Power grid planning operation safety margin assessment method and device, electronic equipment and medium

Abstract

The invention discloses a power grid planning operation safety margin assessment method and device, electronic equipment and a medium, and is used for solving the problem that the assessment is not accurate enough because an operation mode with the maximum power grid operation margin cannot be obtained because the consideration is not comprehensive when the power grid planning operation safety margin assessment is carried out at present. The method comprises the steps of performing optimal scheduling on a to-be-evaluated power grid to obtain an optimal power grid scheduling result; according to the optimal power grid dispatching result, the element load rate of each element device in the to-be-evaluated power grid and the section load rate of each operation control section are calculated based on mirror symmetry; calculating an element load uniformity index according to the load rate of each element, and calculating a section operation safety margin index according to the load rate of each section; and based on the element load uniformity index and the section operation safety margin index, evaluating the power grid operation safety margin level of the to-be-evaluated power grid as a scheme evaluation index during power grid planning of the to-be-evaluated power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power system dispatching, and in particular to a method, device, electronic equipment and medium for evaluating the safety margin of power grid planning and operation. Background Art

[0002] As the scale of the power system continues to expand, the vigorous development of new power systems has driven a high penetration rate of renewable energy, making it gradually become the main source of power supply. This transformation has posed unprecedented challenges to the safe operation of the power grid.

[0003] For the safe operation of the power grid, particular attention must be paid to its operational safety margin. This is because renewable energy output is significantly driven by meteorological characteristics, exhibiting not only strong randomness and volatility within the day but also intermittent periods of varying duration with seasonal changes. This process gradually shifts the system balance from one driven by source and load to a complex equilibrium involving multiple actors interacting: source, grid, load, and storage. In new power systems with a high proportion of renewable energy, renewable energy power fluctuates significantly within the day. At some wind farms, output can fluctuate by as much as 20% of installed capacity within a single hour, and in extreme cases, as much as 38%. Such large fluctuations in renewable energy output can cause sections of the grid to operate at their limits for extended periods. Furthermore, in a market environment where power equipment requires frequent adjustments or prolonged high-load operation, the risk of equipment failure continues to increase. Therefore, considering the operational safety margin of the power grid from the perspective of grid operation and dispatch in this power market environment is particularly urgent and important.

[0004] Currently, optimization scheduling primarily considers minimizing economic costs or maximizing social welfare, while also addressing the corresponding grid safety constraints. However, the scale of actual power grids is large, and the potential for optimization is vast. However, due to time constraints, only suboptimal solutions can be obtained within a certain convergence error or set solution time threshold. In some special cases, the problem itself has multiple solutions, and commercial solvers can only obtain one valid solution among them. While economic efficiency is guaranteed in these cases, multiple actual grid operating modes may exist at the same economic level. Therefore, identifying the operating mode that maximizes the grid's operating margin under these multiple possible operating modes warrants further investigation. Summary of the Invention

[0005] The present invention provides a method, device, electronic device and medium for evaluating the safety margin of power grid planning and operation, which are used to solve or partially solve the technical problem that the current evaluation of the safety margin of power grid planning and operation is not comprehensive enough, thus failing to obtain the operating mode with the maximum power grid operation margin, resulting in inaccurate evaluation.

[0006] The present invention provides a method for evaluating the safety margin of power grid planning and operation, the method comprising:

[0007] Optimize the dispatch of the power grid to be evaluated and obtain the optimal grid dispatch result;

[0008] According to the optimal grid dispatch result, the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section are calculated based on mirror symmetry;

[0009] Calculating the component load uniformity index based on the component load rate, and calculating the section operation safety margin index based on the section load rate;

[0010] Based on the component load uniformity index and the section operation safety margin index, the grid operation safety margin level of the grid to be evaluated is evaluated, and the grid operation safety margin level is used as a scheme evaluation index when performing grid planning for the grid to be evaluated.

[0011] Optionally, performing optimal scheduling on the power grid to be evaluated to obtain an optimal power grid scheduling result includes:

[0012] Constructing unit start-up and shutdown state association constraints, unit minimum start-up and shutdown time constraints, unit output range constraints, unit ramp rate constraints, line transmission capacity constraints, node phase angle constraints, node power balance constraints, wind power-photovoltaic output constraints, energy storage operation constraints, operation control section constraints and line Nk constraints as multiple constraints of the power grid to be evaluated;

[0013] Taking minimizing the grid operation cost, wind curtailment penalty cost, solar curtailment penalty cost and load loss penalty cost as the optimization goal, an optimization objective function of the grid to be evaluated is constructed;

[0014] Constructing a scheduling optimization model according to the optimization objective function and the multiple constraints;

[0015] The dispatch optimization model is iteratively optimized and solved to obtain the optimal grid dispatch result of the grid to be evaluated.

[0016] Optionally, the iterative optimization and solving of the scheduling optimization model to obtain an optimal grid scheduling result of the power grid to be evaluated includes:

[0017] The scheduling optimization model is divided into a main problem and a series of sub-problems based on Benders decomposition, and the main problem and a series of sub-problems are repeatedly iteratively solved until the preset convergence conditions are met, thereby obtaining the power grid scheduling result under the optimal scheduling condition.

[0018] Optionally, the optimal grid dispatch result includes a first actual load power value of each component device in the grid to be evaluated and a second actual load power value of each operation control section; and the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section are calculated based on mirror symmetry according to the optimal grid dispatch result, including:

[0019] For each of the component devices, performing a mirror-symmetric calculation according to the first actual load power value, the first preset load power lower limit value, and the first preset load power upper limit value to obtain a component load rate of the component device;

[0020] For each of the operation control sections, a mirror-symmetric calculation is performed according to the second actual load power value, the second preset load power lower limit value, and the second preset load power upper limit value to obtain the section load rate of the operation control section.

[0021] Optionally, the process of performing a mirror-symmetric calculation on the component equipment to obtain the component load rate, or performing a mirror-symmetric calculation on the operation control section to obtain the section load rate, includes:

[0022] For the target load factor Any target actual load power value , the target actual load power value The corresponding target preset load power lower limit and target preset load power upper limit Make numerical judgments;

[0023] when When: If ,but ;like ,but ;

[0024] when When: If ,but ;like ,but ;

[0025] when and When: If ,but ;like ,but .

[0026] Optionally, calculating the component load uniformity index according to the component load rate includes:

[0027] Calculating the average load rate of the components by using the mean value method according to the load rates of the components;

[0028] Calculate the standard deviation of the component load rate and each component load rate to obtain a component load rate difference value;

[0029] Based on the component load rate difference degree value, a component load uniformity index of the power grid to be evaluated is determined.

[0030] Optionally, the calculating of the section operation safety margin index according to each section load rate includes:

[0031] For each of the operation control sections, calculating a section adjustment margin value based on the section load rate;

[0032] A summation calculation is performed based on each of the section adjustment margin values to obtain a section operation safety margin index of the power grid to be evaluated.

[0033] The present invention also provides a power grid planning and operation safety margin assessment device, comprising:

[0034] The optimization dispatching unit is used to optimize the dispatching of the power grid to be evaluated and obtain the optimal power grid dispatching result;

[0035] A load rate calculation unit, configured to calculate, based on the optimal grid dispatch result and mirror symmetry, the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section;

[0036] a safety operation index calculation unit, configured to calculate a component load uniformity index based on the load rate of each component, and to calculate a section operation safety margin index based on the load rate of each section;

[0037] A safety margin level assessment unit is used to assess the grid operation safety margin level of the grid to be assessed based on the component load uniformity index and the section operation safety margin index, and use the grid operation safety margin level as a scheme evaluation index when conducting grid planning for the grid to be assessed.

[0038] The present invention further provides an electronic device, comprising a processor and a memory:

[0039] The memory is used to store program code and transmit the program code to the processor;

[0040] The processor is used to execute the power grid planning operation safety margin assessment method as described in any one of the above items according to the instructions in the program code.

[0041] The present invention also provides a computer-readable storage medium, which is used to store program code, and the program code is used to execute the power grid planning and operation safety margin assessment method as described in any one of the above items.

[0042] It can be seen from the above technical solutions that the present invention has the following advantages:

[0043] A method for assessing the operational safety margin of power grid planning is proposed. First, the grid to be assessed is optimized to obtain the optimal grid dispatch result. Based on this optimized dispatch, a preliminary grid dispatch result under the optimal operating mode is obtained, which is used for subsequent assessment of the grid's operational safety margin level. Then, based on the optimal grid dispatch result, the component load factor of each component device and the section load factor of each operational control section in the grid to be assessed are calculated using mirror symmetry. This method considers both the component devices and the operational control sections, and proposes a more reasonable load factor calculation method based on mirror symmetry. Compared with existing load factor calculation methods, this method can better meet the calculation requirements of section load factors, scientifically evaluate the operational safety margin of sections, and improve system operational safety. Furthermore, the component load uniformity index is calculated based on the component load factor, and the section operational safety margin index is calculated based on the section load factor. Consequently, corresponding operational safety margin assessment methods are proposed for both component devices and operational control sections. These methods can better assess the load uniformity of all components in the system and the operational safety margin level of sections, thus improving the accuracy of operational safety margin assessment for power grid planning. Finally, based on the component load uniformity index and the section operation safety margin index, the grid operation safety margin level of the power grid to be evaluated can be accurately evaluated, which can be used as a scheme evaluation index when planning the power grid to be evaluated. Therefore, when multiple power grid planning schemes need to be selected to complete the power grid planning, the schemes can be evaluated and compared based on the grid operation safety margin levels of each power grid to select the appropriate power grid planning scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A flowchart of the steps of a method for evaluating the safety margin of power grid planning and operation;

[0046] Figure 2 A schematic diagram of iterative solution of Benders decomposition;

[0047] Figure 3 A mirror image diagram for calculating the load rate through mirror symmetry;

[0048] Figure 4 The figure is a schematic diagram of the overall process of a method for evaluating the safety margin of power grid planning and operation;

[0049] Figure 5 The present invention is a structural block diagram of a power grid planning and operation safety margin assessment device. DETAILED DESCRIPTION

[0050] The embodiments of the present invention provide a method, device, electronic device and medium for evaluating the safety margin of power grid planning and operation, which are used to solve or partially solve the technical problem that the current evaluation of the safety margin of power grid planning and operation is not comprehensive enough, thus failing to obtain the operating mode with the maximum power grid operation margin, resulting in inaccurate evaluation.

[0051] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0052] In order to enable those skilled in the art to better understand the technical solutions provided by the embodiments of the present invention, some of the technical features involved in the solutions are briefly described first:

[0053] Grid Operational Safety Margin: The power system's ability to meet current and future electricity demand while ensuring safe operation. This comprehensively considers the grid's stability and the adequacy of power supply, including its ability to cope with load fluctuations and equipment failures.

[0054] Operation Control Sections: Several power branches (equipment) selected by power grid system calculation and analysis personnel based on grid topology, operational experience, and safety constraints. Operation Control Sections are assigned corresponding section safety constraints. These constraints are calculated by section managers based on grid safety and stability standards and power supply reliability requirements. For example, the load power safety operation control lower and upper limits used in mirror symmetry calculations in this embodiment of the present invention are used.

[0055] As an example, current optimization scheduling mainly considers minimizing economic costs or maximizing social welfare, while also taking into account corresponding grid operational safety constraints. However, the actual scale of the grid is large, and the number of optimization variations is numerous. However, due to solution time constraints, only suboptimal solutions can be obtained within a certain convergence error or a set solution time threshold. In some special cases, the problem itself has multiple solutions, and commercial solvers can only obtain one valid solution among them. Although economic efficiency is guaranteed in this case, there may be multiple actual grid operation modes at the same economic level. Therefore, how to identify the operation mode with the maximum grid operation margin under various possible operation modes is also worthy of further research.

[0056] Furthermore, the present invention has found through analysis that although some related technologies have also considered the economy and safety of the power grid to construct a dual-objective optimization model, they only consider the ratio of the actual transmission capacity of the transmission element to its rated maximum transmission capacity to define the load rate, and do not consider that in the actual operation of the power grid, in addition to paying attention to the load rate of the component equipment itself, special attention should also be paid to the safety constraints corresponding to various power grid operation control sections.

[0057] Therefore, one of the core inventive aspects of the embodiments of the present invention is that, on the one hand, a scheduling optimization model that improves the operational safety margin of the power grid is constructed by comprehensively considering multiple relevant constraints and multi-objective optimization functions. The model is then transformed into a main problem and multiple sub-problems using the Benders decomposition algorithm for iterative solution. This model has high model solution efficiency, can be adapted to actual power grid applications, improve the system's safety and stability, and achieve an increase in the operational safety margin of the power grid. On the other hand, to fully consider the safety constraints of the power grid's operational control sections and further improve the operational safety margin of the power grid, a more reasonable load-rate-related index and calculation method for evaluating the operational safety margin of component equipment and sections is proposed. Compared with existing load-rate calculation methods, this method can better meet the calculation requirements of the section load rate, scientifically evaluate the operational safety margin of the section, and improve the safety of system operation. On this basis, corresponding operational safety margin evaluation index calculation methods are proposed for component equipment and operational control sections, which can better adapt to the evaluation of the load uniformity of all components in the system and the operational safety margin level of the section, thereby improving the accuracy of the operational safety margin assessment in power grid planning. Finally, the grid operation safety margin level obtained through the evaluation will be used as a scheme evaluation indicator when planning the power grid. Therefore, when multiple grid planning schemes need to be selected to complete the grid planning, the schemes can be evaluated and compared based on the grid operation safety margin levels of each grid to select the appropriate grid planning scheme.

[0058] Reference Figure 1 , shows a flowchart of a method for evaluating a safety margin of power grid planning operation provided by an embodiment of the present invention, which may specifically include the following steps:

[0059] Step 101, optimizing the grid to be evaluated to obtain the optimal grid scheduling result;

[0060] First, when optimizing the grid to be analyzed, it is necessary to consider the actual situation and the constraints related to grid operation. In the embodiment of the present invention, when optimizing the grid, the constraints such as conventional units, wind power, photovoltaic new energy, energy storage, component equipment rating limits, and grid operation control sections are mainly considered. At the same time, the Nk constraint formed by occasional situations such as line fault tripping that may easily occur in the actual operation of the grid is further considered.

[0061] In some embodiments, the process of optimizing the grid to be evaluated and obtaining the optimal grid scheduling result can be achieved by executing the following sub-steps S01 to S04:

[0062] Step S01: Constructing unit start-up and shutdown state association constraints, unit minimum start-up and shutdown time constraints, unit output range constraints, unit ramp rate constraints, line transmission capacity constraints, node phase angle constraints, node power balance constraints, wind power-photovoltaic output constraints, energy storage operation constraints, operation control section constraints, and line Nk constraints as multiple constraints for the power grid to be evaluated;

[0063] The constraints constructed in this step are as follows:

[0064] (1) Unit start-up and shutdown status association constraints

[0065]

[0066]

[0067] Where, Assemble for the generator set; is the time collection; To characterize the unit Time 0-1 variable for on / off status, 1 for on, 0 for off; It is a 0-1 variable that represents the startup of the unit. Time If the power is on, it is 1, otherwise it is 0; is a 0-1 variable representing the shutdown of the unit. Time If it is off, it is 1; otherwise, it is 0.

[0068] The above equation represents the relationship constraint between the start and stop states of the unit and the start and stop states. Furthermore, it is impossible for a unit to start and stop at the same time during the same period.

[0069] (2) Minimum start-up and shutdown time constraints of the unit

[0070]

[0071]

[0072] Where, 、 Respectively for units Minimum startup and shutdown time; 、 Respectively for units In the period Continuous startup and shutdown time variables.

[0073] (3) Unit output range constraints

[0074]

[0075] Where, 、 Generator sets Upper and lower limits of output; For the crew In the period The power output value.

[0076] (4) Unit ramp rate constraint

[0077]

[0078]

[0079] Where, 、 Respectively for units Upward and downward climbing rates; 、 Respectively for units The upward and downward climbing rates during start and stop.

[0080] (5) Line transmission capacity constraints

[0081]

[0082]

[0083] Where, is a collection of lines; For nodes In the period The phase angle; For the line reactance; For the line In the period The value of the transmitted active power; and Line Upper and lower limits of active transmission power; is an uncertain {0,1} variable that represents whether the line is faulty or not. If it is open, it is 0, and if it is closed, it is 1; It is a constant larger than the maximum line capacity in the system, mainly to ensure that the node phase angle constraint only works on lines without faults.

[0084] (6) Node phase angle constraint

[0085]

[0086] Where, is a collection of nodes; and Node The upper and lower limits of the phase angle.

[0087] (7) Node power balance constraints

[0088]

[0089] Where, Assemble for wind turbines; For photovoltaic units collection; Representation and Node connected wind farms; Representation and Node connected photovoltaic clusters; Representation and Node A collection of connected conventional generating units; Representation and Node A collection of connected energy storage; Representation and Node Connected and the end node is The set of lines; Representation and Node Connected and the starting node is The set of lines; For the period wind turbines contribution; For the period Photovoltaic units contribution; For nodes In the period load; Indicates the discharge power of energy storage; Indicates the charging power of energy storage; Indicates the amount of load loss at the node. It refers to the node A collection of connected loads.

[0090] (8) Wind power and photovoltaic output constraints

[0091]

[0092]

[0093] Where, , They are Moment wind turbines With photovoltaic units The maximum output value can be obtained by the short-term or ultra-short-term output forecast of wind power and photovoltaic power.

[0094] (9) Energy storage operation constraints

[0095] Conventional operation constraints related to energy storage include energy balance constraints, charge and discharge power constraints, energy constraints, initial and final state constraints, and charge and discharge logic constraints. They are shown in the following formulas:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] Where, A collection of energy storage devices; is the maximum charge and discharge power of the energy storage system; and are 0-1 variables representing the charging and discharging states of the energy storage system respectively; and are the charging and discharging efficiencies of the energy storage system, respectively; and are the upper and lower limits of the state of charge of the energy storage system respectively; is the initial state of charge of the energy storage system.

[0103] (10) Operation control section constraints

[0104]

[0105]

[0106] Where, Represents a cross section The relevant variables in the power grid involved may be the weighted sum of the coefficients of active power of multiple lines or the output of generator sets; and Section Upper and lower limits of For cross section Load factor; For cross section The corresponding upper limit of the operating control load rate. In actual operation, in order to cope with the normal fluctuation of new energy power, a certain section margin needs to be reserved. This is the reserved cross-sectional margin, typically ranging from 3% to 5%. In some special cases, a larger margin may be considered to cope with extreme operating scenarios, such as typhoons or extreme high temperatures.

[0107] (11) Line Nk constraint

[0108]

[0109] Where, The maximum number of lines that can be considered to have faults is 2 at most.

[0110] Step S02: constructing an optimization objective function for the power grid to be evaluated, with minimization of power grid operation costs, wind power curtailment penalty costs, solar power curtailment penalty costs, and load loss penalty costs as the optimization goal;

[0111] Under the various operating constraints considered above, the objective function optimized by the embodiment of the present invention is to minimize the operating cost of the power grid and the penalty costs such as wind power curtailment, solar power curtailment, and load loss. The corresponding optimization objective function is as follows:

[0112]

[0113] Where, 、 、 Respectively for units The coefficient term corresponding to the power generation cost function; and are the startup and shutdown costs of the unit respectively; represents the penalty cost coefficient for wind curtailment; represents the penalty cost coefficient for abandoned light; VOLL represents the penalty cost coefficient for loss of load.

[0114] Step S03: Constructing a scheduling optimization model based on the optimization objective function and multiple constraints;

[0115] Step S04: performing iterative optimization and solving on the dispatch optimization model to obtain the optimal grid dispatch result of the grid to be evaluated.

[0116] Specifically, the dispatch optimization model is iteratively optimized and solved to obtain the grid dispatch result under the optimal dispatch condition, which is used as the optimal grid dispatch result of the grid to be evaluated.

[0117] Furthermore, the scheduling optimization model is iteratively optimized and solved to obtain the power grid scheduling result under the optimal scheduling condition. Specifically, the scheduling optimization model is divided into a main problem and a series of sub-problems based on Benders decomposition, and the main problem and a series of sub-problems are repeatedly iteratively solved until the preset convergence conditions are met (such as reaching a preset number of iterations, or the difference between the upper bound and the lower bound is small enough), and the power grid scheduling result under the optimal scheduling condition is obtained.

[0118] Specifically, since all constraints in the above-mentioned scheduling optimization model are linear, it is a mixed integer linear programming problem. Although existing mature commercial solvers can be used for solving, if the system is large or the optimization scheduling cycle is long, it may face the problems of long calculation time and low calculation efficiency. Therefore, the embodiment of the present invention further provides a method based on Benders decomposition to divide the proposed scheduling optimization model into a main problem and a series of sub-problems for iterative solution. The schematic diagram of the iterative solution of Benders decomposition is shown in FIG. Figure 2 shown.

[0119] The specific formula related to Benders decomposition is as follows:

[0120]

[0121] Where, Variables that represent the correlation between 0-1 variables in the scheduling optimization model; Variables used to characterize the correlation between continuous variables in scheduling optimization models; 、 is the coefficient of the constraint; is the limit coefficient corresponding to the constraint; 、 is the correlation coefficient in the objective function.

[0122] When fixed 0-1 variable After that, we can get a suboptimal solution to the original problem, that is, the upper limit of the objective function of the original problem. Further using the duality principle, we can get the subproblem corresponding to the Benders decomposition method as follows:

[0123]

[0124] Where, is the introduced dual variable.

[0125] After solving the sub-problem, add constraints to the main problem according to the judgment results to solve it, and you can get a new 0-1 variable again. . Repeated iterative solution until convergence. The corresponding form of the main problem is:

[0126]

[0127] Where, Auxiliary variables for the objective function of the introduced sub-problem; is the dual variable corresponding to the constraints of the original problem; Here, represents the number of iterations.

[0128] It's understandable that the master problem is actually a relaxation of the original problem. The objective function of the master problem is calculated to be better than that of the original problem, thus serving as a lower bound for the original problem's objective function. As iterations proceed, the iterations stop when the difference between the upper and lower bounds is sufficiently small.

[0129] Step 102, based on the optimal grid dispatch result, respectively calculating the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section based on mirror symmetry;

[0130] In an embodiment of the present invention, by comprehensively considering the load conditions of component equipment (mainly lines, transformers, etc.) in the power grid to be evaluated and the load conditions of the power grid operation control section, a load rate calculation method suitable for evaluating the power grid operation safety margin is first proposed based on mirror symmetry to reasonably characterize the load rates of lines, transformers and sections.

[0131] It should be noted that for normal circuits, transformers, and other components, the upper and lower operating safety limits are often the limits for forward and reverse rated operation. This means that the upper and lower limits for safe operation are opposite to each other. However, for safety control sections, the upper and lower limits are not necessarily symmetrical, and thus, they are not necessarily opposite to each other. Therefore, a reasonable and scientific load factor calculation method is needed to accommodate such safety control constraints.

[0132] In a specific implementation, the optimal grid dispatch result may include a first actual load power value for each component device in the grid to be evaluated and a second actual load power value for each operation control section. The first actual load power value and the second actual load power value can both be understood as actual power flow values obtained through actual optimization scheduling calculations. To distinguish the actual power flow values of the component devices from those of the operation control sections, the first actual load power value represents the actual load power value of the component devices, and the second actual load power value represents the actual load power value of the operation control section.

[0133] In some embodiments, according to the optimal grid dispatching results, the component load rate of each component equipment in the grid to be evaluated and the section load rate of each operation control section are calculated based on mirror symmetry. Specifically, it can be as follows: for each component equipment, a mirror symmetric calculation is performed based on the first actual load power value, the first preset load power lower limit value and the first preset load power upper limit value to obtain the component load rate of the component equipment; for each operation control section, a mirror symmetric calculation is performed based on the second actual load power value, the second preset load power lower limit value and the second preset load power upper limit value to obtain the section load rate of the operation control section.

[0134] For example, Figure 3 A mirror diagram for calculating the load factor by mirror symmetry is shown.

[0135] Figure 3 middle, Indicates the target load that needs to be solved; Indicates the actual power flow value (i.e. actual load power value) of the component equipment or operation control section; Indicates the load power safety operation control lower limit value (i.e. load power lower limit value) of the component equipment or operation control section. Indicates the upper limit of load power safety operation control (i.e. load power upper limit) of the component equipment or operation control section.

[0136] Combine Figure 3 The process of performing mirror symmetry calculation on component equipment to obtain component load rate, or performing mirror symmetry calculation on operation control section to obtain section load rate can be as follows: first, for the target load rate to be calculated (When performing mirror symmetry calculation for component equipment, the target load rate corresponds to the component load rate. When performing mirror symmetry calculation for the operation control section, the target load rate corresponds to the section load rate. The load power value, load power lower limit value and load power upper limit value and other parameters described below also have the same corresponding relationship as described above during calculation, which will not be repeated here.) Any target actual load power value , for the target actual load power value The corresponding target preset load power lower limit and target preset load power upper limit Perform numerical judgment (specifically, determine whether the value is positive or negative).

[0137] when hour:

[0138] like ,but .

[0139] like ,but .

[0140] when hour:

[0141] like ,but .

[0142] like ,but .

[0143] when and hour:

[0144] like ,but .

[0145] like ,but .

[0146] The load factor calculation method provided by the embodiments of the present invention demonstrates the scientific validity of the load factor when the actual power flow value is near the upper and lower limits of safe operation control. In this case, the corresponding load factor is close to 1, and the operating margin is small. This effectively meets the need for evaluating the safety margin of power grid operation.

[0147] Step 103, calculating a component load uniformity index based on the component load rate, and calculating a section operation safety margin index based on the section load rate;

[0148] Based on the load rate calculation method proposed in the previous step, the corresponding operation safety margin indicators are further calculated based on the different types of load rates solved.

[0149] In some embodiments, the process of calculating the component load uniformity index according to the load rate of each component can be achieved by executing the following sub-steps S11 to S13:

[0150] Step S11: Calculating the average load rate of each component by using the mean value method according to the load rate of each component;

[0151] Take the component equipment as a circuit as an example. Assume that the load rate of the circuit is For the line, the average load rate of the line in the entire system is:

[0152]

[0153] Where, It represents the average value of the line load rate in the entire system (corresponding to the power grid to be evaluated); Indicates the total number of lines in the system.

[0154] Step S12: Calculating the standard deviation based on the average component load rate and the load rates of each component to obtain a component load rate difference value;

[0155] Furthermore, the standard deviation is used to measure the degree of difference between the line load rates in the system. Specifically, the line load rate difference value is calculated by the following formula:

[0156]

[0157] Step S13: determining a component load uniformity index of the power grid to be evaluated based on the component load rate difference degree value.

[0158] Will As an indicator to evaluate the load uniformity of all lines in the system.

[0159] Due to the line load exist between, so The value range is also And at the same load level, The smaller it is, the more uniform the load rates among the lines in the system are, the larger the corresponding adjustment space for line flow operation is, and the higher the safety margin of system operation is.

[0160] However, for operational control sections, the load factor calculation results may differ significantly from those for the line. This is because, based on the aforementioned mirror-symmetric load factor calculation principle, the numerical values for different section types may vary significantly. Furthermore, the minimum load factors corresponding to the upper and lower thresholds for different sections may also vary significantly. Therefore, the aforementioned line uniformity index cannot be used to evaluate the operational margin level of the section. However, the mirror-symmetric section load factor calculation method proposed in this invention can more scientifically assess the load factor level near the section's operational boundary.

[0161] In some embodiments, the process of calculating the section operation safety margin index according to each section load rate can be achieved by executing the following sub-steps S21 to S22:

[0162] Step S21: for each operation control section, calculating the section adjustment margin value based on the section load rate;

[0163] Assume that the load rate corresponding to the operating control section is , calculate the section adjustment margin value by the following formula:

[0164]

[0165] Step S22: performing summation calculation based on the adjustment margin values of each section to obtain the section operation safety margin index of the power grid to be evaluated.

[0166]

[0167] Where, Represents the set of operating control sections in the system; It represents the sum of the section safety margins in the entire system, corresponding to the section safety margin index of the power grid to be evaluated.

[0168] As the system moves closer to the control boundary of the section, The closer it is to 1, the larger the cross-section adjustment margin value. The smaller the value, the smaller the corresponding cross-section adjustment space, and therefore the smaller the operating safety margin level.

[0169] Step 104 : Based on the component load uniformity index and the section operation safety margin index, the grid operation safety margin level of the grid to be evaluated is evaluated, and the grid operation safety margin level is used as a scheme evaluation index when performing grid planning for the grid to be evaluated.

[0170] Through the above lines and operation control sections corresponding and The comparison of the two indicators can effectively evaluate the safety margin of system operation and measure the margin under different operating modes.

[0171] Furthermore, the grid operation safety margin level can be used as a scheme evaluation indicator when conducting grid planning for the grid to be evaluated. Therefore, when it is necessary to select an appropriate scheme from multiple grid planning schemes, those skilled in the art can evaluate the corresponding grid planning schemes based on the grid operation safety margin level according to actual needs, select the most appropriate scheme, and complete the grid planning.

[0172] In an embodiment of the present invention, a scheduling optimization model for improving the operational safety margin of a power grid is constructed by comprehensively considering multiple relevant constraints and multi-objective optimization functions. The model is then transformed into a main problem and multiple sub-problems using the Benders decomposition algorithm for iterative solution. This model has high computational efficiency, is adaptable to actual power grid applications, improves the system's safety and stability, and achieves an increase in the operational safety margin of the power grid. Furthermore, to fully consider the safety constraints of power grid operational control sections and further improve the operational safety margin of the power grid, a more reasonable load-rate-related index and calculation method for evaluating the operational safety margin of component equipment and sections is proposed. Compared with existing load-rate calculation methods, this method can better meet the calculation requirements of section load rates, scientifically evaluate the operational safety margin of sections, and improve the safety of system operation. Furthermore, corresponding operational safety margin evaluation index calculation methods are proposed for component equipment and operational control sections, respectively. These methods can better adapt to the evaluation of the load uniformity of all components in the system and the operational safety margin level of sections, thereby improving the accuracy of operational safety margin assessment in power grid planning. Finally, the grid operation safety margin level obtained through the evaluation will be used as a scheme evaluation indicator when planning the power grid. Therefore, when multiple grid planning schemes need to be selected to complete the grid planning, the schemes can be evaluated and compared based on the grid operation safety margin levels of each grid to select the appropriate grid planning scheme.

[0173] For better explanation, refer to Figure 4 , which shows a schematic diagram of the overall process of a method for evaluating the safety margin of power grid planning and operation provided by an embodiment of the present invention. It should be noted that this embodiment only briefly describes the general process of evaluating the safety margin of power grid planning and operation. The specific implementation process of each step can be understood by referring to the relevant content in the aforementioned embodiments. It will not be described here in detail. It is understood that the present invention is not limited to this.

[0174] Step 401: constructing multiple constraints and a multi-objective optimization function for the power grid to be evaluated, and constructing a scheduling optimization model based on the multiple constraints and the multi-objective optimization function;

[0175] Step 402: performing iterative optimization and solving of the dispatch optimization model based on Benders decomposition to obtain a grid dispatch result under the optimal dispatch condition as the optimal grid dispatch result of the grid to be evaluated;

[0176] Step 403: Calculate the line load rate of each line in the power grid to be evaluated and the section load rate of each operation control section based on mirror symmetry according to the optimal power grid dispatch result;

[0177] Step 404: Calculate the line load uniformity index based on the load rate of each line, and calculate the section operation safety margin index based on the load rate of each section;

[0178] Step 405: Based on the line load uniformity index and the section operation safety margin index, the grid operation safety margin level of the grid to be evaluated is evaluated as a scheme evaluation index when performing grid planning for the grid to be evaluated.

[0179] Reference Figure 5 , shows a structural block diagram of a power grid planning and operation safety margin assessment device provided by an embodiment of the present invention, which may specifically include:

[0180] The optimization and scheduling unit 501 is used to optimize the scheduling of the power grid to be evaluated and obtain the optimal power grid scheduling result;

[0181] A load rate calculation unit 502 is configured to calculate, based on the optimal grid dispatch result and mirror symmetry, the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section;

[0182] A safety operation index calculation unit 503 is used to calculate the component load uniformity index according to the load rate of each component, and calculate the section operation safety margin index according to the load rate of each section;

[0183] The safety margin level evaluation unit 504 is used to evaluate the grid operation safety margin level of the grid to be evaluated based on the component load uniformity index and the section operation safety margin index, and use the grid operation safety margin level as a scheme evaluation index when performing grid planning for the grid to be evaluated.

[0184] In an optional embodiment, the optimization scheduling unit 501 includes:

[0185] A multi-constraint construction unit is used to construct unit start-up and shutdown state association constraints, unit minimum start-up and shutdown time constraints, unit output range constraints, unit ramp rate constraints, line transmission capacity constraints, node phase angle constraints, node power balance constraints, wind power-photovoltaic output constraints, energy storage operation constraints, operation control section constraints and line Nk constraints as multi-constraint conditions of the power grid to be evaluated;

[0186] An optimization objective function construction unit is used to construct an optimization objective function of the power grid to be evaluated with minimization of power grid operation cost, wind abandonment penalty cost, solar abandonment penalty cost and load loss penalty cost as the optimization goal;

[0187] A scheduling optimization model construction unit, configured to construct a scheduling optimization model according to the optimization objective function and the multiple constraints;

[0188] The optimization solution unit is used to iteratively optimize and solve the scheduling optimization model to obtain the optimal grid scheduling result of the grid to be evaluated.

[0189] In an optional embodiment, the optimization solution unit is specifically configured to:

[0190] The scheduling optimization model is divided into a main problem and a series of sub-problems based on Benders decomposition, and the main problem and a series of sub-problems are repeatedly iteratively solved until the preset convergence conditions are met, thereby obtaining the power grid scheduling result under the optimal scheduling condition.

[0191] In an optional embodiment, the optimal grid dispatch result includes a first actual load power value of each component device in the grid to be evaluated and a second actual load power value of each operation control section; the load rate calculation unit 502 includes:

[0192] a component load rate calculation subunit, configured to perform a mirror-symmetric calculation on each component device according to the first actual load power value, the first preset load power lower limit value, and the first preset load power upper limit value to obtain the component load rate of the component device;

[0193] The section load rate calculation subunit is used to perform mirror-symmetric calculation on each of the operation control sections according to the second actual load power value, the second preset load power lower limit value and the second preset load power upper limit value to obtain the section load rate of the operation control section.

[0194] In an optional embodiment, the process of performing the mirror symmetry calculation in the component load rate calculation subunit or the section load rate calculation subunit includes:

[0195] For the target load factor Any target actual load power value , the target actual load power value The corresponding target preset load power lower limit and target preset load power upper limit Make numerical judgments;

[0196] when When: If ,but ;like ,but ;

[0197] when When: If ,but ;like ,but ;

[0198] when and When: If ,but ;like ,but .

[0199] In an optional embodiment, the safety operation index calculation unit 503 includes:

[0200] an element average load rate calculation subunit, configured to calculate the element average load rate by a mean value method based on the load rates of the respective elements;

[0201] a component load rate difference degree value calculation subunit, configured to calculate a standard deviation based on the component average load rate and the load rates of each component to obtain a component load rate difference degree value;

[0202] The component load uniformity index calculation subunit is used to determine the component load uniformity index of the power grid to be evaluated based on the component load rate difference degree value.

[0203] In an optional embodiment, the safety operation index calculation unit 503 includes:

[0204] a section adjustment margin value calculation subunit, configured to calculate a section adjustment margin value based on the section load rate for each of the operation control sections;

[0205] The section operation safety margin index calculation subunit is used to perform summation calculation based on each of the section adjustment margin values to obtain the section operation safety margin index of the power grid to be evaluated.

[0206] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the aforementioned method embodiment.

[0207] It should be noted that, in order to enable those skilled in the art to better distinguish data of the same type but with different actual meanings, some technical features are distinguished by the first and second in the embodiments of the present invention. The first and second are only used for data distinction and have no other special meanings. It can be understood that the present invention does not impose any restrictions on this.

[0208] An embodiment of the present invention further provides an electronic device, the device including a processor and a memory:

[0209] The memory is used to store program codes and transmit the program codes to the processor;

[0210] The processor is used to execute the power grid planning and operation safety margin assessment method of any embodiment of the present invention according to the instructions in the program code.

[0211] An embodiment of the present invention further provides a computer-readable storage medium, which is used to store program code, and the program code is used to execute the power grid planning and operation safety margin assessment method of any embodiment of the present invention.

[0212] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0213] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0214] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0215] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0216] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0217] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the safety margin of power grid planning and operation, characterized in that: include: Optimize the dispatch of the power grid to be evaluated and obtain the optimal grid dispatch result; According to the optimal grid dispatch result, the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section are calculated based on mirror symmetry; Calculating the component load uniformity index based on the component load rate, and calculating the section operation safety margin index based on the section load rate; Based on the component load uniformity index and the section operation safety margin index, the grid operation safety margin level of the grid to be evaluated is evaluated, and the grid operation safety margin level is used as a scheme evaluation index when performing grid planning for the grid to be evaluated.

2. The method for evaluating the safety margin of power grid planning and operation according to claim 1, characterized in that: The optimizing and dispatching of the power grid to be evaluated to obtain the optimal power grid dispatching result includes: Constructing unit start-up and shutdown state association constraints, unit minimum start-up and shutdown time constraints, unit output range constraints, unit ramp rate constraints, line transmission capacity constraints, node phase angle constraints, node power balance constraints, wind power-photovoltaic output constraints, energy storage operation constraints, operation control section constraints and line Nk constraints as multiple constraints of the power grid to be evaluated; Taking minimizing the grid operation cost, wind curtailment penalty cost, solar curtailment penalty cost and load loss penalty cost as the optimization goal, an optimization objective function of the grid to be evaluated is constructed; Constructing a scheduling optimization model according to the optimization objective function and the multiple constraints; The dispatch optimization model is iteratively optimized and solved to obtain the optimal grid dispatch result of the grid to be evaluated.

3. The method for evaluating the safety margin of power grid planning and operation according to claim 2, characterized in that: The iterative optimization and solving of the dispatch optimization model to obtain the optimal grid dispatch result of the grid to be evaluated includes: The scheduling optimization model is divided into a main problem and a series of sub-problems based on Benders decomposition, and the main problem and a series of sub-problems are repeatedly iteratively solved until the preset convergence conditions are met, thereby obtaining the power grid scheduling result under the optimal scheduling condition.

4. The method for evaluating the safety margin of power grid planning and operation according to claim 2, wherein: The optimal grid dispatching result includes a first actual load power value of each component device in the grid to be evaluated and a second actual load power value of each operation control section; The calculating of the component load rate of each component device in the power grid to be evaluated and the section load rate of each operation control section based on the mirror symmetry according to the optimal power grid dispatch result includes: For each of the component devices, performing a mirror-symmetric calculation according to the first actual load power value, the first preset load power lower limit value, and the first preset load power upper limit value to obtain a component load rate of the component device; For each of the operation control sections, a mirror-symmetric calculation is performed according to the second actual load power value, the second preset load power lower limit value, and the second preset load power upper limit value to obtain the section load rate of the operation control section.

5. The method for evaluating the safety margin of power grid planning and operation according to claim 4, characterized in that: The process of performing a mirror symmetric calculation on the component equipment to obtain the component load rate, or performing a mirror symmetric calculation on the operation control section to obtain the section load rate, includes: For the target load factor Any target actual load power value , the target actual load power value The corresponding target preset load power lower limit and target preset load power upper limit Make numerical judgments; when When: If ,but ;like ,but ; when When: If ,but ;like ,but ; when and When: If ,but ;like ,but .

6. The method for evaluating the safety margin of power grid planning and operation according to any one of claims 1 to 5, characterized in that: Calculating the component load uniformity index according to the component load rate includes: Calculating the average load rate of the components by using the mean value method according to the load rates of the components; Calculate the standard deviation of the component load rate and each component load rate to obtain a component load rate difference value; Based on the component load rate difference degree value, a component load uniformity index of the power grid to be evaluated is determined.

7. The method for evaluating the safety margin of power grid planning and operation according to any one of claims 1 to 5, characterized in that: Calculating the section operation safety margin index according to each section load rate includes: For each of the operation control sections, calculating a section adjustment margin value based on the section load rate; A summation calculation is performed based on each of the section adjustment margin values to obtain a section operation safety margin index of the power grid to be evaluated.

8. A power grid planning and operation safety margin assessment device, characterized in that: include: The optimization dispatching unit is used to optimize the dispatching of the power grid to be evaluated and obtain the optimal power grid dispatching result; A load rate calculation unit, configured to calculate, based on the optimal grid dispatch result and mirror symmetry, the component load rate of each component device in the grid to be evaluated and the section load rate of each operation control section; a safety operation index calculation unit, configured to calculate a component load uniformity index based on the load rate of each component, and to calculate a section operation safety margin index based on the load rate of each section; A safety margin level assessment unit is used to assess the grid operation safety margin level of the grid to be assessed based on the component load uniformity index and the section operation safety margin index, and use the grid operation safety margin level as a scheme evaluation index when conducting grid planning for the grid to be assessed.

9. An electronic device, characterized in that: The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the power grid planning and operation safety margin assessment method according to any one of claims 1 to 7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store program code, and the program code is used to execute the power grid planning and operation safety margin assessment method according to any one of claims 1 to 7.

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