A method, system, device and simulation method for constructing an electromagnetic transient simulation model

Abstract

The application relates to an electromagnetic transient simulation model construction method, a simulation method, a system and equipment, the construction method constructs an equivalent circuit of a high-voltage direct-current direct-hanging energy storage device under normal working conditions through the topological structure of a single sub-module and the operation mode of the single sub-module under normal working conditions, constructs a locking loop based on the operation mode of the single sub-module under a locking condition, and constructs an electromagnetic transient simulation model based on the equivalent circuit and the locking loop, the equivalent circuit and the locking loop can be respectively constructed according to the operation working condition and the internal dynamic characteristics of the sub-module, the energy storage component is avoided from being directly simplified into a voltage source, the internal characteristics of the high-voltage direct-current direct-hanging energy storage device under multiple working conditions can be accurately simulated by the constructed electromagnetic transient simulation model, the simulation accuracy and the speed-up effect are good under the locking working condition and the normal working condition, and the subsequent control strategy, inertia active support and fault ride-through can be conveniently researched.

Description

Technical Field

[0001] This invention relates to the field of novel energy storage technology, specifically to a method for constructing an electromagnetic transient simulation model, a simulation method, a system, and equipment. Background Technology

[0002] Currently, the energy supply structure is transitioning from being dominated by thermal power to being dominated by new energy sources. However, due to the intermittency and uncertainty of new energy output, problems such as reduced grid connection reliability, reduced system inertia, and decreased power quality have arisen. Against this backdrop, the demand for flexibility across multiple time scales in new power systems is constantly increasing, and the application of energy storage technology in power systems is developing rapidly.

[0003] Electrochemical batteries and supercapacitors are the main representatives of energy storage technology. Due to their limited cycle life and low power density, energy storage batteries restrict their application in inertial response. In contrast, supercapacitors have advantages such as high power density, fast response speed, and long cycle life, making them particularly suitable for applications such as inertial response and transient voltage support. With the development of power electronics technology, energy storage topologies have become more diverse. Among them, the construction of a single-unit large-capacity supercapacitor energy storage system (SESS) by combining supercapacitors with high-voltage chain circuits has become a research hotspot in both academic and industrial circles at home and abroad. This mainly includes two implementation methods: connecting the supercapacitor inside a modular multilevel converter (MMC) submodule. Energy storage-type MMCs greatly improve their long-term active inertial support and fault ride-through capabilities. However, the high coupling of supercapacitor energy storage within the MMC submodule generates additional second-harmonic and fundamental frequency current components, and its effect is limited in multi-terminal flexible DC systems. Another technical approach is to configure an independent DC direct-mounted energy storage device (HVDCDM-SESS) on the high voltage DC side. This approach has advantages in power decoupling control, online commissioning and decommissioning, energy storage capacity configuration, and multi-terminal energy storage support.

[0004] Because HVDCDM-SESS contains a large number of switching devices and energy storage devices, and the number of sub-modules in high-voltage systems usually reaches several hundred, the electromagnetic transient simulation of detailed models of HVDCDM-SESS is inefficient. In current simulation speed-up studies, the average value equivalent model cannot reflect the internal electrical quantities of the converter. Summary of the Invention

[0005] To address the problem in existing technologies where equivalent modeling simplifies the energy storage device of a high-voltage direct-connected energy storage device to a voltage source, failing to accurately characterize the internal dynamic characteristics and operational behavior of sub-modules, this invention proposes an electromagnetic transient simulation model construction method, simulation method, system, equipment, and storage medium.

[0006] In a first aspect, the present invention provides a method for constructing an electromagnetic transient simulation model, applicable to high-voltage direct-connected energy storage devices, the method comprising: By analyzing the energy storage access method of the high-voltage direct-connected energy storage device, the topology of a single sub-module in the high-voltage direct-connected energy storage device and the operating modes of the single sub-module under different operating conditions are determined. The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodule. Based on the topology of the individual submodule and the operating mode of the individual submodule under normal operating conditions, the equivalent circuit of the high voltage DC direct-connected energy storage device under normal operating conditions is constructed. Based on the operating mode of the individual submodule under the interlocking condition, an interlocking loop is constructed; Based on the equivalent circuit and the blocking loop, an electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device is constructed.

[0007] Optionally, constructing the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the topology of the individual submodule and the operating mode of the individual submodule under normal operating conditions includes: Based on the topology of the individual submodule, construct the topology of each individual submodule. RL Differential equations for series branches and capacitor branches; Based on the single submodule RL The differential equations of the series branches are discretized using a pre-defined numerical integration algorithm to obtain... RL Discretized adjoint model of inductance in series branch; Based on the differential equation of the capacitor branch in the single submodule, a preset numerical integration algorithm is used to discretize the equation, and a discretized adjoint model of the capacitor in the capacitor branch is obtained. Based on the operating mode of the individual submodule under normal working conditions, the modeling method of the switch group is selected; Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the modeling method of the switch group, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions is constructed.

[0008] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The RL The discretized adjoint model of the inductor in a series branch satisfies the following formula:

[0009]

[0010]

[0011] In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, h Let be the step size of the trapezoidal integral algorithm. for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. L For inductance, R For series resistance, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, G TLR For discretization RL The equivalent conductance of a series branch, J TLRn As the historical current source in the equivalent circuit, R TLR For discretization RL The equivalent resistance of a series branch. E TLRn for RL The historical voltage source of the series branch in the equivalent circuit.

[0012] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The discretized adjoint model of the capacitor in the capacitor branch satisfies the following formula:

[0013] In the formula, C For capacitors, i n for t n The current flowing through the capacitor branch at all times. i n+1 for t n+1 The current flowing through the capacitor branch at all times. u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This represents the historical current source of the capacitor branch in the equivalent circuit. R TC This is the equivalent resistance of the discretized capacitor. E TCn This represents the historical voltage source of the capacitor in the equivalent circuit.

[0014] Optionally, the switch group modeling method adopts the binary resistance method of switch groups; The discretized adjoint model based on the inductor, the discretized adjoint model based on the capacitor, and the modeling method of the switch group are used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions, including: Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the binary resistance method of the switch group, the equivalent circuit of a single sub-module in the high voltage DC direct-connected energy storage device is obtained. By utilizing the topology of the high-voltage direct-connected energy storage device, the equivalent circuits of the individual sub-modules are superimposed to obtain the equivalent circuit of the high-voltage direct-connected energy storage device under normal operating conditions.

[0015] Optionally, the equivalent circuit of a single submodule in the high-voltage DC direct-connected energy storage device satisfies the following formula:

[0016] In the formula, u sm ( t )for t The port voltage of the time submodule, R smeq This is the equivalent resistance after the submodule is equivalent. i sm ( t )for t The port current of the time submodule, E smeq ( th () is the equivalent historical voltage source. h This is the step size for the trapezoidal integral algorithm.

[0017] Optionally, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions satisfies the following formula:

[0018] In the formula, u arm ( t )for t The port voltage of the energy storage bridge arm at all times. i arm ( t )for t The port current of the energy storage bridge arm at all times. The first in the energy storage bridge arm i Port voltage of each submodule The first in the energy storage bridge arm i The equivalent resistance of each submodule The first in the energy storage bridge arm i The equivalent historical voltage source of each submodule R arm The equivalent resistance of the energy storage bridge arm. E arm ( th () is the equivalent historical voltage source of the energy storage bridge arm. N This represents the number of submodules.

[0019] Optionally, constructing the interlocking loop based on the operating mode of the individual submodule under the interlocking condition includes: The operating modes of the individual submodule under the locked-out condition are analyzed, and the individual submodule is divided into a half-bridge submodule and an energy storage submodule. Based on the capacitor voltage of the energy storage submodule and the capacitor voltage of the half-bridge submodule, a closed-loop sub-model of the energy storage submodule is constructed. The lockout circuit sub-model of the energy storage sub-module is used as the lockout circuit.

[0020] A second aspect of the present invention also provides an electromagnetic transient simulation model construction system, applicable to high-voltage direct-connected energy storage devices, the construction system comprising: The energy storage access mode analysis unit is used to analyze the energy storage access mode of the high voltage DC direct-connected energy storage device to determine the topology of a single sub-module in the high voltage DC direct-connected energy storage device, as well as the operating mode of the single sub-module under different operating conditions. The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodule. An equivalent circuit construction unit is used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the topology of the individual sub-module and the operating mode of the individual sub-module under normal operating conditions. A locking loop construction unit is used to construct a locking loop based on the operating mode of the single submodule under locking conditions; The electromagnetic transient simulation model construction unit is used to construct the electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device based on the equivalent circuit and the blocking circuit.

[0021] Optionally, the equivalent circuit building unit includes: The differential equation construction module is used to construct the differential equations in each of the individual submodules based on their topological structure. RL Differential equations for series branches and capacitor branches; The first adjoint model determination module is used to determine the model based on the individual submodule. RL The differential equations of the series branches are discretized using a pre-defined numerical integration algorithm to obtain... RL Discretized adjoint model of inductance in series branch; The second adjoint model determination module is used to discretize the differential equation of the capacitor branch in the single submodule using a preset numerical integration algorithm to obtain the discretized adjoint model of the capacitor in the capacitor branch. The modeling method selection module is used to select the modeling method for the switch group based on the operating mode of the individual sub-module under normal working conditions; The equivalent circuit construction module is used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the modeling method of the switch group.

[0022] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The RL The discretized adjoint model of the inductor in a series branch satisfies the following formula:

[0023]

[0024]

[0025] In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, h Let be the step size of the trapezoidal integral algorithm. for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. L For inductance, R For series resistance, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, G TLR For discretization RL The equivalent conductance of a series branch, J TLRn As the historical current source in the equivalent circuit, R TLR For discretization RL The equivalent resistance of a series branch. E TLRn for RL The historical voltage source of the series branch in the equivalent circuit.

[0026] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The discretized adjoint model of the capacitor in the capacitor branch satisfies the following formula:

[0027] In the formula,C For capacitors, i n for t n The current flowing through the capacitor branch at all times. i n+1 for t n+1 The current flowing through the capacitor branch at all times. u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This represents the historical current source of the capacitor branch in the equivalent circuit. R TC This is the equivalent resistance of the discretized capacitor. E TCn This represents the historical voltage source of the capacitor in the equivalent circuit.

[0028] Optionally, the switch group modeling method adopts the binary resistance method of switch groups; The equivalent circuit construction module is specifically used for: Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the binary resistance method of the switch group, the equivalent circuit of a single sub-module in the high voltage DC direct-connected energy storage device is obtained. By utilizing the topology of the high-voltage direct-connected energy storage device, the equivalent circuits of the individual sub-modules are superimposed to obtain the equivalent circuit of the high-voltage direct-connected energy storage device under normal operating conditions.

[0029] Optionally, the equivalent circuit of a single submodule in the high-voltage DC direct-connected energy storage device satisfies the following formula:

[0030] In the formula, u sm ( t )for t The port voltage of the time submodule, Rsmeq This is the equivalent resistance after the submodule is equivalent. i sm ( t )for t The port current of the time submodule, E smeq ( th () is the equivalent historical voltage source. h This is the step size for the trapezoidal integral algorithm.

[0031] Optionally, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions satisfies the following formula:

[0032] In the formula, u arm ( t )for t The port voltage of the energy storage bridge arm at all times. i arm ( t )for t The port current of the energy storage bridge arm at all times. The first in the energy storage bridge arm i Port voltage of each submodule The first in the energy storage bridge arm i The equivalent resistance of each submodule The first in the energy storage bridge arm i The equivalent historical voltage source of each submodule R arm The equivalent resistance of the energy storage bridge arm. E arm ( th () is the equivalent historical voltage source of the energy storage bridge arm. N This represents the number of submodules.

[0033] Optionally, the locking loop construction unit is specifically used for: The operating modes of the individual submodule under the locked-out condition are analyzed, and the individual submodule is divided into a half-bridge submodule and an energy storage submodule. Based on the capacitor voltage of the energy storage submodule and the capacitor voltage of the half-bridge submodule, a closed-loop sub-model of the energy storage submodule is constructed. The lockout circuit sub-model of the energy storage sub-module is used as the lockout circuit.

[0034] A third aspect of the present invention also provides an electromagnetic transient simulation method applicable to high-voltage direct-connected energy storage devices, the method comprising: Acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; Based on the switching signal, the equivalent circuit in the electromagnetic transient simulation model is used to simulate the normal operating condition of the high voltage DC direct-connected energy storage device, and the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions is obtained. Based on the switching signal and the blocking signal, the blocking circuit in the electromagnetic transient simulation model is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device, and the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition is obtained. Based on the first simulation results and the second simulation results, the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device are obtained; The electromagnetic transient simulation model is a pre-constructed electromagnetic transient simulation model using the construction method described above, and the electromagnetic transient simulation model is connected to an external DC power supply.

[0035] A fourth aspect of the present invention also provides an electromagnetic transient simulation system suitable for high-voltage direct-connected energy storage devices, the system comprising: The signal acquisition unit is used to acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; The first simulation unit is used to simulate the normal operating conditions of the high voltage DC direct-connected energy storage device based on the switching signal and using the equivalent circuit in the electromagnetic transient simulation model, so as to obtain the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions. The second simulation unit is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device based on the switching signal and the blocking signal, using the blocking circuit in the electromagnetic transient simulation model, and to obtain the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition. The simulation result determination unit is used to obtain the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device based on the first simulation results and the second simulation results; The electromagnetic transient simulation model is a pre-constructed electromagnetic transient simulation model using the construction method described above.

[0036] A fifth aspect of the present invention also provides a computing device, comprising: one or more processors; A processor is used to execute one or more programs; When the one or more programs are executed by the one or more processors, an electromagnetic transient simulation model construction method as described above, or an electromagnetic transient simulation method as described above, is implemented.

[0037] In a sixth aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, it implements an electromagnetic transient simulation model construction method as described above, or an electromagnetic transient simulation method as described above.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method, system, and device for constructing an electromagnetic transient simulation model. The method constructs an equivalent circuit for a high-voltage direct-connected energy storage device under normal operating conditions by using the topology of a single submodule and its operating modes under normal conditions. Based on the operating modes of a single submodule under locked-out conditions, a lockout loop is constructed. Based on the equivalent circuit and the lockout loop, an electromagnetic transient simulation model of the high-voltage direct-connected energy storage device is constructed. This method allows for the construction of equivalent circuits and lockout loops for different operating conditions and internal dynamic characteristics of the submodules, avoiding the direct simplification of the energy storage components of the high-voltage direct-connected energy storage device as a voltage source. This enables the constructed electromagnetic transient simulation model to accurately simulate the internal characteristics of the high-voltage direct-connected energy storage device under multiple operating conditions. Furthermore, it exhibits good simulation accuracy and speed-up effects under both locked-out and normal operating conditions, facilitating subsequent research on control strategies, active inertia support, and fault ride-through. Attached Figure Description

[0039] Figure 1 A flowchart of an electromagnetic transient simulation model construction method provided by the present invention; Figure 2 This invention provides an HVDCDM-SESS submodule topology diagram; Figure 3 A schematic diagram illustrating the normal and locked operating modes of an HVDCDM-SESS submodule provided by this invention; Figure 4 This invention provides a discretized adjoint model for an inductor-resistor series branch; Figure 5 A discretized adjoint model of a capacitor branch is provided for this invention; Figure 6 The present invention provides an equivalent circuit of the discretized HVDCDM-SESS submodule and a schematic diagram of its Thevenin equivalent circuit. Figure 7 The Venin equivalent circuit for the entire bridge arm is provided by the present invention; Figure 8 A locking circuit for a submodule provided by the present invention; Figure 9 This invention provides an equivalent custom component for a half-bridge + energy storage system module; Figure 10 A block diagram of an electromagnetic transient simulation model construction system provided by the present invention; Figure 11 A simulation diagram of connecting an HVDCDM-SESS device to two ends of an 840kV DC power supply in PSCAD, provided for the present invention; Figure 12 A schematic diagram illustrating the simulation results of a detailed model and an equivalent model of an HVDCDM-SESS device containing 10 sub-modules in PSCAD, provided by the present invention. Figure 13 A block diagram of a computer device provided by the present invention. Detailed Implementation

[0040] Example 1: Figure 1 The flowchart provided by this invention illustrates a method for constructing an electromagnetic transient simulation model, applicable to high-voltage direct-connected energy storage devices, such as... Figure 1 As shown, the construction method may include the following steps 101 to 104: In step 101, by analyzing the energy storage access method of the high-voltage direct-connected energy storage device, the topology of a single sub-module in the high-voltage direct-connected energy storage device and the operating modes of the single sub-module under different operating conditions are determined.

[0041] The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodules.

[0042] In step 102, based on the topology of the individual submodule and the operating mode of the individual submodule under normal operating conditions, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions is constructed.

[0043] In step 103, a locking loop is constructed based on the operating mode of the single submodule under the locking condition.

[0044] In step 104, an electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device is constructed based on the equivalent circuit and the blocking loop.

[0045] In some scenarios, an electromagnetic transient simulation model construction method can also be referred to as a rapid electromagnetic transient simulation model construction method for HVDC direct-connected energy storage modules, or a rapid electromagnetic transient simulation model construction method for HVDCDM-SESS.

[0046] It should be noted that, for the "half-bridge + bidirectional DC / DC + supercapacitor" topology of the HVDCDM-SESS submodule, an electromagnetic transient simulation model is constructed; based on the binary resistance method of switching devices and the discretized adjoint model method, trapezoidal integral discretization is performed on the inductor and capacitor to obtain their equivalent conductance and historical current source. Combining the above methods, the Thevenin equivalent circuit of a single submodule (i.e., Thevenin The equivalent circuit is obtained by further cascading and combining the equivalent circuits of the entire bridge arm; for the locked-out condition, the locked-out circuit models of the half-bridge part and the energy storage system part are established respectively to achieve integration with the normal operating condition model; in the PSCAD / EMTDC platform, the above equivalent model is implemented based on custom component programming and embedded into the simulation system for fast electromagnetic transient simulation. The HVDCDM-SESS submodule topology includes a front-end half-bridge module and a back-end energy storage module. The energy storage module consists of a supercapacitor and a bidirectional DC / DC converter, and has flexible voltage level design capabilities.

[0047] The HVDCDM-SESS simulation platform interface module is used to implement custom component packaging and simulation operation in PSCAD / EMTDC. The system supports unified modeling under normal and locked operating conditions, and can significantly improve the electromagnetic transient simulation efficiency of large-scale HVDCDM-SESS systems while ensuring simulation accuracy.

[0048] above Figure 1 Possible implementations of step 102 shown may include steps 1021 to 1025: In step 1021, based on the topology of the individual submodule, the components of the individual submodule are constructed respectively. RL Differential equations for series branches and capacitor branches.

[0049] In step 1022, based on the single submodule RL The differential equations of the series branches are discretized using a pre-defined numerical integration algorithm to obtain... RL Discretized adjoint model of inductance in series branch.

[0050] In step 1023, based on the differential equation of the capacitor branch in the single submodule, a preset numerical integration algorithm is used to discretize the equation, thereby obtaining the discretized adjoint model of the capacitor in the capacitor branch.

[0051] In step 1024, the switch group modeling method is selected based on the operating mode of the individual submodule under normal operating conditions.

[0052] In step 1025, based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the modeling method of the switch group, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions is constructed.

[0053] The preset numerical integration algorithm is the trapezoidal integration algorithm. The switch group modeling method adopts the binary resistance method of switch groups.

[0054] The RL The discretized adjoint model of the inductor in a series branch satisfies the following formula:

[0055]

[0056]

[0057] In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, h Let be the step size of the trapezoidal integral algorithm. for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. L For inductance, R For series resistance, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, G TLR For discretization RL The equivalent conductance of a series branch, J TLRn As the historical current source in the equivalent circuit, R TLR For discretization RLThe equivalent resistance of a series branch. E TLRn for RL The historical voltage source of the series branch in the equivalent circuit.

[0058] The discretized adjoint model of the capacitor in the capacitor branch satisfies the following formula:

[0059] In the formula, C For capacitors, i n for t n The current constantly flowing through the capacitor branch, i n+1 for t n+1 The current constantly flowing through the capacitor branch, u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This represents the historical current source of the capacitor branch in the equivalent circuit. R TC This is the equivalent resistance of the discretized capacitor. E TCn This represents the historical voltage source of the capacitor in the equivalent circuit.

[0060] The specific implementation of step 1025 above may include the following steps S1 to S2: In step S1, based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the binary resistance method of the switch group, the equivalent circuit of a single submodule in the high voltage DC direct-connected energy storage device is obtained.

[0061] In step S2, the equivalent circuits of the individual sub-modules are superimposed using the topology of the high-voltage direct-connected energy storage device to obtain the equivalent circuit of the high-voltage direct-connected energy storage device under normal operating conditions.

[0062] The equivalent circuit of a single submodule in the high-voltage DC direct-connected energy storage device satisfies the following formula:

[0063] In the formula, u sm ( t )for t The port voltage of the time submodule, R smeq This is the equivalent resistance after the submodule is equivalent. i sm ( t )for t The port current of the time submodule, E smeq ( th () is the equivalent historical voltage source. h This is the step size for the trapezoidal integral algorithm.

[0064] The equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions satisfies the following formula:

[0065] In the formula, u arm ( t )for t The port voltage of the energy storage bridge arm at all times. i arm ( t )for t The port current of the energy storage bridge arm at all times. The first in the energy storage bridge arm i Port voltage of each submodule The first in the energy storage bridge arm i The equivalent resistance of each submodule The first in the energy storage bridge arm i The equivalent historical voltage source of each submodule R arm The equivalent resistance of the energy storage bridge arm. E arm ( th () is the equivalent historical voltage source of the energy storage bridge arm. N This represents the number of submodules.

[0066] It should be noted that by using the discretized adjoint model of inductance and capacitance, and the binary resistance method of the switch group to perform equivalent modeling of the high voltage DC direct-connected energy storage device, the power electronic components and switch group are converted into resistance and voltage source branches, which improves the simulation speed, facilitates large-scale simulation, and can calculate the internal electrical quantities through specific topology, thus preserving the internal electrical characteristics of the module.

[0067] above Figure 1 Possible implementations of step 103 shown may include the following steps 1031 to 1033: In step 1031, the operating modes of the single submodule under the locked-out condition are analyzed, and the single submodule is divided into a half-bridge submodule and an energy storage submodule.

[0068] In step 1032, a closed-loop sub-model of the energy storage submodule is constructed based on the capacitor voltage of the energy storage submodule and the capacitor voltage of the half-bridge submodule.

[0069] In step 1033, the lockout circuit sub-model of the energy storage sub-module is used as the lockout circuit.

[0070] The energy storage submodule consists of a capacitor and a bidirectional DC / DC converter.

[0071] Current research on DC-connected energy storage systems primarily employs detailed submodule models for electromagnetic transient simulation. The test system voltage levels are typically tens of kilovolts, with dozens of submodules. However, for high-voltage DC systems at the hundred-kilovolt level, these detailed models suffer from large simulation scale and low computational efficiency, failing to meet the demands for rapid system-level simulation. Regarding equivalent modeling, existing methods simplify the energy storage device as a voltage source, which reduces simulation complexity to some extent but cannot accurately characterize the internal dynamic characteristics and operational behavior of the submodules. Furthermore, research on rapid electromagnetic transient simulation models for other power electronic devices mainly focuses on the equivalent modeling of energy storage devices and MMC submodules. These differ from DC-connected energy storage systems in terms of submodule topology, operating mechanisms, and control methods, making direct applicability difficult.

[0072] The purpose of this invention is to overcome the shortcomings of the existing technology by proposing a fast electromagnetic transient simulation model construction method for HVDCDM-SESS. The provided fast electromagnetic transient simulation method is applicable to HVDC direct-connected energy storage technology based on a modular half-bridge-bidirectional DC / DC cascade topology. It proposes equivalent models of HVDCDM-SESS under normal operation and locked-out conditions. While ensuring acceleration, it can accurately simulate the external and internal characteristics of HVDCDM-SESS under multiple operating conditions, facilitating research on subsequent control strategies, active inertia support, and fault ride-through. In other words, it is an equivalent modeling method for HVDCDM-SESS that, while ensuring simulation speed, can simulate the internal and external characteristics of HVDCDM-SESS under multiple operating conditions, facilitating research on control strategies or fault characteristics.

[0073] For example, a method for constructing a rapid electromagnetic transient simulation model for a high-voltage direct-connected energy storage module includes the following steps in its multi-condition electromagnetic transient equivalent modeling method: Analyze the energy storage access method of HVDCDM-SESS, and select the topology and electromagnetic transient simulation model of supercapacitor according to the operating conditions; The topology of a single submodule of HVDCDM-SESS is as follows: Figure 2 As shown. The first half of the HVDCDM-SESS is a conventional half-bridge module, while the second half, the energy storage module, adopts a "half-bridge submodule + battery energy storage system" topology. To meet system modulation requirements and improve the utilization rate of supercapacitor energy, an additional DC / DC converter is usually required. Simultaneously, the voltage across the supercapacitor can differ from the DC bus voltage, thus offering significant flexibility in supercapacitor voltage level design and supercapacitor system design. After determining the submodule topology, the HVDCDM-SESS is constructed by cascading N submodules in parallel and connecting them in series with bridge arm inductors, according to different voltage levels. u sm ( t )for t The port voltage of the time submodule, i sm ( t )for t The current at the port of the submodule is measured at a given time. A and B represent the ports of the submodule, and D1, D2, D3, and D4 are the switch groups of the submodule. i C1 ( t )for t The current in the capacitor branch at any given time. U C1 This is the voltage across the capacitor in the capacitor branch. i C2 ( t )for t The current of the energy storage submodule at all times. U L This is the voltage across the inductor in the energy storage submodule. U C2 This is the voltage across the energy storage element in the energy storage submodule, which can be a supercapacitor.

[0074] Analyze the operating modes of HVDCDM-SESS, select a switch group modeling method, and verify its rationality.

[0075] The Thevenin equivalent circuit of the entire bridge arm includes the operating modes that the submodule may experience during HVDCDM-SESS operation, depending on the input current direction and switching signals. Figure 3 As shown. By Figure 3It can be seen that under normal controlled conditions of the submodule, the IGBT and diode in the switch group will not conduct simultaneously. Therefore, the switch group can be modeled using a binary resistor approach. The IGBT and its anti-parallel diode VD can be considered as a whole as a bidirectional switching switch (i.e., switch IGBT & VD), and thus can be regarded as a variable resistor controlled by switching commands. When IGBT & VD (i.e., the switch group) is on, its variable resistance takes a smaller value; when IGBT & VD is off, its variable resistance takes a larger value. For general electromagnetic transient simulation software, if the simulation purpose is not to calculate MMC losses, a variable resistance value of 0.01Ω in the IGBT & VD on-state and 1MΩ in the IGBT & VD off-state can achieve good results. C 1 represents the capacitor of the half-bridge submodule. L For inductance, C 2 is an energy storage element.

[0076] Based on the discretized adjoint model of capacitors and inductors and the binary resistor method of the switching group, the equivalent circuit of the sub-module is obtained, and thus the single sub-module is obtained. Thevenin Equivalent circuit, calculate the entire HVDCDM-SESS Thevenin Equivalent circuit.

[0077] Electromagnetic transient simulation programs for power systems typically employ the discretized adjoint model method for solution. The solution process of the discretized adjoint model method is as follows: ① First, select an appropriate numerical integration formula to discretize the differential equations describing the characteristics of individual components, forming a discretized adjoint model for each individual component; ② Based on the discretized adjoint model of each individual component, establish a discretized adjoint network for the entire power grid; ③ By solving the discretized adjoint network of the entire power grid, obtain the solution at a certain discrete time point; ④ Use the solution obtained at the current time to recursively derive the discretized adjoint model for the next discrete time point; Repeating steps ② to ④ yields the solution of the system at a series of discrete time points. The characteristic of the discretized adjoint model method is that it equates all distributed parameter components and lumped parameter energy storage components in the network to a combination of a conductor and a current source connected in parallel, thereby transforming the network equations described by differential equations into network equations described by algebraic equations, and converting the complex transient analysis problem of power networks into a relatively simple DC analysis problem of discretized adjoint networks.

[0078] The circuit after discretization of inductors and capacitors using the trapezoidal rule (i.e., the trapezoidal integral algorithm) is as follows: Figure 4 , Figure 5 As shown, where a) is the original circuit, b) Norton Discretization adjoint model, c) Thevenin Discretized adjoint model: First, the discretized adjoint model of the resistor-inductor series branch is derived. Description RLThe differential equation for the series branch is: or

[0079] In the formula, L For inductance, R For series resistance, i for t Time flows through the branch road ( RL The current in the series branch, u For both ends of the branch road t Voltage at a given moment.

[0080] If we use the trapezoidal rule for discretization, let the step size be... h ,but:

[0081]

[0082]

[0083] In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. G TLR For discretization RL The equivalent conductance of the branch, J TLRn This is the historical current source in the Norton equivalent circuit. R TLR For discretization RLThe equivalent resistance of the branch, E TLRn This is the historical voltage source in the Thevenin equivalent circuit.

[0084] The discretized adjoint model of the capacitor branch is derived below. The differential equation describing the capacitor branch is:

[0085] In the formula, C For capacitors, i for t The current constantly flowing through the capacitor branch, u For the two ends of the capacitor branch at t Voltage at a given moment.

[0086] If we use the trapezoidal rule for discretization, and let the step size be h, then:

[0087] In the formula, i n for t n The current flowing through the capacitor branch at all times. i n+1 for t n+1 The current flowing through the capacitor branch at all times. u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This is the historical current source in the Norton equivalent circuit. R TC This represents the equivalent resistance of the capacitor branch after discretization. E TCn This is the historical voltage source in the Thevenin equivalent circuit.

[0088] Under unlocked operating conditions (i.e., normal operating conditions), based on the Thevenin discretized adjoint model of the capacitor and inductor branches, the equivalent circuit diagram of the half-bridge submodule + energy storage system module can be obtained as follows: Figure 6 As shown. Among them R 1. R 2. R 3. R 4 represents the equivalent variable resistance of the upper and lower IGBT & VD switches (i.e., the switching group). From the AB ports, we can obtain the following... Figure 6 The Thevenin equivalent circuit shown:

[0089] in,

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] In the formula, u sm ( t ) represents the port voltage of the submodule. i sm ( t ) represents the port current of the submodule. R smeq For submodules Thevenin Equivalent resistance after conversion E smeq ( t - h ) is the equivalent historical voltage source for the submodule. R C1 , R C2 and R L For capacitor C 1. C 2 and inductance L The equivalent resistance after discretization using the trapezoidal rule. E C1 ( t - h ), E C2 ( t - h )andE L ( t - h ) is a capacitor C 1. C 2 and inductance L exist Thevenin Historical voltage sources in the equivalent circuit R A , R B These are the equivalent port resistances of the submodules. E eqLC ( t - h () is the equivalent historical voltage source for the energy storage submodule. U Ceq ( t - h ) represents the equivalent voltage of the submodule. R 1. R 2. R 3. R 4 represents the equivalent variable resistance of the switch group in the submodule.

[0096] In addition,

[0097]

[0098]

[0099]

[0100] In the formula, i sum ( t ) represents the current of the half-bridge submodule. i C1 ( t ), i C2 ( t ) are capacitors C 1. C 2 in Thevenin Current in the equivalent circuit i ( t () represents the current of the energy storage submodule. E C1 , E C2 and E L For capacitor C 1. C 2 and inductance L exist TheveninHistorical voltage sources in the equivalent circuit E eqLC This serves as the equivalent historical voltage source for the energy storage submodule. U Ceq This is the equivalent voltage of the submodule.

[0101] In obtaining a single submodule Thevenin After obtaining the equivalent circuit, the Thevenin equivalent circuit of the entire bridge arm can be determined. Let the entire bridge arm be... Thevenin Equivalent circuit such as Figure 7 As shown, the following derivation of the entire bridge arm of the high-voltage DC direct-connected energy storage system is presented. Thevenin Equivalent circuit.

[0102] One bridge arm (is composed of) N It is composed of several sub-modules connected in series. Therefore, the instantaneous output voltage of one arm is... u arm ( t (equal to all of this bridge arm) N Output port voltage of each submodule u sm ( t ), and i arm ( t )=i sm ( t ),Right now:

[0103]

[0104]

[0105] In the formula, u arm ( t () represents the instantaneous output voltage of the bridge arm. i arm ( t ) represents the instantaneous current of the bridge arm. For the first i Port voltage of each submodule For the first i Submodules Thevenin Equivalent resistance after conversion For the first i The equivalent historical voltage source of each submodule R arm For bridge arm Thevenin Equivalent resistance after conversion E arm ( t - h () represents the equivalent historical voltage source of the bridge arm. , The first i The equivalent variable resistance of a half-bridge sub-module switch group For the first i Equivalent port resistance of each submodule For the first i Equivalent voltage of each submodule N This represents the number of submodules.

[0106] The operating modes under the HVDCDM-SESS blocking condition were analyzed, the blocking loop was determined, and integrated with the equivalent model of the normal operating condition.

[0107] In the HVDCDM-SESS blocking condition modeling, during the HVDCDM-SESS startup phase, the IGBTs in the switchgear need to be blocked, and the capacitor is charged only through diode conduction. Under the blocking condition, the switchgear no longer satisfies the binary resistance method modeling approach; a separate equivalent model needs to be established for the blocking condition. Figure 3 The HVDCDM-SESS submodule's operation under locked-down conditions, as shown, can be divided into a half-bridge section (i.e., the half-bridge submodule) and an energy storage system section composed of a supercapacitor and a bidirectional DC / DC circuit (i.e., the energy storage submodule), which will be analyzed separately. The half-bridge section operates in two main states under locked-down conditions: ① charging the capacitor via diode D1; ② disconnecting (or bypassing) the submodule via diode D2. The locked-down operating states of the half-bridge submodule can be determined by adding parameters such as... to the equivalent model. Figure 8 The lockout circuit shown is implemented. The lockout operation state of the energy storage system mainly depends on the voltage relationship between the supercapacitor and the half-bridge module capacitor. ① If the supercapacitor voltage is lower than the half-bridge module capacitor voltage, diodes D3 and D4 cannot conduct. At this time, switch groups 3 and 4 are considered to be off, equivalent to a large resistance. ② Conversely, D3 conducts, the supercapacitor discharges to the half-bridge module capacitor. At this time, switch group 3 is equivalent to a small resistance, and switch group 4 is equivalent to a large resistance. The lockout condition of the energy storage system can be adjusted by observing the current flowing through the supercapacitor. When the current direction of the supercapacitor is from the supercapacitor to the half-bridge module capacitor, the supercapacitor discharges to the half-bridge module capacitor. When the current is below 0, all switch groups of the energy storage system are off, approximating an open circuit. Since the sub-modules in the bridge arm are cascaded, the current flowing into each sub-module is the same. Therefore, a lockout circuit identical to the sub-module lockout circuit is added to the bridge arm equivalent model to simulate the lockout condition of each sub-module. Deblk This is the interlock signal.

[0108] Based on the equivalent model established above, create custom components in PSCAD / EMTDC to realize their electrical functions.

[0109] A custom equivalent component for a half-bridge + energy storage system module created in PSCAD, such as... Figure 9 As shown. The input signals are the switching signals for the upper and lower IGBT & VD transistors. up 1. down 1. up 2. down 2) Lockout signal Deblk The output signal is the capacitor voltage. U C1 , U C2 C2 capacitor current I C2 Right now I L (Since both are the same in series), the inductor voltage serves as the signal for the control circuit. U L and C 1. Capacitor current I C1 As an observation signal, the specific code is divided into three parts: Branch road information settings The Branch code segment constructs the various branches of the lockout loop and the equivalent circuit, unifying the lockout loop into the model for easier simulation modeling.

[0110] Begin code snippet settings Initialize each branch, setting up the voltage sources, diodes, and IGBT components on each branch. Calculate the discretized resistance and admittance values ​​of the capacitors and inductors.

[0111] Equivalent circuit calculation Based on the discretized equivalent circuit, programmatically calculate each electrical quantity and distinguish between the equivalent circuits of the locked-out and normal operating conditions.

[0112] Compared with the prior art, the present invention has the following advantages: 1. This invention performs equivalent modeling of HVDCDM-SESS based on the discretized adjoint model, converting power electronic components and switches into resistor and voltage source branches, which improves the simulation speed, facilitates large-scale simulation, and allows the internal electrical quantities to be calculated through specific topology, thus preserving the internal electrical characteristics of the module.

[0113] 2. The HVDCDM-SESS equivalent model established in this invention has good simulation accuracy and speed-up effect under both locking and unlocking conditions.

[0114] Example 2: Figure 10 This invention provides a block diagram of an electromagnetic transient simulation model construction system, applicable to high-voltage direct-connected energy storage devices, such as... Figure 10As shown, the construction system includes: The energy storage access mode analysis unit is used to analyze the energy storage access mode of the high voltage DC direct-connected energy storage device to determine the topology of a single sub-module in the high voltage DC direct-connected energy storage device, as well as the operating mode of the single sub-module under different operating conditions. The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodule. An equivalent circuit construction unit is used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the topology of the individual sub-module and the operating mode of the individual sub-module under normal operating conditions. A locking loop construction unit is used to construct a locking loop based on the operating mode of the single submodule under locking conditions; The electromagnetic transient simulation model construction unit is used to construct the electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device based on the equivalent circuit and the blocking circuit.

[0115] Optionally, the equivalent circuit building unit includes: The differential equation construction module is used to construct the differential equations in each of the individual submodules based on their topological structure. RL Differential equations for series branches and capacitor branches; The first adjoint model determination module is used to determine the model based on the individual submodule. RL The differential equations of the series branches are discretized using a pre-defined numerical integration algorithm to obtain... RL Discretized adjoint model of inductance in series branch; The second adjoint model determination module is used to discretize the differential equation of the capacitor branch in the single submodule using a preset numerical integration algorithm to obtain the discretized adjoint model of the capacitor in the capacitor branch. The modeling method selection module is used to select the modeling method for the switch group based on the operating mode of the individual sub-module under normal working conditions; The equivalent circuit construction module is used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the modeling method of the switch group.

[0116] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The RL The discretized adjoint model of the inductor in a series branch satisfies the following formula:

[0117]

[0118]

[0119] In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, h Let be the step size of the trapezoidal integral algorithm. for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. L For inductance, R For series resistance, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, G TLR For discretization RL The equivalent conductance of a series branch, J TLRn As the historical current source in the equivalent circuit, R TLR For discretization RL The equivalent resistance of a series branch. E TLRn for RL The historical voltage source of the series branch in the equivalent circuit.

[0120] Optionally, the preset numerical integration algorithm is a trapezoidal integration algorithm; The discretized adjoint model of the capacitor in the capacitor branch satisfies the following formula:

[0121] In the formula, C For capacitors, i n for tn The current constantly flowing through the capacitor branch, i n+1 for t n+1 The current constantly flowing through the capacitor branch, u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This represents the historical current source of the capacitor branch in the equivalent circuit. R TC This is the equivalent resistance of the discretized capacitor. E TCn This represents the historical voltage source of the capacitor in the equivalent circuit.

[0122] Optionally, the switch group modeling method adopts the binary resistance method of switch groups; The equivalent circuit construction module is specifically used for: Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the binary resistance method of the switch group, the equivalent circuit of a single sub-module in the high voltage DC direct-connected energy storage device is obtained. By utilizing the topology of the high-voltage direct-connected energy storage device, the equivalent circuits of the individual sub-modules are superimposed to obtain the equivalent circuit of the high-voltage direct-connected energy storage device under normal operating conditions.

[0123] Optionally, the equivalent circuit of a single submodule in the high-voltage DC direct-connected energy storage device satisfies the following formula:

[0124] In the formula, u sm ( t )for t The port voltage of the time submodule, R smeq This is the equivalent resistance after the submodule is equivalent. i sm ( t)for t The port current of the time submodule, E smeq ( th () is the equivalent historical voltage source. h This is the step size for the trapezoidal integral algorithm.

[0125] Optionally, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions satisfies the following formula:

[0126] In the formula, u arm ( t )for t The port voltage of the energy storage bridge arm at all times. i arm ( t )for t The port current of the energy storage bridge arm at all times. The first in the energy storage bridge arm i Port voltage of each submodule The first in the energy storage bridge arm i The equivalent resistance of each submodule The first in the energy storage bridge arm i The equivalent historical voltage source of each submodule R arm The equivalent resistance of the energy storage bridge arm. E arm ( th () is the equivalent historical voltage source of the energy storage bridge arm. N This represents the number of submodules.

[0127] Optionally, the locking loop construction unit is specifically used for: The operating modes of the individual submodule under the locked-out condition are analyzed, and the individual submodule is divided into a half-bridge submodule and an energy storage submodule. Based on the capacitor voltage of the energy storage submodule and the capacitor voltage of the half-bridge submodule, a closed-loop sub-model of the energy storage submodule is constructed. The lockout circuit sub-model of the energy storage sub-module is used as the lockout circuit.

[0128] Example 3: This invention also provides an electromagnetic transient simulation method applicable to high-voltage direct-connected energy storage devices, the method comprising: Acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; Based on the switching signal, the equivalent circuit in the electromagnetic transient simulation model is used to simulate the normal operating condition of the high voltage DC direct-connected energy storage device, and the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions is obtained. Based on the switching signal and the blocking signal, the blocking circuit in the electromagnetic transient simulation model is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device, and the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition is obtained. Based on the first simulation results and the second simulation results, the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device are obtained; The electromagnetic transient simulation model is a pre-constructed electromagnetic transient simulation model using the construction method described above, and the electromagnetic transient simulation model is connected to an external DC power supply.

[0129] like Figure 11 As shown, in PSCAD / EMTDC, this embodiment of the invention connects the HVDCDM-SESS device to both ends of an 840kV DC power supply. Each submodule has a voltage of 2kV, therefore 420 submodules are required. At this point, a 5-second simulation takes 2 minutes and 38 seconds, which is within acceptable speed limits. However, using a detailed model would prevent large-scale simulations. (The last sentence, "V," appears to be an error and is left untranslated.) step DC power supply U dc_th_v2 The voltage of the DC power supply. U sm_th_v2 The port voltage is the equivalent model. I sm_th_v2 For the port current of the equivalent model, equ_MMC This is an electromagnetic transient simulation model. ts1 _ up , ts1 _ down , ts2 _ up , ts2 _ down For the switching signals of the switch group, Deblk This is a blocking signal. U C1 , U C2 C2 is the capacitor voltage, and C2 is the capacitor current. I C2 , I L For inductor current, I C1 for C 1. Capacitor current.

[0130] In this embodiment of the invention, the HVDCDM-SESS device is connected to a 20 kV DC power supply. The device comprises 10 sub-modules, each with a voltage of 2 kV. The total simulation time is 5 s, and at t = 3 s, the DC voltage increases from 20 kV to 25 kV. To verify the accuracy of the proposed equivalent model, detailed models of the 10 sub-modules and the equivalent model are established and compared in simulation. The results are as follows: Figure 12 As shown. Simulation results show that under both locked and normal operating conditions, the detailed model and the equivalent model's results are basically consistent, verifying the accuracy of the equivalent model. With a simulation duration of 5 seconds for each, the detailed model of the 10 sub-modules takes 1 minute and 20 seconds to simulate, while the equivalent model only takes 53 seconds, improving simulation efficiency by approximately 33.8%. U sum For detailed model port voltage, U sm_th_v2 The port voltage is the equivalent model. I dc_pu For detailed model port current, I sm_th_v2 This represents the port current in the equivalent model.

[0131] Example 4: This invention also provides an electromagnetic transient simulation system suitable for high-voltage direct-connected energy storage devices, the system comprising: The signal acquisition unit is used to acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; The first simulation unit is used to simulate the normal operating conditions of the high voltage DC direct-connected energy storage device based on the switching signal and using the equivalent circuit in the electromagnetic transient simulation model, so as to obtain the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions. The second simulation unit is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device based on the switching signal and the blocking signal, using the blocking circuit in the electromagnetic transient simulation model, and to obtain the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition. The simulation result determination unit is used to obtain the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device based on the first simulation results and the second simulation results; The electromagnetic transient simulation model is a pre-constructed electromagnetic transient simulation model using the construction method described above.

[0132] Example 5: Based on the same inventive concept, the present invention also provides a computer device, such as... Figure 13As shown, the computer device includes a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the electromagnetic transient simulation model construction method or the electromagnetic transient simulation method in the above embodiments.

[0133] Example 6: Based on the same inventive concept, this invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and extended storage media supported by the computer device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the steps of the electromagnetic transient simulation model construction method or the electromagnetic transient simulation method described in the above embodiments.

[0134] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0135] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0136] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0137] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0138] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for constructing an electromagnetic transient simulation model, characterized in that, The construction method is applicable to high-voltage direct-connected energy storage devices and includes: By analyzing the energy storage access method of the high-voltage direct-connected energy storage device, the topology of a single submodule in the high-voltage direct-connected energy storage device and the operating modes of the single submodule under different operating conditions are determined. The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodule. Based on the topology of the individual submodule and the operating mode of the individual submodule under normal operating conditions, the equivalent circuit of the high voltage DC direct-connected energy storage device under normal operating conditions is constructed. Based on the operating mode of the individual submodule under the interlocking condition, an interlocking loop is constructed; Based on the equivalent circuit and the blocking loop, an electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device is constructed.

2. The method according to claim 1, characterized in that, The construction of the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions, based on the topology of the individual submodule and the operating mode of the individual submodule under normal operating conditions, includes: Based on the topology of the individual submodule, construct the individual submodules respectively. RL Differential equations for series branches and capacitor branches; Based on the single submodule RL The differential equations of the series branches are discretized using a pre-defined numerical integration algorithm to obtain... RL Discretized adjoint model of inductance in series branch; Based on the differential equation of the capacitor branch in the single submodule, a preset numerical integration algorithm is used to discretize the equation, and a discretized adjoint model of the capacitor in the capacitor branch is obtained. Based on the operating mode of the individual submodule under normal working conditions, the modeling method of the switch group is selected; Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the modeling method of the switch group, the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions is constructed.

3. The method according to claim 2, characterized in that, The preset numerical integration algorithm is the trapezoidal integration algorithm; The RL The discretized adjoint model of the inductor in a series branch satisfies the following formula: In the formula, i n+1 for t n+1 Time flows by RL The current in the series branch, i n for t n Time flows by RL The current in the series branch, h Let be the step size of the trapezoidal integral algorithm. for t n+1 Time flows by RL The first derivative of the current in the series branch with respect to time. for t n Time flows by RL The first derivative of the current in the series branch with respect to time. L For inductance, R For series resistance, u n for t n time RL The voltage across the series branch, u n+1 for t n+1 time RL The voltage across the series branch, G TLR For discretization RL The equivalent conductance of a series branch, J TLRn As the historical current source in the equivalent circuit, R TLR For discretization RL The equivalent resistance of a series branch. E TLRn for RL The historical voltage source of the series branch in the equivalent circuit.

4. The method according to claim 2, characterized in that, The preset numerical integration algorithm is the trapezoidal integration algorithm; The discretized adjoint model of the capacitor in the capacitor branch satisfies the following formula: In the formula, C For capacitors, i n for t n The current flowing through the capacitor branch at all times. i n+1 for t n+1 The current flowing through the capacitor branch at all times. u n for t n The voltage across the capacitor branch at any given time. u n+1 for t n+1 The voltage across the capacitor branch at any given time. for t n The first derivative of the voltage across the capacitive branch with respect to time. for t n+1 The first derivative of the voltage across the capacitor branch with respect to time at any given moment. G TC The equivalent conductance of the capacitor branch after discretization is given. J TCn This represents the historical current source of the capacitor branch in the equivalent circuit. R TC This is the equivalent resistance of the discretized capacitor. E TCn This represents the historical voltage source of the capacitor in the equivalent circuit.

5. The method according to claim 2, characterized in that, The modeling method for the switch group adopts the binary resistance method for the switch group. The discretized adjoint model based on the inductor, the discretized adjoint model based on the capacitor, and the modeling method of the switch group are used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions, including: Based on the discretized adjoint model of the inductor, the discretized adjoint model of the capacitor, and the binary resistance method of the switch group, the equivalent circuit of a single sub-module in the high voltage DC direct-connected energy storage device is obtained. By utilizing the topology of the high-voltage direct-connected energy storage device, the equivalent circuits of the individual sub-modules are superimposed to obtain the equivalent circuit of the high-voltage direct-connected energy storage device under normal operating conditions.

6. The method according to claim 5, characterized in that, The equivalent circuit of a single submodule in the high-voltage DC direct-connected energy storage device satisfies the following formula: In the formula, u sm ( t )for t The port voltage of the time submodule, R smeq This is the equivalent resistance after the submodule is equivalent. i sm ( t )for t The port current of the time submodule, E smeq ( th () is the equivalent historical voltage source. h This is the step size for the trapezoidal integral algorithm.

7. The method according to claim 5, characterized in that, The equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions satisfies the following formula: In the formula, u arm ( t )for t The port voltage of the energy storage bridge arm at all times. i arm ( t )for t The port current of the energy storage bridge arm at all times. The first in the energy storage bridge arm i Port voltage of each submodule The first in the energy storage bridge arm i The equivalent resistance of each submodule The first in the energy storage bridge arm i The equivalent historical voltage source of each submodule R arm The equivalent resistance of the energy storage bridge arm. E arm ( th () is the equivalent historical voltage source of the energy storage bridge arm. N This represents the number of submodules.

8. The method according to any one of claims 1-7, characterized in that, The construction of the interlocking loop based on the operating mode of the individual submodule under the interlocking condition includes: The operating modes of the individual submodule under the locked-out condition are analyzed, and the individual submodule is divided into a half-bridge submodule and an energy storage submodule. Based on the capacitor voltage of the energy storage submodule and the capacitor voltage of the half-bridge submodule, a closed-loop sub-model of the energy storage submodule is constructed. The lockout circuit sub-model of the energy storage sub-module is used as the lockout circuit.

9. A system for constructing an electromagnetic transient simulation model, characterized in that, The system is applicable to high-voltage direct-connected energy storage devices and includes: The energy storage access mode analysis unit is used to analyze the energy storage access mode of the high voltage DC direct-connected energy storage device to determine the topology of a single sub-module in the high voltage DC direct-connected energy storage device, as well as the operating mode of the single sub-module under different operating conditions. The operating conditions include normal operating conditions and locked operating conditions, and the operating modes are used to characterize the internal dynamic characteristics of the individual submodule. An equivalent circuit construction unit is used to construct the equivalent circuit of the high-voltage DC direct-connected energy storage device under normal operating conditions based on the topology of the individual sub-module and the operating mode of the individual sub-module under normal operating conditions. A locking loop construction unit is used to construct a locking loop based on the operating mode of the single submodule under locking conditions; The electromagnetic transient simulation model construction unit is used to construct the electromagnetic transient simulation model of the high-voltage DC direct-connected energy storage device based on the equivalent circuit and the blocking circuit.

10. An electromagnetic transient simulation method, characterized in that, Applicable to high-voltage direct-connected energy storage devices, the method includes: Acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; Based on the switching signal, the equivalent circuit in the electromagnetic transient simulation model is used to simulate the normal operating condition of the high voltage DC direct-connected energy storage device, and the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions is obtained. Based on the switching signal and the blocking signal, the blocking circuit in the electromagnetic transient simulation model is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device, and the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition is obtained. Based on the first simulation results and the second simulation results, the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device are obtained; The electromagnetic transient simulation model is a pre-constructed electromagnetic transient simulation model using the construction method described in any one of claims 1-8, and the electromagnetic transient simulation model is connected to an external DC power supply.

11. An electromagnetic transient simulation system, characterized in that, Applicable to high-voltage direct-connected energy storage devices, the system includes: The signal acquisition unit is used to acquire the switching signal and interlocking signal of the high-voltage DC direct-connected energy storage device; The first simulation unit is used to simulate the normal operating conditions of the high voltage DC direct-connected energy storage device based on the switching signal and using the equivalent circuit in the electromagnetic transient simulation model, so as to obtain the first simulation result of the high voltage DC direct-connected energy storage device under normal operating conditions. The second simulation unit is used to simulate the blocking condition of the high voltage DC direct-connected energy storage device based on the switching signal and the blocking signal, using the blocking circuit in the electromagnetic transient simulation model, and to obtain the second simulation result of the high voltage DC direct-connected energy storage device under the blocking condition. The simulation result determination unit is used to obtain the electromagnetic transient simulation results of the high-voltage DC direct-connected energy storage device based on the first simulation results and the second simulation results; The electromagnetic transient simulation model is an electromagnetic transient simulation model pre-constructed using the construction method described in any one of claims 1-8.

12. A computer device, characterized in that, include: One or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, they implement an electromagnetic transient simulation model construction method as described in any one of claims 1 to 8, or an electromagnetic transient simulation method as described in any one of claims 10.

13. A computer-readable storage medium, characterized in that, It contains a computer program, which, when executed, implements an electromagnetic transient simulation model construction method as described in any one of claims 1 to 8, or an electromagnetic transient simulation method as described in any one of claims 10.

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