Epoxy potting equipment insulation pre-evaluation method and system based on defect development speed

Abstract

The invention discloses an epoxy potting equipment insulation pre-evaluation method and system based on defect development speed, and belongs to the field of power equipment partial discharge detection.The epoxy potting equipment insulation pre-evaluation method comprises the steps that a sample with an epoxy resin defect with a bubble defect, a crack defect and a delamination defect is collected; carrying out long-time partial discharge test on different epoxy resin defect samples, and recording discharge characteristic quantities under different pressurization time; and comparing the discharge characteristic quantities under different pressurization times, judging the discharge development speeds of different defects under the action of long-time discharge, and evaluating the insulation harmfulness according to the different discharge development speeds. According to the invention, during equipment insulation examination, most of equipment with obviously unqualified insulation can be quickly screened out, and equipment which has defects but still has the hope of being put into use can be identified; and on the other hand, the accuracy can be enhanced, an object is clear for subsequent evaluation, misjudgment is avoided, and the safety and reliability of a power system are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of partial discharge detection of power equipment, and particularly relates to an epoxy-encapsulated equipment insulation pre-evaluation method and system based on defect development speed. BACKGROUND

[0002] Epoxy-encapsulated insulation is widely used in many fields such as power, chemical industry, aerospace, automobile, and rail transportation, and effectively ensures the stable operation and technological progress of equipment in various industries. However, in the standard process of epoxy encapsulation, although a key step of vacuum degassing is specially set to remove the gas components inside the material to the greatest extent, the presence of defects such as bubbles still cannot be fundamentally avoided. The internal stress caused by the shrinkage of epoxy resin curing, the thermal expansion and contraction stress caused by sudden changes in environmental temperature, and the mechanical impact and vibration of operation, all of which are superimposed, can also cause cracks in the epoxy-encapsulated insulation. In addition, if the interface is contaminated, the adhesion is reduced, the selected materials do not match each other, the shrinkage difference is too large, or the curing process is deviated and the adhesion is not complete, the epoxy-encapsulated insulation is also likely to have delamination defects. The presence of these defects poses a significant threat to the performance and reliability of epoxy-encapsulated insulation. However, when there are defects inside the equipment, it does not mean that the equipment cannot be used. If the insulation requirement of the equipment is not high and the risk of the defect is low, the equipment with defects can still be used after further risk assessment, thereby achieving effective use of resources and maximizing the value of the equipment.

[0003] In the current operating environment of the power system, the insulation evaluation of power equipment faces a series of complex and urgent problems. When evaluating the insulation of many power equipment, it is common to detect partial discharge (PD) signals caused by internal defects of the equipment. However, the presence of such partial discharge signals does not necessarily mean that the equipment cannot be used. However, if all power equipment with discharge signals caused by defects are analyzed in detail, it will encounter great difficulties. The number of power equipment is extremely large, and from the human aspect, it requires a large number of professional detection personnel to work for a long time. In addition, individual analysis will significantly prolong the entire insulation evaluation period, seriously affecting the debugging plan of power equipment and the normal construction progress of the power system. Currently, there is a lack of research on the damage caused by different epoxy resin defects to the insulation of the material. Past research has focused on the correlation between bubble defect size and insulation life and the relationship between insulation degradation and chemical reaction based on chemical analysis of the surface of the cavity deteriorated by partial discharge. However, there is a lack of research on the relationship between defect type and insulation life, especially in the presence of continuous partial discharge. SUMMARY

[0004] In view of the above problems, the present application is proposed.

[0005] Therefore, the technical problem solved by the present application is how to quickly and accurately evaluate the insulation hazard of different defect types (bubble, crack, delamination) in epoxy-filled power equipment under long-term discharge to realize efficient pre-screening and grading of equipment insulation performance.

[0006] To solve the above technical problems, the present application provides the following technical scheme: an epoxy-filled equipment insulation pre-evaluation method based on defect development speed, which comprises the following steps,

[0007] Collecting epoxy resin defect samples with bubble defects, crack defects and delamination defects; performing long-time partial discharge tests on different epoxy resin defect samples, recording discharge characteristic quantities under different pressurization times; comparing discharge characteristic quantities under different pressurization times to judge the discharge development speed of different defects under long-time discharge, and evaluating insulation hazard according to different discharge development speeds.

[0008] As a preferred scheme of the epoxy-filled equipment insulation pre-evaluation method based on defect development speed, the sample includes, for each defect, two defect sizes are selected respectively, the bubble defect is set to a diameter range, the crack defect is set to a width and depth range, and the delamination defect is set to a delamination depth and delamination area range.

[0009] As a preferred scheme of the epoxy-filled equipment insulation pre-evaluation method based on defect development speed, the partial discharge test includes setting a power frequency alternating current as an external voltage, and performing stepwise voltage rise during the test until there is a partial discharge signal in each cycle of the alternating voltage.

[0010] At the same time, the current voltage size is taken as the reference voltage of the discharge test.

[0011] As a preferred scheme of the epoxy-filled equipment insulation pre-evaluation method based on defect development speed, the discharge characteristic quantity includes a maximum discharge amplitude, a discharge frequency and an average discharge amplitude.

[0012] As a preferred scheme of the epoxy-filled equipment insulation pre-evaluation method based on defect development speed, the discharge development speed includes a first comparison method and a second comparison method.

[0013] The first comparison method judges whether there is a change in the sample before and after the experiment.

[0014] If there is a change before and after the reaction, it means that the defect type is dangerous, and if there is no change, the change of the discharge characteristic quantity is compared by the second comparison method.

[0015] As a preferred scheme of the method for pre-evaluating the insulation of the epoxy-filled equipment based on the defect development speed, wherein: the discharge development speed further comprises: normalizing the maximum discharge amplitude, discharge frequency and average discharge amplitude under different pressurization times, and comparing whether the discharge characteristic quantity increases before and after the reaction.

[0016] If there is an increasing trend, it means that the current defect type is dangerous;

[0017] If there is no increasing trend, it means that the current defect type is low in danger.

[0018] As a preferred scheme of the method for pre-evaluating the insulation of the epoxy-filled equipment based on the defect development speed, wherein: the evaluation of insulation hazard comprises: when the epoxy-filled insulation power equipment is subjected to insulation examination, if it is judged that the current equipment contains a defect type with high danger, the current equipment does not need to be further examined and can be confirmed as unable to be put into use;

[0019] If it is judged that the current equipment only contains a defect type with low danger, the current equipment is still expected to be put into use and is allowed to be further examined.

[0020] Another object of the present application is to provide a system for pre-evaluating the insulation of the epoxy-filled equipment based on the defect development speed.

[0021] To solve the above technical problems, the present application provides the following technical scheme: a system for pre-evaluating the insulation of the epoxy-filled equipment based on the defect development speed, comprising: a defect sample collection and preparation module, a partial discharge test and analysis module, and an insulation hazard evaluation module.

[0022] The defect sample collection and preparation module is responsible for collecting epoxy resin samples with bubble defects, crack defects and delamination defects, collecting defect samples of different specifications according to the preset defect size range, and ensuring that typical defect types and sizes are covered.

[0023] The partial discharge test and analysis module applies an alternating current voltage to the sample, adopts a step-by-step voltage boosting method until a stable partial discharge signal is detected, and records the reference voltage; the discharge characteristic quantity under different pressurization times is monitored for a long time, and the data is normalized; the discharge development speed of the defect is calculated by the first comparison method and the second comparison method.

[0024] The insulation hazard assessment module judges the risk degree of the defect type according to the discharge development speed result, and outputs a pre-evaluation conclusion; if the equipment has defects with high risk degree, it is directly determined that the equipment cannot be put into use; if only defects with low risk degree are contained, further examination is allowed.

[0025] The application provides a computer device, comprising a memory and a processor, and the memory stores a computer program, characterized in that the processor implements the steps of the insulation pre-evaluation method of the epoxy pouring equipment based on defect development speed when executing the computer program.

[0026] The application provides a computer readable storage medium, which stores a computer program, characterized in that the computer program implements the steps of the insulation pre-evaluation method of the epoxy pouring equipment based on defect development speed when executed by a processor.

[0027] The application has the beneficial effects that the application judges the risk degree of three defects, i.e., bubbles, cracks and delamination, on insulation from the perspective of the discharge development speed of defects under continuous discharge, proposes the insulation pre-evaluation method of the epoxy pouring equipment based on defect development speed, and realizes the rapid screening of most obviously unqualified equipment in insulation examination and the identification of equipment with defects but still with hope of being put into use. The rapid screening of most obviously unqualified equipment in insulation examination and the identification of equipment with defects but still with hope of being put into use have extremely crucial significance. On the one hand, the examination efficiency can be improved, obviously unqualified equipment can be quickly found, the examination resources can be focused on the hopeful equipment, the process can be accelerated, and the power project can be ensured to be promoted on time. On the other hand, the accuracy can be improved, the object for subsequent evaluation can be clearly determined, misjudgment can be avoided, and the safety and reliability of the power system can be ensured. By distinguishing equipment with different insulation states, the power enterprise can more reasonably arrange the maintenance, maintenance, replacement or continuous use plan of the equipment. The obviously unqualified equipment is timely processed, the equipment with defects but can be used is subjected to targeted maintenance and monitoring, the potential of the equipment is fully tapped, the overall utilization rate of the equipment is improved, the equipment purchase cost and operation cost are reduced, and the economic benefit and competitiveness of the power enterprise are improved as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0029] Figure 1 The application provides a computer readable storage medium, which stores a computer program, characterized in that the computer program implements the steps of the insulation pre-evaluation method of the epoxy pouring equipment based on defect development speed when executed by a processor.

[0030] Figure 2 The three defect samples of bubble, crack and delamination of the epoxy resin are provided for the pre-evaluation method of the insulation of the epoxy potting equipment based on the defect development speed.

[0031] Figure 3 The long-time partial discharge test platform is provided for the pre-evaluation method of the insulation of the epoxy potting equipment based on the defect development speed.

[0032] Figure 4 The post-experiment crack defect sample and the pre-experiment and post-experiment X-ray result comparison chart are provided for the pre-evaluation method of the insulation of the epoxy potting equipment based on the defect development speed.

[0033] Figure 5 The bubble and crack defect discharge characteristic quantity normalization result is provided for the pre-evaluation method of the insulation of the epoxy potting equipment based on the defect development speed. DETAILED DESCRIPTION

[0034] In order to make the above objectives, characteristics and advantages of the present application more apparent, obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0035] Embodiment 1, refer to Figure 1 The pre-evaluation method of the insulation of the epoxy potting equipment based on the defect development speed is provided for the first embodiment of the present application, which comprises:

[0036] S1, collecting the epoxy resin defect samples with bubble defects, crack defects and delamination defects.

[0037] It should be noted that two defect sizes are selected for each defect respectively, the bubble defect is set to a diameter range, the crack defect is set to a width and depth range, and the delamination defect is set to a delamination depth and delamination area range.

[0038] Specifically, the epoxy resin defect sample is a cylinder with a diameter of 34 mm and a height of 2.5 mm. Two defect sizes are selected for each defect, the bubble defect is approximately spherical, and the diameter is about 1 mm and 2 mm respectively;

[0039] The width of the crack defect is about 2-10 μm, and the depth is about 1 mm and 1.5 mm respectively;

[0040] The delamination depth of the delamination defect is about 20 μm, and the delamination area is about 1 cm and 2 cm respectively2 .

[0041] S2, long-time partial discharge tests are performed on different epoxy resin defect samples, and discharge characteristic quantities under different pressurization times are recorded.

[0042] It should be noted that, in an embodiment of the present application, the partial discharge test uses a high-frequency current transformer (HFCT) to collect the partial discharge signal, with a frequency band of 60 kHz-120 MHz and a conversion ratio of 5 V / A.

[0043] The power frequency alternating current is set as the external voltage, and during the test, the voltage is stepped up until there is a partial discharge signal in each cycle of the alternating voltage; wherein the different pressurization times are 1 minute, 30 minutes, 60 minutes, 90 minutes, 120 minutes and 150 minutes.

[0044] At the same time, the current voltage size is taken as the reference voltage of the discharge test.

[0045] It should also be noted that the discharge characteristic quantity includes the maximum discharge amplitude, the discharge frequency, and the average discharge amplitude.

[0046] In an optional embodiment, the partial discharge test can be based on HFCT collection and increase the ultrasonic sensor array, which is arranged around the sample at 5 mm, with a frequency band set to 40-200 kHz, and a time synchronization controller is used to coordinate the HFCT and the ultrasonic sampling to ensure that the timestamps of the two data are aligned. When the HFCT detects a discharge signal, the ultrasonic sensor is triggered synchronously to record the sound wave signal. The ultrasonic signal is subjected to time-frequency analysis to extract the sound emission peak value and duration characteristics. The electric-acoustic characteristics are combined into a three-dimensional feature vector (electric amplitude + electric frequency + acoustic energy).

[0047] In another optional embodiment, the partial discharge test can also be to change the original wideband HFCT to a dual-channel configuration: a low-frequency channel (60 kHz-1 MHz) and a high-frequency channel (1-120 MHz); a digital filter is used to perform real-time separation processing on the signals of the two channels; the low-frequency channel focuses on recording the discharge repetition rate and phase distribution; the high-frequency channel captures the nanosecond-level pulse waveform front feature; and the time-domain correlation analysis of the data of the two channels is realized through FPGA.

[0048] S3, compare the discharge characteristic quantities under different pressurization times to determine the discharge development speed of different defects under long-time discharge action, and evaluate the insulation hazard according to the different discharge development speeds.

[0049] Furthermore, the first comparison method and the second comparison method are used;

[0050] The first comparison method determines whether there is a change in the sample before and after the test;

[0051] If there is a change before and after the reaction, it means that the defect type is dangerous, and if there is no change, the change of the discharge characteristic quantity is compared by the second comparison method.

[0052] The second comparison method normalizes the maximum discharge amplitude, discharge frequency and average discharge amplitude under different pressurization times, and compares whether the discharge characteristic quantity increases before and after the reaction;

[0053] If there is an increasing trend, it means that the current defect type is dangerous;

[0054] If there is no increasing trend, it means that the current defect type is low in danger.

[0055] Specifically, the normalization processing method is:

[0056]

[0057] Wherein, x1 is the discharge characteristic quantity when pressurized for one minute, x i is the discharge characteristic quantity when pressurized for i minutes, and the value range of i is 1, 30, 60, 90, 120 and 150.

[0058] Two or more of the three discharge characteristic quantities increase with the increase of pressurization time, and the normalized result at 150 minutes of pressurization is greater than 20%.

[0059] Further, when the epoxy pouring insulation power equipment is subjected to insulation test, if it is judged that the current equipment contains a defect type with high danger degree, the current equipment does not need to be further tested and can be confirmed as unable to be put into use;

[0060] If it is judged that the current equipment only contains a defect type with low danger degree, the current equipment is still expected to be put into use and is allowed to be further tested.

[0061] To sum up, the present application first prepares three kinds of epoxy pouring micro-defects that are consistent with the actual situation, collects the discharge data of the three kinds of micro-defects under the action of continuous discharge using HFCT, and obtains the discharge development speed of the three kinds of epoxy pouring micro-defects by comparing the macro changes of the defects before and after the experiment, the changes of the maximum discharge amplitude, discharge frequency and average discharge amplitude under different pressurization times, and further judges the insulation hazard of the three kinds of defects, and finally realizes the insulation pre-evaluation of the epoxy pouring equipment based on the defect development speed. In summary, the method helps to quickly screen out most of the equipment with obvious unqualified insulation, and identify the equipment with defects but still have hope to put into use. The rapid screening and accurate identification can on the one hand improve the examination efficiency, focus the examination resources on the equipment with hope, speed up the process, and ensure the timely progress of the power project; on the other hand, it can enhance the accuracy, clarify the object for subsequent evaluation, avoid misjudgment, and ensure the safety and reliability of the power system; it can also optimize the resource allocation, reasonably arrange the equipment processing plan, tap the potential of the equipment, reduce the cost, and improve the enterprise benefit and competitiveness.

[0062] Embodiment 2, refer to Figure 2 and Figure 5 , the present application provides a method for pre-evaluation of the insulation of epoxy pouring equipment based on the defect development speed, in order to verify the beneficial effects of the present application, scientific demonstration is carried out through experiment.

[0063] The epoxy resin bubble, crack and delamination three kinds of defect samples are as Figure 2 shown. The figure shows the epoxy resin micro-defect samples used in the experiment. For each type of defect, samples of large and small sizes are selected for the experiment, among which A and B are bubble defects, C and D are crack defects, and E and F are delamination defects, a total of six groups of samples. The shape of the defect sample is a flat cylinder with a diameter of about 3.4 cm and a height of about 2.5 mm.

[0064] Figure 3An experimental setup of partial discharge (PD) test and acquisition system is presented. In order to avoid the occurrence of surface discharge during the experiment, the epoxy resin defect samples and electrodes are immersed in transformer oil. The transformer oil can also provide a good heat dissipation environment for the samples. The plate-plate electrode structure is used in the experiment, and the sample is clamped between the electrodes. In order to measure the partial discharge current pulse, a broadband high-frequency current transformer (HFCT, frequency range 60 kHz to 120 MHz, conversion ratio 5 V / A) is installed around the ground wire, and the partial discharge signal is acquired by a multi-channel high-speed data acquisition card. In this test, a 50 Hz / 150 kV corona-free AC transformer is used as the high-voltage power supply. During the experiment, the voltage is gradually increased until a relatively strong discharge signal appears in the defect. Thereafter, the applied voltage remains unchanged. The discharge conditions at 1 minute, 30 minutes, 60 minutes, 90 minutes, 120 minutes and 150 minutes are recorded respectively.

[0065] For crack defects, it is observed that samples C and D are broken down within 30 minutes under the action of continuous partial discharge. Figure 4 The damaged crack samples and the X-ray images before and after breakdown are presented. By comparing Figure 4 (b) and Figure 4 (c), it can be found that under the condition of continuous partial discharge, the crack in the epoxy resin expands rapidly and eventually forms a through channel. In contrast, for bubble and delamination defects, there is no obvious macroscopic change in the samples before and after the experiment. Therefore, it can be concluded that under the influence of continuous partial discharge, the crack defect develops the fastest and poses the greatest threat to insulation.

[0066] In order to further compare the development speed of bubble defect and delamination defect discharge, the discharge statistical data is normalized. The normalization method is to calculate the growth rate of the maximum discharge amplitude, discharge frequency and average discharge amplitude relative to 1 minute under different applied voltage times, and the calculation formula is as follows

[0067]

[0068] where x1 is the discharge characteristic quantity at 1 minute, x i is the discharge characteristic quantity at i minutes, and i takes the values 1, 30, 60, 90, 120 and 150. The normalization results are shown in Figure 5 . In the figure, "max" represents the maximum discharge amplitude, "avg" represents the average discharge amplitude, and "freq" represents the discharge frequency.

[0069] From Figure 5It can be seen that after 150 minutes of applied voltage, the maximum discharge amplitude, discharge frequency and average discharge amplitude of sample A remain substantially stable. For sample B, its maximum discharge amplitude does not substantially change, however, its discharge frequency increases by about 10% and its maximum discharge amplitude decreases by about 40% compared to the case when the voltage is applied for 1 minute. As for sample E, its maximum discharge amplitude, discharge frequency and average discharge amplitude increase by about 20% compared to the case when the voltage is applied for 1 minute. For sample F, when the applied voltage lasts for 150 minutes, its maximum discharge amplitude, discharge frequency and average discharge amplitude increase by 80%, 110% and 30% respectively compared to the case when the voltage is applied for 1 minute.

[0070] In summary, under the action of continuous partial discharge, the internal partial discharge intensity of the sample presents a slow increasing trend, and with the continuous passage of time, this increasing trend becomes more and more significant. In contrast, the internal partial discharge intensity of the bubble defect tends to be stable or even slightly decreases during the development process.

[0071] Therefore, from the perspective of the development speed of discharge intensity, it can be seen that the discharge development speed of the delamination defect is faster than that of the bubble defect. Under the action of continuous partial discharge, the discharge development speeds of the three epoxy resin defects are as follows: the crack defect develops the fastest, the delamination defect is the second, and the bubble defect is the slowest.

[0072] From the perspective of the development speed of the defect discharge, the insulation hazard of the three epoxy resin defects is in the order of crack defect > delamination defect > bubble defect.

[0073] Based on the discharge development speeds of the three epoxy resin defects, the present application proposes an insulation pre-evaluation method for epoxy potting equipment based on the development speed of defects. From the previous analysis, the hazard degree of the epoxy resin micro-defects can be classified as follows: the crack defect is the most dangerous, the delamination defect is the second, and the bubble defect is the last. Therefore, when performing insulation evaluation on the epoxy potted insulation equipment, if the discharge signal of the defect is detected, the type of the defect needs to be determined first. Since different types of defects have significantly different effects on insulation performance. When the defect type includes crack or delamination defect, these defects have a great negative impact on the insulation performance of the equipment. They can seriously damage the insulation structure or continuously cause the insulation performance to decrease. Therefore, it can be determined that the test sample cannot be put into use without further analysis.

[0074] If the defect type is a bubble defect, since the hazard degree of such defect is relatively low, and the long-term impact of the defect on the insulation performance needs to be determined by comprehensively considering multiple factors, the test sample needs to enter the next step of analysis.

[0075] For example, insulation life assessment can be performed to determine whether the defect will cause the insulation performance to degrade to an unacceptable level during operation of the device. This approach can quickly screen out most devices with obviously unacceptable insulation during device insulation testing and identify devices with defects but still have the hope of being put into use.

[0076] Embodiment 3, which is different from the first two embodiments, is a third embodiment of the present application.

[0077] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the technical solutions that essentially contribute to the prior art can be embodied in the form of software products. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the various embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0078] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered a list of executable instructions for implementing logic functions, and can be specifically embodied in any computer-readable medium for use by an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, apparatus, or device and execute the instructions, or in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by an instruction execution system, apparatus, or device, or in conjunction with these instruction execution systems, apparatus, or devices.

[0079] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer readable medium can be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example via an optical scanner, then compiled, interpreted or otherwise processed, as necessary, and stored in a computer memory.

[0080] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the embodiments described above, various steps or methods can be implemented, for example, by software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, and in another embodiment, any of the following techniques, which are well known in the art, can be used to implement the application: a hybrid of the techniques mentioned above; a combination of one or more of the techniques mentioned above; or one or more other techniques suitable for use in the computer-based systems described above.

[0081] Embodiment 4, which is a fourth embodiment of the present application, provides an epoxy encapsulation device insulation pre-evaluation system based on defect development speed, comprising: a defect sample collection and preparation module, a partial discharge test and analysis module, and an insulation hazard evaluation module;

[0082] The defect sample collection and preparation module is responsible for collecting epoxy resin samples with bubble defects, crack defects, and delamination defects, collecting defect samples of different specifications according to the preset defect size range (such as bubble diameter, crack width / depth, delamination area / depth), and ensuring coverage of typical defect types and sizes;

[0083] The partial discharge test and analysis module applies an alternating voltage to the sample, uses a step-by-step voltage boosting method until a stable partial discharge signal is detected, and records the reference voltage; monitors the discharge characteristic quantities (maximum discharge amplitude, discharge frequency, average discharge amplitude) at different pressurization times for a long time, and normalizes the data; calculates the discharge development speed of the defect through the first comparison method (judges the physical change of the sample) and the second comparison method (analyzes the trend of the discharge characteristic quantities);

[0084] The insulation hazard evaluation module judges the dangerous degree of the defect type according to the discharge development speed result, and outputs a pre-evaluation conclusion.

[0085] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application 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 application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A method for pre-assessing insulation of epoxy potting equipment based on defect development speed, characterized by: include, Collect specimens with epoxy resin defects such as bubble defects, crack defects and delamination defects; Long-term partial discharge tests were conducted on different epoxy resin defect samples, and the discharge characteristics at different pressurization times were recorded. By comparing the discharge characteristics under different pressurization times, the discharge development speed of different defects under long-term discharge is determined, and the insulation hazard is evaluated based on different discharge development speeds.

2. The epoxy potting equipment insulation pre-assessment method based on defect development speed according to claim 1, characterized in that: The sample includes two defect sizes for each defect selection: a bubble defect with a set diameter range, a crack defect with a set width and depth range, and a delamination defect with a set delamination depth and delamination area range.

3. The insulation pre-assessment method for epoxy potting equipment based on defect development speed according to claim 2, characterized in that: The partial discharge test includes setting power frequency alternating current as the external applied voltage, and stepping up the voltage in a stepwise manner until a partial discharge signal is present in each cycle of the alternating current voltage; At the same time, the current voltage is used as the reference voltage for the discharge test.

4. The insulation pre-assessment method for epoxy potting equipment based on defect development speed according to claim 3, characterized in that: The discharge characteristic quantities include maximum discharge amplitude, discharge frequency and average discharge amplitude.

5. The insulation pre-assessment method for epoxy potting equipment based on defect development speed according to claim 4, characterized in that: The discharge development speed includes using a first comparison method and a second comparison method; The first comparison method determines whether there are changes in the sample before and after the experiment; If there is a change before and after the reaction, it means that the risk level of this defect type is high. If there is no change, the change of the discharge characteristic quantity is compared through the second comparison method.

6. The insulation pre-assessment method for epoxy potting equipment based on defect development speed according to claim 4, characterized in that: The discharge development speed also includes normalizing the maximum discharge amplitude, discharge frequency, and average discharge amplitude under different pressurization times, and comparing whether the discharge characteristic quantity increases before and after the reaction; If there is an increasing trend, it means that the risk of the current defect type is high; If there is no increasing trend, it means that the risk of the current defect type is low.

7. The insulation pre-assessment method for epoxy potting equipment based on defect development speed according to claim 4, characterized in that: The insulation hazard assessment includes, when conducting insulation assessment on epoxy encapsulated insulation power equipment, if it is determined that the current equipment contains a high-risk defect type, then the current equipment can be confirmed to be unusable without further assessment; If it is determined that the current equipment only contains low-risk defect types, the current equipment is still expected to be put into use and further assessment is allowed.

8. An epoxy potting equipment insulation pre-assessment system based on defect development speed, applying the epoxy potting equipment insulation pre-assessment method based on defect development speed according to any one of claims 1 to 7, characterized in that: include: Defect sample collection and preparation module, partial discharge test and analysis module, and insulation hazard assessment module; The defect sample collection and preparation module is responsible for collecting epoxy resin samples with bubble defects, crack defects and delamination defects, and collecting defect samples of different specifications according to the preset defect size range to ensure that typical defect types and sizes are covered; The partial discharge testing and analysis module applies a power frequency AC voltage to the sample, using a step-by-step voltage boost method until a stable partial discharge signal is detected, and records the reference voltage; monitors the discharge characteristic quantities under different pressurization times for a long time, normalizes the data, and calculates the discharge development speed of the defect using the first comparison method and the second comparison method; The insulation hazard assessment module determines the hazard level of the defect type based on the discharge development speed results and outputs a preliminary assessment conclusion. If the equipment has defects with a high hazard level, it is directly determined that it cannot be put into use; if it only contains defects with a low hazard level, further assessment is allowed.

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 steps of the epoxy potting equipment insulation pre-assessment method based on defect development speed according to any one of claims 1 to 7 are implemented.

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 the method for pre-assessment of insulation of epoxy potting equipment based on defect development speed according to any one of claims 1 to 7 are implemented.

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