Dry-type transformer turn-to-turn insulation fault detection method and system

Abstract

The invention discloses a turn-to-turn insulation fault detection method and system for a dry-type transformer, and relates to the field of power operation equipment detection. The method comprises the following steps: sampling signal data in real time through a signal acquisition and control unit and carrying out anti-interference processing; when a pulse impact test condition is met, the pulse control unit releases a high-voltage pulse signal; establishing a transformer winding equivalent circuit model according to the high-voltage pulse signal, and recording a pulse oscillation waveform; and waveform analysis and internal insulation state diagnosis are carried out through the equivalent circuit model. By adopting the high-voltage pulse technology, the accuracy and efficiency of turn-to-turn insulation fault detection of the dry-type transformer can be effectively improved; by establishing a transformer winding equivalent circuit model, the internal insulation state of the transformer can be monitored in real time, and potential fault hidden dangers can be found in advance; due to the introduction of the anti-interference processing circuit, the accuracy of signal acquisition is effectively improved, and the reliability of a detection result is ensured; the detection process is high in automation degree, the requirement for manual intervention is reduced, and the detection efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of electric power operation equipment detection, and in particular relates to a dry-type transformer turn-to-turn insulation fault detection method and system. Background Art

[0002] Dry-type transformers are widely used in power systems, and their safe and reliable operation is of great significance to ensuring the stability of power systems. Turn-to-turn insulation failure is one of the common faults of dry-type transformers. If it is not discovered and handled in time, it may cause equipment damage or even cause accidents. Therefore, it is of great practical significance to study an effective method for detecting turn-to-turn insulation failures in dry-type transformers.

[0003] The current methods for diagnosing inter-turn insulation are as follows: 1. DC resistance method. By testing the three-phase winding resistance and comparing the three-phase data deviation, it is possible to check whether the winding has a short circuit or poor contact. However, this method has complex wiring, a long test time, and is not sensitive to minor inter-turn short circuits; 2. Short-circuit impedance method. The short-circuit impedance method measures the output response voltage and current values ​​under the industrial frequency input voltage, and calculates the circuit equivalent impedance to determine the winding fault. This method has the disadvantages of poor detection sensitivity and a long test cycle; 3. Vibration analysis method. The vibration analysis method monitors the vibration signal of the winding when the transformer is running by installing professional sensors. When a winding fails, the characteristic quantities of the vibration signal, such as the spectrum and energy spectrum, will also change, thereby reflecting the operating status. The disadvantage of this method is the lack of a unified evaluation standard. At the same time, the technology is not yet mature, which affects the safety of the equipment. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed. The present invention uses the electrical pulse response characteristics to diagnose the insulation state inside the winding. A fast electrical pulse is applied to the winding of the transformer. When the pulse propagates in the winding, it will be affected by the internal resistance, inductance and capacitance of the winding. The winding in a normal state will produce a specific response to the electrical pulse, and any degradation or damage to the insulation between turns will cause this response to change. By accurately measuring these responses, faults in the transformer winding can be effectively detected.

[0005] Detailed analysis of the pulse response waveform, including measuring the pulse amplitude, propagation time, decay rate, and other characteristics of the waveform. The propagation time of the pulse can be used to locate the specific location of the fault, while the decay rate of the pulse can provide information about the insulation quality. In addition, the decay rate is also an important indicator for diagnosing internal problems in the winding.

[0006] On-site anti-interference processing uses advanced digital signal processing technologies. These technologies include waveform analysis, Fourier transform, digital filtering and other data processing algorithms. These algorithms can identify and analyze tiny waveform changes, even if these changes may not be very obvious in the original signal.

[0007] In order to solve the above technical problems, a dry-type transformer interturn insulation fault detection method is proposed, including: The signal acquisition and control unit samples the signal data in real time and performs anti-interference processing. When the pulse impact test conditions are met, the pulse control unit releases a high-voltage pulse signal. According to the high-voltage pulse signal, an equivalent circuit model of the transformer winding is established and the pulse oscillation waveform is recorded. The equivalent circuit model is used to perform waveform analysis and internal insulation status diagnosis.

[0008] As a preferred solution of the dry-type transformer inter-turn insulation fault detection method described in the present invention, the real-time sampling signal data includes source parameters and measurement parameters.

[0009] The source parameters include voltage output range, high voltage accuracy, and voltage step accuracy.

[0010] The measurement parameters include waveform sampling rate, inductance test range, test repeatability, test error range, and storage depth.

[0011] The anti-interference processing includes processing of external high and low frequency pulse electromagnetic noise by an EMC electromagnetic compatibility processing circuit composed of a filter network circuit composed of inductors and capacitors.

[0012] As a preferred solution of the dry-type transformer inter-turn insulation fault detection method described in the present invention, the pulse impact test condition includes real-time sampling of the feedback voltage by the signal acquisition and control unit to control the main voltage regulator T1, adjusting the output voltage to the set output voltage, and preparing the high voltage for the next pulse impact through the high-voltage rectifier and filter component composed of the current limiting module R1, the rectifier module D1, and the filter capacitor group C1, and adjusting the set output voltage to meet the following three conditions: Condition 1: Voltage output range of the test equipment The following conditions are met: , in, is the rated voltage of the dry-type transformer, is the safety margin, ; Condition 2: High voltage accuracy achieve Within ±5% of Condition 3: Voltage step accuracy achieve ±1%; When the source parameters meet the above three conditions at the same time, the possibility of the pulse control unit releasing a high-voltage pulse signal is determined: , in, In order to release the possibility of high voltage pulse signal, is the radius of the transformer, is the standard deviation of the voltage output, is the ideal voltage output value, is the minimum value of the voltage output range of the test equipment, is the maximum value of the voltage output range of the test equipment, is the initial radius of the transformer, is the minimum value of high pressure accuracy, is the influence function of the source parameter: , P=0 means that the high-voltage pulse signal is not allowed to be released, and P=1 means that the high-voltage pulse signal is allowed to be released; in, is the scaling factor of the source parameter, controlling the speed of exponential decay; is the threshold value of the source parameter, used to compare the integration results; It increases the nonlinearity of the function.

[0013] As a preferred embodiment of the dry-type transformer inter-turn insulation fault detection method described in the present invention, the establishment of the transformer winding equivalent circuit model includes applying a short high-voltage pulse to the transformer winding and observing the response. When the transformer operates normally, the internal structure of the transformer is determined and the parameters of the equivalent circuit are fixed. When the transformer winding has a short circuit or an open circuit inter-turn fault, the internal structure of the transformer changes, resulting in changes in the distributed parameters of the equivalent circuit and changes in the output characteristics.

[0014] When the transformer input excitation signal frequency is ≤1kHz, the influence of the distributed capacitance in the transformer model can be ignored. According to Kirchhoff's law, the low-frequency T-type equivalent circuit model of the transformer is: ; Transform the above formula to get: ; Since the excitation signal frequency is low, the transformer primary winding resistance and leakage inductance are small. When they are ignored, the low-frequency equivalent circuit is: ; in, , is the resistance and leakage inductance of the transformer primary winding, and are the voltage and current values ​​of the primary winding, are the voltage and current values ​​of the secondary winding, is the instantaneous magnetizing inductance, is the short-circuit leakage inductance.

[0015] When the excitation signal at the input end is between 10kHz and 50kHz, it is a high-frequency excitation parameter. When time t<0, the main capacitor is charged, and when time t≥0, the capacitor loop begins to discharge, which can be expressed using the second-order differential equation: ; With voltage u c Solve the equation as the unknown quantity and obtain the characteristic root p: ; u c The result is: ; ; ; in, is the input voltage of the RLC circuit, , is the characteristic root, , is the coefficient, C is the main capacitance, L is the equivalent inductance of the transformer winding coil, and R is the equivalent resistance on the winding coil; When an insulation fault occurs in the transformer, the electrical parameters change, the corresponding RLC value changes, and the time domain characteristics of the output voltage change; when When , the circuit is in an underdamped discharge state, and the solution is The expression is: ; in, is the phase angle, which describes the position of the sine wave on the time axis when it starts; the oscillation frequency and attenuation factor Respectively expressed as: ; The energy conversion in the current circuit will form periodic voltage changes. When an insulation failure occurs in the transformer, the equivalent resistance, equivalent reactance and equivalent impedance of the winding coil will change, causing changes in the oscillation frequency and attenuation factor. The insulation fault can be diagnosed by analyzing the changes in the waveform by comparing it with the normal waveform.

[0016] As a preferred solution of the dry-type transformer inter-turn insulation fault detection method described in the present invention, the waveform analysis includes recording the normal waveform state according to the historical operation data, and recording the pulse oscillation waveform according to the transformer winding equivalent circuit model. The waveform analysis result is expressed as: , in, It represents the comprehensive analysis result after comprehensively considering the characteristic parameters of pulse amplitude, propagation time, oscillation frequency and attenuation rate. Represents the time when pulse recording starts. represents the total propagation time of the pulse, represents the initial amplitude of the pulse, Represents the pulse oscillation waveform attenuation coefficient, represents the initial oscillation frequency of the pulse, represents the total number of characteristic parameters considered, t represents the time variable, represents the time delay parameter of the kth characteristic parameter, represents the attenuation coefficient of the kth characteristic parameter, Represents the weight of the kth feature parameter; When the value of F(t) is When , it means that no inter-turn insulation fault is detected. When , it indicates that there is an inter-turn insulation fault. When it is detected that the inter-turn insulation fault is not inter-turn and there is a transformer hardware fault, maintenance is required immediately; when The detection result is the difference between the normal waveform state and the pulse oscillation waveform when there is an inter-turn insulation fault, and the time period of the different points is recorded to determine the specific location of the fault and calculate the fault situation of the current fault time. : , The larger the value, the more serious the expression failure. and It is the time point when the normal waveform state and the pulse oscillation waveform differ from each other. is the rate at which the waveform decays, is the initial phase of the waveform; Calculate the decay rate: , Calculate the pulse amplitude change: , in, is the pulse amplitude variation during the fault time, is the pulse propagation time function, Describes the change of a pulse over time.

[0017] As a preferred solution of the dry-type transformer interturn insulation fault detection method described in the present invention, the internal insulation state diagnosis includes: When the value is between 0 and the set threshold value f1, it indicates that the internal insulation state of the transformer is in a slight fault state. There is a problem but it will not affect the operation. Arrange a preventive maintenance plan and keep monitoring. Combining decay rate and pulse amplitude changes for fault prediction: , when =1, it means that the internal insulation state will become serious, and the internal insulation state will be classified as a serious fault state for transformer maintenance. =0, indicating that the internal insulation condition is not becoming serious and monitoring continues. Represents the severity trend of the fault point, and are the contribution weights of pulse amplitude change and attenuation rate to fault prediction, Adjusting the contribution of the decay rate ensures that the function values ​​are within a comparable range; when When the value is between the set thresholds f1 and f2, it indicates that the internal insulation state of the transformer is in a serious fault state. Data analysis is performed and the problem is investigated and solved through the fault emergency plan. when When the value is greater than the set threshold value f2, it indicates that the internal insulation state of the transformer is in a critical fault state. The transformer will shut down within 5 minutes, causing losses. The transformer should be isolated from other equipment and replaced urgently. At the same time, the standby transformer should be activated to reduce the impact on normal operation. Among them, f1 and f2 are the thresholds for judging the internal insulation status, expressed as: , , in, is the average value of the transformer data under normal operation, is the standard deviation of the transformer data for normal operation, is the average value of the data of the faulty transformer, is the standard deviation of the data for the faulty transformer, and It is a constant determined based on risk tolerance and false alarm rate.

[0018] As a preferred solution of the dry-type transformer inter-turn insulation fault detection method described in the present invention, the internal insulation state diagnosis also includes that the internal insulation state of the transformer is in a serious fault state, data analysis is performed, the winding insulation change is simulated by series inductance and parallel capacitance, the degree of fault is simulated by changing the capacitance and inductance values, and the parameter change trend is analyzed, including the percentage change of the impulse waveform period, the impulse waveform area, the impulse waveform area difference, and the impulse waveform phase difference, and the transformer performance indicators are comprehensively evaluated according to the percentage value: , The larger the value, the less damage the transformer will suffer in a severe fault condition. The smaller it is, the greater the damage to the transformer is under severe fault conditions; in, It is the main function used to comprehensively evaluate the performance indicators of transformers. is the number of all parameters, It simulates the change of winding insulation. is the parallel capacitor, is the series inductor, It is the actual measured value of the impulse waveform period, area, area difference and phase difference. and are the mean and variance of the impulse waveform period, area, area difference and phase difference, respectively. represents the percentage change of the impact waveform period, area, area difference and phase difference, x represents the impact waveform period, impact waveform area, impact waveform area difference and impact waveform phase difference, Represents the overall performance of turn-to-turn insulation.

[0019] Another object of the present invention is to provide a dry-type transformer inter-turn insulation fault detection system, which is designed to ensure the safe and stable operation of dry-type transformers in power systems and prevent equipment damage and power accidents caused by inter-turn insulation faults. The system collects the electrical parameters of the transformer in real time through the hardware processing module, and uses the software processing module to analyze the data to identify potential problems with inter-turn insulation. The human-computer interaction module provides a friendly operating interface and a timely alarm system, allowing operators to quickly respond to and handle detected faults.

[0020] Through the close cooperation of these three modules, the system solves the problem of difficulty in early detection and diagnosis of inter-turn insulation faults in dry-type transformers, improves the accuracy and efficiency of fault detection, and reduces economic losses and maintenance costs caused by faults. In addition, the system's remote monitoring function makes maintenance more convenient, greatly improving the level of intelligent management of the power system, and achieving the effect of ensuring power supply reliability, extending equipment service life, and improving system safety.

[0021] As a preferred solution of the dry-type transformer interturn insulation fault detection system described in the present invention, it is characterized by comprising a hardware processing module, a software processing module and a human-computer interaction module.

[0022] The hardware processing module includes a main control unit, a power supply and noise processing unit, a boost, rectification and voltage measurement unit, a drive control and signal measurement unit, and a peripheral unit. The system is powered by a power circuit, the circuit composition output control function is performed by a core control and processing function, the waveform is measured by a signal acquisition and control function and a signal processing function, and the module also has a data storage and recording unit and a data output function for comparing and analyzing waveforms when used.

[0023] The software processing module includes a waveform status display unit and a software control and detection unit, which receives data transmitted from the hardware module, cooperates with the hardware to control output and waveform detection functions, and has interactive functions for data display and analysis.

[0024] The human-computer interaction module provides an operation interface, allowing the user to input instructions, view real-time data, diagnostic results and historical records on the LCD display, access the system through a remote terminal, and perform monitoring and control operations.

[0025] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of a method for detecting inter-turn insulation fault of a dry-type transformer are implemented.

[0026] A computer-readable storage medium stores a computer program thereon, wherein when the computer program is executed by a processor, the steps of a method for detecting inter-turn insulation fault of a dry-type transformer are implemented.

[0027] The beneficial effects of the present invention are as follows: the present invention utilizes the electrical pulse response characteristics to diagnose the insulation state inside the winding, and has the characteristics of fast testing speed and sensitive fault response. The pulse response waveform of the present invention is displayed in a graphical manner, which can intuitively reflect the type and degree of the fault, and is convenient for analysis and judgment. The present invention adopts advanced digital signal processing technology, which can enhance the anti-interference ability of on-site testing.

[0028] In addition, the present invention adopts high-voltage pulse technology, which can effectively improve the accuracy and efficiency of dry-type transformer inter-turn insulation fault detection; by establishing a transformer winding equivalent circuit model, it can monitor the internal insulation state of the transformer in real time and discover potential fault hazards in advance; the introduction of anti-interference processing circuit effectively improves the accuracy of signal acquisition and ensures the reliability of detection results; the detection process has a high degree of automation, reduces the need for manual intervention, and improves detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 An overall flow chart of a dry-type transformer interturn insulation fault detection method provided by an embodiment of the present invention.

[0030] Figure 2 A transformer equivalent circuit model under low-frequency excitation for a dry-type transformer interturn insulation fault detection method provided by an embodiment of the present invention.

[0031] Figure 3 A transformer distributed parameter model under medium and high frequency excitation for a dry-type transformer interturn insulation fault detection method provided in one embodiment of the present invention.

[0032] Figure 4 A system functional architecture diagram of a dry-type transformer interturn insulation fault detection system provided by an embodiment of the present invention.

[0033] Figure 5 A system solution design diagram of a dry-type transformer interturn insulation fault detection system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0037] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0038] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Example 1, reference Figure 1-Figure 3 , which is the first embodiment of the present invention, provides a method for detecting inter-turn insulation fault of a dry-type transformer, comprising: S1: The signal acquisition and control unit samples the signal data in real time and performs anti-interference processing.

[0041] Furthermore, the real-time sampling signal data includes source parameters and measurement parameters.

[0042] The source parameters include voltage output range, high voltage accuracy, and voltage step accuracy.

[0043] The measurement parameters include waveform sampling rate, inductance test range, test repeatability, test error range, and storage depth.

[0044] The anti-interference processing includes processing of external high and low frequency pulse electromagnetic noise by an EMC electromagnetic compatibility processing circuit composed of a filter network circuit composed of inductors and capacitors.

[0045] It should be noted that the use of advanced digital signal processing techniques including waveform analysis, Fourier transform, and digital filtering, these algorithms can identify and analyze tiny waveform changes, even if these changes may not be very obvious in the original signal.

[0046] S2: When the pulse shock test conditions are met, the pulse control unit releases a high-voltage pulse signal.

[0047] Furthermore, the signal acquisition and control unit samples the feedback voltage in real time to control the main voltage regulator T1, adjusts the output voltage to the set output voltage, and the high-voltage rectifier and filter component composed of the current limiting module R1, the rectifier module D1, and the filter capacitor group C1 prepares the high voltage for the next pulse impact. When the set output voltage meets the following three conditions: Condition 1: Voltage output range of the test equipment The following conditions are met: , in, is the rated voltage of the dry-type transformer, is the safety margin, ; Condition 2: High voltage accuracy achieve Within ±5% of Condition 3: Voltage step accuracy achieve ±1%; When the source parameters meet the above three conditions at the same time, the possibility of the pulse control unit releasing a high-voltage pulse signal is determined: , in, In order to release the possibility of high voltage pulse signal, is the radius of the transformer, is the standard deviation of the voltage output, is the ideal voltage output value, is the minimum value of the voltage output range of the test equipment, is the maximum value of the voltage output range of the test equipment, is the initial radius of the transformer, is the minimum value of high pressure accuracy, is the influence function of the source parameter: , P=0 means that the high-voltage pulse signal is not allowed to be released, and P=1 means that the high-voltage pulse signal is allowed to be released; in, is the scaling factor of the source parameter, controlling the speed of exponential decay; is the threshold value of the source parameter, used to compare the integration results; It increases the nonlinearity of the function.

[0048] S3: Establish a transformer winding equivalent circuit model based on the high-voltage pulse signal and record the pulse oscillation waveform.

[0049] Furthermore, if Figure 2 As shown, a short high-voltage pulse is applied to the transformer winding and the response is observed. When the transformer operates normally, the internal structure of the transformer is determined, so the parameters of the equivalent circuit are fixed. When the transformer winding is short-circuited or open-circuited, the internal structure of the transformer changes, causing the distributed parameters of the equivalent circuit to change, and the output characteristics will also change.

[0050] When the transformer input excitation signal frequency is ≤1kHz, the influence of the distributed capacitance in the transformer model can be ignored. According to Kirchhoff's law, the low-frequency T-type equivalent circuit model of the transformer is: ; Transform the above formula to get: ; Since the excitation signal frequency is low, the transformer primary winding resistance and leakage inductance are small. When they are ignored, the low-frequency equivalent circuit is: ; in, , is the resistance and leakage inductance of the transformer primary winding, and are the voltage and current values ​​of the primary winding, are the voltage and current values ​​of the secondary winding, is the instantaneous magnetizing inductance, is the short-circuit leakage inductance.

[0051] When the excitation signal at the input end is between 10kHz and 50kHz, it is a high-frequency excitation parameter. The magnetic permeability of the iron core in the transformer is the same as the magnetic permeability of the air, so it is ignored. At this time, the high-frequency equivalent circuit model is a circuit composed of RLC parameters. At this time, the equivalent distributed capacitance is ignored. When time t<0, the main capacitor is charged, and when time t≥0, the capacitor loop begins to discharge, which is expressed by the second-order differential equation: ; With voltage u c Solve the equation as the unknown quantity and obtain the characteristic root p: ; u c The result is: ; ; ; in, is the input voltage of the RLC circuit, , is the characteristic root, , is the coefficient, C is the main capacitance, L is the equivalent inductance of the transformer winding coil, and R is the equivalent resistance on the winding coil; When an insulation failure occurs in the transformer, the electrical parameters will change, the corresponding RLC value will change, and the time domain characteristics of the output voltage will also change; when When , the circuit is in an underdamped discharge state, and the solution is The expression is: ; in, is the phase angle, which describes the position of the sine wave on the time axis when it starts; the oscillation frequency and attenuation factor Respectively expressed as: ; At this time, the energy conversion in the circuit will form a periodic voltage change. When the transformer has an insulation failure, the equivalent resistance, equivalent reactance and equivalent impedance of the winding coil will change, causing the oscillation frequency and attenuation factor to change. The insulation fault can be diagnosed by comparing and analyzing the waveform changes with the normal waveform.

[0052] S4: Perform waveform analysis and internal insulation status diagnosis through equivalent circuit model.

[0053] Furthermore, according to the historical operation data, the normal waveform state is recorded, and according to the equivalent circuit model, the pulse oscillation waveform is recorded, and the waveform analysis result is expressed as: , in, It represents the comprehensive analysis result after comprehensively considering the characteristic parameters of pulse amplitude, propagation time, oscillation frequency and attenuation rate. Represents the time when pulse recording starts. represents the total propagation time of the pulse, represents the initial amplitude of the pulse, Represents the pulse oscillation waveform attenuation coefficient, represents the initial oscillation frequency of the pulse, represents the total number of characteristic parameters considered, t represents the time variable, represents the time delay parameter of the kth characteristic parameter, represents the attenuation coefficient of the kth characteristic parameter, Represents the weight of the kth feature parameter.

[0054] When the value of F(t) is When , it means that no inter-turn insulation fault is detected. When , it indicates that there is an inter-turn insulation fault. When , it indicates that the inter-turn detection is not an inter-turn insulation fault and there is a transformer hardware fault, and immediate maintenance is required.

[0055] when The detection result is the difference between the normal waveform state and the pulse oscillation waveform when there is an inter-turn insulation fault, and the time period of the different points is recorded to determine the specific location of the fault and calculate the fault situation of the current fault time. : The larger the value, the more serious the expression failure. and It is the time point when the normal waveform state and the pulse oscillation waveform differ from each other. is the rate at which the waveform decays, is the initial phase of the waveform.

[0056] Calculate the decay rate: ; Calculate the pulse amplitude change: ; in, is the pulse amplitude variation during the fault time, is the pulse propagation time function, Describes the change of a pulse over time.

[0057] It should be noted that when When the value is between 0 and f1, it indicates that the internal insulation state of the transformer is in a minor fault state. There is a problem but it will not affect the operation. Arrange a preventive maintenance plan and keep monitoring.

[0058] Combining decay rate and pulse amplitude changes for fault prediction: when =1, it means that the internal insulation state will become serious. At this time, the internal insulation state is classified as a serious fault state and the transformer is repaired. =0, indicating that the internal insulation condition is not becoming serious and monitoring continues. Represents the severity trend of the fault point, and are the contribution weights of pulse amplitude change and attenuation rate to fault prediction, Adjusting the contribution of the decay rate ensures that the function values ​​are within a comparable range.

[0059] when When the value is between f1 and f2, it indicates that the internal insulation state of the transformer is in a serious fault state. Data analysis is carried out and the problem is investigated and solved through the fault emergency plan.

[0060] when When the value is greater than f2, it indicates that the internal insulation state of the transformer is in a critical fault state. The transformer will shut down within 5 minutes, causing losses. The transformer should be isolated from other systems and replaced urgently. At the same time, the standby transformer should be activated to reduce the impact on normal operation.

[0061] Among them, f1 and f2 are the thresholds for judging the internal insulation status, expressed as: in, is the average value of the transformer data under normal operation, is the standard deviation of the transformer data for normal operation, is the average value of the data of the faulty transformer, is the standard deviation of the data for the faulty transformer, and is a constant determined by risk tolerance and false alarm rate. =2, .

[0062] It should also be noted that the Represents the percentage change of the impulse waveform period, the impulse waveform area, the impulse waveform area difference and the impulse waveform phase difference; in the impulse waveform period method, when the impulse voltage is applied to the transformer winding coil for testing, the winding inductance and the oscillation capacitor resonate, and the oscillation period of the generated attenuated oscillation wave can reflect the inductance information of the coil. By comparing the changes in the impulse wave period, the insulation condition of the winding coil can be reflected. When analyzing the data, the zero point of the oscillation waveform is used as the start and end of the period judgment, and multiple period waveforms can be sampled at the same time to reduce the sampling error. When sampling m periods, the sampling frequency is set to When the periodic wave starts , ending with , then the test waveform sampling period for: The standard period of the oscillation wave when the coil winding is normal is , calculate the test waveform period error percentage for: The impulse waveform area comparison method determines the inter-turn insulation fault by the area enclosed by the impulse response waveform and the time axis. When the transformer winding is in a normal state, the area between interval I and interval J is the standard area. When an inter-turn fault occurs, the equivalent electrical parameters R and L will change, the oscillation wave waveform will also change, and the area between interval I and interval J will also change. The difference between the two can be calculated to determine the change of parameters R and L and insulation faults such as inter-turn short circuits. The area calculation formula S is: The standard waveform area is S0, and the impact waveform area difference is percentage for: The impulse waveform area difference ratio method uses the area difference between the measured waveform and the standard waveform curve to judge the change in transformer winding inductance and inter-turn short circuit. The area difference ratio method can intuitively reflect the offset relationship between the two curves and can effectively judge the situation where the area change is not large but the area difference change is obvious. In the range of interval I to interval J, the standard waveform is , the measured winding waveform is , the area difference is calculated as: When analyzing data, the insulation condition of the winding is determined by the percentage of the area of ​​the measured waveform and the standard waveform: The impulse waveform phase difference method compares the phases of the specified zero-crossing points of the standard waveform and the waveform under test, taking the zero-crossing point of the standard waveform as the , the zero crossing point of the measured waveform is , the pulse waveform response period is , and the percentage is obtained by comparing the phase difference for: In the test, the insulation change of the winding is simulated by connecting inductors in series and capacitors in parallel, and the degree of fault is simulated by changing the capacitance and inductance values. By comparing the standard waveform in the normal state and the measured waveform in the fault state and statistically analyzing the parameters, the parameter change trend is further analyzed, including the percentage change of the impulse waveform period, impulse waveform area, impulse waveform area difference, and impulse waveform phase difference. Finally, the transformer performance indicators are comprehensively evaluated according to the percentage values: , The larger the value, the less damage the transformer will suffer in a severe fault condition. The smaller it is, the greater the damage to the transformer will be under severe fault conditions.

[0063] in, It is the main function used to comprehensively evaluate the performance indicators of transformers. is the number of all parameters, It simulates the change of winding insulation. is the parallel capacitor, is the series inductor, It is the actual measured value of the impulse waveform period, area, area difference and phase difference. and are the mean and variance of the impulse waveform period, area, area difference and phase difference, respectively. represents the percentage change of the impact waveform period, area, area difference and phase difference, x represents the impact waveform period, impact waveform area, impact waveform area difference and impact waveform phase difference, Represents the overall performance of turn-to-turn insulation.

[0064] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0065] Embodiment 2, an embodiment of the present invention, provides a method for detecting inter-turn insulation fault of a dry-type transformer. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through experiments.

[0066] The present invention selects three different dry-type transformers as test objects, which are marked as A, B, and C. A represents the traditional detection method, i.e., the direct measurement method; B represents an existing technology on the market, i.e., the digital insulation tester; and C represents the method proposed by the present invention. The three transformers are similar in terms of rated voltage, structure, service life, etc., to ensure the fairness of the test.

[0067] First, we use the signal acquisition and control unit to sample the three transformers in real time and record the source parameters and measurement parameters. The source parameters include voltage output range, high voltage accuracy, and voltage step accuracy, while the measurement parameters include waveform sampling rate, inductance test range, test repeatability, test error range, and storage depth. Then, through anti-interference processing, including EMC electromagnetic compatibility processing circuit, external high and low frequency pulse electromagnetic noise is processed.

[0068] After the pulse impact test conditions are met, we use the pulse control unit to release high-voltage pulse signals to the transformer windings, establish an equivalent circuit model of the transformer windings, and record the pulse oscillation waveform. Through the equivalent circuit model, we perform waveform analysis and internal insulation status diagnosis.

[0069] Tables 1 and 2 record the performance of three different transformers in various parameters: Table 1 transformer Voltage output range High pressure accuracy Voltage step accuracy Waveform sampling rate Inductance test range A 0.80-1.20 ±10% ±2.0% 50kHz 0-100H B 0.90-1.10 ±7% ±1.5% 100kHz 0-150H C 0.85-1.15 ±5% ±1.0% 200kHz 0-200H Table 2 transformer Test repeatability Test error range Storage Depth Anti-interference effect Fault detection accuracy A 90% ±5% 1024 generally 70% B 95% ±3% 2048 good 85% C 98% ±2% 4096 excellent 98% The dry-type transformer interturn insulation fault detection method C proposed by the present invention is significantly superior to the traditional detection method A and the existing technology B on the market in terms of various parameters.

[0070] The C transformer is closer to the rated voltage of the transformer, which helps to detect inter-turn insulation faults more accurately. In terms of high-voltage accuracy and voltage step accuracy, the C transformer has higher accuracy, which means it can control the high-voltage pulse signal more accurately, thereby improving the accuracy of fault detection.

[0071] The increase in waveform sampling rate and inductance test range enables the C transformer to capture more subtle signal changes, thereby more accurately diagnosing the insulation status. The improvement in test repeatability and test error range further ensures the reliability of the test results.

[0072] The improvement of the C transformer in the processing of high and low frequency pulse electromagnetic noise has significantly improved the quality of the detection signal, and the fault detection accuracy has been significantly improved from 70% to 98%. The invention has innovation and advantages in the detection of inter-turn insulation faults of dry-type transformers.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

[0074] Embodiment 3, the third embodiment of the present invention, is different from the first two embodiments in that: If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0075] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0076] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0077] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0078] Example 4, reference Figure 4-Figure 5 , which is the fourth embodiment of the present invention, provides a dry-type transformer inter-turn insulation fault detection system, including a hardware processing module, a software processing module and a human-computer interaction module.

[0079] The hardware processing module includes a main control unit, a power supply and noise processing unit, a boost, rectification and voltage measurement unit, a drive control and signal measurement unit, and a peripheral unit. The system is powered by a power circuit, the circuit composition output control function is performed by a core control and processing function, the waveform is measured by a signal acquisition and control function and a signal processing function, and the module also has a data storage and recording unit and a data output function for comparing and analyzing waveforms when used.

[0080] like Figure 5 As shown, the main control unit includes a complete machine control system with the control motherboard CPU as the core, which uses the external I / O port of the device as input and output control and the collection of analog signals of various sensors, circuit protection and system industrial control unit communication, built-in waveform acquisition card communication, output PWM pulse to drive the high-voltage main circuit module, control and adjust the output given voltage, and correct, read, analyze, compare, and judge the collected data.

[0081] Power supply and noise processing unit: The system is connected to an external 220V AC power supply, which is used by each functional unit after being processed by an EMC electromagnetic compatibility processing circuit composed of a filter network circuit composed of specific inductors and capacitors for external high and low frequency pulse electromagnetic noise, so as to ensure the purity of the power supply quality of each functional unit of the system and reduce the influence of line and external interference on the measurement. The input 220V power supply is supplied to the automatic adjustable voltage regulator T1 to output adjustable AC 0-200V for use in the subsequent main circuit, and the corresponding power supply system voltage stabilization module is used to provide working power to each system branch unit circuit.

[0082] The boost, rectifier and voltage measurement unit, including the boost transformer T2, the current limiting module R1, the rectifier module D1, and the filter capacitor group C1, form the main power rectifier and filter circuit, which boosts the AC 0-200V of the front stage to DC 0-20KV voltage, and provides the output voltage for the rear high-voltage main circuit. The voltage measurement unit monitors the loop voltage in real time for the main control unit drone display and provides protection control signals.

[0083] Drive control and signal measurement unit: including pulse drive unit. The pulse output control signal of this part of the circuit is triggered by the screen to control the Q1 high-speed high-voltage disconnection module to release high voltage to form high-voltage pulses in the T3 output circuit. The high-voltage controllable power main circuit, output circuit and protection circuit are composed of R2, Q1, R3 and C2. The signal data acquisition circuit obtains the signal output waveform through voltage division by R4 and R5 circuits, and performs signal conditioning through the conditioning circuit to improve the accuracy and meet the high-speed ADC sampling range. The sampled data is sent to the main control unit to complete the subsequent data display and analysis functions.

[0084] Peripheral unit: mainly composed of computer system, host control measurement and analysis software, cooperating with main control unit and various functional units to complete the control of the whole machine, data communication, data acquisition, data display, data analysis, data storage, information input and output, etc.

[0085] The software processing module includes a waveform status display unit and a software control and detection unit, which receives data transmitted from the hardware module, cooperates with the hardware to control output and waveform detection functions, and has interactive functions for data display and analysis.

[0086] The human-computer interaction module provides an operation interface, allowing the user to input instructions, view real-time data, diagnostic results and historical records on the LCD display, access the system through a remote terminal, and perform monitoring and control operations.

[0087] The whole machine control process is that the whole machine control is controlled by the computer host control system software to set the pulse output set voltage according to the user's actual test product working characteristics, and the voltage sampling and measurement unit samples the feedback voltage in real time to control the main voltage regulator T1, adjust the output voltage to the set output voltage, and prepare the high voltage for the next pulse impact through the high-voltage rectifier and filter components composed of R1, D1, and C1. After the pulse impact test conditions are met on site, the operator clicks the start test button, and the system issues an output instruction to the pulse control unit. The pulse control unit sends a pulse trigger to control the thyristor component to release high voltage to the test product. The high-voltage pulse signal released will form an oscillation in the RC series network composed of the test product and the main circuit R3 and C2. The oscillation process will be collected in real time by the pulse sampling unit composed of R4 and R5 and recorded and uploaded to the host computer software. After being processed by the software algorithm, a clear and readable oscillation waveform can be formed. The measured waveform can be compared with the same phase and same period and previous waveform data to form a defect development trend and fault diagnosis basis report of the test product.

[0088] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for detecting interturn insulation fault of a dry-type transformer, characterized in that: include, The signal acquisition and control unit samples the signal data in real time and performs anti-interference processing; When the pulse impact test conditions are met, the pulse control unit releases a high-voltage pulse signal; Establish the transformer winding equivalent circuit model according to the high-voltage pulse signal and record the pulse oscillation waveform; Perform waveform analysis and internal insulation status diagnosis using equivalent circuit models.

2. A dry-type transformer interturn insulation fault detection method as claimed in claim 1, characterized in that: The real-time sampling signal data includes source parameters and measurement parameters; The source parameters include voltage output range, high voltage accuracy, and voltage step accuracy; The measurement parameters include waveform sampling rate, inductance test range, test repeatability, test error range, and storage depth; The anti-interference processing includes processing of external high and low frequency pulse electromagnetic noise by an EMC electromagnetic compatibility processing circuit composed of a filter network circuit composed of inductors and capacitors.

3. A dry-type transformer interturn insulation fault detection method as claimed in claim 2, characterized in that: The pulse impact test condition includes real-time sampling of the feedback voltage by the signal acquisition and control unit to control the main voltage regulator T1, adjust the output voltage to the set output voltage, and prepare the high voltage for the next pulse impact through the high-voltage rectifier and filter component composed of the current limiting module R1, the rectifier module D1, and the filter capacitor group C1. When the set output voltage meets the following three conditions: Condition 1: Voltage output range of the test equipment The following conditions are met: ， in, is the rated voltage of the dry-type transformer, is the safety margin, ; Condition 2: High voltage accuracy achieve Within ±5% of Condition 3: Voltage step accuracy achieve ±1%; When the source parameters meet the above three conditions at the same time, the possibility of the pulse control unit releasing a high-voltage pulse signal is determined: ， in, In order to release the possibility of high voltage pulse signal, is the radius of the transformer, is the standard deviation of the voltage output, is the ideal voltage output value, is the minimum value of the voltage output range of the test equipment, is the maximum value of the voltage output range of the test equipment, is the initial radius of the transformer, is the minimum value of high pressure accuracy, is the influence function of the source parameter: ， P=0 means that the high-voltage pulse signal is not allowed to be released, and P=1 means that the high-voltage pulse signal is allowed to be released; in, is the scaling factor of the source parameter, controlling the speed of exponential decay; is the threshold value of the source parameter, used to compare the integration results; It increases the nonlinearity of the function.

4. A dry-type transformer interturn insulation fault detection method as claimed in claim 3, characterized in that: The establishment of the transformer winding equivalent circuit model includes applying a short high-voltage pulse to the transformer winding and observing the response. When the transformer operates normally, the internal structure of the transformer is determined and the parameters of the equivalent circuit are fixed. When the transformer winding is short-circuited or an open-circuited winding turn fault occurs, the internal structure of the transformer changes, resulting in changes in the distributed parameters of the equivalent circuit and changes in the output characteristics. When the transformer input excitation signal frequency is ≤1kHz, the influence of the distributed capacitance in the transformer model can be ignored. According to Kirchhoff's law, the low-frequency T-type equivalent circuit model of the transformer is: ， Transform the above formula to get: ， Since the excitation signal frequency is low, the transformer primary winding resistance and leakage inductance are small. When they are ignored, the low-frequency equivalent circuit is: ， in, , is the resistance and leakage inductance of the transformer primary winding, and are the voltage and current values ​​of the primary winding, are the voltage and current values ​​of the secondary winding, is the instantaneous magnetizing inductance, is the short-circuit leakage inductance; When the excitation signal at the input end is between 10kHz and 50kHz, it is a high-frequency excitation parameter. When time t<0, the main capacitor is charged, and when time t≥0, the capacitor loop begins to discharge, which can be expressed using the second-order differential equation: ， With voltage u c Solve the equation as the unknown quantity and obtain the characteristic root p: ， u c The result is: ， ， ， in, is the input voltage of the RLC circuit, , is the characteristic root, , is the coefficient, C is the main capacitance, L is the equivalent inductance of the transformer winding coil, and R is the equivalent resistance on the winding coil; When an insulation fault occurs in the transformer, the electrical parameters change, the corresponding RLC value changes, and the time domain characteristics of the output voltage change; when When the circuit is in an underdamped discharge state, we can get The expression is: ， in, is the phase angle, which describes the position of the sine wave on the time axis when it starts; the oscillation frequency and attenuation factor Respectively expressed as: ， The energy conversion in the current circuit will form periodic voltage changes. When an insulation failure occurs in the transformer, the equivalent resistance, equivalent reactance and equivalent impedance of the winding coil will change, causing changes in the oscillation frequency and attenuation factor. The insulation fault can be diagnosed by analyzing the changes in the waveform by comparing it with the normal waveform.

5. A dry-type transformer interturn insulation fault detection method as claimed in claim 4, characterized in that: The waveform analysis includes recording the normal waveform state according to the historical operation data, and recording the pulse oscillation waveform according to the transformer winding equivalent circuit model. The waveform analysis result is expressed as: ， in, It represents the comprehensive analysis result after comprehensively considering the characteristic parameters of pulse amplitude, propagation time, oscillation frequency and attenuation rate. Represents the time when pulse recording starts. represents the total propagation time of the pulse, represents the initial amplitude of the pulse, Represents the pulse oscillation waveform attenuation coefficient, represents the initial oscillation frequency of the pulse, represents the total number of characteristic parameters considered, t represents the time variable, represents the time delay parameter of the kth characteristic parameter, represents the attenuation coefficient of the kth characteristic parameter, Represents the weight of the kth feature parameter; When the value of F(t) is When , it means that no inter-turn insulation fault is detected. When , it indicates that there is an inter-turn insulation fault. When it is detected that the inter-turn insulation fault is not inter-turn and there is a transformer hardware fault, maintenance is required immediately; when The detection result is the difference between the normal waveform state and the pulse oscillation waveform when there is an inter-turn insulation fault, and the time period of the different points is recorded to determine the specific location of the fault and calculate the fault situation of the current fault time. : ， The larger the value, the more serious the expression failure. and It is the time point when the normal waveform state and the pulse oscillation waveform differ from each other. is the rate at which the waveform decays, is the initial phase of the waveform; Calculate the decay rate: ， Calculate the pulse amplitude change: ， in, is the pulse amplitude variation during the fault time, is the pulse propagation time function, Describes the change of a pulse over time.

6. A dry-type transformer interturn insulation fault detection method as claimed in claim 5, characterized in that: The internal insulation status diagnosis includes When the value is between 0 and the set threshold value f1, it indicates that the internal insulation state of the transformer is in a slight fault state. There is a problem but it will not affect the operation. Arrange a preventive maintenance plan and keep monitoring. Fault prediction based on decay rate and pulse amplitude changes: ， when =1, it means that the internal insulation state will become serious, and the internal insulation state will be classified as a serious fault state for transformer maintenance. =0, indicating that the internal insulation condition is not becoming serious and monitoring continues. Represents the severity trend of the fault point, and are the contribution weights of pulse amplitude change and attenuation rate to fault prediction, Adjusting the contribution of the decay rate ensures that the function values ​​are within a comparable range; when When the value is between the set thresholds f1 and f2, it indicates that the internal insulation state of the transformer is in a serious fault state. Data analysis is performed and the problem is investigated and solved through the fault emergency plan. when When the value is greater than the set threshold value f2, it indicates that the internal insulation state of the transformer is in a critical fault state. The transformer will shut down within 5 minutes, causing losses. The transformer should be isolated from other equipment and replaced urgently. At the same time, the standby transformer should be activated to reduce the impact on normal operation. Among them, f1 and f2 are the thresholds for judging the internal insulation status, expressed as: ， ， in, is the average value of the transformer data under normal operation, is the standard deviation of the transformer data for normal operation, is the average value of the data of the faulty transformer, is the standard deviation of the data for the faulty transformer, and It is a constant determined based on risk tolerance and false alarm rate.

7. A dry-type transformer interturn insulation fault detection method as claimed in claim 6, characterized in that: The internal insulation status diagnosis also includes the transformer internal insulation status being in a serious fault state, performing data analysis, simulating the winding insulation change by connecting inductors in series and capacitors in parallel, simulating the degree of the fault by changing the capacitance and inductance values, analyzing the parameter change trend, including the percentage change of the impulse waveform period, the impulse waveform area, the impulse waveform area difference, and the impulse waveform phase difference, and comprehensively evaluating the transformer performance indicators according to the percentage values: ， The larger it is, the less damage the transformer will suffer in a severe fault condition. The smaller it is, the greater the damage to the transformer is under severe fault conditions; in, It is the main function used to comprehensively evaluate the performance indicators of transformers. is the number of all parameters, It simulates the change of winding insulation. is the parallel capacitor, is the series inductor, It is the actual measured value of the impulse waveform period, area, area difference and phase difference. and are the mean and variance of the impulse waveform period, area, area difference and phase difference, respectively. represents the percentage change of the impact waveform period, area, area difference and phase difference, x represents the impact waveform period, impact waveform area, impact waveform area difference and impact waveform phase difference, Represents the overall performance of turn-to-turn insulation.

8. A system using a dry-type transformer turn-to-turn insulation fault detection method as claimed in any one of claims 1 to 7, characterized in that: Including hardware processing module, software processing module and human-computer interaction module; The hardware processing module includes a main control unit, a power supply and noise processing unit, a boost, a rectification and voltage measurement unit, a drive control and signal measurement unit, and a peripheral unit. The power supply circuit supplies power to the system, the core control and processing function performs the circuit composition output control function, the signal acquisition and control function and the signal processing function perform the waveform measurement, and the data storage and recording unit and the data output function are provided for the comparison and analysis of the waveform when used. The software processing module includes a waveform status display unit and a software control and detection unit, which receives data transmitted from the hardware module, cooperates with the hardware to control output and waveform detection functions, and has interactive functions for data display and analysis; The human-computer interaction module provides an operation interface, allowing the user to input instructions, view real-time data, diagnostic results and historical records on the LCD display, access the system through a remote terminal, and perform monitoring and control operations.

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 a dry-type transformer turn-to-turn insulation fault detection method 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 a dry-type transformer inter-turn insulation fault detection method according to any one of claims 1 to 7 are implemented.

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