EFPI optical fiber sensor for motor corona monitoring

Abstract

The utility model discloses an EFPI optical fiber sensor for motor corona monitoring, which relates to the field of generator stator winding insulation on-line monitoring, and comprises a signal collection shell, a main body shell, a diaphragm, a connecting block and an optical fiber, the signal collection shell is fixedly connected with a sensor main body, is trumpet-shaped and is connected with the main body shell, one end of the main body shell is provided with a groove, and the other end of the main body shell is provided with the diaphragm. A through hole penetrating through the main body shell is formed, and the diaphragm is positioned in the groove and is in contact with the signal collecting shell; a through hole is formed in the contact position of the signal collecting shell and the diaphragm, one end of the connecting block is connected with the diaphragm, and the other end is connected with the groove; the optical fiber part is sleeved with an optical fiber sleeve, and the part extending out of the sensor is provided with an optical fiber sheath; a buckle structure is fixed on the sensor shell, and a coating is further arranged in the signal collecting shell. According to the utility model, the on-line monitoring of the corona at the end part of the stator winding can be realized, oil stains, dust and the like attached to the surface of the vibrating diaphragm in a unit are reduced, and the signal receiving sensitivity of the sensor and the portability of installation and maintenance are improved.

Description

Technical Field

[0001] The utility model relates to the field of online monitoring of generator stator winding insulation, in particular to an EFPI optical fiber sensor for motor corona monitoring. Background Art

[0002] Corona at the ends of large motor stator windings is one of the main factors leading to insulation degradation. Currently, corona at the ends of stator windings is detected through visual inspection and corona testing during downtime, lacking reliable and effective online monitoring methods. Corona is a type of partial discharge in the air. During the corona process, it is accompanied by many characteristics such as sound, light, electromagnetic waves, and ozone. These are also the main monitoring basis for corona / arc discharge in current power systems. EFPI fiber optic ultrasonic sensors have the advantages of small size, strong resistance to electromagnetic interference, high sensitivity, and excellent insulation properties. They are currently widely used in partial discharge monitoring of power equipment such as transformers, GIS, and air switches. Due to the complex rotating mechanical structure of generators, strong electromagnetic and mechanical noise occurs during operation, making conventional ultrasonic sensors unable to be directly applied.

[0003] Chinese patent publication number CN205373872U, published on July 6, 2016, discloses a fiber-optic EFPI ultrasonic sensor. The sensor head unit comprises a sensor head unit and a sensor body unit. The sensor body unit includes a sensor sheath. The sensor head unit is disposed within the sensor sheath. The sensor head unit includes a capillary tube, a portion of an optical fiber disposed within the capillary tube, and a ferrule holder for securing the optical fiber. A diaphragm for sensing ultrasonic vibrations is disposed at one end of the capillary tube. The inner surface of the diaphragm, the front end face of the optical fiber, and the inner surface of the capillary tube collectively define a Fabry-Perot cavity. The front end face of the optical fiber constitutes the first reflection surface of the Fabry-Perot cavity, and the inner surface of the diaphragm constitutes the second reflection surface of the Fabry-Perot cavity. This fiber-optic EFPI ultrasonic sensor can efficiently respond to and acquire ultrasonic signals, exhibiting high sensitivity and measurement accuracy.

[0004] However, the technical solution with the publication number CN205373872U is, on the one hand, inconvenient to install and maintain the sensor, and difficult to fix on the end of the stator winding or other parts; on the other hand, the diaphragm of the above technical solution is directly set at the bottom, and oil, dust, etc. in the unit are easily attached to the diaphragm; and the signal receiving range of this technical solution is not easy to determine, which increases the difficulty in designing the sensor network layout plan. Utility Model Content

[0005] To solve the above technical problems, the utility model proposes an EFPI optical fiber sensor for motor corona monitoring, which can realize online monitoring of corona at the end of the stator winding, reduce the adhesion of oil, dust, etc. on the diaphragm surface in the unit, and improve the sensitivity of the sensor.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] An EFPI optical fiber sensor for motor corona monitoring comprises a signal collecting shell and a sensor body, wherein the signal collecting shell is fixedly connected to the sensor body, and the sensor body comprises a main body shell, a diaphragm, a connecting block and an optical fiber, the signal collecting shell is trumpet-shaped, and is connected to the main body shell, a groove is provided at one end of the main body shell close to the signal collecting shell, and a through hole penetrating the main body shell is provided at the groove, the diaphragm is provided in the groove and contacts the signal collecting shell; a through hole is provided at the portion where the signal collecting shell contacts the diaphragm, one end of the connecting block is connected to the diaphragm, and the other end is connected to the end face of the groove; one end of the optical fiber extends into the main body shell and is flush with the plane of the connecting block, and the other end extends out of the sensor shell; the part of the optical fiber arranged in the main body shell is provided with an optical fiber sleeve, and the part extending out of the sensor is provided with an optical fiber sheath; a snap-fit ​​structure is fixed to the sensor shell by bolts, and a coating is also provided in the signal collecting shell, and the coating comprises a hydrophobic coating, an oleophobic coating or a self-cleaning coating.

[0008] The contact angle of the hydrophobic coating, oleophobic coating or self-cleaning coating is greater than 90°.

[0009] The cross section of the signal collecting shell is rectangular.

[0010] The buckle structure includes an arc-shaped metal sheet, and a plurality of bolt holes are provided at both ends of the arc-shaped metal sheet.

[0011] The snap-fit ​​structure is used to fix the sensor on an annular structure arranged according to the structural space of the stator coil end.

[0012] The length of the optical fiber sheath is 10-15 mm.

[0013] The thickness of the membrane is 20-30 μm and the diameter is 2-3 mm.

[0014] The signal collecting shell is made of a material with a temperature resistance exceeding 60°C.

[0015] The thickness of the membrane is 25 μm and the diameter is 2 mm.

[0016] The main body shell is formed into one body with the diaphragm, the connecting block and the optical fiber by potting or bonding with F-class epoxy resin.

[0017] Compared with the prior art, the advantages of this utility model are:

[0018] 1. The signal collection shell of this utility model adopts a trumpet-shaped design, which collects ultrasonic signals within a certain range and improves the sensitivity of the sensor receiving signal. A single sensor has a clear signal collection range, which reduces the difficulty of designing a large-scale and large-quantity sensor network layout scheme; and a snap-fit ​​mechanism is provided on the sensor housing for easy installation and maintenance.

[0019] 2. In the present invention, a hydrophobic coating, an oleophobic coating or a self-cleaning coating is provided on the surface of the signal collecting shell, which can prevent the oil inside the machine from adhering to the surface of the diaphragm and affecting its sensitivity.

[0020] 3. In the present utility model, a plurality of bolt holes are provided at both ends of the arc-shaped metal sheet of the snap-fit ​​structure, so that the bolt fixing position can be adjusted according to the specific actual situation during installation, reducing the vibration caused by size mismatch and improving the accuracy of the sensor. In addition, the fixing method is simple to operate and has strong applicability, and does not affect the original structure of the motor, thereby reducing the operation risk.

[0021] 4. The utility model can be used at a high temperature for a long time, thereby improving the stability of motor corona monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0023] Figure 1 It is a structural diagram of the present utility model.

[0024] Markings in the figure:

[0025] 1. Signal collecting shell, 2. Diaphragm, 3. Connecting block, 4. Main body shell, 5. Optical fiber sheath, 6. Optical fiber sleeve, 7. Optical fiber, 8. Snap-fit ​​structure, 9. Coating. DETAILED DESCRIPTION

[0026] Example 1

[0027] As the most basic embodiment of the present invention, an EFPI optical fiber 7 sensor for motor corona monitoring includes a signal collecting shell 1 and a sensor body. The signal collecting shell 1 is fixedly connected to the sensor body. The sensor body includes a main body shell 4, a diaphragm 2, a connecting block 3 and an optical fiber 7. The signal collecting shell 1 is trumpet-shaped and is connected to the main body shell 4. The main body shell 4 is provided with a groove at one end close to the signal collecting shell 1, and a through hole penetrating the main body shell 4 is provided at the groove. The diaphragm 2 is provided in the groove and contacts the signal collecting shell 1. ; A through hole is provided at the portion where the signal collecting shell 1 contacts the diaphragm 2, one end of the connecting block 3 is connected to the diaphragm 2, and the other end is connected to the end face of the groove; one end of the optical fiber 7 extends into the main shell 4 and is flush with the plane of the connecting block 3, and the other end extends out of the sensor shell; the part of the optical fiber 7 arranged in the main shell 4 is sleeved with an optical fiber sleeve 6, and a optical fiber sheath 5 is provided on the part extending out of the sensor; a snap-fit ​​structure 8 is fixed on the sensor shell by bolts, and a coating 9 is also provided in the signal collecting shell 1, and the coating 9 includes a hydrophobic coating 9, an oleophobic coating 9 or a self-cleaning coating 9.

[0028] In this embodiment, the signal collecting shell 1 adopts a trumpet-shaped design, which collects ultrasonic signals within a certain range and improves the sensitivity of the sensor receiving signal. A single sensor has a clear signal collection range, which reduces the difficulty of designing a large-scale and large-quantity sensor networking layout scheme; and a snap-fit ​​mechanism is provided on the sensor housing for easy installation and maintenance; and a hydrophobic coating, an oleophobic coating or a self-cleaning coating is also provided in the signal collecting shell, which can prevent oil stains in the machine from adhering to the surface of the diaphragm and affecting its sensitivity.

[0029] Example 2

[0030] As a preferred embodiment of the present invention, an EFPI optical fiber 7 sensor for motor corona monitoring includes a signal collection shell 1 and a sensor body. The signal collection shell 1 is fixedly connected to the sensor body. The sensor body includes a main body shell 4, a diaphragm 2, a connecting block 3 and an optical fiber 7. The signal collection shell 1 is trumpet-shaped. The signal collection shell 1 is connected to the main body shell 4. The main body shell 4 is close to the signal collection shell 1. A groove is provided at one end, and a through hole is provided at the groove that penetrates the main body shell 4. The diaphragm 2 is provided in the groove and contacts the signal collection shell 1. ; A through hole is provided at the portion where the signal collecting shell 1 contacts the diaphragm 2, one end of the connecting block 3 is connected to the diaphragm 2, and the other end is connected to the end face of the groove; one end of the optical fiber 7 extends into the main shell 4 and is flush with the plane of the connecting block 3, and the other end extends out of the sensor shell; the part of the optical fiber 7 arranged in the main shell 4 is sleeved with an optical fiber sleeve 6, and a optical fiber sheath 5 is provided on the part extending out of the sensor; a snap-fit ​​structure 8 is fixed on the sensor shell by bolts, and a coating 9 is also provided in the signal collecting shell 1, and the coating 9 includes a hydrophobic coating 9, an oleophobic coating 9 or a self-cleaning coating 9.

[0031] The signal collecting shell 1 is provided with a hydrophobic, oleophobic, self-cleaning material coating 9, the contact angle of which is greater than 90°, which can prevent the oil inside the machine from adhering to the surface of the diaphragm and affecting its sensitivity.

[0032] The cross section of the signal collecting housing 1 is rectangular.

[0033] The snap-fit ​​structure 8 comprises a curved metal sheet with several bolt holes at each end. It is bolted to the sensor housing, allowing for adjustment of the bolt fixing position during installation based on actual conditions, reducing vibration caused by size mismatches and improving sensor accuracy. The snap-fit ​​structure 8 secures the sensor to an annular structure aligned with the stator coil end structure. This simple, adaptable, and non-destructive fixing method reduces operational risks by not affecting the original motor structure.

[0034] Example 3

[0035] As the best embodiment of the present utility model, an EFPI optical fiber 7 sensor for motor corona monitoring includes a signal collection shell 1 and a sensor body. The signal collection shell 1 is fixedly connected to the sensor body. The sensor body includes a main body shell 4, a diaphragm 2, a connecting block 3 and an optical fiber 7. The signal collection shell 1 is trumpet-shaped. The signal collection shell 1 is connected to the main body shell 4. The main body shell 4 is close to the signal collection shell 1. A groove is provided at one end, and a through hole is provided at the groove that penetrates the main body shell 4. The diaphragm 2 is provided in the groove and contacts the signal collection shell 1. ; A through hole is provided at the portion where the signal collecting shell 1 contacts the diaphragm 2, one end of the connecting block 3 is connected to the diaphragm 2, and the other end is connected to the end face of the groove; one end of the optical fiber 7 extends into the main shell 4 and is flush with the plane of the connecting block 3, and the other end extends out of the sensor shell; the part of the optical fiber 7 arranged in the main shell 4 is sleeved with an optical fiber sleeve 6, and a optical fiber sheath 5 is provided on the part extending out of the sensor; a snap-fit ​​structure 8 is fixed on the sensor shell by bolts, and a coating 9 is also provided in the signal collecting shell 1, and the coating 9 includes a hydrophobic coating 9, an oleophobic coating 9 or a self-cleaning coating 9.

[0036] The signal collecting shell 1 is provided with a hydrophobic, oleophobic, self-cleaning material coating 9, the contact angle of which is greater than 90°, which can prevent the oil inside the machine from adhering to the surface of the diaphragm and affecting its sensitivity.

[0037] The cross section of the signal collecting housing 1 is rectangular.

[0038] The snap-fit ​​structure 8 comprises a curved metal sheet with several bolt holes at each end. It is bolted to the sensor housing, allowing for adjustment of the bolt fixing position during installation based on actual conditions, reducing vibration caused by size mismatches and improving sensor accuracy. The snap-fit ​​structure 8 secures the sensor to an annular structure aligned with the stator coil end structure. This simple, adaptable, and non-destructive fixing method reduces operational risks by not affecting the original motor structure.

[0039] The length of the optical fiber sheath 5 is 10-15 mm.

[0040] The thickness of the membrane 2 is 20-30 μm and the diameter is 2-3 mm.

[0041] The signal collecting housing 1 is made of a material with a temperature resistance exceeding 60°C.

[0042] The thickness of the membrane 2 is 25 μm and the diameter is 2 mm.

[0043] The main housing 4 is formed into one piece with the diaphragm 2, the connecting block 3 and the optical fiber 7 by potting or bonding with F-class epoxy resin.

[0044] This embodiment proposes an EFPI optical fiber 7 sensor for motor corona monitoring, which can realize online monitoring of corona at the end of the stator winding. The signal reception is stable, and it can reduce the adhesion of oil, dust, etc. on the diaphragm surface in the unit, improve the sensitivity of the sensor, and can operate at higher temperatures for a long time.

Claims

1. An EFPI optical fiber sensor for motor corona monitoring, characterized by: The invention comprises a signal collecting shell (1) and a sensor body, wherein the signal collecting shell (1) is fixedly connected to the sensor body, and the sensor body comprises a main body shell (4), a diaphragm (2), a connecting block (3) and an optical fiber (7), wherein the signal collecting shell (1) is horn-shaped, and the signal collecting shell (1) is connected to the main body shell (4), and a groove is provided at one end of the main body shell (4) close to the signal collecting shell (1), and a through hole penetrating the main body shell (4) is provided at the groove, and the diaphragm (2) is provided in the groove and contacts the signal collecting shell (1); the signal collecting shell (1) and the diaphragm (2) are connected to each other. ) is provided with a through hole at the contact position, one end of the connecting block (3) is connected to the diaphragm (2), and the other end is connected to the end face of the groove; one end of the optical fiber (7) extends into the main housing (4) and is flush with the plane of the connecting block (3), and the other end extends out of the sensor housing; the part of the optical fiber (7) arranged in the main housing (4) is provided with an optical fiber sleeve (6), and the part extending out of the sensor is provided with an optical fiber sheath (5); a snap-fit ​​structure (8) is fixed on the sensor housing by bolts, and a coating (9) is also provided in the signal collecting housing (1), and the coating includes a hydrophobic coating, an oleophobic coating or a self-cleaning coating.

2. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The contact angle of the hydrophobic coating, oleophobic coating or self-cleaning coating is greater than 90°.

3. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The cross section of the signal collecting shell (1) is rectangular.

4. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The buckle structure (8) comprises an arc-shaped metal sheet, and a plurality of bolt holes are provided at both ends of the arc-shaped metal sheet.

5. The EFPI optical fiber sensor for motor corona monitoring according to claim 4, characterized in that: The snap-on structure (8) is used to fix the sensor on an annular structure arranged according to the structural space of the stator coil end.

6. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The length of the optical fiber sheath (5) is 10-15 mm.

7. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The signal collecting shell (1) is made of a material with a temperature resistance exceeding 60°C.

8. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The thickness of the membrane (2) is 20-30 μm and the diameter is 2-3 mm.

9. The EFPI optical fiber sensor for motor corona monitoring according to claim 8, characterized in that: The thickness of the diaphragm (2) is 25 μm and the diameter is 2 mm.

10. The EFPI optical fiber sensor for motor corona monitoring according to claim 1, characterized in that: The main body shell (4) is integrally formed with the diaphragm (2), the connecting block (3) and the optical fiber (7) by potting or bonding with F-class epoxy resin.

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