Fatigue test method and system for generator bar, medium and electronic equipment

Abstract

The invention relates to a fatigue test method and system for a generator bar, a medium and electronic equipment. The method comprises the following steps: applying a load to the generator bar through a load applying device to enable the bar to generate displacement; after the cycle number of the displacement of the bar reaches a preset number of times, determining a failure result of the bar through a withstand voltage test; and determining a fatigue test curve of the bar based on a failure result after the cycle times of the bar displacement reach different preset times, the fatigue test curve being an association relationship between the displacement amount of the bar and the failure times. According to the method, the fatigue performance of the winding bar is tested, the potential fatigue failure risk can be found in advance, the design and manufacturing process is optimized, and therefore the operation reliability of the variable-speed pumped storage generator set under frequent working condition conversion is improved.

Description

Technical Field

[0001] This application relates to the technical field of generators, and particularly to a fatigue test method, system, medium and electronic device for generator bars. Background Art

[0002] For a variable-speed pumped-storage generator, its rotor is a rotating component. During the operation of the online group, it not only has to bear the acting force caused by the electromagnetic force, but also has to bear the centrifugal force brought by high-speed rotation. When the variable-speed pumped-storage generator participates in grid peak shaving, frequency modulation and other operations, the working conditions change frequently, which will cause the load on the rotor bars to change frequently. Especially the end bars bear the largest alternating load, making the insulating medium of the end bars more likely to undergo fatigue failure under the long-term alternating load, thereby affecting the operation of the entire variable-speed pumped-storage generator. Summary of the Invention

[0003] Embodiments of this application provide a fatigue test method, system, medium and electronic device for generator bars to solve the above problems.

[0004] To achieve the above object, according to the first aspect of this application, a fatigue test method for generator bars is provided. The method includes:

[0005] Applying a load to the bars of the generator through a load applying device to cause displacement of the bars;

[0006] After the number of cycles of displacement of the bars reaches a preset number, determining the failure result of the bars through a withstand voltage test;

[0007] Based on the failure results after the number of cycles of displacement of the bars reaches different preset numbers, determining the fatigue test curve of the bars, where the fatigue test curve characterizes the correlation between the displacement amount and the number of cycles of the bars.

[0008] Optionally, the determining the failure result of the bars through a withstand voltage test includes:

[0009] Applying a voltage to the bars based on a preset starting voltage;

[0010] Increasing the voltage applied to the bars until the voltage applied to the bars reaches a preset full-value voltage;

[0011] After the time of applying the preset full-value voltage reaches a preset duration, reducing the voltage applied to the bars to determine the failure result of the bars according to whether there is a preset failure phenomenon in the bars.

[0012] Optionally, the determining the failure result of the bars according to whether there is a preset failure phenomenon in the bars includes:

[0013] When a breakdown phenomenon and / or a flashover phenomenon occurs in the coil bar, it is determined that the failure result of the coil bar is fatigue failure.

[0014] Optionally, the method further includes:

[0015] Determining test parameters of the withstand voltage test based on operating parameters of the coil bar, where the test parameters include at least one of a preset full value voltage, a preset starting voltage, a pressurization duration, and a voltage frequency.

[0016] Optionally, determining the fatigue test curve of the coil bar based on failure results after the number of cycles of displacement of the coil bar reaches different preset numbers includes:

[0017] For each preset load, based on the failure results after the number of cycles of displacement of the coil bar under the preset load reaches different preset numbers, taking the number of cycles when the failure result is fatigue failure as the failure number;

[0018] Determining the displacement amount of the coil bar corresponding to the failure number;

[0019] Based on the displacement amount corresponding to each failure number, determining the fatigue test curve of the coil bar; the fatigue test curve includes the correlation between the displacement amounts of multiple coil bars and the failure numbers.

[0020] Optionally, the displacement amount of the coil bar is related to the applied load of the load applying device;

[0021] Determining the fatigue test curve of the coil bar based on failure results after the number of cycles of displacement of the coil bar reaches different preset numbers includes:

[0022] Determining the load application range of the load applying device based on the preset fatigue limit number of the coil bar;

[0023] Based on the failure results after the number of cycles of displacement of the coil bar within the load application range reaches different preset numbers, determining the fatigue test curve of the coil bar within the load application range;

[0024] Optionally, during the process that the number of cycles of displacement of the coil bar reaches different preset numbers, the preset numbers are determined based on the preset fatigue limit number.

[0025] According to the third aspect of the present application, an embodiment of the present application further provides a fatigue test system for a generator coil bar, and the system includes:

[0026] A clamping device for fixing the coil bar;

[0027] A load applying device for applying a displacement load to the coil bar to cause the coil bar to displace;

[0028] A voltage withstand test device for applying voltage to the bar.

[0029] The control device is communicatively connected to the load applying device and the voltage withstand test device.

[0030] The control device is configured to:

[0031] Apply a load to the bar of the generator through the load applying device to cause displacement of the bar.

[0032] After the number of cycles of displacement of the bar reaches a preset number, determine the failure result of the bar through a voltage withstand test.

[0033] Based on the failure results after the number of cycles of displacement of the bar reaches different preset numbers, determine the fatigue test curve of the bar, where the fatigue test curve characterizes the correlation between the displacement amount and the number of cycles of the bar.

[0034] According to the third aspect of the present application, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements any one of the fatigue test methods for the generator bar provided by the embodiments of the present application.

[0035] According to the fourth aspect of the present application, an embodiment of the present application further provides an electronic device, including:

[0036] A memory on which a computer program is stored.

[0037] A processor for executing the computer program in the memory to implement any one of the fatigue test methods for the generator bar provided by the embodiments of the present application.

[0038] Some embodiments of this specification at least include the following beneficial effects: The end bars of the rotor of a variable-speed pumped-storage generator are prone to the action of alternating loads such as complex electromagnetic forces, centrifugal forces, and thermal stresses during operation, and their fatigue performance is related to the stability and reliability of the unit. Through the test of fatigue performance, potential fatigue failure risks can be discovered in advance, and the design and manufacturing processes can be optimized, thereby improving the operation reliability of the unit under frequent operating condition conversions.

[0039] Other features and advantages of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0041] To more fully understand the present application and its beneficial effects, the following will be described in conjunction with the accompanying drawings, where the same reference numerals in the following description represent the same parts.

[0042] Figure 1 is a schematic structural diagram of a fatigue test system for generator bars according to some embodiments of this specification;

[0043] Figure 2 is an exemplary flowchart of a fatigue test method for generator bars according to some embodiments of this specification;

[0044] Figure 3 is an exemplary flowchart of determining a fatigue test curve according to some embodiments of this specification;

[0045] Figure 4 is an exemplary schematic diagram of an end bar according to some embodiments of this specification;

[0046] Figure 5 is a schematic structural diagram of an electronic device according to some embodiments of this specification. Detailed implementation manners

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0048] To facilitate the understanding of the implementation solutions provided in the embodiments of the present application, the relevant application backgrounds of the fatigue test method for generator bars provided in the embodiments of the present application will be described first.

[0049] As the power system's requirements for stability continue to increase, variable-speed pumped-storage generators have gradually become a key development direction for the power system. Different from the pole structure used in the rotors of conventional pumped-storage generators, the rotors of variable-speed pumped-storage generators adopt a wound structure, similar to the stator winding, which is composed of multiple wire bars connected to each other at both ends of the rotor through a unique wiring method, forming end wire bars outside the iron core. This makes the rotor not only affected by electromagnetic forces during operation but also by centrifugal forces. When variable-speed pumped-storage generators participate in grid peak shaving, frequency modulation, and other regulation tasks, the operating conditions change frequently, resulting in frequent changes in the loads on the rotor wire bars. In particular, the alternating loads on the end wire bars are the largest. The end wire bars are composed of copper wires and insulating media, and among them, the insulating media are more likely to undergo fatigue failure under long-term alternating loads. Once the insulating media fail, it will lead to a decrease in the operating reliability of the entire variable-speed pumped-storage unit and may even cause significant economic losses.

[0050] In view of this, some embodiments of this specification provide a fatigue test method for generator wire bars. By performing fatigue tests on the end wire bars of the rotors of variable-speed pumped-storage generators, the fatigue life characteristics of different materials and structural forms can be clarified, thereby optimizing the insulation structure, fixing method, and material selection of the wire bars. Once the insulating media of the rotor end wire bars undergo fatigue failure, it may lead to the shutdown and maintenance of the entire unit, causing huge economic losses. Through fatigue performance testing, weak links can be identified and improved in advance, and a reasonable maintenance plan can be formulated. For example, by determining the inspection cycle and replacement standards for key components, the maintenance costs and losses in power generation revenue caused by fault shutdowns can be effectively reduced. This not only helps to extend the service life of the unit but also reduces the maintenance costs. By testing the fatigue performance of the rotor end wire bars, the regulation ability and operating efficiency of the unit can be further improved, better adapting to the dynamic demands of the power grid.

[0051] Figure 1 It is a schematic structural diagram of a fatigue test system for generator wire bars shown in some embodiments of this specification.

[0052] As Figure 1 shown, the fatigue test system 100 for generator wire bars may include a clamping device 110, a load application device 120, a withstand voltage test device 130, and a control device 140, where:

[0053] The clamping device is used to fix the wire bar;

[0054] The load application device is used to apply a displacement load to the wire bar to cause the wire bar to displace;

[0055] The withstand voltage test device is used to apply a voltage to the wire bar;

[0056] The control device is communicatively connected to the load application device and the withstand voltage test device,

[0057] The control device is configured to:

[0058] Apply a load to the bar of the generator through a load application device to cause displacement of the bar;

[0059] After the number of cycles of bar displacement reaches a preset number, determine the failure result of the bar through a withstand voltage test;

[0060] Based on the failure results after the number of cycles of bar displacement reaches different preset numbers, determine the fatigue test curve of the bar, and the fatigue test curve characterizes the correlation between the displacement amount and the number of cycles of the bar.

[0061] The clamping device 110 is used to clamp the bar. For example, the clamping device 110 may include a screw clamping fixture, a hydraulic / pneumatic fixture, a V-groove fixture, etc.

[0062] In some embodiments, the clamping device 110 may include a clamping portion, a driving portion, a base, an adjusting portion, a protection portion, etc.

[0063] In some embodiments, the driving portion (such as a screw, a hydraulic cylinder, a pneumatic cylinder, etc.) is connected to the clamping portion to realize clamping or releasing of the bar by transmitting force. For example, in a screw clamping fixture, the screw is threadedly connected to the clamping portion, and rotating the screw can push the clamping portion to move. Another example is that in a hydraulic / pneumatic fixture, the piston rod of the hydraulic cylinder or pneumatic cylinder is connected to the clamping portion by a pin shaft or a bolt, and the expansion and contraction of the piston rod drives the clamping portion to move. The driving portion is usually fixed on the base to ensure its stability during operation. For example, in a hydraulic fixture, the hydraulic cylinder is fixed on the base by bolts or flanges.

[0064] The clamping portion can be mounted on the base and move through a slide rail, a guide rod or other guiding structures to clamp the bar.

[0065] The adjusting portion (such as an adjusting nut, a pressure valve, etc.) is connected to the driving portion and is used to adjust the clamping force or adapt to bars of different sizes.

[0066] In some embodiments, the protection portion (such as a rubber pad, an anti-slip coating, etc.) is mounted on the contact surface of the clamping portion and fixed by bonding, buckling or embedding, etc. The protection portion can reduce the pressure concentration of the clamping portion on the surface of the bar and prevent damage to the surface of the bar.

[0067] In some embodiments, the control device 140 can be communicatively connected to the driving portion to send a first control parameter to the adjusting portion, and the adjusting portion can control the output parameters (such as clamping force or stroke) of the driving portion based on the first control parameter.

[0068] The load application device 120 is used to apply a load to a preset position of the wire bar. For example, the load application device 120 may include an electric servo actuator, a hydraulic actuator, etc. The load may be, for example, pressure, tension, radial force, displacement, etc.

[0069] In some embodiments, the load application device 120 may include a bracket, a guiding part, an actuating part, a control part, etc. Among them, the bracket can be fixed to the workbench by bolts, the guiding part (such as a guide rail) is fixed to the bracket by screws, the actuating part (such as an electric servo motor or a hydraulic cylinder) is fixed to the bracket by a flange or a bracket, and the actuating part is also connected to a fixture (such as a collet chuck, a V-groove fixture, etc.) by bolts or buckles. The control part is used to adjust the motion parameters (such as displacement, speed) of the actuating part.

[0070] In some embodiments, the control device 140 may be communicatively connected to the control part to send a second control parameter to the control part, and the control part may control the motion parameters (such as displacement, speed) of the actuating part based on the second control parameter.

[0071] The withstand voltage test device 130 is used to apply a voltage to a preset position of the wire bar. For example, the withstand voltage test device 130 may include a power frequency withstand voltage test device, a series resonance withstand voltage test device, an AC withstand voltage test device, etc.

[0072] Exemplarily, for the power frequency withstand voltage test device, the power frequency power supply is connected to the wire bar through the high-voltage output terminal of the test transformer, and the power frequency power supply drives the test transformer to boost the voltage and apply an AC voltage to the wire bar. Exemplarily, for the series resonance withstand voltage test device, the variable frequency power supply drives the resonance circuit (inductor and capacitor) to generate a high voltage, and the high-voltage output terminal is connected to the wire bar through a shielded cable to apply an AC voltage to the wire bar.

[0073] In some embodiments, the fatigue test system 100 for generator wire bars may further include a monitoring device (not shown in the figure), and the monitoring device refers to a device for monitoring the relevant states of the fatigue test system 100 for generator wire bars. In some embodiments, the monitoring device may include a voltmeter, an ammeter, a megohmmeter, an image acquisition device, etc. The image acquisition device may include a camera, an infrared sensor, etc.

[0074] In some embodiments, a voltmeter, a megohmmeter, etc. may be installed at both ends of the wire bar to measure the voltage, insulation resistance, etc. of the wire bar.

[0075] In some embodiments, the image acquisition device (such as a camera) is usually installed in front of or on the side of the wire bar to clearly record the appearance changes of the wire bar. In some embodiments, in order to comprehensively observe the cracks, deformations, ablation, etc. of the wire bar, multiple cameras may be installed to collect images from different angles.

[0076] The control device 140 can process data and / or information obtained from other devices or system components. The control device 140 can execute program instructions based on such data, information, and / or processing results to perform one or more functions described in the present application.

[0077] In some embodiments, the control device 140 can include one or more sub-processing devices (e.g., a single-core processing device or a multi-core and multi-chip processing device). By way of example only, a Central Processing Unit (CPU), an Application-Specific Integrated Circuit (ASIC), an Application-Specific Instruction-set Processor (ASIP), a Graphics Processing Unit (GPU), etc., or any combination thereof.

[0078] In some embodiments, the control device 140 can be communicatively connected to the clamping device 110, the load application device 120, the withstand voltage test device 130, and the monitoring device. In some embodiments, based on the data of the monitoring device, the control device 140 can, through control instructions, control the clamping device 110 to clamp the wire bar, control the load application device 120 to apply a displacement load to a preset position of the wire bar, and control the withstand voltage test device 130 to perform a withstand voltage test on the wire bar.

[0079] In some embodiments, the fatigue test system 100 for generator wire bars can further include a user terminal (not shown in the figure). The user terminal refers to one or more terminal devices or software used by a user. In some embodiments, one or more users can use the user terminal, which can include users directly using the fatigue test system for generator wire bars, as well as other relevant users. In some embodiments, the user terminal can be a mobile device, a tablet computer, a laptop computer, a desktop computer, or any other device with input and / or output functions, or any combination thereof.

[0080] In some embodiments, the fatigue test system 100 for generator wire bars can further include, for example, a network, a storage device, etc. The network can include any suitable wired or wireless network that can facilitate the exchange of information and / or data. The storage device is used to store data, instructions, and / or any other information.

[0081] It should be noted that the above description of the fatigue test system for generator bars and its components is only for convenience of description and does not limit this specification to the scope of the examples given. It can be understood that for those skilled in the art, after understanding the principle of the system, various parts may be arbitrarily combined, or a subsystem may be formed and connected to other modules without departing from this principle. In some embodiments, Figure 1 the clamping device 110, the load application device 120, and the withstand voltage test device 130 disclosed in

[0082] Figure 2 can be different modules in a system, or a single module can implement the functions of two or more of the above modules. Such deformations are all within the protection scope of this specification. Figure 2 is an exemplary flowchart of a fatigue test method for generator bars according to some embodiments of this specification. In some embodiments, process 200 can be executed based on a control device. As

[0083] shown, process 200 includes the following steps.

[0084] The bar can be a stator bar, a rotor bar, or a certain component of the bar, such as an end bar.

[0085] The load refers to the work done on the bar by the load application device. For example, through a load application device (such as a hydraulic servo system, an electric actuator, etc.), an external force or displacement load is applied to a preset position of the bar to push the bar to generate displacement.

[0086] The displacement load refers to applying a preset displacement amount to the bar through the load application device during the fatigue test.

[0087] The displacement refers to the change amount of the bar moving from the initial position to the final position. For example, during the fatigue test, the load device can apply a load to a preset position of the bar, and the preset position can be determined based on experiments or experience.

[0088] The displacement can include the shape change amount or position change amount of the preset position of the bar under the action of an external force.

[0089] In some embodiments, the control device can be communicatively connected to the load application device and control the load application device to apply a displacement load to the bar based on set parameters.

[0090] The set parameters can include, but are not limited to, one or a combination of the load application range, frequency, number of cycles, etc.

[0091] The load application range refers to the upper and lower limits of the predefined load. For example, for a displacement load, the load application range is ±5 mm.

[0092] Frequency refers to the number of times the load is applied per unit time. The frequency can be determined based on the actual application requirements.

[0093] The preset fatigue limit number of times refers to the total number of times the displacement load is applied.

[0094] In some embodiments, the setting parameters can be determined based on experiments or experience.

[0095] Step 220, after the number of cycles of the in-line bar displacement reaches the preset number of times, determine the failure result of the bar through a withstand voltage test.

[0096] The number of cycles of displacement refers to the number of times the displacement load has been applied during the fatigue test.

[0097] The preset number of times refers to the preset number of cycles in the fatigue test. For example, the preset number of times can include 10,000 times, 100,000 times, 200,000 times, etc.

[0098] In some embodiments, the control device can be communicatively connected to the withstand voltage test device, and based on the test parameters, control the withstand voltage test device to apply an AC voltage higher than the rated voltage by a certain proportion to the bar for a period of time (such as 1 minute), and detect whether there is insulation breakdown or leakage in the bar.

[0099] Step 230, based on the failure results after the number of cycles of the bar displacement reaches different preset numbers of times, determine the fatigue test curve of the generator bar.

[0100] The fatigue test curve characterizes the relationship between the displacement of the bar and the number of cycles.

[0101] The failure result refers to the result of the time-dependent evaluation of the bar under different preset loads and different numbers of cycles during the fatigue test.

[0102] The fatigue test curve is used to represent the curve relationship between the displacement amount and the number of cycles allowed before the bar reaches fatigue failure. In some embodiments, the fatigue test curve can be obtained by fitting based on experimental data. The abscissa of the fatigue test curve is the number of cycles, usually presented in logarithmic coordinates, and the ordinate is the displacement amount. The fitting algorithm can include the least squares method, the Levenberg-Marquardt algorithm, the genetic algorithm, etc.

[0103] In some embodiments, a displacement sensor and a strain gauge can be installed on the bar to obtain the displacement amount or stress of the bar. Among them, the displacement sensor can be installed at the position of the maximum displacement or deformation of the bar. The strain gauge can be installed in the area of the maximum stress change of the bar.

[0104] The fatigue test curve can intuitively display the fatigue life of the bar under different displacement amounts, helping users (such as engineers) select appropriate materials and optimize the structural design during the design phase.

[0105] In some embodiments of this specification, through the fatigue test curve, the life of the bar in actual use can be predicted, which helps to specify a reasonable maintenance and replacement plan and extend the overall service life of the generator; by gradually increasing the number of cycles and conducting a voltage withstand test, key data can be obtained in a shorter time, reducing the cost and resource consumption of long-term continuous testing.

[0106] In some embodiments, the failure result of the bar is determined through a voltage withstand test, including:

[0107] Applying a voltage to the bar based on a preset starting voltage;

[0108] Increasing the voltage applied to the bar until the voltage applied to the bar reaches a preset full-value voltage;

[0109] After the time of applying the preset full-value voltage reaches a preset duration, reducing the voltage applied to the bar to determine the failure result of the bar according to whether there is a preset failure phenomenon in the bar.

[0110] The preset starting voltage refers to the voltage value initially applied to the bar at the start of the voltage withstand test.

[0111] The preset full-value voltage refers to the highest voltage value that ultimately needs to be applied to the bar during the voltage withstand test.

[0112] The preset starting voltage and the preset full-value voltage can be determined based on historical data or prior knowledge. For example, the preset starting voltage is 10% to 20% of the rated voltage.

[0113] In some embodiments, the control device can control the voltage withstand device to start from the preset starting voltage and gradually increase the voltage applied to the bar until the preset full-value voltage is reached. After each voltage increase, maintain a specified time (such as a few seconds) and detect the failure result of the bar. After the voltage applied to the bar reaches the preset full-value voltage, maintain this preset full-value voltage for a predetermined time (such as 1 minute or longer, which can be determined according to standards or design requirements), detect the failure result of the bar. After maintaining the preset full-value voltage for the predetermined time, gradually reduce the voltage to a preset value (such as 50% of the preset full-value voltage), and control the voltage withstand device to cut off the power.

[0114] The preset failure phenomenon refers to the fatigue failure conditions that may occur when the bar bears a high voltage. For example, the preset failure phenomenon can include, but is not limited to, breakdown, leakage, corona, flashover and other phenomena.

[0115] In some embodiments, the control device may be communicatively connected to the monitoring device, and based on the monitoring device detecting changes in parameters such as the voltage and current of the wire bar, determine the failure result of the wire bar. For example, when a current greater than a preset current threshold suddenly appears in the wire bar after applying a voltage, it is determined that a breakdown phenomenon occurs. Another example is that based on the image of the wire bar collected by the image acquisition device, when blue light appears in a dark background or obvious arcs or sparks exist, it is confirmed that phenomena such as corona or flashover occur.

[0116] In some embodiments, determining the failure result of the wire bar according to whether there is a preset failure phenomenon in the wire bar includes:

[0117] When it is determined that there is a breakdown phenomenon and / or a flashover phenomenon in the wire bar, determine that the failure result of the wire bar is fatigue failure.

[0118] In some embodiments of this specification, by gradually increasing from a lower preset starting voltage to a preset full-value voltage, it is possible to ensure that preset failure phenomena in the wire bar are discovered in a timely manner, avoiding equipment damage or operator risks caused by suddenly applying a high voltage; after reaching the preset full-value voltage and maintaining for a predetermined time (such as 1 minute), it is possible to simulate the high-voltage stress that the wire bar endures for a long time under actual operating conditions, and further verify the insulation performance of the wire bar.

[0119] In some embodiments, the method further includes:

[0120] Determine the test parameters of the withstand voltage test based on the operating parameters of the wire bar, where the test parameters include at least one of a preset full-value voltage, a preset starting voltage, a boosting duration, and a voltage frequency.

[0121] The operating parameters of the wire bar refer to the characteristics of the wire bar under normal operating conditions. For example, the operating parameters of the wire bar may include, but are not limited to, rated voltage, rated current, frequency, etc.

[0122] The test parameters refer to the specific parameters that need to be set when conducting the withstand voltage test.

[0123] In some embodiments, the test parameters are determined based on the operating parameters of the wire bar and with reference to relevant standards or specifications. For example, according to the rated voltage and relevant standards, usually a preset multiple (such as 2 times or a higher value, etc.) of the rated voltage is selected as the preset full-value voltage.

[0124] The preset starting voltage can be determined based on experiments or experience. For example, the preset starting voltage is a value 50% lower than the preset full-value voltage.

[0125] The boosting duration refers to the duration maintained after increasing to the preset full-value voltage.

[0126] The voltage frequency refers to the frequency of the applied voltage. For the AC withstand voltage test, the voltage frequency can be the power frequency (such as 50 Hz or 60 Hz).

[0127] Exemplarily, the withstand voltage test includes: setting the voltage frequency to 45 Hz to 65 Hz. The preset starting voltage applied during the withstand voltage test starts from not exceeding half of the preset full value voltage, and the withstand voltage device is controlled to gradually increase to the preset full value voltage evenly or in increments of not more than 5% of the preset full value voltage per step. The time from the preset starting voltage to the preset full value voltage should be not less than 10 s. At the preset full value voltage, the predetermined time should last for 1 min, and then the withstand voltage device is controlled to quickly reduce the voltage applied to the wire bar to below 50% of the preset full value voltage, and the withstand voltage device is controlled to disconnect the power supply;

[0128] In some embodiments, the high-voltage test wiring is suspended, and the high-voltage lead is made of copper wire with a diameter of Φ1.0 mm or more or a high-voltage cable to reduce corona. When multiple wire bars are subjected to fatigue tests together, when placing the wire bars, the ends of the low-resistance corona-resistant layers of the slot parts of the wire bars should be aligned, and the distance between the wire bars should be not less than 100 mm.

[0129] In some embodiments, the preset full value voltage is set according to the actual project requirements.

[0130] In some embodiments of this specification, by reasonably setting these test parameters, the insulation performance and reliability of the wire bar can be comprehensively evaluated.

[0131] Figure 3 is an exemplary flowchart for determining the fatigue test curve according to some embodiments of this specification. In some embodiments, process 300 can be executed based on a control device. As Figure 3 shown, process 300 includes the following steps.

[0132] In some embodiments, based on the failure results after the number of cycles of the wire bar displacement reaches different preset numbers, determining the fatigue test curve of the generator wire bar includes:

[0133] Step 310, for each preset load, based on the failure results after the number of cycles of the wire bar displacement under the preset load reaches different preset numbers, taking the number of cycles when the failure result is fatigue failure as the failure number;

[0134] Step 320, determining the displacement amount of the wire bar corresponding to the failure number;

[0135] Step 330, based on the displacement amount corresponding to each failure number, determining the fatigue test curve of the wire bar; the fatigue test curve includes the correlation between the displacement amounts of multiple wire bars and the failure numbers.

[0136] The preset load refers to the load that is preset and applied to the busbar during the fatigue test. The preset load can be a preset displacement load.

[0137] In some embodiments, for each preset load, the control device can control the load application device to cyclically apply the preset load to the busbar. When the number of cycles of the preset load applied to the busbar reaches the preset number, the failure result of the busbar is determined through a withstand voltage test. When the failure result is a fatigue failure (such as when there is a breakdown phenomenon and / or a flashover phenomenon in the busbar), the number of cycles is recorded as the failure number.

[0138] In some embodiments, the control device can be communicatively connected to a displacement sensor provided on the busbar to obtain the displacement of the busbar at the time of fatigue failure through the displacement sensor.

[0139] In some embodiments, based on the displacement corresponding to each failure number, the control device can obtain a fatigue test curve through a fitting algorithm. This fatigue test curve reflects the fatigue life (i.e., the number of fatigue cycles) of the busbar at different displacements.

[0140] Exemplarily, the preset load is a displacement load, and multiple different preset loads are selected to cover different situations from low displacement loads to high displacement loads. For example, the preset loads can include:

[0141] Preset load 1: ±1 mm;

[0142] Preset load 2: ±3 mm;

[0143] Preset load 3: ±5 mm;

[0144] Preset load 4: ±7 mm;

[0145] For each preset load, based on the loading frequency (such as 10 times per second), the control device controls the load application device to apply the preset load to the busbar to simulate the actual working conditions of the busbar.

[0146] For each preset load, multiple preset numbers (such as 10,000 times, 100,000 times, 200,000 times,..., 1,000,000 times, etc.) are set. For each of the multiple preset numbers, after the number of cycles reaches this preset number, the fatigue test is paused, and the failure result of the busbar at this preset number is determined by performing a withstand voltage test on the busbar. Whether the busbar shows a failure phenomenon (such as breakdown, flashover, etc.) is detected. If a failure occurs, the number of cycles is recorded as the failure number.

[0147] In some embodiments, the fatigue test can be carried out based on the grouped method or the up-and-down method.

[0148] In some embodiments of this specification, the displacement load is gradually increased from a low value to a high value to ensure comprehensive coverage of all possible failure phenomena; by identifying potential failure phenomena in advance, preventive maintenance measures can be taken to reduce the unexpected downtime and maintenance costs of the generator.

[0149] In some embodiments, the displacement of the coil bar is related to the applied load of the load application device;

[0150] Based on the failure results after the number of cycles of the coil bar displacement reaches different preset numbers, determine the fatigue test curve of the generator coil bar, including:

[0151] Determine the load application range of the load application device based on the preset fatigue limit number of the coil bar;

[0152] Based on the failure results after the number of cycles of the coil bar displacement within the load application range reaches different preset numbers, determine the fatigue test curve of the generator coil bar within the load application range.

[0153] In the fatigue test, the load application device is used to apply a periodically changing displacement to the coil bar. The load application device can accurately control parameters such as the magnitude and frequency of the displacement of the coil bar to simulate the dynamic loading conditions of the coil bar under actual working conditions.

[0154] The applied load refers to the force or load applied to the coil bar by the load application device. The applied load can be a displacement load.

[0155] In some embodiments, the displacement of the coil bar can be determined based on the applied load of the load application device. For example, the displacement load is used as the displacement of the coil bar, or the displacement of the coil bar is detected based on a displacement sensor installed on the coil bar.

[0156] The load application range refers to the change interval of the load applied by the load application device to the coil bar during the fatigue test. For example, the load application range can include all possible values from the minimum displacement to the maximum displacement, used to simulate different displacements or different forces that the coil bar may experience under actual working conditions.

[0157] In some embodiments, the preset fatigue limit number can be set according to actual design requirements.

[0158] Determining the load application range through the preset fatigue limit number can ensure that the experimental conditions cover the actual use conditions of the coil bar. This method can more accurately simulate the fatigue behavior of the coil bar during actual operation, thereby providing a reliable basis for evaluating its fatigue performance.

[0159] In some embodiments, under the preset fatigue limit number of times of the wire rod, the cyclic control of the sample wire rod movement is performed through the load application device until the failure result of the sample wire rod is fatigue failure, and the failure displacement amount when the sample wire rod generates fatigue failure is determined; based on the average value or minimum value of the failure displacement amounts when multiple sample wire rods generate fatigue failure, the maximum load and minimum load corresponding to the failure displacement amount are obtained to determine the load application range.

[0160] In some embodiments of the present specification, by determining the preset fatigue limit number of times and the load application range, unnecessary experiment times and time can be reduced. By focusing on the key displacement range and the number of cycles, the experiment can be completed more efficiently while reducing resource waste.

[0161] In some embodiments, during the process that the number of cycles of the wire rod displacement reaches different preset numbers, the preset numbers are determined based on the preset fatigue limit number of times.

[0162] In some embodiments, multiple preset numbers can be obtained based on the preset fatigue limit number of times through a preset division method (such as equal interval, non-equal interval division or other custom division methods, etc.), such as the first preset number, the second preset number, the third preset number, etc.

[0163] In some embodiments, the control device can determine multiple preset numbers based on the preset fatigue limit number of times of the wire rod through a preset rule. For example, the preset rule can be: the closer the number of cycles that the wire rod has displaced is to the preset fatigue limit number of times, the smaller the interval between two adjacent preset numbers.

[0164] In the fatigue test, there is a negative correlation between the interval between two adjacent preset numbers and the number of cycles that the wire rod has experienced. This means that as the number of cycles that the wire rod has experienced increases, the remaining number of cycles that it can withstand (i.e., the preset number) will decrease. This phenomenon reflects the cumulative damage effect of the material under repeated loading.

[0165] In some embodiments of the present specification, each cycle will cause minor damage to the material, and multiple damages will gradually accumulate, eventually leading to fatigue failure. By dynamically adjusting the preset number, the cumulative damage effect of the wire rod in actual use can be better simulated to analyze the fatigue damage accumulation situation of the material at different stages, which helps to accurately predict the life of the wire rod.

[0166] For the purpose of easy explanation, the end wire rod will be taken as an example for exemplary illustration hereinafter.

[0167] Figure 4 is an exemplary schematic diagram of the end wire rod shown according to some embodiments of the present specification.

[0168] In some embodiments, before conducting the fatigue test, according to the actual design drawings, the weak points of the generator rotor bars of the pumped-storage unit (such as the end bars) can be selected as the test objects. For example, the end bars for the test are fabricated, as Figure 4 shown; according to the structure and dimensions of the end bars, the clamping device for the test is fabricated; the clamping device is fixed, and the end bars are installed in the clamping device to ensure reliable fixation of the end bars; the load application device is fixed and fixedly connected to the end bars.

[0169] In some embodiments, except for the overhanging section, the end bars should be extended by a section into the iron core to facilitate the fixation of the bars by the fixture tooling and the subsequent AC withstand voltage test;

[0170] In some embodiments, after the end bars are fabricated, the end bars need to be inspected to ensure that the insulating medium of the end bars is not damaged, and there are no breakdown, flashover, etc. phenomena after the AC withstand voltage test is conducted on the end bars.

[0171] In some embodiments, the clamping device is clamped at the actual assembly position of the end bars, including the support points and the fixed points, and the clamping device has good stiffness at the same time to ensure the normal conduct of the test.

[0172] In some embodiments, the frequency and displacement of the load application device are adjustable, and the load application device has sufficient energy to make the end bars reach the preset displacement.

[0173] It should be noted that the position where the end bars are connected to the load device (such as Figure 4 the load application point shown) can be determined according to the actual structure, and the connected position can be selected at the position where the displacement deformation of the end bars is the largest. And the connection between the load application device and the end bars needs to be safe and reliable, and disconnection is not allowed during the test process.

[0174] In some embodiments, the control device can be used to: apply a load to the end bars of the generator through the load application device to make the bars generate displacement; after the number of cycles of the displacement of the end bars reaches the preset number, determine the failure result of the end bars through the withstand voltage test; based on the failure results after the number of cycles of the displacement of the end bars reaches different preset numbers, determine the fatigue test curve of the end bars of the generator.

[0175] For the specific implementation of each of the above operations, reference can be made to the previous embodiments, and details are not described herein again.

[0176] It should be noted that the above description of the process is only for illustration and explanation, and does not limit the scope of application of this specification. For those skilled in the art, various modifications and changes can be made to the process under the guidance of this specification. However, these modifications and changes are still within the scope of this specification.

[0177] Figure 5 It is a schematic structural diagram of an electronic device shown according to some embodiments of this specification.

[0178] An embodiment of the present application further provides an electronic device 500, as Figure 5 shown. The electronic device 500 may include: a processor 501 and a memory 502. The electronic device 500 may further include one or more of a multimedia component 503, an input / output (I / O) component 504, and a communication component 505. In this embodiment, the electronic device 500 may be a device for implementing the fatigue test method of the generator bar provided in this embodiment.

[0179] Among them, the processor 501 is used to control the overall operation of the electronic device 500 to complete all or part of the steps in the above-mentioned fatigue test method for generator bars. The memory 502 is used to store various types of data to support the operation of the electronic device 500. These data may include, for example, instructions for any application or method operating on the electronic device 500, as well as application-related data, such as contact data, sent and received messages, pictures, audio, video, and so on. The memory 502 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Read Only Memory (PROM), Read Only Memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disc. The multimedia component 503 may include a screen and an audio component. The screen can be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signal can be further stored in the memory 502 or sent through the communication component 505. The audio component also includes at least one speaker for outputting audio signals. The I / O component 504 provides an interface between the processor 501 and other interface modules, and the above-mentioned other interface modules can be a keyboard, a mouse, buttons, etc. These buttons can be virtual buttons or physical buttons. The communication component 505 is used for wired or wireless communication between the electronic device 500 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, Narrow Band Internet of Things (NB-IoT), Enhanced Machine Type Communication (eMTC), or other 5G, etc., or a combination of one or more of them, is not limited here. Therefore, the corresponding communication component 505 may include: a Wi-Fi module, a Bluetooth module, an NFC module, and so on.

[0180] In an exemplary embodiment, the electronic device 500 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components, and is used to execute the above-mentioned fatigue test method for generator bars.

[0181] In another exemplary embodiment, a computer-readable storage medium including program instructions is further provided. When the program instructions are executed by a processor, the steps of the above-mentioned fatigue test method for generator bars are implemented. For example, the computer-readable storage medium may be the above-mentioned memory 502 including program instructions, and the above-mentioned program instructions may be executed by the processor 501 of the electronic device 500 to implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application;

[0182] Or, when the instructions are executed by a computer, the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application are implemented or executed.

[0183] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

[0184] Among the embodiments, implementation manners, and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0185] The above are only the preferred embodiments of the present application, and do not impose any formal restrictions on the present application. Although in the embodiments of the present application, the descriptions of the various embodiments have their own emphases, for the parts not detailed in a certain embodiment, reference may be made to the relevant embodiments of other embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A fatigue test method for a generator bar, characterized in that, The method includes: Applying a load to the bar of the generator through a load applying device to cause displacement of the bar; After the number of cycles of displacement of the bar reaches a preset number, determining the failure result of the bar through a withstand voltage test; Based on the failure results after the number of cycles of displacement of the bar reaches different preset numbers, determining the fatigue test curve of the bar, where the fatigue test curve characterizes the correlation between the displacement amount and the number of cycles of the bar.

2. The method according to claim 1, wherein The determining the failure result of the bar through a withstand voltage test includes: Applying a voltage to the bar based on a preset starting voltage; Increasing the voltage applied to the bar until the voltage applied to the bar reaches a preset full value voltage; After the time of applying the preset full value voltage reaches a preset duration, reducing the voltage applied to the bar to determine the failure result of the bar according to whether there is a preset failure phenomenon in the bar.

3. The method according to claim 2, characterized in that, The determining the failure result of the bar according to whether there is a preset failure phenomenon in the bar includes: In response to the bar having a breakdown phenomenon and / or a flashover phenomenon, determining that the failure result of the bar is fatigue failure.

4. The method according to claim 1, wherein The method further includes: Determining the test parameters of the withstand voltage test based on the working parameters of the bar, where the test parameters include at least one of a preset full value voltage, a preset starting voltage, a pressurization duration, and a voltage frequency.

5. The method according to claim 1, characterized in that, The determining the fatigue test curve of the bar based on the failure results after the number of cycles of displacement of the bar reaches different preset numbers includes: For each preset load, based on the failure results after the number of cycles of displacement of the bar under the preset load reaches different preset numbers, taking the number of cycles when the failure result is fatigue failure as the failure number; Determining the displacement amount of the bar corresponding to the failure number; Based on the displacement amount corresponding to each failure number, determining the fatigue test curve of the bar; the fatigue test curve includes the correlation between the displacement amounts of multiple bars and the failure numbers.

6. The method according to claim 1, characterized in that, The displacement amount of the bar is related to the load applied by the load applying device; The determining the fatigue test curve of the bar based on the failure results after the number of cycles of displacement of the bar reaches different preset numbers includes: Determining the load application range of the load applying device based on the preset fatigue limit number of the bar; Based on the failure results after the number of cycles of displacement of the bar within the load application range reaches different preset numbers, determining the fatigue test curve of the bar within the load application range.

7. The method according to claim 1, wherein During the process that the number of cycles of displacement of the bar reaches different preset numbers, the preset number is determined based on the preset fatigue limit number.

8. A fatigue test system for a generator bar, characterized in that, The system includes: A clamping device for fixing the bar; A load applying device for applying a displacement load to the bar to cause displacement of the bar; A withstand voltage test device for applying a voltage to the bar; A control device is communicatively connected to the load applying device and the withstand voltage test device, The control device is configured to: Apply a load to the bar of the generator through the load applying device to cause displacement of the bar; After the number of cycles of the displacement of the coil bar reaches a preset number, the failure result of the coil bar is determined through a withstand voltage test; Based on the failure results after the number of cycles of the displacement of the coil bar reaches different preset numbers, a fatigue test curve of the coil bar is determined, and the fatigue test curve characterizes the correlation between the displacement amount and the number of cycles of the coil bar.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the fatigue test method for a generator coil bar according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that, Comprising: a memory storing a computer program thereon; a processor configured to execute the computer program in the memory to implement the fatigue test method for a generator coil bar according to any one of claims 1 to 7.

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