Middle and low voltage collaborative flexible interconnection equipment planning method and device

Abstract

The invention relates to a medium and low voltage collaborative flexible interconnection equipment planning method and device, and the method comprises the steps: analyzing the source load characteristics of all low-voltage transformer areas in a power distribution network, classifying all low-voltage transformer areas based on an analysis result, and generating a to-be-selected access position scheme of low-voltage flexible interconnection equipment according to a transformer area flexible interconnection division principle; constructing a direct-current power flow type double-layer planning model; and inputting the to-be-selected access position scheme into the direct current power flow type double-layer planning model, and solving the direct current power flow type double-layer planning model to obtain an optimal configuration scheme of the flexible interconnection equipment. According to the method, the number of flexible interconnection alternative positions can be reduced, and the model complexity is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network planning and optimal configuration, and in particular to a method and device for planning medium and low voltage coordinated flexible interconnection equipment. Background Art

[0002] With the development of power electronics technology, flexible interconnected devices (FIDs) as a new type of distribution equipment have received widespread attention in the medium and low voltage systems of distribution networks. Medium voltage uses intelligent soft open point (SOP) as a flexible interconnection device, aiming to replace traditional circuit breaker interconnection switches with controllable power electronic equipment, realize flexible connection between feeders, and provide high-efficiency control and power flow optimization. Compared with traditional interconnection switches, SOPs have the ability of continuous power control and power flow regulation, solving problems such as power outages. At the same time, SOPs change the operation mode of the distribution network and are expected to solve the problems of power outages and limited power supply capacity improvement. Low voltage uses low voltage FID as a flexible interconnection device to interconnect multiple substations with source-load complementarity in the same distribution area. By balancing the load of interconnected low voltage substations, the risk of heavy load and overload of substation transformers can be effectively reduced. At the same time, stable voltage support is provided for the substation, solving the problems caused by the high proportion of intermittent distributed generation access to low voltage substations and overload operation of substation transformers.

[0003] At present, most of the research on the coordinated planning of flexible interconnected equipment in low-voltage distribution networks focuses on the configuration stage of flexible interconnected equipment in low-voltage distribution networks, and usually uses intelligent algorithms for optimization and solution. However, in these methods, the actual characteristics of the source and load in the low-voltage distribution network are often ignored. Even in the low-voltage distribution network with similar source and load composition, the possibility of interconnection may not exist. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and device for planning medium and low voltage coordinated flexible interconnection equipment, which can reduce the number of flexible interconnection alternative positions and reduce the complexity of the model.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a method for planning medium and low voltage coordinated flexible interconnection equipment, comprising the following steps:

[0006] Analyze the source-load characteristics of each low-voltage area in the distribution network, and classify each low-voltage area based on the analysis results. Then, based on the principle of flexible interconnection division of the area, generate the candidate access location plan for low-voltage flexible interconnection equipment;

[0007] Construct a DC power flow type two-layer planning model, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the selected access location plan of the low voltage flexible interconnection equipment as input, and outputs the access plan of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access plan of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index;

[0008] The candidate access location plan is input into the DC power flow type double-layer planning model, and the DC power flow type double-layer planning model is solved to obtain the optimal configuration plan of the flexible interconnection device.

[0009] The classification of the low voltage substations includes: load intensive substations, resource intensive substations, load general substations and resource general substations.

[0010] The principle of flexible interconnection division of the substations is as follows:

[0011] Screening load-intensive areas and resource-intensive areas in the distribution network, and determining whether the distance between the load-intensive areas and the resource-intensive areas exceeds a distance threshold;

[0012] If the distance between the load-intensive area and the resource-intensive area does not exceed the distance threshold, flexibly interconnecting the load-intensive area and the resource-intensive area;

[0013] If the distance between the load-intensive area and the resource-intensive area exceeds a distance threshold, the load-intensive area is flexibly interconnected with a plurality of resource-general areas located near the load-intensive area, and the resource-intensive area is flexibly interconnected with a plurality of load-general areas located near the resource-intensive area;

[0014] Screen adjacent general load substations and general resource substations to determine whether the adjacent general load substations and general resource substations are not flexibly interconnected with other substations;

[0015] If adjacent general load substations and general resource substations are not flexibly interconnected with other substations, the adjacent general load substations and general resource substations shall be flexibly interconnected.

[0016] The objective function f of the medium and low voltage flexible interconnection equipment planning model 外 Expressed as: minf 外=λ1f1+λ2f2+λ3f3, where λ1, λ2 and λ3 are all index weights, and f1 is the system operation economic index, expressed as: f1=c S *S SOP +c F *S FID +C G -C S +C LOSS , c S is the equivalent annual cost per unit capacity of the soft switch equipment over its entire life cycle, S SOP is the total installed capacity of soft switches in the distribution network, c F is the equivalent annual cost per unit capacity of the flexible interconnection equipment over its entire life cycle, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, C G is the cost of energy interaction between the distribution network and the upper power grid, C S is the revenue of the distribution network from selling electricity to users, C LOSS is the cost of network loss in the distribution network; f2 is the system power supply capacity index, expressed as: T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N′ L is the total number of branches in the system, I lmax is the upper limit of the current in branch ij, I ij,t is the effective value of the current of branch ij at time t; f3 is the power quality index, expressed as: N is the total number of nodes in the system; V i,t is the voltage value of node i at time t, V i,ref is the rated voltage of node i.

[0017] The constraints of the medium and low voltage flexible interconnection equipment planning model include:

[0018] The number of low-voltage flexible interconnection devices connected and the single-point access capacity constraints are expressed as: Among them, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, N FID is the number of flexible interconnected devices in the distribution network, S F is the installation capacity of a single flexible interconnection device, N FID,max is the upper limit of the number of flexible interconnected devices allowed to be connected to the distribution network, S FID,max The maximum capacity that can be installed on a single flexible interconnection device;

[0019] The number of medium-voltage soft switchgear connected and the single-point access capacity constraints are expressed as: Among them, S SOP is the total installed capacity of soft switches in the distribution network, NSOP is the number of soft switch devices in the distribution network, S S is the installation capacity of a single soft switch device, N SOP,max is the upper limit of the number of soft switch devices allowed to be connected to the distribution network, S SOP,max The maximum capacity that can be installed for a single soft switching device.

[0020] The objective function f of the distribution network optimization operation model is 内 It is expressed as: Among them, I ij,t is the effective value of the current in branch ij at time t, R ij is the resistance of branch ij; is the active power loss value of the i-th soft switch at time t; is the active power loss value of the i-th flexible interconnected device at time t; T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N SOP is the number of soft switch devices in the distribution network, N FID is the number of flexible interconnected devices in the distribution network.

[0021] The constraints of the distribution network optimization operation model include:

[0022] The soft switching operation constraints are expressed as: in, is the active power transmitted by the port connected to the soft switch and node i at time t, is the active power transmitted by the port connected to the soft switch and node j at time t; is the active power loss value of the soft switch connected to node i at time t; is the active power loss value of the soft switch connected to node j at time t; is the loss coefficient of the soft-switching converter connected at node i, is the loss coefficient of the soft-switching converter connected at node j, is the reactive power transmitted by the soft switch connected to the port of node i at time t, is the reactive power transmitted by the port connected to the soft switch and node j at time t; i and σ j are the access states of the soft switches at nodes i and j respectively; S S The installed capacity of a single soft switch device;

[0023] The operating constraints of the flexible interconnection device are expressed as: in, is the active power transmitted by the port connected to the flexible interconnection device and node i at time t, is the active power transmitted by the port connected to the flexible interconnection device and node j at time t; is the active power loss value of the flexible interconnection device connected to node i at time t; is the active power loss value of the flexible interconnection device connected to node j at time t; is the converter loss coefficient of the flexible interconnection device connected at node i, is the converter loss coefficient of the flexible interconnection device connected at node j, is the reactive power transmitted by the port connected to the flexible interconnection device and node i at time t, is the reactive power transmitted by the port connected to the flexible interconnection device and node j at time t; η i and η j are the access status of the flexible interconnection devices at node i and node j respectively; S F The installed capacity of a single flexible interconnect device;

[0024] Line power flow constraint, expressed as: Among them, P ij,t and Q ij,t They represent the active power and reactive power flowing through branch ij at time t respectively; B i is the set of child nodes of node i; and are the active power and reactive power injected into node i at time t respectively; and are the active power of distributed energy and load in the area at node i at time t respectively; is the reactive power of the load in the substation at node i at time t;

[0025] The node voltage constraint is expressed as: Among them, V ui and V li are the voltage upper limit and voltage lower limit of node i respectively; V i b is the reference value of the voltage amplitude at node i; ΔV i,t is the correction value of the voltage amplitude at node i; ΔS i,t is the correction amount of the power injected into node i, is the element of the system admittance matrix, ΔV is the node voltage correction vector, ΔS is the node injection power correction vector, A S are parameters determined based on the system admittance matrix.

[0026] The parameters and voltage values ​​in the node voltage constraint are calculated by improving the DC power flow equation, as follows:

[0027] According to the line flow constraints, the power distribution of each branch and the node injection power are approximately calculated, and the Back-calculate the voltage phase of each node, where θ i and θ j are the voltage phase angles of node i and node j, x ij and r ij are the reactance and resistance of branch ij respectively, P ij and Q ij are the active power and reactive power flowing through branch ij respectively, θ0 is the phase angle of the source node;

[0028] The voltage of node i and the system admittance matrix are expressed as: Among them, V i is the voltage at node i, ΔV i is the voltage correction value of node i, Y + is the system admittance matrix, Y * is the system admittance matrix coefficient matrix, θ is the phase angle difference matrix;

[0029] Will Substituting into the distribution network power flow equation and ignoring the second-order small quantity, we get: Among them, V b is the node voltage amplitude reference value vector, S is the node injection power vector;

[0030] Based on diag[ΔV]·Y + ·V b =diag[Y + ·V b ]·ΔV, we get ΔS=A S ΔV, where A S =diag[Y + ·V b ]+diag[V b ]·Y + .

[0031] The step of inputting the candidate access location plan into the DC power flow type two-layer programming model and solving the DC power flow type two-layer programming model to obtain the optimal configuration plan for the flexible interconnection device specifically includes:

[0032] Inputting the candidate access location plan into the DC power flow type two-layer planning model, and using a heuristic optimization algorithm to solve the medium and low voltage flexible interconnection device planning model to obtain an access plan for soft switches and flexible interconnection devices;

[0033] Inputting the access scheme of the soft switch and the flexible interconnection device into the distribution network optimization operation model, and solving the distribution network optimization operation model using a commercial solver to obtain distribution network operation indicators;

[0034] The distribution network operation index is input into the medium and low voltage flexible interconnection device planning model, and the fitness value is calculated using the fitness function of the heuristic optimization algorithm. If the number of iterations is not reached, the access plan of the soft switch and the flexible interconnection device is updated according to the obtained fitness value, and the previous step is returned until the number of iterations is reached.

[0035] The technical solution adopted by the present invention to solve the technical problem is: to provide a medium and low voltage coordinated flexible interconnection equipment planning device, comprising:

[0036] The candidate scheme generation module is used to analyze the source-load characteristics of each low-voltage area in the distribution network, classify each low-voltage area based on the analysis results, and then generate the candidate access location scheme of the low-voltage flexible interconnection equipment according to the principle of flexible interconnection division of the area;

[0037] A model building module is used to build a DC power flow type two-layer planning model, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the low voltage flexible interconnection equipment to-be-selected access location plan as input, and outputs the access plan of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access plan of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index;

[0038] The model solving module is used to input the candidate access location plan into the DC power flow type double-layer planning model, and solve the DC power flow type double-layer planning model to obtain the optimal configuration plan of the flexible interconnection device.

[0039] The technical solution adopted by the present invention to solve its technical problem is: to provide an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above-mentioned method for planning flexible interconnected devices with medium and low voltage collaboration when executing the computer program.

[0040] The technical solution adopted by the present invention to solve its technical problem is: providing a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above-mentioned medium and low voltage collaborative flexible interconnection device planning method are implemented.

[0041] Beneficial Effects

[0042] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: the present invention divides low-voltage stations into different types, analyzes the source-load complementarity between them, and uses this as an alternative for flexible interconnection equipment planning. Compared with the existing methods, the present invention can significantly reduce the number of flexible interconnection alternative positions and reduce the complexity of the model. The present invention proposes an improved DC flow type two-layer planning model for medium and low voltage coordinated flexible interconnection equipment, which solves the complex model in layers and approximates the linearization of the inner optimization operation nonlinear constraints through the improved DC flow algorithm, which greatly improves the solution speed of the model while ensuring accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a topological diagram of a distribution network in a first embodiment of the present invention;

[0044] Figure 2 is a flow chart of a method for planning low-voltage collaborative flexible interconnected devices in a first embodiment of the present invention;

[0045] Figure 3 It is a flow chart for solving the DC power flow type two-level programming model in the first embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0047] The first embodiment of the present invention relates to a method for planning medium and low voltage coordinated flexible interconnection equipment, which can be applied to Figure 1 The distribution network topology shown in the figure first considers the different source-load characteristics between low-voltage substations, divides the low-voltage substations into different types, and analyzes the source-load complementarity between substations of different load types as a candidate for the planning of low-voltage substation interconnection equipment and a reference for the planning of low-voltage flexible interconnection equipment, so as to reduce the complexity of the model. On this basis, a two-layer planning model is proposed, in which the decision variables of the outer model are the installation location and installation capacity of medium and low voltage flexible interconnection equipment, and the objective function is the optimization of system operation economy, power supply capacity and power quality; the decision variables of the inner model are the power of flexible interconnection equipment and various distribution network operation control variables, and the goal is to minimize the loss of the distribution network under this configuration, thereby optimizing the system. Figure 2 As shown, the method for planning medium and low voltage coordinated flexible interconnection equipment in this embodiment specifically includes the following steps:

[0048] Step 1: Analyze the source-load characteristics of each low-voltage substation in the distribution network, and classify each low-voltage substation based on the analysis results. Then, based on the principle of flexible interconnection division of substations, generate a plan for the selected access location of low-voltage flexible interconnection equipment.

[0049] In this step, the low-voltage areas are divided into the following four types according to the source-load characteristics of each low-voltage area in the distribution network:

[0050] ① Load-intensive areas, such as industrial load areas and office load areas.

[0051] ② Resource-intensive substations and substations with a large surplus of distributed power generation, such as substations containing small photovoltaic power stations.

[0052] ③General load substations, substations with normal load distribution, such as residential load substations.

[0053] ④ General resource type substations, substations with slightly surplus distributed power sources, such as substations containing a certain amount of distributed power sources.

[0054] In view of the relatively short distance between low-voltage areas, this embodiment stipulates that the distance between interconnected areas shall not exceed two areas. The principles for dividing the areas with flexible interconnection in this embodiment are as follows:

[0055] Screening load-intensive areas and resource-intensive areas in the distribution network, and determining whether the distance between the load-intensive areas and the resource-intensive areas exceeds a distance threshold, that is, determining whether the distance between the load-intensive areas and the resource-intensive areas exceeds two areas;

[0056] If the distance between the load-intensive area and the resource-intensive area does not exceed the distance threshold, flexibly interconnecting the load-intensive area and the resource-intensive area;

[0057] If the distance between the load-intensive area and the resource-intensive area exceeds a distance threshold, the load-intensive area is flexibly interconnected with a plurality of resource-general areas located near the load-intensive area, and the resource-intensive area is flexibly interconnected with a plurality of load-general areas located near the resource-intensive area;

[0058] Screen adjacent general load substations and general resource substations to determine whether the adjacent general load substations and general resource substations are not flexibly interconnected with other substations;

[0059] If adjacent general load substations and general resource substations are not flexibly interconnected with other substations, the adjacent general load substations and general resource substations shall be flexibly interconnected.

[0060] The above method can obtain a solution for the candidate access locations of low-voltage flexible interconnection devices.

[0061] Step 2, construct a DC power flow type two-layer planning model, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the selected access location plan of the low voltage flexible interconnection equipment as input, and outputs the access plan of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access plan of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index.

[0062] In this step, the medium- and low-voltage flexible interconnection equipment planning model takes the installation location and installation capacity of the medium-voltage SOP and low-voltage FID connected to the medium- and low-voltage distribution network as optimization decision variables, with the system operation economy, system power supply capacity and power quality optimization as the goal. Its objective function f 外 It is expressed as:

[0063] minf 外 =λ1f1+λ2f2+λ3f3

[0064] Among them, λ1, λ2 and λ3 are all indicator weights, f1 is the system operation economy indicator, f2 is the system power supply capacity indicator, and f3 is the power quality indicator.

[0065] The system operation economic index f1 can be expressed as:

[0066] f1=c S *S SOP +c F *S FID +C G -C S +C LOSS

[0067] Among them, c S is the equivalent annual cost per unit capacity of the soft switch equipment over its entire life cycle, S SOP is the total installed capacity of soft switches in the distribution network, c F is the equivalent annual cost per unit capacity of the flexible interconnection equipment over its entire life cycle, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, C G is the cost of energy interaction between the distribution network and the upper power grid, C S is the revenue of the distribution network from selling electricity to users, C LOSS is the cost of network losses in the distribution network.

[0068] The power supply capacity of the distribution network is an important indicator of the stable operation of the system, which can be expressed by the branch load margin. The branch load margin refers to the ratio between the open capacity of a branch in the distribution network and the maximum capacity of the line. The larger the branch load margin, the more open the branch capacity is to meet the actual load demand, otherwise it may cause the branch to be overloaded. In this implementation, the system power supply capacity index f2 can be expressed as:

[0069]

[0070] Among them, T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N′ L is the total number of branches in the system, I lmax is the upper limit of the current in branch ij, I ij,t is the effective value of the current in branch ij at time t.

[0071] The voltage deviation rate is an important indicator for measuring the power quality of the distribution network, and can be represented by the comprehensive voltage deviation rate of the distribution network. In this embodiment, the power quality indicator f3 can be expressed as:

[0072]

[0073] Where N is the total number of nodes in the system; V i,t is the voltage value of node i at time t, V i,ref is the rated voltage of node i.

[0074] The constraints of the medium and low voltage flexible interconnection equipment planning model in this implementation include the number of low voltage flexible interconnection equipment access and single point access capacity constraints and the number of medium voltage soft switch equipment access and single point access capacity constraints.

[0075] The number of low-voltage flexible interconnection devices connected and the single-point access capacity constraints can be expressed as:

[0076]

[0077] Among them, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, N FID is the number of flexible interconnected devices in the distribution network, S F is the installation capacity of a single flexible interconnection device, N FID,max is the upper limit of the number of flexible interconnected devices allowed to be connected to the distribution network, S FID,max The maximum capacity that can be installed on a single flexible interconnect device.

[0078] The number of medium-voltage soft switchgear connected and the single-point access capacity constraints can be expressed as:

[0079]

[0080] Among them, S SOP is the total installed capacity of soft switches in the distribution network, N SOP is the number of soft switch devices in the distribution network, S S is the installation capacity of a single soft switch device, N SOP,max is the upper limit of the number of soft switch devices allowed to be connected to the distribution network, S SOP,max The maximum capacity that can be installed for a single soft switching device.

[0081] In this implementation, the distribution network optimization operation model selects medium and low voltage flexible interconnection equipment and distribution network operation control variables as decision variables, with the goal of minimizing system operation network loss. Its objective function f 内 It can be expressed as:

[0082]

[0083] Among them, I ij,t is the effective value of the current in branch ij at time t, R ij is the resistance of branch ij; is the active power loss value of the i-th soft switch at time t; is the active power loss value of the i-th flexible interconnected device at time t; T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N SOP is the number of soft switch devices in the distribution network, N FID is the number of flexible interconnected devices in the distribution network.

[0084] The constraints of the distribution network optimization operation model include soft switch operation constraints, flexible interconnection equipment operation constraints, line flow constraints, and node voltage constraints.

[0085] The soft switching operation constraints can be expressed as:

[0086]

[0087] in, is the active power transmitted by the port connected to the soft switch and node i at time t, is the active power transmitted by the port connected to the soft switch and node j at time t; is the active power loss value of the soft switch connected to node i at time t; is the active power loss value of the soft switch connected to node j at time t; is the loss coefficient of the soft-switching converter connected at node i, is the loss coefficient of the soft-switching converter connected at node j, is the reactive power transmitted by the soft switch connected to the port of node i at time t, is the reactive power transmitted by the port connected to the soft switch and node j at time t; i and σ j are the access status of the soft switch at node i and node j respectively, which is a 0-1 variable. When the value is "0", it means that the node is not connected to SOP, and when the value is "1", it means that the node is connected to SOP; S S The installed capacity of a single soft switching device.

[0088] The operation constraints of flexible interconnection devices can be expressed as:

[0089]

[0090] in, is the active power transmitted by the port connected to the flexible interconnection device and node i at time t, is the active power transmitted by the port connected to the flexible interconnection device and node j at time t; is the active power loss value of the flexible interconnection device connected to node i at time t; is the active power loss value of the flexible interconnection device connected to node j at time t; is the converter loss coefficient of the flexible interconnection device connected at node i, is the converter loss coefficient of the flexible interconnection device connected at node j, is the reactive power transmitted by the port connected to the flexible interconnection device and node i at time t, is the reactive power transmitted by the port connected to the flexible interconnection device and node j at time t; η i and η j are the access status of the flexible interconnection device at node i and node j respectively. They are 0-1 variables. When the value is "0", it means that the node is not connected to FID. When the value is "1", it means that the node is connected to FID. F The installed capacity of a single flexible interconnect device.

[0091] The line power flow constraint can be expressed as:

[0092]

[0093] Among them, P ij,t and Q ij,t They represent the active power and reactive power flowing through branch ij at time t respectively; B i is the set of child nodes of node i; and are the active power and reactive power injected into node i at time t respectively; and are the active power of distributed energy and load in the area at node i at time t respectively; is the reactive power of the load on node i at time t.

[0094] The node voltage constraint can be expressed as:

[0095]

[0096] Among them, V ui and V li are the voltage upper limit and voltage lower limit of node i respectively; V i b is the reference value of the voltage amplitude at node i; ΔV i,t is the correction value of the voltage amplitude at node i; ΔS i,t is the correction amount of the power injected into node i, is the element of the system admittance matrix, ΔV is the node voltage correction vector, ΔS is the node injection power correction vector, A S are parameters determined based on the system admittance matrix.

[0097] In this implementation, the parameters and voltage values ​​in the node voltage constraints can be calculated by improving the DC power flow equation. Based on the improved DC power flow algorithm, the constraint parameters of the inner model are calculated, and the inner nonlinear constraints can be approximately linearized. The specific method is as follows:

[0098] For radial medium and low voltage distribution networks, the power flow distribution of each branch and the node injection power are first approximately calculated according to the line power flow constraints, and then the voltage phase of each node can be back-substituted by the following linear equation:

[0099]

[0100] Where: θ i and θ j are the voltage phase angles of node i and node j, x ij and r ij are the reactance and resistance of branch ij respectively, P ij and Q ij are the active power and reactive power flowing through branch ij, respectively, and θ0 is the phase angle of the source node. In addition, the voltage and system admittance matrix of node i are expressed as follows:

[0101]

[0102] Where V i is the voltage at node i, ΔV i is the voltage correction value of node i, Y + is the system admittance matrix, Y *is the system admittance matrix coefficient matrix, θ is the phase angle difference matrix, and the system admittance matrix Y + Internal elements is the element of the system admittance matrix coefficient matrix. Substituting the above formula into the conventional power flow equation of the distribution network and ignoring the second-order small quantity, the following equation can be obtained:

[0103]

[0104] Where V b is the node voltage amplitude reference value vector, S is the node injection power vector. And because diag[ΔV]·Y + ·V b =diag[Y + ·V b ]·ΔV, substituting into the above formula, we can get:

[0105] ΔS=A S ΔV

[0106] In the formula, A S =diag[Y + ·V b ]+diag[V b ]·Y + , which is the key parameter in the node voltage constraint. The real part of the above node voltage correction is taken as the correction of the actual voltage, so as to obtain the amplitude and phase of the voltage of each node in the distribution network.

[0107] Step 3: Input the candidate access location plan into the DC power flow type two-layer programming model, and solve the DC power flow type two-layer programming model to obtain the optimal configuration plan for the flexible interconnection device. Figure 3 As shown, specifically:

[0108] Inputting the candidate access location plan into the DC power flow type two-layer planning model, and using a heuristic optimization algorithm to solve the medium and low voltage flexible interconnection device planning model to obtain an access plan for soft switches and flexible interconnection devices;

[0109] The access scheme of the soft switch and the flexible interconnection device is input into the distribution network optimization operation model. Since the inner nonlinear constraint is approximately linearized in this embodiment, a commercial solver can be directly used for solving. In this embodiment, the Gurobi commercial solver is used to solve the distribution network optimization operation model to obtain the distribution network operation index.

[0110] The distribution network operation index is input into the medium and low voltage flexible interconnection device planning model, and the fitness value is calculated using the fitness function of the heuristic optimization algorithm. If the number of iterations is not reached, the access plan of the soft switch and the flexible interconnection device is updated according to the obtained fitness value, and the previous step is returned until the number of iterations is reached.

[0111] It is not difficult to find that the present invention can significantly reduce the number of flexible interconnection alternative positions and reduce the complexity of the model by dividing low-voltage stations into different types and analyzing the source-load complementarity between them, and taking this as the basis for alternative solutions for flexible interconnection equipment planning. The present invention proposes a two-layer planning model for improved DC power flow type of medium and low voltage coordinated flexible interconnection equipment, which solves the complex model in layers and approximates linearization of the nonlinear constraints of the inner optimization operation through an improved DC power flow algorithm, which greatly improves the solution speed of the model while ensuring accuracy.

[0112] The second embodiment of the present invention relates to a medium and low voltage coordinated flexible interconnection equipment planning device, comprising:

[0113] The candidate scheme generation module is used to analyze the source-load characteristics of each low-voltage area in the distribution network, classify each low-voltage area based on the analysis results, and then generate the candidate access location scheme of the low-voltage flexible interconnection equipment according to the principle of flexible interconnection division of the area;

[0114] A model building module is used to build a DC power flow type two-layer planning model, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the low voltage flexible interconnection equipment to-be-selected access location plan as input, and outputs the access plan of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access plan of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index;

[0115] The model solving module is used to input the candidate access location plan into the DC power flow type double-layer planning model, and solve the DC power flow type double-layer planning model to obtain the optimal configuration plan of the flexible interconnection device.

[0116] The classification of the low voltage substations includes: load intensive substations, resource intensive substations, load general substations and resource general substations.

[0117] The principle of flexible interconnection division of the substations is as follows:

[0118] Screening load-intensive areas and resource-intensive areas in the distribution network, and determining whether the distance between the load-intensive areas and the resource-intensive areas exceeds a distance threshold;

[0119] If the distance between the load-intensive area and the resource-intensive area does not exceed the distance threshold, flexibly interconnecting the load-intensive area and the resource-intensive area;

[0120] If the distance between the load-intensive area and the resource-intensive area exceeds a distance threshold, the load-intensive area is flexibly interconnected with a plurality of resource-general areas located near the load-intensive area, and the resource-intensive area is flexibly interconnected with a plurality of load-general areas located near the resource-intensive area;

[0121] Screen adjacent general load substations and general resource substations to determine whether the adjacent general load substations and general resource substations are not flexibly interconnected with other substations;

[0122] If adjacent general load substations and general resource substations are not flexibly interconnected with other substations, the adjacent general load substations and general resource substations shall be flexibly interconnected.

[0123] The objective function f of the medium and low voltage flexible interconnection equipment planning model constructed by the model building module is 外 Expressed as: minf 外 =λ1f1+λ2f2+λ3f3, where λ1, λ2 and λ3 are all index weights, and f1 is the system operation economic index, expressed as: f1=c S *S SOP +c F *S FID +C G -C S +C LOSS , c S is the equivalent annual cost per unit capacity of the soft switch equipment over its entire life cycle, S SOP is the total installed capacity of soft switches in the distribution network, c F is the equivalent annual cost per unit capacity of the flexible interconnection equipment over its entire life cycle, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, C G is the cost of energy interaction between the distribution network and the upper power grid, C S is the revenue of the distribution network from selling electricity to users, C LOSS is the cost of network loss in the distribution network; f2 is the system power supply capacity index, expressed as: T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N′L is the total number of branches in the system, I lmax is the upper limit of the current in branch ij, I ij,t is the effective value of the current of branch ij at time t; f3 is the power quality index, expressed as: N is the total number of nodes in the system; V i,t is the voltage value of node i at time t, V i,ref is the rated voltage of node i.

[0124] The constraints of the medium and low voltage flexible interconnection equipment planning model constructed by the model construction module include:

[0125] The number of low-voltage flexible interconnection devices connected and the single-point access capacity constraints are expressed as: Among them, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, N FID is the number of flexible interconnected devices in the distribution network, S F is the installation capacity of a single flexible interconnection device, N FID,max is the upper limit of the number of flexible interconnected devices allowed to be connected to the distribution network, S FID,max The maximum capacity that can be installed on a single flexible interconnection device;

[0126] The number of medium-voltage soft switchgear connected and the single-point access capacity constraints are expressed as: Among them, S SOP is the total installed capacity of soft switches in the distribution network, N SOP is the number of soft switch devices in the distribution network, S S is the installation capacity of a single soft switch device, N SOP,max is the upper limit of the number of soft switch devices allowed to be connected to the distribution network, S SOP,max The maximum capacity that can be installed for a single soft switching device.

[0127] The objective function f of the distribution network optimization operation model constructed by the model construction module is 内 It is expressed as: Among them, I ij,t is the effective value of the current in branch ij at time t, R ij is the resistance of branch ij; is the active power loss value of the i-th soft switch at time t; is the active power loss value of the i-th flexible interconnected device at time t; T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N SOP is the number of soft switch devices in the distribution network, N FID is the number of flexible interconnected devices in the distribution network.

[0128] The constraints of the distribution network optimization operation model constructed by the model construction module include:

[0129] The soft switching operation constraints are expressed as: in, is the active power transmitted by the port connected to the soft switch and node i at time t, is the active power transmitted by the port connected to the soft switch and node j at time t; is the active power loss value of the soft switch connected to node i at time t; is the active power loss value of the soft switch connected to node j at time t; is the loss coefficient of the soft-switching converter connected at node i, is the loss coefficient of the soft-switching converter connected at node j, is the reactive power transmitted by the soft switch connected to the port of node i at time t, is the reactive power transmitted by the port connected to the soft switch and node j at time t; i and σ j are the access states of the soft switches at nodes i and j respectively; S S The installed capacity of a single soft switch device;

[0130] The operating constraints of the flexible interconnection device are expressed as: in, is the active power transmitted by the port connected to the flexible interconnection device and node i at time t, is the active power transmitted by the port connected to the flexible interconnection device and node j at time t; is the active power loss value of the flexible interconnection device connected to node i at time t; is the active power loss value of the flexible interconnection device connected to node j at time t; is the converter loss coefficient of the flexible interconnection device connected at node i, is the converter loss coefficient of the flexible interconnection device connected at node j, is the reactive power transmitted by the port connected to the flexible interconnection device and node i at time t, is the reactive power transmitted by the port connected to the flexible interconnection device and node j at time t; η i and η j are the access status of the flexible interconnection devices at node i and node j respectively; S F The installed capacity of a single flexible interconnect device;

[0131] Line power flow constraint, expressed as: Among them, P ij,t and Q ij,t They represent the active power and reactive power flowing through branch ij at time t respectively; B iis the set of child nodes of node i; and are the active power and reactive power injected into node i at time t respectively; and are the active power of distributed energy and load in the area at node i at time t respectively; is the reactive power of the load in the substation at node i at time t;

[0132] The node voltage constraint is expressed as: Among them, V ui and V li are the voltage upper limit and voltage lower limit of node i respectively; V i b is the reference value of the voltage amplitude at node i; ΔV i,t is the correction value of the voltage amplitude at node i; ΔS i,t is the correction amount of the power injected into node i, is the element of the system admittance matrix, ΔV is the node voltage correction vector, ΔS is the node injection power correction vector, A S are parameters determined based on the system admittance matrix.

[0133] The parameters and voltage values ​​in the node voltage constraint are calculated by improving the DC power flow equation, as follows:

[0134] According to the line flow constraints, the power distribution of each branch and the node injection power are approximately calculated, and the Back-calculate the voltage phase of each node, where θ i and θ j are the voltage phase angles of node i and node j, x ij and r ij are the reactance and resistance of branch ij respectively, P ij and Q ij are the active power and reactive power flowing through branch ij respectively, θ0 is the phase angle of the source node;

[0135] The voltage of node i and the system admittance matrix are expressed as: Among them, V i is the voltage at node i, ΔV i is the voltage correction value of node i, Y + is the system admittance matrix, Y * is the system admittance matrix coefficient matrix, θ is the phase angle difference matrix;

[0136] Will Substituting into the distribution network power flow equation and ignoring the second-order small quantity, we get: Among them, V bis the node voltage amplitude reference value vector, S is the node injection power vector;

[0137] Based on diag[ΔV]·Y + ·V b =diag[Y + ·V b ]·ΔV, we get ΔS=A S ΔV, where A S =diag[Y + ·V b ]+diag[V b ]·Y + .

[0138] The model solving module includes:

[0139] A first solving unit is used to input the to-be-selected access location plan into the DC power flow type two-layer planning model, and use a heuristic optimization algorithm to solve the medium and low voltage flexible interconnection device planning model to obtain an access plan for a soft switch and a flexible interconnection device;

[0140] A second solving unit is used to input the access scheme of the soft switch and the flexible interconnection device into the distribution network optimization operation model, and solve the distribution network optimization operation model using a commercial solver to obtain a distribution network operation index;

[0141] An iteration unit is used to input the distribution network operation index into the medium and low voltage flexible interconnection device planning model, and use the fitness function of the heuristic optimization algorithm to calculate the fitness value. If the number of iterations is not reached, the access plan of the soft switch and the flexible interconnection device is updated according to the obtained fitness value, and the second solution unit is returned until the number of iterations is reached.

[0142] It is not difficult to find that the present invention starts from the source-load characteristics of the substation, is closer to the actual operation of the distribution network, makes the planning scheme more scientific and practical, and realizes the flexible interconnection of medium and low voltage by deeply exploring the complementarity of source and load in the distribution network, which is in line with the development trend of flexible distribution network and has stronger foresight.

[0143] A third embodiment of the present invention relates to an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for planning flexible interconnected devices with medium and low voltage collaboration of the first embodiment when executing the computer program.

[0144] The fourth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method for planning medium and low voltage coordinated flexible interconnected devices of the first embodiment are implemented.

[0145] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0146] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0147] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction method, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0148] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0149] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for planning medium and low voltage coordinated flexible interconnection equipment, characterized in that: The following steps are involved: Analyze the source-load characteristics of each low-voltage area in the distribution network, and classify each low-voltage area based on the analysis results. Then, based on the principle of flexible interconnection division of the substation area, a plan for the selected access locations of low-voltage flexible interconnection equipment is generated; A DC power flow type two-layer planning model is constructed, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the candidate access location scheme of the low voltage flexible interconnection equipment as input, and outputs the access scheme of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access scheme of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index; the candidate access location scheme is input into the DC power flow type two-layer planning model, and the DC power flow type two-layer planning model is solved to obtain the optimal configuration scheme of the flexible interconnection equipment.

2. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1 is characterized in that: The classification of the low voltage substations includes: load intensive substations, resource intensive substations, load general substations and resource general substations.

3. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 2 is characterized in that: The principle of flexible interconnection division of the substations is as follows: Screening load-intensive areas and resource-intensive areas in the distribution network, and determining whether the distance between the load-intensive areas and the resource-intensive areas exceeds a distance threshold; If the distance between the load-intensive area and the resource-intensive area does not exceed the distance threshold, flexibly interconnecting the load-intensive area and the resource-intensive area; If the distance between the load-intensive area and the resource-intensive area exceeds a distance threshold, the load-intensive area is flexibly interconnected with a plurality of resource-general areas located near the load-intensive area, and the resource-intensive area is flexibly interconnected with a plurality of load-general areas located near the resource-intensive area; Screen adjacent general load substations and general resource substations to determine whether the adjacent general load substations and general resource substations are not flexibly interconnected with other substations; If adjacent general load substations and general resource substations are not flexibly interconnected with other substations, the adjacent general load substations and general resource substations shall be flexibly interconnected.

4. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1 is characterized in that: The objective function f of the medium and low voltage flexible interconnection equipment planning model 外 Expressed as: minf 外 =λ1f1+λ2f2+λ3f3, where λ1, λ2 and λ3 are all index weights, and f1 is the system operation economic index, expressed as: f1=c S *S SOP +c F *S FID +C G -C S +C LOSS , c S is the equivalent annual cost per unit capacity of the soft switch equipment over its entire life cycle, S SOP is the total installed capacity of soft switches in the distribution network, c F is the equivalent annual cost per unit capacity of the flexible interconnection equipment over its entire life cycle, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, C G is the cost of energy interaction between the distribution network and the upper power grid, C S is the revenue of the distribution network from selling electricity to users, C LOSS is the cost of network loss in the distribution network; f2 is the system power supply capacity index, expressed as: T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N′ L is the total number of branches in the system, I lmax is the upper limit of the current in branch ij, I ij,t is the effective value of the current of branch ij at time t; f3 is the power quality index, expressed as: N is the total number of nodes in the system; V i,t is the voltage value of node i at time t, V i,ref is the rated voltage of node i.

5. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1 is characterized in that: The constraints of the medium and low voltage flexible interconnection equipment planning model include: The number of low-voltage flexible interconnection devices connected and the single-point access capacity constraints are expressed as: Among them, S FID is the total installed capacity of flexible interconnection equipment in the distribution network, N FID is the number of flexible interconnected devices in the distribution network, S F is the installation capacity of a single flexible interconnection device, N FID,max is the upper limit of the number of flexible interconnected devices allowed to be connected to the distribution network, S FID,max The maximum capacity that can be installed on a single flexible interconnection device; The number of medium-voltage soft switchgear connected and the single-point access capacity constraints are expressed as: Among them, S SOP is the total installed capacity of soft switches in the distribution network, N SOP is the number of soft switch devices in the distribution network, S S is the installation capacity of a single soft switch device, N SOP,max is the upper limit of the number of soft switch devices allowed to be connected to the distribution network, S SOP,max The maximum capacity that can be installed for a single soft switching device.

6. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1 is characterized in that: The objective function f of the distribution network optimization operation model is 内 It is expressed as: Among them, I ij,t is the effective value of the current in branch ij at time t, R ij is the resistance of branch ij; is the active power loss value of the i-th soft switch at time t; is the active power loss value of the i-th flexible interconnected device at time t; T is the number of daily sampling points in the optimization period, N L is the set of branches in the system, N SOP is the number of soft switch devices in the distribution network, N FID is the number of flexible interconnected devices in the distribution network.

7. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1, characterized in that: The constraints of the distribution network optimization operation model include: The soft switching operation constraints are expressed as: in, is the active power transmitted by the port connected to the soft switch and node i at time t, is the active power transmitted by the port connected to the soft switch and node j at time t; is the active power loss value of the soft switch connected to node i at time t; is the active power loss value of the soft switch connected to node j at time t; is the loss coefficient of the soft-switching converter connected at node i, is the loss coefficient of the soft-switching converter connected at node j, is the reactive power transmitted by the soft switch connected to the port of node i at time t, is the reactive power transmitted by the port connected to the soft switch and node j at time t; i and σ j are the access states of the soft switches at nodes i and j respectively; S S is the installed capacity of a single soft switch device; the operation constraint of the flexible interconnection device is expressed as: in, is the active power transmitted by the port connected to the flexible interconnection device and node i at time t, is the active power transmitted by the port connected to the flexible interconnection device and node j at time t; is the active power loss value of the flexible interconnection device connected to node i at time t; is the active power loss value of the flexible interconnection device connected to node j at time t; is the converter loss coefficient of the flexible interconnection device connected at node i, is the converter loss coefficient of the flexible interconnection device connected at node j, is the reactive power transmitted by the port connected to the flexible interconnection device and node i at time t, is the reactive power transmitted by the port connected to the flexible interconnection device and node j at time t; η i and η j are the access status of the flexible interconnection devices at node i and node j respectively; S F The installed capacity of a single flexible interconnect device; Line power flow constraint, expressed as: Among them, P ij,t and Q ij,t They represent the active power and reactive power flowing through branch ij at time t respectively; B i is the set of child nodes of node i; and are the active power and reactive power injected into node i at time t respectively; and are the active power of distributed energy and load in the area at node i at time t respectively; is the reactive power of the load in the substation at node i at time t; The node voltage constraint is expressed as: Among them, V ui and V li are the voltage upper limit and voltage lower limit of node i respectively; is the reference value of the voltage amplitude at node i; ΔV i,t is the correction value of the voltage amplitude at node i; ΔS i,t is the correction amount of the power injected into node i, is the element of the system admittance matrix, ΔV is the node voltage correction vector, ΔS is the node injection power correction vector, A S are parameters determined based on the system admittance matrix.

8. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 7, characterized in that: The parameters and voltage values ​​in the node voltage constraint are calculated by improving the DC power flow equation, as follows: According to the line flow constraints, the power distribution of each branch and the node injection power are approximately calculated, and the Back-calculate the voltage phase of each node, where θ i and θ j are the voltage phase angles of node i and node j, x ij and r ij are the reactance and resistance of branch ij respectively, P ij and Q ij are the active power and reactive power flowing through branch ij respectively, θ0 is the phase angle of the source node; The voltage of node i and the system admittance matrix are expressed as: Among them, V i is the voltage at node i, ΔV i is the voltage correction value of node i, Y + is the system admittance matrix, Y * is the system admittance matrix coefficient matrix, θ is the phase angle difference matrix; Will Substituting into the distribution network power flow equation and ignoring the second-order small quantity, we get: Among them, V b is the node voltage amplitude reference value vector, S is the node injection power vector; Based on diag[ΔV]·Y + ·V b =diag[Y + ·V b ]·ΔV, we get ΔS=A S ΔV, where A S =diag[Y + ·V b ]+diag[V b ]·Y + 。 9. The method for planning medium and low voltage coordinated flexible interconnection equipment according to claim 1, characterized in that: The step of inputting the candidate access location plan into the DC power flow type two-layer programming model and solving the DC power flow type two-layer programming model to obtain the optimal configuration plan for the flexible interconnection device specifically includes: Inputting the candidate access location plan into the DC power flow type two-layer planning model, and using a heuristic optimization algorithm to solve the medium and low voltage flexible interconnection device planning model to obtain an access plan for soft switches and flexible interconnection devices; Inputting the access scheme of the soft switch and the flexible interconnection device into the distribution network optimization operation model, and solving the distribution network optimization operation model using a commercial solver to obtain distribution network operation indicators; The distribution network operation index is input into the medium and low voltage flexible interconnection device planning model, and the fitness value is calculated using the fitness function of the heuristic optimization algorithm. If the number of iterations is not reached, the access plan of the soft switch and the flexible interconnection device is updated according to the obtained fitness value, and the previous step is returned until the number of iterations is reached.

10. A medium and low voltage coordinated flexible interconnection equipment planning device, characterized in that: include: The candidate scheme generation module is used to analyze the source-load characteristics of each low-voltage area in the distribution network, classify each low-voltage area based on the analysis results, and then generate the candidate access location scheme of the low-voltage flexible interconnection equipment according to the principle of flexible interconnection division of the area; A model building module is used to build a DC power flow type two-layer planning model, wherein the outer layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a medium and low voltage flexible interconnection equipment planning model with the goal of optimizing system operation economy, system power supply capacity and power quality; the inner layer of the medium and low voltage flexible interconnection equipment two-layer planning model is a distribution network optimization operation model with the goal of minimizing system operation network loss; the medium and low voltage flexible interconnection equipment planning model takes the low voltage flexible interconnection equipment to-be-selected access location plan as input, and outputs the access plan of the soft switch and the flexible interconnection equipment; the distribution network optimization operation model takes the access plan of the soft switch and the flexible interconnection equipment as input, and outputs the distribution network operation index; The model solving module is used to input the candidate access location plan into the DC power flow type double-layer planning model, and solve the DC power flow type double-layer planning model to obtain the optimal configuration plan of the flexible interconnection device.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for planning medium and low voltage coordinated flexible interconnected devices as described in any one of claims 1-9 are implemented.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for planning medium and low voltage coordinated flexible interconnected devices as described in any one of claims 1-9 are implemented.

Images