A method for overhauling a gas engine stator and a detection and repair system

Abstract

The present application relates to the technical field of motor maintenance, and discloses a kind of based on the maintenance method and detection repair system of gas generator stator, the based on the maintenance method of gas generator stator, comprising: S100: to stator winding is disassembled, and record its structure parameter;S200: to stator winding end is dynamic characteristic test, detects modal frequency and vibration mode;S300: to stator winding is vacuum pressure impregnation treatment, including pre-baking, vacuum dehumidification, stage pressurization curing including.The present application is by optimizing vacuum pressure impregnation process and mica tape composite insulation structure, effectively eliminates the bubble residual of insulating layer, improves anti-corona and ageing resistance;Introduce winding end modal frequency quantitative detection means, accurately identify electromagnetic vibration risk, avoid structural resonance damage;Adopt Leeb hardness gauge quantitative evaluation slot wedge tightness, combined with epoxy resin curing process enhances mechanical stability, solves the problem of insufficient precision of traditional manual detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor maintenance methods, more specifically, it relates to a maintenance method based on a stator of a gas generator and a detection and repair system. BACKGROUND

[0002] As the core equipment of the power system, the stator of the gas generator is long-term operated under the complex working conditions of high temperature, dust pollution and electromagnetic vibration, which easily leads to insulation material aging, slot wedge loosening and other faults. The existing maintenance technology is mostly focused on the replacement of the rotor, bearing maintenance and other conventional projects, and lacks targeted strategies for systematic maintenance of the stator. Especially for the unitized and centralized gas generator set, due to the low heat dissipation efficiency and the operating environment temperature far exceeding the design value (up to the rated temperature + 40℃ in summer), the insulation deterioration process of the stator winding is accelerated. In the long-term operation, dust accumulation, overvoltage impact and periodic thermal stress further aggravate the problems of wire bar insulation layer cracking and slot wedge displacement, causing multiple stator ground faults and seriously threatening the safety of the 10kV power grid.

[0003] At present, the traditional maintenance method of the stator of the gas generator mainly adopts the fault maintenance mode, which makes it difficult to prevent the systematic risk caused by the degradation of insulation performance. The technical defects are as follows: in the aspect of insulation repair technology, the conventional impregnation process has the problem of residual bubbles in the winding, which causes the long-term existence of partial discharge hazards; the lack of quantitative detection means for the vibration mode of the winding end in the dynamic characteristic evaluation link cannot effectively predict the structural damage risk caused by electromagnetic force resonance; the control of slot wedge tightness still relies on the experience judgment mode such as manual knocking, which has the problems of low detection precision and unquantifiable data; the real-time state monitoring system does not construct a distributed temperature sensor network, which is difficult to capture abnormal working conditions such as wire bar overheating in time. The above shortcomings in the aspects of insulation treatment process, dynamic characteristic detection and state monitoring to some extent restrict the active operation and maintenance ability of the health status of the stator of the gas generator, therefore, a maintenance method and detection and repair system suitable for the operation characteristics of the gas generator are urgently needed. SUMMARY

[0004] The purpose of the present application is to provide a maintenance method and detection and repair system based on the stator of a gas generator to solve the above technical problems.

[0005] The present application solves the above existing technical problems through the following technical solutions:

[0006] The present application provides a maintenance method based on the stator of a gas generator, comprising:

[0007] S100: disassembling the stator winding and recording its structure parameters;

[0008] S200: Dynamic characteristic test is performed on the end of the stator winding to detect modal frequency and mode shape;

[0009] S300: Vacuum pressure impregnation treatment is performed on the stator winding, including pre-baking, vacuum dehumidification, and staged pressure curing;

[0010] S400: Slot wedge is installed and tightness is detected;

[0011] S500: Temperature sensor is arranged between the stator bars and connected to the monitoring terminal;

[0012] S600: Insulation performance and withstand voltage test is performed on the repaired stator.

[0013] Preferably, in step S300, the specific process parameters of the vacuum pressure impregnation treatment are as follows:

[0014] Vacuum dehumidification pressure is less than or equal to 26.6 Pa, and is maintained for 3-4 hours;

[0015] Pressure is increased in stages to 0.6-0.7 MPa, and is maintained for 5-9 hours;

[0016] Curing temperature is 155-165℃, and curing time is 16-17 hours.

[0017] Preferably, in step S400, 1-2 adjusting pad strips are installed at the bottom of the slot wedge, and are fixed by epoxy resin paint, and tightness is detected by using a Leeb hardness tester.

[0018] Preferably, in step S500, the temperature sensor is symmetrically arranged between the upper and lower bars at 2 per phase.

[0019] A detection and repair system for implementing the maintenance method of the gas generator stator, comprising:

[0020] A vacuum pressure impregnation module for performing vacuum dehumidification and impregnation curing of the stator winding;

[0021] A dynamic characteristic test module for detecting the vibration characteristics of the end of the stator winding;

[0022] A slot wedge tightness detection module for measuring the mechanical parameters of the installed slot wedge;

[0023] A distributed temperature monitoring module for real-time acquisition and transmission of stator bar temperature data;

[0024] An insulation performance test module for power frequency withstand voltage and insulation resistance detection.

[0025] Preferably, the vacuum pressure impregnation module comprises an impregnation tank, a vacuum extraction assembly, a partition assembly, a paint conveying pipeline and a suspension rack, the partition assembly is arranged in the impregnation tank and is used for dividing the impregnation tank into an inner layer impregnation area and an outer layer impregnation area, the paint conveying pipeline is in communication with the bottom of the inner layer impregnation area and the outer layer impregnation area respectively, and the suspension rack is used for placing the stator.

[0026] Preferably, the partition assembly comprises an isolation cylinder body which is fixed vertically to the inner bottom wall of the impregnation tank, a plurality of through holes are uniformly arranged on the side of the isolation cylinder body, and a blocking rotating piece for blocking the through holes is arranged on the inner side of the isolation cylinder body.

[0027] Preferably, the impregnation tank is provided with an opening at the top, and the top of the suspension rack is clamped on the opening when the suspension rack is suspended in the inner layer impregnation area.

[0028] Preferably, the dynamic characteristic test module comprises a force hammer sensor and a frequency response analysis unit, and can collect winding end vibration signals and calculate modal parameters.

[0029] Preferably, the slot wedge tightness detection module integrates a Leeb hardness tester and a frequency response analysis unit, and can synchronously output hardness values and resonance frequency data.

[0030] The beneficial effects of the present application are that:

[0031] The present application optimizes the vacuum pressure impregnation process and the mica tape composite insulation structure, effectively eliminates the residual bubbles in the insulation layer, improves the anti-corona and aging resistance, introduces the winding end modal frequency quantitative detection means, accurately identifies the electromagnetic vibration risk, avoids the structural resonance damage, uses the Leeb hardness tester to quantitatively evaluate the slot wedge tightness, enhances the mechanical stability in combination with the epoxy resin curing process, solves the problem of insufficient precision of traditional manual detection, simultaneously constructs a distributed temperature monitoring network, captures the overheating abnormality of the wire rod in real time, and greatly shortens the fault response time. The whole method combines the preventive test standard and the digital detection data, forms a closed-loop management system from insulation repair, dynamic characteristic regulation to temperature monitoring, realizes the transformation of the stator maintenance of the gas generator from passive repair to predictive maintenance, comprehensively deals with the insulation deterioration, slot wedge loosening and overheating hidden danger under the complex working conditions such as high temperature, dust and electromagnetic vibration, prolongs the service life of the equipment and guarantees the safe operation of the power grid. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a flow chart of a maintenance method based on a stator of a gas generator provided by the present application;

[0033] Figure 2 is a structural schematic view of a vacuum impregnation module in a stator detection and repair system based on a gas generator provided by the present application;

[0034] Figure 3It is a kind of vacuum paint immersion module internal structure schematic diagram provided in the stator detection and repair system of the gas generator of the present application.

[0035] Figure 4 It is a cutaway view of the paint immersion tank provided in the present application.

[0036] Figure 5 It is a structure schematic diagram between the interlayer assembly and the suspension frame body provided in the present application.

[0037] In the figure: 1, paint immersion tank; 11, opening; 2, vacuum extraction assembly; 3, interlayer assembly; 31, isolation cylinder; 32, plugging rotating part; 33, inner layer paint immersion area; 34, outer layer paint immersion area; 4, paint conveying pipeline; 5, suspension frame body. DETAILED DESCRIPTION

[0038] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the present description. Various examples can omit, substitute, or add various procedures or components as appropriate. Also, features described with respect to some examples can be combined in other examples. Example One

[0039] Please refer to Figure 1 A kind of based on the stator repair method of gas generator, comprising:

[0040] S100: disassembling the stator winding, and recording its structure parameters

[0041] Before disassembling the stator winding, the wire diameter, length and winding mode of each winding wire rod are measured, to ensure that the parameters of the repaired stator winding are consistent with the original data.

[0042] Material selection: materials should have a qualified certificate, and the repair method should meet the requirements of GB / T4074.1-2008 "Winding wire test method Part 1: General provisions" and GB / T4074.2-2008 "Winding wire test method Part 2: Dimension measurement".

[0043] S200: dynamic characteristic test is carried out on the end of the stator winding, and modal frequency and vibration mode are detected

[0044] During the dynamic characteristic test, the dynamic characteristic test of the end of the stator winding should meet the current national standard GB / T20140-2006 "Turbo type generator stator winding end dynamic characteristic and vibration test method and evaluation".

[0045] S300: Vacuum pressure impregnation treatment of stator winding, including pre-baking, vacuum dehumidification, staged pressure curing

[0046] During vacuum pressure impregnation, the stator is pre-baked for 3-6 hours, then vacuum dehumidification is started, the pressure in the tank is less than 26.6 Pa, the vacuum time is maintained for 3-4 hours, then the stator is cooled to 40-55℃ and impregnated under vacuum, then the vacuum is gradually released in stages and the pressure is gradually increased, and the pressure in the final stage is 0.6-0.7 MPa, 5-9 hours; circulating in hot air at 155±5℃-165±5℃, curing for 16-17 hours.

[0047] For the selection of insulating materials, the ground insulation of the stator bar is wrapped with mica tape, and in order to avoid the formation of corona or electric spark, the inner part of the bar slot is covered with conductive paint, and the end winding is covered with resistive paint.

[0048] S400: Install slot wedge and detect its tightness

[0049] Slot wedge installation: When installing the slot wedge, 1-2 spacer bars are installed at the bottom according to the tightness, and after installation, it should be checked that there is no looseness or cracking, then coated with epoxy resin paint to ensure that the bar can withstand strong electromagnetic force without vibration or loosening.

[0050] Slot wedge inspection: The slot wedge should not protrude from the inner surface of the core, and the tightness of the slot wedge should be checked with a Leeb hardness tester, the data should be intuitive and accurate, and the measured data should be recorded and saved.

[0051] S500: Temperature sensors are arranged between the stator bars and connected to the monitoring terminal

[0052] The generator stator lead wire should use AWG-15kV-95 square high-temperature resistant cable and press European DT wire nose;

[0053] The generator stator coil is installed with 6 temperature sensors, which are installed and buried between the upper and lower bars, 2 for each phase, the sensor wiring is led through the wire pipe to the upper part of the terminal block in the secondary terminal box, which is used to monitor the real-time temperature of the A, B and C three-phase stator of the generator stator.

[0054] In addition, after the completion of the entire A-level maintenance step, the test needs to be carried out to ensure that the test parameters of the stator meet the relevant requirements in DL / T596-2021 "Preventive Test Regulations for Electrical Equipment". Example two

[0055] In addition, the application further provides a detection and repair system for implementing the above-mentioned overhauling method, comprising a vacuum pressure impregnation module, a dynamic characteristic test module and a slot wedge tightness detection module; wherein the vacuum pressure impregnation module is used for performing vacuum dehumidification and impregnation curing of the stator winding; the dynamic characteristic test module is used for detecting the vibration characteristics of the end of the stator winding; the dynamic characteristic test module comprises a force hammer sensor and a frequency response analysis unit, and can collect the winding end vibration signal and calculate the modal parameters; the slot wedge tightness detection module is used for measuring the mechanical parameters after the installation of the slot wedge; the slot wedge tightness detection module integrates a Leeb hardness tester and a frequency response analysis unit, and can synchronously output the hardness value and the resonance frequency data. A distributed temperature monitoring module is used for collecting and transmitting the stator bar temperature data in real time; and an insulation performance test module is used for power frequency voltage resistance and insulation resistance detection.

[0056] Specifically, please refer to Figures 2 to 5 The vacuum pressure impregnation module comprises an impregnation tank 1, a vacuum extraction assembly 2, a partition assembly 3, a paint conveying pipeline 4 and a suspension frame body 5, the partition assembly 3 is arranged in the impregnation tank 1 and is used for dividing the impregnation tank 1 into an inner layer impregnation area 33 and an outer layer impregnation area 34; the paint conveying pipeline 4 is in communication with the bottom of the inner layer impregnation area 33 and the outer layer impregnation area 34 respectively, and the suspension frame body 5 is used for placing the stator, and the size of the suspension frame body 5 can simultaneously adapt to the inner layer impregnation area 33 and the outer layer impregnation area 34. The partition assembly 3 comprises an isolation cylinder 31 which is vertically fixed to the inner bottom wall of the impregnation tank 1, a plurality of through holes are uniformly arranged on the circumferential side of the isolation cylinder 31, and a blocking rotating piece 32 for blocking the through holes is rotatably arranged on the inner side of the isolation cylinder 31; the top of the impregnation tank 1 is provided with an opening 11, and a sealing cover plate is arranged at the position of the opening 11, and the top of the suspension frame body 5 is clamped on the opening 11 when the suspension frame body 5 is suspended in the inner layer impregnation area 33; a suspension interface for connecting the suspension frame body 5 is arranged in the outer layer impregnation area 34; the vacuum extraction assembly 2 comprises a vacuum pump and a vacuum pipe, the vacuum pump is fixed to the outer side of the isolation cylinder 31, and the input end of the vacuum pump is in communication with the upper end of the impregnation tank 1 through the vacuum pipe; the two ends of the paint conveying pipeline 4 in communication with the inner layer impregnation area 33 and the outer layer impregnation area 34 are both provided with electromagnetic valves, and the end away from the impregnation tank 1 is in communication with an external paint conveying tank.

[0057] In use, the vacuum pressure paint dipping module needs to select the corresponding use mode according to the current paint dipping demand. When only a small amount of stators (for example, 2-3) need to be dipped, the inner layer paint dipping area 33 can be selected for dipping operation. The stators are placed on the hanging rack body 5, then the sealing cover plate is opened, the hanging rack body 5 is put in from the opening 11, the hanging rack body 5 gradually sinks into the isolation cylinder 31, until the top of the hanging rack body 5 is clamped with the opening 11, so that the hanging rack body 5 is in the inner layer paint dipping area 33 in the isolation cylinder 31, then the sealing cover plate is closed, the pressure in the paint dipping tank 1 is adjusted to a preset value by the vacuum pumping assembly 2, then the electromagnetic valve connected with the inner layer paint dipping area is opened, so that the paint liquid enters the inner layer paint dipping area 33 alone, until the paint liquid submerges the stators on the hanging rack body 5, waits for the dipping time to be completed, then the paint liquid is discharged through the paint conveying pipeline 4. If a large amount of stators need to be dipped, the outer layer paint dipping area 34 can be used alone for dipping. At this time, the top cover at the top of the paint dipping tank 1 is opened, then the hanging rack body 5 containing stators is evenly installed in the outer layer paint dipping area 34, then the electromagnetic valve connected with the outer layer paint dipping area 34 is opened, so that the paint liquid enters the outer layer paint dipping area 34 for dipping treatment. If the amount of stator dipping needs to be further increased, a hanging rack body 5 containing stators can be hung in the inner layer paint dipping area 33, the blocking rotating piece 32 can also be rotated to separate from the through hole, and the electromagnetic valve connected with the inner layer paint dipping area 33 is opened, so that the paint liquid enters the inner layer paint dipping area 33 and the outer layer paint dipping area 34 respectively. In this way, the vacuum pressure paint dipping module provided by the application has multiple dipping modes compared with the traditional paint dipping equipment, which can select the appropriate dipping area according to different dipping needs in actual use, so that the paint liquid can quickly submerge the stators in a short time, avoid the delay of paint liquid flow caused by excessive space, and achieve the purpose of improving the dipping efficiency.

[0058] The embodiments of the application are described above, but the application is not limited to the specific embodiments described above, which are only illustrative and not restrictive. Those skilled in the art can make many forms under the inspiration of the application, which all belong to the protection of the application.

Claims

1. A detection and repair system based on a gas generator stator, characterized in that: include: Vacuum pressure impregnation module, used to perform vacuum dehumidification and impregnation curing of stator windings; Dynamic characteristics test module, used to detect the vibration characteristics of the stator winding end; Slot wedge tightness detection module, used to measure the mechanical parameters of the slot wedge after installation; Distributed temperature monitoring module, used to collect and transmit stator bar temperature data in real time; Insulation performance test module, used for power frequency withstand voltage and insulation resistance testing; The vacuum pressure dipping module includes a dipping tank, a vacuum pumping assembly, a barrier assembly, a paint delivery pipe, and a hanging frame. The barrier assembly is arranged in the dipping tank and is used to divide the interior of the dipping tank into an inner dipping area and an outer dipping area. The paint delivery pipe is connected to the bottom of the inner dipping area and the bottom of the outer dipping area respectively. The hanging frame is used to place the stator. The barrier assembly includes an isolation cylinder vertically fixed to the bottom wall of the paint dipping tank, a plurality of through holes are evenly arranged on the circumference of the isolation cylinder, and a sealing rotating member is rotatably provided inside the isolation cylinder for sealing the through holes; The top of the paint dipping tank is provided with an opening, and when the hanging frame is hung in the inner paint dipping area, the top of the hanging frame is clamped on the opening.

2. A gas generator stator detection and repair system according to claim 1, characterized in that: The dynamic characteristics test module includes a hammer sensor and a frequency response analysis unit, which can collect the vibration signal of the winding end and calculate the modal parameters.

3. A gas generator stator detection and repair system according to claim 2, characterized in that: The slot wedge tightness detection module integrates a Leeb hardness tester and a frequency response analysis unit, and can synchronously output hardness values ​​and resonance frequency data.

4. A maintenance method, applicable to the detection and repair system based on the gas generator stator according to claim 1, characterized in that: include: S100: dismantling the stator winding and recording its structural parameters; S200: Perform dynamic characteristic test on the stator winding end to detect modal frequency and vibration shape; S300: Vacuum pressure impregnation treatment of stator windings, including pre-baking, vacuum dehumidification, and staged pressurized curing; S400: Install the slot wedge and check its tightness; S500: Temperature sensors are placed between stator bars and connected to monitoring terminals; S600: Conduct insulation performance and voltage withstand tests on the stator after maintenance.

5. A maintenance method according to claim 4, characterized in that: In step S300, the specific process parameters of the vacuum pressure immersion process are: Vacuum dehumidification pressure ≤ 26.6Pa, maintain for 3-4 hours; Increase the pressure to 0.6-0.7 MPa in stages and maintain for 5-9 hours; The curing temperature is 155-165°C and the curing time is 16-17 hours.

6. A maintenance method according to claim 4, characterized in that: In step S400, 1-2 adjusting pads are installed at the bottom of the slot wedge and fixed with epoxy resin paint, and the tightness is tested using a Leeb hardness tester.

7. A maintenance method according to claim 4, characterized in that: In step S500, the temperature sensors are symmetrically arranged between the upper and lower layers of wire rods, with two sensors per phase.

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