Generator stator winding corona discharge positioning system and method

Abstract

This invention discloses a system and method for locating corona discharge in generator stator windings. The system includes a track, two symmetrical supports, and a controller. The supports are I-shaped with adjustable support rod height. A movable crossarm slider is mounted on the crossarm rod, with both ends fixed to the crossarm slider. A track slider is fitted onto the track, enabling circumferential rotation and axial stepping movement. A laser mapping and modeling device and a corona discharge detection device are fixed opposite to each other on the track slider. The method includes: system layout; track center calibration; laser mapping and modeling to establish a cylindrical coordinate system; background noise detection; abnormal discharge detection under rated voltage; and data comparison to screen for true discharge points. This invention achieves blind-spot-free detection throughout the entire stator winding. By establishing a dedicated coordinate system through laser mapping and modeling, combined with ultraviolet and acoustic fingerprint detection methods and background noise comparison, it achieves precise coordinate positioning of corona discharge points, adapting to different generator models and automating operation.

Description

Technical Field

[0001] This invention belongs to the field of power generation technology, specifically relating to a generator stator winding corona discharge positioning system, and also to a generator stator winding corona discharge positioning method. Background Technology

[0002] The insulation structure of the stator winding ends and slots of large generators is very complex. Long-term operation is subject to vibration, mechanical forces, and electromagnetic forces, causing the stator winding insulation material to age and become damaged. Furthermore, oil contamination from the generator accelerates this aging process, leading to uneven electric field distribution in the stator windings and resulting in corona discharge at certain voltages. Without appropriate measures, this can damage the equipment. Currently, there are two methods for detecting corona discharge in generator stator windings: darkroom visual inspection and ultraviolet imaging. Darkroom visual inspection involves creating a darkroom inside the generator stator and visually observing the surface of the stator winding insulation for corona discharge. However, due to the relatively high voltage applied to the stator windings, and for safety reasons, personnel cannot pinpoint the discharge location within the chamber; they must rely on visual observation from the generator ends. This method only allows for a general observation of the approximate location of the corona discharge at the stator ends, and cannot accurately locate it, nor can it detect or precisely locate corona discharge in the slots within the generator chamber. The ultraviolet imaging method measures the corona discharge of the generator stator winding using an ultraviolet imager. However, considering safety, this method can only provide the approximate location of the corona discharge at the end of the generator stator and cannot accurately locate it. Furthermore, it cannot detect or precisely locate the corona discharge in the slots inside the generator stator cavity. Summary of the Invention

[0003] The first objective of this invention is to provide a generator stator winding corona discharge positioning system based on laser scanning mapping modeling, which can perform full-area scanning mapping of the stator winding ends and slots, and mark the coordinates of each position.

[0004] Another objective of this invention is to provide a method for locating corona discharge in generator stator windings based on laser scanning mapping modeling, which can output the precise location of corona discharge at the ends and slots of the generator stator windings.

[0005] The technical solution adopted in this invention is: a generator stator winding corona discharge positioning system, comprising two symmetrically arranged I-shaped support bodies;

[0006] Each support has a crossbar slide block slidably mounted on its crossbar, and the crossbar slide block is equipped with a crossbar drive assembly that drives it to move along the crossbar axis; and each support rod of each support is a height-adjustable structure. A track is fixedly connected between the two crossarm sliders. A track slider is fitted on the outer wall of the track. Inside the track slider is a track drive assembly that drives it to rotate circumferentially and move axially. A laser mapping device and a corona discharge detection device are fixed on the outer surface of the track slider.

[0007] The invention is further characterized by: The track is made up of several short sections joined together end to end.

[0008] It also includes a controller, a laser mapping device, a corona discharge detection device, a crossarm drive assembly, a track drive assembly, and a height adjustment structure for the support rod, all of which are electrically connected to the controller.

[0009] The crossarm drive assembly includes a second rotary motor electrically connected to the controller. The housing of the second rotary motor is fixed inside the crossarm slider. Its output shaft is perpendicular to the crossarm, and a second friction wheel is fixedly sleeved at the end of the output shaft. The second friction wheel is in contact with the outer surface of the crossarm, and the wheel surface of the second friction wheel is parallel to the axis of the crossarm.

[0010] The track drive assembly includes a rotary motor that is electrically connected to the controller. The housing of the rotary motor is fixed inside the track slider. A friction wheel is fixedly sleeved at the end of its output shaft. The friction wheel contacts the outer wall of the track, and the axis of the output shaft of the rotary motor is set at an acute angle to the axis of the track.

[0011] The height adjustment structure of the support rod includes a columnar inner tube and an outer tube, both of which are hollow in structure; The bottom of the outer tube is fixedly connected to the base of the support body, and a through hole with a serrated key is opened in the center of its upper end face; a rotary motor three electrically connected to the controller is fixed at the bottom of the cavity of the outer tube, the output shaft of the rotary motor three is located at the axis of the outer tube, and its output shaft is fixedly connected to a screw through a coupling, and a nut is sleeved on the outer wall of the screw. The top end of the inner tube is fixedly connected to the crossbeam, and the bottom end passes through the perforation of the outer tube and extends into the interior of the outer tube and is coaxial with the outer tube. The outer wall of the inner tube has a groove that matches the serrated key of the perforation. The end of the screw furthest from the rotating motor extends into the inner tube, and the outer circumferential surface of the nut is fixedly connected to the bottom end face of the inner tube.

[0012] The laser mapping device consists of a laser mapping analysis device and a laser mapping probe that are electrically connected to each other, and the corona discharge detection device consists of a corona discharge analysis device and a corona discharge detection probe that are electrically connected to each other; both the laser mapping analysis device and the corona discharge detection device are electrically connected to the controller. Both the laser mapping probe and the corona discharge detection probe are fixed on the outer surface of the track slider, and the two are set 180° away from each other; The corona discharge detection probe includes an ultraviolet camera and an acoustic print imager.

[0013] Another technical solution adopted in this invention is: The method for locating corona discharge in generator stator windings includes the following steps: Step 1. Install the two supports on the excitation side and turbine side of the stator cavity of the generator to be tested, respectively. Horizontally place the track between the two supports and adjust the track to make it coaxial with the central axis of the stator cavity. Step 2. Drive the track slider to move the laser mapping probe from the excitation side of the stator cavity to the turbine side along the track in a rotating and stepping motion. The laser mapping probe performs full-area scanning and mapping of the stator winding end and slot. Based on the mapping data, establish a three-dimensional coordinate system and convert the three-dimensional coordinate system into a cylindrical coordinate system adapted to the cylindrical structure of the stator cavity. Mark the position of each position of the stator winding end and slot with cylindrical coordinates. Step 3. Drive the track slider to move the laser mapping probe and the corona discharge detection probe from the excitation side of the stator cavity to the turbine side along the track in a rotating and stepping motion. Collect the background noise data of corona discharge in the stator cavity through the corona discharge detection probe, and obtain the bar coordinates of the corresponding position of the background noise by combining the mapping coordinate transformation of the laser mapping probe. Step 4. Increase the voltage of the generator stator winding to the rated test voltage, keep the movement parameters of the track slider consistent with those in Step 3, repeat the movement and acquisition operation in Step 3, acquire the high-voltage discharge detection data in the stator cavity through the corona discharge detection probe, and obtain the cylindrical coordinates of the discharge detection position by combining the mapping coordinate transformation of the laser mapping probe. Step 5. Compare the background noise data with the high-voltage discharge detection data and their corresponding bar coordinates, filter out the real corona discharge points, and output the bar coordinates of the real corona discharge points.

[0014] Another feature of the technical solution of the present invention is that: The method for adjusting the track to be coaxial with the central axis of the stator bore in step 1 is as follows: Position the laser mapping probe inside the stator bore and keep it vertical. Control the laser mapping probe to emit three laser beams with the same vertical cross-section. The first laser beam is parallel to the generator platform, and the other two laser beams are symmetrically positioned on either side of the first laser beam, each at a 60° angle to the first laser beam. Detect the distance between the three laser beams and the inner wall of the stator bore. First, adjust the height of the support rod to make the distance values ​​of the lasers on both sides equal. Then, adjust the horizontal position of the track on the support body to make the distance value of the first laser beam consistent with the distance values ​​of the lasers on both sides. Simultaneously, fine-tune the height of the support rod to maintain the distance values ​​of the lasers on both sides equal until the distance values ​​of the three laser beams are completely identical. At this point, the track is coaxial with the central axis of the stator bore.

[0015] Data in a cylindrical coordinate system is represented as ( r t , θ t , zt ),

[0016] in,( X 0, Y 0, Z 0) is the origin of the three-dimensional coordinate system, ( X t , Y t , Z t )for t Three-dimensional coordinate data at any given time; The corona discharge detection probe includes an ultraviolet camera and an acoustic print imager. Both the background noise data and the high-voltage discharge detection data include photon count and sound pressure level. The selection criteria for real corona discharge points are that the coordinates of the high-voltage discharge detection position and the background noise detection position are different, or the coordinates are the same and the photon number and sound pressure value of the high-voltage discharge are greater than those of the background noise. The number of photons was detected by an ultraviolet camera, and the sound pressure level was detected by an acoustic imaging device.

[0017] The beneficial effects of this invention are: The positioning system of this invention features an adjustable support height and an adjustable track horizontal position. The track slider can simultaneously rotate circumferentially and move axially, achieving 360° full-area coverage detection within the stator bore without blind spots. It acquires spatial structural data of the stator windings through laser scanning mapping and modeling, converting the three-dimensional coordinates into a cylindrical coordinate system adapted to the cylindrical structure of the stator bore, and uniquely labeling each position with coordinates, providing a precise coordinate reference for locating the discharge point. The system employs a dual-method detection approach using an ultraviolet camera and an acoustic imaging device, simultaneously acquiring the light and sound signals of corona discharge. Compared to a single detection method, this approach covers multiple physical characteristics of corona discharge, reducing the probability of missed or false detections.

[0018] The positioning method of this invention performs dual comparison of coordinates and discharge quantity by detecting background noise under no high voltage conditions and discharge detection under high voltage tests. This effectively eliminates interference signals such as ambient stray light and mechanical vibration, ensuring that the final output discharge point is the real corona discharge point generated by the insulation defect of the stator winding, and can output the accurate cylindrical coordinates of the discharge point. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the positioning system of the present invention; Figure 2 A schematic diagram of the control connection of the positioning system of the present invention; Figure 3 for Figure 1 Schematic diagram of the installation structure of the middle track slider; Figure 4 for Figure 1 Schematic diagram of the installation structure of the crossarm slider; Figure 5 for Figure 1 A schematic diagram of the cross-sectional structure of the central support rod; Figure 6 This is a schematic diagram showing the distribution of the three laser beams emitted by the laser mapping probe of the present invention; Figure 7 This is a schematic diagram illustrating the establishment of the three-dimensional coordinate system of this invention; Figure 8 This is a schematic diagram illustrating the establishment of the cylindrical coordinate system of this invention.

[0020] In the diagram: 1. Track, 11. Track slider, 12. Rotary motor 1, 13. Friction wheel 1; 2. Support body, 21. Crossbeam, 22. Support rod, 221. Inner tube, 222. Outer tube, 223. Rotary motor three, 224. Coupling, 225. Screw, 226. Nut, 23. Base, 24. Crossbeam slider, 25. Rotary motor two, 26. Friction wheel two. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 The generator stator winding corona discharge positioning system provided in this embodiment, such as Figure 1 and 2 As shown, it includes a track 1, two symmetrically arranged supports 2, and a controller.

[0023] The support body 2 is an I-shaped structure, including a crossbeam 21, a support rod 22, and a base 23. The crossbeam 21 and the base 23 are parallel and horizontally arranged, and the support rod 22 is vertically fixed between the crossbeam 21 and the base 23.

[0024] Each crossarm 21 is equipped with a crossarm slider 24, such as Figure 4 The crossarm slider 24 is located outside the crossarm 21, through which the crossarm 21 passes. A rotary motor 25 is mounted on the crossarm slider 24, with its housing fixed inside. The output shaft of the rotary motor 25 is perpendicular to the crossarm 21. A friction wheel 26 is fixedly fitted at the end of the rotary motor 25. The outer circumferential surface of the friction wheel 26 is in close contact with the outer surface of the crossarm 21, and the wheel surface of the friction wheel 26 is parallel to the axis of the crossarm 21. The rotary motor 25 is communicatively connected to a controller. In use, after the controller starts the rotary motor 25, its output shaft rotates, causing the friction wheel 26 to rotate, which in turn drives the crossarm slider 24 to move linearly along the axis of the crossarm 21.

[0025] The track 1 is horizontally positioned, with its two ends fixed to two crossarm sliders 24. A track slider 11 is fitted onto the outer wall of the track 1, and each track slider 11 has a through threaded hole or through-hole at its center. A rotary motor 12 is also installed inside the track slider 11. Figure 3 As shown, the housing of the rotary motor 12 is fixed inside the track slider 11. A friction wheel 13 is fitted onto the end of its output shaft. The center hole of the friction wheel 13 is fixedly connected to the outer wall of the output shaft, and the outer circumferential surface of the friction wheel 13 is in close contact with the track 1. The angle between the axis of the output shaft of the rotary motor 12 and the axis of the track 1 is acute. By adjusting this acute angle, the circumferential rotation speed of the track slider 11 and its stepping speed along the track 1 can be adjusted. A laser mapping device and a corona discharge detection device are fixed to the outer surface of the track slider 11.

[0026] Rotary motor 12 is electrically connected to a controller, which controls the speed and direction of rotation of rotary motor 12. In operation, the controller drives the output shaft of rotary motor 12 to rotate, which in turn drives friction wheel 13 to rotate. Friction wheel 13 moves simultaneously along the axial and circumferential directions of track 1, thereby causing track slider 11 and the laser mapping device and corona discharge detection device mounted on it to slide horizontally and rotate circumferentially simultaneously. This achieves a rotary stepping movement of the laser mapping probe and the corona discharge detection probe on track 1. Furthermore, by controlling the rotation direction of the rotary motor, the laser mapping probe and the corona discharge detection probe can move in opposite directions.

[0027] Support rod 22 is a height-adjustable structure, such as Figure 5As shown, the system includes an inner tube 221, an outer tube 222, a rotary motor 223, a coupling 224, a screw 225, and a nut 226. The outer tube 222 is a hollow cylindrical shape, with its lower end fixed to the upper surface of the base 23. A through hole is formed at the center of its upper end, with a serrated key structure at the edge of the through hole. The housing of the rotary motor 223 is fixed to the bottom of the cavity of the outer tube 222. Its output shaft is located on the axis of the outer tube 222, and the end of the output shaft is connected to the coupling 224. A screw 225 is fixed to the end of the coupling 224 away from the rotary motor 223. The screw 225 is located on the axis of the outer tube 222, and a nut 226 is fitted onto the outer wall of the screw 225. The inner tube 221 is a hollow cylindrical shape with a diameter smaller than that of the outer tube. Its top end is fixedly connected to the crossbeam 21, and its bottom end extends into the outer tube 222 through the through hole on its upper end, and is coaxial with the outer tube 222. The outer wall of the inner tube 221 has a groove structure along the axial direction that matches the serrated key on the perforation edge, preventing circumferential rotation of the inner tube 221 through the keyway engagement. The end of the screw 225 furthest from the rotary motor 223 extends into the inner tube 221, and the outer circumferential surface of the nut 226 is fixed to the bottom end face of the inner tube 221. The rotary motor 223 is communicatively connected to the controller. In use, the controller starts the rotary motor 223, causing its output shaft to rotate, which in turn rotates the screw 225. The nut 226 moves axially along the screw 225, causing the inner tube 221 to slide up and down.

[0028] Example 2 Based on Example 1, this example provides a generator stator winding corona discharge positioning system: The track 1 is a cylindrical rod, and its material is not limited to aluminum alloy, cast iron, or wood. To facilitate transportation and rapid on-site assembly, the track 1 adopts a multi-section split structure and is spliced ​​together by threads. It is divided into 7 standard sections, each 2m long. Each track 1 section has an external thread at one end and an internal thread at the other end. Adjacent track 1 sections are connected by the engagement of the internal and external threads to achieve smooth splicing of the track 1. In actual use, according to the axial length of the stator cavity of the generator under test, the corresponding number of standard track 1 sections are selected for splicing, so that the total length of the spliced ​​track 1 is greater than or equal to the axial length of the stator cavity of the generator under test. This ensures that the track slider 11 can drive the laser mapping device and the corona discharge detection device to complete the full-area movement detection of the stator cavity from the excitation side to the turbine side. The two ends of the spliced ​​track 1 are still fixed to the two crossarm sliders 24 respectively.

[0029] Example 3 Based on Example 2, this example provides a generator stator winding corona discharge positioning system: The laser mapping device consists of a laser mapping analysis device and a laser mapping probe. The laser mapping probe is electrically connected to the laser mapping analysis device, and the spatial mapping data acquired by the laser mapping probe is transmitted to the laser mapping analysis device for processing. The corona discharge detection device consists of a corona discharge analysis device and a corona discharge detection probe. The corona discharge detection probe is electrically connected to the corona discharge detection device, and the discharge signal data acquired by the corona discharge detection probe is transmitted to the corona discharge analysis device for processing. Both the laser mapping analysis device and the corona discharge detection device are electrically connected to the controller.

[0030] Both the laser mapping probe and the corona discharge detection probe are fixed on the outer surface of the track slider 11. Their detection axes are collinear and extend in opposite directions with an included angle of 180°, so that the detection position of the corona discharge detection probe corresponds to the mapping position of the laser mapping probe in the circumferential direction at 180°.

[0031] Example 4 Based on Example 3, this example provides a generator stator winding corona discharge positioning system. The specific parameters of the laser mapping device are as follows: The ranging range is 0.3–150 m; the ranging accuracy is ±1–3 mm; the repeatability is ±0.1 mm; the spatial accuracy is ±2–5 mm; the horizontal scanning angle is 0°–360° continuous; the vertical scanning angle is -30°–+130°; the angular resolution is 0.001°–0.01° (adjustable); the minimum step angle is ≤30 seconds; the scanning point frequency is 300,000–2,000,000 points / second; the horizontal rotation speed is adjustable (e.g., 3–60 rpm); the laser wavelength is 905 nm or 1550 nm; the laser class is Class 1 (eye-safe); the ranging method is phase-based or pulse-based; the rotation is driven by a stepper or servo motor, and the fixed tilt angle α is adjustable; the power supply is DC12–24V or AC220V; the output is three-dimensional spatial coordinates (X, Y, Z).

[0032] Example 5 Based on Example 4, this example provides a generator stator winding corona discharge location system. The corona discharge detection probe is a combined ultraviolet and acoustic fingerprint detection structure, including an ultraviolet camera and an acoustic fingerprint imager, which can simultaneously acquire the optical and acoustic signals of corona discharge, avoiding missed detections and false detections by a single detection method. Specific parameters are as follows: Parameters of the ultraviolet camera: ultraviolet detection band 240–280 nm (solar-blind ultraviolet band); detection sensitivity ≥1×10 -18 W / cm 2 The system can detect discharge types including corona discharge, arc discharge, surface discharge, and tip discharge; the discharge intensity display is based on photon counting, with a counting range of 0-32600. The ultraviolet camera moves synchronously with the track slider 11 to collect and transmit ultraviolet photon signals in real time.

[0033] The parameters of the acoustic print imager are as follows: the core acoustic component is a microphone array with ≥48 array elements, and it is a MEMS digital microphone; the operating frequency band is 20Hz~70kHz; the detection sensitivity is ≤-40dBV / Pa; the spatial positioning accuracy is ≤3cm; the effective detection distance is 0.5m~20m; the acoustic print imager starts and stops synchronously with the ultraviolet camera, collects the sound pressure and frequency signals of corona discharge in real time, and transmits them synchronously with the detection data of the ultraviolet camera to the corona discharge analysis device.

[0034] The detection thresholds of both the ultraviolet camera and the acoustic print imager can be set by the controller. When the detected signal exceeds the set threshold, the corona discharge detection device automatically triggers the image storage function to save the image of the discharge point location. The image data, detection signal data, and location coordinate data are synchronously fed back to the controller.

[0035] Example 6 Based on Example 5, this example provides a generator stator winding corona discharge positioning system. The rotational speed of the rotary motor 12 is set to 3-60 rpm, and the angle between the output shaft axis of the rotary motor 12 and the axis of the track 1 is an acute angle α, with an adjustment range of 5°-15°. The track 1 is a cylindrical rod with a diameter of R, ranging from 2-3 cm. Based on the above parameters, the circumferential rotational speed and axial stepping speed along the track 1 driven by the track slider 11 are calculated: circumferential rotational speed V 旋转 =2πRr1 (where r1 is the actual rotational speed of the rotary motor-12); Axial stepping speed V 旋转 =2πRr1 / cosα. The rotation direction of the rotary motor 12 can be switched by the controller to realize the forward and reverse movement of the track slider 11, which facilitates position callback and repeated detection during the detection process.

[0036] Based on the above positioning system, the present invention also provides a method for locating corona discharge of generator stator windings, which is implemented according to the following steps: Step 1: Complete the layout and calibration of the above positioning system in the generator area; 1.1 Install two supports 2 on the outer sides of the two ends of the stator bore of the generator to be tested. One support rod 22 is close to the casing on the excitation side of the generator stator bore, and the other is close to the casing on the turbine side of the generator stator bore. Select the track 1 according to the length of the generator stator, and ensure that the length of the track 1 is greater than or equal to the length of the generator, and that the track 1 is coaxial with the generator stator bore.

[0037] 1.2 Adjust the height of the support body 2 and the horizontal position of the track 1 by means of the controller so that the track 1 is located at the central axis of the generator stator bore; First, adjust the track slider 11 into the generator stator bore, and keep the laser mapping probe vertical; then, control the laser mapping probe to emit three coplanar laser beams via the controller, such as... Figure 6 As shown, lasers a, b, and c are located on the same vertical section. Laser a is perpendicular to the laser mapping probe, i.e., parallel to the generator platform. Lasers b and c are symmetrically positioned on either side of laser a, with each laser b and c forming a 60° angle with laser a. The distance values ​​from the three laser beams to the inner wall of the stator cavity are detected and obtained using a laser mapping device, denoted as f(a), f(b), and f(c). If f(b) > f(c), the height of the support rod 22 in the support body is adjusted upwards until f(b) = f(c). If f(b) < f(c), the height of the support rod 22 in the support body 2 is adjusted downwards until f(b) = f(c). If f(b) = f(c), the support body is maintained. The height of rod 22 remains unchanged; after the above height adjustment is completed, if f(a) < f(b), adjust the horizontal position of track 1 on crossarm 21 so that track 1 moves in the opposite direction of laser a emission until f(a) = f(b). During the movement of track 1, the height of support rod 22 is adjusted synchronously to keep f(b) = f(c); if f(a) > f(b), adjust the horizontal position of track 1 on crossarm 21 so that track 1 moves in the direction of laser a emission until f(a) = f(b). During the movement of track 1, the height of support rod 22 is adjusted synchronously to keep f(b) = f(c); when f(a) = f(b) = f(c), track (1) is located at the central axis of generator stator bore.

[0038] Step 2: Use a laser scanning and mapping device to perform full-area scanning and mapping of the stator winding ends and slots. Based on the laser mapping data, establish a cylindrical coordinate system in the stator bore and mark the coordinates of each position of the winding ends and slots. 2.1 Set the rotational speed of the rotating motor 12. Establish a three-dimensional coordinate system f1(X, Y, Z) with the top of the generator excitation side track as the origin, the direction from the excitation side to the turbine side as the Z-axis, the direction to the right along the crossbeam 21 of the support body 2 facing the Z-axis as the X-axis, and the support direction along the support rod 22 of the support body as the Y-axis. Figure 7 and 8 As shown; the laser scanning and mapping device is started and the scanning and mapping function is activated. The controller drives the track slider 11 to move the laser scanning and mapping device from the top of the excitation side track to the turbine side along track 1 in a rotating and stepping motion, completing the full-area mapping and modeling of the generator stator winding ends and slots, and collecting and obtaining the specific three-dimensional coordinates (X, Y, X) of each part of the stator winding. t Y t Z t ).

[0039] 2.2 Since the generator stator winding has a cylindrical structure, a cylindrical coordinate system can more directly reflect the specific location of corona discharge. Therefore, it is necessary to convert the three-dimensional coordinate system into a cylindrical coordinate system adapted to the stator bore structure. Based on the three-dimensional coordinate data obtained from the laser scanning mapping, the top of the generator excitation side track is taken as the origin of the cylindrical coordinate system, the direction from the excitation side to the turbine side is taken as the Z-axis, the direction facing the Z-axis and along the support rod 22 of the support body 2 is taken as the r-axis, and the angle between the support rod 22 and the r-axis formed by counterclockwise rotation along the r-axis is taken as θ. A cylindrical coordinate system f2(r, θ, z) is established. The obtained three-dimensional coordinates (X) t Y t Z t Convert the data to bar coordinates using a conversion formula (r). t θ t , z t The specific conversion formula is as follows:

[0040] The origin of the three-dimensional coordinate system is (X0, Y0, Z0). Data is processed and calculated using a laser mapping and analysis device to ultimately obtain and complete the cylindrical coordinates (r) of each position at the end and slot of the generator stator winding. t θ t , z t ).

[0041] Step 3: Drive the laser mapping probe and the corona discharge detection probe from the excitation side of the stator cavity to the turbine side by the track slider 11 and rotate and move along the track 1 to complete the measurement and acquisition of background noise data of corona discharge in the stator cavity and the corresponding position coordinates. The corona discharge detection device includes an ultraviolet camera and an acoustic print imager. The ultraviolet camera is used to detect the number of photons generated by the corona discharge to determine the presence and intensity of the corona discharge, and the initial number of photons for the corona discharge is preset to n1. The acoustic print imager is used to detect the sound pressure and frequency of the corona discharge to determine the presence and intensity of the corona discharge, and the initial sound pressure for the corona discharge is preset to p1.

[0042] First, move the track slider 11 to the end of the generator excitation side track, i.e., the origin of the cylindrical coordinate system, and adjust the corona discharge detection probe to align it with the r-axis direction of the cylindrical coordinate system. The controller then controls the rotary motor 12 to run at speed r1, causing the track slider 11 to rotate and step along the track axis on track 1, simultaneously measuring and collecting the background noise (n) of the corona discharge inside the stator bore. k p kThe coordinates of the laser mapping probe and the corona discharge detection probe are shown below. Since the laser mapping probe and the corona discharge detection probe are installed 180° opposite each other, and the corona discharge detection position forms a 180° angle with the mapping position of the laser mapping probe, the mapping coordinates of the laser mapping probe are converted to the coordinates of the corona discharge detection position (r). k θ k +180°, z k ).

[0043] After the track slider 11 moves from the excitation side of track 1 to the turbine side to complete the full-stroke detection, m background discharge points are finally obtained, and the coordinate position (r) of each background discharge point is recorded. k θ k +180°, z k ) and background noise data (n k p k ), where k = 1, 2, 3, ..., m.

[0044] Step 4: Increase the voltage of the generator stator winding to the rated test voltage, keep the movement parameters of the track slider 11 consistent with those in Step 3, repeat the movement and acquisition operation in Step 3, collect the high-voltage discharge detection data in the stator cavity through the corona discharge detection probe, and obtain the cylindrical coordinates of the discharge detection position by combining the mapping coordinate transformation of the laser mapping probe. First, move the track slider 11 to the end of the generator excitation side track, i.e., the origin of the cylindrical coordinate system, and adjust the corona discharge detection probe to align it with the r-axis direction of the cylindrical coordinate system. After boosting the generator stator winding voltage to the rated test voltage, the controller controls the rotating motor 12 to run at a speed of r1, driving the track slider 11 to rotate and step along the track axis on track 1. The corona discharge detection probe simultaneously performs full-stroke detection. When the number of photons detected by the ultraviolet camera is greater than the preset initial photon number n1, or the sound pressure detected by the acoustic imager is greater than the preset initial sound pressure p1, the corona discharge detection device immediately takes a picture of the location and stores it, and simultaneously records the discharge measurement value (photon number n) at that location. q Sound pressure p q Because the laser mapping probe and the corona discharge detection probe are installed 180° opposite each other, and the corona discharge detection position forms a 180° angle with the mapping position of the laser mapping probe, the real-time mapping coordinates of the laser mapping probe are converted into cylindrical coordinates of the corona discharge position (r). q θ q +180°, z qDuring the detection process, photos of the corona discharge points are transmitted to the corona discharge analysis device, and the location information of the discharge points is transmitted to the laser mapping analysis device for storage. After the track slider 11 moves from the excitation side of track 1 to the turbine side to complete the full-stroke detection, s high-voltage discharge detection points are finally obtained, and the corresponding cylindrical coordinate position (r) of each detection point is recorded. q θ q +180°, z q ) and discharge measurement value (n q p q ), where q = 1, 2, 3, ..., s.

[0045] Step 5: Compare the background noise data with the high-voltage discharge detection data and their corresponding bar graph coordinates, filter out the real corona discharge points, and output the bar graph coordinates of the real corona discharge points.

[0046] The coordinates (r) of the background discharge point obtained in step 3 k θ k +180°, z k ), background noise data (n k p k The coordinates (r) of the high-voltage discharge detection point obtained in step 4 are compared with those of the points obtained in step 4. q θ q +180°, z q ), discharge measurement value (n) q p q A comparative analysis was conducted; firstly, the coordinate positions were compared, and the two sets of coordinates were matched one by one. The t detection points in the high-voltage discharge detection points whose coordinate positions differed from the background discharge points were selected, and their corresponding columnar coordinates (r) were recorded. a θ a +180°, z a (a=1, 2, 3, ..., t), and discharge measurement value (n) a p a 1) Take photos of the discharge points; then compare the discharge quantity of background discharge points and high-voltage discharge detection points with the same coordinate positions, and select u detection points with the same coordinate positions but whose high-voltage discharge photon count and sound pressure value are both greater than the background noise, i.e., satisfying n q >n k And p q >p k The detection points are recorded, and their corresponding cylindrical coordinates (r) are recorded. b θ b +180°, z b (b=1, 2, 3, ..., u) and discharge measurement values ​​(n) b p b ), and a photo of the discharge point.

[0047] After double screening, a total of t+u true corona discharge points were determined at the ends and slots of the generator stator winding. Finally, the columnar coordinates, discharge measurement values ​​and corresponding discharge point photos of all true corona discharge points were output, realizing the accurate positioning of the corona discharge points of the generator stator winding.

Claims

1. A generator stator winding corona discharge positioning system, characterized in that, It includes two symmetrically arranged I-shaped supports (2); Each support body (2) has a crossbar slider (24) slidably mounted on its crossbar (21). The crossbar slider (24) is equipped with a crossbar drive assembly that drives it to move axially along the crossbar (21). Furthermore, each support body (2) has a support rod (22) with an adjustable height. A track (1) is fixedly connected between the two crossarm sliders (24). A track slider (11) is sleeved on the outer wall of the track (1). The track slider (11) is equipped with a track drive assembly that drives it to rotate circumferentially and move axially along the track (1). A laser mapping device and a corona discharge detection device are fixed on the outer surface of the track slider (11).

2. The generator stator winding corona discharge positioning system according to claim 1, characterized in that, The track (1) is made up of several short sections joined together end to end.

3. The generator stator winding corona discharge positioning system according to claim 1, characterized in that, It also includes a controller, a laser mapping device, a corona discharge detection device, a crossarm drive assembly, a track drive assembly, and a height adjustment structure for the support rod (22), all of which are electrically connected to the controller.

4. The generator stator winding corona discharge positioning system according to claim 3, characterized in that, The crossarm drive assembly includes a second rotary motor (25) electrically connected to the controller. The housing of the second rotary motor (25) is fixed inside the crossarm slider (24). Its output shaft is perpendicular to the crossarm (21), and a second friction wheel (26) is fixedly sleeved at the end of the output shaft. The second friction wheel (26) contacts the outer surface of the crossarm (21), and the wheel surface of the second friction wheel (26) is parallel to the axis of the crossarm (21).

5. The generator stator winding corona discharge positioning system according to claim 3, characterized in that, The track drive assembly includes a rotary motor (12) electrically connected to the controller. The housing of the rotary motor (12) is fixed inside the track slider (11). A friction wheel (13) is fixedly sleeved at the end of its output shaft. The friction wheel (13) contacts the outer wall of the track (1), and the axis of the output shaft of the rotary motor (12) is set at an acute angle to the axis of the track (1).

6. The generator stator winding corona discharge positioning system according to claim 3, characterized in that, The height adjustment structure of the support rod (22) includes a columnar inner tube (221) and an outer tube (222), both of which are hollow inside. The bottom of the outer tube (222) is fixedly connected to the base (23) of the support body (2), and a through hole with a serrated key is opened at the center of its upper end face; a rotary motor three (223) electrically connected to the controller is fixed at the bottom of the cavity of the outer tube (222), the output shaft of the rotary motor three (223) is located at the axis of the outer tube (222), and its output shaft is fixedly connected to a screw (225) through a coupling (224), and a nut (226) is sleeved on the outer wall of the screw (225); The top end of the inner tube (221) is fixedly connected to the crossbar (21), and the bottom end passes through the perforation of the outer tube (222) and extends into the interior of the outer tube (222) and is coaxial with the outer tube (222). The outer wall of the inner tube (221) is provided with a groove that matches the perforation sawtooth key. The end of the screw (225) away from the rotary motor (223) extends into the inner tube (221), and the outer circumferential surface of the nut (226) is fixedly connected to the bottom end of the inner tube (221).

7. The generator stator winding corona discharge positioning system according to claim 4, characterized in that, The laser mapping device consists of a laser mapping analysis device and a laser mapping probe that are electrically connected to each other, and the corona discharge detection device consists of a corona discharge analysis device and a corona discharge detection probe that are electrically connected to each other; both the laser mapping analysis device and the corona discharge detection device are electrically connected to the controller. Both the laser mapping probe and the corona discharge detection probe are fixed on the outer surface of the track slider (11), and the two are set 180° apart. The corona discharge detection probe includes an ultraviolet camera and an acoustic print imager.

8. A method for locating corona discharge in generator stator windings, characterized in that, Includes the following steps: Step 1. Install the two supports (2) on the excitation side and the turbine side of the stator cavity of the generator to be tested, respectively. Horizontally place the track (1) between the two supports (2) and adjust the track (1) to make it coaxial with the central axis of the stator cavity. Step 2. Drive the track slider (11) to drive the laser mapping probe to rotate and move along the track (1) from the excitation side of the stator cavity to the turbine side. Scan and map the end of the stator winding and the slot through the laser mapping probe. Establish a three-dimensional coordinate system based on the mapping data, and convert the three-dimensional coordinate system into a cylindrical coordinate system adapted to the cylindrical structure of the stator cavity. Mark the position of each position of the end of the stator winding and the slot with cylindrical coordinates. Step 3. Drive the track slider (11) to drive the laser mapping probe and the corona discharge detection probe to rotate and move along the track (1) from the excitation side of the stator cavity to the turbine side. Collect the background noise data of corona discharge in the stator cavity through the corona discharge detection probe, and obtain the bar coordinates of the corresponding position of the background noise by combining the mapping coordinate transformation of the laser mapping probe. Step 4. Increase the voltage of the generator stator winding to the rated test voltage, keep the movement parameters of the track slider (11) consistent with those in step 3, repeat the movement and acquisition operation in step 3, collect the high voltage discharge detection data in the stator cavity through the corona discharge detection probe, and obtain the columnar coordinates of the discharge detection position by combining the mapping coordinate transformation of the laser mapping probe. Step 5. Compare the background noise data with the high-voltage discharge detection data and their corresponding bar coordinates, filter out the real corona discharge points, and output the bar coordinates of the real corona discharge points.

9. The generator stator winding corona discharge positioning method according to claim 8, characterized in that, The method for adjusting the track (1) in step 1 to make it coaxial with the central axis of the stator cavity is as follows: the laser mapping probe is adjusted into the stator cavity and kept vertical. The laser mapping probe is controlled to emit three laser beams with the same vertical cross section. The first laser beam is parallel to the generator platform, and the other two laser beams are symmetrically arranged on both sides of the first laser beam and the angle between them is 60°. The distance measurement value of the three laser beams to the inner wall of the stator cavity is detected. First, the height of the support rod (22) is adjusted to make the distance measurement value of the laser beams on both sides equal. Then, the horizontal position of the track (1) on the support body (2) is adjusted to make the distance measurement value of the first laser beam consistent with the distance measurement value of the laser beams on both sides. At the same time, the height of the support rod (22) is finely adjusted to keep the distance measurement value of the laser beams on both sides equal until the distance measurement value of the three laser beams is exactly the same. At this time, the track (1) is coaxial with the central axis of the stator cavity.

10. The generator stator winding corona discharge positioning method according to claim 8, characterized in that, The data in the cylindrical coordinate system is represented as ( r t , θ t , z t ), in,( X 0, Y 0, Z 0) is the origin of the three-dimensional coordinate system, ( X t , Y t , Z t )for t Three-dimensional coordinate data at any given time; The corona discharge detection probe includes an ultraviolet camera and an acoustic print imager. Both the background noise data and the high-voltage discharge detection data include the number of photons and the sound pressure level. The screening criteria for the actual corona discharge point are that the coordinates of the high-voltage discharge detection position and the background noise detection position are different, or the coordinates are the same and the photon count and sound pressure value of the high-voltage discharge are greater than those of the background noise. The number of photons was obtained by an ultraviolet camera, and the sound pressure level was obtained by an acoustic imaging device.

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