A method and device for identifying polarization equivalent circuit parameters of oil-paper insulation equipment

Abstract

The present invention provides a method and device for identifying parameters of the polarization equivalent circuit of oil-paper insulation equipment. The method comprises characterizing the insulation system of the oil-paper insulation equipment using an extended Debye equivalent circuit model to obtain an equivalent circuit based on the extended Debye model; obtaining a measured complex capacitance real part spectrum line, removing the geometric capacitance from the measured complex capacitance real part spectrum line to obtain a polarization complex capacitance real part spectrum line; differentiating the polarization complex capacitance real part of the polarization equivalent circuit; analyzing and processing the polarization complex capacitance real part quadratic molecular spectrum line function based on the peak point coordinates of each sub-spectral line in the actual coordinate axis; and selecting the peak point coordinates of the polarization complex capacitance real part quadratic differential spectrum line for identification processing to generate a parameter identification result. This method identifies polarization equivalent circuit parameters using unique and accurate peak point coordinates, rather than randomly selecting two points at the end of a sub-spectral line, effectively ensuring the uniqueness and accuracy of the parameter identification result.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-paper insulation equipment, and in particular to a method and device for identifying polarization equivalent circuit parameters of oil-paper insulation equipment. Background Art

[0002] The extended Debye equivalent circuit of the insulation system of oil-paper insulated equipment is an important means to analyze the aging state of the insulation medium inside the equipment, which mainly includes the geometric equivalent circuit and the polarization equivalent circuit. g , geometric capacitance C g It is mainly determined by the internal structure of the device and can be directly measured by instruments. Therefore, the key to identifying the parameters of the extended Debye equivalent circuit lies in the determination of the polarization equivalent circuit parameters. Currently, there are two main methods for using differential decomposition to identify polarization equivalent circuit parameters. One is to perform differential decomposition on the time domain dielectric spectrum (mainly referring to the recovery voltage spectrum line and the polarization-depolarization current spectrum line, the same below), taking two points at the end of the differential spectrum line and then successively decomposing each sub-spectrum line, and solving for each polarization branch parameter; the other is to perform a differential decomposition on the frequency domain dielectric spectrum, successively decomposing each sub-spectrum line through the coordinates of each peak point of the differential spectrum line, and solving for each polarization branch parameter.

[0003] Among them, the number of polarization branches obtained by differential decomposition of the recovery voltage spectrum and the polarization-depolarization current spectrum (i.e., time-domain dielectric spectrum) can reasonably change according to the different degrees of equipment aging, but there are the following main problems: First, the time-domain dielectric spectrum is a single spectrum line obtained at a certain charge and discharge time, while the time-domain dielectric spectrum at different charge and discharge times reflects the dielectric properties of different types of insulating media; the time-domain dielectric spectrum measured at a single time cannot fully reflect the dielectric response of the insulating medium as a whole, and the time-domain dielectric spectrum obtained at what charge and discharge time can fully and effectively reflect the dielectric condition of the insulating medium as a whole has not yet been studied. Second, the time-domain differential spectrum line decomposition solves the parameters of each sub-spectral line at a random point at the end to identify the polarization branch parameters. Due to the random point selection, the parameters of each sub-spectral line are not unique, which reduces the credibility of the subsequent polarization equivalent circuit parameter identification results. Third, the frequency domain dielectric spectrum decomposition method mainly performs a first differentiation on the frequency domain dielectric spectrum. The amplitude of its sub-spectral lines is small, and the peak half-maximum full width area is long, so that some sub-spectral lines with relatively close peak points will affect each other, causing the individual peak points of the first differential spectrum line of the frequency domain dielectric spectrum to be offset or not obvious, which has a certain impact on the subsequent use of peak point coordinates to identify the accuracy of polarization equivalent circuit parameters.

[0004] In view of this, this application is filed. Summary of the Invention

[0005] The present invention provides a method and device for identifying parameters of polarization equivalent circuit of oil-paper insulated equipment, which can at least partially improve the above-mentioned problem.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment, comprising:

[0008] The extended Debye equivalent circuit model is used to characterize the insulation system of the oil-paper insulation equipment to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit;

[0009] Obtaining a measured real part spectrum line of complex capacitance, and performing geometric capacitance elimination processing on the measured real part spectrum line of complex capacitance to obtain a polarized real part spectrum line of complex capacitance;

[0010] Differentiating the real part of the polarized complex capacitance of the polarized equivalent circuit to obtain a first differential spectrum of the real part of the polarized complex capacitance, a second differential spectrum of the real part of the polarized complex capacitance, and a second differential molecular spectrum function of the real part of the polarized complex capacitance, and converting the horizontal coordinates of the second differential spectrum of the real part of the polarized complex capacitance;

[0011] Combined with the coordinates of the peak points of each sub-spectral line in the actual coordinate axis, the real part of the secondary micro-molecular spectrum function of the polarization complex capacitance is analyzed and processed to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches;

[0012] The peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance are selected and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches for identification processing to generate parameter identification results, wherein the identification processing is to select the first peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

[0013] The present invention also provides a device for identifying parameters of polarization equivalent circuit of oil-paper insulated equipment, comprising:

[0014] An equivalent circuit unit is used to characterize the insulation system of the oil-paper insulation equipment using an extended Debye equivalent circuit model to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit;

[0015] a polarization complex capacitance real part spectrum line generating unit, configured to obtain a measured complex capacitance real part spectrum line, and perform geometric capacitance elimination processing on the measured complex capacitance real part spectrum line to obtain a polarization complex capacitance real part spectrum line;

[0016] a differential unit for performing differential processing on the real part of the polarization complex capacitance of the polarization equivalent circuit to obtain a first differential spectrum line of the real part of the polarization complex capacitance, a second differential spectrum line of the real part of the polarization complex capacitance, and a second differential molecular spectrum line function of the real part of the polarization complex capacitance, and performing conversion processing on the horizontal coordinates of the second differential spectrum line of the real part of the polarization complex capacitance;

[0017] An analysis unit is used to analyze and process the real part of the polarization complex capacitance secondary micro-molecular spectrum line function by combining the coordinates of the peak points of each sub-spectral line in the actual coordinate axis to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches;

[0018] An identification result generating unit is used to select the peak point coordinates of the real part quadratic differential spectrum of the polarization complex capacitance and perform identification processing in combination with the polarization capacitance, time constant and polarization resistance of the different polarization branches to generate parameter identification results, wherein the identification processing is to select the first peak point coordinates of the real part quadratic differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

[0019] In summary, the polarization equivalent circuit parameter identification method for oil-paper insulated equipment has the following advantages compared with the existing technology:

[0020] 1. The frequency-domain dielectric spectrum second-differentiation decomposition method is used to identify the polarization equivalent circuit parameters by constructing the second-differentiation spectrum of the real part of the polarization complex capacitance. The sub-spectral line has a large amplitude and a short peak full-width at half maximum. The latter sub-spectral line has little effect on the peak point of the previous sub-spectral line, making the peak points of the second-differentiation spectrum of the real part of the polarization complex capacitance clear, eliminating the difficulty in accurately determining the peak point location and extracting the peak point coordinates, effectively improving the accuracy of parameter identification;

[0021] 2. The coordinates of each peak point of the constructed polarization complex capacitance real part quadratic differential spectrum are unique and unaffected by adjacent sub-spectral lines. The polarization equivalent circuit parameters are identified by unique and accurate peak point coordinates, rather than randomly selecting two points at the end of the sub-spectral line, which can effectively ensure the uniqueness and accuracy of the parameter identification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a flow chart of a method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment provided by the first embodiment of the present invention;

[0023] Figure 2is a circuit diagram based on the Debye extended model equivalent circuit provided by the first embodiment of the present invention;

[0024] Figure 3 This is a comparison diagram of two sub-spectral lines provided by the first embodiment of the present invention;

[0025] Figure 4 is the first sub-spectral line diagram provided by the first embodiment of the present invention;

[0026] Figure 5 is the second sub-spectral line diagram provided by the first embodiment of the present invention;

[0027] Figure 6 is the third sub-spectral line diagram provided by the first embodiment of the present invention;

[0028] Figure 7 is the fourth sub-spectral line diagram provided by the first embodiment of the present invention;

[0029] Figure 8 is the fifth sub-spectral line diagram provided by the first embodiment of the present invention;

[0030] Figure 9 is the sixth sub-spectral line diagram provided by the first embodiment of the present invention;

[0031] Figure 10 This is a graph showing the results of the second differential spectrum analysis of the real part of the polarized complex capacitance provided by the first embodiment of the present invention;

[0032] Figure 11 This is a comparison diagram of two differential spectral lines provided by the first embodiment of the present invention;

[0033] Figure 12 This is a comparison diagram between the actual value of the real part spectrum line of the complex capacitance and the decomposition spectrum value provided by the first embodiment of the present invention;

[0034] Figure 13 This is a module schematic diagram of a device for determining the number of polarization branches in an extended Debye equivalent circuit of oil-paper insulated equipment provided by a second embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] refer to Figure 1 As shown, the first embodiment of the present invention discloses a method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment. The method can be executed by an oil-paper insulated equipment polarization equivalent circuit parameter identification device (hereinafter referred to as the identification device), and in particular, by one or more processors within the identification device to implement the following method:

[0037] S101, characterizing the insulation system of the oil-paper insulation equipment using an extended Debye equivalent circuit model to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit;

[0038] S102, obtaining a measured real part spectrum line of complex capacitance, and performing geometric capacitance elimination processing on the measured real part spectrum line of complex capacitance to obtain a polarized real part spectrum line of complex capacitance;

[0039] Specifically, step S102 includes: the equivalent admittance based on the Debye extended model equivalent circuit is:

[0040]

[0041] in, is the equivalent admittance between the ports of the equivalent circuit, is the imaginary part sign, To test the angular frequency, is the complex capacitance, is the insulation resistance, is the geometric capacitance at power frequency, is the number of polarization branches in the polarization equivalent circuit, For the The polarization resistance of each polarization branch, For the The polarization capacitance of each polarization branch;

[0042] The equivalent circuit based on the Debye extended model after equivalent admittance is transformed to obtain the complex capacitance , the formula is:

[0043]

[0044] Get the complex capacitance The real and imaginary parts of are given by:

[0045]

[0046]

[0047] in, is the time constant;

[0048] According to the above formula, the real part of the polarization complex capacitance of the polarization equivalent circuit is obtained , the formula is:

[0049]

[0050] Among them, the real part of the polarization complex capacitance of the polarization equivalent circuit is It is composed of the superposition of multiple sub-spectral lines with different relaxation time constants.

[0051] In this embodiment, the extended Debye equivalent circuit structure of the oil-paper insulation equipment insulation system is as follows: Figure 2 As shown, it is mainly composed of a geometric equivalent circuit (including insulation resistance R g , geometric capacitance C g ) and a polarization equivalent circuit (containing N RC series branches). Figure 2 It can be obtained that the equivalent admittance of the extended Debye equivalent circuit is:

[0052] (1)

[0053] Formula (1) can be transformed to obtain the complex capacitance for

[0054] (2)

[0055] From formula (2), the real part of the complex capacitance can be obtained as

[0056] (3)

[0057] deduct , obtain the real part of the polarization complex capacitance:

[0058] (4)

[0059] S103, performing differentiation processing on the real part of the polarization complex capacitance of the polarization equivalent circuit to obtain a first differential spectrum line of the real part of the polarization complex capacitance, a second differential spectrum line of the real part of the polarization complex capacitance, and a second differential molecular spectrum line function of the real part of the polarization complex capacitance, and performing conversion processing on the horizontal coordinates of the second differential spectrum line of the real part of the polarization complex capacitance;

[0060] Specifically, step S103 includes: the real part of the polarization complex capacitance of the polarization equivalent circuit Perform differential processing, let ,right Differentiate and get the first differential spectrum of the real part of the polarized complex capacitance , the formula is:

[0061]

[0062] in, is the horizontal axis variable exponential function of change;

[0063] First differential spectrum of the real part of polarized complex capacitance Multiply both ends of the formula by , and then differentiate to obtain the polarization complex capacitance real part second differential spectrum line and polarization complex capacitance real part secondary micromolecular spectral line function , the formula is:

[0064]

[0065]

[0066] in, is the horizontal axis variable;

[0067] The horizontal axis Convert to , so that the real part of the polarization complex capacitance second differential spectrum line The peak point is clearer.

[0068] In this embodiment, the real part of the polarized complex capacitance is differentiated, and ,right Differentiate and get the first differential spectrum of the real part of the polarized complex capacitance :

[0069] (5)

[0070] Multiply both ends of equation (5) by , and then differentiate to obtain the polarization complex capacitance real part second differential spectrum line :

[0071] (6)

[0072] (7)

[0073] in is the quadratic micro-molecular spectral line function of the real part of the polarized complex capacitance (hereinafter referred to as the sub-spectral line function, and the corresponding curve is called the sub-spectral line).

[0074] In order to study the characteristics of sub-spectral line functions, two sub-spectral line functions with a time constant difference of 6 times are taken for comparative analysis. , , the two sub-spectral lines are as follows Figure 3 shown.

[0075] By the sub-spectral line function characteristics and Figure 3 The comparison results show that the polarization complex capacitance real part second differential spectrum line Features include:

[0076] Feature 1: Each sub-spectral line has a unique peak point , and gradually decays to 0 on both sides of the peak, and the sub-spectral lines The smaller it is, the overall shift is to the right;

[0077] Characteristic 2: It is composed of N sub-spectral lines with different time constants. The number of spectral line peaks is the number of polarization branches in the extended Debye equivalent model.

[0078] Feature 3: The previous sub-spectral line has a greater impact on the next sub-spectral line, but the next sub-spectral line has little impact on the peak point of the previous sub-spectral line;

[0079] Feature 4: By performing spectrum analysis from the first peak point in sequence, the conditions of each sub-spectral line can be obtained.

[0080] S104, analyzing and processing the real part of the polarization complex capacitance secondary micro-molecular spectrum function based on the coordinates of the peak points of each sub-spectral line in the actual coordinate axis to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches;

[0081] Specifically, step S104 includes: polarization complex capacitance real part secondary micro-molecule spectrum function After analysis, the coordinates of the peak point are obtained as , combined with the peak point coordinates of each sub-spectral line in the actual coordinate axis , the polarization capacitance, time constant and polarization resistance of different polarization branches are obtained by solving the formula: .

[0082] In this embodiment, by From the analysis, we can see that the coordinates of its peak point are , combined with the peak point coordinates of each sub-spectral line in the actual coordinate axis , the polarization capacitance, time constant and polarization resistance of different polarization branches can be solved, that is:

[0083] (8)

[0084] S105, select the peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and perform identification processing in combination with the polarization capacitance, time constant and polarization resistance of the different polarization branches to generate a parameter identification result, wherein the identification processing is to select the first peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve and obtain the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

[0085] Specifically, step S105 includes: selecting the real part of the polarized complex capacitance second differential spectrum line The coordinates of the first peak point , and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches, the first sub-spectral line is obtained and the corresponding polarization capacitance of polarization branch 1 , time constant and polarization resistance ;

[0086] Subtract the first subline from the current differential line Get the remaining spectrum , from the remaining spectral lines Select the coordinates of the first peak point , and the second sub-spectral line is solved by combining the polarization capacitance, time constant and polarization resistance of the different polarization branches and the corresponding polarization capacitance of polarization branch 2 , time constant and polarization resistance ;

[0087] Subtract the second sub-spectral line from the current differential spectral line Get the remaining spectrum , repeat the above steps until the last peak point is calculated , complete the decomposition of all sub-spectral lines and the identification of polarization branch parameters, and generate parameter identification results.

[0088] In this embodiment, the real part of the polarized complex capacitance second differential spectrum line is selected. Coordinates of the first peak point , and combined with formula (8) to solve the first sub-spectral line and the corresponding polarization capacitance of polarization branch 1 , time constant and polarization resistance Subtract the first sub-spectral line from the current differential spectral line Get the remaining spectrum ; Then from the remaining spectral lines Select the coordinates of the first peak point , and combined with formula (8) to solve the second sub-spectral line and the corresponding polarization capacitance of polarization branch 2 , time constant and polarization resistance Subtract the second sub-spectral line from the current differential spectral line Get the remaining spectrum , repeat step S105, and so on until the last peak point , complete the decomposition of all sub-spectral lines and the identification of polarization branch parameters.

[0089] Specifically, in this embodiment, in order to further demonstrate the advantages of the polarization equivalent circuit parameter identification method of the oil-paper insulation equipment, the following experimental verification is carried out: the extended Debye equivalent circuit parameters of a 220kV oil-immersed transformer T1 are shown in Table 1. The polarization complex capacitance real part of the transformer T1 is subjected to differential spectrum decomposition and equivalent circuit parameter identification using the method proposed in this patent. The spectrum decomposition process is as follows: Figures 4 to 9 The final spectrum decomposition result is shown as Figure 10 The transformer parameters are shown in Table 1:

[0090] Table 1 Transformer T1 extended Debye equivalent circuit parameters

[0091]

[0092] Depend on Figure 10 It can be clearly determined that the real part of the second differential spectrum of the polarization complex capacitance has 6 peak points. It can be judged that the transformer equivalent circuit contains 6 polarization branches, which is consistent with the actual equivalent circuit situation. It verifies the reliability of the method proposed in this paper for determining the number of polarization branches in the equivalent circuit of oil-paper insulated equipment. Figures 4 to 9 The coordinates of the peak points of each sub-spectral line are shown in Table 2, and the parameters of each polarization branch obtained by combining equation (8) are shown in Table 3.

[0093] Table 2 Coordinates of each peak point

[0094]

[0095] Table 3 Polarization branch parameter identification results

[0096]

[0097] As shown in Table 3, the maximum relative error between the extended Debye polarization branch parameter values ​​obtained by the second differential decomposition method of the real part of the polarization complex capacitance and the measured values ​​does not exceed 2%. Figure 11 is the agreement between the real part second differential spectrum of the polarized complex capacitance obtained based on the sub-spectral line solution and its original spectrum line, Figure 12 The real part spectrum of the complex capacitance obtained based on the sub-spectral line is consistent with its original spectrum. Figure 11 、 Figure 12 The consistent results further verify the accuracy of using the peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance to identify the parameters of the extended Debye polarization equivalent circuit.

[0098] In summary, the polarization equivalent circuit parameter identification method for oil-paper insulated equipment has the following advantages compared with the existing technology:

[0099] 1. The frequency-domain dielectric spectrum second-differentiation decomposition method is used to identify the polarization equivalent circuit parameters by constructing the second-differentiation spectrum of the real part of the polarization complex capacitance. The sub-spectral line has a large amplitude and a short peak full-width at half maximum. The latter sub-spectral line has little effect on the peak point of the previous sub-spectral line, making the peak points of the second-differentiation spectrum of the real part of the polarization complex capacitance clear, eliminating the difficulty in accurately determining the peak point location and extracting the peak point coordinates, effectively improving the accuracy of parameter identification;

[0100] 2. The coordinates of each peak point of the constructed polarization complex capacitance real part quadratic differential spectrum are unique and unaffected by adjacent sub-spectral lines. The polarization equivalent circuit parameters are identified by unique and accurate peak point coordinates, rather than randomly selecting two points at the end of the sub-spectral line, which can effectively ensure the uniqueness and accuracy of the parameter identification results.

[0101] See also Figure 13 The second embodiment of the present invention further provides a device for identifying polarization equivalent circuit parameters of oil-paper insulated equipment, which includes:

[0102] An equivalent circuit unit 201 is used to characterize the insulation system of the oil-paper insulation equipment using an extended Debye equivalent circuit model to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit;

[0103] The polarization complex capacitance real part spectrum line generating unit 202 is used to obtain the measured complex capacitance real part spectrum line and remove the geometric capacitance from the measured complex capacitance real part spectrum line to obtain the polarization complex capacitance real part spectrum line;

[0104] a differential unit 203 configured to perform differential processing on the real part of the polarization complex capacitance of the polarization equivalent circuit to obtain a first differential spectrum line of the real part of the polarization complex capacitance, a second differential spectrum line of the real part of the polarization complex capacitance, and a second differential molecular spectrum line function of the real part of the polarization complex capacitance, and to convert the horizontal coordinates of the second differential spectrum line of the real part of the polarization complex capacitance;

[0105] An analysis unit 204 is configured to analyze and process the real part of the polarization complex capacitance secondary micro-molecular spectral line function by combining the coordinates of the peak points of each sub-spectral line in the actual coordinate axis to obtain the polarization capacitance, time constant, and polarization resistance of different polarization branches;

[0106] The identification result generation unit 205 is used to select the peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and perform identification processing in combination with the polarization capacitance, time constant and polarization resistance of the different polarization branches to generate a parameter identification result, wherein the identification processing is to select the first peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of the polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

[0107] Preferably, the measured real part spectrum line of the complex capacitance is obtained, and the measured real part spectrum line of the complex capacitance is subjected to geometric capacitance elimination processing to obtain the polarized real part spectrum line of the complex capacitance, specifically:

[0108] The equivalent admittance based on the Debye extended model equivalent circuit is:

[0109]

[0110] in, is the equivalent admittance between the ports of the equivalent circuit, is the imaginary part sign, To test the angular frequency, is the complex capacitance, is the insulation resistance, is the geometric capacitance at power frequency, is the number of polarization branches in the polarization equivalent circuit, For the The polarization resistance of each polarization branch, For the The polarization capacitance of each polarization branch;

[0111] The equivalent circuit based on the Debye extended model after equivalent admittance is transformed to obtain the complex capacitance , the formula is:

[0112]

[0113] Get the complex capacitance The real and imaginary parts of are given by:

[0114]

[0115]

[0116] in, is the time constant;

[0117] According to the above formula, the real part of the polarization complex capacitance of the polarization equivalent circuit is obtained , the formula is:

[0118]

[0119] Among them, the real part of the polarization complex capacitance of the polarization equivalent circuit is It is composed of the superposition of multiple sub-spectral lines with different relaxation time constants.

[0120] Preferably, the real part of the polarized complex capacitance of the polarization equivalent circuit is differentiated to obtain a first differential spectrum of the real part of the polarized complex capacitance, a second differential spectrum of the real part of the polarized complex capacitance, and a second differential molecular spectrum function of the real part of the polarized complex capacitance, and the abscissa of the second differential spectrum of the real part of the polarized complex capacitance is converted, specifically as follows:

[0121] Real part of polarization complex capacitance of polarization equivalent circuit Perform differential processing, let ,right Differentiate and get the first differential spectrum of the real part of the polarized complex capacitance , the formula is:

[0122]

[0123] in, is the horizontal axis variable exponential function of change;

[0124] First differential spectrum of the real part of polarized complex capacitance Multiply both ends of the formula by , and then differentiate to obtain the polarization complex capacitance real part second differential spectrum line and polarization complex capacitance real part secondary micromolecular spectral line function , the formula is:

[0125]

[0126]

[0127] in, is the horizontal axis variable;

[0128] The horizontal axis Convert to , so that the real part of the polarization complex capacitance second differential spectrum line The peak point is clearer.

[0129] Preferably, the polarization capacitance, time constant and polarization resistance of different polarization branches are obtained by analyzing and processing the real part of the secondary micro-molecular spectrum function of the polarization complex capacitance in combination with the coordinates of the peak points of each sub-spectral line in the actual coordinate axis, specifically:

[0130] Secondary micromolecular spectral line function of the real part of polarization complex capacitance After analysis, the coordinates of the peak point are obtained as , combined with the peak point coordinates of each sub-spectral line in the actual coordinate axis , the polarization capacitance, time constant and polarization resistance of different polarization branches are obtained by solving the formula: .

[0131] Preferably, the peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance are selected and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches to perform identification processing to generate parameter identification results, specifically:

[0132] Select the real part of the polarized complex capacitance second differential spectrum line The coordinates of the first peak point , and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches, the first sub-spectral line is obtained and the corresponding polarization capacitance of polarization branch 1 , time constant and polarization resistance ;

[0133] Subtract the first subline from the current differential line Get the remaining spectrum , from the remaining spectral lines Select the coordinates of the first peak point , and the second sub-spectral line is solved by combining the polarization capacitance, time constant and polarization resistance of the different polarization branches and the corresponding polarization capacitance of polarization branch 2 , time constant and polarization resistance ;

[0134] Subtract the second sub-spectral line from the current differential spectral line Get the remaining spectrum , repeat the above steps until the last peak point is calculated , complete the decomposition of all sub-spectral lines and the identification of polarization branch parameters, and generate parameter identification results.

[0135] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment, characterized in that: include: The extended Debye equivalent circuit model is used to characterize the insulation system of the oil-paper insulation equipment to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit; Obtaining a measured real part spectrum line of complex capacitance, and performing geometric capacitance elimination processing on the measured real part spectrum line of complex capacitance to obtain a polarized real part spectrum line of complex capacitance; Differentiating the real part of the polarized complex capacitance of the polarized equivalent circuit to obtain a first differential spectrum of the real part of the polarized complex capacitance, a second differential spectrum of the real part of the polarized complex capacitance, and a second differential molecular spectrum function of the real part of the polarized complex capacitance, and converting the horizontal coordinates of the second differential spectrum of the real part of the polarized complex capacitance; Combined with the coordinates of the peak points of each sub-spectral line in the actual coordinate axis, the real part of the secondary micro-molecular spectrum function of the polarization complex capacitance is analyzed and processed to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches; The peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance are selected and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches for identification processing to generate parameter identification results, wherein the identification processing is to select the first peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

2. The method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment according to claim 1, characterized in that: Obtain the measured complex capacitance real part spectrum line, and remove the geometric capacitance from the measured complex capacitance real part spectrum line to obtain the polarized complex capacitance real part spectrum line, specifically: The equivalent admittance based on the Debye extended model equivalent circuit is: in, is the equivalent admittance between the ports of the equivalent circuit, is the imaginary part sign, To test the angular frequency, is the complex capacitance, is the insulation resistance, is the geometric capacitance at power frequency, is the number of polarization branches in the polarization equivalent circuit, For the The polarization resistance of each polarization branch, For the The polarization capacitance of each polarization branch; The equivalent circuit based on the Debye extended model after equivalent admittance is transformed to obtain the complex capacitance , the formula is: Get the complex capacitance The real and imaginary parts of are given by: in, is the time constant; According to the above formula, the real part of the polarization complex capacitance of the polarization equivalent circuit is obtained , the formula is: Among them, the real part of the polarization complex capacitance of the polarization equivalent circuit is It is composed of the superposition of multiple sub-spectral lines with different relaxation time constants.

3. The method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment according to claim 2, characterized in that: The polarization complex capacitance real part of the polarization equivalent circuit is differentiated to obtain the polarization complex capacitance real part first differential spectrum line, the polarization complex capacitance real part second differential spectrum line and the polarization complex capacitance real part second differential molecular spectrum line function, and the abscissa of the polarization complex capacitance real part second differential spectrum line is converted, specifically: Real part of polarization complex capacitance of polarization equivalent circuit Perform differential processing, let ,right Differentiate and get the first differential spectrum of the real part of the polarized complex capacitance , the formula is: in, is the horizontal axis variable exponential function of change; First differential spectrum of the real part of polarized complex capacitance Multiply both ends of the formula by , and then differentiate to obtain the polarization complex capacitance real part second differential spectrum line and polarization complex capacitance real part secondary micromolecular spectral line function , the formula is: in, is the horizontal axis variable; The horizontal axis Convert to , so that the real part of the polarization complex capacitance second differential spectrum line The peak point is clearer.

4. The method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment according to claim 3, characterized in that: Combined with the coordinates of the peak points of each sub-spectral line in the actual coordinate axis, the real part of the secondary micro-molecular spectrum function of the polarization complex capacitance is analyzed and processed to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches, specifically: Secondary micromolecular spectral line function of the real part of polarization complex capacitance After analysis, the coordinates of the peak point are obtained as , combined with the peak point coordinates of each sub-spectral line in the actual coordinate axis , the polarization capacitance, time constant and polarization resistance of different polarization branches are obtained by solving the formula: .

5. The method for identifying polarization equivalent circuit parameters of oil-paper insulated equipment according to claim 4, characterized in that: The peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance are selected and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches to perform identification processing to generate parameter identification results, specifically: Select the real part of the polarized complex capacitance second differential spectrum line The coordinates of the first peak point , and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches, the first sub-spectral line is obtained and the corresponding polarization capacitance of polarization branch 1 , time constant and polarization resistance ; Subtract the first subline from the current differential line Get the remaining spectrum , from the remaining spectral lines Select the coordinates of the first peak point , and the second sub-spectral line is solved by combining the polarization capacitance, time constant and polarization resistance of the different polarization branches and the corresponding polarization capacitance of polarization branch 2 , time constant and polarization resistance ; Subtract the second sub-spectral line from the current differential spectral line Get the remaining spectrum , repeat the above steps until the last peak point is calculated , complete the decomposition of all sub-spectral lines and the identification of polarization branch parameters, and generate parameter identification results.

6. A polarization equivalent circuit parameter identification device for oil-paper insulation equipment, characterized in that: include: An equivalent circuit unit is used to characterize the insulation system of the oil-paper insulation equipment using an extended Debye equivalent circuit model to obtain an equivalent circuit based on the extended Debye model, wherein the equivalent circuit based on the extended Debye model includes a geometric equivalent circuit and a polarization equivalent circuit; a polarization complex capacitance real part spectrum line generating unit, configured to obtain a measured complex capacitance real part spectrum line, and perform geometric capacitance elimination processing on the measured complex capacitance real part spectrum line to obtain a polarization complex capacitance real part spectrum line; a differential unit for performing differential processing on the real part of the polarization complex capacitance of the polarization equivalent circuit to obtain a first differential spectrum line of the real part of the polarization complex capacitance, a second differential spectrum line of the real part of the polarization complex capacitance, and a second differential molecular spectrum line function of the real part of the polarization complex capacitance, and performing conversion processing on the horizontal coordinates of the second differential spectrum line of the real part of the polarization complex capacitance; An analysis unit is used to analyze and process the real part of the polarization complex capacitance secondary micro-molecular spectrum line function by combining the coordinates of the peak points of each sub-spectral line in the actual coordinate axis to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches; An identification result generating unit is used to select the peak point coordinates of the real part quadratic differential spectrum of the polarization complex capacitance and perform identification processing in combination with the polarization capacitance, time constant and polarization resistance of the different polarization branches to generate parameter identification results, wherein the identification processing is to select the first peak point coordinates of the real part quadratic differential spectrum of the polarization complex capacitance and combine the polarization capacitance, time constant and polarization resistance of the different polarization branches to solve the first sub-spectrum line and the corresponding polarization capacitance, time constant and polarization resistance of polarization branch 1, and subtract the first sub-spectrum line from the current differential spectrum line to obtain the remaining spectrum line, and continue to select the first peak point coordinates from the remaining spectrum lines for solution until the last peak point is calculated.

7. The polarization equivalent circuit parameter identification device for oil-paper insulated equipment according to claim 6, characterized in that: Obtain the measured complex capacitance real part spectrum line, and remove the geometric capacitance from the measured complex capacitance real part spectrum line to obtain the polarized complex capacitance real part spectrum line, specifically: The equivalent admittance based on the Debye extended model equivalent circuit is: in, is the equivalent admittance between the ports of the equivalent circuit, is the imaginary part sign, To test the angular frequency, is the complex capacitance, is the insulation resistance, is the geometric capacitance at power frequency, is the number of polarization branches in the polarization equivalent circuit, For the The polarization resistance of each polarization branch, For the The polarization capacitance of each polarization branch; The equivalent circuit based on the Debye extended model after equivalent admittance is transformed to obtain the complex capacitance , the formula is: Get the complex capacitance The real and imaginary parts of are given by: in, is the time constant; According to the above formula, the real part of the polarization complex capacitance of the polarization equivalent circuit is obtained , the formula is: Among them, the real part of the polarization complex capacitance of the polarization equivalent circuit is It is composed of the superposition of multiple sub-spectral lines with different relaxation time constants.

8. The polarization equivalent circuit parameter identification device for oil-paper insulated equipment according to claim 7, characterized in that: The polarization complex capacitance real part of the polarization equivalent circuit is differentiated to obtain the polarization complex capacitance real part first differential spectrum line, the polarization complex capacitance real part second differential spectrum line and the polarization complex capacitance real part second differential molecular spectrum line function, and the abscissa of the polarization complex capacitance real part second differential spectrum line is converted, specifically: Real part of polarization complex capacitance of polarization equivalent circuit Perform differential processing, let ,right Differentiate and get the first differential spectrum of the real part of the polarized complex capacitance , the formula is: in, is the horizontal axis variable exponential function of change; First differential spectrum of the real part of polarized complex capacitance Multiply both ends of the formula by , and then differentiate to obtain the polarization complex capacitance real part second differential spectrum line and polarization complex capacitance real part secondary micromolecular spectral line function , the formula is: in, is the horizontal axis variable; The horizontal axis Convert to , so that the real part of the polarization complex capacitance second differential spectrum line The peak point is clearer.

9. The polarization equivalent circuit parameter identification device for oil-paper insulated equipment according to claim 8, characterized in that: Combined with the coordinates of the peak points of each sub-spectral line in the actual coordinate axis, the real part of the secondary micro-molecular spectrum function of the polarization complex capacitance is analyzed and processed to obtain the polarization capacitance, time constant and polarization resistance of different polarization branches, specifically: Secondary micromolecular spectral line function of the real part of polarization complex capacitance After analysis, the coordinates of the peak point are obtained as , combined with the peak point coordinates of each sub-spectral line in the actual coordinate axis , the polarization capacitance, time constant and polarization resistance of different polarization branches are obtained by solving the formula: .

10. The polarization equivalent circuit parameter identification device for oil-paper insulated equipment according to claim 9, characterized in that: The peak point coordinates of the real part of the second differential spectrum of the polarization complex capacitance are selected and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches to perform identification processing to generate parameter identification results, specifically: Select the real part of the polarized complex capacitance second differential spectrum line The coordinates of the first peak point , and combined with the polarization capacitance, time constant and polarization resistance of the different polarization branches, the first sub-spectral line is obtained and the corresponding polarization capacitance of polarization branch 1 , time constant and polarization resistance ; Subtract the first subline from the current differential line Get the remaining spectrum , from the remaining spectral lines Select the coordinates of the first peak point , and the second sub-spectral line is solved by combining the polarization capacitance, time constant and polarization resistance of the different polarization branches and the corresponding polarization capacitance of polarization branch 2 , time constant and polarization resistance ; Subtract the second sub-spectral line from the current differential spectral line Get the remaining spectrum , repeat the above steps until the last peak point is calculated , complete the decomposition of all sub-spectral lines and the identification of polarization branch parameters, and generate parameter identification results.

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