Fault detection system and method for stator core

Abstract

The invention relates to a fault detection system and method for a stator core. The system comprises a plurality of layers of punching sheets, the inner sides of the punching sheets are provided with tooth parts, and the plurality of layers of punching sheets are laminated to form a stator core; the local excitation iron core is in contact with tooth parts on the two sides of a fault tooth part of the punching sheet, and the fault tooth part is not in contact with the local excitation iron core; the ring current eliminating iron core and the local excitation iron core are located at different layers of punching sheets, and the ring current eliminating iron core is in contact with tooth parts on the two sides of the corresponding tooth part of the punching sheet where the ring current eliminating iron core is located and does not make contact with the corresponding tooth part of the punching sheet where the ring current eliminating iron core is located; and the corresponding tooth parts and the fault tooth parts are the same row of tooth parts along the axial direction of the stator core. By using the system, the induced circulation generated when the fault tooth part of the stator iron core is excited by using the local excitation iron core can be eliminated.

Description

Technical Field

[0001] This application relates to the field of electrical maintenance technology, and in particular to a fault detection system and method for stator cores. Background Technology

[0002] The stator core is an important component of a large generator. When the insulation between the stator core laminations is damaged, it can cause significant losses. Therefore, insulation diagnosis of the stator core is an important task in generator maintenance.

[0003] Traditional stator core fault diagnosis methods commonly used include the iron loss method and the electromagnetic fault detection method (ELCID). While the iron loss method can directly reflect the temperature rise at the fault point, it requires an MVA-level power supply, which is difficult to implement in power plants and can easily damage the generator. ELCID, on the other hand, only requires a KVA-level power supply and can be implemented in power plants, but because it provides quadrature-axis current results, it cannot directly display the temperature rise, thus requiring an iron loss test. However, in practice, the quadrature-axis current often exceeds the standard while the iron loss test passes, easily leading to misdiagnosis of the fault point. To safely and quickly identify whether a fault truly exists in the core, a C-type core can be used to locally excite the fault point, causing precise heating. Observation using an infrared imager allows for the location and assessment of the fault severity.

[0004] However, when traditional C-type iron cores determine whether a fault exists, they use a single local excitation core for excitation, which leads to an imbalance of magnetic flux in each branch of the stator winding. Consequently, local excitation will cause induced circulating currents between the in-phase double Y-shaped windings in the slot, making excitation difficult. Summary of the Invention

[0005] Therefore, it is necessary to provide a fault detection system and method for stator cores that can eliminate the induced circulating current generated when a single local excitation core is excited, in order to address the above-mentioned technical problems.

[0006] In a first aspect, this application provides a fault detection system for a stator core. The stator core includes multiple layers of laminations arranged sequentially along its axial direction, with teeth provided on the inner side of the laminations. The fault detection system includes:

[0007] The local excitation core is in contact with the two sides of the faulty tooth of the lamination, while the faulty tooth is not in contact with the local excitation core.

[0008] The circulating current eliminator core and the local excitation core are located at laminations in different layers. The circulating current eliminator core contacts the two sides of the corresponding teeth of the lamination, but does not contact the corresponding teeth of the lamination. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core.

[0009] In one embodiment, the preset number of contact teeth when the local excitation core contacts the two sides of the faulty tooth is 4.

[0010] In one embodiment, the longitudinal section of the local excitation core and / or the circulating current elimination core has a first side and a second side that are opposite and arc-shaped, the openings of the first side and the second side are aligned, and the central angle corresponding to the first side is the same as the central angle corresponding to the second side.

[0011] The longitudinal section also has a first straight side connecting one end of the first side and one end of the second side, and a second straight side connecting the other end of the first side and the other end of the second side;

[0012] The contour formed by the first side, the second side, the first straight side, and the second straight side extends along the thickness direction to form a locally excitation core and / or a circulating current elimination core with thickness.

[0013] A first recessed structure is provided on the surface area of ​​the local excitation core near and relative to the faulty tooth;

[0014] The circulating current elimination core has a first recessed structure on the surface area near and relative to the corresponding tooth.

[0015] In one embodiment, the local excitation core and / or the longitudinal section of the local excitation core has a first side and a second side that are opposite and arc-shaped, the openings of the first side and the second side face the same direction, and the central angle corresponding to the first side is greater than the central angle corresponding to the second side.

[0016] The longitudinal section also has a first arc-shaped side connecting one end of the first side and one end of the second side, and a second arc-shaped side connecting the other end of the first side and the other end of the second side;

[0017] The contour formed by the first side, the second side, the first arc-shaped side, and the second arc-shaped side extends along the thickness direction to form a locally excitation core and / or a circulating current elimination core with thickness.

[0018] In one embodiment, a second recessed structure is formed on the surface of the local excitation core and / or the circulating current elimination core; the second recessed structure is located between two adjacent teeth of the stator core in contact with the local excitation core and / or the circulating current elimination core.

[0019] In one embodiment, the contact surfaces of the local excitation core and / or circulating current elimination core when they contact the teeth of the stator core are covered with an insulating medium.

[0020] In one embodiment, the local excitation core and / or the circulating current elimination core are provided with mounting holes, which are located at positions where the magnetic induction intensity is less than a preset intensity.

[0021] In one embodiment, the distance between the side of the local excitation core and / or the circulating current elimination core facing the faulty tooth and the other side of the local excitation core and / or the circulating current elimination core away from the faulty tooth is determined based on the width of the tooth and a preset number of contact teeth.

[0022] In one embodiment, the excitation windings on the local excitation core and the circulating current elimination core are energized.

[0023] Adjust the voltage value of the excitation winding of the local excitation core and / or circulating current eliminator core when they contact the teeth of the stator core based on the air gap.

[0024] In one embodiment, adjusting the voltage value for energizing the excitation winding of the local excitation core and / or the circulating current eliminator core based on the air gap when the teeth of the local excitation core and / or the circulating current eliminator core contact the stator core includes:

[0025] When the air gap between the teeth of the local excitation core and the stator core is greater than the air gap when the circulating current eliminates the air gap between the teeth of the core and the stator core, the voltage value for energizing the excitation winding of the local excitation core is increased.

[0026] When the air gap between the excitation core and the stator core teeth is less than that when the air gap between the core and the stator core teeth is eliminated by the circulating current, the voltage value for energizing the excitation winding of the circulating winding core is increased.

[0027] Secondly, this application also provides a method for detecting stator core faults, applied to the stator core fault detection system provided in the embodiments mentioned in the first aspect; the local excitation core contacts both sides of the faulty teeth of the lamination, while the faulty teeth do not contact the local excitation core; the method eliminates the contact between the core and the local excitation core at laminations located in different layers, and eliminates the contact between the core and the corresponding teeth of the lamination, while also eliminating contact between the core and the corresponding teeth of the lamination; the corresponding teeth and the faulty teeth are in the same row of teeth along the axial direction of the stator core; the method includes:

[0028] Energize the excitation windings on the local excitation core and the circulating current elimination core, respectively.

[0029] Adjust the voltage value of the excitation winding of the local excitation core and / or circulating current eliminator core when they contact the teeth of the stator core based on the air gap.

[0030] In one embodiment, adjusting the voltage value for energizing the excitation winding of the local excitation core and / or the circulating current eliminator core based on the air gap when the teeth of the local excitation core and / or the circulating current eliminator core contact the stator core includes:

[0031] When the air gap between the teeth of the local excitation core and the stator core is greater than the air gap when the circulating current eliminates the air gap between the teeth of the core and the stator core, the voltage value for energizing the excitation winding of the local excitation core is increased.

[0032] When the air gap between the excitation core and the stator core teeth is less than that when the air gap between the core and the stator core teeth is eliminated by the circulating current, the voltage value for energizing the excitation winding of the circulating winding core is increased.

[0033] The aforementioned stator core fault detection system and method include a multi-layer lamination, a local excitation core, and a circulating current elimination core. The laminations have teeth on their inner sides, and the multi-layer laminations are stacked to form the stator core. The local excitation core contacts the two sides of the faulty teeth on the lamination, but the faulty teeth do not contact the local excitation core. The circulating current elimination core is located at a lamination in a different layer from the local excitation core. The circulating current elimination core contacts the two sides of the corresponding teeth on the lamination, but does not contact the corresponding teeth on the lamination itself. The corresponding teeth and the faulty teeth are in the same row of teeth along the axial direction of the stator core. When using the local excitation core to excite the faulty teeth of the stator core, induced circulating currents are generated. Since a circulating current elimination core with the same appearance and quality as the local excitation core can be used, the generated induced circulating currents can be eliminated. This improves the situation where the local excitation core is difficult to excite due to the imbalance of magnetic flux in each branch of the stator winding. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is an application environment diagram of a stator core fault detection system in one embodiment;

[0036] Figure 2 This is a schematic diagram of a stator core fault detection system in one embodiment;

[0037] Figure 3 This is a flowchart illustrating a fault detection method for a stator core in one embodiment;

[0038] Figure 4 This is a schematic diagram of the stator core structure in one embodiment;

[0039] Figure 5 This is a schematic diagram of the structure of a partial excitation core in one embodiment;

[0040] Figure 6 This is a schematic diagram of a 4-tooth local excitation magnet core with a recessed structure and a stator core in one embodiment.

[0041] Figure 7 This is a schematic diagram of a 4-tooth local excitation magnet core with a recessed structure in one embodiment;

[0042] Figure 8 This is a schematic diagram of an optimized and improved 4-tooth local excitation magnet core with a recessed structure and a stator core in one embodiment.

[0043] Figure 9 This is a schematic diagram of an optimized and improved 4-tooth local excitation magnet core with a recessed structure in one embodiment.

[0044] Figure 10 This is a schematic diagram of the connection of the excitation windings on the local excitation core and the circulating current elimination core to a programmable power supply in one embodiment.

[0045] Figure 11 This is a circuit diagram illustrating the effect of a local excitation core on the double Y-shaped winding in one embodiment;

[0046] Figure 12 This is a magnetic circuit diagram of a locally excitable magnet core during local excitation in one embodiment.

[0047] Figure 13 This is an equivalent circuit diagram of the winding circulating current in one embodiment;

[0048] Figure 14 This is a circuit diagram of a transformer in one embodiment where the winding circulating current is equivalent to a secondary side short circuit;

[0049] Figure 15 This is an equivalent circuit diagram for eliminating winding circulating current in one embodiment;

[0050] Figure 16 A schematic diagram of an optimized and improved 4-tooth local excitation magnet core with mounting holes and a recessed structure in one embodiment.

[0051] Figure 17 This is an internal structural diagram of a computer device in one embodiment.

[0052] Explanation of reference numerals in the attached figures:

[0053] 202 - Lamination, 204 - Partial excitation core, 206 - Circulating winding core, 208 - Fault point, 402 - Excitation winding, 404 - Measuring winding, 406 - Stator core, 408 - Stator core teeth, 410 - Stator core yoke, 502 - Stator core yoke height 504 stator core tooth length 506-Stator core tooth width 602 - Second side edge, 604 - First side edge, 606 - First straight edge, 608 - Second straight edge, 610 - First recessed structure -Central angle, 802-First arc-shaped edge, 804-Second arc-shaped edge, 806-Second recessed structure, 1002-Control cabinet, 1004-Inside generator stator core. - Induction circulation, 1602 - Intersection of the center of the circle, 1604 - First end of the vertical line, 1606 - Third end of the vertical line, 1608 - Mounting hole, 1610 - First circle, 1612 - Second circle, 1614 - Second end of the vertical line. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0055] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0056] The stator core fault detection method provided in this application embodiment can be applied to, for example, Figure 1In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be integrated onto server 104 or placed on a cloud or other network server. Taking terminal 102 operating independently as an example, terminal 102 can energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206, respectively; based on the air gap when the local excitation core 204 and / or the circulating current elimination core 206 contacts the teeth of the stator core 406, the voltage value for energizing the excitation windings 402 of the local excitation core 204 and / or the circulating current elimination core 206 is adjusted.

[0057] Terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, drones, low-altitude aircraft, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, and projection equipment. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted displays. Head-mounted displays can be virtual reality (VR) devices, augmented reality (AR) devices, and smart glasses. Server 104 can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0058] In one exemplary embodiment, such as Figure 2 As shown, a fault detection system for a stator core is provided, wherein the stator core 406 includes multiple layers of laminations 202 arranged sequentially along its axial direction, and the laminations 202 are provided with teeth on their inner sides. The multiple layers of laminations 202 are stacked to form the stator core 406. The stator core 406 is cylindrical, and the teeth are arranged in a direction close to the central axis of the cylinder.

[0059] The stator core fault detection system includes:

[0060] The local excitation core 204 contacts both sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204.

[0061] The circulating current eliminator core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current eliminator core 206 contacts the two sides of the corresponding teeth of the lamination 202, but does not contact the corresponding teeth of the lamination 202. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core 406.

[0062] The lamination 202 is cylindrical, and each layer of lamination 202 has teeth on its inner side. These teeth are located in the direction close to the central axis of the cylinder. The multiple layers of lamination 202 are stacked along the central axis to form the stator core 406.

[0063] Among them, the faulty teeth of lamination 202 are determined by the ELCID method. The stator core 406 is composed of multiple layers of lamination 202. The fault point 208 of the faulty tooth is usually located at the top of the tooth far away from the stator core yoke 410, or at the bottom of the tooth connected to the stator core yoke 410.

[0064] The local excitation core 204 can be specifically a C-shaped iron core. The C-shaped iron core has two windings: an excitation winding 402 and a measuring winding 404. The excitation winding 402 is used to connect to a high-frequency power supply to locally excite the faulty tooth, and the measuring winding 404 is used to connect to a voltmeter to measure the voltage at the fault point.

[0065] The appearance quality of the circulating current eliminator core 206 is the same as that of the local excitation core 204. The circulating current eliminator core 206 is also wound with an excitation winding 402 and a measuring winding 404. The excitation winding 402 is used to connect to a high-frequency power supply for local excitation of the tooth corresponding to the faulty tooth. The measuring winding 404 is used to connect to a voltmeter to measure the generated voltage.

[0066] Furthermore, the excitation winding 402 on the circulating current eliminating core 206 and the excitation winding 402 on the local excitation core 204 have the same number of turns and opposite directions, so that the magnetomotive force generated by the circulating current eliminating core 206 and the local excitation core 204 is equal in magnitude and opposite in direction, making the total magnetomotive force of each phase stator winding linkage 0, thus no longer generating circulating current.

[0067] For example, when a faulty tooth of the stator core 406 is identified, a local excitation core 204 is placed across the non-faulty teeth on both sides of the faulty tooth, in contact with the non-faulty teeth but not with the faulty tooth, wherein the non-faulty teeth are adjacent to the faulty tooth. The number of teeth of the local excitation core 204 in contact with the stator core 406 is determined, and the local excitation core 204 is determined to be a multi-tooth local excitation core 204 based on the number of teeth of one end of the local excitation core 204 in contact with the stator core 406. For example, when the number of contact teeth is 2, that is, when one end of the local excitation core 204 contacts one tooth of the stator core 406 (the local excitation core 204 has a symmetrical structure, and its other end also contacts one tooth of the stator core 406, so the total number of contact teeth is 2, which is the number of contact teeth), the local excitation core 204 is a 1-tooth core, and the 1 tooth is the adjacent tooth of the faulty tooth. The number of contact teeth can be 2, 4, 6, 8, etc., and the corresponding local excitation core 204 is a 1-tooth core, a 2-tooth core, a 3-tooth core, a 4-tooth core, etc.

[0068] For example, such as Figure 4 and Figure 5 As shown, a high-frequency power supply is connected to the excitation winding 402 of the local excitation core 204, and a voltmeter is connected to the measuring winding 404 of the local excitation core 204. With the measuring winding 404 having only one turn, the voltage output by the measuring winding 404 is equal to the fault point voltage. To accurately determine whether fault point 208 truly exists, the fault point voltage generated by the local excitation method needs to be equal to the fault point voltage generated by the iron loss test. Specifically:

[0069] In the iron loss test, the yoke of the stator core 406 is energized to achieve a preset magnetic induction intensity, which could be 1.4T. If the magnetic induction intensity of the yoke of the stator core 406 is further increased, the stator core 406 will quickly enter a saturation state, leading to core damage. If a fault point 208 exists on the stator core 406, a fault current loop will be generated within the fault point 208.

[0070]

[0071] in, For the iron loss test fault current, The fault point voltage generated by the iron loss test. The circuit resistance at the fault point. The operating frequency during the iron loss test. It represents the magnetic flux density. Let be the area of ​​the yoke portion of the stator core, and This refers to the length of the teeth in the stator core. This refers to the height of the yoke of the stator core.

[0072] In the local excitation method, the fault point voltage generated by the local excitation method is:

[0073]

[0074] in, The frequency of the high-frequency power supply connected to the excitation winding 402, The magnetic induction intensity of the locally excited core 204. Let be the area of ​​the teeth of the stator core, and This refers to the tooth width of the stator core.

[0075] For large steam turbine generators, the yoke gear ratio It is usually around 8 to 10, therefore, when , hour, , and when achieve At this point, the local excitation core 204 reaches a pre-saturation state. If the [excitation core] is further increased... If this happens, the local excitation core 204 will quickly enter a saturation state, leading to overheating. Therefore, in order to increase the voltage at the local excitation fault point... , making It is necessary to increase the frequency of the high-frequency power supply. Alternatively, increase the contact area between the teeth of the local excitation core 204 and the stator core. and frequency When raised, the contact area of ​​the teeth Decrease; frequency When adjusted downwards, the contact area of ​​the teeth... Increase. Based on the above parameter relationships, it can be used to screen out the target number of contact teeth from at least one number of contact teeth.

[0076] For example, when a faulty tooth in the stator core 406 is identified, the appearance quality and placement position of the local excitation core 204 are determined, thereby determining the appearance quality and placement position of the current-eliminating core 206, and the appearance quality of the current-eliminating core 206 is the same as that of the local excitation core 204. Further, the current-eliminating core 206 is located at a lamination 202 on a different layer than the local excitation core 204, and the current-eliminating core 206 contacts both sides of the corresponding tooth of the lamination 202, but does not contact the corresponding tooth of the lamination 202; the corresponding tooth and the faulty tooth are the same row of teeth along the axial direction of the stator core 406.

[0077] For example, if the number of teeth in the faulty tooth of the stator core 406 is determined to be 2, and the local excitation core 204 is a 4-tooth core (i.e., the local excitation core 204 spans two teeth and three slots and contacts the adjacent non-faulty teeth on both sides of the faulty tooth), and the number of contacting teeth is 8, then the lamination 202 where the faulty tooth is located is obtained, and then any other lamination 202 of a different layer from the lamination 202 is obtained. This lamination 202 can be spaced 4 layers apart from the lamination 202 where the faulty tooth is located, and this lamination 202 is used to place the circulating current elimination core 206. Along the axial direction of the stator core 406, a tooth corresponding to the faulty tooth and the contacting tooth is determined at a lamination 202, and the circulating current elimination core 206 is placed in the corresponding tooth according to the placement position of the local excitation core 204. The two ends of the circulating current elimination core 206 are in contact with the corresponding contacting tooth, and the circulating current elimination core 206 is not in contact with the corresponding faulty tooth.

[0078] In this embodiment, the fault detection system of the stator core 406 includes multi-layer laminations 202, a local excitation core 204, and a circulating current elimination core 206. The laminations 202 have teeth on their inner sides, and the multi-layer laminations 202 are stacked to form the stator core 406. The local excitation core 204 contacts the two sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204. The circulating current elimination core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current elimination core 206 contacts the two sides of the corresponding teeth of the lamination 202 it is located in, but does not contact the corresponding teeth of the lamination 202 it is located in. The corresponding teeth and the faulty teeth are in the same row of teeth along the axial direction of the stator core 406. To address the issue of induced circulating currents generated when using a local excitation core 204 to excite faulty teeth of the stator core 406, the problem can be solved by eliminating the circulating current in the core 206 by setting a circulating current with the same appearance quality as the local excitation core 204. This eliminates the corresponding induced circulating currents and improves the problem of difficulty in exciting the local excitation core 204 due to the imbalance of magnetic flux in each branch of the stator winding.

[0079] In one embodiment, the preset number of contact teeth when the local excitation core 204 contacts the two sides of the faulty tooth is 4.

[0080] The preset number of contact teeth when the local excitation core 204 contacts the two sides of the faulty tooth is the same as the number of contact teeth when one end of the local excitation core 204 contacts one side of the faulty tooth. When the preset number of contact teeth when the local excitation core 204 contacts the two sides of the faulty tooth is 4, the local excitation core 204 is a 4-tooth iron core.

[0081] For example, in The highest is In order to ensure It needs to meet the following requirements: ,in Since the yoke area cannot be changed, the frequency of the high-frequency power supply must be increased. Alternatively, increase the contact area between the teeth of the local excitation core 204 and the stator core 406. and frequency When raised, the contact area of ​​the teeth Decrease; frequency When adjusted downwards, the contact area of ​​the teeth... Increase. The more teeth that contact the stator core 406 at both ends of the local excitation core 204, the greater the tooth contact area. The larger the value, the more important it is to compare the required excitation frequency, weight of the local excitation core 204, core tooth temperature, and bypass flux ratio when the number of teeth in contact between one end of the local excitation core 204 and the stator core 406 increases from 1 to 8 teeth, according to the finite element analysis method. The table below shows the comparison of these factors.

[0082] Table 1

[0083]

[0084] Based on the temperature of the teeth of the local excitation core 204 at an assumed ambient temperature of 40℃ in Table 1, it can be seen that since the temperature of the 3-tooth local excitation core 204 is 120.3℃, which is close to the allowable temperature of 130℃ for the stator winding, at least a 4-tooth local excitation core 204 should be used. Furthermore, the weight of 5-tooth or higher local excitation cores 204 increases significantly, the proportion of bypass flux is larger, and the flux efficiency of the local excitation core 204 decreases. Therefore, a 4-tooth local excitation core 204 is selected, and the frequency... Increase to 150Hz to ensure This allows for a certain amount of excitation margin during the experiment.

[0085] In this embodiment, by setting a 4-tooth local excitation magnet core 204 and selecting a suitable combination of tooth number and frequency, the bypass flux loss is small and the impact on the test results is small, ensuring that the generator stator core temperature does not exceed the stator winding insulation safety limit.

[0086] In one embodiment, please refer to Figure 6 and Figure 7 The longitudinal section of the local excitation core 204 and / or the circulating current elimination core 206 has a first side 604 and a second side 602 that are opposite and arc-shaped. The openings of the first side 604 and the second side 602 face the same direction, and the central angle corresponding to the first side 604 is... The central angle corresponding to the second side 602 The same; the longitudinal section also has a first straight edge 606 connecting one end of the first side 604 and one end of the second side 602, and a second straight edge 608 connecting the other end of the first side 604 and the other end of the second side 602; the contour formed by the first side 604, the second side 602, the first straight edge 606 and the second straight edge 608 extends along the thickness direction to form a local excitation core 204 and / or a circulating current elimination core 206 with thickness; the local excitation core 204 is provided with a first recessed structure 610 near and relative to the surface area of ​​the faulty tooth; the circulating current elimination core 206 is provided with a first recessed structure 610 near and relative to the surface area of ​​the corresponding tooth.

[0087] The thickness of the local excitation core 204 and / or the circulating current eliminator core 206 is determined based on the tooth width 506 of the stator core. The size of the first recessed structure 610 is determined based on the number of faulty teeth spanned by the local excitation core 204 and / or the circulating current eliminator core 206 and the number of turns of the excitation winding 402. The number of faulty teeth is used to determine the length of the first recessed structure 610; the more faulty teeth spanned by the local excitation core 204 and / or the circulating current eliminator core 206 and / or the corresponding number of teeth, the longer the first recessed structure 610. The number of turns of the excitation winding 402 is used to determine the depth of the first recessed structure 610; the more turns of the excitation winding 402, the deeper the first recessed structure 610.

[0088] For example, such as Figure 6 As shown, if the number of faulty teeth is determined to be 2, and the local excitation core 204 is a 4-tooth core, then the number of teeth in contact between one end of the local excitation core 204 and the stator core 406 is 4. Therefore, the local excitation core 204 spans two faulty tooth sections, and both ends of the local excitation core 204 are in contact with four non-faulty teeth adjacent to the faulty tooth section. Specifically, the two ends of the first side 604 of the longitudinal section of the local excitation core 204 are connected to the fourth non-faulty tooth adjacent to the faulty tooth section. The openings of the first side 604 and the second side 602 face the same direction, and the central angle corresponding to the first side 604... The central angle corresponding to the second side 602 The same, and the central angle The positions are all located away from the faulty tooth. In addition, one end of the first side 604 is connected to one end of the second side 602 to form a first straight side 606, and the other end of the first side 604 is connected to the other end of the second side 602 to form a second straight side 608. Then, the contour formed by the first side 604, the second side 602, the first straight side 606 and the second straight side 608 is extended along the thickness direction to form a local excitation core 204 with a thickness equal to the tooth length of the stator core tooth 408. A first recessed structure 610 is provided on the surface area of ​​the local excitation core 204 near and relative to the faulty tooth. The distance between the first side 604 and the second side 602 is the tooth length of four non-faulty teeth.

[0089] For example, if the number of faulty teeth is determined to be 2, then the corresponding number of teeth is also 2. When the local excitation core 204 is a 4-tooth core, the circulating current eliminator core 206 is also a 4-tooth core. The number of teeth contacting one end of the circulating current eliminator core 206 with the stator core 406 is 4. Therefore, the circulating current eliminator core 206 spans two corresponding tooth sections, and both ends of the circulating current eliminator core 206 contact four non-faulty teeth adjacent to the corresponding tooth section. The two ends of the first side 604 of the longitudinal section of the circulating current eliminator core 206 are respectively connected to the fourth non-faulty tooth adjacent to the corresponding tooth section. The openings of the first side 604 and the second side 602 face the same direction, and the central angle corresponding to the first side 604... The central angle corresponding to the second side 602 The same, and the central angle The positions are all located away from the corresponding teeth. In addition, one end of the first side 604 is connected to one end of the second side 602 to form a first straight side 606, and the other end of the first side 604 is connected to the other end of the second side 602 to form a second straight side 608. Then, the contour formed by the first side 604, the second side 602, the first straight side 606 and the second straight side 608 is extended along the thickness direction to form a circulating current elimination core 206 with a thickness equal to the tooth length of the stator core tooth 408; and a first recessed structure 610 is provided on the surface area of ​​the circulating current elimination core 206 near and relative to the corresponding tooth. The distance between the first side 604 and the second side 602 is the tooth length of four non-faulty teeth.

[0090] In this embodiment, by determining the local excitation core 204 and / or the circulating current elimination core 206 and setting the first recessed structure 610, it can be ensured that the local excitation core 204 and / or the circulating current elimination core 206 are in close contact with the non-faulty teeth of the stator core 406, and when windings are added to the local excitation core 204 and / or the circulating current elimination core 206 through the first recessed structure 610, they do not contact the faulty teeth and / or the corresponding teeth.

[0091] In one embodiment, see Figure 8 and Figure 9 The longitudinal section of the local excitation core 204 and / or the circulating current elimination core 206 has a first side 604 and a second side 602 that are opposite and arc-shaped. The openings of the first side 604 and the second side 602 face the same direction, and the central angle corresponding to the first side 604 is... The central angle greater than the second side 602 is The longitudinal section also has a first arc-shaped edge 802 connecting one end of the first side 604 and one end of the second side 602, and a second arc-shaped edge 804 connecting the other end of the first side 604 and the other end of the second side 602; the contour formed by the first side 604, the second side 602, the first arc-shaped edge 802 and the second arc-shaped edge 804 together extends along the thickness direction to form a locally excitation core 204 and / or a circulating current elimination core 206 with thickness.

[0092] For example, such as Figure 8 As shown, if the number of faulty teeth is determined to be 2, and the local excitation core 204 is a 4-tooth core, then the number of teeth contacted by one end of the local excitation core 204 with the stator core 406 is 4. Therefore, the local excitation core 204 spans two faulty tooth sections, and both ends of the local excitation core 204 contact the four non-faulty tooth sections adjacent to the faulty tooth. Specifically, the two ends of the first side 604 of the longitudinal section of the local excitation core 204 are connected to the first non-faulty tooth section closest to the faulty tooth, and the two ends of the second side 602 of the longitudinal section of the local excitation core 204 are connected to the fourth non-faulty tooth section adjacent to the faulty tooth. Both the first side 604 and the second side 602 are arc-shaped, and the openings of the first side 604 and the second side 602 face the same direction. The central angle corresponding to the first side 604... The central angle greater than the second side 602 is Two central angles The positions are all located in the direction of the faulty tooth. In addition, one end of the first side 604 and one end of the second side 602 are connected in an arc to form a first arc-shaped side 802, and the other end of the first side 604 and the other end of the second side 602 are connected in an arc to form a second arc-shaped side 804. The arc of the first arc-shaped side 802 and the second arc-shaped side 804 coincide with the arc formed by the four corresponding non-faulty teeth. Then, the contour formed by the first side 604, the second side 602, the first arc-shaped side 802 and the second arc-shaped side 804 is extended along the thickness direction to form a local excitation core 204 with thickness, which is the tooth length of the stator core tooth 408. The distance between the first side 604 and the second side 602 is the tooth length of the four non-faulty teeth.

[0093] For example, if the number of faulty teeth is determined to be 2, then the corresponding number of teeth is also 2. When the local excitation core 204 is a 4-tooth core, the circulating current eliminator core 206 is also a 4-tooth core. The number of teeth contacting one end of the circulating current eliminator core 206 with the stator core 406 is 4. Therefore, the circulating current eliminator core 206 spans 2 corresponding teeth, and both ends of the circulating current eliminator core 206 are in contact with 4 non-faulty teeth adjacent to the corresponding teeth. Specifically, the two ends of the first side 604 of the longitudinal section of the circulating current eliminator core 206 are connected to the first non-faulty tooth closest to the corresponding tooth, and the two ends of the second side 602 of the longitudinal section of the circulating current eliminator core 206 are connected to the fourth non-faulty tooth adjacent to the corresponding tooth. Both the first side 604 and the second side 602 are arc-shaped, and the openings of the first side 604 and the second side 602 face the same direction. The central angle corresponding to the first side 604... The central angle greater than the second side 602 is Two central angles The positions are all located in the direction of the corresponding teeth. In addition, one end of the first side 604 and one end of the second side 602 are connected in an arc to form a first arc-shaped side 802, and the other end of the first side 604 and the other end of the second side 602 are connected in an arc to form a second arc-shaped side 804. The arc of the first arc-shaped side 802 and the second arc-shaped side 804 coincide with the arc formed by the four corresponding non-faulty teeth. Then, the contour formed by the first side 604, the second side 602, the first arc-shaped side 802 and the second arc-shaped side 804 is extended along the thickness direction to form a circulating current elimination core 206 with thickness, which is the tooth length of the stator core tooth 408. The distance between the first side 604 and the second side 602 is the tooth length of the four non-faulty teeth.

[0094] In this embodiment, by setting the local excitation core 204 and / or the circulating current elimination core 206, the shape of the local excitation core 204 and / or the circulating current elimination core 206 is optimized, thereby reducing the weight of the local excitation core 204 and / or the circulating current elimination core 206 without affecting the normal operation of the local excitation core 204 and / or the circulating current elimination core 206.

[0095] In one embodiment, see Figure 8 A second recessed structure 806 is formed on the surface of the local excitation core 204 and / or the circulating current elimination core 206; the second recessed structure 806 is located between two adjacent teeth of the stator core 406 that are in contact with the local excitation core 204 and / or the circulating current elimination core 206.

[0096] The second recessed structure 806 is located at the position where the magnetic induction intensity is lowest when the local excitation core 204 and / or the circulating current elimination core 206 are working. The position where the magnetic induction intensity is lowest is located between two adjacent teeth of the stator core 406 and the local excitation core 204 and / or the circulating current elimination core 206.

[0097] For example, after determining the shape of the local excitation core 204 and / or the circulating current elimination core 206, according to the magnetic induction intensity distribution within the local excitation core 204 and / or the circulating current elimination core 206 during operation, a second recessed structure 806 is formed at a location with lower magnetic induction intensity. This further reduces the weight of the local excitation core 204 and / or the circulating current elimination core 206 without affecting its normal operation, thus avoiding meaningless weight gain caused by locations with extremely low utilization rates in the local excitation core 204 and / or the circulating current elimination core 206.

[0098] In this embodiment, by providing the second recessed structure 806, the weight of the local excitation core 204 and / or the circulating current elimination core 206 can be reduced, thereby improving the utilization rate of the local excitation core 204 and / or the circulating current elimination core 206.

[0099] In one embodiment, the contact surfaces of the local excitation core 204 and / or the circulating current elimination core 206 when they contact the teeth of the stator core 406 are covered with an insulating medium; and preferably, the thickness of the insulating medium is 0.2 mm.

[0100] The insulating medium can be, but is not limited to, 0.2mm thick blue paper. If the insulating medium is too thin, it is easy to break; if the insulating medium is too thick, the magnetic reluctance is high. The insulating medium is used as a non-metallic protective material to wrap the contact surface when the teeth of the local excitation core 204 and / or the circulating current eliminator core 206 contact the stator core 406.

[0101] In this embodiment, the insulating medium can prevent the local excitation core 204 and / or the circulating current elimination core 206 from directly contacting the stator core 406, thereby avoiding metal-to-metal contact that could damage the stator core 406.

[0102] In one embodiment, the distance between the side of the local excitation core 204 and / or the circulating current eliminator core 206 facing the faulty tooth and the other side of the local excitation core 204 and / or the circulating current eliminator core 206 away from the faulty tooth is determined according to the width of the tooth and a preset number of contact teeth; and the local excitation core 204 and / or the circulating current eliminator core 206 is provided with a mounting hole 1608, which is located at a position where the magnetic induction intensity of the local excitation core 204 and / or the circulating current eliminator core 206 is relatively small.

[0103] The side of the local excitation core 204 facing the faulty tooth refers to the side of the local excitation core 204 that is close to the faulty tooth and the opening of this side faces the faulty tooth; the other side of the local excitation core 204 away from the faulty tooth refers to the other side of the local excitation core 204 that is far from the faulty tooth and the bending direction of the other side is away from the faulty tooth.

[0104] The side of the circulating current eliminator core 206 facing the faulty tooth refers to the side of the circulating current eliminator core 206 that is close to the corresponding tooth and the opening of this side faces the corresponding tooth, wherein the corresponding tooth and the faulty tooth are the same row of teeth along the axial direction of the stator core; the other side of the circulating current eliminator core 206 away from the corresponding tooth refers to the other side of the circulating current eliminator core 206 that is far away from the corresponding tooth and the bending direction of the other side is away from the corresponding tooth.

[0105] For example, if the number of faulty teeth is determined to be 2, and the local excitation core 204 is a 4-tooth iron core, the number of teeth that one end of the local excitation core 204 contacts the stator iron core 406 is 4. Then the local excitation core 204 spans 2 faulty teeth, and both ends of the local excitation core 204 are in contact with 4 non-faulty teeth adjacent to the faulty teeth. The total tooth width of these 4 teeth is calculated, and the total tooth width is used as the distance between the side of the local excitation core 204 facing the faulty teeth and the other side of the local excitation core 204 away from the faulty teeth.

[0106] For example, if the number of faulty teeth is determined to be 2, then the corresponding number of teeth is also 2. When the local excitation core 204 is a 4-tooth core, the circulating current eliminator core 206 is also a 4-tooth core. The number of teeth that contact one end of the circulating current eliminator core 206 with the stator core 406 is 4. Then the circulating current eliminator core 206 spans 2 corresponding teeth, and both ends of the circulating current eliminator core 206 contact 4 non-faulty teeth adjacent to the corresponding teeth. The total tooth width of these 4 teeth is calculated, and this total tooth width is used as the distance between the side of the circulating current eliminator core 206 facing the corresponding tooth and the other side of the circulating current eliminator core 206 away from the corresponding tooth.

[0107] For example, the local excitation core 204 and / or the circulating current eliminator core 206 can also be composed of multiple layers of laminations, and the local excitation core 204 and / or the circulating current eliminator core 206 are provided with mounting holes 1608, through which multiple layers of laminations are stacked to obtain the local excitation core 204 and / or the circulating current eliminator core 206. The mounting holes 1608 are located at positions where the magnetic induction intensity is less than a preset intensity, so as not to affect the overall performance of the local excitation core 204 and / or the circulating current eliminator core 206.

[0108] In this embodiment, the distance between the two surfaces of the local excitation core 204 and / or the circulating current elimination core 206 is obtained by the total tooth width of the preset number of contact teeth, thereby ensuring that the yoke of the local excitation core 204 and / or the circulating current elimination core 206 is fully utilized and will not saturate before the teeth.

[0109] In one embodiment, such as Figure 3 As shown, a fault detection method for stator cores is provided, which is applied to... Figure 1 Taking the terminal in the example, the explanation includes the following steps 302 to 308. Wherein:

[0110] Step 302, the local excitation core 204 contacts the two sides of the faulty teeth of the lamination 202, and the faulty teeth do not contact the local excitation core 204.

[0111] Step 304: The circulating current elimination core 206 is located at a lamination 202 in a different layer from the local excitation core 204. The circulating current elimination core 206 contacts the two sides of the corresponding tooth of the lamination 202, but does not contact the corresponding tooth of the lamination 202. The corresponding tooth and the faulty tooth are the same row of teeth along the axial direction of the stator core 406.

[0112] Step 306: Energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206.

[0113] For example, such as Figure 10 As shown, two independent programmable power supplies are used to synchronously energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206. The voltages of the two independent programmable power supplies are in phase, synchronously increasing from 0 and synchronously reaching their maximum values, thereby keeping the total flux induced in the stator windings at 0. The two independent programmable power supplies are connected together using a TRIG terminal.

[0114] For example, a large generator adopts a double-Y structure. After a programmable power supply energizes the excitation winding 402 on the local excitation core 204, the circuit diagram showing the effect of local excitation on the double-Y winding is as follows. Figure 11 As shown, where For induced circulation, and the equivalent local excitation magnetic circuit diagram is as follows: Figure 12 As shown, where, This is the voltage of the programmable power supply. This is the equivalent resistance of the air gap. This is the equivalent resistance for normal core losses. The resistance at the fault point. The faulty leakage magnetic reluctance, The fault current magnetomotive force. Figure 13The equivalent circuit diagram for the circulating current in the winding is shown below. The resistance of the excitation coil. For the leakage reactance of the excitation coil, This is the equivalent resistance of the C-type iron core loss. It is a C-type iron core magnetizing reactor. For air gap equivalent reactance, The equivalent resistance for core tooth loss. The equivalent impedance for iron core tooth loss. The equivalent resistance for bypass core losses. For bypass core magnetizing reactor, The equivalent resistance of the iron core yoke loss. For the core yoke excitation reactance; Figure 14 The circuit diagram is for a transformer where the winding circulating current is equivalent to a secondary side short circuit. The equivalent resistance of the faulty iron core loss. For the faulty iron core magnetizing reactor, For the fault circuit resistance, This is the leakage reactance of the faulty circuit.

[0115] For example, after simultaneously energizing the excitation windings 402 on both the local excitation core 204 and the circulating current elimination core 206, the equivalent circuit diagram for eliminating the circulating current in the windings is as follows: Figure 15 As shown, at this time, the local excitation core 204 and the circulating current elimination core 206 generate opposite magnetic fluxes, thereby eliminating the induced circulating current generated by the local excitation core 204.

[0116] Step 308: Adjust the voltage value of the excitation winding 402 of the local excitation core 204 and / or the circulating current elimination core 206 when they contact the teeth of the stator core 406.

[0117] Among them, the air gap refers to the tiny gap filled with air that exists between the local excitation core 204 and / or the circulating current elimination core 206 and the stator core 406 because they cannot make complete tight contact.

[0118] For example, the voltage value of the excitation winding 402 is dynamically adjusted according to the air gap when the teeth of the local excitation core 204 and the stator core 406 are in contact and the size of the air gap when the teeth of the circulating current elimination core 206 and the stator core 406 are in contact.

[0119] In this embodiment, two synchronously input and individually adjustable programmable power supplies can generate magnetic fluxes of equal magnitude and opposite direction on the local excitation core 204 and the circulating current elimination core 206, thereby eliminating the winding circulating current generated when the local excitation core 204 excites the fault point 208.

[0120] In one embodiment, adjusting the voltage value for energizing the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206 when they contact the teeth of the stator core 406, includes: increasing the voltage value for energizing the excitation winding 402 of the local excitation core 204 when the air gap between the local excitation core 204 and / or the circulating current eliminator core 206 and the teeth of the stator core 406 is greater than the air gap between the circulating current eliminator core 206 and the teeth of the stator core 406; and increasing the voltage value for energizing the excitation winding 402 of the circulating current winding core when the air gap between the local excitation core 204 and / or the teeth of the stator core 406 is less than the air gap between the circulating current eliminator core 206 and the teeth of the stator core 406.

[0121] For example, because the parallelism of the local excitation core 204 and the circulating current eliminator core 206 is not completely consistent, the air gaps at some contact teeth are unequal, resulting in unequal voltage values ​​and magnetic flux generated by the two cores for excitation. Furthermore, based on the air gaps when the local excitation core 204 and / or the circulating current eliminator core 206 contact the teeth of the stator core 406, when the local excitation core 204 contacts the teeth of the stator core 406... When the air gap is greater than the air gap when the teeth of the circulating core 206 and the stator core 406 are in contact, the voltage value for energizing the excitation winding 402 of the local excitation core 204 is increased; when the air gap when the teeth of the local excitation core 204 and the stator core 406 are in contact is less than the air gap when the teeth of the circulating core 206 and the stator core 406 are in contact, the voltage value for energizing the excitation winding 402 of the circulating core is increased.

[0122] In this embodiment, based on the size of the air gap when the two iron cores are in contact with the stator iron core 406, the power supply voltage value with the larger air gap is increased to maintain the magnetic flux of the two iron core circuits being equal in magnitude and opposite in direction, so that no circulating current is generated in the stator winding.

[0123] A specific embodiment illustrates a method for detecting stator core faults, comprising the following steps:

[0124] Step (1) Determine the fault point 208 of the stator core 406 using the ELCID method. Place the local excitation core 204 across the teeth on both sides of the suspected fault point 208 to locally excite the fault point 208. The local excitation core 204 has two windings: an excitation winding 402 and a measuring winding 404, which are connected to a high-frequency power supply and a voltmeter, respectively. Specifically:

[0125] The excitation winding 402 is connected to a high-frequency power supply to excite the local excitation core 204. A voltmeter is connected to the measuring winding 404 to measure the output voltage. When the measuring winding 404 has only one turn, this output voltage is the local excitation fault point voltage. To determine whether the fault point 208 truly exists using the local excitation method, the local excitation fault point voltage needs to be... Induced voltage at the fault point of the iron loss test Equal, that is,

[0126]

[0127] in, , , , This refers to the contact area when the two ends of the local excitation core 204 come into contact with one tooth of the stator core 406.

[0128] If the excitation frequency , hour, ,when achieve At that time, the local excitation core 204 reaches a pre-saturation state. If the temperature is further increased... If this happens, the local excitation core 204 will quickly enter a saturation state, leading to overheating. Therefore, in order to increase the voltage at the local excitation fault point... The frequency of the high-frequency power supply needs to be increased to... of This can be repeated several times. At the same time, higher frequencies can be used, and the magnetic induction intensity can be reduced proportionally. To maintain the voltage at the local excitation fault point Induced voltage at the fault point of the iron loss test equal.

[0129] Step (2) Select a 4-tooth local excitation core 204 and optimize its shape and quality. Specifically:

[0130] Based on Table 1 above, a 4-tooth local excitation magnet core 204 is selected, and then the shape and quality of the 4-tooth local excitation magnet core 204 are optimized, such as... Figure 8 As shown. If the fault point 208 is located at the position where the middle slot of the two stator core teeth 408 connects to the stator core yoke 410, then both stator core teeth 408 are regarded as fault teeth, and the local excitation core 204 spans across these two fault teeth.

[0131] First, connect the tips of the first non-faulty tooth spanning the two-tooth, three-slot adjacent faulty tooth section, find the midpoint of the straight line, and draw a perpendicular line through the midpoint, with the center intersection point 1604 coinciding with the midpoint. The second end of the perpendicular line is away from the stator core tooth section 408, and the length of the perpendicular line is 50mm. Draw an arc through the tips of the two first non-faulty teeth and the second end 1614 of the perpendicular line, thus obtaining the first side 604 of the longitudinal section of the local excitation core 204. The length of the perpendicular line is determined by the number of turns of the excitation winding 402 of the local excitation core 204, thereby ensuring that the local excitation core 204 does not come into contact with the faulty tooth after the excitation winding 402 is wound.

[0132] Secondly, extend the vertical line from the second end 1614 to the third end. Determine the width of the yoke of the local excitation core 204 based on the length of the extended vertical line. This width is set to the width of the four stator core teeth 408, where the width of the stator core teeth 408 is approximately 55mm. Therefore, the width of the yoke of the local excitation core 204 should be set to 4 * 55mm = 220mm, ensuring that the yoke of the local excitation core 204 is fully utilized and does not saturate before the teeth. Draw an arc through the tips of the fourth non-faulty tooth (two teeth far from the faulty tooth) and the third end of the vertical line to obtain the second side 602 of the longitudinal section of the local excitation core 204.

[0133] Next, one end of the first side 604 is connected to one end of the second side 602 in an arc shape to form a first arc-shaped side 802, and the other end of the first side 604 is connected to the other end of the second side 602 in an arc shape to form a second arc-shaped side 804. The arc of the first arc-shaped side 802 and the second arc-shaped side 804 coincide with the arc formed by their corresponding four non-faulty teeth. Then, a circle is drawn with the groove width of the stator core 406 as the diameter, and the circle is moved between two adjacent non-faulty teeth. The part of the local excitation core 204 that overlaps with the circle is cut off. This overlapping part is a weight-reducing semicircle, thus obtaining the first arc-shaped side 802 and the second arc-shaped side 804 after the cutting operation. This weight-reducing semicircle is the part of the local excitation core 204 with lower magnetic induction intensity. Then, the contour formed by the first arcuate edge 802 and the second arcuate edge 804, as well as the first side edge 604 and the second side edge 602, is extended along the thickness direction to form a local excitation core 204 with a thickness equal to the tooth length of the stator core tooth 408.

[0134] Finally, as Figure 16Draw a circle along the second side 602 of the longitudinal section of the local excitation core 204, find its center position, and then draw two circles with the same center. The first circle 1610 should pass through the middle of the weight reduction semicircle between the third and fourth non-faulty teeth, which are far away from the faulty tooth. The second circle 1612 should pass through the middle of the weight reduction semicircle between the second and third non-faulty teeth, which are far away from the faulty tooth. Then, using the center of the circle as the intersection point, draw straight lines based on the center and the intersection point 1602. Draw four straight lines with angles of 8° and 12° in clockwise and counterclockwise directions respectively. Then, select the intersection points of the two straight lines with an angle of 12° with the first circle 1610, and the intersection points of the two straight lines with an angle of 8° with the second circle 1612, as the positions of the mounting holes 1608 of the local excitation core 204. Using the four intersection points as the centers, draw circles with a diameter of 12mm. The size of these circles is the size of the mounting holes 1608.

[0135] Step (3) Based on the shape, mass, and placement of the local excitation core 204, determine the shape, mass, and placement of the circulating current elimination core 206. Specifically,

[0136] The shape and mass of the circulating current eliminator core 206 are completely identical to those of the local excitation core 204. The circulating current eliminator core 206 also has an excitation winding 402 and a measuring winding 404 wound around it. The excitation winding 402 is used to connect to a high-frequency power supply to locally excite the tooth corresponding to the faulty tooth, and the measuring winding 404 is used to connect to a voltmeter to measure the generated voltage. Furthermore, the excitation winding 402 on the circulating current eliminator core 206 and the excitation winding 402 on the local excitation core 204 have the same number of turns but opposite directions. Therefore, the circulating current eliminator core 206 and the local excitation core 204 generate magnetomotive forces of equal magnitude and opposite direction, resulting in a total magnetomotive force of zero linkage in each phase stator winding, thus eliminating circulating current.

[0137] In the case of identifying the faulty tooth of the stator core 406, the appearance quality and placement of the local excitation core 204 are determined, thereby determining the appearance quality and placement of the circulating current elimination core 206. Specifically, the number of teeth in the faulty tooth section of the stator core 406 is determined to be 2, and the local excitation core 204 is a 4-tooth core, that is, the local excitation core 204 spans two teeth and three slots and contacts the adjacent non-faulty teeth on both sides of the faulty tooth section. When the number of contacting teeth is 8, the lamination 202 where the faulty tooth section is located is obtained, and then any other lamination 202 of different layers from the lamination 202 is obtained. This lamination 202 can be spaced 4 layers apart from the lamination 202 where the faulty tooth section is located, and this lamination 202 is used to place the circulating current elimination core 206. Along the axial direction of the stator core 406, the teeth corresponding to the faulty tooth section and the contacting teeth section are determined at a lamination 202, and the circulating current elimination core 206 is placed in the corresponding tooth section according to the placement position of the local excitation core 204. The two ends of the circulating current elimination core 206 are in contact with the corresponding contacting teeth section, and the circulating current elimination core 206 is not in contact with the corresponding faulty tooth section.

[0138] Step (4) uses two independent programmable power supplies, which are respectively connected to the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206. Specifically:

[0139] like Figure 10 As shown, the excitation winding 402 on the local excitation core 204 is connected to one programmable power supply, and the excitation winding 402 on the circulating current elimination core 206 is connected to another programmable power supply. The voltages of the two independent programmable power supplies are in phase, and they are connected together using a TRIG terminal. When the excitation winding 402 is energized, the two independent programmable power supplies need to synchronously increase from 0 and synchronously reach their maximum values ​​to keep the total flux linkage induced in the stator winding at 0.

[0140] Step (5) Dynamically adjust the voltage value of the excitation winding 402 of each core to be energized based on the air gap size when the two cores contact the teeth of the stator core 406. Specifically:

[0141] Because the parallelism of the local excitation core 204 and the circulating current eliminator core 206 is not completely consistent, the air gaps of some contact teeth are not equal, resulting in unequal excitation voltages and magnetic fluxes generated by the two cores. Furthermore, based on the air gaps when the local excitation core 204 and / or the circulating current eliminator core 206 contact the teeth of the stator core 406, if the air gap when the local excitation core 204 contacts the teeth of the stator core 406 is greater than the air gap when the circulating current eliminator core 206 contacts the teeth of the stator core 406, the voltage value for energizing the excitation winding 402 of the local excitation core 204 is increased; if the air gap when the local excitation core 204 contacts the teeth of the stator core 406 is less than the air gap when the circulating current eliminator core 206 contacts the teeth of the stator core 406, the voltage value for energizing the excitation winding 402 of the circulating current winding core is increased.

[0142] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0143] In one exemplary embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 17As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When the computer program is executed by the processor, it implements a method for detecting faults in the stator core.

[0144] Those skilled in the art will understand that Figure 17 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0145] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0146] The local excitation core 204 contacts both sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204.

[0147] The circulating current eliminator core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current eliminator core 206 contacts the two sides of the corresponding teeth of the lamination 202, but does not contact the corresponding teeth of the lamination 202. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core 406.

[0148] Energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206 respectively;

[0149] The voltage value at which the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206 is energized is adjusted according to the air gap when they contact the teeth of the stator core 406.

[0150] In one embodiment, the processor, when executing a computer program, also performs the following steps:

[0151] Based on the air gap when the local excitation core 204 and / or the circulating current eliminator core 206 contact the teeth of the stator core 406, adjust the voltage value for energizing the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206, including:

[0152] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is greater than the air gap when the circulating current eliminates the air gap between the teeth of the core 206 and the stator core 406, the voltage value for energizing the excitation winding 402 of the local excitation core 204 is increased.

[0153] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is smaller than that when the air gap between the core 206 and the teeth of the stator core 406 is eliminated by the circulating current, the voltage value for energizing the excitation winding 402 of the circulating winding core is increased.

[0154] The implementation principle and technical effects of the above embodiments are similar to those of the above method embodiments, and will not be repeated here.

[0155] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, the computer program performing the following steps when executed by a processor:

[0156] The local excitation core 204 contacts both sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204.

[0157] The circulating current eliminator core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current eliminator core 206 contacts the two sides of the corresponding teeth of the lamination 202, but does not contact the corresponding teeth of the lamination 202. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core 406.

[0158] Energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206 respectively;

[0159] The voltage value at which the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206 is energized is adjusted according to the air gap when they contact the teeth of the stator core 406.

[0160] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0161] The local excitation core 204 contacts both sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204.

[0162] The circulating current eliminator core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current eliminator core 206 contacts the two sides of the corresponding teeth of the lamination 202, but does not contact the corresponding teeth of the lamination 202. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core 406.

[0163] Based on the air gap when the local excitation core 204 and / or the circulating current eliminator core 206 contact the teeth of the stator core 406, adjust the voltage value for energizing the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206, including:

[0164] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is greater than the air gap when the circulating current eliminates the air gap between the teeth of the core 206 and the stator core 406, the voltage value for energizing the excitation winding 402 of the local excitation core 204 is increased.

[0165] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is smaller than that when the air gap between the core 206 and the teeth of the stator core 406 is eliminated by the circulating current, the voltage value for energizing the excitation winding 402 of the circulating winding core is increased.

[0166] The implementation principle and technical effects of the above embodiments are similar to those of the above method embodiments, and will not be repeated here.

[0167] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, performs the following steps:

[0168] The local excitation core 204 contacts both sides of the faulty teeth of the lamination 202, but the faulty teeth do not contact the local excitation core 204.

[0169] The circulating current eliminator core 206 and the local excitation core 204 are located at laminations 202 in different layers. The circulating current eliminator core 206 contacts the two sides of the corresponding teeth of the lamination 202, but does not contact the corresponding teeth of the lamination 202. The corresponding teeth and the faulty teeth are the same row of teeth along the axial direction of the stator core 406.

[0170] Energize the excitation windings 402 on the local excitation core 204 and the circulating current elimination core 206 respectively;

[0171] The voltage value at which the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206 is energized is adjusted according to the air gap when they contact the teeth of the stator core 406.

[0172] In one embodiment, when the computer program is executed by a processor, it also performs the following steps:

[0173] Based on the air gap when the local excitation core 204 and / or the circulating current eliminator core 206 contact the teeth of the stator core 406, adjust the voltage value for energizing the excitation winding 402 of the local excitation core 204 and / or the circulating current eliminator core 206, including:

[0174] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is greater than the air gap when the circulating current eliminates the air gap between the teeth of the core 206 and the stator core 406, the voltage value for energizing the excitation winding 402 of the local excitation core 204 is increased.

[0175] When the air gap between the local excitation core 204 and the teeth of the stator core 406 is smaller than that when the air gap between the core 206 and the teeth of the stator core 406 is eliminated by the circulating current, the voltage value for energizing the excitation winding 402 of the circulating winding core is increased.

[0176] The implementation principle and technical effects of the above embodiments are similar to those of the above method embodiments, and will not be repeated here.

[0177] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0178] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0179] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0180] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A fault detection system of a stator core including a plurality of laminations arranged in series along an axial direction thereof, the laminations being provided with tooth portions on inner sides thereof, characterized by, The system comprises: a local excitation core, which is in contact with two side tooth portions of a fault tooth portion of the punching sheet, the fault tooth portion not being in contact with the local excitation core; a circulating current elimination core, which is at the punching sheet at a different layer from the local excitation core, is in contact with two side tooth portions of a corresponding tooth portion of the punching sheet, and is not in contact with the corresponding tooth portion of the punching sheet; the corresponding tooth portion and the fault tooth portion are the same column tooth portions in the axial direction of the stator core.

2. The system of claim 1, wherein, The local excitation core is in contact with the two side tooth portions of the fault tooth portion by a preset contact tooth number of 4.

3. The system of claim 1, wherein, The longitudinal section of the local excitation core and / or the circulating current elimination core has opposite and arc-shaped first and second side edges, the opening directions of the first and second side edges are consistent, and the corresponding central angles of the first and second side edges are the same. The longitudinal section further has a first straight edge connecting one end of the first side edge and one end of the second side edge, and a second straight edge connecting the other end of the first side edge and the other end of the second side edge. The first side edge, the second side edge, the first straight edge, and the second straight edge together enclose a profile that extends in the thickness direction to form the local excitation core and / or the circulating current elimination core with thickness. The local excitation core is provided with a first recess structure near and opposite to the surface area of the fault tooth portion. The circulating current elimination core is provided with a first recess structure near and opposite to the surface area of the corresponding tooth portion.

4. The system of claim 1, wherein, The longitudinal section of the local excitation core and / or the circulating current elimination core has opposite and arc-shaped first and second side edges, the opening directions of the first and second side edges are consistent, and the corresponding central angles of the first and second side edges are the same. The longitudinal section further has a first arc-shaped edge connecting one end of the first side edge and one end of the second side edge, and a second arc-shaped edge connecting the other end of the first side edge and the other end of the second side edge. The first side edge, the second side edge, the first arc-shaped edge, and the second arc-shaped edge together enclose a profile that extends in the thickness direction to form the local excitation core and / or the circulating current elimination core with thickness.

5. The system of any one of claims 1 to 4, wherein, The surface of the local excitation core and / or the circulating current elimination core is formed with a second recess structure; the second recess structure is located between two adjacent tooth portions of the stator core in contact with the local excitation core and / or the circulating current elimination core.

6. The system of any one of claims 1 to 4, wherein, The contact surface of the local excitation core and / or the circulating current elimination core in contact with the tooth portion of the stator core is wrapped with an insulating medium.

7. The system of any one of claims 1 to 4, wherein, The local excitation core and / or the circulating current elimination core is provided with a mounting hole located at a position with a magnetic induction intensity less than a preset intensity.

8. The system of any one of claims 1 to 4, wherein, The distance between the side of the local excitation core and / or the circulating current elimination core facing the fault tooth portion and the side of the local excitation core and / or the circulating current elimination core away from the fault tooth portion is determined according to the width of the tooth portion and a preset contact tooth number.

9. A method of detecting a fault of a stator core, characterized by, The application is applied to the fault detection system of the stator core in any one of claims 1 to 8; the local excitation core is in contact with the two side teeth of the fault tooth of the punching sheet, the fault tooth is not in contact with the local excitation core; the circulating current elimination core is at the punching sheet of different layers with the local excitation core, the circulating current elimination core is in contact with the two side teeth of the corresponding tooth of the punching sheet, and is not in contact with the corresponding tooth of the punching sheet; the corresponding tooth and the fault tooth are the same column teeth in the axial direction of the stator core; the method comprises: The excitation winding of the local excitation core and the circulating current elimination core is energized; According to the air gap when the local excitation core and / or the circulating current elimination core is in contact with the tooth of the stator core, the voltage value of the excitation winding of the local excitation core and / or the circulating current elimination core is adjusted.

10. The method of claim 9, wherein, The voltage value of the excitation winding of the local excitation core and / or the circulating current elimination core is adjusted according to the air gap when the local excitation core and / or the circulating current elimination core is in contact with the tooth of the stator core, comprising: In the case that the air gap when the local excitation core is in contact with the tooth of the stator core is greater than the air gap when the circulating current elimination core is in contact with the tooth of the stator core, the voltage value of the excitation winding of the local excitation core is increased; In the case that the air gap when the local excitation core is in contact with the tooth of the stator core is less than the air gap when the circulating current elimination core is in contact with the tooth of the stator core, the voltage value of the excitation winding of the circulating current elimination core is increased.

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