A power system flexibility evaluation method and system considering resource transmission characteristics

Abstract

This invention belongs to the field of power system operation technology, specifically relating to a power system flexibility assessment method and system that takes into account resource transmission characteristics. The method first establishes a system operation model with the optimization objective of minimizing the total system cost. Then, based on load and renewable energy output forecast data, the system operation model is solved to obtain the system operating state. Based on the system operating state, the flexibility resource deficit is calculated, and the system flexibility assessment is achieved based on the flexibility resource deficit. The above design, when constructing the system operation model, sets transmission constraints on the supply and demand balance of flexibility resources by the system transmission channels, fully considering the transmission capacity limitations of the system transmission channels, thereby improving the accuracy of the flexibility assessment results.

Description

Technical Field

[0001] This invention belongs to the field of power system operation technology, and specifically relates to a method, system, equipment and medium for power system flexibility assessment that takes into account resource transmission characteristics. Background Technology

[0002] As the energy system gradually shifts towards a cleaner, lower-carbon, safer, and more efficient direction, the planning for grid connection of new energy sources is constantly expanding. The randomness, intermittency, and volatility of new energy power generation pose significant challenges to the planning and operation of the power system. Wind and solar power curtailment is a frequent occurrence, fundamentally due to the insufficient flexibility of the power system. A comprehensive assessment of the power system's flexibility is crucial for providing a basis for power system planning and operation, and is of great significance for reducing wind and solar power curtailment and load shedding losses, as well as promoting the clean energy transition.

[0003] Current flexibility assessment studies typically only consider whether a power system has sufficient flexibility adjustment resources, rarely taking into account line congestion caused by insufficient transmission capacity in actual operation. Line congestion restricts the cross-regional transmission of renewable energy, forcing a large amount of adjustable flexibility resources in regions with abundant resources to be wasted due to the inability to transmit them, especially in areas with high renewable energy penetration, where wind and solar power curtailment is more pronounced. In regions with scarce flexibility resources, the inability to obtain external power support leads to a decrease in system frequency and voltage stability, and in extreme cases, can easily trigger load shedding. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by providing a power system flexibility assessment method, system, device, and medium that takes into account the transmission capacity limitations of the system transmission channels and improves the accuracy of flexibility assessment results by taking into account resource transmission characteristics.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for assessing the flexibility of a power system that takes into account resource transmission characteristics, the method comprising:

[0007] S1. Establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints of the system transmission channel on the supply and demand balance of flexible resources.

[0008] S2. Solve the system operation model based on load and new energy output forecast data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize the system flexibility assessment based on the flexibility resource deficit.

[0009] The transmission constraints of the system transmission channel on the supply and demand balance of flexible resources include the transmission constraints of the system transmission channel at the upper and lower boundaries of the net load on the supply and demand balance of flexible resources; the transmission constraints of the system transmission channel at the upper boundary of the net load on the supply and demand balance of flexible resources include: considering system nodes at the upper boundary of the net load. Nodes that actually utilize flexible resources Virtual net power constraints, net load upper boundary except for nodes Virtual net power constraints and net load upper boundaries at other nodes of the external system are passed through system nodes. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The flexibility of resource requirements is constrained.

[0010] The total system cost includes the system's thermal power generation cost, renewable energy curtailment penalty cost, load shedding penalty cost, and virtual flexibility deficiency penalty cost at the net load boundary; the objective function expression of the system operation model is as follows:

[0011] ;

[0012] ;

[0013] ;

[0014] ;

[0015] ;

[0016] In the above formula, The total cost of the power system; , , These are the power generation costs of thermal power units, the penalty costs for abandoning new energy sources, and the penalty costs for load shedding; , These are the penalty costs for insufficient virtual flexibility at the upper and lower boundaries of the system net load, respectively. , They are respectively Time Node Insufficient virtual flexibility at the upper and lower boundaries of net load incurs penalty costs. , They are respectively Time Node The balance between supply and demand of flexibility resources at the upper and lower boundaries of net load; , , All are thermal power units The power generation cost coefficient; for Typical scenarios Lower thermal power unit ; output power; , These are the cost coefficients for abandoning new energy sources and the cost coefficients for load shedding, respectively. , They are respectively Time Node The maximum output power and actual absorption power of new energy sources; , They are respectively Time Node The required power supply and the actual power supply; , , These are respectively thermal power units, new energy sources, and system node sets; , The penalties for insufficient flexibility in adjusting upward and downward adjustments are respectively: The scheduling period; This represents the number of system nodes.

[0017] System node at the upper boundary of the net load The virtual net power constraints include:

[0018] ;

[0019] In the above formula, At the upper boundary Time Node Virtual net power, superscript This indicates the introduction of virtual quantities, making it easier to distinguish them from actual system quantities; for Time Node The upper boundary of net load; , , , They are respectively Time Node The output of thermal power units, the output of hydropower units, the power generation of pumped storage units, and the pumping power of pumped storage units; , , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units, hydropower units, and pumped storage units used;

[0020] The system at the upper boundary of the net load, excluding nodes The virtual net power constraints for other nodes include:

[0021] ;

[0022] ;

[0023] ;

[0024] ;

[0025] In the above formula, , At the upper boundary Time Branch Branch roads Virtual active power flow; , Representing the nodes respectively A set of connected first and last nodes; , At the upper boundary Time Node ,node The virtual node voltage phase angle; branch road The per-unit value of reactance; , They are nodes The upper and lower limits of the voltage phase angle; branch road The capacity of the transmission lines;

[0026] The upper boundary of the net load is reached through the system node. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The constraints on flexibility and resource requirements include:

[0027] ;

[0028] ;

[0029] In the above formula, Node at the upper bound The total amount of flexible supply; For nodes transmitted via lines Total amount of flexible resources; For the upper boundary Time Node The actual trend.

[0030] The formula for calculating the shortage of flexibility resources is as follows:

[0031] ;

[0032] ;

[0033] ;

[0034] ;

[0035] In the above formula, , They are respectively Time Node The upward and downward adjustment of flexibility resources shortage; , They are respectively Time Node The balance between supply and demand of flexible resources at the upper and lower boundaries; , These are the nodes at the upper and lower boundaries, respectively. The actual total amount of flexible resource supply used; , respectively Time Node The need for flexibility resources at the upper and lower boundaries.

[0036] The system operation constraints include power flow balance constraints, line capacity constraints, thermal power unit output constraints, hydropower unit output constraints, pumped storage unit operation constraints, node voltage phase angle constraints, and actual utilization constraints of flexibility resources.

[0037] The power flow balance constraints include:

[0038] ;

[0039] In the above formula, , , , These are the output vectors of thermal power units, hydropower units, new energy units, and nodal load vectors, respectively. , These are the pumped-storage unit power vector and the pumping power vector, respectively. , These are the node admittance matrix and the node voltage phase angle vector, respectively.

[0040] The line capacity constraints include:

[0041] ;

[0042] In the above formula, , They are respectively Timetable The actual active power flow and transmission limit;

[0043] The power output constraints of the thermal power unit include:

[0044] ;

[0045] In the above formula, , They are respectively time, Time Node The output of thermal power units; They are respectively thermal power units ; output power; , thermal power units The upper and lower limits of output; , thermal power units The rate of upward and downward climbing; The scheduling time interval;

[0046] The hydropower output constraints include hydropower station constraints and hydropower unit constraints. The hydropower station constraints include hydraulic connection constraints, water level constraints, outflow constraints, hydropower station output constraints, water level-reservoir capacity relationship constraints, and tailrace level-discharge relationship constraints. The hydraulic connection constraints include:

[0047] ;

[0048] ;

[0049] ;

[0050] In the above formula, , For hydroelectric power station exist time, Storage capacity at any given time; For hydroelectric power station exist Inbound traffic at any given time; For hydroelectric power station exist Real-time outbound flow; For hydroelectric power station With its upstream hydropower station Water flow stagnation time; To take into account the water flow lag time of the hydropower station During the period Outbound flow; For hydroelectric power station With its upstream hydropower station Between Interval flow at any given time; , Hydropower stations Pumped storage unit's pumping and power generation flow rates; , Hydropower stations exist Real-time power generation and water discharge flow;

[0051] The water level constraints include:

[0052] ;

[0053] ;

[0054] In the above formula, For hydroelectric power station In the reservoir The water level in front of the dam at any given time. , Hydropower stations The upper and lower limits of the water level in front of the dam of the reservoir; For hydroelectric power station Initial water level during the scheduling period;

[0055] The outbound flow constraints include:

[0056] ;

[0057] In the above formula, For hydroelectric power station exist Real-time outbound flow; , Hydropower stations The upper and lower limits of outbound flow;

[0058] The power output constraints of the hydropower station include:

[0059] ;

[0060] In the above formula, For hydroelectric power station exist Total output at any given moment; , Hydropower stations The upper and lower limits of output;

[0061] The constraints on the relationship between water level and reservoir capacity include:

[0062] ;

[0063] In the above formula, For hydroelectric power station exist Storage capacity at any given time; For hydroelectric power station The nonlinear relationship curve function between water level and reservoir capacity of the reservoir is shown in the figure.

[0064] The constraints on the relationship between tailwater level and discharge volume include:

[0065] ;

[0066] In the above formula, For hydroelectric power station exist The tailwater level at that moment; For hydroelectric power station The nonlinear relationship curve function between tailwater level and discharge capacity;

[0067] The water level constraints include unit output constraints, unit power generation flow constraints, unit output ramp-up constraints, unit power generation head constraints, and unit dynamic characteristic constraints; the unit output constraints include:

[0068] ;

[0069] ;

[0070] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Efforts made at all times; , Hydropower stations The The upper and lower limits of the output of the hydroelectric generator unit; For hydroelectric power station The total number of hydropower units included; For hydroelectric power station contribution;

[0071] The unit's power generation flow constraints include:

[0072] ;

[0073] ;

[0074] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Power generation flow rate at any given moment; , Hydropower stations The The upper and lower limits of the power generation flow of the hydroelectric generating unit in Taiwan;

[0075] The unit output ramp-up constraints include:

[0076] ;

[0077] In the above formula, , Hydropower stations The Taiwan hydroelectric power unit time, Efforts made at all times; For hydroelectric power station The The hill-climbing ability of the hydroelectric generator unit;

[0078] The generator head constraint includes:

[0079] ;

[0080] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit The constant head of the generator; , Hydropower stations The reservoir is located in time, The water level in front of the dam at any given time;

[0081] The unit dynamic characteristic constraints include:

[0082] ;

[0083] In the above formula, For hydroelectric power station The The nonlinear relationship between the output of the hydroelectric generator unit and the power generation flow rate and power generation head;

[0084] The operating constraints of the pumped storage unit include:

[0085] ;

[0086] ;

[0087] ;

[0088] ;

[0089] ;

[0090] ;

[0091] ;

[0092] In the above formula, , Hydropower stations The pumping and power generation flow of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The real-time status of pumping and power generation; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation capacity at any given time; , , , Hydropower stations The Minimum pumping power, maximum pumping power, minimum generating power, and maximum generating power of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation flow rates at any given time; , These are the pumping and power generation efficiencies of a single pumped-storage unit, respectively. , These are the average density of water and the acceleration due to gravity, respectively. For hydroelectric power station The average head; For hydroelectric power station The number of pumped storage units;

[0093] The node voltage phase angle constraint includes:

[0094] ;

[0095] In the above formula, For nodes exist Voltage phase angle at any given moment; , These represent the maximum and minimum values ​​of the node voltage phase angle, respectively. For the system node set;

[0096] The actual usage constraints of the flexibility resources include the actual usage constraints of thermal power units, hydropower units, and pumped storage units. The actual usage constraints of thermal power units include:

[0097] ;

[0098] ;

[0099] ;

[0100] ;

[0101] In the above formula, In response The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units dispatched; , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of power units that can be deployed is provided to ensure flexibility in adjusting power supply and demand. , It is a 0-1 variable used to limit the thermal power unit to only be able to call up or down the flexibility adjustment capability at the same time, and the actual amount called up cannot exceed the available supply. , They are nodes The flexibility of adjusting the power supply to the upper and lower limits of thermal power units can be improved.

[0102] The system flexibility assessment based on flexibility resource shortage includes: determining whether the sum of the system flexibility resource shortages of all nodes is zero. If so, it indicates that there is no flexibility resource shortage problem in the system, and the system flexibility resources and system transmission channels are sufficient. Otherwise, it indicates that there is a flexibility resource shortage problem in the system. Then, it further compares the sum of the total flexibility supply of all nodes with the sum of the flexibility demand of all nodes. If the sum of the total flexibility supply of all nodes is greater than the sum of the flexibility demand of all nodes, it indicates that the system flexibility resources are sufficient but the transmission channels are insufficient. If the sum of the total flexibility supply of all nodes is less than the sum of the flexibility demand of all nodes, it further determines whether there is an absolute value of the line virtual active power flow load rate equal to 1. If so, it indicates that both the system flexibility resources and system transmission channels are insufficient. Otherwise, it indicates that the system flexibility resources are insufficient but the transmission channels are sufficient.

[0103] Secondly, the present invention provides a power system flexibility assessment system that takes into account resource transmission characteristics. The power system flexibility assessment system is based on the aforementioned power system flexibility assessment method and includes a model building module and a flexibility assessment module.

[0104] The model building module is used to establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints of the system transmission channel on the supply and demand balance of flexible resources.

[0105] The flexibility assessment module is used to solve the system operation model based on load and new energy output forecast data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize the system flexibility assessment based on the flexibility resource deficit.

[0106] The transmission constraints of the system transmission channel on the supply and demand balance of flexible resources include the transmission constraints of the system transmission channel at the upper and lower boundaries of the net load on the supply and demand balance of flexible resources; the transmission constraints of the system transmission channel at the upper boundary of the net load on the supply and demand balance of flexible resources include: considering system nodes at the upper boundary of the net load. Nodes that actually utilize flexible resources Virtual net power constraints, net load upper boundary except for nodes Virtual net power constraints and net load upper boundaries at other nodes of the external system are passed through system nodes. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The flexibility of resource requirements is constrained.

[0107] The total system cost includes the system's thermal power generation cost, renewable energy curtailment penalty cost, load shedding penalty cost, and virtual flexibility deficiency penalty cost at the net load boundary; the objective function expression of the system operation model is as follows:

[0108] ;

[0109] ;

[0110] ;

[0111] ;

[0112] ;

[0113] In the above formula, The total cost of the power system; , , These are the power generation costs of thermal power units, the penalty costs for abandoning new energy sources, and the penalty costs for load shedding; , These are the penalty costs for insufficient virtual flexibility at the upper and lower boundaries of the system net load, respectively. , They are respectively Time Node Insufficient virtual flexibility at the upper and lower boundaries of net load incurs penalty costs. , They are respectively Time Node The balance between supply and demand of flexibility resources at the upper and lower boundaries of net load; , , All are thermal power units The power generation cost coefficient; for Typical scenarios Lower thermal power unit ; output power; , These are the cost coefficients for abandoning new energy sources and the cost coefficients for load shedding, respectively. , They are respectively Time Node The maximum output power and actual absorption power of new energy sources; , They are respectively Time Node The required power supply and the actual power supply; , , These are respectively thermal power units, new energy sources, and system node sets; , The penalties for insufficient flexibility in adjusting upward and downward adjustments are respectively: The scheduling period; This represents the number of system nodes.

[0114] System node at the upper boundary of the net load The virtual net power constraints include:

[0115] ;

[0116] In the above formula, At the upper boundary Time Node Virtual net power, superscript This indicates the introduction of virtual quantities, making it easier to distinguish them from actual system quantities; for Time Node The upper boundary of net load; , , , They are respectively Time Node The output of thermal power units, the output of hydropower units, the power generation of pumped storage units, and the pumping power of pumped storage units; , , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units, hydropower units, and pumped storage units used;

[0117] The system at the upper boundary of the net load, excluding nodes The virtual net power constraints for other nodes include:

[0118] ;

[0119] ;

[0120] ;

[0121] ;

[0122] In the above formula, , At the upper boundary Time Branch Branch roads Virtual active power flow; , Representing the nodes respectively A set of connected first and last nodes; , At the upper boundary Time Node ,node The virtual node voltage phase angle; branch road The per-unit value of reactance; , They are nodes The upper and lower limits of the voltage phase angle; branch road The capacity of the transmission lines;

[0123] The upper boundary of the net load is reached through the system node. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The constraints on flexibility and resource requirements include:

[0124] ;

[0125] ;

[0126] In the above formula, Node at the upper bound The total amount of flexible supply; For nodes transmitted via lines Total amount of flexible resources; For the upper boundary Time Node The actual trend.

[0127] The formula for calculating the shortage of flexibility resources is as follows:

[0128] ;

[0129] ;

[0130] ;

[0131] ;

[0132] In the above formula, , They are respectively Time Node The upward and downward adjustment of flexibility resources shortage; , They are respectively Time Node The balance between supply and demand of flexible resources at the upper and lower boundaries; , These are the nodes at the upper and lower boundaries, respectively. The actual total amount of flexible resource supply used; , respectively Time Node The need for flexibility resources at the upper and lower boundaries.

[0133] The system operation constraints include power flow balance constraints, line capacity constraints, thermal power unit output constraints, hydropower unit output constraints, pumped storage unit operation constraints, node voltage phase angle constraints, and actual utilization constraints of flexibility resources.

[0134] The power flow balance constraints include:

[0135] ;

[0136] In the above formula, , , , These are the output vectors of thermal power units, hydropower units, new energy units, and nodal load vectors, respectively. , These are the pumped-storage unit power vector and the pumping power vector, respectively. , These are the node admittance matrix and the node voltage phase angle vector, respectively.

[0137] The line capacity constraints include:

[0138] ;

[0139] In the above formula, , They are respectively Timetable The actual active power flow and transmission limit;

[0140] The power output constraints of the thermal power unit include:

[0141] ;

[0142] In the above formula, , They are respectively time, Time Node The output of thermal power units; They are respectively thermal power units ; output power; , thermal power units The upper and lower limits of output; , thermal power units The rate of upward and downward climbing; The scheduling time interval;

[0143] The hydropower output constraints include hydropower station constraints and hydropower unit constraints. The hydropower station constraints include hydraulic connection constraints, water level constraints, outflow constraints, hydropower station output constraints, water level-reservoir capacity relationship constraints, and tailrace level-discharge relationship constraints. The hydraulic connection constraints include:

[0144] ;

[0145] ;

[0146] ;

[0147] In the above formula, , For hydroelectric power station exist time, Storage capacity at any given time; For hydroelectric power station exist Inbound traffic at any given time; For hydroelectric power station exist Real-time outbound flow; For hydroelectric power station With its upstream hydropower station Water flow stagnation time; To take into account the water flow lag time of the hydropower station During the period Outbound flow; For hydroelectric power station With its upstream hydropower station Between Interval flow at any given time; , Hydropower stations Pumped storage unit's pumping and power generation flow rates; , Hydropower stations exist Real-time power generation and water discharge flow;

[0148] The water level constraints include:

[0149] ;

[0150] ;

[0151] In the above formula, For hydroelectric power station In the reservoir The water level in front of the dam at any given time. , Hydropower stations The upper and lower limits of the water level in front of the dam of the reservoir; For hydroelectric power station Initial water level during the scheduling period;

[0152] The outbound flow constraints include:

[0153] ;

[0154] In the above formula, For hydroelectric power station exist Real-time outbound flow; , Hydropower stations The upper and lower limits of outbound flow;

[0155] The power output constraints of the hydropower station include:

[0156] ;

[0157] In the above formula, For hydroelectric power station exist Total output at any given moment; , Hydropower stations The upper and lower limits of output;

[0158] The constraints on the relationship between water level and reservoir capacity include:

[0159] ;

[0160] In the above formula, For hydroelectric power station exist Storage capacity at any given time; For hydroelectric power station The nonlinear relationship curve function between water level and reservoir capacity of the reservoir is shown in the figure.

[0161] The constraints on the relationship between tailwater level and discharge volume include:

[0162] ;

[0163] In the above formula, For hydroelectric power station exist The tailwater level at that moment; For hydroelectric power station The nonlinear relationship curve function between tailwater level and discharge capacity;

[0164] The water level constraints include unit output constraints, unit power generation flow constraints, unit output ramp-up constraints, unit power generation head constraints, and unit dynamic characteristic constraints; the unit output constraints include:

[0165] ;

[0166] ;

[0167] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Efforts made at all times; , Hydropower stations The The upper and lower limits of the output of the hydroelectric generator unit; For hydroelectric power station The total number of hydropower units included; For hydroelectric power station contribution;

[0168] The unit's power generation flow constraints include:

[0169] ;

[0170] ;

[0171] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Power generation flow rate at any given moment; , Hydropower stations The The upper and lower limits of the power generation flow of the hydroelectric generating unit in Taiwan;

[0172] The unit output ramp-up constraints include:

[0173] ;

[0174] In the above formula, , Hydropower stations The Taiwan hydroelectric power unit time, Efforts made at all times; For hydroelectric power station The The hill-climbing ability of the hydroelectric generator unit;

[0175] The generator head constraint includes:

[0176] ;

[0177] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit The constant head of the generator; , Hydropower stations The reservoir is located in time, The water level in front of the dam at any given time;

[0178] The unit dynamic characteristic constraints include:

[0179] ;

[0180] In the above formula, For hydroelectric power station The The nonlinear relationship between the output of the hydroelectric generator unit and the power generation flow rate and power generation head;

[0181] The operating constraints of the pumped storage unit include:

[0182] ;

[0183] ;

[0184] ;

[0185] ;

[0186] ;

[0187] ;

[0188] ;

[0189] In the above formula, , Hydropower stations The pumping and power generation flow of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The real-time status of pumping and power generation; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation capacity at any given time; , , , Hydropower stations The Minimum pumping power, maximum pumping power, minimum generating power, and maximum generating power of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation flow rates at any given time; , These are the pumping and power generation efficiencies of a single pumped-storage unit, respectively. , These are the average density of water and the acceleration due to gravity, respectively. For hydroelectric power station The average head; For hydroelectric power station The number of pumped storage units;

[0190] The node voltage phase angle constraint includes:

[0191] ;

[0192] In the above formula, For nodes exist Voltage phase angle at any given moment; , These represent the maximum and minimum values ​​of the node voltage phase angle, respectively. For the system node set;

[0193] The actual usage constraints of the flexibility resources include the actual usage constraints of thermal power units, hydropower units, and pumped storage units. The actual usage constraints of thermal power units include:

[0194] ;

[0195] ;

[0196] ;

[0197] ;

[0198] In the above formula, In response The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units dispatched; , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of power units that can be deployed is provided to ensure flexibility in adjusting power supply and demand. , It is a 0-1 variable used to limit the thermal power unit to only be able to call up or down the flexibility adjustment capability at the same time, and the actual amount called up cannot exceed the available supply. , They are nodes The flexibility of adjusting the power supply to the upper and lower limits of thermal power units can be improved.

[0199] The flexibility assessment module is used to assess system flexibility according to the following steps: First, it determines whether the sum of the system flexibility resource deficits of all nodes is zero. If so, it indicates that there is no flexibility resource deficit, and both system flexibility resources and transmission channels are sufficient. Otherwise, it indicates that there is a flexibility resource deficit. Then, it further compares the sum of the total flexibility supply of all nodes with the sum of the flexibility demand of all nodes. If the sum of the total flexibility supply of all nodes is greater than the sum of the flexibility demand of all nodes, it indicates that system flexibility resources are sufficient but transmission channels are insufficient. If the sum of the total flexibility supply of all nodes is less than the sum of the flexibility demand of all nodes, it further determines whether the absolute value of the virtual active power flow load rate of the line is equal to 1. If so, it indicates that both system flexibility resources and system transmission channels are insufficient; otherwise, it indicates that system flexibility resources are insufficient but transmission channels are sufficient.

[0200] Thirdly, the present invention provides a power system flexibility assessment device that takes into account resource transmission characteristics. The power system flexibility assessment device includes a memory and a processor. The memory is used to store computer program code and transmit the computer program code to the processor. The processor is used to execute the aforementioned power system flexibility assessment method according to the instructions in the computer program code.

[0201] Thirdly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned power system flexibility assessment method.

[0202] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0203] 1. The power system flexibility assessment method considering resource transmission characteristics described in this invention first establishes a system operation model with minimizing the total system cost as the optimization objective. Then, based on load and renewable energy output forecast data, the system operation model is solved to obtain the system operation state. Based on the system operation state, the flexibility resource deficit is calculated, and the system flexibility assessment is achieved based on the flexibility resource deficit. The above design sets transmission constraints on the supply and demand balance of flexibility resources by the system transmission channels when constructing the system operation model, fully considering the transmission capacity limitations of the system transmission channels, thereby improving the accuracy of the flexibility assessment results.

[0204] 2. The power system flexibility assessment method that takes into account resource transmission characteristics described in this invention, when setting transmission constraints on the supply and demand balance of flexibility resources in the system transmission channel, not only considers the situation that various power source-side flexibility resources may not be fully utilized in actual scheduling, but also takes into account the actual operating conditions, which significantly improves the accuracy and practicality of the flexibility assessment results. Furthermore, it introduces a virtual power flow at the net load boundary to simulate the flexibility balance state of the system under extreme scenarios. The virtual power flow strictly follows the physical constraints of the system, thereby achieving accurate characterization and effective coverage of the worst operating conditions.

[0205] 3. The power system flexibility assessment method that takes into account resource transmission characteristics described in this invention can not only quantify the flexibility deficit value through flexibility assessment, but also determine whether the cause of the flexibility deficit is insufficient node flexibility resources or insufficient system transmission channels, thereby providing a basis for system operation and planning. Attached Figure Description

[0206] Figure 1 This is a flowchart illustrating the power system flexibility considering resource transmission characteristics as described in this invention.

[0207] Figure 2 This is a topology diagram of the IEEE standard 39-node system used in the examples of this invention.

[0208] Figure 3 The 24-hour predicted data of load and new energy output used in the calculation examples of this invention are as follows.

[0209] Figure 4 This is a schematic diagram showing the 24-hour flexibility resource supply and demand balance result of node 20 in the IEEE standard 39-node system used in the example of this invention.

[0210] Figure 5 This is a block diagram of the power system flexibility assessment system that takes into account resource transmission characteristics, as described in this invention.

[0211] Figure 6 This is a structural block diagram of the power system flexibility assessment device that takes into account resource transmission characteristics, as described in this invention. Detailed Implementation

[0212] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0213] Example 1:

[0214] See Figure 1 A method for assessing the flexibility of a power system that takes into account resource transmission characteristics is performed in the following steps:

[0215] S1. Establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints of the system transmission channel on the supply and demand balance of flexibility resources.

[0216] Specifically, the total system cost includes the system's thermal power generation cost, renewable energy curtailment penalty cost, load shedding penalty cost, and virtual flexibility deficiency penalty cost at the net load boundary; the objective function expression of the system operation model is as follows:

[0217] ;

[0218] ;

[0219] ;

[0220] ;

[0221] ;

[0222] In the above formula, The total cost of the power system; , , These are the power generation costs of thermal power units, the penalty costs for abandoning new energy sources, and the penalty costs for load shedding; , These are the penalty costs for insufficient virtual flexibility at the upper and lower boundaries of the system net load, respectively. , They are respectively Time Node Insufficient virtual flexibility at the upper and lower boundaries of net load incurs penalty costs. , They are respectively Time Node The balance between supply and demand of flexibility resources at the upper and lower boundaries of net load; , , All are thermal power units The power generation cost coefficient; for Typical scenarios Lower thermal power unit ; output power; , These are the cost coefficients for abandoning new energy sources and the cost coefficients for load shedding, respectively. , They are respectively Time Node The maximum output power and actual absorption power of new energy sources; , They are respectively Time Node The required power supply and the actual power supply; , , These are respectively thermal power units, new energy sources, and system node sets; , The penalties for insufficient flexibility are adjusted upwards and downwards, respectively. The scheduling period; This represents the number of system nodes.

[0223] This invention introduces , The purpose is solely to assess whether the system still suffers from a lack of flexibility even after utilizing all flexibility resources; therefore, the following constraints must also be met: , ; This indicates that it is much smaller than.

[0224] Specifically, the transmission constraints of the system transmission channels on the supply and demand balance of flexible resources include the transmission constraints of the system transmission channels at the upper and lower boundaries of the net load on the supply and demand balance of flexible resources; the construction methods of the transmission constraints of the system transmission channels at the upper and lower boundaries of the net load on the supply and demand balance of flexible resources are the same; taking the upper boundary of the net load as an example, the transmission constraints of the system transmission channels at the upper boundary of the net load on the supply and demand balance of flexible resources include: considering system nodes at the upper boundary of the net load Nodes that actually utilize flexible resources Virtual net power constraints, net load upper boundary except for nodes Virtual net power constraints and net load upper boundaries at other nodes of the external system are passed through system nodes. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The flexibility of resource requirements is constrained.

[0225] Specifically, the system node at the upper boundary of the net load The virtual net power constraints include:

[0226] ;

[0227] In the above formula, At the upper boundary Time Node Virtual net power, superscript This indicates the introduction of virtual quantities, making it easier to distinguish them from actual system quantities; for Time Node The upper boundary of net load; , , , They are respectively Time Node The output of thermal power units, the output of hydropower units, the power generation of pumped storage units, and the pumping power of pumped storage units; , , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units, hydropower units, and pumped storage units used;

[0228] The system at the upper boundary of the net load, excluding nodes The virtual net power constraints for other nodes include:

[0229] ;

[0230] ;

[0231] ;

[0232] ;

[0233] In the above formula, , At the upper boundary Time Branch Branch roads Virtual active power flow; , Representing the nodes respectively A set of connected first and last nodes; , At the upper boundary Time Node ,node The virtual node voltage phase angle; branch road The per-unit value of reactance; , They are nodes The upper and lower limits of the voltage phase angle; branch road The capacity of the transmission lines;

[0234] The upper boundary of the net load is reached through the system node. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The constraints on flexibility and resource requirements include:

[0235] ;

[0236] ;

[0237] In the above formula, Node at the upper bound The total amount of flexible supply; For nodes transmitted via lines Total amount of flexible resources; For the upper boundary Time Node The actual trend.

[0238] Specifically, the system operation constraints include power flow balance constraints, line capacity constraints, thermal power unit output constraints, hydropower unit output constraints, pumped storage unit operation constraints, node voltage phase angle constraints, and actual utilization constraints of flexibility resources.

[0239] The power flow balance constraints include:

[0240] ;

[0241] In the above formula, , , , These are the output vectors of thermal power units, hydropower units, new energy units, and nodal load vectors, respectively. , These are the pumped-storage unit power vector and the pumping power vector, respectively. , These are the node admittance matrix and the node voltage phase angle vector, respectively.

[0242] The line capacity constraints include:

[0243] ;

[0244] In the above formula, , They are respectively Timetable The actual active power flow and transmission limit;

[0245] The power output constraints of the thermal power unit include:

[0246] ;

[0247] In the above formula, , They are respectively time, Time Node The output of thermal power units; They are respectively thermal power units ; output power; , thermal power units The upper and lower limits of output; , thermal power units The rate of upward and downward climbing; The scheduling time interval;

[0248] The hydropower output constraints include hydropower station constraints and hydropower unit constraints. The hydropower station constraints include hydraulic connection constraints, water level constraints, outflow constraints, hydropower station output constraints, water level-reservoir capacity relationship constraints, and tailrace level-discharge relationship constraints. The hydraulic connection constraints include:

[0249] ;

[0250] ;

[0251] ;

[0252] In the above formula, , For hydroelectric power station exist time, Storage capacity at any given time; For hydroelectric power station exist Inbound traffic at any given time; For hydroelectric power station exist Real-time outbound flow; For hydroelectric power station With its upstream hydropower station Water flow stagnation time; To take into account the water flow lag time of the hydropower station During the period Outbound flow; For hydroelectric power station With its upstream hydropower station Between Interval flow at any given time; , Hydropower stations Pumped storage units The flow rate of water pumping and power generation at any given time; , Hydropower stations exist Real-time power generation and water discharge flow;

[0253] The water level constraints include:

[0254] ;

[0255] ;

[0256] In the above formula, For hydroelectric power station In the reservoir The water level in front of the dam at any given time. , Hydropower stations The upper and lower limits of the water level in front of the dam of the reservoir; For hydroelectric power station Initial water level during the scheduling period;

[0257] The outbound flow constraints include:

[0258] ;

[0259] In the above formula, For hydroelectric power station exist Real-time outbound flow; , Hydropower stations The upper and lower limits of outbound flow;

[0260] The power output constraints of the hydropower station include:

[0261] ;

[0262] In the above formula, For hydroelectric power station exist Total output at any given moment; , Hydropower stations The upper and lower limits of output;

[0263] The constraints on the relationship between water level and reservoir capacity include:

[0264] ;

[0265] In the above formula, For hydroelectric power station exist Storage capacity at any given time; For hydroelectric power station The nonlinear relationship curve function between water level and reservoir capacity of the reservoir is shown in the figure.

[0266] The constraints on the relationship between tailwater level and discharge volume include:

[0267] ;

[0268] In the above formula, For hydroelectric power station exist The tailwater level at that moment; For hydroelectric power station The nonlinear relationship curve function between tailwater level and discharge capacity;

[0269] The water level constraints include unit output constraints, unit power generation flow constraints, unit output ramp-up constraints, unit power generation head constraints, and unit dynamic characteristic constraints; the unit output constraints include:

[0270] ;

[0271] ;

[0272] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Efforts made at all times; , Hydropower stations The The upper and lower limits of the output of the hydroelectric generator unit; For hydroelectric power station The total number of hydropower units included; For hydroelectric power station contribution;

[0273] The unit's power generation flow constraints include:

[0274] ;

[0275] ;

[0276] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Power generation flow rate at any given moment; , Hydropower stations The The upper and lower limits of the power generation flow of the hydroelectric generating unit in Taiwan;

[0277] The unit output ramp-up constraints include:

[0278] ;

[0279] In the above formula, , Hydropower stations The Taiwan hydroelectric power unit time, Efforts made at all times; For hydroelectric power station The The hill-climbing ability of the hydroelectric generator unit;

[0280] The generator head constraint includes:

[0281] ;

[0282] In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit The constant head of the generator; , Hydropower stations The reservoir is located in time, The water level in front of the dam at any given time;

[0283] The unit dynamic characteristic constraints include:

[0284] ;

[0285] In the above formula, For hydroelectric power station The The nonlinear relationship between the output of the hydroelectric generator unit and the power generation flow rate and power generation head;

[0286] The operating constraints of the pumped storage unit include:

[0287] ;

[0288] ;

[0289] ;

[0290] ;

[0291] ;

[0292] ;

[0293] ;

[0294] In the above formula, , Hydropower stations The pumping and power generation flow of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The real-time status of pumping and power generation; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation capacity at any given time; , , , Hydropower stations The Minimum pumping power, maximum pumping power, minimum generating power, and maximum generating power of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation flow rates at any given time; , These are the pumping and power generation efficiencies of a single pumped-storage unit, respectively. , These are the average density of water and the acceleration due to gravity, respectively. For hydroelectric power station The average head; For hydroelectric power station The number of pumped storage units;

[0295] The node voltage phase angle constraint includes:

[0296] ;

[0297] In the above formula, For nodes exist Voltage phase angle at any given moment; , These represent the maximum and minimum values ​​of the node voltage phase angle, respectively. For the system node set;

[0298] The actual usage constraints of the flexibility resources include the actual usage constraints of thermal power units, hydropower units, and pumped storage units. The actual usage constraints of thermal power units include:

[0299] ;

[0300] ;

[0301] ;

[0302] ;

[0303] In the above formula, In response The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units dispatched; , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of power units that can be deployed is provided to ensure flexibility in adjusting power supply and demand. , It is a 0-1 variable used to limit the thermal power unit to only be able to call up or down the flexibility adjustment capability at the same time, and the actual amount called up cannot exceed the available supply. , They are nodes The flexibility of adjusting the power supply to the upper and lower limits of thermal power units can be improved.

[0304] S2. Solve the system operation model based on load and new energy output forecast data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize the system flexibility assessment based on the flexibility resource deficit.

[0305] Specifically, the solution steps for the system operation model include: nonlinear equality constraints of the piecewise linearized model, including water level-reservoir capacity relationship constraints and tailrace water level-discharge relationship constraints; linearizing the unit dynamic characteristic constraints using the McCormick convex hull relaxation method; and solving the system operation model in MATLAB software by calling the Gurobi solver to obtain the system operation results, which include the output and operating status of thermal power units, hydropower units, pumped storage units, the absorption of new energy sources (wind power and photovoltaic), the system load shedding, the flexibility resource shortage for node upswing and downswing, and the virtual active power flow of the transmission lines.

[0306] Specifically, the formula for calculating the flexibility resource shortage is as follows:

[0307] ;

[0308] ;

[0309] ;

[0310] ;

[0311] In the above formula, , They are respectively Time Node The upward and downward adjustment of flexibility resources shortage; , They are respectively Time Node The balance between supply and demand of flexible resources at the upper and lower boundaries; , These are the nodes at the upper and lower boundaries, respectively. The actual total amount of flexible resource supply used; , They are respectively Time Node The need for flexibility resources at the upper and lower boundaries.

[0312] Specifically, the system flexibility assessment based on flexibility resource shortage includes: first, determining whether the sum of the system flexibility resource shortages of all nodes is zero. If so, it indicates that there is no flexibility resource shortage problem in the system, and the system flexibility resources and system transmission channels are sufficient. Otherwise, it indicates that there is a flexibility resource shortage problem in the system. Then, it further compares the sum of the total flexibility supply of all nodes with the sum of the flexibility demand of all nodes. If the sum of the total flexibility supply of all nodes is greater than the sum of the flexibility demand of all nodes, it indicates that the system flexibility resources are sufficient but the transmission channels are insufficient. If the sum of the total flexibility supply of all nodes is less than the sum of the flexibility demand of all nodes, it further determines whether there is an absolute value of the line virtual active power flow load rate equal to 1. If so, it indicates that both the system flexibility resources and system transmission channels are insufficient. Otherwise, it indicates that the system flexibility resources are insufficient but the transmission channels are sufficient. When a system experiences a flexibility deficit and the absolute value of the virtual active power flow load rate of a certain line equals 1, it indicates that the transmission capacity of that line has been fully utilized. Due to insufficient transmission channel capacity, flexible resources cannot be further transmitted, resulting in insufficient system transmission channels. When a system experiences a flexibility deficit and the absolute value of the virtual active power flow load rate of all lines is less than 1, it indicates that all lines still have transmission margin, and the lines can further transmit flexible resources, but are limited by insufficient flexible resources. See Table 1, which uses an example of adjusting the system's flexibility deficit to illustrate the system flexibility assessment rules:

[0313] Table 1 System Flexibility Assessment Rules

[0314]

[0315] In the above table, For nodes exist The total amount of flexible supply at any time, For nodes exist The need for flexibility at any time This represents the total number of system nodes. For the line The virtual active power load factor is calculated using the following formula: , for Timetable Virtual active current, For the line The transmission limit.

[0316] Performance verification:

[0317] The examples were performed on the IEEE standard 39-node system; see [link / reference]. Figure 2 The IEEE standard 39-bus system comprises four thermal power units with a total installed capacity of 2586MW, two hydropower stations with a total installed capacity of eight hydropower units, and four additional pumped-storage units at the two hydropower stations, bringing the total installed capacity to 400MW. The total installed capacity of wind power is 1977MW, and the total installed capacity of photovoltaic power is 1150MW, resulting in a renewable energy penetration rate of 35.7%. 24-hour load and renewable energy output forecast data are as follows: Figure 3 As shown. Taking node 20 of the system as an example, the supply and demand balance of its flexibility resources within 24 hours is plotted as follows. Figure 4 As shown. By Figure 4 It can be seen that the flexibility resources provided by the line transmission and the flexibility resources of the calling node itself jointly meet the node's flexibility requirements. Under power flow constraints, the actual flexibility resources called by the node will not exceed the maximum flexibility resources it possesses. Table 2 shows the calculated times when the system experiences a flexibility deficit and their corresponding values. This deficit is mainly due to increased load and reduced photovoltaic power during the evening peak, requiring increased controllable power output to maintain system power balance. Table 3 shows the calculated flexibility resource demand and total flexibility supply at each time point. Table 4 shows the times when the absolute value of the virtual active power flow load rate of the line equals 1 and their corresponding line numbers.

[0318] Table 2 Flexibility deficit of the system at different times

[0319]

[0320] Table 3. Increased flexibility resource demand and total flexibility supply at different times in the system.

[0321]

[0322] Table 4. Times when the absolute value of the virtual active power flow load rate equals 1 and their corresponding line numbers.

[0323]

[0324] Table 2 shows that the system has a flexibility deficit. Table 3 shows that the total supply of flexibility resources exceeds the demand for flexibility resources. Combined with the evaluation rules in Table 1, this indicates that the system has sufficient flexibility resources but insufficient transmission channels. After calculating the virtual active power flow load factor, Table 4 shows that some lines in the system have a virtual active power flow load factor of 1. This further illustrates that the flexibility deficit is caused by insufficient system channel transmission capacity, preventing these flexibility resources from being delivered to nodes with flexibility needs, thus leading to risk events such as load shedding. Therefore, the solution should focus on upgrading and transforming the lines corresponding to a virtual active power flow load factor of 1. In summary, the power system flexibility assessment described in this invention fully considers the impact of system transmission channels on achieving a balance between flexibility supply and demand, making the flexibility assessment results more consistent with the actual operating characteristics of the system. It can not only quantify the flexibility deficit value but also pinpoint the cause of the flexibility deficit problem, providing a basis for system operation and planning.

[0325] Example 2:

[0326] See Figure 5 A power system flexibility assessment system that takes into account resource transmission characteristics includes a model building module and a flexibility assessment module;

[0327] Specifically, the model building module is used to establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints on the supply and demand balance of flexible resources via the system transmission channels. Specifically, the transmission constraints on the supply and demand balance of flexible resources via the system transmission channels at the upper and lower boundaries of the net load include the transmission constraints on the supply and demand balance of flexible resources via the system transmission channels at the upper boundary of the net load. The transmission constraints on the supply and demand balance of flexible resources via the system transmission channels at the upper boundary of the net load include: considering system nodes at the upper boundary of the net load. Nodes that actually utilize flexible resources Virtual net power constraints, net load upper boundary except for nodes Virtual net power constraints and net load upper boundaries at other nodes of the external system are passed through system nodes. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The system's flexibility resource demand constraints are the same as those in Example 1 and will not be repeated here. Specifically, the total system cost includes the system's thermal power generation cost, renewable energy curtailment penalty cost, load shedding penalty cost, and virtual flexibility deficiency penalty cost at the net load boundary. The objective function expression of the system operation model is the same as that in Example 1 and will not be repeated here. The system operation constraints include power flow balance constraints, line capacity constraints, thermal power unit output constraints, hydropower unit output constraints, pumped storage unit operation constraints, node voltage phase angle constraints, and actual utilization constraints of flexibility resources. The actual utilization constraints of flexibility resources include the actual utilization constraints of thermal power units, hydropower units, and pumped storage units. The specific expressions of these constraints are the same as those in Example 1 and will not be repeated here. The flexibility assessment module is used to solve the system operation model based on load and renewable energy output prediction data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize system flexibility assessment based on the flexibility resource deficit. Specifically, the calculation formula for the flexibility resource deficit is the same as that in Example 1 and will not be repeated here.

[0328] Specifically, the flexibility assessment module is used to assess system flexibility according to the following steps: It determines whether the sum of the system flexibility resource deficits of all nodes is zero. If so, it indicates that there is no system flexibility resource deficit, and both system flexibility resources and system transmission channels are sufficient. Otherwise, it indicates that there is a system flexibility resource deficit. Then, it further compares the sum of the total flexibility supply of all nodes with the sum of the flexibility demand of all nodes. If the sum of the total flexibility supply of all nodes is greater than the sum of the flexibility demand of all nodes, it indicates that system flexibility resources are sufficient but transmission channels are insufficient. If the sum of the total flexibility supply of all nodes is less than the sum of the flexibility demand of all nodes, it further determines whether the absolute value of the virtual active power flow load rate of the line is equal to 1. If so, it indicates that both system flexibility resources and system transmission channels are insufficient; otherwise, it indicates that system flexibility resources are insufficient but transmission channels are sufficient.

[0329] Example 3:

[0330] See Figure 6 A power system flexibility assessment device that takes into account resource transmission characteristics, the power system flexibility assessment device includes a memory and a processor; the memory is used to store computer program code and transmit the computer program code to the processor; the processor is used to execute the aforementioned power system flexibility assessment method according to the instructions in the computer program code.

[0331] Example 4:

[0332] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned power system flexibility assessment method.

[0333] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program goods. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program goods embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0334] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0335] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0336] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0337] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for assessing the flexibility of a power system taking into account resource transmission characteristics, characterized in that: The power system flexibility assessment method includes: S1. Establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints of the system transmission channel on the supply and demand balance of flexible resources. S2. Solve the system operation model based on load and new energy output forecast data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize the system flexibility assessment based on the flexibility resource deficit.

2. The power system flexibility assessment method considering resource transmission characteristics according to claim 1, characterized in that: The transmission constraints of the system transmission channel on the supply and demand balance of flexible resources include the transmission constraints of the system transmission channel at the upper and lower boundaries of the net load on the supply and demand balance of flexible resources; the transmission constraints of the system transmission channel at the upper boundary of the net load on the supply and demand balance of flexible resources include: considering system nodes at the upper boundary of the net load. Nodes that actually utilize flexible resources Virtual net power constraints, net load upper boundary except for nodes Virtual net power constraints and net load upper boundaries at other nodes of the external system are passed through system nodes. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The flexibility of resource requirements is constrained.

3. The power system flexibility assessment method considering resource transmission characteristics according to claim 1, characterized in that: The total system cost includes the system's thermal power generation cost, renewable energy curtailment penalty cost, load shedding penalty cost, and virtual flexibility deficiency penalty cost at the net load boundary; the objective function expression of the system operation model is as follows: ； ； ； ； ； In the above formula, The total cost of the power system; , , These are the power generation costs of thermal power units, the penalty costs for abandoning new energy sources, and the penalty costs for load shedding; , These are the penalty costs for insufficient virtual flexibility at the upper and lower boundaries of the system net load, respectively. , They are respectively Time Node Insufficient virtual flexibility at the upper and lower boundaries of net load incurs penalty costs. , They are respectively Time Node The balance between supply and demand of flexibility resources at the upper and lower boundaries of net load; , , All are thermal power units The power generation cost coefficient; for Typical scenarios Lower thermal power unit ; output power; , These are the cost coefficients for abandoning new energy sources and the cost coefficients for load shedding, respectively. , They are respectively Time Node The maximum output power and actual absorption power of new energy sources; , They are respectively Time Node The required power supply and the actual power supply; , , These are respectively thermal power units, new energy sources, and system node sets; , The penalties for insufficient flexibility in adjusting upward and downward adjustments are respectively: The scheduling period; This represents the number of system nodes.

4. The power system flexibility assessment method considering resource transmission characteristics according to claim 2, characterized in that: System node at the upper boundary of the net load The virtual net power constraints include: ； In the above formula, At the upper boundary Time Node Virtual net power, superscript This indicates the introduction of virtual quantities, making it easier to distinguish them from actual system quantities; for Time Node The upper boundary of net load; , , , They are respectively Time Node The output of thermal power units, the output of hydropower units, the power generation of pumped storage units, and the pumping power of pumped storage units; , , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units, hydropower units, and pumped storage units used; The system at the upper boundary of the net load, excluding nodes The virtual net power constraints for other nodes include: ； ； ； ； In the above formula, , At the upper boundary Time Branch Branch roads Virtual active power flow; , Representing the nodes respectively A set of connected first and last nodes; , At the upper boundary Time Node ,node The virtual node voltage phase angle; branch road The per-unit value of reactance; , They are nodes The upper and lower limits of the voltage phase angle; branch road The capacity of the transmission lines; The upper boundary of the net load is reached through the system node. The node's own flexibility resources or the flexibility resources transmitted to other nodes through the line together satisfy the node's needs. The constraints on flexibility and resource requirements include: ； ； In the above formula, Node at the upper bound The total amount of flexible supply; For nodes transmitted via lines Total amount of flexible resources; For the upper boundary Time Node The actual trend.

5. The power system flexibility assessment method considering resource transmission characteristics according to claim 1, characterized in that: The formula for calculating the shortage of flexibility resources is as follows: ； ； ； ； In the above formula, , They are respectively Time Node The upward and downward adjustment of flexibility resources shortage; , They are respectively Time Node The balance between supply and demand of flexible resources at the upper and lower boundaries; , These are the nodes at the upper and lower boundaries, respectively. The actual total amount of flexible resource supply used; , respectively Time Node The need for flexibility resources at the upper and lower boundaries.

6. The power system flexibility assessment method considering resource transmission characteristics according to claim 1, characterized in that: The system operation constraints include power flow balance constraints, line capacity constraints, thermal power unit output constraints, hydropower unit output constraints, pumped storage unit operation constraints, node voltage phase angle constraints, and actual utilization constraints of flexibility resources. The power flow balance constraints include: ； In the above formula, , , , These are the output vectors of thermal power units, hydropower units, new energy units, and nodal load vectors, respectively. , These are the pumped-storage unit power vector and the pumping power vector, respectively. , These are the node admittance matrix and the node voltage phase angle vector, respectively. The line capacity constraints include: ； In the above formula, , They are respectively Timetable The actual active power flow and transmission limit; The power output constraints of the thermal power unit include: ； In the above formula, , They are respectively time, Time Node The output of thermal power units; They are respectively thermal power units ; output power; , thermal power units The upper and lower limits of output; , thermal power units The rate of upward and downward climbing; The scheduling time interval; The hydropower output constraints include hydropower station constraints and hydropower unit constraints. The hydropower station constraints include hydraulic connection constraints, water level constraints, outflow constraints, hydropower station output constraints, water level-reservoir capacity relationship constraints, and tailrace level-discharge relationship constraints. The hydraulic connection constraints include: ； ； ； In the above formula, , For hydroelectric power station exist time, Storage capacity at any given time; For hydroelectric power station exist Inbound traffic at any given time; For hydroelectric power station exist Real-time outbound flow; For hydroelectric power station With its upstream hydropower station Water flow stagnation time; To take into account the water flow lag time of the hydropower station During the period Outbound flow; For hydroelectric power station With its upstream hydropower station Between Interval flow at any given time; , Hydropower stations Pumped storage units The flow rate of water pumping and power generation at any given time; , Hydropower stations exist Real-time power generation and water discharge flow; The water level constraints include: ； ； In the above formula, For hydroelectric power station In the reservoir The water level in front of the dam at any given time. , Hydropower stations The upper and lower limits of the water level in front of the dam of the reservoir; For hydroelectric power station Initial water level during the scheduling period; The outbound flow constraints include: ； In the above formula, For hydroelectric power station exist Real-time outbound flow; , Hydropower stations The upper and lower limits of outbound flow; The power output constraints of the hydropower station include: ； In the above formula, For hydroelectric power station exist Total output at any given moment; , Hydropower stations The upper and lower limits of output; The constraints on the relationship between water level and reservoir capacity include: ； In the above formula, For hydroelectric power station exist Storage capacity at any given time; For hydroelectric power station The nonlinear relationship curve function between water level and reservoir capacity of the reservoir is shown in the figure. The constraints on the relationship between tailwater level and discharge volume include: ； In the above formula, For hydroelectric power station exist The tailwater level at that moment; For hydroelectric power station The nonlinear relationship curve function between tailwater level and discharge capacity; The water level constraints include unit output constraints, unit power generation flow constraints, unit output ramp-up constraints, unit power generation head constraints, and unit dynamic characteristic constraints; the unit output constraints include: ； ； In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit Efforts made at all times; , Hydropower stations The The upper and lower limits of the output of the hydroelectric generator unit; For hydroelectric power station The total number of hydropower units included; For hydroelectric power station contribution; The unit's power generation flow constraints include: ； ； In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit The power generation flow rate at any given moment; , Hydropower stations The The upper and lower limits of the power generation flow of the hydroelectric generating unit in Taiwan; The unit output ramp-up constraints include: ； In the above formula, , Hydropower stations The Taiwan hydroelectric power unit time, Efforts made at all times; For hydroelectric power station The The hill-climbing ability of the hydroelectric generator unit; The generator head constraint includes: ； In the above formula, For hydroelectric power station The Taiwan hydroelectric power unit The constant head of the generator; , Hydropower stations The reservoir is located in time, The water level in front of the dam at any given time; The unit dynamic characteristic constraints include: ； In the above formula, For hydroelectric power station The The nonlinear relationship between the output of the hydroelectric generator unit and the power generation flow rate and power generation head; The operating constraints of the pumped-storage unit include: ； ； ； ； ； ； ； In the above formula, , Hydropower stations The pumping and power generation flow of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The real-time status of pumping and power generation; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation capacity at any given time; , , , Hydropower stations The Minimum pumping power, maximum pumping power, minimum generating power, and maximum generating power of the pumped storage unit; , Hydropower stations The Taiwan pumped storage unit The pumping and power generation flow rates at any given time; , These are the pumping and power generation efficiencies of a single pumped-storage unit, respectively. , These are the average density of water and the acceleration due to gravity, respectively. For hydroelectric power station The average head; For hydroelectric power station The number of pumped storage units; The node voltage phase angle constraint includes: ； In the above formula, For nodes exist Voltage phase angle at any given moment; , These represent the maximum and minimum values ​​of the node voltage phase angle, respectively. For the system node set; The actual usage constraints of the flexibility resources include the actual usage constraints of thermal power units, hydropower units, and pumped storage units. The actual usage constraints of thermal power units include: ； ； ； ； In the above formula, In response The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of thermal power units dispatched; , These are respectively represented as responses The flexibility requirements of the time-based system at the upper bound, nodes The actual amount of power units that can be deployed for both upward and downward adjustments is provided; , It is a 0-1 variable used to limit the thermal power unit to only be able to call up or down the flexibility adjustment capability at the same time, and the actual amount called up cannot exceed the available supply. , They are nodes The flexibility of adjusting the power supply of thermal power units can be improved.

7. The power system flexibility assessment method considering resource transmission characteristics according to claim 1, characterized in that: The system flexibility assessment based on flexibility resource shortage includes: determining whether the sum of the system flexibility resource shortages of all nodes is zero. If so, it indicates that there is no flexibility resource shortage problem in the system, and the system flexibility resources and system transmission channels are sufficient. Otherwise, it indicates that there is a flexibility resource shortage problem in the system. Then, it further compares the sum of the total flexibility supply of all nodes with the sum of the flexibility demand of all nodes. If the sum of the total flexibility supply of all nodes is greater than the sum of the flexibility demand of all nodes, it indicates that the system flexibility resources are sufficient but the transmission channels are insufficient. If the sum of the total flexibility supply of all nodes is less than the sum of the flexibility demand of all nodes, it further determines whether there is an absolute value of the line virtual active power flow load rate equal to 1. If so, it indicates that both the system flexibility resources and system transmission channels are insufficient. Otherwise, it indicates that the system flexibility resources are insufficient but the transmission channels are sufficient.

8. A power system flexibility assessment system considering resource transmission characteristics, characterized in that: The power system flexibility assessment system is based on the power system flexibility assessment method of claim 1, and the system includes a model building module and a flexibility assessment module. The model building module is used to establish a system operation model with the optimization objective of minimizing the total system cost. The constraints of the system operation model include system operation constraints and transmission constraints of the system transmission channel on the supply and demand balance of flexible resources. The flexibility assessment module is used to solve the system operation model based on load and new energy output forecast data to obtain the system operation status, calculate the flexibility resource deficit based on the system operation status, and realize the system flexibility assessment based on the flexibility resource deficit.

9. A power system flexibility assessment device considering resource transmission characteristics, characterized in that: The power system flexibility assessment device includes a memory and a processor; the memory is used to store computer program code and transmit the computer program code to the processor; the processor is used to execute the power system flexibility assessment method as described in claim 1 according to the instructions in the computer program code.

10. A computer-readable storage medium storing a computer program that, when executed by a processor, implements the power system flexibility assessment method as described in claim 1.

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