Capacitive voltage transformer broadband characteristic analysis method, system and device and medium

Abstract

The invention discloses a capacitive voltage transformer broadband characteristic analysis method, system, equipment and medium, and belongs to the technical field of capacitive voltage transformer error characteristic analysis, and the method comprises the steps: obtaining basic parameters of a capacitive voltage transformer, and obtaining stray parameters of high-voltage arm capacitance and turn-to-turn distribution capacitance; calculating parameters of a four-capacitor distributed model through basic parameters of a primary side and a secondary side of the transformer, and calculating parameters of a resistance-capacitance matching module through an actual line simulation condition; and carrying out broadband characteristic research in combination with all the parameters, carrying out parameter optimization of the capacitive transformer in an auxiliary manner, and outputting the transformer parameters according to the broadband characteristic to be obtained if the resonance point simulation result meets the expectation. According to the method, an objective data basis is provided, accurate conversion from a physical model to a computable mathematical model is realized, broadband characteristics of the CVT are analyzed in a high-precision manner, the precision of a high-frequency model is remarkably improved, meanwhile, the method has engineering practicability, and a key design and optimization basis can be provided for development of the high-performance CVT.

Description

Technical Field

[0001] This invention relates to the field of error characteristic analysis technology for capacitive voltage transformers, specifically to a method, system, device, and medium for wideband characteristic analysis of capacitive voltage transformers. Background Technology

[0002] Capacitive voltage transformers (CVTs), as crucial voltage sensing devices in high-voltage power grids, have been widely used in power systems due to their unique advantages. In power frequency measurement, CVTs can accurately reflect the amplitude and phase information of the grid voltage, providing reliable data support for the normal operation and dispatch of the power system. In recent years, with the development of electronic power grids, the demand for wide-frequency voltage measurement (above 10kHz) has become increasingly urgent. However, due to inherent structural limitations, traditional CVTs suffer from significant distortion in their wide-frequency transmission characteristics, posing a severe challenge to high-precision measurement.

[0003] The national standard GBT 14549-1993 "Power Quality - Harmonics in Public Power Grids" and international standards for transformers clearly stipulate that CVTs are not suitable for harmonic measurement. However, in actual engineering, engineers still have to rely on CVTs to obtain harmonic data. Therefore, how to evaluate and analyze the wideband characteristics of capacitive voltage transformers is a current research hotspot.

[0004] Currently, the mainstream technical solutions for wideband characteristic analysis of capacitive voltage transformers (CVTs) fall into two categories. One is based on a high-frequency generalization model, which uses a high-frequency generalization model of resistance, inductance, and capacitance as a wideband model for resistive, inductive, and capacitive components. An intelligent optimization algorithm is then used to calculate the specific parameters of each component in the model. This method ensures that the model is microscopic and passive, but it cannot be used for wideband modeling of transformer-type two-port devices. The other common method is based on a three-capacitor CVT equivalent model, which requires consideration of parameters such as voltage divider capacitors, compensating reactors, inter-turn distributed capacitance, and equivalent leakage inductance, and parameter modeling is performed experimentally. The experimental modeling accuracy of the above methods cannot yet meet the requirements of wideband voltage measurement in modern power systems. Summary of the Invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, this invention aims to solve problems such as rough matching between stray parameters and physical structure, and neglecting the influence of the circuit.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for analyzing the broadband characteristics of a capacitive voltage transformer, comprising, Obtain the basic parameters of the capacitive voltage transformer, and obtain the stray parameters of the high-voltage arm capacitance and inter-turn distributed capacitance; calculate the parameters of the four-capacitor distributed model using the basic parameters of the transformer primary and secondary sides, and calculate the parameters of the RC matching module using actual line simulation; combine all parameters to study the broadband characteristics, and assist in optimizing the parameters of the capacitive voltage transformer; if the simulation results of the resonant point meet the expectations, output the transformer parameters according to the desired broadband characteristics.

[0008] As a preferred embodiment of the broadband characteristic analysis method for a capacitive voltage transformer described in this invention, the basic parameters include those obtained through open-circuit / short-circuit tests, frequency sweep tests, and those provided by the manufacturer. These parameters include the equivalent series resistance of the voltage divider capacitor, the equivalent series resistance and parallel capacitance of the compensation reactor, the inter-turn distributed capacitance of the primary and secondary windings of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the secondary winding of the transformer, the equivalent distributed capacitance of the primary and secondary windings, the equivalent magnetizing resistance and magnetizing inductance of the transformer, the equivalent resistance and equivalent inductance of the damper referred to the primary winding, and the equivalent resistance and equivalent inductance of the load referred to the primary winding.

[0009] As a preferred embodiment of the wideband characteristic analysis method for a capacitive voltage transformer described in this invention, the stray parameters include high-frequency stray inductance and distributed capacitance. Using an impedance analyzer, the port impedance is scanned and measured over a wide frequency range. First resonant point and inductive reactance In the resistive region, the impedance increases linearly. By fitting the impedance of the current linear segment, the high-frequency stray inductance can be obtained. ; By short-circuiting the beginning and end of the high-voltage winding using the short-circuit-open-circuit method, the capacitance to ground at this short-circuit point is measured. Suspend the end of the high-voltage winding and measure the capacitance between the beginning and ground. Collect the distributed capacitance of the damper inductance. ≈ ² / .

[0010] As a preferred embodiment of the wideband characteristic analysis method for capacitive voltage transformers described in this invention, the calculation of the parameters of the four-capacitor distributed model includes representing all components in impedance form according to the circuit model: in, and These are the equivalent series resistances of the voltage divider capacitors. and To compensate for the equivalent series resistance and equivalent parallel capacitance of the reactor, and These are the distributed capacitance between the turns on the primary side of the transformer and the distributed capacitance between the turns on the secondary side converted to the primary side, respectively. and These are the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, respectively. and These are the equivalent magnetizing resistance and magnetizing inductance of the transformer, respectively. and These are the equivalent resistance and equivalent inductance of the damper referred to the primary side, respectively. and These are the equivalent resistance and equivalent inductance of the load referred to the primary side, respectively. and These are voltage divider capacitors. and This is the equivalent series inductance of the voltage divider capacitor. To compensate for the equivalent series inductance of the reactor, The impedance is the distributed capacitance of the primary side. The impedance is the impedance of the transformer secondary-side inter-turn distributed capacitance referred to the primary side. The impedance is the equivalent distributed capacitance between the primary and secondary sides of the transformer. Let be the equivalent parallel capacitance of the damper referred to the primary side, and s be the complex frequency variable in the Laplace transform. and The impedance of the voltage divider capacitor branch is... To compensate for the impedance of the reactor, For the excitation branch impedance, This is the equivalent impedance of the transformer's leakage inductance and copper loss. The damper impedance, This is the load impedance.

[0011] As a preferred embodiment of the broadband characteristic analysis method for capacitive voltage transformers described in this invention, the calculation of the four-capacitor distributed model parameters further includes transforming the delta connection formed by the transformer inter-turn distributed capacitance, transformer leakage inductance, and copper loss resistance into a star connection to obtain the voltage transfer function. : Where N is the transformer turns ratio, and K is the CVT rated turns ratio. Input voltage, For output voltage, , , , It is the equivalent impedance after star connection transformation.

[0012] As a preferred embodiment of the wideband characteristic analysis method for capacitive voltage transformers described in this invention, the parameters of the calculated resistance-capacitance matching module include calculations based on the actual parameters of the secondary cable used in the actual field, such as cable type, nominal cross-section, and measured length, according to the unit length parameter.

[0013] As a preferred embodiment of the wideband characteristic analysis method for capacitive voltage transformers described in this invention, the parameter optimization includes, according to the transfer function formula... If the number and location of the resonant points in the simulation results and the experimental curves of the four capacitors are the same, then the requirements are met. If it does not meet the requirements, the parameters are obtained again, and the parameters are adjusted or reduced based on empirical rules to optimize the parameters.

[0014] Another objective of this invention is to provide a wideband characteristic analysis system for capacitive voltage transformers.

[0015] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a wideband characteristic analysis system for capacitive voltage transformers, comprising: a parameter acquisition module and a parameter optimization module; The parameter acquisition module acquires the basic parameters of the capacitive voltage transformer, as well as the stray parameters of the high-voltage arm capacitor and the inter-turn distributed capacitor; it calculates the parameters of the four-capacitor distributed model based on the basic parameters of the transformer primary and secondary sides, and calculates the parameters of the resistance-capacitance matching module based on the actual line simulation. The parameter optimization module combines all parameters to study wideband characteristics and assists in optimizing the parameters of the capacitive transformer. Based on the desired wideband characteristics, if the simulation results of the resonant point meet expectations, the transformer parameters are output.

[0016] The present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the described method for analyzing the broadband characteristics of a capacitive voltage transformer.

[0017] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of the method for analyzing the broadband characteristics of a capacitive voltage transformer.

[0018] The beneficial effects of this invention are as follows: This invention achieves comprehensive acquisition of electrical parameters of all core components of a CVT (voltage divider capacitors, compensating reactors, transformers, dampers, and loads); providing an indispensable, multi-dimensional data foundation for subsequent broadband model building. This achieves the beneficial effect of shifting model construction from relying on idealized assumptions to being based on objective data from actual measurements and design, thereby improving the initial accuracy of the model. By acquiring high-frequency stray parameters, particularly by using an impedance analyzer to fit high-frequency stray inductance with a wideband scan and by deriving the damper's distributed capacitance using the short-circuit-open-circuit method, accurate extraction of parasitic parameters (such as lead inductance, inter-winding capacitance, and capacitance to ground) that are easily neglected in traditional lumped-parameter models has been achieved. Its purpose is specifically to quantify the stray effects that dominate device behavior at high frequencies. This effectively captures high-frequency resonances and distortions caused by differences in physical structure (such as winding arrangement and wiring methods), solving the problem of coarse matching between stray parameters and physical structure in existing technologies.

[0019] This invention establishes a circuit model encompassing all impedance forms, systematically integrating all acquired parameters (including fundamental and stray parameters) into a unified circuit topology. This topology not only includes the equivalent series inductance on the input and output sides to represent external strays, but more importantly, it includes internal parasitic parameters such as the distributed capacitance between turns and between the primary and secondary sides of the transformer. This constructs a more refined prototype of a four-capacitor distributed model than traditional equivalent circuits, enabling the model to more realistically reflect the complex electromagnetic coupling relationships within the transformer from a physical structure perspective.

[0020] By performing a triangle-to-star impedance transformation and deriving the voltage transfer function, the complex triangular network composed of transformer leakage inductance, copper loss resistance, and distributed capacitance is transformed into a star connection that can be analyzed, thereby obtaining the overall transfer function of the system. This completes the key transformation from a physical circuit model to a computable mathematical model, enabling the direct analysis of the system's frequency response (such as resonant point, amplitude / phase frequency characteristics) through analytical expressions.

[0021] By calculating the parameters of the impedance matching module based on the actual parameters of the secondary cable, the characteristics of the actual transmission line (secondary cable) connecting the CVT and the measurement / protection device are incorporated into the model. This expands the analysis object from the isolated CVT equipment to the complete measurement system including its output link. This enables the quantitative assessment and compensation of the attenuation, distortion, and reflection effects caused by line impedance mismatch on high-frequency signal transmission, making the broadband characteristic analysis results more consistent with actual field operating conditions.

[0022] By simulating the transfer function and comparing it with experimental curves, the effectiveness of the aforementioned model was rapidly verified. Comparing the number and location of simulated and measured resonant points provides a direct assessment of whether the model's accuracy meets requirements. Furthermore, this method upgrades the analysis tool from a passive tool to an active design aid, allowing designers to adjust certain CVT parameters (such as distributed capacitance and damper parameters) in reverse, aiming for desired broadband characteristics (e.g., avoiding resonance in specific frequency bands, widening the flat response bandwidth). This supports customized CVT design and performance optimization, enabling the invention not only to analyze existing equipment but also to guide the development of new products with superior broadband response performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The above is a flowchart of a method for analyzing the broadband characteristics of a capacitive voltage transformer according to an embodiment of the present invention.

[0025] Figure 2 A high-frequency model (four capacitors) of a capacitive voltage transformer (CVT) is provided as an embodiment of the present invention for analyzing the wideband characteristics of a capacitive voltage transformer.

[0026] Figure 3 This invention provides a supplementary equivalent series inductance diagram for the input and output sides of a method for analyzing the broadband characteristics of a capacitive voltage transformer, as provided in one embodiment of the present invention.

[0027] Figure 4 A high-frequency model diagram of a four-capacitor distributed parameter CVT provided as an embodiment of the present invention for analyzing the broadband characteristics of a capacitive voltage transformer.

[0028] Figure 5 The resistor-capacitor matching diagram is provided for a method of analyzing the wideband characteristics of a capacitive voltage transformer according to an embodiment of the present invention.

[0029] Figure 6 This invention provides a method for analyzing the broadband characteristics of a capacitive voltage transformer (CVT) based on CVT theoretical calculations and experimental amplitude-frequency transmission characteristics.

[0030] Figure 7 This invention provides a method for analyzing the broadband characteristics of a capacitive voltage transformer (CVT) based on CVT theoretical calculations and experimental phase frequency transmission characteristics. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0032] Example 1, referring to Figures 1-5 This is one embodiment of the present invention, which provides a method for analyzing the broadband characteristics of a capacitive voltage transformer, including: S100. Obtain the basic parameters of the capacitive voltage transformer, and obtain the stray parameters of the high-voltage arm capacitor and the inter-turn distributed capacitor. S200: Calculate the parameters of the four-capacitor distributed model using the basic parameters of the transformer primary and secondary sides, and calculate the parameters of the resistance-capacitance matching module using the actual line simulation. S300: Combine all parameters to study wideband characteristics and assist in optimizing the parameters of capacitive transformers. Based on the desired wideband characteristics, if the simulation results of the resonant point meet expectations, the transformer parameters are output. It should be noted that existing technologies have limitations in performing broadband characteristic analysis by taking into account the equivalent series inductance of input and output, and in addressing the matching problem between the physical structure differences of the high-voltage arm capacitor and the inter-turn distributed capacitor and stray parameters.

[0033] Therefore, in order to address the aforementioned problems, through steps S100-S300, the high-frequency CVT model of the four-capacitor distributed parameters of this invention adopts modeling of the distributed capacitance of the primary and secondary sides of the intermediate transformer, the winding leakage inductance and the copper loss, which is more consistent with the actual physical structure of the transformer; and considers the modeling of the voltage divider capacitor of the RC matching module to supplement the influence of line impedance matching transmission on broadband characteristics.

[0034] Example 2, refer to Figures 1-5 This is one embodiment of the present invention, which provides a method for analyzing the broadband characteristics of a capacitive voltage transformer, including: In this embodiment of the invention, obtaining the basic parameters of the capacitive voltage transformer and the stray parameters of the high-voltage arm capacitance and inter-turn distributed capacitance in S100 includes the following steps S101-S102: S101. Basic parameters include those obtained from open-circuit / short-circuit tests, frequency sweep tests, and those provided by the manufacturer. These parameters include the equivalent series resistance of the voltage divider capacitor, the equivalent series resistance and parallel capacitance of the compensation reactor, the inter-turn distributed capacitance of the primary and secondary windings of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the secondary winding of the transformer, the equivalent distributed capacitance of the primary and secondary windings, the equivalent magnetizing resistance and magnetizing inductance of the transformer, the equivalent resistance and equivalent inductance of the damper referred to the primary winding, and the equivalent resistance and equivalent inductance of the load referred to the primary winding.

[0035] S102. Stray parameters include high-frequency stray inductance and distributed capacitance; Using an impedance analyzer, the port impedance is scanned and measured over a wide frequency range. First resonant point and inductive reactance In the resistive region, the impedance increases linearly. By fitting the impedance of the current linear segment, the high-frequency stray inductance can be obtained. ; By short-circuiting the beginning and end of the high-voltage winding using the short-circuit-open-circuit method, the capacitance to ground at this short-circuit point is measured. Suspend the end of the high-voltage winding and measure the capacitance between the beginning and ground. Collect the distributed capacitance of the damper inductance. ≈ ² / .

[0036] In this embodiment of the invention, step S200 calculates the parameters of the four-capacitor distributed model using the basic parameters of the transformer primary and secondary sides, and calculates the parameters of the resistance-capacitance matching module using the actual line simulation, including the following steps S201-S203: S201, reference Figure 1 and Figure 3 Based on the circuit model, all components are represented in impedance form: in, and These are the equivalent series resistances of the voltage divider capacitors. and To compensate for the equivalent series resistance and equivalent parallel capacitance of the reactor, and These are the distributed capacitance between the turns on the primary side of the transformer and the distributed capacitance between the turns on the secondary side converted to the primary side, respectively. and These are the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, respectively. and These are the equivalent magnetizing resistance and magnetizing inductance of the transformer, respectively. and These are the equivalent resistance and equivalent inductance of the damper referred to the primary side, respectively. and These are the equivalent resistance and equivalent inductance of the load referred to the primary side, respectively. and These are voltage divider capacitors. and This is the equivalent series inductance of the voltage divider capacitor. To compensate for the equivalent series inductance of the reactor, The impedance is the distributed capacitance of the primary side. The impedance is the impedance of the transformer secondary-side inter-turn distributed capacitance referred to the primary side. The impedance is the equivalent distributed capacitance between the primary and secondary sides of the transformer. Let be the equivalent parallel capacitance of the damper referred to the primary side, and s be the complex frequency variable in the Laplace transform. and The impedance of the voltage divider capacitor branch is... To compensate for the impedance of the reactor, For the excitation branch impedance, This is the equivalent impedance of the transformer's leakage inductance and copper loss. The damper impedance, This is the load impedance.

[0037] S202. Transform the delta connection formed by the transformer's inter-turn distributed capacitance, transformer leakage inductance, and copper loss resistance into a star connection to obtain the voltage transfer function. : Where N is the transformer turns ratio, and K is the CVT rated turns ratio. Input voltage, For output voltage, , , , It is the equivalent impedance after star connection transformation.

[0038] S203. Calculate based on the actual parameters of the secondary cable used on site, including cable type, nominal cross-section, and measured length, according to the unit length parameter.

[0039] In an embodiment of the present invention, S300 combines all parameters to study broadband characteristics and assists in optimizing the parameters of the capacitive transformer. Based on the desired broadband characteristics, if the simulation results of the resonant point meet expectations, the transformer parameters are output, including the following steps: According to the transfer function formula If the number and location of the resonant points in the simulation results and the experimental curves of the four capacitors are the same, then the requirements are met. If it does not meet the requirements, the parameters are obtained again, and the parameters are adjusted or reduced based on empirical rules to optimize the parameters.

[0040] like Figure 3 As shown, this invention uses an equivalent series inductor on the input and output sides for broadband characteristic analysis, reflecting the stray parameters of the high-voltage arm capacitance and inter-turn distributed capacitance; as... Figure 4 As shown, the high-frequency CVT model with four-capacitor distributed parameters uses a distributed four-capacitor model to represent the primary and secondary distributed capacitances, winding leakage inductance, and copper losses of the intermediate transformer; as shown... Figure 5 As shown, in the final output R L L L Add a resistor-capacitor matching module R before the load Z C Z The impedance matching module can be used to supplement the study of the impact of the line impedance matching degree on the wideband characteristics of capacitive voltage transformers.

[0041] Example 3, referring to Figure 6 and Figure 7 This invention provides a method for analyzing the broadband characteristics of a capacitive voltage transformer, and scientific demonstration is conducted through experiments to verify the beneficial effects of the invention.

[0042] Depend on Figure 6 and Figure 7 The test results show that the wideband transmission characteristics of the CVT resonated within the frequency range of 50Hz to 2.5kHz, resulting in abrupt changes in amplitude and phase.

[0043] The calculation results of the four-capacitor model are in good agreement with the experimental results, accurately reflecting the law and resonance characteristics of broadband transmission. However, the three-capacitor model has a large error compared with the experimental results. Although it successfully captured the resonance near 1.7kHz, the first resonance point is significantly different from the experimental result, and the high-frequency resonance point cannot be accurately simulated.

[0044] Example 4 is an embodiment of the present invention, illustrating a schematic scheme for a broadband characteristic analysis method for a capacitive voltage transformer. It should be noted that the technical solution of a broadband characteristic analysis system for a capacitive voltage transformer and the technical solution of the broadband characteristic analysis method for a capacitive voltage transformer described above belong to the same concept. Details not described in detail in the technical solution of the broadband characteristic analysis system for a capacitive voltage transformer in this embodiment can be found in the description of the technical solution of the broadband characteristic analysis method for a capacitive voltage transformer described above.

[0045] This embodiment provides a wideband characteristic analysis system for capacitive voltage transformers, including: a parameter acquisition module and a parameter optimization module; The parameter acquisition module acquires the basic parameters of the capacitive voltage transformer, as well as the stray parameters of the high-voltage arm capacitor and the inter-turn distributed capacitor; it calculates the parameters of the four-capacitor distributed model based on the basic parameters of the transformer primary and secondary sides, and calculates the parameters of the resistance-capacitance matching module based on the actual line simulation. The parameter optimization module combines all parameters to study wideband characteristics and assists in optimizing the parameters of the capacitive transformer. Based on the desired wideband characteristics, if the simulation results of the resonant point meet expectations, the transformer parameters are output.

[0046] This embodiment also provides an electronic device applicable to a method for analyzing the broadband characteristics of a capacitive voltage transformer, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the method for analyzing the broadband characteristics of a capacitive voltage transformer as proposed in the above embodiment.

[0047] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements a method for analyzing the wideband characteristics of a capacitive voltage transformer as proposed in the above embodiments.

[0048] The storage medium proposed in this embodiment belongs to the same inventive concept as the method for analyzing the wideband characteristics of a capacitive voltage transformer proposed in the above embodiments. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0049] Based on the above description of the implementation methods, those skilled in the art can clearly understand that the present invention can be implemented using software and necessary general-purpose hardware, and of course, it can also be implemented using hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk, or optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for analyzing the broadband characteristics of a capacitive voltage transformer, characterized in that: include, Obtain the basic parameters of the capacitive voltage transformer, and obtain the stray parameters of the high-voltage arm capacitance and the inter-turn distributed capacitance; The parameters of the four-capacitor distributed model are calculated using the basic parameters of the transformer primary and secondary sides, and the parameters of the resistance-capacitance matching module are calculated using the actual line simulation. By combining all parameters, a wideband characteristic study is conducted, and the parameters of the capacitive transformer are optimized. Based on the desired wideband characteristic, if the simulation results of the resonant point meet the expectations, the transformer parameters are output.

2. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 1, characterized in that: The basic parameters include those obtained through open / short circuit tests, frequency sweep tests, and those provided by the manufacturer for the capacitive voltage transformer. These parameters include the equivalent series resistance of the voltage divider capacitor, the equivalent series resistance and parallel capacitance of the compensating reactor, the inter-turn distributed capacitance of the primary and secondary windings of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, the equivalent copper loss resistance and equivalent leakage inductance of the secondary winding of the transformer, the equivalent distributed capacitance of the primary and secondary windings, the equivalent magnetizing resistance and magnetizing inductance of the transformer, the equivalent resistance and equivalent inductance of the damper referred to the primary winding, and the equivalent resistance and equivalent inductance of the load referred to the primary winding.

3. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 2, characterized in that: The stray parameters include high-frequency stray inductance and distributed capacitance; Using an impedance analyzer, the port impedance is scanned and measured over a wide frequency range. First resonant point and inductive reactance In the resistive region, the impedance increases linearly. By fitting the impedance of the current linear segment, the high-frequency stray inductance can be obtained. ; By short-circuiting the beginning and end of the high-voltage winding using the short-circuit-open-circuit method, the capacitance to ground at this short-circuit point is measured. Suspend the end of the high-voltage winding and measure the capacitance between the beginning and ground. Collect the distributed capacitance of the damper inductance. ≈ ² / .

4. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 3, characterized in that: The calculation of the parameters of the four-capacitor distributed model includes representing all components in impedance form according to the circuit model: in, and These are the equivalent series resistances of the voltage divider capacitors. and To compensate for the equivalent series resistance and equivalent parallel capacitance of the reactor, and These are the distributed capacitance between the turns on the primary side of the transformer and the distributed capacitance between the turns on the secondary side converted to the primary side, respectively. and These are the equivalent copper loss resistance and equivalent leakage inductance of the primary winding of the transformer, respectively. and These are the equivalent magnetizing resistance and magnetizing inductance of the transformer, respectively. and These are the equivalent resistance and equivalent inductance of the damper referred to the primary side, respectively. and These are the equivalent resistance and equivalent inductance of the load referred to the primary side, respectively. and These are voltage divider capacitors. and This is the equivalent series inductance of the voltage divider capacitor. To compensate for the equivalent series inductance of the reactor, The impedance is the distributed capacitance of the primary side. The impedance is the impedance of the transformer secondary-side inter-turn distributed capacitance referred to the primary side. The impedance is the equivalent distributed capacitance between the primary and secondary sides of the transformer. Let be the equivalent parallel capacitance of the damper referred to the primary side, and s be the complex frequency variable in the Laplace transform. and The impedance of the voltage divider capacitor branch is... To compensate for the impedance of the reactor, For the excitation branch impedance, This is the equivalent impedance of the transformer's leakage inductance and copper loss. The damper impedance, This is the load impedance.

5. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 4, characterized in that: The calculation of the four-capacitor distributed model parameters also includes transforming the delta connection formed by the transformer inter-turn distributed capacitance, transformer leakage inductance, and copper loss resistance into a star connection to obtain the voltage transfer function. : Where N is the transformer turns ratio, and K is the CVT rated turns ratio. Input voltage, For output voltage, , , , It is the equivalent impedance after star connection transformation.

6. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 5, characterized in that: The parameters of the resistance-capacitance matching module include those calculated based on the actual parameters of the secondary cable used in the actual field, such as cable type, nominal cross-section, and measured length, according to the unit length parameter.

7. The method for analyzing the broadband characteristics of a capacitive voltage transformer as described in claim 6, characterized in that: The parameter optimization includes, according to the transfer function formula If the number and location of the resonant points in the simulation results and the experimental curves of the four capacitors are the same, then the requirements are met. If it does not meet the requirements, the parameters are obtained again, and the parameters are adjusted or reduced based on empirical rules to optimize the parameters.

8. A wideband characteristic analysis system for a capacitive voltage transformer, employing the wideband characteristic analysis method for a capacitive voltage transformer as described in any one of claims 1 to 7, characterized in that, include: Parameter acquisition module, parameter optimization module; The parameter acquisition module acquires the basic parameters of the capacitive voltage transformer and the stray parameters of the high-voltage arm capacitor and the inter-turn distributed capacitor. The parameters of the four-capacitor distributed model are calculated using the basic parameters of the transformer primary and secondary sides, and the parameters of the resistance-capacitance matching module are calculated using the actual line simulation. The parameter optimization module combines all parameters to study wideband characteristics and assists in optimizing the parameters of the capacitive transformer. Based on the desired wideband characteristics, if the simulation results of the resonant point meet expectations, the transformer parameters are output.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method for analyzing the broadband characteristics of a capacitive voltage transformer according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the wideband characteristic analysis method for a capacitive voltage transformer according to any one of claims 1 to 7.

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