Power distribution network flexibility resource assessment method, device, equipment, medium and program

Abstract

The invention relates to the technical field of power systems, in particular to a flexibility resource evaluation method, device and equipment of a power distribution network, a medium and a program, and the method comprises the steps: obtaining a network topology structure and network electrical characteristics of the power distribution network; determining node flexibility resources and network flexibility resources according to the network topology structure; determining an allowable adjustment range of flexibility resources of various devices in the power distribution network according to the node flexibility resources and the network electrical characteristics; determining network transmission capacities of various devices in the power distribution network according to the network flexibility resources and the network electrical characteristics; and inputting the allowable adjustment range of each device and the network transmission capacity into a maximum flow algorithm, and evaluating the target adjustment range of the flexibility resource of each node of the power distribution network based on the maximum flow algorithm. Therefore, the problems of large resource and time consumption, relatively low processing efficiency, relatively low accuracy of an evaluation result and the like of quantitative calculation of the network flexibility of the power distribution network in related technologies are solved.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a method, device, equipment, medium and program for evaluating flexibility resources of a distribution network. Background Art

[0002] Due to the limited amount of traditional fossil energy and its adverse impact on the environment, the proportion of clean energy dominated by wind and solar in the power system has increased rapidly in recent years. However, compared with traditional thermal power, wind power and photovoltaic power generation have the characteristics of uncertainty and randomness. On the other hand, the access of highly volatile loads such as electric vehicles also increases the difficulty of system operation. In order to ensure the normal operation of the new power system, the system needs to have sufficient flexibility to balance the fluctuating power supply and demand.

[0003] In terms of distribution network flexibility, there are currently a lot of studies on the balance of supply and demand of distribution network flexibility resources. Most of them adopt the method of quantifying the flexibility supply and flexibility demand of nodes to balance the supply and demand of the overall flexibility resources of the network, and on this basis, propose corresponding indicators for flexibility evaluation.

[0004] In the related technologies, the methods for evaluating the flexibility resources of distribution networks mainly include traditional power flow calculation, linear programming (LP) and mixed integer linear programming (MILP), heuristic algorithms, dynamic simulation and graph theory-based methods. However, the above methods consume a lot of resources and time, resulting in low processing efficiency and low accuracy of evaluation results. Summary of the invention

[0005] The present application provides a method, device, equipment, medium and program for evaluating the flexibility resources of a distribution network to solve the problems in the related art that the quantitative calculation of the distribution network flexibility consumes a lot of resources and time, the processing efficiency is low, and the accuracy of the evaluation results is low.

[0006] The first aspect of the present application provides a method for evaluating flexibility resources of a distribution network, comprising the following steps: obtaining a network topology and network electrical characteristics of the distribution network; determining node flexibility resources and network flexibility resources based on the network topology, wherein the node flexibility resources are used to balance the system net load fluctuations of the distribution network, and the network flexibility resources provide a transmission path for the node flexibility resources; determining an allowable adjustment range of flexibility resources of various devices in the distribution network based on the node flexibility resources and the network electrical characteristics, and determining the network transmission capacity of various devices in the distribution network based on the network flexibility resources and the network electrical characteristics; inputting the allowable adjustment range and network transmission capacity of the various devices into a maximum flow algorithm, and evaluating the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm.

[0007] Optionally, the target adjustment range of the flexibility resources of each node in the distribution network is evaluated based on the maximum flow algorithm, including: fusing the node flexibility resources and network flexibility resources to generate a directed network graph of the distribution network; identifying the network transmission capacity upper limit corresponding to each transmission path of the directed network graph, and the source points and sink points corresponding to the flexibility resources; screening augmented paths in which each transmission path has residual capacity available for circulation, calculating the minimum residual transmission capacity value on the augmented path, and updating the transmission capacity of the forward transmission path and the reverse transmission path; excluding the augmented path from the directed network graph to obtain a residual directed network graph, and iteratively updating until there are no more feasible augmented paths in the residual network, so as to determine the maximum upward flexibility resources of the flexibility resources of each node in the distribution network.

[0008] Optionally, the calculating the minimum remaining transmission capacity value on the augmented path includes: identifying whether the network transmission direction is consistent with the actual transmission direction; if the transmission directions are inconsistent, using adjacency matrix transposition.

[0009] Optionally, the node flexibility resources include: substations, energy storage and distributed generator sets, and the network flexibility resources include: lines, tie switches and flexible interconnection devices.

[0010] Optionally, the allowable adjustment range of the flexibility resources of various equipment in the distribution network is determined according to the node flexibility resources and the network electrical characteristics, including: if the node flexibility resource is a substation, the allowable adjustment range of the flexibility resources of the substation at the target time is calculated according to the power of the substation at the target time, the maximum output power and the minimum output power in the network electrical characteristics; if the node flexibility resource is energy storage, the allowable adjustment range of the flexibility resources of the energy storage at the target time is calculated according to the energy storage power, the maximum discharge power of the energy storage, the maximum charging power, the energy storage capacity, the energy storage charging and discharging efficiency, the scheduling cycle, the state of charge of the energy storage at the target time, and the maximum and minimum values ​​of the energy storage state of charge in the network electrical characteristics; if the node flexibility resource is a distributed generator set, the allowable adjustment range of the flexibility resources of the distributed generator set at the target time is calculated according to the output of distributed generation at the target time, the maximum output and minimum output of the distributed generator set in the network electrical characteristics, and the maximum upward climbing power and downward climbing power of the distributed generation.

[0011] Optionally, determining the network transmission capacity of various devices in the distribution network based on the network flexibility resources includes: determining the network transmission capacity of various devices in the distribution network based on the network flexibility resources and the network electrical characteristics includes: if the network flexibility resource is a line, then calculating the network transmission capacity between various devices at the target moment based on the maximum transmission power of the line in the network electrical characteristics and the transmission power from the first target node to the second target node at the target moment; if the network flexibility resource is a flexible interconnected device, then calculating the network transmission capacity between various devices based on the maximum transmission power of the target port in the network electrical characteristics and the transmission power of the target port at the target moment.

[0012] The second aspect of the present application provides a flexibility resource evaluation device for a distribution network, including: an acquisition module for acquiring a network topology and network electrical characteristics of the distribution network; a first processing module for determining node flexibility resources and network flexibility resources based on the network topology, wherein the node flexibility resources are used to balance the system net load fluctuations of the distribution network, and the network flexibility resources provide a transmission path for the node flexibility resources; a second processing module for determining an allowable adjustment range of flexibility resources of various devices in the distribution network based on the node flexibility resources and the network electrical characteristics, and determining the network transmission capacity of various devices in the distribution network based on the network flexibility resources and the network electrical characteristics; an evaluation module for inputting the allowable adjustment range and network transmission capacity of the various devices into a maximum flow algorithm, and evaluating the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm.

[0013] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to perform the flexibility resource assessment method for the distribution network as described in the above embodiment.

[0014] The fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to perform the flexibility resource assessment method for a distribution network as described in the above embodiment.

[0015] The fifth aspect of the present application provides a computer program product, including a computer program or instructions, characterized in that when the computer program or instructions are executed, the flexibility resource assessment method of the distribution network as described in the above embodiment is implemented.

[0016] Therefore, this application has at least the following beneficial effects:

[0017] The present application can determine the node flexibility resources and network flexibility resources according to the network topology, determine the allowable adjustment range of the flexibility resources of various devices in the distribution network according to the node flexibility resources and the network electrical characteristics, determine the network transmission capacity of various devices in the distribution network according to the network flexibility resources and the network electrical characteristics, input the allowable adjustment range and network transmission capacity of various devices into the maximum flow algorithm, and evaluate the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm. The flexibility of the distribution network can balance the fluctuating power supply and demand. The maximum flow algorithm is used to quantitatively evaluate the network flexibility of the distribution network, which can comprehensively consider the total amount of flexibility resources accessed by the distribution network, the distribution characteristics, the grid topology structure of the distribution network, and the line capacity. Factors such as line capacity improve processing efficiency and evaluation accuracy, and provide guidance for the optimized operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment.

[0018] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A flow chart of a method for evaluating flexibility resources of a distribution network provided according to an embodiment of the present application;

[0021] Figure 2 A maximum flow algorithm flow chart provided according to an embodiment of the present application;

[0022] Figure 3 A directed network graph containing multiple source nodes provided according to an embodiment of the present application;

[0023] Figure 4 A schematic diagram of a network flexibility change curve of a node provided according to an embodiment of the present application;

[0024] Figure 5 A block diagram of a flexibility resource assessment device for a distribution network provided according to an embodiment of the present application;

[0025] Figure 6 It is a schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0027] At present, the related technology (1) proposes a distribution network flexibility evaluation index system and calculation method with high penetration rate of renewable energy, and uses the flexibility deficiency rate to reflect the matching of flexibility resources and supply. The related technology (2) proposes an intelligent energy storage soft switch optimization planning considering the operation flexibility of the active distribution network, and also adopts a similar method in the related technology (1) to propose the net load regulation as an evaluation index of distribution network flexibility. However, this does not consider the impact of the network structure on the transmission of flexibility resources, resulting in low accuracy. The related technology (3) considers the distribution network optimization operation with refined modeling of flexibility resource transmission. On the basis of the node flexibility quantification model, it considers the network transmission flexibility, the ability of the line to transmit flexibility resources, and the resource loss caused by transmission, which has a better simulation effect on the actual system.

[0028] Existing research on network transmission flexibility has not achieved good results. Some studies focus on line transmission margin. Related technology (4) considers the impact of line transmission restrictions on flexibility, but does not give a specific calculation method; Related technology (5) uses line capacity margin, transformer upward capacity margin and transformer downward capacity margin as network flexibility evaluation indicators, and related technology (6) uses dynamic line evaluation technology to evaluate the transmission capacity of the line, but simply calculating the transmission margin of each line cannot quantify the flexibility loss caused by the distribution network topology and line congestion. Other studies focus on the network structure of the power system and use complex network theory or graph theory to quantify network flexibility.

[0029] In the related technology (7), while expressing flexibility by using the capacity margin of lines and transformers, node connectivity is used to evaluate the controllability of the system. In the related technology (8), the distribution network is divided into several different communities by using an improved spectral clustering detection algorithm, and the topological flexibility index of the distribution network is obtained by analyzing the degree of connection between and within communities, but the influence of electrical characteristics is not considered in the calculation. Based on complex network theory, the related technology (9) converts the distribution network into a bipartite graph, and uses the degree and electrical weighted degree to analyze the flexibility of the network, but it does not achieve a good indication effect in the example.

[0030] Therefore, this application proposes a distribution network flexibility calculation method based on the maximum flow algorithm, which can quantitatively calculate the network flexibility by comprehensively considering factors such as the electrical characteristics and topological structure of the network, and can provide guidance for the optimized operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment.

[0031] The following describes the flexibility resource evaluation method, device, electronic device, storage medium and program of the distribution network of the embodiment of the present application with reference to the accompanying drawings. In view of the problem that the quantitative calculation of the network flexibility of the distribution network in the related technology mentioned in the background technology center consumes a lot of resources and time, has low processing efficiency and low accuracy of the evaluation results, the present application provides a flexibility resource evaluation method for the distribution network, in which the node flexibility resources and network flexibility resources are determined according to the network topology structure, the allowable adjustment range of the flexibility resources of various devices in the distribution network is determined according to the node flexibility resources and the network electrical characteristics, the network transmission capacity of various devices in the distribution network is determined according to the network flexibility resources and the network electrical characteristics, the allowable adjustment range and network transmission capacity of various devices are input into the maximum flow algorithm, and the target adjustment range of the flexibility resources of each node of the distribution network is evaluated based on the maximum flow algorithm. The flexibility of the distribution network can balance the fluctuating power supply and demand, and the maximum flow algorithm is used to quantitatively evaluate the network flexibility of the distribution network, which can comprehensively consider the total amount of flexibility resources accessed by the distribution network, the distribution characteristics, and the distribution network grid topology structure and line capacity and other factors, thereby improving the processing efficiency and evaluation accuracy, and providing guidance for the optimization operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment. This solves the problems in related technologies such as the large amount of resources and time consumed in the quantitative calculation of distribution network flexibility, low processing efficiency, and low accuracy of evaluation results.

[0032] Specifically, Figure 1 A flow chart of a method for evaluating flexibility resources of a distribution network provided in an embodiment of the present application.

[0033] like Figure 1 As shown, the flexibility resource evaluation method of the distribution network includes the following steps:

[0034] In step S101, the network topology and network electrical characteristics of the power distribution network are obtained.

[0035] It can be understood that the embodiments of the present application can obtain the network topology and network electrical characteristics of the distribution network, so as to determine the node flexibility resources and network flexibility resources according to the network topology, and calculate relevant parameters according to the network electrical characteristics.

[0036] It should be noted that the network topology refers to the geometric layout of the nodes and their connections in the power system, where nodes include substations, power stations, energy storage devices, distributed power generation equipment, load points, etc. The lines or cables connecting the nodes in the network topology represent the power transmission path. Electrical characteristics refer to the electrical parameters of each component and network in the power system, which determine the operating performance and behavior of the system.

[0037] In step S102, node flexibility resources and network flexibility resources are determined according to the network topology structure, wherein the node flexibility resources are used to balance the system net load fluctuation of the distribution network, and the network flexibility resources provide a transmission path for the node flexibility resources.

[0038] Among them, node flexibility resources include: substations, energy storage and distributed generators; network flexibility resources include: lines, interconnecting switches and flexible interconnection equipment.

[0039] It can be understood that the embodiments of the present application can determine node flexibility resources and network flexibility resources based on the network topology structure. The node flexibility resources are used to balance the system net load fluctuations of the distribution network. The network flexibility resources provide a transmission path for the node flexibility resources. It can comprehensively consider multiple factors such as the distribution network grid topology structure and line capacity, thereby improving the accuracy of subsequent calculations.

[0040] It should be noted that the flexibility resources of the distribution network mainly come from the substations, energy storage and distributed generation connected to the nodes, while the flexibility demand comes from wind power, photovoltaics and loads with large fluctuations, such as electric vehicles. The flexibility adopted is defined as the ability of the system to cope with uncertain disturbances, specifically the ability to balance the net load fluctuation generated by the system at the next moment relative to the current moment. In the power system, the network structure does not directly provide flexibility resources, but expresses its own flexibility through the transmission node flexibility resources.

[0041] In step S103, the allowable adjustment range of the flexibility resources of various devices in the distribution network is determined according to the node flexibility resources and the network electrical characteristics, and the network transmission capacity of various devices in the distribution network is determined according to the network flexibility resources and the network electrical characteristics.

[0042] It can be understood that the embodiments of the present application can determine the allowable adjustment range of the flexibility resources of various devices in the distribution network based on the node flexibility resources and the network electrical characteristics, and determine the network transmission capacity of various devices in the distribution network based on the network flexibility resources and the network electrical characteristics. It can comprehensively consider multiple factors such as the distribution network grid topology structure and line capacity, and improve the accuracy of subsequent calculations.

[0043] In an embodiment of the present application, the allowable adjustment range of the flexibility resources of various equipment in the distribution network is determined based on the node flexibility resources and the network electrical characteristics, including: if the node flexibility resource is a substation, the allowable adjustment range of the flexibility resources of the substation at the target time is calculated based on the power of the substation at the target time, the maximum output power and the minimum output power in the network electrical characteristics; if the node flexibility resource is energy storage, the allowable adjustment range of the flexibility resources of the energy storage at the target time is calculated based on the energy storage power in the network electrical characteristics, the maximum discharge power of the energy storage, the maximum charging power, the energy storage capacity, the energy storage charging and discharging efficiency, the scheduling cycle, the charge state of the energy storage at the target time, and the maximum and minimum values ​​of the energy storage charge state; if the node flexibility resource is a distributed generator set, the allowable adjustment range of the flexibility resources of the distributed generator set at the target time is calculated based on the output of distributed power generation at the target time, the maximum output and minimum output of the distributed generator set in the network electrical characteristics, and the maximum upward climbing power and downward climbing power of the distributed power generation.

[0044] It can be understood that the embodiments of the present application can calculate the allowable adjustment range of the flexibility resources of various equipment in the distribution network based on the node flexibility resource type and the network electrical characteristics corresponding to the node flexibility resource type, so as to more intuitively determine the system's upward flexibility in response to an increase in net load and the downward flexibility in response to a decrease in net load, thereby improving subsequent processing efficiency.

[0045] It should be noted that the allowable adjustment range of flexibility resources includes upward flexibility and downward flexibility, among which upward flexibility responds to the increase in net load, and downward flexibility responds to the decrease in net load.

[0046] Specifically, the flexibility resources of the distribution network mainly come from the substations, energy storage and distributed generation connected to the nodes. For the above resources, the flexibility of each device is defined as follows:

[0047] (1) Substation

[0048] The distribution network obtains electricity from the upper grid through substations. The flexibility that a substation can provide depends on its maximum transmission power and the power at the current moment:

[0049]

[0050] Among them, F Sub,up,t and F Sub,dn,t are the upward and downward flexibility resources of the substation at time t, P Sub,t is the power of the substation at time t, P Sub,max and P Sub,min are the maximum and minimum output power of the substation respectively.

[0051] (2) Energy storage

[0052] Energy storage can quickly change the charge and discharge power to provide flexibility resources for the system, but it should be noted that due to the limitation of the state of charge, energy storage may change from providing flexibility resources to demanding flexibility resources during operation. For example, when the energy storage is already full and was in the charging state at the last moment, the energy storage not only cannot provide downward flexibility resources, but needs to downward adjust flexibility resources to make itself exit the charging state. This change from resources to demand can be expressed by the change of the sign of the flexibility resource:

[0053]

[0054] Among them, F ES,up,t and F ES,dn,t are the upward and downward flexibility resources of energy storage at time t, respectively, ES,t is the energy storage power, which is defined as positive during discharge and negative during charge, P dis,max and P c h ,max is the maximum discharge and maximum charging power of energy storage, E WS is the energy storage capacity, η is the energy storage charging and discharging efficiency, ΔT is the scheduling period, S oc,t is the state of charge of the energy storage at time t, S oc,max and S oc,min are the maximum and minimum values ​​of the energy storage charge state, respectively.

[0055] (3) Distributed Generation

[0056] Distributed generators can provide flexibility by changing their output, but compared to substations, the flexibility of distributed generation is limited by the ramp rate:

[0057]

[0058] Among them, F DG,up,t and F DG,dn,t are the upward and downward flexibility resources of distributed generators at time t, P DG,t is the output of distributed generation at time t, P DG,max and P DG,min are the maximum and minimum output of distributed generator sets, r up and r dn They are the maximum upward and downward climbing powers of distributed generation respectively.

[0059] In an embodiment of the present application, the network transmission capacity of various devices in the distribution network is determined based on the network flexibility resources and the network electrical characteristics, including: if the network flexibility resource is a line, the network transmission capacity between various devices at the target time is calculated based on the maximum transmission power of the line in the network electrical characteristics and the transmission power from the first target node to the second target node at the target time; if the network flexibility resource is a flexible interconnected device, the network transmission capacity between various devices is calculated based on the maximum transmission power of the target port in the network electrical characteristics and the transmission power of the target port at the target time.

[0060] It can be understood that the embodiments of the present application can determine the network transmission capacity of various devices in the distribution network based on the network flexibility resources and network electrical characteristics, thereby expressing the flexibility of each flexibility resource through the transmission node flexibility resources and improving subsequent processing efficiency.

[0061] Specifically, in the power system, the network structure does not directly provide flexibility resources, but rather demonstrates its own flexibility through transmission node flexibility resources. Network flexibility resources include lines, tie switches, and flexible interconnection devices, specifically:

[0062] (1) Line

[0063] The line can provide a channel for the transmission of flexible resources. Its transmission capacity depends on the upper limit of the line power and the current power flowing through it:

[0064] L ij,t =P ij,max -P ij,t ;

[0065] Where L ij,t is the line flexible transmission capacity from node i to node j at time t, P ij,max is the maximum transmission power of the line, P ij,t is the transmission power from node i to node j at time t,

[0066] P ij,t +P ji,t =0.

[0067] 1.2.2 Tie switch

[0068] Different combinations of tie switches can change the topology of the network, thereby changing the flow of flexibility in the network, and therefore is also a network flexibility resource.

[0069] 1.2.3 Flexible interconnection equipment

[0070] Flexible interconnection equipment can realize flexible connection of AC lines, enable closed-loop operation of distribution networks, and actively adjust line flows to regulate the flow of flexible resources. Its transmission capacity is as follows:

[0071] L SOP,in,i,t =P SOP,i,max -P SOP,i,t

[0072] L SOP,out,i,t =P SOP,i,max -P SOP,i,t

[0073] Where L SOP,in,i,t and L SOp,out,i,t are the flexible transmission capacity of the flexible interconnection device input and output from port i at time t, P SOP,i,max is the maximum transmission power of port i, P SOP,i,t is the transmission power of port i at time t, with the power entering the flexible interconnect device being positive.

[0074] In step S104, the allowable adjustment ranges of various devices and the network transmission capacity are input into the maximum flow algorithm, and the target adjustment range of the flexibility resources of each node in the distribution network is evaluated based on the maximum flow algorithm.

[0075] It can be understood that the embodiments of the present application can input the allowable adjustment range of various devices and the network transmission capacity into the maximum flow algorithm, and evaluate the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm. It can comprehensively consider the total amount of flexibility resources accessed by the distribution network, distribution characteristics, and distribution network grid topology structure and line capacity and other factors, thereby improving processing efficiency and evaluation accuracy, and providing guidance for the optimized operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment.

[0076] It should be noted that the maximum flow problem is defined as finding the maximum flow from the source to the sink in a flow network where each directed edge has a capacity constraint, without exceeding the capacity constraint of each edge. By applying the maximum flow method to flexibility evaluation, a new network flexibility index can be obtained. This index can not only represent the supply of flexibility resources in the network, but also reflect the actual transmission capacity of the network for flexibility resources, which has a good guiding role in system operation and resource allocation.

[0077] In an embodiment of the present application, a target adjustment range of flexibility resources of each node in a distribution network is evaluated based on a maximum flow algorithm, including: fusing node flexibility resources and network flexibility resources to generate a directed network graph of the distribution network; identifying the upper limit of the network transmission capacity corresponding to each transmission path of the directed network graph, and the source and sink points corresponding to the flexibility resources; screening augmented paths in which each transmission path has residual capacity available for circulation, calculating the minimum residual transmission capacity value on the augmented path, and updating the transmission capacity of the forward transmission path and the reverse transmission path; removing the augmented path from the directed network graph to obtain a residual directed network graph, and iteratively updating until there are no more feasible augmented paths in the residual network, so as to determine the maximum upward flexibility resources of the flexibility resources of each node in the distribution network.

[0078] It can be understood that the embodiments of the present application can obtain the maximum flow from the source point to the sink point in a flow network where each directed edge has a capacity limit, without exceeding the limited capacity of each edge. By applying the maximum flow method to flexibility evaluation, a new network flexibility index can be obtained, which can not only represent the supply of flexibility resources in the network, but also reflect the actual transmission capacity of the network for flexibility resources, and has a good guiding role in system operation and resource allocation.

[0079] In an embodiment of the present application, calculating the minimum remaining transmission capacity value on the augmented path includes: identifying whether the network transmission direction is consistent with the actual transmission direction; if the transmission directions are inconsistent, using adjacency matrix transposition.

[0080] It can be understood that in the embodiment of the present application, since the direction of the actual power is different from the direction of the downward adjustment of the flexibility resource flow, it is necessary to transpose the adjacency matrix to improve the calculation accuracy and processing efficiency.

[0081] Specifically, after defining the upward and downward flexibility resources of various devices and the transmission capacity of the network, the upward and downward flexibility resources that each node can obtain can be calculated in combination with the maximum flow algorithm. This can be used as an evaluation indicator of network flexibility. It combines the topological structure and electrical characteristics of the network and reflects the transmission capacity of the grid structure for flexibility resources.

[0082] like Figure 2 As shown in the figure, the basic calculation process of the maximum flow algorithm is as follows: first, select a capacity upper limit for each edge of the network, and then determine the source and sink points; find a path in the original network in which each edge has residual capacity for flow, take the flow of this path as the current maximum flow value, and remove it from the original network to obtain the residual network, and then perform the above operations on the residual network until there are no feasible augmenting paths in the residual network.

[0083] Based on the node flexibility and network flexibility, the maximum flow method is used to obtain the maximum upward and downward flexibility resources that each node can obtain as the network flexibility index. First, create a directed flow network of the distribution network, such as Figure 3 As shown, its adjacency matrix is

[0084]

[0085] That is, the capacity of the directed edge (i, j) is L ij,t , the capacity of the directed edge (j,i) is L ji,t . Secondly, the source points are set as substations, energy storage and distributed generation nodes. In the case of multiple source points, a super source node can be set to connect with each source point, and the capacity of the connecting edge is the flexibility resource amount of each source point.

[0086] The network thus obtained can be used to calculate the network flexibility index using the maximum flow algorithm. It should be noted that when calculating the downward flexibility index, the adjacency matrix needs to be transposed because the direction of the actual power is different from the direction of the downward flexibility resource flow.

[0087] H up,T,t =Maxflow(A,S,T,t)

[0088] H dn,T,t =Maxflow(A',S,T,t)

[0089] Among them, H up,T,t and H dn,T,t are the upward and downward network flexibility indicators of node T at time t, S is the set of source points, and A is the adjacency matrix composed of edge capacity.

[0090] The network flexibility index of a node indicates how much flexibility resources the node obtains in the network. This depends not only on the total amount of flexibility resources in the network, but also on the network topology, line capacity and the distribution of flexibility resources in the network. Therefore, the network flexibility evaluation method based on maximum flow proposed in this paper can reflect the size of network flexibility resources and provide an evaluation basis for how to improve the network flexibility of the system during planning and operation.

[0091] According to the flexibility resource evaluation method for a distribution network proposed in an embodiment of the present application, node flexibility resources and network flexibility resources are determined according to the network topology structure, the allowable adjustment range of the flexibility resources of various devices in the distribution network is determined according to the node flexibility resources and the network electrical characteristics, the network transmission capacity of various devices in the distribution network is determined according to the network flexibility resources and the network electrical characteristics, the allowable adjustment range and the network transmission capacity of various devices are input into the maximum flow algorithm, and the target adjustment range of the flexibility resources of each node in the distribution network is evaluated based on the maximum flow algorithm. The flexibility of the distribution network can balance the fluctuating power supply and demand. The maximum flow algorithm is used to quantitatively evaluate the network flexibility of the distribution network, and can comprehensively consider the total amount of flexibility resources accessed by the distribution network, the distribution characteristics, and the grid topology and line capacity of the distribution network, thereby improving the processing efficiency and evaluation accuracy, and providing guidance for the optimized operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment.

[0092] The following is an example of a typical network flexibility evaluation index of the present application, which is as follows:

[0093] like Figure 4 As shown in Figure 3, the network flexibility change curve of the target node is selected, where the upward network flexibility of the node is smaller at 7-8 o'clock, indicating that it cannot withstand excessive load increments during this time period; while the downward network flexibility of the node remains at a high level, which is slightly lower at 1 o'clock in the morning, indicating that the node has a strong ability to cope with a decrease in net load during most of the day, but its downward adjustment ability is slightly weaker at 1 o'clock in the morning.

[0094] In summary, this application models the node flexibility resources and network flexibility resources in the distribution network, taking into account the upward flexibility to cope with the increase in net load and the downward flexibility to cope with the decrease in net load. In the process of energy storage flexibility modeling, the possible transformation of energy storage from providing flexibility resources to demand flexibility resources is taken into account; secondly, a directed network graph based on the distribution network is constructed, and the maximum flow algorithm is used to obtain the amount of flexibility resources that can be obtained by each demand node as a network flexibility evaluation indicator.

[0095] Next, a flexibility resource assessment device for a distribution network proposed according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0096] Figure 5 It is a block diagram of a flexibility resource assessment device for a distribution network according to an embodiment of the present application.

[0097] like Figure 5 As shown, the flexibility resource assessment device 10 of the distribution network includes: an acquisition module 100, a first processing module 200, a second processing module 300 and an assessment module 400.

[0098] Among them, the acquisition module 100 is used to obtain the network topology structure and network electrical characteristics of the distribution network; the first processing module 200 is used to determine the node flexibility resources and network flexibility resources according to the network topology structure, and determine the allowable adjustment range of the flexibility resources of various devices in the distribution network according to the node flexibility resources and network electrical characteristics, wherein the node flexibility resources are used to balance the system net load fluctuations of the distribution network; the second processing module 300 is used to determine the network transmission capacity of various devices in the distribution network according to the network flexibility resources and network electrical characteristics, wherein the network flexibility resources provide a transmission path for the node flexibility resources; the evaluation module 400 is used to input the allowable adjustment range and network transmission capacity of various devices into the maximum flow algorithm, and evaluate the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm.

[0099] It should be noted that the aforementioned explanation of the embodiment of the method for evaluating the flexibility resources of a distribution network is also applicable to the device for evaluating the flexibility resources of a distribution network of this embodiment, and will not be repeated here.

[0100] According to the flexibility resource evaluation device of the distribution network proposed in the embodiment of the present application, the node flexibility resources and the network flexibility resources are determined according to the network topology structure, the allowable adjustment range of the flexibility resources of various devices in the distribution network is determined according to the node flexibility resources and the network electrical characteristics, the network transmission capacity of various devices in the distribution network is determined according to the network flexibility resources and the network electrical characteristics, the allowable adjustment range and the network transmission capacity of various devices are input into the maximum flow algorithm, and the target adjustment range of the flexibility resources of each node in the distribution network is evaluated based on the maximum flow algorithm. The flexibility of the distribution network can balance the fluctuating power supply and demand. The maximum flow algorithm is used to quantitatively evaluate the network flexibility of the distribution network, and can comprehensively consider the total amount of flexibility resources accessed by the distribution network, the distribution characteristics, and the grid topology and line capacity of the distribution network, thereby improving the processing efficiency and evaluation accuracy, and providing guidance for the optimized operation of the distribution network and the subsequent planning of flexible interconnected power electronic equipment.

[0101] Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0102] A memory 601 , a processor 602 , and a computer program stored in the memory 601 and executable on the processor 602 .

[0103] When the processor 602 executes the program, the flexibility resource evaluation method for the distribution network provided in the above embodiment is implemented.

[0104] Furthermore, the electronic device further comprises:

[0105] The communication interface 603 is used for communication between the memory 601 and the processor 602 .

[0106] The memory 601 is used to store computer programs that can be executed on the processor 602 .

[0107] The memory 601 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0108] If the memory 601, the processor 602 and the communication interface 603 are implemented independently, the communication interface 603, the memory 601 and the processor 602 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0109] Optionally, in a specific implementation, if the memory 601, the processor 602 and the communication interface 603 are integrated on a chip, the memory 601, the processor 602 and the communication interface 603 can communicate with each other through an internal interface.

[0110] The processor 602 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0111] An embodiment of the present application also provides a computer-readable storage medium having a computer program or instructions stored thereon. When the computer program or instructions are executed by a processor, the flexibility resource evaluation method of the distribution network as described above is implemented.

[0112] An embodiment of the present application also provides a computer program product, including a computer program or instructions, characterized in that when the computer program or instructions are executed, the flexibility resource assessment method of the distribution network as described above is implemented.

[0113] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0114] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0115] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0116] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of multiple of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0117] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

Claims

1. A method for evaluating the flexibility resources of a distribution network, characterized in that: The following steps are involved: Obtain the network topology and network electrical characteristics of the distribution network; Determining a node flexibility resource and a network flexibility resource according to the network topology structure, wherein the node flexibility resource is used to balance the system net load fluctuation of the distribution network, and the network flexibility resource provides a transmission path for the node flexibility resource; Determine the allowable adjustment range of the flexibility resources of various devices in the distribution network according to the node flexibility resources and the network electrical characteristics, and determine the network transmission capacity of various devices in the distribution network according to the network flexibility resources and the network electrical characteristics; The allowable adjustment ranges of the various devices and the network transmission capacity are input into a maximum flow algorithm, and the target adjustment range of the flexibility resources of each node in the distribution network is evaluated based on the maximum flow algorithm.

2. The method for evaluating the flexibility resources of a distribution network according to claim 1, characterized in that: The method of evaluating the target adjustment range of the flexibility resources of each node of the distribution network based on the maximum flow algorithm includes: Fusion of the node flexibility resources and the network flexibility resources to generate a directed network graph of the distribution network; Identify the network transmission capacity upper limit corresponding to each transmission path of the directed network graph, and the source and sink points corresponding to the flexibility resources; Screening each augmented path with remaining capacity available for circulation, calculating the minimum remaining transmission capacity value on the augmented path, and updating the transmission capacity of the forward transmission path and the reverse transmission path; The augmenting paths are removed from the directed network graph to obtain a residual directed network graph, and the graph is iteratively updated until there are no feasible augmenting paths in the residual network, so as to determine the maximum upward flexibility resources of the flexibility resources of each node in the distribution network.

3. The method for evaluating the flexibility resources of a distribution network according to claim 2, characterized in that: The calculating the minimum remaining transmission capacity value on the augmented path includes: Identify whether the network transmission direction is consistent with the actual transmission direction; If the transmission directions are inconsistent, the adjacency matrix is ​​transposed.

4. The method for evaluating the flexibility resources of a distribution network according to claim 1, characterized in that: The node flexibility resources include: substations, energy storage and distributed generator sets, and the network flexibility resources include: lines, tie switches and flexible interconnection equipment.

5. The method for evaluating the flexibility resources of a distribution network according to claim 4, characterized in that: The determining, according to the node flexibility resources and the network electrical characteristics, the allowable adjustment range of the flexibility resources of various devices in the distribution network comprises: If the node flexibility resource is a substation, the allowable adjustment range of the flexibility resource of the substation at the target time is calculated according to the power of the substation at the target time, the maximum output power and the minimum output power in the network electrical characteristics; If the node flexibility resource is energy storage, the allowable adjustment range of the flexibility resource of the energy storage at the target time is calculated based on the energy storage power, the maximum discharge power of the energy storage, the maximum charging power, the energy storage capacity, the energy storage charging and discharging efficiency, the scheduling cycle, the state of charge of the energy storage at the target time, and the maximum and minimum values ​​of the energy storage state of charge in the network electrical characteristics; If the node flexibility resource is a distributed generator set, the allowable adjustment range of the flexibility resources of the distributed generator set at the target time is calculated based on the output of distributed generation at the target time, the maximum output and minimum output of the distributed generator set in the network electrical characteristics, and the maximum upward climbing power and downward climbing power of the distributed generation.

6. The method for evaluating the flexibility resources of a distribution network according to claim 4, characterized in that: The determining the network transmission capacity of various devices in the distribution network according to the network flexibility resources and the network electrical characteristics includes: If the network flexibility resource is a line, the network transmission capacity between various devices at the target time is calculated according to the maximum transmission power of the line in the network electrical characteristics and the transmission power from the first target node to the second target node at the target time; If the network flexibility resource is a flexible interconnection device, the network transmission capacity between various devices is calculated based on the maximum transmission power of the target port in the network electrical characteristics and the transmission power of the target port at the target time.

7. A flexibility resource evaluation device for a distribution network, characterized in that: include: An acquisition module, used to acquire the network topology and network electrical characteristics of the distribution network; A first processing module is used to determine a node flexibility resource and a network flexibility resource according to the network topology structure, wherein the node flexibility resource is used to balance the system net load fluctuation of the distribution network, and the network flexibility resource provides a transmission path for the node flexibility resource; A second processing module is used to determine the allowable adjustment range of the flexibility resources of various devices in the distribution network according to the node flexibility resources and the network electrical characteristics, and determine the network transmission capacity of various devices in the distribution network according to the network flexibility resources and the network electrical characteristics; An evaluation module is used to input the allowable adjustment range of the various devices and the network transmission capacity into a maximum flow algorithm, and evaluate the target adjustment range of the flexibility resources of each node in the distribution network based on the maximum flow algorithm.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for evaluating flexibility resources of a distribution network as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, it is used to implement the flexibility resource assessment method for the distribution network as described in any one of claims 1-6.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed, the flexibility resource assessment method for the distribution network as described in any one of claims 1-6 is implemented.

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