A method for detecting anti-corona defects of stator wire bars of high-voltage motors

Abstract

The present invention discloses a method for detecting anti-corona defects of stator wire rods of high-voltage motors, and relates to the technical field of electrical component detection methods, including a method for detecting anti-corona defects of stator wire rod slots and a method for detecting anti-corona defects of stator wire rod ends. A high-frequency pulse test power supply is applied to the stator wire rod, and the rapidly increasing capacitive current makes the charge energy at the anti-corona defect of the stator wire rod large, the discharge energy high, and the discharge fast. The temperature change and discharge of the anti-corona layer on the surface of the stator wire rod can be clearly observed by visual or infrared thermal imaging, and the efficiency is relatively high; and the temperature change of the inner anti-corona layer of the stator wire rod can also be observed by infrared thermal imaging. It is judged whether there is an anti-corona defect in the overlap area of ​​the inner anti-corona layer of the stator wire rod through the temperature change, and there is no need to wait until the anti-corona defect of the inner anti-corona layer is exposed after the motor has been running for a long time before knowing it, and it can be discovered, repaired or replaced in time.

Description

Technical Field

[0001] The invention relates to the technical field of electrical component detection methods, and in particular to a method for detecting anti-corona defects of a stator wire bar of a high-voltage motor. Background Art

[0002] The stator bar is one of the main components of the high-voltage motor, which is equipped with an anti-corona layer to ensure the safe and stable operation of the motor. When there are anti-corona defects such as damage to the low-resistance anti-corona layer in the overlap area of ​​the stator bar anti-corona layer, uneven application of the low-resistance anti-corona paint, poor overlap between the high-resistance anti-corona layer and the low-resistance anti-corona layer, and hollow overlap, the anti-corona in the slot area of ​​the stator bar is prone to electrical corrosion during the operation of the motor, affecting the safe and stable operation of the motor.

[0003] like Figure 1 As shown, the conventional anti-corona structure of the stator wire bar of a high-voltage motor. The anti-corona layer structure of the stator wire bar is mainly composed of an inner low-resistance anti-corona belt, a first inner high-resistance anti-corona belt, a second inner high-resistance anti-corona belt, a third inner high-resistance anti-corona belt, an end anti-corona protective layer, an outer low-resistance anti-corona paint, and an outer high-resistance anti-corona paint, forming an outer high- and low-resistance anti-corona paint overlap area at the notch, an inner high- and low-resistance anti-corona belt overlap area at the notch, an inner high- and low-resistance anti-corona belt overlap area at the first end, and an inner high-resistance anti-corona belt overlap area at the second end.

[0004] The conventional detection method for the anti-corona performance of high-voltage motor stator wire rods is: apply a sinusoidal power frequency voltage of 1.5 times the rated voltage of the corresponding motor to the stator wire rod, and use visual or ultraviolet imaging equipment under darkroom conditions to detect the corona discharge on the surface of the stator wire rod to determine whether there are anti-corona defects in the anti-corona layer. The ultraviolet imaging equipment needs to observe the discharge of the stator wire rod in all directions at 360°, and the efficiency is relatively low. In addition, the stator wire rod under the power frequency voltage has small charge energy, low discharge energy, and slow discharge. Therefore, the conventional detection method can only detect whether there are obvious anti-corona defects on the surface of the stator wire rod, that is, Figure 1 Whether there are obvious anti-corona defects in the overlapping area of ​​high and low resistance anti-corona paints on the outer layer of the slot, and whether there are local tiny anti-corona defects on the surface of the stator wire bar, such as uneven application of low resistance anti-corona paint, leakage points, insufficient overlap, etc., sensitive ultraviolet imaging equipment cannot detect weak discharge phenomena; for the anti-corona defects in the inner layer of the stator wire bar, that is, the anti-corona defects in the overlapping area of ​​high and low resistance anti-corona bands in the inner layer of the slot and the overlapping area of ​​the inner layer high resistance anti-corona band, conventional detection methods cannot detect them. Only after the motor has been running for a long time can the anti-corona defects in the inner anti-corona layer be exposed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting anti-corona defects of stator wire bars of high-voltage motors, which uses a high-frequency pulse test power supply instead of a sinusoidal industrial frequency voltage and an infrared thermal imager instead of an ultraviolet imaging device to clearly detect whether there are anti-corona defects on the surface of the stator wire bars and whether there are anti-corona defects in the inner layer of the stator wire bars in order to solve the above-mentioned problems.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for detecting anti-corona defects of a stator wire bar of a high-voltage motor, including a stator wire bar slot outlet anti-corona defect detection method, used to detect whether there is an anti-corona defect at the slot outlet of the stator wire bar anti-corona layer, the stator wire bar anti-corona layer slot outlet includes an outer layer high- and low-resistance anti-corona paint overlap area of ​​the slot outlet, and an inner layer high- and low-resistance anti-corona belt overlap area of ​​the slot outlet;

[0008] The stator bar slot anti-corona defect detection method comprises the following steps:

[0009] SA1. Apply high-frequency pulse test power to the stator bars;

[0010] SA21. Use visual observation or infrared thermal imaging to observe the temperature and discharge of the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch. If there is a sudden temperature change or discharge in this area, the location of the sudden temperature change is determined to be the location of the anti-corona defect on the outer layer of the notch; if there is no obvious increase in temperature or discharge in this area, it is determined that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch;

[0011] SA22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch. If a sudden temperature change occurs in this area, the location of the sudden temperature change is determined to be the location of the anti-corona defect in the inner layer of the notch. If the temperature in this area does not increase significantly, it is determined that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch.

[0012] Preferably, it also includes a stator wire rod end anti-corona defect detection method for detecting whether there is an anti-corona defect in the stator wire rod end anti-corona layer, the stator wire rod end anti-corona layer comprising a first end inner layer high-resistance anti-corona belt overlap region and a second end inner layer high-resistance anti-corona belt overlap region;

[0013] The stator bar end anti-corona defect detection method comprises the following steps:

[0014] SB1. Apply high-frequency pulse test power to the stator bars;

[0015] SB21. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner layer high-resistance anti-corona belt of the first end. If a sudden temperature change occurs in this area, the location of the sudden temperature change is determined to be the location of the anti-corona defect of the inner layer of the first end. If the temperature of this area does not increase significantly, it is determined that there is no anti-corona defect in the overlapping area of ​​the inner layer high-resistance anti-corona belt of the first end.

[0016] SB22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner high-resistance anti-corona belt of the second end. If a sudden temperature change occurs in this area, the location of the sudden temperature change is determined to be the location of the anti-corona defect in the inner layer of the second end. If the temperature in this area does not show a significant increase, it is determined that there is no anti-corona defect in the overlapping area of ​​the inner high-resistance anti-corona belt of the second end.

[0017] Preferably, the peak-to-peak value of the voltage of the high-frequency pulse test power supply in step SA1 and / or step SB1 is 1.0 to 1.1 times the rated voltage value of the motor corresponding to the stator bar, and the voltage is maintained for 2 to 3 minutes.

[0018] Preferably, the output waveform of the high-frequency pulse test power supply in step SA1 and / or step SB1 is a square wave, and the impulse rise time is less than 2 μs.

[0019] Preferably, the repetition rate of the high-frequency pulse test power supply impulse voltage in step SA1 and / or step SB1 is 8 to 20 kHz.

[0020] Preferably, step SA1 and / or step SB1 are performed at room temperature after the anti-corona layer of the stator wire bar is cured.

[0021] Preferably, in step SA21, after the position of the anti-corona defect in the outer layer of the notch is determined, the position is repaired and steps SA1 and SA21 are repeated.

[0022] Preferably, in step SA22, after the position of the anti-corona defect in the inner layer of the notch is determined, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

[0023] Preferably, in step SB21, after determining the position of the anti-corona defect in the inner layer of the first end, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

[0024] Preferably, in step SB22, after determining the position of the anti-corona defect in the inner layer of the second end, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

[0025] In summary, due to the adoption of the above-mentioned technical scheme, the beneficial effects of the present invention are: a high-frequency pulse test power supply is applied to the stator wire bar, and the rapidly increasing capacitive current makes the charge energy at the anti-corona defect of the stator wire bar large, the discharge energy high, and the discharge fast. The temperature change and discharge of the anti-corona layer on the surface of the stator wire bar can be clearly observed by visual or infrared thermal imaging, and the efficiency is relatively high; and the temperature change of the inner anti-corona layer of the stator wire bar can also be observed by infrared thermal imaging. The temperature change can be used to judge whether there is an anti-corona defect in the overlapping area of ​​the inner anti-corona layer of the stator wire bar. There is no need to wait until the anti-corona defect of the inner anti-corona layer is exposed after the motor has been running for a long time, and it can be discovered, repaired or replaced in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the anti-corona layer for stator wire bars.

[0027] Figure 2 The figure is a flow chart of the anti-corona defect detection method for stator wire bar slots.

[0028] Figure 3 The figure is a flow chart of the anti-corona defect detection method for the stator wire bar end.

[0029] Markings in the figure: stator wire rod -9, inner layer low resistance anti-corona band -91, first inner layer high resistance anti-corona band -92, second inner layer high resistance anti-corona band -93, third inner layer high resistance anti-corona band -94, wire rod end anti-corona protection layer -95, outer layer low resistance anti-corona paint -96, outer layer high resistance anti-corona paint -97. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] A method for detecting anti-corona defects of stator wire rods of high-voltage motors includes a method for detecting anti-corona defects of stator wire rod slots and a method for detecting anti-corona defects of stator wire rod ends. The method for detecting anti-corona defects of stator wire rod slots is aimed at the anti-corona defects of the slot region of the stator wire rod 9. Since the electrical stress concentration and high heat loss in the slot region are high, anti-corona defects of the anti-corona layer are prone to occur. Therefore, this detection method is a commonly used detection method, which is used to detect whether there are anti-corona defects at the slot of the anti-corona layer of the stator wire rod 9; the slot of the anti-corona layer of the stator wire rod 9 includes the overlapping area of ​​the high- and low-resistance anti-corona paint of the outer layer of the slot, and the overlapping area of ​​the high- and low-resistance anti-corona tape of the inner layer of the slot. The method for detecting anti-corona defects of stator wire rod ends is used to detect whether there are anti-corona defects in the anti-corona layer of the stator wire rod 9 ends; the anti-corona layer of the stator wire rod 9 ends includes the overlapping area of ​​the high-resistance anti-corona tape of the inner layer of the first end, and the overlapping area of ​​the high-resistance anti-corona tape of the inner layer of the second end.

[0033] like Figure 1 As shown, the anti-corona layer of the stator wire rod 9 includes an inner low-resistance anti-corona band 91, a first inner high-resistance anti-corona band 92, a second inner high-resistance anti-corona band 93, a third inner high-resistance anti-corona band 94, an anti-corona protection layer 95 at the wire rod end, an outer low-resistance anti-corona paint 96, and an outer high-resistance anti-corona paint 97. The overlapping area of ​​the outer high- and low-resistance anti-corona paint at the slot outlet is the overlapping area of ​​the outer low-resistance anti-corona paint 96 and the outer high-resistance anti-corona paint 97, the overlapping area of ​​the inner high- and low-resistance anti-corona bands at the slot outlet is the overlapping area of ​​the inner low-resistance anti-corona band 91 and the first inner high-resistance anti-corona band 92, the overlapping area of ​​the inner high-resistance anti-corona band at the first end is the overlapping area of ​​the first inner high-resistance anti-corona band 92 and the second inner high-resistance anti-corona band 93, and the overlapping area of ​​the inner high-resistance anti-corona band at the second end is the overlapping area of ​​the second inner high-resistance anti-corona band 93 and the third inner high-resistance anti-corona band 94.

[0034] Please see Figure 2 The stator bar slot anti-corona defect detection method comprises the following steps:

[0035] SA1. After the anti-corona layer of the stator wire bar 9 is cured, a high-frequency pulse test power supply is applied to the stator wire bar 9 at room temperature. The peak-to-peak value of the voltage is 1.0 to 1.1 times the rated voltage value of the motor corresponding to the stator wire bar 9. The voltage is maintained for 2 to 3 minutes. The output waveform of the high-frequency pulse test power supply is a square wave, the impulse rise time is less than 2μs, and the impulse voltage repetition rate is 8 to 20kHz.

[0036] SA21. Use visual or infrared thermal imager to observe the temperature and discharge of the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch. If a sudden temperature change or discharge occurs in this area, determine the location of the sudden temperature change as the anti-corona defect location of the outer layer of the notch, repair this location, and repeat steps SA1 and SA21. If there is no obvious increase or discharge in the temperature of this area, determine that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona belts on the outer layer of the notch. The anti-corona defects in the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch are poor overlap, missing spots and uneven painting.

[0037] SA22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the slot. If there is a sudden temperature change in this area, determine that the location of the temperature change is the location of the anti-corona defect in the inner layer of the slot, repair this location, and repeat steps SA1, SA21, SA22, SB1, SB21 and SB22; if the temperature in this area does not increase significantly, determine that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the slot; the anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the slot is poor overlapping and hollowing in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the slot, and the hollowing includes hollowing between the inner layer low resistance anti-corona tape 91 and the main insulation of the wire rod, and hollowing between the inner layer low resistance anti-corona tape 91 and the first inner layer high resistance anti-corona tape 92.

[0038] Please see Figure 3 , the stator bar end anti-corona defect detection method comprises the following steps:

[0039] SB1. Apply high-frequency pulse test power to the stator bar 9;

[0040] SB21. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner high-resistance anti-corona belt of the first end. If a sudden temperature change occurs in this area, determine that the location of the sudden temperature change is the location of the inner anti-corona defect of the first end, repair this location, and repeat steps SA1, SA21, SA22, SB1, SB21 and SB22; if the temperature of this area does not increase significantly, determine that there is no anti-corona defect in the overlapping area of ​​the inner high-resistance anti-corona belt of the first end; the inner anti-corona defect of the first end is poor overlapping and hollowing in the overlapping area of ​​the inner high-resistance anti-corona belt of the first end, and the hollowing includes hollowing between the first inner high-resistance anti-corona belt 92 or the second inner high-resistance anti-corona belt 93 and the main insulation of the wire rod, hollowing between the first inner high-resistance anti-corona belt 92 and the second inner high-resistance anti-corona belt 93, and hollowing between the first inner high-resistance anti-corona belt 92 or the second inner high-resistance anti-corona belt 93 and the anti-corona protective layer 95 at the end of the wire rod.

[0041] SB22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner high-resistance anti-corona belt of the second end. If a sudden temperature change occurs in this area, determine that the location of the sudden temperature change is the location of the inner anti-corona defect of the second end, repair this location, and repeat steps SA1, SA21, SA22, SB1, SB21 and SB22; if the temperature of this area remains unchanged, determine that there is no anti-corona defect in the overlapping area of ​​the inner high-resistance anti-corona belt of the second end; the inner anti-corona defect of the second end is poor overlapping and hollowing in the overlapping area of ​​the inner high-resistance anti-corona belt of the second end, and the hollowing includes hollowing between the third inner high-resistance anti-corona belt 94 and the main insulation of the wire rod, hollowing between the second inner high-resistance anti-corona belt 93 and the third inner high-resistance anti-corona belt 94, and hollowing between the third inner high-resistance anti-corona belt 94 and the anti-corona protective layer 95 at the end of the wire rod.

[0042] The detection method provided by the present invention uses a high-frequency pulse test power supply, and its frequency conversion parameters: impulse rise time, sudden change voltage and impulse voltage repetition rate, so that the insulation capacitive reactance of the stator wire bar 9 is rapidly reduced, and the rapidly increased capacitive current causes the electrothermal characteristics of the anti-corona layer in the slot area and the end of the stator wire bar 9 to change significantly, and can quickly detect the anti-corona defects in the slot area and the end of the stator wire bar 9, and effectively verify the rationality and reliability of the anti-corona structure design and process treatment of the stator wire bar 9 of the high-voltage motor.

[0043] The principles and implementation methods of the present invention are described in this article using specific embodiments. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for detecting anti-corona defects of stator bars of high-voltage motors, It is characterized in that It includes a stator wire rod slot anti-corona defect detection method, which is used to detect whether there is an anti-corona defect at the slot of the stator wire rod anti-corona layer, and the stator wire rod anti-corona layer slot includes the overlapping area of ​​the high- and low-resistance anti-corona belts in the inner layer of the slot and the overlapping area of ​​the high- and low-resistance anti-corona paints in the outer layer of the slot; The stator bar slot anti-corona defect detection method comprises the following steps: SA1. Apply high-frequency pulse test power to the stator bars; SA21. Use visual or infrared thermal imaging to observe the temperature and discharge of the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch. If there is a sudden temperature change or discharge in this area, the location of the sudden temperature change is determined to be the location of the anti-corona defect of the outer layer of the notch. If there is no obvious increase in temperature or discharge in this area, it is determined that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch. The anti-corona defects in the overlapping area of ​​the high and low resistance anti-corona paint on the outer layer of the notch are poor overlap, missing points and uneven painting. SA22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch. If there is a sudden temperature change in this area, the position of the sudden temperature change is determined to be the position of the anti-corona defect in the inner layer of the notch; if the temperature in this area does not increase significantly, it is determined that there is no anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch; the anti-corona defect in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch is poor overlapping and hollowing in the overlapping area of ​​the high and low resistance anti-corona tapes in the inner layer of the notch, which includes hollowing between the inner layer low resistance anti-corona tape and the main insulation of the wire rod, and hollowing between the inner layer low resistance anti-corona tape and the first inner layer high resistance anti-corona tape; It also includes a stator wire rod end anti-corona defect detection method for detecting whether there is an anti-corona defect in the stator wire rod end anti-corona layer, the stator wire rod end anti-corona layer comprising a first end inner layer high-resistance anti-corona belt overlap region and a second end inner layer high-resistance anti-corona belt overlap region; The stator bar end anti-corona defect detection method comprises the following steps: SB1. Apply high-frequency pulse test power to the stator bars; SB21. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner layer high resistance anti-corona belt at the first end. If there is a sudden temperature change in this area, the position of the sudden temperature change is determined to be the position of the inner layer anti-corona defect at the first end; if the temperature in this area does not increase significantly, it is determined that there is no anti-corona defect in the overlapping area of ​​the inner layer high resistance anti-corona belt at the first end; the inner layer anti-corona defect at the first end is poor overlapping and voids in the overlapping area of ​​the inner layer high resistance anti-corona belt at the first end, and the voids include voids between the first inner layer high resistance anti-corona belt or the second inner layer high resistance anti-corona belt and the main insulation of the wire rod, voids between the first inner layer high resistance anti-corona belt and the second inner layer high resistance anti-corona belt, and voids between the first inner layer high resistance anti-corona belt or the second inner layer high resistance anti-corona belt and the anti-corona protective layer at the end of the wire rod; SB22. Use an infrared thermal imager to observe the temperature of the overlapping area of ​​the inner high-resistance anti-corona tape at the second end. If there is a sudden temperature change in this area, the location of the sudden temperature change is determined to be the location of the inner anti-corona defect at the second end; if the temperature in this area does not increase significantly, it is determined that there is no anti-corona defect in the overlapping area of ​​the inner high-resistance anti-corona tape at the second end; the inner anti-corona defect at the second end is poor overlapping and hollowing in the overlapping area of ​​the inner high-resistance anti-corona tape at the second end, and the hollowing includes hollowing between the third inner high-resistance anti-corona tape and the main insulation of the wire rod, and hollowing between the second inner high-resistance anti-corona tape and the third inner high-resistance There are gaps between the anti-corona belts, and there are gaps between the third inner high-resistance anti-corona belt and the anti-corona protection layer at the end of the wire rod; the peak-to-peak voltage of the high-frequency pulse test power supply in step SA1 and / or step SB1 is 1.0~1.1 times the rated voltage value of the motor corresponding to the stator wire rod, and the voltage is maintained for 2~3 minutes; the output waveform of the high-frequency pulse test power supply in step SA1 and / or step SB1 is a square wave, and the impulse rise time is less than 2μs; the impulse voltage repetition rate of the high-frequency pulse test power supply in step SA1 and / or step SB1 is 8~20kHz.

2. The method for detecting anti-corona defects of a high-voltage motor stator bar according to claim 1, It is characterized in that The step SA1 and / or step SB1 is performed at room temperature after the stator bar anti-corona layer is cured.

3. The method for detecting anti-corona defects of a high-voltage motor stator bar according to claim 1, It is characterized in that In the step SA21, after the position of the anti-corona defect in the outer layer of the notch is determined, the position is repaired and steps SA1 and SA21 are repeated.

4. The method for detecting anti-corona defects of a high-voltage motor stator bar according to claim 1, It is characterized in that In the step SA22, after the position of the anti-corona defect in the inner layer of the notch is determined, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

5. The method for detecting anti-corona defects of a high-voltage motor stator bar according to claim 1, It is characterized in that In the step SB21, after the position of the anti-corona defect in the inner layer of the first end is determined, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

6. The method for detecting anti-corona defects of a high-voltage motor stator bar according to claim 1, It is characterized in that In the step SB22, after the position of the anti-corona defect in the inner layer of the second end is determined, the position is repaired, and steps SA1, SA21, SA22, SB1, SB21 and SB22 are repeated.

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