阅读说明：本技术 一种定子绕组相间电晕情况的修复方法 (Method for repairing stator winding interphase corona condition ) 是由 孙永鑫 范寿孝 满宇光 魏丽华 索春英 于 2021-10-11 设计创作，主要内容包括：本发明公开一种定子绕组相间电晕情况的修复方法。本发明使用室温涂刷胶和填料相混合的方式,对定子绕组相间绝缘垫块位置进行精确修复,能够有效改善绕组相间绝缘形状,提高定子绕组的起晕电压水平。本发明具有结构简单、工艺方便、修复快速和效果显著的优点,能够有效消除定子绕组相间绝缘垫块附近的电晕放电情况,避免电晕放电对定子线棒主绝缘的腐蚀,提高定子绕组的电气性能稳定性,延长定子绕组的使用寿命。(The invention discloses a method for repairing the interphase corona condition of a stator winding. The invention uses the mixing mode of room temperature coating glue and filler to accurately repair the position of the stator winding interphase insulation cushion block, can effectively improve the winding interphase insulation shape, and improves the corona onset voltage level of the stator winding. The invention has the advantages of simple structure, convenient process, quick repair and obvious effect, can effectively eliminate the condition of corona discharge near the interphase insulating cushion block of the stator winding, avoids the corrosion of the corona discharge to the main insulation of the stator bar, improves the electrical performance stability of the stator winding and prolongs the service life of the stator winding.)

1. A method for repairing the condition of corona between phases of stator windings is characterized by comprising the following steps:

the method comprises the following steps: the repair material for the stator winding interphase corona condition comprises a two-component room-temperature solvent-free coating adhesive, 250-mesh quartz powder, 95% industrial alcohol and epoxy ester air-drying red enamel, wherein the initial mixing viscosity of the two-component room-temperature solvent-free coating adhesive at 25 ℃ is 500-800 mPa & s, the pot life is more than or equal to 30min, the curing time is less than or equal to 24h, the dielectric strength is more than or equal to 20kV/mm, the paint film drying time of the epoxy ester air-drying red enamel is less than or equal to 24h, and the dielectric strength is more than or equal to 30 kV/mm;

step two: at stator winding interphase positions (1), grinding an intersection right angle (4) of an insulating cushion block (2) and a stator bar (3) by 600-mesh abrasive paper along the wide surface direction of the bar, removing sharp-angle burrs and stains, wiping the ground part by using silk cloth dipped with alcohol, and drying;

step three: coating the double-component room-temperature solvent-free glue and 250-mesh quartz powder according to the weight ratio of 1: 0.5, fully kneading and mixing, adjusting the mixing proportion when the mixed putty (5) is placed naturally without deformation and fingers can deform slightly;

step four: filling a crossed right angle part (4) of an insulating cushion block (2) at the end part of a stator winding and a stator bar (3) by using mixed putty (5) within half an hour after mixing, filling the mixed right angle part in the wide surface direction of the line bar in a full-length manner, cleaning the redundant mixed putty (5) after filling by using alcohol, repeatedly rubbing the cylindrical glass bar by using a special repairing tool for at least ten times along a repairing position, and ensuring that the radius R of an inner fillet at the position is more than or equal to 5mm after the filling is finished and the radius of fillets at other transition positions is more than or equal to 2 mm;

step five: after curing for 24h at normal temperature, polishing and shaping the filling part of the mixed putty (5) by 600-mesh sand paper to ensure smooth transition of all fillets;

step six: after finishing shaping, wiping the polished part with alcohol by silk cloth, drying, spraying a layer of epoxy resin, drying the red enamel paint, and drying the enamel paint.

2. The method for repairing the stator winding interphase corona condition according to claim 1, characterized by comprising the following steps: in the fourth step, the special repairing tool for the stator winding interphase corona is a cylindrical glass rod with the length of 25cm and the radius of 5 mm.

3. The method for repairing the stator winding interphase corona condition according to claim 1, characterized by comprising the following steps: in the sixth step, the red enamel paint film is required to ensure that the sprayed part is comprehensive and uniform in thickness, and flowing marks and paint lumps cannot be generated.

4. The method for repairing the stator winding interphase corona condition according to claim 1, characterized by comprising the following steps: and in the sixth step, the epoxy resin air-dried red enamel is cured at normal temperature for not less than 3 hours.

Technical Field

The invention relates to the field of high-voltage motors, in particular to a method for repairing the interphase corona condition of a stator winding.

Background

The high-voltage motor stator winding interphase corona discharge is a common corona problem in tests and operation. The long-term corona discharge continuously corrodes the stator winding, and a winding short circuit accident is caused in serious cases, so the corona discharge condition of the stator winding is repaired, and the corona discharge repairing method plays an important role in stable operation of the stator winding of the high-voltage motor.

The insulation structure of the end part of the stator winding is complex, and matched insulation structures such as cushion blocks, binding ropes, end hoops and the like exist. At the interface position of different insulation structures, due to the influence of the insulation structure, material physical properties and external air gap shape, high electric field intensity is easily generated at the interface position, and a corona discharge phenomenon is caused. An air gap exists at the junction position of the insulating cushion blocks among the stator winding phases and the stator bar, the distance is small, and the corona discharge condition of the stator winding is easy to generate at the junction position. Therefore, how to establish a reasonable insulation structure and an anti-corona structure plays an important role in improving the corona voltage level of the stator winding.

Meanwhile, the running environment of the stator winding is severe and is in a high electric, thermal and mechanical stress environment, so that the stator winding is difficult to disassemble and repair after being installed, and the problem that the stator winding is difficult to repair, such as corona and the like, is caused. How to effectively restore the corona condition of the stator winding in a reasonable mode and improve the corona voltage level of the winding is a technical problem which puzzles high-voltage motor insulation design and electrical operation and maintenance personnel.

Disclosure of Invention

In view of the above, the invention aims to develop a repairing method for improving the interphase corona condition of a stator winding of a high-voltage motor, which has the advantages of simple structure, convenient process, quick repairing and obvious effect, can effectively eliminate the corona discharge condition near an interphase insulating cushion block of the stator winding, avoid the corrosion of the corona discharge to the main insulation of a stator bar, improve the electrical performance stability of the stator winding, and prolong the service life of the stator winding. The technical scheme of the invention comprises the following steps:

the method comprises the following steps: the repair material for the stator winding interphase corona condition comprises a two-component room-temperature solvent-free brushing adhesive, 250-mesh quartz powder, 95% industrial alcohol and epoxy ester air-drying red enamel, wherein the initial mixing viscosity (25 ℃) of the two-component room-temperature solvent-free brushing adhesive is 500-800 mPa & s, the pot life is more than or equal to 30min, the curing time is less than or equal to 24h, the dielectric strength is more than or equal to 20kV/mm, the paint film drying time of the epoxy ester air-drying red enamel is less than or equal to 24h, and the dielectric strength is more than or equal to 30 kV/mm;

step two: at stator winding alternate positions, polishing orthogonal corners of the insulating cushion blocks and the stator wire bars by 600-mesh abrasive paper along the wide surface direction of the wire bars, removing sharp-corner burrs and stains, wiping the polished positions by using silk cloth dipped with alcohol, and airing;

step three: coating the double-component room-temperature solvent-free glue and 250-mesh quartz powder according to the weight ratio of 1: 0.5, fully rubbing and mixing, and adjusting the mixing proportion until the mixed putty is naturally placed and does not deform and fingers can deform slightly;

step four: filling the crossed right angle between the insulating cushion block at the end part of the stator winding and the stator wire rod by using mixed putty within half an hour after mixing, filling the mixed putty in the wide surface direction of the wire rod in a full-length manner, cleaning the redundant mixed putty after filling by using alcohol, using a special repairing tool as a cylindrical glass rod with the length of 25cm and the radius of 5mm, repeatedly rubbing the cylindrical glass rod for at least ten times along a repairing position, and ensuring that the radius R of an inner fillet at the position is more than or equal to 5mm after filling, and the radius of fillets at other transition positions is more than or equal to 2 mm;

step five: after curing for 24h at normal temperature, polishing and shaping the filling part of the mixed putty by 600-mesh abrasive paper to ensure smooth transition of each fillet, wiping and drying the polished part by dipping alcohol on silk cloth, spraying a layer of epoxy resin to dry red enamel, and curing at normal temperature for not less than 3 h.

Step six: after finishing shaping, wiping the polished part with alcohol by silk cloth, drying, spraying a layer of epoxy resin, drying the red enamel paint, and drying the enamel paint.

In the fourth step, the special repairing tool for the stator winding interphase corona is a cylindrical glass rod with the length of 25cm and the radius of 5 mm.

In the sixth step, the red enamel paint film is required to ensure that the sprayed part is complete and uniform in thickness, and flowing marks and paint lumps cannot be generated.

In the sixth step, the normal-temperature curing of the epoxy resin air-dried red enamel paint is not less than 3 hours.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method for repairing the interphase corona condition of a stator winding, which can achieve the following technical effects through the innovative method:

1. the level of the corona onset voltage of the stator winding is increased. The intersection right angle position of the insulating cushion block and the stator bar is one of common stator winding corona discharge positions, and the fillet radius at the position is increased by filling mixed putty at the position, so that the electric field intensity at the position can be greatly reduced, and the corona starting voltage level of the stator winding is improved;

2. the corona repair operation of the stator winding is convenient to carry out. After the stator winding of the high-voltage motor is installed, the operations such as disassembly, surface layer process treatment and the like are very difficult, the method can effectively repair the corona discharge of the stator winding in a mode of adding an insulating material, and the process is convenient and quick;

3. the service life of the stator winding is prolonged. The mixed putty is used for repairing the corona defect of the winding, so that the corona discharge condition of the stator winding during operation can be reduced, the corona discharge quantity of the winding is reduced, the operation stability of the stator winding is improved, and the service life of the stator winding is prolonged.

Drawings

FIG. 1 is a schematic diagram of a method for improving the interphase corona repair of stator windings.

The notation in the figure is: 1-stator winding interphase position, 2-insulating cushion block, 3-stator bar, 4-phase intersection right angle position and 5-mixed putty.

Detailed Description

The present application is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present application is not limited thereby.

The invention relates to a method for repairing the interphase corona condition of a stator winding, which comprises the following steps:

the method comprises the following steps: the repair material for the stator winding interphase corona condition comprises a two-component room-temperature solvent-free brushing adhesive, 250-mesh quartz powder, 95% industrial alcohol and epoxy ester air-drying red enamel, wherein the initial mixing viscosity (25 ℃) of the two-component room-temperature solvent-free brushing adhesive is 500-800 mPa & s, the pot life is more than or equal to 30min, the curing time is less than or equal to 24h, the dielectric strength is more than or equal to 20kV/mm, the paint film drying time of the epoxy ester air-drying red enamel is less than or equal to 24h, and the dielectric strength is more than or equal to 30 kV/mm;

step two: as shown in fig. 1, at stator winding interphase positions 1, grinding orthogonal corners 4 of insulating pads 2 and stator bars 3 by 600-mesh sand paper along the wide surface direction of the bars to remove sharp-corner burrs and stains, wiping the ground parts by using silk cloth dipped with alcohol, and drying the parts by airing, wherein the emphasis is placed on clearing away scraps and checking the grinding effect; the purpose of this step is to guarantee that the juncture of stator winding 1 and insulating pad 2 is smooth in transition and free from impurity.

Step three: coating the double-component room-temperature solvent-free glue and 250-mesh quartz powder, and kneading by hands and rolling a rolling pin according to the weight ratio of 1: 0.5, fully rubbing and mixing, and adjusting the mixing proportion until the mixed putty 5 is naturally placed and does not deform and fingers can deform slightly; the mixed putty 5 prepared by the step has certain conformality and no fluidity, can ensure a certain shape after being filled, and does not deform in the curing process.

Step four: as shown in figure 1, within a half hour after mixing, filling a right angle 4 at which an insulating cushion block 2 at the end part of a stator winding and a stator bar 3 are intersected by using mixed putty 5, filling the straight angle along the wide surface direction of the line bar in a full-length manner, cleaning the redundant mixed putty 5 after filling by using alcohol, using a special repairing tool as a cylindrical glass bar with the length of 25cm and the radius of 5mm, repeatedly rubbing the repairing position for at least ten times, ensuring that the radius R of an inner fillet at the position is more than or equal to 5mm after filling, and the radius of fillets at other transition positions is more than or equal to 2mm, and paying attention to the transition condition of the upper surface and the lower surface of the filling position; the purpose of using the glass rod in the step is to smooth and conveniently clean the surface, and the adhesion between the glass rod body and the mixed putty 5 is lower and easy to operate.

Step five: after curing for 24h at normal temperature, polishing and shaping the filling part of the mixed putty 5 by 600-mesh abrasive paper to ensure smooth transition of each fillet, wiping and drying the polished part by dipping alcohol in silk cloth, spraying a layer of epoxy resin and drying red porcelain paint, wherein a paint film ensures that the sprayed part is comprehensive and uniform in thickness and does not generate flowing marks or paint nodules, and the curing is not less than 3h at normal temperature; the purpose of the step that the flowing trace and the paint bump cannot be generated is to avoid the influence on the winding corona discharge level caused by the fact that the corner field intensity is too high.

Furthermore, in the fourth step, the special repairing tool for the stator winding interphase corona is a cylindrical glass rod with the length of 25cm and the radius of 5 mm.

Further, in the sixth step, the red enamel paint film is required to ensure that the sprayed part is complete and uniform in thickness, and flowing marks and paint lumps cannot be generated.

Further, in the sixth step, the epoxy resin air-dried red enamel is cured for not less than 3 hours at normal temperature. .

Although the description may refer to embodiments, not every embodiment may contain a single embodiment, and such description is for clarity only and will be understood by those skilled in the art: the technical solutions in the embodiments may be combined to form other embodiments as will be understood by those skilled in the art, taking the description as a whole.