Receiving end power grid flexibility load flow calculation method and equipment considering interconnection of sending end and receiving end, and medium

Abstract

The invention relates to a receiving-end power grid flexibility load flow calculation method and device considering transmitting-receiving end interconnection and a medium, and the method comprises the steps: building a local flexibility supply model not considering transmitting-end flexibility support and a comprehensive flexibility supply model considering transmitting-receiving end interconnection based on resource data, and calculating the node flexibility supply quantity of a receiving-end power grid; based on the prediction type data, constructing a receiving end power grid node flexibility demand model, and combining prediction errors of load and new energy output to obtain a node flexibility demand quantity; based on the network type data, the node flexibility supply and demand result is mapped to each line of the power grid through a power transmission distribution factor, and flexibility power flow distribution reflecting a flexibility resource space migration path is obtained; and calculating the flexibility transmission margin of each line so as to obtain the flexibility bearing degree representing the overall flexibility of the receiving-end power grid. Compared with the prior art, the method has the advantages of accuracy, integrity, practicability and the like.

Description

Technical Field

[0001] This invention relates to the field of power system operation and control technology, and in particular to a method, device and medium for calculating the power flow flexibility of the receiving-end power grid considering the interconnection between the sending and receiving ends. Background Technology

[0002] Receiving-end grid flexibility assessment is a key technology in the field of power system operation and control, mainly used to quantify the grid's ability to cope with fluctuations and uncertainties. With the large-scale and high-proportion integration of renewable energy into the grid, the uncertainties and fluctuations faced by the receiving-end grid are becoming increasingly prominent, placing higher demands on the accurate assessment of system flexibility.

[0003] Traditional flexibility assessment methods primarily focus on resource characteristics at the node level. For example, analyzing the ramp-up capability of thermal power units, the charging and discharging characteristics of energy storage devices, and the regulation potential of local resources such as demand-side response can reflect the system's regulation capacity to some extent. However, these methods are mostly limited to node-level supply and demand balance analysis, failing to fully consider the spatial distribution and transmission characteristics of flexibility resources within the power grid. In actual power systems, the availability of flexibility resources depends not only on their own regulation capacity but also on network transmission capacity. Due to the complexity of the power grid topology and limited line transmission capacity, surplus flexibility resources at the node level may not be effectively delivered to demand nodes, leading to discrepancies between the assessment results and the system's actual dispatchable capacity. Furthermore, existing assessment methods often lack in-depth consideration of the impact of inter-regional interconnections. In power grid structures with interconnected sending and receiving ends, inter-regional flexibility resources such as pumped storage and tie lines in the sending-end grid can provide crucial regulation support to the receiving-end grid. However, traditional methods often focus on local resources at the receiving end, failing to effectively incorporate sending-end flexibility support into the assessment system, making it difficult to comprehensively reflect the overall flexibility level under sending-receiving end collaboration.

[0004] Therefore, how to consider network transmission constraints when performing flexibility supply and demand accounting at the node level, thereby identifying the spatial migration path and potential congestion risks of flexibility resources in actual scheduling, accurately reflecting the enhancing effect of cross-regional resources on the flexibility of the receiving end, and uniformly assessing flexibility power flow and line carrying capacity, so as to timely and accurately locate system flexibility, are technical problems that need to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a method, device and medium for calculating the flexibility power flow of the receiving-end power grid that takes into account the interconnection of the sending and receiving ends. By introducing a power transmission distribution factor, the flexibility supply and demand of nodes are mapped to the flexibility power flow on the power grid lines. In the assessment, the spatial transmission path and congestion risk of flexibility resources are quantified, thereby improving the accuracy and overall quality of flexibility assessment.

[0006] The objective of this invention can be achieved through the following technical solutions: According to one aspect of the present invention, a method for calculating the power flow flexibility of a receiving-end power grid considering the interconnection between sending and receiving ends is provided, the specific steps of which include: S1. Collect operational data of the receiving-end power grid, including resource data, forecast data, and network data; S2. Based on resource-related data, establish a local flexibility supply model that takes into account the flexibility support of the sending end and a comprehensive flexibility supply model that takes into account the interconnection between the sending and receiving ends, and calculate the nodal flexibility supply of the receiving end power grid; based on forecast data, construct a nodal flexibility demand model for the receiving end power grid, and combine the forecast errors of load and renewable energy output to obtain the nodal flexibility demand; based on network-related data, map the nodal flexibility supply and demand results to each line of the power grid through the power transmission distribution factor to obtain the flexibility power flow distribution that reflects the spatial migration path of flexibility resources. S3. Calculate the flexibility transmission margin for each line based on the flexible power flow distribution and the maximum transmission capacity of the line. S4. The calculation results of the combined node flexibility supply, node flexibility demand, flexibility power flow distribution and flexibility transmission margin are used to obtain the flexibility carrying capacity, which characterizes the overall flexibility of the receiving-end power grid.

[0007] Furthermore, in S2, the specific steps for calculating node flexibility supply in the local flexibility supply model include: The input resource data includes local resource operation data, including thermal power unit operation data, energy storage equipment operation data, and demand-side response data. Thermal power unit operation data includes real-time output, technical output boundary, and ramp rate. Energy storage equipment operation data includes real-time charging and discharging power, state of charge, and power capacity of energy storage equipment. Demand-side response data includes interruptible load and real-time interruption level of demand-side response. Based on the operating data of the thermal power units, the difference between the current output and the upper limit of output is calculated and combined with the ramping capability constraint to obtain the upward flexibility supply of the current thermal power units within the dispatch interval; the difference between the current output and the lower limit of output is calculated and combined with the ramping capability constraint to obtain the downward flexibility supply of the current thermal power units within the dispatch interval. Based on the operating data of the energy storage device, the difference between the maximum discharge power and the current discharge power is calculated, and it is verified whether the state of charge is higher than the lower limit to obtain the upward flexibility supply of the current energy storage device; the difference between the maximum charging power and the current charging power is calculated, and it is verified whether the state of charge is lower than the upper limit to obtain the downward flexibility supply of the current energy storage device. Based on the demand-side response data, the difference between the maximum interruptible load and the current interrupted load is calculated to obtain the upward flexibility supply of the current demand-side response resources at the node. Based on the upward flexibility supply of thermal power units, the downward flexibility supply of thermal power units, the upward flexibility supply of energy storage equipment, the downward flexibility supply of energy storage equipment, and the upward flexibility supply of demand-side response resources, the local flexibility supply of the same node is obtained, which is the upward node flexibility supply and downward node flexibility supply of the current node without taking into account the sending-end flexibility support.

[0008] Furthermore, in S2, the specific steps for calculating node flexibility supply in the comprehensive flexibility supply model include: The cross-regional resource operation data in the input resource category includes the operation data of the sending-end pumped storage power station and the operation data of the sending-receiving end interconnection line; the operation data of the sending-end pumped storage power station includes the real-time output, power limit and reservoir capacity status of the sending-end pumped storage power station, and the operation data of the sending-receiving end interconnection line includes the real-time transmission power of the DC interconnection line between the sending and receiving ends, the real-time transmission power and power transmission limit of the AC interconnection line between the sending and receiving ends; Based on the operating data of the pumped storage power station at the sending end, the upward and downward flexible supply quantities considering the reservoir capacity constraints are calculated, and combined with the pumped storage distribution coefficient of the corresponding node at the receiving end and the real-time power of the tie line, the upward and downward flexible supply quantities transmitted to the specific node at the receiving end through the form of pumped storage distribution are obtained. Based on the operation data of the sending and receiving end tie lines, the difference between the maximum transmission power and the current transmission power of the tie line is calculated, and combined with the power up-adjustment rate constraint, the upward flexibility supply provided by the current tie line to the connected node of the receiving end is obtained; by calculating the difference between the current transmission power and the minimum transmission power, and combined with the current power down-adjustment rate constraint, the downward flexibility supply provided by the tie line to the connected node of the receiving end is obtained. The node flexibility supply transmitted through pumped storage and distribution and the node flexibility supply provided by the sending and receiving end interconnection are superimposed to obtain the current node's upward node flexibility supply and downward node flexibility supply taking into account the sending and receiving end interconnection.

[0009] Furthermore, in step S2, the specific steps for calculating the flexibility requirements of computing nodes include: Input forecast data, including the predicted load power and new energy output of each node, and simultaneously collect the corresponding actual load power and new energy output values; Calculate the load forecast error and renewable energy forecast error of each node at the current moment; based on the load forecast error and renewable energy forecast error, calculate the actual net load and net load forecast of the node at the current moment, and then obtain the net load fluctuation of the node. When the actual net load value is greater than the forecast value, it is determined that the node has an upward flexibility demand, and the corresponding net load fluctuation is quantified as the upward flexibility demand. When the actual net load value is less than the forecast value, it is determined that the node has a downward flexibility demand, and the absolute value of the corresponding net load fluctuation is quantified as the downward flexibility demand.

[0010] Furthermore, at any given moment, a flexibility requirement type determination and quantification operation is performed on any node to generate a unique flexibility requirement type and corresponding flexibility requirement quantity for that node at the current moment.

[0011] Furthermore, the specific steps in S2 for calculating the flexibility power flow distribution of each route include: Based on the node flexibility supply and node flexibility demand, calculate the net flexibility power of each node, whereby the net flexibility power is the net injection or absorption of flexibility power that a node can use to balance system fluctuations. Obtain the power grid topology and line reactance parameters from network data, and calculate the power transmission distribution factor matrix of the system based on the DC power flow model; The net flexibility power of each node in the step is converted into a vector form as the node power injection change and input into the power transmission distribution factor matrix. By multiplying the node net flexibility power vector with the power transmission distribution factor matrix, the flexibility power flow distribution on each line of the receiving-end power grid is obtained. The flexibility power flow distribution is the actual path and spatial distribution characteristics of flexibility resources transmitted from the supply node to the demand node.

[0012] Furthermore, in S3, the calculation of the flexibility transmission margin for each route specifically includes: The maximum transmission capacity data of each line in the network data is obtained by comparison; the value in the flexibility power flow distribution of each line is compared with the maximum transmission capacity of the corresponding line; the flexibility transmission margin of each line is calculated, which is the difference between the maximum transmission capacity of the line and the absolute value of the current flexibility power flow.

[0013] Furthermore, when the flexibility transmission margin of the route is negative, it is determined that the route is experiencing flexibility congestion.

[0014] According to a second aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the method described thereon.

[0015] According to a third aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described thereon.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) It realizes the leap from node assessment to network assessment in flexibility assessment, and improves the accuracy and practicality of assessment: Traditional methods are mainly limited to the flexibility supply and demand accounting at the node level, without fully considering the actual topology and transmission constraints of the power grid. By introducing power transmission distribution, the flexibility supply and demand of nodes is mapped to the flexibility power flow on the power grid lines, clearly depicting the spatial migration path and distribution characteristics of flexibility resources in the power grid. This makes the assessment results change from isolated node capacity accounting to a comprehensive analysis of the transmission capacity of the entire network, more accurately reflecting the actual dispatchable capacity of the system and improving the engineering implementation value of the assessment results.

[0017] (2) A complete interconnection model of sending and receiving ends was constructed, realizing the unified quantification and collaborative evaluation of cross-regional flexibility resources: By establishing a comprehensive flexibility supply model that takes into account the interconnection of sending and receiving ends, the regulation capacity of pumped storage distribution and AC / DC tie lines at the sending end is incorporated into the calculation of node flexibility supply, realizing the unified quantitative expression and collaborative regulation of cross-regional flexibility resources between the sending and receiving ends, so that the evaluation system can fully reflect the enhancement effect of cross-regional interconnection on the flexibility of the receiving end power grid, which is conducive to optimizing cross-regional power exchange strategies and exploring the collaboration between sending and receiving ends.

[0018] (3) The flexible transmission margin index and congestion criterion were proposed, which enabled accurate location and risk warning of power grid flexibility bottlenecks: Based on the calculation of flexible power flow, the flexible transmission margin was calculated by comparing the line flexible power flow with the maximum transmission capacity, and a clear congestion criterion was defined. The key channels and congestion locations that limit the system flexibility carrying capacity were quickly and automatically identified, and the quantitative assessment and accurate location of power grid flexibility congestion risk were realized. This provided direct and key decision information for the adjustment of power grid operation mode, channel expansion and optimization of flexible resources. Attached Figure Description

[0019] Figure 1 A flowchart of a power flow calculation method for receiving-end grid flexibility considering the interconnection between sending and receiving ends; Figure 2 A schematic diagram of data flow for power flow calculations to account for the flexibility of the receiving-end power grid interconnected with the sending and receiving ends; Figure 3 A schematic diagram of the flexibility resources of the sending and receiving power grids; Figure 4 This is a schematic diagram of power system flexibility flow. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 The diagram illustrates a method for calculating the flexibility power flow of a receiving-end power grid that takes into account the interconnection between the sending and receiving ends. The specific steps include: S1. Collect operational data of the receiving-end power grid, including resource data, forecast data, and network data; S2. Based on resource-related data, establish a local flexibility supply model that takes into account the flexibility support of the sending end and a comprehensive flexibility supply model that takes into account the interconnection between the sending and receiving ends, and calculate the nodal flexibility supply of the receiving end power grid; based on forecast data, construct a nodal flexibility demand model for the receiving end power grid, and combine the forecast errors of load and renewable energy output to obtain the nodal flexibility demand; based on network-related data, map the nodal flexibility supply and demand results to each line of the power grid through the power transmission distribution factor to obtain the flexibility power flow distribution that reflects the spatial migration path of flexibility resources. S3. Calculate the flexibility transmission margin for each line based on the flexible power flow distribution and the maximum transmission capacity of the line. S4. The calculation results of the combined node flexibility supply, node flexibility demand, flexibility power flow distribution and flexibility transmission margin are used to obtain the flexibility carrying capacity, which characterizes the overall flexibility of the receiving-end power grid.

[0022] like Figure 2The diagram illustrates the data flow for calculating the flexibility power flow of the receiving-end power grid in a sending-receiving-end interconnected system. Based on node-level flexibility supply and demand modeling, and combined with load and renewable energy output prediction errors, it constructs sets of upward / downward flexibility demand and supply for different time periods. The power transmission distribution factor (PTDF) maps node disturbances to line "flexibility power flow," quantifying the spatial migration paths of flexibility resources in the network and the contribution of sending-receiving-end interconnections. Furthermore, it establishes a flexibility transmission margin index and provides a method for identifying "flexibility congestion," forming a multi-level index system including system capacity, key channel flexibility utilization, node flexibility gap, and congestion sensitivity. This enables direct integration of assessment results with feasible scheduling, outputting decision-making information that can be used for channel expansion, resource location and capacity setting, and demand response incentive threshold setting. This embodiment overcomes the shortcomings of existing methods that only assess at the node net capacity level, neglect network constraints and interconnection paths, and struggle to locate bottlenecks. It significantly improves the accuracy, timeliness, and engineering operability of flexibility assessment; it exhibits good versatility across multiple scenarios and time scales, providing reliable decision support for improving the flexibility of the receiving-end power grid and cross-regional interconnection coordination. The flexibility resources provided by facilities such as pumped storage power plants in the sending-end power grid are connected to the receiving-end power grid via DC or AC tie lines. The flexibility of the receiving-end power grid mainly includes node flexibility and network transmission flexibility. A modeling analysis is performed based on the characteristics of the receiving-end power grid's flexibility resources. A schematic diagram of the sending-end and receiving-end power grid flexibility resources is shown below. Figure 3 As shown.

[0023] In S2, a receiving-end grid node flexibility model is established. Local flexibility resources such as receiving-end thermal power units, energy storage devices, and demand-side response are modeled according to their operational characteristics. The upward and downward flexibility supply capabilities of various resources are quantified, and a node-level flexibility supply index system is proposed. The specific steps for calculating node flexibility supply using the local flexibility supply model include: The input resource data includes local resource operation data, including thermal power unit operation data, energy storage equipment operation data, and demand-side response data. Thermal power unit operation data includes real-time output, technical output boundary, and ramp rate. Energy storage equipment operation data includes real-time charging and discharging power, state of charge, and power capacity of energy storage equipment. Demand-side response data includes interruptible load and real-time interruption level of demand-side response. Based on the operating data of thermal power units, the difference between the current output and the upper limit of output is calculated, and combined with the ramping capability constraint, to obtain the upward flexibility supply of the current thermal power unit within the dispatch interval; the difference between the current output and the lower limit of output is calculated, and combined with the ramping capability constraint, to obtain the downward flexibility supply of the current thermal power unit within the dispatch interval, expressed as: , in, and thermal power unitsa exist t Momentary up and down flexibility supply (MW); and These are the upper and lower limits (MW) of the output of thermal power unit a, respectively. For thermal power units a exist t The operating status at any given time, with a value of 0 indicating that the unit is out of service and a value of 1 indicating that the unit is in operation; For thermal power units a exist t Power output per second (MW); and thermal power units a Uphill and downhill climbing capacity (MW / h); This is the scheduling time interval.

[0024] Based on the operating data of the energy storage device, the difference between the maximum discharge power and the current discharge power is calculated, and the state of charge is checked to see if it is higher than the lower limit, thus obtaining the upward flexibility supply of the current energy storage device; the difference between the maximum charging power and the current charging power is calculated, and the state of charge is checked to see if it is lower than the upper limit, thus obtaining the downward flexibility supply of the current energy storage device, expressed as: , in, and Electrochemical energy storage a exist t Momentary up and down flexibility supply (MW); and Electrochemical energy storage Maximum charging and discharging power (MW); For electrochemical energy storage a exist t Power output per second (MW); For electrochemical energy storage Electricity (MW); and For electrochemical energy storage Upper and lower limits of energy consumption (MWh); and For electrochemical energy storage The charging and discharging efficiency.

[0025] Based on demand-side response data, the difference between the maximum interruptible load and the current interrupted load is calculated to obtain the upward flexibility supply of current demand-side response resources at the node. The expression is as follows: , in, Demand-side response node exist t Momentary upward flexibility supply (MW); At the node Maximum interruptible load (MW); For nodes In t Interruptible load output (MW) at any given time.

[0026] Based on the upward flexibility supply of thermal power units, the downward flexibility supply of thermal power units, the upward flexibility supply of energy storage equipment, the downward flexibility supply of energy storage equipment, and the upward flexibility supply of demand-side response resources, the local flexibility supply of the same node is obtained, which is the upward node flexibility supply and downward node flexibility supply of the current node without taking into account the sending-end flexibility support.

[0027] In S2, the specific steps for calculating node flexibility supply in the integrated flexibility supply model include: The cross-regional resource operation data in the input resource category includes the operation data of the sending-end pumped storage power station and the operation data of the sending-receiving end interconnection line; the operation data of the sending-end pumped storage power station includes the real-time output, power limit and reservoir capacity status of the sending-end pumped storage power station, and the operation data of the sending-receiving end interconnection line includes the real-time transmission power of the DC interconnection line between the sending and receiving ends, the real-time transmission power and power transmission limit of the AC interconnection line between the sending and receiving ends; Based on the operating data of the pumped storage power station at the sending end, the upward and downward flexibility supply considering reservoir capacity constraints is calculated. This is then combined with the pumped storage distribution coefficient of the corresponding node at the receiving end and the real-time power of the tie line to obtain the upward and downward flexibility supply transmitted to specific nodes at the receiving end through pumped storage distribution. The expressions are as follows: , in, and Pumped storage power station for sending-end power grid exist t Momentary up and down flexibility supply (MW); and Pumped storage power station Maximum power generation and maximum pumping power (MW); Pumped storage power station Power output (MW) at time t; and Pumped storage power station Upper and lower limits of reservoir capacity (m) 3 ); and Pumped storage power station Water conversion factor (m) during power generation / pumping3 / MWh); Pumped storage power station exist t Upper reservoir capacity at any given time (m³) 3 ).

[0028] Based on the operational data of the sender and receiver tie lines, the difference between the maximum and current transmission power of the tie line is calculated. Combined with the power up-rate constraint, the upward flexibility supply provided by the current tie line to the connected node at the receiver end is obtained. Similarly, by calculating the difference between the current and minimum transmission power, and combining this with the current power down-rate constraint, the downward flexibility supply provided by the tie line to the connected node at the receiver end is obtained, expressed as: , In the formula: and For nodes The connecting lines are in t The up and down flexibility (MW) provided at all times; For nodes Maximum transmission power (MW) of the connected tie line; With nodes The connecting lines are in t Transmitted power (MW) at any given time; and For nodes The rate of change of power (MW / h) on the connected tie line.

[0029] The node flexibility supply transmitted through pumped storage and distribution and the node flexibility supply provided by the sending and receiving end interconnection are superimposed to obtain the current node's upward node flexibility supply and downward node flexibility supply taking into account the sending and receiving end interconnection.

[0030] In S2, the specific steps for determining the flexibility requirements of computing nodes include: Input forecast data, including the predicted load power and new energy output of each node, and simultaneously collect the corresponding actual load power and new energy output values; Calculate the load forecast error and renewable energy forecast error of each node at the current moment; based on the load forecast error and renewable energy forecast error, calculate the actual net load and net load forecast of the node at the current moment, and then obtain the net load fluctuation of the node. When the actual net load value is greater than the forecast value, it is determined that the node has an upward flexibility demand, and the corresponding net load fluctuation is quantified as the upward flexibility demand. When the actual net load value is less than the forecast value, it is determined that the node has a downward flexibility demand, and the absolute value of the corresponding net load fluctuation is quantified as the downward flexibility demand.

[0031] At any given moment, perform a flexibility requirement type determination and quantification operation on any node to generate a unique flexibility requirement type and corresponding flexibility requirement quantity for that node at the current moment.

[0032] The flexibility requirement of receiving-end power grid nodes is represented by the changing trend of system net load, the forecasting error of new energy sources and loads, and the node flexibility requirement is directional, namely upward flexibility requirement. and downward flexibility requirements And at time t Time node Only upward or downward flexibility requirements can be generated, and the requirement formula is: , , , , , in, For nodes exist t Net load (MW) at any given time; For load exist t Actual power (MW) at any given time; For new energy exist t Actual output value (MW) at any given time; For load exist t Power prediction (MW) at time 10:00; For load exist t The prediction error value (MW) at time 1; For new energy exist t Power prediction (MW) at time 10:00; For new energy In t Time prediction error (MW).

[0033] In addition to the interconnection lines between the sending and receiving power grids, there are also network transmission channels, i.e., transmission lines, within the receiving power grid. Node flexibility supply and demand are transmitted within the receiving power grid through these network channels. Power system flexibility flow is defined as the potential flow that exists alongside power flow and characterizes the transmission of flexibility supply and demand within the system. Intuitively, power system flexibility flow is equivalent to adding a flexibility label to the flow on each branch, indicating the transmission status of flexibility supply and demand in the power system, such as... Figure 4 As shown.

[0034] At the node a Based on the power balance equation, when flexibility supply and demand arise, the power equation of the node considering flexibility is obtained. The power transmission distribution factor (PTDF) is used to reflect the power changes of the node onto the line, and the flexibility power flow is calculated. In this embodiment, the power transmission distribution factor (PTDF) refers to the power distribution factor of the node in the system. a The distribution coefficient of power change on power flow change of each transmission line is used to represent the proportion of power injected into each line in the power flow, and reflects the spatial distribution characteristics of power or flexibility in the network.

[0035] In the receiving-end power grid, not all flexibility resources of each node may be utilized. For each node, the available flexibility resources should not exceed the amount of flexibility resources that its individual devices can provide, corresponding to the following constraint: , in, Represents a node Various flexibility resources during operation exist t The supply of flexible resources (MW) that are actually available at any given time. This indicates the amount of flexibility resources that each device can provide for adjusting up or down. It represents a flexible supply of resources.

[0036] Receiving end grid node Power at time t for: , in, For nodes Load output (MW) at time t; For nodes The output of new energy sources (MW) at time t; For nodes The output of thermal power units (MW) at time t; For nodes The power output (MW) of the tie line at time t.

[0037] When flexibility demand arises, the power grid responds through energy management, utilizing flexibility resources to balance the resulting demand and restore equilibrium. Numerous transmission channels exist between receiving-end grid nodes and transmission lines, allowing node flexibility resources to be transmitted to the point of demand according to a predetermined allocation ratio, thus transferring flexibility supply and demand. During this transfer of flexibility supply and demand, the nodes... The power is: , In the formula: For access nodes The number of thermal power units; For access nodes The number of communication lines between the sending and receiving ends; For access nodes The number of demand-side responses; For access nodes The number of pumped storage substations; For access nodes The number of new energy storage devices.

[0038] Nodes are described using the power transfer distribution factor. Power changes affect the line The impact of power flow, based on the assumptions of the DC power flow model, represents any other arbitrary line. mn upper node y Side-injected power, node z The degree of change in power flow on the corresponding transmission line caused by the outflow of power is expressed as follows: , in, For nodes With the line k The power transfer distribution factor between them; This represents the power change between lines m and n. In order to be in The power change along the lower line yz is affected; For the reactance matrix, the first p line, number q Column elements.

[0039] line The flexibility power flow expression at time t for: , Where N represents the number of nodes in the receiving-end power grid.

[0040] The specific steps for calculating the flexibility power flow distribution of each route include: Based on the supply and demand of node flexibility, the net flexibility power of each node is calculated. The net flexibility power is the net injection or absorption of flexibility power that a node can use to balance system fluctuations. Obtain the power grid topology and line reactance parameters from network data, and calculate the power transmission distribution factor matrix of the system based on the DC power flow model; The net flexibility power of each node in the step is converted into a vector form as the node power injection change and input into the power transmission distribution factor matrix. By multiplying the node net flexibility power vector with the power transmission distribution factor matrix, the flexibility power flow distribution on each line of the receiving-end power grid is obtained. The flexibility power flow distribution is the actual path and spatial distribution characteristics of flexibility resources from the supply node to the demand node.

[0041] In S3, the calculation of the flexibility transport margin for each route specifically includes: The maximum transmission capacity data of each line in the network data is obtained by comparison; the value in the flexibility power flow distribution of each line is compared with the maximum transmission capacity of the corresponding line; the flexibility transmission margin of each line is calculated, which is the difference between the maximum transmission capacity of the line and the absolute value of the current flexibility power flow.

[0042] When the flexibility margin of a route is negative, it is determined that the route is experiencing flexibility congestion.

[0043] The transmission flexibility of the receiving-end power grid is limited by the upper limit of line transmission capacity. The flexible transmission capacity of a line is related to its current flexible power flow and its maximum transmission capacity. When the flexible power flow of a line becomes overloaded, a flexibility blockage is defined. Establish a receiving-end power grid transmission flexibility margin index: , In the formula: To ensure the flexibility and carrying capacity of the receiving-end power grid network; This represents the maximum transmission capacity of the line; when When ≥0, the line k Ample flexibility, when When <0, the line k This creates a blockage in flexibility.

[0044] This embodiment addresses the problems of distorted assessments and difficulty in bottleneck location caused by neglecting network transmission capacity and sender-receiver interconnection in receiving-end power grid flexibility evaluation. It proposes a receiving-end power grid flexibility evaluation method that considers sender-receiver interconnection based on flexibility power flow. First, it simultaneously characterizes node flexibility supply and demand within a unified framework and maps them to flexibility power flow via the power transmission distribution factor (PTDF), considering both physical networks and inter-regional interconnection paths to avoid biases caused by measuring flexibility solely based on node net capacity. Second, it establishes a flexibility transmission margin index and defines flexibility congestion, enabling rapid identification of key channels and bottleneck locations limiting system flexibility capacity, and quantitatively providing the degree of congestion and its constraint on the scale of dispatchable flexibility. This method quantifies the effect of sender-receiver interconnection on the receiving-end flexibility capacity, providing a basis for optimizing tie-line operation strategies and expanding channel capacity. It maintains good versatility and scalability across multiple scenarios and time scales, and can be linked with intraday planning, real-time scheduling, and medium- to long-term planning to guide the location and capacity determination of flexibility resources and the setting of demand response incentive thresholds. Overall, this embodiment effectively improves the accuracy and timeliness of receiving-end grid flexibility assessment, shortens the bottleneck location and strategy verification cycle, reduces the risk of wind and solar power curtailment and load gaps caused by insufficient understanding of network constraints, and provides reliable decision support for improving the flexibility of complex power grids and cross-regional collaboration.

[0045] Example 2 Based on the method of Embodiment 1, this embodiment provides a flexible power flow calculation system for a receiving-end interconnected power grid, including: a data acquisition unit, a flexible supply and demand calculation unit, a flexible power flow analysis unit, a transmission margin and congestion determination unit, and a comprehensive evaluation unit. The data acquisition unit is used to collect operational data of the receiving-end power grid, including resource data, forecast data, and network data.

[0046] The flexibility supply and demand calculation unit is connected to the data acquisition unit. It is used to establish and calculate the local flexibility supply model that does not take into account the flexibility support of the sending end and the comprehensive flexibility supply model that takes into account the interconnection between the sending and receiving ends based on resource data, so as to obtain the node flexibility supply of each node in the receiving end power grid; based on forecast data, it constructs and calculates the node flexibility demand model of the receiving end power grid, and combines the forecast errors of load and new energy output to obtain the node flexibility demand of each node.

[0047] The flexibility power flow analysis unit is connected to the flexibility supply and demand calculation unit and the data acquisition unit. It is used to map the node flexibility supply and node flexibility demand to each line of the power grid through the power transmission distribution factor based on the network data, and calculate the flexibility power flow distribution that reflects the spatial migration path of flexibility resources.

[0048] The transmission margin and congestion determination unit is connected to the flexibility power flow analysis unit and is used to calculate the flexibility transmission margin of each line based on the flexibility power flow distribution and the maximum transmission capacity of the line, and determine the flexible congestion line based on the margin.

[0049] The comprehensive evaluation unit is connected to the flexibility supply and demand calculation unit, the flexibility power flow analysis unit, and the transmission margin and congestion determination unit. It is used to calculate the flexibility supply, flexibility demand, flexibility power flow distribution, and flexibility transmission margin of the nodes to obtain the flexibility carrying capacity, which characterizes the overall flexibility of the receiving-end power grid.

[0050] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the described module can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0051] The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0052] Multiple components in the device are connected to an I / O interface, including: input units such as a keyboard, mouse, etc.; output units such as various types of displays, speakers, etc.; storage units such as disks, optical disks, etc.; and communication units such as network interface cards, modems, wireless transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks. The processing unit performs the various methods and processes described above, such as the method of the present invention. For example, in some embodiments, the method of the present invention may be implemented as a computer software program tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or the communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the method of the present invention described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute the method of the present invention by any other suitable means (e.g., by means of firmware).

[0053] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0054] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0055] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for flexible power flow calculation of a receiving end power grid considering the interconnection of a sending end and a receiving end, characterized in that, The specific steps include: S1, collecting operation data of the receiving-end power grid, including resource type data, prediction type data and network type data; S2, based on the resource type data, establishing a local flexibility supply model considering the sending-end flexibility support and a comprehensive flexibility supply model considering the sending-receiving-end interconnection, calculating the node flexibility supply amount of the receiving-end power grid; based on the prediction type data, constructing a node flexibility demand model of the receiving-end power grid, combining the prediction error of load and new energy output, obtaining the node flexibility demand amount; based on the network type data, mapping the node flexibility supply and demand results to each line of the power grid through the power transmission distribution factor, obtaining the flexibility flow distribution reflecting the spatial migration path of the flexibility resource; S3, according to the flexibility flow distribution and the maximum transmission capacity of the line, calculating the flexibility transmission margin of each line; S4, comprehensively calculating the flexibility carrying degree representing the overall flexibility of the receiving-end power grid based on the calculation results of the node flexibility supply amount, the node flexibility demand amount, the flexibility flow distribution and the flexibility transmission margin. 2.The method of claim 1, wherein, In the S2, the specific steps of the local flexibility supply model for calculating the node flexibility supply include: inputting the local resource operation data in the resource type data, including the thermal power unit operation data, the energy storage device operation data and the demand side response data; the thermal power unit operation data includes the real-time output, the technical output boundary and the climbing rate, the energy storage device operation data includes the real-time charge and discharge power, the state of charge and the power capacity of the energy storage device, and the demand side response data includes the interruptible load amount and the real-time interruption level of the demand side response; based on the thermal power unit operation data, calculating the difference between the current output and the upper limit of the output and combining the climbing capacity constraint to obtain the upward flexibility supply amount of the current thermal power unit in the dispatching interval; calculating the difference between the current output and the lower limit of the output and combining the climbing capacity constraint to obtain the downward flexibility supply amount of the current thermal power unit in the dispatching interval; based on the energy storage device operation data, calculating the difference between the maximum discharge power and the current discharge power, and verifying whether the state of charge is higher than the lower limit to obtain the upward flexibility supply amount of the current energy storage device; calculating the difference between the maximum charge power and the current charge power, and verifying whether the state of charge is lower than the upper limit to obtain the downward flexibility supply amount of the current energy storage device; based on the demand side response data, calculating the difference between the maximum interruptible load amount and the current interrupted load amount to obtain the upward flexibility supply amount of the current demand side response resource at the node; according to the upward flexibility supply amount of the thermal power unit, the downward flexibility supply amount of the thermal power unit, the upward flexibility supply amount of the energy storage device, the downward flexibility supply amount of the energy storage device and the upward flexibility supply amount of the demand side response resource, obtaining the local flexibility supply amount of the same node, i.e. the upward node flexibility supply amount and the downward node flexibility supply amount of the current node not considering the sending-end flexibility support. 3.The method of claim 1, wherein, In the S2, the specific steps of the comprehensive flexibility supply model for calculating the node flexibility supply include: The cross-region resource operation data in the input resource class data includes the sending-end pumped storage power station operation data and the sending-receiving-end tie-line operation data; the sending-end pumped storage power station operation data includes real-time output, power limit and reservoir capacity state of the sending-end pumped storage power station, and the sending-receiving-end tie-line operation data includes real-time transmission power of the direct-current tie-line between the sending and receiving ends, real-time transmission power and power transmission limit of the alternating-current tie-line between the sending and receiving ends; Based on the sending-end pumped storage power station operation data, the upward and downward flexibility supply amounts considering the reservoir capacity constraint are calculated, and combined with the pumped storage power distribution coefficient of the corresponding node of the receiving end and the real-time power of the tie-line, the upward and downward flexibility supply amounts transferred to the specific node of the receiving end in the form of pumped storage power distribution are obtained; Based on the sending-receiving-end tie-line operation data, the difference between the maximum transmission power and the current transmission power of the tie-line is calculated, and combined with the power up-regulation rate constraint, the upward flexibility supply amount provided by the tie-line for the connected node of the receiving end is obtained; by calculating the difference between the current transmission power and the minimum transmission power, combined with the current power down-regulation rate constraint, the downward flexibility supply amount provided by the tie-line for the connected node of the receiving end is obtained; The node flexibility supply amount transferred in the form of pumped storage power distribution and the node flexibility supply amount provided by the sending-receiving-end tie-line are superimposed to obtain the upward node flexibility supply amount and the downward node flexibility supply amount of the current node considering the sending-receiving-end interconnection. 4.The method of claim 1, wherein, In S2, the specific steps of calculating the node flexibility demand amount include: Input the prediction class data, including the load power prediction value and the new energy output prediction value of each node, and synchronously collect the actual values of the corresponding load power and new energy output; Calculate the load prediction error value and the new energy prediction error value of each node at the current time; according to the load prediction error value and the new energy prediction error value, calculate the actual value and the predicted value of the net load of the node at the current time, and then obtain the net load fluctuation amount of the node; When the actual value of the net load is greater than the predicted value, it is determined that the node generates upward flexibility demand, and the corresponding net load fluctuation amount is quantified as the upward flexibility demand amount; when the actual value of the net load is less than the predicted value, it is determined that the node generates downward flexibility demand, and the absolute value of the corresponding net load fluctuation amount is quantified as the downward flexibility demand amount.

5. The method of claim 4, wherein, At any time, the flexibility demand type judgment and quantification operation is performed once for any node to generate the unique flexibility demand type and the corresponding flexibility demand amount of the node at the current time.

6. The method of claim 1, wherein, The specific steps of calculating the flexibility flow distribution of each route in S2 include: Based on the node flexibility supply amount and the node flexibility demand amount, the net flexibility power of each node is calculated, which is the net injection or absorption flexibility power that can be used by the node to balance the system fluctuation; The power transmission distribution factor matrix of the system is calculated based on the direct-current flow model, by acquiring the power grid topology and line reactance parameters in the network class data; The net flexibility power of each node in the step is taken as a node power injection change amount, converted into a vector form, and input into the power transmission distribution factor matrix; by multiplying the node net flexibility power vector with the power transmission distribution factor matrix, flexibility flow distribution on each line of the receiving end power grid is obtained, and the flexibility flow distribution is an actual path and spatial distribution characteristic of the flexibility resource transmitted from the supply node to the demand node.

7. The method of claim 1, wherein, The calculation of the flexibility transmission margin of each route in the S3 specifically includes: The maximum transmission capacity data of each line in the network type data is compared; the value in the flexibility flow distribution of each line is compared with the maximum transmission capacity of the corresponding line; and the flexibility transmission margin of each line is calculated, and the flexibility transmission margin is the difference between the maximum transmission capacity of the line and the absolute value of the current flexibility flow. 8.The method of claim 7, wherein, When the flexibility transmission margin of the route is a negative value, it is determined that the flexibility congestion occurs in the line.

9. An electronic device comprising a memory and a processor, said memory having stored thereon a computer program, characterized in that, The processor executes the program to implement the method in any one of claims 1-8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the method in any one of claims 1-8.

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