Stator, generator, wind turbine generator set, and Anti-corona treatment method

Abstract

The present application discloses a stator, a generator, a wind turbine generator set, and an anti-corona treatment method. The stator comprises an iron core and a winding; a plurality of mounting slots are distributed at intervals in the iron core in the circumferential direction; the winding is arranged on the iron core, and the winding comprises a plurality of branches; each branch comprises a plurality of coils; each mounting slot is internally provided with one coil; each coil has end parts protruding out of the iron core on the two sides of the iron core in the axial direction; at least one branch is provided with a potting layer, and the potting layer covers the end parts of some of the plurality of coils of the branches; and the working voltage of some of the coils when the generator works at a rated voltage is greater than a voltage anti-corona threshold.

Description

Stator, generator, wind turbine generator set and anti-corona treatment method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202310935110.6 filed on July 27, 2023, entitled “Stator, generator, wind turbine generator set and anti-corona treatment method,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of generators, and in particular to a stator, a generator, a wind turbine generator set, and an anti-corona treatment method. Background Art

[0004] At present, wind turbines (also referred to as wind turbines or wind turbines) generally use generators with a rated voltage of 10kV. It is possible to consider increasing the rated voltage of the generator to 35kV, even if the generator is directly connected to the wind farm's substation (35kV to 110kV / 220kV) after generating electricity. In this way, the transformer (the capacity of the transformer is equivalent to the capacity of the wind turbine and is expensive, generally costing more than one million) can be saved. In addition, the low / medium voltage and high current cables between the generator and the transformer can be saved, further saving costs and space.

[0005] The coil ends of a high-voltage generator stator are in contact with the air. The conductors at these ends have a high potential, leading to deformation-induced electric field distortion and high electric field strength, which can easily generate corona. Existing anti-corona structures at the coil ends of high-voltage generator stators generally use a low-resistance band and a high-resistance band for transition. However, for ultra-high-voltage generators (e.g., 27kV to 35kV), this anti-corona design at the coil ends no longer meets the anti-corona requirements.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a stator, a generator, a wind turbine generator set, and an anti-corona treatment method. The stator can meet the anti-corona requirements of the coil ends at higher voltage levels.

[0008] In a first aspect, an embodiment of the present application provides a stator, comprising: an iron core, wherein the iron core has a plurality of mounting slots spaced apart in its circumferential direction; a winding, arranged on the iron core, the winding comprising a plurality of branches, each branch comprising a plurality of coils, a coil being arranged in each mounting slot, the coil having ends protruding from the iron core on both sides in the axial direction of the iron core; wherein at least one branch is provided with a potting layer, the potting layer covering ends of a portion of the plurality of coils of the branch; wherein the operating voltage of the portion of the coils is greater than the voltage anti-corona threshold when the generator operates at the rated voltage.

[0009] In a possible implementation manner of the first aspect, the voltage anti-corona threshold is less than or equal to a maximum anti-corona voltage that the end of the coil can withstand based on its own anti-corona structure.

[0010] In a possible implementation manner of the first aspect, the voltage anti-corona threshold is greater than 20 kV.

[0011] In a possible implementation of the first aspect, for any branch, a portion of the coils includes N consecutive coils along a first clockwise direction, starting from the coil connected to the phase lead wire in the branch, wherein the first clockwise direction includes one of a clockwise direction and a counterclockwise direction, and N is determined by the ratio of the voltage width with anti-corona compensation requirements to the voltage drop of a single-layer coil, and N is less than the total number of coils included in the branch.

[0012] In a possible implementation manner of the first aspect, the voltage width with the anti-corona compensation requirement is obtained by subtracting the rated voltage of the generator from the voltage anti-corona threshold.

[0013] In a possible implementation manner of the first aspect, each branch is provided with a potting layer.

[0014] In a possible implementation of the first aspect, the multiple coils of each branch are wound circumferentially along a first clockwise direction, and one of the multiple coils of each branch is connected to a phase lead wire; the potting layer corresponding to each branch includes a first potting portion, which starts from the coil in the branch connected to the phase lead wire and continuously covers N coils along the first clockwise direction, where N is less than the total number of coils included in the branch, and the first clockwise direction includes one of a clockwise direction and a counterclockwise direction.

[0015] In a possible implementation of the first aspect, the potting layer corresponding to each branch also includes a second potting portion, the second potting portion starting from the coil connected to the phase lead wire in the branch, covering at least one coil along the second clockwise direction, and the first clockwise direction and the second clockwise direction are arranged opposite to each other in the circumferential direction.

[0016] In a possible implementation manner of the first aspect, a wire connection line is provided at one end of the coil, the coils in the same branch are connected via the wire connection line, and the wire connection line is potted and coated.

[0017] In a possible implementation of the first aspect, a cover plate is provided at the outlet of the installation slot, the cover plate has an opening, the end of the winding extends out of the installation slot through the opening, and the potting layer partially covers and is connected to the cover plate.

[0018] In a possible embodiment of the first aspect, the potting layer extends beyond the yoke of the core or is aligned with the yoke of the core along the radial outer side of the core; and / or, the potting layer does not extend beyond the teeth of the core or is aligned with the teeth of the core along the radial inner side of the core.

[0019] In a possible implementation of the first aspect, the encapsulation layer includes: epoxy resin, silicone resin, or polyurethane resin.

[0020] In a second aspect, an embodiment of the present application provides a generator, comprising the stator described above.

[0021] In a third aspect, an embodiment of the present application provides a wind turbine generator set, comprising the generator described above.

[0022] Fourthly, an embodiment of the present application provides an anti-corona treatment method for the stator end of a generator, wherein the stator includes an iron core and a winding, wherein the iron core has a plurality of mounting slots spaced apart in its circumferential direction, and the winding is arranged on the iron core. The winding includes a plurality of branches, and each branch includes a plurality of coils. A coil is arranged in each mounting slot, and the coil has ends protruding from the iron core on both sides in the axial direction of the iron core. The anti-corona treatment method includes: selecting a coil with anti-corona compensation requirements from the multiple coils of each branch, and the working voltage of the coil with anti-corona compensation requirements is greater than the voltage anti-corona threshold when the generator operates at the rated voltage; and performing anti-corona treatment on the ends of the coil with anti-corona compensation requirements by encapsulation.

[0023] In a possible implementation manner of the fourth aspect, the voltage anti-corona threshold is less than or equal to the highest anti-corona voltage that the end of the coil can withstand based on its own anti-corona structure.

[0024] In a possible implementation manner of the fourth aspect, the voltage anti-corona threshold is greater than 20 kV.

[0025] In a possible implementation of the fourth aspect, the multiple coils of each branch are wound circumferentially along a first clockwise direction, one of the multiple coils of each branch is connected to a phase lead-out line, and the first clockwise direction includes one of a clockwise direction and a counterclockwise direction; coils with anti-corona compensation requirements are selected from the multiple coils of each branch, including: subtracting the rated voltage of the generator and the voltage anti-corona threshold to obtain a voltage width with anti-corona compensation requirements; comparing the voltage width with the voltage drop of a single-layer coil to obtain the number N of coils with anti-corona compensation requirements; for each branch, starting from the coil connected to the phase lead-out line in the branch, N consecutive coils along the first clockwise direction are determined as the coils with anti-corona compensation requirements in the branch, and N is less than the total number of coils included in the branch.

[0026] In a possible implementation of the fourth aspect, a coil with anti-corona compensation requirements is selected from multiple coils in each branch, and the method also includes: for each branch, starting from the coil connected to the phase lead wire in the branch, at least one coil along the second clockwise direction is determined as the coil with anti-corona compensation requirements in the branch, and the first clockwise direction and the second clockwise direction are arranged oppositely in the circumferential direction.

[0027] In a possible implementation manner of the fourth aspect, the voltage drop of a single-layer coil is determined by a ratio of a phase voltage of the generator to a total number of coils included in a single branch.

[0028] In a possible implementation manner of the fourth aspect, the voltage drop of a single-layer coil is determined by a ratio of a phase-to-ground voltage of the generator to a total number of coils included in a single branch.

[0029] As described above, according to the stator provided in the embodiment of the present application, at least one branch is provided with a potting layer, which covers the ends of a part of the multiple coils of the branch. The operating voltage of this part of the coils when the generator operates at the rated voltage is greater than the voltage anti-corona threshold and needs to withstand a higher voltage. The ends of the coils that withstand the higher voltage are potted for anti-corona treatment, that is, a solid insulating filling layer is introduced outside the anti-corona structure of the coil itself to eliminate the air around the coil and avoid air ionization, so that corona will not be generated at a higher voltage level.

[0030] In addition, according to the anti-corona treatment method for the stator end of the generator provided in the embodiment of the present application, there is no need to perform any treatment on the end of the low-voltage coil. Instead, it is based on the anti-corona arrangement of its own low-resistance band plus high-low resistance. This is simpler, easier and more effective, thereby reducing material usage and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present application can be better understood from the following description of the specific embodiments of the present application in conjunction with the accompanying drawings, wherein the same or similar reference numerals represent the same or similar features.

[0032] FIG1 is a schematic structural diagram of a generator stator in the related art;

[0033] FIG2 is a schematic structural diagram of the iron core shown in FIG1 ;

[0034] FIG3 is an equivalent circuit diagram of the generator stator winding;

[0035] FIG4 is a flow chart of an anti-corona treatment method for a generator stator end portion provided by one embodiment of the present application;

[0036] FIG5 is a flow chart of an anti-corona treatment method for a generator stator end portion provided by another embodiment of the present application;

[0037] FIG6 is a schematic structural diagram of a generator stator provided in an embodiment of the present application;

[0038] FIG7 is a flow chart of an anti-corona treatment method for a stator end portion of a generator provided in yet another embodiment of the present application.

[0039] Explanation of the accompanying drawings: 100 - stator; 10 - iron core; 11 - mounting slot; 20 - winding; 21 - coil; 22 (22a, 22b, 22c) - phase lead wire; 23 (23a, 23b, 23c) - potting layer; 231a - first potting part; 232a - second potting part; 24 - wire connecting line; 25 - cover plate. DETAILED DESCRIPTION

[0040] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a comprehensive understanding of the present application.

[0041] As shown in Figures 1 and 2, the stator 100 of the high-voltage generator includes an iron core 10 and a winding 20. The iron core 10 has a plurality of mounting slots 11 spaced apart along its circumference. The winding 20 is mounted on the iron core 10 and includes multiple branches, each of which includes multiple coils 21.

[0042] The winding 20 of the three-phase generator includes three branches, each corresponding to a phase. The iron core 10 shown in FIG2 has 48 mounting slots 11, so the number of coils 21 per phase and per branch is 16. A coil is disposed in each mounting slot 11, with ends protruding from the iron core 10 on both sides in the axial direction.

[0043] Since the protruding iron core 10 at the coil end is in contact with the air, the conductor part at the coil end has a higher potential, and there is electric field distortion caused by deformation, which easily generates corona. At present, the coil end of the high-voltage generator stator generally adopts an anti-corona structure with a transition between low-resistance band and high-resistance band.

[0044] However, there is an upper limit to the resistivity of the high-resistance band, and the existing anti-corona design alone cannot meet the anti-corona requirements of the generator coil ends under ultra-high voltage (27kV~35kV).

[0045] To solve the problem of anti-corona at the ends of the high-voltage generator coils, the inventors studied the equivalent circuit diagram of the stator winding (see Figure 3) and obtained the basic equation of the wind turbine:

[0046] in, are the stator voltage phasor and the rotor voltage phasor respectively; is the induced electromotive force phasor of the air gap magnetic field; are the stator current, rotor current and excitation current phasors respectively; r1 is the stator resistance; x 1σ 、x 2σ and x m They are stator leakage reactance, rotor leakage reactance and magnetizing reactance respectively; s represents slip, j is a complex number, j is positive, it means the voltage phasor leads by 90 degrees, and j is negative, it means the voltage phasor lags by 90 degrees.

[0047] It can be seen from the above formula that when the stator voltage U1 is constant, the coil group potential is proportional to the stator winding resistance r1 and the stator leakage reactance x 1σ Because the potential is related, the potential is highest at the phase lead wire location and then decreases gradually based on the coil's potential relative to ground. In other words, when the generator is operating, each coil experiences a different operating voltage: the closer it is to the phase lead wire, the higher the voltage, while the farther it is from the phase lead wire, the lower the voltage. Here, the phase lead wire refers to the lead wire for each phase of the generator.

[0048] The current mainstream anti-corona structures for high- and low-resistance bands in the industry can effectively handle and solve the problem of rated voltages up to 24kV-27kV (primarily used in hydropower, thermal power, and nuclear power). For the voltage reduction from 35kV to 24kV-27kV, the number of coils required for this voltage level can be easily calculated. For these coils, additional anti-corona treatment can be applied outside the mainstream anti-corona structure to meet the anti-corona requirements at higher voltages.

[0049] Based on this, an embodiment of the present application provides an anti-corona treatment method for the stator end of a generator, which can meet the anti-corona requirements of the coil end of a higher voltage generator.

[0050] As shown in FIG4 , the anti-corona treatment method for the stator end of a generator provided in an embodiment of the present application includes: step S1 and step S2.

[0051] S1. Select a coil with anti-corona compensation requirements from multiple coils in each branch. The operating voltage of the coil with anti-corona compensation requirements is greater than a voltage anti-corona threshold when the generator operates at rated voltage.

[0052] The voltage anti-corona threshold can be less than or equal to the maximum anti-corona voltage that the coil end can withstand based on its inherent anti-corona structure. The inherent anti-corona structure of the coil end refers to the industry's mainstream high-resistance band and low-resistance band anti-corona structures.

[0053] In the embodiment of the present application, the voltage anti-corona threshold can be obtained by actual measurement or a preset value. For example, the voltage anti-corona threshold is greater than 20V. With the increase of the resistivity of the high resistance band or the improvement of the anti-corona structure, the voltage anti-corona threshold can also be 24KV or 27KV, which is not limited here.

[0054] Since the working voltages borne by each coil are different when the generator is working, for the coils that are farther away from the phase lead-out line and bear lower working voltages, corona problems will not occur based on the anti-corona structure of the coil ends. Therefore, these coils do not need to be processed.

[0055] For coils that are closer to the phase lead wires and bear higher operating voltages, it is necessary to consider whether their operating voltage is greater than the voltage anti-corona threshold. If their operating voltage is greater than the voltage anti-corona threshold, it means that the anti-corona structure at the coil end itself cannot avoid the corona problem. Therefore, these coils require additional anti-corona treatment, and the coils with anti-corona compensation requirements need to be selected first.

[0056] S2. Perform anti-corona encapsulation treatment on the ends of the coils that require anti-corona compensation.

[0057] Through potting anti-corona treatment, a solid insulating filling layer can be introduced outside the coil's own anti-corona structure, which not only improves the resistivity of the coil's external insulation layer, but also eliminates small gaps outside the coil, completely isolating the air, thus preventing corona problems.

[0058] As described above, according to the anti-corona treatment method for the stator end of the generator provided in the embodiment of the present application, the coil with anti-corona compensation requirements is first selected from the multiple coils of each branch, that is, the coil whose operating voltage is greater than the voltage anti-corona threshold when the generator is operating at the rated voltage is selected, and then the end of this part of the coil that bears the higher voltage is sealed for anti-corona treatment, that is, a solid insulating filling layer is introduced outside the anti-corona structure of the coil itself, which can further improve the anti-corona ability of the coil.

[0059] In addition, according to the anti-corona treatment method for the stator end of the generator provided in the embodiment of the present application, there is no need to perform any treatment on the end of the coil that bears the low voltage. Instead, it is based on the anti-corona arrangement of its own low-resistance band plus high low resistance. This is simple, easy and effective, reducing material usage and reducing costs.

[0060] 5 and 6 , the anti-corona treatment method for the stator end of a generator provided in an embodiment of the present application is described in detail.

[0061] As shown in FIG5 , step S1 may include the following sub-steps S11 to S13:

[0062] S11. Subtract the rated voltage of the generator from the voltage anti-corona threshold to obtain a voltage width that meets the anti-corona compensation requirements.

[0063] S12. Compare the voltage width and the voltage drop of the single-layer coil to obtain the number N of coils that meet the anti-corona compensation requirements.

[0064] The voltage drop of a single-layer coil may be determined by the ratio of the phase voltage of the generator to the total number of coils included in a single branch, or by the ratio of the phase-to-ground voltage of the generator to the total number of coils included in a single branch.

[0065] Generally speaking, high-voltage generators used in wind power generation have more than 70 mounting slots. For example, a generator with 72 slots has 24 coils per phase and per branch. Assuming the generator's rated voltage is 35 kV, the phase-to-ground voltage is 35 / 1.732 = 20.2 kV. Therefore, the voltage drop across each coil is 20.2 / 24 = 0.84 kV. Calculated on a phase-to-phase basis, the maximum phase-to-phase voltage is 35 kV, so the voltage drop across each coil is 35 / 24 = 1.46 kV.

[0066] Taking the single-layer voltage drop of the coil obtained by relative phase calculation as a reference, assuming the voltage anti-corona threshold is 27 kV, the voltage width with anti-corona compensation requirement is calculated to be 35-27=8 kV, and the coils with anti-corona compensation requirement are 8 / 1.46=5.5 coils; assuming the voltage anti-corona threshold is 24 kV, the voltage width with anti-corona compensation requirement is calculated to be 35-24=11 kV, and the coils with anti-corona compensation requirement are 11 / 1.46=7.5 coils. To increase the safety margin, N can be taken as 8.

[0067] S13. For each branch, starting from the coil connected to the phase lead wire in the branch, N consecutive coils along the first clockwise direction are determined as the coils in the branch that have anti-corona compensation requirements, where N is less than the total number of coils included in the branch.

[0068] The multiple coils of each branch are wound circumferentially along a first clockwise direction. The first clockwise direction includes one of a clockwise direction and a counterclockwise direction. The winding direction (first clockwise direction) shown in FIG. 6 is the clockwise direction.

[0069] One of the multiple coils of each branch is connected to a phase lead wire, and FIG6 shows a phase lead wire 22a of the a-phase branch, a phase lead wire 22b of the b-phase branch, and a phase lead wire 22c of the c-phase branch.

[0070] For each branch, the potential at the phase lead-out line position is the highest. Assuming that the phase lead-out line position is the first coil of the branch, the potential decreases successively along the winding direction. Then, taking Figure 6 as an example, for the a-phase branch, the 8 coils along the clockwise direction from the phase lead-out line 22a position can be taken as coils with anti-corona compensation requirements, and then these 8 coils are potted to form a potting layer 23a; for the b-phase branch, the 8 coils along the clockwise direction from the phase lead-out line 22b position can be taken as coils with anti-corona compensation requirements, and then these 8 coils are potted to form a potting layer 23b; for the b-phase branch, the 8 coils along the clockwise direction from the phase lead-out line 22c position can be taken as coils with anti-corona compensation requirements, and then these 8 coils are potted to form a potting layer 23c.

[0071] In some optional embodiments, as shown in FIG7 , step S1 may further include sub-step S14 .

[0072] S14. For each branch, starting from the coil connected to the phase lead wire in the branch, at least one coil along the second clockwise direction is determined as the coil in the branch with anti-corona compensation requirements, and the first clockwise direction and the second clockwise direction are arranged oppositely in the circumferential direction.

[0073] In this step, the second clockwise direction can be understood as the reverse direction of winding.

[0074] Referring to Figure 6, for the a-phase branch, the electric potential at the position of the phase lead-out line 22a is the highest. For the first coil adjacent in the counterclockwise direction, although it belongs to the c-phase branch, it is easily affected by the high electric potential of the phase lead-out line 22a because it is close to the phase lead-out line 22a and is subjected to a higher voltage. Therefore, at least one coil along the opposite direction of the winding can be identified as a coil in the branch with anti-corona compensation requirements, and this part of the higher voltage coil is encapsulated, and a solid insulating filling layer is introduced outside its own anti-corona structure to further improve the anti-corona ability of this part of the coil.

[0075] In some optional embodiments, starting from the phase lead-out line position, 8 coils along the winding direction (clockwise in Figure 6) and 1 coil along the opposite winding direction (counterclockwise in Figure 6) can be potted and cast, for a total of 9 coils in a single phase. Then, the total number of coils that need to be potted and cast for the three phases is 27.

[0076] In some optional embodiments, starting from the phase lead-out line position, 8 coils along the winding direction (clockwise in Figure 6) and 2 coils along the opposite winding direction (counterclockwise in Figure 6), a total of 10 coils in a single phase, are potted and cast. Then, the total number of coils that need to be potted and cast for the three phases is 30 coils.

[0077] An embodiment of the present application further provides a stator 100, the structure of which is shown in Figure 6, comprising: an iron core 10, the iron core 10 having a plurality of mounting slots 11 spaced apart in its circumferential direction; a winding 20, arranged on the iron core 10, the winding 20 including a plurality of branches, each branch including a plurality of coils 21, each mounting slot 11 being provided with a coil 21, the coil 21 having ends protruding from the iron core 10 on both sides in the axial direction of the iron core 10; wherein, at least one branch is provided with a potting layer 23, the potting layer 23 covering the ends of a portion of the plurality of coils 21 of the branch; wherein, the operating voltage of the portion of the coils 21 when the generator operates at the rated voltage is greater than the voltage anti-corona threshold.

[0078] In some optional embodiments, the partial number of coils includes N consecutive coils along a first clockwise direction, starting from the coil connected to the phase lead wire in the branch; wherein the first clockwise direction includes one of a clockwise direction and a counterclockwise direction, N is determined by the ratio of the voltage width with anti-corona compensation requirements to the voltage drop of a single-layer coil, and N is less than the total number of coils included in the branch.

[0079] In some optional embodiments, the voltage width with the anti-corona compensation requirement is obtained by subtracting the rated voltage of the generator from the voltage anti-corona threshold.

[0080] In some optional embodiments, each branch is provided with a potting layer 23 .

[0081] In some optional embodiments, the multiple coils of each branch are wound circumferentially along a first clockwise direction, and one of the multiple coils of each branch is connected to a phase lead wire; the potting layer 23 corresponding to each branch includes a first potting portion 231a, and the first potting portion 231a starts from the coil in the branch connected to the phase lead wire, and continuously covers N coils along the first clockwise direction, where N is less than the total number of coils included in the branch, and the first clockwise direction includes one of a clockwise direction and a counterclockwise direction.

[0082] In some optional embodiments, the potting layer 23 corresponding to each branch also includes a second potting portion 232a, which starts from a coil connected to a phase lead wire in the branch and covers at least one coil along a second clockwise direction, and the first clockwise direction and the second clockwise direction are arranged oppositely in the circumferential direction.

[0083] In some optional embodiments, a wire connection line 24 is provided at one end of the coil, the coils in the same branch are connected via the wire connection line 24 , and the wire connection line 24 is potted and covered.

[0084] In some optional embodiments, a cover plate is provided at the outlet of the mounting groove 11 , and the cover plate has an opening, through which the end of the winding 20 extends out of the mounting groove 11 , and the potting layer 23 partially covers the cover plate 25 and is connected to the cover plate 25 .

[0085] In some optional embodiments, the encapsulation layer 23 extends beyond the yoke of the core 10 along the radial outer side of the core 10 or is aligned with the yoke of the core 10; and / or, the encapsulation layer 23 does not extend beyond the teeth of the core 10 along the radial inner side of the core 10 or is aligned with the teeth of the core 10.

[0086] The resin used for potting may include silicone resin, epoxy resin, polyurethane resin and the like.

[0087] Common potting methods for generator ends mainly include end port potting and end overall potting.

[0088] The location of the end port potting is a small part behind the core slot, within a height range of about 10mm-50mm.

[0089] The end integral potting position is along the axial end integral. For example, some submarine motors, nuclear submarine motors, ship motors, underwater or submarine motors all have sealing requirements, and generally they are cast or potted for sealing.

[0090] Different from the end port potting and the end overall potting, this application is a segmented potting along the circumference of the stator end, mainly for the coils that are subjected to higher voltages in generators with higher voltage levels, such as 24kv~27kV and above, or even generators above 35kV. Wind turbines are generally in the range of 1MW-20MW, and single-unit capacity units of more than 20MW may be developed in the future.

[0091] The benefits of this segmented potting include:

[0092] (1) The coils at higher voltage positions exceeding the voltage anti-corona threshold are encapsulated to prevent corona, which will not generate corona. For voltage levels below this level, the current mature method is adopted, that is, the arrangement of high and low resistance band anti-corona layers. This will be simple, easy and effective, reduce material consumption and reduce costs;

[0093] (2) If all the ends are potted, the amount of potting resin used at the two ends of a stator with an outer diameter of 2 meters is expected to exceed 1 ton. The entire generator is generally only around 15-18 tons, which is almost 5%-7% of the weight value. After segmented potting, the potting area only accounts for 37.5% of the original weight, so the weight can be reduced, which is expected to be less than 0.4 tons. Then the potting weight will drop to within 2%-3% of the total weight of the generator, which is beneficial to the load design of the whole machine.

[0094] (3) If all ends are potted, cooling of the ends will be difficult and ventilation will be insufficient, resulting in severe heating of the ends and a high temperature rise of the entire generator. Alternatively, the copper density needs to be very low. The gas heat exchange efficiency is much higher than that of organic materials. Therefore, segmented potting can also better dissipate the heat of the generator, thereby improving the heat dissipation capacity. The present application also provides a generator comprising a stator as described above.

[0095] An embodiment of the present application further provides a wind turbine generator set, comprising the generator described above.

[0096] It should be understood that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. For the device embodiment, the relevant parts can refer to the description part of the method embodiment. The embodiments of the present application are not limited to the specific steps and structures described above and shown in the figures. Those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the embodiments of the present application. In addition, for the sake of brevity, a detailed description of known method technologies is omitted here.

[0097] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in unit, a function card, etc. When implemented in software, the elements of the embodiments of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0098] The embodiments of the present application can be implemented in other specific forms without departing from its spirit and essential characteristics. For example, the algorithm described in the specific embodiment can be modified, and the system architecture does not depart from the basic spirit of the embodiments of the present application. Therefore, the current embodiment is considered to be exemplary and non-restrictive in all aspects, and the scope of the embodiments of the present application is defined by the appended claims rather than the above description, and all changes within the scope of the meaning and equivalents of the claims are included in the scope of the embodiments of the present application.

Claims

1. A stator (100), comprising: An iron core (10), wherein the iron core (10) has a plurality of installation grooves (11) spaced apart in the circumferential direction thereof; A winding (20) is arranged on the iron core (10), the winding comprises a plurality of branches, each of the branches comprises a plurality of coils (21), each of the mounting grooves (11) is provided with a coil (21), and the coil (21) has ends protruding from the iron core (10) on both sides in the axial direction of the iron core (10); Wherein, at least one of the branches is provided with a potting layer (23), and the potting layer (23) covers the ends of a portion of the coils (21) among the plurality of coils (21) of the branch; Wherein, the operating voltage of the partial number of coils (21) when the generator operates at a rated voltage is greater than a voltage anti-corona threshold.

2. The stator (100) according to claim 1, wherein: The voltage anti-corona threshold is less than or equal to the maximum anti-corona voltage that the end of the coil (21) can withstand based on its own anti-corona structure.

3. The stator (100) according to claim 1, wherein: The voltage anti-corona threshold is greater than 20KV.

4. The stator (100) according to claim 1, wherein: For any of the branches, the partial number of coils (21) include N coils that are continuous along a first clockwise direction, starting from the coil connected to the phase lead wire in the branch; The first clockwise direction includes one of a clockwise direction and a counterclockwise direction, and N is determined by the ratio of a voltage width with anti-corona compensation requirements to a voltage drop of a single-layer coil, and N is less than the total number of coils included in the branch.

5. The stator (100) according to claim 4, wherein: The voltage width with the anti-corona compensation requirement is obtained by subtracting the rated voltage of the generator from the voltage anti-corona threshold.

6. The stator (100) according to claim 1, wherein: Each of the branches is provided with the potting layer (23).

7. The stator (100) according to claim 1, wherein: The plurality of coils (21) of each branch are wound in the circumferential direction along a first clockwise direction, and one of the plurality of coils (21) of each branch is connected to a phase lead wire (22); The potting layer (23) corresponding to each branch comprises a first potting portion (231a), the first potting portion (231a) starting from the coil (21) connected to the phase lead wire (22) in the branch, and continuously covering N coils (21) along the first clockwise direction, N being less than the total number of coils (21) included in the branch, and the first clockwise direction comprising one of a clockwise direction and a counterclockwise direction.

8. The stator (100) according to claim 7, wherein: The potting layer (23) corresponding to each branch further comprises a second potting portion (232a), the second potting portion (232a) starting from a coil (21) connected to the phase lead wire (22) in the branch, and covering at least one coil (21) along a second clockwise direction, the first clockwise direction and the second clockwise direction being arranged opposite to each other in the circumferential direction.

9. The stator (100) according to claim 1, wherein: A wire connection line (24) is provided at one end of the coil (21), the coils (21) in the same branch are connected via the wire connection line (24), and the potting layer (23) covers the wire connection line (24).

10. The stator (100) according to claim 1, wherein: A cover plate (25) is provided at the outlet of the installation groove (11), the cover plate (25) having an opening, the end of the winding protruding out of the installation groove (11) through the opening, and the potting layer (23) partially covers the cover plate (25) and is connected to the cover plate (25).

11. The stator (100) according to claim 1, wherein: The potting layer (23) extends beyond the yoke of the iron core (10) along the radial outer side of the iron core (10) or is aligned with the yoke of the iron core (10); and / or, The potting layer (23) does not extend beyond the tooth portion of the iron core (10) along the radial inner side of the iron core (10) or is aligned with the tooth portion of the iron core (10).

12. The stator (100) according to claim 1, wherein: The potting layer (23) comprises: epoxy resin, silicone resin or polyurethane resin.

13. A generator, comprising the stator (100) according to any one of claims 1 to 12.

14. A wind turbine generator set comprising the generator according to claim 13.

15. A method for treating an end of a generator stator against corona, the stator (100) comprising an iron core (10) and a winding (20), the iron core (10) being provided with a plurality of mounting grooves (11) spaced apart in its circumferential direction, the winding (20) being arranged on the iron core (10), the winding (20) comprising a plurality of branches, each of the branches comprising a plurality of coils (21), each of the mounting grooves (11) being provided with the coil (21), the coil (21) having ends protruding from the iron core (10) on both sides in the axial direction of the iron core (10), the method for treating the stator against corona comprising: Selecting a coil with anti-corona compensation requirement from a plurality of coils in each branch, wherein the working voltage of the coil with anti-corona compensation requirement is greater than a voltage anti-corona threshold when the generator operates at a rated voltage; The end of the coil with anti-corona compensation requirements is subjected to potting anti-corona treatment.

16. The anti-corona treatment method according to claim 15, wherein: The voltage anti-corona threshold is less than or equal to the highest anti-corona voltage that the end of the coil can withstand based on its own anti-corona structure.

17. The anti-corona treatment method according to claim 15, wherein: The voltage anti-corona threshold is greater than 20KV.

18. The anti-corona treatment method according to claim 15, wherein: The plurality of coils of each branch are wound along a first clockwise direction in the circumferential direction, one of the plurality of coils of each branch is connected to a phase lead wire, and the first clockwise direction includes one of a clockwise direction and a counterclockwise direction; The step of selecting a coil having an anti-corona compensation requirement from a plurality of coils in each branch includes: Subtracting the rated voltage of the generator from the voltage anti-corona threshold to obtain a voltage width with anti-corona compensation requirements; Comparing the voltage width with the voltage drop of a single-layer coil, the number N of coils with anti-corona compensation requirements is obtained; For each of the branches, starting from the coil connected to the phase lead wire in the branch, the N consecutive coils along the first clockwise direction are determined as the coils in the branch with anti-corona compensation requirements, and N is less than the total number of coils included in the branch.

19. The anti-corona treatment method according to claim 18, wherein: The step of selecting a coil having an anti-corona compensation requirement from a plurality of coils in each branch circuit further comprises: For each branch, starting from the coil connected to the phase lead wire in the branch, at least one coil along the second clockwise direction is determined as the coil with anti-corona compensation requirements in the branch, and the first clockwise direction and the second clockwise direction are opposite in the circumferential direction. Anti-settings.

20. The anti-corona treatment method according to claim 18, wherein: The voltage drop of the single-layer coil is determined by the ratio of the phase voltage of the generator to the total number of coils included in a single branch, or the ratio of the phase-to-ground voltage of the generator to the total number of coils included in a single branch.

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