Power system transient simulation method and device based on virtual admittance

Abstract

The invention provides an electric power system transient simulation method based on virtual admittance. The method comprises the following steps: acquiring node voltage and phase angle value of each dynamic element in a to-be-simulated electric power system at the current moment; calculating node injection current of each dynamic element based on the node voltage and the phase angle value of each dynamic element, and calculating a virtual admittance matrix of each dynamic element according to the node voltage and the node injection current of each dynamic element; correcting the network equation of the current time step by using the virtual admittance matrix to obtain a new network equation; and performing transient simulation of the power system at the current time step by using the new network equation until a simulation convergence condition is met. According to the simulation method provided by the invention, the network equation of the system is corrected by using the virtual admittance matrix, so that the convergence of transient simulation is improved, especially for a new energy grid-connected system, equivalent transformation of a whole-system simulation model taking convergence improvement as a target can be realized, and the problem of non-convergence of simulation is solved.

Description

Technical Field

[0001] The present invention belongs to the field of power system simulation technology, and in particular to a method and device for power system transient simulation based on virtual admittance. Background Art

[0002] With the development of new power systems, more and more new energy sources such as wind power and photovoltaics are connected to the grid. As the proportion of new energy in the system increases, the system is increasingly showing characteristics such as strong randomness in operation mode, low system inertia, and weak voltage support strength, due to the natural properties of new energy units such as randomness, volatility, and weak support. This leads to a decrease in the system's anti-disturbance ability and a wide range of fault impact. Therefore, it is particularly important to analyze the operation status of the power system through time domain simulation.

[0003] In traditional simulation algorithms, the mathematical models of various dynamic components can be explicitly expressed through differential algebraic equations. Therefore, the convergence of the simulation can be improved by equivalent transformation of the mathematical model equations of the components. However, for new energy equipment such as wind power and photovoltaic power generation, since their control strategies and structural designs are the manufacturer's commercial secrets, power grid companies cannot directly obtain the explicit mathematical models of new energy equipment. What they can obtain is the packaged model of the new energy equipment, which is generally a compiled and encrypted DLL model. As the scale of the power system continues to expand, the rigidity of the whole system model continues to increase. Since the packaged model provided by the manufacturer cannot transform the system model through explicit changes, the convergence of the system time domain simulation is becoming more and more common.

[0004] Therefore, in the context of large-scale renewable energy grid connection, how to solve the algorithm convergence problem of integrating a large number of packaged models in the system during time domain simulation is an issue worthy of in-depth study. Summary of the invention

[0005] Based on this, the present invention aims to propose a method and device for transient simulation of power systems based on virtual admittance. For systems containing new energy, the virtual admittance of the package model of each dynamic element is calculated to correct the network equations of the system, thereby improving the convergence of time domain simulation.

[0006] In a first aspect, the present invention provides a method for transient simulation of a power system based on virtual admittance, comprising:

[0007] Obtaining node voltage and phase angle values ​​of each dynamic element in the power system to be simulated at the current moment;

[0008] Calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element;

[0009] Use the virtual admittance matrix to correct the network equation of the current time step and obtain a new network equation;

[0010] The new network equations are used to perform transient simulation of the power system at the current time step until the simulation convergence conditions are met.

[0011] Further, calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element includes:

[0012] The node voltage is vector-decomposed using the phase angle value to obtain the voltage component;

[0013] The disturbance value is set for the voltage component, and the voltage component and the disturbance value are input into the dynamic model of the dynamic element for calculation, so as to obtain the node injection current component corresponding to each voltage component.

[0014] Furthermore, the voltage components obtained by vector decomposing the node voltage using the phase angle value include:

[0015] The node voltage is vector-decomposed on the x-axis and y-axis using the phase angle value. The specific decomposition is as follows:

[0016]

[0017] in, and Represents the node voltage The x-axis and y-axis components of Indicates the phase angle value.

[0018] Furthermore, the disturbance amount is set for each voltage component, and the voltage component and the disturbance amount are input into the dynamic model of the dynamic element for calculation, and the node injection current components corresponding to each voltage component are obtained, including:

[0019] Based on the linear sensitivity method, the voltage component and Set the disturbance amount separately and ;

[0020] The voltage component and Input the dynamic model of the dynamic element to obtain the injected current and ;

[0021] Apply a disturbance in the x-axis direction of the node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the first node injection current component ;

[0022] Apply a disturbance in the y-axis direction of the node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the second node injection current component .

[0023] Further, calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element includes:

[0024] The following system of equations is constructed using the voltage components and node injection current components:

[0025]

[0026]

[0027] Solve the equations to get the virtual admittance matrix of each dynamic element .

[0028] Furthermore, the network equations for correcting the current time step using the virtual admittance matrix include:

[0029] The virtual admittance matrices of all dynamic elements in the power system are formed into diagonal block matrices;

[0030] The initial network equation is transformed using the diagonal block matrix according to the following relationship: Correction:

[0031]

[0032] Solve the above equation for , we get the new network equation, where represents the network admittance matrix of the power system, represents the node voltage vector, represents the node injection current vector, Represents the diagonal block matrix composed of the virtual admittance matrices of all dynamic elements, which has the following expression:

[0033]

[0034] Where n represents the number of dynamic elements in the power system, Represents the virtual admittance matrix of the nth dynamic element.

[0035] Furthermore, in the transient simulation of the power system, the simulation convergence conditions for each time step include:

[0036]

[0037] Where k represents the number of iterations per time step, and They represent the node voltages at the kth and k-1th iterations in the same time step, Represents the convergence threshold.

[0038] In a second aspect, the present invention provides a power system transient simulation device based on virtual admittance, comprising:

[0039] A data acquisition module is used to obtain the node voltage and phase angle value of each dynamic element in the power system to be simulated at the current moment;

[0040] The virtual admittance calculation module is used to perform the virtual admittance matrix calculation process in the first iteration calculation of the current time step. The virtual admittance matrix calculation process includes:

[0041] Calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element;

[0042] A network equation correction module is used to correct the network equation of the current time step using a virtual admittance matrix;

[0043] The transient simulation module is used to perform transient simulation of the power system at the current time step using the network equations until the simulation convergence conditions are met.

[0044] In a third aspect, the present invention provides an electronic device comprising a memory storing computer executable instructions and a processor, wherein when the computer executable instructions are executed by the processor, the device executes the various steps of the virtual admittance-based power system transient simulation method provided in the first aspect.

[0045] In a fourth aspect, the present invention provides a readable storage medium storing a computer executable program, which, when executed, can implement the various steps of the method for transient simulation of a power system based on virtual admittance provided in the first aspect.

[0046] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0047] The present invention provides a method for transient simulation of an electric power system based on virtual admittance. The corresponding virtual admittance matrix is ​​calculated according to the node voltage and phase angle value of each dynamic element at the current moment, and the network equation of the system is corrected by using the virtual admittance matrix, so as to improve the convergence of the transient simulation. The virtual admittance matrix is ​​used to simulate the real response of the dynamic element, so that the system model can be equivalently transformed even in the absence of an explicit mathematical model of the element. Especially for a system connected to a new energy grid, the equivalent transformation of the whole system simulation model with the goal of improving convergence can be realized, so as to solve the problem of non-convergence of the simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 A flowchart of an implementation method of a power system transient simulation method based on virtual admittance provided by an embodiment of the present invention;

[0050] Figure 2 A flowchart of an implementation method of a power system transient simulation method based on virtual admittance provided by another embodiment of the present invention;

[0051] Figure 3 An electrical structure diagram of an improved IEEE-9 node system provided by an embodiment of the present invention, wherein a wind farm and a photovoltaic power station are connected to nodes 5 and 6 respectively;

[0052] Figure 4 for Figure 3 Schematic diagram of wind farm node voltage test results in IEEE-9 node system;

[0053] Figure 5 for Figure 3 Schematic diagram of the voltage test results of photovoltaic power station nodes in the IEEE-9 node system;

[0054] Figure 6 for Figure 3 Schematic diagram of the node voltage test result of the synchronous generator connected to node 1 in the IEEE-9 node system;

[0055] Figure 7 for Figure 3 Schematic diagram of the iteration results of the node voltage at the wind farm grid connection point in the IEEE-9 node system in the first time step after the system fault;

[0056] Figure 8 for Figure 3 Schematic diagram of the iterative results of the node voltage at the first time step after the system failure in the IEEE-9 node system.

[0057] Fig. 9 A schematic diagram of the structure of a power system transient simulation device based on virtual admittance provided by an embodiment of the present invention;

[0058] Fig.10 This is a diagram of the electronic device architecture provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Transient simulation of power systems is a simulation of the dynamic response of power systems after disturbances (such as faults, load fluctuations, or equipment switching). It tracks the changes in the power system state over time by solving the system's differential algebraic equations. Simulations with good convergence can ensure that the equations are quickly and accurately solved during the iteration of each time step. If the simulation does not converge, the system state may not be updated correctly, causing the simulation results to deviate from the actual situation and affecting decision-making.

[0061] However, the connection of renewable energy to the grid has a significant impact on the convergence of transient simulation of power systems, especially when a high proportion of renewable energy is connected to the grid. New energy equipment usually cannot be directly converted into explicit mathematical models, and its nonlinear characteristics and complex control strategies also aggravate the problem of difficulty in simulation convergence.

[0062] Based on this, an embodiment of the present invention proposes a method for transient simulation of power systems based on virtual admittance. For systems containing new energy, the virtual admittance of the package model of each dynamic element is calculated to correct the network equation of the system, thereby improving the convergence of time domain simulation.

[0063] See also Figure 1 An embodiment of the present invention provides a method for transient simulation of a power system based on virtual admittance, comprising the following steps:

[0064] Step S110: Obtain node voltages and phase angle values ​​of each dynamic element in the power system to be simulated at the current moment.

[0065] Specifically, the node voltage and phase angle values ​​of dynamic elements can be obtained by solving the system's power flow equation (i.e., the initial network equation of the power grid). Dynamic elements refer to devices with dynamic behavior that require differential equations or other time-dependent models to describe their transient response and long-term dynamic behavior. The states of these elements change over time and are usually used to analyze the response of the system under disturbances, faults or other dynamic conditions, including generators, loads, inverters, etc.

[0066] The power system is modeled by the node admittance matrix, which represents the electrical relationship between nodes. The initial network equation of the system can be expressed as ,in represents the node admittance matrix of the power system, represents the node voltage vector, Represents the node injection current vector.

[0067] Step S120. Calculate the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculate the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element.

[0068] During the simulation process, the value of the virtual admittance matrix is ​​dynamically adjusted according to the real-time status of the dynamic elements (such as node voltage and current) at each time step. Therefore, the virtual admittance matrix of each dynamic element is calculated at the first iteration of each simulation time step, and the subsequent iterations of the same time step are no longer calculated until the first iteration of the next time step. The virtual admittance matrix is ​​obtained by actively introducing virtual disturbances in the system to obtain the dynamic response and control characteristics of the system, and does not represent the admittance of the real physical line.

[0069] The node injection current of a dynamic element is determined by the relationship between the element's voltage and its impedance or admittance. Therefore, the dynamic model of each element is used to solve the injection current based on its node voltage and phase angle value and the power injected by the element. The virtual admittance matrix reflects the response of each dynamic element to voltage changes. Once the node voltage and injection current are known when a virtual disturbance is introduced, the corresponding virtual admittance can be obtained according to Ohm's law. The virtual admittance of each dynamic element is organized into a diagonal matrix, which is the virtual admittance matrix of the system.

[0070] In a further embodiment, when calculating the node injection current of the dynamic element, the node voltage is vector decomposed using the phase angle value to obtain voltage components, a disturbance value is set for the voltage component, the voltage component and the disturbance value are input into the dynamic model of the dynamic element for calculation, and the node injection current components corresponding to each voltage component are obtained.

[0071] Step S130: Use the virtual admittance matrix to correct the network equation of the current time step to obtain a new network equation.

[0072] Specifically, the accuracy and convergence of transient simulation can be improved by introducing the nonlinear characteristics and control behaviors of dynamic elements into the network equations. The virtual admittance matrix is ​​used to dynamically update the node admittance matrix of the power system, so that the system model can accurately reflect the instantaneous state changes of dynamic elements in the simulation of each time step.

[0073] In a further embodiment, step S130 includes the following steps:

[0074] The virtual admittance matrices of all dynamic elements in the power system are formed into diagonal block matrices;

[0075] The initial network equation is transformed using the diagonal block matrix according to the following relationship: Correction:

[0076]

[0077] Solve the above equation for , we get the new network equation, where represents the node admittance matrix of the power system, represents the node voltage vector, represents the node injection current vector, Represents the diagonal block matrix composed of the virtual admittance matrices of all dynamic elements, which has the following expression:

[0078]

[0079] Where n represents the number of dynamic elements in the power system, Represents the virtual admittance matrix of the nth dynamic element. For nodes in the system that have no dynamic elements connected, their virtual admittance is set to a zero matrix.

[0080] Step S140: Use the new network equations to perform transient simulation of the power system at the current time step until the simulation convergence conditions are met.

[0081] Specifically, in each iterative calculation, according to the control strategy of the dynamic components (such as the excitation system of the generator, the control model of the inverter, etc.), the injection current of each dynamic component at the current moment is calculated, and the node voltage and phase angle value are solved by the iterative solution method according to the modified network equation, and the convergence of the network equation is checked at the same time. The convergence condition is usually that the change in node voltage is less than the set threshold. If it is met, the simulation of the current time step has converged, and the system state is updated to enter the next time step, and the simulation is repeated until the maximum simulation time is reached or the set termination condition is reached.

[0082] The power system transient simulation method based on virtual admittance provided by the present invention is further introduced below through another embodiment.

[0083] See also Figure 2 The power system transient simulation method based on virtual admittance provided in this embodiment includes the following simulation process:

[0084] Obtain the node voltage V and phase angle value of each dynamic element in the power system at the current moment , use the phase angle value to perform the following vector decomposition on the x-axis and y-axis to obtain the voltage components:

[0085]

[0086] in, and Represents the node voltage The x-axis and y-axis components of Indicates the phase angle value.

[0087] In the first iteration of each time step of transient simulation, the virtual admittance of each dynamic element is calculated.

[0088] Firstly, based on the linear sensitivity method, the voltage component and Set the disturbance amount separately and , the voltage component and Input the dynamic model of the dynamic element to obtain the injected current and ; Apply disturbance in the x-axis direction of node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the first node injection current component ; Apply a disturbance in the y-axis direction of the node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the second node injection current component .

[0089] The following set of equations is constructed based on the calculated node voltages and node injection currents:

[0090]

[0091]

[0092] Solving the above equations, we can obtain the virtual admittance matrix of each dynamic element. .

[0093] Among them, the virtual admittance matrix is a 2×2 matrix. Assuming that the system has m dynamic elements, the virtual admittance matrix is ​​obtained. , a small disturbance applied to the voltage and Should be less than 0.01.

[0094] The virtual admittance matrices of all dynamic elements in the power system are formed into diagonal block matrices, and the initial network equations are corrected using the diagonal block matrices according to the following relationship: Correction:

[0095]

[0096] Solve the above equation for , we get the new network equation, where represents the node admittance matrix of the power system, represents the node voltage vector, represents the node injection current vector, Represents the diagonal block matrix composed of the virtual admittance matrices of all dynamic elements, which has the following expression:

[0097]

[0098] Where n represents the number of dynamic elements in the power system, Represents the virtual admittance matrix of the nth dynamic element. For nodes in the system that have no dynamic elements connected, their virtual admittance is set to a zero matrix.

[0099] The network equation is used to perform transient simulation of the power system at the current time step until the simulation convergence condition is met. The simulation convergence condition for each time step is:

[0100]

[0101] Where k represents the number of iterations per time step, and They represent the node voltages at the kth and k-1th iterations in the same time step, Represents the convergence threshold.

[0102] The above-mentioned embodiments provide a method for transient simulation of power systems based on virtual admittance, wherein a corresponding virtual admittance matrix is ​​calculated according to the node voltage and phase angle value of each dynamic element at the current moment, and the network equation of the system is corrected using the virtual admittance matrix, thereby improving the convergence of transient simulation. The virtual admittance matrix is ​​used to simulate the real response of the dynamic elements, so that the system model can be equivalently transformed even in the absence of an explicit mathematical model of the element. In particular, for systems connected to the grid with new energy, an equivalent transformation of the simulation model of the entire system can be achieved with the goal of improving convergence, thereby solving the problem of non-convergence of the simulation.

[0103] In order to verify the effectiveness of the simulation method proposed in this application, an improved IEEE-9 node system is used as an example below. Based on the standard IEEE-9 node system, node 5 of the improved system is connected to a wind farm and node 6 is connected to a photovoltaic power station.

[0104] See also Figure 3 , which illustrates an improved IEEE-9 node system, on this basis, a wind farm is connected to node 5, and a photovoltaic power station is connected to node 6. The dynamic model of the new energy station in the system adopts the encapsulated DLL model provided by the manufacturer. The line faults in the system are analyzed by the time domain simulation method proposed in this application to obtain the dynamic response of each node and each dynamic element in the whole system.

[0105] Figures 4 to 6The node voltage test results of the wind farm, photovoltaic power station and synchronous generator of node 1 are shown respectively. Figure 7-8 The simulation iteration results of the node voltage at the wind farm grid connection point and the photovoltaic power station grid connection point in the first time step after the system failure are respectively illustrated. It can be clearly seen from the simulation results that, by adopting the simulation method proposed in this application, the algorithm can quickly converge to the final solution of the system model at that time step during the iterative calculation process of each time step, while in the case where the method proposed in this application is not adopted, the difference between two adjacent iterative calculations in the algorithm solution process becomes larger and larger, and the simulation results eventually diverge, resulting in the inability to continue the simulation.

[0106] The above disclosed embodiment describes in detail a method for transient simulation of an electric power system based on virtual admittance. The above disclosed method can be implemented using various forms of equipment. Therefore, the present invention also discloses a device for transient simulation of an electric power system based on virtual admittance corresponding to the above method. A specific embodiment is given below for detailed description.

[0107] like Fig. 9 As shown, an embodiment of the present invention provides a power system transient simulation device based on virtual admittance, comprising:

[0108] The data acquisition module 902 is used to obtain the node voltage and phase angle value of each dynamic element in the power system to be simulated at the current moment;

[0109] A virtual admittance calculation module 904 is used to calculate the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculate the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element;

[0110] A network equation correction module 906, used to correct the network equation of the current time step using a virtual admittance matrix;

[0111] The transient simulation module 908 is used to perform transient simulation of the power system at the current time step using the network equations until the simulation convergence condition is met.

[0112] The implementation principle and technical effects of the device provided in the embodiments of the present application are the same as those of the aforementioned method embodiments. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiments.

[0113] The following embodiments are described by taking the method applied to a computer device as an example. It can be understood that the computer device can be any device with computing and processing functions, and can be but not limited to a server or a personal laptop computer, etc. In one embodiment, the computer device can be an application server, and the application server can be a server for running an application to be tested.

[0114] See also Fig.10 , which shows a hardware block diagram of an electronic device, the electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present application described and / or required herein.

[0115] like Fig.10 As shown, the electronic device includes: at least one processor 1, at least one communication interface 2, at least one memory 3 and at least one communication bus 4;

[0116] In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 communicate with each other through the communication bus 4;

[0117] The processor 1 may be a central processing unit CPU, or an application-specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present invention, etc.;

[0118] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), etc., such as at least one disk memory;

[0119] The memory stores a program, and the processor can call the program stored in the memory, wherein the program is used to: implement various processing flows of the aforementioned power system transient simulation solution based on virtual admittance.

[0120] An embodiment of the present invention also provides a readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the computer program implements the various processing flows of the power system transient simulation solution based on virtual admittance provided in the above embodiment and / or any possible implementation method in combination with the embodiment.

[0121] The methods and related devices mentioned in the above embodiments are described with reference to the method flow charts and / or structural diagrams provided in the embodiments of the present application. Specifically, each process and / or block in the method flow charts and / or structural diagrams, as well as the combination of processes and / or blocks in the flow charts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process in the process. Figure 1 A process or multiple processes and / or structures Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or structures Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A flow or multiple flows and / or structures illustrate the steps of the functions specified in one block or multiple blocks.

[0122] The above-mentioned embodiments have described the present invention in particular detail with respect to possible scenarios, and those skilled in the art will recognize that the present invention can be practiced through other embodiments. The specific naming of components, the capitalization of terms, attributes, data structures, or any other programming or structural aspects are not mandatory or important, and the mechanisms or features of the present invention may have different names, forms, or procedures. The system may be implemented by a combination of hardware and software (as described), entirely by hardware elements, or entirely by software elements. The specific division of functions between the various system components described herein is exemplary only and not mandatory; on the contrary, the functions performed by a single system component may be performed by multiple components, or the functions performed by multiple components may be performed by a single component.

[0123] Those skilled in the art should understand that the various steps of the above disclosed method can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, optionally, they can be implemented with program codes executable by the computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0124] These computing device executable programs (also referred to as programs, software, software applications, or code) include machine instructions for programmable processors, and these computing programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, device, and / or device (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0125] Certain aspects of the present invention include process steps and instructions described herein in the form of algorithms. It should be noted that the process steps and instructions of the present invention can be implemented in software, firmware and / or hardware, and when implemented by software, it can be downloaded, stored on different platforms used by various operating systems and operated from the platforms.

[0126] Those skilled in the art will understand that the structures shown in the accompanying drawings are merely block diagrams of partial structures related to the scheme of the present application, and do not constitute a limitation on the terminal device to which the scheme of the present application is applied. The specific terminal device may include more or fewer components than those shown in the figures, or combine certain components, or have a different arrangement of components.

[0127] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "possible design" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0128] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0129] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for transient simulation of power system based on virtual admittance, characterized in that: include: Obtaining node voltage and phase angle values ​​of each dynamic element in the power system to be simulated at the current moment; Calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element; Using the virtual admittance matrix to correct the network equation of the current time step to obtain a new network equation; The new network equation is used to perform transient simulation of the power system at the current time step until the simulation convergence condition is met.

2. The method according to claim 1, characterized in that The step of calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element comprises: The node voltage is vector-decomposed using the phase angle value to obtain the voltage component; The disturbance value is set for the voltage component, and the voltage component and the disturbance value are input into the dynamic model of the dynamic element for calculation, so as to obtain the node injection current component corresponding to each voltage component.

3. The method according to claim 2, characterized in that The step of using the phase angle value to perform vector decomposition on the node voltage to obtain the voltage component comprises: The node voltage is vector-decomposed on the x-axis and y-axis using the phase angle value. The specific decomposition is as follows: in, and Represents the node voltage The x-axis and y-axis components of Indicates the phase angle value.

4. The method according to claim 2, characterized in that: The disturbance amount is set for each voltage component, and the voltage component and the disturbance amount are input into the dynamic model of the dynamic element for calculation, so as to obtain the node injection current component corresponding to each voltage component, including: Based on the linear sensitivity method, the voltage component and Set the disturbance amount separately and ; The voltage component and Input the dynamic model of the dynamic element to obtain the injected current and ; Apply a disturbance in the x-axis direction of the node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the first node injection current component ; Apply a disturbance in the y-axis direction of the node voltage ,Bundle The dynamic model of the dynamic element is input as a variable to obtain the second node injection current component .

5. The method according to claim 4, characterized in that The step of calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element comprises: The following system of equations is constructed using the voltage components and node injection current components: Solve the equations to get the virtual admittance matrix of each dynamic element .

6. The method according to claim 1, characterized in that The network equation for correcting the current time step by using the virtual admittance matrix includes: The virtual admittance matrices of all dynamic elements in the power system are formed into diagonal block matrices; The initial network equation is transformed using the diagonal block matrix according to the following relationship: Correction: Solve the relationship , we get the new network equation, where represents the network admittance matrix of the power system, represents the node voltage vector, represents the node injection current vector, Represents the diagonal block matrix composed of the virtual admittance matrices of all dynamic elements, which has the following expression: Where n represents the number of dynamic elements in the power system, Represents the virtual admittance matrix of the nth dynamic element.

7. The method according to claim 1, characterized in that The simulation convergence conditions include: Where k represents the number of iterations per time step, and They represent the node voltages at the kth and k-1th iterations in the same time step, Represents the convergence threshold.

8. A power system transient simulation device based on virtual admittance, characterized in that: include: A data acquisition module is used to obtain the node voltage and phase angle value of each dynamic element in the power system to be simulated at the current moment; The virtual admittance calculation module is used to perform the virtual admittance matrix calculation process in the first iteration calculation of the current time step. The virtual admittance matrix calculation process includes: Calculating the node injection current of each dynamic element based on the node voltage and phase angle value of each dynamic element, and calculating the virtual admittance matrix of each dynamic element according to the node voltage and node injection current of each dynamic element; A network equation correction module, used for correcting the network equation of the current time step by using the virtual admittance matrix; The transient simulation module is used to perform transient simulation of the power system at the current time step using the network equations until the simulation convergence conditions are met.

9. An electronic device, characterized in that: The device comprises a memory storing computer executable instructions and a processor. When the computer executable instructions are executed by the processor, the device executes the power system transient simulation method based on virtual admittance as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: A computer executable program is stored, and when the program is executed, the method for transient simulation of a power system based on virtual admittance as described in any one of claims 1 to 7 can be implemented.

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