Load transfer control method and device for ac-dc hybrid distribution network and electronic equipment

Abstract

The application discloses a load transfer control method and device for an AC-DC hybrid power distribution network and electronic equipment. The method comprises the following steps: acquiring the current operation state of a plurality of converter stations in the AC-DC hybrid power distribution network; determining the load transfer target function and the load transfer constraint condition corresponding to the AC-DC hybrid power distribution network according to the current operation state; performing power flow calculation on the AC-DC hybrid power distribution network based on the load transfer constraint condition and a pre-constructed load transfer and system reconstruction model to obtain a power flow calculation result; calculating the target function value corresponding to the load transfer target function based on the power flow calculation result; and determining the load transfer control result of the AC-DC hybrid power distribution network according to the target function value. The application solves the technical problems of low control efficiency and inaccurate control in the prior art.

Description

Technical Field

[0001] This invention relates to the field of power grid load transfer control technology, and more specifically, to a load transfer control method, device, and electronic equipment for an AC / DC hybrid distribution network. Background Technology

[0002] Currently, research on load transfer control in AC / DC distribution networks mainly focuses on load transfer and reconfiguration within the AC power grid itself. Typically, sectionalizing switches and tie switches are used to segment feeders and connect them appropriately to achieve a ring network structure and open-loop operation. The segmentation level and the number of ties should be determined based on factors such as the number and installation location of distribution transformers, the nature of power users, the length of overhead lines, and the surrounding environment. Furthermore, the location of the line segmentation points should be adjusted accordingly with changes in the distribution network and load transfer. However, simply changing the switching combinations to improve the distribution network's operational level results in low load transfer control efficiency and poor control accuracy and real-time performance.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This invention provides a load transfer control method, apparatus, and electronic device for AC / DC hybrid distribution networks, to at least solve the technical problems of low control efficiency and inaccurate control in existing load transfer control methods.

[0005] According to one aspect of the present invention, a load transfer control method for an AC / DC hybrid distribution network is provided, comprising: acquiring the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: current operating parameters corresponding to the multiple converter stations respectively and the current switching status of tie switches included in the AC / DC hybrid distribution network; determining a load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status; performing power flow calculation on the AC / DC hybrid distribution network using a pre-constructed load transfer and system reconfiguration model based on the load transfer constraints, and obtaining power flow calculation results; calculating the objective function value corresponding to the load transfer objective function based on the power flow calculation results; and determining the load transfer control result of the AC / DC hybrid distribution network based on the objective function value.

[0006] Optionally, based on the aforementioned load transfer constraints, the above-mentioned load transfer and system reconfiguration model is used to perform power flow calculations on the aforementioned AC / DC hybrid distribution network to obtain power flow calculation results. This includes: based on the aforementioned load transfer constraints, using a grid adaptive direct search algorithm to perform outer-layer optimization calculations on the aforementioned load transfer and system reconfiguration model to obtain outer-layer optimization calculation results; based on the aforementioned load transfer constraints, using an alternating iterative algorithm to perform inner-layer power flow calculations on the aforementioned load transfer and system reconfiguration model to obtain inner-layer optimization calculation results; and determining the aforementioned power flow calculation results based on the aforementioned outer-layer optimization calculation results and the aforementioned inner-layer optimization calculation results.

[0007] Optionally, the determination of the load transfer control result of the AC / DC hybrid distribution network based on the objective function value includes: obtaining the comprehensive operation constraint index value in the load transfer constraint conditions; determining whether the multiple converter stations participate in load transfer optimization based on the comprehensive operation constraint index value; if the multiple converter stations participate in the load transfer optimization, then the load transfer control result is determined to include the target operating parameters corresponding to the multiple converter stations and the target switching state of the tie switches included in the AC / DC hybrid distribution network; if the multiple converter stations do not participate in the load transfer optimization, then the load transfer control result is determined to be the target switching state of the tie switches included.

[0008] Optionally, when a fault is detected in any converter station in the aforementioned AC / DC hybrid distribution network, the method further includes: obtaining the current operation control mode of the plurality of converter stations; determining an effective station set based on the current operation control mode; calculating the priority value corresponding to each converter station in the effective station set; and updating the current operation parameters corresponding to each of the plurality of converter stations based on the priority value.

[0009] Optionally, the above method further includes: determining the updated load transfer objective function and the updated load transfer constraints based on the updated current operating parameters; performing power flow calculations on the AC / DC hybrid distribution network based on the updated load transfer objective function and the updated load transfer constraints to obtain updated power flow calculation results; and determining the optimized operating parameters corresponding to the multiple converter stations based on the updated power flow calculation results.

[0010] Optionally, when determining the current operating control mode as a master-slave control mode, the method further includes: determining at least one new master station from the plurality of converter stations based on the priority values.

[0011] Optionally, the aforementioned AC / DC hybrid distribution network uses EtherCAT for real-time communication.

[0012] According to another aspect of the present invention, a load transfer control device for an AC / DC hybrid distribution network is also provided, comprising: an acquisition module, configured to acquire the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: current operating parameters corresponding to the multiple converter stations respectively and the current switching status of tie switches included in the AC / DC hybrid distribution network; a first determination module, configured to determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status; a first calculation module, configured to perform power flow calculation on the AC / DC hybrid distribution network based on the load transfer constraints using a pre-constructed load transfer and system reconfiguration model, and obtain power flow calculation results; a second calculation module, configured to calculate the objective function value corresponding to the load transfer objective function based on the power flow calculation results; and a second determination module, configured to determine the load transfer control result of the AC / DC hybrid distribution network based on the objective function value.

[0013] According to another aspect of the present invention, a non-volatile storage medium is also provided, the storage medium including a stored program, wherein, when the program is running, the device where the storage medium is located is controlled to execute any of the above-described load transfer control methods for AC / DC hybrid power distribution networks.

[0014] According to another aspect of the present invention, an electronic device is also provided, characterized in that it includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement any one of the above-described load transfer control methods for AC / DC hybrid distribution networks.

[0015] In this embodiment of the invention, a load transfer control method is adopted. This involves acquiring the current operating status of multiple converter stations in an AC / DC hybrid distribution network. The current operating status includes the current operating parameters corresponding to each converter station and the current switching status of the tie switches included in the AC / DC hybrid distribution network. Based on the current operating status, a load transfer objective function and load transfer constraints for the AC / DC hybrid distribution network are determined. Based on the load transfer constraints, a pre-constructed load transfer and system reconfiguration model is used to perform power flow calculations on the AC / DC hybrid distribution network, obtaining the power flow calculation results. Based on the power flow calculation results, the objective function value corresponding to the load transfer objective function is calculated. Based on the objective function value, the load transfer control result for the AC / DC hybrid distribution network is determined. This achieves the goal of load transfer control based on converter station parameter information and tie switch status information, thereby improving the control efficiency and accuracy of the AC / DC hybrid distribution network. This solves the technical problems of low control efficiency and inaccurate control in existing load transfer control methods. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0017] Figure 1 This is a flowchart of a load transfer control method for an AC / DC hybrid distribution network according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of an optional AC / DC hybrid power distribution network topology according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram illustrating the specific search process of an optional grid adaptive direct search algorithm according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of an optional power flow calculation process according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of another optional power flow calculation process according to an embodiment of the present invention;

[0022] Figure 6 This is a flowchart of an optional load transfer control method for a hybrid AC / DC distribution network according to an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of another optional AC / DC hybrid distribution network topology according to an embodiment of the present invention;

[0024] Figure 8 This is a schematic diagram of an optional AC / DC hybrid distribution network load transfer control system according to an embodiment of the present invention;

[0025] Figure 9 This is an optional priority value calculation flowchart according to an embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of another optional AC / DC hybrid distribution network load transfer control system according to an embodiment of the present invention;

[0027] Figure 11 This is a schematic diagram of an optional AC / DC system coordinated control and mode switching based on EtherCAT real-time Ethernet according to an embodiment of the present invention;

[0028] Figure 12 This is a schematic diagram of the structure of a load transfer control device for an AC / DC hybrid distribution network according to an embodiment of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] Currently, research on load transfer control in AC / DC distribution networks mainly focuses on two directions: load transfer control and uninterrupted load transfer control. In load transfer control, traditional distribution network load transfer and network reconfiguration primarily improve the network's operational level by changing the switching combinations of switches, effectively reducing system network losses and improving node voltage to enhance power quality. Distribution network transfer and reconfiguration include static and dynamic transfer reconfiguration. Static transfer reconfiguration is relatively mature, mainly optimizing the system at a specific time point. Its drawback is that it ignores actual conditions such as load changes and switch operation constraints. Dynamic transfer reconfiguration, on the other hand, needs to consider load changes over various time periods, making it more complex, but it is more practically significant for system scheduling and fault recovery. In uninterrupted load transfer control, when a fault occurs, the flexible DC interconnection device in the converter station can supply power to the disconnected area after the fault is cleared. This requires switching the control method of the flexible DC interconnection device to provide AC-side voltage / frequency support. To achieve uninterrupted power transfer control of AC loads under fault isolation conditions, during the control mode switching process, on the one hand, the station needs to coordinate control with other converter stations and quickly adjust the control modes of other converter stations; on the other hand, it also needs to cooperate quickly with protection devices and coordinate the control mode in real time according to the status of the circuit breaker in the fault area.

[0032] Based on the above problems, this embodiment of the invention provides a method embodiment for load transfer control of AC / DC hybrid distribution network. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] Figure 1 This is a flowchart of a load transfer control method for an AC / DC hybrid distribution network according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes the following steps:

[0034] Step S102: Obtain the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: the current operating parameters corresponding to the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network.

[0035] Step S104: Determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status.

[0036] Step S106: Based on the above load transfer constraints, the power flow calculation of the above AC / DC hybrid distribution network is performed using a pre-built load transfer and system reconfiguration model to obtain the power flow calculation results;

[0037] Step S108: Calculate the objective function value corresponding to the above load transfer objective function based on the above power flow calculation results;

[0038] Step S110: Determine the load transfer control result of the AC / DC hybrid distribution network based on the above objective function value.

[0039] Optionally, the above load transfer control results may include, but are not limited to, the target operating parameters corresponding to the above-mentioned multiple converter stations and the target switching status of the tie switches included in the above-mentioned AC / DC hybrid distribution network.

[0040] In this embodiment of the invention, a load transfer control method is adopted. This involves acquiring the current operating status of multiple converter stations in an AC / DC hybrid distribution network. The current operating status includes the current operating parameters corresponding to each converter station and the current switching status of the tie switches included in the AC / DC hybrid distribution network. Based on the current operating status, a load transfer objective function and load transfer constraints for the AC / DC hybrid distribution network are determined. Based on the load transfer constraints, a pre-constructed load transfer and system reconfiguration model is used to perform power flow calculations on the AC / DC hybrid distribution network, obtaining the power flow calculation results. Based on the power flow calculation results, the objective function value corresponding to the load transfer objective function is calculated. Based on the objective function value, the load transfer control result for the AC / DC hybrid distribution network is determined. This achieves the goal of load transfer control based on converter station parameter information and tie switch status information, thereby improving the control efficiency and accuracy of the AC / DC hybrid distribution network. This solves the technical problems of low control efficiency and inaccurate control in existing load transfer control methods.

[0041] Optionally, the above load transfer objective function can be understood as the objective function for load transfer and system operation status reconfiguration of AC / DC hybrid distribution network. The above objective function may include, but is not limited to: economic reconfiguration objective function, network loss minimization reconfiguration objective function, fault prevention reconfiguration objective function, and load factor balancing transfer objective function. Among them, the above fault prevention reconfiguration objective function includes: static safety margin index and power supply security index.

[0042] Optionally, for the above-mentioned economic restructuring objective function, the purpose of dynamic power transfer restructuring of AC / DC hybrid distribution networks includes maximizing overall operational economy, minimizing overall network losses, minimizing the number of system switching operations, etc. Here, the objective is to maximize the operating cost savings of the system within a certain period. The above-mentioned economic restructuring objective function can be, but is not limited to, the following:

[0043]

[0044] Among them, Ci For the electricity price during period i, To transfer the total power of the system before and after, C B,k For the operating cost of the interconnecting switch, x k,i x k,i-1 The connection switch is in operation.

[0045] Optionally, for the above objective function of minimizing network loss during reconfiguration, the dynamic power transfer reconfiguration of the AC / DC hybrid distribution network can be optimized with the objective function of minimizing the overall network loss of the system, as shown in the following expression:

[0046]

[0047] Where n represents the total number of branches in the power distribution network; k i Indicates the state of switch i, where 0 represents open and 1 represents closed; r i P represents the resistance of branch i; i Q i It refers to the active and reactive power flowing through branch i; U i It is the voltage at the end node of branch i.

[0048] Optionally, for the aforementioned fault-prevention reconfiguration objective function, current research on distribution network reconfiguration mainly focuses on economic reconfiguration and rapid power restoration. Economic reconfiguration generally studies the network structure that maximizes system operating economy or load balancing rate under a given load level. Rapid power restoration reconfiguration mainly studies control strategies for rapidly restoring power supply to loads in non-faulty power-loss areas under distribution network fault conditions. However, research on distribution networks under normal conditions generally focuses on security assessment and early warning stages. How to implement system reconfiguration strategies for specific early warning incidents under early warning conditions requires further research, especially since AC / DC distribution networks possess better power flow control capabilities. It should be noted that the objective function for fault-prevention reconfiguration still selects minimizing system operating costs or network losses, but it requires constraints from system static safety margin indicators and power supply security indicators.

[0049] Regarding the aforementioned static safety margin index, the static safety margin of a distribution network is the distance from the current operating point of the system to the static safety critical point, i.e., the distance from the load rate of each feeder to the critical maximum load rate. Although a positive value indicates that the system does not exceed its limits, considering the uncertainties of the distribution network, if this value is small, the system may enter an unsafe operating state when the load fluctuates. In this case, the system is in a warning operating state. The distribution network must maintain a sufficiently large static safety margin to ensure that the randomness of distribution network operation does not threaten its reliability. The static safety margin target can be expressed as follows:

[0050]

[0051] In the formula, F nmax and F nmax These represent the critical load capacity and actual load capacity of feeder n, respectively, and α represents the static safety margin index.

[0052] For the aforementioned power supply safety indicators, meeting the N-1 safety verification of each line segment is a sufficient condition for meeting the N-1 safety verification of the feeder. Therefore, the N-1 safety indicator of each line segment is used as the power supply safety indicator. When the system does not meet the N-1 safety verification of each line segment, although the current operating point can meet static safety and voltage and power flow indicators do not exceed limits, a partial load loss will occur when an N-1 fault occurs, and the current operating point will be in a warning operation state. Dispatchers need to improve power supply safety under N-1 faults by adjusting the operating mode and the load capacity of each feeder. The power supply safety indicator can be expressed as follows:

[0053] h PSR =min(max{CFM 1m CFM 2m …CFM nm …CFM Nm})≥β

[0054] In the formula, CFM nm Converse Feeder Margin Capacity (CFM) is the remaining capacity after subtracting the capacity of the reverse power supply path from the redundant capacity of the spare feeder. If CFM... nm >0 indicates that feeder n on the power supply path can transfer power to node m; otherwise, it indicates that feeder n does not have enough capacity to transfer power to node m.

[0055] Optionally, for the above load balancing transfer objective function, in an AC / DC hybrid distribution network, different areas of the AC grid are interconnected via flexible DC. Since the load rates of each AC grid are different, power exchange between different AC areas can be adjusted via flexible DC to transfer active power from AC grids with heavier load rates to AC grids with lower load rates, thereby improving the overall power supply capacity and security of the system. The load balancing transfer objective function selects the system power imbalance index h3 as the objective function:

[0056]

[0057] Among them, P ac_j P ac_jr P represents the actual power and rated power of the AC node. dc_j P dc_jr This refers to the actual power and rated power of the DC node.

[0058] Optionally, the aforementioned load transfer constraints can be understood as constraints on load transfer and system operation state reconfiguration in AC / DC hybrid distribution networks. These constraints may include, but are not limited to, AC constraints, DC constraints, converter station operation limitations, and comprehensive operation index constraints. Specifically, the aforementioned AC constraints may include, but are not limited to, AC system power balance constraints, AC node voltage constraints, AC branch power flow constraints, AC boundary limitations, and AC network topology constraints. The aforementioned DC constraints and comprehensive operation index constraints may include, but are not limited to, DC system power balance constraints, DC node voltage constraints, DC branch power flow constraints, and DC boundary limitations. The aforementioned comprehensive operation index constraints may include, but are not limited to, voltage offset constraints, system power imbalance constraints, static safety margin constraints, and power supply security index constraints.

[0059] Optionally, the power balance constraints of the AC system described above can be calculated using the following formula:

[0060]

[0061]

[0062] Among them, P gi Active power injected into the generator at node i; P ci Active power injected into the generator at node i; P vsclossi P represents the active power loss of the i-node of the VSC. di For the active power at the port of the flexible DC device; G ij B ij V represents the real and imaginary parts of the nodal admittance matrix elements; i V is the voltage at node i; j The voltage at node j; δ i δ is the phase angle of node i; j Q is the phase angle at node j; gi Reactive power injected into the generator at node i; Q di This refers to the reactive power at the port of the flexible DC device.

[0063] Optionally, the above AC node voltage constraint can be expressed as: Among them, V ac_n For AC node voltage, This is the lower limit of the AC node voltage. This represents the upper limit of the AC node voltage.

[0064] Optionally, the above AC branch power flow constraints can be expressed as: Among them, f ac_ ij represents the current flow of the AC branch. To be the lower limit of the current flow of the branch line, This is the upper limit of the current flow in the branch circuit.

[0065] Optionally, the above-mentioned communication boundary constraint can be expressed as: Among them, P ac_ i is a valuable contribution to the communication branch. The lower limit of the contribution to the exchange branch road, The upper limit of the contribution of the communication branch.

[0066] Optionally, the above-mentioned AC network topology constraints may, but are not limited to, ensuring that the AC / DC hybrid distribution network never experiences islanding and maintains a radial structure during the reconfiguration process.

[0067] Optionally, the power balance constraint of the above DC system can be expressed as: Among them, P dc_i The active power injected into node i of the DC network, P dcac_i P represents the active power of the DC-AC switching at node i. dcload_i The active power of the DC load at node i.

[0068] Optionally, the above DC node voltage constraint can be expressed as: Among them, V dc_m This is the DC node voltage. This is the lower limit of the DC node voltage. This represents the upper limit of the DC node voltage.

[0069] Optionally, the above DC branch power flow constraints can be expressed as: Among them, f dc_ij For DC branch power flow, This is the lower limit of the power flow in the DC branch. This is the upper limit of the power flow of the DC branch.

[0070] Optionally, the above DC boundary constraint can be expressed as: Among them, P dc_i Active power for DC branch, This is the lower limit of active power for the DC branch. This is the upper limit of active power for the DC branch.

[0071] Optionally, the above-mentioned converter station operation constraints can be expressed as:

[0072]

[0073]

[0074]

[0075] Among them, S c It is the converter station capacity; P cIt is the real-time active power of the converter station; Q c It is the real-time reactive power of the converter station; V c It is the converter station voltage; I c It is the converter station current; Q c It is the real-time reactive power of the converter station. Lower limit of reactive power of converter station upper limit of reactive power for converter stations; This is the upper limit of active power for the converter station.

[0076] Optionally, the above voltage offset constraint can be expressed as: Where h2 is the voltage offset; This is the lower limit of the voltage offset. This represents the upper limit of the voltage offset.

[0077] Optionally, the above system power imbalance constraint can be expressed as: Where h3 represents the system power imbalance; This represents the lower limit of system power imbalance. This represents the upper limit of the system power imbalance.

[0078] Optionally, the above static safety margin constraint can be expressed as: h SSR ≥α, where h SSR α represents the static safety margin index for calculation; α represents the limit value of the static safety margin index.

[0079] Optionally, the above power supply safety index constraints can be expressed as: h PSR ≥β, where h PSR β is the calculated power supply safety index, and β is the power supply safety index limit.

[0080] It should be noted that AC / DC hybrid distribution networks can flexibly control system power flow through converter stations, achieving load balancing among multiple feeders, optimizing the power supply capacity of the grid, and significantly improving the reliability and equipment utilization of the distribution network. The goal of load transfer and system operation state reconfiguration in AC / DC hybrid distribution networks is to achieve continuous and smooth load transfer between different AC regions, effectively reducing the operation of tie switches and the number of network reconfigurations. The control methods involve active / reactive power regulation of multi-terminal DC converter stations combined with discrete control of AC tie switches. Load transfer and system operation state reconfiguration need to consider system economy, power quality, and system reliability; therefore, suitable evaluation indicators need to be selected as the basis for further obtaining the above-mentioned load transfer objective function and load transfer constraints. For example, taking a three-terminal AC / DC hybrid distribution network as an example for analysis, the topology of the AC / DC hybrid distribution network is as follows: Figure 2As shown, three AC power grids in three different regions are interconnected through three converter stations. The evaluation indicators mentioned above may include, but are not limited to, network loss, voltage deviation, and system power imbalance.

[0081] Optionally, by using a normalization method to integrate the above evaluation indicators into a comprehensive performance index for distribution network operation, and by setting the standard deviation of the comprehensive performance index, the reconfiguration period of the AC / DC hybrid distribution network system can be divided.

[0082] Optionally, the above network loss can be calculated using the following formula:

[0083]

[0084] Where n represents the total number of branches in the power distribution network; k i Indicates the state of switch i, where 0 represents open and 1 represents closed; r i P represents the resistance of branch i; i Q i It refers to the active and reactive power flowing through branch i; U i It is the voltage at the end node of branch i.

[0085] Optionally, the voltage offset can be calculated using the following formula:

[0086]

[0087] Among them, U ac_j U ac_jr U represents the actual voltage and rated voltage of the AC node. dc_j U dc_jr This refers to the actual voltage and rated voltage of the DC node.

[0088] Optionally, the power imbalance of the above system can be calculated using the following formula:

[0089]

[0090] Among them, P ac_j P ac_jr P represents the actual power and rated power of the AC node. dc_j P dc_jr This refers to the actual power and rated power of the DC node.

[0091] In an optional embodiment, based on the aforementioned load transfer constraints, a pre-built load transfer and system reconfiguration model is used to perform power flow calculations on the aforementioned AC / DC hybrid distribution network to obtain power flow calculation results, including:

[0092] Based on the above load transfer constraints, the grid adaptive direct search algorithm is used to perform outer-layer optimization calculations on the above load transfer and system reconfiguration model to obtain the outer-layer optimization calculation results.

[0093] Based on the above load transfer constraints, an alternating iterative algorithm is used to perform inner-layer power flow calculations on the above load transfer and system reconfiguration model to obtain inner-layer optimization calculation results.

[0094] Based on the above outer layer optimization calculation results and the above inner layer optimization calculation results, the above power flow calculation results are determined.

[0095] It should be noted that due to the diverse types of equipment and complex operation and control methods within AC / DC hybrid distribution networks, the flexibility and controllability of VSC converter stations and the integration of renewable energy further complicate their operation and scheduling models. Furthermore, load transfer can be achieved through both converter station power control and AC tie switch operation, resulting in significant differences in the complexity of load transfer and operation state reconfiguration scheduling models for AC / DC distribution networks, thus leading to substantial differences in the selection of optimization algorithms. In the load transfer and system reconfiguration models of AC / DC hybrid distribution networks, AC / DC power flow calculations are required at each time point to verify whether the constraints are met. Therefore, an alternating iterative power flow calculation method is chosen to facilitate the use of intelligent solution algorithms for optimizing converter station power and AC tie switches.

[0096] Optionally, the Mesh Adaptive Direct Search (MADS) algorithm is used to perform outer-layer optimization calculations on the above load transfer and system reconfiguration model. The MADS algorithm extends direct search algorithms, allowing local search or direction filtering. Its optimization variables can be continuous, discrete, or binary, and the objective function and constraints can be nonlinear or "black box," making it convenient for solving nonlinear and multivariate optimal problems. The optimal power flow solution process for AC / DC hybrid distribution networks is an iterative process based on alternating global and local searches using the MADS algorithm. In the local search phase, a mesh adaptive direct search is used to converge to a local optimum. In the global search phase, a fully randomized Monte Carlo method is used. Each iteration calculates the function values ​​based on a finite number of test points and frame set points selected from the grid set. The specific MADS search process is as follows: Figure 3 As shown.

[0097] It should be noted that the MADS algorithm is a type of direct search algorithm that solves two fundamental problems in the iterative search process: poll size selection and poll direction selection. Its optimization variables can be continuous, discrete, or binary, and both the objective function and constraints can be nonlinear or "black box" in form. It supports the selection of the direction of optimization variables within a compact set of the constraint space, avoiding the tendency of traditional direct search methods to get trapped in local minima at the boundary, and can conveniently solve nonlinear and multivariate optimization problems. Its search process is as follows: Figure 4 As shown, during the MADS search process, it is first necessary to determine the initial search point x0 and the grid size parameter. and vote size parameter Based on this, the objective function values ​​of a finite number of points on the current set of grids are evaluated. A better point is searched on the current set of grids based on these objective function values. If no better point is found in the search step, a filtering Poll step is performed to evaluate the points on the filtered Poll set. If no better point is found again, the grid size parameter is reduced. and vote size parameters It then determines whether the current search results have converged. If the result is yes, the search optimization process ends; otherwise, it increases the grid size parameter. and vote size parameters Next search point x k+1 To establish a new network center, repeat the search operation described above.

[0098] Optionally, an alternating iterative algorithm is used to perform inner-layer power flow calculations on the aforementioned load transfer and system reconfiguration model. The inner-layer power flow calculation includes three sub-iterative processes: AC network iteration, DC network iteration, and substation solution iteration. The inner-layer power flow calculation includes DC power flow calculation processes and AC power flow calculation processes, such as... Figure 5 As shown, after performing AC power flow calculation and the settlement result converges, DC power flow calculation is started. The results of DC power flow calculation and AC power flow calculation are combined to determine whether the inner layer power flow calculation has converged. If the result is yes, the result is output directly. Otherwise, the relaxation node and the equivalent motor node of the converter station are updated, and the inner layer power flow calculation is restarted. The above steps are repeated until the maximum number of iterations is reached.

[0099] It should be noted that in the alternating iterative method, the AC power flow calculation result is used as the voltage value of the AC bus of the converter station in each iteration, while the DC power flow calculation result provides the equivalent active and reactive power of the converter station for the AC power flow calculation in the next iteration, and so on until convergence. Under this assumption, the DC power in the AC power flow calculation is a known constant, and the AC voltage in the DC power flow calculation is a known constant, thereby achieving decoupling of the AC and DC systems.

[0100] It should be noted that the AC / DC hybrid distribution network load transfer and system reconfiguration model adopts a two-layer structure for optimization calculation. The grid adaptive direct search algorithm MADS is used as the outer optimization driver for the AC / DC hybrid distribution network load transfer and system reconfiguration calculation, while the inner power flow calculation program adopts an alternating iterative calculation method, thereby improving the accuracy of the power flow calculation results.

[0101] As an optional embodiment, Figure 6 This is a flowchart of an optional load transfer control method for a hybrid AC / DC distribution network according to an embodiment of the present invention, such as... Figure 6 As shown, the method includes: acquiring and inputting the current operating status data of multiple converter stations in the AC / DC hybrid distribution network, and preprocessing the current operating status data, wherein the current operating status data includes: the current operating parameters corresponding to the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network; loading the load transfer optimization calculation main program, and determining the load transfer objective function, load transfer constraints, and test points corresponding to the AC / DC hybrid distribution network based on the current operating status data; performing power flow calculation on the AC / DC hybrid distribution network using a pre-constructed load transfer and system reconfiguration model based on the load transfer constraints, and obtaining the power flow calculation results, wherein the power flow calculation is an AC / DC hybrid power flow calculation; calculating the load transfer objective function value when the power flow calculation results converge; and drawing the current operating topology diagram of the AC / DC hybrid distribution network (e.g., ...) when the objective function value converges. Figure 7 As shown in Table 1 to Table 4), the load transfer control results of the above AC / DC hybrid distribution network are output.

[0102] Table 1

[0103]

[0104] Table 2

[0105]

[0106] Table 3

[0107]

[0108] Table 4

[0109]

[0110] In an optional embodiment, determining the load transfer control result of the AC / DC hybrid distribution network based on the objective function value includes:

[0111] Obtain the comprehensive operational constraint index value from the above load transfer constraints;

[0112] Based on the above comprehensive operational constraint index values, determine whether the above-mentioned converter stations should participate in load transfer optimization;

[0113] If the aforementioned multiple converter stations participate in the aforementioned load transfer optimization, then the aforementioned load transfer control results are determined to include the target operating parameters corresponding to the aforementioned multiple converter stations and the target switching status of the aforementioned interconnection switches in the aforementioned AC / DC hybrid distribution network.

[0114] If the aforementioned converter stations do not participate in the aforementioned load transfer optimization, then the aforementioned load transfer control result is determined to be the aforementioned target switch state of the interconnection switches included above.

[0115] Optionally, the aforementioned comprehensive operational constraint values ​​may include, but are not limited to, voltage offset, system power imbalance, static safety margin constraints, and power supply safety constraints. The aforementioned load transfer control results are used to indicate whether the converter participates in load transfer optimization.

[0116] It should be noted that in practical applications, different application scenarios may correspond to different load transfer control results. For example, in some cases, load transfer control may be achieved by adjusting the target switch state of the tie switch, while in other cases, the converter station operating parameters and the tie switch may need to be controlled together to achieve effective load transfer control. Therefore, the embodiments of the present invention determine the specific load transfer control result based on the comprehensive operation constraint index value of the AC / DC hybrid distribution network, thereby achieving the technical effect of continuous and smooth load transfer between different AC areas and effectively reducing the operation of the tie switch and the number of network reconfigurations.

[0117] As an optional embodiment, the load transfer control method provided in this invention can be applied to, for example... Figure 8 In the AC / DC hybrid distribution network load transfer control system shown, such as Figure 8As shown, the software modules corresponding to the load transfer and system operation status reconfiguration parts of this system mainly include functions such as operation status analysis, load transfer optimization, command output execution, and coordination with the dispatch automation module and distribution automation system. The operation status analysis function includes transfer path analysis, electrical islanding analysis, feeder load rate analysis, converter load rate analysis, converter active power regulation capability analysis, and converter reactive power regulation capability analysis; the data for the operation status analysis module is mainly obtained from the AC / DC operation control system. The load transfer optimization function calculates the system's static safety margin, power supply safety indicators, voltage deviation, and distribution transformer balance; then it predicts whether the converter station should participate in load transfer optimization, uses different optimization models to obtain the optimal transfer scheme, and outputs dispatch execution commands. The coordination functions between the dispatch automation system, distribution automation system, and AC / DC operation control system are as follows: the dispatch automation system sends substation bus voltage, feeder outgoing switch position, and substation electrical topology data to the AC / DC operation control system; the distribution automation system sends feeder switch remote signaling (switch position), feeder switch telemetry (UIPQ), feeder equipment parameters, and feeder equipment connection relationship data to the AC / DC operation control system; and the operation data of the multi-terminal flexible ring network equipment interacts with the AC / DC operation control system and the distribution automation system.

[0118] In an optional embodiment, when a fault is detected at any converter station in the aforementioned AC / DC hybrid distribution network, the method further includes:

[0119] Obtain the current operating control mode of the above-mentioned multiple converter stations;

[0120] The set of valid stations is determined based on the current operation control mode described above.

[0121] Calculate the priority value for each converter station in the above set of valid stations;

[0122] Update the current operating parameters of the aforementioned converter stations according to the aforementioned priority values.

[0123] Optionally, the above-mentioned current operating control mode may include, but is not limited to, master-slave control mode and droop control mode.

[0124] Optionally, obtaining the current operating control mode of the aforementioned multiple converter stations includes: the dispatching system of the AC / DC hybrid distribution network scanning all converter station control flag bits, where C1 represents the first converter station, C2 represents the second converter station, and so on, with Cn representing the nth converter station, and n being the total number of converter stations. The value range of the total number of converter stations n depends on the actual system, but is not less than 2. When the j-th converter station adopts a master-slave control mode or an AC droop control mode, the control flag bit F of the j-th converter station... Cj Set it to 1, i.e., FCj =1.

[0125] Optionally, the effective station set determined based on the current operation control mode includes: based on the scanned converter station operation control mode, setting the converter station control flag bit F among them. Cj Converter stations with a capacity not equal to 1 form an effective station set, and their respective static information is obtained, including the rated capacity S of the corresponding converter station. C1,rated S C2,rated ...S Cm,rated ; and dynamic operating power data, including the AC-side active power P of the corresponding converter station. C1 P C2 ...P Cm And the corresponding AC-side reactive power Q of the converter station C1 Q C2 ...Q Cm m represents the total number of valid stations, and its value range depends on the actual system status. The total number of valid stations m is not greater than the total number of converter stations n.

[0126] Optionally, calculate the priority weights for each converter station in the aforementioned set of effective stations, including: based on the constructed set of effective stations, calculate the weighted Euclidean distance d for each converter station in the set of effective stations. C1 d C2 ...d Cm The converter stations in the valid station set are assigned priority values ​​according to their numerical values. The converter station i with the largest weighted Euclidean distance value is assigned a priority value Pr. Ci Assign a priority value of 1 to converter station k, ranked second in weighted Euclidean distance, Pr. Ck Assign it to 2, and so on. The specific calculation process is as follows: Figure 9 As shown, the dispatching system of the AC / DC hybrid distribution network transmits the priority values ​​of each converter station in the effective station set to each converter station.

[0127] In an optional embodiment, the above method further includes:

[0128] Based on the updated current operating parameters, the updated load transfer objective function and updated load transfer constraints are determined.

[0129] Based on the updated load transfer objective function and the updated load transfer constraints, power flow calculations are performed on the AC / DC hybrid distribution network to obtain the updated power flow calculation results.

[0130] Based on the updated power flow calculation results, the optimized operating parameters for each of the aforementioned converter stations were determined.

[0131] Optionally, the optimized control parameters may include, but are not limited to, the optimized control mode and operating power command for each converter station.

[0132] It should be noted that after updating the above-mentioned current operating parameters, the converter station controller monitors the AC side voltage, DC side voltage, grid connection switch status, and other information of the corresponding converter station in real time. The converter station controller adopts safe power transfer operation control to jointly achieve uninterrupted and safe load transfer. The AC / DC hybrid distribution network dispatching system, based on the current optimization operation objectives, such as optimal economy and minimum network loss, combined with the operating constraints of each station and the system, such as line transmission power constraints and converter station power constraints, performs AC / DC hybrid distribution network optimized power flow calculations to generate F. Cj The optimized control mode and operating power command for each converter station with ! = 1 are then issued to each converter station.

[0133] In an optional embodiment, when determining the current operating control mode as a master-slave control mode, the method further includes:

[0134] At least one new master station is determined from the multiple converter stations mentioned above based on the aforementioned priority values.

[0135] It should be noted that when any converter station in an AC / DC hybrid distribution network (such as the AC side system of a converter station) fails, the operation control mode of the converter station is changed (for example, by changing the current operating parameters of the converter station to update the operation control mode), so that it operates in a constant voltage and constant frequency control mode, supporting the AC side voltage and frequency, and providing uninterrupted power supply to important loads. When a converter station controlling DC voltage performs uninterrupted power supply, adjustments are made according to the current control mode. Different operation control modes correspond to different adjustment strategies. For example, if it is a master-slave control mode, a new master station supporting the voltage needs to be selected, and calculations are used to ensure that the new master station is not overloaded after the power transfer. If it is a droop control mode, it is necessary to analyze whether the droop at both ends can maintain the stability of the DC voltage and calculate a new droop rate. At the same time, uninterrupted power transfer and protection work together to minimize time delay and ensure real-time performance.

[0136] As an optional embodiment, the load transfer control method provided in this invention can be applied to, for example... Figure 10 In the AC / DC hybrid distribution network load transfer control system shown, such as Figure 10As shown, when a short-circuit fault occurs in the AC side system of a converter station, the system switches the station's operation control mode to a constant voltage and frequency control mode (i.e., master-slave control mode) to support AC side voltage and frequency, providing uninterrupted power transfer capability to critical loads. The software modules corresponding to the uninterrupted power transfer part of this system mainly include effective station set analysis, priority weight calculation, and safe power transfer strategies, as well as coordination with three-terminal interconnection devices, dispatch automation, and distribution automation systems. Specifically, effective station set analysis is used to update the real-time operating data and control modes of each converter station and construct an effective station set. Priority weight calculation is used to calculate the power transfer priority weight of each converter station based on data such as converter station capacity and operating power. The safe power transfer strategy is used to switch from constant DC voltage control to constant voltage and constant frequency control when the converter station controlling the DC voltage provides uninterrupted power transfer. The new master station supporting the voltage is selected according to the priority value, and the new master station is guaranteed not to be overloaded through calculation. When the converter station controlling the constant power provides uninterrupted power transfer: the switch is made to constant voltage and constant frequency control, and the operating points of other stations are adjusted.

[0137] In one alternative embodiment, the aforementioned AC / DC hybrid power distribution network uses EtherCAT for real-time communication.

[0138] It should be noted that, in order to solve the real-time problem of multi-terminal DC network operation mode switching and protection coordination in uninterrupted power supply, a real-time, secure, and synchronized communication system is needed to provide the physical foundation and technical conditions. In 2005, the International Organization for Standardization (IEC) published 11 real-time Ethernet standards. Analysis and research on various real-time Ethernet standards revealed that EtherCAT real-time Ethernet can give real-time Ethernet frames a higher priority than other data frames through an internal priority system, and at the same time, it uses the IEEE 1588 time synchronization mechanism to achieve precise synchronization of distributed clocks.

[0139] Understandably, to address the real-time issues of multi-terminal DC network operation mode switching and protection coordination in uninterrupted power supply, a preliminary AC / DC system coordinated control and mode switching scheme based on EtherCAT real-time Ethernet is proposed, such as... Figure 11 As shown in the figure. The flexible DC interconnection devices communicate with each other via EtherCAT real-time Ethernet and communicate with the main station dispatch system to achieve rapid coordination and switching of control modes between stations. The controllers of the flexible DC interconnection devices use EtherCAT real-time Ethernet on-site to ensure real-time coordination between the protection device actions and the control modes of the flexible DC interconnection devices.

[0140] It should be noted that this invention addresses the load transfer control problem in AC / DC hybrid distribution networks. Based on different system states and control methods of the AC / DC hybrid distribution network, and considering the complexity of transfer optimization variables and constraints, a transfer model is proposed that considers the transfer capacity of AC tie switches and DC devices, as well as the economic and safe operating boundaries of the AC / DC system. The MADS method is used to solve this problem. Through load transfer control and optimization of the AC / DC hybrid distribution network, system network losses are reduced by 8%, and transformer imbalance is reduced by 10%. Regarding the problem of continuous power supply to local AC loads during AC-side system faults at converter stations, an uninterrupted transfer control strategy for AC / DC hybrid distribution networks is studied in depth. To solve the real-time problem of multi-terminal DC network operation mode switching and protection coordination in uninterrupted transfer, a real-time coordination technology for control mode switching of the fault-end converter station and AC system protection switch control is proposed. The uninterrupted transfer control process and the converter station priority weight calculation method are given, achieving uninterrupted transfer of important loads under AC system faults.

[0141] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0142] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0143] This embodiment also provides a load transfer control device for an AC / DC hybrid distribution network. This device is used to implement the above embodiments and preferred embodiments, and details already described will not be repeated. As used below, the terms "unit" and "device" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0144] According to an embodiment of the present invention, an apparatus embodiment for implementing the above-described load transfer control method for an AC / DC hybrid distribution network is also provided. Figure 12 This is a schematic diagram of the structure of a load transfer control device for an AC / DC hybrid distribution network according to an embodiment of the present invention, as shown below. Figure 12 As shown, the load transfer control device for the aforementioned AC / DC hybrid distribution network includes: an acquisition module 120, a first determination module 122, a first calculation module 124, a second calculation module 126, and a second determination module 128, wherein:

[0145] The aforementioned acquisition module 120 is used to acquire the current operating status of multiple converter stations in the AC / DC hybrid distribution network. The current operating status includes: the current operating parameters corresponding to the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network.

[0146] The first determining module 122 is used to determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating state.

[0147] The first calculation module 124 is used to perform power flow calculation on the AC / DC hybrid distribution network based on the load transfer constraints and a pre-built load transfer and system reconfiguration model, and obtain the power flow calculation results.

[0148] The second calculation module 126 is used to calculate the objective function value corresponding to the load transfer objective function based on the power flow calculation results.

[0149] The second determining module 128 is used to determine the load transfer control result of the AC / DC hybrid distribution network based on the objective function value.

[0150] In this embodiment of the invention, the acquisition module 120 is configured to acquire the current operating status of multiple converter stations in the AC / DC hybrid distribution network. The current operating status includes the current operating parameters corresponding to each of the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network. The first determination module 122 is configured to determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status. The first calculation module 124 is configured to calculate the load transfer objective function and load transfer constraints of the AC / DC hybrid distribution network based on the load transfer constraints using a pre-built load transfer and system reconfiguration model. The hybrid distribution network performs power flow calculations to obtain the power flow calculation results; the second calculation module 126 is used to calculate the objective function value corresponding to the load transfer objective function based on the power flow calculation results; the second determination module 128 is used to determine the load transfer control result of the AC / DC hybrid distribution network based on the objective function value, thereby achieving the purpose of load transfer control based on converter station parameter information and tie switch status information, thus realizing the technical effect of improving the control efficiency and accuracy of AC / DC hybrid distribution network, and solving the technical problems of low control efficiency and inaccurate control in the load transfer control method of the technology.

[0151] It should be noted that the above modules can be implemented by software or hardware. For example, for the latter, it can be implemented in the following ways: the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0152] It should be noted that the aforementioned acquisition module 120, first determination module 122, first calculation module 124, second calculation module 126, and second determination module 128 correspond to steps S102 to S110 in the embodiments. The instances and application scenarios implemented by the above modules and their corresponding steps are the same, but they are not limited to the content disclosed in the above embodiments. It should be noted that the above modules, as part of the device, can run in a computer terminal.

[0153] It should be noted that the optional or preferred implementation methods of this embodiment can be found in the relevant descriptions in the embodiments, and will not be repeated here.

[0154] The load transfer control device for the AC / DC hybrid distribution network described above may also include a processor and a memory. The acquisition module 120, the first determination module 122, the first calculation module 124, the second calculation module 126, the second determination module 128, etc., are all stored in the memory as program units, and the processor executes the program units stored in the memory to realize the corresponding functions.

[0155] The processor contains a core that retrieves corresponding program units from memory. One or more cores may be configured. Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory includes at least one memory chip.

[0156] According to an embodiment of this application, an embodiment of a non-volatile storage medium is also provided. Optionally, in this embodiment, the non-volatile storage medium includes a stored program, wherein, when the program is running, it controls the device where the non-volatile storage medium is located to execute any of the aforementioned AC / DC hybrid power distribution network load transfer control methods.

[0157] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals, and the non-volatile storage medium includes stored programs.

[0158] Optionally, during program execution, the device containing the non-volatile storage medium performs the following functions: acquiring the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: the current operating parameters corresponding to the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network; determining the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status; performing power flow calculation on the AC / DC hybrid distribution network using a pre-constructed load transfer and system reconfiguration model based on the load transfer constraints, and obtaining the power flow calculation results; calculating the objective function value corresponding to the load transfer objective function based on the power flow calculation results; and determining the load transfer control result of the AC / DC hybrid distribution network based on the objective function value.

[0159] Optionally, during program execution, the device containing the non-volatile storage medium performs the following functions: based on the above load transfer constraints, a grid adaptive direct search algorithm is used to perform outer-layer optimization calculations on the above load transfer and system reconfiguration model to obtain the outer-layer optimization calculation results; based on the above load transfer constraints, an alternating iterative algorithm is used to perform inner-layer power flow calculations on the above load transfer and system reconfiguration model to obtain the inner-layer optimization calculation results; based on the above outer-layer optimization calculation results and the above inner-layer optimization calculation results, the above power flow calculation results are determined.

[0160] Optionally, during program execution, the device containing the non-volatile storage medium is controlled to perform the following functions: obtain the comprehensive operational constraint index value in the above-mentioned load transfer constraint conditions; determine whether the above-mentioned multiple converter stations participate in load transfer optimization based on the above-mentioned comprehensive operational constraint index value; if the above-mentioned multiple converter stations participate in the above-mentioned load transfer optimization, then determine that the above-mentioned load transfer control result includes the target operating parameters corresponding to the above-mentioned multiple converter stations and the target switching state of the above-mentioned tie switches included in the above-mentioned AC / DC hybrid distribution network; if the above-mentioned multiple converter stations do not participate in the above-mentioned load transfer optimization, then determine that the above-mentioned load transfer control result is the above-mentioned target switching state of the above-mentioned tie switches.

[0161] Optionally, during program execution, the device containing the non-volatile storage medium may perform the following functions: obtain the current operating control mode of the multiple converter stations; determine the effective station set based on the current operating control mode; calculate the priority value corresponding to each converter station in the effective station set; and update the current operating parameters corresponding to the multiple converter stations based on the priority value.

[0162] Optionally, during program execution, the device containing the non-volatile storage medium performs the following functions: determining the updated load transfer objective function and updated load transfer constraints based on the updated current operating parameters; performing power flow calculations on the AC / DC hybrid distribution network based on the updated load transfer objective function and updated load transfer constraints to obtain updated power flow calculation results; and determining the optimized operating parameters corresponding to the multiple converter stations based on the updated power flow calculation results.

[0163] Optionally, during program execution, the device containing the non-volatile storage medium may be controlled to perform the following function: determine at least one new master station from among the multiple converter stations according to the aforementioned priority values.

[0164] According to an embodiment of this application, an embodiment of a computer program product is also provided, which, when executed on a data processing device, is adapted to execute a program that initializes the load transfer control method steps of an AC / DC hybrid distribution network having any of the above-described steps.

[0165] Optionally, when the aforementioned computer program product is executed on a data processing device, it is suitable to execute an initialization program with the following method steps: obtaining the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: the current operating parameters corresponding to the multiple converter stations respectively and the current switching status of the tie switches included in the AC / DC hybrid distribution network; determining the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status; performing power flow calculation on the AC / DC hybrid distribution network using a pre-constructed load transfer and system reconfiguration model based on the load transfer constraints, and obtaining the power flow calculation result; calculating the objective function value corresponding to the load transfer objective function based on the power flow calculation result; and determining the load transfer control result of the AC / DC hybrid distribution network based on the objective function value.

[0166] According to an embodiment of this application, an embodiment of an electronic device is also provided, including a memory and a processor. The memory stores a computer program, and the processor is configured to run the computer program to execute any of the above-described load transfer control methods for AC / DC hybrid distribution networks.

[0167] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0168] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0169] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0170] 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 units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0171] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0172] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0173] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A load transfer control method for an AC / DC hybrid distribution network, characterized in that, include: The current operating status of multiple converter stations in the AC / DC hybrid distribution network is obtained, wherein the current operating status includes: the current operating parameters corresponding to the multiple converter stations and the current switching status of the tie switches included in the AC / DC hybrid distribution network; Determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating status; Based on the load transfer constraints, a pre-built load transfer and system reconfiguration model is used to perform power flow calculations on the AC / DC hybrid distribution network to obtain the power flow calculation results. The objective function value corresponding to the load transfer objective function is calculated based on the power flow calculation results. The load transfer control result of the AC / DC hybrid distribution network is determined based on the objective function value. The step of performing power flow calculations on the AC / DC hybrid distribution network based on the load transfer constraints and using a pre-constructed load transfer and system reconfiguration model to obtain power flow calculation results includes: performing outer-layer optimization calculations on the load transfer and system reconfiguration model using a grid adaptive direct search algorithm based on the load transfer constraints to obtain outer-layer optimization calculation results; performing inner-layer power flow calculations on the load transfer and system reconfiguration model using an alternating iterative algorithm based on the load transfer constraints to obtain inner-layer optimization calculation results; and determining the power flow calculation results based on the outer-layer optimization calculation results and the inner-layer optimization calculation results.

2. The method according to claim 1, characterized in that, The process of determining the load transfer control result of the AC / DC hybrid distribution network based on the objective function value includes: Obtain the comprehensive operational constraint index value from the load transfer constraints; Based on the comprehensive operational constraint index values, determine whether the multiple converter stations participate in load transfer optimization; If the multiple converter stations participate in the load transfer optimization, the load transfer control result is determined to include the target operating parameters corresponding to the multiple converter stations and the target switching status of the tie switches included in the AC / DC hybrid distribution network. If the multiple converter stations do not participate in the load transfer optimization, then the load transfer control result is determined to be the target switch state of the included tie switches.

3. The method according to claim 1, characterized in that, When a fault is detected in any converter station in the AC / DC hybrid distribution network, the method further includes: Obtain the current operating control mode of the plurality of converter stations; The set of valid stations is determined based on the current operation control mode. Calculate the priority value corresponding to each converter station in the set of effective stations; The current operating parameters corresponding to the plurality of converter stations are updated according to the priority value.

4. The method according to claim 3, characterized in that, The method further includes: Based on the updated current operating parameters, the updated load transfer objective function and updated load transfer constraints are determined. Based on the updated load transfer objective function and the updated load transfer constraints, power flow calculations are performed on the AC / DC hybrid distribution network to obtain the updated power flow calculation results. Based on the updated power flow calculation results, the optimized operating parameters corresponding to the multiple converter stations are determined respectively.

5. The method according to claim 3, characterized in that, When determining the current operating control mode as a master-slave control mode, the method further includes: At least one new master station is determined from the plurality of converter stations based on the priority value.

6. The method according to any one of claims 1 to 5, characterized in that, The AC / DC hybrid power distribution network uses EtherCAT for real-time communication.

7. A load transfer control device for an AC / DC hybrid distribution network, characterized in that, include: The acquisition module is used to acquire the current operating status of multiple converter stations in the AC / DC hybrid distribution network, wherein the current operating status includes: the current operating parameters corresponding to the multiple converter stations respectively and the current switching status of the tie switches included in the AC / DC hybrid distribution network; The first determining module is used to determine the load transfer objective function and load transfer constraints corresponding to the AC / DC hybrid distribution network based on the current operating state. The first calculation module is used to perform power flow calculation on the AC / DC hybrid distribution network based on the load transfer constraints and using a pre-built load transfer and system reconfiguration model to obtain the power flow calculation results. The second calculation module is used to calculate the objective function value corresponding to the load transfer objective function based on the power flow calculation results; The second determining module is used to determine the load transfer control result of the AC / DC hybrid distribution network based on the objective function value; The first calculation module is further configured to perform outer-layer optimization calculations on the load transfer and system reconfiguration model based on the load transfer constraints using a grid adaptive direct search algorithm to obtain outer-layer optimization calculation results; perform inner-layer power flow calculations on the load transfer and system reconfiguration model based on the load transfer constraints using an alternating iterative algorithm to obtain inner-layer optimization calculation results; and determine the power flow calculation results based on the outer-layer optimization calculation results and the inner-layer optimization calculation results.

8. A non-volatile storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the load transfer control method for the AC / DC hybrid distribution network according to any one of claims 1 to 6.

9. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the load transfer control method for an AC / DC hybrid distribution network as described in any one of claims 1 to 6.

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