Method and system for checking insulation performance of power transformer

Abstract

The invention discloses an insulating property checking method and system for a power transformer, and belongs to the technical field of transformer evaluation. According to the method, the rated insulation margin and the rated allowable electric field intensity are determined, then the real-time electrical performance test result is obtained, the rated allowable electric field intensity is corrected by using the real-time electrical performance test result, and the real-time allowable electric field intensity of each oil gap path is determined. Then, the real-time insulation margin of each oil gap path in the power transformer is determined by using the real-time insulation liquid data and the real-time allowable electric field intensity, and then the real-time insulation margin is searched through a particle algorithm to obtain the real-time global insulation margin of the power transformer; and then carrying out operation risk assessment on the power transformer to determine an insulating property checking result of the power transformer, thereby solving the technical problem of inaccurate checking of the insulating property of the power transformer in the prior art, and improving the accuracy of checking the insulating property of the power transformer.

Description

Technical Field

[0001] This invention belongs to the field of transformer evaluation technology, and in particular relates to a method and system for verifying the insulation performance of power transformers. Background Technology

[0002] As a critical piece of equipment in the power system, the safety and stability of the insulation system of power transformers directly affects the reliability of the power grid. Oil-immersed transformers commonly employ an oil-paper insulation structure, where the insulating fluid not only serves as the key insulating medium but also plays a vital role in heat dissipation, cooling, and optimizing the electric field distribution. During long-term operation, the electrical properties of the insulating fluid gradually change due to aging, moisture absorption, or impurity accumulation, such as decreased dielectric strength and increased dielectric loss. These changes directly affect the overall performance of the insulation system, posing a potential threat to the safe operation and lifespan of the transformer. Therefore, verifying the insulation performance of power transformers has become a crucial step in ensuring the stable operation of power equipment and the reliable power supply from the grid.

[0003] Current insulation performance verification methods for power transformers typically involve taking oil samples for physicochemical property testing, such as moisture content, acid value, and dielectric loss, to assess the health of the insulating fluid. However, these physicochemical parameters do not correspond one-to-one with the actual withstand capability of the insulating fluid under electrical stress, making it difficult to accurately verify the insulation margin of power transformers during operation. Furthermore, the diverse types of insulating fluids used in power transformers, such as mineral oil, natural esters, and synthetic esters, exhibit differences in their electrical performance variation patterns and insulation design, leading to varying impacts on the insulation performance of power transformers and further exacerbating the inaccuracies in insulation performance verification. Summary of the Invention

[0004] This invention aims to provide a method and system for verifying the insulation performance of power transformers to solve the aforementioned technical problems. By correcting the rated allowable electric field strength using real-time electrical performance test results, the real-time allowable electric field strength is obtained. Then, the real-time insulation margin is calculated using the real-time allowable electric field strength and real-time insulating fluid data, thereby realizing the operational risk assessment of power transformers and obtaining the insulation performance verification results of power transformers, thus improving the accuracy of insulation performance verification of power transformers.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a method for verifying the insulation performance of a power transformer, comprising: Obtain the rated operating parameters of the power transformer, and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters; The real-time electrical performance test results of the power transformer during operation are obtained, and the rated allowable electric field strength is corrected based on the real-time electrical performance test results to determine the real-time allowable electric field strength of each oil gap path. Real-time insulating fluid data of the power transformer during operation is collected, and based on the real-time insulating fluid data and the real-time allowable electric field strength, the real-time insulation margin of each oil gap path in the power transformer is determined. The real-time global insulation margin of the power transformer is determined by searching the real-time insulation margin using a preset particle algorithm. An operational risk assessment of the power transformer is conducted based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, thereby determining the insulation performance verification result of the power transformer.

[0006] Understandably, compared to existing technologies, this invention determines the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters of the power transformer. Then, it obtains the real-time electrical performance test results of the power transformer during operation and uses these results to correct the rated allowable electric field strength, thus determining the real-time allowable electric field strength for each oil gap path. This correction of the real-time electrical performance test results ensures that the physicochemical parameter of the real-time allowable electric field strength corresponds to the actual withstand capability of the insulating fluid under electrical stress, thereby enabling the real-time allowable electric field strength to more accurately characterize the actual operating conditions of the insulating fluid under actual electrical stress. Subsequently, the real-time insulation margin of each oil gap path in the power transformer is determined using real-time insulating fluid data and the real-time allowable electric field strength, making the real-time insulation margin more accurate based on these data. Next, a particle algorithm is used to search for the real-time insulation margin. This algorithm can account for the different impacts on the insulation performance of the power transformer caused by variations in the electrical performance of different insulating fluids and differences in insulation design. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global insulation performance. Finally, the operational risk assessment of the power transformer is performed using the real-time global insulation margin and the rated insulation margin of each oil gap path to determine the insulation performance verification result, thus achieving accurate insulation performance verification of the power transformer.

[0007] As a preferred embodiment, obtaining the rated operating parameters of the power transformer and determining the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters includes: The rated operating parameters of the power transformer are obtained, and the power transformer is simulated by finite element method based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

[0008] In the above scheme, an initial two-dimensional axisymmetric electrostatic field model is obtained through finite element simulation using the rated operating parameters of the power transformer. This finite element simulation transforms the abstract transformer insulation structure into a computable initial two-dimensional axisymmetric electrostatic field model. Next, simulation is performed using this initial two-dimensional axisymmetric electrostatic field model, allowing quantification of the electric field strength at each point along each oil gap path in the power transformer, thus obtaining the cumulative average electric field strength. Subsequently, the rated allowable electric field strength is determined using a transformer insulation algorithm, and the rated insulation margin is obtained by combining the cumulative average electric field strength. Quantifying the rated insulation performance of the power transformer through finite element simulation provides an accurate benchmark for subsequent insulation performance verification during operation.

[0009] As a preferred embodiment, the step of obtaining the real-time electrical performance test results of the power transformer during operation, and correcting the rated allowable electric field strength based on the real-time electrical performance test results to determine the real-time allowable electric field strength for each oil gap path includes: The real-time electrical performance test results of the power transformer during operation are obtained, and the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer are determined based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

[0010] In the above scheme, real-time electrical performance test results of the power transformer during operation are obtained, and correction coefficients for power frequency condition and lightning impulse condition are determined based on these results. Then, the power frequency condition correction coefficient and lightning impulse condition correction coefficient are screened based on the voltage condition of the power transformer during operation to determine the dynamic correction coefficient for each oil gap path. This ensures that the dynamic correction coefficient adapts to the actual operating conditions of the power transformer, thereby improving the accuracy of the correction for the rated allowable electric field strength. This, in turn, improves the accuracy of the real-time allowable electric field strength of the oil gap path, ensuring that this physicochemical parameter corresponds to the actual withstand capability of the insulating fluid under electrical stress.

[0011] As a preferred embodiment, the step of obtaining the real-time electrical performance test results of the power transformer during operation, and determining the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results, includes: Lightning impulse breakdown voltage test and power frequency partial discharge initiation voltage test are performed on the power transformer in operation to obtain the real-time electrical performance test results of the power transformer during operation; wherein, the real-time electrical performance test results include: real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage; Obtain the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer; Based on the ratio of the real-time lightning impulse breakdown voltage to the rated lightning impulse breakdown voltage, the lightning impulse condition correction coefficient of the power transformer is determined. The power frequency operating condition correction coefficient of the power transformer is determined based on the ratio of the real-time power frequency partial discharge initiation voltage to the rated power frequency partial discharge initiation voltage.

[0012] In the above scheme, by conducting lightning impulse breakdown voltage tests and power frequency partial discharge initiation voltage tests on the power transformer in operation, the real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage are obtained. Then, the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer at the factory setting are obtained. By using a ratio, the retention rate or attenuation rate of the power transformer under different voltage conditions relative to its original healthy state can be intuitively and accurately quantified. This improves the accuracy of the correction to the rated allowable electric field strength, and further improves the accuracy of the real-time allowable electric field strength of the oil gap path, ensuring that this physicochemical parameter of real-time allowable electric field strength corresponds to the actual withstand capability of the insulating fluid under electrical stress.

[0013] As a preferred embodiment, the step of collecting real-time insulating fluid data of the power transformer during operation, and determining the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength, includes: Real-time insulating fluid data of the power transformer during operation is collected, and the initial two-dimensional axisymmetric electrostatic field model is updated based on the real-time insulating fluid data to obtain the first two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the first two-dimensional axisymmetric electrostatic field model to determine the real-time electric field intensity at each location point in each oil gap path of the power transformer. Based on the real-time electric field intensity at each location point in each oil gap path, the real-time cumulative average electric field intensity of each oil gap path is determined; The real-time insulation margin of each oil gap path is determined based on the real-time allowable electric field strength and the real-time cumulative average electric field strength of each oil gap path.

[0014] In the above scheme, real-time insulating fluid data of the power transformer during operation is collected, and the initial two-dimensional axisymmetric electrostatic field model is updated based on this data. This allows the first two-dimensional axisymmetric electrostatic field model to accurately characterize the operating conditions of the power transformer during operation. Next, the simulation is repeated using the first two-dimensional axisymmetric electrostatic field model to obtain the real-time electric field intensity at each point along each oil gap path in the power transformer, thus obtaining the real-time cumulative average electric field intensity of the oil gap path. Finally, by using the real-time allowable electric field intensity and the real-time cumulative average electric field intensity, the real-time insulation margin not only reflects the actual condition of the insulating fluid during power transformer operation but also reflects the actual withstand capability of the insulating fluid under electrical stress, as well as the physicochemical parameter of the real-time allowable electric field intensity. This improves the accuracy of the real-time insulation margin and consequently enhances the accuracy of subsequent insulation performance verification of the power transformer.

[0015] As a preferred embodiment, the step of searching for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer includes: Obtain a particle swarm and initialize each particle in the particle swarm based on the first two-dimensional axisymmetric electrostatic field model; The fitness function is initialized based on the real-time insulation margin, the historical optimal position of each particle, and the global optimal position of the particle swarm. Based on the historical best position of each particle and the global best position of the particle swarm, construct the velocity update function and position update function for each particle; Based on the fitness function, the velocity update function for each particle, and the position update function, the position and velocity of each particle are iteratively updated to update the historical optimal position of each particle, and then the global optimal position of the particle swarm is updated until a preset number of iterations is reached to complete the update of the global optimal position; the real-time global insulation margin of the power transformer is determined based on the updated global optimal position. Specifically, during each update, based on the updated position and velocity of each particle, the real-time insulation margin corresponding to the current update of each particle is determined; the real-time insulation margin corresponding to the current update of each particle is compared with the real-time insulation margin corresponding to the historical best position, and the historical best position of each particle is updated based on the comparison result; based on the updated historical best position of each particle, the global best position of the particle swarm is updated.

[0016] In the above scheme, the real-time insulation margin is searched using a particle algorithm. This can take into account the different effects on the insulation performance of power transformers caused by the differences in the electrical performance variation patterns and insulation design of different insulating liquids. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance in the complex insulation structure, thereby improving the accuracy of the global characterization of insulation performance.

[0017] As a preferred embodiment, the operational risk assessment of the power transformer based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, to determine the insulation performance verification result of the power transformer, includes: Obtain the insulation margin threshold of the power transformer; If the real-time global insulation margin of the power transformer is greater than the insulation margin threshold, then the insulation performance verification result of the power transformer is determined to be insulation safe. If the real-time global insulation margin of the power transformer is less than or equal to the insulation margin threshold, then each oil gap path is repaired based on the rated insulation margin of each oil gap path, and the insulation performance verification result of the power transformer is determined to be unsafe.

[0018] In the above scheme, by comparing the real-time global insulation margin with the insulation margin threshold, if the real-time global insulation margin is greater than the insulation margin threshold, the insulation performance verification result of the power transformer is determined to be safe; otherwise, each oil gap path is repaired by the rated insulation margin of the oil gap path, thereby achieving a comprehensive and accurate verification of the insulation performance of the power transformer.

[0019] Accordingly, this invention provides an insulation performance verification system for power transformers, including: a rated data acquisition module, a real-time allowable electric field strength acquisition module, a real-time insulation margin acquisition module, a particle algorithm search module, and an insulation performance verification result acquisition module; The rated data acquisition module is used to acquire the rated operating parameters of the power transformer and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters. The real-time allowable electric field strength acquisition module is used to acquire the real-time electrical performance test results of the power transformer during operation, and to correct the rated allowable electric field strength based on the real-time electrical performance test results, thereby determining the real-time allowable electric field strength of each oil gap path. The real-time insulation margin acquisition module is used to collect real-time insulating fluid data of the power transformer during operation, and determine the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength. The particle algorithm search module is used to search for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer. The insulation performance verification result acquisition module is used to perform an operational risk assessment on the power transformer based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, and to determine the insulation performance verification result of the power transformer.

[0020] As a preferred embodiment, the rated data acquisition module includes: a rated data acquisition unit; The rated data acquisition unit is used to acquire the rated operating parameters of the power transformer, and to perform finite element simulation on the power transformer based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

[0021] As a preferred embodiment, the real-time allowable electric field strength acquisition module includes: a real-time allowable electric field strength acquisition unit; The real-time allowable electric field strength acquisition unit is used to acquire the real-time electrical performance test results of the power transformer during operation, and to determine the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

[0022] Understandably, compared to existing technologies, this system determines the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters of the power transformer. Then, it acquires the real-time electrical performance test results of the power transformer during operation and uses these results to correct the rated allowable electric field strength, thus determining the real-time allowable electric field strength for each oil gap path. This correction ensures that the real-time allowable electric field strength, a physicochemical parameter, corresponds to the actual withstand capability of the insulating fluid under electrical stress, thereby enabling a more accurate characterization of the actual operating conditions of the insulating fluid under actual electrical stress. Subsequently, the real-time insulation margin of each oil gap path in the power transformer is determined using real-time insulating fluid data and the real-time allowable electric field strength, making the real-time insulation margin more accurate. Next, a particle algorithm is used to search for the real-time insulation margin. This algorithm can account for the different impacts on the insulation performance of the power transformer caused by variations in the electrical performance of different insulating fluids and differences in insulation design. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global insulation performance. Finally, the operational risk assessment of the power transformer is performed using the real-time global insulation margin and the rated insulation margin of each oil gap path to determine the insulation performance verification result, thus achieving accurate insulation performance verification of the power transformer. Attached Figure Description

[0023] Figure 1 A flowchart illustrating the steps of a method for verifying the insulation performance of a power transformer, as provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an insulation performance verification system for a power transformer, provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 To address the issue of inaccurate insulation performance verification of power transformers in existing technologies, please refer to... Figure 1 , Figure 1 The flowchart of the insulation performance verification method for a power transformer provided in this embodiment of the invention includes steps S101 to S105.

[0026] Step S101: Obtain the rated operating parameters of the power transformer, and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters.

[0027] Step S102: Obtain the real-time electrical performance test results of the power transformer during operation, and correct the rated allowable electric field strength based on the real-time electrical performance test results to determine the real-time allowable electric field strength of each oil gap path.

[0028] Step S103: Collect real-time insulating fluid data of the power transformer during operation, and determine the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength.

[0029] Step S104: Search the real-time insulation margin according to the preset particle algorithm to determine the real-time global insulation margin of the power transformer.

[0030] Step S105: Based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, perform an operational risk assessment on the power transformer and determine the insulation performance verification result of the power transformer.

[0031] In this embodiment, obtaining the rated operating parameters of the power transformer and determining the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters includes: The rated operating parameters of the power transformer are obtained, and the power transformer is simulated by finite element method based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

[0032] In an optional embodiment, the power transformer is set as an oil-immersed transformer, and the rated operating parameters of the power transformer are obtained. These rated operating parameters include the material parameters of the windings, core, solid insulation material, and insulating fluid. Specifically, the rated operating parameters also include the relative permittivity of the insulating fluid and solid insulation material. Finally, using the rated operating parameters and the power transformer's design drawings, a finite element simulation is performed in finite element simulation software (such as ANSYS, SIMULIA, etc.) to establish an initial two-dimensional axisymmetric electrostatic field model. Notably, since finite element simulation technology is already relatively mature, this embodiment will not elaborate on it further.

[0033] Next, the initial two-dimensional axisymmetric electrostatic field model is simulated in finite element simulation software to calculate the electric field distribution of the power transformer under power frequency overvoltage and lightning impulse overvoltage. Then, multiple oil gaps are selected in the main insulation of the power transformer, and multiple oil gap paths are selected along the electric field direction in each oil gap. In this embodiment, the set of position points on one oil gap path is defined as follows: ; Indicates the first One location point; The total number of location points; the distance between adjacent location points is defined as: Since the electric field distribution under power frequency overvoltage and lightning impulse overvoltage has been determined, the electric field intensity at each location point can be directly obtained, denoted as . Then, the cumulative average electric field strength for each of the oil gap paths is calculated. The formula for calculating the cumulative average electric field strength is as follows: .

[0034] Next, the transformer insulation algorithm was set to the Weidmann allowable field strength curve formula, and the rated allowable electric field strength for each oil gap path was calculated using the Weidmann allowable field strength curve formula. Among them, the rated allowable electric field strength of the oil gap path between the insulating paperboards of the power transformer under power frequency voltage (corresponding to power frequency overvoltage) is... for The rated allowable electric field strength of the oil gap path between the insulating paperboard and the windings of a power transformer under power frequency voltage. for The rated allowable electric field strength of the oil gap path between the insulating paperboards of a power transformer under lightning impulse voltage (corresponding to lightning impulse overvoltage). for The rated allowable electric field strength of the oil gap path between the insulating paperboard and the windings of a power transformer under lightning impulse voltage. for ; Finally, the rated insulation margin for each oil gap path. It is calculated using the rated allowable electric field strength and the cumulative average electric field strength. The calculation process is as follows: Specifically, the rated allowable electric field strength under power frequency voltage is divided by the cumulative average electric field strength under power frequency overvoltage to obtain the rated insulation margin under power frequency voltage; the rated allowable electric field strength under lightning impulse voltage is divided by the cumulative average electric field strength under lightning impulse overvoltage to obtain the rated insulation margin under lightning impulse voltage.

[0035] It should be noted that main insulation refers to the insulation system between transformer windings and between windings and grounding, which includes solid insulation (such as cardboard and support bars) and insulating fluid (oil gap). The main insulation oil gap specifically refers to the area filled with insulating fluid within the main insulation, i.e., the oil gap portion. An oil gap path is a continuous line segment selected along the electric field direction in the oil gap for insulation margin calculation in electric field simulation, used to calculate the cumulative average electric field strength along this path. Multiple oil gap paths can be selected for verification within a single oil gap to cover potentially weak areas. The Wiedemann allowable field strength curve formula (Wiedemann-Schwarz principle) is based on the Wiedemann-Schwarz principle in high-voltage insulation design. It states that for a coaxial cylindrical electrode structure, when the ratio of the inner conductor radius to the outer conductor radius is 1 / e ≈ 0.368, the maximum electric field strength in the insulation layer reaches its minimum value, at which point the electric field distribution is most uniform, and the utilization rate of the insulation material is highest.

[0036] In the above embodiments, an initial two-dimensional axisymmetric electrostatic field model is obtained through finite element simulation using the rated operating parameters of the power transformer. This finite element simulation transforms the abstract transformer insulation structure into a computable initial two-dimensional axisymmetric electrostatic field model. Next, simulation is performed using this initial two-dimensional axisymmetric electrostatic field model, allowing quantification of the electric field strength at each point along each oil gap path in the power transformer, thus obtaining the cumulative average electric field strength. Subsequently, the rated allowable electric field strength is determined using a transformer insulation algorithm, and the rated insulation margin is obtained by combining the cumulative average electric field strength. Quantifying the rated insulation performance of the power transformer through finite element simulation provides an accurate benchmark for subsequent insulation performance verification during operation.

[0037] In this embodiment, obtaining the real-time electrical performance test results of the power transformer during operation, and correcting the rated allowable electric field strength based on the real-time electrical performance test results to determine the real-time allowable electric field strength for each oil gap path includes: The real-time electrical performance test results of the power transformer during operation are obtained, and the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer are determined based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

[0038] In the above embodiments, real-time electrical performance test results of the power transformer during operation are obtained, and correction coefficients for power frequency operation and lightning impulse operation under two different key operating conditions are determined based on these results. Then, the power frequency operation correction coefficients and lightning impulse operation correction coefficients are screened based on the voltage conditions of the power transformer during operation to determine the dynamic correction coefficient for each oil gap path. This ensures that the dynamic correction coefficient adapts to the actual operating conditions of the power transformer, thereby improving the accuracy of the correction for the rated allowable electric field strength. This, in turn, improves the accuracy of the real-time allowable electric field strength of the oil gap path, ensuring that this physicochemical parameter of real-time allowable electric field strength corresponds to the actual withstand capability of the insulating fluid under electrical stress.

[0039] In this embodiment, obtaining the real-time electrical performance test results of the power transformer during operation, and determining the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results, includes: Lightning impulse breakdown voltage test and power frequency partial discharge initiation voltage test are performed on the power transformer in operation to obtain the real-time electrical performance test results of the power transformer during operation; wherein, the real-time electrical performance test results include: real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage; Obtain the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer; Based on the ratio of the real-time lightning impulse breakdown voltage to the rated lightning impulse breakdown voltage, the lightning impulse condition correction coefficient of the power transformer is determined. The power frequency operating condition correction coefficient of the power transformer is determined based on the ratio of the real-time power frequency partial discharge initiation voltage to the rated power frequency partial discharge initiation voltage.

[0040] In the above embodiments, by performing lightning impulse breakdown voltage tests and power frequency partial discharge initiation voltage tests on the power transformer in operation, the real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage are obtained. Next, the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer at the factory setting are obtained. By using a ratio, the retention rate or attenuation rate of the power transformer relative to its original healthy state under different voltage conditions can be intuitively and accurately quantified. This improves the accuracy of the correction to the rated allowable electric field strength, and further improves the accuracy of the real-time allowable electric field strength of the oil gap path, ensuring that this physicochemical parameter of real-time allowable electric field strength corresponds to the actual withstand capability of the insulating fluid under electrical stress.

[0041] In one optional embodiment, lightning impulse breakdown voltage and power frequency partial discharge initiation voltage tests are performed on the power transformer in operation. The lightning impulse breakdown voltage test is conducted according to the IEC 60897 standard, using a standard lightning impulse voltage waveform to break down the insulating fluid. The test is repeated at least 10 times, and the arithmetic mean is taken after removing outliers as the real-time lightning impulse breakdown voltage of the insulating fluid under lightning impulse. The power frequency partial discharge initiation voltage test was conducted according to the IEC 1294 standard. Power frequency AC voltage was used for boosting. When the apparent discharge quantity reached 100 pC, the corresponding voltage value was recorded as the partial discharge initiation voltage. The test was repeated at least 10 times. After removing outliers, the arithmetic mean was taken as the real-time power frequency partial discharge initiation voltage of the insulating fluid. Furthermore, before the power transformer is put into operation, lightning impulse breakdown voltage and power frequency partial discharge initiation voltage tests are performed on the power transformer to obtain the rated lightning impulse breakdown voltage. and rated power frequency partial discharge initiation voltage ; Next, the ratio of the real-time lightning impulse breakdown voltage to the rated lightning impulse breakdown voltage is used as the lightning impulse operating condition correction factor for the power transformer. The calculation process is as follows: The ratio of the real-time power frequency partial discharge initiation voltage to the rated power frequency partial discharge initiation voltage is used as the power frequency operating condition correction factor for the power transformer. The calculation process is as follows: ; Specifically, if the real-time power frequency partial discharge initiation voltage cannot be obtained under actual operating conditions, a power frequency breakdown voltage test is used instead. In this case, a power frequency breakdown voltage test is performed on the power transformer to obtain the rated power frequency breakdown voltage. and real-time power frequency breakdown voltage Then the power frequency correction factor at this time for: .

[0042] Next, the voltage conditions of the power transformer during operation are obtained, including power frequency overvoltage and lightning impulse overvoltage. If it is a lightning impulse overvoltage, a correction factor for the lightning impulse condition is selected. As a dynamic correction coefficient for the oil gap path If it is a power frequency overvoltage, then select the power frequency operating condition correction factor. As a dynamic correction coefficient for the oil gap path ; Finally, the rated allowable electric field strength is corrected by a dynamic correction coefficient to obtain the real-time allowable electric field strength for each oil gap path. The correction process is represented as follows: .

[0043] In this embodiment, the step of collecting real-time insulating fluid data of the power transformer during operation, and determining the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength, includes: Real-time insulating fluid data of the power transformer during operation is collected, and the initial two-dimensional axisymmetric electrostatic field model is updated based on the real-time insulating fluid data to obtain the first two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the first two-dimensional axisymmetric electrostatic field model to determine the real-time electric field intensity at each location point in each oil gap path of the power transformer. Based on the real-time electric field intensity at each location point in each oil gap path, the real-time cumulative average electric field intensity of each oil gap path is determined; The real-time insulation margin of each oil gap path is determined based on the real-time allowable electric field strength and the real-time cumulative average electric field strength of each oil gap path.

[0044] In one optional embodiment, real-time insulating fluid data of the power transformer during operation is acquired. This real-time insulating fluid data refers to the relative permittivity of the insulating fluid during operation. Then, the parameters of the initial two-dimensional axisymmetric electrostatic field model are updated in finite element simulation software to obtain a first two-dimensional axisymmetric electrostatic field model. Subsequently, the electric field distribution of the power transformer under power frequency overvoltage and lightning impulse overvoltage is recalculated in the first two-dimensional axisymmetric electrostatic field model, thereby calculating the real-time electric field strength at each location point in each oil gap path, and subsequently calculating the real-time cumulative average electric field strength of the oil gap path. Finally, the real-time insulation margin of each oil gap path is determined by the real-time allowable electric field strength and the real-time cumulative average electric field strength. The calculation process for real-time insulation margin is as follows: .

[0045] In the above embodiments, by collecting real-time insulating fluid data of the power transformer during operation, and updating the initial two-dimensional axisymmetric electrostatic field model based on the real-time insulating fluid data, the first two-dimensional axisymmetric electrostatic field model can accurately characterize the operating conditions of the power transformer during operation. Next, the simulation is repeated using the first two-dimensional axisymmetric electrostatic field model to obtain the real-time electric field intensity at each location point in each oil gap path of the power transformer, thereby obtaining the real-time cumulative average electric field intensity of the oil gap path. Finally, through the real-time allowable electric field intensity and the real-time cumulative average electric field intensity, the real-time insulation margin not only reflects the actual situation of the insulating fluid during the operation of the power transformer, but also reflects the actual withstand capability of the insulating fluid under electrical stress, as well as the physicochemical parameter of the real-time allowable electric field intensity. This improves the accuracy of the real-time insulation margin, and consequently improves the accuracy of subsequent insulation performance verification of the power transformer.

[0046] In this embodiment, the step of searching for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer includes: Obtain a particle swarm and initialize each particle in the particle swarm based on the first two-dimensional axisymmetric electrostatic field model; The fitness function is initialized based on the real-time insulation margin, the historical optimal position of each particle, and the global optimal position of the particle swarm. Based on the historical best position of each particle and the global best position of the particle swarm, construct the velocity update function and position update function for each particle; Based on the fitness function, the velocity update function for each particle, and the position update function, the position and velocity of each particle are iteratively updated to update the historical optimal position of each particle, and then the global optimal position of the particle swarm is updated until a preset number of iterations is reached to complete the update of the global optimal position; the real-time global insulation margin of the power transformer is determined based on the updated global optimal position. Specifically, during each update, based on the updated position and velocity of each particle, the real-time insulation margin corresponding to the current update of each particle is determined; the real-time insulation margin corresponding to the current update of each particle is compared with the real-time insulation margin corresponding to the historical best position, and the historical best position of each particle is updated based on the comparison result; based on the updated historical best position of each particle, the global best position of the particle swarm is updated.

[0047] In an optional embodiment, a particle swarm is obtained; in this embodiment, the number of particles in the particle swarm is set to... The position of each particle is initialized using the spatial coordinate sequence (radial and axial positions) of the oil gap path in the first two-dimensional axisymmetric electrostatic field model. The speed of the particles This indicates the update direction and step size of the oil gap path during iteration (its initial value can be set according to actual conditions).

[0048] At this point, one particle represents one oil gap path. The historical optimal position of the particle is initialized using the real-time insulation margin of the oil gap path at this time. The global optimal position of the particle swarm The fitness function is initialized to 0. ;in, Indicates the first Real-time insulation margin of the oil gap path corresponding to each particle; Minimize .

[0049] Next, based on the historical optimal position of each particle and the global optimal position of the particle swarm, a velocity update function and a position update function are constructed for each particle. The velocity update function is shown in Equation (1), and the position update function is shown in Equation (2); where, Indicates the first The next iteration; For individual learning factors, ; As a social learning factor, ; The inertial weight is initially set to 0.9, and its value decreases linearly to 0.4 with each iteration. and A uniformly random number within the range [0,1]; Indicates the first During the nth iteration The velocity of each particle; Indicates the first During the nth iteration The velocity of each particle; Indicates the first During the nth iteration The position of each particle; Indicates the first During the nth iteration The position of each particle; (1); (2); The preset number of iterations is Based on the fitness function, the velocity update function for each particle, and the position update function, the position and velocity of each particle are iteratively updated. At each update, the real-time insulation margin corresponding to the current update of each particle is determined based on the updated position and velocity. Then, the real-time insulation margin corresponding to the current update of each particle is compared. Real-time insulation margin corresponding to the historical best position The comparison result is obtained; if the comparison result is the real-time insulation margin corresponding to the current update, then... The real-time insulation margin is less than the historical best position. Then the historical best position will be updated to the particle's current updated position. Otherwise, the historical optimal position remains unchanged, and the specific update process is shown in formula (3). Next, based on the real-time insulation margin corresponding to the updated historical optimal position of each particle, the position with the smallest value is selected as the global optimal position, and the specific update process is shown in formula (4).

[0050] (3); (4); When the preset number of iterations is reached When the time is reached, the particle algorithm terminates, completing the update of the global optimal position. The oil gap path corresponding to the updated global optimal position is represented as: At this point, the real-time insulation margin of the oil gap path corresponding to the updated global optimal position is the real-time global insulation margin of the power transformer. .

[0051] In the above embodiments, by using a particle algorithm to search for the real-time insulation margin, the different effects of varying electrical performance patterns and insulation design of different insulating liquids on the insulation performance of power transformers can be considered. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global characterization of insulation performance.

[0052] In this embodiment, the step of assessing the operational risk of the power transformer based on its real-time global insulation margin and the rated insulation margin of each oil gap path, and determining the insulation performance verification result of the power transformer, includes: Obtain the insulation margin threshold of the power transformer; If the real-time global insulation margin of the power transformer is greater than the insulation margin threshold, then the insulation performance verification result of the power transformer is determined to be insulation safe. If the real-time global insulation margin of the power transformer is less than or equal to the insulation margin threshold, then each oil gap path is repaired based on the rated insulation margin of each oil gap path, and the insulation performance verification result of the power transformer is determined to be unsafe.

[0053] In one optional embodiment, the insulation margin threshold of the power transformer is set to 1; if the real-time global insulation margin of the power transformer is greater than the insulation margin threshold, i.e. If the current insulation performance verification result of the power transformer under the current operating conditions is satisfactory, then the insulation is safe. If the real-time global insulation margin of the power transformer is less than or equal to the insulation margin threshold, then the insulation is not safe. This indicates that the insulation performance verification result of the power transformer under the current operating conditions is that the insulation is unsafe; at this time, the minimum value is selected from the rated insulation margin as the main insulation insulation margin of the power transformer under rated conditions. Then, intervention measures are taken for the power transformer, including filtering the insulating fluid or replacing it with new insulating fluid. After taking intervention measures, steps S102 to S104 above are repeated to recalculate the real-time global insulation margin. If the recalculated real-time global insulation margin is less than the main insulation margin... If the insulation performance verification result is negative, then the insulation safety result will be changed.

[0054] In the above embodiments, by comparing the real-time global insulation margin with the insulation margin threshold, if the real-time global insulation margin is greater than the insulation margin threshold, the insulation performance verification result of the power transformer is determined to be safe; otherwise, each oil gap path is repaired by the rated insulation margin of the oil gap path, thereby achieving a comprehensive and accurate verification of the insulation performance of the power transformer.

[0055] This embodiment determines the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters of the power transformer. Then, it acquires the real-time electrical performance test results of the power transformer during operation and uses these results to correct the rated allowable electric field strength, thus determining the real-time allowable electric field strength for each oil gap path. This correction ensures that the real-time allowable electric field strength, a physicochemical parameter, corresponds to the actual withstand capability of the insulating fluid under electrical stress, thereby enabling a more accurate characterization of the actual operating conditions of the insulating fluid under actual electrical stress. Subsequently, the real-time insulation margin of each oil gap path in the power transformer is determined using real-time insulating fluid data and the real-time allowable electric field strength, further enhancing the accuracy of the real-time insulation margin. Next, a particle algorithm is used to search for the real-time insulation margin. This algorithm can account for the different impacts on the insulation performance of the power transformer caused by variations in the electrical performance of different insulating fluids and differences in insulation design. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global insulation performance. Finally, the operational risk assessment of the power transformer is performed using the real-time global insulation margin and the rated insulation margin of each oil gap path to determine the insulation performance verification result, thus achieving accurate insulation performance verification of the power transformer.

[0056] Example 2 Please refer to Figure 2 , Figure 2 A schematic diagram of the structure of an insulation performance verification system for a power transformer provided in an embodiment of the present invention includes: a rated data acquisition module 201, a real-time allowable electric field strength acquisition module 202, a real-time insulation margin acquisition module 203, a particle algorithm search module 204, and an insulation performance verification result acquisition module 205; The rated data acquisition module 201 is used to acquire the rated operating parameters of the power transformer and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters. The real-time allowable electric field strength acquisition module 202 is used to acquire the real-time electrical performance test results of the power transformer during operation, and to correct the rated allowable electric field strength based on the real-time electrical performance test results, thereby determining the real-time allowable electric field strength of each oil gap path. The real-time insulation margin acquisition module 203 is used to collect real-time insulation fluid data of the power transformer during operation, and determine the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulation fluid data and the real-time allowable electric field strength. The particle algorithm search module 204 is used to search for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer. The insulation performance verification result acquisition module 205 is used to perform an operational risk assessment on the power transformer based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, and to determine the insulation performance verification result of the power transformer.

[0057] In this embodiment, the rated data acquisition module 201 includes: a rated data acquisition unit; The rated data acquisition unit is used to acquire the rated operating parameters of the power transformer, and to perform finite element simulation on the power transformer based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

[0058] In this embodiment, the real-time allowable electric field strength acquisition module 202 includes: a real-time allowable electric field strength acquisition unit; The real-time allowable electric field strength acquisition unit is used to acquire the real-time electrical performance test results of the power transformer during operation, and to determine the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

[0059] In this embodiment, the real-time allowable electric field strength acquisition unit includes: a real-time electrical performance test result acquisition subunit; The real-time electrical performance test result acquisition subunit is used to perform lightning impulse breakdown voltage test and power frequency partial discharge initiation voltage test on the power transformer in operation, and acquire the real-time electrical performance test results of the power transformer in operation; wherein, the real-time electrical performance test results include: real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage; Obtain the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer; Based on the ratio of the real-time lightning impulse breakdown voltage to the rated lightning impulse breakdown voltage, the lightning impulse condition correction coefficient of the power transformer is determined. The power frequency operating condition correction coefficient of the power transformer is determined based on the ratio of the real-time power frequency partial discharge initiation voltage to the rated power frequency partial discharge initiation voltage.

[0060] In this embodiment, the real-time insulation margin acquisition module 203 includes: a real-time insulation margin acquisition unit; The real-time insulation margin acquisition unit is used to collect real-time insulating fluid data of the power transformer during operation, and update the initial two-dimensional axisymmetric electrostatic field model based on the real-time insulating fluid data to obtain the first two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the first two-dimensional axisymmetric electrostatic field model to determine the real-time electric field intensity at each location point in each oil gap path of the power transformer. Based on the real-time electric field intensity at each location point in each oil gap path, the real-time cumulative average electric field intensity of each oil gap path is determined; The real-time insulation margin of each oil gap path is determined based on the real-time allowable electric field strength and the real-time cumulative average electric field strength of each oil gap path.

[0061] In this embodiment, the particle algorithm search module 204 includes: a particle algorithm search unit; The particle algorithm search unit is used to obtain a particle swarm and initialize each particle in the particle swarm based on the first two-dimensional axisymmetric electrostatic field model. The fitness function is initialized based on the real-time insulation margin, the historical optimal position of each particle, and the global optimal position of the particle swarm. Based on the historical best position of each particle and the global best position of the particle swarm, construct the velocity update function and position update function for each particle; Based on the fitness function, the velocity update function for each particle, and the position update function, the position and velocity of each particle are iteratively updated to update the historical optimal position of each particle, and then the global optimal position of the particle swarm is updated until a preset number of iterations is reached to complete the update of the global optimal position; the real-time global insulation margin of the power transformer is determined based on the updated global optimal position. Specifically, during each update, based on the updated position and velocity of each particle, the real-time insulation margin corresponding to the current update of each particle is determined; the real-time insulation margin corresponding to the current update of each particle is compared with the real-time insulation margin corresponding to the historical best position, and the historical best position of each particle is updated based on the comparison result; based on the updated historical best position of each particle, the global best position of the particle swarm is updated.

[0062] In this embodiment, the insulation performance verification result acquisition module 205 includes: an insulation performance verification result acquisition unit; The insulation performance verification result acquisition unit is used to obtain the insulation margin threshold of the power transformer; If the real-time global insulation margin of the power transformer is greater than the insulation margin threshold, then the insulation performance verification result of the power transformer is determined to be insulation safe. If the real-time global insulation margin of the power transformer is less than or equal to the insulation margin threshold, then each oil gap path is repaired based on the rated insulation margin of each oil gap path, and the insulation performance verification result of the power transformer is determined to be unsafe.

[0063] This embodiment determines the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters of the power transformer. Then, it acquires the real-time electrical performance test results of the power transformer during operation and uses these results to correct the rated allowable electric field strength, thus determining the real-time allowable electric field strength for each oil gap path. This correction ensures that the real-time allowable electric field strength, a physicochemical parameter, corresponds to the actual withstand capability of the insulating fluid under electrical stress, thereby enabling a more accurate characterization of the actual operating conditions of the insulating fluid under actual electrical stress. Subsequently, the real-time insulation margin of each oil gap path in the power transformer is determined using real-time insulating fluid data and the real-time allowable electric field strength, further enhancing the accuracy of the real-time insulation margin. Next, a particle algorithm is used to search for the real-time insulation margin. This algorithm can account for the different impacts on the insulation performance of the power transformer caused by variations in the electrical performance of different insulating fluids and differences in insulation design. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global insulation performance. Finally, the operational risk assessment of the power transformer is performed using the real-time global insulation margin and the rated insulation margin of each oil gap path to determine the insulation performance verification result, thus achieving accurate insulation performance verification of the power transformer.

[0064] In summary, this embodiment of the invention determines the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters of the power transformer. Then, it obtains the real-time electrical performance test results of the power transformer during operation and uses these results to correct the rated allowable electric field strength, thus determining the real-time allowable electric field strength for each oil gap path. This correction of the real-time electrical performance test results ensures that the physicochemical parameter of the real-time allowable electric field strength corresponds to the actual withstand capability of the insulating fluid under electrical stress, thereby enabling the real-time allowable electric field strength to more accurately characterize the actual operating conditions of the insulating fluid under actual electrical stress. Subsequently, the real-time insulation margin of each oil gap path in the power transformer is determined using real-time insulating fluid data and the real-time allowable electric field strength, making the real-time insulation margin more accurate based on these parameters. Next, a particle algorithm is used to search for the real-time insulation margin. This algorithm can account for the different impacts on the insulation performance of the power transformer caused by variations in the electrical performance of different insulating fluids and differences in insulation design. This allows the real-time global insulation margin of the power transformer to accurately characterize the weakest link in the overall insulation performance within the complex insulation structure, thereby improving the accuracy of the global insulation performance. Finally, the operational risk assessment of the power transformer is performed using the real-time global insulation margin and the rated insulation margin of each oil gap path to determine the insulation performance verification result, thus achieving accurate insulation performance verification of the power transformer.

[0065] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for verifying the insulation performance of a power transformer, characterized in that, include: Obtain the rated operating parameters of the power transformer, and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters; The real-time electrical performance test results of the power transformer during operation are obtained, and the rated allowable electric field strength is corrected based on the real-time electrical performance test results to determine the real-time allowable electric field strength of each oil gap path. Real-time insulating fluid data of the power transformer during operation is collected, and based on the real-time insulating fluid data and the real-time allowable electric field strength, the real-time insulation margin of each oil gap path in the power transformer is determined. The real-time global insulation margin of the power transformer is determined by searching the real-time insulation margin using a preset particle algorithm. An operational risk assessment of the power transformer is conducted based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, thereby determining the insulation performance verification result of the power transformer.

2. The method for verifying the insulation performance of a power transformer as described in claim 1, characterized in that, The process of obtaining the rated operating parameters of the power transformer and determining the rated insulation margin and rated allowable electric field strength for each oil gap path in the power transformer based on the rated operating parameters includes: The rated operating parameters of the power transformer are obtained, and the power transformer is simulated by finite element method based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

3. The method for verifying the insulation performance of a power transformer as described in claim 2, characterized in that, The process of obtaining real-time electrical performance test results of the power transformer during operation, and correcting the rated allowable electric field strength based on the real-time electrical performance test results to determine the real-time allowable electric field strength for each oil gap path includes: The real-time electrical performance test results of the power transformer during operation are obtained, and the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer are determined based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

4. The method for verifying the insulation performance of a power transformer as described in claim 3, characterized in that, The step of obtaining the real-time electrical performance test results of the power transformer during operation, and determining the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results, includes: Lightning impulse breakdown voltage test and power frequency partial discharge initiation voltage test are performed on the power transformer in operation to obtain the real-time electrical performance test results of the power transformer during operation; wherein, the real-time electrical performance test results include: real-time lightning impulse breakdown voltage and real-time power frequency partial discharge initiation voltage; Obtain the rated lightning impulse breakdown voltage and rated power frequency partial discharge initiation voltage of the power transformer; Based on the ratio of the real-time lightning impulse breakdown voltage to the rated lightning impulse breakdown voltage, the lightning impulse condition correction coefficient of the power transformer is determined. The power frequency operating condition correction coefficient of the power transformer is determined based on the ratio of the real-time power frequency partial discharge initiation voltage to the rated power frequency partial discharge initiation voltage.

5. The method for verifying the insulation performance of a power transformer as described in claim 2, characterized in that, The process of collecting real-time insulating fluid data of the power transformer during operation, and determining the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength, includes: Real-time insulating fluid data of the power transformer during operation is collected, and the initial two-dimensional axisymmetric electrostatic field model is updated based on the real-time insulating fluid data to obtain the first two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the first two-dimensional axisymmetric electrostatic field model to determine the real-time electric field intensity at each location point in each oil gap path of the power transformer. Based on the real-time electric field intensity at each location point in each oil gap path, the real-time cumulative average electric field intensity of each oil gap path is determined; The real-time insulation margin of each oil gap path is determined based on the real-time allowable electric field strength and the real-time cumulative average electric field strength of each oil gap path.

6. The method for verifying the insulation performance of a power transformer as described in claim 5, characterized in that, The step of searching for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer includes: Obtain a particle swarm and initialize each particle in the particle swarm based on the first two-dimensional axisymmetric electrostatic field model; The fitness function is initialized based on the real-time insulation margin, the historical optimal position of each particle, and the global optimal position of the particle swarm. Based on the historical best position of each particle and the global best position of the particle swarm, construct the velocity update function and position update function for each particle; Based on the fitness function, the velocity update function for each particle, and the position update function, the position and velocity of each particle are iteratively updated to update the historical optimal position of each particle, and then the global optimal position of the particle swarm is updated until a preset number of iterations is reached to complete the update of the global optimal position; the real-time global insulation margin of the power transformer is determined based on the updated global optimal position. Specifically, during each update, based on the updated position and velocity of each particle, the real-time insulation margin corresponding to the current update of each particle is determined; the real-time insulation margin corresponding to the current update of each particle is compared with the real-time insulation margin corresponding to the historical best position, and the historical best position of each particle is updated based on the comparison result; based on the updated historical best position of each particle, the global best position of the particle swarm is updated.

7. The method for verifying the insulation performance of a power transformer as described in claim 1, characterized in that, The operational risk assessment of the power transformer based on its real-time global insulation margin and the rated insulation margin of each oil gap path, to determine the insulation performance verification results of the power transformer, includes: Obtain the insulation margin threshold of the power transformer; If the real-time global insulation margin of the power transformer is greater than the insulation margin threshold, then the insulation performance verification result of the power transformer is determined to be insulation safe. If the real-time global insulation margin of the power transformer is less than or equal to the insulation margin threshold, then each oil gap path is repaired based on the rated insulation margin of each oil gap path, and the insulation performance verification result of the power transformer is determined to be unsafe.

8. A system for verifying the insulation performance of a power transformer, characterized in that, include: Rated data acquisition module, real-time allowable electric field strength acquisition module, real-time insulation margin acquisition module, particle algorithm search module, and insulation performance verification result acquisition module; The rated data acquisition module is used to acquire the rated operating parameters of the power transformer and determine the rated insulation margin and rated allowable electric field strength of each oil gap path in the power transformer based on the rated operating parameters. The real-time allowable electric field strength acquisition module is used to acquire the real-time electrical performance test results of the power transformer during operation, and to correct the rated allowable electric field strength based on the real-time electrical performance test results, thereby determining the real-time allowable electric field strength of each oil gap path. The real-time insulation margin acquisition module is used to collect real-time insulating fluid data of the power transformer during operation, and determine the real-time insulation margin of each oil gap path in the power transformer based on the real-time insulating fluid data and the real-time allowable electric field strength. The particle algorithm search module is used to search for the real-time insulation margin according to a preset particle algorithm to determine the real-time global insulation margin of the power transformer. The insulation performance verification result acquisition module is used to perform an operational risk assessment on the power transformer based on the real-time global insulation margin of the power transformer and the rated insulation margin of each oil gap path, and to determine the insulation performance verification result of the power transformer.

9. The insulation performance verification system for a power transformer as described in claim 8, characterized in that, The rated data acquisition module includes: a rated data acquisition unit; The rated data acquisition unit is used to acquire the rated operating parameters of the power transformer, and to perform finite element simulation on the power transformer based on the rated operating parameters to obtain an initial two-dimensional axisymmetric electrostatic field model. The electric field distribution of each oil gap path in the power transformer is simulated based on the initial two-dimensional axisymmetric electrostatic field model to determine the electric field intensity at each location point in each oil gap path of the power transformer. Based on the electric field intensity at each location point in each oil gap path, the cumulative average electric field intensity of each oil gap path is determined; The rated allowable electric field strength for each oil gap path is determined based on a preset transformer insulation algorithm; The rated insulation margin of each oil gap path is determined based on the rated allowable electric field strength and the cumulative average electric field strength of each oil gap path.

10. The insulation performance verification system for a power transformer as described in claim 9, characterized in that, The real-time allowable electric field strength acquisition module includes: a real-time allowable electric field strength acquisition unit; The real-time allowable electric field strength acquisition unit is used to acquire the real-time electrical performance test results of the power transformer during operation, and to determine the power frequency condition correction coefficient and lightning impulse condition correction coefficient of the power transformer based on the real-time electrical performance test results. The voltage conditions of the power transformer during operation are obtained, and the correction coefficients for the power frequency condition and the lightning impulse condition are screened based on the voltage conditions to determine the dynamic correction coefficient for each oil gap path. The rated allowable electric field strength is corrected based on the dynamic correction coefficient of each oil gap path to determine the real-time allowable electric field strength of each oil gap path.

Images