A tool and method for detecting the depth of wire under insulation of a stator winding of a turbogenerator

Abstract

The present application relates to a kind of generator stator winding depth detection technical field, specifically related to a kind of steam turbine generator stator winding depth detection tool and method.It includes telescopic piece, the upper end of telescopic piece is rotatably connected with line pressing wheel, line pressing wheel outer edge forms line pressing tread, telescopic piece lower end is fixed with car frame, multiple walking wheels are rotatably arranged in the lower end of car frame, multiple walking wheels are linear array in the direction of car frame travel, line pressing wheel can roll in the core groove of stator core, the middle of multiple walking wheels is outwardly convex and forms protruding portion, protruding portion outer edge forms walking tread, the protruding portion of multiple walking wheels can roll in the core groove of stator core, the outer edge surface of the walking wheel portion on the both sides of protruding portion can be matched with the inner edge surface of stator core.This tool can continuously roll in the core groove of stator core, realize fast scanning, replace traditional point-by-point manual measurement, greatly shorten detection time, improve work efficiency.

Description

Technical Field

[0001] This invention relates to the field of generator stator winding depth detection technology, specifically to a tool and method for detecting the stator winding depth of a steam turbine generator. Background Technology

[0002] When replacing stator coils (commonly known as coil bars) on-site in a steam turbine generator, the new coil bars need to be installed into the stator core slots. After confirming that the coil is in place, the straight section is fixed with a process slot wedge, the ends of the coil bars are bound, and after baking and curing, the working slot wedge is driven in. An electrical withstand voltage test is then performed to check the insulation. Due to the possibility of overlapping at the bottom of some coil bar slots or between layers of padding (especially interlayer padding strips, which are approximately 7.6mm thick), the coil bar may not be deep enough to install, preventing the slot wedge from being installed. In this case, the already cured end bindings need to be removed and the coil re-installed, resulting in waste of labor, spare parts, and materials, and delays in the maintenance schedule. Previous methods for determining the coil depth suffer from problems such as reliance on experience, time-consuming and labor-intensive inspections, small inspection coverage, and low accuracy.

[0003] Currently, there are several ways to determine the depth of stator bars in large steam turbines: 1. Visually observe and feel to determine the installation position of the bars in the slot; 2. After using temporary supports to tighten the bars, use a depth gauge to measure the depth of the bars; 3. After each bar is installed, select a few sections and use a depth measuring mold in conjunction with a feeler gauge to determine the depth of the bars.

[0004] Visually and tactilely observing the depth of the lower wire rod relies on the individual experience of the installer, resulting in low accuracy and consistency. Using temporary supports to tighten the lower wire rod and then measuring the depth with a depth gauge requires multiple people to work together to press it down, which is inefficient and relies on sampling, making it difficult to cover the entire length of the wire rod groove, thus limiting accuracy.

[0005] In the prior art, patent document CN111220055 B discloses a method for measuring the depth of the stator slots in a steam turbine generator. This method involves taking several measurement points on the same stator after the stator bar is in place, and using a measuring mold and feeler gauge to determine the depth. This is also a sampling inspection, and its accuracy is limited. Furthermore, when using this method to check the depth of the stator bar at the top of the stator circumference, a significant auxiliary force is required to press the stator bar down. Therefore, this method is mainly suitable for stator slotting on a rolling platform within a generator manufacturing plant. Summary of the Invention

[0006] The main objective of this invention is to provide a tool and method for detecting the depth of the stator winding of a steam turbine generator, thereby solving the problems of relying on personal experience, having a small sampling coverage, and limited detection accuracy when using conventional equipment and methods for inspection and measurement.

[0007] To achieve the above objectives, the technical solution provided by this invention is as follows: A tool for detecting the unwinding depth of a steam turbine generator stator winding includes a telescopic component. A pressure wheel is rotatably connected to the upper end of the telescopic component, and a pressure tread is formed on the outer edge of the pressure wheel. A frame is fixed to the lower end of the telescopic component, and multiple traveling wheels are rotatably arranged on the lower end of the frame. The multiple traveling wheels are linearly arranged in the traveling direction of the frame. The pressure wheel can roll in the core slot of the stator core. The middle of the traveling wheel protrudes outward to form a protrusion, and the outer edge of the protrusion forms a traveling tread. The protrusion of the traveling wheel can roll in the core slot of the stator core. The outer edge surfaces of the traveling wheel portions on both sides of the protrusion can match and fit with the inner edge surfaces of the stator core.

[0008] Specifically, the upper end of the telescopic component is fixed with a bracket, the axle of the pressure wheel is rotatably connected to the bracket through a first bearing, and the axle of the walking wheel is rotatably connected to the vehicle frame through a second bearing.

[0009] Specifically, the vertical line connecting the axis of the pressing wheel and the axis of one of the traveling wheels is perpendicular to the line connecting the axes of the two traveling wheels.

[0010] Specifically, the pressure roller and the traveling roller are made of nylon or epoxy glass fiber material, and the edges of the pressure roller tread are processed with rounded chamfers.

[0011] Specifically, the telescopic component includes an outer tube and an inner tube. The outer edge of the inner tube has a scale in the axial direction. The lower part of the inner tube is inserted into the outer tube. The upper end of the inner tube is located outside the outer tube. The upper end of the outer tube is provided with a locking unit for locking the inner tube. The pressure wheel is rotatably located at the upper end of the inner tube. The frame is fixed at the lower end of the outer tube.

[0012] Specifically, the outer tube has an external thread machined on its upper outer side, a lock nut is fitted on the upper end of the outer tube, the inner tube passes through the lock nut, a tapered internal thread is machined inside the lock nut, the tapered internal thread is threaded to the external thread, and multiple vertical slits are evenly distributed around the upper circumference of the outer tube.

[0013] Specifically, the frame and the outer tubing are fixedly connected by diagonal supports, and a traction ring is fixed on the diagonal supports.

[0014] Specifically, the bracket is connected to the upper end of the telescopic component via a contact pressure sensor.

[0015] Specifically, the inner and outer tubes are connected by a thrust spring, and the outer tube is equipped with a displacement sensor capable of measuring the displacement of the inner tube.

[0016] Specifically, the pressure roller and the inclined support adopt a hollow design.

[0017] A method for using a tool for detecting the depth of the stator winding of a steam turbine generator includes the following steps: S1. Calculate the height difference L (i.e., the depth of the wire) between the top surface of the inner wire bar and the top of the core tooth after the wire is laid, based on the thickness of the core slot, outer wire bar, inner wire bar, interlayer spacer and liner of the generator stator core. S2. Calculate the distance H from the top of the pressure tread to the bottom of the travel tread based on the inner diameter of the generator stator core and the depth of the lower wire. S3. Adjust the length of the telescopic component so that the distance between the top point of the pressure tread and the bottom point of the walking tread is equal to H; S4. After the outer wire bar, inner wire bar, interlayer spacer strip and liner are installed, the pressure wheel is embedded into the iron core groove where the outer wire bar, inner wire bar, interlayer spacer strip and liner are located, and the pressure tread is pressed against the side of the inner wire bar facing the stator iron core axis. The protrusion in the middle of the traveling wheel is embedded into the iron core groove in the stator iron core space opposite to the pressure wheel. At this time, the outer edge surface of the traveling wheel part on both sides of the protrusion matches and fits the inner edge surface of the stator iron core. S5. Move this tool from one end of the stator core to the other. If the protrusions of the pressure wheel and the traveling wheel can pass smoothly through the core slot during the movement of this tool, it indicates that the depth of the wire in the core slot is normal. Otherwise, check whether the position or setting of the outer wire bar, inner wire bar, interlayer spacer strip and liner at the blockage point is abnormal.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This tool can continuously roll within the stator core slots, enabling rapid scanning and replacing traditional point-by-point manual measurement. This significantly shortens inspection time and improves work efficiency. The pressure wheel and traveling wheel are made of epoxy fiberglass or nylon material, ensuring measurement accuracy while preventing damage to the insulation layer of the inner bars and the stator core.

[0019] 2. The use of sliding connection between the inner and outer pipe fittings ensures that the length of this tool is adjustable and suitable for steam turbine generators of different capacities; by setting a lock nut and opening multiple slits at the upper end of the outer pipe fitting, reliable locking of the inner pipe fitting is achieved; the outer surface of the inner pipe fitting is marked with graduations, which can be used to set the total length of this tool.

[0020] 3. A raised section is formed in the middle of the traveling wheel. The outer edge of the raised section has a height difference with the outer edges of the two sides of the traveling wheel. During operation, the raised section is located in the iron core slot, and the outer edge surface of the traveling wheel on both sides of the raised section matches and fits with the inner edge surface of the stator iron core, ensuring that the traveling wheel will not come out of the iron core slot and will not contact the slot wedge of the iron core slot. The edge of the pressure tread is machined with a rounded chamfer, which can ensure that the pressure tread surface of the pressure wheel is in full contact with the end face of the inner wire bar facing the axis of the stator iron core, preventing the corrugated plate on the side of some iron core slots from contacting the pressure tread surface when it is higher than the inner wire bar and affecting the measurement accuracy.

[0021] 4. By setting up a contact pressure sensor or a displacement sensor, the accuracy of the detection results can be further improved. Attached Figure Description

[0022] Figure 1 This is the front view of this tool.

[0023] Figure 2 This is a side view of the tool.

[0024] Figure 3 for Figure 2 A magnified view of region I in the middle.

[0025] Figure 4 This is a schematic diagram of the upper end of the outer pipe fitting.

[0026] Figure 5 for Figure 4 Sectional view along line AA.

[0027] Figure 6 This is a front view when using this tool to detect the depth of the offline line.

[0028] Figure 7 This is a side view of the process of using this tool to detect the depth of the line.

[0029] Figure 8 This is a schematic diagram illustrating the movement direction when using this tool to detect the depth of the bottom line.

[0030] Figure 9 This is a schematic diagram showing the depth of other iron core slots after the tool has been rotated.

[0031] The components in the attached diagram are named as follows: 1. Pressing wheel, 2. Traveling wheel, 3. Inner tube, 4. Outer tube, 5. Lock nut, 6. External thread, 7. Tapered internal thread, 8. Slit, 9. Knurling, 10. Scale, 11. Pressing tread, 12. Traveling tread, 13. First bearing, 14. Second bearing, 15. Diagonal support, 16. Traction ring, 17. Outer bar, 18. Inner bar, 19. Interlayer spacer, 20. Stator core, 21. Core slot, 22. Frame, 23. Bracket. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Example 1: As Figures 1-9 As shown, a tool for detecting the depth of stator winding of a steam turbine generator includes a telescopic component, with a pressure wheel 1 rotatably connected to the upper end of the telescopic component, and a pressure tread surface 11 formed on the outer edge of the pressure wheel 1.

[0034] The lower end of the telescopic component is fixed with a frame 22, and multiple traveling wheels 2 are rotatably arranged at the lower end of the frame 22. The multiple traveling wheels 2 are linearly arranged in the traveling direction of the frame 22.

[0035] Furthermore, a bracket 23 is fixed to the upper end of the telescopic component, the axle of the pressure wheel 1 is rotatably connected to the bracket 23 through the first bearing 13, and the axle of the walking wheel 2 is rotatably connected to the frame 22 through the second bearing 14.

[0036] The line connecting the axis of the pressing wheel 1 and the axis of one of the traveling wheels 2 is perpendicular to the line connecting the axes of the two traveling wheels. After installing this tool, it can prevent the tool from accidentally tipping over due to an unstable center of gravity.

[0037] The pressure roller 1 can roll in the core slot 21 of the stator core 20. The travel roller 2 has a raised part in the middle, and the outer edge of the raised part forms a travel tread 12. The raised part of the travel roller 2 can roll in the core slot 21 of the stator core 20. The outer edge surface of the travel roller 2 on both sides of the raised part can match and fit with the inner edge surface of the stator core 20.

[0038] The pressure roller 1 and the traveling roller 2 are made of nylon or epoxy fiberglass. Therefore, damage to the insulation layer of the inner wire bar 18 can be avoided during the wire depth detection process.

[0039] The edge of the pressure tread 11 is machined with a rounded chamfer to ensure that the pressure tread 11 of the pressure roller 1 is in full contact with the end face of the inner wire bar 18 facing the axis of the stator core 20, and to prevent the corrugated plate on the side of some core slots 21 from contacting the pressure tread 11 when it is higher than the inner wire bar 18 and affecting the measurement accuracy.

[0040] The expansion joint includes an outer tube 4 and an inner tube 3. The outer edge of the inner tube 3 is provided with a scale 10 in the axial direction. By providing the scale 10 on the outer side of the inner tube 3, it is convenient to adjust the overall length of the outer tube 4 and the inner tube 3.

[0041] The lower part of the inner tube 3 is inserted into the outer tube 4, the upper end of the inner tube 3 is located outside the outer tube 4, the upper end of the outer tube 4 is provided with a locking unit to lock the inner tube 3, the pressure wheel 1 is rotatably set on the upper end of the inner tube 3, and the frame 22 is fixed on the lower end of the outer tube 4.

[0042] The outer tube 4 has an external thread 6 machined on its upper outer side. A lock nut 5 is fitted onto the upper end of the outer tube 4. The outer edge of the lock nut 5 is knurled 9. The inner tube 3 passes through the lock nut 5. The lock nut 5 has a tapered internal thread 7 machined inside, which is threaded to the external thread 6. Multiple vertical slits 8 are evenly distributed around the upper circumference of the outer tube 4. By rotating the lock nut 5, as the lock nut 5 moves downwards on the outside of the outer tube 4, the lock nut 5 can press against the upper end of the outer tube 4 and lock the inner tube 3 tightly inside.

[0043] The frame 22 and the outer tube 4 are fixedly connected by a diagonal support 15, on which a traction ring 16 is fixed. By setting the diagonal support 15, the structural strength of the connection between the outer tube 4 and the frame 22 can be improved. By setting the traction ring 16, it is convenient to pull the tool in the stator core 20.

[0044] During operation, the height difference L (i.e., the threading depth) between the top surface of the inner rod 18 and the top of the core tooth is calculated based on the thickness of the core slot 21, outer rod 17, inner rod 18, interlayer spacer 19 and padding material of the generator stator core 20.

[0045] The distance H from the top of the pressure tread 11 to the bottom of the travel tread 12 is calculated based on the inner diameter of the generator stator core 20 and the depth of the lower wire.

[0046] Loosen the lock nut 5, and then adjust the overall length of the outer tube 4 and the inner tube 3 so that the distance between the top of the pressure tread 11 and the bottom of the walking tread 12 is equal to H. Then rotate the lock nut 5 to lock the inner tube 3 into the outer tube 4.

[0047] After the outer wire bar 17, inner wire bar 18, interlayer spacer 19, and liner are installed, the pressure wheel 1 is embedded into the core groove 21 containing the outer wire bar 17, inner wire bar 18, interlayer spacer 19, and liner, with the pressure tread surface 11 pressing against the inner wire bar 18 facing the axis of the stator core 20. The protrusion in the middle of the traveling wheel 2 is then embedded into the core groove 21 in the space of the stator core 20, opposite to the pressure wheel 1. At this time, the outer edge surfaces of the traveling wheel 2 portions on both sides of the protrusion match and fit against the inner edge surfaces of the stator core 20.

[0048] Move this tool from one end of the stator core 20 to the other. If the protrusions of the pressure wheel 1 and the traveling wheel 2 can pass smoothly through the core groove 21, it indicates that the wire depth of the core groove 21 is normal. Otherwise, check whether the position or setting of the outer wire bar 17, inner wire bar 18, interlayer spacer 19 and liner at the blockage point is abnormal.

[0049] Example 2: Based on Example 1, the bracket 23 is connected to the upper end of the telescopic component via a contact pressure sensor.

[0050] A contact pressure sensor is installed between the upper end of the telescopic component and the bracket 23, and the contact pressure sensor is electrically connected to the display screen via a controller. During the movement of this tool from one end of the stator core 20 to the other, the change in pressure value displayed on the screen determines whether the depth of the core groove 21 is normal. If the change in pressure value between the bracket 23 and the upper end of the telescopic component is within the set range, the depth of the core groove 21 is normal. Conversely, if the change is outside the set range, the depth of the core groove 21 is abnormal. When the display screen shows that the maximum pressure between the bracket 23 and the upper end of the telescopic component reaches the limit, the tool stops moving; at this point, the position corresponding to the pressure roller 1 is a blockage point.

[0051] Example 3: The inner tube 3 and the outer tube 4 are connected by a thrust spring, and the outer tube 4 is equipped with a displacement sensor that can measure the displacement of the inner tube 3.

[0052] In this embodiment, the displacement sensor is electrically connected to the display screen via a controller. During the detection of the lower wire depth, the inner tube 3 is not locked. As the tool moves within the stator core 20, the change in the displacement of the inner tube 3 displayed on the screen determines whether the lower wire depth of the core slot 21 is normal. If the change in the displacement of the inner tube 3 is within a set range, the lower wire depth of the core slot 21 is normal. Conversely, if the change is outside the set range, the lower wire depth of the core slot 21 is abnormal. When the displacement value of the inner tube 3 displayed on the screen reaches the compression limit, the tool stops moving; at this point, the position corresponding to the pressure wheel 1 is a blockage point.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tool for detecting the depth of stator winding unwinding of a steam turbine generator, comprising a telescopic component, characterized in that, The upper end of the telescopic component is rotatably connected to a pressure wheel (1), and the outer edge of the pressure wheel (1) forms a pressure tread (11). The lower end of the telescopic component is fixed with a frame (22), and the lower end of the frame (22) is rotatably equipped with multiple traveling wheels (2). The multiple traveling wheels (2) are arranged linearly in the traveling direction of the frame (22). The pressure wheel (1) can roll in the core slot (21) of the stator core (20). The middle of the traveling wheel (2) protrudes outward to form a protrusion, and the outer edge of the protrusion forms a traveling tread (12). The protrusion of the traveling wheel (2) can roll in the core slot (21) of the stator core (20). The outer edge of the traveling wheel (2) on both sides of the protrusion can match and fit with the inner edge of the stator core (20).

2. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 1, characterized in that, The upper end of the telescopic component is fixed with a bracket (23), the axle of the pressure wheel (1) is rotatably connected to the bracket (23) through the first bearing (13), and the axle of the walking wheel (2) is rotatably connected to the frame (22) through the second bearing (14).

3. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 1, characterized in that, The line connecting the axis of the pressing wheel (1) and the axis of one of the traveling wheels (2) is perpendicular to the line connecting the axes of the two traveling wheels.

4. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 1, characterized in that, The pressing wheel (1) and the traveling wheel (2) are made of nylon or epoxy glass fiber material, and the edge of the pressing tread (11) is processed with a rounded chamfer.

5. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 1, characterized in that, The telescopic component includes an outer tube (4) and an inner tube (3). The inner tube (3) has a scale (10) on its outer edge in the axial direction. The lower part of the inner tube (3) is inserted into the outer tube (4). The upper end of the inner tube (3) is located outside the outer tube (4). The upper end of the outer tube (4) is provided with a locking unit for locking the inner tube (3). The pressure wheel (1) is rotatably set on the upper end of the inner tube (3). The frame (22) is fixed on the lower end of the outer tube (4).

6. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 5, characterized in that, The outer tube (4) has an external thread (6) machined on the outer side of its upper end. A lock nut (5) is fitted on the upper end of the outer tube (4). The inner tube (3) passes through the lock nut (5). A tapered internal thread (7) is machined inside the lock nut (5). The tapered internal thread (7) is threaded to the external thread (6). Multiple vertical slits (8) are evenly distributed around the upper circumference of the outer tube (4).

7. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 5, characterized in that, The frame (22) and the outer tube (4) are fixedly connected by a diagonal support (15). A traction ring (16) is fixed on the diagonal support (15). The pressure wheel (1) and the diagonal support (15) adopt a hollow design.

8. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 2, characterized in that, The bracket (23) is connected to the upper end of the telescopic component via a contact pressure sensor.

9. The tool for detecting the unwinding depth of a steam turbine generator stator winding according to claim 5, characterized in that, The inner tube (3) and the outer tube (4) are connected by a thrust spring, and the outer tube (4) is equipped with a displacement sensor that can measure the displacement of the inner tube (3).

10. A method for using a tool for detecting the unwinding depth of a steam turbine generator stator winding as described in claim 1, characterized in that, Includes the following steps: S1. Calculate the height difference L (i.e., the depth of the wire) between the top surface of the inner wire bar (18) and the top of the core tooth after the wire is laid, based on the thickness of the core slot (21), outer wire bar (17), inner wire bar (18), interlayer spacer (19) and padding material of the generator stator core (20). S2. Calculate the distance H from the top of the pressure tread (11) to the bottom of the travel tread (12) based on the inner diameter of the generator stator core (20) and the depth of the lower wire; S3. Adjust the length of the telescopic component so that the distance between the top of the pressure tread (11) and the bottom of the walking tread (12) is equal to H; S4. After the outer wire bar (17), inner wire bar (18), interlayer spacer (19) and padding are installed, the pressure wheel (1) is embedded into the iron core groove (21) where the outer wire bar (17), inner wire bar (18), interlayer spacer (19) and padding are located, and the pressure tread (11) is pressed against the side of the inner wire bar (18) facing the axis of the stator iron core (20). The protrusion in the middle of the traveling wheel (2) is embedded into the iron core groove (21) in the space of the stator iron core (20) opposite to the pressure wheel (1). At this time, the outer edge surface of the traveling wheel (2) on both sides of the protrusion matches and fits the inner edge surface of the stator iron core (20). S5. Move this tool from one end of the stator core (20) to the other end. If the protrusions of the pressure wheel (1) and the traveling wheel (2) can pass smoothly through the core groove (21) during the movement of this tool, it means that the depth of the core groove (21) is normal. Otherwise, check whether the position or setting of the outer wire bar (17), inner wire bar (18), interlayer pad (19) and padding at the blockage point is abnormal.

Images