CVT capacitive voltage divider defect identification method and device, electronic equipment and storage medium

Abstract

The invention discloses a CVT capacitive voltage divider defect identification method and apparatus, an electronic device and a storage medium. The method comprises the steps of obtaining a secondary voltage waveform signal and infrared temperature measurement data of a CVT to be subjected to defect identification, and corresponding data of a reference CVT; judging whether voltage jump exists or not in combination with a preset time window and a voltage jump threshold value; analyzing whether external harmonic interference exists or not by using a harmonic content threshold value; judging whether the amplitude and the phase are abnormal or not based on the fundamental frequency voltage amplitude and the phase threshold; and the local overheating condition is detected through the abnormal overheating threshold value and the infrared temperature measurement data. And finally, under the condition of eliminating voltage abrupt change, harmonic interference, amplitude and phase anomalies, if local overheating anomalies exist, determining that capacitive voltage divider defects exist in the CVT. Otherwise, judging that no defect exists. According to the method, multi-dimensional comprehensive analysis is carried out, and the accuracy and efficiency of defect identification are improved. According to the invention, the diagnosis accuracy of the defects of the capacitive voltage divider can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fault identification, and in particular to a method, device, electronic equipment and storage medium for identifying defects of a CVT capacitor voltage divider. Background Art

[0002] Capacitor voltage transformer (hereinafter referred to as CVT) is an important device for voltage monitoring, relay protection, metering and measurement in power systems. The secondary voltage it outputs is directly related to the safe operation and control accuracy of the power system. However, due to the complex structure of CVT, especially its core component, the capacitor voltage divider, defects may occur during long-term operation due to insulation aging, abnormal electric field distribution and other reasons. This defect will change the transmission characteristics of CVT, resulting in secondary voltage distortion or deviation, so that the actual waveform of the system cannot be accurately reflected. When the defect worsens further, it may also cause relay protection malfunction or metering abnormality, bringing greater safety hazards. Therefore, how to accurately identify the defects of the capacitor voltage divider inside the CVT is of great significance to ensuring the reliability of the power system.

[0003] At present, the identification method for CVT capacitor divider defects mainly relies on the analysis of the effective value data of the secondary voltage amplitude, and compares it with historical data or the amplitude of the same-phase CVT in the station to determine whether there is a significant difference. However, the existing method relies too much on a single criterion and it is difficult to distinguish between capacitor divider defects and other factors that may cause voltage abnormalities (such as external short circuit, intermediate transformer failure, etc.), which is easy to cause misjudgment. Summary of the invention

[0004] The embodiment of the present invention provides a method, device, electronic device and storage medium for identifying defects of a CVT capacitor voltage divider. The implementation of the present invention can improve the accuracy of diagnosing defects of a CVT capacitor voltage divider.

[0005] An embodiment of the present invention provides a CVT capacitor voltage divider defect identification method, comprising:

[0006] Acquire the secondary voltage waveform signal of the CVT to be identified by defects, the infrared temperature measurement data of the CVT to be identified by defects, the secondary voltage waveform signal of the first CVT, and the infrared temperature measurement data of the second CVT; wherein the first CVT is a CVT that is connected to the same substation as the CVT to be identified by defects and has no defects; the second CVT is the first CVT that is not connected to the same bus as the CVT to be identified by defects but is in the same phase as the CVT;

[0007] Determine whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold, and a secondary voltage waveform signal of the CVT to be identified;

[0008] According to the preset harmonic content threshold and the secondary voltage waveform signal of the CVT to be identified, it is determined whether there is external harmonic interference in the CVT to be identified;

[0009] According to the preset fundamental frequency voltage amplitude threshold, the preset fundamental frequency phase threshold, the secondary voltage waveform signal of the CVT to be identified by defects, and the secondary voltage waveform signal of the first CVT, it is determined whether the CVT to be identified by defects has amplitude abnormality and phase abnormality;

[0010] According to the preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified as defective, and the infrared temperature measurement data of the second CVT, it is determined whether the CVT to be identified as defective has a local overheating abnormality;

[0011] If the CVT to be identified has local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality, it is determined that the CVT to be identified has a capacitor voltage divider defect; otherwise, it is determined that the CVT to be identified has no capacitor voltage divider defect.

[0012] Further, judging whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold and a secondary voltage waveform signal of the CVT to be identified, includes:

[0013] According to the preset time window, determine whether the voltage amplitude change of the secondary voltage waveform signal of the CVT to be identified within any time window exceeds the preset voltage mutation threshold. If so, it is determined that the CVT to be identified has a voltage mutation; if not, it is determined that the CVT to be identified has no voltage mutation.

[0014] Furthermore, judging whether there is external harmonic interference in the CVT to be identified according to a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified, includes:

[0015] Perform Fourier transformation on the secondary voltage waveform signal of the CVT to be identified, and obtain the first spectrum information after Fourier transformation;

[0016] Extracting and generating the amplitude of each frequency component from the first spectrum information;

[0017] Calculate and generate the harmonic content of the CVT to be defect-identified according to the amplitude of each frequency component;

[0018] Determine whether the harmonic content of the CVT to be identified as defective exceeds a preset harmonic content threshold. If so, determine that the CVT to be identified as defective has external harmonic interference. If not, determine that the CVT to be identified as defective does not have external harmonic interference.

[0019] Furthermore, the harmonic content of the CVT to be identified is calculated by the following formula:

[0020]

[0021] Wherein, THD is the harmonic content of the CVT to be identified; V 1 is the amplitude of the fundamental frequency component; V i (i≠1) is the amplitude of the harmonic component numbered i; n is the sequence number of the harmonic component.

[0022] Further, judging whether the CVT to be identified as defective has abnormal amplitude and abnormal phase according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified as defective, and a secondary voltage waveform signal of the first CVT includes:

[0023] Extracting and generating the fundamental frequency voltage amplitude and the fundamental frequency phase of the CVT to be identified by the defect from the first frequency spectrum information; performing Fourier transformation on the secondary voltage waveform signal of the first CVT to obtain the second frequency spectrum information after Fourier transformation;

[0024] Extracting the fundamental frequency voltage amplitude and the fundamental frequency phase of the first CVT from the second frequency spectrum information;

[0025] Calculating the amplitude deviation between the fundamental frequency voltage amplitude of the CVT to be identified and the fundamental frequency voltage amplitude of the first CVT to generate a fundamental frequency voltage amplitude deviation;

[0026] Calculate the phase deviation between the fundamental frequency phase of the CVT to be identified and the fundamental frequency phase of the first CVT to generate a fundamental frequency phase deviation;

[0027] Determine whether the fundamental frequency voltage amplitude deviation exceeds a preset fundamental frequency voltage amplitude threshold value, if so, determine that the CVT to be identified for defects has an amplitude abnormality, if not, determine that the CVT to be identified for defects does not have an amplitude abnormality;

[0028] Determine whether the fundamental frequency phase deviation exceeds a preset fundamental frequency phase threshold. If so, determine that the CVT to be identified for defects has a phase abnormality. If not, determine that the CVT to be identified for defects does not have a phase abnormality.

[0029] Furthermore, the fundamental frequency voltage amplitude deviation is calculated by the following formula:

[0030]

[0031] Where ΔV is the fundamental frequency voltage amplitude deviation; V target V is the fundamental frequency voltage amplitude of the defect recognition CVT; temp is the fundamental frequency voltage amplitude of the first CVT;

[0032] The fundamental frequency phase deviation is calculated by the following formula:

[0033] Δφ=|φ target -φ temp |

[0034] Among them, Δφ is the fundamental frequency phase deviation; φ target is the fundamental frequency phase of the CVT to be identified; φ temp is the fundamental frequency phase of the first CVT.

[0035] Further, judging whether the CVT to be identified as defective has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified as defective, and the infrared temperature measurement data of the second CVT includes:

[0036] Extract the temperature of the key parts of the capacitor voltage divider of the CVT to be identified based on the infrared temperature measurement data of the CVT to be identified; extract the temperature of the key parts of the capacitor voltage divider of the second CVT based on the infrared temperature measurement data of the second CVT; wherein the key parts include the outer surface of the oil tank;

[0037] Calculating the temperature difference between the key part temperature of the CVT capacitor voltage divider to be defect-identified and the key part temperature of the second CVT capacitor voltage divider to generate a key part temperature deviation;

[0038] Determine whether the temperature deviation of key parts other than the outer surface of the fuel tank exceeds the preset abnormal overheating threshold and whether the temperature deviation of the outer surface of the fuel tank does not exceed the preset abnormal overheating threshold. If so, it is determined that the CVT to be identified as defective has local overheating abnormality; if not, it is determined that the CVT to be identified as defective does not have local overheating abnormality.

[0039] Based on the above method embodiment, the present invention provides a corresponding device embodiment.

[0040] An embodiment of the present invention provides a CVT capacitor voltage divider defect identification device, comprising: a defect diagnosis data acquisition module, a voltage mutation determination module, an external harmonic interference determination module, an amplitude abnormality and phase abnormality determination module, a local overheating abnormality determination module and a capacitor voltage divider defect determination module;

[0041] The defect diagnosis data acquisition module is used to acquire the secondary voltage waveform signal of the CVT to be identified, the infrared temperature measurement data of the CVT to be identified, the secondary voltage waveform signal of the first CVT and the infrared temperature measurement data of the second CVT; wherein the first CVT is a CVT connected to the same substation as the CVT to be identified and has no defects; the second CVT is the first CVT that is not connected to the same bus as the CVT to be identified but is in the same phase as the CVT;

[0042] The voltage mutation determination module is used to determine whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold and a secondary voltage waveform signal of the CVT to be identified;

[0043] The external harmonic interference determination module is used to determine whether the CVT to be identified has external harmonic interference according to a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified;

[0044] The amplitude abnormality and phase abnormality judgment module is used to judge whether the CVT to be identified by defects has amplitude abnormality and phase abnormality according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified by defects, and a secondary voltage waveform signal of the first CVT;

[0045] The local overheating abnormality determination module is used to determine whether the CVT to be identified has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified and the infrared temperature measurement data of the second CVT;

[0046] The capacitor voltage divider defect judgment module is used to determine that the CVT to be identified has a capacitor voltage divider defect when the CVT to be identified has a local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality; otherwise, it is determined that the CVT to be identified does not have a capacitor voltage divider defect.

[0047] Based on the above method embodiment, the present invention provides a corresponding electronic device embodiment.

[0048] An embodiment of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the CVT capacitor voltage divider defect identification method described in any one of the above method embodiments can be implemented.

[0049] Based on the above method item embodiments, the present invention provides a corresponding storage medium item embodiment.

[0050] An embodiment of the present invention provides a storage medium having a computer program stored thereon. When the computer program is executed by a processor, the CVT capacitor voltage divider defect identification method described in any one of the above method embodiments can be implemented.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The embodiment of the present invention provides a method, device, electronic device and storage medium for identifying defects of a CVT capacitor divider. The method obtains the secondary voltage waveform signal and infrared temperature measurement data of the CVT to be identified and the reference CVT, and combines multiple preset criteria (voltage mutation, harmonic interference, fundamental frequency amplitude and phase abnormality, and local overheating abnormality) to comprehensively analyze and judge the operating state of the CVT to be identified, thereby realizing accurate identification of the capacitor divider defect.

[0053] The present invention introduces secondary voltage waveform signals and infrared temperature measurement data to conduct a comprehensive analysis of the CVT, and jointly determines the defects of the CVT capacitor divider through multi-dimensional parameters such as voltage mutation, harmonic interference, amplitude and phase anomalies, and local overheating. This overcomes the limitation of the prior art that it relies too much on a single criterion and improves the diagnostic accuracy of capacitor divider defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of a CVT capacitor voltage divider defect identification method provided by an embodiment of the present invention.

[0055] Figure 2 It is a structural schematic diagram of a CVT capacitor voltage divider defect identification device provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] like Figure 1 As shown, an embodiment of the present invention provides a CVT capacitor voltage divider defect identification method, which at least includes the following steps:

[0058] Step S1, obtaining a secondary voltage waveform signal of a CVT to be defect-identified, infrared temperature measurement data of the CVT to be defect-identified, a secondary voltage waveform signal of a first CVT, and infrared temperature measurement data of a second CVT;

[0059] Specifically, the first CVT is a CVT that is connected to the same substation as the CVT to be identified for defects and has no defects; the second CVT is a first CVT that is not connected to the same bus as the CVT to be identified for defects but is in the same phase;

[0060] Step S2: Based on a preset time window, a preset voltage mutation threshold, and the secondary voltage waveform signal of the CVT to be defect-identified, determine whether there is a voltage mutation in the CVT to be defect-identified;

[0061] In a preferred embodiment, the determining whether there is a voltage mutation in the CVT to be defect-identified based on a preset time window, a preset voltage mutation threshold, and the secondary voltage waveform signal of the CVT to be defect-identified includes:

[0062] Based on the preset time window, determine whether the voltage amplitude change amount of the secondary voltage waveform signal of the CVT to be defect-identified within any time window exceeds the preset voltage mutation threshold. If so, determine that there is a voltage mutation in the CVT to be defect-identified; if not, determine that there is no voltage mutation in the CVT to be defect-identified.

[0063] Specifically, based on the preset time window, analyze the secondary voltage waveform signal of the capacitive voltage transformer (CVT) to be defect-identified period by period. The specific method is to calculate the voltage amplitude change amount of the signal within any time window and compare it with the preset voltage mutation threshold. If it is detected that within a certain time window, the voltage amplitude change amount exceeds the preset voltage mutation threshold, it is determined that there is a voltage mutation phenomenon in the CVT, indicating that its operating state may be abnormal and further diagnosis or treatment is required. On the contrary, if the voltage amplitude change amounts within all time windows do not exceed the preset threshold, it is determined that there is no voltage mutation in the CVT, indicating that its voltage waveform signal remains stable within the set time range and its operating state is normal. The research on the defects of capacitive voltage dividers has been slow, usually manifested as the influence on the secondary steady-state voltage waveform of the transformer. If there is an amplitude mutation, it is considered to be other defects of the flashover discharge nature rather than this type of defect. This method can sensitively capture the voltage fluctuation characteristics, avoid the risk of missed detection caused by traditional methods ignoring short-term drastic changes, thereby improving the recognition accuracy of voltage mutations and providing a reliable basis for subsequent defect analysis.

[0064] The preset time window can be 0.001 s. The preset voltage mutation threshold can be 2 V.

[0065] It should be noted here that in order to avoid inaccurate judgment of whether there is a voltage waveform mutation in the secondary voltage waveform signal due to too low a sampling rate. In a preferred embodiment, the sampling rate should not be lower than 5 MHz.

[0066] Step S3: Based on a preset harmonic content threshold and the secondary voltage waveform signal of the CVT to be defect-identified, determine whether there is external harmonic interference in the CVT to be defect-identified;

[0067] In a preferred embodiment, judging whether the CVT to be identified for defects has external harmonic interference based on a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified for defects includes:

[0068] Perform Fourier transformation on the secondary voltage waveform signal of the CVT to be identified, and obtain the first spectrum information after Fourier transformation;

[0069] Extracting and generating the amplitude of each frequency component from the first spectrum information;

[0070] Calculate and generate the harmonic content of the CVT to be defect-identified according to the amplitude of each frequency component;

[0071] Determine whether the harmonic content of the CVT to be identified as defective exceeds a preset harmonic content threshold. If so, determine that the CVT to be identified as defective has external harmonic interference. If not, determine that the CVT to be identified as defective does not have external harmonic interference.

[0072] What needs to be explained here is that the secondary voltage waveform signal of the capacitive voltage transformer (CVT) to be identified by defect is Fourier transformed to obtain the corresponding frequency domain information, that is, the first spectrum information after Fourier transform. By analyzing the first spectrum information, the amplitude of each frequency component can be extracted to reflect the energy distribution of the signal at different frequencies. According to the amplitude of each frequency component extracted, the total harmonic content (THD) is calculated, that is, the amplitude ratio of each harmonic component (such as second and third harmonics) to the fundamental component in the signal. Then, the calculated harmonic content is compared with the preset harmonic content threshold. If the harmonic content exceeds the threshold, it indicates that the secondary voltage signal of the CVT to be identified by defect is affected by external harmonic interference, which may be caused by power grid harmonic pollution or abnormal operation of external equipment. At this time, it is determined that the CVT has external harmonic interference; conversely, if the harmonic content does not exceed the threshold, it is determined that the CVT to be identified by defect does not have external harmonic interference, indicating that the signal harmonic component is within the normal range. The preset harmonic content threshold here can be 5%.

[0073] In addition, by analyzing harmonic characteristics through Fourier transform, it is not only possible to determine the presence of harmonic interference, but also to further analyze the main source frequency band of interference, providing a basis for fault location and grid optimization. This criterion verifies whether the secondary voltage signal measured by the CVT is affected by external harmonic interference by calculating the harmonic content and comparing it with the preset threshold. If high-frequency or non-power frequency harmonic components appear in the power grid, these harmonics may interfere with the transmission characteristics of the CVT, resulting in an error between the secondary voltage signal and the actual power frequency voltage. This error originates from external system problems rather than defects in the CVT itself. Therefore, this criterion is to eliminate the interference of external system factors and ensure the authenticity and reliability of CVT performance evaluation. This method improves the accuracy and reliability of harmonic interference detection, and helps to ensure the normal operation of the voltage transformer and the stability of the secondary voltage signal.

[0074] Specifically, the harmonic content of the CVT to be identified is calculated by the following formula:

[0075]

[0076] Wherein, THD is the harmonic content of the CVT to be identified; V 1 is the amplitude of the fundamental frequency component; V i (i≠1) is the amplitude of the harmonic component numbered i; n is the sequence number of the harmonic component.

[0077] Step S4, judging whether the CVT to be identified by the defect has an abnormal amplitude and an abnormal phase according to the preset fundamental frequency voltage amplitude threshold, the preset fundamental frequency phase threshold, the secondary voltage waveform signal of the CVT to be identified by the defect, and the secondary voltage waveform signal of the first CVT;

[0078] In a preferred embodiment, judging whether the CVT to be identified as defective has abnormal amplitude and abnormal phase according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified as defective, and a secondary voltage waveform signal of the first CVT includes:

[0079] Extracting and generating the fundamental frequency voltage amplitude and the fundamental frequency phase of the CVT to be identified by the defect from the first frequency spectrum information; performing Fourier transformation on the secondary voltage waveform signal of the first CVT to obtain the second frequency spectrum information after the Fourier transformation;

[0080] Extracting the fundamental frequency voltage amplitude and the fundamental frequency phase of the first CVT from the second frequency spectrum information;

[0081] Calculating the amplitude deviation between the fundamental frequency voltage amplitude of the CVT to be identified and the fundamental frequency voltage amplitude of the first CVT to generate a fundamental frequency voltage amplitude deviation;

[0082] Calculate the phase deviation between the fundamental frequency phase of the CVT to be identified and the fundamental frequency phase of the first CVT to generate a fundamental frequency phase deviation;

[0083] Determine whether the fundamental frequency voltage amplitude deviation exceeds a preset fundamental frequency voltage amplitude threshold value, if so, determine that the CVT to be identified for defects has an amplitude abnormality, if not, determine that the CVT to be identified for defects does not have an amplitude abnormality;

[0084] Determine whether the fundamental frequency phase deviation exceeds a preset fundamental frequency phase threshold. If so, determine that the CVT to be identified for defects has a phase abnormality. If not, determine that the CVT to be identified for defects does not have a phase abnormality.

[0085] Specifically, from the first spectrum information, the fundamental frequency voltage amplitude and fundamental frequency phase of the CVT to be identified are extracted as key characteristic parameters under power frequency conditions; at the same time, the secondary voltage waveform signal of the first CVT is Fourier transformed to obtain the second spectrum information after Fourier transformation, from which the fundamental frequency voltage amplitude and fundamental frequency phase of the first CVT are extracted as reference standards. Subsequently, the amplitude deviation between the fundamental frequency voltage amplitude of the CVT to be identified and the fundamental frequency voltage amplitude of the first CVT is calculated to generate the fundamental frequency voltage amplitude deviation, reflecting the amplitude consistency between the two. At the same time, the phase deviation between the fundamental frequency phase of the CVT to be identified and the fundamental frequency phase of the first CVT is calculated to generate the fundamental frequency phase deviation, which is used to analyze the phase synchronization between the two. Then, it is determined whether the fundamental frequency voltage amplitude deviation exceeds the preset fundamental frequency voltage amplitude threshold. If it exceeds, it is determined that the CVT to be identified has an amplitude abnormality, indicating that its transmission characteristics may be damaged and cannot accurately reflect the primary voltage amplitude; if it does not exceed, it is determined that there is no amplitude abnormality. Similarly, it is determined whether the fundamental frequency phase deviation exceeds the preset fundamental frequency phase threshold. If it exceeds, it is determined that the CVT to be identified has a phase abnormality, indicating that its phase transmission characteristics have deviated; if it does not exceed, it is determined that there is no phase abnormality. This method can effectively diagnose whether the transmission characteristics of the CVT to be identified have changed through accurate calculation and comparative analysis of the fundamental frequency amplitude and phase, and ensure the high-precision consistency of the transmitted voltage signal in amplitude and phase. At the same time, combined with the comprehensive judgment of multi-dimensional parameters, it can significantly improve the accuracy and reliability of defect identification and provide a scientific basis for power grid operation.

[0086] The preset fundamental frequency voltage amplitude threshold may be 5%; the preset fundamental frequency phase threshold may be 1°.

[0087] Specifically, the fundamental frequency voltage amplitude deviation is calculated by the following formula:

[0088]

[0089] Where ΔV is the fundamental frequency voltage amplitude deviation; V targetV is the fundamental frequency voltage amplitude of the defect recognition CVT; temp is the fundamental frequency voltage amplitude of the first CVT;

[0090] The fundamental frequency phase deviation is calculated by the following formula:

[0091] Δφ=|φ target -φ temp |

[0092] Among them, Δφ is the fundamental frequency phase deviation; φ target is the fundamental frequency phase of the CVT to be identified; φ temp is the fundamental frequency phase of the first CVT.

[0093] Step S5, judging whether the CVT to be identified as defective has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified as defective, and the infrared temperature measurement data of the second CVT;

[0094] In a preferred embodiment, judging whether there is a local overheating abnormality in the CVT to be identified according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified and the infrared temperature measurement data of the second CVT includes:

[0095] Extract the temperature of the key parts of the capacitor voltage divider of the CVT to be identified based on the infrared temperature measurement data of the CVT to be identified; extract the temperature of the key parts of the capacitor voltage divider of the second CVT based on the infrared temperature measurement data of the second CVT; wherein the key parts include the outer surface of the oil tank;

[0096] Calculating the temperature difference between the key part temperature of the CVT capacitor voltage divider to be defect-identified and the key part temperature of the second CVT capacitor voltage divider to generate a key part temperature deviation;

[0097] Determine whether the temperature deviation of key parts other than the outer surface of the fuel tank exceeds the preset abnormal overheating threshold and whether the temperature deviation of the outer surface of the fuel tank does not exceed the preset abnormal overheating threshold. If so, it is determined that the CVT to be identified as defective has local overheating abnormality; if not, it is determined that the CVT to be identified as defective does not have local overheating abnormality.

[0098] Specifically, based on the infrared temperature measurement data of the capacitor voltage divider (CVT) to be identified, the temperature data of the key parts of the CVT capacitor voltage divider must first be extracted. These key parts usually include the outer surface of the oil tank, insulating materials, wiring terminals, porcelain sleeves, etc., in order to fully evaluate their working conditions. At the same time, based on the infrared temperature measurement data of the second CVT, the temperature of the key parts of the second CVT capacitor voltage divider is extracted.

[0099] After the data extraction is completed, the key temperature differences of the two CVT capacitor dividers are analyzed. Specifically, the temperature difference between the key temperature of the CVT capacitor divider to be identified and the key temperature of the second CVT capacitor divider needs to be calculated to generate relevant data on the temperature deviation of the key parts. This temperature deviation analysis will help identify possible abnormal conditions.

[0100] After the temperature deviation is calculated, further judgment is required. Pay special attention to whether the temperature deviation of key parts other than the outer surface of the fuel tank exceeds the preset abnormal overheating threshold, and confirm whether the temperature deviation of the outer surface of the fuel tank is within the safe range (that is, it does not exceed the preset abnormal overheating threshold). If it is found that the temperature deviation of key parts other than the outer surface of the fuel tank does exceed the set threshold, and the temperature deviation of the outer surface of the fuel tank remains within the safe range, it can be determined that the CVT to be identified for defects has the risk of local overheating abnormalities; if the above conditions are not met, it can be considered that the CVT to be identified for defects does not have local overheating abnormalities.

[0101] The abnormal overheating threshold may be 1°C.

[0102] Step S6: If the CVT to be identified has local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality, it is determined that the CVT to be identified has a capacitor voltage divider defect; otherwise, it is determined that the CVT to be identified has no capacitor voltage divider defect.

[0103] Furthermore, in a preferred embodiment, if the local temperature rise area of ​​the capacitor voltage divider is at the top of the porcelain sleeve rather than the middle, it indicates that there may be a capacitor defect caused by oil leakage. The acquisition device sends an alarm signal to remind the operating personnel to pay attention and deal with it in time according to the degree of the defect.

[0104] Based on the above method embodiment, the present invention provides a corresponding device embodiment.

[0105] like Figure 2 As shown, an embodiment of the present invention provides a CVT capacitor voltage divider defect identification device, including: a defect diagnosis data acquisition module, a voltage mutation judgment module, an external harmonic interference judgment module, an amplitude abnormality and phase abnormality judgment module, a local overheating abnormality judgment module and a capacitor voltage divider defect judgment module.

[0106] The defect diagnosis data acquisition module is used to acquire the secondary voltage waveform signal of the CVT to be identified, the infrared temperature measurement data of the CVT to be identified, the secondary voltage waveform signal of the first CVT and the infrared temperature measurement data of the second CVT; wherein the first CVT is a CVT connected to the same substation as the CVT to be identified and has no defects; the second CVT is the first CVT that is not connected to the same bus as the CVT to be identified but is in the same phase as the CVT;

[0107] The voltage mutation determination module is used to determine whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold and a secondary voltage waveform signal of the CVT to be identified;

[0108] The external harmonic interference determination module is used to determine whether the CVT to be identified has external harmonic interference according to a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified;

[0109] The amplitude abnormality and phase abnormality judgment module is used to judge whether the CVT to be identified by defects has amplitude abnormality and phase abnormality according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified by defects, and a secondary voltage waveform signal of the first CVT;

[0110] The local overheating abnormality determination module is used to determine whether the CVT to be identified has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified and the infrared temperature measurement data of the second CVT;

[0111] The capacitor voltage divider defect judgment module is used to determine that the CVT to be identified has a capacitor voltage divider defect when the CVT to be identified has a local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality; otherwise, it is determined that the CVT to be identified does not have a capacitor voltage divider defect.

[0112] It should be noted that the embodiment of the device described above corresponds to the above-mentioned embodiment of the present invention, and it can implement any one of the CVT capacitor voltage divider defect identification methods described above in the present invention. In addition, the embodiment of the above-mentioned device is merely schematic, wherein the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, in the accompanying drawings of the embodiment of the device provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which can be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement it without paying any creative labor.

[0113] Based on the above method embodiment of the present invention, a corresponding electronic device embodiment is provided.

[0114] An embodiment of the present invention provides an electronic device, comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the CVT capacitor voltage divider defect identification method described in any one of the present invention is implemented, or when the processor executes the computer program, the functions of each module in the above-mentioned device embodiments are implemented.

[0115] Exemplarily, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program in the terminal device.

[0116] The terminal device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0117] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the terminal device, and uses various interfaces and lines to connect various parts of the entire terminal device.

[0118] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the terminal device by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function, etc.; the data storage area can store data created according to the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0119] Based on the above method embodiment, the present invention provides a storage medium embodiment;

[0120] Another embodiment of the present invention provides a storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute any one of the above-mentioned CVT capacitor voltage divider defect identification methods of the present invention.

[0121] The storage medium is a computer-readable storage medium, and the computer program includes computer program code, which may be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0122] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0123] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for identifying defects in a CVT capacitor divider, characterized in that: include: Acquire the secondary voltage waveform signal of the CVT to be identified by defects, the infrared temperature measurement data of the CVT to be identified by defects, the secondary voltage waveform signal of the first CVT, and the infrared temperature measurement data of the second CVT; wherein the first CVT is a CVT that is connected to the same substation as the CVT to be identified by defects and has no defects; the second CVT is the first CVT that is not connected to the same bus as the CVT to be identified by defects but is in the same phase as the CVT; Determine whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold, and a secondary voltage waveform signal of the CVT to be identified; According to the preset harmonic content threshold and the secondary voltage waveform signal of the CVT to be identified, it is determined whether there is external harmonic interference in the CVT to be identified; According to the preset fundamental frequency voltage amplitude threshold, the preset fundamental frequency phase threshold, the secondary voltage waveform signal of the CVT to be identified by defects, and the secondary voltage waveform signal of the first CVT, it is determined whether the CVT to be identified by defects has amplitude abnormality and phase abnormality; According to the preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified as defective, and the infrared temperature measurement data of the second CVT, it is determined whether the CVT to be identified as defective has a local overheating abnormality; If the CVT to be identified has local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality, it is determined that the CVT to be identified has a capacitor voltage divider defect; otherwise, it is determined that the CVT to be identified has no capacitor voltage divider defect.

2. The CVT capacitor voltage divider defect identification method according to claim 1, characterized in that: The determining whether there is a voltage mutation in the CVT to be identified based on a preset time window, a preset voltage mutation threshold, and a secondary voltage waveform signal of the CVT to be identified includes: According to the preset time window, determine whether the voltage amplitude change of the secondary voltage waveform signal of the CVT to be identified within any time window exceeds the preset voltage mutation threshold. If so, it is determined that the CVT to be identified has a voltage mutation; if not, it is determined that the CVT to be identified has no voltage mutation.

3. The CVT capacitor voltage divider defect identification method according to claim 2, characterized in that: The method of judging whether the CVT to be identified as defective has external harmonic interference according to a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified as defective includes: Perform Fourier transformation on the secondary voltage waveform signal of the CVT to be identified, and obtain the first spectrum information after Fourier transformation; Extracting and generating the amplitude of each frequency component from the first spectrum information; Calculate and generate the harmonic content of the CVT to be defect-identified according to the amplitude of each frequency component; Determine whether the harmonic content of the CVT to be identified as defective exceeds a preset harmonic content threshold. If so, determine that the CVT to be identified as defective has external harmonic interference. If not, determine that the CVT to be identified as defective does not have external harmonic interference.

4. The CVT capacitor voltage divider defect identification method according to claim 3, characterized in that: The harmonic content of the CVT to be identified is calculated by the following formula: Wherein, THD is the harmonic content of the CVT to be identified; V1 is the amplitude of the fundamental frequency component; V i (i≠1) is the amplitude of the harmonic component numbered i; n is the sequence number of the harmonic component.

5. The CVT capacitor voltage divider defect identification method according to claim 4, characterized in that: The method of judging whether the CVT to be identified as defective has an abnormal amplitude and an abnormal phase according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified as defective, and a secondary voltage waveform signal of the first CVT includes: Extracting and generating the fundamental frequency voltage amplitude and the fundamental frequency phase of the CVT to be identified by the defect from the first frequency spectrum information; performing Fourier transformation on the secondary voltage waveform signal of the first CVT to obtain the second frequency spectrum information after Fourier transformation; Extracting the fundamental frequency voltage amplitude and the fundamental frequency phase of the first CVT from the second frequency spectrum information; Calculating the amplitude deviation between the fundamental frequency voltage amplitude of the CVT to be identified and the fundamental frequency voltage amplitude of the first CVT to generate a fundamental frequency voltage amplitude deviation; Calculate the phase deviation between the fundamental frequency phase of the CVT to be identified and the fundamental frequency phase of the first CVT to generate a fundamental frequency phase deviation; Determine whether the fundamental frequency voltage amplitude deviation exceeds a preset fundamental frequency voltage amplitude threshold value, if so, determine that the CVT to be identified for defects has an amplitude abnormality, if not, determine that the CVT to be identified for defects does not have an amplitude abnormality; Determine whether the fundamental frequency phase deviation exceeds a preset fundamental frequency phase threshold. If so, determine that the CVT to be identified for defects has a phase abnormality. If not, determine that the CVT to be identified for defects does not have a phase abnormality.

6. The CVT capacitor voltage divider defect identification method according to claim 5, characterized in that: The fundamental frequency voltage amplitude deviation is calculated by the following formula: Where ΔV is the fundamental frequency voltage amplitude deviation; V target V is the fundamental frequency voltage amplitude of the defect recognition CVT; temp is the fundamental frequency voltage amplitude of the first CVT; The fundamental frequency phase deviation is calculated by the following formula: Δφ=|φ target -f temp | Among them, Δφ is the fundamental frequency phase deviation; φ target is the fundamental frequency phase of the CVT to be identified; φ temp is the fundamental frequency phase of the first CVT.

7. The CVT capacitor voltage divider defect identification method according to claim 6, characterized in that: The method of judging whether the CVT to be identified as defective has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified as defective, and the infrared temperature measurement data of the second CVT includes: Extract the temperature of the key parts of the capacitor voltage divider of the CVT to be identified based on the infrared temperature measurement data of the CVT to be identified; extract the temperature of the key parts of the capacitor voltage divider of the second CVT based on the infrared temperature measurement data of the second CVT; wherein the key parts include the outer surface of the oil tank; Calculating the temperature difference between the key part temperature of the CVT capacitor voltage divider to be defect-identified and the key part temperature of the second CVT capacitor voltage divider to generate a key part temperature deviation; Determine whether the temperature deviation of key parts other than the outer surface of the fuel tank exceeds the preset abnormal overheating threshold and whether the temperature deviation of the outer surface of the fuel tank does not exceed the preset abnormal overheating threshold. If so, it is determined that the CVT to be identified as defective has local overheating abnormality; if not, it is determined that the CVT to be identified as defective does not have local overheating abnormality.

8. A CVT capacitor voltage divider defect identification device, characterized in that: include: Defect diagnosis data acquisition module, voltage mutation determination module, external harmonic interference determination module, amplitude anomaly and phase anomaly determination module, local overheating anomaly determination module and capacitor voltage divider defect determination module; The defect diagnosis data acquisition module is used to acquire the secondary voltage waveform signal of the CVT to be identified, the infrared temperature measurement data of the CVT to be identified, the secondary voltage waveform signal of the first CVT and the infrared temperature measurement data of the second CVT; wherein the first CVT is a CVT connected to the same substation as the CVT to be identified and has no defects; the second CVT is the first CVT that is not connected to the same bus as the CVT to be identified but is in the same phase as the CVT; The voltage mutation determination module is used to determine whether there is a voltage mutation in the CVT to be identified according to a preset time window, a preset voltage mutation threshold and a secondary voltage waveform signal of the CVT to be identified; The external harmonic interference determination module is used to determine whether the CVT to be identified has external harmonic interference according to a preset harmonic content threshold and a secondary voltage waveform signal of the CVT to be identified; The amplitude abnormality and phase abnormality judgment module is used to judge whether the CVT to be identified by defects has amplitude abnormality and phase abnormality according to a preset fundamental frequency voltage amplitude threshold, a preset fundamental frequency phase threshold, a secondary voltage waveform signal of the CVT to be identified by defects, and a secondary voltage waveform signal of the first CVT; The local overheating abnormality determination module is used to determine whether the CVT to be identified has a local overheating abnormality according to a preset abnormal overheating threshold, the infrared temperature measurement data of the CVT to be identified and the infrared temperature measurement data of the second CVT; The capacitor voltage divider defect judgment module is used to determine that the CVT to be identified has a capacitor voltage divider defect when the CVT to be identified has a local overheating abnormality, no voltage mutation, no external harmonic interference, no amplitude abnormality and no phase abnormality; otherwise, it is determined that the CVT to be identified does not have a capacitor voltage divider defect.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the CVT capacitor voltage divider defect identification method according to any one of claims 1 to 7 can be implemented.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it can implement the CVT capacitor voltage divider defect identification method described in any one of claims 1 to 7.

Images