A power grid dynamic virtual test evaluation method and system based on digital twinning

Abstract

The application discloses a power grid dynamic virtual test evaluation method based on digital twinning, which is characterized in that a virtual power grid dynamic simulator is connected in series between a power grid signal sensor and a controller of a system to be tested; a host computer transmits power grid dynamic parameters to be simulated to the simulator; the simulator modulates the parameters and actual power grid signals to generate power grid signals containing virtual disturbances and sends the signals to the controller of the system to be tested to disturb the operation of the system; the simulator can also receive control signals of the system to be tested and generate control signals containing disturbances and send the signals to the controller of the system to be tested; meanwhile, the control and output responses under disturbance are collected and analyzed to evaluate the stability, controllability or resilience of the system. The power grid dynamic parameters are generated by a digital twinning model of an actual power grid; the response feedback of the system to be tested is fed back to the digital twinning model to reflect the interactive influence after being connected to the power grid. The application combines digital twinning and virtual simulation to realize safe, efficient and low-cost testing and evaluation of grid-connected equipment under power grid dynamic and fault conditions.

Description

Technical Field

[0001] This invention relates to the field of power system simulation and testing technology, and more specifically, to a method and system for dynamic virtual testing and evaluation of power grids based on digital twins. Background Technology

[0002] As the global energy structure continues its green and low-carbon transformation, the penetration rate of renewable energy sources, such as photovoltaic and wind power, in power systems continues to increase. Most of these energy sources are connected to the grid via inverter-based resources (IBRs), whose dynamic response characteristics differ fundamentally from those of traditional synchronous generators, posing new challenges to the stable operation of power systems. Especially when disturbances such as voltage dips, frequency fluctuations, or phase jumps occur in the grid, the response behavior of IBRs directly affects the safety and stability of the entire system. Therefore, conducting thorough disturbance testing on IBRs before grid connection to verify the effectiveness and robustness of their control strategies has become a crucial step in ensuring the reliable operation of new power systems.

[0003] Currently, there are two main technical approaches to mainstream testing methods. The first is to directly introduce disturbances into the actual operating power grid. While direct, this method carries extremely high risks, potentially triggering real grid faults and causing irreversible damage to power infrastructure. Furthermore, it suffers from limited testing scenarios, poor repeatability, and high costs. The second approach is based on power hardware-in-the-loop (HIL) scaling-up simulation technology. This method constructs a hybrid testing environment using a grid simulator and a scaled-down physical system. While avoiding direct intervention in the actual power grid, it still has significant limitations: the system construction and maintenance costs are high, heavily relying on high-precision power amplifiers and real-time simulators; simulation accuracy and real-time performance are challenged due to limitations in the stability of interface algorithms; and more importantly, it is essentially a scaled-down test, making it difficult to truly reflect the dynamic performance of full-scale power plants under actual grid disturbances, thus casting doubt on the credibility and authority of the test results.

[0004] In recent years, the rise of digital twin technology has provided new ideas for power system simulation. However, most existing digital twin technologies applied in this field still require close integration with traditional hardware-in-the-loop simulation platforms, mainly used for comparative monitoring of equipment or offline analysis of systems. They fail to fundamentally eliminate dependence on complex and expensive external simulation hardware platforms, resulting in limited improvements in testing flexibility, convenience, and cost-effectiveness. Therefore, how to construct a simulation testing solution capable of achieving full-scale, high-fidelity testing while also possessing advantages such as low cost, high efficiency, and high security remains a pressing technical challenge in this field. Summary of the Invention

[0005] In view of the above-mentioned technical problems in related technologies, the present invention proposes a dynamic virtual test and evaluation method and system for power grids based on digital twins, which can overcome the above-mentioned shortcomings of the prior art.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is implemented as follows: A method for dynamic virtual testing and evaluation of power grids based on digital twins; This method for dynamic simulation and testing of a virtual power grid includes the following steps: S1: Connect the power output port of the system under test to the actual power grid or the test power grid; S2: A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test; S3: Input the power grid dynamic parameters to be simulated into the virtual power grid dynamic simulator. The power grid dynamic parameters refer to at least one of the voltage and current amplitude, frequency and phase at the common connection point between the power grid and the system under test, which changes with time. The power grid dynamics include, but are not limited to, single-phase / phase-to-phase / three-phase faults, power oscillations, voltage amplitude drops / rises, frequency changes, phase jumps, etc. S4: The virtual power grid dynamic simulator generates a power grid signal with virtual disturbances through modulation operations based on the received power grid dynamic parameters and the actual power grid signal obtained from the power grid signal sensor. The modulation operations include time-domain operations, frequency-domain operations, or time-frequency domain joint operations based on the actual power grid signal and power grid dynamic parameters. S5: The power grid signal containing the virtual disturbance is transmitted to the controller of the system under test to drive the controller to operate the system according to the disturbance of the signal; S6: Collect the operating response signal of the system under test under the action of the power grid signal or control signal containing virtual disturbance; S7: Based on the operational response signal, evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions.

[0007] Further, in step S1, the system under test is a grid-connected system containing an inverter-based resource (IBR), whose structure includes an inverter, an output filter, a grid signal measurement unit, and a controller.

[0008] Furthermore, in step S3, the dynamic parameters of the power grid to be simulated can be generated by a digital twin model constructed based on the actual power grid; the digital twin model can reflect the interaction between the tested system and the power grid at the point of common coupling after the system is connected.

[0009] Furthermore, in step S5, the power grid signal containing the virtual disturbance is transmitted to the control loop of the controller.

[0010] According to another aspect of the present invention, a power grid dynamic virtual test and evaluation system based on digital twins is provided; The virtual power grid dynamic simulation and testing evaluation system includes: The parameter input module is used to receive the dynamic parameters of the power grid to be simulated. A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test. It has a modulation calculation module inside, which is used to perform modulation calculation on the actual power grid signal based on the power grid dynamic parameters and the power grid signal from the power grid signal sensor, generate a power grid signal with virtual disturbance and output it to the controller. The data acquisition module is used to acquire the operating response signal of the system under test under the action of the power grid signal or control signal containing the virtual disturbance; The performance evaluation module is used to evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions based on the operating response signal.

[0011] Furthermore, the system also includes a digital twin model module of the actual power grid, used to generate the dynamic parameters of the power grid to be simulated based on the actual power grid, and to send them to the parameter input module.

[0012] Furthermore, the digital twin model can reflect the interaction between the tested system and the power grid at the point of common connection after the system is connected.

[0013] Furthermore, the system under test is a grid-connected system based on an inverter-type power supply (IBR), and the controller is a grid-connected inverter controller of the IBR.

[0014] The beneficial effects of this invention are as follows: By designing a virtual power grid dynamic simulator connected in series between the power grid signal measurement unit and the controller of the system under test, and by using digital twin technology and signal modulation methods based on the actual power grid to generate and inject equivalent virtual dynamic signals containing power grid disturbances, it is possible to complete full-scale, high-fidelity excitation and testing of the performance of the system under test under real grid-connected conditions without changing the actual power grid operating state or relying on large-capacity physical power grid emulators. This significantly reduces testing costs and safety risks, significantly improves the flexibility of test scenario construction and the efficiency of the testing process, and achieves a comprehensive and reliable assessment of the power grid adaptability and support capabilities of the equipment under test. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system connection diagram of the digital twin power grid dynamic virtual test and evaluation method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the functional modules of the digital twin power grid dynamic virtual test and evaluation system according to an embodiment of the present invention, and a circuit connection implemented in a laboratory. Figure 3 is an example diagram of signal transmission when the system under test is connected to the power grid according to an embodiment of the present invention, including two parts: the controller of the system under test and the power circuit. in, Figure 3(a) is a block diagram of signal transmission when an inverter-type power supply (IBR) is connected to the power grid, where grid disturbances are injected by the actual power grid. Figure 3(b) is a block diagram of signal transmission when an inverter-type power supply (IBR) is connected to the grid, where grid disturbances are injected by a virtual grid dynamic simulator; Figure 4 is a comparison of simulation results of the constant current operation test of the grid-connected inverter under grid voltage dip conditions according to Embodiment 1 of the present invention. in, Figure 4(a) shows the simulation results of voltage sag disturbances generated by the power grid. Figure 4(b) shows the simulation results of voltage sag disturbance generated by the virtual power grid dynamic simulator. Figure 4(c) is a magnified view of the transient waveform corresponding to the simulation results in Figure 4(a). Figure 4(d) is an enlarged view of the transient waveform corresponding to the simulation results in Figure 4(b); Figure 5 is a waveform diagram of the experimental results of the power grid dynamic virtual test and evaluation method based on digital twin according to an embodiment of the present invention. in, Figure 5(a) shows the transient performance of the inverter current during grid voltage dips. Figure 5(b) shows the transient performance of the inverter current when the grid voltage phase leads. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown in the embodiment of the present invention, a power grid dynamic virtual test and evaluation method based on digital twins includes the following steps: S1: Connect the power output port of the system under test to the actual power grid or the test power grid; S2: A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test; S3: Input the power grid dynamic parameters to be simulated into the virtual power grid dynamic simulator. The power grid dynamic parameters refer to at least one of the voltage and current amplitude, frequency and phase at the common connection point between the power grid and the system under test, which changes with time. The power grid dynamics include, but are not limited to, single-phase / phase-to-phase / three-phase faults, power oscillations, voltage amplitude drops / rises, frequency changes, phase jumps, etc. S4: The virtual power grid dynamic simulator generates a power grid signal with virtual disturbances through modulation operations based on the received power grid dynamic parameters and the actual power grid signal obtained from the power grid signal sensor. The modulation operations include time-domain operations, frequency-domain operations, or time-frequency domain joint operations based on the actual power grid signal and power grid dynamic parameters. S5: The power grid signal containing the virtual disturbance is transmitted to the controller of the system under test to drive the controller to operate the system according to the disturbance of the signal; S6: Collect the operating response signal of the system under test under the action of the power grid signal or control signal containing virtual disturbance; S7: Based on the operational response signal, evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions.

[0019] According to an embodiment of the present invention, a power grid dynamic virtual test and evaluation method based on digital twins is provided. In a specific embodiment, the system under test in step S1 is a grid-connected system containing an inverter-based resource (IBR), and its structure includes an inverter, an output filter, a power grid signal measurement unit, and a controller.

[0020] According to an embodiment of the present invention, a method for dynamic virtual testing and evaluation of power grids based on digital twins is provided. In a specific embodiment, the dynamic parameters of the power grid to be simulated in step S3 can be generated by a digital twin model constructed based on the actual power grid. The digital twin model can reflect the interaction between the tested system and the power grid at the point of common coupling after the system is connected.

[0021] According to an embodiment of the present invention, a power grid dynamic virtual test and evaluation method based on digital twins is provided. In a specific embodiment, in step S5, the power grid signal containing virtual disturbances is transmitted to the control loop of the controller.

[0022] Secondly, such as Figure 2 As shown in the embodiment of the present invention, a power grid dynamic virtual test and evaluation system based on digital twins includes: The parameter input module is used to receive the dynamic parameters of the power grid to be simulated. A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test. It has a modulation calculation module inside, which is used to perform modulation calculation on the power grid dynamic parameters and the actual power grid voltage signal from the power grid signal sensor to generate a power grid signal with virtual disturbance and output it to the controller. The data acquisition module is used to acquire the operating response signals of the system under test under the action of the virtual power grid signal; The performance evaluation module is used to evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions based on the operating response signal.

[0023] According to an embodiment of the present invention, a power grid disturbance virtual simulation test system based on digital twins is provided. In a specific embodiment, the system further includes a digital twin model module of the actual power grid, which is used to generate the dynamic parameters of the power grid to be simulated based on the actual power grid and send them to the parameter input module.

[0024] According to an embodiment of the present invention, a power grid disturbance virtual simulation test system based on digital twins is provided. In a specific embodiment, the digital twin model can reflect the interaction between the tested system and the power grid at the point of common coupling after the system is connected.

[0025] According to an embodiment of the present invention, a grid disturbance virtual simulation test system based on digital twin is provided. In a specific embodiment, the system under test is a grid-connected system based on inverter type power supply (IBR), and the controller is the grid-connected inverter controller of the IBR.

[0026] To facilitate understanding of the above technical solutions of the present invention, the following detailed description of the above technical solutions of the present invention will be provided through specific embodiments and principles.

[0027] System architecture and connection method: The core of the digital twin-based power grid dynamic virtual test and evaluation system provided in this embodiment lies in the deployment of a virtual power grid dynamic simulator. This virtual power grid dynamic simulator is an independent hardware device, and its physical connection in the test system is as follows: it is connected in series between the power grid signal sensor and the controller of the system under test.

[0028] Specifically, such as Figure 1 As shown, the power output port of the device under test is directly connected to the actual power system or a dedicated test grid. The grid signal sensor is used to collect real-time data on the actual operating status at the point of common connection between the grid and the system under test, including the voltage signal V. g and current signal I g The input of the virtual power grid dynamic simulator receives signals from the power grid signal sensor; the output is connected to the controller signal input port of the system under test.

[0029] The system's physical architecture ensures that the system under test operates in a real power grid environment, while the power grid disturbances required for the test are generated by a virtual power grid dynamic simulator through computational modulation to obtain the disturbed voltage signal V. g + ΔV and current signal I g + ΔI, and then sent to the controller of the system under test. On the other hand, the virtual power grid dynamic simulator can also receive the actual control signal C from the controller of the system under test, generate a control signal C + ΔC containing virtual disturbances through modulation calculation, and then send it to the controller of the system under test. The power grid disturbances that the virtual power grid dynamic simulator can generate include, but are not limited to: single-phase / phase-to-phase / three-phase faults, power oscillations, voltage amplitude drops / surges, frequency changes, phase jumps, etc.

[0030] The system's physical architecture ensures that grid-connected equipment can be safely, efficiently, and cost-effectively tested and evaluated under various grid dynamics and fault conditions without altering the actual grid operating conditions or relying on large-capacity power grid emulators.

[0031] Workflow and core principles: The core principle of this system's workflow lies in generating an equivalent power grid disturbance signal through a virtual power grid dynamic simulator and transmitting it to the controller.

[0032] S1. Connect to the power grid and S2. Deploy the simulator: As described in the architecture, connect the power output port of the system under test to the actual power grid or the test power grid; connect the virtual power grid dynamic simulator in series between the power grid and the controller of the grid-connected equipment under test.

[0033] S3. Parameter Input: Using the host computer software, set and send the dynamic parameters of the power grid to be simulated to the virtual power grid dynamic simulator. These parameters define the dynamic processes of the power grid to be simulated, such as single-phase / phase-to-phase / three-phase faults, power oscillations, voltage amplitude drops / surges, frequency changes, phase jumps, etc. This step corresponds to... Figure 2 The function of the parameter input module.

[0034] S4. Signal Generation and Modulation: The modulation calculation module configured inside the virtual power grid dynamic simulator will convert the received power grid dynamic parameter commands into the actual power grid voltage signal V acquired in real time from the power grid signal sensor. g and actual power grid current signal I g Modulation operations are performed. These operations include time-domain operations, frequency-domain operations, or joint time-frequency-domain operations based on the actual power grid signal and dynamic parameters, ultimately generating at least one voltage signal V containing disturbances. g + ΔV or current signal I g + ΔI. This step corresponds to Figure 2 The function of the modulation operation module.

[0035] In a preferred embodiment, the grid dynamic parameters in step S3 are generated by a digital twin model built based on the actual power grid. This digital twin model can simulate the transient, dynamic, and various fault scenarios of complex power system operation, providing the voltage-current characteristics at the grid's point of common coupling and the dynamic process changing over time, thus making the test scenario more realistic and systematic. In particular, when the system under test is an inverter-type power source, such as a photovoltaic power station, wind farm, energy storage power station, or electric vehicle charging station, this digital twin model can reflect the interaction between the system under test and the power grid at the point of common coupling after the system is connected.

[0036] S5. Signal Injection and Control: The virtual power grid dynamic simulator generates virtual power grid disturbance signals and outputs them to the controller of the system under test in real time. Based on these signals, the controller performs control law calculations and generates PWM drive signals to control the operation of power switching devices in the main circuit.

[0037] S6. Data Acquisition: During the test, the data acquisition module synchronously and at high speed acquires the operational response signals of the system under test. These signals typically include the output voltage, current, DC bus voltage of the grid-connected equipment under test, and key controller variables, such as the controller output modulation signal. This step corresponds to... Figure 2 The functions of the data acquisition module.

[0038] S7. Testing and Evaluation: The performance evaluation module analyzes the behavior of the tested system under simulated power grid dynamic conditions based on the operational response signals collected in S6. The core objective of the evaluation is to determine its response capability to power grid disturbances or dynamic conditions. Specifically, this includes a quantitative assessment of its transient and steady-state stability, the controllability of command tracking, and its resilience in returning to normal after the disturbance ends. This step corresponds to... Figure 2 The functionality of the performance evaluation module.

[0039] Furthermore, Figure 3 is a control block diagram of an inverter-type power supply and a schematic diagram of the principle of the power grid dynamic virtual test and evaluation method using digital twins as described in the embodiments of the present invention.

[0040] Figure 3(a) shows the traditional test method and control block diagram of the inverter-type power supply. The signal measurement unit acquires the voltage signal V at the connection point between the system under test and the actual power grid. g and current signal I g The signal is sent to the controller of the system under test. The controller then compares the received measurement signal with the reference command (including the power reference command P). * Q * and voltage and current reference command V * g I * g After comparison and control law calculation, a control signal C is generated and sent to the PWM generator to generate the inverter gate drive pulse. Traditional testing methods require generating voltage disturbances V in the actual power grid or a large-capacity simulated test grid. g +ΔV is applied to the main power circuit of the inverter-type power supply under test, thereby disturbing the system under test (including the controller) and obtaining its response. The transient and steady-state stability, command tracking controllability, and resilience to return to normal after the disturbance are tested and evaluated. Z g Z L These are the grid impedance and grid load, respectively.

[0041] Figure 3(b) is a schematic diagram of the principle of the power grid dynamic virtual test and evaluation method using digital twins as described in this embodiment of the invention. The signal measurement unit collects the voltage signal V at the connection point between the tested system and the actual power grid. g and current signal I g The signal is then fed into a virtual power grid dynamic simulator. This simulator, combining power grid dynamic parameters, generates a power grid voltage signal V containing disturbances through modulation calculations. g + ΔV and current signal I g+ ΔI, and then sent to the controller of the system under test, applied to the original signal input port, transforming the actual power grid disturbance in the traditional method into the signal disturbance within the controller in this embodiment of the invention. On the other hand, the virtual power grid dynamic simulator can receive the control signal C from the controller, combine it with the power grid dynamic parameters, and generate a control signal C + ΔC containing the disturbance through modulation calculation, which is then sent to the controller of the system under test and applied to the original control signal output port. In specific implementation, V can be... g I g The same evaluation and testing effect can be achieved by perturbing any one or two of the signals C, or by perturbing all three signals simultaneously.

[0042] Example 1: Evaluation of low-voltage ride-through test of grid-connected inverter; This embodiment demonstrates in detail, through system simulation, how to apply the present invention's method of using a virtual grid dynamic simulator to generate voltage dip disturbances for low-voltage ride-through testing of a grid-connected inverter. Correspondingly, a grid voltage dip disturbance is generated by the main power circuit, and the output response of the same grid-connected inverter is compared to evaluate the present invention's testing capability for the grid-connected inverter response under grid voltage dip conditions. Figure 4 shows the key waveforms in the testing and evaluation process, from top to bottom representing the inverter output current I... a I b I c Voltage at the point of common coupling of the power grid V a V b V c The controller outputs control signals V for the d-axis and q-axis. d V q And the disturbance signal dV generated by the virtual power grid dynamic simulator d dV q .

[0043] System Configuration: A three-phase grid-connected inverter uses an L-type filter at its AC output terminal to connect to the grid, with a filter impedance of 5%.

[0044] Testing process: Build a system simulation model, including a three-phase grid-connected inverter, filters, controller, and power grid. Set the controller of the grid-connected inverter to constant current mode.

[0045] First, the grid voltage was set to drop by 50% at t = 0.2 seconds and recover after 0.3 seconds. Figure 4(a) shows that the grid-connected inverter can maintain a constant current output in constant current control mode, illustrating the effectiveness of the constant current controller of the tested inverter and its stability under voltage drop disturbance conditions.

[0046] The following uses a virtual power grid dynamic simulator to realize the power grid voltage sag disturbance: at t = 0.2 seconds, a voltage sag disturbance signal dV is generated in the simulator. d and dV q The voltage recovers at t = 0.5 seconds. The grid voltage remains constant throughout the process. As shown in Figure 4(b), the grid-connected inverter maintains a constant current output, demonstrating the effectiveness of the tested inverter's constant current controller and its stability under voltage dip disturbance conditions.

[0047] Figures 4(c) and (d) are enlarged waveforms of the two power grid dynamic disturbance conditions shown in Figures 4(a) and (b), respectively. A comparison reveals that the current response waveforms obtained by the two methods are highly consistent.

[0048] The evaluation module analyzes the current response waveform: checking whether the current exceeds the limit, whether it quickly and accurately tracks the new current reference value, and whether the current smoothly returns to normal after voltage recovery. The results demonstrate that the method of this invention can effectively and equivalently complete the full-power low-voltage ride-through performance evaluation of an inverter system.

[0049] Example 2: Multi-dynamic scenario testing and evaluation in a laboratory environment; This embodiment demonstrates the system's ability to be built in a laboratory environment and to perform various grid dynamic scenario tests on the grid-connected inverter. Figure 5 shows key waveforms during the test and evaluation process, including the grid voltage signal with disturbances generated by the virtual grid dynamic simulator, and the actual output current of the system under test.

[0050] System setup: The device under test: a three-phase digitally controlled grid-connected inverter.

[0051] Virtual power grid dynamic simulator: Implemented using dedicated hardware based on a real-time processor, the signal modulation operation logic of this invention is implemented internally through programming. It can receive power grid dynamic parameters generated by the power grid digital twin model as needed, and simultaneously feed back the response of the tested system to the power grid digital twin model, which is used to evaluate the interaction between the tested system and the power grid at the point of common coupling after the system is connected.

[0052] Connection: Connect strictly according to the aforementioned architecture, connect the grid sensor signal to the simulator, and then connect the simulator output to the signal sampling port of the inverter controller.

[0053] Test scenarios and processes: Two typical tests are performed: Scenario A: Symmetrical voltage drop test of the power grid.

[0054] Scenario B: Grid voltage phase jump test: Simulates grid voltage phase instantaneously leading by 30 degrees.

[0055] General testing process: After system initialization, the virtual grid dynamic simulator is initially in direct mode, outputting a virtual grid voltage signal equal to the actual grid voltage signal, and the inverter operates smoothly.

[0056] The host computer selects and starts the test scenario. The host computer then sends the dynamic parameters of the corresponding scenario to the simulator.

[0057] The signal modulation module inside the simulator performs amplitude or phase modulation calculations on the actual grid voltage signal in real time based on the received dynamic parameters, and generates and outputs a virtual grid voltage signal containing preset disturbances to the inverter controller.

[0058] The inverter controller receives voltage amplitude or phase disturbances generated by the simulator, and its control algorithm responds to the disturbance conditions by adjusting the control output.

[0059] The data acquisition module synchronously records waveforms such as virtual grid voltage signals and inverter output current.

[0060] Experimental Results and Analysis: For scenario A, voltage dip: Figure 5(a) shows the waveform of a 20% voltage dip in the virtual grid generated by the virtual grid dynamic simulator, and the corresponding actual current output waveform of the tested system. The experimental waveforms show that the inverter output current increases rapidly after the voltage dip to provide power support, and there is no oscillation during the transient process.

[0061] For scenario B, phase jump: Figure 5(b) shows the waveform of a 30° phase jump (lead) in the virtual grid voltage generated by the virtual grid dynamic simulator, and the corresponding actual current output waveform of the tested system. The experimental waveform shows that after the "phase jump" occurs, the inverter output current undergoes a brief synchronous transient process, and its current control loop quickly and smoothly relocks the new phase, and the current rapidly returns to synchronous operation.

[0062] Evaluation Conclusion: The test results show that the power grid dynamic virtual test and evaluation method and system based on digital twins provided by this invention can reproduce various power grid dynamic operating conditions in a low-cost, safe, reliable and flexible manner. Based on the real response of the tested system in a full-power operating environment connected to the actual power grid, it can comprehensively evaluate the stability, controllability and resilience of the tested system under different types of power grid disturbances.

[0063] In summary, by utilizing the above-mentioned technical solution of this invention, a virtual power grid dynamic simulator is designed to be connected in series between power grid sensors and equipment controllers. Using digital twin technology and signal modulation methods based on actual power grid models, equivalent power grid dynamic signals are generated and injected on the digital side. This allows for full-scale, high-fidelity excitation and testing of the control performance of the system under test under real grid-connected conditions without altering the actual power grid operating state or relying on large-capacity physical simulation equipment. This significantly reduces testing costs and safety risks, greatly improves the flexibility of test scenario construction and the efficiency of the testing process, and achieves a comprehensive and reliable assessment of the power grid adaptability and support capabilities of the equipment under test.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for dynamic virtual testing and evaluation of power grids based on digital twins, characterized in that, Includes the following steps: S1: Connect the power output port of the system under test to the actual power grid or the test power grid; In step S1, the system under test is a grid-connected system containing an inverter-type power supply IBR, and its structure includes an inverter, an output filter, a grid signal measurement unit, and a controller. S2: A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test; S3: Input the power grid dynamic parameters to be simulated into the virtual power grid dynamic simulator, wherein the power grid dynamic parameters refer to at least one of the voltage and current amplitude, frequency and phase at the common connection point between the power grid and the system under test, which changes with time; wherein the power grid dynamics include single-phase / phase-to-phase / three-phase faults, power oscillations, voltage amplitude drops / rises, frequency changes and phase jumps. In step S3, the dynamic parameters of the power grid to be simulated can be generated by a digital twin model built based on the actual power grid; the digital twin model can reflect the interaction between the tested system and the power grid at the point of common coupling after the system is connected. S4: The virtual power grid dynamic simulator generates a power grid signal with virtual disturbances through modulation operations based on the received power grid dynamic parameters and the actual power grid signal obtained from the power grid signal sensor. The modulation operations include time-domain operations, frequency-domain operations, or time-frequency domain joint operations based on the actual power grid signal and power grid dynamic parameters. S5: The power grid signal containing virtual disturbance is transmitted to the controller of the system under test to drive the controller to operate the system according to the power grid signal containing virtual disturbance; S6: Collect the operating response signal of the system under test under the action of the power grid signal or control signal containing virtual disturbance; S7: Based on the operational response signal, evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions.

2. The method for dynamic virtual testing and evaluation of power grids based on digital twins according to claim 1, characterized in that, In step S5, the power grid signal containing virtual disturbances is transmitted to the control loop of the controller.

3. A power grid dynamic virtual test and evaluation system based on digital twins, used to implement the method according to any one of claims 1-2, characterized in that, include: The parameter input module is used to receive the dynamic parameters of the power grid to be simulated; A virtual power grid dynamic simulator is connected in series between the power grid signal sensor and the controller of the system under test. It has a modulation calculation module inside, which is used to perform modulation calculation on the actual power grid signal based on the power grid dynamic parameters and the power grid signal from the power grid signal sensor, generate a power grid signal with virtual disturbance and output it to the controller. The data acquisition module is used to acquire the operating response signal of the system under test under the action of the power grid signal or control signal containing the virtual disturbance; The performance evaluation module is used to evaluate the response capability of the tested system to power grid disturbances or dynamic operating conditions based on the operating response signal. The system also includes a digital twin model module of the actual power grid, which is used to generate dynamic parameters of the power grid to be simulated based on the actual power grid and send them to the parameter input module; The digital twin model can reflect the interaction between the tested system and the power grid at the point of common coupling after the system is connected; The system under test is a grid-connected system based on an inverter-type power supply (IBR), and the controller is the grid-connected inverter controller of the IBR.

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