layer of the magnetic shielding, avoiding excessive wind resistance. The axial air intake of the steam end magnetic shielding is more even, so that the heat of the magnetic shielding and the iron core is more evenly transmitted to the cold air, thereby enhancing the overall heat dissipation effect and avoiding accidents caused by overheating of the stator iron core and the magnetic shielding.

[0012] (4) The heat dissipation ventilation holes of the first, third and fifth axial magnetic shielding layers at the excitation end of the present invention are all matched with ventilation channel steel, so that the cold air entering from the steam end absorbs the heat of the stator core and the magnetic shielding and then flows out from the axial ventilation holes at the excitation end, preventing the hot air from intersecting with the cold air. The high pressure of the cold air causes the hot air to flow back to the excitation end, thereby avoiding the heating of the stator core caused by the hot air backflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] Figure 2 This is a schematic diagram of the assembly of the first-layer steam end magnetic shield and ventilation channel steel;

[0015] Figure 3 This is a schematic diagram of the third-layer steam end magnetic shield and ventilation channel steel assembly;

[0016] Figure 4 This is a schematic diagram of the fifth-layer steam end magnetic shield and ventilation channel steel assembly;

[0017] Figure 5 This is a schematic diagram of the assembly of the first-layer excitation end magnetic shield and ventilation channel steel;

[0018] Figure 6 This is a schematic diagram of the assembly of the third-layer excitation end magnetic shield and ventilation channel steel;

[0019] Figure 7 This is a schematic diagram of the fifth-layer excitation end magnetic shield and ventilation channel steel assembly;

[0020] Description of component numbers in the accompanying drawings:

[0021] 1. Stepped steam end magnetic shielding group; 2. Stepped excitation end magnetic shielding group; 3. First steam end magnetic shielding; 4. Second steam end magnetic shielding; 5. Third steam end magnetic shielding; 6. Fourth steam end magnetic shielding; 7. Fifth steam end magnetic shielding; 8. First excitation end magnetic shielding; 9. Second excitation end magnetic shielding; 10. Third excitation end magnetic shielding; 11. Fourth excitation end magnetic shielding; 12. Fifth excitation end magnetic shielding; 13. Rectangular ventilation channel steel; 14. Linear ventilation channel steel; 15. Steam end magnetic shielding pressure plate; 16.

[0022] Excitation end magnetic shielding pressure plate. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and beneficial effects of the present invention clearer, further explanation will be given below in conjunction with the accompanying drawings and specific embodiments, but each embodiment does not constitute a limitation of the present invention. The specific embodiments described in the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] like Figure 1 As shown, a stator end structural member wind path of the axial ventilation system of a million-class steam turbine generator comprises a steam end magnetic shielding group 1 of a stepped structure arranged on the steam end of the million-class steam turbine generator, and an excitation end magnetic shielding group 2 of a stepped structure arranged on the excitation end of the million-class steam turbine generator. The steam end magnetic shielding is composed of five layers of stepped magnetic shielding, a radial heat dissipation air duct is arranged between the first layer of steam end magnetic shielding 3 and the second layer of steam end magnetic shielding 4, a radial heat dissipation air duct is arranged between the third layer of steam end magnetic shielding 5 and the fourth layer of steam end magnetic shielding 6, and a radial heat dissipation air duct is arranged between the fifth layer of steam end magnetic shielding 7 and the steam end magnetic shielding pressing plate 15. The excitation end magnetic shielding is also composed of five layers of stepped magnetic shielding, and the radial heat dissipation air duct is arranged in the same way as the steam end. The radial heat dissipation air duct increases the heat dissipation area of ​​the magnetic shielding, and the radial air duct that penetrates can take air from the cooler or the air gap, thereby increasing the air volume of the cold air and enhancing the heat dissipation effect. Four rows of heat dissipation ventilation holes are arranged between the inner and outer diameters of each layer of magnetic shielding; rectangular ventilation slots 13 are arranged radially at intervals on the heat dissipation ventilation holes of the first layer of steam-end magnetic shielding 3, and linear ventilation slots 14 are arranged at other positions; rectangular ventilation slots 13 are arranged at two rows of heat dissipation ventilation holes near the outer diameter of the third layer of steam-end magnetic shielding 5, and linear ventilation slots 14 are arranged at other positions; rectangular ventilation slots 13 are arranged at intervals on one row of heat dissipation ventilation holes near the outer diameter of the fifth layer of steam-end magnetic shielding 7, and linear ventilation slots 14 are arranged at some positions.

[0025] like Figure 2 , 3 As shown in Figure 4, 4 rows of heat dissipation vents are provided between the inner and outer diameters of each layer of magnetic shielding. The heat dissipation vents of the first layer of steam end magnetic shielding 3 are radially spaced with rectangular vent steel slots 13, and the remaining positions are provided with linear vent steel slots 14. The 2 rows of heat dissipation vents near the outer diameter of the third layer of steam end magnetic shielding 5 are provided with rectangular vent steel slots 13, and the remaining positions are provided with linear vent steel slots 14. The 1 row of heat dissipation vents near the outer diameter of the fifth layer of steam end magnetic shielding 7 is spaced with vent steel slots 13, and some positions are provided with linear vent steel slots 14. The air volume taken from the cooler and the air gap is more evenly conducted to the heat dissipation vents of each layer of magnetic shielding, and the axial air intake of the stepped structure steam end magnetic shielding group 1 is more even, so that the heat of the magnetic shielding and the stator core is more evenly conducted to the cold air, thereby enhancing the overall heat dissipation effect and avoiding accidents caused by overheating of the stator core and magnetic shielding.

[0026] like Figure 5 , 6 As shown in Figure 7, four rows of heat dissipation ventilation holes are opened between the inner and outer diameters of each layer of magnetic shielding. A rectangular ventilation slot steel 13 is arranged outside each heat dissipation ventilation hole of the first layer of excitation end magnetic shielding 8 and the third layer of excitation end magnetic shielding 10, and linear ventilation slot steel 14 is arranged at the remaining positions. A row of heat dissipation ventilation holes near the outer diameter of the fifth layer of excitation end magnetic shielding 12 is arranged with a rectangular ventilation slot steel 13, and linear ventilation slot steel 14 is arranged at some positions. The cold air entering from the steam end absorbs the heat of the stator core and the magnetic shielding and then flows out from the axial ventilation holes of the excitation end to prevent the hot air from intersecting with the cold air. The cold air pressure is high, which causes the hot air flowing to the excitation end to flow back.

[0027] Finally, the protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope and spirit of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.

Claims

1. A stator end structural member wind path of the axial ventilation system of a million-class steam turbine generator, characterized in that: The steam end magnetic shielding group (1) of the stepped structure is composed of a first layer of steam end magnetic shielding (3), a second layer of steam end magnetic shielding (4), a third layer of steam end magnetic shielding (5), a fourth layer of steam end magnetic shielding (6), a fifth layer of steam end magnetic shielding (7), a rectangular ventilation channel steel (13) and a linear ventilation channel steel (14) which are axially arranged; the rectangular ventilation channel steel (13) is axially matched with the magnetic shielding heat dissipation ventilation holes, and the linear ventilation channel steel (14) is radially matched with the magnetic shielding heat dissipation ventilation holes, so as to form the axial and radial heat dissipation air ducts of the steam end magnetic shielding group (1) of the stepped structure; The ladder-structured excitation end magnetic shielding group (2) is composed of a first layer of excitation end magnetic shielding (8), a second layer of excitation end magnetic shielding (9), a third layer of excitation end magnetic shielding (10), a fourth layer of excitation end magnetic shielding (11), a fifth layer of excitation end magnetic shielding (12), rectangular ventilation slot steels (13) and linear ventilation slot steels (14) which are axially arranged; the rectangular ventilation slot steels (13) are axially matched with the magnetic shielding heat dissipation ventilation holes, and the linear ventilation slot steels (14) are radially matched with the magnetic shielding heat dissipation ventilation holes, so as to form axial and radial heat dissipation air ducts of the ladder-structured excitation end magnetic shielding group (2).

2. The stator end structural member wind path of the axial ventilation system of a million-class steam turbine generator according to claim 1 is characterized in that: The steam end magnetic shielding group (1) of the stepped structure comprises a heat dissipation duct radially arranged between the first steam end magnetic shielding (3) and the second steam end magnetic shielding (4), a heat dissipation duct radially arranged between the third steam end magnetic shielding (5) and the fourth steam end magnetic shielding (6), and a heat dissipation duct radially arranged between the fifth steam end magnetic shielding (7) and the steam end magnetic shielding pressure plate (15). Heat dissipation ventilation holes are provided between the inner and outer diameters of each layer of magnetic shielding. Rectangular ventilation slots (13) are radially arranged at intervals between the heat dissipation ventilation holes of the first steam end magnetic shielding (3), and linear ventilation slots (14) are arranged at the remaining positions. Two rows of heat dissipation ventilation holes of the third steam end magnetic shielding (5) are arranged near the outer diameter, and linear ventilation slots (14) are arranged at the remaining positions. One row of heat dissipation ventilation holes of the fifth steam end magnetic shielding (7) is arranged at intervals, and linear ventilation slots (14) are arranged at some positions.

3. The stator end structural member wind path of the axial ventilation system of a million-class steam turbine generator according to claim 1 is characterized in that: The step-structured excitation end magnetic shielding group (2) comprises a first excitation end magnetic shielding (8) and a second excitation end magnetic shielding (9) with a radial heat dissipation duct, a third excitation end magnetic shielding (10) and a fourth excitation end magnetic shielding (11) with a radial heat dissipation duct, and a fifth excitation end magnetic shielding (12) and an excitation end magnetic shielding pressure plate (16) with a radial heat dissipation duct. Heat dissipation vents are provided between the inner and outer diameters of each magnetic shielding layer. A rectangular ventilation slot steel (13) is provided outside each heat dissipation venting hole of the first excitation end magnetic shielding (8) and the third excitation end magnetic shielding (10), and linear ventilation slot steels (14) are provided at other locations. A row of heat dissipation venting holes of the fifth excitation end magnetic shielding (17) near the outer diameter is provided with a rectangular ventilation slot steel (13), and linear ventilation slot steels (14) are provided at other locations.

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