A method, device and medium for detecting moisture content of insulating paperboard

Abstract

The embodiments of the present application disclose a method, device, and medium for detecting the moisture content of insulating cardboard. The insertion loss characteristics corresponding to the microstrip ring resonator device are obtained through a network analyzer; when the insulating cardboard to be detected is a single layer, the average resonant frequency is obtained based on the information of multiple resonance points in the insertion loss characteristics; the moisture content of the single layer of insulating cardboard to be detected is determined based on the average resonant frequency and a preset moisture content evaluation function; when the insulating cardboard to be detected is two or more layers, the dielectric constant and dielectric loss tangent corresponding to the insulating cardboard to be detected are obtained through a preset microstrip ring resonator dielectric response calculation model and insertion loss characteristics; the dielectric constant and dielectric loss tangent are input into a preset moisture content prediction model to obtain the moisture content corresponding to the two or more layers of insulating cardboard to be detected. Through the above method, the efficiency of insulating cardboard moisture content detection is improved.

Description

Technical Field

[0001] The present application relates to the technical field of insulating paperboard, and in particular to a method, device and medium for detecting the moisture content of insulating paperboard. Background Art

[0002] In renewable energy power systems, oil-paper insulation is widely used in oil-filled equipment such as large power transformers. However, operating oil-paper insulated power equipment, exposed to environmental factors such as moisture, can gradually degrade internally. Over time, insulation aging occurs, leading to a decrease in insulation performance.

[0003] Therefore, moisture is a key factor in the deterioration of transformer insulation board. Dielectric response is a widely used characterization method for evaluating the insulation condition of oil-impregnated board. Time-domain dielectric response testing primarily involves polarization and depolarization current methods, as well as the recovery voltage method. Frequency-domain dielectric response testing involves performing frequency-domain dielectric spectrum testing. However, existing techniques for time-domain dielectric response and frequency-domain dielectric response at lower frequencies (e.g., 0.1 MHz) require lengthy experimental times, resulting in inefficient evaluation of the moisture content of the insulation board. Summary of the Invention

[0004] The embodiments of the present application provide a method, device, and medium for detecting the moisture content of an insulating paperboard, which are used to solve the following technical problem: it is difficult to efficiently determine the moisture content of the insulating paperboard in the existing technology.

[0005] The embodiments of this application adopt the following technical solutions:

[0006] The present application provides a method for detecting moisture content in insulating cardboard. The method comprises: obtaining an insertion loss characteristic corresponding to a microstrip ring resonator device through a network analyzer; wherein a preset thickness of insulating cardboard to be detected is superimposed on the microstrip ring resonator device; the insertion loss characteristic is the insertion loss characteristic corresponding to the insulating cardboard to be detected at a preset microwave frequency band obtained by the network analyzer; when the insulating cardboard to be detected is a single layer, obtaining an average resonant frequency based on information of multiple resonance points in the insertion loss characteristic; determining the moisture content of the single layer of insulating cardboard to be detected based on the average resonant frequency and a preset moisture content evaluation function; when the insulating cardboard to be detected is two or more layers, obtaining a dielectric constant and a dielectric loss tangent value corresponding to the insulating cardboard to be detected by using a preset microstrip ring resonator dielectric response calculation model and the insertion loss characteristic; and inputting the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to the two or more layers of insulating cardboard to be detected.

[0007] This embodiment of the present application uses a microstrip ring resonance method to characterize the dielectric response of insulating paperboard in the microwave frequency range. Since the frequency range of the test in this embodiment is relatively high, the test time required is only a few seconds, making the test more convenient and shortening the test time compared to the traditional FDS test, which takes nearly an hour. Secondly, this embodiment of the present application uses a preset moisture content evaluation function to determine the moisture content of a single layer of insulating paperboard to be tested, and a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested. This allows different moisture content measurement methods to be applied to the different layers of insulating paperboard to ensure accurate moisture content measurement.

[0008] In one implementation of the present application, before obtaining the insertion loss characteristics corresponding to the microstrip ring resonator device using a network analyzer, the method further includes: obtaining, using the network analyzer, a first reference insertion loss characteristic corresponding to the microstrip ring resonator device on which a reference insulating paperboard is placed; wherein different numbers of reference insulating paperboards are superimposed on the microstrip ring resonator device; obtaining reference dielectric constants and reference dielectric loss tangent values ​​corresponding to different numbers of reference insulating paperboards by presetting a dielectric response calculation model of the microstrip ring resonator and the first reference insertion loss characteristic; establishing a reference dielectric constant variation curve based on the number of reference insulating paperboards and the reference dielectric constant; establishing a dielectric loss tangent variation curve based on the number of reference insulating paperboards and the dielectric loss tangent values; determining the number of reference insulating paperboards in a steady state based on the corresponding variation trends of the reference dielectric constant variation curve and the dielectric loss tangent variation curve; and determining a preset thickness of the insulating paperboard to be tested based on the number of reference insulating paperboards and the thickness of the reference insulating paperboards in the steady state, so as to measure the moisture content of the insulating paperboard to be tested of the preset thickness.

[0009] In one implementation of the present application, when the insulating cardboard to be tested is a single layer, an average resonant frequency is obtained based on information about multiple resonance points in the insertion loss characteristics. The method specifically includes: determining the total number and order of the multiple resonance points; determining the resonant frequencies corresponding to the multiple resonance points; determining the ratios between the resonant frequencies corresponding to the multiple resonance points and the order of the resonance points; summing the ratios corresponding to the multiple resonance points, and calculating the ratio of the summed calculation result to the total number of the multiple resonance points to obtain the average resonant frequency corresponding to the insulating cardboard to be tested.

[0010] In one implementation of the present application, the moisture content of the insulating paperboard to be tested in a single-layer case is determined based on the average value of the resonant frequency and a preset moisture content evaluation function. Specifically, the method includes: performing multiple polynomial fitting on the average value of the resonant frequency based on the preset moisture content evaluation function; and using the fitting results as the moisture content of the insulating paperboard to be tested in the single-layer case.

[0011] In one implementation of the present application, before obtaining the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested by presetting the dielectric response calculation model and insertion loss characteristics of the microstrip ring resonator, the method also includes: obtaining a reference resonant frequency corresponding to the insulating cardboard sample through a network analyzer; constructing an equivalent dielectric constant calculation function based on the number of resonances of the reference resonant frequency, the average radius of the copper ring in the microstrip ring resonator device, and the speed of light; determining the structural parameters corresponding to the microstrip ring resonator device based on the substrate layer height, copper ring and microstrip line width corresponding to the microstrip ring resonator device; determining the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers respectively based on the structural parameters corresponding to the microstrip ring resonator device; obtaining the quality factor corresponding to the microstrip ring resonator device, and constructing a dielectric loss tangent value calculation function based on the quality factor; and constructing a preset microstrip ring resonator dielectric response calculation model based on the equivalent dielectric constant calculation function, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers respectively, and the dielectric loss tangent value calculation function.

[0012] In one implementation of the present application, a quality factor corresponding to a microstrip ring resonator device is obtained, and a dielectric loss tangent calculation function is constructed based on the quality factor, specifically including: determining the quality factor of the insulating cardboard sample when loaded and the quality factor when unloaded based on the second reference loss characteristic corresponding to the insulating cardboard sample; determining the equivalent dielectric constant calculation function and the equivalent dielectric loss tangent calculation function corresponding to the microstrip ring resonator device of a single-layer dielectric based on the substrate dielectric constant, the substrate layer height corresponding to the microstrip ring resonator device, and the width of the copper ring and the microstrip line; constructing a dielectric loss tangent calculation function based on the quality factor when loaded and the quality factor when unloaded, the equivalent dielectric constant calculation function and the equivalent dielectric loss tangent calculation function corresponding to the microstrip ring resonator device of a single-layer dielectric, the equivalent dielectric loss tangent calculation function, and the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers.

[0013] In one implementation of the present application, before inputting the dielectric constant and the dielectric loss tangent into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating cardboard to be tested, the method further includes: using the dielectric constant and the dielectric loss tangent corresponding to multiple insulating cardboard samples as input, and using the equivalent moisture content and the degree of unevenness corresponding to the multiple insulating cardboard samples as output, to train a preset neural network model to obtain the preset moisture content prediction model.

[0014] In one implementation of the present application, before determining the moisture content of the insulating paperboard to be tested in a single-layer case based on the average value of the resonant frequency and a preset moisture content evaluation function, the method further includes: determining reference moisture contents corresponding to multiple single-layer insulating paperboard samples based on the preset moisture content evaluation function; constructing a reference moisture content evaluation curve based on the multiple reference moisture contents; and performing confidence calculation based on the reference moisture content evaluation curve. If the confidence falls within a preset confidence interval, determining that the preset moisture content evaluation function is correct.

[0015] An embodiment of the present application provides an insulating cardboard moisture content detection device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to: obtain an insertion loss characteristic corresponding to a microstrip ring resonator device through a network analyzer; wherein a predetermined thickness of insulating cardboard to be tested is superimposed on the microstrip ring resonator device; and wherein the insertion loss characteristic is the insertion loss characteristic corresponding to the insulating cardboard to be tested at a predetermined microwave frequency band, obtained by the network analyzer; when the insulating cardboard to be tested is a single layer, obtaining an average resonant frequency based on information of multiple resonance points in the insertion loss characteristic; determining the moisture content of the single layer of insulating cardboard to be tested based on the average resonant frequency and a preset moisture content evaluation function; and when the insulating cardboard to be tested is two or more layers, obtaining a dielectric constant and a dielectric loss tangent value corresponding to the insulating cardboard to be tested based on a preset microstrip ring resonator dielectric response calculation model and the insertion loss characteristic; and inputting the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to the two or more layers of insulating cardboard to be tested.

[0016] An embodiment of the present application provides a non-volatile computer storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured to: obtain, using a network analyzer, an insertion loss characteristic corresponding to a microstrip ring resonator device; wherein a predetermined thickness of insulating cardboard to be tested is superimposed on the microstrip ring resonator device; the insertion loss characteristic is the insertion loss characteristic corresponding to the insulating cardboard to be tested at a predetermined microwave frequency band, obtained by the network analyzer; if the insulating cardboard to be tested is a single layer, obtain an average resonant frequency based on information about multiple resonance points in the insertion loss characteristic; determine the moisture content of the single layer of insulating cardboard to be tested based on the average resonant frequency and a preset moisture content evaluation function; if the insulating cardboard to be tested is two or more layers, obtain a dielectric constant and a dielectric loss tangent value corresponding to the insulating cardboard to be tested using a preset microstrip ring resonator dielectric response calculation model and the insertion loss characteristic; and input the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to the two or more layers of insulating cardboard to be tested.

[0017] At least one of the above-mentioned technical solutions employed in the embodiments of the present application can achieve the following beneficial effects: The embodiments of the present application use a microstrip ring resonance method to characterize the dielectric response of insulating paperboard in the microwave frequency range. The frequency range of the test in the embodiments of the present application is relatively high, so the test time required is only a few seconds, making the test more convenient and shortening the test time compared to the traditional FDS test, which takes nearly an hour. Secondly, the embodiments of the present application use a preset moisture content evaluation function to determine the moisture content of a single layer of insulating paperboard to be tested, and a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested. This allows different moisture content measurement methods to be applied to the different layers of insulating paperboard to ensure the accuracy of the moisture content measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments described in the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. In the drawings:

[0019] Figure 1 A flow chart of a method for detecting moisture content in insulating paperboard provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the microstrip ring resonance experiment arrangement provided in an embodiment of the present application;

[0021] Figure 3 Schematic diagram of a microstrip ring resonator with stacked insulating paper provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of a moisture content evaluation curve for insulating paperboard provided in an embodiment of the present application;

[0023] Figure 5 This is a structural schematic diagram of an insulating paperboard moisture content detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The embodiments of the present application provide a method, device, and medium for detecting the moisture content of insulating paperboard.

[0025] In order to enable those skilled in the art to better understand the technical solutions in this application, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0026] In renewable energy power systems, oil-paper insulation is widely used in oil-filled equipment such as large power transformers. However, operating oil-paper insulated power equipment, exposed to environmental factors such as moisture, can gradually degrade internally. Over time, insulation aging occurs, leading to a decrease in insulation performance.

[0027] Therefore, moisture is a key factor in the deterioration of transformer insulation board. Dielectric response is a widely used characterization method for evaluating the insulation condition of oil-impregnated board. Time-domain dielectric response testing primarily involves polarization and depolarization current methods, as well as the recovery voltage method. Frequency-domain dielectric response testing involves performing frequency-domain dielectric spectrum testing. However, existing techniques for time-domain dielectric response and frequency-domain dielectric response at lower frequencies (e.g., 0.1 MHz) require lengthy experimental times, resulting in inefficient evaluation of the moisture content of the insulation board.

[0028] To address the above-mentioned problems, the embodiments of the present application provide a method, device, and medium for detecting the moisture content of insulating cardboard. The dielectric response of the insulating cardboard in the microwave frequency band is characterized by the microstrip ring resonance method, and the frequency range of the test in the embodiments of the present application is relatively high, so the required time is only a few seconds, and the test is convenient. Compared with the traditional FDS test that takes nearly an hour, the test time is shortened. Secondly, the embodiments of the present application determine the moisture content of a single layer of insulating cardboard to be tested by presetting a moisture content evaluation function, and obtain the moisture content corresponding to two or more layers of insulating cardboard to be tested by presetting a moisture content prediction model. Therefore, according to the different number of layers of insulating cardboard to be tested, different methods are applied to measure the moisture content to ensure the accuracy of the moisture content measurement.

[0029] The technical solutions proposed in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0030] Figure 1 This is a flow chart of a method for detecting moisture content in insulating paperboard provided in an embodiment of the present application. Figure 1 As shown, the method for detecting the moisture content of insulating paperboard includes the following steps:

[0031] S101. Obtaining insertion loss characteristics corresponding to a microstrip ring resonator device using a network analyzer. The microstrip ring resonator device is overlaid with a predetermined thickness of insulating cardboard to be tested; the insertion loss characteristics are the insertion loss characteristics corresponding to the insulating cardboard to be tested at a predetermined microwave frequency band, obtained by the network analyzer.

[0032] In one embodiment of the present application, first, an insulating paperboard moisture content detection device is constructed. Figure 2 The schematic diagram of the microstrip ring resonance experiment arrangement provided in the embodiment of the present application is as follows: Figure 2 As shown in the figure, the insulation paperboard moisture content detection equipment mainly consists of a network analyzer (Pico VNA), a PC, a signal transmission line, a special test cable, a microstrip ring resonator device, etc.

[0033] Specifically, the substrate selected in the embodiment of the present application is NX9320 high-frequency plate produced by Nelco, with a layer height h1 of 0.762 mm and a relative dielectric constant ε r It is 3.2±0.4, and the dielectric loss tangent tanδ is 0.0024. Two copper microstrip lines and a copper ring are attached to the base high-frequency plate. The characteristic impedance Z0 is 50Ω, the copper thickness is 0.5oz, the width w of the copper ring and the microstrip line is 1.85mm, the inner radius of the copper ring is 25mm, the outer radius is 26.85mm, and the coupling air gap between the copper ring and the microstrip line is 0.4mm. Above the substrate is a layer of known thickness such as insulating cardboard. Two SMA interfaces are designed at both ends of the resonator for connecting to a network analyzer for testing. The embodiment of the present application uses the network analyzer PicoVNA 106 produced by Pico, with a test bandwidth of 300kHz~6GHz. By testing the S of the entire resonant device 21 The parameters are the insertion loss characteristics, find the resonance point and derive its dielectric parameters.

[0034] In one embodiment of the present application, a reference resonant frequency corresponding to an insulating cardboard sample is obtained by a network analyzer. Based on the resonance number of the reference resonant frequency, the average radius of the copper ring in the microstrip ring resonator device, and the speed of light, an equivalent dielectric constant calculation function is constructed. Based on the substrate layer height, copper ring and microstrip line width corresponding to the microstrip ring resonator device, the structural parameters corresponding to the microstrip ring resonator device are determined. According to the structural parameters corresponding to the microstrip ring resonator device, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers is determined. The quality factor corresponding to the microstrip ring resonator device is obtained, and a dielectric loss tangent value calculation function is constructed based on the quality factor. Based on the equivalent dielectric constant calculation function, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers, and the dielectric loss tangent value calculation function, a preset microstrip ring resonator dielectric response calculation model is constructed.

[0035] Specifically, the embodiment of the present application pre-builds a preset microstrip ring resonator dielectric response calculation model to calculate the dielectric constant and dielectric loss tangent value corresponding to the insulating paperboard.

[0036] Furthermore, the dielectric constant ε r Calculation:

[0037] Resonant frequency f res The equivalent dielectric constant ε of the entire device r_eff The relationship is:

[0038]

[0039] Right now

[0040] ε r_eff =[nc / (2πr mean f res )] 2 (2)

[0041] Where n is the number of resonances; c is the speed of light; and rmean is the average radius of the copper ring, which is calculated to be 25.925 mm.

[0042] Equivalent dielectric constant ε r_eff The dielectric constants ε of the upper and lower layers r_pb , ε r_sub The relationship between them is:

[0043]

[0044] Right now

[0045]

[0046] Where, the subscripts eff, pb, and sub represent the equivalent parameter, insulation board parameter, and substrate parameter, respectively. q1 and q2 are the structural parameters of the microstrip ring device:

[0047] When w / h1≥1,

[0048]

[0049]

[0050] Where w eff and v eff are the equivalent feeder width and phase parameters, respectively, and the calculation formula is as follows:

[0051]

[0052]

[0053] The resonator designed in the embodiment of the present application has w / h1=1.85 / 0.762>1, so equations (5) to (8) are used to calculate the structural parameters q1 and q2.

[0054] In one embodiment of the present application, the quality factor of the insulating cardboard sample under load and under no load is determined based on the second reference loss characteristic corresponding to the insulating cardboard sample. The equivalent dielectric constant calculation function and the equivalent dielectric loss tangent calculation function corresponding to the single-layer dielectric microstrip ring resonator device are determined based on the substrate dielectric constant, the substrate layer height corresponding to the microstrip ring resonator device, and the copper ring and microstrip line widths. A dielectric loss tangent value calculation function is constructed based on the quality factor under load and under no load, the equivalent dielectric constant calculation function and the equivalent dielectric loss tangent calculation function, the equivalent dielectric loss tangent calculation function, and the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers.

[0055] Specifically, in the embodiment of the present application, the calculation of the dielectric loss tangent value includes:

[0056] The dielectric loss tangent tanδ is related to the quality factor Q of the resonant device. The quality factor Q can be characterized by the insertion loss (IL) of the resonator, IL = 20log (|S 21 |). Quality factor Q under load l and the quality factor Q at no load u Satisfies the following relationship:

[0057]

[0058]

[0059] Q u Quality factor Q corresponding to conductivity loss, dielectric loss, and radiation loss c , Q d , Q r The relationship is as follows:

[0060]

[0061] Generally speaking, the equivalent dielectric loss tangent of the resonant device is related to Q d Related, satisfying: tanδ eff =1 / Q d Before and after adding the sample, the conductivity loss and radiation loss of the resonant device remain basically unchanged, and the quality factor Q c , Q r The changes are negligible, so:

[0062]

[0063] The subscript “0” indicates the parameters before adding the sample.

[0064] In the microstrip model of a single-layer medium (i.e., without adding a sample), the equivalent dielectric constant and substrate dielectric constant, the equivalent dielectric loss tangent and substrate dielectric loss tangent respectively satisfy:

[0065]

[0066]

[0067] Let F = (1 + 10h1 / w) 1 / 2 , tanδ eff0 =p sub0 tanδ sub ,but

[0068]

[0069] In the microstrip model of N-layer dielectrics, the equivalent dielectric loss tangent and the dielectric parameters of each layer of dielectric satisfy the following relationship:

[0070]

[0071] In terms of the double-layer medium model,

[0072]

[0073] Combined with formula (3),

[0074]

[0075]

[0076] tanδ eff =p sub tanδ sub +p pb tanδ pb (20)

[0077] Combining equations (12) to (20), we get

[0078]

[0079] In summary, equations (1) to (21) constitute the dielectric response calculation model of the preset microstrip ring resonator.

[0080] In one embodiment of the present application, a network analyzer is used to obtain a first reference insertion loss characteristic corresponding to a microstrip ring resonator device on which reference insulating paper sheets are placed. Different numbers of reference insulating paper sheets are superimposed on the microstrip ring resonator device. By presetting a dielectric response calculation model for the microstrip ring resonator and the first reference insertion loss characteristic, reference dielectric constants and reference dielectric loss tangent values ​​corresponding to different numbers of reference insulating paper sheets are obtained. A reference dielectric constant variation curve is established based on the number of reference insulating paper sheets and the reference dielectric constant. A dielectric loss tangent variation curve is established based on the number of reference insulating paper sheets and the dielectric loss tangent values. Based on the trends of the reference dielectric constant variation curve and the dielectric loss tangent variation curve, the number of reference insulating paper sheets in a steady state is determined. Based on the number of reference insulating paper sheets and the thickness of the reference insulating paper sheets in the steady state, a preset thickness of the insulating paper sheet to be tested is determined, thereby measuring the moisture content of the insulating paper sheet to be tested of the preset thickness.

[0081] Specifically, Figure 3 Schematic diagram of a microstrip ring resonator with superimposed insulating paper provided in an embodiment of the present application. The embodiment of the present application uses a transparent acrylic clip for clamping in order to make the insulating paper and the resonator fit more tightly. Experimental comparison shows that the clamp has almost no effect on the test results. The reference insertion loss characteristics corresponding to the microstrip ring resonator device are obtained by using a network analyzer. From the insertion loss characteristics of the resonant device measured by different numbers of layers of insulating paper, it can be seen that there are five resonance points in the frequency band of 1 to 6 GHz. It should be noted that the embodiment of the present application measures the moisture content of the insulating paperboard in the frequency band of 1 to 6 GHz. Based on the preset microstrip ring resonator dielectric response calculation model, a curve showing the dielectric constant and dielectric loss tangent of the insulating paper at each resonance point changing with the number of layers is obtained.

[0082] Furthermore, it can be seen from the experiment that the number of layers has a certain influence on the calculation results of the dielectric constant and the dielectric loss tangent. The dielectric constant first rises and then falls as the number of insulating paper layers increases, and then tends to be stable. The dielectric loss tangent shows a downward trend as the number of insulating paper layers increases, and eventually tends to be stable. According to dielectric theory, the dielectric properties of the same insulating material should not change with changes in its shape parameters such as thickness. Combined with experiments, it can be seen that when the number of insulating paper layers is more than 8 layers, that is, when the thickness of the upper dielectric layer of the resonator is above 0.125×8=1mm, the dielectric properties obtained by the analytical model are accurate and reliable. Therefore, the preferred value of the upper dielectric thickness tested using the resonator designed in the embodiment of the application is above 1mm.

[0083] S102 : When the insulating paperboard to be tested is a single layer, obtain an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics.

[0084] In one embodiment of the present application, the total number and order of multiple resonance points are determined, as well as the resonant frequencies corresponding to the multiple resonance points. The ratios between the resonant frequencies corresponding to the multiple resonance points and the order of the resonance points are determined. The ratios corresponding to the multiple resonance points are summed, and the summed result is then compared to the total number of resonance points to obtain an average resonant frequency corresponding to the insulating paperboard to be tested.

[0085] Specifically, based on the function

[0086]

[0087] Get the average value of the resonant frequency corresponding to the insulation cardboard to be tested. Where n represents the total number of resonance points, i represents the order of the resonance points, and f res ,i represents the resonant frequency of the i-th resonance point.

[0088] S103 : Determine the moisture content of the insulating paperboard to be tested in a single-layer case based on the average value of the resonant frequency and a preset moisture content evaluation function.

[0089] The embodiment of the present application is based on the moisture content of the uniformly damp single-layer paperboard and the average resonant frequency converted to the fundamental frequency by the five resonant points. The relationship between the three polynomials is fitted to form Figure 4 The moisture assessment curve shown has a goodness of fit of 0.9869.

[0090] In one embodiment of the present application, reference moisture contents corresponding to multiple single-layer insulation paperboard samples are determined based on a preset moisture content evaluation function. A reference moisture content evaluation curve is constructed based on the multiple reference moisture contents. A confidence level is calculated based on the reference moisture content evaluation curve, and if the confidence level falls within a preset confidence level range, the preset moisture content evaluation function is determined to be correct.

[0091] Specifically, in order to determine whether the moisture content measured by the preset moisture content evaluation function is correct, the present embodiment of the invention pre-prepared insulation cardboard samples with the same specifications and moisture contents of 2.11%, 3.23%, and 4.25%, respectively, and conducted microstrip ring resonance tests to calculate the corresponding average resonant frequency. Figure 4 This is a schematic diagram of the moisture content evaluation curve of the insulating paperboard provided in the embodiment of the present application. Substitute the calculated average resonant frequency into Figure 4 The evaluation equation in was verified and the evaluation results were good, all falling within the 95% confidence interval. Detailed evaluation data are shown in Table 1.

[0092]

[0093] Table 1

[0094] Therefore, the moisture content evaluation equation obtained in this section is suitable for evaluating the moisture degree of insulating cardboard with a moisture content below 7% when tested using the microstrip ring resonance method.

[0095] In one embodiment of the present application, based on a preset moisture content evaluation function, the average value of the resonant frequency is subjected to multiple polynomial fittings, and the fitting results are used as the moisture content of the insulating paperboard to be tested in the case of a single layer.

[0096] Specifically, when the insulating cardboard to be tested is a single layer, the resonance frequency corresponding to the insulating cardboard to be tested is obtained by a network analyzer. Based on the above function (22), the average resonance frequency corresponding to the insulating cardboard to be tested is obtained. Substitute the average resonance frequency into Figure 4 The preset moisture content evaluation function in can be used to obtain the moisture content of the insulating cardboard to be tested by calculating the y value.

[0097] S104. When the insulating cardboard to be tested has two or more layers, obtain the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested by presetting the dielectric response calculation model and insertion loss characteristics of the microstrip ring resonator.

[0098] In one embodiment of the present application, when the insulating cardboard to be tested consists of two or more layers, the multiple layers are affixed to a microstrip ring resonator device, and a network analyzer is used to obtain the corresponding insertion loss characteristics. Using a pre-set microstrip ring resonator dielectric response calculation model, the obtained insertion loss characteristics are calculated to obtain the dielectric constant and dielectric loss tangent corresponding to the multiple layers of insulating cardboard to be tested.

[0099] S105: Input the dielectric constant and the dielectric loss tangent into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested.

[0100] In one embodiment of the present application, a neural network model is trained using multiple insulating cardboard samples to obtain a preset moisture content prediction model. The training process involves using the dielectric constant and dielectric loss tangent corresponding to the multiple insulating cardboard samples as input, and the equivalent moisture content and degree of nonuniformity corresponding to the multiple insulating cardboard samples as output. The preset neural network model is trained to obtain the preset moisture content prediction model. The equivalent moisture content in this embodiment is the average moisture content of the multiple insulating cardboard samples, and the degree of nonuniformity refers to the number of insulating cardboard samples.

[0101] Furthermore, the dielectric constant and dielectric loss tangent corresponding to the current multiple layers of insulating cardboard to be tested, obtained through the preset microstrip ring resonator dielectric response calculation model, are input into the preset moisture content prediction model to obtain the equivalent moisture content and unevenness corresponding to the current multiple layers of insulating cardboard to be tested.

[0102] Figure 5 This is a schematic diagram of the structure of an insulation paperboard moisture content detection device provided in an embodiment of the present application. Figure 5 As shown, the insulation paperboard moisture content detection equipment includes:

[0103] at least one processor; and,

[0104] a memory communicatively connected to the at least one processor; wherein,

[0105] The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to:

[0106] Obtaining insertion loss characteristics corresponding to a microstrip ring resonator device using a network analyzer; wherein an insulating cardboard to be tested is superimposed on the microstrip ring resonator device with a preset thickness; the insertion loss characteristics are insertion loss characteristics corresponding to the insulating cardboard to be tested at a preset microwave frequency band obtained by the network analyzer;

[0107] When the insulating paperboard to be tested is a single layer, obtaining an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics;

[0108] Determining the moisture content of a single layer of insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function;

[0109] When the insulating cardboard to be tested has two or more layers, the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested are obtained by presetting the dielectric response calculation model of the microstrip ring resonator and the insertion loss characteristics;

[0110] The dielectric constant and the dielectric loss tangent value are input into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested.

[0111] The present application also provides a non-volatile computer storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured as follows:

[0112] Obtaining an insertion loss characteristic corresponding to a microstrip ring resonator device using a network analyzer; wherein an insulating cardboard to be tested having a preset thickness is superimposed on the microstrip ring resonator device, and the insertion loss characteristic is the insertion loss characteristic corresponding to the insulating cardboard to be tested at a preset microwave frequency band obtained by the network analyzer;

[0113] When the insulating paperboard to be tested is a single layer, obtaining an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics;

[0114] Determining the moisture content of the insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function;

[0115] When the insulating cardboard to be tested has two or more layers, the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested are obtained by presetting the dielectric response calculation model of the microstrip ring resonator and the insertion loss characteristics;

[0116] The dielectric constant and the dielectric loss tangent value are input into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested.

[0117] The various embodiments in this application are described in a progressive manner. Similar portions between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the device, apparatus, and non-volatile computer storage medium embodiments are generally similar to the method embodiments, so their descriptions are relatively simple. For relevant portions, refer to the descriptions of the method embodiments.

[0118] The foregoing description describes specific embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in an order different from that described in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order shown or the sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0119] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the embodiments of the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for detecting moisture content of insulating paperboard, characterized in that: The method comprises: Obtaining insertion loss characteristics corresponding to a microstrip ring resonator device using a network analyzer; wherein an insulating cardboard to be tested is superimposed on the microstrip ring resonator device with a preset thickness; the insertion loss characteristics are insertion loss characteristics corresponding to the insulating cardboard to be tested at a preset microwave frequency band obtained by the network analyzer; When the insulating paperboard to be tested is a single layer, obtaining an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics; Determining the moisture content of a single layer of insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function; Obtain the reference resonant frequency corresponding to the insulation cardboard sample through a network analyzer; Constructing an equivalent dielectric constant calculation function based on the resonance number of the reference resonant frequency, the average radius of the copper ring in the microstrip ring resonator device, and the speed of light; Determining structural parameters corresponding to the microstrip ring resonator device based on the substrate height, copper ring and microstrip line widths corresponding to the microstrip ring resonator device; Determining, based on the structural parameters corresponding to the microstrip ring resonator device, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers; Obtaining a quality factor corresponding to the microstrip ring resonator device, and constructing a dielectric loss tangent value calculation function based on the quality factor; Based on the equivalent dielectric constant calculation function, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers, and the dielectric loss tangent value calculation function, a preset microstrip ring resonator dielectric response calculation model is constructed; When the insulating cardboard to be tested has two or more layers, the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested are obtained by presetting the dielectric response calculation model of the microstrip ring resonator and the insertion loss characteristics; Input the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested; When the insulating paperboard to be tested is a single layer, obtaining the average resonant frequency based on information of multiple resonance points in the insertion loss characteristics specifically includes: determining the total number and order of the plurality of resonance points; and Determining the resonant frequencies corresponding to the plurality of resonant points respectively; Determining the ratios between the resonant frequencies corresponding to the plurality of resonant points and the order of the resonant points; The ratios corresponding to the multiple resonance points are summed and calculated, and the summation result is ratio-calculated with the total number of the multiple resonance points to obtain an average value of the resonance frequency corresponding to the insulating paperboard to be tested.

2. The method for detecting moisture content of insulating paperboard according to claim 1, characterized in that: Before obtaining the insertion loss characteristics corresponding to the microstrip ring resonator device through a network analyzer, the method further includes: Obtaining a first reference insertion loss characteristic corresponding to a microstrip ring resonator device on which a reference insulating cardboard is placed using a network analyzer; wherein different numbers of reference insulating cardboards are stacked on the microstrip ring resonator device; By presetting the dielectric response calculation model of the microstrip ring resonator and the first reference insertion loss characteristic, the reference dielectric constant and the reference dielectric loss tangent corresponding to different numbers of reference insulating paperboards are obtained; Establishing a reference dielectric constant variation curve graph based on the quantity of the reference insulating paperboards and the reference dielectric constant; Establishing a dielectric loss tangent value variation curve graph based on the number of the reference insulating paperboards and the dielectric loss tangent value; Determining the quantity of the reference insulating paperboards in a stable state based on the change trends of the reference dielectric constant change curve and the dielectric loss tangent change curve respectively corresponding to each other; Based on the quantity and thickness of the reference insulating paper sheets in the steady state, a preset thickness of the insulating paper sheet to be tested is determined to measure the moisture content of the insulating paper sheet to be tested with the preset thickness.

3. The method for detecting moisture content of insulating paperboard according to claim 1, characterized in that: The determining of the moisture content of the single layer of insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function specifically includes: Substituting the average value of the resonant frequency into the preset water content evaluation function; The obtained value is used as the moisture content of the single layer of insulating paperboard to be tested.

4. The method for detecting moisture content of insulating paperboard according to claim 1, characterized in that: The obtaining of the quality factor corresponding to the microstrip ring resonator device and constructing the dielectric loss tangent value calculation function based on the quality factor specifically includes: Determining a quality factor when loaded and a quality factor when not loaded corresponding to the insulating paperboard sample based on a second reference loss characteristic corresponding to the insulating paperboard sample; Determine an equivalent dielectric constant calculation function and an equivalent dielectric loss tangent calculation function corresponding to a single-layer dielectric microstrip ring resonator device based on the substrate dielectric constant, the substrate layer height corresponding to the microstrip ring resonator device, and the width of the copper ring and the microstrip line; Based on the quality factor when loaded and the quality factor when unloaded, the equivalent dielectric constant calculation function and the equivalent dielectric loss tangent calculation function corresponding to the single-layer dielectric microstrip ring resonator device, and the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers, the dielectric loss tangent value calculation function is constructed.

5. The method for detecting moisture content of insulating paperboard according to claim 1, characterized in that: Before inputting the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested, the method further includes: The dielectric constant and dielectric loss tangent value corresponding to multiple insulating cardboard samples are used as input, and the equivalent moisture content and unevenness degree corresponding to the multiple insulating cardboard samples are used as output. The preset neural network model is trained to obtain the preset moisture content prediction model.

6. The method for detecting moisture content of insulating paperboard according to claim 1, characterized in that: Before determining the moisture content of the insulating paperboard to be tested in a single-layer case based on the average value of the resonant frequency and a preset moisture content evaluation function, the method further includes: Determining reference moisture contents corresponding to a plurality of single-layer insulation paperboard samples based on the preset moisture content evaluation function; constructing a reference moisture content assessment curve based on a plurality of said reference moisture contents; A confidence calculation is performed based on the reference moisture content evaluation curve, and when the confidence falls within a preset confidence interval, it is determined that the preset moisture content evaluation function is correct.

7. An insulating paperboard moisture content detection device, comprising: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to: Obtaining insertion loss characteristics corresponding to a microstrip ring resonator device using a network analyzer; wherein an insulating cardboard to be tested is superimposed on the microstrip ring resonator device with a preset thickness; the insertion loss characteristics are insertion loss characteristics corresponding to the insulating cardboard to be tested at a preset microwave frequency band obtained by the network analyzer; When the insulating paperboard to be tested is a single layer, obtaining an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics; Determining the moisture content of a single layer of insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function; Obtain the reference resonant frequency corresponding to the insulation cardboard sample through a network analyzer; Constructing an equivalent dielectric constant calculation function based on the resonance number of the reference resonant frequency, the average radius of the copper ring in the microstrip ring resonator device, and the speed of light; Determining structural parameters corresponding to the microstrip ring resonator device based on the substrate height, copper ring and microstrip line widths corresponding to the microstrip ring resonator device; Determining, based on the structural parameters corresponding to the microstrip ring resonator device, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers; Obtaining a quality factor corresponding to the microstrip ring resonator device, and constructing a dielectric loss tangent value calculation function based on the quality factor; Based on the equivalent dielectric constant calculation function, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers, and the dielectric loss tangent value calculation function, a preset microstrip ring resonator dielectric response calculation model is constructed; When the insulating cardboard to be tested has two or more layers, the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested are obtained by presetting the dielectric response calculation model of the microstrip ring resonator and the insertion loss characteristics; Input the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested; When the insulating paperboard to be tested is a single layer, obtaining the average resonant frequency based on information of multiple resonance points in the insertion loss characteristics specifically includes: determining the total number and order of the plurality of resonance points; and Determining the resonant frequencies corresponding to the plurality of resonant points respectively; Determining the ratios between the resonant frequencies corresponding to the plurality of resonant points and the order of the resonant points; The ratios corresponding to the multiple resonance points are summed and calculated, and the summation result is ratio-calculated with the total number of the multiple resonance points to obtain an average value of the resonance frequency corresponding to the insulating paperboard to be tested.

8. A non-volatile computer storage medium storing computer-executable instructions, wherein the computer-executable instructions are configured to: The insertion loss characteristics of the microstrip ring resonator device are obtained by a network analyzer; The microstrip ring resonator device is stacked with an insulating cardboard to be tested of a preset thickness; the insertion loss characteristic is the insertion loss characteristic corresponding to the insulating cardboard to be tested under a preset microwave frequency band obtained by the network analyzer; When the insulating paperboard to be tested is a single layer, obtaining an average value of the resonant frequency based on information of multiple resonance points in the insertion loss characteristics; Determining the moisture content of a single layer of insulating paperboard to be tested based on the average value of the resonant frequency and a preset moisture content evaluation function; Obtain the reference resonant frequency corresponding to the insulation cardboard sample through a network analyzer; Constructing an equivalent dielectric constant calculation function based on the resonance number of the reference resonant frequency, the average radius of the copper ring in the microstrip ring resonator device, and the speed of light; Determining structural parameters corresponding to the microstrip ring resonator device based on the substrate height, copper ring and microstrip line widths corresponding to the microstrip ring resonator device; Determining, based on the structural parameters corresponding to the microstrip ring resonator device, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers; Obtaining a quality factor corresponding to the microstrip ring resonator device, and constructing a dielectric loss tangent value calculation function based on the quality factor; Based on the equivalent dielectric constant calculation function, the relationship function between the equivalent dielectric constant and the dielectric constants of the upper and lower layers, and the dielectric loss tangent value calculation function, a preset microstrip ring resonator dielectric response calculation model is constructed; When the insulating cardboard to be tested has two or more layers, the dielectric constant and dielectric loss tangent value corresponding to the insulating cardboard to be tested are obtained by presetting the dielectric response calculation model of the microstrip ring resonator and the insertion loss characteristics; Input the dielectric constant and the dielectric loss tangent value into a preset moisture content prediction model to obtain the moisture content corresponding to two or more layers of insulating paperboard to be tested; When the insulating paperboard to be tested is a single layer, obtaining the average resonant frequency based on information of multiple resonance points in the insertion loss characteristics specifically includes: determining the total number and order of the plurality of resonance points; and Determining the resonant frequencies corresponding to the plurality of resonant points respectively; Determining the ratios between the resonant frequencies corresponding to the plurality of resonant points and the order of the resonant points; The ratios corresponding to the multiple resonance points are summed and calculated, and the summation result is ratio-calculated with the total number of the multiple resonance points to obtain an average value of the resonance frequency corresponding to the insulating paperboard to be tested.

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