Constant voltage control method and device for SVG (static var generator) of power grid

Abstract

The invention discloses a constant voltage control method and device for a power grid SVG, and relates to the technical field of constant voltage control, and the method comprises the steps: determining a voltage dynamic graph based on a multiple closed-loop control region, a plurality of voltage parameters and the working state of the power grid SVG; the corresponding voltage fluctuation range is determined based on the identification of the voltage dynamic graph, and the corresponding constant voltage control system is determined according to the voltage fluctuation range, the load condition of the power grid topology model and the working state of the power grid SVG, so that the accuracy of the constant voltage control body is improved. Therefore, a circuit control area is determined based on the constant voltage control event, the distribution diagram of the power grid topology model and the power grid SVG, a steady-state event of the circuit control area is determined according to amplitude limiting control of the circuit control area, and a corresponding voltage steady-state system is constructed based on the steady-state event of the circuit control area, the voltage dynamic diagram and the working state of the power grid SVG. And the accuracy of the voltage steady-state system is improved.

Description

Technical Field

[0001] This invention relates to the technical field of constant voltage control, and more particularly to a constant voltage control method and apparatus for a power grid SVG. Background Technology

[0002] With the development of technology, SVG (Static Var Generator) is increasingly being applied in the power grid field. SVG is a core power electronic device in modern Flexible AC Transmission Systems (FACTS) and smart distribution networks. Current technology marks the current position of the SVG, determines its steady-state mode based on multiple operating parameters, and performs corresponding closed-loop control along a single steady-state control path. However, this ignores voltage fluctuation range and the load conditions of the power grid topology model, affecting the accuracy of the constant voltage control and resulting in low accuracy of the voltage steady-state system. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a constant voltage control method and device for a power grid SVG.

[0004] This invention provides a constant voltage control method for a power grid SVG, comprising: A corresponding power grid topology model is constructed based on the parallel connection of the low-voltage busbars of the power grid SVG and distribution transformers. The power grid topology path is determined based on the identification of the power grid topology model, and multiple power grid topology nodes are marked. The multi-loop control region is determined based on the node location, corresponding voltage parameters, and harmonic control commands of each power grid topology node. The voltage dynamic diagram is determined based on the multi-loop control region, multiple voltage parameters, and the working state of the power grid SVG. The voltage dynamic diagram presents a voltage distribution cloud map, a sensitivity heat map, and a disturbance trajectory prediction. Based on the identification of the voltage dynamic diagram, the corresponding voltage fluctuation range is determined, and the corresponding constant voltage control system is determined according to the voltage fluctuation range, the load condition of the power grid topology model and the working state of the power grid SVG. In the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined according to the control content of the multiple constant voltage control measures, their corresponding control priorities, and the real-time power of the power grid topology model. The constant voltage control event includes the target device, control mode, specific reference value, and power limit. Based on constant voltage control events, the distribution map of the power grid topology model, and the power grid SVG, the circuit control area is determined. The steady-state events of the circuit control area are determined according to the amplitude limiting control of the circuit control area. Based on the steady-state events of the circuit control area, the voltage dynamic diagram, and the working state of the power grid SVG, the corresponding voltage steady-state system is constructed. The amplitude limiting control content presents the graded intervention measures that should be taken when the system approaches or touches the safety boundary.

[0005] This invention provides a constant voltage control device for a power grid SVG, which is applied to the aforementioned constant voltage control method for a power grid SVG.

[0006] Compared with the prior art, the beneficial effects of the present invention are: In this embodiment of the invention, a corresponding power grid topology model is constructed based on the parallel connection of the low-voltage busbars of the power grid SVG and the distribution transformer. The power grid topology path is determined based on the identification of this topology model, and multiple power grid topology nodes are marked. Multiple closed-loop control regions are determined based on the node positions of each power grid topology node, corresponding voltage parameters, and harmonic control commands. A voltage dynamic diagram is determined based on this multiple closed-loop control region, multiple voltage parameters, and the operating state of the power grid SVG. The corresponding voltage fluctuation range is determined based on the identification of this voltage dynamic diagram. A corresponding constant voltage control system is determined based on this voltage fluctuation range, the load condition of the power grid topology model, and the operating state of the power grid SVG. The introduction of multiple closed-loop control regions further controls the voltage dynamic diagram, accommodating the voltage fluctuation range, the load condition of the power grid topology model, and the operating state of the power grid SVG, thus improving the accuracy of the constant voltage control system.

[0007] Therefore, in the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined according to the control content, corresponding control priority, and real-time power of the power grid topology model of the multiple constant voltage control measures. The circuit control area is determined based on the constant voltage control event, the distribution map of the power grid topology model, and the power grid SVG. The steady-state event of the circuit control area is determined according to the amplitude limiting control of the circuit control area. The corresponding voltage steady-state system is constructed based on the steady-state event of the circuit control area, the voltage dynamic diagram, and the working state of the power grid SVG. The constant voltage control event is introduced to control the steady-state event of the circuit control area, realizing the overall consideration of the steady-state event, voltage dynamic diagram, and working state of the power grid SVG in the circuit control area, thus improving the accuracy of the voltage steady-state system. Attached Figure Description

[0008] Figure 1 This is a flowchart illustrating the constant voltage control method for the power grid SVG in an embodiment of the present invention. Figure 2 This is a flowchart illustrating step S11 in the constant voltage control method for the power grid SVG in this embodiment of the invention. Figure 3 This is a flowchart illustrating step S12 in the constant voltage control method for the power grid SVG in this embodiment of the invention. Figure 4 This is a flowchart illustrating step S13 in the constant voltage control method for the power grid SVG in this embodiment of the invention. Figure 5 This is a flowchart illustrating step S14 in the constant voltage control method for the power grid SVG in this embodiment of the invention. Figure 6 This is a flowchart illustrating step S15 in the constant voltage control method for the power grid SVG in this embodiment of the invention. Figure 7 This is a schematic diagram of the structure of the constant voltage control device for the power grid SVG in an embodiment of the present invention. Detailed Implementation

[0009] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0010] In existing technologies, the current position of the power grid SVG is marked, the steady-state mode of the power grid SVG is determined based on multiple operating parameters of the power grid SVG, and corresponding closed-loop control is performed along a single steady-state control content. However, the voltage fluctuation range and the load conditions of the power grid topology model are ignored, which affects the accuracy of the constant voltage control body and results in low accuracy of the voltage steady-state system. Furthermore, conventional SVG control mainly focuses on the power factor compensation function to avoid power regulation charges, and fails to be applied to situations where voltage fluctuations caused by external or local load fluctuations affect the normal operation of equipment in the local load segment.

[0011] Please see Figures 1 to 7 A constant voltage control method for a power grid SVG, applied to constant voltage control scenarios; the constant voltage control method for a power grid SVG includes: Step S11: Construct a corresponding power grid topology model based on the parallel connection of the low-voltage busbars of the power grid SVG and distribution transformers, determine the power grid topology path based on the identification of the power grid topology model, and mark multiple power grid topology nodes; Step S12: Determine the multi-loop control region based on the node location, corresponding voltage parameters, and harmonic control commands of each power grid topology node; and determine the voltage dynamic diagram based on the multi-loop control region, multiple voltage parameters, and the working state of the power grid SVG. Step S13: Based on the identification of the voltage dynamic diagram, determine the corresponding voltage fluctuation range, and determine the corresponding constant voltage control system according to the voltage fluctuation range, the load condition of the power grid topology model and the working state of the power grid SVG; Step S14: In the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined according to the control content of the multiple constant voltage control measures, the corresponding control priority, and the real-time power of the power grid topology model. Step S15: Based on the constant voltage control events, the distribution map of the power grid topology model, and the power grid SVG, determine the circuit control region. Based on the limiting control of this circuit control region, determine the steady-state events of the circuit control region. Based on the steady-state events of this circuit control region, the voltage dynamic diagram, and the operating state of the power grid SVG, construct the corresponding voltage steady-state system. (Reference) Figure 2 In step S11, the specific steps are as follows: S111: Collect the current location of the power grid SVG and mark the distribution map of the low-voltage busbar of the distribution transformer. Based on the distribution map of the low-voltage busbar of the distribution transformer, the current location of the power grid SVG and the function of the power grid SVG, construct the corresponding parallel system. Based on the parallel system, the distribution transformer and the power grid SVG, construct the corresponding power grid topology model. S112: Identify the power grid topology model and output multiple sub-power grid topology regions. Determine the power grid topology path based on the regional location and corresponding influence range of the multiple sub-power grid topology regions. Determine multiple power grid topology nodes based on the detection of the power grid topology path.

[0012] In the embodiments of this application, the current location of the power grid SVG is collected, and the distribution map of the low-voltage busbar of the distribution transformer is marked. Based on the distribution map of the low-voltage busbar of the distribution transformer, the current location of the power grid SVG, and the function of the power grid SVG, a corresponding parallel system is constructed. Based on this parallel system, the distribution transformer, and the power grid SVG, a corresponding power grid topology model is constructed, which is compatible with the overall consideration of the distribution map of the low-voltage busbar of the distribution transformer, the current location of the power grid SVG, and the function of the power grid SVG, thus ensuring the accuracy of the corresponding parallel system.

[0013] At this point, the precise acquisition of the specific location of the SVG device in the electrical network—specifically, its access point in the topology, rather than its geographical coordinates—is the starting point for all control logic. After obtaining the location information, the system needs to mark the bus distribution on the low-voltage side of the distribution transformer. This step essentially abstracts the physical power grid into an electrical single-line diagram containing all key nodes and connections, which is a crucial step in building a digital twin model.

[0014] Based on this, the system will construct a clear parallel system, treating the SVG as a controllable reactive power generator, forming a parallel compensation system with the low-voltage bus. Its control port is the grid connection point, and its output characteristics are defined as a dynamic reactive current source that can operate in four quadrants. The system integrates all component models, electrical parameters, and connection relationships of the power supply, network, load, and SVG parallel system to form a complete power grid topology model that can be used for power flow calculation and dynamic analysis. Specifically, the system engineer explicitly sets the access point of the SVG in the configuration file as: Power Grid_No.1 Main Transformer_Low-voltage Busbar_Incoming Line Cabinet_Busbar. The system reads this configuration during initialization to confirm that the SVG is directly connected in parallel to the 400V low-voltage busbar of the No.1 main transformer, and its regulation will directly affect all loads carried by the busbar.

[0015] The electrical single-line diagram of the low-voltage side was exported from the power grid's distribution monitoring system and digitally modeled. The model clearly shows that four main feeders branch off from the low-voltage bus of the No. 1 main transformer, which respectively connect to the precision instrument workshop as a sensitive load, the large motor starting area with impact load, the conventional office lighting, and the photovoltaic power generation system as an intermittent power source.

[0016] In the above digital model, we add a component called Grid_SVG_1 to the node of No. 1 main transformer_low voltage bus. This component is set as a controllable voltage source inverter, whose core function is dynamic reactive power compensation. The control port is locked to the voltage of this node, and the output capacity is calibrated to ±200kvar. In this way, a parallel compensation system model of SVG-bus is established.

[0017] All elements are integrated into a complete low-voltage power grid topology model. This model includes a No. 1 main transformer power supply with a capacity of 1250kVA and a short-circuit impedance of 6%, four feeder networks with specific line impedances, and four load models with different characteristics. The power grid _SVG_1 connected in parallel to the bus is also incorporated as a control unit. Thus, a high-fidelity digital twin model of the low-voltage power grid that can be used for simulation analysis is completed.

[0018] Furthermore, the power grid topology model is identified, and multiple sub-power grid topology regions are output. The power grid topology path is determined based on the regional location and corresponding influence range of the multiple sub-power grid topology regions. Multiple power grid topology nodes are determined based on the detection of the power grid topology path, which takes into account the overall consideration of the regional location and corresponding influence range of the multiple sub-power grid topology regions, ensuring the accuracy of the power grid topology path.

[0019] At this point, the system will identify the entire power grid topology model and logically divide it into multiple smaller, more manageable sub-grid topology regions based on principles such as electrical distance, load characteristics, power supply level, or network structure. Subsequently, the system will determine the power grid topology path from the SVG grid connection point to each region and between regions based on the location and interrelationship of these sub-regions. It will trace the electrical path through graph theory algorithms and quantify the path impedance and voltage-reactive power sensitivity to clarify the impact range of SVG actions and the electrical coupling degree between different regions.

[0020] Based on these analyzed topology paths, the system will accurately identify multiple key power grid topology nodes. These nodes include assessment points that serve as control objectives, monitoring points used for state evaluation, characteristic points representing typical operation, and decoupling points that provide isolation. Together, they constitute the execution terminal of the control system.

[0021] Specifically, the control system performs automatic analysis based on the park's model, and divides the entire network into four sub-regions according to load characteristics and control requirements: Z1 (precision instrument zone), due to its high power quality requirements; Z2 (motor impact zone), due to the impact of its load; Z3 (normal load zone), due to its stable load and low priority; and Z4 (new energy access zone), due to its intermittent power supply.

[0022] The system then analyzes the electrical paths from the SVG grid connection point (No. 1 main transformer_low voltage bus) to each sub-region. For example, the path to Z1 is accurately traced, and its transfer impedance and voltage-reactive power sensitivity are calculated, indicating that the SVG has a strong control capability over this region. At the same time, the system evaluates the coupling between regions and finds that Z1 and Z2 have a strong coupling relationship because they are both directly connected to the main bus, which means that the control of Z2 must take into account its potential impact on Z1.

[0023] Based on the above path analysis, the system marks key nodes on the model. Among them, assessment point N1 is set at the inlet of the precision instrument workshop as the primary target for voltage stability; assessment point N2 is located at the terminal of the large motor to monitor the voltage drop during startup; monitoring point M1 is set as the grid connection point of the SVG as the core feedback point; monitoring point M2 is set at the grid connection point of the photovoltaic feeder F4 to monitor the injection of new energy; in addition, a characteristic point C1 representing the conventional load is also set.

[0024] Meanwhile, a corresponding power grid topology model is constructed based on the parallel connection of the low-voltage busbars of the power grid SVG and distribution transformer. By adopting the parallel connection method, when the voltage at the parallel connection point is low, the voltage is raised to the qualified range for load operation, and when the voltage at the parallel connection point is high, the voltage is lowered to the qualified range for load operation, so as to avoid overvoltage damage or undervoltage protection of the load and ensure the normal operation of the load.

[0025] At this point, based on the parallel topology model of the power grid SVG and the low-voltage busbar of the distribution transformer, the core mechanism is to utilize the SVG as a high-speed, dynamically adjustable reactive power source to achieve precise bidirectional stable control of the voltage at the connection point. Specifically, the system intelligently judges the reactive power demand of the power grid by monitoring the voltage level at the parallel installation point in real time: when it detects that the voltage is below the acceptable range due to excessive inductive reactive power absorption by the load, the SVG converter will respond quickly, injecting an equal amount of capacitive reactive power into the power grid. This is equivalent to providing a dynamic capacitor support on the line, effectively offsetting the voltage drop caused by the inductive load, thereby raising the voltage to the level required for normal load operation; if necessary, in order to increase the voltage, the SVG converter injects excessive capacitive reactive power, causing the busbar at the installation point to exhibit... In this capacitive topology, the transformer (L) and line (C) form an LC circuit. Utilizing the principle that the inductive electromotive force and capacitor voltage are opposite and their voltage amplitudes are superimposed, the voltage at the installation point is further increased. Conversely, when the system is under light load or the voltage is too high due to other factors, the SVG switches its operating mode, absorbing inductive reactive power from the grid. This is equivalent to providing a dynamic inductance to balance the excess capacitive reactive power in the system, thereby suppressing excessive voltage rise. Through this continuous and rapid reactive power compensation process of raising the voltage during undervoltage and lowering it during overvoltage, this topology model can always clamp the voltage at the parallel installation points within a preset acceptable range, thus completely avoiding overvoltage damage or undervoltage protection activation caused by voltage fluctuations, ensuring the safe, stable, and efficient operation of various sensitive loads and critical equipment.

[0026] refer to Figure 3 In step S12, the specific steps are as follows: S121: Among multiple power grid topology nodes, the node position of the power grid topology node is determined based on the identification of each power grid topology node, and the corresponding voltage parameters are determined based on the detection of each power grid topology node. At the same time, harmonic control commands are collected, and the first control part is determined based on the node position of each power grid topology node and the harmonic control commands. S122: The second control section is determined based on the voltage parameters and harmonic control commands of each grid topology node, and the multi-loop control region is determined based on the first and second control sections; at the same time, the working state of the grid SVG is determined based on the identification of the working signal of the grid SVG, and the voltage dynamic diagram is determined based on the multi-loop control region, multiple voltage parameters and the working state of the grid SVG.

[0027] In the embodiments of this application, among multiple power grid topology nodes, the node position of each power grid topology node is determined based on the identification of each power grid topology node, and the corresponding voltage parameters are determined based on the detection of each power grid topology node. At the same time, harmonic control commands are collected, and the first control part is determined based on the node position of each power grid topology node and the harmonic control commands. This approach takes into account the overall consideration of the node position of each power grid topology node and the harmonic control commands, ensuring the accuracy of the first control part.

[0028] At this point, by accurately mapping each power grid topology node to devices and sensors in the physical world, the specific node location and communication address are determined. The system will collect and process electrical data from these located nodes in real time, extracting key voltage parameters including fundamental voltage amplitude and phase angle, harmonic distortion rate (THD), and sequence components. At the same time, the system will collect harmonic control commands from the upper-level system or local presets to clarify the specific objectives of power quality management.

[0029] The system combines the needs of harmonic regulation with the physical layout of the power grid. By matching target nodes, identifying key harmonic sources and their impact paths, it delineates a logical control area with harmonic control as its core, namely the first level of control.

[0030] Specifically, the system queries the topology database to map abstract nodes to physical devices one by one; for example, it confirms that assessment point N1 is located in the main incoming line cabinet of the precision instrument workshop, and its data is provided by the smart meter with the address 10.1.1.5; SVG grid connection point M1 is located in the SVG switch cabinet in the low-voltage room of the No. 1 main transformer, and the controller address is 10.1.1.2.

[0031] The system then collected data from the above addresses in real time at a high sampling rate; the data collected from point N1 showed that its fundamental voltage was 399.2V, but the THD was as high as 8.5%, with the 5th and 7th harmonics being particularly prominent; while the data collected from the SVG grid connection point M1 showed that its current output reactive power was +15kvar.

[0032] At this point, the system receives a clear control instruction from the upper-level EMS, requiring the THD at point N1 to be suppressed to below 4%, with a focus on suppressing the 5th and 7th harmonics. After parsing the instruction, the system uses point N1 as the target and, through harmonic power flow analysis, identifies that the main harmonic source comes from the frequency converter in the Z1 area. Therefore, the system designates the assessment points N1, the Z1 feeder branch, and the frequency converter load nodes on them as the first control section. The first control section clarifies that the current core task is to perform fine harmonic compensation in the corresponding area.

[0033] Furthermore, a second control section is determined based on the voltage parameters and harmonic control commands of each grid topology node, and a multi-loop control region is determined based on the first and second control sections. At the same time, the operating state of the grid SVG is determined based on the identification of the grid SVG's operating signal, and a voltage dynamic diagram is determined based on the multi-loop control region, multiple voltage parameters, and the operating state of the grid SVG. This approach takes into account the overall consideration of the multi-loop control region, multiple voltage parameters, and the operating state of the grid SVG, ensuring the accuracy of the voltage dynamic diagram.

[0034] At this point, the system will identify key nodes with voltage over-limit risk or severe fluctuations based on the real-time voltage parameters of each node, and define them and their associated paths as the second control part with the goal of stabilizing the fundamental voltage. The second control part presents the key nodes with voltage over-limit risk or severe fluctuations and their corresponding associated paths. The system will perform superposition and coupling analysis on this second control part and the first control part (harmonic mitigation zone) defined in S121. Based on the overlap between them, a multi-loop control region will be formed, which contains closed-loop control strategies with single or multiple objectives.

[0035] While constructing the control framework, the system must identify the operating status of the SVG in real time. By reading its status register and key operating parameters, the system can assess its available reactive power capacity, health status, and capability boundaries. The system integrates the targets of multiple closed-loop control areas, the real-time voltage parameters of the entire network, and the real-time operating status of the SVG to generate a voltage dynamic map. This voltage dynamic map presents a voltage distribution cloud map, a sensitivity heat map, and a disturbance trajectory prediction, providing comprehensive and forward-looking information support for the final control decision.

[0036] Specifically, the system detected that although the voltage at point N2 (motor zone) was within the acceptable range, a large motor was about to start according to the PLC signal and load prediction. Calculations showed that the voltage at point N2 would drop below the lower limit during startup. Therefore, the system identified the assessment point N2 and its corresponding Z2 area as the second level of control, with the goal of providing rapid reactive power support during motor startup to ensure voltage stability.

[0037] System analysis revealed that Z1 (harmonic mitigation zone) and Z2 (voltage support zone) are controlled by the same SVG and are electrically coupled. Therefore, the system defines Z1 as a multi-loop control region A using a voltage-harmonic coordinated control strategy, and Z2 as a multi-loop control region B using a fast voltage support strategy, with the two working together.

[0038] The system queries the SVG controller in real time to confirm that it is in normal operation, the DC bus voltage is stable, the temperature is normal, and there is still a usable reactive power capacity of ±180kvar, which is fully capable of performing harmonic mitigation and dynamic voltage support tasks simultaneously. The system integrates all information to generate a real-time voltage dynamic graph. This graph not only shows the current voltage and harmonic status of points N1 and N2, but also clearly indicates their respective control targets. More importantly, the graph includes a predicted trajectory, vividly demonstrating that if the SVG quickly outputs +120kvar reactive power when the motor starts, the voltage at point N2 can be successfully supported above the target value, while this operation does not have a negative impact on the harmonic compensation effect at point N1.

[0039] refer to Figure 4 In step S13, the specific steps are as follows: S131: Based on the detection of the voltage dynamic diagram, multiple voltage fluctuation regions are determined. Based on the regional location of each voltage fluctuation region, the corresponding regional location, and the corresponding fluctuation peak, multiple sub-voltage fluctuation ranges are determined. Based on the matching of multiple sub-voltage fluctuation ranges, the corresponding voltage fluctuation range is determined. S132: Collect multiple load parameters of the power grid topology model, determine the load condition of the power grid topology model based on the identification of multiple load parameters, and determine the first level of constant voltage control content based on the voltage fluctuation range and the load condition of the power grid topology model. S133: Obtain the operating status of the power grid SVG, determine the second level of constant voltage control content based on the voltage fluctuation range and the operating status of the power grid SVG, and determine the corresponding constant voltage control system based on the first level of constant voltage control content and the second level of constant voltage control content.

[0040] In the embodiments of this application, multiple voltage fluctuation regions are determined based on the detection of the voltage dynamic map, and multiple sub-voltage fluctuation ranges are determined according to the regional location of each voltage fluctuation region, the corresponding regional location, and the corresponding fluctuation peak. The corresponding voltage fluctuation range is determined based on the matching of multiple sub-voltage fluctuation ranges, which takes into account the overall consideration of matching multiple sub-voltage fluctuation ranges and ensures the accuracy of the corresponding voltage fluctuation range.

[0041] At this point, based on the voltage dynamic map generated by S12, the system will use pattern recognition or clustering algorithms to automatically detect and separate multiple voltage fluctuation regions with different disturbance characteristics. For each identified fluctuation region, the system will perform precise quantitative analysis to extract key features such as its region location, fluctuation peak value, and harmonic spectrum, thereby forming multiple clearly defined and measurable sub-voltage fluctuation ranges.

[0042] The system will perform correlation analysis and root cause tracing on all sub-voltage fluctuation ranges to determine whether they are isolated events or chain reactions caused by the same root cause. Sub-ranges with strong correlations will be merged to form one or more comprehensive voltage fluctuation ranges that can fully reflect the overall voltage stability of the system.

[0043] Specifically, the system performs pattern recognition on the voltage dynamics of the park and successfully separates two independent fluctuation regions. The first is in sub-region Z1 (precision instrument area), where all node voltages are superimposed with similar harmonic ripples, and is therefore marked as fluctuation region c: harmonic pollution area. The second is in sub-region Z2 (motor impact area), where the system identifies an impending severe voltage transient drop based on the predicted signal, and is therefore marked as fluctuation region d: transient drop area.

[0044] The system then quantifies the two fluctuation regions. For fluctuation region c, the system extracts that the THD of the test point N1, located at the end of feeder F1, is as high as 8.5%, with the 5th and 7th harmonics being the main components. These characteristics constitute the first sub-fluctuation range. For fluctuation region d, the system predicts that the test point N2, located at the end of feeder F2, will experience a depth transient drop of approximately -5.9% within 50ms. This quantification constitutes the second sub-fluctuation range.

[0045] The system matches and integrates the two sub-fluctuation ranges. Through correlation analysis, the system confirms that harmonic pollution and transient voltage drops are unrelated in time and weakly coupled electrically, and are caused by two independent disturbance sources (the frequency converter of Z1 and the large motor of Z2). Therefore, the system does not merge them, but ultimately defines the overall voltage fluctuation range of the park as a composite voltage fluctuation scenario that simultaneously includes persistent harmonic pollution problems (the first sub-fluctuation range) and predictive transient voltage drops (the second sub-fluctuation range), which requires coordinated management.

[0046] Furthermore, multiple load parameters of the power grid topology model are collected, and the load condition of the power grid topology model is determined based on the identification of multiple load parameters. The first-level constant voltage control content is determined based on the voltage fluctuation range and the load condition of the power grid topology model, which takes into account both the voltage fluctuation range and the load condition of the power grid topology model, ensuring the accuracy of the first-level constant voltage control content.

[0047] At this point, the system will comprehensively collect the static and dynamic parameters of each load in the power grid topology model, including rated power, load type, real-time power, harmonic spectrum and startup characteristics. The system will integrate and refine these scattered parameters, and through cluster analysis and overall characteristic evaluation, identify the key operating conditions of the power grid, such as heavy load, light load, impulsive or high harmonic pollution conditions, thereby forming a macroscopic description of the overall load-side operating status.

[0048] The system matches the voltage fluctuation range identified by S131 with the current load conditions to determine the root cause, and formulates quantifiable and executable control objectives for each specific voltage problem. These objectives together constitute the first layer of constant voltage control, providing a clear list of requirements for the design of subsequent control strategies.

[0049] Specifically, the system collects detailed parameters of key loads from the park's topology model and SCADA database; for example, 20 CNC machine tools in Zone Z1 (precision instrument zone) are identified as nonlinear loads of frequency converter type, with the 5th harmonic current content of a single machine reaching as high as 20% of the fundamental wave; the 250kW asynchronous motor in Zone Z2 (motor impact zone) has starting parameters showing a starting current multiple of 7 times and a starting time of up to 12 seconds.

[0050] The system integrates and analyzes the above parameters and concludes that the park is currently in a mixed operating condition. Specifically, Zone Z1 is identified as a zone with both high harmonic sensitivity and pollution, where the load is both a harmonic source and extremely sensitive to power quality. Zone Z2 is identified as a typical impact-sensitive operating condition zone. At the same time, the CNC machine tools in Zone Z1 are marked as critical loads, and their stable operation is of paramount importance.

[0051] The system accurately matches the voltage fluctuation problem identified by S131 with the current load conditions. For the first sub-fluctuation range (harmonic pollution) and the high harmonic pollution conditions in the Z1 region, the system has formulated control measures: selective harmonic compensation is implemented at the assessment point N1, with the goal of reducing THD to below 4%, focusing on suppressing the 5th and 7th harmonics. For the second sub-fluctuation range (transient drop) and the impact conditions in the Z2 region, the system has formulated another control measure: dynamic voltage support is implemented at the assessment point N2, with the goal of ensuring that the voltage is not lower than 380V during motor startup by utilizing the fast response capability of the SVG.

[0052] Therefore, by acquiring the operating state of the power grid SVG, determining the second level of constant voltage control content based on the voltage fluctuation range and the operating state of the power grid SVG, and determining the corresponding constant voltage control system based on the first and second level constant voltage control content, the overall consideration of the first and second level constant voltage control content is taken into account, ensuring the accuracy of the corresponding constant voltage control system. At the same time, multiple closed-loop control regions are introduced to further control the voltage dynamic diagram, which is compatible with the voltage fluctuation range, the load condition of the power grid topology model, and the operating state of the power grid SVG, thus improving the accuracy of the constant voltage control body.

[0053] At this time, the system will acquire the operating status of the SVG in real time at millisecond intervals, including its operating mode, available reactive power capacity, DC bus voltage, thermal status and fault information, in order to accurately assess the real-time capability boundary of the actuator; the system will match and verify the first level of constant voltage control content (demand-side target) defined in S132 with the real-time operating status of the SVG (supply-side capability), determine the feasibility of each control target, and optimize the algorithm for feasible strategies, such as selecting a suitable control algorithm, setting a dead zone or enabling a specific optimization loop, thereby forming a specific and refined second level of constant voltage control content; The system perfectly integrates the first and second layers of content, designing a complete constant voltage control system that includes an overall objective, control modules, collaborative mechanisms, and adaptive logic. It then instantiates this system into specific parameters that can be downloaded to the SVG controller, forming a closed-loop control scheme that can be deployed immediately.

[0054] Specifically, the system polls the SVG controller in real time to confirm that it is in normal operating mode, the DC bus voltage is stable, the temperature is normal, and it has an available reactive power capacity of up to ±180kvar, which is sufficient. The system performs feasibility verification and optimization of the control objectives of S132. According to calculations, the total demand for the two tasks of harmonic mitigation (requiring +30kvar) and voltage support (requiring +120kvar) is about +150kvar, which is completely within the capacity of the SVG. Therefore, the system decides to execute them in a coordinated manner and optimize the control strategy: a quasi-PR controller is used for harmonic mitigation to achieve high-precision tracking, and a PI controller with feedforward compensation is used for voltage support to achieve millisecond-level fast response. At the same time, a total power limit is set to ensure safety.

[0055] The system integrates the above content to build a dedicated load-adaptive reactive power-voltage-harmonic collaborative control system for the park. The system clarifies the overall target of THD < 4% at point N1 and voltage > 380V at point N2, designs a collaborative architecture including dual voltage controllers, harmonic controllers and power limiting modules, and sets adaptive logic to temporarily improve response speed when the motor starts. The system converts this architecture into specific controller parameters (such as the gain and constant of PI and PR controllers) and sends them to the SVG's DSP to make them take effect immediately.

[0056] refer to Figure 5 In step S14, the specific steps are as follows: S141: Real-time monitoring of the constant voltage control system, identification of the constant voltage control system, and output of multiple constant voltage control signals. Based on the tracing of each constant voltage control signal, the corresponding constant voltage control measures are determined to identify multiple constant voltage control measures. S142: Determine the control priority of multiple constant voltage control measures based on multiple constant voltage control measures and the application scenario of the power grid SVG. At the same time, collect the real-time power of the power grid topology model and determine the first-level constant voltage advantage content based on the real-time power of the power grid topology model and the control content of multiple constant voltage control measures. S143: Determine the second level of constant voltage advantage content based on the real-time power of the power grid topology model and the control priority of multiple constant voltage control measures. Determine the final constant voltage control event based on the matching of the first level of constant voltage advantage content and the second level of constant voltage advantage content.

[0057] In the embodiments of this application, the constant voltage control system is monitored in real time, the constant voltage control system is identified, and multiple constant voltage control signals are output. The corresponding constant voltage control measures are determined based on the tracing of each constant voltage control signal, so as to determine multiple constant voltage control measures. This takes into account the overall consideration of tracing each constant voltage control signal and ensures the accuracy of the corresponding constant voltage control measures.

[0058] At this time, the system will monitor all key variables in the constant voltage control system in real time with a high sampling rate. By comparing the real-time values ​​with preset target values ​​and thresholds, the system's operating status will be identified. Once a deviation from the target is detected, such as excessive harmonics or voltage drop, the system will immediately generate and output one or more abstract constant voltage control signals as trigger flags.

[0059] Based on these activated control signals, the system traces them by querying the internal signal-measure mapping table, transforming each signal into a specific, executable constant voltage control measure. Each measure defines in detail the control objective, the control algorithm to be invoked, the execution parameters, and the estimated resource consumption, thus clarifying the abstract alarm into a series of action plans to be executed.

[0060] Specifically, the system monitors the park's control system in real time at a frequency of 1kHz. At a certain moment, the system detects that the THD of the assessment point N1 is 8.6%, exceeding the target threshold of 4%, and therefore generates and outputs Signal_Harmonic_N1_Exceeded (N1 point harmonic exceedance signal). Almost simultaneously, the system receives an imminent start-up warning signal from the large motor in zone Z2 through the PLC interface and identifies a slight voltage drop trend at point N2, thereby generating Signal_VoltageSag_N2_Imminent (N2 point voltage drop warning signal).

[0061] The system traces the two activated signals mentioned above. For Signal_Harmonic_N1_Exceeded, the system traces and determines the first constant voltage control measure: the goal is to suppress the THD at point N1 to below 4%, which is achieved by activating a quasi-PR controller for the 5th and 7th harmonics, estimated to require +30kvar capacity. For Signal_VoltageSag_N2_Imminent, the system traces and determines the second constant voltage control measure: the goal is to support the voltage at point N2 to be no less than 380V, which is achieved by activating a PI voltage controller with feedforward compensation, estimated to require +120kvar capacity.

[0062] Furthermore, the control priorities of multiple constant voltage control measures are determined based on the usage scenarios of the power grid SVG. At the same time, the real-time power of the power grid topology model is collected. Based on the real-time power of the power grid topology model and the control content of multiple constant voltage control measures, the first-level constant voltage advantage content is determined. This approach takes into account both the real-time power of the power grid topology model and the control content of multiple constant voltage control measures, ensuring the accuracy of the first-level constant voltage advantage content.

[0063] At this point, the system will assign a control priority to each constant voltage control measure based on the SVG's usage scenario and the preset power grid operation strategy. This priority usually follows the order of safety and stability, critical production assurance, power quality compliance, and economic optimization. The system will collect real-time power data related to each measure in the power grid topology model to quantitatively assess the scale of the load and the intensity of the disturbance source, thereby determining the urgency of each measure.

[0064] The system comprehensively and weights the priority (importance) of each measure with its associated real-time power (urgency / scale), and identifies the control measure with the highest comprehensive score as the first priority constant voltage advantage, which serves as the core focus of the current control decision.

[0065] Specifically, based on the core mission of the park's SVG to ensure the stable operation of key production equipment, the system assigns priorities to the two measures generated by S141. The first measure (voltage support at point N2) aims to prevent the failure of large motors to start, which is directly related to production continuity and is given the highest priority 1. The second measure (harmonic control at point N1) aims to improve product quality, which is important but less urgent and is given the second highest priority 2.

[0066] The system collects relevant data via SCADA; the power of the motor in zone Z2, associated with the first measure, will jump to 250kW at startup; the total power of the CNC machine tool in zone Z1, associated with the second measure, will stabilize at 200kW; the system conducts a comprehensive evaluation; although the load power associated with both measures is large, the first measure has the highest priority and is dealing with an impending severe transient process, making its importance and urgency overwhelmingly greater than the second measure; therefore, the system ultimately identifies the constant voltage control first measure (dynamic voltage support at point N2) as the primary constant voltage advantage, clarifying that ensuring successful motor startup is the overriding top priority.

[0067] Therefore, the second level of constant voltage advantage content is determined based on the real-time power of the power grid topology model and the control priority of multiple constant voltage control measures. The final constant voltage control event is determined based on the matching of the first and second level of constant voltage advantage content. This approach takes into account the overall consideration of matching the first and second level of constant voltage advantage content, ensuring the accuracy of the final constant voltage control event.

[0068] At this point, the system will accurately analyze whether there are still resources left to process other secondary tasks after executing the first level of constant voltage advantage content, based on the real-time power of the power grid and the available capacity of the SVG. At the same time, it will detect whether there are resource or target conflicts. Based on this analysis, the system determines the second level of constant voltage advantage content. It may be a supplement to the first level of content when resources are sufficient, or it may contain only the first level of content when resources are limited.

[0069] The system matches and integrates the advantages of the first and second layers, and encapsulates the integrated control scheme into a structured and standardized constant voltage control event. The constant voltage control event contains all necessary information such as target device, control mode, specific reference value, power limit, etc., and is issued to the SVG controller as a complete instruction set to trigger its immediate execution.

[0070] Specifically, the system conducts a feasibility analysis; executing the first priority (first measure: voltage support at point N2) requires +120kvar capacity, while the available SVG capacity is +180kvar, leaving +60kvar remaining after execution; since the secondary task (second measure: harmonic mitigation at point N1) only requires +30kvar, and the two do not conflict in the control loop, the system decides to ensure the primary task while also taking into account the secondary task; therefore, the second priority of constant voltage is determined to be a combination of the first and second measures.

[0071] The system integrates these two compatible measures, vector-superimposing their reactive power commands in the SVG's current inner loop. Subsequently, the system encapsulates this integrated control scheme into a unique, structured control event, which explicitly specifies the target device, the cooperative control mode, the dynamic voltage support command for point N2, the selective harmonic compensation command for point N1, and the +150kvar total power limit. This complete control event is immediately sent to the SVG's DSP, triggering its cooperative execution of the two tasks.

[0072] refer to Figure 6 In step S15, the specific steps are as follows: S151: Determine the distribution map of the power grid topology model based on the detection of the power grid topology model, determine the first circuit control path based on the constant voltage control event and the distribution map of the power grid topology model, determine the second circuit control path based on the constant voltage control event and the power grid SVG, and determine the circuit control area based on the synthesis of the first circuit control path and the second circuit control path. S152: Perform amplitude limiting control on the circuit control area, determine the corresponding amplitude limiting control content based on the amplitude limiting control of the circuit control area, and determine the steady-state event of the circuit control area according to the amplitude limiting control content, the regional location of the circuit control area and the corresponding voltage fluctuation range; S153: Determine the first voltage steady-state coefficient based on the steady-state events and voltage dynamics of the circuit control region, determine the second voltage steady-state coefficient based on the steady-state events and SVG operating state of the circuit control region, and determine the corresponding voltage steady-state system according to the mapping relationship between the first voltage steady-state coefficient, the second voltage steady-state coefficient and the voltage steady-state system.

[0073] In the embodiments of this application, the distribution map of the power grid topology model is determined based on the detection of the power grid topology model, the first circuit control path is determined based on the constant voltage control event and the distribution map of the power grid topology model, the second circuit control path is determined based on the constant voltage control event and the power grid SVG, and the circuit control area is determined based on the synthesis of the first circuit control path and the second circuit control path. This approach is compatible with the overall consideration of the synthesis of the first circuit control path and the second circuit control path, ensuring the accuracy of the circuit control area.

[0074] At this point, the system will detect the power grid topology model and associate it with geographic information to generate a power grid distribution map that includes electrical connections and physical locations. The system will parse the target nodes in the control events and use graph theory algorithms to search for the shortest electrical path from the SVG grid connection point to these target nodes on the distribution map, which is the first circuit control path.

[0075] The system will deeply analyze the specific instructions of the control event and, based on the internal hardware topology of the SVG, map these instructions into a complete process from control calculation to power output within the device, namely the second circuit control path. The system will logically synthesize the first path, representing the external electrical corridor, and the second path, representing the internal implementation mechanism, thereby defining a physical range with the SVG as the core and the first path as the boundary. This range is the circuit control area affected by this control event.

[0076] Specifically, the system loads the power grid model of the park and associates it with GIS data to generate a visual distribution map that clearly shows the location of the SVG in the power distribution room, as well as the specific routes of feeder F1 leading to Z1 area (including point N1) and feeder F2 leading to Z2 area (including point N2).

[0077] The system identifies the target nodes of the control event as N1 and N2, and searches for two shortest paths on the distribution map: one is SVG>Main Bus>Feeder F1>N1, and the other is SVG>Main Bus>Feeder F2>N2. These two paths together constitute the external electrical corridor for this control, namely the first circuit control path.

[0078] The system analyzes the control event and outputs the fundamental reactive power and harmonic reactive power commands simultaneously. Based on the three-level topology of the SVG, it maps them to the complete internal process of the device: after the DSP receives the command, the main controller and harmonic controller work together to generate a superimposed modulation signal, which ultimately drives the IGBT to switch and output the required power. This internal process constitutes the second circuit control path.

[0079] The system combines the external paths (feeders F1 and F2) with the internal mechanisms to ultimately define a complete circuit control area. This area is centered on the SVG, with the boundary being the full length of feeders F1 and F2. It includes the main bus, related circuit breakers, and all load areas (Z1, Z2, Z3, Z4) connected by these two feeders.

[0080] Furthermore, amplitude limiting control is applied to the circuit control area. Based on the amplitude limiting control of the circuit control area, the corresponding amplitude limiting control content is determined. The steady-state event of the circuit control area is determined according to the amplitude limiting control content, the location of the circuit control area, and the corresponding voltage fluctuation range. This approach takes into account the overall consideration of amplitude limiting control content, the location of the circuit control area, and the corresponding voltage fluctuation range, ensuring the accuracy of the steady-state event of the circuit control area.

[0081] At this time, the system will set multi-dimensional safety limits for all key equipment, nodes and lines within the circuit control area, including the output power of the SVG, the upper and lower voltage limits of the nodes and the current carrying capacity of the lines, and can be dynamically adjusted according to real-time operating conditions. The system transforms these abstract limit values ​​into specific, executable monitoring and intervention actions, namely limit control content. Limit control content presents the graded intervention measures that should be taken when the system approaches or touches the safety boundary, such as adjusting controller parameters or activating hard limit.

[0082] The system integrates these safety constraints with the original control objectives at specific physical locations, ultimately forming a steady-state event containing a target-constraint-location triplet, which serves as a behavioral guideline that must be followed at all times during control execution.

[0083] Specifically, the system sets specific safety boundaries for the park's controlled area: the output power of the SVG is rigidly limited to 180kvar; the voltage safety range of all nodes is set to 342V to 418V; and the current limit of feeders F1 and F2 is set to 380A.

[0084] The system translates the above limiting into executable control content: for example, setting a power limiting module in the SVG controller to force clamping when the command exceeds 180kvar; continuously monitoring the voltage at points N1 and N2, and switching the SVG to inductive mode to absorb excess reactive power once it exceeds 415V; and setting a line current alarm in SCADA.

[0085] The system integrates safety constraints with the control objectives determined in S131 to generate specific steady-state events. For example, for harmonic mitigation at point N1, steady-state event 1 is generated: harmonic compensation is performed at point N1 to reduce THD, but it must be ensured that the voltage at this point does not exceed 415V during the process, and the total SVG capacity occupied and other measures do not exceed 180kvar. Similarly, for voltage support at point N2, steady-state event 2 is generated: +120kvar reactive power needs to be output to support the motor starting voltage, but the total output power of the SVG must be strictly limited within the safe limit of 180kvar.

[0086] Therefore, a first-level voltage steady-state coefficient is determined based on the steady-state events and voltage dynamics of the circuit-controlled region, and a second-level voltage steady-state coefficient is determined based on the steady-state events and the operating state of the SVG (Static Var Generator) in the circuit-controlled region. The corresponding voltage steady-state system is determined according to the mapping relationship between the first-level voltage steady-state coefficient, the second-level voltage steady-state coefficient, and the voltage steady-state system. This approach incorporates a holistic consideration of the mapping relationship between the first-level voltage steady-state coefficient, the second-level voltage steady-state coefficient, and the voltage steady-state system, ensuring the accuracy of the corresponding voltage steady-state system. Simultaneously, a constant voltage control event is introduced to control the steady-state events in the circuit-controlled region, achieving a holistic consideration of the steady-state events, voltage dynamics, and the operating state of the power grid SVG in the circuit-controlled region, thus improving the accuracy of the voltage steady-state system.

[0087] At this point, the system will compare the real-time operating status of the power grid (voltage dynamic graph) with the preset targets and constraints (steady-state events) to calculate a series of first-level voltage steady-state coefficients that reflect the effect of external control, such as voltage accuracy, power quality, and system stability margin. At the same time, the system will continuously monitor the internal operating status of the SVG and, in combination with the performance requirements of steady-state events, calculate a series of second-level voltage steady-state coefficients that reflect the health and efficiency of the actuator itself, such as equipment health, operating efficiency, and thermal stability margin.

[0088] The system inputs these two steady-state coefficients into a preset mapping model. This model dynamically outputs adjustment instructions for the control system based on the comprehensive internal and external conditions. For example, it may fine-tune controller parameters to optimize performance or actively dredge the device to ensure safety when it overheats. Through this continuous perception-evaluation-adjustment cycle, a voltage steady-state system that can operate autonomously at a safe, efficient, and high-quality balance point over a long period of time is finally formed. Under the premise of ensuring safety and quality, the voltage steady-state system autonomously finds and maintains itself at the optimal operating balance point.

[0089] Specifically, after the motor starts, the system evaluates the control effect and obtains various coefficients: the voltage at point N2 is only 2V lower than the target value, and the voltage accuracy coefficient is excellent; the THD at point N1 is suppressed to 3.8%, and the power quality coefficient meets the standard; the SVG output power still has a margin of 45kvar from the limit, and the system stability margin coefficient is sufficient; the system power factor is significantly improved, and the economic coefficient is good.

[0090] The system synchronously assesses the SVG's own status and concludes that: the IGBT temperature is far below the alarm value, indicating good equipment health; the conversion efficiency is 98.2%, indicating high operating efficiency; and the dynamic response and thermal stability margin both indicate that the SVG is in a healthy state with strong coping capabilities.

[0091] The system inputs the aforementioned two coefficients into the optimization model to construct and continuously optimize the voltage steady-state system of the park. For example, if the model detects a slight fluctuation in the harmonic at point N1 during motor startup, it automatically fine-tunes the parameters of the harmonic PR controller to enhance stability in order to improve the power quality coefficient. At the same time, the model pre-generates a backup strategy based on the equipment health coefficient and ambient temperature: if multiple consecutive motor startups are detected, the harmonic mitigation target is appropriately relaxed to reduce SVG heating. Through this continuous dynamic adjustment, the park's control system evolves into an intelligent voltage steady-state system, which autonomously finds and maintains itself at the optimal operating equilibrium point while ensuring safety and quality.

[0092] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of the constant voltage control device for the power grid SVG in an embodiment of the present invention; the constant voltage control device for the power grid SVG includes: The power grid topology path module 21 is used to construct a corresponding power grid topology model based on the parallel connection of the power grid SVG and the low-voltage busbars of the distribution transformer, determine the power grid topology path based on the identification of the power grid topology model, and mark multiple power grid topology nodes. The voltage dynamic graph module 22 is used to determine the multi-loop control region based on the node position of each power grid topology node, the corresponding voltage parameters, and the harmonic control command, and to determine the voltage dynamic graph based on the multi-loop control region, multiple voltage parameters, and the working state of the power grid SVG. The constant voltage control system module 23 is used to determine the corresponding voltage fluctuation range based on the identification of the voltage dynamic diagram, and to determine the corresponding constant voltage control system according to the voltage fluctuation range, the load condition of the power grid topology model and the working state of the power grid SVG. The constant voltage control event module 24 is used to determine multiple constant voltage control measures based on the identification of the constant voltage control system in the constant voltage control system, and to determine the final constant voltage control event based on the control content of the multiple constant voltage control measures, the corresponding control priority and the real-time power of the power grid topology model. The voltage steady-state system module 25 is used to determine the circuit control area based on the constant voltage control event, the distribution map of the power grid topology model and the power grid SVG, determine the steady-state event of the circuit control area based on the amplitude limiting control of the circuit control area, and construct the corresponding voltage steady-state system based on the steady-state event of the circuit control area, the voltage dynamic map and the working state of the power grid SVG.

[0093] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A constant voltage control method for a power grid SVG, characterized in that, include: A corresponding power grid topology model is constructed based on the parallel connection of the low-voltage busbars of the power grid SVG and distribution transformers. The power grid topology path is determined based on the identification of the power grid topology model, and multiple power grid topology nodes are marked. The multi-loop control region is determined based on the node location, corresponding voltage parameters, and harmonic control commands of each power grid topology node. The voltage dynamic diagram is determined based on the multi-loop control region, multiple voltage parameters, and the working state of the power grid SVG. The voltage dynamic diagram presents a voltage distribution cloud map, a sensitivity heat map, and a disturbance trajectory prediction. Based on the identification of the voltage dynamic diagram, the corresponding voltage fluctuation range is determined, and the corresponding constant voltage control system is determined according to the voltage fluctuation range, the load condition of the power grid topology model and the working state of the power grid SVG. In the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined according to the control content of the multiple constant voltage control measures, their corresponding control priorities, and the real-time power of the power grid topology model. The constant voltage control event includes the target device, control mode, specific reference value, and power limit. Based on constant voltage control events, the distribution map of the power grid topology model, and the power grid SVG, the circuit control area is determined. The steady-state events of the circuit control area are determined according to the amplitude limiting control of the circuit control area. Based on the steady-state events of the circuit control area, the voltage dynamic diagram, and the working state of the power grid SVG, the corresponding voltage steady-state system is constructed. The amplitude limiting control content presents the graded intervention measures that should be taken when the system approaches or touches the safety boundary.

2. The constant voltage control method for power grid SVG according to claim 1, characterized in that, The corresponding power grid topology model is constructed based on the parallel connection of the low-voltage busbars of the power grid SVG and distribution transformers. The power grid topology path is determined based on the identification of this topology model, and multiple power grid topology nodes are marked, including: The current location of the power grid SVG is collected, and the distribution map of the low-voltage busbar of the distribution transformer is marked. Based on the distribution map of the low-voltage busbar of the distribution transformer, the current location of the power grid SVG, and the function of the power grid SVG, the corresponding parallel system is constructed. Based on the parallel system, the distribution transformer, and the power grid SVG, the corresponding power grid topology model is constructed. The power grid topology model is identified, and multiple sub-power grid topology regions are output. The power grid topology path is determined based on the regional location and corresponding influence range of the multiple sub-power grid topology regions. Multiple power grid topology nodes are determined based on the detection of the power grid topology path.

3. The constant voltage control method for the power grid SVG according to claim 1, characterized in that, The process of determining a multi-loop control region based on the node location, corresponding voltage parameters, and harmonic control commands of each power grid topology node, and determining a voltage dynamic diagram based on this multi-loop control region, multiple voltage parameters, and the operating state of the power grid SVG, includes: In multiple power grid topology nodes, the node position of each power grid topology node is determined based on the identification of each power grid topology node, and the corresponding voltage parameters are determined based on the detection of each power grid topology node. At the same time, harmonic control commands are collected, and the first control part is determined based on the node position of each power grid topology node and the harmonic control commands. The first control part clarifies that the current core task is to perform fine harmonic compensation in the corresponding area. The second control section is determined based on the voltage parameters and harmonic control commands of each grid topology node. A multi-loop control region is then defined based on the first and second control sections. Simultaneously, the operating state of the grid SVG is determined by identifying its operating signals. A voltage dynamic diagram is then determined based on this multi-loop control region, multiple voltage parameters, and the operating state of the grid SVG. The second control section identifies key nodes with voltage over-limit risks or severe fluctuations, along with their corresponding associated paths. The multi-loop control region contains closed-loop control strategies for single or multiple objectives.

4. The constant voltage control method for power grid SVG according to claim 1, characterized in that, The process of determining the corresponding voltage fluctuation range based on the identification of the voltage dynamic diagram, and determining the corresponding constant voltage control system based on the voltage fluctuation range, the load condition of the power grid topology model, and the operating state of the power grid SVG, includes: Based on the detection of the voltage dynamic map, multiple voltage fluctuation regions are determined. Based on the regional location of each voltage fluctuation region, the corresponding regional location, and the corresponding fluctuation peak, multiple sub-voltage fluctuation ranges are determined. Based on the matching of multiple sub-voltage fluctuation ranges, the corresponding voltage fluctuation range is determined.

5. The constant voltage control method for a power grid SVG according to claim 4, characterized in that, The process of determining the corresponding voltage fluctuation range based on the identification of the voltage dynamic diagram, and determining the corresponding constant voltage control system based on the voltage fluctuation range, the load condition of the power grid topology model, and the operating state of the power grid SVG, further includes: Multiple load parameters of the power grid topology model are collected, and the load condition of the power grid topology model is determined based on the identification of multiple load parameters. The first level of constant voltage control content is determined based on the voltage fluctuation range and the load condition of the power grid topology model. The operating status of the power grid SVG is obtained. Based on the voltage fluctuation range and the operating status of the power grid SVG, the second level of constant voltage control content is determined. Based on the first level of constant voltage control content and the second level of constant voltage control content, the corresponding constant voltage control system is determined.

6. The constant voltage control method for a power grid SVG according to claim 1, characterized in that, In the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined according to the control content of these multiple constant voltage control measures, their corresponding control priorities, and the real-time power of the power grid topology model. This includes: The system monitors the constant voltage control system in real time, identifies the system, and outputs multiple constant voltage control signals. Based on the tracing of each constant voltage control signal, the corresponding constant voltage control measures are determined, thus identifying multiple constant voltage control measures.

7. The constant voltage control method for a power grid SVG according to claim 6, characterized in that, In the constant voltage control system, multiple constant voltage control measures are determined based on the identification of the constant voltage control system. The final constant voltage control event is determined based on the control content of the multiple constant voltage control measures, their corresponding control priorities, and the real-time power of the power grid topology model. This also includes: Based on multiple constant voltage control measures and the application scenarios of the power grid SVG, the control priority of multiple constant voltage control measures is determined. At the same time, the real-time power of the power grid topology model is collected, and the first-level constant voltage advantage content is determined based on the real-time power of the power grid topology model and the control content of multiple constant voltage control measures. The second level of constant voltage advantage content is determined based on the real-time power of the power grid topology model and the control priority of multiple constant voltage control measures. The final constant voltage control event is determined based on the matching of the first level of constant voltage advantage content and the second level of constant voltage advantage content.

8. The constant voltage control method for a power grid SVG according to claim 1, characterized in that, The circuit control region is determined based on constant voltage control events, the distribution map of the power grid topology model, and the power grid SVG. The steady-state events of the circuit control region are determined based on the limiting control within this region. A corresponding steady-state voltage system is constructed based on the steady-state events of this circuit control region, the voltage dynamic map, and the operating state of the power grid SVG, including: The distribution map of the power grid topology model is determined based on the detection of the power grid topology model. The first circuit control path is determined based on the constant voltage control event and the distribution map of the power grid topology model. The second circuit control path is determined based on the constant voltage control event and the power grid SVG. The circuit control area is determined based on the synthesis of the first circuit control path and the second circuit control path.

9. The constant voltage control method for a power grid SVG according to claim 8, characterized in that, The method of determining the circuit control region based on constant voltage control events, the distribution map of the power grid topology model, and the power grid SVG, determining the steady-state events of the circuit control region based on the amplitude limiting control of the circuit control region, and constructing the corresponding voltage steady-state system based on the steady-state events of the circuit control region, the voltage dynamic diagram, and the operating state of the power grid SVG, further includes: Amplitude limiting control is applied to the circuit control area. Based on the amplitude limiting control of the circuit control area, the corresponding amplitude limiting control content is determined. The steady-state event of the circuit control area is determined according to the amplitude limiting control content, the regional location of the circuit control area, and the corresponding voltage fluctuation range. The first voltage steady-state coefficient is determined based on the steady-state events and voltage dynamics of the circuit control region. The second voltage steady-state coefficient is determined based on the steady-state events and the operating state of the SVG in the circuit control region. The corresponding voltage steady-state system is determined according to the mapping relationship between the first voltage steady-state coefficient, the second voltage steady-state coefficient, and the voltage steady-state system.

10. A constant voltage control device for a power grid SVG, characterized in that, The constant voltage control device of the power grid SVG is applied to the constant voltage control method of the power grid SVG as described in any one of claims 1-9.

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