Calculation method, system and device for insulating-medium loss, and medium

Abstract

A calculation method, system and device for an insulating-medium loss, and a medium. The method comprises: first, by means of a step-response function, representing a high-frequency square-wave voltage applied to an epoxy resin to be subjected to calculation, and in combination with the Fourier series, constructing an expression of an insulating-medium loss under the excitation of the high-frequency square-wave voltage (step 101); next, by means of a narrow step function, representing a spike voltage applied to said epoxy resin, and in combination with the Fourier series, constructing an expression of an insulating-medium loss under the excitation of the spike voltage (step 102); then, by means of a finite summation method, calculating an additional medium loss of when a spectral overlap between the high-frequency square-wave voltage and the spike voltage occurs (step 103); and finally, superposing the additional medium loss, the insulating-medium loss under the high-frequency square-wave voltage and the insulating-medium loss under the spike voltage, so as to obtain an expression of the total insulating-medium loss (step 104). Thus, an accurate calculation method for an insulating-medium loss of an epoxy resin under a non-sinusoidal voltage is provided.

Description

A method, system, equipment, and medium for calculating the loss of an insulating dielectric.

[0001] This application claims priority to Chinese Patent Application No. 202411031205.6, filed on July 30, 2024, entitled "A method, system, device and medium for calculating insulation dielectric loss", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of insulation loss calculation technology, and in particular to a method, system, device and medium for calculating insulation dielectric loss. Background Technology

[0003] As the voltage levels and power of power electronic equipment continue to increase, high-frequency power electronic devices need to withstand transient bipolar square waves from both the front and rear stages of DC-DC converters. The rapid turn-on and turn-off of power semiconductor devices cause rapid voltage or current rise times (high dv / dt and di / dt). Combined with stray parameters such as leakage inductance and distributed capacitance in high-frequency transformers, peak voltages and transient overvoltage oscillations appear on the rising edges of the square waves during high-frequency operation. Under this complex non-sinusoidal electro-thermal stress, the insulation system of high-frequency power electronic devices is prone to partial discharge, aging, deterioration, and even breakdown. Taking epoxy resin as an example, the breakdown field strength at high frequencies (8kHz) is reduced by 17% compared to low frequencies (500Hz), severely impacting the reliable operation of high-frequency power electronic devices.

[0004] Insulating dielectric losses are mainly divided into conductivity losses and polarization losses. When an external voltage is applied across the ends of an insulating dielectric, current flows through the dielectric, and the loss generated in the dielectric at this time is called conductivity loss. Electron displacement polarization and ion displacement polarization of a dielectric are completed instantaneously; these two polarization methods are called instantaneous polarization, and the resulting losses can be ignored under certain conditions. Dipole polarization and interface polarization require a longer time and are also called relaxation polarization, both of which consume energy.

[0005] Currently, calculations of dielectric loss mainly focus on the loss angle δ and the loss factor tanδ. Calculations for dielectric loss under high-frequency non-sinusoidal voltages and peak voltages are rare. However, due to the strong frequency dependence of dielectric loss, higher harmonic components cannot be ignored. Furthermore, the loss of epoxy resin, a commonly used solid insulating material in high-frequency transformers, increases rapidly above its glass transition temperature, further increasing the probability of failure. Therefore, accurate calculation of dielectric loss of insulating materials under high-frequency square waves and peak voltages is crucial for accurately calculating the temperature field of high-frequency transformers and determining their safe and stable operation. Summary of the Invention

[0006] This application provides a method, system, device, and medium for calculating the dielectric loss of epoxy resin insulation under non-sinusoidal voltage.

[0007] In view of the above, the first aspect of this application provides a method for calculating the dielectric loss of an insulating medium, the method comprising:

[0008] The high-frequency square wave voltage of the epoxy resin under calculation is represented by the step response function, and the expression for the insulation dielectric loss under the high-frequency square wave voltage excitation is constructed by combining the Fourier series.

[0009] The peak voltage of the epoxy resin under calculation is represented by a narrow step function, and an expression for the dielectric loss of the insulating medium under the peak voltage excitation is constructed by combining Fourier series.

[0010] The additional dielectric loss when the spectrum of the high-frequency square wave voltage overlaps with that of the peak voltage is calculated using a finite summation method.

[0011] The additional dielectric loss, the high-frequency square wave voltage, and the peak voltage insulation dielectric loss are superimposed to obtain the expression for the total insulation dielectric loss, which is used to calculate the epoxy resin insulation dielectric loss under non-sinusoidal conditions.

[0012] Optionally, the step response function is used to represent the high-frequency square wave voltage of the epoxy resin to be calculated, and combined with Fourier series, an expression for the dielectric loss under the high-frequency square wave voltage excitation is constructed, specifically including:

[0013] The high-frequency square wave voltage of the epoxy resin under calculation is represented by the step response function of the low-pass filter, and the effective value of the harmonic components of the high-frequency square wave voltage is obtained by combining the step response function with the Fourier series.

[0014] Substituting the effective value of the harmonic components of the high-frequency square wave voltage into the superposition expression of dielectric loss under different harmonic voltages, we obtain the expression for the dielectric loss under the high-frequency square wave voltage excitation. By introducing a correction coefficient, we correct the expression for the dielectric loss to obtain the final expression for the dielectric loss.

[0015] Optionally, the step of representing the peak voltage of the epoxy resin under calculation using a narrow step function and constructing an expression for the dielectric loss of the insulation under the peak voltage excitation by combining Fourier series specifically includes:

[0016] The peak voltage of the epoxy resin to be calculated is regarded as a narrow square waveform and represented by a narrow step function. The effective value of the harmonic components of the peak voltage is calculated by combining the narrow step function with the Fourier series.

[0017] Substituting the effective value of the harmonic components of the peak voltage into the superposition expression of dielectric loss under different harmonic voltages, we obtain the expression for the dielectric loss under the peak voltage excitation. Then, we divide the expression for the dielectric loss under the peak voltage excitation into two parts and calculate the difference between them to obtain the final expression for the dielectric loss.

[0018] Optionally, the expression for the total loss of the insulating medium is:

[0019] In the formula, P total P is the total dielectric loss, where P is the dielectric loss under the high-frequency square wave voltage excitation. a P represents the dielectric loss under the peak voltage excitation. ST The additional dielectric loss is given by r, the correction coefficient is given by m, the ratio of the peak voltage amplitude to the high-frequency square wave amplitude is given by d(k), the coefficient depends on k is given by q(k), and k is a positive integer. c f is the cutoff frequency. s The frequency of the high-frequency square wave is given by C0, where C0 is the vacuum capacitor and V is the voltage. sq ε″ represents the amplitude of the high-frequency square wave, and ε″ represents the imaginary part of the complex permittivity.

[0020] A second aspect of this application provides a system for calculating the loss of insulating dielectric, the system comprising:

[0021] The first building unit is used to represent the high-frequency square wave voltage of the epoxy resin to be calculated through the step response function, and to construct the expression of the insulation dielectric loss under the high-frequency square wave voltage excitation by combining the Fourier series.

[0022] The second building unit is used to represent the peak voltage of the epoxy resin to be calculated using a narrow step function, and to construct an expression for the insulation dielectric loss under the peak voltage excitation by combining Fourier series.

[0023] The first calculation unit is used to calculate the additional dielectric loss when the spectrum of the high-frequency square wave voltage overlaps with that of the peak voltage by a finite summation method.

[0024] The second calculation unit is used to superimpose the additional dielectric loss, the high-frequency square wave voltage, and the peak voltage insulation dielectric loss to obtain the total insulation dielectric loss expression, which is used to calculate the epoxy resin insulation dielectric loss under non-sinusoidal conditions.

[0025] Optionally, the first building unit is specifically used for:

[0026] The high-frequency square wave voltage of the epoxy resin under calculation is represented by the step response function of the low-pass filter, and the effective value of the harmonic components of the high-frequency square wave voltage is obtained by combining the step response function with the Fourier series.

[0027] Substituting the effective value of the harmonic components of the high-frequency square wave voltage into the superposition expression of dielectric loss under different harmonic voltages, we obtain the expression for the dielectric loss under the high-frequency square wave voltage excitation. By introducing a correction coefficient, we correct the expression for the dielectric loss to obtain the final expression for the dielectric loss.

[0028] Optionally, the second building unit is specifically used for:

[0029] The peak voltage of the epoxy resin to be calculated is regarded as a narrow square waveform and represented by a narrow step function. The effective value of the harmonic components of the peak voltage is calculated by combining the narrow step function with the Fourier series.

[0030] Substituting the effective value of the harmonic components of the peak voltage into the superposition expression of dielectric loss under different harmonic voltages, we obtain the expression for the dielectric loss under the peak voltage excitation. Then, we divide the expression for the dielectric loss under the peak voltage excitation into two parts and calculate the difference between them to obtain the final expression for the dielectric loss.

[0031] Optionally, the expression for the total loss of the insulating medium is:

[0032] In the formula, P total P is the total dielectric loss, where P is the dielectric loss under the high-frequency square wave voltage excitation. a P represents the dielectric loss under the peak voltage excitation. ST The additional dielectric loss is given by r, the correction coefficient is given by m, the ratio of the peak voltage amplitude to the high-frequency square wave amplitude is given by d(k), the coefficient depends on k is given by q(k), and k is a positive integer. c f is the cutoff frequency. s The frequency of the high-frequency square wave is given by C0, where C0 is the vacuum capacitor and V is the voltage. sq ε″ represents the amplitude of the high-frequency square wave, and ε″ represents the imaginary part of the complex permittivity.

[0033] A third aspect of this application provides a device for calculating insulating dielectric loss, the device comprising a processor and a memory:

[0034] The memory is used to store program code and transmit the program code to the processor;

[0035] The processor is configured to execute the steps of the method for calculating the insulation dielectric loss as described in the first aspect above, according to the instructions in the program code.

[0036] A fourth aspect of this application provides a computer-readable storage medium for storing program code for executing the method for calculating insulation dielectric loss described in the first aspect above.

[0037] As can be seen from the above technical solutions, this application has the following advantages:

[0038] This application provides a method for calculating the dielectric loss of the epoxy resin. First, the high-frequency square wave voltage of the epoxy resin under the calculation is represented by a step response function, and an expression for the dielectric loss under high-frequency square wave voltage excitation is constructed by combining Fourier series. Next, the peak voltage of the epoxy resin under the calculation is represented by a narrow step function, and an expression for the dielectric loss under peak voltage excitation is constructed by combining Fourier series. Then, the additional dielectric loss when the spectra of the high-frequency square wave voltage and the peak voltage overlap is calculated by a finite-order summation method. Finally, the additional dielectric loss and the dielectric loss of the high-frequency square wave voltage and the peak voltage are superimposed to obtain the expression for the total dielectric loss, which is used to calculate the dielectric loss of epoxy resin insulation under non-sinusoidal conditions.

[0039] Compared with existing technologies, this application studies the calculation of high-frequency insulating dielectric losses by analyzing the losses of high-frequency square waves with peak voltages. An equivalent step function to the superposition of peak voltages is proposed for quantitative calculation of the dielectric loss of epoxy resin. A cutoff frequency (fc) is defined to characterize high dV / dt characteristics. A similar narrow step function is used to simulate peak voltages at rising / falling edges. This application is of great significance for the accurate calculation of epoxy resin insulation losses under non-sinusoidal voltages. Attached Figure Description

[0040] Figure 1 is a flowchart illustrating a method for calculating insulation dielectric loss provided in an embodiment of this application;

[0041] Figure 2 shows the high-frequency bipolar non-sinusoidal waveform actually experienced by the insulating medium in the embodiments of this application;

[0042] Figure 3 shows an approximation of the low-pass step function provided in the embodiments of this application for waveform simulation;

[0043] Figure 4 shows a simulation of the spike waveform when calculating the additional dielectric loss caused by the spike in the embodiment of this application.

[0044] Figure 5 is a schematic diagram of the structure of an insulation dielectric loss calculation system provided in an embodiment of this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0046] Please refer to Figure 1. An embodiment of this application provides a method for calculating insulating dielectric loss, including:

[0047] Step 101: The high-frequency square wave voltage of the epoxy resin to be calculated is represented by the step response function, and the expression of the insulation dielectric loss under high-frequency square wave voltage excitation is constructed by combining the Fourier series.

[0048] It should be noted that, for the calculation of epoxy resin insulation dielectric loss under square wave conditions in this application, the actual voltage borne by the epoxy resin insulation dielectric at high frequencies is not ideal, as shown in Figure 2. When only a uniform and isothermal dielectric is placed between the two electrodes, and the applied voltage on the dielectric is a non-sinusoidal voltage (bipolar square wave and spike), the dielectric loss can be expressed as the superposition of dielectric losses under different harmonic voltages. The superposition expression for dielectric loss is as follows:

[0049] In the formula, C0 is the vacuum capacitance (calculated using ε0), V n,RMS This is the effective value of the nth harmonic of the applied voltage.

[0050] In one embodiment, step 101 specifically includes:

[0051] Step 1011: The high-frequency square wave voltage of the epoxy resin to be calculated is represented by the step response function of the low-pass filter, and the effective value of the harmonic components of the high-frequency square wave voltage is obtained by combining the step response function and Fourier series.

[0052] It should be noted that since the insulation in a high-frequency transformer generally withstands a high-frequency square wave voltage, and the square wave in actual applications is often not ideal, with a certain curvature in its rising and falling edges, in order to make the calculation results more consistent with the actual situation, this application uses the step response of a low-pass filter to approximate the actual square wave (the high-frequency square wave voltage of the epoxy resin to be calculated), as shown in Figure 3.

[0053] This application describes the step response function of a first-order low-pass filter using a transfer function:

[0054] In the formula, t is the rise time from 10% to 90%, G(f) is the transfer function, and f c This is the cutoff frequency.

[0055] Based on the Fourier transform, the effective value of the harmonic components of the actual square wave voltage can be calculated as follows:

[0056] In the formula, n is the harmonic order, and V sq f is the amplitude of the square wave. s The frequency is the square wave frequency.

[0057] Step 1012: Substitute the effective value of the harmonic components of the high-frequency square wave voltage into the superposition expression of dielectric loss under different harmonic voltages to obtain the expression of dielectric loss under high-frequency square wave voltage excitation. Correct the expression of dielectric loss by introducing a correction coefficient to obtain the final expression of dielectric loss.

[0058] It should be noted that, combined with Fourier series, the effective values ​​of the harmonic components of the actual square wave voltage can be calculated. Then, substituting these effective values ​​into the superposition expression for dielectric loss under different harmonic voltages yields the expression for dielectric loss under high-frequency square wave excitation. The expression for dielectric loss under high-frequency square wave excitation is as follows:

[0059] In the formula, f s Let n be the frequency of the square wave and n be the harmonic order.

[0060] Since the harmonic order is infinitely large, P′ can be approximately calculated as follows:

[0061] P′ can be finally calculated as follows:

[0062] Since the discrete superposition value of the Fourier components is slightly higher than the continuous integral value, the above approximate calculation process will introduce some errors. To eliminate these errors, this application introduces a correction coefficient r, then P can be expressed as:

[0063] This application takes into account that the electric field distribution inside the transformer is not uniform, so the final expression for the dielectric loss P can be expressed as:

[0064] In the formula, ε0 is the vacuum permittivity, ε″ is the imaginary part of the complex permittivity, and E sq This represents the magnitude of the electric field strength under a square wave voltage.

[0065] Step 102: The peak voltage of the epoxy resin to be calculated is represented by a narrow step function, and an expression for the dielectric loss of the insulation under peak voltage excitation is constructed by combining Fourier series.

[0066] In one embodiment, step 102 specifically includes:

[0067] Step 1021: Treat the peak voltage of the epoxy resin to be calculated as a narrow square waveform and represent it through a narrow step function. Combine the narrow step function with Fourier series to calculate the effective value of the harmonic components of the peak voltage.

[0068] It should be noted that the waveform acting on the insulating medium is generally a square wave with spikes. To calculate the additional dielectric loss caused by the spike voltage, this application uses a similar narrow step function simulation method, as shown in Figure 4. The spike voltage is considered as a narrow square waveform, equivalent to the magnified spike voltage in Figure 3. A Fourier transform is also required on the approximate spike waveform. The maximum effective value of each harmonic component can be obtained as follows:

[0069] In the formula, m is the ratio of the peak voltage amplitude to the square wave amplitude, T0 is one-hundredth of the square wave period, kT0 is the duration of the peak voltage, and T... s For a square wave with period φ n =π / 2-πnkT0 / T s This is a harmonic phase shift.

[0070] Step 1022: Substitute the effective value of the harmonic components of the peak voltage into the superposition expression of dielectric loss under different harmonic voltages to obtain the expression for dielectric loss under peak voltage excitation. Then, divide the expression for dielectric loss under peak voltage excitation into two parts and calculate them separately to obtain the final expression for dielectric loss.

[0071] It should be noted that after obtaining the effective value, the expression for the dielectric loss under peak voltage excitation can be obtained by following the method in step 1012 above:

[0072] Because directly to P a The calculation derivation is quite difficult, therefore this application will use P. a P' represents the difference between the two parts, i.e.: P' a =P′ a1 -P′ a2 ;

[0073] Among them, P a1 ′ can be represented as:

[0074] Using the same method, we obtain P. a1 The final expression for ′ is:

[0075] In the formula, ln(T0f c1 ) and ln(f c / f s All of these are coefficients of the step response function of the low-pass filter, therefore it is assumed that ln(T0f) is the same as the coefficient of the step response function of the low-pass filter. c1 ) and ln(f c / f s )equal.

[0076] P a2 ′ can be represented as:

[0077] P a2 The result can be approximated by performing a finite number of summs using computational software, yielding the following result:

[0078] In the formula, q(k) is the coefficient related to k. When k is 1, 2, 3, 4 and 5, q(k) is 2.83, 2.09, 1.68, 1.39 and 1.16 respectively.

[0079] Therefore, P a ′ can be represented as:

[0080] Step 103: Calculate the additional dielectric loss when the spectra of the high-frequency square wave voltage and the peak voltage overlap using a finite summation method.

[0081] It should be noted that since the rise time of the square wave and the voltage spike is the same, their spectra overlap. The additional dielectric loss cannot be ignored and can be expressed as:

[0082] In the formula, V s,n,RMS V is the effective value of the nth harmonic in the square wave voltage. T,n,RMS It is the conjugate complex number of the effective value of the nth harmonic in the peak voltage.

[0083] Combining the above relevant equations, P ST ′ can be represented as:

[0084] P ST The result can be approximated by performing a finite number of summs using computational software, yielding the following result:

[0085] In the formula, d(k) is a coefficient that depends on k. When k is 1, 2, 3, 4 and 5, d is 0.603, 0.696, 0.707, 0.709 and 0.710 respectively.

[0086] Step 104: Superimpose the additional dielectric loss and the dielectric loss of the high-frequency square wave voltage and the peak voltage to obtain the expression for the total dielectric loss, which is used to calculate the dielectric loss of epoxy resin insulation under non-sinusoidal conditions.

[0087] It should be noted that the insulation dielectric loss of the high-frequency square wave voltage obtained in step 101, the insulation dielectric loss of the peak voltage obtained in step 102, and the additional dielectric loss obtained in step 10 are superimposed to obtain the expression for the total insulation dielectric loss, which is used to calculate the epoxy resin insulation dielectric loss under non-sinusoidal conditions.

[0088] The expression for the total loss of the insulating medium is:

[0089] In the formula, P total P is the total dielectric loss, where P is the dielectric loss under high-frequency square wave voltage excitation. a For the dielectric loss of the insulation under peak voltage excitation, P ST For additional dielectric loss, r is the correction coefficient, m is the ratio of peak voltage amplitude to high-frequency square wave amplitude, d(k) is a coefficient dependent on k, q(k) is a coefficient related to k, k is a positive integer, and f c f is the cutoff frequency. s The frequency of the high-frequency square wave is given by C0, where C0 is the vacuum capacitor and V is the voltage. sq ε″ represents the amplitude of the high-frequency square wave, and ε″ represents the imaginary part of the complex permittivity.

[0090] The above is a method for calculating insulation dielectric loss provided in the embodiments of this application. The following is a system for calculating insulation dielectric loss provided in the embodiments of this application.

[0091] Please refer to Figure 5. An embodiment of this application provides a system for calculating insulating dielectric loss, comprising:

[0092] The first building unit 201 is used to represent the high-frequency square wave voltage of the epoxy resin to be calculated through the step response function, and to construct an expression for the insulation dielectric loss under high-frequency square wave voltage excitation by combining Fourier series.

[0093] The second building unit 202 is used to represent the peak voltage of the epoxy resin to be calculated through a narrow step function, and to construct an expression for the insulation dielectric loss under peak voltage excitation by combining Fourier series.

[0094] The first calculation unit 203 is used to calculate the additional dielectric loss when the spectra of high-frequency square wave voltage and peak voltage overlap by a finite summation method.

[0095] The second calculation unit 204 is used to superimpose the additional dielectric loss, as well as the insulation dielectric loss of the high-frequency square wave voltage and the peak voltage, to obtain the expression for the total insulation dielectric loss, which is used to calculate the epoxy resin insulation dielectric loss under non-sinusoidal conditions.

[0096] Furthermore, this application embodiment also provides a computing device for insulating dielectric loss, the device including a processor and a memory:

[0097] The memory is used to store program code and transmit the program code to the processor;

[0098] The processor is used to execute the steps of the insulation dielectric loss calculation method as described in the above method embodiments, according to the instructions in the program code.

[0099] Furthermore, this application embodiment also provides a computer-readable storage medium for storing program code for executing the methods described in the above method embodiments.

[0100] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0101] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0102] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0106] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0107] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

A method for calculating the loss of an insulating medium, characterized in that, The method comprises the steps of: representing the high-frequency square wave voltage in which the epoxy resin to be calculated is located by a step response function, and combining a Fourier series to construct an expression of the dielectric loss under the high-frequency square wave voltage excitation; representing the sharp peak voltage in which the epoxy resin to be calculated is located by a narrow step function, and combining a Fourier series to construct an expression of the dielectric loss under the sharp peak voltage excitation; calculating the additional dielectric loss when the frequency spectrum of the high-frequency square wave voltage and the sharp peak voltage overlaps by a limited summation method; superimposing the additional dielectric loss and the dielectric losses of the high-frequency square wave voltage and the sharp peak voltage to obtain an expression of the total dielectric loss, which is used to calculate the dielectric loss of the epoxy resin under non-sinusoidal conditions. The method of claim 1, wherein the insulating medium loss is calculated by: The expression of the dielectric loss under the high-frequency square wave voltage excitation is constructed by representing the high-frequency square wave voltage in which the epoxy resin to be calculated is located by a step response function and combining a Fourier series, and specifically comprises the steps of: representing the high-frequency square wave voltage in which the epoxy resin to be calculated is located by a step response function of a low-pass filter, and combining the step response function and a Fourier series to obtain the effective value of the harmonic component of the high-frequency square wave voltage; substituting the effective value of the harmonic component of the high-frequency square wave voltage into a superimposed expression of the dielectric loss under different harmonic voltages to obtain the expression of the dielectric loss under the high-frequency square wave voltage excitation, and correcting the expression of the dielectric loss by introducing a correction coefficient to obtain the final expression of the dielectric loss. The method for calculating dielectric loss according to claim 1 is characterized in that, The expression of the dielectric loss under the sharp peak voltage excitation is constructed by representing the sharp peak voltage in which the epoxy resin to be calculated is located by a narrow step function and combining a Fourier series, and specifically comprises the steps of: regarding the sharp peak voltage in which the epoxy resin to be calculated is located as a narrow square wave and representing it by a narrow step function, and combining the narrow step function and a Fourier series to obtain the effective value of the harmonic component of the sharp peak voltage; substituting the effective value of the harmonic component of the sharp peak voltage into a superimposed expression of the dielectric loss under different harmonic voltages to obtain the expression of the dielectric loss under the sharp peak voltage excitation, and calculating the difference between the two parts after the expression of the dielectric loss under the sharp peak voltage excitation is divided into two parts to obtain the final expression of the dielectric loss. The method of claim 1, wherein the insulating medium loss is calculated by: The total loss expression of the insulating medium is: where P total is the total loss of the dielectric, P is the loss of the dielectric under the high-frequency square-wave voltage excitation, P a is the loss of the dielectric under the peak voltage excitation, P ST is the additional dielectric loss, r is a correction factor, m is the ratio of the peak voltage amplitude to the high-frequency square-wave amplitude, d(k) is a coefficient dependent on k, q(k) is a coefficient related to k, k is a positive integer, f c is the cut-off frequency, f s is the frequency of the high-frequency square wave, C0 is the vacuum capacitance, V sq is the amplitude of the high-frequency square wave, and ε" is the imaginary part of the complex dielectric constant. A system for calculating the loss of an insulating medium, characterized in that The method comprises the steps of: a first construction unit is configured to represent the high-frequency square wave voltage in which the epoxy resin to be calculated is located by a step response function, and combine a Fourier series to construct an expression of the dielectric loss under the high-frequency square wave voltage excitation; a second construction unit is configured to represent the sharp peak voltage in which the epoxy resin to be calculated is located by a narrow step function, and combine a Fourier series to construct an expression of the dielectric loss under the sharp peak voltage excitation; a first calculation unit is configured to calculate the additional dielectric loss when the frequency spectrum of the high-frequency square wave voltage and the sharp peak voltage overlaps by a limited summation method; a second calculation unit is configured to superimpose the additional dielectric loss and the dielectric losses of the high-frequency square wave voltage and the sharp peak voltage to obtain an expression of the total dielectric loss, which is used to calculate the dielectric loss of the epoxy resin under non-sinusoidal conditions. The system for calculating dielectric loss according to claim 5, wherein The first construction unit is specifically used for: The high-frequency square wave voltage where the epoxy resin to be calculated is located is represented by a step response function of a low-pass filter, and the effective value of the harmonic component of the high-frequency square wave voltage is calculated by combining the step response function and a Fourier series; The effective value of the harmonic component of the high-frequency square wave voltage is substituted into a dielectric loss superposition expression under different harmonic voltages to obtain an expression of the dielectric loss under the high-frequency square wave voltage excitation, the expression of the dielectric loss is corrected by introducing a correction coefficient to obtain a final expression of the dielectric loss. The system for calculating dielectric loss according to claim 5, wherein, The second construction unit is specifically used for: The peak voltage where the epoxy resin to be calculated is located is regarded as a narrow square wave form and is represented by a narrow step function, and the effective value of the harmonic component of the peak voltage is calculated by combining the narrow step function and a Fourier series; The effective value of the harmonic component of the peak voltage is substituted into a dielectric loss superposition expression under different harmonic voltages to obtain an expression of the dielectric loss under the peak voltage excitation, and the expression of the dielectric loss under the peak voltage excitation is divided into two parts and the difference is calculated to obtain a final expression of the dielectric loss. The system for calculating dielectric loss according to claim 5, wherein The total loss expression of the insulating medium is: where P total is the total dielectric loss, P is the dielectric loss under the high-frequency square-wave voltage excitation, P a is the dielectric loss under the peak voltage excitation, P ST is the additional dielectric loss, r is a correction factor, m is the ratio of the peak voltage amplitude to the high-frequency square-wave amplitude, d(k) is a coefficient dependent on k, q(k) is a coefficient related to k, k is a positive integer, f c is the cut-off frequency, f s is the frequency of the high-frequency square wave, C0 is the vacuum capacitance, V sq is the amplitude of the high-frequency square wave, and ε" is the imaginary part of the complex dielectric constant. A device for calculating the loss of an insulating medium, characterized in that The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the insulation dielectric loss calculation method according to the instructions in the program code. A computer-readable storage medium, characterized by The computer readable storage medium is used to store program code, and the program code is used to execute the insulation dielectric loss calculation method. The computer readable storage medium is used to store program code, and the program code is used to execute the insulation dielectric loss calculation method.

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