Broadband modeling method for resistance-capacitance direct-current voltage divider of direct-current voltage transformer

Abstract

The invention discloses a broadband modeling method for a resistance-capacitance direct-current voltage divider of a direct-current voltage transformer, and the method comprises the steps: constructing a resistance-capacitance primary voltage dividing loop of the direct-current voltage transformer, and calculating a transfer function H1 (s) of the primary voltage dividing loop based on the resistance and capacitance of the resistance-capacitance primary voltage dividing loop; constructing a resistance-capacitance type secondary voltage division loop of the direct-current voltage transformer, and calculating a transfer function H2 (s) of the secondary voltage division loop; determining a transfer function G (s) of an isolation filter of the DC voltage transformer; the method comprises the following steps: connecting transfer functions of three links of a primary voltage division loop, a secondary voltage division loop and an isolation filter to obtain a transfer function simulation model of the whole DC voltage transformer, simulating the transfer function H (s) of the DC voltage divider by using simulation software, performing time domain analysis based on step response, and analyzing and comparing steady-state performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of DC voltage transformers, in particular to a wideband modeling method for a resistance-capacitance type DC voltage divider of a DC voltage transformer. BACKGROUND

[0002] A DC voltage transformer (hereinafter referred to as DCTV) can accurately measure the operating voltage on a DC transmission line. The design of the DCTV is mainly aimed at DC or power frequency (50Hz), and the bandwidth is usually narrow (usually within 1000Hz). However, harmonics (especially high-frequency harmonics) can reach several thousand hertz, which is far beyond the effective measurement range of the DCTV, so that high-frequency harmonics are attenuated or filtered out, resulting in that the output on the secondary side of the DCTV cannot reflect the true harmonic content.

[0003] On the other hand, when a transient fault occurs in a power transmission system, the ground potential is lifted or high-frequency noise is coupled to the secondary side through parasitic capacitance, which pollutes the measurement signal and causes the secondary side measurement voltage of the DC voltage transformer to be unable to accurately reflect the primary side voltage signal. In the step response, the overshoot is too large or the regulation time is too long, which will cause the transient voltage to be unable to track in real time, which may cause subsequent line protection to be refused or misoperated, and affect the normal operation of the power system.

[0004] The disclosure of the above background art content is only used to assist in understanding the concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present application, nor does it necessarily provide technical teaching. In the absence of explicit evidence that the above content has been disclosed before the filing date of the present application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0005] The purpose of the present application is to provide a wideband modeling method for a resistance-capacitance type DC voltage divider of a DC voltage transformer, which uses step response to analyze the time domain characteristics of the transformer to obtain the transfer characteristics of the DC voltage transformer in the time domain.

[0006] To achieve the above purpose, the technical solutions adopted by the present application are as follows:

[0007] A wideband modeling method for a resistance-capacitance type DC voltage divider of a DC voltage transformer, comprising:

[0008] constructing a resistance-capacitance type primary voltage dividing circuit of the DC voltage transformer, and calculating a transfer function H1(s) of the primary voltage dividing circuit based on its resistance and capacitance;

[0009] constructing a resistance-capacitance type secondary voltage dividing circuit of the DC voltage transformer, and calculating a transfer function H2(s) of the secondary voltage dividing circuit based on its resistance and capacitance;

[0010] An isolation filter of a DC voltage transformer is constructed, and a transfer function G(s) thereof is determined, which is related to a cutoff frequency of the filter;

[0011] A transfer function of a DC voltage divider of the DC voltage transformer is determined as H(s)=H1(s)×H2(s)×G(s);

[0012] The transfer function H(s) of the DC voltage divider is simulated by using simulation software, and time domain data of the DC voltage divider is obtained.

[0013] Further, any one of the above technical solutions or a combination of the above technical solutions, the primary voltage dividing circuit is constructed as an equivalent circuit as follows: a first resistor and a second resistor are connected in series to form a first branch, a first capacitor is connected in parallel with the first resistor, a second capacitor is connected in parallel with the second resistor, and one end of the first branch is connected to a DC transmission line, and the other end is grounded.

[0014] Further, any one of the above technical solutions or a combination of the above technical solutions, the transfer function H1(s) of the primary voltage dividing circuit is determined in the following manner:

[0015] The voltage at one end of the first branch connected to the DC transmission line is a high-voltage side voltage u1, and the voltage at a middle connection point of the first resistor and the second resistor is a low-voltage side voltage u2, and a differential relationship is as follows:

[0016] Wherein, C1 is a capacitance value of the first capacitor, C2 is a capacitance value of the second capacitor, R1 is a resistance value of the first resistor, and R2 is a resistance value of the second resistor.

[0017] The Laplace transform is performed on the differential relationship to obtain the transfer function of the primary voltage dividing circuit:

[0018] Wherein, s is a Laplace variable.

[0019] Further, any one of the above technical solutions or a combination of the above technical solutions, the secondary voltage dividing circuit is constructed as an equivalent circuit as follows: a third resistor and a fourth resistor are connected in series to form a second branch, a third capacitor is connected in parallel with the third resistor, and one end of the second branch is connected to a low-voltage side of the primary voltage dividing circuit, and the other end is grounded.

[0020] Further, any one of the above technical solutions or a combination of the above technical solutions, the transfer function H2(s) of the secondary voltage dividing circuit is determined in the following manner: 21

[0021] ​The low-voltage side voltage of the primary voltage division circuit is the high-voltage side voltage u3 of the second branch, and the voltage at the intermediate connection point of the third resistor and the fourth resistor is the low-voltage side voltage u4, which satisfies the differential relationship as follows:

[0022] C3 is the capacitance value of the third capacitor, R3 is the resistance value of the third resistor, and R4 is the resistance value of the fourth resistor.

[0023] The Laplace transform is performed on the differential relationship to obtain the transfer function of the secondary voltage division circuit:

[0024] s is the Laplace variable.

[0025] Further, any one of the above technical solutions or a combination of the above technical solutions, the secondary voltage division circuit is constructed as an equivalent circuit as follows: the fifth resistor and the sixth resistor are connected in series to form a third branch, the fifth capacitor is connected in parallel with the fifth resistor, the sixth capacitor is connected in parallel with the sixth resistor, and one end of the third branch is connected to the low-voltage side of the primary voltage division circuit, and the other end is grounded.

[0026] Further, any one of the above technical solutions or a combination of the above technical solutions, the transfer function H 22 (s) of the secondary voltage division circuit is determined in the following manner:

[0027] The low-voltage side voltage of the primary voltage division circuit is the high-voltage side voltage u3 of the second branch, and the voltage at the intermediate connection point of the third resistor and the fourth resistor is the low-voltage side voltage u4, which satisfies the differential relationship as follows:

[0028] C5 is the capacitance value of the fifth capacitor, C6 is the capacitance value of the sixth capacitor, R5 is the resistance value of the fifth resistor, and R6 is the resistance value of the sixth resistor.

[0029] The Laplace transform is performed on the differential relationship to obtain the transfer function of the secondary voltage division circuit:

[0030]

[0031] Further, any one of the above technical solutions or a combination of the above technical solutions, the isolation filter is a second-order low-pass isolation filter, and the transfer function thereof is:

[0032] ω n is the cutoff frequency of the filter, and ξ is the damping ratio of the filter, wherein s is the Laplace variable.

[0033] Further, in combination with any of the above technical solutions or the combinations of multiple technical solutions, the wideband modeling method for the RC DC voltage divider of the DC voltage transformer further comprises:

[0034] The wideband target range of the filter cutoff frequency is preset, including a first cutoff frequency and a second cutoff frequency;

[0035] The simulation obtained time domain data includes the peak value and the steady state value of the output response of the DC voltage transformer, and the overshoots corresponding to the first cutoff frequency and the second cutoff frequency are calculated;

[0036] If the overshoot corresponding to the first cutoff frequency or the overshoot corresponding to the second cutoff frequency exceeds the preset qualified range, the RC parameters of the primary voltage dividing circuit or the secondary voltage dividing circuit are adjusted, so that the overshoots corresponding to the first cutoff frequency and the second cutoff frequency tend to the qualified range.

[0037] Further, in combination with any of the above technical solutions or the combinations of multiple technical solutions, the high-voltage side voltage of the primary voltage dividing circuit is the working voltage of the DC transmission line measured by the DC voltage transformer, the high-voltage side voltage of the secondary voltage dividing circuit is the low-voltage side voltage of the primary voltage dividing circuit, and the low-voltage side voltage of the secondary voltage dividing circuit is the power supply voltage of the isolation filter.

[0038] The technical solution provided by the application has the following beneficial effects: the transfer functions of the primary voltage dividing circuit, the secondary voltage dividing circuit and the isolation filter of the DC voltage transformer are connected to obtain a transfer function simulation model of the entire DC voltage transformer, time domain analysis is performed based on the step response, and the dynamic performance and the steady state performance of the system can be analyzed and compared. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings needed in the embodiment or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0040] Figure 1 The flowchart of the wideband modeling method for the RC DC voltage divider of the DC voltage transformer provided by an exemplary embodiment of the application is shown in the figure;

[0041] Figure 2 The structure diagram of the ultra-high voltage DC voltage transformer provided by an exemplary embodiment of the application is shown in the figure;

[0042] Figure 3Equivalent circuit diagram of a primary voltage dividing circuit of a direct current voltage transformer provided for an exemplary embodiment of the present application;

[0043] Figure 4 Equivalent circuit diagram of a type I secondary voltage dividing circuit of a direct current voltage transformer provided for an exemplary embodiment of the present application;

[0044] Figure 5 Equivalent circuit diagram of a type II secondary voltage dividing circuit of a direct current voltage transformer provided for an exemplary embodiment of the present application;

[0045] Figure 6 Simulation model schematic diagram of a resistance-capacitance type direct current voltage divider of a direct current voltage transformer provided for an exemplary embodiment of the present application;

[0046] Figure 7 Response result diagram of a type I direct current voltage transformer obtained by simulation provided for an exemplary embodiment of the present application;

[0047] Figure 8 Response result diagram of a type II direct current voltage transformer obtained by simulation provided for an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the personnel in the art better understand the present application scheme, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person of ordinary skill in the art without making creative efforts should belong to the scope of protection of the present application.

[0049] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, device, product or equipment including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.

[0050] In addition to meeting the measurement accuracy requirements for direct current voltage, the DCTV also needs to have strong wideband measurement capability to provide measurement data for harmonic control of the ultra-high voltage direct current transmission, and accurate determination of the wideband transfer characteristics of the DCTV can effectively improve the accuracy of the DCTV in measuring harmonics and transient voltages.

[0051] As shown in the structure diagram of the ultra-high voltage direct current voltage transformer, the resistance-capacitance type direct current voltage divider includes a primary voltage dividing circuit and a secondary voltage dividing circuit, and the resistance-capacitance type direct current voltage divider is a key component in the direct current voltage transformer, which realizes voltage division and high-frequency signal compensation through the combination of resistors and capacitors. Figure 2 Typically, the resistance-capacitance type direct current voltage divider is composed of a high-voltage arm and a low-voltage arm, on the one hand, the capacitor is open, and the division ratio is determined by the resistors on the high-voltage arm and the resistors on the low-voltage arm to realize direct current steady state, and on the other hand, the capacitor is turned on, and the division ratio is determined by the capacitive reactance to realize high-frequency transient state. The resistance-capacitance voltage divider at the primary voltage dividing circuit serves as a primary side sensing unit of the DCTV, and divides the high-voltage direct current (such as 800 kV) into a low-voltage signal (such as 70 V), and the resistance-capacitance voltage divider at the secondary voltage dividing circuit serves as a secondary side sensing unit of the DCTV, and further divides the low-voltage signal output by the primary side voltage dividing circuit.

[0052] In one embodiment of the present application, a wideband modeling method for a resistance-capacitance type direct current voltage divider of a direct current voltage transformer is provided, as shown in Figure 1 The modeling method includes the following steps:

[0053] constructing a resistance-capacitance type primary voltage dividing circuit of the direct current voltage transformer, and calculating a transfer function H1(s) of the primary voltage dividing circuit based on the resistors and capacitors thereof;

[0054] constructing a resistance-capacitance type secondary voltage dividing circuit of the direct current voltage transformer, and calculating a transfer function H2(s) of the secondary voltage dividing circuit based on the resistors and capacitors thereof;

[0055] constructing an isolation filter of the direct current voltage transformer, and determining a transfer function G(s) of the isolation filter, which is related to the cutoff frequency of the filter;

[0056] determining a transfer function H(s) of the direct current voltage divider of the direct current voltage transformer as H(s) = H1(s) x H2(s) x G(s);

[0057] simulating the transfer function H(s) of the direct current voltage divider by using a simulation software to obtain time domain data of the direct current voltage divider.

[0058] Figure 2 As shown in the structure diagram of the typical ultra-high voltage direct current voltage transformer circuit, in this embodiment, the element parameters of the DCTV are simplified to obtain an equivalent circuit of the primary voltage dividing circuit as Figure 3As shown: the first resistance (the equivalent resistance on the high-voltage arm), the second resistance (the equivalent resistance on the low-voltage arm) are connected in series to form a first branch, the first capacitor (the equivalent capacitor on the high-voltage arm) is connected in parallel with the first resistance, the second capacitor (the equivalent capacitor on the low-voltage arm) is connected in parallel with the second resistance, and one end of the first branch is connected to a DC transmission line (such as 800 kV), and the other end is grounded.

[0059] Based on the equivalent circuit of Figure 3 , the transfer function H1(s) of the primary voltage dividing circuit is determined:

[0060] The voltage at one end of the first branch connected to the DC transmission line is the high-voltage side voltage u1 (such as 800 kV), and the voltage at the middle connection point of the first resistance and the second resistance is the low-voltage side voltage u2 (such as 70 V), which satisfies the differential relationship as follows:

[0061] Where C1 is the capacitance value of the first capacitor, C2 is the capacitance value of the second capacitor, R1 is the resistance value of the first resistance, and R2 is the resistance value of the second resistance.

[0062] Taking Laplace transform of the differential relationship, the transfer function of the primary voltage dividing circuit is obtained:

[0063] Where s is the Laplace variable.

[0064] In the first embodiment, the equivalent circuit of the secondary voltage dividing circuit is as shown in Figure 4 , which is called I-type secondary voltage dividing circuit: the third resistance (the equivalent resistance on the high-voltage arm), the fourth resistance (the equivalent resistance on the low-voltage arm) are connected in series to form a second branch, the third capacitor (the equivalent capacitor on the high-voltage arm) is connected in parallel with the third resistance, and one end of the second branch is connected to the low-voltage side of the primary voltage dividing circuit (i.e. the low-voltage side voltage u2 mentioned above), and the other end is grounded.

[0065] Based on the equivalent circuit of Figure 4 , the transfer function H 21 (s) of the secondary voltage dividing circuit is determined:

[0066] The low-voltage side voltage of the primary voltage dividing circuit is the high-voltage side voltage u3 of the second branch, and the voltage at the middle connection point of the third resistance and the fourth resistance is the low-voltage side voltage u4, which satisfies the differential relationship as follows:

[0067] Where C3 is the capacitance value of the third capacitor, R3 is the resistance value of the third resistance, and R4 is the resistance value of the fourth resistance.

[0068] Taking Laplace transform of the differential relationship, the transfer function of the secondary voltage dividing circuit is obtained:

[0069] Where s is the Laplace variable.

[0070] In the second embodiment, the equivalent circuit of the secondary voltage divider circuit is as follows: Figure 5 As shown, the following is referred to as a Type II secondary voltage divider circuit: the fifth resistor (equivalent resistance on the high voltage arm) and the sixth resistor (equivalent resistance on the low voltage arm) are connected in series to form the third branch. The fifth capacitor (equivalent capacitance on the high voltage arm) is connected in parallel with the fifth resistor, and the sixth capacitor (equivalent capacitance on the low voltage arm) is connected in parallel with the sixth resistor. One end of the third branch is connected to the low voltage side of the primary voltage divider circuit (i.e., the low voltage side voltage u2 mentioned above), and the other end is grounded.

[0071] based on Figure 5 The equivalent circuit is used to determine the transfer function H of the secondary voltage divider circuit. 22 (s):

[0072] Taking the low-voltage side voltage of the primary voltage divider circuit as the high-voltage side voltage u5 of the third branch, and the voltage at the midpoint connection between the fifth and sixth resistors as the low-voltage side voltage u6, the differential relationship is as follows:

[0073] Where C5 is the capacitance of the fifth capacitor, C6 is the capacitance of the sixth capacitor, R5 is the resistance of the fifth resistor, and R6 is the resistance of the sixth resistor.

[0074] Performing a Laplace transform on the differential equation yields the transfer function of the second-order voltage divider circuit:

[0075]

[0076] In this embodiment, the isolation filter is a second-order low-pass isolation filter, and its transfer function is:

[0077] Where, ω n Let ξ be the cutoff frequency of the filter, ξ be the damping ratio of the filter (typically 0.707), and s be the Laplace variable.

[0078] The comprehensive transfer function of the DC voltage transformer is obtained by multiplying the transfer functions of the primary voltage divider circuit, the secondary voltage divider circuit, and the isolation filter. Based on this, the time-domain characteristics of the transformer are analyzed using the step response to obtain the time-domain transmission characteristics of the DC voltage transformer. In one embodiment, each component of the RC DC voltage divider is modeled separately in MATLAB software. The transfer functions of the primary voltage divider circuit, the secondary voltage divider circuit, and the isolation filter are connected to obtain the simulation model of the transfer function of the entire DC voltage transformer.

[0079] The comprehensive transfer function of a type I DC voltage transformer is H. Ⅰ =H1(s)*H 21 (s)*G(s);

[0080] The comprehensive transfer function of the type II DC voltage transformer is H. Ⅱ =H1(s)*H 22 (s)*G(s);

[0081] When DC voltage transformers are connected to the power grid, the secondary system protection analysis is based on the time-domain signal. Therefore, by performing time-domain analysis on the two types (Type I and Type II) of DC voltage transformers based on the step response, the dynamic and steady-state performance of the system can be analyzed and compared.

[0082] For a type I DC voltage transformer, its DC voltage divider includes: Figure 3 The primary voltage divider circuit and Figure 4 The secondary voltage divider circuit, the comprehensive transfer function is converted to The coefficients of the numerator and denominator are: A

[0083]

[0084] e2=(C1+C2)C3R4

[0085]

[0086] Specific numerical example 1: such as Figure 3 As shown, u1 is 800kV, u2 is 70V, R1 is 400MΩ, R2 is 34.6kΩ, C1 is 400pF, and C2 is 4600nF. Figure 4 As shown, u3 is 70V, u4 is 5V (the supply voltage of the isolation filter), R3 is 900kΩ, R4 is 75kΩ, C3 is 430pF, and the simulation model of the transfer function of the DC voltage transformer is as follows. Figure 6 The simulation path for the Type I secondary voltage divider circuit is shown below. The simulation results are as follows when the filter cutoff frequency is set to 1000Hz, 3000Hz, and 5000Hz respectively. Figure 7 As shown in Table 1, the horizontal axis represents time in seconds and the vertical axis represents voltage in volts. The step response performance indicators at the three cutoff frequencies are shown in Table 1.

[0087] Table 1 Dynamic Performance of Type I DC Voltage Transformer Step Response

[0088]

[0089] See Figure 7As shown in Table 1, the transmission characteristics of the Type I DC voltage transformer change significantly at the three filter cutoff frequencies of 1000Hz, 3000Hz and 5000Hz. In the step response, the overshoot of the transformer with a cutoff frequency of 3000Hz reaches 14.6%, and the overshoot of the DC voltage transformer with a cutoff frequency of 5000Hz even reaches 38.6%.

[0090] Specific numerical example 2: such as Figure 3 As shown, u1 is 800kV, u2 is 70V, R1 is 400MΩ, R2 is 34.6kΩ, C1 is 400pF, and C2 is 4600nF. Figure 5 As shown, u5 is 70V, u6 is 5V (the supply voltage of the isolation filter), R5 is 900kΩ, R6 is 75kΩ, C5 is 430pF, and C6 is 5200pF. The simulation model of the transfer function of the DC voltage transformer is as follows. Figure 6 The simulation path for the Type II secondary voltage divider circuit is shown below. The simulation results are as follows: [The text abruptly ends here, so the translation stops as well.] Figure 8 As shown in Table 2, the horizontal axis represents time in seconds and the vertical axis represents voltage in volts. The step response performance indicators at the three cutoff frequencies are shown in Table 2.

[0091] Table 2 Dynamic Performance of Type II DC Voltage Transformer Step Response

[0092]

[0093] See Figure 8 As shown in Table 2, the overshoot of the Type II DC voltage transformer in the step response is within 5% at the cutoff frequencies of the three filters: 1000Hz, 3000Hz, and 5000Hz. Regarding rise time, the rise time of the DC voltage transformer is significantly affected by the cutoff frequency of the isolation filter; the higher the cutoff frequency, the shorter the rise time and the faster the response.

[0094] As can be seen, compared with the specific numerical embodiment 1, the DC voltage transformer in the specific numerical embodiment 2 has good wideband transmission characteristics and strong wideband measurement capability, which can provide accurate measurement data for harmonic control of UHVDC transmission.

[0095] In one embodiment of the present invention, the wideband modeling method for a resistive-capacitive DC voltage divider further includes:

[0096] The target wideband range of the filter cutoff frequency is preset, for example, 1000Hz to 3000Hz;

[0097] The time domain data obtained by simulation includes the peak value and the steady value of the output response of the DC voltage transformer, and the overshoot of the transformer in the step response corresponding to the cut-off frequency 1000 Hz and the cut-off frequency 3000 Hz is calculated;

[0098] If the overshoot corresponding to 1000 Hz or the overshoot corresponding to 3000 Hz exceeds the preset qualified range, the resistance-capacitance parameters of the primary voltage dividing circuit or the secondary voltage dividing circuit are adjusted so that the overshoots corresponding to 1000 Hz and 3000 Hz tend to the qualified range. For example, for the specific numerical embodiment 1, the overshoot of the transformer in the step response at the cut-off frequency 3000 Hz obtained by simulation under the current resistance-capacitance parameters exceeds the qualified threshold 5%, then all or part of the values of R1, R2, C1, C2, R3, R4 and C3 can be adjusted so that the simulation result after adjusting the resistance-capacitance parameters reaches the preset target.

[0099] It should be noted that the relational terms herein such as first and second are used only to differentiate one entity or action from another, and do not necessarily require or imply that any such actual relationship or order exists between or among the entities or actions. Also, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not necessarily contain only those elements, but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0100] The above is only a specific embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A method of wideband modeling of a resistive-capacitive DC voltage divider of a DC voltage transformer, characterized in that, The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer.

2. The method of claim 1, wherein, The application relates to a method for simulating a transfer function of a DC voltage transformer.

3. The method of claim 2, wherein, The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. wherein C1 is a capacitance value of the first capacitor, C2 is a capacitance value of the second capacitor, R1 is a resistance value of the first resistor, and R2 is a resistance value of the second resistor. The application relates to a method for simulating a transfer function of a DC voltage transformer. where s is the Laplacian variable.

4. The method of claim 2, wherein the method is a wideband modeling method of a resistive-capacitive DC voltage divider of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer.

5. The RC divider broadband modeling method of a DC voltage transformer according to claim 4, wherein, The transfer function H of the secondary voltage division circuit is determined by 21 (s): The application relates to a method for simulating a transfer function of a DC voltage transformer. C3R3+ R4where C3is a capacitance value of the third capacitor, R3is a resistance value of the third resistor, and R4is a resistance value of the fourth resistor. The application relates to a method for simulating a transfer function of a DC voltage transformer. where s is the Laplacian variable.

6. The RC divider broadband modeling method of a DC voltage transformer according to claim 2, wherein, The application relates to a method for simulating a transfer function of a DC voltage transformer.

7. The RC divider broadband modeling method of a DC voltage transformer according to claim 6, characterized in that, The transfer function H of the secondary voltage division circuit is determined by 22 (s): The application relates to a method for simulating a transfer function of a DC voltage transformer. wherein C5 is a capacitance value of the fifth capacitor, C6 is a capacitance value of the sixth capacitor, R5 is a resistance value of the fifth resistor, and R6 is a resistance value of the sixth resistor. The application relates to a method for simulating a transfer function of a DC voltage transformer.

8. The method of claim 1, wherein, The application relates to a method for simulating a transfer function of a DC voltage transformer. where ωc n is the cutoff frequency of the filter and ξ is the damping ratio of the filter, where s is the Laplace variable.

9. The RC divider broadband modeling method of a DC voltage transformer according to any one of claims 1 to 8, characterized in that, The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. 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The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a DC voltage transformer. The application relates to a method for simulating a transfer function of a If the overshoot corresponding to the first cutoff frequency or the overshoot corresponding to the second cutoff frequency is out of the preset qualified range, the resistance-capacitance parameters of the primary voltage division circuit or the secondary voltage division circuit are adjusted so that the overshoots corresponding to the first cutoff frequency and the second cutoff frequency tend to the qualified range.

10. The RC divider broadband modeling method of a DC voltage transformer according to any one of claims 1 to 8, characterized in that, The high-voltage side voltage of the primary voltage division circuit is the working voltage of the DC power transmission line measured by the DC voltage transformer, the high-voltage side voltage of the secondary voltage division circuit is the low-voltage side voltage of the primary voltage division circuit, and the low-voltage side voltage of the secondary voltage division circuit is the power supply voltage of the isolation filter.

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