Multi-target dynamic equivalence system construction method and device of extra-high voltage alternating current power grid

Abstract

The invention provides a multi-target dynamic equivalence system construction method and device for an extra-high voltage alternating current power grid, and relates to the technical field of extra-high voltage alternating current transmission, and the method comprises the steps: obtaining the basic information of a power grid system, the basic information at least comprising a power supply, a load and actual power flow distribution; representing a power supply and a load by using different identifiers to obtain an initial equivalent model of the power grid system; constructing a power flow function of each coupling node in the initial equivalent model, and obtaining ideal power flow distribution of the initial equivalent model based on the power flow functions; and when the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value, outputting the initial equivalent model as a target equivalent model of the power grid system. The target equivalent model output by the method is a model after the scale of the power grid system is simplified, simulation analysis is performed on the power grid system based on the model, the actual operation condition of the power grid system after new energy is newly added can be obtained, the line of the power grid system can be optimized, and the intelligent management level of the power grid system is improved.

Description

Technical Field

[0001] This application relates to the field of ultra-high voltage AC power transmission technology, and in particular to a method and apparatus for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid. Background Technology

[0002] Ultra-high voltage (UHV) AC power grid technology, as a core means of long-distance, high-capacity power transmission, has been widely used in numerous major projects. Currently, the main UHV AC transmission structures employed—single-circuit, double-circuit, and multi-port—each demonstrate their advantages in different application scenarios. Single-circuit structures have low construction costs and short construction periods, making them suitable for areas with low power demand; double-circuit structures offer high reliability and stronger power supply capacity, but require larger investments and are more suitable for areas with dense loads; multi-port structures offer flexible, multi-directional power transmission capabilities and can support distributed energy integration, but their system complexity and operation and maintenance costs are significantly higher. Although existing structures meet the basic operational needs of the power grid to some extent, they still struggle to fully adapt to the system stability requirements under high-proportion renewable energy integration and complex load structures.

[0003] As the scale of ultra-high voltage (UHV) AC power grids continues to expand, their inherent technical challenges are becoming increasingly prominent. On the one hand, the power flow distribution of the system is becoming increasingly complex, which can easily lead to operational instability and control difficulties, especially in grid structures with multiple feeders and interwoven circuits, where voltage stability and power balance issues are more pronounced. On the other hand, higher short-circuit current levels place more stringent requirements on equipment insulation performance and relay protection systems, and existing protection configurations and fault isolation strategies face severe tests under extreme operating conditions. These problems are particularly prominent in regions with rapidly growing electricity demand and highly complex grid structures (such as the Yangtze River Delta region), limiting the overall effectiveness of UHV AC power grids.

[0004] Therefore, it is necessary to conduct more refined equivalent system modeling for specific regions such as the Yangtze River Delta, taking into account the characteristics of the power grid structure and future development needs, so as to provide a theoretical basis for the optimized design and reliable operation of the UHV AC power grid. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a method and apparatus for constructing a multi-objective dynamic equivalent system for ultra-high voltage (UHV) AC power grids. This method and apparatus are used to construct an equivalent model with a simplified power grid system scale, providing a theoretical basis for the optimized design and reliable operation of UHV AC power grids. The technical solution is as follows:

[0006] Firstly, a method for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid is provided, including:

[0007] Obtain basic information about the power grid system, including at least power sources, loads, and actual power flow distribution;

[0008] By using different identifiers to represent the power source and the load, an initial equivalent model of the power grid system is obtained.

[0009] Construct the power flow function for each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function;

[0010] When the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value, the initial equivalent model is output as the target equivalent model of the power grid system.

[0011] In one possible implementation, constructing the power flow function for each coupled node in the initial equivalent model includes:

[0012] Determine the coupling nodes in the initial equivalent model, wherein each coupling node is at least the intersection of two lines in the initial equivalent model;

[0013] A port equivalence architecture is established based on the aforementioned coupling nodes;

[0014] The power flow function of the coupled node is constructed based on the port equivalent architecture.

[0015] In one possible implementation, when the port equivalence architecture is a two-port equivalence architecture, the step of establishing the port equivalence architecture based on the coupled node includes:

[0016] Identify two adjacent coupled nodes;

[0017] One of the two adjacent coupled nodes is taken as the first node, and the other coupled node is taken as the second node;

[0018] The line where the first node is located is designated as the first equivalent line, the line where the second node is located is designated as the second equivalent line, and the load identifier between the first equivalent line and the second equivalent line is designated as an internal sub-network, the internal sub-network including a first port and a second port;

[0019] The first equivalent line is connected to the first port of the internal sub-network, and the second equivalent line is connected to the second port of the internal sub-network, thus obtaining the two-port equivalent architecture.

[0020] In one possible implementation, when the port equivalence architecture is a two-port equivalence architecture, the power flow function of the coupled node is:

[0021]

[0022] Among them, P i and Q iLet represent the active power and reactive power input to coupled node i, respectively. This represents the isopoint voltage of the internal subnet. G represents the equivalent point voltage of the outer subnet, which refers to the portion of the two-port equivalent architecture excluding the inner subnet. i jB represents the conductance of the connection between the internal and external subnets. i The susceptance represents the connection between the internal subnetwork and the external subnetwork.

[0023] In one possible implementation, when the boundary nodes of the two-port equivalence architecture are coupled, the power flow function is modified, and the modified power flow function is:

[0024]

[0025] Where, θ i This represents the voltage phase angle difference between coupled node i and the next coupled node i+1. Coupled node i and the next coupled node i+1 are adjacent. δ i Indicates the voltage phase angle;

[0026]

[0027] Where U1 and U2 represent the voltages at coupling nodes 1 and 2, respectively, and G 12 B represents the conductance of the connection between coupling node 1 and coupling node 2, θ1 and θ2 represent the voltage phase angles of coupling nodes 1 and 2, respectively. 12 This represents the susceptance of the connection between coupling node 1 and coupling node 2.

[0028] In one possible implementation, obtaining the ideal power flow distribution of the initial equivalent model based on the power flow function includes:

[0029] The ideal power flow distribution is obtained by fusing the power flow functions of all coupled nodes in the initial equivalent model.

[0030] In one possible implementation, after obtaining the ideal power flow distribution, the method further includes:

[0031] When a fault occurs in the power grid system, the positive sequence short-circuit current of the initial equivalent model is calculated;

[0032] The short-circuit current at the fault location is calculated based on the positive sequence short-circuit current.

[0033] In one possible implementation, the positive-sequence short-circuit current is calculated using the following formula:

[0034]

[0035] in, Z represents the actual operating voltage before the fault location. eq1A Z represents the equivalent positive-sequence impedance indicating the fault location. Δ This indicates the additional impedance when a fault occurs.

[0036] In one possible implementation, the method includes:

[0037] The power source is identified by its series impedance.

[0038] The load is identified by the load and / or by a combination of power supply and load.

[0039] Secondly, a multi-objective dynamic equivalent system construction device for ultra-high voltage AC power grids is provided, comprising:

[0040] The data acquisition module is used to acquire basic information about the power grid system, including at least power sources, loads, and actual power flow distribution.

[0041] The data processing module is used to represent the power source and the load using different identifiers to obtain an initial equivalent model of the power grid system;

[0042] The data construction module is used to construct the power flow function of each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function;

[0043] The data output module is used to output the initial equivalent model as the target equivalent model of the power grid system when the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value.

[0044] The technical solutions provided in this application can achieve the following technical effects:

[0045] (1) This application uses different identifiers to replace the power sources and loads in the power grid system to obtain an initial equivalent model after simplifying the scale of the power grid system. Then, by comparing the ideal power flow distribution obtained based on the initial equivalent model with the actual power flow distribution of the power grid system, when the similarity between the two reaches a preset value, the initial equivalent model is output as the target equivalent model of the power grid system, ensuring that the target equivalent model is close to or equal to the power grid system, that is, ensuring the accuracy of the obtained target equivalent model, so as to facilitate the subsequent dynamic calculation of the power flow distribution and short-circuit current of the power grid system based on the target equivalent model.

[0046] (2) In the process of obtaining the ideal power flow distribution, this application first determines the coupling nodes in the initial equivalent model, then constructs a two-port equivalent architecture based on the coupling nodes, and then establishes a power flow function based on the two-port equivalent architecture to obtain the ideal power flow distribution. That is, by splitting the initial equivalent model into multiple two-port equivalent architectures, it is applicable to multi-port power grid systems with coupling relationships, which can effectively simplify the complex power grid structure of the initial equivalent model and ensure the accuracy of the calculated ideal power flow distribution.

[0047] (3) Based on the obtained target equivalent model, the operating parameters of each device in the power grid system are input into the target equivalent model for simulation experiments. Then, the short-circuit current of the single-circuit UHV AC transmission structure, double-circuit UHV AC transmission structure and multi-port UHV AC transmission structure of the power grid system can be calculated in detail. By comparing the advantages and disadvantages of different UHV AC transmission structures, a scientific basis can be provided for optimizing the UHV AC power grid in a specific area. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. In the drawings:

[0049] Figure 1 This is a flowchart of a method for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid according to an embodiment of this application;

[0050] Figure 2 This is an example diagram illustrating the use of a load instead of a load in the method embodiments of this application;

[0051] Figure 3 This is an example diagram illustrating the use of a combination of power supply and load to replace the load in the method embodiments of this application;

[0052] Figure 4 This is an example diagram illustrating the determination of coupling nodes in the initial isometry model in the method embodiments of this application;

[0053] Figure 5 This is an example diagram of a two-port equivalence architecture in the method embodiments of this application;

[0054] Figure 6 This is a structural block diagram of a multi-objective dynamic equivalent system construction device for an ultra-high voltage AC power grid according to an embodiment of this application;

[0055] Figure 7 This is a structural diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0056] Exemplary embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0057] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the term "comprising" and its variations should be interpreted as open-ended terms meaning "including but not limited to."

[0058] With the advancement of the "dual-carbon" goals, the proportion of renewable energy generation is continuously increasing, leading to rapid growth in electricity demand and highly complex grid structures in some power grid systems, such as the Yangtze River Delta region. To optimize power resource allocation in these specific regions, reduce transmission losses and improve transmission efficiency, promote the efficient utilization of renewable energy, and ensure the safe and stable operation of the power grid, this paper takes the ultra-high-voltage AC power grid in the Yangtze River Delta region as an example and proposes a multi-objective dynamic equivalent system construction method for ultra-high-voltage AC power grids. In practical applications, this method can also be applied to other regions with rapidly growing electricity demand and highly complex grid structures; this embodiment does not impose any limitations.

[0059] like Figure 1 As shown, a method for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid mainly includes steps S101 to S104.

[0060] Step S101: Obtain basic information about the power grid system. The basic information includes at least the power source, load, and actual power flow distribution.

[0061] Since this embodiment uses the UHV AC power grid in the Yangtze River Delta region as an example, the power grid system referred to here is the UHV AC power grid in the Yangtze River Delta region. For this power grid system, the power sources and loads in the power grid system are collected in advance. Power sources include generators in the power grid system, while electronic devices that consume electrical energy in the power grid system are collectively referred to as loads, such as transformers as loads and voltage transformers as loads. Because the power grid system includes not only power sources and loads, but also connections between power sources and loads, and between loads, this embodiment will also collect the connections between power sources and loads, and between loads, in the power grid system. Alternatively, the power sources, loads, and connections between power sources and loads, and between loads, can also be obtained directly from a database specifically used for managing the UHV AC power grid in the Yangtze River Delta region.

[0062] In addition, the actual power flow distribution of the power grid system is obtained from the aforementioned database. This actual power flow distribution refers to the voltage amplitude and phase angle on all high-voltage buses in the power grid system, as well as the active and reactive power flowing on all lines. Simply put, the actual power flow distribution is a detailed "panoramic view of the power grid's operating status," accurately reflecting the voltage level, active power, and reactive power flow direction and magnitude at each location in the UHV AC power grid of the Yangtze River Delta region. The actual power flow distribution is obtained by pre-measuring the voltage, current, active power, and reactive power at various locations in the power grid system and storing these values ​​in the database for later retrieval.

[0063] Step S102: Use different identifiers to represent power sources and loads to obtain the initial equivalent model of the power grid system.

[0064] First, the voltage source series impedance is used as the power supply identifier.

[0065] Secondly, load can be used as an identifier for the load, such as Figure 2 The example uses load to represent load, with the low-voltage bus representing a load. This identification method minimizes the size of the simplified power grid system, facilitating the rapid establishment of an initial equivalent model corresponding to the power grid system. However, for power grid systems with complex structures, this identification method may lose the dynamic characteristics of the power grid system itself, introducing certain errors. Therefore, this embodiment also provides another load identification method: using a combination of power source and load as the load identifier, such as... Figure 3 An example is using a combination of power source and load to replace the load, where resistor R1 and power source V1 represent a load. This notation not only simplifies the scale of the power grid system but also preserves more of the dynamic characteristics of the power grid system itself and provides sufficient voltage support for the power grid system, thus balancing the simplification of the power grid system's scale with the accuracy of the simplified initial equivalent model.

[0066] In this embodiment, since the power grid system includes not only power sources and loads, but also the connection methods between power sources and loads, and between loads, a simplified power grid system is obtained by identifying the power sources and loads respectively and retaining the connection relationships between the identified power sources and identified loads, which is also called the initial equivalent model.

[0067] Step S103: Construct the power flow function for each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function.

[0068] First, identify the coupling nodes in the initial equivalent model. Each coupling node is at least the intersection of two lines in the initial equivalent model. For power grid systems with complex structures, a coupling node may be the intersection of more than two lines. Each line refers to the connection line between the identified power source and the identified load, or the connection line between the identified loads. For example... Figure 4 For example, suppose there are five main lines and six branch lines, denoted as A, B, C, D, E and a, b, c, d, e, f respectively. Main line A is equipped with a rectifier DC1 and a generator U. A The load is replaced by a power supply u1 connected in series with a resistor Z1; a rectifier DC2 and a generator U are installed on the main line B. B The load is replaced by a power supply u2 connected in series with a resistor Z2; a rectifier DC3 and a generator U are installed on the main line C. C The load is replaced by a power supply u3 connected in series with a resistor Z3; a rectifier DC4 and a generator U are installed on the main line D. D The load is replaced by a power supply u4 connected in series with a resistor Z4; a rectifier DC5 and a generator U are installed on the main line E. E The load is represented by power supply u5 in series with resistor Z5. Branch line a refers to the load installed between main line A and main line C, denoted by Z. 1,3 Branch line b refers to the load installed between main line B and main line D. This load may be a transformer, denoted by Z. 2,4 Branch line c is the load installed between main line C and main line E, denoted by Z. 3,5 Branch line d refers to the load erected between main line A and main line D, denoted by Z. 1,4 Branch line e refers to the load installed between main line B and main line F. This load may be a transformer, denoted by Z. 2,5 Branch line f refers to the load erected between main line A and main line F, denoted by Z. 1,5In addition, voltage stabilizing components may be installed between adjacent main lines, such as those between main line A and main line B, consisting of Qc and load Z. 1,2 A voltage regulator assembly connected in parallel. Figure 4 In the example, since branches a, d, and f are all connected to main line A, the points where the three branches intersect with main line A are considered as one coupling node. Similarly, the points where branches b and e intersect with main line B are considered as one coupling node, the points where branches a and c intersect with main line C are considered as one coupling node, the points where branches b and d intersect with main line D are considered as one coupling node, and the points where branches c, e, and f intersect with main line E are considered as one coupling node.

[0069] Then, a port equivalent architecture is established based on the coupled nodes. The equivalent architecture, also known as the equivalent network, simplifies a complex power grid system into a "black box" model with a few ports connected to the outside. The external electrical characteristics of the black box are completely equivalent to the original complex power grid system at that port. Depending on the number of ports, the complexity of the interaction relationships that the equivalent architecture can represent varies. In this embodiment, the initial equivalent model is split into multiple two-port equivalent architectures.

[0070] The process of establishing a two-port equivalence architecture mainly includes: first, identifying two adjacent coupled nodes, designating one of them as the first node and the other as the second node. Then, the line containing the first node is designated as the first equivalence line, and the line containing the second node is designated as the second equivalence line. The load identifier between the first and second equivalence lines is treated as an internal subnet, which includes both the first and second ports. Finally, the first equivalence line is connected to the first port of the internal subnet, and the second equivalence line is connected to the second port of the internal subnet, resulting in the two-port equivalence architecture. (As described above.) Figure 4 The example in the text uses two adjacent coupled nodes on main line A and main line B as a two-port equivalence architecture, resulting in the following: Figure 5 The two-port equivalent architecture shown has coupling node O. A and O B These represent the coupling nodes on main lines A and B, respectively.

[0071] Finally, the power flow function for the coupled nodes is constructed based on the port equivalence architecture. Since this embodiment establishes a two-port equivalence architecture, the power flow function for each two-port equivalence architecture is as follows:

[0072]

[0073] Among them, P i and Q iLet represent the active power and reactive power input to coupled node i, respectively. This represents the isopoint voltage of the internal subnet. G represents the equivalent point voltage of the outer subnet, which refers to the portion of the two-port equivalent architecture excluding the inner subnet. i jB represents the conductance of the connection between the internal and external subnets. i The susceptance represents the connection between the internal subnetwork and the external subnetwork.

[0074] Substituting the parameters of the external subnetwork into the power flow function and separating the real and imaginary parts of the power flow function, we obtain:

[0075]

[0076] Among them, E i U still represents the isopoint voltage of the external subnetwork. i Still representing the isopoint voltage of the internal subnet, θ i This represents the voltage phase angle difference between coupled node i and the next coupled node i+1. Coupled node i and the next coupled node i+1 are adjacent. δ i This indicates the voltage phase angle.

[0077] Furthermore, when there is coupling at the boundary nodes of a two-port equivalent architecture, these boundary nodes are the electrical nodes where the two-port equivalent architecture interacts with the external power system or other two-port equivalent architectures. In this case, the power flow function needs to be modified. The modified power flow function is as follows:

[0078]

[0079] in:

[0080]

[0081] Where U1 and U2 represent the voltages at coupling nodes 1 and 2, respectively, and G 12 B represents the conductance of the connection between coupling node 1 and coupling node 2, θ1 and θ2 represent the voltage phase angles of coupling nodes 1 and 2, respectively. 12 This represents the susceptance of the connection between coupling node 1 and coupling node 2.

[0082] Therefore, following the above process, the power flow function corresponding to each two-port equivalent architecture can be obtained. Then, by fusing the power flow functions of all coupled nodes in the initial equivalent model, the values ​​of voltage, current, active power, and reactive power at any location in the initial equivalent model can be obtained, thus obtaining the power flow distribution of the initial equivalent model. In this embodiment, the power flow distribution of the initial equivalent model is referred to as the ideal power flow distribution.

[0083] Based on the obtained ideal power flow distribution, when a fault occurs in the actual power grid system, considering the influence of generator electromotive force, load current, ground branches, parallel compensation, and non-standard transformer ratios, the positive sequence short-circuit current at the fault location can be calculated using the following formula:

[0084]

[0085] in, Z represents the actual operating voltage before the fault location. eq1A Z represents the equivalent positive-sequence impedance indicating the fault location. Δ This indicates the additional impedance when a fault occurs.

[0086] In other words, by establishing an initial equivalent model that is equivalent to the actual power grid system, and obtaining an ideal power flow distribution based on the initial equivalent model, the positive sequence short-circuit current at the fault location can be obtained based on the ideal power flow distribution. There is no need to use detection equipment to monitor and calculate the actual power grid system, thus improving the monitoring level of the actual power grid system.

[0087] Step S104: When the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value, the initial equivalent model is output as the target equivalent model of the power grid system.

[0088] In this embodiment, the similarity between the ideal power flow distribution and the actual power flow distribution is calculated. A higher degree of overlap between the ideal and actual power flow distributions indicates that the initial equivalent model is closer to the actual power grid system, and the higher the similarity. When the similarity reaches a preset value, such as 95% or higher, the initial equivalent model is output as the target equivalent model for the power grid system. Subsequently, the operation of the power grid system will be remotely monitored or optimized by monitoring the target equivalent model or conducting simulation experiments on it. Otherwise, if the similarity does not reach the preset value, the initial equivalent model corresponding to the power grid system will be reconstructed until the similarity reaches the preset value.

[0089] In summary, the implementation principle of the multi-objective dynamic equivalent system construction method for an ultra-high voltage AC power grid provided in this application is as follows: First, basic information such as the power sources, loads, and actual power flow distribution of the power grid system is obtained. Based on the obtained power sources and loads, different identifiers are used to replace them to obtain a simplified initial equivalent model. Then, the coupling nodes in the initial equivalent model are determined, and a power flow function is constructed for each coupling node. The power flow functions of all coupling nodes are merged to obtain an ideal power flow distribution. Finally, the similarity between the ideal power flow distribution and the actual power flow distribution is calculated. When the similarity between the two reaches a preset value, the initial equivalent model is output as the target equivalent model of the power grid system. In subsequent monitoring processes, even if the power grid system adds new energy sources, making the power grid structure more complex, calculations can be performed in the target equivalent model to obtain the actual operating conditions of the changed power grid system, or simulation experiments based on the target equivalent model can be conducted to optimize the power grid system lines and improve the intelligent management level of the power grid system.

[0090] In this embodiment, the power flow distribution in the Yangtze River Delta region is obtained using the methods described in steps S101 to S104 above, and calculations are performed based on the power flow distribution. Figure 4 The short-circuit currents of each generator in the example include calculations of the short-circuit currents of single-circuit UHV AC transmission structures, double-circuit UHV AC transmission structures, and multi-port UHV AC transmission structures, resulting in the short-circuit currents shown in Tables 1 to 3. The unit of the short-circuit current is kA. Meanwhile, it is assumed that… Figure 4 U in the example A =U C =U D =U E =1000kV, U B =500kV, and U A The output capacity is 6400MW, U B The output capacity is 1200MW, U C U D U E If the output capacity is 3000MW, then we get:

[0091] Generator markings Three-phase electricity Single-phase electricity <![CDATA[U A ]]> 43.9 45.1 <![CDATA[U B ]]> 55.3 53.8 <![CDATA[U C ]]> 43.8 45.0 <![CDATA[U D ]]> 44.0 45.0 <![CDATA[U E ]]> 43.1 44.5

[0092] Table 1

[0093] Generator markings Three-phase electricity Single-phase electricity UA 54.2 55.3 UB 64.3 65.4 UC 55.2 56.1 UD 53.2 54.3 UE 54.2 53.3

[0094] Table 2

[0095]

[0096]

[0097] Table 3

[0098] As shown in Tables 1 to 3, under the same voltage level and power conditions, the multi-port UHV AC transmission structure has the smallest short-circuit current, followed by the single-circuit UHV AC transmission structure, while the double-circuit UHV AC transmission structure has the largest short-circuit current. Since the single-circuit UHV AC transmission structure has only one circuit, the short-circuit current is transmitted only through this single circuit, and there is no superposition effect of parallel circuits. Therefore, compared with the double-circuit UHV AC transmission structure, its short-circuit current is smaller. However, the single-circuit UHV AC transmission structure is more suitable for areas with low initial power demand or low requirements for short-circuit current, and is obviously not suitable for specific areas with complex power grid structures like the Yangtze River Delta region. Compared with the single-circuit UHV AC transmission structure, the multi-port UHV AC transmission structure has a smaller short-circuit current. This is due to its multi-point distribution and current shunting characteristics, which allow the fault current to be dispersed among multiple ports, thereby reducing the current value at each port.

[0099] Therefore, by establishing the same target equivalent model as a specific region, and by comparing the short-circuit currents calculated under single-circuit UHV AC transmission structures, double-circuit UHV AC transmission structures, and multi-port UHV AC transmission structures in detail based on the target equivalent model, and by evaluating the power flow distribution, short-circuit current, and development adaptability of different UHV AC transmission structures in detail, a scientific basis is provided for the transformation and optimization of specific regions, so as to better cope with the increasingly complex power grid structure.

[0100] It should be noted that the sequence numbers of the steps in the above embodiments do not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. In practical applications, all the above possible implementation methods can be arbitrarily combined in a combined manner to form possible embodiments of this application, which will not be described in detail here.

[0101] Based on the multi-objective dynamic equivalent system construction method for an ultra-high voltage AC power grid provided in the above embodiments, and based on the same inventive concept, this application also provides a multi-objective dynamic equivalent system construction device for an ultra-high voltage AC power grid.

[0102] Figure 6 This is a structural diagram of a multi-objective dynamic equivalent system construction device for an ultra-high voltage AC power grid provided in an embodiment of this application. Figure 6 As shown, the device may specifically include a data acquisition module, a data processing module, a data construction module, and a data output module.

[0103] The data acquisition module is used to acquire basic information about the power grid system, which includes at least power sources, loads, and actual power flow distribution.

[0104] The data processing module is used to represent power sources and loads using different identifiers to obtain the initial equivalent model of the power grid system;

[0105] The data construction module is used to construct the power flow function for each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function;

[0106] The data output module is used to output the initial equivalent model as the target equivalent model of the power grid system when the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value.

[0107] This embodiment provides a multi-objective dynamic equivalent system construction device for an ultra-high voltage AC power grid, which is used to execute the multi-objective dynamic equivalent system construction method for an ultra-high voltage AC power grid provided in the above embodiment. Its implementation method and principle are the same. For details of the implementation method of each module, please refer to the relevant description of the above method embodiment, which will not be repeated here.

[0108] Based on the same inventive concept, this application also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute a method for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid according to any of the above embodiments.

[0109] In an exemplary embodiment, an electronic device is provided, such as Figure 7 As shown, Figure 7 The illustrated electronic device 700 includes a processor 701 and a memory 703. The processor 701 and the memory 703 are connected, for example, via a bus 702. Optionally, the electronic device 700 may also include a transceiver 704. It should be noted that in practical applications, the transceiver 704 is not limited to one type, and the structure of this electronic device 700 does not constitute a limitation on the embodiments of this application.

[0110] Processor 701 may be a CPU (Central Processing Unit), DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 701 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0111] Bus 702 may include a pathway for transmitting information between the aforementioned components. Bus 702 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 702 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0112] The memory 703 may be a ROM (Read Only Memory) or other type of static storage device capable of storing static information and instructions, RAM (Random Access Memory) or other type of dynamic storage device capable of storing information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto.

[0113] The memory 703 stores computer program code that executes the scheme of this application, and its execution is controlled by the processor 701. The processor 701 executes the computer program code stored in the memory 703 to implement the content shown in the foregoing method embodiments.

[0114] Among them, electronic devices include, but are not limited to: mobile terminals such as mobile phones, laptops, digital radio receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), and in-vehicle terminals (such as in-vehicle navigation terminals), as well as fixed terminals such as digital TVs and desktop computers. Figure 7 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0115] Based on the same inventive concept, this application also provides a storage medium storing a computer program, wherein the computer program is configured to execute, at runtime, a method for constructing a multi-objective dynamic equivalent system of an ultra-high voltage AC power grid according to any of the above embodiments.

[0116] Those skilled in the art will clearly understand that the specific working process of the systems, devices, and modules described above can be referred to the corresponding process in the foregoing method embodiments. For the sake of brevity, it will not be repeated here.

[0117] Those skilled in the art will understand that the technical solution of this application, 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 program instructions to cause an electronic device (e.g., a personal computer, server, or network device) to execute all or part of the steps of the methods described in the embodiments of this application when running the program instructions. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0118] Alternatively, all or part of the steps of the foregoing method embodiments can be implemented by hardware (such as electronic devices like personal computers, servers, or network devices) associated with program instructions. The program instructions can be stored in a computer-readable storage medium. When the program instructions are executed by the processor of the electronic device, the electronic device executes all or part of the steps of the methods described in the embodiments of this application.

[0119] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that within the spirit and principles of this application, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the corresponding technical solutions to leave the protection scope of this application.

Claims

1. A method for constructing a multi-objective dynamic equivalent system for an ultra-high voltage AC power grid, characterized in that, include: Obtain basic information about the power grid system, including at least power sources, loads, and actual power flow distribution; By using different identifiers to represent the power source and the load, an initial equivalent model of the power grid system is obtained. Construct the power flow function for each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function; When the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value, the initial equivalent model is output as the target equivalent model of the power grid system.

2. The method according to claim 1, characterized in that, The power flow function for each coupled node in the initial equivalent model includes: Determine the coupling nodes in the initial equivalent model, wherein each coupling node is at least the intersection of two lines in the initial equivalent model; A port equivalence architecture is established based on the aforementioned coupling nodes; The power flow function of the coupled node is constructed based on the port equivalent architecture.

3. The method according to claim 2, characterized in that, When the port equivalence architecture is a two-port equivalence architecture, the step of establishing the port equivalence architecture based on the coupled node includes: Identify two adjacent coupled nodes; One of the two adjacent coupled nodes is taken as the first node, and the other coupled node is taken as the second node; The line where the first node is located is designated as the first equivalent line, the line where the second node is located is designated as the second equivalent line, and the load identifier between the first equivalent line and the second equivalent line is designated as an internal sub-network, the internal sub-network including a first port and a second port; The first equivalent line is connected to the first port of the internal sub-network, and the second equivalent line is connected to the second port of the internal sub-network, thus obtaining the two-port equivalent architecture.

4. The method according to claim 3, characterized in that, When the port equivalence architecture is a two-port equivalence architecture, the power flow function of the coupled node is: Among them, P i and Q i Let represent the active power and reactive power input to coupled node i, respectively. This represents the isopoint voltage of the internal subnet. G represents the equivalent point voltage of the outer subnet, which refers to the portion of the two-port equivalent architecture excluding the inner subnet. i jB represents the conductance of the connection between the internal and external subnets. i The susceptance represents the connection between the internal subnetwork and the external subnetwork.

5. The method according to claim 4, characterized in that, The method further includes: when there is coupling at the boundary nodes of the two-port equivalence architecture, modifying the power flow function, wherein the modified power flow function is: Where, θ i This represents the voltage phase angle difference between coupled node i and the next coupled node i+1. Coupled node i and the next coupled node i+1 are adjacent. δ i Indicates the voltage phase angle; Where U1 and U2 represent the voltages at coupling nodes 1 and 2, respectively, and G 12 B represents the conductance of the connection between coupling node 1 and coupling node 2, θ1 and θ2 represent the voltage phase angles of coupling nodes 1 and 2, respectively. 12 This represents the susceptance of the connection between coupling node 1 and coupling node 2.

6. The method according to any one of claims 1-5, characterized in that, The process of obtaining the ideal power flow distribution of the initial equivalent model based on the power flow function includes: The ideal power flow distribution is obtained by fusing the power flow functions of all coupled nodes in the initial equivalent model.

7. The method according to claim 1, characterized in that, After obtaining the ideal power flow distribution, the method further includes: When a fault occurs in the power grid system, the positive sequence short-circuit current of the initial equivalent model is calculated; The short-circuit current at the fault location is calculated based on the positive sequence short-circuit current.

8. The method according to claim 7, characterized in that, The positive sequence short-circuit current is calculated using the following formula: in, Z represents the actual operating voltage before the fault location. eq1A Z represents the equivalent positive-sequence impedance indicating the fault location. Δ This indicates the additional impedance when a fault occurs.

9. The method according to claim 1, characterized in that, The method includes: The power source is identified by its series impedance. The load is identified by the load and / or by a combination of power supply and load.

10. A multi-objective dynamic equivalent system construction device for an ultra-high voltage AC power grid, characterized in that, include: The data acquisition module is used to acquire basic information about the power grid system, including at least power sources, loads, and actual power flow distribution. The data processing module is used to represent the power source and the load using different identifiers to obtain an initial equivalent model of the power grid system; The data construction module is used to construct the power flow function of each coupled node in the initial equivalent model, and obtain the ideal power flow distribution of the initial equivalent model based on the power flow function; The data output module is used to output the initial equivalent model as the target equivalent model of the power grid system when the similarity between the ideal power flow distribution and the actual power flow distribution reaches a preset value.

Images