A high-voltage direct-current bushing dielectric response diagnosis method and device

Abstract

The specification provides a high-voltage direct-current bushing dielectric response diagnosis method and device. Real measured dielectric response data, outer surface multi-point temperature data, operation condition data and a preset reference condition of a target high-voltage direct-current bushing are acquired. According to the outer surface multi-point temperature data and the operation condition data, an internal temperature gradient description quantity of the target high-voltage direct-current bushing is determined. According to the internal temperature gradient description quantity, the operation condition data and the preset reference condition, the real measured dielectric response data is compensated to determine target dielectric response data under the preset reference condition. According to the target dielectric response data, an insulation state diagnosis result of the target high-voltage direct-current bushing is determined. Thus, the accuracy of the insulation state diagnosis result is improved.

Description

Technical Field

[0001] This manual belongs to the field of power equipment condition monitoring and fault diagnosis technology, and in particular relates to a method and device for diagnosing the dielectric response of high voltage DC bushings. Background Technology

[0002] High-voltage DC bushings are critical insulation components in converter transformers, smoothing reactors, and valve hall wall-penetrating interfaces. Their dielectric response is easily affected by changes in operating conditions. Existing technologies typically use ambient temperature, single-point temperature, or average temperature to correct dielectric response data, which is insufficient to fully characterize the non-uniform temperature distribution inside the high-voltage DC bushing and the differentiated sensitivity of dielectric response in different frequency bands to operating conditions. Consequently, there are problems such as insufficient comparability of dielectric response data under different operating conditions and the insulation condition diagnosis results being easily affected by operating condition disturbances.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This specification provides a method and device for diagnosing the dielectric response of high-voltage DC bushings, which solves the problem of poor comparability of dielectric response data of high-voltage DC bushings under different operating conditions, resulting in insufficient accuracy of insulation condition diagnosis.

[0005] This specification provides a method and apparatus for diagnosing the dielectric response of high-voltage DC bushings, including: Acquire measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference conditions of the target high-voltage DC bushing; Based on the multi-point temperature data of the outer surface and the operating condition data, the internal temperature gradient descriptor of the target high-voltage DC bushing is determined; Based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition, the measured dielectric response data is compensated to determine the target dielectric response data under the preset reference condition. Based on the target dielectric response data, the insulation status diagnosis result of the target high-voltage DC bushing is determined.

[0006] In one embodiment, the operating condition data includes current-carrying current and environmental boundary data. Determining the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data includes: Using a pre-defined segmented thermal network model, the initial temperatures of multiple internal regions of the target high-voltage DC bushing are determined based on the current-carrying current and the environmental boundary data. Based on the multi-point temperature data of the outer surface, the initial temperature corresponding to the multiple internal regions is corrected to determine the temperature of the multiple internal regions; The internal temperature gradient descriptor is determined based on the temperatures of the multiple internal regions.

[0007] In one embodiment, the plurality of internal regions include a plurality of axial regions distributed along the axis of the target high-voltage DC bushing and a plurality of radial regions distributed along the radial direction of the target high-voltage DC bushing. Determining the internal temperature gradient descriptor based on the temperatures of the plurality of internal regions includes: The axial temperature difference is determined based on the temperatures corresponding to the multiple axial regions. The radial temperature difference is determined based on the temperatures corresponding to the multiple radial regions; The equivalent average temperature is determined based on the temperatures of the multiple internal regions. The internal temperature gradient descriptor is determined based on the axial temperature difference, the radial temperature difference, and the equivalent average temperature.

[0008] In one embodiment, the step of compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition includes: Based on the test frequency corresponding to the measured dielectric response data, the measured dielectric response data is divided into multiple frequency band dielectric response data. For each band dielectric response data, compensation parameters corresponding to the band dielectric response data are determined based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition. Using the compensation parameters corresponding to the dielectric response data of each frequency band, the dielectric response data of each frequency band is compensated to determine multiple compensated dielectric response data; The target dielectric response data is determined based on the plurality of compensated dielectric response data.

[0009] In one embodiment, the operating condition data includes current-carrying current and environmental boundary data; when the current-carrying current, the environmental boundary data, and the multi-point temperature data of the outer surface are all within their respective preset effective ranges, and the acquisition duration of the measured dielectric response data is greater than a preset duration or the operating condition stability during the test is lower than a preset stability threshold, the step of compensating the measured dielectric response data according to the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition includes: For each test frequency point in the measured dielectric response data, the frequency point temperature data and frequency point operating condition data corresponding to the test frequency point are determined according to the test time period corresponding to the test frequency point. Based on the frequency point temperature data and the frequency point operating condition data, determine the frequency point temperature gradient descriptor corresponding to the test frequency point; Based on the frequency point temperature gradient descriptor, the frequency point operating condition data, and the preset reference operating condition, determine the frequency point compensation parameters corresponding to the test frequency point, and use the frequency point compensation parameters to compensate the dielectric response corresponding to the test frequency point to determine the frequency point compensation dielectric response. The target dielectric response data is determined based on the frequency point compensation dielectric response corresponding to each of the test frequency points.

[0010] In one embodiment, determining the insulation status diagnostic result of the target high-voltage DC bushing based on the target dielectric response data includes: Obtain the preset health reference dielectric response data corresponding to the target high voltage DC bushing; Based on the target dielectric response data, determine the low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, and high-frequency dielectric response characteristics; Based on the target dielectric response data and the preset healthy reference dielectric response data, the dielectric response residual characteristics are determined; Based on the low-frequency dielectric response characteristics, the mid-frequency dielectric response characteristics, the high-frequency dielectric response characteristics, and the dielectric response residual characteristics, the moisture state index, aging state index, and abnormal state index are determined. The insulation condition diagnosis result is determined based on the moisture condition index, the aging condition index, and the abnormal condition index.

[0011] In one embodiment, the method further includes: Based on the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data, the data integrity and operating condition stability are determined. The compensation parameters corresponding to each of the frequency band dielectric response data are compared with the corresponding preset compensation parameter range, or the frequency point compensation parameters corresponding to each of the test frequency points are compared with the corresponding preset compensation parameter range, and the compensation effectiveness is determined based on the comparison results. The diagnostic confidence level is determined based on the data integrity, the operating condition stability, and the compensation effectiveness. Based on the diagnostic confidence level and the insulation status diagnostic result, a diagnostic output result is determined; wherein, when the diagnostic confidence level is lower than a preset confidence threshold, the diagnostic output result includes a retest prompt.

[0012] This specification provides a high-voltage DC bushing dielectric response diagnostic device, comprising: The data acquisition module is used to acquire the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data and preset reference conditions of the target high voltage DC bushing. The descriptive quantity determination module is used to determine the internal temperature gradient descriptive quantity of the target high voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data. The response data determination module is used to compensate the measured dielectric response data based on the internal temperature gradient description, the operating condition data, and the preset reference condition, and to determine the target dielectric response data under the preset reference condition. The result determination module is used to determine the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data.

[0013] This specification also provides an electronic device, including a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements a high-voltage DC bushing dielectric response diagnostic method.

[0014] This specification also provides a computer-readable storage medium storing computer instructions that, when executed, implement a method for diagnosing the dielectric response of a high-voltage DC bushing. The method involves acquiring measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and a preset reference condition of the target high-voltage DC bushing; determining an internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data; compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition; and determining the insulation state diagnosis result of the target high-voltage DC bushing based on the target dielectric response data. In this way, the temperature of multiple internal regions and the internal temperature gradient descriptor of the high-voltage DC bushing are determined based on the multi-point temperature data of the outer surface and the operating condition data, and the measured dielectric response data is compensated using the internal temperature gradient descriptor, the operating condition data, and the preset reference condition. Therefore, it is possible to characterize the non-uniform temperature distribution in the axial, radial and local areas inside the bushing, reduce the influence of current carrying current, ambient temperature, wind speed and heat dissipation boundary changes on dielectric response data, improve the comparability of dielectric response data under different operating conditions, and thus improve the accuracy and reliability of insulation condition diagnosis results. Attached Figure Description

[0015] To more clearly illustrate the embodiments of this specification, the accompanying drawings used in the embodiments will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic flowchart of a high-voltage DC bushing dielectric response diagnostic method provided in one embodiment of this specification; Figure 2 This is a schematic diagram of the electronic device structure provided in one embodiment of this specification; Figure 3 This is a schematic diagram of the structural composition of a high-voltage DC bushing dielectric response diagnostic device provided in one embodiment of this specification; Figure 4 This is a schematic diagram of the overall process of another high-voltage DC bushing dielectric response diagnosis method provided in one embodiment of this specification; Figure 5 This is a schematic diagram of a dielectric response joint compensation model provided in one embodiment of this specification; Figure 6 This is a schematic diagram of frequency band compensation and frequency point-by-frequency dynamic compensation provided in one embodiment of this specification. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0018] See Figure 1 As shown in the embodiments of this specification, a method for diagnosing the dielectric response of a high-voltage DC bushing is provided, specifically applied to the server side. In practical implementation, the method may include the following: S101: Acquire the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data and preset reference conditions of the target high voltage DC bushing; S102: Determine the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data; S103: Based on the internal temperature gradient description, the operating condition data, and the preset reference condition, the measured dielectric response data is compensated to determine the target dielectric response data under the preset reference condition. S104: Determine the insulation status diagnosis result of the target high voltage DC bushing based on the target dielectric response data.

[0019] The aforementioned target high-voltage DC bushing can refer to the high-voltage DC bushing used as the object of dielectric response diagnosis. It can be the bushing of converter transformer, smoothing reactor, or valve hall through-wall bushing, or it can be a high-voltage DC insulating component with temperature distribution differences during operation, such as oil-paper insulating bushing, resin-impregnated paper bushing, or composite insulating bushing.

[0020] The aforementioned measured dielectric response data refers to the dielectric response data collected through the bushing end screen measurement terminal, test tap, or equivalent measurement terminal under the current operating condition of the target high-voltage DC bushing. The measured dielectric response data may include one or more of the following parameters corresponding to multiple test frequencies: complex capacitance, dielectric loss factor, complex dielectric constant, and dielectric modulus, used to characterize the dielectric properties of the target high-voltage DC bushing under the current operating conditions.

[0021] The aforementioned multi-point temperature data on the outer surface refers to temperature data collected at multiple locations on the outer surface of the target high-voltage DC bushing. These multiple temperature collection locations can be distributed along the axial direction of the target high-voltage DC bushing and cover multiple areas within the main insulation region, the flange adjacent region, and the end connection region, to reflect the temperature distribution on the outer surface of the target high-voltage DC bushing.

[0022] The aforementioned operating condition data refers to data that characterizes the operating status and external environmental conditions of the target high-voltage DC bushing during the test period corresponding to the measured dielectric response data. The operating condition data may include current-carrying current and environmental boundary data, which may include at least ambient temperature and wind speed, and may also include ambient relative humidity.

[0023] The aforementioned preset reference operating condition refers to a target operating condition that is pre-set and used to uniformly convert dielectric response data under different operating conditions. The preset reference operating condition may include reference temperature, reference current carrying capacity, and reference environmental boundary conditions, and can be set according to standard operating conditions, health benchmark operating conditions of the same type of bushing, historical stable operating conditions, or operation and maintenance requirements.

[0024] The aforementioned internal temperature gradient descriptor can refer to a state quantity determined based on the multi-point temperature data of the outer surface and the operating condition data, used to characterize the non-uniform temperature distribution inside the target high-voltage DC bushing. The internal temperature gradient descriptor may include one or more of equivalent average temperature, axial temperature difference, and radial temperature difference, and may also include the temperature difference between the flange area and the main body area and a hot spot correction factor, used to characterize the temperature differences between different internal regions.

[0025] The aforementioned target dielectric response data can refer to the equivalent dielectric response data corresponding to the preset reference condition, obtained after compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition. The target dielectric response data is used to reduce the impact of the difference between the current operating condition and the preset reference condition on the dielectric response, enabling comparison of dielectric response data obtained under different operating conditions under a unified operating condition.

[0026] The aforementioned insulation condition diagnostic results can refer to the diagnostic results determined based on the target dielectric response data, used to characterize the insulation condition of the target high-voltage DC bushing. The insulation condition diagnostic results can be represented by status labels, status levels, or status indicators, and may include one or more of the following: normal status, status of concern, damp status, aging status, and abnormal insulation status.

[0027] In some embodiments, acquiring the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference operating conditions of the target high-voltage DC bushing may specifically include the following: The dielectric response quantities corresponding to multiple test frequencies are obtained through the end screen measurement terminal or test tap of the target high voltage DC bushing, and the measured dielectric response data are determined according to each test frequency and its corresponding dielectric response quantity. The temperature values ​​corresponding to multiple temperature measurement positions on the outer surface of the target high voltage DC bushing are obtained, and the multi-point temperature data of the outer surface are determined based on each temperature measurement position and its corresponding temperature value. The current-carrying current of the target high-voltage DC bushing, as well as the ambient temperature and wind speed of the environment where the target high-voltage DC bushing is located, are obtained, and the operating condition data are determined based on the current-carrying current, the ambient temperature, and the wind speed. Obtain reference temperature, reference current carrying capacity and reference environmental boundary conditions, and determine the preset reference operating condition based on the reference temperature, the reference current carrying capacity and the reference environmental boundary conditions; The dielectric response quantity includes at least one of complex capacitance, dielectric loss factor, complex dielectric constant, and dielectric modulus.

[0028] By acquiring dielectric response quantities corresponding to multiple test frequencies, temperature values, current-carrying currents, ambient temperature, and wind speeds at multiple temperature measurement locations, and determining preset reference operating conditions based on reference temperature, reference current-carrying current, and reference environmental boundary conditions, a complete data foundation can be provided for determining internal temperature gradient descriptors and compensating for measured dielectric response data. This ensures that dielectric response data corresponds to operating condition data, thereby improving the reliability of target dielectric response data and the accuracy of insulation condition diagnosis results.

[0029] In some embodiments, firstly, the complex capacitance, dielectric loss factor, complex dielectric constant, or dielectric modulus corresponding to multiple test frequencies are collected through the end-screen measurement terminal of the target high-voltage DC bushing to determine the measured dielectric response data. Simultaneously, multiple temperature measurement points are arranged in the main insulation area, flange adjacent area, and end connection area of ​​the target high-voltage DC bushing to obtain multi-point temperature data on the outer surface, and the current-carrying current, ambient temperature, and wind speed during the test period are acquired to determine the operating condition data. Subsequently, using a preset segmented thermal network model, based on the multi-point temperature data on the outer surface and the operating condition data, the temperatures of the conductor adjacent layer, intermediate insulation layer, flange adjacent area, and end connection area are estimated, and internal temperature gradient descriptors, including equivalent average temperature, axial temperature difference, and radial temperature difference, are determined based on the temperature of each area. Furthermore, based on the internal temperature gradient description, the operating condition data, and the preset reference operating condition including reference temperature, reference current carrying current, and reference environmental boundary conditions, the measured dielectric response data is compensated to obtain the target dielectric response data under the preset reference operating condition; finally, based on the difference between the target dielectric response data and the healthy reference dielectric response data, the insulation status diagnosis result of the target high-voltage DC bushing is determined.

[0030] In some embodiments, the operating condition data includes current-carrying current and environmental boundary data. The method for determining the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data may further include the following: S1: Using a pre-defined segmented thermal network model, the initial temperature of multiple internal regions of the target high-voltage DC bushing is determined based on the current-carrying current and the environmental boundary data. S2: Based on the multi-point temperature data of the outer surface, the initial temperature corresponding to the multiple internal regions is corrected to determine the temperature of the multiple internal regions; S3: Determine the internal temperature gradient descriptor based on the temperatures of the multiple internal regions.

[0031] In specific implementation, the target high-voltage DC bushing is divided axially into an upper lead-out area, an upper insulation area, a flange adjacent area, a lower insulation area, and a lower connection area, and radially into a conductor adjacent layer, an intermediate insulation layer, and an outer layer. The intersection of each axial region and each radial layer is used as a thermal network node. Axial thermal resistance and radial thermal resistance are set according to the heat transfer path between adjacent thermal network nodes. Local equivalent thermal resistance and contact thermal resistance are set according to the heat dissipation characteristics of the flange adjacent area and the end connection area. The node heat capacity is set according to the heat storage capacity of the material corresponding to each thermal network node, thereby forming the preset segmented thermal network model.

[0032] The Joule heat of the conductor is determined based on the current-carrying current, and this Joule heat is used as the main heat source of the preset segmented thermal network model. The heat transfer boundaries of each outer surface node are determined based on the environmental boundary data, which includes at least ambient temperature and wind speed. The ambient temperature is used to determine the external reference temperature, and the wind speed is used to determine the convective heat transfer conditions on the outer surface. The Joule heat of the conductor and the heat transfer boundaries are input into the preset segmented thermal network model. Based on the thermal resistance relationship between each thermal network node and the node heat capacity, the initial temperatures corresponding to multiple internal regions are determined. These multiple internal regions include at least the conductor adjacent layer, the intermediate insulation layer, the flange adjacent region, and the end connection region.

[0033] Multiple temperature measurement positions are axially arranged on the outer surface of the target high-voltage DC bushing, covering at least the main insulation area, the flange adjacent area, and the end connection area. Based on the correspondence between each temperature measurement position and the outer surface node in the preset segmented thermal network model, the measured temperature at each measurement position is compared with the initial temperature of the corresponding outer surface node to determine the temperature estimation deviation for each outer surface node. Based on the temperature estimation deviation, the temperatures of internal nodes with heat transfer relationships to each outer surface node are corrected to determine the temperatures of multiple internal regions. When there are local temperature abrupt changes in the flange adjacent area or end connection area, the outer surface temperature data of the corresponding region is used to independently correct the internal node temperature of that region to reduce the impact of differences in local heat dissipation conditions on the internal temperature estimation results.

[0034] Based on the temperatures of the multiple internal regions, the equivalent average temperature of the target high-voltage DC bushing is determined; the axial temperature difference is determined based on the temperature differences between the internal regions corresponding to different axial regions; the radial temperature difference is determined based on the temperature differences between the internal regions corresponding to different radial layers within the same axial region; the temperature difference between the flange area and the main body insulation area can also be determined based on the temperature difference between the flange adjacent area and the main body insulation area, and a hot spot correction factor is determined based on the relationship between the highest temperature among the multiple internal region temperatures and the equivalent average temperature. The internal temperature gradient descriptor is determined based on the equivalent average temperature, the axial temperature difference, and the radial temperature difference, or further combined with the temperature difference between the flange area and the main body area and the hot spot correction factor.

[0035] When there are continuous missing temperatures at multiple points on the outer surface, when the change in the current-carrying current or environmental boundary data exceeds the corresponding valid upper limit of the data, or when the deviation between the corrected outer surface node temperature and the corresponding measured temperature exceeds a preset deviation threshold, the internal temperature gradient descriptor is marked as low confidence, and the use of the low confidence internal temperature gradient descriptor for deterministic dielectric response compensation is stopped, in order to avoid erroneous compensation caused by abnormal measurement data or model mismatch.

[0036] By segmenting the target high-voltage DC bushing axially and layering it radially, and combining the heat source formed by the current-carrying current, the heat dissipation boundary formed by environmental boundary data, and the temperature data of multiple points on the outer surface to correct the internal temperature estimation results, it is possible to obtain the temperature of multiple internal regions that reflect the actual non-uniform temperature distribution inside the bushing. This allows for the accurate determination of internal temperature gradient descriptors such as axial temperature difference and radial temperature difference, providing a reliable basis for operating condition compensation of measured dielectric response data and improving the comparability of dielectric response data under different operating conditions.

[0037] In some embodiments, the plurality of internal regions include a plurality of axial regions distributed along the axis of the target high-voltage DC bushing and a plurality of radial regions distributed along the radial direction of the target high-voltage DC bushing. The method for determining the internal temperature gradient descriptor based on the temperature of the plurality of internal regions may further include the following in specific implementations: S1: Determine the axial temperature difference based on the temperatures corresponding to the multiple axial regions; S2: Determine the radial temperature difference based on the temperatures corresponding to the multiple radial regions; S3: Determine the equivalent average temperature based on the temperatures of the multiple internal regions; S4: Determine the internal temperature gradient descriptor based on the axial temperature difference, the radial temperature difference, and the equivalent average temperature.

[0038] In specific implementation, the target high-voltage DC bushing is divided axially into an upper lead-out area, an upper insulation area, a flange adjacent area, a lower insulation area, and a lower connection area, and radially into a conductor adjacent layer, an intermediate insulation layer, and an outer layer. Based on the axial position of each internal region, the temperatures of internal regions belonging to the same axial region are aggregated and weighted according to the volume, node heat capacity, or preset region weight to determine the axial representative temperature of each axial region. Similarly, based on the radial hierarchy of each internal region, the temperatures of internal regions belonging to the same radial region are aggregated and weighted according to the volume, node heat capacity, or preset region weight to determine the radial representative temperature of each radial region.

[0039] Based on the representative axial temperatures corresponding to each axial region, the highest and lowest axial temperatures are determined, and the difference between the highest and lowest axial temperatures is defined as the axial temperature difference. In another embodiment, the temperature differences between the upper lead-out area and the flange adjacent area, and between the flange adjacent area and the lower connection area, can also be calculated separately, and the axial temperature difference is determined based on the maximum value among multiple temperature differences, to characterize the non-uniform axial temperature distribution formed by the combined effects of flange heat dissipation, end connection heat dissipation, and conductor heating.

[0040] Based on the radial representative temperature corresponding to each radial region, the temperature difference between the conductor's adjacent layer and the outer surface layer is determined, and this temperature difference is defined as the radial temperature difference. When the target high-voltage DC bushing includes multiple axial positions, the temperature difference between the conductor's adjacent layer and the outer surface layer at each axial position is determined, and the radial temperature difference is determined based on the maximum value or weighted average of the multiple temperature differences. Thus, the radial temperature difference can characterize the radial temperature attenuation that occurs during the heat transfer from the current-carrying conductor to the outer surface of the bushing.

[0041] An equivalent average temperature is determined based on the temperatures of multiple internal regions and their corresponding region weights. The region weights can be determined according to the volume of each internal region, the proportion of insulation material, or the heat capacity of a node, and each region weight is normalized. The temperature of each internal region is multiplied by its corresponding normalized region weight, and the results are summed to determine the equivalent average temperature. Compared to directly using the temperature at a single measurement location or the arithmetic mean of multiple temperatures, this equivalent average temperature can reduce the impact of differences in region size and heat storage capacity on the overall temperature characterization results.

[0042] The axial temperature difference, the radial temperature difference, and the equivalent average temperature are combined in a preset order to determine the internal temperature gradient descriptor. The equivalent average temperature in the internal temperature gradient descriptor characterizes the overall thermal state of the target high-voltage DC bushing, the axial temperature difference characterizes the temperature difference between different axial regions, and the radial temperature difference characterizes the temperature difference between different radial layers. The internal temperature gradient descriptor serves as a state variable for compensating for measured dielectric response data, used to determine the degree of deviation of the current internal temperature distribution from a preset reference condition.

[0043] By performing axial aggregation, radial aggregation, and weighted processing on the temperatures of multiple internal regions, the non-uniform temperature distribution inside the target high-voltage DC bushing can be characterized from three aspects: overall temperature level, axial temperature difference, and radial temperature difference. This avoids the insufficient temperature state characterization caused by using only single-point temperature or average temperature, and provides more accurate state variables for the reference condition compensation of measured dielectric response data, thereby improving the comparability of dielectric response data under different operating conditions and the accuracy of insulation state diagnosis results.

[0044] In some embodiments, the method of compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition to determine the target dielectric response data under the preset reference operating condition may further include the following: S1: Based on the test frequency corresponding to the measured dielectric response data, the measured dielectric response data is divided into multiple frequency band dielectric response data. S2: For each band dielectric response data, determine the compensation parameters corresponding to the band dielectric response data based on the internal temperature gradient description, the operating condition data, and the preset reference condition. S3: Using the compensation parameters corresponding to each frequency band dielectric response data, compensate for each frequency band dielectric response data to determine multiple compensated dielectric response data; S4: Determine the target dielectric response data based on the plurality of compensated dielectric response data.

[0045] In practice, based on the test frequencies corresponding to each dielectric response quantity in the measured dielectric response data, the test frequency range is divided into low-frequency, mid-frequency, and high-frequency bands. Furthermore, based on the band to which each test frequency belongs, the measured dielectric response data is divided into low-frequency band dielectric response data, mid-frequency band dielectric response data, and high-frequency band dielectric response data. The low-frequency band dielectric response data is used to characterize conductivity loss and slow polarization processes; the mid-frequency band dielectric response data is used to characterize interface polarization and relaxation processes; and the high-frequency band dielectric response data is used to characterize rapid polarization and geometric capacitance characteristics. The frequency boundaries of each band can be predetermined based on the insulation material type of the target high-voltage DC bushing, the dielectric response test range, and the dielectric response curve under healthy conditions.

[0046] For any frequency band dielectric response data, the temperature deviation of the target HVDC bushing's current internal temperature distribution relative to the preset reference operating condition is determined based on the internal temperature gradient descriptor. The operating condition deviations of the current current-carrying current and current environmental boundary conditions relative to the preset reference operating condition are determined based on the operating condition data. Compensation parameters corresponding to the dielectric response data of that frequency band are then determined based on the temperature deviation and the operating condition deviation. The compensation parameters include a frequency correction factor and an amplitude correction factor, and may also include an offset correction. The frequency correction factor is used to correct the positional change of the dielectric response characteristic on the frequency axis, the amplitude correction factor is used to correct the amplitude change of the dielectric response quantity, and the offset correction is used to correct the residual response deviation caused by the current operating condition.

[0047] The compensation parameters for each frequency band can be predetermined based on the dielectric response data obtained from the healthy high-voltage DC bushing under multiple calibration conditions. Specifically, the internal temperature gradient descriptor, operating condition data, and dielectric response data under each calibration condition are compared with the dielectric response data under the preset reference condition to determine the frequency offset and amplitude variation of the dielectric response characteristics in different frequency bands, and to establish the correspondence between the internal temperature gradient descriptor, the operating condition data, the preset reference condition, and each compensation parameter. The compensation parameters are determined using only calibration data with normal insulation condition, stable operating condition, and complete data; data with moisture, aging, insulation abnormalities, or low confidence are not used to avoid compensating for changes in insulation condition as an influence of operating condition.

[0048] Using compensation parameters corresponding to the low-frequency band, frequency and amplitude corrections are performed on the low-frequency band dielectric response data to determine the low-frequency band compensated dielectric response data. Similarly, using compensation parameters corresponding to the mid-frequency band, frequency and amplitude corrections are performed on the mid-frequency band dielectric response data to determine the mid-frequency band compensated dielectric response data. Likewise, using compensation parameters corresponding to the high-frequency band, frequency and amplitude corrections are performed on the high-frequency band dielectric response data to determine the high-frequency band compensated dielectric response data. When the compensation parameters for any frequency band include an offset correction, after completing the frequency and amplitude corrections, the offset correction is used to perform an offset correction on the dielectric response of the corresponding frequency band.

[0049] When the target frequency after frequency correction lies between two adjacent measured frequencies, interpolation is performed based on the dielectric response values ​​corresponding to the two adjacent measured frequencies to determine the compensated dielectric response value corresponding to the target frequency. When the target frequency exceeds the test frequency range of the measured dielectric response data, no extrapolation is performed, and the compensation result for the corresponding frequency band is marked as low confidence. A preset parameter range is set for each compensation parameter. When a compensation parameter exceeds the preset parameter range, the compensation parameter is limited to the preset parameter range, or the output of the deterministic compensation result for the corresponding frequency band is stopped, to avoid overcompensating the measured dielectric response data.

[0050] Based on the magnitude of each test frequency, the low-frequency band compensated dielectric response data, the mid-frequency band compensated dielectric response data, and the high-frequency band compensated dielectric response data are arranged and combined to determine the target dielectric response data covering the test frequency range. The target dielectric response data represents the equivalent dielectric response of the target high-voltage DC bushing under the preset reference operating conditions, and is used to subsequently determine the insulation status diagnosis result of the target high-voltage DC bushing.

[0051] By dividing the measured dielectric response data into multiple frequency bands according to the test frequency, and determining the frequency correction factor, amplitude correction factor, and bias correction amount for each frequency band, it can adapt to the differences in dielectric response mechanisms and their sensitivity to operating conditions in different frequency bands. This avoids the compensation deviation caused by using uniform compensation parameters to correct the entire dielectric response curve, thereby improving the accuracy and comparability of the target dielectric response data under preset reference operating conditions and improving the reliability of insulation condition diagnosis results.

[0052] In one embodiment, the operating condition data includes current-carrying current and environmental boundary data; when the current-carrying current, the environmental boundary data, and the multi-point temperature data of the outer surface are all within their respective preset effective ranges, and the acquisition duration of the measured dielectric response data is greater than a preset duration or the operating condition stability during the test is lower than a preset stability threshold, the step of compensating the measured dielectric response data according to the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition includes: S1: For each test frequency point in the measured dielectric response data, determine the frequency point temperature data and frequency point operating condition data corresponding to the test frequency point according to the test time period corresponding to the test frequency point; S2: Determine the frequency temperature gradient descriptor corresponding to the test frequency point based on the frequency point temperature data and the frequency point operating condition data; S3: Based on the frequency point temperature gradient description, the frequency point operating condition data, and the preset reference condition, determine the frequency point compensation parameter corresponding to the test frequency point, and use the frequency point compensation parameter to compensate the dielectric response corresponding to the test frequency point to determine the frequency point compensation dielectric response. S4: Determine the target dielectric response data based on the frequency point compensation dielectric response corresponding to each of the test frequency points.

[0053] In practice, the start and end times of each test frequency point in the measured dielectric response data are recorded, and the corresponding test time period for each test frequency point is determined based on the start and end times. When all data are within their respective preset valid ranges, and the total acquisition time of the measured dielectric response data exceeds the preset time, or any change in the current-carrying current, ambient temperature, wind speed, or external surface temperature during the acquisition period exceeds the corresponding preset stability threshold, a frequency-point compensation method is adopted to avoid using the operating data from different test periods as the compensation basis for the entire dielectric response curve. When any data exceeds the corresponding preset valid range, the corresponding data window is marked as low confidence and a retest is prompted.

[0054] For any given test frequency point, multiple temperature sampling values ​​within the corresponding test time period are extracted from the multi-point temperature data of the outer surface. The average, median, or weighted average of each temperature measurement location within the test time period is calculated to determine the frequency point temperature data corresponding to the test frequency point. Current carrying capacity, ambient temperature, and wind speed within the same test time period are extracted from the operating condition data. Based on the average, median, or weighted average of each operating parameter within the test time period, the frequency point operating condition data corresponding to the test frequency point is determined. If abnormal sampling values ​​exist within the test time period, these abnormal sampling values ​​are removed according to a preset physical range and statistical threshold. When the number of valid samples is lower than a preset number or the duration of continuous missing samples exceeds a preset missing threshold, the corresponding test frequency point is marked as a low-confidence frequency point.

[0055] Using a pre-defined segmented thermal network model, the temperatures of multiple internal regions corresponding to the test frequency point are determined based on the frequency point temperature data and the frequency point operating condition data. Specifically, the conductor heat source within the test time period is determined based on the current-carrying current in the frequency point operating condition data, the heat dissipation boundary within the test time period is determined based on the ambient temperature and the wind speed, and the temperature estimation results of multiple internal regions are corrected based on the frequency point temperature data; based on the corrected temperatures of multiple internal regions, the equivalent average temperature, axial temperature difference, and radial temperature difference corresponding to the test frequency point are determined, and the frequency point temperature gradient descriptor is determined based on the equivalent average temperature, the axial temperature difference, and the radial temperature difference.

[0056] Based on the frequency-point temperature gradient descriptor, the temperature deviation of the internal temperature state corresponding to the test frequency point relative to the preset reference operating condition is determined; based on the frequency-point operating condition data, the operating condition deviation of the current-carrying current and environmental boundary corresponding to the test frequency point relative to the preset reference operating condition is determined; based on the temperature deviation and the operating condition deviation, the frequency correction factor and amplitude correction factor corresponding to the test frequency point are determined, and the bias correction amount can be further determined. The target frequency corresponding to the test frequency point is corrected using the frequency correction factor, and the dielectric response corresponding to the test frequency point is corrected using the amplitude correction factor and the bias correction amount, thus determining the frequency-point compensated dielectric response amount.

[0057] When the corrected target frequency is located between adjacent measured frequency points, interpolation is performed based on the dielectric response corresponding to the adjacent measured frequency points to determine the frequency-point compensation dielectric response corresponding to the target frequency. When the target frequency exceeds the test frequency range of the measured dielectric response data, frequency range extrapolation is not performed, and the confidence level of the corresponding frequency-point compensation dielectric response is reduced. Allowable ranges are set for the frequency correction factor, the amplitude correction factor, and the bias correction amount. When any compensation parameter exceeds the corresponding allowable range, the compensation parameter is amplitude-limited or the corresponding test frequency point is marked as a low-confidence frequency point to avoid over-compensation of the dielectric response.

[0058] Based on the corrected target frequency corresponding to each test frequency point, the compensated dielectric response quantities of each frequency point are sorted and combined to determine the target dielectric response data under the preset reference operating condition. For low-confidence frequency points, the corresponding confidence level can be retained, or a prompt can be made to supplement the test frequency point, without directly outputting the deterministic insulation state diagnosis result using low-confidence frequency points.

[0059] By assigning each test frequency point to multiple temperature data points on the outer surface and operating condition data within its actual test time period, and independently compensating based on the corresponding frequency temperature gradient descriptor, the differences in operating conditions between frequency points caused by changes in current carrying capacity, environmental conditions, and internal temperature distribution when the dielectric response acquisition time is long can be reduced. This allows the combined target dielectric response data to more accurately correspond to the preset reference operating conditions, thereby improving the comparability of dielectric response data under different operating conditions and the reliability of insulation condition diagnosis results.

[0060] In some embodiments, the method for determining the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data may further include the following: S1: Obtain the preset health reference dielectric response data corresponding to the target high voltage DC bushing; S2: Determine the low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, and high-frequency dielectric response characteristics based on the target dielectric response data; S3: Determine the dielectric response residual characteristics based on the target dielectric response data and the preset healthy reference dielectric response data; S4: Determine the moisture state index, aging state index, and abnormal state index based on the low-frequency dielectric response characteristics, the mid-frequency dielectric response characteristics, the high-frequency dielectric response characteristics, and the dielectric response residual characteristics; S5: Determine the insulation condition diagnosis result based on the moisture condition index, the aging condition index, and the abnormal condition index.

[0061] In practice, a high-voltage DC bushing of the same model as the target high-voltage DC bushing, confirmed to be in a healthy state through maintenance or historical operating data, is selected. Under the preset reference operating conditions, dielectric response quantities corresponding to multiple test frequencies are acquired and arranged according to the test frequencies to determine the preset healthy reference dielectric response data. The preset healthy reference dielectric response data and the target dielectric response data use the same dielectric response quantity type and test frequency range to enable comparison between the two under the same reference operating conditions and the same frequency scale.

[0062] Based on the preset frequency ranges corresponding to low-frequency, mid-frequency, and high-frequency bands, the target dielectric response data is divided into low-frequency target dielectric response data, mid-frequency target dielectric response data, and high-frequency target dielectric response data. Based on the low-frequency target dielectric response data, at least one of the following is determined as the low-frequency dielectric loss, the slope of the low-frequency dielectric loss change, and the ratio of low-frequency to mid-frequency dielectric loss, as the low-frequency dielectric response characteristic. Based on the mid-frequency target dielectric response data, at least one of the following is determined as the mid-frequency dielectric response characteristic: the peak frequency of the imaginary part of the dielectric modulus, the peak value of the imaginary part of the dielectric modulus, the peak value of the imaginary part of the complex dielectric constant, and the mid-frequency relaxation characteristic. Based on the high-frequency target dielectric response data, at least one of the following is determined as the high-frequency dielectric response characteristic: the rate of change of complex capacitance and the high-frequency capacitance stability.

[0063] Based on each test frequency, the target dielectric response data and the preset healthy reference dielectric response data are frequency aligned. For test frequencies that do not directly correspond between the target dielectric response data and the preset healthy reference dielectric response data, interpolation is performed based on the dielectric response quantities corresponding to adjacent test frequencies to determine the dielectric response quantity at the same test frequency. Based on the difference between the target dielectric response data and the preset healthy reference dielectric response data at each test frequency and the preset weights corresponding to each test frequency, the dielectric response curve residual is determined, and the dielectric response curve residual is used as the dielectric response residual feature; wherein, different preset weights can be set for the low-frequency band, mid-frequency band, and high-frequency band according to the sensitivity of the corresponding dielectric response features to the insulation state.

[0064] Based on the characteristic statistical parameters corresponding to the health status samples, the low-frequency dielectric response characteristics, the mid-frequency dielectric response characteristics, the high-frequency dielectric response characteristics, and the dielectric response residual characteristics are normalized to determine the normalized dielectric response characteristics. The moisture-induced state index is determined based on the low-frequency dielectric loss and the relative change between low-frequency and mid-frequency dielectric losses in the normalized dielectric response characteristics. The aging state index is determined based on the mid-frequency relaxation characteristics and dielectric modulus characteristics in the normalized dielectric response characteristics. The abnormal state index is determined based on the dielectric response residual characteristics, high-frequency capacitance stability, and complex capacitance change rate in the normalized dielectric response characteristics. The moisture-induced state index, the aging state index, and the abnormal state index are first calculated numerically based on corresponding characteristics and preset weights. After numerical judgment, the numerical judgment results can be mapped to a level or status label.

[0065] Based on the statistical range of healthy bushings of the same model, confirmed abnormal samples, or calibration data, the normal range and abnormality criteria corresponding to the moisture state index, the aging state index, and the abnormal state index are determined respectively. When all three state indices are within their corresponding normal ranges, the insulation state diagnosis result is determined to be normal; when any state index reaches its corresponding abnormality criterion, the insulation state diagnosis result is determined to be abnormal; when any state index is between its corresponding normal range and the abnormality criterion, the insulation state diagnosis result is determined to be of concern. When the moisture state index reaches the abnormality criterion and the aging state index is within the normal range, it is determined to be a moisture-dominated abnormality; when the aging state index reaches the abnormality criterion and the moisture state index is within the normal range, it is determined to be an aging-dominated abnormality; when both the moisture state index and the aging state index reach their corresponding abnormality criteria, or when the abnormal state index reaches the abnormality criterion, it is determined to be a composite abnormality or other insulation abnormality.

[0066] By comparing the target dielectric response data with the healthy reference dielectric response data under preset reference operating conditions, and extracting low-frequency, medium-frequency, and high-frequency dielectric response characteristics and dielectric response residual characteristics respectively, the dielectric state of the target high-voltage DC bushing can be characterized from different frequency bands. In this way, the moisture state index, aging state index, and abnormal state index can be determined respectively, reducing the diagnostic bias caused by the mutual confusion of different insulation state characteristics and improving the accuracy and distinguishability of insulation state diagnosis results.

[0067] In some embodiments, the method may further include the following: S1: Determine the data integrity and operating condition stability based on the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data; S2: Compare the compensation parameters corresponding to each of the frequency band dielectric response data with the corresponding preset compensation parameter range, or compare the frequency point compensation parameters corresponding to each of the test frequency points with the corresponding preset compensation parameter range, and determine the compensation effectiveness based on the comparison results; S3: Determine the diagnostic confidence level based on the data integrity, the operating condition stability, and the compensation effectiveness; S4: Determine the diagnostic output result based on the diagnostic confidence level and the insulation status diagnostic result; wherein, when the diagnostic confidence level is lower than the preset confidence threshold, the diagnostic output result includes a retest prompt.

[0068] In practice, the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data are time-aligned based on the test time period corresponding to each test frequency point in the measured dielectric response data. For each test time period, the required sampling quantity, effective sampling quantity, missing quantity, and abnormal quantity of dielectric response quantity, temperature value at each temperature measurement location, current carrying current, and environmental boundary data are statistically analyzed. Data integrity is determined based on the relationship between the effective sampling quantity and the required sampling quantity. For short-term missing data, linear interpolation or fitting between adjacent temperature measurement locations can be used for repair. When the continuous missing duration exceeds a preset missing threshold, or the proportion of missing data or abnormal data exceeds the corresponding preset proportion threshold, the corresponding test time period is determined to be incomplete.

[0069] The stability of the operating condition is determined based on the changes in current-carrying current, external surface temperature, and environmental boundary data within each test period. Specifically, the current fluctuation is determined based on the maximum, minimum, or average value of the current-carrying current within the test period; the external surface temperature fluctuation is determined based on the temperature change at each temperature measurement location within the test period; and the environmental boundary fluctuation is determined based on the changes in ambient temperature and wind speed within the test period. When the current fluctuation, external surface temperature fluctuation, and environmental boundary fluctuation all do not exceed their respective preset stability thresholds, the test period is defined as a stable operating condition. When any fluctuation exceeds the stability threshold but does not exceed the upper limit of valid data, frequency-by-frequency compensation is used. When any fluctuation or data anomaly exceeds the upper limit of valid data, the corresponding data is marked as low confidence, and no definitive diagnostic conclusion is output.

[0070] For each frequency band dielectric response data, the corresponding frequency correction factor, amplitude correction factor, and offset correction amount are compared with the corresponding preset compensation parameter ranges. For each test frequency point, the corresponding frequency point correction factor, frequency point amplitude correction factor, and frequency point offset correction amount are compared with the corresponding preset compensation parameter ranges. When all compensation parameters are within the corresponding preset compensation parameter ranges, and the corrected frequency is within the test frequency range of the measured dielectric response data, the compensation for the corresponding frequency band or test frequency point is determined to be effective. When any compensation parameter exceeds the corresponding preset compensation parameter range, the compensation parameter is amplitude-limited, and the corresponding frequency band or test frequency point is determined to be low-effectiveness compensation. When the corrected frequency exceeds the test frequency range, or the compensation parameter continuously reaches the boundary of the preset compensation parameter range, the compensation for the corresponding frequency band or test frequency point is determined to be invalid, and the dielectric response amount exceeding the test frequency range is not extrapolated.

[0071] The diagnostic confidence level is determined based on the data integrity, operating condition stability, and compensation effectiveness. Specifically, evaluation values ​​can be set for data integrity, operating condition stability, and compensation effectiveness, and each evaluation value can be weighted according to its corresponding preset weight to determine the diagnostic confidence level. Alternatively, a judgment can be made according to preset confidence rules. When the data is incomplete, the operating condition fluctuation exceeds the upper limit of the valid data corresponding to the frequency-point compensation, the internal temperature determination result is invalid, or the compensation of at least one frequency band or test frequency point is invalid, the diagnostic confidence level is reduced. When the operating condition stability is lower than the preset stability threshold, but all data are still within the corresponding preset valid range and the frequency-point compensation is effective, the diagnostic confidence level is determined based on the frequency-point compensation result, and the diagnostic result is not directly judged as low confidence simply because the frequency-point compensation method is used.

[0072] The diagnostic output is determined based on the diagnostic confidence level and the insulation condition diagnostic result. When the diagnostic confidence level is not lower than a preset confidence threshold, the insulation condition diagnostic result and the corresponding diagnostic confidence level are output; when the diagnostic confidence level is lower than the preset confidence threshold, the insulation condition diagnostic result is not taken as a definitive diagnostic conclusion, and a low confidence marker and retest prompt are output. The retest prompt may include extending the dielectric response data acquisition time, reacquiring missing data, retesting after the operating conditions have stabilized, or recalibrating the parameters used for temperature inversion and dielectric response compensation.

[0073] By jointly evaluating the completeness of the collected data, the fluctuations in operating conditions during the test, and the effective range of the compensation parameters, it is possible to identify the adverse effects of missing data, changes in operating conditions, or abnormal compensation parameters on the insulation condition diagnosis results. When the diagnostic confidence is insufficient, a retest prompt will be output to avoid misjudging measurement abnormalities or compensation failures as insulation condition abnormalities, thereby improving the reliability of the diagnostic output results.

[0074] In some embodiments, this specification proposes a method for diagnosing the dielectric response of high-voltage DC bushings based on joint compensation of operating temperature gradient and boundary conditions. This method is particularly applicable to the operational status diagnosis of high-voltage DC through-wall bushings, converter station DC bushings, and oil-paper insulated bushings, resin-impregnated paper bushings, or composite insulated bushings with significant temperature distribution differences.

[0075] During operation, the target high-voltage DC bushing is affected by factors such as Joule heating of the current-carrying conductor, dielectric loss heat, flange heat dissipation, end connection structure heat dissipation, ambient temperature, wind speed, and load fluctuations. Consequently, significant axial and radial temperature gradients typically exist inside the target high-voltage DC bushing. Measured dielectric response data is sensitive to temperature and operating conditions. Directly using measured dielectric response data to determine moisture or aging can easily misinterpret changes in operating conditions as insulation degradation.

[0076] To address the aforementioned issues, this invention employs a continuous technical chain of "measurable external surface parameters—internal temperature gradient—dielectric response compensation—condition diagnosis": it simultaneously acquires measured dielectric response data, multi-point external surface temperature data, and operating condition data; without directly deploying internal temperature sensors, it determines multiple internal region temperatures and internal temperature gradient descriptors based on the multi-point external surface temperature data and the operating condition data; then, based on the internal temperature gradient descriptors, the operating condition data, and a preset reference condition, it performs frequency band or frequency point-by-frequency compensation on the measured dielectric response data to determine the target dielectric response data under the preset reference condition.

[0077] Wideband dielectric spectrum acquisition, data preprocessing, thermal network solution, filtering estimation, feature extraction, weighted diagnosis, and trend warning all revolve around the above-mentioned technical chain. Among them, the key difference between this method and conventional temperature correction and conventional dielectric spectrum diagnosis is that "internal temperature gradient descriptors and operating condition data jointly participate in the compensation of measured dielectric response data".

[0078] The core of this specification lies in: determining the internal temperature gradient descriptor corresponding to the non-uniform temperature distribution inside the target high-voltage DC bushing based on multi-point temperature data of the outer surface and operating condition data; and, based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition, performing frequency band or frequency point-by-frequency compensation on the measured dielectric response data to determine the target dielectric response data under the preset reference condition, and determining the insulation status diagnosis result based on the target dielectric response data. Individual broadband dielectric spectrum measurements, thermal network modeling, or moisture / aging diagnostic models do not constitute the complete core of this invention.

[0079] In some embodiments, the method may include the following: S1: Acquire measured dielectric response data, multi-point temperature data of the outer surface, and operating condition data.

[0080] In a preferred embodiment of this specification, the measured dielectric response data is obtained using a broadband dielectric spectrum method, and the preferred test frequency range is: .

[0081] Five to ten test points are set up for each ten octave band. The dielectric response measured includes one or more of the following:

[0082] in, Indicates a complex capacitor. Indicates the dielectric loss factor. Represents the complex permittivity. Indicates dielectric modulus. Indicates the test frequency.

[0083] When acquiring measured dielectric response data during operation, the broadband disturbance measurement unit can be connected via the end-screen measurement terminal, test tap, or equivalent capacitance coupling measurement terminal of the target high-voltage DC bushing. Live-line testing-related functions such as DC blocking coupling, current limiting protection, broadband current detection, voltage reference acquisition, and isolated communication are subordinate implementation methods to ensure measurement safety.

[0084] To ensure the safety of online live testing, the preset range is further limited by the upper limit of disturbance voltage, the upper limit of injection current, the threshold for change in end-screen current, the threshold for change in recharge capacity, and the upper limit of single injection duration. During online testing, if any of the following conditions are met, the test at the current test frequency point will be stopped and a safe exit prompt will be output:

[0085] in, This indicates the disturbance injection voltage. Indicates the disturbance injection current. This indicates the reference end-screen current before the test. This indicates the change in current at the end screen during the test. This indicates the reference capacitance before testing. This indicates the change in complex capacitance during the test. The current-limiting protection module cuts off the disturbance channel when the threshold is exceeded; the opto-isolation communication module ensures electrical isolation between the diagnostic device and the station control equipment and measurement front end. Considering the long testing time for low-frequency dielectric response, a full-spectrum diagnostic mode and a fast online diagnostic mode can be set; this part serves as a subordinate selection for the method of acquiring measured dielectric response data.

[0086] Simultaneously acquired with the measured dielectric response data are multi-point temperature data of the outer surface and operating condition data. The operating condition data includes at least current carrying capacity, ambient temperature, and wind speed, and may further include ambient relative humidity. The multi-point temperature data of the outer surface and the operating condition data serve as the basic inputs for determining the internal temperature gradient descriptors and compensating for the measured dielectric response data.

[0087] S2: Data preprocessing and operational stability assessment.

[0088] The data window for diagnostics should complete time alignment, outlier removal, and necessary missing value repair to ensure that the test frequency points in the measured dielectric response data match the multi-point temperature data of the outer surface and operating condition data within the corresponding test time period. For a given test frequency point... If its corresponding test period is Then, the frequency point temperature data and frequency point operating condition data corresponding to the test frequency point can be taken as the average, median or weighted average of the corresponding data within the test time period.

[0089] The operating condition stability assessment is used to select the compensation method and evaluate the diagnostic confidence level. When the fluctuation of current carrying capacity, external surface temperature, or environmental boundary exceeds the stability threshold corresponding to the frequency band compensation, but the data is still within the preset valid range, frequency-by-frequency compensation is used. When the data missing rate, outlier ratio, parameter out-of-bounds degree, or model residual exceeds the corresponding data validity limit, the corresponding data window is marked as low confidence and is not used to output a deterministic diagnostic conclusion. Therefore, slight changes in operating conditions trigger frequency-by-frequency compensation, while severe data anomalies trigger low confidence processing; the two have different judgment levels.

[0090] S3: Set preset reference operating conditions.

[0091] To ensure the comparability of measured dielectric response data obtained under different operating conditions, this invention pre-sets a reference operating condition. This reference operating condition includes at least a reference temperature, a reference current-carrying current, and reference environmental boundary conditions. The preset reference operating condition can be expressed as:

[0092] in, This represents the preset reference working condition vector. Indicates reference temperature. Indicates the reference current. This indicates the reference environment boundary conditions.

[0093] The reference environmental boundary conditions can be expressed as:

[0094] in, Indicates the reference ambient temperature. Indicates reference relative humidity. This indicates the reference wind speed.

[0095] S4: Determine the internal temperature gradient descriptor based on multi-point temperature data of the outer surface and operating condition data.

[0096] This step is one of the core steps of this invention. This invention uses multi-point temperature data and operating condition data of the target high-voltage DC bushing's outer surface as input. Without directly deploying internal temperature sensors, it determines the temperature of multiple internal regions of the target high-voltage DC bushing and determines an internal temperature gradient descriptor based on these multiple internal region temperatures. These multiple internal regions may include areas such as the conductor adjacent layer, intermediate insulation layer, outer surface layer, flange adjacent area, and end connection area.

[0097] A pre-defined segmented thermal network model is used to describe the thermal behavior of the target HVDC bushing. Axially, the target HVDC bushing is divided into an upper lead-out area, an upper insulation area, a flange adjacent area, a lower insulation area, and a lower connection area. Radially, the target HVDC bushing is divided into a conductor adjacent layer, an intermediate insulation layer, and an outer surface layer. Thermal resistance characterizes the heat transfer path between discrete nodes, and thermal capacity characterizes the heat storage capacity. Conductor loss is considered the primary heat source, while dielectric loss heat and contact heat are considered auxiliary heat sources. Ambient temperature and wind speed in the operating data together constitute the outer surface convective heat transfer boundary.

[0098] Multiple temperature measurement positions for acquiring multi-point temperature data of the outer surface are arranged along the axial direction of the target high-voltage DC bushing, covering at least three or more of the following locations: the upper lead-out area, the middle of the main insulation, the flange adjacent area, and the lower connection area. Additional local temperature measurement positions may be added in the flange adjacent area and the end connection area to characterize abrupt changes in heat dissipation boundaries and contact thermal resistance. When a significant circumferential temperature difference exists, multiple circumferential temperature measurement positions can be arranged at the same axial position.

[0099] The continuous state equation of the pre-defined segmented heat network model can be expressed as:

[0100] in, Represents the discrete node temperature vector. Represents the heat capacity matrix. This represents the system matrix formed by the nodal thermal resistance relationships. Represents the model parameter vector. Represents the Joule heating term of a conductor. This represents the heat term for dielectric loss. Represents the boundary heat transfer term. This represents the noise term in the model.

[0101] The model parameter vector can be represented as:

[0102] in, Indicates axial thermal resistance; Indicates radial thermal resistance; Indicates the equivalent thermal resistance of the flange area; Indicates contact thermal resistance; This refers to the convective heat transfer coefficient parameter; This represents the heat capacity of the node. m This indicates the number of heat capacity parameters used.

[0103] The multi-point temperature data of the outer surface serves as the measured input for the internal temperature determination process. The pre-defined segmented thermal network model, based on the Joule heat generated by the current-carrying current, the dielectric loss heat, and the heat transfer boundaries formed by ambient temperature and wind speed in the operating condition data, combined with pre-determined axial thermal resistance, radial thermal resistance, equivalent thermal resistance of the flange area, contact thermal resistance, convective heat transfer parameters, and nodal heat capacity, determines the initial temperatures corresponding to multiple internal regions of the target high-voltage DC bushing. Based on the concurrently acquired multi-point temperature data of the outer surface, the initial temperatures corresponding to the multiple internal regions are corrected to determine the temperatures of the multiple internal regions.

[0104] The model parameters of the preset segmented thermal network model can be determined through health sleeve calibration tests, historical data confirmed to be normal after maintenance, or stable operating data. During online operation, the initial temperatures corresponding to the multiple internal regions are corrected based on the multi-point temperature data of the outer surface acquired concurrently. When measurement data is missing, operating conditions fluctuate excessively, model parameters exceed the preset physical range, or the deviation between the outer surface temperature corresponding to the temperatures of multiple internal regions and the multi-point temperature data of the outer surface exceeds a preset threshold, the current result is marked as low confidence, and recalibration or retesting is prompted. The relative humidity in the environmental boundary data serves as an auxiliary boundary quantity for the surface condition of the outer insulation, measurement disturbance risk, and compensation confidence, and is not directly used as the basis for judging the moisture status of the internal main insulation.

[0105] S5: Determine the internal temperature gradient descriptor based on the temperatures of multiple internal regions.

[0106] After obtaining the temperatures of the multiple internal regions, an internal temperature gradient descriptor for compensating the measured dielectric response data is determined based on these temperatures. This internal temperature gradient descriptor is not an independent temperature alarm indicator, but rather a state variable for compensating the measured dielectric response data, used to characterize the impact of the non-uniform internal temperature distribution on the dielectric response data of different frequency bands during operation.

[0107] in, This represents a quantity describing the internal temperature gradient. This indicates the equivalent average temperature of the bushing. Indicates axial temperature difference. Indicates radial temperature difference. This indicates the temperature difference between the flange area and the main body area. Indicates the hotspot correction factor. This indicates transpose.

[0108] The internal temperature gradient descriptor is an ordered state vector arranged in a preset order, including at least the equivalent average temperature, axial temperature difference, and radial temperature difference, and may further include the temperature difference between the flange area and the main body area and a hot spot correction factor. The internal temperature gradient descriptor used for model calibration has the same parameter order and dimension as the internal temperature gradient descriptor determined during online compensation.

[0109] The operating condition data includes current-carrying current and environmental boundary data; the environmental boundary data includes at least ambient temperature and wind speed, and may further include ambient relative humidity. The compensation state variables used for compensating the measured dielectric response data include the internal temperature gradient descriptor and the operating condition data.

[0110] The relative humidity of the environment is mainly used to characterize the surface condition of the outer insulation, the risk of disturbance in field measurement, and the compensation confidence level, and is not directly equivalent to the internal moisture state of the main insulation; the moisture state of the main insulation is judged based on the dielectric response characteristics corresponding to the target dielectric response data.

[0111] S6: Determine the target dielectric response data based on the internal temperature gradient descriptor, operating condition data, and preset reference conditions.

[0112] The key is to transform the internal temperature gradient descriptor into comparable dielectric response data. The compensation goal is not to perform average temperature correction or single shift on the entire measured dielectric response data, but rather to introduce the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition based on the differences in the response mechanisms of low-frequency, mid-frequency, and high-frequency frequencies, and to perform frequency-band compensation or frequency-point-by-frequency compensation on the measured dielectric response data.

[0113] Let the measured dielectric response under the current operating conditions be... The equivalent dielectric response after compensation under the reference operating condition is: ,in, Can represent , , or One of them. The current boundary condition vector is defined as: .

[0114] The overall compensation relationship can be expressed as: .

[0115] It should be noted that the current-carrying current I In S4, the conductor Joule heat source term participates in the determination of the multiple internal region temperatures and the internal temperature gradient descriptors; in this step, the current-carrying current... I Or its deviation is mainly used to characterize load disturbances, energized measurement coupling disturbances, or residual operating conditions not fully explained by the preset segmented thermal network model within the test window. If the temperature inversion residual is lower than the preset threshold and the load change has been described by the internal temperature gradient... G T If the current-carrying current is fully characterized, the coefficient of the current-carrying current term in the compensation model can be set to zero, thus avoiding the repeated inclusion of the influence of the current-carrying current.

[0116] Based on the test frequency corresponding to the measured dielectric response data, the measured dielectric response data is divided into low-frequency band dielectric response data, mid-frequency band dielectric response data, and high-frequency band dielectric response data: .

[0117] For any frequency band ,in The preferred expression for the compensation relationship is:

[0118] in, This represents the compensated dielectric response of frequency band b under the reference operating condition. Indicates frequency band b The measured dielectric response, This represents a positive frequency correction factor. Indicates the amplitude correction factor. This represents the bias correction amount with the same dimensions as R. This represents the compensated state variable, which is described by the temperature gradient. G T Current carrying capacity I Current boundary conditionsB and reference working conditions Together they determine the degree of deviation of the current test condition from the reference condition.

[0119] The compensation parameters corresponding to the dielectric response data of each frequency band are determined based on healthy bushings, historical samples confirmed to be normal after maintenance, or calibration test data under healthy operating conditions. Abnormal, concerning, or low-confidence samples are not used to update the compensation parameters to avoid eliminating real insulation defects as operating condition effects.

[0120] To prevent overcompensation, a preset compensation parameter range is set for each of the aforementioned compensation parameters. When a compensation parameter exceeds the preset compensation parameter range, the current operating condition exceeds the calibration sample range, or the compensation verification residual corresponding to a healthy calibration sample or cross-validation sample exceeds a preset verification threshold, the compensation effectiveness and diagnostic confidence are reduced, and a retest prompt is output. Abnormal results are not forcibly corrected to normal by further increasing the compensation amount.

[0121] When the corrected test frequency determined by the frequency correction factor is located between adjacent measured test frequency points, the dielectric response corresponding to the corrected test frequency can be obtained by interpolation; when the corrected test frequency exceeds the test frequency range of the measured dielectric response data, no extrapolation is performed, but the diagnostic confidence is reduced, test frequency points are supplemented, or compensation methods are switched.

[0122] When the current-carrying current, the environmental boundary data, and the multi-point temperature data of the outer surface are all within their respective preset effective ranges, and the acquisition duration of the measured dielectric response data is greater than the preset duration or the operating condition stability during the test is lower than the preset stability threshold, for each test frequency point in the measured dielectric response data, frequency point temperature data and frequency point operating condition data are determined according to the test time period corresponding to the test frequency point; frequency point temperature gradient descriptor is determined according to the frequency point temperature gradient descriptor, the frequency point operating condition data, and the preset reference condition; frequency point compensation parameters corresponding to the test frequency point are determined according to the frequency point compensation parameters, and the dielectric response corresponding to the test frequency point is compensated using the frequency point compensation parameters to determine the frequency point compensated dielectric response; and the target dielectric response data is determined according to the frequency point compensated dielectric response corresponding to each test frequency point.

[0123] S7: Determine the dielectric response characteristics based on the target dielectric response data.

[0124] After determining the internal temperature gradient descriptors for S4 to S6 and compensating for the measured dielectric response data, dielectric response characteristics for insulation condition diagnosis are determined based on the target dielectric response data under a unified preset reference operating condition scale.

[0125] The dielectric response characteristics may include one or more of the following: low-frequency dielectric loss and its variation trend, mid-frequency relaxation characteristics, high-frequency capacitance stability, broadband loss curve characteristics, complex capacitance variation characteristics, and dielectric response residual characteristics between the target dielectric response data and the preset healthy reference dielectric response data.

[0126] The dielectric response residual characteristic between the target dielectric response data and the preset healthy reference dielectric response data can be expressed as:

[0127] in, This indicates the difference between the two dielectric response curves. This indicates the dielectric response after compensation to the reference operating condition. This indicates the reference dielectric response of the same type of healthy bushing under reference operating conditions. This represents the weight corresponding to different frequency points.

[0128] Before determining the insulation state diagnosis result based on the dielectric response characteristics, the dielectric response characteristics can be normalized according to the statistical parameters of the healthy samples.

[0129] S8: Determine the insulation condition diagnosis result based on the dielectric response characteristics.

[0130] As a subordinate implementation, the insulation condition diagnosis result of the target high-voltage DC bushing can be determined based on the low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, high-frequency dielectric response characteristics, and dielectric response residual characteristics corresponding to the target dielectric response data. The insulation condition diagnosis result can be based on the moisture condition index. M Aging status indicators A and abnormal status indicators D Sure.

[0131] Among them, the moisture status index M The aging state index is mainly determined based on the relative changes between low-frequency dielectric loss, low-frequency dielectric response characteristics, and mid-frequency dielectric response characteristics; A The abnormal state index is mainly determined based on the mid-frequency relaxation characteristics and dielectric modulus characteristics; D It is mainly determined based on the dielectric response residual characteristics, high-frequency capacitance stability, and complex capacitance variation characteristics.

[0132] The moisture status index M The aging status indicators A and the abnormal state indicators DFirst, numerical calculations are performed. The normal range and abnormal criteria for each status indicator can be determined based on the statistical range of the same type of health cannula, confirmed abnormal samples, historical operating data, or test calibration results. After the numerical determination is completed, the numerical determination results can be mapped to a level or status label.

[0133] when M , A and D When all indicators are below their respective normal thresholds, the insulation condition diagnosis result is determined to be normal; when any indicator reaches or exceeds its abnormal threshold, the insulation condition diagnosis result is determined to be abnormal; all other cases are determined to be a state of concern. A retest prompt is only added when the diagnostic confidence level is below the preset confidence threshold to avoid confusing "state of concern" and "low confidence level" with the same judgment.

[0134] When updating the preset health reference dielectric response data or diagnostic benchmark online, only samples with stable operating conditions, complete data, high diagnostic confidence, and confirmed to be in a normal state are used to avoid abnormal samples affecting the preset health reference dielectric response data or diagnostic benchmark.

[0135] S9: Determine the diagnostic confidence level and diagnostic output results.

[0136] The diagnostic confidence level is determined comprehensively based on factors such as data integrity, operating condition stability, the deviation between the outer surface temperature corresponding to multiple internal regions and the temperature data at multiple points on the outer surface, and whether the compensation parameters corresponding to the dielectric response data of each frequency band are within the preset compensation parameter range.

[0137] When there is missing data, fluctuations in current-carrying current or environmental boundary data exceed the corresponding valid upper limit of data, internal temperature estimation deviation exceeds the preset threshold, compensation parameters frequently reach the boundary of the preset compensation parameter range, the current operating condition exceeds the calibration range of the compensation model, or the compensation verification residual exceeds the preset verification threshold, the diagnosis will be marked as low confidence.

[0138] The compensation verification residual refers to the difference between the compensation result and the measured dielectric response of the same sample under preset reference conditions, under health calibration or cross-validation conditions; the compensation verification residual is different from the dielectric response residual characteristic used for insulation condition diagnosis. .

[0139] The diagnostic output result is determined based on the diagnostic confidence level and the insulation status diagnostic result; when the diagnostic confidence level is lower than the preset confidence threshold, the diagnostic output result includes prompts to extend the test time, re-collect data, or perform a retest.

[0140] After obtaining multiple historical insulation condition diagnostic results, trend analysis can be performed on the dielectric response characteristics, moisture condition indicators, aging condition indicators, and abnormal condition indicators corresponding to the target dielectric response data. When the corresponding condition indicator has not yet reached the abnormality criterion, but continues to rise or its rate of change exceeds a preset range in multiple consecutive detection cycles, a trend warning is output in the diagnostic output results.

[0141] S10: High Voltage DC Bushing Dielectric Response Diagnostic System.

[0142] To implement the above method, this specification can also provide a high-voltage DC bushing dielectric response diagnostic system. The core functional units of the high-voltage DC bushing dielectric response diagnostic system include a temperature gradient determination unit, a dielectric response compensation unit, and an insulation condition diagnostic unit. Measured dielectric response data acquisition units, multi-point external surface temperature data acquisition units, operating condition data acquisition units, data preprocessing units, low confidence alert units, and trend warning units can be configured as subordinate functional units.

[0143] The temperature gradient determination unit is used to determine the temperature of multiple internal regions of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data, and to determine the internal temperature gradient descriptor based on the multiple internal region temperatures; the dielectric response compensation unit is used to perform frequency band compensation or frequency point compensation on the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data and the preset reference condition, and to determine the target dielectric response data under the preset reference condition; the insulation status diagnosis unit is used to determine the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data.

[0144] Based on the above embodiments, this technical solution compensates for the measured dielectric response data obtained under different load currents, ambient temperatures, wind speeds, and heat dissipation boundary conditions according to the internal temperature gradient descriptor, operating condition data, and preset reference conditions. It determines the target dielectric response data under the preset reference conditions, avoiding diagnostic bias caused by directly comparing the original dielectric response data under different operating conditions and improving the comparability of dielectric response results under different operating conditions. Simultaneously, by determining the internal temperature gradient descriptor based on multi-point temperature data of the outer surface and operating condition data, and using this internal temperature gradient descriptor for measured dielectric response data compensation, it can reflect the axial temperature difference, radial temperature difference, and local temperature differences inside the high-voltage DC bushing, reducing the risk of misjudging load changes, wind speed changes, or heat dissipation boundary changes as moisture, aging, or insulation abnormalities. Furthermore, this technical solution performs frequency band compensation on the measured dielectric response data according to the dielectric response characteristics corresponding to different test frequencies, and when the measured dielectric response data acquisition time is long, it further compensates for the frequency band differences. Compensation is performed at each test frequency point to reduce the impact of changes in current-carrying current, ambient temperature, and heat dissipation conditions on dielectric response data during testing, thereby improving the accuracy and stability of target dielectric response data and insulation condition diagnosis results. Based on this, low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, high-frequency dielectric response characteristics, and dielectric response residual characteristics are determined according to the target dielectric response data. Based on these, moisture condition indicators, aging condition indicators, and abnormal condition indicators are determined, which helps to distinguish between moisture, aging, and other insulation abnormal conditions, reducing confusion between changes in operating conditions and changes in insulation condition. Furthermore, this technical solution does not require direct installation of temperature sensors inside the high-voltage DC bushing. It can utilize multi-point temperature data from the outer surface, current-carrying current, and environmental boundary data to determine the internal temperature gradient descriptors and compensate for measured dielectric response data. It is applicable to high-voltage DC through-wall bushings, converter station DC bushings, and oil-paper insulating bushings, resin-impregnated paper bushings, and composite insulating bushings with significant internal temperature differences, demonstrating good engineering applicability.

[0145] Therefore, without directly deploying internal temperature sensors, this invention determines the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data. It then compensates the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition. This enables the comparability of dielectric response data under different operating conditions, and the insulation status diagnosis result is determined based on the target dielectric response data.

[0146] As can be seen from the above, the high-voltage DC bushing dielectric response diagnostic method provided in this specification acquires the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference operating condition of the target high-voltage DC bushing; determines the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data; compensates the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition to determine the target dielectric response data under the preset reference operating condition; and determines the insulation state diagnostic result of the target high-voltage DC bushing based on the target dielectric response data. In this way, by acquiring the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference operating conditions of the target high-voltage DC bushing, and determining the internal temperature gradient descriptor based on the multi-point temperature data of the outer surface and the operating condition data, the internal temperature difference of the target high-voltage DC bushing can be reflected. Furthermore, by compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating conditions, the comparability of dielectric response data under different operating conditions can be improved, thereby improving the accuracy of insulation condition diagnosis results.

[0147] See Figure 2 As shown in the embodiments of this specification, a specific electronic device is also provided, wherein the electronic device includes a network communication port 201, a processor 202 and a memory 203, and the above structures are connected by internal cables so that the various structures can perform specific data interaction.

[0148] Specifically, the network communication port 201 can be used to acquire the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference operating conditions of the target high-voltage DC bushing.

[0149] The processor 202 can be specifically used to determine the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data; to compensate the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data and the preset reference condition, and to determine the target dielectric response data under the preset reference condition; and to determine the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data.

[0150] The memory 203 can be used to store the corresponding instruction program.

[0151] Based on the above method, the relevant structural performance of electronic equipment can be effectively utilized to improve the data processing speed of electronic equipment and efficiently realize a high-voltage DC bushing dielectric response diagnosis method.

[0152] In this embodiment, the network communication port 201 can be a virtual port bound to different communication protocols, thereby enabling the sending or receiving of different data. For example, the network communication port can be a port responsible for web data communication, a port responsible for FTP data communication, or a port responsible for email data communication. Furthermore, the network communication port can also be a physical communication interface or communication chip. For example, it can be a wireless mobile network communication chip, such as GSM or CDMA; it can also be a Wi-Fi chip; or it can be a Bluetooth chip.

[0153] In this embodiment, the processor 202 can be implemented in any suitable manner. For example, the processor can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers, etc. This specification is not limiting.

[0154] In this embodiment, the memory 203 may include a hierarchy. In a digital system, anything that can store binary data can be a memory. In an integrated circuit, a circuit with storage function but no physical form is also called a memory, such as RAM, FIFO, etc. In a system, a storage device with a physical form is also called a memory, such as a memory stick, TF card, etc.

[0155] This specification also provides a computer-readable storage medium based on the above-described high-voltage DC bushing dielectric response diagnostic method. The method acquires measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and a preset reference condition of the target high-voltage DC bushing. Based on the multi-point temperature data of the outer surface and the operating condition data, it determines the internal temperature gradient descriptor of the target high-voltage DC bushing. Based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition, it compensates the measured dielectric response data to determine the target dielectric response data under the preset reference condition. Based on the target dielectric response data, it determines the insulation state diagnostic result of the target high-voltage DC bushing.

[0156] In this embodiment, the storage medium includes, but is not limited to, Random Access Memory (RAM), Read-Only Memory (ROM), Cache, Hard Disk Drive (HDD), or Memory Card. The memory can be used to store computer program instructions. The network communication unit can be an interface configured according to standards specified in the communication protocol for network connection communication.

[0157] In this embodiment, the specific functions and effects implemented by the program instructions stored in the computer-readable storage medium can be explained in comparison with other embodiments, and will not be repeated here.

[0158] See Figure 3 At the software level, this specification also provides a high-voltage DC bushing dielectric response diagnostic device, which may specifically include the following structural modules: The data acquisition module 301 is used to acquire the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data and preset reference conditions of the target high voltage DC bushing. The descriptive quantity determination module 302 is used to determine the internal temperature gradient descriptive quantity of the target high voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data. The response data determination module 303 is used to compensate the measured dielectric response data based on the internal temperature gradient description, the operating condition data and the preset reference condition, and determine the target dielectric response data under the preset reference condition. The result determination module 304 is used to determine the insulation status diagnosis result of the target high voltage DC bushing based on the target dielectric response data.

[0159] In some embodiments, the above-described descriptive quantity determination module 302, in specific implementation, utilizes a preset segmented thermal network model to determine the initial temperature corresponding to multiple internal regions of the target high-voltage DC bushing based on the current-carrying current and the environmental boundary data; corrects the initial temperature corresponding to the multiple internal regions based on the multi-point temperature data of the outer surface to determine the temperature of the multiple internal regions; the temperature gradient descriptive quantity determination module is used to determine the internal temperature gradient descriptive quantity based on the temperature of the multiple internal regions.

[0160] In some embodiments, the temperature gradient descriptor determination module, in specific implementation, determines the axial temperature difference based on the temperatures corresponding to the plurality of axial regions; determines the radial temperature difference based on the temperatures corresponding to the plurality of radial regions; determines the equivalent average temperature based on the temperatures of the plurality of internal regions; and determines the internal temperature gradient descriptor based on the axial temperature difference, the radial temperature difference, and the equivalent average temperature.

[0161] In some embodiments, the response data determination module 303, in specific implementation, divides the measured dielectric response data into multiple frequency band dielectric response data according to the test frequency corresponding to the measured dielectric response data; for each frequency band dielectric response data, a compensation parameter corresponding to the frequency band dielectric response data is determined according to the internal temperature gradient descriptor, the operating condition data, and the preset reference condition; each frequency band dielectric response data is compensated using the compensation parameter corresponding to each frequency band dielectric response data to determine multiple compensated dielectric response data; and the target dielectric response data is determined based on the multiple compensated dielectric response data.

[0162] In some embodiments, the response data determination module 303, in specific implementation, when the current-carrying current, the environmental boundary data, and the multi-point temperature data of the outer surface are all within their respective preset effective ranges, and the acquisition duration of the measured dielectric response data is greater than a preset duration or the operating condition stability during the test period is lower than a preset stability threshold, for each test frequency point in the measured dielectric response data, according to the test time period corresponding to the test frequency point, determines the frequency point temperature data and the frequency point operating condition data; according to the frequency point temperature data and the frequency point operating condition data, determines the frequency point temperature gradient descriptor; according to the frequency point temperature gradient descriptor, the frequency point operating condition data, and the preset reference operating condition, determines the frequency point compensation parameter, and uses the frequency point compensation parameter to compensate the corresponding dielectric response quantity to determine the frequency point compensated dielectric response quantity; and according to each of the frequency point compensated dielectric response quantities, determines the target dielectric response data.

[0163] In some embodiments, the result determination module 304 specifically acquires preset health reference dielectric response data corresponding to the target high-voltage DC bushing; determines low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, and high-frequency dielectric response characteristics based on the target dielectric response data; determines dielectric response residual characteristics based on the target dielectric response data and the preset health reference dielectric response data; determines moisture state indicators, aging state indicators, and abnormal state indicators based on the low-frequency dielectric response characteristics, the mid-frequency dielectric response characteristics, the high-frequency dielectric response characteristics, and the dielectric response residual characteristics; and determines the insulation state diagnosis result based on the moisture state indicators, the aging state indicators, and the abnormal state indicators.

[0164] In some embodiments, the above-described device further includes: determining data integrity and operating condition stability based on the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data; determining compensation effectiveness based on the compensation parameters corresponding to each frequency band dielectric response data and a preset compensation parameter range; determining diagnostic confidence based on the data integrity, the operating condition stability, and the compensation effectiveness; and determining a diagnostic output result based on the diagnostic confidence and the insulation state diagnostic result; wherein, when the diagnostic confidence is lower than a preset confidence threshold, the diagnostic output result includes a retest prompt.

[0165] It should be noted that the units, devices, or modules described in the above embodiments can be implemented by computer chips or physical entities, or by products with certain functions. For ease of description, the above devices are described by dividing them into various modules according to their functions. Of course, in implementing this specification, the functions of each module can be implemented in the same software and / or hardware, or modules that implement the same function can be implemented by a combination of sub-modules or sub-units, etc. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. For example, units or components can be combined or integrated into another system, or some features can be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection between the devices or units shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0166] As can be seen from the above, the high-voltage DC bushing dielectric response diagnostic device provided in the embodiments of this specification acquires the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference operating condition of the target high-voltage DC bushing; determines the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data; compensates the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition to determine the target dielectric response data under the preset reference operating condition; and determines the insulation state diagnostic result of the target high-voltage DC bushing based on the target dielectric response data.

[0167] In a specific scenario example, the dielectric response diagnostic method and device for high-voltage DC bushings provided in this specification can be applied to solve the problem of poor comparability of dielectric response data for high-voltage DC bushings under different operating conditions, leading to insufficient accuracy in insulation condition diagnosis. The specific implementation process may include the following:

[0168] S1: Data Acquisition.

[0169] Eight temperature measuring points are arranged axially on the outer surface of the target high-voltage DC bushing, including six measuring points on the main insulation section, one measuring point in the flange adjacent area, and one measuring point in the lead-out end area, to obtain multi-point temperature data of the outer surface.

[0170] The operating current is acquired by the current acquisition unit, and the ambient temperature, relative humidity and wind speed are acquired by the environmental parameter acquisition unit to determine the operating condition data.

[0171] The measured dielectric response data is obtained by connecting the measurement terminal or test tap of the target high-voltage DC bushing to a broadband disturbance measurement unit. The test frequency range corresponding to the measured dielectric response data is: .

[0172] The measured dielectric response data includes complex capacitance. Dielectric loss factor Complex permittivity and dielectric modulus One or more of them.

[0173] S2: Data preprocessing and operating condition judgment.

[0174] Based on the test time period corresponding to each test frequency point in the measured dielectric response data, the current carrying current, external surface multi-point temperature data, ambient temperature, ambient relative humidity and wind speed within the test time period are mapped to the corresponding test frequency point.

[0175] The measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data are subjected to physical boundary checks and statistical outlier removal. For short-term missing data, linear interpolation or adjacent measurement point fitting is used for repair. For data windows with continuous missing time exceeding a preset threshold, the data window is marked as a low-confidence window.

[0176] Calculate the relative fluctuation rate of the current-carrying current within the test window: .

[0177] When the relative fluctuation rate of the current-carrying current, the rate of change of ambient temperature, and the rate of change of external surface temperature all simultaneously meet the preset threshold requirements, the current test window is determined to be a quasi-steady-state condition. When the above conditions are not simultaneously met, a frequency-by-frequency compensation method is adopted.

[0178] S3: Determine the descriptor of the internal temperature gradient.

[0179] Based on the multi-point temperature data of the outer surface and the current-carrying current, ambient temperature, ambient relative humidity and wind speed in the operating condition data, the temperature of multiple internal regions of the target high voltage DC bushing is determined using a preset segmented thermal network model.

[0180] The temperatures of the multiple internal regions include the conductor adjacent layer temperature, the intermediate insulation layer temperature, the outer surface layer temperature, the equivalent temperature of the flange region, and the equivalent temperature of the main insulation region.

[0181] Based on the temperatures of the multiple internal regions, the equivalent average temperature, axial temperature difference, radial temperature difference, temperature difference between the flange area and the main insulation area, and hot spot correction factor are determined. Furthermore, based on the equivalent average temperature, the axial temperature difference, the radial temperature difference, the temperature difference between the flange area and the main insulation area, and the hot spot correction factor, the internal temperature gradient descriptor is determined. .

[0182] S4: Determine the target dielectric response data.

[0183] The preset reference operating condition is set as follows: .

[0184] The reference environmental boundary conditions can be expressed as: .

[0185] In this embodiment, It is 45 ℃. It is 0.8 times the rated current. It is 25 ℃. 50%, The value is 0.5 m / s; the above reference parameters correspond to the same stable reference condition.

[0186] Based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition, the measured dielectric response data is jointly compensated: .

[0187] For low-frequency band, mid-frequency band and high-frequency band, let Frequency correction factors were used respectively. Amplitude correction factor and bias correction amount Perform frequency band compensation: .

[0188] After compensation is completed, the target dielectric response data under the preset reference operating condition is determined, and the target dielectric response data forms the equivalent dielectric response curve under the preset reference operating condition.

[0189] S5: Determine the insulation condition diagnosis results.

[0190] Based on the target dielectric response data, determine the low-frequency dielectric loss slope, peak frequency of the imaginary part of the dielectric modulus, peak value of the imaginary part of the dielectric modulus, peak value of the imaginary part of the complex dielectric constant, broadband integral area, rate of change of complex capacitance, residual of the health reference curve, low-frequency to mid-frequency loss ratio, and high-frequency capacitance stability index.

[0191] Based on the above characteristics, a diagnostic feature vector is determined, and the diagnostic feature vector is then normalized to obtain a normalized diagnostic feature vector. Z d .

[0192] Based on the normalized diagnostic feature vector Z d Determine the moisture status indicators respectively Aging status indicators and abnormal status indicators : , , .

[0193] in, , and These represent the weight vectors corresponding to the scores for dampness, aging, and abnormality, respectively. , and These represent the corresponding biases. This represents the normalized diagnostic feature vector.

[0194] Based on the moisture condition index, the aging condition index, and the abnormal condition index, the insulation condition diagnosis result of the target high-voltage DC bushing is determined. , , When the insulation condition diagnosis result is determined to be normal, then... ,or ,or If the insulation condition diagnosis result is positive, it is determined to be an abnormal state. Otherwise, the insulation condition diagnosis result is determined to be a state of concern.

[0195] When the moisture condition index increases significantly while the aging condition index shows little change, the insulation condition diagnosis result is determined to be a moisture-dominated anomaly. When the aging condition index increases significantly while the moisture condition index changes little, the insulation condition diagnosis result is determined to be an aging-dominated anomaly. When both the moisture condition index and the aging condition index increase simultaneously, or when the abnormal condition index remains persistently high, the insulation condition diagnosis result is determined to be a composite anomaly or other anomaly.

[0196] S6: Diagnostic confidence and trend warning.

[0197] Based on the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data, the data integrity and operating condition stability are determined, and the compensation effectiveness is determined based on the temperature inversion model residual and the dielectric response compensation residual; based on the data integrity, the operating condition stability, and the compensation effectiveness, the diagnostic confidence level is determined.

[0198] in, Indicates the confidence level of the diagnosis. , , and These represent the normalized evaluation values ​​for data integrity, operating condition stability, temperature inversion effectiveness, and dielectric response compensation effectiveness, respectively.

[0199] When the diagnostic confidence level is lower than a preset confidence threshold, a diagnostic output result is determined based on the diagnostic confidence level and the insulation status diagnostic result, and the diagnostic output result includes a low confidence level prompt.

[0200] Simultaneously, time series are established for the moisture status indicator, the aging status indicator, and the abnormal status indicator, and the corresponding growth rate is determined. When any status indicator has not yet reached the abnormal threshold, but the corresponding growth rate exceeds the preset growth rate threshold, the diagnostic output includes a trend warning.

[0201] In some embodiments, see Figure 4 As shown, measured dielectric response data, multi-point temperature data of the outer surface, current-carrying current, and environmental boundary data of the target high-voltage DC bushing are acquired respectively. The measured dielectric response data, multi-point temperature data of the outer surface, current-carrying current, and environmental boundary data are then time-synchronized and preprocessed. Based on the multi-point temperature data of the outer surface, the current-carrying current, and the environmental boundary data, the temperatures of multiple internal regions of the target high-voltage DC bushing are inverted, and an internal temperature gradient descriptor is constructed based on the temperatures of these multiple internal regions. G T Set a preset reference condition Ω0, and describe the internal temperature gradient. GT The current-carrying current I The environmental boundary data B Using the preset reference condition Ω0 as the compensation input, the measured dielectric response data is subjected to frequency band compensation or frequency point-by-frequency compensation to determine the target dielectric response data after compensation; the compensated dielectric response features are extracted based on the target dielectric response data, and the moisture state index is determined based on the compensated dielectric response features. M Aging status indicators A and abnormal status indicators D The insulation status diagnosis results of the target high-voltage DC bushing are obtained. At the same time, the diagnostic confidence is evaluated based on data integrity, operating condition stability and compensation effectiveness, and trend warning is given in combination with historical diagnostic results.

[0202] In some embodiments, see Figure 5 As shown, based on the test frequency corresponding to the measured dielectric response data, the measured dielectric response data is divided into a low-frequency band Λ. L Mid-frequency band Λ M and high frequency band Λ H The low-frequency band corresponds to low-frequency dielectric response data, the mid-frequency band corresponds to mid-frequency dielectric response data, and the high-frequency band corresponds to high-frequency dielectric response data. For each frequency band, the corresponding frequency correction factor, amplitude correction factor, and bias correction amount are determined according to the internal temperature gradient descriptor, the operating condition data, and the preset reference condition. The dielectric response data of the corresponding frequency band are compensated using the compensation parameters corresponding to each frequency band to obtain low-frequency band compensated dielectric response data, mid-frequency band compensated dielectric response data, and high-frequency band compensated dielectric response data, respectively. Then, the compensated dielectric response data of each frequency band are combined according to the test frequency order to determine the target dielectric response data under the preset reference condition.

[0203] In some embodiments, see Figure 6 As shown, based on the test frequency corresponding to the measured dielectric response data, 10 - The test frequency range from 3 Hz to 10³ Hz is divided into the low frequency band Λ. L Mid-frequency band Λ M and high frequency band Λ H Among them, the low frequency band Λ L The frequency range is 10 - ³ Hz≤ f <10 - ¹ Hz, mid-band Λ M The frequency range is 10 - ¹ Hz≤ f <10¹ Hz, high frequency band Λ H The frequency range is 10¹ Hz ≤f ≤10³ Hz, f The test frequency is indicated. Based on the frequency band to which each test frequency belongs, the measured dielectric response data are respectively determined as low-frequency band dielectric response data, mid-frequency band dielectric response data, and high-frequency band dielectric response data. For each frequency band dielectric response data, corresponding compensation parameters are determined based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition, to perform differentiated compensation for the dielectric response data of different frequency bands, thereby determining the target dielectric response data under the preset reference operating condition.

[0204] While this specification provides the steps of operation for the methods described in the embodiments or flowcharts, more or fewer steps may be included based on conventional or non-inventive means. The order of steps listed in the embodiments is merely one possible order of execution among many steps and does not represent the only possible order. In actual device or client product execution, the methods shown in the embodiments or drawings may be executed sequentially or in parallel (e.g., in a parallel processor or multi-threaded processing environment, or even a distributed data processing environment). The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, product, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, product, or apparatus. Without further limitations, the presence of other identical or equivalent elements in a process, method, product, or apparatus that includes said elements is not excluded. The terms "first," "second," etc., are used to denote names and do not indicate any particular order.

[0205] Those skilled in the art will also know that, besides implementing the controller using purely computer-readable program code, the same functions can be achieved by logically programming the method steps, making the controller function as logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices within it used to implement various functions can also be considered structures within that hardware component. Alternatively, the devices used to implement various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0206] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this specification can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of this specification can essentially be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, mobile terminal, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments of this specification.

[0207] Although this specification has been described by way of examples, those skilled in the art will recognize that many variations and modifications are possible without departing from the spirit of this specification, and it is intended that the appended claims cover such variations and modifications without departing from the spirit of this specification.

Claims

1. A method for diagnosing dielectric response of a high voltage DC bushing, characterized by, include: Acquire measured dielectric response data, multi-point temperature data of the outer surface, operating condition data, and preset reference conditions of the target high-voltage DC bushing; Based on the multi-point temperature data of the outer surface and the operating condition data, the internal temperature gradient descriptor of the target high-voltage DC bushing is determined; Based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition, the measured dielectric response data is compensated to determine the target dielectric response data under the preset reference condition. Based on the target dielectric response data, the insulation status diagnosis result of the target high-voltage DC bushing is determined.

2. The method of claim 1, wherein, The operating condition data includes current-carrying current and environmental boundary data. Determining the internal temperature gradient descriptor of the target high-voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data includes: Using a pre-defined segmented thermal network model, the initial temperatures of multiple internal regions of the target high-voltage DC bushing are determined based on the current-carrying current and the environmental boundary data. Based on the multi-point temperature data of the outer surface, the initial temperature corresponding to the multiple internal regions is corrected to determine the temperature of the multiple internal regions; The internal temperature gradient descriptor is determined based on the temperatures of the multiple internal regions.

3. The method of claim 2, wherein, The plurality of internal regions include a plurality of axial regions distributed along the axis of the target high-voltage DC bushing and a plurality of radial regions distributed along the radial direction of the target high-voltage DC bushing. Determining the internal temperature gradient descriptor based on the temperature of the plurality of internal regions includes: The axial temperature difference is determined based on the temperatures corresponding to the multiple axial regions. The radial temperature difference is determined based on the temperatures corresponding to the multiple radial regions; The equivalent average temperature is determined based on the temperatures of the multiple internal regions. The internal temperature gradient descriptor is determined based on the axial temperature difference, the radial temperature difference, and the equivalent average temperature.

4. The method of claim 1, wherein, The step of compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference operating condition to determine the target dielectric response data under the preset reference operating condition includes: Based on the test frequency corresponding to the measured dielectric response data, the measured dielectric response data is divided into multiple frequency band dielectric response data. For each band dielectric response data, compensation parameters corresponding to the band dielectric response data are determined based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition. Using the compensation parameters corresponding to the dielectric response data of each frequency band, the dielectric response data of each frequency band is compensated to determine multiple compensated dielectric response data; The target dielectric response data is determined based on the plurality of compensated dielectric response data.

5. The method of claim 4, wherein, The operating condition data includes current-carrying current and environmental boundary data. When the current-carrying current, the environmental boundary data, and the multi-point temperature data of the outer surface are all within their respective preset effective ranges, and the acquisition duration of the measured dielectric response data is greater than a preset duration or the operating condition stability during the test is lower than a preset stability threshold, the step of compensating the measured dielectric response data based on the internal temperature gradient descriptor, the operating condition data, and the preset reference condition to determine the target dielectric response data under the preset reference condition includes: For each test frequency point in the measured dielectric response data, the frequency point temperature data and frequency point operating condition data corresponding to the test frequency point are determined according to the test time period corresponding to the test frequency point. Based on the frequency point temperature data and the frequency point operating condition data, determine the frequency point temperature gradient descriptor corresponding to the test frequency point; Based on the frequency point temperature gradient descriptor, the frequency point operating condition data, and the preset reference condition, determine the frequency point compensation parameter corresponding to the test frequency point, and use the frequency point compensation parameter to compensate the dielectric response corresponding to the test frequency point to determine the frequency point compensation dielectric response. The target dielectric response data is determined based on the frequency point compensation dielectric response corresponding to each of the test frequency points.

6. The method of claim 1, wherein, The step of determining the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data includes: Obtain the preset health reference dielectric response data corresponding to the target high voltage DC bushing; Based on the target dielectric response data, determine the low-frequency dielectric response characteristics, mid-frequency dielectric response characteristics, and high-frequency dielectric response characteristics; Based on the target dielectric response data and the preset healthy reference dielectric response data, the dielectric response residual characteristics are determined; Based on the low-frequency dielectric response characteristics, the mid-frequency dielectric response characteristics, the high-frequency dielectric response characteristics, and the dielectric response residual characteristics, the moisture state index, aging state index, and abnormal state index are determined. The insulation condition diagnosis result is determined based on the moisture condition index, the aging condition index, and the abnormal condition index.

7. The method of claim 5, wherein, The method further includes: Based on the measured dielectric response data, the multi-point temperature data of the outer surface, and the operating condition data, the data integrity and operating condition stability are determined. The compensation parameters corresponding to each of the frequency band dielectric response data are compared with the corresponding preset compensation parameter range, or the frequency point compensation parameters corresponding to each of the test frequency points are compared with the corresponding preset compensation parameter range, and the compensation effectiveness is determined based on the comparison results. The diagnostic confidence level is determined based on the data integrity, the operating condition stability, and the compensation effectiveness. Based on the diagnostic confidence level and the insulation status diagnostic result, a diagnostic output result is determined; wherein, when the diagnostic confidence level is lower than a preset confidence threshold, the diagnostic output result includes a retest prompt.

8. A high voltage DC bushing dielectric response diagnostic device, characterized by, include: The data acquisition module is used to acquire the measured dielectric response data, multi-point temperature data of the outer surface, operating condition data and preset reference conditions of the target high voltage DC bushing. The descriptive quantity determination module is used to determine the internal temperature gradient descriptive quantity of the target high voltage DC bushing based on the multi-point temperature data of the outer surface and the operating condition data. The response data determination module is used to compensate the measured dielectric response data based on the internal temperature gradient description, the operating condition data, and the preset reference condition, and to determine the target dielectric response data under the preset reference condition. The result determination module is used to determine the insulation status diagnosis result of the target high-voltage DC bushing based on the target dielectric response data.

9. An electronic device, comprising: It includes a processor and a memory for storing processor-executable instructions, wherein the processor, when executing the instructions, implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores computer instructions that, when executed by a processor, implement the steps of the method according to any one of claims 1 to 7.

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