A method and system for evaluating the aging state of a zinc oxide voltage-dependent resistor for a direct current lightning arrester

Abstract

The application belongs to the technical field of state evaluation of zinc oxide varistor for DC arrester, and discloses a method and system for evaluating the aging state of zinc oxide varistor for DC arrester. The method is characterized in that: a single-side coated parallel silver electrode is applied to the zinc oxide varistor, a DC aging voltage is applied to the channel between the two electrodes, and the X-ray diffraction peak position of the (002) crystal plane of the ZnO varistor at the channel and the Zn2p orbital peak position are tested under the conditions of no aging and different aging times. The aging state of the zinc oxide varistor is evaluated according to the offset degree of the (002) diffraction peak and the Zn2p orbital peak, so that the aging state of the zinc oxide varistor for DC arrester is determined at the level of grain boundary physicochemical layer. The aging state of the zinc oxide varistor for DC arrester can be accurately evaluated, and the reliability of the evaluation result of the aging state of the zinc oxide varistor for DC arrester is improved.

Description

A method and system for assessing the aging condition of zinc oxide varistors used in DC surge arresters. Technical Field

[0001] This invention relates to the field of condition assessment technology for zinc oxide varistors used in DC surge arresters, and particularly to a method and system for assessing the aging condition of zinc oxide varistors used in DC surge arresters. Background Technology

[0002] ZnO varistors possess excellent nonlinear volt-ampere characteristics and are core components of DC surge arresters, widely used in power systems for overvoltage protection to maintain the safe and stable operation of power equipment. Because ZnO varistors operate in parallel with power equipment for extended periods, aging is inevitable, typically manifested as an increase in power dissipation (leakage current), posing a potential threat to the insulation protection level of the power equipment. However, with advancements in manufacturing technology, the power dissipation of zinc oxide varistors no longer increases in a static manner. Based on aging power dissipation trends, ZnO varistors can be categorized into stable, metastable, and unstable types. Stable varistors show a continuous decrease in power dissipation with increasing aging time; metastable varistors initially decrease and then continuously increase in power dissipation; and unstable varistors show a continuous increase in power dissipation with increasing aging time.

[0003] Currently, the aging condition assessment of DC surge arresters mainly relies on the Arenius formula to analyze the increased power dissipation (leakage current). However, the non-Areneus aging characteristics of stable ZnO varistors are difficult to evaluate through power dissipation; at the same time, power dissipation exhibits significant voltage dependence and is significantly affected by ambient temperature and atmosphere, making it difficult to accurately characterize the aging degree of ZnO varistors, thus limiting the further development and application of DC surge arresters. Summary of the Invention

[0004] This invention provides a method and system for evaluating the aging status of zinc oxide varistors used in DC surge arresters, solving the technical problem of unreliable evaluation results of the aging resistance of ZnO varistors used in DC surge arresters.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for assessing the aging status of zinc oxide varistors used in DC surge arresters, comprising:

[0007] Obtain a zinc oxide varistor sample for DC surge arrester used for aging condition assessment test; wherein, one side of the zinc oxide varistor sample for DC surge arrester is covered with parallel silver electrodes, and a test channel is reserved in the middle of the one side.

[0008] X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channels to obtain the binding energy of the ZnO (002) crystal plane and Zn2p orbital before aging.

[0009] Accelerated aging tests were conducted on zinc oxide varistors for DC surge arresters for different preset time lengths to obtain test channels with different aging degrees. The accelerated aging test included applying a DC aging voltage to parallel silver electrodes while heating the zinc oxide varistors for DC surge arresters.

[0010] X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channels with different aging degrees to obtain the binding energies of ZnO(002) crystal planes and Zn2p orbitals with different aging degrees. The degree of shift of the binding energies of ZnO(002) crystal planes and Zn2p orbitals with different aging degrees relative to the binding energies of ZnO(002) crystal planes and Zn2p orbitals when unaged was determined as the aging state evaluation result of the zinc oxide varistor.

[0011] As an optional embodiment of the present invention, heating the zinc oxide varistor sample for a DC surge arrester includes:

[0012] When heating the zinc oxide varistor sample for DC surge arrester, the zinc oxide varistor sample for DC surge arrester is placed on an alumina heating plate, and the alumina heating plate is used to heat the zinc oxide varistor sample for DC surge arrester.

[0013] As an optional embodiment of the present invention, one side of the zinc oxide varistor sample for DC surge arrester is coated with a parallel silver electrode; wherein, the parallel silver electrode is obtained by ion sputtering or low-temperature silver paste coating on one side of the zinc oxide varistor sample for DC surge arrester.

[0014] As an optional embodiment of the present invention, the width of the test channel is 0.5~1 mm.

[0015] As an optional embodiment of the present invention, X-ray diffraction spectroscopy is performed in the following manner:

[0016] X-ray diffraction spectroscopy was performed using an X-ray diffractometer. The X-ray diffractometer had a scanning range of 10–80°, a scanning speed of 4° / min, a step size of 0.02°, and used Cu target radiation with a working voltage of 40 kV to obtain diffraction peaks of the ZnO(002) crystal plane.

[0017] As an optional embodiment of the present invention, X-ray photoelectron spectroscopy testing is performed in the following manner:

[0018] X-ray photoelectron spectroscopy was performed using an X-ray photoelectron spectrometer. The binding energy range of the X-ray photoelectron spectrometer was 0–1350 eV, with a step size of less than or equal to 0.1 eV, to obtain the orbital peak of Zn2p.

[0019] As an optional embodiment of the present invention, when applying a DC aging voltage to the parallel silver electrode, the DC aging voltage is applied to one side of the parallel silver electrode and the other side of the parallel silver electrode is grounded. The applied DC aging voltage is 0.8~0.9U1mA, where U1mA is the voltage corresponding to a current of 1 mA flowing through the channel.

[0020] As an optional embodiment of the present invention, when heating the zinc oxide varistor sample for DC surge arrester, the aging temperature is set to 100℃~180℃.

[0021] As an optional aspect of this invention, the degree of shift in the binding energy of the ZnO(002) crystal plane and Zn2p orbitals under different aging degrees compared to the binding energy of the ZnO(002) crystal plane and Zn2p orbitals when unaged is determined as the aging state assessment result of the zinc oxide varistor, including:

[0022] The binding energies of ZnO(002) crystal planes and Zn2p orbitals under different aging degrees were compared with the corresponding binding energies of ZnO(002) crystal planes and Zn2p orbitals under unaged conditions.

[0023] If the diffraction peaks of the ZnO (002) crystal plane and the orbital peak positions of the Zn2p orbital binding energy remain unchanged, it is determined that the aging degree of the zinc oxide varistor used in the DC surge arrester is relatively small.

[0024] If the diffraction peak of the ZnO(002) crystal plane decreases by more than 0.02°, or the orbital peak of the Zn2p orbital binding energy decreases by more than 0.5 eV, then the zinc oxide varistor used in the DC surge arrester is considered to be severely aged.

[0025] In a second aspect, the present invention provides a system for implementing the above-described method for assessing the aging status of zinc oxide varistors used in DC surge arresters, comprising:

[0026] X-ray diffractometer is used to perform X-ray diffraction spectroscopy tests on unaged and different aging test channels to obtain the ZnO(002) crystal plane when unaged, and the ZnO(002) crystal plane when different aging.

[0027] X-ray photoelectron spectrometer is used to perform X-ray photoelectron spectroscopy tests on unaged and different aging test channels to obtain the Zn2p orbital binding energy when unaged, as well as the Zn2p orbital binding energy when different aging levels.

[0028] The comparative evaluation module is used to determine the degree of shift of the binding energy of the ZnO(002) crystal plane and Zn2p orbital under different aging levels compared with the binding energy of the ZnO(002) crystal plane and Zn2p orbital when unaged, and to evaluate the aging status of the zinc oxide varistor.

[0029] As can be seen from the above technical solutions, the present invention has the following advantages:

[0030] This invention involves coating a single side of a ZnO varistor used in DC surge arresters with parallel silver electrodes and subjecting the surface channel between the silver electrodes to DC aging. XRD and XPS spectra of the unaged and different aging stages of this channel region are tested to obtain the distribution of ZnO(002) diffraction peaks and Zn2p orbital peaks. This allows for the determination of the shift of ZnO(002) diffraction peaks and Zn2p orbital peaks after aging. The aging state of the ZnO varistor used in DC surge arresters is determined at the physicochemical structure level, avoiding the inaccurate assessment of aging state based on power consumption (leakage current). This provides a precise evaluation of the aging resistance of ZnO varistors used in DC surge arresters, improving the reliability of the aging resistance assessment results. Attached Figure Description

[0031] Figure 1 is a flowchart of an aging status assessment method for zinc oxide varistors used in DC surge arresters according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the aging test scheme for zinc oxide varistors used in DC surge arresters provided in an embodiment of the present invention.

[0033] Figure 3 is a schematic diagram of the diffraction peaks of ZnO(002) under different aging states provided by the embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of Zn2p orbital peaks under different aging states in XPS testing provided in an embodiment of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The core component of a DC surge arrester is the ZnO varistor. Under normal operating conditions, DC surge arresters are connected in parallel with power equipment and need to withstand the system voltage, thus undergoing aging. Previously, the aging state of the arrester could be determined by monitoring the leakage current flowing through it; the higher the leakage current, the more severe the aging. However, the leakage current of stable DC surge arresters decreases during the aging process. Therefore, this solution presents a physicochemical testing method, using changes in microstructure to determine aging.

[0037] Example 1

[0038] As shown in Figure 1, a method for assessing the aging status of zinc oxide varistors used in DC surge arresters includes:

[0039] S1. Obtain a zinc oxide varistor sample for DC surge arrester used for aging condition assessment test; wherein, one side of the zinc oxide varistor sample for DC surge arrester is covered with parallel silver electrodes, and a test channel is reserved in the middle of the one side.

[0040] S2. X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channel to obtain the binding energy of the ZnO (002) crystal plane and Zn2p orbital when it was not aged.

[0041] S3. Accelerated aging tests of zinc oxide varistors for DC surge arresters are conducted for different preset time lengths to obtain test channels with different aging degrees. The accelerated aging test includes applying a DC aging voltage to the parallel silver electrodes while heating the zinc oxide varistors for DC surge arresters.

[0042] S4. X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channels with different aging degrees to obtain the binding energy of ZnO(002) crystal plane and Zn2p orbital at different aging degrees; the degree of shift of the binding energy of ZnO(002) crystal plane and Zn2p orbital at different aging degrees relative to the binding energy of ZnO(002) crystal plane and Zn2p orbital at the unaged state was determined as the aging state evaluation result of the zinc oxide varistor.

[0043] As an optional approach, step S4 involves heating the zinc oxide varistor sample for the DC surge arrester, including:

[0044] When heating the zinc oxide varistor sample for DC surge arrester, the zinc oxide varistor sample for DC surge arrester is placed on an alumina heating plate, and the alumina heating plate is used to heat the zinc oxide varistor sample for DC surge arrester.

[0045] As shown in Figure 2, as an optional solution, in step S1, one side of the zinc oxide varistor sample for DC surge arrester is coated with parallel silver electrodes; wherein, the surface of the zinc oxide varistor for DC surge arrester is clean and smooth, and the parallel silver electrodes are obtained by ion sputtering or low-temperature silver paste coating on one side of the zinc oxide varistor sample for DC surge arrester.

[0046] As an optional option, in step S1, the width of the test channel is 0.5~1 mm.

[0047] As an optional approach, in steps S1 and S4, the X-ray diffraction spectroscopy is performed in the following manner:

[0048] X-ray diffraction spectroscopy (XRD) was performed using an X-ray diffractometer. The X-ray diffractometer had a scanning range of 10–80°, a scanning speed of 4° / min, a step size of less than or equal to 0.02°, and used Cu target radiation with a working voltage of 40 kV to obtain diffraction peaks of the ZnO(002) crystal plane.

[0049] As an optional approach, in steps S1 and S4, the X-ray photoelectron spectroscopy (XPS) test is performed as follows:

[0050] X-ray photoelectron spectroscopy was performed using an X-ray photoelectron spectrometer. The binding energy range of the X-ray photoelectron spectrometer was 0–1350 eV, with a step size of less than or equal to 0.1 eV, to obtain the orbital peak of Zn2p.

[0051] As an optional solution, in step S3, when applying a DC aging voltage to the parallel silver electrodes, the DC aging voltage is applied to one side of the parallel silver electrodes, and the other side of the parallel silver electrodes is grounded. The applied DC aging voltage is 0.8~0.9U1mA, where U1mA is the voltage corresponding to a current flowing through the channel of 1 mA. In this solution, U1mA is taken as 200V. When heating the zinc oxide varistor sample for the DC surge arrester, the aging temperature is set to 100℃~180℃. The accelerated aging time is selected according to the actual situation, for example, 18h, 232h, 50h, 100h, 150h, 200h, etc. can be selected.

[0052] As an optional approach, in step S4, the XRD and XPS test positions of the aged zinc oxide varistor ceramic are located at the aging channel, which is basically consistent with the test positions of the unaged sample; the degree of shift of the binding energy of the ZnO(002) crystal plane and Zn2p orbital under different aging degrees relative to the binding energy of the ZnO(002) crystal plane and Zn2p orbital when unaged is determined as the aging state evaluation result of the zinc oxide varistor, including:

[0053] The binding energies of ZnO(002) crystal planes and Zn2p orbitals under different aging degrees were compared with the corresponding binding energies of ZnO(002) crystal planes and Zn2p orbitals under unaged conditions.

[0054] If the diffraction peaks of the ZnO (002) crystal plane and the orbital peak positions of the Zn2p orbital binding energy remain unchanged, it is determined that the aging degree of the zinc oxide varistor used in the DC surge arrester is relatively small.

[0055] If the diffraction peak of the ZnO(002) crystal plane decreases by more than 0.02°, or the orbital peak of the Zn2p orbital binding energy decreases by more than 0.5 eV, then the zinc oxide varistor used in the DC surge arrester is considered to be severely aged.

[0056] In the preferred embodiment, the diffraction peaks and Zn2p orbital peaks of the ZnO(002) crystal plane at different aging times are obtained by XRD and XPS tests. The diffraction peaks and Zn2p orbital peaks of the unaged and ZnO(002) crystal planes at different aging times are normalized. The positions of the normalized ZnO(002) diffraction peaks and Zn2p orbital peaks of the zinc oxide varistor are compared with those of the unaged varistor, as shown in Figures 3 and 4, respectively. In Figure 3, the position of the ZnO(002) diffraction peak remains basically unchanged after aging for 18 h, indicating that the aging degree of the zinc oxide varistor for DC surge arresters is relatively small. In Figure 3, the ZnO(002) diffraction peak decreases by 0.02° after aging for 232 h, and in Figure 4, the Zn2p orbital peak decreases by more than 0.7 eV after aging for 232 h, indicating that the aging degree of the zinc oxide varistor for DC surge arresters is severe.

[0057] It should be noted that the electrical performance of zinc oxide varistors used in DC surge arresters is controlled by the grain boundary barrier, which is composed of the depletion layer and grain boundary interface states. The aging of ZnO varistors mainly involves two physical processes: the spatial rearrangement of the depletion layer by ion migration and diffusion within the grain boundary barrier, and the neutralization of grain boundary migrated ions with grain boundary interface states. When the ion migration in the depletion layer is significant, it will cause distortion of the ZnO lattice, resulting in a reduction of the ZnO (002) diffraction peak; at the same time, when the mobile zinc interstitial filler in the depletion layer neutralizes the grain boundary interface states, it will consume the grain boundary interface states, corresponding to the reduction of Zn ions, and the binding energy of the Zn2p orbital peak will decrease.

[0058] Therefore, if the ZnO (002) diffraction peak position remains basically unchanged, it indicates that the ion migration is weak; if the Zn2p orbital peak position remains basically unchanged, it means that the movable zinc interstitial ions in the grain boundary depletion layer have not been neutralized with the grain boundary interface states, and the ZnO varistor has a relatively small degree of aging. Conversely, if the ZnO (002) diffraction peak position shifts significantly towards a smaller angle and the Zn2p orbital peak binding energy decreases significantly, it indicates that the ion migration is severe, and there is a significant neutralization phenomenon between the grain boundary interface states and the movable zinc interstitial ions in the depletion layer. In this case, the ZnO varistor undergoes irreversible degradation, corresponding to severe aging of the DC surge arrester.

[0059] Furthermore, the more the XRD diffraction peaks of the ZnO lattice shift to smaller angles, the more severe the lattice distortion and the more significant the ion migration behavior. The more the Zn2p orbital binding energy decreases in XPS tests, the more significant the surface Zn reduction reaction becomes, meaning that the consumption of interface states is more pronounced.

[0060] Example 2

[0061] This second embodiment, based on the first embodiment, provides specific experimental parameters, wherein:

[0062] In step S1, the width of the test channel is 0.5 mm.

[0063] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.01°. The step size of the X-ray photoelectron spectrometer is 0.05 eV.

[0064] In step S3, the applied DC aging voltage is 160V. The aging temperature is set to 100℃.

[0065] Example 3

[0066] This embodiment 3, based on embodiment 1, provides specific experimental parameters, wherein:

[0067] In step S1, the width of the test channel is 1 mm.

[0068] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.02°. The step size of the X-ray photoelectron spectrometer is 0.1 eV.

[0069] In step S3, the applied DC aging voltage is 180V. The aging temperature is set to 180℃.

[0070] Example 4

[0071] This Example 4, based on Example 1, provides specific experimental parameters, wherein:

[0072] In step S1, the width of the test channel is 0.8 mm.

[0073] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.01°. The step size of the X-ray photoelectron spectrometer is 0.05 eV.

[0074] In step S3, the applied DC aging voltage is 170V. The aging temperature is set to 150℃.

[0075] Example 5

[0076] This Example 5, based on Example 1, provides specific experimental parameters, wherein:

[0077] In step S1, the width of the test channel is 0.9 mm.

[0078] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.01°. The step size of the X-ray photoelectron spectrometer is 0.1 eV.

[0079] In step S3, the applied DC aging voltage is 170V. The aging temperature is set to 170℃.

[0080] Example 6

[0081] This Example 6, based on Example 1, provides specific experimental parameters, wherein:

[0082] In step S1, the width of the test channel is 0.5 mm.

[0083] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.02°. The step size of the X-ray photoelectron spectrometer is 0.08 eV.

[0084] In step S3, the applied DC aging voltage is 160V. The aging temperature is set to 130℃.

[0085] Example 7

[0086] This embodiment 7, based on embodiment 1, provides specific experimental parameters, wherein:

[0087] In step S1, the width of the test channel is 0.9 mm.

[0088] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.01°. The step size of the X-ray photoelectron spectrometer is 0.1 eV.

[0089] In step S3, the applied DC aging voltage is 180V. The aging temperature is set to 180℃.

[0090] Example 8

[0091] This embodiment 8, based on embodiment 1, provides specific experimental parameters, wherein:

[0092] In step S1, the width of the test channel is 1 mm.

[0093] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.02°. The step size of the X-ray photoelectron spectrometer is 0.02 eV.

[0094] In step S3, the applied DC aging voltage is 160V. The aging temperature is set to 180℃.

[0095] Example 9

[0096] This Example 9, based on Example 1, provides specific experimental parameters, wherein:

[0097] In step S1, the width of the test channel is 0.7 mm.

[0098] In steps S1 and S4, when performing X-ray diffraction spectroscopy, the step size of the X-ray diffractometer is 0.01°. The step size of the X-ray photoelectron spectrometer is 0.01 eV.

[0099] In step S3, the applied DC aging voltage is 160V. The aging temperature is set to 170℃.

[0100] Example 10

[0101] This embodiment 10 provides a system for implementing the aging condition assessment method for zinc oxide varistors used in DC surge arresters described in any of the above embodiments, comprising:

[0102] X-ray diffractometer is used to perform X-ray diffraction spectroscopy tests on unaged and different aging test channels to obtain the ZnO(002) crystal plane when unaged, and the ZnO(002) crystal plane when different aging.

[0103] X-ray photoelectron spectrometer is used to perform X-ray photoelectron spectroscopy tests on unaged and different aging test channels to obtain the Zn2p orbital binding energy when unaged, as well as the Zn2p orbital binding energy when different aging levels.

[0104] The comparative evaluation module is used to determine the degree of shift of the binding energy of the ZnO(002) crystal plane and Zn2p orbital under different aging levels compared with the binding energy of the ZnO(002) crystal plane and Zn2p orbital when unaged, and to evaluate the aging status of the zinc oxide varistor.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for assessing the aging status of zinc oxide varistors used in DC surge arresters, characterized in that, include: A zinc oxide varistor sample for DC surge arrester was obtained for aging condition assessment testing. One side of the sample was covered with a parallel silver electrode, and a test channel was reserved in the middle of the single side. X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channel to obtain the binding energy of the ZnO(002) crystal plane and Zn2p orbitals before aging. Accelerated aging tests were performed on the zinc oxide varistor sample for different preset time lengths to obtain test channels with different aging degrees. The accelerated aging test included applying a DC aging voltage to the parallel silver electrode while heating the zinc oxide varistor sample. X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy were performed on the test channels with different aging degrees to obtain the binding energy of the ZnO(002) crystal plane and Zn2p orbitals at different aging degrees. The binding energy of the ZnO(002) crystal plane and Zn2p orbitals at different aging degrees was determined. The degree of shift in the p-orbital binding energy relative to the binding energy of the ZnO(002) crystal plane and Zn2p orbitals when unaged is used as the aging state assessment result of the zinc oxide varistor. Determining the degree of shift in the binding energy of the ZnO(002) crystal plane and Zn2p orbitals under different aging degrees relative to the binding energy of the ZnO(002) crystal plane and Zn2p orbitals when unaged is used as the aging state assessment result of the zinc oxide varistor includes: comparing the binding energies of the ZnO(002) crystal plane and Zn2p orbitals under different aging degrees with the corresponding binding energies of the ZnO(002) crystal plane and Zn2p orbitals when unaged; if the diffraction peaks of the ZnO(002) crystal plane and the orbital peak positions of the Zn2p orbital binding energy remain unchanged, the aging degree of the zinc oxide varistor used in DC surge arresters is determined to be relatively small; if the diffraction peaks of the ZnO(002) crystal plane show a decrease of greater than or equal to 0.02°, or the orbital peak positions of the Zn2p orbital binding energy show a decrease of 0.5°... A drop of more than eV indicates that the zinc oxide varistor used in the DC surge arrester is severely aged.

2. The method for assessing the aging status of zinc oxide varistors used in DC surge arresters according to claim 1, characterized in that, Heating a zinc oxide varistor sample for a DC surge arrester includes: placing the zinc oxide varistor sample on an alumina heating plate and heating it using the alumina heating plate.

3. The method for assessing the aging status of zinc oxide varistors used in DC surge arresters according to claim 1, characterized in that, One side of the zinc oxide varistor sample for DC surge arrester is coated with parallel silver electrodes; wherein, the parallel silver electrodes are obtained by ion sputtering or low-temperature silver paste coating on one side of the zinc oxide varistor sample for DC surge arrester.

4. The method for assessing the aging status of zinc oxide varistors used in DC surge arresters according to claim 1, characterized in that, The width of the test channel is 0.5~1 mm.

5. The method for assessing the aging status of zinc oxide varistors used in DC surge arresters according to claim 1, characterized in that, X-ray diffraction spectroscopy is performed as follows: X-ray diffraction spectroscopy is conducted using an X-ray diffractometer; wherein the scanning range of the X-ray diffractometer is 10... The diffraction peaks of the ZnO(002) crystal plane were obtained by scanning at 80°, with a scanning speed of 4° / min and a step size of less than or equal to 0.02°, using Cu target radiation and a working voltage of 40 kV.

6. The method for assessing the aging status of zinc oxide varistors for DC surge arresters according to claim 1, characterized in that, When performing X-ray photoelectron spectroscopy (XPS) tests, the following procedure is followed: XPS tests are performed using an XPS spectrometer; the binding energy range of the XPS spectrometer is 0–1350 eV, with a step size less than or equal to 0.1 eV, to obtain the orbital peak of Zn2p.

7. The method for assessing the aging status of zinc oxide varistors used in DC surge arresters according to claim 1, characterized in that, When applying a DC aging voltage to the parallel silver electrodes, the DC aging voltage is applied to one side of the parallel silver electrodes, while the other side is grounded. The applied DC aging voltage is 0.8~0.9U. 1mA U 1mA This is the voltage corresponding to a current of 1 mA flowing through the channel.

8. The method for assessing the aging status of zinc oxide varistors for DC surge arresters according to claim 1, characterized in that, When heating the zinc oxide varistor sample for DC surge arrester, the aging temperature is set to 100℃~180℃.

9. A system for implementing the aging condition assessment method for zinc oxide varistors used in DC surge arresters according to any one of claims 1 to 8, characterized in that, include: X-ray diffractometer is used to perform X-ray diffraction spectroscopy tests on unaged and different aging test channels to obtain the ZnO(002) crystal plane when unaged, and the ZnO(002) crystal plane when different aging. X-ray photoelectron spectrometer is used to perform X-ray photoelectron spectroscopy tests on unaged and different aging test channels to obtain the Zn2p orbital binding energy when unaged, as well as the Zn2p orbital binding energy when different aging levels. The comparative evaluation module is used to determine the degree of shift of the binding energy of the ZnO(002) crystal plane and Zn2p orbital under different aging levels compared with the binding energy of the ZnO(002) crystal plane and Zn2p orbital when unaged, and to evaluate the aging status of the zinc oxide varistor.

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