Adaptive low voltage ride through control method, controller, system, device and medium

Abstract

The embodiment of the application relates to the field of power system automatic control, and discloses a self-adaptive low-voltage ride-through control method, a controller, a system, equipment and a medium. In the method, the operation state of an SVG is monitored, and the operation state is used to represent the reactive power output state of the SVG; when a power grid fault occurs, a control strategy corresponding to the operation state monitored before the fault occurs is determined as a target control strategy of the SVG according to a pre-set corresponding relationship between the operation state and the control strategy; the corresponding relationship includes N operation states and control strategies corresponding to the N operation states one by one, and N is greater than or equal to 2; and the target control strategy of the SVG is executed. Through the above method, multiple operation scenes of a pure power electronic power system are adapted, voltage support and fault recovery overvoltage suppression are considered, and stable operation of the system is ensured.

Description

Technical Field

[0001] This application relates to the field of power system automation control, and in particular to an adaptive low voltage ride-through control method, controller, system, device and medium. Background Technology

[0002] With the large-scale integration of new energy sources into the power grid, the degree of power electronics in power systems is constantly increasing. Purely electronic power systems, lacking the rotational inertia and high short-circuit capacity provided by synchronous generators, exhibit weak grid characteristics and require Static Var Generators (SVG) to provide rapid reactive power response to cope with system operation fluctuations and faults. Low voltage ride-through is a key function of SVG, used to support voltage and ensure stable operation during system short-circuit faults.

[0003] Most SVG low voltage ride-through control methods employ a single control logic or strategy. When the system load state changes, a single strategy cannot simultaneously meet the dual requirements of voltage support and fault recovery overvoltage suppression, and cannot adapt to the complex operating scenarios of purely electronic power systems, resulting in insufficient applicability. Summary of the Invention

[0004] The purpose of this application is to provide an adaptive low-voltage ride-through control method, controller, system, device and medium, which can adapt to multiple operating scenarios of pure power electronic power systems, take into account voltage support and fault recovery overvoltage suppression, and ensure stable system operation.

[0005] To address the aforementioned technical problems, embodiments of this application provide an adaptive low-voltage ride-through control method for an SVG, comprising: monitoring the operating state of the SVG, wherein the operating state characterizes the reactive power output state of the SVG; when a grid fault occurs, determining the control strategy corresponding to the operating state monitored before the fault occurs as the target control strategy for the SVG according to a pre-set correspondence between operating states and control strategies; wherein the correspondence includes N operating states and control strategies corresponding one-to-one with the N operating states, wherein N is greater than or equal to 2; and executing the target control strategy for the SVG.

[0006] Embodiments of this application also provide an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform an adaptive low-voltage ride-through control method for SVG as described above.

[0007] Embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described adaptive low-voltage ride-through control method for SVG.

[0008] In this embodiment, the method monitors the operating state that characterizes the reactive power output state of the SVG, and establishes a pre-defined correspondence between the operating state and the control strategy. This correspondence includes N operating states and a control strategy corresponding to each of the N operating states. When a grid fault occurs, the method matches and executes the corresponding target control strategy based on the operating state monitored before the fault. This design enables the execution of different control strategies according to the operating state before the fault, solving the problem that a single control strategy cannot adequately cover multiple scenarios and the insufficient adaptability of SVG low-voltage ride-through control in purely power electronic power systems. This, in turn, helps to solve the overvoltage problem during fault recovery in power electronic power systems. Attached Figure Description

[0009] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0010] Figure 1 These are schematic diagrams of an integrated energy system according to some embodiments of this application; Figure 2 This is a logic flowchart of an adaptive low-voltage ride-through control method for SVG according to some embodiments of this application; Figure 3 This is a flowchart of an adaptive low-voltage ride-through control method for an SVG according to some embodiments of this application; Figure 4 This is a flowchart illustrating the SVG runtime state division method and strategy as shown in some embodiments of this application; Figure 5 This is a schematic diagram illustrating the division of operating states based on the upper and lower limits of SVG reactive power according to some embodiments of this application; Figure 6-1 The results are simulations of the single-logic low-voltage ride-through control method for the load substation SVG. Figure 6-2 The results are simulations of the single-logic low-voltage ride-through control method for the SVG of the power station. Figure 7-1 The results are simulations of the adaptive low-voltage ride-through control method for a load station SVG based on some embodiments of this application. Figure 7-2The results are simulations of the adaptive low-voltage ride-through control method for a power station SVG based on some embodiments of this application. Figure 8 This is a schematic diagram of the structure of an SVG controller according to some embodiments of this application; Figure 9 This is a schematic diagram of the structure of an electronic device according to some embodiments of this application. Detailed Implementation

[0011] With the large-scale integration of new energy sources into the power grid, the degree of power electronics in power systems continues to increase, making purely electronic power systems an important direction for future power grid evolution. Purely electronic power systems lack the rotational inertia and high short-circuit capacity provided by synchronous generators, resulting in weak reactive power support and exhibiting overall weak grid characteristics. Therefore, a large number of static varistors (SVGs) are needed to provide rapid reactive power response to cope with power system operational fluctuations and fault conditions. When the load is large, the SVG generates capacitive reactive power to support the system voltage. However, when a short-circuit fault occurs, the SVG enters low-voltage ride-through (LVRT) control mode. Traditional LVRT control methods generate a large amount of reactive power to support the system voltage, which can easily lead to system overvoltage during fault recovery. When the load is small, the SVG generates inductive reactive power or a small amount of capacitive reactive power. When a short-circuit fault occurs, the SVG enters LVRT control mode, and traditional LVRT control strategies are beneficial in suppressing system overvoltage during fault recovery. Therefore, traditional control methods only have a single control logic or strategy, making it difficult to meet the needs of multiple scenarios and adapt to electronic power systems.

[0012] In view of this, some embodiments of this application provide an adaptive low-voltage ride-through control method for SVG, which can be applied to power electronic power systems. In this method, the operating state of the SVG is monitored, and the operating state characterizes the reactive power output state of the SVG. When a grid fault occurs, based on a pre-set correspondence between operating states and control strategies, the control strategy corresponding to the operating state monitored before the fault occurs is determined as the target control strategy for the SVG. The correspondence includes N operating states and control strategies corresponding one-to-one with the N operating states, where N is greater than or equal to 2. The target control strategy for the SVG is then executed. This achieves the requirement of executing different control strategies based on the operating state before the fault, solving the problem that a single strategy cannot adequately cover multiple scenarios, and the insufficient adaptability of SVG low-voltage ride-through control in pure power electronic power systems. This is beneficial for solving the fault recovery overvoltage problem in power electronic power systems.

[0013] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0014] The following describes in detail the implementation details of the adaptive low voltage ride-through control method of the embodiments of this application. The following implementation details are provided for ease of understanding only and are not necessary for implementing this solution.

[0015] The adaptive low-voltage ride-through control method for SVG provided in this application has application scenarios including, but not limited to, power electronic power systems. For example... Figure 1 As shown, Figure 1 This is a schematic diagram of an integrated energy system according to some embodiments of this application. The integrated energy system includes an SVG controller, an SVG, and a power electronic power system. For example... Figure 1 As shown, the left side shows the SVG controller and the SVG. The SVG controller is the core control unit adapted to the pure power electronic system, playing a crucial role in the overall control of the SVG equipment, integration of low-voltage ride-through functionality, and execution of operating condition-based strategies. The AC side of the SVG is connected to the power electronic system through the grid connection point; the SVG controller is electrically connected to the SVG and is used to send command signals to the SVG; the sampling terminal of the SVG controller is connected to the grid connection point to monitor the operating status of the SVG.

[0016] The SVG controller acquires key variables that reflect the operating status of the SVG itself and the system in real time, including the SVG voltage U, reactive power Q, and q-axis current value. These measured values ​​are fed back to the SVG controller, providing data input for monitoring the SVG's operating status and determining its working conditions. The controller processes the collected measurements and outputs a set of commands, such as control commands and current signals, to the SVG device. The SVG receives these commands (e.g., q-axis current reference values). To perform reactive power regulation, and at the connection node between the SVG and the power grid, Figure 1On the right is the power electronic system, which is centered on the power grid and integrates loads, as well as power electronic equipment such as photovoltaics, wind turbines, and energy storage. This type of system has relatively weak grid support capabilities, placing higher demands on the reactive power support and fault response accuracy of the SVG (Static Var Generator). From the overall control and access architecture of the SVG in the power electronic system, the SVG connects to the power electronic system through the grid. The low-voltage ride-through controller controls the normal operation of the SVG based on command values, while simultaneously monitoring the SVG's operating status based on real-time collected Q and U measurements. When a grid fault occurs, the low-voltage ride-through controller, based on the preset correspondence between operating status and control strategy, invokes an appropriate control strategy to allow the SVG to complete low-voltage ride-through, thereby resolving issues such as fault recovery and overvoltage.

[0017] Please see Figure 2 , Figure 2 This is a logic flowchart of adaptive low-voltage ride-through control of an SVG according to some embodiments of this application. Figure 2 This demonstrates the control switching mechanism of the SVG during grid operation: First, it determines whether the SVG voltage (U) is lower than the low voltage ride-through threshold (Uavg). LVRT If the voltage is normal, normal operation control is executed; if the voltage is below the threshold, different operating states are divided according to the reactive power (Q) of the SVG. Each operating state corresponds to a specific low voltage ride-through control strategy (such as strategy 1, strategy N), and the final output is the q-axis current reference value. This enables precise control under different operating scenarios. Furthermore, the low-voltage ride-through controller used in this application needs to acquire the reactive power Q of the SVG (or other variables that can reflect the SVG's operating state, such as the q-axis current value). () is used as the input signal.

[0018] Please see Figure 3 , Figure 3 This is a flowchart of adaptive low-voltage ride-through control of an SVG according to some embodiments of this application. Figure 3 The illustrated process is applied to power electronic power systems. In some embodiments, Figure 3 The process shown may include the following steps.

[0019] Step 310: Monitor the running status of the SVG.

[0020] In step 310, monitoring the operating status of the SVG refers to real-time acquisition of parameters that reflect the reactive power output of the SVG (Static Var Generator) during its operation. These monitored parameters are directly related to the current reactive power output level of the SVG and are used to characterize the reactive power output state of the SVG. By monitoring these related parameters, it can be determined whether the SVG is currently in a state of capacitive reactive power output under high load, inductive reactive power output under low load, or other reactive power output scenarios, providing a basis for subsequent matching of corresponding low voltage ride-through control strategies.

[0021] In some embodiments, the operating state includes one or any combination of the following parameters: voltage reactive power or q-axis current value Due to voltage reactive power or q-axis current value It can accurately and comprehensively capture the operating status of the SVG and the power grid operating environment, directly matching the core functional requirements of the SVG and the technical objectives of low-voltage ride-through control. Therefore, any combination of these three can further improve the accuracy of operating status judgment and the adaptability of control strategies. In this way, it utilizes reactive power... or q-axis current value It captures the reactive power output state of the SVG itself, and then uses voltage... By capturing the voltage environment of the power grid, it ensures that under the weak grid characteristics of a purely electronic power system, the operating status can be accurately identified and the corresponding low-voltage control strategy can be matched regardless of the load size or the type of grid fault. This solves the problem that traditional single strategies are difficult to take into account multiple scenarios and are prone to causing fault recovery overvoltage.

[0022] Step 320: When a power grid fault occurs, the control strategy corresponding to the operating state monitored before the fault occurs is determined as the target control strategy of the SVG based on the pre-set correspondence between the operating state and the control strategy.

[0023] In step 320, when a fault occurs in the power grid, the control strategy corresponding to the operating state monitored before the fault occurs is determined as the target control strategy according to the pre-set correspondence between the operating state and the control strategy. The SVG is divided into N operating states, where N is greater than or equal to 2. Each operating state is bound to a low voltage ride-through control strategy, which is different from the traditional single control logic and thus adapts to the multi-scenario requirements of the pure power electronic power grid.

[0024] The correspondence between the operating states and control strategies in step 320 is not randomly set, but generated through a standardized process. In some embodiments, the correspondence is determined as follows: all allowed operating states of the SVG are clustered to obtain an initial L operating states, where L is greater than or equal to N; for each of the initial L operating states, the corresponding target control strategy is determined through simulation testing; wherein, if multiple operating states correspond to the same target control strategy, the multiple operating states corresponding to the same target control strategy are merged into one.

[0025] Please see Figure 4 , Figure 4 Flowcharts illustrating the SVG runtime state division method and strategy formulation based on some embodiments of this application. For example... Figure 4 As shown, this embodiment formulates different low-voltage ride-through control strategies for SVGs connected to different power stations. First, operational status data of the SVG under different load levels and connection locations are collected to construct a scenario set covering various actual operating scenarios, ensuring that subsequent analysis can cover all possible operating conditions of the SVG. For a specific operating scenario, all allowed operating states of the SVG are clustered. Essentially, based on actual operating data under different load levels and connection locations, operating states with similar characteristics are grouped together, ultimately obtaining an initial set of L operating states, where L is greater than or equal to the final determined N. This step effectively extracts the core operating scenarios of the SVG, avoiding complex and redundant control logic due to overly detailed state division. Next, for each of these L initial operating states, the corresponding target control strategy is determined through simulation testing. Simulation testing can accurately simulate the scenario of short-circuit faults in the power grid under different operating states, verifying and selecting the optimal control strategy that can effectively suppress fault recovery overvoltage and adapt to the characteristics of weak power grids under each state, ensuring the relevance and effectiveness of the strategy. Finally, if multiple initial operating states correspond to the same target control strategy after simulation, it indicates that the reactive power output characteristics and fault response requirements of the SVG are consistent in these states. Merging them into one operating state can simplify the control system, avoid redundant strategy formulation, and ensure control accuracy. Ultimately, a one-to-one correspondence between N operating states and control strategies is formed, which meets the requirements of multi-scenario adaptation and ensures the robustness of the correspondence through standardized processes. This allows for dynamic switching of control strategies during faults and solves the adaptation defects of traditional single strategies.

[0026] In some embodiments, clustering all allowed running states of the SVG to obtain an initial L running states can be achieved as follows: at a preset time interval, obtain the running states of the SVG within a preset time period to obtain M running states, where M is greater than or equal to L; cluster the M running states to obtain the initial L running states.

[0027] Specifically, to achieve dynamic switching of low-voltage ride-through control based on SVG operating status, it is necessary to adapt to multi-scenario control by dividing the operating status. This is achieved through time-dimensional status data acquisition and clustering to ensure that the initial operating status comprehensively and accurately reflects the actual working scenario of the SVG. To capture the dynamic changes in the SVG operating status and avoid the randomness of data at a single point in time, this application acquires the SVG's operating status within a preset time period at preset time intervals. The preset time interval can be collected at minute or hourly intervals to cover dynamic processes such as load fluctuations and transient changes in grid voltage. The preset time period needs to be long enough to encompass various typical operating scenarios that the SVG may face, such as peak, flat, and low load periods within a day, or periods of varying reactive power demand in different seasons, ensuring that the collected status data covers scenarios such as large loads outputting large amounts of capacitive reactive power, or small loads outputting inductive or small amounts of capacitive reactive power. The collected M operating states include the SVG's core status parameters (such as voltage). reactive power or q-axis current value A time-dimensional dataset, such as records taken every hour within a certain time period. , The combination of these data points can fully reflect the reactive power output level of the SVG, the grid voltage environment, and the correlation between the two during the time period. Since there are bound to be multiple sets of similar sequences among the collected M data points (e.g., sequences with the same load level and reactive power output mode in different time periods), subsequent clustering will group these similar sequences into one category.

[0028] The above-described clustering of M operational state data to obtain L initial operational states is a crucial step in extracting core operational states from massive amounts of data. Through this clustering, the originally scattered M data points are summarized into L initial operational states with distinct characteristics. The number L must be sufficient to cover the main operating modes of the SVG, avoiding both overly granular segmentation leading to redundancy in subsequent strategies and overly coarse segmentation that misses key operational states. This provides an operational basis for subsequent simulation testing to determine control strategies for each initial operational state.

[0029] Overall, by collecting time-series data, the comprehensiveness and dynamism of the data are ensured, avoiding the shortcomings of single static data in reflecting the actual operating scenarios. By clustering based on core operating features, massive amounts of data are extracted into a limited number of L initial operating states, providing a data source for subsequent simulation testing to match the corresponding control strategies and finally merge them to obtain the operating states corresponding to N strategies. This solves the problem that traditional single control strategies cannot cover multiple scenarios.

[0030] In some embodiments, for each of the initial L operating states, a corresponding target control strategy is determined through simulation testing. This process includes the following steps: randomly selecting an operating state from the L operating states where no strategy has been determined as the current state; performing simulation testing on the current state to determine a corresponding candidate control strategy; applying the candidate control strategy to the remaining operating states where no strategy has been determined for simulation testing; if the simulation result of a certain operating state among the remaining operating states where no strategy has been determined meets a preset condition under the candidate control strategy, then recording the candidate control strategy as the target control strategy corresponding to that operating state; for operating states where the simulation result under the candidate control strategy does not meet the preset condition, repeatedly selecting and simulating operating states where no strategy has been determined, until all L operating states have a corresponding target control strategy that meets the preset condition.

[0031] In one example, this application randomly selects one of L operating states for which the control strategy has not yet been determined as the current state, and conducts targeted simulation tests. The simulation tests will simulate the actual scenario of a short-circuit fault in the power grid, based on the core characteristic parameters of the current state (such as voltage). reactive power or q-axis current value The execution effects of different control strategies are tested to select strategies that can accurately address the fault response requirements under this state (such as avoiding overvoltage under high load scenarios and maintaining control stability under low load scenarios). These strategies are then identified as candidate control strategies for the current state. Subsequently, this candidate control strategy is applied to other operating states where no matching strategy has been found, and simulation tests are conducted again. The simulation test results must meet the following preset conditions: no short-term overvoltage during fault recovery, appropriate control response speed, and compatibility with the load level and grid environment corresponding to the operating state, meeting the reactive power support requirements of a pure power electronic system. If an operating state where no strategy has been determined meets the preset conditions in the simulation of the candidate control strategy, it indicates that the candidate strategy is compatible with the operating characteristics of that state, and it is recorded as the target control strategy for that state. For operating states where the simulation results do not meet the preset conditions, the above process is repeated. That is, one of the operating states with an undetermined strategy is randomly selected again as the new current operating state. A new candidate control strategy is determined through simulation, and the new candidate strategy is used to verify the remaining unmatched states. This process is repeated until each of the L initial operating states has a target control strategy that meets the preset conditions. This ensures the specificity of each strategy and avoids the inefficiency caused by repeated simulations. Ultimately, each operating state has a corresponding matching strategy, which supports dynamic strategy switching in the event of a subsequent fault.

[0032] In some embodiments, this application further determines the correspondence between operating states and control strategies by: dividing the operating states into N (N≥2) types based on the upper and lower limits of the reactive power of the SVG, or based on the q-axis current value of the SVG. The upper and lower limits are used to divide the operation into N (N≥2) possible states. For example... Figure 5 As shown, and These are the upper and lower limits of SVG reactive power, respectively. and These are the upper and lower limits of the q-axis current of the SVG, respectively. arrive Or from arrive The entire reactive power output range is divided into multiple consecutive sub-intervals, each sub-interval corresponding to an independent SVG operating state (i.e., Figure 5 The SVG is divided into operating states 1, 2, and N. For each independent SVG operating state, the corresponding target control strategy is determined through simulation testing. These control strategies are determined through standardized processes such as simulation testing. Each operating state is matched with a corresponding low-voltage ride-through control strategy, so that the SVG can call the appropriate control strategy under different reactive power output scenarios, avoiding the problem that traditional single strategies cannot cover multiple scenarios.

[0033] In one or more of the above embodiments, the control strategy includes one of the following types: the control strategy corresponding to the Nth operating state is... ,in, For voltage, For reactive power; or, the control strategy corresponding to the Nth operating state is or ,in, This is the q-axis current value. For parameter vectors.

[0034] Specifically, for the first type, "the control strategy corresponding to the Nth operating state is..." “Here” This represents the function corresponding to the nth operating state, where the input variable is the voltage of the SVG at the moment before the fault. reactive power Under different operating conditions, The mathematical structure or computational logic differs. This difference stems from the voltage in different operating states. and reactive power For low voltage ride-through control output (such as low voltage ride-through control output current) The effects of different factors vary: for example, when the SVG is operating under heavy load (outputting a large amount of capacitive reactive power), the voltage... The drop amplitude and reactive power The high output level requires strong response and stable voltage regulation of the control current; however, when operating under low load (output inductive or with a small amount of capacitive reactive power), the voltage... Small fluctuations and reactive power The low output level necessitates minimal intervention and overvoltage protection in the regulation of the control current, and the voltage varies under both scenarios. and reactive power The coupling effects of different operating states are different, so it is necessary to design independent function forms for each operating state to ensure that the function output can accurately match the control requirements of that operating state.

[0035] For the second type, "the control strategy corresponding to the Nth operating state is..." or “Here” It uses a unified basic function structure, and the input is also voltage. and reactive power Or the input is voltage. and q-axis current value Strategy differentiation is achieved through parameter vectors. accomplish. It is an m-dimensional vector containing m tuneable parameters (such as Kn1, Kn2, etc.). Different operating states are achieved by adjusting... The specific values ​​of the parameters allow the unified function to output control quantities adapted to the operating state without altering the function's mathematical structure. For example, the low-voltage ride-through control output current in the nth operating state. , can be represented as , where, in the formula , that is The parameters that can be obtained when given a certain set of parameters. In this way, by obtaining different sets of parameters, the unified function structure can output appropriate control currents under different operating conditions, which simplifies the complexity of function design and ensures that the strategy is applicable to different operating conditions.

[0036] In some embodiments, this application defines the operating state as the q-axis current. and voltage The control strategy corresponding to the Nth operating state is: Thus, the target control strategy for the SVG can be determined in the following ways, including: based on and current threshold Determine the parameter vector in the corresponding control strategy. ;in, greater than the current threshold The operating state is under heavy load, and the parameter vector is... For the first parameter set; Less than or equal to the current threshold The operating state is low load, parameter vector For the second set of parameters; the parameter vector After confirmation This is determined to be the target control strategy for SVG. Among these, the current threshold... The location of the SVG-based station within the power system is determined.

[0037] Specifically, the q-axis current value It can directly characterize the reactive power output characteristics of SVG and can also be used to distinguish the load state of SVG. Voltage U is the core judgment and control variable during the low voltage ride-through process of SVG. When U is lower than the low voltage ride-through threshold U LVRT When this is the case, a control strategy needs to be determined. Therefore, this application sets the operating state to q-axis current. and voltage The corresponding control strategy is set as follows: .this It is a general mathematical function for low voltage ride-through control, and its specific mathematical expression can be described as follows: In the formula , The parameter set is determined by whether the operating state is under heavy load or light load, with the core judgment rule based on the current threshold. As the boundary, the q-axis current value The parameter vector is divided into two intervals, each matching one of two fixed parameter sets. The first or second parameter set is then substituted into the parameter vector. Then, the function becomes a specific, directly executable control strategy tailored to the current operating condition. Furthermore, the current threshold... Instead of fixed, universal values, these values ​​are adjusted based on the attributes of the SVG's location (such as a power station or load station) and its connection point in the power grid. This approach enables personalized adaptation of control strategies to different stations, thus solving the problem that traditional control strategies cannot simultaneously accommodate different stations and load levels.

[0038] In this embodiment, the control strategy is either " "still" "or " Essentially, they all refer to the operating state of the SVG (voltage) before the fault. reactive power or q-axis current value Using the calculated parameters, a differentiated strategy design enables low-voltage ride-through control under each operating state to accurately respond to the demand, ultimately adapting to the weak grid characteristics of pure power electronic systems and solving the problem of fault recovery overvoltage that is easily caused by traditional single strategies.

[0039] Step 330: Execute the target control strategy of the SVG.

[0040] In step 330, the q-axis current value is... Multiply by the first parameter to obtain the first product; then use the voltage Multiply by the second parameter to obtain the second product; sum the first product and the second product to obtain the command signal, and output the command signal to the SVG. The target control strategy is executed through the above calculation process.

[0041] To facilitate understanding, this application provides a specific example of implementing the SVG control strategy. A simulation experiment was conducted in professional power system electromagnetic transient simulation software (Power Systems Computer Aided Design, PSCAD), setting a three-phase non-metallic short-circuit fault on a 220kV line with a fault duration of 150ms.

[0042] Traditional methods use a single control logic, in which... The q-axis current value just before the fault: = ; The method of this application is as follows: As a variable reflecting the running state of SVG, the number of running states is set to N=2. =0.9.

[0043] The control strategy corresponding to the Nth operating state is as follows The control method is as follows: (High load mode); (Low load mode).

[0044] Alternatively, the control strategy corresponding to the Nth operating state can be used. The control method is as follows: (High load mode); (Low load mode).

[0045] The power station parameters are: =0.5, =1.0, =1.0, =-5.0, =-5.0, =0.5; The load station parameters are: =0.0, =0.2, =0.0, =1.0, K22=-0.5, =0.5.

[0046] The simulation results of the two methods mentioned above are as follows: Figure 6-1 , Figure 6-2 , Figure 7-1 and Figure 7-2 As shown. Figure 6-1 and Figure 6-2 This indicates that a short-term overvoltage problem occurred after the fault was cleared, with a voltage peak of 1.70 pu; Figure 7-1 and Figure 7-2 This application demonstrates that it provides voltage support during low-voltage ride-through, eliminating the problem of transient overvoltage after a fault. It also demonstrates that this application effectively solves the short-time overvoltage problem of traditional SVG low-voltage ride-through control methods in purely electronic power systems.

[0047] Because the power grid environment, load characteristics, and fault response requirements of SVGs in different locations are fundamentally different, a uniform correspondence between operating status and control strategy cannot adapt to the personalized scenarios of each site. In view of this, in some embodiments, before step 310, it is necessary to preset corresponding relationships for SVGs in different locations based on the location of the SVG site in the power system (such as a power source side site or a load side site).

[0048] Specifically, the location of SVG (Static Var Generator) power plants within the power system significantly affects their grid support capabilities. Power plants near renewable energy sources like solar and wind turbines experience more pronounced grid weakness due to the lack of inertia support from rotating generators and high short-circuit capacity, resulting in poorer voltage stability and potentially larger voltage drops during faults. Conversely, power plants near load centers experience frequent load fluctuations and more complex dynamic changes in reactive power demand, making grid voltage more significantly affected by load variations. The reactive power support response speed and output capacity requirements for SVG differ across grid locations. Adopting a uniform operating state and control strategy makes it difficult to maintain control accuracy under varying grid conditions. Furthermore, the fault impact range and recovery characteristics of SVGs vary depending on their location. Power plants closer to the fault point experience more severe voltage drops and more complex recovery processes, while those farther from the fault point experience relatively milder voltage fluctuations.

[0049] By pre-setting corresponding relationships based on location, the precision of the operation state division and the adaptability of the strategy parameters can be optimized by combining the fault response patterns of the power station. This allows the SVG to quickly call control strategies that fit the characteristics of the local power grid when a fault occurs, avoiding the adaptation defects caused by traditional single strategies. Ultimately, this ensures that the pure power electronic system can achieve stable low voltage ride-through in different locations and under different operating conditions.

[0050] An adaptive low-voltage ride-through control method for SVG is implemented through one or more of the above embodiments. This method monitors the operating state that characterizes the reactive power output state of the SVG, and presets a correspondence relationship containing N operating states, each of which corresponds to a control strategy. When a grid fault occurs, the target control strategy is determined and executed from the correspondence relationship based on the operating state monitored before the fault occurred. In this way, the requirement to execute different control strategies according to the operating state before the fault is met is realized. This solves the problem that a single strategy is difficult to take into account multiple scenarios, and the problem of insufficient adaptability of SVG low-voltage ride-through control in pure power electronic power systems. It is beneficial to solve the fault recovery overvoltage problem in power electronic power systems.

[0051] The steps described above are for clarity only. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this application. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this patent.

[0052] Furthermore, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The terms "embodiment" or "example" appearing in various locations in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments.

[0053] Another embodiment of this application relates to an SVG controller, such as Figure 8 As shown, the SVG controller includes a storage module, a monitoring module, and an execution module. The storage module stores a pre-defined correspondence between the SVG's operating states and control strategies. This correspondence includes N operating states and a control strategy corresponding to each of the N operating states, where N is greater than or equal to 2. The operating states characterize the reactive power output state of the SVG. The monitoring module monitors the operating states of the SVG. The execution module executes the target control strategy of the SVG, where the target control strategy corresponds to the control strategy monitored before the fault occurred.

[0054] In some embodiments, the SVG controller further includes a strategy module, which is used to preset corresponding relationships for SVGs in different locations based on the location of the SVG in the power system, wherein the location of the SVG in the power system includes a power supply side station or a load side station.

[0055] In some embodiments, the strategy module is further configured to determine the control strategies corresponding to the N operating states. Specifically, it clusters all allowed operating states of the SVG to obtain an initial L operating states, where L is greater than or equal to N. For each of the initial L operating states, a corresponding target control strategy is determined through simulation testing. If multiple operating states correspond to the same target control strategy, the multiple operating states corresponding to the same target control strategy are merged into one. The operating state includes one of the following parameters or any combination thereof: voltage. reactive power or q-axis current value .

[0056] In some embodiments, the strategy module is further configured to randomly select an operating state from L operating states for which no strategy has been determined as the current state, perform simulation testing on the current state, and determine the corresponding candidate control strategy; apply the candidate control strategy to the remaining operating states for which no strategy has been determined for simulation testing; if the simulation result of a certain operating state among the remaining operating states for which no strategy has been determined meets the preset conditions under the candidate control strategy, then record the candidate control strategy as the target control strategy corresponding to that operating state; for operating states for which the simulation result under the candidate control strategy does not meet the preset conditions, repeat the random selection of operating states for which no strategy has been determined and the simulation test, until all L operating states have corresponding target control strategies that meet the preset conditions.

[0057] The control strategy includes one of the following types: the control strategy corresponding to the Nth operating state is... ,in, For voltage, For reactive power; or, the control strategy corresponding to the Nth operating state is or ,in, This is the q-axis current value. For parameter vectors.

[0058] In some embodiments, the strategy module is further configured to obtain the running status of the SVG within a preset time period at preset time intervals, thereby obtaining M running statuses, wherein M is greater than or equal to L; and to cluster the M running statuses to obtain an initial L running statuses.

[0059] In some embodiments, the policy module is further specifically configured to, according to and current threshold Determine the parameter vector in the corresponding control strategy. ;in, greater than the current threshold The operating state is under heavy load, and the parameter vector is... For the first parameter set; Less than or equal to the current threshold The operating state is low load, parameter vector For the second set of parameters; the parameter vector After confirmation This is determined to be the target control strategy for SVG. Among these, the current threshold... The location of the SVG-based station within the power system is determined.

[0060] In some embodiments, the execution module is further specifically used to... Multiply by the first parameter to obtain the first product; Multiply by the second parameter to obtain the second product; sum the first product and the second product to obtain the command signal, and output the command signal to the SVG.

[0061] Another embodiment of this application relates to an electronic device, such as... Figure 9 As shown, the system includes at least one processor and a memory communicatively connected to the at least one processor. The memory stores instructions executable by the at least one processor to enable the at least one processor to perform an adaptive low-voltage ride-through control method for an SVG as described above. The memory and processor are connected via a bus, which may include any number of interconnected buses and bridges, connecting various circuits of one or more processors and the memory. The bus may also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be further described herein. A bus interface provides an interface between the bus and the transceiver. The transceiver may be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over a wireless medium via an antenna, which further receives data and transmits it to the processor. The processor manages the bus and general processing, and may also provide various functions, including timing, peripheral interface, voltage regulation, power management, and other control functions. The memory may be used to store data used by the processor during operation.

[0062] Another embodiment of this application relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method embodiments described above.

[0063] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0064] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. An adaptive low-voltage ride-through control method for SVG, characterized in that, include: Monitor the operating status of the SVG, which is used to characterize the reactive power output status of the SVG; When a power grid fault occurs, the control strategy corresponding to the operating state monitored before the fault occurs is determined as the target control strategy of the SVG according to the pre-set correspondence between the operating state and the control strategy. The correspondence includes N operating states and control strategies corresponding one-to-one with the N operating states, where N is greater than or equal to 2. The target control strategy of the SVG is executed.

2. The adaptive low-voltage ride-through control method for SVG according to claim 1, characterized in that, Prior to monitoring the operational status of the SVG, the method further includes: Based on the location of the SVG in the power system, the corresponding relationship is preset for SVGs in different locations.

3. The adaptive low-voltage ride-through control method for SVG according to claim 2, characterized in that, The location of the SVG in the power system includes power supply side stations or load side stations.

4. The adaptive low-voltage ride-through control method for SVG according to claim 1, characterized in that, The correspondence is determined in the following manner: Cluster all allowed running states of the SVG to obtain an initial L running states, where L is greater than or equal to N; For each of the initial L operating states, the corresponding target control strategy is determined through simulation testing; if multiple operating states correspond to the same target control strategy, the multiple operating states corresponding to the same target control strategy are merged into one.

5. The adaptive low-voltage ride-through control method for SVG according to claim 4, characterized in that, For each of the initial L operating states, the corresponding target control strategy is determined through simulation testing, including: Randomly select an operating state from the L operating states for which no strategy has been determined as the current state, perform simulation tests on the current state, and determine the corresponding candidate control strategy. The candidate control strategies are applied to the operating states of other undetermined strategies for simulation testing; If the simulation result of one of the remaining undetermined operating states under the candidate control strategy meets the preset conditions, then the candidate control strategy is recorded as the target control strategy corresponding to the certain operating state. For operating states where the simulation results under the candidate control strategy do not meet the preset conditions, the simulation test is repeated for randomly selected operating states with undetermined strategies until all L operating states have corresponding target control strategies that meet the preset conditions.

6. The adaptive low-voltage ride-through control method for SVG according to claim 4, characterized in that, The step of clustering all allowed running states of the SVG to obtain an initial L running states includes: The running status of the SVG within a preset time period is obtained at preset time intervals, resulting in M ​​running statuses, wherein M is greater than or equal to L; Clustering the M running states yields the initial L running states.

7. The adaptive low-voltage ride-through control method for SVG according to claim 1, characterized in that, The operating status includes one of the following parameters or any combination thereof: Voltage reactive power or q-axis current value .

8. The adaptive low-voltage ride-through control method for SVG according to claim 1, characterized in that, The control strategy includes one of the following types: The control strategy corresponding to the Nth operating state is: ,in, For voltage, Reactive power; or, The control strategy corresponding to the Nth operating state is: or ,in, This is the q-axis current value. For parameter vectors.

9. The adaptive low-voltage ride-through control method for SVG according to claim 8, characterized in that, The operating status includes the q-axis current. and voltage The control strategy corresponding to the Nth operating state is: ; The step of determining the control strategy corresponding to the operating state monitored before the fault occurred as the target control strategy of the SVG includes: According to the above and current threshold Determine the parameter vector in the corresponding control strategy. ; wherein, the Greater than the current threshold The operating state is a high-load state, and the parameter vector The first parameter set; Less than or equal to the current threshold The operating state is a low-load state, and the parameter vector For the second parameter set; parameter vector After confirmation This is determined as the target control strategy for the SVG.

10. The adaptive low-voltage ride-through control method for SVG according to claim 9, characterized in that, The current threshold The location of the SVG in the power system is determined based on its position.

11. The adaptive low-voltage ride-through control method for SVG according to claim 9, characterized in that, The parameter vector Including the first parameter and the second parameter; The target control strategy for executing the SVG includes: The Multiply by the first parameter to obtain the first product; The Multiplying this by the second parameter yields the second product; The instruction signal is obtained by summing the first product and the second product, and then the instruction signal is output to the SVG.

12. An SVG controller, characterized in that, include: The storage module is used to store the pre-defined correspondence between the operating states and control strategies of the SVG. The correspondence includes N operating states and control strategies that correspond one-to-one with the N operating states. The N is greater than or equal to 2. The operating states are used to characterize the reactive power output state of the SVG. The monitoring module is used to monitor the running status of the SVG; An execution module is used to execute the target control strategy of the SVG, wherein the target control strategy is a control strategy corresponding to the operating state monitored before the fault occurred.

13. An integrated energy system, characterized in that, Includes the SVG controller, SVG, and power electronic power system as described in claim 12; The AC side of the SVG is connected to the power electronic power system through the grid connection point; The SVG controller is electrically connected to the SVG and is used to send command signals to the SVG; The sampling terminal of the SVG controller is connected to the grid connection point to monitor the operating status of the SVG.

14. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the adaptive low-voltage ride-through control method of the SVG as described in any one of claims 1 to 11.

15. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the adaptive low-voltage ride-through control method of the SVG according to any one of claims 1 to 11.

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