An evaluation method for 110kV oil-paper insulation bushing X wax equivalent content considering the influence of moisture

Abstract

The present application relates to a kind of 110kV oil paper insulation bushing X wax equivalent content evaluation method considering the influence of being affected by tide, belong to high voltage electrical equipment insulation state evaluation technical field.The method includes: the 110kV oil paper insulation bushing under different affected by tide state is carried out frequency domain dielectric spectrum test, obtains the relative dielectric parameter data under different frequency, based on the data constructs complex relative dielectric constant expression form, and using D-H dielectric parameter relaxation model extracts and is related to the multiple characteristic parameters of low-frequency conduction, polarization relaxation and loss peak characteristics, then, with reference state sample as reference, the characteristic parameters are normalized and comprehensive calculation, establish the X wax evaluation index considering the influence of being affected by tide, finally, according to the evaluation index, the X wax equivalent content state induced by the affected by tide of bushing is evaluated.

Description

Technical Field

[0001] This invention relates to the field of insulation condition assessment technology for high-voltage electrical equipment, and specifically to a method for assessing the equivalent wax content of 110kV oil-paper insulating bushings, taking into account the effects of moisture. Background Technology

[0002] Oil-paper insulated bushings are widely used in power equipment with voltage levels of 110kV and above, and their insulation performance directly affects the safety and reliability of equipment operation. During long-term operation, the bushing insulation is susceptible to moisture absorption due to environmental humidity, temperature, and electric fields, which further induces the formation of internal X-wax. This alters the conductivity, polarization relaxation, and dielectric loss characteristics of the oil-paper insulation system, ultimately reflected in the frequency domain dielectric response. While existing technologies can analyze the moisture absorption or overall insulation status of bushings, they lack effective and targeted assessment methods for the degree of X-wax formation induced by moisture, especially making it difficult to directly obtain its absolute content through non-destructive electrical testing. Therefore, it is necessary to propose a method for assessing the equivalent X-wax content of 110kV oil-paper insulated bushings that takes into account the effects of moisture absorption, in order to evaluate the equivalent X-wax content state induced by moisture absorption. Summary of the Invention

[0003] To address the shortcomings of the existing technology, this invention proposes a method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings, taking into account the effects of moisture.

[0004] To achieve the above objectives, the technical solution of the present invention is: a method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, comprising the following steps:

[0005] Step 1: Preparing oil-paper insulating sleeves for different moisture levels:

[0006] Six sets of brand-new 110kV oil-paper insulating bushing samples of the same model were selected. The oil plugs on the oil conservator of each bushing were removed. The samples were placed in constant temperature and humidity chambers and treated for 10, 20, 30, 40, 50 and 60 days under the same temperature and humidity conditions. A total of six sets of samples with different moisture conditions were obtained.

[0007] Step 2: Measurement of relative permittivity:

[0008] Frequency domain dielectric spectroscopy was used to test the dielectric spectra of six groups of samples under different moisture conditions. The test frequencies were 0.001 Hz, 0.00215 Hz, 0.00464 Hz, 0.01 Hz, 0.0215 Hz, 0.0464 Hz, 0.1 Hz, 0.215 Hz, 0.464 Hz, 1.00 Hz, 2.15 Hz, 4.64 Hz, 10.0 Hz, 21.5 Hz, 46.4 Hz, 100 Hz, 215 Hz, 464 Hz, and 1000 Hz. The relative dielectric parameters under different moisture conditions were obtained.

[0009] Step 3: Extraction of feature parameters:

[0010] The frequency domain data of each sample obtained in the second step are expressed in the form of complex relative permittivity, and the characteristic parameters in the model are extracted using the DH dielectric parameter relaxation model, namely relaxation intensity Χ1(0) and characteristic angular frequency ω. c Shape parameters n1 and p, loss peak relaxation intensity Χ2(0), loss peak characteristic angular frequency ω p The loss peak shape parameters n2 and m, and the DC conductivity σ;

[0011] Step 4: Calculation of X-wax evaluation indicators

[0012] Using formula (1), an evaluation index for the equivalent wax content of 110kV bushings considering the influence of moisture is constructed:

[0013]

[0014] Among them, Χ 1,base (0), ω c,base n 1,base p base , Χ 2,base (0), ω p,base n 2,base m base , σ base The characteristic parameters extracted from 110kV insulating bushings of the same model, batch, and without moisture were used to classify and evaluate the equivalent content level of X wax induced by moisture inside the bushing based on the value of κ. When 0.63212≤κ≤0.76931, the content of X wax caused by moisture was low; when 0.76931<κ≤0.82982, the content of X wax caused by moisture was high; and when 0.82982<κ≤1, the content of X wax caused by moisture was high.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This invention provides a method for assessing the equivalent X-wax content of 110kV oil-paper insulating bushings that takes into account the effects of moisture. Instead of relying on a single dielectric parameter to determine the bushing insulation state, it simultaneously introduces multiple key characteristic parameters related to low-frequency conductivity, polarization relaxation, and loss peak changes in the frequency domain dielectric response. These parameters characterize the variation patterns of different dielectric response characteristics within the bushing insulation under moisture conditions. Furthermore, an X-wax assessment index is established to achieve a comprehensive characterization of the equivalent X-wax content state induced by moisture. This provides a technical approach for assessing the X-wax state induced by moisture within 110kV oil-paper insulating bushings. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings, taking into account the effect of moisture. Detailed Implementation

[0018] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] Since moisture in the oil-paper insulating sleeve will enhance the conductivity of the oil-paper insulation system, change the polarization relaxation process, and further lead to the precipitation of X wax and the development of non-uniform structure, this invention selects parameters in the DH model that can characterize different response mechanisms as the basis for evaluation.

[0020] like Figure 1 As shown, a method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings, taking into account the effect of moisture, includes the following steps:

[0021] Step 1: Preparing oil-paper insulating sleeves for different moisture levels:

[0022] Six sets of brand-new 110kV oil-paper insulating bushing samples of the same model were selected. The oil plugs on the oil conservator of each bushing were removed. The samples were placed in constant temperature and humidity chambers and treated for 10, 20, 30, 40, 50 and 60 days under the same temperature and humidity conditions. A total of six sets of samples with different moisture conditions were obtained.

[0023] Step 2: Measurement of relative permittivity:

[0024] Frequency domain dielectric spectroscopy was used to test the dielectric spectra of six groups of samples under different moisture conditions. The test frequencies were 0.001 Hz, 0.00215 Hz, 0.00464 Hz, 0.01 Hz, 0.0215 Hz, 0.0464 Hz, 0.1 Hz, 0.215 Hz, 0.464 Hz, 1.00 Hz, 2.15 Hz, 4.64 Hz, 10.0 Hz, 21.5 Hz, 46.4 Hz, 100 Hz, 215 Hz, 464 Hz, and 1000 Hz. The relative dielectric parameters under different moisture conditions were obtained.

[0025] Step 3: Extraction of feature parameters:

[0026] The frequency domain data of each sample obtained in the second step are expressed in the form of complex relative permittivity, and the characteristic parameters in the model are extracted using the DH dielectric parameter relaxation model, namely relaxation intensity Χ1(0) and characteristic angular frequency ω. c Shape parameters n1 and p, loss peak relaxation intensity Χ2(0), loss peak characteristic angular frequency ω p The loss peak shape parameters n2 and m, and the DC conductivity σ;

[0027] Step 4: Calculation of X-wax evaluation indicators

[0028] Using formula (1), an evaluation index for the equivalent wax content of 110kV bushings considering the influence of moisture is constructed:

[0029]

[0030] Among them, Χ 1,base (0), ω c,base n 1,base p base , Χ 2,base (0), ω p,base n 2,base m base , σ base The characteristic parameters extracted from 110kV insulating bushings of the same model, batch, and without moisture were used to classify and evaluate the equivalent content level of X wax induced by moisture inside the bushing based on the value of κ. When 0.63212≤κ≤0.76931, the content of X wax caused by moisture was low; when 0.76931<κ≤0.82982, the content of X wax caused by moisture was high; and when 0.82982<κ≤1, the content of X wax caused by moisture was high.

[0031] This invention uses sleeve samples for verification, primarily to clearly reveal the inherent relationship between "moisture development - dielectric response change - increase in X-wax equivalent state" while controlling differences in structural dimensions, material systems, and manufacturing processes. For the objectively existing initial differences between sleeves from different manufacturers and with different service lives, this application has eliminated these differences by introducing non-moisture-affected reference samples of the same model and batch, and by using relative ratios and normalization to process each characteristic parameter. This ensures that the evaluation results reflect the degree of deviation relative to their respective health baseline states, rather than an absolute parameter value itself. Therefore, this method has a theoretical basis for cross-sample transfer. It should be noted that the threshold range is based on the results of embodiments summarized from existing sample data at the application stage, used to illustrate how this method can be applied practically. It does not affect the feasibility and repeatability of the method itself. When applying this method to sleeves from other manufacturers or with different service lives, those skilled in the art can adaptively verify or correct the threshold by following the test procedures, parameter extraction methods, and κ value calculation methods disclosed in this application, combined with the corresponding model reference samples. This is a conventional engineering application of the technical solution of this application to different objects, rather than a change to the inventive concept. Therefore, the universal applicability of the method in this application should not be denied simply because the specification does not exhaustively list data for all manufacturers and all service lifespans of bushings. On the contrary, this application has disclosed complete technical means sufficient for those skilled in the art to implement it, and the construction logic of the formula, the meaning of the parameters, and the evaluation process are all clear, possessing the repeatability required for industrial applications.

[0032] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings, taking into account the effect of moisture, characterized in that... include: Oil-paper insulating sleeve samples under different moisture conditions were prepared; Frequency domain dielectric spectroscopy was performed on the sample to obtain relative dielectric parameter data at different frequencies; Based on the data, a complex relative permittivity expression is constructed, and feature parameters are extracted using the DH dielectric parameter relaxation model; Using the characteristic parameters of a reference sample of the same type, batch, and without moisture as a benchmark, the extracted characteristic parameters were normalized, and the X wax evaluation index was calculated. ; According to the above The value is used to classify and evaluate the equivalent content level of X wax induced by moisture inside the casing.

2. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 1, is characterized in that... The feature parameters extracted using the DH dielectric parameter relaxation model specifically include: Relaxation intensity Χ1(0), characteristic angular frequency ω c Shape parameters n1 and p; Loss peak relaxation intensity Χ2(0), loss peak characteristic angular frequency ω p Loss peak shape parameters n2 and m; And DC conductivity σ; Where, Χ1(0), ω c n1 and p are used to characterize the principal relaxation and low-frequency polarization changes caused by moisture; Χ2(0), ω p σn2 and σm are used to characterize the characteristic changes of the loss peak related to X wax precipitation; σ is used to characterize the degree of conductivity enhancement caused by moisture.

3. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 2, is characterized in that... The X wax evaluation index Calculated using the following formula: In the formula, Χ 1,base (0)、ω c,base n 1,base p base , Χ 2,base (0), ω p,base n 2,base m base σ base These are characteristic parameters extracted from 110kV insulating bushings of the same model, batch, and without moisture. The main factor is moisture. X is the precipitation factor of wax.

4. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 3, is characterized in that... The evaluation indicators The value range is (0,1], when the sample is in the reference state. Approaching 0, with the formation of moisture and X wax, The value increases monotonically and tends to saturate.

5. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 1, is characterized in that... The specific threshold range for the hierarchical assessment is as follows: When 0.63212≤ When the value is ≤0.76931, the content of X wax due to moisture is judged to be at a low level; When 0.76931 < When the value is ≤0.82982, the content of X wax due to moisture is considered to be at a high level; When 0.82982 < When the value is ≤1, the content of X wax due to moisture is considered to be at a high level.

6. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 1, is characterized in that... The frequency range of the frequency domain dielectric spectrum test is from 0.001 Hz to 1000 Hz, specifically including 0.001 Hz, 0.00215 Hz, 0.00464 Hz, 0.01 Hz, 0.0215 Hz, 0.0464 Hz, 0.1 Hz, 0.215 Hz, 0.464 Hz, 1.00 Hz, 2.15 Hz, 4.64 Hz, 10.0 Hz, 21.5 Hz, 46.4 Hz, 100 Hz, 215 Hz, 464 Hz and 1000 Hz.

7. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 1, is characterized in that... The steps for preparing oil-paper insulating sleeve samples under different moisture conditions include: Select at least six sets of brand-new oil-paper insulating sleeve samples of the same model, remove the oil plugs on the oil conservator of each sleeve, place the samples in a constant temperature and humidity chamber, and treat them for different numbers of days under the same temperature and humidity conditions to obtain six sets of samples in different moisture states.

8. The method for evaluating the equivalent wax content of 110kV oil-paper insulating bushings taking into account the effect of moisture, as described in claim 7, is characterized in that... The different number of days are 10 days, 20 days, 30 days, 40 days, 50 days and 60 days.

9. An electronic device, characterized in that, include: processor; And the memory, on which executable instructions are stored; When the executable instructions are executed by the processor, the electronic device performs the method as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, It stores a computer program thereon, which, when executed by a processor, implements the method as described in any one of claims 1 to 8.

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