A method and device for cooperative control of on-load tap-changing and adaptive reactance of a current transformer regulator and a storage medium

Abstract

The embodiment of the application discloses a kind of load tap changer and adaptive reactance of current transformer coordinated control method, device and storage medium, method includes: the load tap changer of current transformer is with adaptive reactor and forms joint control unit, obtains the transient security index of each joint control unit;Exchange the transient security index between adjacent converter station, and based on transient security index, combined with electrical coupling relationship, collaborative generation is used to characterize commutation instability state system-level operation forbidden zone description, form collaborative security constraint quantity;According to collaborative security constraint quantity and system-level operation forbidden zone, determine security condition;When collaborative security constraint quantity meets security condition, only by continuously adjusting the reactance value of adaptive reactor to AC side voltage and current are quickly adjusted;When collaborative security constraint quantity does not meet security condition, trigger load tap changer to execute gear switching.The application significantly improves the transient stability of multi-terminal high-voltage direct current system.

Description

A method, device, and storage medium for coordinated control of on-load tap change and adaptive reactance of a converter voltage regulator. Technical Field

[0001] This application relates to the field of high voltage direct current transmission technology, and in particular to a method, device and storage medium for coordinated control of on-load tap change and adaptive reactor of a converter voltage regulator. Background Technology

[0002] Multi-terminal high-voltage direct current (MTDC) transmission systems play a crucial role in long-distance, high-capacity power transmission and renewable energy integration. However, in multi-infeed DC (MIDC) systems, strong electrical coupling exists between converter stations. When disturbances occur on the AC side, commutation failure can easily occur, leading to transient overcurrent, firing angle shift, and reduced arc-extinguishing angle, seriously threatening the safe and stable operation of the system.

[0003] Traditional control methods often employ local independent regulation, such as discretely adjusting the transformer ratio of the converter voltage regulator through on-load tap changers (OLTCs) or compensating for reactive power through fixed reactors. However, these methods have the following drawbacks: local regulation ignores the multi-infeed coupling effect, which may lead to the overall system entering a commutation instability state; frequent mechanical actions of on-load tap changers shorten their lifespan; and continuous regulation methods have limited response speed and cannot effectively suppress rapid transient processes.

[0004] While existing technologies include preventive control measures for commutation failure (such as the CFPREV strategy) and reactive power compensation coordination research, there is a lack of distributed coordination mechanisms that combine on-load tap changers with adaptive reactors, making it impossible to achieve priority continuous regulation and necessary discrete switching under system-level safety constraints. Summary of the Invention

[0005] This application provides a method, device, and storage medium for the coordinated control of on-load tap changer and adaptive reactor in a converter voltage regulator, which realizes optimized coordination between on-load tap changer and adaptive reactor, and significantly improves the transient stability of multi-terminal high-voltage DC system.

[0006] This application provides the following solution:

[0007] According to the first aspect, a collaborative control method for on-load tap changer and adaptive reactor of converter voltage regulator is provided. The method includes: in each converter station of a multi-terminal high-voltage direct current transmission system, forming a joint control unit with the on-load tap changer of the converter voltage regulator and the adaptive reactor; obtaining transient safety indicators characterizing the commutation safety state in real time based on local measurement information from each joint control unit; exchanging the transient safety indicators between the joint control units of adjacent converter stations; and based on the exchanged transient safety indicators, combined with the electrical coupling relationship of each converter station in the multi-feed DC system, collaboratively generating a system-level operational restricted area description characterizing the commutation instability state, and forming a collaborative safety constraint quantity. The full constraint is used to limit the regulation behavior of each joint control unit to prevent local regulation from causing the system operating state to enter the restricted operating zone. The safety conditions are determined based on the relative positional relationship between the cooperative safety constraint and the system-level restricted operating zone description. When the cooperative safety constraint meets the safety conditions, the AC side voltage and current are rapidly regulated by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range. When the cooperative safety constraint does not meet the safety conditions, the on-load tap changer is triggered to perform a tap position switch to change the equivalent voltage regulation structure of the converter station, and the adjustment range of the adaptive reactor is redefined after the tap position switch.

[0008] According to one achievable method in the embodiments of this application, the method further includes: the system-level operation restricted area description maps the transient safety indicators of each converter station to a unified transient operation state space, and jointly limits the region corresponding to the commutation instability state in the transient operation state space based on the electrical coupling strength between converter stations in the multi-infeed DC system.

[0009] According to one of the embodiments of this application, the method further includes: the system-level operational restricted area description is updated in real time according to the changing trend of transient safety indicators of each converter station, so that the restricted area boundary can adaptively shrink or expand with the changes in system transient response speed and coupling state.

[0010] According to one achievable method in the embodiments of this application, based on the electrical coupling strength between converter stations in a multi-infeed DC system, the region corresponding to the commutation instability state in the transient operating state space is jointly defined, including: obtaining electrical coupling parameters between each converter station in the multi-infeed DC system, wherein the electrical coupling parameters include at least equivalent AC impedance, short-circuit ratio, or power mutual influence coefficient; determining the influence weight of the transient safety index of each converter station on the commutation stability of the system based on the electrical coupling parameters; mapping the transient safety index of each converter station to the transient operating state space according to the influence weight; and jointly superimposing the commutation instability criteria of multiple converter stations in the transient operating state space to construct a system-level commutation instability region boundary reflecting the multi-infeed coupling effect.

[0011] According to one achievable method in this application embodiment, determining safety conditions based on the relative positional relationship between the cooperative safety constraint quantity and the system-level operational restricted zone description includes: constructing a multi-dimensional safety determination space characterizing the critical boundary of system commutation instability based on the system-level operational restricted zone description, wherein the multi-dimensional safety determination space uses the transient safety index and its changing trend as coordinate axes; mapping the cooperative safety constraint quantity formed by each joint control unit to the multi-dimensional safety determination space to obtain the corresponding system operating state point; and dynamically generating a safety determination criterion characterizing whether the system operating state allows for continued continuous adjustment based on the spatial positional relationship between the system operating state point and the critical boundary of commutation instability.

[0012] According to one achievable method in an embodiment of this application, the AC side voltage and current are rapidly adjusted by continuously adjusting the reactance value of the adaptive reactor, including: determining the continuous adjustment direction and adjustment amplitude of the adaptive reactor based on locally measured AC side voltage deviation, current change rate, and the changing trend of the transient safety index, without triggering the on-load tap changer switch; dynamically limiting the maximum adjustment rate and instantaneous adjustment range of the adaptive reactor based on the relative distance between the cooperative safety constraint and the system-level operating restricted area description; and during the continuous adjustment process, monitoring the changes in the trigger angle and arc extinguishing angle in real time, and adaptively converging the reactance adjustment amplitude when the trigger angle is detected to be close to the allowable operating boundary.

[0013] According to one achievable method in an embodiment of this application, the adjustment range of the adaptive reactor is redefined after the tap changer switches, including: obtaining the equivalent AC side voltage and equivalent impedance parameters of the converter station after the on-load tap changer completes the tap changer switching; updating the equivalent reactor adjustment range of the adaptive reactor based on the equivalent AC side voltage and equivalent impedance parameters, so that the adjustment range meets the operating constraints of the firing angle and the arc extinguishing angle; and using the updated equivalent reactor adjustment range as the allowable adjustment boundary in the subsequent continuous adjustment process.

[0014] According to a second aspect, a collaborative control device for on-load tap changer and adaptive reactor of a converter voltage regulator is provided. The device includes: a transient safety index acquisition unit, configured to, in each converter station of a multi-terminal high-voltage direct current transmission system, form a joint control unit with the on-load tap changer of the converter voltage regulator and the adaptive reactor, and acquire transient safety indices characterizing the commutation safety state in real time based on local measurement information from each joint control unit; and a restricted area description generation unit, configured to exchange the transient safety indices between the joint control units of adjacent converter stations, and, based on the exchanged transient safety indices and combined with the electrical coupling relationship of each converter station in the multi-feed DC system, collaboratively generate a system-level operational restricted area description characterizing the commutation instability state, and form a collaborative safety constraint quantity. Safety constraints are used to limit the adjustment behavior of each joint control unit to prevent local adjustments from causing the system operating state to enter the prohibited operating zone. A safety condition determination unit is configured to determine safety conditions based on the relative positional relationship between the cooperative safety constraints and the system-level prohibited operating zone description. A cooperative control execution unit is configured to, when the cooperative safety constraints meet the safety conditions, rapidly adjust the AC side voltage and current solely by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range; when the cooperative safety constraints do not meet the safety conditions, trigger the on-load tap changer to perform a range switching to change the equivalent voltage regulation structure of the converter station, and redefine the adjustment range of the adaptive reactor after the range switching.

[0015] According to a third aspect, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the first aspects above.

[0016] According to the fourth aspect, an electronic device is provided, comprising:

[0017] One or more processors; and

[0018] A memory associated with the one or more processors, the memory being used to store program instructions that, when read and executed by the one or more processors, perform the steps of the method described in any one of the first aspects above.

[0019] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0020] This application calculates and exchanges transient safety indicators in real time through the joint control unit of each converter station, collaboratively constructs a system-level operational restricted zone and generates safety constraints, effectively avoiding the risk of system commutation instability caused by neglecting the electrical coupling of multiple infeeds in traditional local independent regulation. This method prioritizes the continuous and rapid adjustment of adaptive reactors to suppress transient overcurrents and maintain stable firing angles. On-load tap changers are only triggered for discrete switching when the collaborative constraints do not meet safety conditions, and the adjustment range is redefined after switching. This significantly improves the transient stability and response speed of the system, reduces the mechanical operation frequency of on-load tap changers, extends equipment life, and enhances the overall robustness and safety of the multi-infeed DC system against AC disturbances.

[0021] Of course, any product implementing this application does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a flowchart of the coordinated control method of on-load tap change and adaptive reactor of the converter voltage regulator provided in the embodiment of this application;

[0024] Figure 2 is a structural block diagram of the coordinated control device for on-load tap change and adaptive reactor of the converter voltage regulator provided in the embodiment of this application;

[0025] Figure 3 is a schematic block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0027] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0029] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0030] Figure 1 is a flowchart of the coordinated control method for on-load tap change and adaptive reactance of a converter voltage regulator provided in an embodiment of this application. As shown in Figure 1, the method may include the following steps:

[0031] Step 101: In each converter station of the multi-terminal high-voltage direct current transmission system, the on-load tap changer of the converter voltage regulator and the adaptive reactor are combined into a joint control unit, and the transient safety index characterizing the commutation safety status is obtained by each joint control unit based on local measurement information in real time.

[0032] Step 102: Exchange the transient safety indicators between the joint control units of adjacent converter stations, and based on the exchanged transient safety indicators, combined with the electrical coupling relationship of each converter station in the multi-infeed DC system, collaboratively generate a system-level operation forbidden zone description to characterize the commutation instability state, and form a collaborative safety constraint quantity. The collaborative safety constraint quantity is used to limit the adjustment behavior of each joint control unit to prevent local adjustment from causing the system operating state to enter the operation forbidden zone.

[0033] Step 103: Determine the security conditions based on the relative positional relationship between the cooperative security constraint quantity and the system-level operational restricted area description.

[0034] Step 104: When the cooperative safety constraint meets the safety conditions, the AC side voltage and current are rapidly adjusted by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range; when the cooperative safety constraint does not meet the safety conditions, the on-load tap changer is triggered to perform tap position switching to change the equivalent voltage regulation structure of the converter station, and the adjustment range of the adaptive reactor is redefined after the tap position switching.

[0035] As can be seen from the above process, this application calculates and exchanges transient safety indicators in real time through the joint control unit of each converter station, collaboratively constructs a system-level operational restricted zone and generates safety constraints, effectively avoiding the risk of system commutation instability caused by neglecting the electrical coupling of multiple infeeds in traditional local independent regulation. This method prioritizes the continuous and rapid adjustment of adaptive reactors to suppress transient overcurrents and maintain firing angle stability. It only triggers discrete switching of on-load tap changers when the cooperative constraints do not meet the safety conditions, and redefines the adjustment range after switching. This significantly improves the transient stability and response speed of the system, reduces the mechanical operation frequency of on-load tap changers, extends equipment life, and enhances the overall robustness and safety of multi-infeed DC systems against AC disturbances.

[0036] The following describes in detail each step of the above process and the effects that can be further produced, with reference to the embodiments.

[0037] First, in conjunction with the embodiments, the above step 101, namely "in each converter station of the multi-terminal high-voltage direct current transmission system, the on-load tap changer of the converter voltage regulator and the adaptive reactor constitute a joint control unit, and each joint control unit obtains the transient safety index characterizing the commutation safety status in real time based on local measurement information", will be described in detail.

[0038] In multi-terminal high-voltage direct current (HVDC) transmission systems, each converter station is the core equipment for converting AC to DC power. To improve the system's response to transient disturbances, this application combines the on-load tap changer of the converter voltage regulator with an adaptive reactor into a joint control unit. This combination allows the two regulation methods to work collaboratively within the same control framework. The on-load tap changer is mainly responsible for discretely adjusting the transformer ratio, thereby changing the equivalent voltage level of the converter station, while the adaptive reactor can continuously and rapidly adjust the reactance value connected to the AC system, achieving dynamic compensation of reactive power. After forming a joint control unit, the two can share measurement information and control decisions, realizing a hierarchical control strategy from fast continuous regulation to slow discrete regulation.

[0039] One of the core tasks of the joint control unit is to calculate transient safety indicators in real time based on local measurement information. Local measurement information typically includes key electrical quantities such as AC side voltage, current, DC power, firing angle, and arc-extinguishing angle of the converter station. These quantities directly reflect the safety status of the current commutation process. Transient safety indicators are quantified values ​​obtained by processing this measurement information and are used to characterize the commutation safety status. For example, this indicator can comprehensively consider multiple factors such as arc-extinguishing angle margin, voltage deviation, and current change rate to form a numerical value or vector that sensitively reflects the risk of commutation failure. When the system is subjected to disturbances such as AC faults or load fluctuations, this indicator changes rapidly, thus providing timely and reliable basis for subsequent control decisions.

[0040] By independently deploying such a joint control unit at each converter station and calculating transient safety indicators in real time, the system achieves a distributed control architecture. This approach eliminates the need for a centralized upper-level controller, enabling rapid detection of commutation safety threats using only local information, thus significantly reducing response time. Furthermore, since indicator calculations are entirely based on local measurements, it avoids the latency and reliability issues that may arise from long-distance information transmission, laying a solid foundation for subsequent collaborative decision-making based on distributed communication.

[0041] The following describes in detail step 102 above, namely, "exchanging the transient safety indicators between the joint control units of adjacent converter stations, and based on the exchanged transient safety indicators, combined with the electrical coupling relationship of each converter station in the multi-infeed DC system, collaboratively generating a system-level operation forbidden zone description to characterize the commutation instability state, and forming a collaborative safety constraint quantity, which is used to limit the adjustment behavior of each joint control unit to prevent local adjustment from causing the system operating state to enter the operation forbidden zone".

[0042] In multi-terminal HVDC transmission systems, the joint control units of adjacent converter stations exchange their real-time calculated transient safety indicators through distributed communication. This exchange mechanism allows each joint control unit to not only grasp its local commutation safety status but also obtain similar information from adjacent converter stations, thus overcoming the limitations of traditional independent local control. Distributed communication typically employs high-speed and reliable inter-station data links to ensure low latency and high reliability of information transmission. This indicator exchange provides the necessary data foundation for subsequent collaborative decision-making, enabling the system to assess commutation risks in a multi-infeed environment from a holistic perspective.

[0043] Based on the transient safety indicators obtained through exchange, each joint control unit further combines the electrical coupling relationships between converter stations in the multi-infeed DC system to collaboratively generate a system-level operational restricted zone description. The electrical coupling relationship is mainly reflected in the degree of mutual influence of the AC bus voltages of the converter stations, quantified by parameters such as short-circuit ratio, equivalent AC impedance, or power interaction factor. When a converter station experiences a voltage drop or reactive power disturbance, it will be transmitted to adjacent stations through the AC system, amplifying the overall probability of commutation failure. The collaborative generation process is executed distributedly by each unit, using a unified algorithm to fuse local and adjacent transient safety indicators, ultimately forming an operational restricted zone description reflecting the commutation instability risk of the entire system. This restricted zone is a dangerous area defined in the state space; any operating state entering this area may cause multiple converter stations to experience commutation instability simultaneously or successively.

[0044] As an implementable approach, the system-level no-entry zone description in this application maps the transient safety indicators of each converter station to a unified transient operating state space, and jointly defines the regions corresponding to commutation instability states in the transient operating state space based on the electrical coupling strength between converter stations in a multi-infeed DC system.

[0045] The core of system-level operational restricted zone description lies in mapping the transient safety indicators independently calculated by each converter station to a unified transient operational state space. This mapping process enables the previously scattered local safety state information of different converter stations to be compared and comprehensively analyzed within the same coordinate framework. The unified transient operational state space is typically a multi-dimensional abstract space, whose coordinate axes can be composed of the transient safety indicators of each converter station and their derivatives. Through this mapping, the operational state of each converter station is transformed into a point or trajectory in the state space, thereby converting the complex operational status of the multi-terminal system into a geometrically visualized and operable description, providing a unified expression basis for subsequent joint risk assessment.

[0046] After completing the index mapping, the region corresponding to the commutation instability state in the transient operating state space is further jointly defined based on the electrical coupling strength between converter stations in a multi-infeed DC system. Electrical coupling strength reflects the degree of mutual influence between different converter stations through the AC system. For example, voltage disturbances at one converter station can be transmitted to other stations through the common AC power grid, thereby amplifying or inducing the risk of simultaneous commutation failure at multiple stations. The joint definition process does not simply add up the local instability boundaries of each converter station, but rather weights and fuses the contributions of coupling strength to the indices of each station, thereby delineating a prohibited region in the state space that reflects the overall commutation instability risk of the system. The boundary of this region comprehensively considers the multi-station interaction effects, enabling timely early warning when the system operating state approaches or enters this region.

[0047] Furthermore, based on the electrical coupling strength between converter stations in a multi-infeed DC system, the region corresponding to the commutation instability state in the transient operating state space is jointly defined, including: obtaining electrical coupling parameters between each converter station in the multi-infeed DC system, the electrical coupling parameters including at least equivalent AC impedance, short-circuit ratio, or power mutual influence coefficient; determining the influence weight of the transient safety index of each converter station on the commutation stability of the system according to the electrical coupling parameters; mapping the transient safety index of each converter station to the transient operating state space according to the influence weight; and jointly superimposing the commutation instability criteria of multiple converter stations in the transient operating state space to construct a system-level commutation instability region boundary reflecting the multi-infeed coupling effect.

[0048] Specifically, in multi-infeed DC systems, the process of jointly limiting the commutation instability region in the transient operating state space first requires obtaining the electrical coupling parameters between each converter station. These parameters are key to quantifying the degree of mutual influence between stations and include at least the equivalent AC impedance, short-circuit ratio, or power mutual influence coefficient. The equivalent AC impedance reflects the electrical distance between the AC buses of the converter stations; a smaller impedance indicates tighter coupling. The short-circuit ratio characterizes the support strength of the AC system for the DC system; a lower value means the system is more susceptible to disturbances. The power mutual influence coefficient directly describes the impact of a power change at one converter station on the voltage or commutation process of another station. By acquiring these parameters in real-time or near real-time, the system can accurately grasp the current coupling characteristics between multiple stations, providing a reliable data foundation for subsequent joint limiting.

[0049] After obtaining the electrical coupling parameters, the next step is to determine the weight of each converter station's transient safety index on the overall system's commutation stability based on these parameters. Due to differences in geographical location, system strength, and operating conditions, the contribution of changes in the transient safety index to the overall system stability varies among different converter stations. For example, a converter station with higher coupling strength will have a greater impact on adjacent stations if its index deteriorates; therefore, it should be assigned a higher weight. This weight determination process is typically based on mathematical models of the coupling parameters, ensuring that the weight allocation objectively reflects the actual electrical interaction relationships, thereby achieving accurate quantification of the risk contribution of each station.

[0050] After determining the weights, the transient safety indicators of each converter station are mapped to a unified transient operating state space according to their respective influence weights. This mapping is not a simple side-by-side placement, but a weighted projection, so that the indicators of closely coupled converter stations occupy a larger range of influence in the state space. In this way, the originally independent local indicators are transformed into coordinate points or trajectories with global significance, and the location of the operating point in the state space can comprehensively reflect the system risk level under multi-station coupling.

[0051] Finally, in the transient operating state space, the commutation instability criteria of multiple converter stations are jointly superimposed to construct a system-level commutation instability region boundary reflecting the multi-infeed coupling effect. This superposition process is not a mechanical addition, but a nonlinear fusion considering weights, forming a continuous, smooth, and dynamic boundary curve or surface. This boundary accurately characterizes when the system will enter a commutation instability state under the interaction of multiple stations, and compared with the independent criteria of a single station, it is better able to capture the cascading risks induced by coupling.

[0052] For combined overlay, it can be achieved in the following way: First, for each converter station Define a local commutation instability risk function ,in This refers to the station's transient safety indicators (e.g., the reciprocal of the normalized arc-extinguishing angle margin or the comprehensive value of voltage deviation). The function is designed to be used when... When within a safe range Approaching 0, when approaching or exceeding the local instability threshold To address rapid increases, a sigmoid function or a piecewise linear function can be used to achieve high sensitivity near the critical point.

[0053] Secondly, electrical coupling weights are introduced. , indicating converter station Converter station The strength of the coupling effect. This weight can be calculated based on the obtained electrical coupling parameters, such as... ,in for and The equivalent AC impedance between them for right Multiple feed-in interaction factors The reference impedance is used. This weight satisfies... And the closer the coupling between the two stations, the better. The larger the diagonal element This indicates that this website itself has the greatest impact.

[0054] Then, within a unified transient operating state space, the local risk functions of each converter station are weighted and superimposed to construct a system-level comprehensive risk function. This superposition means that not only will the deterioration of the indicators at this station directly contribute to the system risk, but the deterioration of the indicators at neighboring stations will also indirectly amplify the contribution to the overall risk through the coupling weights, thus reflecting the multi-feedback interaction effect.

[0055] Finally, the boundary of the system-level commutation instability region is defined by setting a comprehensive risk threshold. Determined, that is The area was designated a restricted zone. Threshold It can be calibrated using offline simulation or historical fault data to ensure that it is triggered precisely in typical multi-station simultaneous instability cases. Through this weighted superposition method, the forbidden zone boundary in the state space is no longer a simple union of the local boundaries of each station, but exhibits a nonlinear contraction or distortion shape. The boundary is closer to the safe zone in the direction of strong coupling, thus more accurately reflecting the actual instability characteristics of the multi-feed system.

[0056] Through the aforementioned mapping and joint constraint mechanism, the description of system-level operational restricted zones achieves the transformation from local indicators to global risks.

[0057] Preferably, the system-level restricted area description is updated in real time according to the changing trend of transient safety indicators of each converter station, so that the restricted area boundary can adaptively shrink or expand as the system transient response speed and coupling state change.

[0058] The system-level no-entry zone description is not static but updated in real time based on the changing trends of transient safety indicators at each converter station. This update mechanism allows the no-entry zone to dynamically reflect the current operating characteristics of the system. Specifically, when transient safety indicators show increased system disturbances or faster response speeds—for example, when indicator values ​​deteriorate rapidly—the update process promptly adjusts the boundary position and shape of the no-entry zone. By tracking the changing trends of indicators in real time, such as the rate of increase or decrease, the system can predict the evolution direction of potential risks, thereby correcting the no-entry zone in advance to ensure that it always remains consistent with the actual commutation instability risk.

[0059] The adaptive contraction or expansion of the forbidden zone boundary is the core manifestation of this update mechanism. When the system's transient response is slow and coupling is weak, it indicates that disturbance propagation is slow and the overall system margin is large. In this case, the forbidden zone boundary will adaptively expand, forming a relatively relaxed safe operating area. This allows the joint control units to adjust over a wider range without prematurely triggering conservative constraints. Conversely, when the transient response is faster or coupling is stronger, such as when the voltage interaction between multiple stations intensifies, disturbances may spread rapidly, leading to a commutation failure chain reaction. In this case, the forbidden zone boundary will adaptively contract, reducing the range of the safe operating area. This contraction forces the control units to adopt more cautious adjustment strategies earlier, avoiding the operating state from approaching the instability threshold.

[0060] Through the aforementioned real-time update and adaptive adjustment mechanisms, the system-level operational restricted zone description significantly improves the adaptability and robustness of multi-terminal HVDC transmission systems.

[0061] While generating a system-level operational restricted zone description, each joint control unit further formulates a cooperative safety constraint. This constraint is a quantified limit value derived from the restricted zone boundary and the current system state, used to guide the subsequent adjustment behavior of each joint control unit. Specifically, the cooperative safety constraint assesses in real time the distance between the current operating point and the restricted zone boundary, and accordingly imposes restrictions on the adjustment amplitude and direction of adaptive reactors or on-load tap changers. Its core purpose is to prevent local adjustment actions at any converter station from pushing the entire system towards commutation instability. For example, when local adjustment may worsen the transient safety indicators of adjacent stations, the constraint will force a reduction in adjustment intensity or a change in adjustment direction, thereby achieving system-level safety coordination.

[0062] The following describes step 103, namely "determining security conditions based on the relative positional relationship between the cooperative security constraint quantity and the system-level operational restricted area description," in detail with reference to an embodiment.

[0063] This step quantifies the relationship between the current system operating state and the commutation instability risk zone to determine whether to continue using rapid continuous adjustment or to switch to more discrete adjustment. The cooperative safety constraint is essentially a quantified value representing the current overall operating state, collaboratively generated by the joint control units based on exchanged information. The system-level no-entry zone description defines the high-risk instability areas in the state space that are not permitted to be entered. The assessment of their relative positions provides a clear basis for the selection of control strategies.

[0064] Specifically, the relative positional relationship mainly examines the distance and direction of the system operating point corresponding to the cooperative safety constraint from the boundary of the restricted area. When the operating point is located outside the restricted area and far from the boundary, it indicates that the overall commutation safety margin of the system is sufficient. At this time, the safety condition is deemed met, and disturbances can continue to be addressed solely through continuous adjustment of the adaptive reactor. This approach fully utilizes the advantages of continuous adjustment—fast response, smooth operation, and no impact—avoiding unnecessary on-load tap changer actions. Conversely, when the operating point gradually approaches the boundary of the restricted area or is already at a critical position, or even shows a tendency to enter the restricted area, the safety condition is no longer met. The control unit will immediately trigger the on-load tap changer to perform tap position switching, thereby rapidly changing the equivalent voltage structure of the converter station and fundamentally increasing the distance between the operating point and the instability region.

[0065] As an implementable approach, determining the safety conditions based on the relative positional relationship between the cooperative safety constraints and the system-level operational restricted zone description includes: constructing a multi-dimensional safety determination space characterizing the critical boundary of system commutation instability based on the system-level operational restricted zone description, wherein the multi-dimensional safety determination space uses the transient safety index and its changing trend as coordinate axes; mapping the cooperative safety constraints formed by the joint control units to the multi-dimensional safety determination space to obtain the corresponding system operating state points; and dynamically generating safety determination criteria to characterize whether the system operating state allows for continued continuous adjustment based on the spatial positional relationship between the system operating state points and the critical boundary of commutation instability.

[0066] Specifically, firstly, based on the generated system-level operational restricted zone description, a multi-dimensional safety decision space is constructed. This space uses the transient safety indicators and their changing trends of each converter station as coordinate axes, forming a high-dimensional geometric framework. The transient safety indicators reflect the static level of the current commutation safety state, while their changing trends capture the dynamic evolution rate of the indicators, such as the rate of increase or decrease. For example, for a system with several converter stations, the space has a corresponding number of dimensions; half of the dimensions correspond to the current indicator value of each station, and the other half corresponds to the rate of change of each indicator over a recent period. The changing trend is obtained by comparing the difference in indicator values ​​at the most recent sampling times. The system-level operational restricted zone description is represented as a boundary surface in this space, with one side being the safe zone and the other side being the unstable restricted zone. The boundary information of this space is stored in the controller memory in the form of numerical tables or functions.

[0067] Next, the collaborative safety constraints formed by the joint control units are mapped onto this multi-dimensional safety decision space to obtain the corresponding system operating state point. The collaborative safety constraints themselves already contain the weighted fusion of indicator and trend information from all stations; therefore, mapping directly maps this information to the coordinate axes of the space, resulting in a specific location point. This point's location represents the current operating state of the entire system. The collaborative safety constraints are a comprehensive quantitative value that integrates multi-station indicators and coupling effects. After mapping transformation, it is converted into a specific point location in the multi-dimensional space. This mapping process ensures that the constraint information generated by distributed collaboration can seamlessly connect with the unified decision space, making the overall system operating state intuitively visible. The location of the operating state point directly reflects the current system's distance from the commutation instability criticality and its trajectory trend, providing precise geometric basis for subsequent decisions.

[0068] Finally, a safety judgment criterion is dynamically generated based on the spatial positional relationship between the system's operating state point and the critical boundary of commutation instability. This criterion is not a fixed threshold but is adjusted in real time according to the relative position of the point and the boundary. For example, when the operating state point is located inside the safe zone and far from the boundary, and the trend of change points towards a safer direction, the judgment criterion allows continued continuous adjustment; when the point approaches the boundary or has a tendency to cross the boundary, the criterion immediately switches to unsafe, prohibiting further continuous adjustment and triggering discrete actions. Specifically, the distance from the state point to the boundary surface is calculated, as well as whether the current movement direction of the state point is moving towards the boundary surface. If the state point is on the safe side, far from the boundary surface, and the movement direction is away from the boundary surface, then the judgment criterion outputs that continued continuous adjustment is allowed; if the state point is already very close to the boundary surface, or is moving towards the boundary surface, then the judgment criterion immediately outputs that continued continuous adjustment is not allowed, and the on-load tap changer action must be triggered. This judgment criterion is sent directly to the local controller for execution in the form of a simple switching signal. This dynamic generation mechanism fully considers spatial geometric characteristics and dynamic trends, ensuring that the judgment criterion is always adapted to the current system risk level.

[0069] This technology enables adaptive switching of control strategies through dynamic safety condition determination based on relative positional relationships. Compared to traditional fixed threshold determination methods, it more fully considers the geometric characteristics of system-level restricted zones and multi-feed coupling effects. It maximizes the priority use of continuous regulation when safety margins are sufficient, and promptly activates discrete regulation as a backup when risks are imminent. This hierarchical decision-making mechanism ensures rapid suppression of transient disturbances and prevents the system from sliding into commutation instability restricted zones, thereby significantly improving the transient safety, control flexibility, and equipment operational reliability of multi-terminal HVDC transmission systems.

[0070] The following describes in detail step 104 above, namely, "When the cooperative safety constraint meets the safety conditions, the AC side voltage and current are rapidly adjusted by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range; when the cooperative safety constraint does not meet the safety conditions, the on-load tap changer is triggered to perform tap position switching to change the equivalent voltage regulation structure of the converter station, and the adjustment range of the adaptive reactor is redefined after the tap position switching."

[0071] When the cooperative safety constraints meet the safety conditions, this technical feature is implemented by only initiating continuous adjustment of the adaptive reactor without operating the on-load tap changer. The specific operation process is as follows: The joint control unit first confirms that the current system operating state is within the safe region of the multi-dimensional safety judgment space and is far from the instability boundary. At this time, the controller directly issues a continuous adjustment command to the adaptive reactor. The adaptive reactor typically adopts a magnetically controlled or thyristor-controlled structure, capable of smoothly changing the equivalent reactance value within milliseconds. The adjustment direction and magnitude are determined based on locally measured real-time AC side voltage deviation and current changes. For example, when the voltage decreases, the reactance value is reduced to increase reactive power support; when the voltage increases, the reactance value is increased to absorb reactive power. Through this rapid continuous adjustment, the AC side voltage and current are corrected in a timely manner, transient overcurrents are effectively suppressed, and the firing angle is maintained within the preset allowable operating range, avoiding interference to the commutation process.

[0072] As an implementable approach, the AC side voltage and current are rapidly adjusted by continuously regulating the reactance value of an adaptive reactor. This includes: determining the continuous adjustment direction and amplitude of the adaptive reactor based on locally measured AC side voltage deviation, current change rate, and the changing trend of the transient safety index, without triggering on-load tap changer switching; dynamically limiting the maximum adjustment rate and instantaneous adjustment range of the adaptive reactor according to the relative distance between the cooperative safety constraint and the system-level operating restricted area description; and during continuous adjustment, monitoring the changes in the firing angle and arc extinguishing angle in real time, and adaptively converging the reactance adjustment amplitude when the firing angle is detected to be close to the allowable operating boundary.

[0073] The specific implementation process first determines the adjustment direction and magnitude based on local measurement information. The joint control unit collects in real time the deviation between the actual voltage value and the reference value on the AC side of the converter station, the rate of change of current, and the changing trend of the previously calculated transient safety index. This information is directly input into the controller, which makes judgments according to preset adjustment rules. For example, when the voltage deviation shows a decrease and the rate of change of current increases, the controller decides to reduce the reactance value of the adaptive reactor to provide more reactive power support; conversely, it increases the reactance value to absorb reactive power. The adjustment magnitude is determined proportionally to the magnitude of the deviation and the speed of the trend; the larger the deviation or the faster the trend, the larger the initial magnitude, thereby achieving the purpose of quickly correcting the AC side voltage and current.

[0074] After determining the initial adjustment direction and magnitude, the controller further dynamically limits the maximum adjustment rate and instantaneous adjustment range of the adaptive reactor based on the relative distance between the cooperative safety constraint and the system-level no-entry zone description. In practice, the controller calculates the distance from the current system operating state point to the no-entry zone boundary in real time. If the distance is large, a higher adjustment rate and a wider instantaneous range are allowed, enabling the reactor to adjust rapidly and significantly; if the distance gradually decreases, the maximum allowable rate is gradually reduced and the upper limit of the instantaneous range is narrowed. This dynamic limitation is achieved through a proportional coefficient that smoothly decreases as the distance decreases, thereby ensuring that the adjustment behavior does not push the system operating state into the no-entry zone.

[0075] Throughout the continuous adjustment process, the joint control unit continuously monitors the changes in the firing angle and arc-extinguishing angle in real time. Once the firing angle is detected to be approaching its permissible operating boundary, such as reaching more than 90% of the preset upper limit, the controller immediately executes an adaptive convergence action. Specifically, this involves gradually reducing the reactance adjustment range, and even fine-tuning in the reverse direction if necessary, so that the firing angle and arc-extinguishing angle quickly return to the center of the safe range. This convergence mechanism is achieved through a monitoring feedback loop, where the step size of the adjustment command automatically decreases as the firing angle approaches the boundary until the indicators stabilize.

[0076] When the coordinated safety constraints fail to meet the safety conditions, meaning the system operating point is approaching or trending towards the instability boundary, the joint control unit immediately triggers the on-load tap changer to perform tap position switching. Specifically, the controller sends a switching command to the on-load tap changer drive unit. Under load conditions, the on-load tap changer rapidly changes the transformer ratio by selecting different transformer taps. This action directly alters the equivalent voltage level on the AC side of the converter station, thereby structurally adjusting the voltage regulation capability and quickly moving the system operating point away from the instability boundary. Tap position switching is typically completed within a few cycles. A brief transition process may occur during switching, but pre-designed switching logic ensures that no additional disturbances are caused.

[0077] After the on-load tap changer completes the tap position switching, the joint control unit immediately redefines the adjustment range of the adaptive reactor. Specifically, it acquires the equivalent AC side voltage and equivalent impedance parameters of the converter station after the on-load tap changer completes the tap position switching; based on the equivalent AC side voltage and equivalent impedance parameters, it updates the equivalent reactance adjustment range of the adaptive reactor so that the adjustment range meets the operating constraints of the firing angle and the arc extinguishing angle; and uses the updated equivalent reactance adjustment range as the allowable adjustment boundary in the subsequent continuous adjustment process.

[0078] The controller first reads the new transformer turns ratio after the switch and recalculates the equivalent AC side voltage and equivalent impedance parameters of the converter station. Then, based on these new parameters, it updates the upper and lower limits of the allowable reactance value of the adaptive reactor, ensuring that its adjustment range always remains within the range that satisfies the firing angle and arc-extinguishing angle constraints. Finally, the updated range is used as the boundary constraint for subsequent continuous adjustment. This re-limiting process ensures that the adjustment behavior of the adaptive reactor remains safe and effective under the new tap position, avoiding over-adjustment or under-adjustment.

[0079] The entire technical feature is implemented in real time in the processor of the joint control unit through the hierarchical mechanism of prioritizing continuous adjustment, discrete switching when necessary, and range resetting after switching, thereby achieving rapid response to transient disturbances and system-level safety protection.

[0080] The methods provided in this application can be applied to various scenarios, including but not limited to: First, in large-scale new energy base transmission systems, when a sudden fault occurs on the AC side causing a voltage dip, this method can quickly suppress the risk of multi-station commutation failure through distributed collaborative control, prioritize the continuous adjustment of adaptive reactors to maintain system stability, and only adjust on-load tap changers when necessary to avoid cascading faults causing large-scale power outages. Second, in urban multi-infeed DC receiving scenarios, such as the dense coupling of multiple DC landing points in East China, this method can effectively cope with transient overcurrents caused by load fluctuations or short-circuit faults, and prevent local regulation from amplifying coupling effects through system-level restricted areas, ensuring reliable power supply to the urban power grid. Finally, in offshore wind power flexible DC collection and transmission systems, this method can adapt to the space constraints and communication conditions of offshore platforms, realize low-latency index exchange and collaborative decision-making between adjacent converter stations, improve the ability to resist lightning or typhoon disturbances, and ensure the safety of long-distance power transmission.

[0081] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0082] According to another embodiment, a coordinated control device for on-load tap change and adaptive reactance of a converter voltage regulator is provided. Figure 2 shows a schematic block diagram of the coordinated control device for on-load tap change and adaptive reactance of the converter voltage regulator according to one embodiment. As shown in Figure 2, the device 200 includes:

[0083] The transient safety index acquisition unit 201 is configured to combine the on-load tap changer of the converter and the adaptive reactor into a joint control unit in each converter station of the multi-terminal high-voltage direct current transmission system, and acquire the transient safety index characterizing the commutation safety status in real time based on local measurement information of each joint control unit.

[0084] The restricted area description generation unit 202 is configured to exchange the transient safety indicators between the joint control units of adjacent converter stations, and based on the exchanged transient safety indicators and the electrical coupling relationship of each converter station in the multi-infeed DC system, collaboratively generate a system-level operational restricted area description to characterize the commutation instability state, and form a collaborative safety constraint quantity. The collaborative safety constraint quantity is used to restrict the adjustment behavior of each joint control unit to prevent local adjustment from causing the system operating state to enter the operational restricted area.

[0085] The security condition determination unit 203 is configured to determine security conditions based on the relative positional relationship between the cooperative security constraint quantity and the system-level operational restricted area description.

[0086] The cooperative control execution unit 204 is configured to, when the cooperative safety constraint quantity meets the safety conditions, rapidly adjust the AC side voltage and current by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range; when the cooperative safety constraint quantity does not meet the safety conditions, trigger the on-load tap changer to perform tap position switching to change the equivalent voltage regulation structure of the converter station, and redefine the adjustment range of the adaptive reactor after tap position switching.

[0087] As an implementable approach, the restricted area description generation unit 202 can be configured such that: the system-level operational restricted area description maps the transient safety indicators of each converter station to a unified transient operating state space, and jointly limits the regions corresponding to commutation instability states in the transient operating state space based on the electrical coupling strength between converter stations in a multi-infeed DC system.

[0088] As an implementable approach, the restricted area description generation unit 202 can be configured such that the system-level operational restricted area description is updated in real time according to the changing trends of transient safety indicators of each converter station, so that the restricted area boundary can adaptively shrink or expand with changes in system transient response speed and coupling state.

[0089] As an implementable approach, the restricted area description generation unit 202, when jointly defining the region corresponding to the commutation instability state in the transient operating state space based on the electrical coupling strength between converter stations in a multi-infeed DC system, can be configured as follows: acquiring electrical coupling parameters between each converter station in the multi-infeed DC system, the electrical coupling parameters including at least equivalent AC impedance, short-circuit ratio, or power mutual influence coefficient; determining the influence weight of the transient safety index of each converter station on the commutation stability of the system according to the electrical coupling parameters; mapping the transient safety index of each converter station to the transient operating state space according to the influence weight; and jointly superimposing the commutation instability criteria of multiple converter stations in the transient operating state space to construct a system-level commutation instability region boundary reflecting the multi-infeed coupling effect.

[0090] As an implementable approach, the safety condition determination unit 203, when determining safety conditions based on the relative positional relationship between the cooperative safety constraint quantity and the system-level operational restricted zone description, can be configured to: construct a multi-dimensional safety determination space characterizing the critical boundary of system commutation instability based on the system-level operational restricted zone description, wherein the multi-dimensional safety determination space uses the transient safety index and its changing trend as coordinate axes; map the cooperative safety constraint quantity formed by the joint control units to the multi-dimensional safety determination space to obtain the corresponding system operating state point; and dynamically generate a safety determination criterion characterizing whether the system operating state allows for continued continuous adjustment based on the spatial positional relationship between the system operating state point and the critical boundary of commutation instability.

[0091] As an implementable approach, the cooperative control execution unit 204, when rapidly adjusting the AC side voltage and current by continuously adjusting the reactance value of the adaptive reactor, can be configured to: determine the continuous adjustment direction and adjustment amplitude of the adaptive reactor based on locally measured AC side voltage deviation, current change rate, and the changing trend of the transient safety index, without triggering on-load tap changer switching; dynamically limit the maximum adjustment rate and instantaneous adjustment range of the adaptive reactor according to the relative distance between the cooperative safety constraint and the system-level operating restricted area description; and during continuous adjustment, monitor the changes in the firing angle and arc extinguishing angle in real time, and adaptively converge the reactance adjustment amplitude when the firing angle is detected to be close to the allowable operating boundary.

[0092] As an implementable approach, when the cooperative control execution unit 204 redefines the adjustment range of the adaptive reactor after a gear shift, it can be configured to: acquire the equivalent AC side voltage and equivalent impedance parameters of the converter station after the on-load tap changer completes the gear shift; update the equivalent reactance adjustment range of the adaptive reactor based on the equivalent AC side voltage and equivalent impedance parameters, so that the adjustment range meets the operating constraints of the firing angle and the arc extinguishing angle; and use the updated equivalent reactance adjustment range as the allowable adjustment boundary in the subsequent continuous adjustment process.

[0093] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0094] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0095] In addition, embodiments of this application also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method described in any of the foregoing method embodiments.

[0096] And an electronic device comprising: one or more processors; and a memory associated with the one or more processors, the memory being used to store program instructions that, when read and executed by the one or more processors, perform the steps of the method described in any of the foregoing method embodiments.

[0097] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method described in any of the foregoing method embodiments.

[0098] Figure 3 illustrates the architecture of an electronic device, which may include a processor 310, a video display adapter 311, a disk drive 312, an input / output interface 313, a network interface 314, and a memory 320. The processor 310, video display adapter 311, disk drive 312, input / output interface 313, network interface 314, and memory 320 can communicate with each other via a communication bus 330.

[0099] The processor 310 can be implemented using a general-purpose CPU, microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits to execute relevant programs in order to implement the technical solution provided in this application.

[0100] The memory 320 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 320 can store the operating system 321 for controlling the operation of the electronic device 300, and the basic input / output system (BIOS) 322 for controlling the low-level operations of the electronic device 300. Additionally, it can store a web browser 323, a data storage management system 324, and a coordinated control device 325 for the on-load tap changer and adaptive reactor of the converter voltage regulator, etc. The aforementioned coordinated control device 325 for the on-load tap changer and adaptive reactor of the converter voltage regulator can be the application program that specifically implements the aforementioned steps in this embodiment. In summary, when implementing the technical solution provided in this application through software or firmware, the relevant program code is stored in the memory 320 and executed by the processor 310.

[0101] Input / output interface 313 is used to connect input / output modules to realize information input and output. Input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touch screens, microphones, various sensors, etc., and output devices may include displays, speakers, vibrators, indicator lights, etc.

[0102] Network interface 314 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0103] Bus 330 includes a pathway for transmitting information between various components of the device, such as processor 310, video display adapter 311, disk drive 312, input / output interface 313, network interface 314, and memory 320.

[0104] It should be noted that although the above-described device only shows the processor 310, video display adapter 311, disk drive 312, input / output interface 313, network interface 314, memory 320, bus 330, etc., in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the solution of this application, and does not necessarily include all the components shown in the figures.

[0105] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer program product. This computer program product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0106] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for coordinated control of on-load tap change and adaptive reactance of a converter voltage regulator, characterized in that, The method includes: in each converter station of a multi-terminal high-voltage direct current transmission system, the on-load tap changer of the converter voltage regulator and the adaptive reactor constitute a joint control unit; each joint control unit calculates transient safety indicators characterizing the commutation safety state in real time based on local measurement information; the transient safety indicators between the joint control units of adjacent converter stations are exchanged; and based on the exchanged transient safety indicators and combined with the electrical coupling relationship between each converter station in the multi-infeed DC system, a system-level operation restricted zone description characterizing the commutation instability state is collaboratively generated, and a collaborative safety constraint quantity is formed. The collaborative safety constraint quantity is used to limit the adjustment behavior of each joint control unit to prevent local adjustment from causing the system operating state to enter the operation restricted zone; the system-level operation restricted zone description maps the transient safety indicators of each converter station to a unified transient operating state space, and based on the electrical coupling strength between converter stations in the multi-infeed DC system, jointly limits the region corresponding to the commutation instability state in the transient operating state space; the collaborative safety constraint quantity is based on the restricted zone boundary and the current system state. The derived quantitative limit values ​​are used to guide the subsequent adjustment behavior of each joint control unit. Based on the system-level no-entry zone description, a multi-dimensional safety judgment space characterizing the critical boundary of system commutation instability is constructed, with the transient safety index and its changing trend as coordinate axes. The collaborative safety constraint quantity formed by each joint control unit is mapped to the multi-dimensional safety judgment space to obtain the corresponding system operating state point. According to the spatial positional relationship between the system operating state point and the critical boundary of commutation instability, a safety judgment criterion for characterizing whether the system operating state allows for continued continuous adjustment is dynamically generated. When the collaborative safety constraint quantity meets the safety conditions, the AC side voltage and current are rapidly adjusted only by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range. When the collaborative safety constraint quantity does not meet the safety conditions, the on-load tap changer is triggered to perform a range switching to change the equivalent voltage regulation structure of the converter station, and the adjustment range of the adaptive reactor is redefined after the range switching.

2. The collaborative control method according to claim 1, characterized in that, The method further includes: the system-level operational restricted zone description is updated in real time according to the changing trend of transient safety indicators of each converter station, so that the restricted zone boundary can adaptively shrink or expand with the changes in system transient response speed and coupling state.

3. The collaborative control method according to claim 1, characterized in that, Based on the electrical coupling strength between converter stations in a multi-infeed DC system, the region corresponding to the commutation instability state in the transient operating state space is jointly defined, including: obtaining electrical coupling parameters between each converter station in the multi-infeed DC system, wherein the electrical coupling parameters include at least equivalent AC impedance, short-circuit ratio, or power mutual influence coefficient; determining the influence weight of the transient safety index of each converter station on the commutation stability of the system according to the electrical coupling parameters; mapping the transient safety index of each converter station to the transient operating state space according to the influence weight; and jointly superimposing the commutation instability criteria of multiple converter stations in the transient operating state space to construct a system-level commutation instability region boundary reflecting the multi-infeed coupling effect.

4. The collaborative control method according to claim 1, characterized in that, Rapidly regulating AC side voltage and current by continuously adjusting the reactance value of an adaptive reactor includes: determining the continuous adjustment direction and amplitude of the adaptive reactor based on locally measured AC side voltage deviation, current change rate, and the changing trend of the transient safety index, without triggering on-load tap changer switching; dynamically limiting the maximum adjustment rate and instantaneous adjustment range of the adaptive reactor according to the relative distance between the cooperative safety constraint and the system-level operating restricted area description; and monitoring the changes in the firing angle and arc extinguishing angle in real time during continuous adjustment, and adjusting the adaptive convergent reactor amplitude when the firing angle is detected to be close to the allowable operating boundary.

5. The collaborative control method according to claim 1, characterized in that, After the tap changer switches, the adjustment range of the adaptive reactor is redefined, including: obtaining the equivalent AC side voltage and equivalent impedance parameters of the converter station after the on-load tap changer completes the tap changer switch; updating the equivalent reactance adjustment range of the adaptive reactor based on the equivalent AC side voltage and equivalent impedance parameters, so that the adjustment range meets the operating constraints of the firing angle and the arc extinguishing angle; and using the updated equivalent reactance adjustment range as the allowable adjustment boundary in the subsequent continuous adjustment process.

6. A coordinated control device for on-load tap change and adaptive reactance of a converter voltage regulator, characterized in that, The device includes: a transient safety index acquisition unit, configured to, in each converter station of a multi-terminal high-voltage direct current transmission system, form a joint control unit with the on-load tap changer of the converter voltage regulator and the adaptive reactor, and acquire transient safety indices characterizing the commutation safety status in real time based on local measurement information from each joint control unit; and a restricted area description generation unit, configured to exchange the transient safety indices between the joint control units of adjacent converter stations, and, based on the exchanged transient safety indices and combined with the electrical coupling relationship of each converter station in the multi-infeed DC system, collaboratively generate a description of commutation instability. The system-level operational restricted zone is described, and a cooperative safety constraint is formed. This cooperative safety constraint restricts the adjustment behavior of each joint control unit, preventing local adjustments from causing the system operating state to enter the restricted zone. The system-level operational restricted zone description maps the transient safety indicators of each converter station to a unified transient operating state space, and jointly limits the regions corresponding to commutation instability states in the transient operating state space based on the electrical coupling strength between converter stations in a multi-infeed DC system. The cooperative safety constraint is based on the restricted zone boundary and the current system state. The jointly derived quantitative limit value is used to guide the subsequent adjustment behavior of each joint control unit. The safety condition determination unit is configured to construct a multi-dimensional safety judgment space characterizing the critical boundary of commutation instability of the system based on the system-level operation forbidden zone description. The multi-dimensional safety judgment space uses the transient safety index and its changing trend as coordinate axes. The collaborative safety constraint quantity formed by each joint control unit is mapped to the multi-dimensional safety judgment space to obtain the corresponding system operating state point. According to the spatial position relationship of the system operating state point relative to the critical boundary of commutation instability, a safety judgment criterion for characterizing whether the system operating state allows for continued continuous adjustment is dynamically generated. The collaborative control execution unit is configured to, when the collaborative safety constraint quantity meets the safety condition, quickly adjust the AC side voltage and current by continuously adjusting the reactance value of the adaptive reactor to suppress transient overcurrent and maintain the firing angle within the allowable range. When the collaborative safety constraint quantity does not meet the safety condition, the on-load tap changer is triggered to perform a tap position switch to change the equivalent voltage regulation structure of the converter station and redefine the adjustment range of the adaptive reactor after the tap position switch.

7. An electronic device, characterized in that, include: One or more processors; And a memory associated with the one or more processors, the memory being used to store program instructions that, when read and executed by the one or more processors, perform the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method according to any one of claims 1 to 5.

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