Method and system for positioning insulation fault of stator winding of large and medium-sized motor

Abstract

The invention relates to the technical field of motor engineering, in particular to a large and medium-sized motor stator winding insulation fault positioning method and system.The method comprises the steps that after a motor stator breaks down, the phase of the fault is determined firstly, insulation resistance testing is conducted on a three-phase stator winding, the phase of the fault is judged, and preparation is made for fault positioning; searching a fault point by using a high-voltage pulse discharge method, observing the position of an electric spark through high-voltage pulse discharge to find the position of a fault bar, and marking the bar slot number of a fault phase winding; the method is wide in application scene, suitable for positioning various stator winding insulation breakdown faults, clear and definite in phenomenon, convenient to observe and confirm, capable of accurately positioning the fault bar, simple in step, short in test time, high in accuracy and efficiency, capable of effectively shortening the processing time and high in practicability. And power failure loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motor engineering, and in particular to a method and system for locating insulation faults of stator windings of large and medium-sized motors. Background Art

[0002] The stator is the basic component of the motor (including generators and motors), usually composed of a stator frame, an iron core, windings, etc. The stator winding of the motor generally uses a bar coil or a ring coil. Most large and medium-sized motors use a double-layer wave winding of a bar coil (also known as a wire bar), which is layered and embedded in the slots of the stator core. There are many stator windings in large and medium-sized motors, and the insulation quality of the stator winding is crucial to the safe operation of the generator. It is a common fault that some wire bars of the stator winding cause the main insulation to break down to the ground or short circuit between phases due to poor design and manufacturing process, installation defects, poor operation and maintenance, aging of insulation materials, etc. If the motor has a stator winding insulation fault, the running motor may cause the motor protection to stop due to the breakdown of the stator wire bar insulation. The motor under maintenance may have the stator wire bar insulation breakdown during the DC withstand voltage and leakage current test or AC withstand voltage test. The stator insulation fault has a large impact range and a long processing time. Quickly and accurately finding the insulation fault point can quickly and effectively isolate the fault and shorten the time to replace the faulty wire bar.

[0003] Since the stator bars are sealed in the slots, the actual troubleshooting is very complicated and the fault location is difficult. At present, the engineering practice methods for finding and locating stator winding insulation faults mainly include capacitor discharge method, AC burning method, segmented search method, ground voltage method, infrared or ultraviolet imaging detection, etc. The capacitor discharge method usually uses an insulation megohmmeter to charge a large-capacity capacitor, and then uses the charged capacitor to discharge the stator winding to find the fault point. This method charges slowly and has a small range of discharge voltage options. It is not suitable for finding faulty stator windings with large grounding transition resistance. When using the AC burning method to test faulty stator windings with large grounding resistance, it is difficult to determine the specific location through smoke, light, etc. due to the small current on the high-voltage side. At the same time, the AC burning method may also seriously burn the stator core. The segmented search method requires more separation and removal of the stator winding, which is labor-intensive and may also create new quality risks. The ground voltage method has accurate test results when the stator winding is metallically grounded, but the test error is large when the grounding transition resistance is large, and this method usually needs to be used in combination with the segmented search method, which has a limited scope of application. Infrared or ultraviolet imaging cannot be detected during shutdown, and cannot be accurately located after a stator insulation fault. These methods have the disadvantages of a single application scenario and inaccurate positioning of the faulty wire rod. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the technical problem to be solved by the present invention is: when an insulation breakdown fault occurs in the stator winding, whether in operation or maintenance, the insulation fault point can be accurately and quickly found, and the faulty wire rod can be accurately located, so that the fault can be quickly and effectively isolated, the time for handling the faulty wire rod can be shortened, and the power outage loss can be reduced. This patent is based on the capacitor discharge method and the segmented search method, optimizes the test method, improves the test tool, and selects pulse discharge voltages of different voltage levels for discharge according to the grounding resistance of the faulty stator winding. Continuous multiple discharges are conducive to observing and confirming the insulation breakdown point of the stator winding. Combined with the stator installation drawings and materials, the number and position of the slots of the stator winding insulation breakdown wire rod can be accurately located.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for locating insulation faults in stator windings of large and medium-sized motors, comprising: after a fault occurs, determining the fault phase of the motor stator; after confirming the fault phase of the motor stator, preparing for fault locating; using high-voltage pulses to find the fault point; and based on observation, confirming and replacing the position of the faulty wire rod.

[0007] As a preferred solution of the method for locating insulation faults of stator windings of large and medium-sized motors described in the present invention, the determination of the faulty phases of the motor stator includes removing the soft connections of the stator output lines and the neutral point end of the faulty motor, and performing insulation resistance and absorption ratio tests on the three-phase stator windings with an insulation megger, and short-circuiting the two non-tested phases to ground when testing one phase.

[0008] As a preferred solution of a method for locating insulation faults in stator windings of large and medium-sized motors described in the present invention, the fault locating preparation includes removing the upper and lower windshields of the motor stator after confirming the faulty phase of the motor stator, and using the stator expansion diagram to mark the slot number of the wire rod of the faulty phase in the stator core.

[0009] As a preferred solution of a method for locating insulation faults in stator windings of large and medium-sized motors described in the present invention, the fault finding includes searching based on high-voltage pulses at the fault point, grounding the non-fault phase, charging the high-voltage pulse generator, and finding the fault point by adjusting the high-voltage pulse voltage.

[0010] As a preferred solution of a method for locating insulation faults in stator windings of large and medium-sized motors described in the present invention, the confirmation and replacement of the position of the faulty wire rod includes observing the discharge position in the fixed slot wedge, determining the faulty wire rod according to the discharge position, and replacing the faulty wire rod after all the faulty wire rods are found.

[0011] As a preferred solution of the method for locating insulation faults of stator windings of large and medium-sized motors described in the present invention, the high-voltage pulse includes adjusting the adjustable discharge gap to select a suitable high-voltage pulse voltage to perform continuous pulse discharge on the faulty winding, and the discharge position can be determined by observing the position of the discharge spark; after the discharge is completed, the test switch is disconnected, the discharge switch is closed, the instrument is discharged, and the position of the faulty wire rod slot is diagnosed.

[0012] As a preferred solution of a method for locating insulation faults of stator windings of large and medium-sized motors described in the present invention, wherein: the discharge position includes, if the discharge position is obvious and the discharge breakdown position is clearly the end of the upper wire bar and the insulating pad strip below the slot wedge, the upper wire bar in the slot is confirmed to be a faulty wire bar; if the discharge trace cannot be clearly caused by the breakdown of the upper or lower wire bar, the stator wire bar insulation box is removed, the header block between the upper and lower wire bars is opened, the upper wire bar is isolated with an insulating partition, and the insulation resistance is tested in sections. If the insulation resistance of the two sections of the stator winding meets the specification requirements, the upper wire bar is confirmed to be a faulty wire bar.

[0013] Another object of the present invention is to provide a positioning system for insulation faults in stator windings of large and medium-sized motors. The system can accurately locate the faulty wire rods of the stator windings, accurately identify the specific slots where the insulation of the stator windings is broken down through an improved pulse discharge method combined with the stator installation drawings, effectively shorten the troubleshooting time, and reduce the losses caused by downtime due to faults.

[0014] In order to solve the above technical problems, the present invention provides the following technical solutions: a positioning system for insulation faults of stator windings of large and medium-sized motors, comprising: a fault phase identification module, a positioning preparation module, a fault search module and a wire rod replacement module;

[0015] The fault phase identification module determines the fault phase of the motor stator after the fault occurs;

[0016] The positioning preparation module performs fault positioning preparation after confirming the fault phase of the motor stator;

[0017] The fault finding module uses high voltage pulses to find the fault point;

[0018] The wire rod replacement module confirms and replaces the position of the faulty wire rod based on observation.

[0019] A computer device includes a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of the method for locating insulation faults of stator windings of large and medium-sized motors as described above are implemented.

[0020] A computer-readable storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the steps of the method for locating insulation faults of stator windings of large and medium-sized motors as described above are implemented.

[0021] The beneficial effects of the present invention are as follows: it has a wide range of application scenarios and is applicable to the location of stator winding insulation breakdown faults in all scenarios; when locating the generator stator winding insulation fault, the phenomenon is clear and definite, which is convenient for observation and confirmation; the faulty stator wire rod is accurately located, the steps are simple, and the test takes less time, and it has the advantages of being simple, practical, accurate and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0023] Figure 1 A flow chart of a method for locating insulation faults in stator windings of large and medium-sized motors provided by an embodiment of the present invention.

[0024] Figure 2 A method for locating insulation faults in stator windings of large and medium-sized motors provided by an embodiment of the present invention is a flow chart of motor stator winding fault locating taking a B-phase fault as an example.

[0025] Figure 3 A schematic diagram of a V-phase stator winding test wiring diagram of a method for locating insulation faults in stator windings of large and medium-sized motors provided by an embodiment of the present invention.

[0026] Figure 4 An example diagram of a C-phase stator expansion of a method for locating insulation faults in stator windings of large and medium-sized motors provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0028] Example 1, reference Figure 1-Figure 4 , is an embodiment of the present invention, which provides a method for locating insulation faults of stator windings of large and medium-sized motors, comprising:

[0029] After a fault occurs, determine the fault phase of the motor stator;

[0030] After confirming the fault phase of the motor stator, prepare for fault location;

[0031] Use high voltage pulses to locate fault points;

[0032] Based on observation, confirm and replace the location of the faulty wire rod.

[0033] It should be noted that if Figure 2 As shown, when the motor has a stator winding insulation breakdown failure, the running motor protection will trip and should be inspected after the motor is shut down and safety isolation measures are implemented; when inspecting the motor, the preventive test process and test parameters should be checked to confirm that they meet the requirements of the regulations and specifications, and the test interference factors should be eliminated and the safety measures should be reconfirmed before fault finding and locating.

[0034] Further, to determine the faulty phase of the motor stator, after the motor stator winding insulation fault occurs, it is first necessary to determine which phase (phase A, phase B or phase C) has the fault, and to determine it through insulation resistance testing. When the insulation resistance test is performed on the three-phase stator windings respectively, the insulation resistance of the faulty phase is significantly lower than the normal value, and the insulation resistance may be close to zero;

[0035] Then, prepare for fault location. First, confirm the stator winding phase where the fault occurs, and then perform more accurate fault location. According to the manufacturer's generator stator expansion diagram, that is, Figure 4 , mark the specific slot number and wire bar position of the phase winding in the stator core, and prepare for the subsequent high-voltage pulse discharge test to ensure that the discharge phenomenon can be correctly observed and the fault point can be determined during the test.

[0036] Furthermore, according to Figure 3 The use of high-voltage pulses to locate fault points mainly uses high-voltage pulse discharge testing. The lead-out end of the faulty phase winding is connected to the high-voltage pulse generator. After the equipment is powered on, pulse discharge is performed on the faulty phase according to the set voltage level. The location of the faulty wire rod is determined by observing the electric spark at the discharge point. According to the different insulation resistances, an appropriate high-voltage discharge voltage is selected to ensure that the discharge phenomenon is obvious.

[0037] Secondly, confirm and replace the faulty wire rod position. After completing the high-voltage pulse discharge test, observe the discharge position and combine it with the manufacturer's generator stator expansion diagram. Figure 4 , the stator core slot number where the faulty wire bar is located can be accurately determined. If the discharge phenomenon is obvious and the discharge traces are concentrated on the upper or lower wire bar in a certain slot, it can be confirmed that the wire bar is a faulty wire bar. The faulty wire bar needs to be removed and replaced to ensure that the insulation state of the motor stator winding is restored to normal levels.

[0038] Example 2, reference Figure 3-Figure 4 , is an embodiment of the present invention, which provides a method for locating insulation faults of stator windings of large and medium-sized motors, comprising:

[0039] S1: After a fault occurs, determine the fault phase of the motor stator.

[0040] It should be noted that determining the faulty phase of the motor stator includes removing the stator output line and neutral point soft connection of the faulty motor, and using an insulation megger to perform insulation resistance and absorption ratio tests on the three-phase stator windings. When testing one phase, the two phases not being tested are short-circuited to ground.

[0041] Furthermore, when the difference between each phase or each branch is greater than 100% of the minimum value, or the epoxy powder mica insulation absorption ratio is less than 1.6, or the manufacturer's technical document requirements are not met, the insulation resistance is unqualified; the insulation resistance of the phase with obvious insulation defects in the stator winding is low, and in severe cases, the insulation resistance to ground is zero when tested with a 2500V megger, and the insulation resistance to ground is several hundred kilo-ohms when tested with a 500V megger, which can confirm the insulation fault of the stator winding phase;

[0042] Furthermore, if the insulation of the stator winding of the faulty phase recovers and the difference in the insulation resistance of the three phases is small, the absorption ratio or polarization index of each phase can be further compared, and then further confirmed through a DC withstand voltage test. If the withstand voltage test of the non-faulty phase passes, the stator winding will break down again during the withstand voltage test of the faulty phase, thereby determining the faulty phase of the stator winding.

[0043] S2: After confirming the fault phase of the motor stator, prepare for fault location.

[0044] It should be noted that the fault location preparation includes removing the upper and lower (front and rear) windshields of the motor stator after confirming the fault phase of the motor stator, and using the manufacturer's stator expansion diagram, that is, Figure 4 , mark the slot number of the faulty phase bar in the stator core.

[0045] Furthermore, personnel were sent to observe the discharge position around the stator (front and back) during the test, and the non-fault phase was grounded and the fault phase was connected to the attached Figure 3 Connect the fault phase V1 to the high-voltage output terminal of the high-voltage pulse generator, and connect the grounding point of the generator stator base to the grounding terminal of the high-voltage pulse generator.

[0046] Figure 3The dotted line in the middle is the internal schematic diagram of the high-voltage pulse tester. One end of the instrument is connected to the V1 end of the motor stator winding (the V-phase output terminal), and the other end (usually the ground terminal by default) is connected to the motor stator core base. During the test, close the test switch, check that the discharge switch is disconnected, and when adjusting the adjustable discharge gap, select a suitable voltage for high-voltage pulse discharge; after the discharge is completed, disconnect the test switch, close the discharge switch to discharge the instrument and the circuit, and after the discharge, test the test product and then remove the test wiring.

[0047] S3: Use high voltage pulses at the fault point to find the fault.

[0048] It should be noted that fault finding includes searching based on the high-voltage pulse of the fault point, grounding the non-fault phase, charging the high-voltage pulse generator, and finding the fault point by adjusting the high-voltage pulse voltage; the high-voltage pulse includes selecting a suitable high-voltage pulse voltage by adjusting the adjustable discharge gap to perform continuous pulse discharge on the faulty winding, and the discharge position can be determined by observing the position of the discharge spark; after the discharge is completed, the test switch is disconnected, the discharge switch is closed, the instrument is discharged, and the position of the faulty wire rod in the slot is diagnosed; the discharge position includes, if the discharge position is obvious and the discharge breakdown position is clearly the end of the upper wire rod and the insulating pad under the slot wedge, it is confirmed that the upper wire rod of the slot is the faulty wire rod; if the discharge mark cannot be clearly caused by the breakdown of the upper or lower wire rod, the stator wire rod insulation box is removed, the header block between the upper and lower wire rods is opened, and the upper wire rod is isolated with an insulating partition, and the insulation resistance is tested in sections. If the insulation resistance of the two sections of the stator winding meets the requirements of the specification, the upper wire rod is confirmed to be the faulty wire rod.

[0049] Furthermore, the high-voltage pulse generator is charged, and the voltage is selected according to the stator-to-ground insulation resistance of the faulty phase according to the recommended value in Table 1 (assuming that the faulty phase is phase B). The adjustable discharge gap is adjusted to select a suitable high-voltage pulse voltage to perform continuous pulse discharge on the faulty winding. The stator core slot number M of the discharge point can be determined by observing the position of the discharge spark.

[0050] As shown in Table 1 below, R is the insulation resistance measured in the stator winding (unit: MΩ), UN is the rated line voltage of the generator (unit: kV), and UN+1 represents the minimum requirement for the insulation resistance of the rotating electrical machine. After the main insulation of the generator stator winding is completely broken down, the insulation resistance tested by a 2500V insulation megohmmeter is 0, but affected by other covering materials such as slot linings and gaskets, a lower insulation resistance may be measured at a lower voltage using an electronic megohmmeter; after the main insulation of the stator winding is partially broken down, there may be recovery, and the insulation resistance value can be measured using a 2500V insulation megohmmeter; in order to reduce the damage to the generator core during discharge, the initial test voltage should be as small as possible. If the discharge phenomenon is not obvious, the discharge voltage can be gradually increased.

[0051] Table 1 Correspondence between stator winding fault phase insulation resistance and high voltage pulse discharge test voltage

[0052]

[0053] Furthermore, after the discharge is completed, the test switch is disconnected, and the discharge switch is closed to discharge the instrument; the position of the faulty wire rod in the slot is diagnosed by comparing the stator expansion diagram of the manufacturer's technical drawing: when the upper and lower layer wire rods of the M slot are in different phases, the B-phase branch in the upper and lower layer wire rods can be determined as the faulty stator wire rod;

[0054] When the upper and lower wire bars of the M slot are both phase B, the stator M slot wedge can be opened for observation if necessary. If the discharge position is obvious and the discharge breakdown position is clearly the end of the upper wire bar and the insulating pad under the slot wedge, it can be directly confirmed that the upper wire bar of the slot is the faulty wire bar.

[0055] S4: Based on observation, confirm and replace the location of the faulty wire rod.

[0056] It should be noted that confirming and replacing the position of the faulty wire rod includes observing the discharge position in the wedge, determining the faulty wire rod according to the discharge position, and replacing the faulty wire rod after all the faulty wire rods are found.

[0057] Furthermore, when the discharge marks cannot be clearly caused by the breakdown of the upper or lower wire rods, the insulation box of the M-slot stator wire rod is removed, the header block between the upper and lower wire rods is opened, and the upper wire rod is isolated with an insulating partition. The insulation resistance of the B-phase stator winding is tested in sections. If the insulation resistance of the two sections of the stator winding meets the requirements of the specification, it can be confirmed that the upper wire rod is a faulty wire rod; conversely, after isolating the upper wire rod of the M-slot, at least one section of the B-phase winding does not meet the requirements of the specification, it can be confirmed that the lower wire rod of the M-slot is a faulty wire rod.

[0058] Furthermore, after confirming the position of the faulty wire rod in the M slot, open the wire rod header block, isolate the upper and lower wire rods, and perform insulation resistance tests on the remaining winding segments of phase B. If the insulation resistance of the segments is qualified, it is confirmed that there is only one faulty wire rod; if the insulation resistance of at least one segment of the segmented winding is unqualified, repeatedly perform high-voltage pulse discharge on the unqualified insulation resistance part to find and confirm the remaining faulty wire rods; after finding all the faulty wire rods, the stator winding can be preventively tested again after replacing the faulty wire rods, and it can be put into operation normally after passing the test.

[0059] The above is a schematic scheme of a method for locating insulation faults of stator windings of large and medium-sized motors in this embodiment. It should be noted that the technical scheme of the system for locating insulation faults of stator windings of large and medium-sized motors and the technical scheme of the method for locating insulation faults of stator windings of large and medium-sized motors described above belong to the same concept. The details of the technical scheme of the system for locating insulation faults of stator windings of large and medium-sized motors in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the method for locating insulation faults of stator windings of large and medium-sized motors described above.

[0060] Example 3, reference Figure 4 An embodiment of the present invention provides a method for locating insulation faults in stator windings of large and medium-sized motors. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0061] The rated power of a hydropower plant generator is 35MW, and the rated voltage is 10.5kV. The stator core is made of high-magnetic permeability, low-loss, and non-aging high-quality silicon steel sheets, and the whole circle is composed of 16 sheets. The number of slots in the generator stator core is Z = 144, the number of slots per pole per phase is q = 4, and the pitch is 1-11-25. The stator winding is a strip wave winding, which is a single wire rod connected in a Y-shaped branch and woven from glass sintered wire. When the No. 3 generator was overhauled, the generator was subjected to a thermal engine test according to the specifications. The insulation resistance and absorption ratio of the No. 3 unit before DC withstand voltage were qualified, and the DC resistance was qualified. According to the preventive test requirements, the stator winding of the No. 3 unit was subjected to leakage current and DC withstand voltage tests. The test voltage was 2.0UN, and it was increased in stages by 0.5UN per level, and each stage stayed for 1 minute. When the test voltage of the stator C phase winding was increased to 16.9kV (1.6UN), the leakage current of the C phase winding was about 35μA, and the DC high-voltage tester suddenly tripped. After stopping the test, the test instrument and related wiring conditions were checked to be normal. After discharging the C phase winding of the stator of unit 3, the insulation resistance was retested. After inspection, the insulation resistance of unit 3 was qualified. The C phase stator winding was tested again. When the voltage was increased to 7.1kV, the leakage current was about 65μA, and the voltage was unstable. After stopping the test, the insulation resistance of the C phase winding was checked and cleaned after the C phase lead wire and neutral point were qualified. When the voltage was increased to 6.5kV during the test again, the leakage current suddenly jumped from about 15μA to 400μA, and there was a discharge sound in the stator winding, and the DC high-voltage instrument tripped. When testing the insulation resistance, the test voltage stayed at about 170V and could not rise. The insulation resistance was 0.05MΩ, and it was judged that the insulation of the C phase winding was broken down.

[0062] The upper frame of Unit 3 was dismantled, and the generator rotor was hoisted out and a platform was set up. The stator slot numbers were marked according to the manufacturer's stator installation technical drawings, and then the C-phase stator winding was discharged with an adjustable pulse high-voltage generator. The discharge voltage was adjusted to 2.5kV, and continuous pulse discharge was observed at the 32 slot position of the stator winding with obvious electric sparks. After the stator discharge was completed, the instrument was discharged, and after opening the slot wedge of slot 32, it was checked that there was an obvious breakdown point in the main insulation below the straight part of the upper wire rod of slot 32. Through the manufacturer's technical drawing stator expansion diagram, it was confirmed that the upper wire rod of slot 32 was phase B, and the faulty wire rod was the upper wire rod of slot 32.

[0063] like Figure 4 As shown in the figure, it is an example of the stator expansion diagram of the manufacturer's technical drawing. W1 represents the stator winding at the phase C end, and W2 represents the stator winding at the neutral point of phase C. After determining the slot number of the faulty wire rod, it can be determined whether the wire rod is in the upper layer or the lower layer according to the stator expansion diagram. For example, in the example, the faulty phase of phase C is determined, and slot 32 is the slot number of the faulty wire rod. According to the stator expansion diagram, the upper wire rods of slots 29-32 are all C-phase wire rods, so it can be confirmed that the faulty wire rod in slot 32 is the upper wire rod.

[0064] Embodiment 4 is an embodiment of the present invention, which provides a positioning system for insulation faults of stator windings of large and medium-sized motors, including: a fault phase identification module, a positioning preparation module, a fault search module and a wire rod replacement module;

[0065] The fault phase identification module determines the fault phase of the motor stator after the fault occurs;

[0066] The positioning preparation module performs fault positioning preparation after confirming the fault phase of the motor stator;

[0067] The fault finding module uses high voltage pulses to find the fault point;

[0068] The wire rod replacement module confirms and replaces the position of the faulty wire rod based on observation.

[0069] This embodiment further provides a computing device, which is applicable to a method for locating insulation faults of stator windings of large and medium-sized motors, and includes:

[0070] A memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement a method for locating insulation faults of stator windings of large and medium-sized motors as proposed in the above embodiment.

[0071] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, a method for locating insulation faults of stator windings of large and medium-sized motors as proposed in the above embodiment is implemented.

[0072] The storage medium proposed in this embodiment and the method for locating insulation faults of stator windings of large and medium-sized motors proposed in the above embodiment belong to the same inventive concept. The technical details not described in detail in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0073] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0074] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0075] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0076] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for locating insulation faults of stator windings of large and medium-sized motors, characterized in that: include: After a fault occurs, determine the fault phase of the motor stator; After confirming the fault phase of the motor stator, prepare for fault location; Use high voltage pulses to locate fault points; Based on observation, confirm and replace the location of the faulty wire rod.

2. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 1, characterized in that: The method of determining the faulty phase of the motor stator includes removing the stator output line and the neutral point soft connection of the faulty motor, performing insulation resistance and absorption ratio tests on the three-phase stator windings respectively with an insulation megger, and short-circuiting the two non-tested phases to ground when testing one phase.

3. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 2, characterized in that: The fault location preparation includes, after confirming the fault phase of the motor stator, removing the upper and lower windshield plates of the motor stator, and marking the slot number of the wire rod of the fault phase in the stator core using the stator expansion diagram.

4. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 3, characterized in that: The fault finding includes finding the fault point according to the high-voltage pulse, grounding the non-fault phase, charging the high-voltage pulse generator, and finding the fault point by adjusting the high-voltage pulse voltage.

5. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 4, characterized in that: The confirming and replacing the position of the faulty wire rod comprises observing the discharge position in the wedge, determining the faulty wire rod according to the discharge position, and replacing the faulty wire rod after all the faulty wire rods are found.

6. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 5, characterized in that: The high-voltage pulse includes adjusting the adjustable discharge gap to select a suitable high-voltage pulse voltage to perform continuous pulse discharge on the faulty winding, and the discharge position can be determined by observing the position of the discharge spark; after the discharge is completed, the test switch is disconnected, the discharge switch is closed, the instrument is discharged, and the position diagnosis in the fault line rod slot is performed.

7. A method for locating insulation faults of stator windings of large and medium-sized motors as claimed in claim 6, characterized in that: The discharge position includes: if the discharge position is obvious and the discharge breakdown position is clearly the end of the upper wire bar and the insulating pad under the slot wedge, the upper wire bar in the slot is confirmed to be a faulty wire bar; if the discharge trace cannot be clearly caused by the breakdown of the upper or lower wire bar, the stator wire bar insulation box is removed, the header block between the upper and lower wire bars is opened, the upper wire bar is isolated with an insulating partition, and the insulation resistance is tested in sections. If the insulation resistance of the two sections of the stator winding meets the specification requirements, the upper wire bar is confirmed to be a faulty wire bar.

8. A system for locating insulation faults of stator windings of large and medium-sized motors based on any one of claims 1 to 7, characterized in that: include: Fault phase identification module, positioning preparation module, fault finding module and wire rod replacement module; The fault phase identification module determines the fault phase of the motor stator after the fault occurs; The positioning preparation module performs fault positioning preparation after confirming the fault phase of the motor stator; The fault finding module uses high voltage pulses to find the fault point; The wire rod replacement module confirms and replaces the position of the faulty wire rod based on observation.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the processor implements the steps of a method for locating insulation faults of stator windings of large and medium-sized motors as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for locating insulation faults of stator windings of large and medium-sized motors according to any one of claims 1 to 7 are implemented.

Images