Transient oscillation law analysis method, system and equipment for direct current power flow controller and medium

Abstract

The invention relates to the technical field of electrical engineering, and discloses a DC power flow controller transient oscillation law analysis method, system, device and medium, and the method comprises the steps: obtaining the inertia characteristics of a sending end converter station, providing precise basic data for model building, and guaranteeing the accuracy and reliability of a model; a direct current power flow controller time domain model is established based on inertia characteristics, actual system dynamic behaviors can be truly reflected, and support is provided for frequency domain analysis; the establishment of the frequency domain model enables the transient characteristic analysis of the DC power flow controller to be more intuitive and convenient, and facilitates understanding and application; the transient characteristics can be accurately obtained by solving the frequency domain model, and a basis is provided for optimizing controller parameters and improving system stability. According to the method, the accuracy and efficiency of transient oscillation law analysis of the direct current power flow controller are improved, and guarantee is provided for stable operation and optimal control of a power system. The transient characteristics are deeply analyzed to facilitate understanding of the working principle and behavior characteristics, and scientific basis is provided for design and operation of a power system.

Description

Technical Field

[0001] This invention relates to the field of electrical engineering technology, and in particular to a method, system, device and medium for analyzing transient oscillation patterns in a DC power flow controller. Background Technology

[0002] As the proportion of new energy sources gradually increases, the uncertainties of distributed renewable energy make the operation of new power systems more difficult to predict and manage. The complex interaction network formed by multiple intertwined entities poses challenges to the stability and coordinated control of the system. Flexible DC transmission, with its advantages such as active / reactive power decoupling and the elimination of reactive power compensation, has broad application prospects in the field of new power systems. Relying on the flexible adjustment capabilities of flexible DC transmission, new power systems can improve system stability and coordination through the frequency support capabilities of flexible DC converter stations.

[0003] Flexible DC transmission technology based on voltage source converters offers an effective solution for large-scale, long-distance power transmission due to its large transmission capacity and flexible control. However, in a ring-structured DC grid, multiple transmission lines may exist between converter stations, making it impossible to effectively regulate power flow solely through converter station voltage and power control. This can lead to power flow loss control on some lines, causing overloads and threatening the safe operation of the system. DC power flow controllers can effectively enhance the power flow regulation capability of the mesh-type HVDC grid by adjusting line resistance and voltage. This paper proposes a transient oscillation analysis method for DC power flow controllers based on singular value decomposition (SVD) technology. This method can identify key influencing factors of switching oscillations in the power flow controller under frequency domain analysis.

[0004] The transient oscillation analysis of the DC power flow controller based on singular value decomposition (SVD) technology mainly includes four parts: construction of the DC power flow controller's time-domain model, construction of the DC power flow controller's frequency-domain model, SVD of the frequency-domain model, and transient law analysis of the DC power flow controller. In the transient and steady-state research of DC power flow controllers, most existing studies only focus on modular extensions of the DC power flow controller's topology or improvements in steady-state control performance. Few studies focus on the transient oscillation characteristics caused by switching of the DC power flow controller, and there is a lack of transient analysis studies that consider the simulation of the inertia characteristics of the sending-end converter station. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, this invention provides a method, system, device, and medium for analyzing the transient oscillation law of a DC power flow controller, which can solve the transient oscillation problem caused by the switching process of the DC power flow controller and improve the stability and security of the DC power grid.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a method for analyzing the transient oscillation law of a DC power flow controller, comprising:

[0009] The inertia characteristics of the sending-end converter station are obtained, and a time-domain model of the DC power flow controller containing the inertia characteristics is established based on the inertia characteristics of the sending-end converter station.

[0010] A frequency domain model of the DC power flow controller, incorporating inertia characteristics, is established based on the time domain model of the DC power flow controller.

[0011] The frequency domain model of the DC power flow controller with inertia characteristics is solved, and the transient characteristics of the DC power flow controller are obtained based on the solution results.

[0012] The transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

[0013] As a preferred embodiment of the transient oscillation law analysis method for the DC power flow controller described in this invention, the step of establishing a time-domain model of the DC power flow controller containing inertial characteristics based on the inertial characteristics of the sending-end converter station includes:

[0014] Integrate virtual inertia control power equations with droop characteristics at the sending-end converter station;

[0015] The virtual inertia control power equation is used to provide the required inertia and damping support for the target optical-storage-flexible system.

[0016] The virtual inertia control power equation is linearized.

[0017] As a preferred embodiment of the transient oscillation law analysis method for the DC power flow controller described in this invention, the step of establishing a time-domain model of the DC power flow controller containing inertial characteristics based on the inertial characteristics of the sending-end converter station further includes:

[0018] Obtain the original small-signal model of the DC power flow controller without inertia characteristics, and combine it with the linearization results to obtain the time-domain model of the DC power flow controller with inertia characteristics.

[0019] The time-domain model of the DC power flow controller with inertia characteristics is obtained by introducing two state variables obtained from the linearization process.

[0020] This preferred scheme improves the accuracy and applicability of the model, enabling the DC power flow controller to exhibit good transient characteristics under different operating conditions and parameters. Furthermore, by introducing the two state variables obtained through linearization, the dynamic behavior of the DC power flow controller can be reflected more accurately, providing a more reliable foundation for subsequent frequency domain analysis and transient characteristic solving.

[0021] As a preferred embodiment of the transient oscillation law analysis method for the DC power flow controller described in this invention, the step of establishing a time-domain model of the DC power flow controller containing inertial characteristics based on the inertial characteristics of the sending-end converter station further includes:

[0022] The time-domain model of the DC power flow controller is divided into a controllable system and an autonomous system.

[0023] The controllable system is the part of the DC power flow controller time-domain model that consists of state variables directly controlled by the PI controller.

[0024] The autonomous system is the part of the DC power flow controller time-domain model that consists of state variables indirectly controlled by a PI controller.

[0025] As a preferred embodiment of the transient oscillation law analysis method for DC power flow controllers described in this invention, the step of establishing a frequency domain model of the DC power flow controller containing inertia characteristics based on the time domain model of the DC power flow controller includes:

[0026] Establish the output variable expression for the autonomous system;

[0027] The output variable expression is obtained through several input state variables and the output transfer function matrix;

[0028] By integrating the output transfer function matrix of all state variables with respect to the output variable expressions, we obtain the autonomous system transfer function matrix;

[0029] The transfer function matrix of the autonomous system is used as the frequency domain model of the DC power flow controller with inertia characteristics.

[0030] As a preferred embodiment of the transient oscillation law analysis method for the DC power flow controller described in this invention, the step of solving the frequency domain model of the DC power flow controller containing inertia characteristics includes:

[0031] The frequency domain model of the DC power flow controller with inertia characteristics is solved by singular value decomposition.

[0032] The singular value decomposition results of the transfer function matrix of an autonomous system at all operating frequencies have maximum and minimum singular values.

[0033] The maximum singular value represents the maximum transient oscillation amplitude induced by the input disturbance energy;

[0034] The minimum singular value represents the lower limit of the minimum gain corresponding to the perturbation.

[0035] As a preferred embodiment of the transient oscillation law analysis method for the DC power flow controller described in this invention, the step of solving the frequency domain model of the DC power flow controller containing inertia characteristics further includes:

[0036] Performing frequency-sweep singular value analysis on the transfer function matrix of the autonomous system, the maximum singular value obtained can characterize the maximum response value of all key state variables of the autonomous system.

[0037] Secondly, the present invention provides a transient oscillation law analysis system for a DC power flow controller, comprising:

[0038] The time-domain model building module is used to obtain the inertia characteristics of the sending-end converter station and build a DC power flow controller time-domain model containing the inertia characteristics based on the inertia characteristics of the sending-end converter station.

[0039] The frequency domain conversion module is used to establish a frequency domain model of the DC power flow controller containing inertia characteristics based on the time domain model of the DC power flow controller.

[0040] The solution module is used to solve the frequency domain model of the DC power flow controller with inertia characteristics, and obtain the transient characteristics of the DC power flow controller based on the solution results.

[0041] The transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

[0042] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0043] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0044] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention proposes a method for analyzing the transient oscillation law of a DC power flow controller. First, by acquiring the inertia characteristics of the sending-end converter station, accurate basic data is provided for the subsequent model establishment, ensuring the accuracy and reliability of the model. Second, the time-domain model of the DC power flow controller established based on the inertia characteristics can more realistically reflect the dynamic behavior of the actual system, providing strong support for subsequent frequency-domain analysis. Third, the establishment of the frequency-domain model makes the transient characteristic analysis of the DC power flow controller more intuitive and convenient, facilitating understanding and application. Finally, by solving the frequency-domain model, the transient characteristics of the DC power flow controller can be accurately obtained, providing an important basis for optimizing controller parameters and improving system stability. The method of this invention not only improves the accuracy and efficiency of transient oscillation law analysis of DC power flow controllers, but also provides a strong guarantee for the stable operation and optimized control of power systems. By deeply analyzing the transient characteristics of DC power flow controllers, their working principles and behavioral characteristics can be better understood, providing a scientific basis for the design and operation of power systems. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the 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.

[0046] Figure 1 The present invention provides a flowchart of a method for analyzing the transient oscillation law of a DC power flow controller according to an embodiment of the present invention.

[0047] Figure 2 This is a block diagram of a power inertia control method with drooping characteristics, provided as an embodiment of the present invention for analyzing the transient oscillation law of a DC power flow controller.

[0048] Figure 3 The present invention provides a method for analyzing the transient oscillation law of a DC power flow controller, which includes the sending-end inertia characteristics of the DC power flow controller operating sub-mode 1.

[0049] Figure 4 The present invention provides a method for analyzing the transient oscillation law of a DC power flow controller, which includes the sending-end inertia characteristics of the DC power flow controller operating sub-mode 2.

[0050] Figure 5 This diagram illustrates the maximum singular value corresponding to the transfer function matrix of a transient oscillation law analysis method for a DC power flow controller, provided as an embodiment of the present invention.

[0051] Figure 6This diagram illustrates the maximum singular values ​​of the transfer function matrix corresponding to different line resistances in a transient oscillation law analysis method for a DC power flow controller, provided as an embodiment of the present invention.

[0052] Figure 7 This diagram illustrates the maximum singular value of the transfer function matrix corresponding to different line current reference values ​​in a transient oscillation law analysis method for a DC power flow controller, provided as an embodiment of the present invention.

[0053] Figure 8 This is a schematic diagram of a three-terminal medium-voltage DC transmission system with photovoltaic, energy storage, DC and flexible access, which provides a method for analyzing the transient oscillation law of DC power flow controllers according to an embodiment of the present invention.

[0054] Figure 9 An embodiment of the present invention provides a method for analyzing the transient oscillation law of a DC power flow controller under different line resistances. L Transient waveform diagram.

[0055] Figure 10 An embodiment of the present invention provides a method for analyzing the transient oscillation law of a DC power flow controller under different line resistances. C2 Transient waveform diagram.

[0056] Figure 11 This invention provides a method for analyzing the transient oscillation law of a DC power flow controller under different line current reference values, as an embodiment of the present invention. L Transient waveform diagram.

[0057] Figure 12 This invention provides a method for analyzing the transient oscillation law of a DC power flow controller under different line current reference values, as an embodiment of the present invention. C2 Transient waveform diagram.

[0058] Figure 13 This is an internal structure diagram of an electronic device for analyzing the transient oscillation law of a DC power flow controller, as provided in an embodiment of the present invention. Detailed Implementation

[0059] 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.

[0060] Example 1, referring to Figures 1-12 This is the first embodiment of the present invention, which provides a method for analyzing the transient oscillation law of a DC power flow controller, including:

[0061] Existing technologies have several limitations. For instance, the transient oscillation characteristics of DC power flow controllers are not studied in sufficient depth, and a systematic analytical method is lacking. Traditional analytical methods often focus only on the steady-state characteristics of DC power flow controllers, neglecting the oscillation phenomena during transient processes. This incomplete approach may lead to significant transient oscillations in DC power flow controllers during switching operations in practical applications, affecting system stability and safety.

[0062] This invention provides a method that can effectively solve the problems mentioned above. The following will describe in detail how to implement the transient oscillation law analysis method of the DC power flow controller with reference to several embodiments.

[0063] Figure 1 A flowchart of a method for analyzing the transient oscillation law of a DC power flow controller is shown, including:

[0064] S101, obtain the inertia characteristics of the sending-end converter station, and establish a time-domain model of the DC power flow controller containing inertia characteristics based on the inertia characteristics of the sending-end converter station.

[0065] It should be noted that current analyses of transient oscillations in DC power flow controllers often fail to adequately consider the inertia characteristics of the sending-end converter station. This oversight may lead to significant discrepancies between the analysis results and the actual system operation. The inertia characteristics of the sending-end converter station have a crucial impact on the dynamic response of the entire DC system, relating to the system's stability and recovery capability under disturbances.

[0066] Therefore, when conducting transient oscillation analysis of DC power flow controllers, the inertia characteristics of the sending-end converter station should be taken into consideration to more accurately predict and evaluate the system's transient behavior, thereby ensuring that the analysis results truly reflect the actual operating conditions of the DC system. In-depth research and analysis of the inertia characteristics of the sending-end converter station can optimize the control strategy of the DC power flow controller and improve the stability and reliability of the DC system, which is of great significance for ensuring the safe and stable operation of the power system.

[0067] In this embodiment of the invention, establishing a time-domain model of a DC power flow controller incorporating inertia characteristics based on the inertia characteristics of the sending-end converter station includes:

[0068] Integrate virtual inertia control power equations with droop characteristics at the sending-end converter station;

[0069] The virtual inertia control power equation is used to provide the required inertia and damping support for the target optical-storage-flexible system.

[0070] The virtual inertia control power equation is linearized.

[0071] It should be noted that a sending-end converter station refers to a conversion station in a power system, responsible for converting alternating current (AC) into direct current (DC) for long-distance transmission or connection to different types of power grids. In this invention, "sending end" refers to the input side of a DC transmission system.

[0072] It should be noted that inertia refers to a system's ability to resist frequency changes, typically provided by the rotating mass of a generator. For modern power systems containing a large amount of renewable energy, since these energy sources generally do not have the mechanical inertia of traditional synchronous generators, it may be necessary to simulate this inertia characteristic through other means to maintain system stability.

[0073] It should be noted that the virtual inertia control power equation is a method used to simulate the inertia characteristics of traditional synchronous generators, especially in inverter-based power systems such as photovoltaic and wind power. This equation allows the system to exhibit behavior similar to that of a traditional generator when faced with rapid changes (such as sudden increases or decreases in load), thus providing additional stability and control.

[0074] It should be noted that droop characteristic is a control strategy primarily used in grid-connected inverters, enabling them to automatically adjust voltage or frequency based on changes in output power, mimicking the behavior of traditional generator sets. This allows for power sharing among distributed energy resources and helps maintain the stable operation of the power grid.

[0075] In some specific implementations, the steps for integrating virtual inertia control power equations with droop characteristics at the sending-end converter station can be as follows:

[0076] First, the basic electrical parameters and control strategies of the sending-end converter station are determined. These parameters and strategies will serve as the basis for the design of the virtual inertia control power equations.

[0077] Next, based on the system's inertia requirements, a virtual inertia control algorithm with droop characteristics is designed. This algorithm should be able to adjust the output power in real time to respond to changes in the system frequency, thereby simulating inertia characteristics similar to those of a traditional synchronous generator.

[0078] Then, the designed virtual inertia control power equation is integrated into the control system of the sending-end converter station to ensure seamless integration with the existing control system.

[0079] Finally, simulation tests were conducted on the integrated sending-end converter station to verify the effectiveness of its inertia characteristics and the stability of its control performance.

[0080] In this embodiment of the invention, establishing a time-domain model of a DC power flow controller incorporating inertia characteristics based on the inertia characteristics of the sending-end converter station further includes:

[0081] Obtain the original small-signal model of the DC power flow controller without inertia characteristics, and combine it with the linearization results to obtain the time-domain model of the DC power flow controller with inertia characteristics.

[0082] The time-domain model of the DC power flow controller with inertia characteristics is obtained by introducing two state variables from the linearization process.

[0083] In this embodiment of the invention, establishing a time-domain model of a DC power flow controller incorporating inertia characteristics based on the inertia characteristics of the sending-end converter station further includes:

[0084] The time-domain model of the DC power flow controller is divided into a controllable system and an autonomous system.

[0085] The controllable system is the part of the DC power flow controller time-domain model that consists of state variables directly controlled by the PI controller;

[0086] The autonomous system is the part of the DC power flow controller time-domain model that consists of state variables indirectly controlled by the PI controller.

[0087] It should be noted that the small-signal model is a concept used in power electronics and control system analysis. It refers to a simplified model obtained by linearizing a nonlinear system near an operating point. This model is typically used to analyze the dynamic response of a system, especially in the face of small disturbances.

[0088] It should be noted that a controllable system refers to the part of the system consisting of state variables that can be directly controlled by a PI (proportional-integral) controller. This means that for this part of the system, its behavior can be directly affected by adjusting the parameters of the PI controller.

[0089] It's important to note that autonomous systems refer to the part of the system that, while also influenced by a PI controller, consists of state variables that are not directly controlled. In other words, the behavior of this part of the system is more determined by the internal dynamics of the system than by the direct control of an external controller.

[0090] Specifically, the sending-end converter station integrates a virtual inertia control power equation with droop characteristics to dynamically adjust the output power, thereby actively providing the necessary inertia and damping support for the photovoltaic-storage-DC-flexible system. Its corresponding control block diagram is shown below. Figure 2 As shown, the virtual inertia control power equation (per unit value) is expanded as follows:

[0091]

[0092] in, ΔP1 represents the per-unit value of variable x, and ΔP1 represents the drop in actual output power of the sending-end converter station VSC1 compared to the ideal output power under inertia characteristics. This represents the per-unit value of the drop. R1 represents the droop coefficient, J represents the inertia coefficient, D1 represents the damping coefficient, s is the Laplace coefficient, D indicates that the variable signal is a small signal, and u 11 This represents the voltage drop between the actual voltage at the VSC1 port of the sending-end converter station and the ideal voltage under inertia characteristics. The per-unit equation is transformed into a nominal equation as follows:

[0093]

[0094] Where K represents the per-unit value to nominal value conversion coefficient, u 1ref R represents the reference value for voltage control at the VSC1 port of the converter station. load This represents the local load of converter station VSC1. 12 with i 13 These represent the lines flowing through the DCPFC circuit. 12 and line 13 The current. To facilitate time-domain state-space modeling, ΔP1 is linearized as follows:

[0095]

[0096] Similarly, for VSC2 with virtual inertia control power characteristics, we have:

[0097]

[0098] Where ΔP2 represents the drop in actual output power of the sending-end converter station VSC2 compared to the ideal output power under inertia characteristics. R2 represents the droop coefficient, D2 represents the damping coefficient, and u 22 This represents the voltage drop between the actual voltage at the VSC2 port of the sending-end converter station and the ideal voltage under inertia characteristics. (These are per-unit values). The per-unit value equation is transformed into a named value equation as follows:

[0099]

[0100] Among them, u 2ref This indicates the reference value for voltage control at the VSC2 port of the converter station. 23 These represent the lines flowing through the DCPFC circuit. 23 The current. To facilitate time-domain state-space modeling, ΔP2 is linearized as follows:

[0101]

[0102] In some specific implementations, a time-domain state-space modeling method is used. To account for the virtual inertia power control of the sending-end VSC, two state variables (u) need to be introduced into the original small-signal model of the DC power flow controller without inertia characteristics.11 ,u 22 The model established is a twelfth-order small-signal model, which consists of the model and the corresponding differential equation (as shown below).

[0103]

[0104] The differential equations related to u1 and u2 are modified as follows:

[0105]

[0106]

[0107] u 1ref -u 11 =u C11 -(i 13 +i 12 )R load (13)

[0108]

[0109] u 2ref -u 22 =u C22 -(i 23 -i 12 )R load (15)

[0110] Among them, L 12 L 13 L 23 These represent DCPFC lines respectively. 12 ,line 13 and line 23 Inductance, i 12 i 13 i 23 These represent DCPFC lines respectively. 12 ,line 13 and line 23 Current. R 12 R 13 R 23 These represent DCPFC lines respectively. 12 ,line 13 ,line 23 Resistance, u C11 u C22 These represent the actual voltages at ports VSC1 and VSC2 of the sending-end converter station, respectively. C1 u C2 These represent the voltages across capacitors C1 and C2, respectively. s1 C s2These represent the capacitors at the VSC1 and VSC2 ports of the converter station, respectively. 1ref P 2ref These represent the power control reference values ​​for the sending-end converter station, respectively.

[0111] It should be noted that the time-domain state-space modeling method can comprehensively capture the dynamic behavior of the system, including the influence of inertia characteristics. This method clearly expresses the various components of the system and their interactions by establishing a precise mathematical model. Time-domain simulation analysis of this model provides a deeper understanding of the system's response characteristics under different operating conditions, thus offering strong support for optimizing control strategies. Furthermore, the time-domain state-space modeling method possesses high flexibility and scalability, capable of adapting to adjustments in system structure and the need for added functions, laying a solid foundation for further research and application of DC power flow controllers.

[0112] In some specific implementations, a complete switching cycle includes two operating sub-modes, including the sending end, such as... Figure 3 and Figure 4 As shown, the modular inductor-shared two-line DC power flow controller topology contains an energy buffer unit and two connection hub units (Part 1 and Part 2) connected in series with two DC lines. An energy exchange path is established between the energy buffer unit and the connection hub units via DC buses Bus a, Bus b, and Bus0. The internal topology of the connection unit Part i includes a capacitor C connected in series with DC line Line i. i Four IGBTs (Q Ai Q Bi Q Ci and Q Di ), four anti-parallel diodes (D Ai D Bi D Ci and D Di ) and four series-connected diodes D Asi D Bsi D Csi and D Dsi The bypass switch is a bidirectional switch, consisting of two IGBTs connected in reverse parallel. Based on the state variables related to the PI dual-loop control, the state variables of the DC power flow controller between the two lines can be divided: one part is fully controlled by the PI (forming a controllable system), and the other part is indirectly controlled (belonging to an autonomous system).

[0113] Specifically, the state variable i of the outer current loop of the dual-loop PI controller 13 The state variable u of the inner loop voltage loop C1Its output duty cycle d belongs to the controllable system, while the rest belong to the autonomous system. The state variable vectors of the controllable part and the autonomous part of the DC power flow controller, which takes into account the virtual inertia power control of the sending end VSC, are shown in Equation (16) and Equation (17), respectively.

[0114] ΔX1=[Δi 13 Δu C1 Δξ1 Δξ2] T (16)

[0115] ΔX2=[Δi L Δi 12 Δi 23 Δu C2 Δu C11 Δu C22 Δu 11 Δu 22 ] T (17)

[0116] Here, ΔX1 and ΔX2 represent the state variable vectors of the controllable system and the autonomous system, respectively. Their corresponding state-space equations are shown in equations (18) and (19), respectively:

[0117]

[0118] Among them, the controllable system-related variables include the system matrix A1, the input variable vector u1 (whose input matrix is ​​B1), and the cross-system input vector u 21 (From an autonomous system, its input matrix is ​​B) 21 ).

[0119] The relevant variables of the autonomous system include the system matrix A2, the input variable vector u2 (whose input matrix is ​​B2); and the input matrix B corresponding to u1. 12 The specific input variable vector of the controller is shown in equations (20)-(22):

[0120] Δu1=Δd (20)

[0121] Δu 21 =[Δi L Δi 12 Δi 23 Δu C2 Δu C11 Δu C22 Δu 11 Δu 22 ] T (twenty one)

[0122] Δu2=[Δi 13 Δu C1 Δξ1 Δξ2]T (twenty two)

[0123] In this embodiment of the invention, given that the three main input variables of the autonomous system are Δd, Δi, and Δi, 13 and Δu C1 These can be integrated into the input variable vector Δu3 of the autonomous system, as shown in equation (23):

[0124] Δu3=[Δd Δi 13 Δu C1 ] T (twenty three)

[0125] Therefore, the state-space equations of the autonomous system can be rewritten as shown in equations (24) and (25):

[0126]

[0127]

[0128] in, Let σ1, σ2, and σ3 represent the differentials of variable x. These can be further expanded as follows.

[0129]

[0130] σ3=u 1ref +R load (i 12 +i 13 (26)

[0131] It should be noted that obtaining the inertia characteristics of the sending-end converter station and establishing a time-domain model of the DC power flow controller incorporating these characteristics can more accurately simulate and analyze the dynamic behavior of the DC power flow controller in actual power systems. By introducing inertia characteristics, the model can more realistically reflect the response characteristics of the sending-end converter station when facing transient conditions such as load changes or faults, including the dynamic adjustment process of its voltage and current. This not only helps to deepen the understanding of the operating mechanism of the DC power flow controller but also provides a more accurate simulation environment for optimizing control strategies. Furthermore, this model can provide important references for the design and improvement of DC power flow controllers, promoting their widespread application in power systems.

[0132] S102, Establish a frequency domain model of a DC power flow controller with inertia characteristics based on the time domain model of the DC power flow controller;

[0133] It should be noted that while time-domain solutions can directly reflect the dynamic behavior of a system, they are computationally intensive and time-consuming when dealing with complex systems or performing multi-scenario analyses, and the frequency characteristics of the system are not easily observed directly. In contrast, frequency-domain models can reveal the behavioral characteristics of the system at different frequencies through frequency response analysis, providing a more intuitive perspective for the design and optimization of control strategies. By establishing a frequency-domain model of a DC power flow controller that includes inertia characteristics, it is easier to analyze the frequency response of the system under different operating conditions, evaluate the effectiveness of the control strategy, and thus provide more comprehensive theoretical guidance for the design and application of DC power flow controllers.

[0134] In some specific implementations, the steps for converting a time-domain model into a frequency-domain model may be as follows:

[0135] First, a Laplace transform is performed on the state-space equations in the time-domain model to convert the time-domain function into a frequency-domain function.

[0136] Next, using the matrix operation rules in linear algebra, the system transfer function in the frequency domain is derived. This transfer function describes the frequency relationship between the system input and output and is the core of the frequency domain model.

[0137] In addition, the manifestation of inertia characteristics in the frequency domain must be considered to ensure that the frequency domain model can accurately reflect the impact of the inertia characteristics of the sending-end converter station on the dynamic behavior of the system.

[0138] Finally, by verifying and calibrating the frequency domain model, we ensure that it can accurately simulate and analyze the frequency response characteristics of the DC power flow controller in a real power system.

[0139] In some specific implementations, the steps for converting the time-domain model into a frequency-domain model can also be achieved using the following steps:

[0140] First, the original time-domain model is discretized, transforming it into a discrete-time model. This step is to adapt to the processing capabilities of digital computers, making subsequent frequency-domain transformations more efficient and accurate.

[0141] Next, the discrete-time model is transformed into a Z-domain model using the Z-transform. The Z-transform is an important tool in discrete signal analysis, as it can convert discrete-time signals into functions on the complex plane, thus facilitating frequency domain analysis.

[0142] Then, the Z-domain model is transformed into a frequency-domain model through the mapping relationship from the Z-domain to the frequency domain. This step requires utilizing the properties of the Z-transform and relevant knowledge of frequency domain analysis to ensure that the transformed frequency-domain model can accurately reflect the dynamic behavior of the system.

[0143] In addition, special attention should be paid to the expression of inertia characteristics in the frequency domain during the processing to ensure that the converted frequency domain model can accurately capture the impact of the inertia characteristics of the sending-end converter station on the system frequency response.

[0144] Finally, the transformed frequency domain model is verified and calibrated to ensure that it can accurately simulate and analyze the transient oscillation law of DC power flow controller in actual power systems.

[0145] In this embodiment of the invention, establishing a frequency domain model of a DC power flow controller with inertia characteristics based on the time domain model of the DC power flow controller includes:

[0146] Establish the output variable expression for the autonomous system;

[0147] The output variable expression is obtained through several input state variables and the output transfer function matrix;

[0148] By integrating the output transfer function matrix of all state variables with respect to the output variable expressions, we obtain the autonomous system transfer function matrix;

[0149] The transfer function matrix of the autonomous system is used as the frequency domain model of the DC power flow controller with inertia characteristics.

[0150] It should be noted that the time-domain to frequency-domain transformation designed in this invention can more accurately capture the dynamic behavior of the DC power flow controller during transient processes, especially the influence of inertia characteristics on the system frequency response. Traditional transformation methods may ignore the precise expression of inertia characteristics in the frequency domain, leading to errors in the model when simulating and analyzing transient oscillations. The method in this embodiment of the invention, by meticulously processing the expression of inertia characteristics in the frequency domain, ensures the accuracy and reliability of the model. Furthermore, this method further improves the accuracy and applicability of the model by establishing the output variable expression and transfer function matrix of the autonomous system, enabling it to better adapt to the transient oscillation analysis needs under different power system conditions.

[0151] Specifically, assume that the i-th state variable in ΔX2 is the output variable ΔY of the autonomous system. 2_i (i = 1, 2, 3, ..., 8), then the output variable can be written in the form of equation (28):

[0152] ΔY 2_i =G i (s)Δu3,(i=1,2,3...,8) (27)

[0153] Among them, G i (s) represents the output transfer function matrix of the autonomous system. From equation (28), all inputs are u3, and the output is Y. 2_i The transfer function can be expressed in the form of equation (29):

[0154] G i (s)=C2(sI-A2) -1 B3, (i = 1, 2, 3..., 8) (28)

[0155] Where I is the identity matrix and s is the Laplace operator. Therefore, the transfer function matrix G(s) of the autonomous system can be written as shown in equation (30):

[0156]

[0157] After expanding Δu3, the transfer function matrix G(s) of the autonomous system can be re-expressed as shown in equation (31):

[0158]

[0159] It should be noted that considering only the autonomous system simplifies the analysis process, allowing for a more intuitive understanding of the system's internal dynamic behavior. By ignoring external disturbances and inputs, this invention can focus on the system's inherent characteristics, such as oscillation frequency and damping ratio. These parameters are crucial for evaluating the system's stability and performance. Furthermore, the analysis of the autonomous system helps in designing a more effective controller to handle various transient oscillations, thereby improving the overall performance and reliability of the DC power flow controller.

[0160] It should also be noted that establishing a frequency domain model of the DC power flow controller, incorporating inertia characteristics, based on the time domain model of the DC power flow controller allows for a deeper understanding of the controller's dynamic response characteristics in the frequency domain. The frequency domain model provides an intuitive representation of the system's oscillation modes, aiding in the identification and analysis of key frequency components. Frequency domain analysis allows for a more accurate evaluation of the controller's gain and phase response at different frequencies, which is crucial for designing and optimizing control strategies. Furthermore, the frequency domain model simplifies the system stability analysis process, providing strong support for designing more robust controllers.

[0161] S103, Solve the frequency domain model of the DC power flow controller with inertia characteristics, and obtain the transient characteristics of the DC power flow controller based on the solution results;

[0162] It is important to note that solving the frequency domain model after obtaining it is a crucial step in analyzing the transient characteristics of a DC power flow controller. Solving the frequency domain model typically involves frequency response analysis of the transfer function, which can be achieved using various mathematical tools and methods, such as Bode plots and Nyquist plots. These tools can visually display the system's gain and phase response at different frequencies, thus helping us understand the system's dynamic behavior.

[0163] It is also important to note that during the solution process, special attention must be paid to the impact of inertia characteristics on the system's frequency response. Since inertia characteristics reflect the response speed and capability of the sending-end converter station in the face of transient conditions such as load changes or faults, they have a significant impact on the system's stability and performance. In the frequency domain model, inertia characteristics are typically represented by certain parameters or terms in the transfer function, and changes in these parameters or terms directly affect the system's frequency response characteristics.

[0164] In some practical applications, the frequency domain model of a DC power flow controller with inertia characteristics can be solved using numerical methods, such as frequency response analysis using simulation software like MATLAB / Simulink. Alternatively, analytical methods can be employed, such as pole-zero analysis based on the transfer function, to solve for the system's frequency response characteristics. Pole-zero analysis can reveal the system's oscillation modes and stability; by determining the locations of the poles and zeros of the transfer function, the system's stability and response speed at different frequencies can be evaluated. This method is crucial for understanding and optimizing the transient characteristics of DC power flow controllers, especially when designing controllers to handle specific transient conditions.

[0165] In some specific practical applications, when using pole-zero analysis of the transfer function, the specific steps can be as follows:

[0166] First, a transfer function model of the DC power flow controller needs to be established, typically based on the system's physical characteristics and control strategy. The transfer function usually includes parameters reflecting inertia characteristics.

[0167] Next, using mathematical tools or software, such as MATLAB, pole-zero analysis is performed on the transfer function. The aim is to identify the locations of the poles and zeros of the transfer function, which correspond to the oscillation modes and stability boundaries of the system, respectively.

[0168] Then, based on the locations of the poles and zeros, the stability and response speed of the system at different frequencies can be analyzed. For example, the real part of the poles determines the decay rate of the system, while the imaginary part is related to the oscillation frequency. The location of the zeros also affects the frequency response characteristics of the system.

[0169] Furthermore, the relationship between poles and zeros can be further analyzed, such as their distance and relative position, to gain a deeper understanding of the system's dynamic behavior.

[0170] Finally, based on the results of pole-zero analysis, the controller parameters can be adjusted or its structure optimized to improve its transient performance and stability. This process may require multiple iterations and analyses until satisfactory control results are achieved.

[0171] In this embodiment of the invention, the singular value decomposition method is used to solve the frequency domain model of the DC power flow controller with inertia characteristics.

[0172] In this embodiment of the invention, transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

[0173] In this embodiment of the invention, solving the frequency domain model of the DC power flow controller with inertia characteristics includes:

[0174] The frequency domain model of the DC power flow controller with inertia characteristics is solved by singular value decomposition.

[0175] The singular value decomposition results of the transfer function matrix of an autonomous system at all operating frequencies have maximum and minimum singular values.

[0176] The maximum singular value represents the maximum transient oscillation amplitude induced by the input disturbance energy;

[0177] The minimum singular value represents the lower limit of the minimum gain corresponding to the perturbation.

[0178] In this embodiment of the invention, solving the frequency domain model of the DC power flow controller with inertia characteristics further includes:

[0179] Performing frequency-sweep singular value analysis on the transfer function matrix of the autonomous system, the maximum singular value obtained can characterize the maximum response value of all key state variables of the autonomous system.

[0180] It should be noted that Singular Value Decomposition (SVD) is a matrix factorization technique widely used in signal processing, control systems, and other fields. For a given matrix, SVD decomposes it into the product of three matrices, where the middle matrix is ​​a diagonal matrix containing the singular values ​​of the original matrix. In control systems, SVD can help identify key dynamic characteristics of the system, such as system stability and response speed.

[0181] In this embodiment of the invention, the singular value decomposition result of the autonomous system transfer function matrix at all operating frequencies has a maximum singular value and a minimum singular value:

[0182] The maximum singular value characterizes the maximum transient oscillation amplitude induced by the input disturbance. When the system is subjected to external disturbances, the maximum possible oscillation amplitude can be predicted based on the maximum singular value.

[0183] The minimum singular value characterizes the lower bound of the minimum gain response to a disturbance. It refers to the minimum degree of system response to an input disturbance, that is, the minimum extent to which the system can suppress external disturbances.

[0184] It's important to note that performing swept-frequency singular value analysis (SVA) on the transfer function matrix of an autonomous system involves calculating the singular values ​​of the transfer function matrix at different frequency points to analyze the system's behavior across the entire frequency range. This method allows us to obtain the system's dynamic performance indicators at various frequencies. The largest singular value found during swept-frequency SVA can be used to represent the maximum response value of all key state variables (those that best reflect the system's dynamic characteristics) to an input disturbance. This helps in understanding the system's stability and response characteristics at different frequencies.

[0185] In this embodiment of the invention, transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters. Specifically, "transient characteristics" refers to the short-term behavior of the system after experiencing sudden changes (such as faults, load mutations, etc.). By analyzing the DC power flow controller under different operating conditions (such as different load conditions, different power grid structures, etc.) and parameter settings, it is possible to assess how these factors affect the transient oscillation behavior of the system.

[0186] For example, when performing the singular value decomposition operation used in this invention to solve the frequency domain model, let G(s) be an 8×3 matrix with a rank of 3. The singular value decomposition form of the non-singular matrix G(s) is shown in equation (32):

[0187] G(s) = UDV T

[0188]

[0189] Where U is an 8th-order orthogonal matrix, whose columns are G(s)G T The eigenvectors of (s) are composed of V; V is a 3rd order orthogonal matrix whose columns are composed of G. T The eigenvectors of G(s) are composed of σ1, σ2, and σ3, which are singular values ​​of G(s) and are also eigenvalues ​​of G(s). T (s) are the non-zero eigenvalues ​​of G(s); O is the zero matrix. Equation (32) is the singular value decomposition of G(s), which can be written in the form of equation (33):

[0190]

[0191] Among them, u i (i = 1, 2, 3, ..., 8) are eigenvectors from the orthogonal matrix U, v j (j=1,2,3) are eigenvectors from the orthogonal matrix V. In frequency domain analysis, the singular value decomposition result of the transfer function matrix G(jω) at the full operating frequency has a maximum value σ. max (ω) and minimum value σ min (ω). σ max(ω) represents the maximum transient oscillation amplitude that the input disturbance may induce, σ min (ω) represents the lower bound of the minimum gain response to the disturbance, reflecting the system's robustness. A swept-frequency singular value analysis is performed on the transfer function matrix G(s) to obtain the maximum singular value σ. max (ω) can characterize the maximum response of all key state variables of the autonomous system that can be excited by Δu3, as shown in the results. Figure 5 As shown.

[0192] It should be noted that line parameters and line current control commands are key factors affecting the transient oscillation characteristics of DCPFC with inertia characteristics.

[0193] Figure 6 The simulation results show that as the line resistance increases, the maximum singular value of the system decreases significantly; while Figure 7 Further analysis reveals that reducing the line current reference command can simultaneously reduce the peak value of the system's maximum singularity. Comprehensive analysis shows that increasing the line resistance or decreasing the current reference command can effectively suppress DCPFC transient oscillations.

[0194] In summary, this invention proposes a method for analyzing the transient oscillation law of a DC power flow controller. First, by acquiring the inertia characteristics of the sending-end converter station, accurate foundational data is provided for subsequent model establishment, ensuring the model's accuracy and reliability. Second, the time-domain model of the DC power flow controller established based on the inertia characteristics can more realistically reflect the dynamic behavior of the actual system, providing strong support for subsequent frequency-domain analysis. Third, the establishment of the frequency-domain model makes the transient characteristic analysis of the DC power flow controller more intuitive and convenient, facilitating understanding and application. Finally, by solving the frequency-domain model, the transient characteristics of the DC power flow controller can be accurately obtained, providing an important basis for optimizing controller parameters and improving system stability. This invention not only improves the accuracy and efficiency of transient oscillation law analysis of DC power flow controllers but also provides strong guarantees for the stable operation and optimized control of power systems. In-depth analysis of the transient characteristics of the DC power flow controller allows for a better understanding of its working principle and behavioral characteristics, providing a scientific basis for the design and operation of power systems.

[0195] Example 2, in a preferred embodiment, in such a way Figure 8 The transient oscillation law analysis method of the sender-end inertia control DC power flow controller based on singular value decomposition technology is verified in the three-terminal medium-voltage DC transmission system with photovoltaic-storage-DC-flexible integration shown. A shared inductance-type two-line DC power flow controller is placed on the line of the three-terminal medium-voltage DC transmission system. 13 and line 23In this study, by changing the reference commands for line resistance and line current, the effectiveness of the DCPFC transient oscillation law analysis method, which takes into account inertia characteristics, in characterizing the actual oscillation condition was verified. The system parameters are shown in Table 1.

[0196] Table 1: Parameters of a Three-Terminal Medium-Voltage DC Transmission System with Photovoltaic-Storage-DC-Flexible Integration

[0197]

[0198] Table 2: Experimental parameters for the contribution of different line resistances to oscillation.

[0199]

[0200] Table 3: Experimental parameters for the contribution of different line current reference values ​​to oscillation.

[0201]

[0202] Set the line current reference command to 3.5A, and gradually increase the total line resistance. The line resistance parameters are shown in Table 2. After 1 second, connect the DC power flow controller to the medium-voltage DC transmission system. From Figure 9 and Figure 10 It can be seen that the main state variable i in the transient order reduction model L with u C2 The transient oscillation decreases as the line resistance increases. Set the line resistance R... line The line current reference command is gradually increased from 1.0Ω, as shown in Table 3. After 1 second, the DCPFC is connected to the medium-voltage DC transmission system. From... Figure 11 and Figure 12 It can be seen that the larger the reference value of the line current, the larger the main state variable i in the transient reduced-order model. L with u C2 The transient oscillation increases with the increase of the line current reference command. In summary, the DCPFC transient oscillation method, which takes into account the inertia characteristics, can effectively characterize the actual oscillation condition.

[0203] Example 3, referring to Figure 13 This embodiment also provides a transient oscillation law analysis system for DC power flow controllers, including:

[0204] The time-domain model building module is used to obtain the inertia characteristics of the sending-end converter station and build a time-domain model of the DC power flow controller containing inertia characteristics based on the inertia characteristics of the sending-end converter station.

[0205] The frequency domain conversion module is used to establish a frequency domain model of a DC power flow controller with inertia characteristics based on the time domain model of the DC power flow controller;

[0206] The solver module is used to solve the frequency domain model of the DC power flow controller with inertia characteristics, and obtain the transient characteristics of the DC power flow controller based on the solution results.

[0207] Transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

[0208] The above-mentioned unit modules can be embedded in the processor of the electronic device in hardware form or independent of it, or they can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of the above modules.

[0209] This embodiment also provides an electronic device, which can be a terminal, and its internal structure diagram can be as follows: Figure 13 As shown, the electronic device includes a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for analyzing the transient oscillation law of a DC power flow controller. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the device's casing, or an external keyboard, touchpad, or mouse.

[0210] This embodiment also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, it performs the following steps:

[0211] Obtain the inertia characteristics of the sending-end converter station, and establish a time-domain model of the DC power flow controller containing inertia characteristics based on the inertia characteristics of the sending-end converter station.

[0212] A frequency domain model of a DC power flow controller with inertia characteristics is established based on the time domain model of the DC power flow controller.

[0213] The frequency domain model of the DC power flow controller with inertia characteristics is solved, and the transient characteristics of the DC power flow controller are obtained based on the solution results.

[0214] Transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

[0215] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended 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.

[0216] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0217] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for analyzing the transient oscillation law of a DC power flow controller, characterized in that, include: The inertia characteristics of the sending-end converter station are obtained, and a time-domain model of the DC power flow controller containing the inertia characteristics is established based on the inertia characteristics of the sending-end converter station. A frequency domain model of the DC power flow controller, incorporating inertia characteristics, is established based on the time domain model of the DC power flow controller. The frequency domain model of the DC power flow controller with inertia characteristics is solved, and the transient characteristics of the DC power flow controller are obtained based on the solution results. The transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

2. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 1, characterized in that, The establishment of a time-domain model for a DC power flow controller incorporating inertial characteristics based on the inertial characteristics of the sending-end converter station includes: Integrate virtual inertia control power equations with droop characteristics at the sending-end converter station; The virtual inertia control power equation is used to provide the required inertia and damping support for the target optical-storage-flexible system. The virtual inertia control power equation is linearized.

3. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 2, characterized in that, The establishment of a DC power flow controller time-domain model incorporating inertia characteristics based on the inertia characteristics of the sending-end converter station also includes: Obtain the original small-signal model of the DC power flow controller without inertia characteristics, and combine it with the linearization results to obtain the time-domain model of the DC power flow controller with inertia characteristics. The time-domain model of the DC power flow controller with inertia characteristics is obtained by introducing two state variables obtained from the linearization process.

4. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 3, characterized in that, The establishment of a DC power flow controller time-domain model incorporating inertia characteristics based on the inertia characteristics of the sending-end converter station also includes: The time-domain model of the DC power flow controller is divided into a controllable system and an autonomous system. The controllable system is the part of the DC power flow controller time-domain model that consists of state variables directly controlled by the PI controller. The autonomous system is the part of the DC power flow controller time-domain model that consists of state variables indirectly controlled by a PI controller.

5. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 4, characterized in that, The establishment of the frequency domain model of the DC power flow controller with inertia characteristics based on the time domain model of the DC power flow controller includes: Establish the output variable expression for the autonomous system; The output variable expression is obtained through several input state variables and the output transfer function matrix; By integrating the output transfer function matrix of all state variables with respect to the output variable expressions, we obtain the autonomous system transfer function matrix; The transfer function matrix of the autonomous system is used as the frequency domain model of the DC power flow controller with inertia characteristics.

6. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 5, characterized in that, Solving the frequency domain model of the DC power flow controller with inertia characteristics includes: The frequency domain model of the DC power flow controller with inertia characteristics is solved by singular value decomposition. The singular value decomposition results of the transfer function matrix of an autonomous system at all operating frequencies have maximum and minimum singular values. The maximum singular value represents the maximum transient oscillation amplitude induced by the input disturbance energy; The minimum singular value represents the lower limit of the minimum gain corresponding to the perturbation.

7. The method for analyzing the transient oscillation law of a DC power flow controller as described in claim 6, characterized in that, The solution to the frequency domain model of the DC power flow controller with inertia characteristics also includes: Performing frequency-sweep singular value analysis on the transfer function matrix of the autonomous system, the maximum singular value obtained can characterize the maximum response value of all key state variables of the autonomous system.

8. A transient oscillation law analysis system for a DC power flow controller, using the method described in any one of claims 1 to 7, characterized in that, include: The time-domain model building module is used to obtain the inertia characteristics of the sending-end converter station and build a DC power flow controller time-domain model containing the inertia characteristics based on the inertia characteristics of the sending-end converter station. The frequency domain conversion module is used to establish a frequency domain model of the DC power flow controller containing inertia characteristics based on the time domain model of the DC power flow controller. The solution module is used to solve the frequency domain model of the DC power flow controller with inertia characteristics, and obtain the transient characteristics of the DC power flow controller based on the solution results. The transient characteristics include the influence of DC power flow controller parameters on transient oscillations under different system operating conditions and parameters.

9. An electronic 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 transient oscillation law analysis method for a DC power flow controller 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 transient oscillation law analysis method for a DC power flow controller according to any one of claims 1 to 7.

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