Regional output limit regulation and control method, device and equipment

Abstract

The invention discloses a regional output limit regulation and control method, device and equipment. The method comprises the following steps: acquiring the number of units and the number of output modes of various units in a target region; determining an initial number of output combinations corresponding to the target area according to the number of units and the number of output modes; if the initial number of the output combinations exceeds the calculation threshold value, the output mode number is reduced according to the unit capacity of the unit, and multiple unit output combinations are determined; performing load flow calculation on the target area according to each unit output combination, determining a target unit output combination in a load flow convergence state, performing transient simulation, and determining a stability control result of each target unit output combination; and according to each stability control result, determining an output limit corresponding to the target area and performing regulation and control. Therefore, the unit capacity reduction is combined with the load flow calculation and the transient simulation, the unit output combination is effectively and quickly screened, the precise quantification of the output capacity is further realized, and a precise setting value is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of output regulation, and in particular to a method, device and equipment for regulating regional output limits. Background Art

[0002] The safe and stable operation of power systems is a core guarantee of energy supply. Systems must always maintain stability under any single fault. However, in actual operation, systems often experience failures due to unexpected factors. This requires stable control technologies to respond promptly to incidents and maintain system stability. The three-line defense mechanism is currently the mainstream framework for achieving stable control in power grids. This framework, through a layered defense approach, provides response strategies for faults of varying severity and is a fundamental system for ensuring the security of large power grids.

[0003] Of the three lines of defense, the second primarily initiates responses to severe faults. Its core goal is to minimize the amount of action required while ensuring system stability through precise parameter settings, thereby minimizing the impact of any incidents. In large AC / DC hybrid power grids, power sources and loads exhibit significant clustered distribution characteristics. Practice has shown that controlling power at critical sections is crucial for ensuring system stability. However, due to complex factors such as spinning reserve and power flow distribution, setting parameters solely based on section power can easily lead to two types of problems: setting values ​​too high can cause a failure to prevent damage, while setting values ​​too low can lead to overly sensitive operations and unnecessary losses.

[0004] As can be seen, existing technologies rely heavily on the empirical judgment of computer operators when determining the transmission capacity boundaries of concentrated power transmission areas. To ensure safety, a large margin is often required. This not only reduces the economic efficiency of grid operation but also makes it difficult to accommodate certain special operating modes. This empirical approach has obvious limitations. It cannot accurately quantify transmission capacity and is difficult to adapt to the increasingly complex operating scenarios of large AC / DC hybrid power grids. Summary of the Invention

[0005] The present invention provides a method, device and equipment for regional output limit control, which solves the technical problems that the traditional experience-based approach has obvious limitations, cannot achieve accurate quantification of transmission capacity, and is difficult to adapt to the increasingly complex operating scenarios of large AC / DC hybrid power grids.

[0006] A first aspect of the present invention provides a method for controlling regional output limits, comprising:

[0007] Obtain the number of units and output modes of each type of unit in the target area;

[0008] Determining an initial number of output combinations corresponding to the target area according to the number of units and the number of output modes;

[0009] If the initial number of the output combinations exceeds the calculation threshold, the number of the output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations;

[0010] Performing power flow calculations on the target area according to each of the unit output combinations, determining the target unit output combination under the power flow convergence state, and performing transient simulation to determine the stability control results of each of the target unit output combinations;

[0011] According to the stabilization control results, the output limit corresponding to the target area is determined and regulated.

[0012] Optionally, determining the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes includes:

[0013] Performing power operations on the number of output modes according to the number of each unit to obtain the number of output mode combinations corresponding to each unit;

[0014] The multiplication value between the output mode combination numbers is calculated to obtain the initial number of output combinations corresponding to the target area.

[0015] Optionally, if the initial number of the output combinations exceeds a calculation threshold, the number of the output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations, including:

[0016] If the initial number of output combinations exceeds the calculation threshold, the priority of each unit is calculated according to the unit capacity and the corresponding number of output modes of each unit; the unit is also provided with an importance identifier;

[0017] If there is a unit with the importance mark as non-key, the number of output modes of the unit with the lowest priority and belonging to non-key is reduced according to the preset reduction gradient to obtain a new number of output modes;

[0018] If there is only a unit with the importance mark as the priority, the number of output modes of the unit with the lowest priority is reduced according to the preset reduction gradient to obtain a new number of output modes;

[0019] Jumping to the step of determining the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes, until the initial number of output combinations is lower than the calculation threshold, thereby obtaining a plurality of initial unit output combinations;

[0020] The initial unit output combinations are screened to obtain multiple unit output combinations.

[0021] Optionally, the initial unit output combinations are screened to obtain multiple unit output combinations, including:

[0022] Sort the initial unit output combinations from high to low according to the total output upper limit to obtain a unit output combination sequence;

[0023] The unit output combination sequence is divided by using a partition method to obtain multiple optimized unit output combinations;

[0024] The optimized unit output combinations that are below the historical output lower limit are screened out to obtain a variety of unit output combinations.

[0025] Optionally, performing power flow calculation for each of the unit output combinations for the target area, determining a target unit output combination under a power flow convergence state and performing transient simulation, and determining a stabilization control result for each target unit output combination according to the simulation result, includes:

[0026] Acquiring power grid topology data corresponding to the target area;

[0027] Traversing the unit output combinations, and building a power flow calculation model according to the unit output combinations and the power grid topology data;

[0028] Iteratively solving the power flow calculation model using a preset power flow algorithm to obtain a power flow calculation result;

[0029] If the power flow calculation result has not converged, adjusting the unit outputs within the target unit output combination according to the power flow calculation result and a preset adjustment gradient to update the unit output combination;

[0030] Jump to the step of constructing a power flow calculation model according to the unit output combination and the grid topology data until the power flow calculation result converges and a target unit output combination in a power flow convergence state is obtained;

[0031] The target unit output combinations are used to perform transient simulation, and the stabilization control results of the target unit output combinations are determined according to the simulation results.

[0032] Optionally, the performing transient simulation using the target unit output combination to determine the stabilization control result of each target unit output combination includes:

[0033] Using each target unit output combination to construct a transient simulation topology model;

[0034] The preset transient simulation software is used to simulate each of the transient simulation topology models according to the preset fault type to obtain a stabilization result.

[0035] Optionally, determining the output limit corresponding to the target area and performing regulation according to each of the stabilization control results includes:

[0036] Selecting a target action result that is stable after the stabilization action from each of the stabilization control results;

[0037] According to the target unit output combination associated with the target action result, the total output under different numbers of units is selected and rounded to obtain the output limit corresponding to the target area;

[0038] The operation control requirements or output setting values ​​corresponding to the target area are adjusted according to the output limit.

[0039] Optionally, the method further includes:

[0040] If the initial number of output combinations does not exceed the calculation threshold, then obtaining all unit output combinations corresponding to the initial number of output combinations;

[0041] Jump to the step of performing power flow calculation according to each of the unit output combinations, determining the target unit output combination under the power flow convergence state and performing transient simulation, and determining the stabilization control result of each target unit output combination according to the simulation result.

[0042] The second aspect of the present invention further provides a regional output limit control device, comprising:

[0043] The quantity acquisition module is used to obtain the number of units and output modes of each type of unit in the target area;

[0044] an output combination initial number determination module, configured to determine the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes;

[0045] an output mode reduction module, configured to reduce the number of output modes according to the unit capacity of the unit if the initial number of the output combinations exceeds a calculation threshold, and determine multiple unit output combinations;

[0046] a stabilization control result determination module, configured to perform power flow calculations for the target area according to each of the power unit output combinations, determine the target power unit output combination under the power flow convergence state, perform transient simulation, and determine the stabilization control results for each of the target power unit output combinations;

[0047] The stabilization control adjustment module is used to determine the output limit corresponding to the target area and perform regulation according to each of the stabilization control results.

[0048] The third aspect of the present invention also provides an electronic device, characterized in that it includes a memory and a processor, and a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the regional output limit control method as described in any one of the first aspects of the present invention.

[0049] It can be seen from the above technical solutions that the present invention has the following advantages:

[0050] The present invention obtains the number of units and the number of output modes of each type of unit in the target area; determines the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes; if the initial number of output combinations exceeds the calculation threshold, the number of output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations; performs flow calculations on the target area according to each unit output combination, determines the target unit output combination under the flow convergence state and performs transient simulation to determine the stability control results of each target unit output combination; determines the output limit corresponding to the target area and performs regulation according to each stability control result. Thus, by combining the unit capacity reduction with the flow calculation and transient simulation, the unit output combination can be effectively and quickly screened, thereby achieving accurate quantification of the delivery capacity and providing accurate set values. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] 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.

[0052] Figure 1 A flowchart of the steps of a method for controlling regional output limits provided by an embodiment of the present invention;

[0053] Figure 2 This is a structural block diagram of a regional output limit control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] As power grids evolve into large, hybrid AC / DC systems, the clustered distribution of power sources and loads has become more prominent. This clustered distribution offers advantages such as lower transmission costs and easier control, but it also carries a greater impact on the grid in the event of a fault. Therefore, in-depth analysis of these characteristics can effectively improve grid security and efficiency. Since the region itself is a concentrated power or load transmission area, this has little impact on the following analysis. Therefore, the subsequent analysis focuses on areas with concentrated power transmission.

[0055] Because power sources are distributed in clusters, the interconnecting sections formed by the interconnecting lines between them and the grid are crucial for implementing control. High section power indicates high power generation. If a tie-line trip occurs at this point, the impact on the grid will be significant, potentially endangering its safety. Existing technologies generally employ two methods for implementing control: pre-control of sections, which ensures stability by limiting section power to a specified value. The other utilizes a stabilizing control device with a pre-set value. When the section power exceeds this value and a tripping fault occurs, the unit is disconnected. As can be seen, both control modes require a clear definition of the section power level at which the system will become unstable after a fault.

[0056] However, the potential for power supply startup modes is so numerous that it's difficult to account for all possibilities. In the past, addressing this issue often relied on the experience of computer operators: verifying the stability of typical modes and assigning appropriate margins. However, actual operational experience has shown that under certain startup modes, even if the cross-sectional power meets the requirements, instability can still occur after a fault. Ultimately, the existing approach still relies on an estimate of the output limit of the power supply's transmission area. Further increasing the margin, while ensuring safety, would significantly reduce the economic efficiency of system operation.

[0057] The embodiments of the present invention provide a method, device and equipment for regional output limit control, which are used to solve the technical problems that the traditional experience-based approach has obvious limitations, cannot achieve accurate quantification of transmission capacity, and is difficult to adapt to the increasingly complex operating scenarios of large AC / DC hybrid power grids.

[0058] 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.

[0059] See also Figure 1 , Figure 1 A flowchart of the steps of a regional output limit control method provided by an embodiment of the present invention.

[0060] The present invention provides a method for controlling regional output limits, comprising:

[0061] Step 101, obtaining the number of units and the number of output modes of each type of units in the target area;

[0062] The target area refers to a specific geographical or electrical area to be regulated in the power system, such as a city power supply area, a power grid zone, etc. It is the scope definition for carrying out unit output-related analysis and calculations.

[0063] The types of units include but are not limited to thermal power units, hydropower units and new energy units.

[0064] The number of units refers to the actual number of units of the corresponding category in the target area, which is used to quantify the scale of units of this category.

[0065] The number of output modes refers to the number of different output states in which each type of unit can operate. For example, a thermal power unit can operate at rated output, 75% rated output, and 50% rated output, reflecting the unit's output adjustment capabilities.

[0066] In an embodiment of the present application, a survey of the power system within the target area can be conducted to clearly classify the units based on energy type, unit characteristics, etc., such as thermal power units (further distinguishing between coal-fired and gas-fired units), hydropower units (conventional hydropower, pumped storage), and new energy units (wind power, photovoltaic). At the same time, the actual number of units of each type can be counted through channels such as the power grid dispatching system and power plant equipment records, thereby obtaining the number of units and the number of output modes for each type of unit. For example, there are 2 thermal power units and 3 hydropower units in a certain area. The output of the thermal power units is 600, 800, and 1000, and the output of the hydropower units is 300, 400, 500, and 600.

[0067] Step 102: Determine the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes;

[0068] The initial number of output combinations refers to the total number of all possible unit output combinations.

[0069] In an embodiment of the present application, for each type of unit, the possible number of output mode combinations is the number of units of the unit's output mode number raised to the power of the number of units. By calculating the multiplication value between the output mode combination numbers of each unit, the initial number of output combinations corresponding to the target area is obtained.

[0070] In one example of the present application, step 102 may include the following sub-steps:

[0071] Perform power operations on the number of output modes according to the number of units to obtain the number of output mode combinations corresponding to each unit;

[0072] Calculate the multiplication value between the number of output mode combinations to obtain the initial number of output combinations corresponding to the target area.

[0073] In this embodiment, for each type of unit in the target area, the number of output mode combinations corresponding to that type of unit is determined by exponential operation based on the number of units in that type and the number of output modes. Assuming that the number of units in a certain type is n (i.e., the unit type includes n independent units), and the number of output modes of that type of unit is m (each unit can select an output gear, including 0% output, i.e., shutdown state), the number of output mode combinations of that type of unit is m. n .

[0074] After calculating the number of output mode combinations for each type of unit, multiply each output mode combination by its value to obtain the initial number of output combinations corresponding to the target area. For example, based on the above example, the number of possible combinations is 4^2*5^3=2000. A single thermal power unit and hydropower unit has 4 or 5 output modes, respectively. Note that an output of 0 (i.e., shutdown) is also possible.

[0075] Step 103: If the initial number of output combinations exceeds the calculated threshold, the number of output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations;

[0076] The calculation threshold refers to a pre-set critical value used to determine whether the initial number of output combinations is too large and whether combination optimization is needed. It can be set based on computing resources such as computer computing power, memory, analysis time limit, etc., for example, it can be set to 100,000.

[0077] In an embodiment of the present application, if the initial number of output combinations exceeds the calculation threshold, in order to prevent the calculation efficiency of subsequent calculations, the number of possible output modes can be reduced according to the unit capacity of each unit to screen the initial number of output combinations and obtain a plurality of unit output combinations whose number is less than the calculation threshold.

[0078] In an example of the present application, step 103 may include the following sub-steps S11-S15:

[0079] S11. If the initial number of output combinations exceeds the calculation threshold, the priority of each group is calculated according to the capacity of each group and the number of corresponding output modes; the group is also provided with an importance indicator;

[0080] In the embodiment of the present application, if the initial number of output combinations exceeds the calculation threshold, it indicates that the number of output combinations is too large and is not suitable for the calculation of the current computing device. At the same time, since the initial number of output combinations includes all possible output combinations, some output combinations may not be used in actual operation. Therefore, for each unit output combination, the corresponding priority of the calculation group can be calculated according to the unit capacity and the corresponding number of output modes of each unit. The specific priority calculation method can be as follows:

[0081]

[0082] in, is the priority of the i-th unit, is the capacity of the i-th unit, and A is the number of output modes of the i-th unit.

[0083] Among them, the units are also equipped with importance identification to distinguish key units from non-key units. Key units usually refer to large-capacity units or main power sources that play a key supporting role in system stability.

[0084] S12. If there are units with an importance mark of non-critical, the number of output modes of the units with the lowest priority and belonging to non-critical is reduced according to a preset reduction gradient to obtain a new number of output modes;

[0085] In this embodiment, if there are too many startup modes and there are currently non-critical units, the units with the lowest unit output combination W are reduced in sequence. If some units are more important, they will be designated as key units. After the number of gears for non-key units is reduced to a specified value (greater than or equal to 2), the number of gears for key units will be reduced.

[0086] Example: Three units, G1-G3. The upper and lower capacity limits are 0-1000, 400-1000, and 0-1200, respectively. Initially, they are evenly divided into five gears. G3 is the key unit, with a designated value of 2. The first operation reduces the number of G2 gears to 4 (W1=250, W2=150 before the operation), 400 / 600 / 800 / 1000. The second operation reduces the number of G2 gears to 3 (W1=250, W2=200 before the operation), 400 / 700 / 1000. The third operation reduces the number of G1 gears to 4 (W1=250, W2=300 before the operation), 0 / 333 / 666 / 1000. And so on.

[0087] For example, if there are 10 generators, each with four possible output modes, the number of possible combinations is 4^10 = 1,048,576. Consider switching each generator to three output modes, reducing the number of possible combinations to 3^10 = 59,049, which meets the requirement. In real-world power grids, power transmission areas with more than 10 generators are rare, and if only two output modes are possible, a maximum of 16 generators can be supported. Therefore, this threshold generally covers practical needs.

[0088] Among them, for the reduced output mode, the modes that have less impact on system stability (such as extremely low output mode or redundant gear) can be eliminated first.

[0089] Furthermore, during the step of reducing the number of startup modes, the number of gears for all units except key units was randomly reduced (or randomly reduced if the Wi difference fell below a certain level), rather than in a specific order. During further optimization, similar units were grouped together and their outputs were adjusted simultaneously. The number of gears was increased so that the output change for each gear change was equivalent to that of a single unit. In this case, assuming that the original three units each had five gears, the original 125 output options could be reduced to 15.

[0090] S13. If only the unit with the importance mark as the key exists, the number of output modes of the unit with the lowest priority is reduced according to the preset reduction gradient to obtain a new number of output modes;

[0091] If only key units exist, the key unit with the lowest priority is selected, and the number of its output modes is reduced according to the preset pressure reduction gradient to obtain a new number of output modes.

[0092] Among them, for the reduced output mode, high output mode (such as 100%, 80%) can be retained first, and low output mode (such as 30%, 20%) can be eliminated to reduce the impact on the system's power supply capacity.

[0093] S14: Jump to the step of determining the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes, until the initial number of output combinations is lower than the calculation threshold, thereby obtaining multiple initial unit output combinations;

[0094] In this embodiment, after each reduction, the initial number of unit output combinations is recalculated using the formula "number of units x number of new output modes." If the calculated result still exceeds a threshold (e.g., 10,000), the reduction process from S11 to S13 is repeated. If it falls below the threshold, the reduction is stopped, and the resulting combination becomes the initial unit output combination.

[0095] S15. Screening the initial unit output combinations to obtain multiple unit output combinations.

[0096] Furthermore, S15 may include the following sub-steps:

[0097] Sort the initial unit output combinations from high to low according to the total output upper limit to obtain a unit output combination sequence;

[0098] The partition method is used to divide the unit output combination sequence and obtain multiple optimized unit output combinations;

[0099] The optimized unit output combinations that are below the historical output lower limit are screened out to obtain a variety of unit output combinations.

[0100] In this embodiment, system stability deteriorates when units with high total output limits (and high inertia) have high output levels and low reserve capacity. To focus on high-output combinations that have a greater impact on system stability, redundant low-output combinations are eliminated. The total output limits of each initial unit output combination (i.e., the total power of all units in the combination at full output) are calculated and ranked from highest to lowest to form a unit output combination sequence. Furthermore, it is stipulated that the output of units with lower sequence numbers must be greater than or equal to that of units with higher sequence numbers.

[0101] For the sorted unit output combination sequence, the partition method principle is applied (dividing n unit elements into k output level categories) to calculate the number of optimized combinations. , and select the combination that meets the division rule from the sequence to obtain the optimized unit output combination.

[0102] Example: 4 units (n=4), 5 output levels (k=5), the number of optimized combinations after partitioning by the partition method is , which selects 70 optimized unit output combinations from the initial sequence that meet the rule that the output of the higher-numbered unit ≤ the output of the lower-numbered unit. For an initial number of possible combinations within 100,000, when n = 17 and k = 4, the maximum number of combinations after screening is 1,140. If the initial startup combination threshold set in the previous step is increased, the number of possible combinations will increase, but the increase will be limited. (For example, if n = 10 and k = 8, the number of possible combinations is 19,448, while the initial number of possible combinations is 10^8).

[0103] At the same time, the historical output lower limit is set according to the historical operating data of the target area. For example, the minimum safe startup total output of the area is 2376MW. The total output of each optimized unit output combination is calculated, and the combinations with total output lower than this value are eliminated to obtain a collection of multiple unit output combinations.

[0104] In another example of the present application, the method further includes:

[0105] If the initial number of output combinations does not exceed the calculation threshold, then all unit output combinations corresponding to the initial number of output combinations are obtained;

[0106] Jump to the steps of performing power flow calculation according to each unit output combination, determining the target unit output combination under the power flow convergence state and performing transient simulation, and determining the stabilization control results of each target unit output combination according to the simulation results.

[0107] In the embodiment of the present application, if the initial number of output combinations calculated for the first time does not exceed the calculation threshold, all unit output combinations corresponding to the number can be directly obtained, and step 104 can be skipped to improve data processing efficiency.

[0108] Step 104: Perform power flow calculations for each unit output combination in the target area, determine the target unit output combination under the power flow convergence state, perform transient simulation, and determine the stability control results of each target unit output combination;

[0109] The power flow convergence state refers to the state in which the calculation results meet the accuracy requirements (such as the calculation residuals of parameters such as voltage and power are within the allowable range) through iterative calculation during the power flow calculation process, indicating that the power system can operate stably under the output combination of the unit.

[0110] Transient simulation refers to a simulation method that simulates the dynamic behavior of the power system under transient processes such as faults (such as short circuit faults) and operations (such as unit switching), and analyzes the system's transient stability, equipment response, etc.

[0111] In this embodiment, a power system flow calculation model for the target area is constructed using power system analysis software such as PSASP and BPA. The grid topology, such as line parameters and transformer parameters, and various unit parameters, such as capacity, reactance, and regulation characteristics, are imported. Based on the settings for each unit output combination, a corresponding output mode is assigned to each device in each unit type. For example, in one combination, coal-fired units operate at 75% of rated output, while photovoltaic units operate at 40% output. A flow calculation algorithm is then used to perform flow calculations on each unit output combination. The calculation results determine whether the unit output combination is in a flow convergence state. If so, it is determined as the target unit output combination. If not, the target output combination is adjusted and the calculation is repeated until it meets the flow convergence state.

[0112] A transient simulation model is then built based on the power flow calculation model, supplemented with transient characteristic models of the units (such as the generator excitation system model and speed regulation system model) and fault models (such as setting common short-circuit fault types, including three-phase short circuits and single-phase ground faults, and setting the fault location and duration). The transient process after a fault occurs is then simulated for each target unit output combination, recording the system's dynamic response and the operation of the stabilization control devices during this process to generate stabilization control results.

[0113] In one example of the present application, step 104 may include the following sub-steps S21-S26:

[0114] S21, obtaining the power grid topology data corresponding to the target area;

[0115] S22, traverse the unit output combinations, and build a power flow calculation model according to the unit output combinations and power grid topology data;

[0116] S23, using a preset power flow algorithm to iteratively solve the power flow calculation model to obtain a power flow calculation result;

[0117] S24. If the power flow calculation result has not converged, the unit outputs within the target unit output combination are adjusted according to the power flow calculation result and the preset adjustment gradient to update the unit output combination;

[0118] S25, jump to the step of constructing a power flow calculation model according to the unit output combination and the grid topology data, until the power flow calculation results converge and the target unit output combination in the power flow convergence state is obtained;

[0119] In an embodiment of the present application, it can be extracted from a power grid dispatching automation system (such as SCADA / EMS) or a power grid planning database to ensure that the parameters are consistent with the actual operating status of the current power grid. The power grid topology data may include but is not limited to line parameters, transformer parameters, and node attributes. Traverse the unit output combinations, select one combination for analysis each time, and input the power grid topology parameters of the target area and the current unit output combination data into the flow calculation software (such as PSASP, BPA), specifically including: entering the unit output under the current combination at the power generation node (such as a thermal power unit output of 600MW, a hydropower unit output of 300MW); keeping the load value, line and transformer parameters of the load node unchanged, and forming a flow calculation model for the combination. The flow calculation model can be as follows:

[0120]

[0121]

[0122] in, Describes the relationship between the active power of node i and the node voltage amplitude V, voltage phase angle θ, and the inter-node conductance Gij and susceptance Bij. Reflects the relationship between the reactive power of node i and the node voltage amplitude V, voltage phase angle θ, and inter-node conductance Gij and susceptance Bij. i = 1, 2, ..., N, where N is the number of system nodes.

[0123] In this embodiment, the Newton-Raphson method can be used as the power flow solution algorithm to solve the power flow calculation model. The process is as follows: set the initial values: the voltage amplitude of each node (such as 1.0pu), the voltage phase angle (such as the phase angle of the balance node is 0°, and the other nodes are initially set to 0°); according to the power flow equation (active power Pi, reactive power Qi equation), the voltage amplitude and phase angle are corrected by the Jacobian matrix, and the active / reactive power error of each node is calculated; when the power error of all nodes is less than the preset accuracy (such as 10 -6 MW / Mvar), stop the iteration and output the power flow calculation results (voltage of each node, line power flow, power loss, etc.); if it has not converged, enter S24.

[0124] When the power flow calculation fails to converge, if the current combined total output is higher than the basic output, the output of some units in the combination will be reduced according to the preset adjustment gradient, such as 5% of the rated output / time. In addition, non-key units, such as new energy units, can be adjusted first. If the total output is lower than the basic output, the output of some units will be increased according to the gradient (large-capacity units, such as coal-fired units, will be adjusted first).

[0125] S26. Perform transient simulation using the target unit output combination, and determine the stability control results of each target unit output combination according to the simulation results.

[0126] Furthermore, S26 may include the following sub-steps:

[0127] The transient simulation topology model is constructed using the output combination of each target unit;

[0128] The preset transient simulation software is used to simulate each transient simulation topology model according to the preset fault type to obtain the stability control results.

[0129] In this application example, typical severe power grid faults are simulated, such as a 220kV three-phase short circuit (the fault line is disconnected after the fault persists for 0.1s) and an N-2 fault (two parallel lines trip simultaneously). The fault trigger time is set in the software (e.g., t=1s), and the simulation is run until 30s after the fault (to ensure that the transient process has completely decayed). The system dynamic response is recorded:

[0130] Power angle curve: the change of the power angle of each generator rotor over time (to determine whether there is divergence and instability);

[0131] Voltage / frequency curve: voltage amplitude at key nodes and fluctuations in system frequency (e.g., voltage temporarily drops to 0.7 pu and frequency drops to 49.2 Hz);

[0132] Action of the stabilization control device: record the action of the stabilization control system after a fault (such as the time and amount of action when a unit's 500MW output or 100MW load is cut off).

[0133] According to the simulation records, determine whether the system has recovered to stability after the stabilization control action (the power angle converges, and the voltage / frequency returns to the normal range), and form the "stabilization control result" of the target unit output combination (such as "stable after stabilization control action" and "unstable after stabilization control action").

[0134] Step 105: According to each stabilization control result, the output limit corresponding to the target area is determined and regulated.

[0135] The transient simulation results for each target unit output combination are analyzed and combined with the stabilization control actions to determine the system's transient stability. If, for a given unit output combination, the system still experiences instability such as power angle divergence or voltage collapse even after the stabilization control device is activated, the output level corresponding to that combination exceeds the system's stability tolerance. If the system stabilizes after the stabilization control action, the output level for that combination is recorded. By traversing all target unit output combinations and comprehensively considering factors such as different fault types and the effectiveness of the stabilization control actions, the maximum output level at which the units in the target area can safely operate while ensuring system transient stability is determined, known as the output limit. For example, by comparing the transient simulation results for different combinations, it was found that when the total output of the regional units reaches a certain value, the stabilization control action can effectively maintain stability under fault conditions. However, above this value, stability cannot be achieved. This value is the output limit. Based on the determined output limit and the current actual system output, a control strategy is formulated. If the actual output is close to or exceeds the output limit, measures can be taken to adjust the unit output, such as reducing the output of some large-capacity units and optimizing the output distribution of new energy units (on the premise of ensuring absorption); or through demand-side management, load-side electricity consumption can be adjusted (such as guiding high-energy-consuming loads to use electricity off-peak).

[0136] Furthermore, the grid dispatching command system can be used to send control commands to power plants and load-side operators to adjust unit output and load power consumption. During the control process, a real-time monitoring system is used to track the power system's operating parameters (voltage, frequency, power, etc.) to ensure that the system operates safely and stably after control, and that unit output is controlled within output limits. Simultaneously, the system undergoes continuous analysis and verification through power flow calculations and transient simulations, dynamically adjusting control strategies based on actual operating conditions.

[0137] In one example of the present application, step 105 may include the following sub-steps:

[0138] Select the target action result that is stable after the stabilization action from each stabilization control result;

[0139] According to the target unit output combination associated with the target action result, the total output under different numbers of units is selected and rounded to obtain the output limit corresponding to the target area;

[0140] Adjust the operation control requirements or output setting values ​​corresponding to the target area according to the output limit.

[0141] In this embodiment, the transient simulation stabilization control results for each unit output combination are filtered out to identify records showing "stable after stabilization control action" as target action results. The target action results are then grouped according to the target unit output combination associated with each unit, i.e., the number of units in operation (e.g., 2, 3, 4). The total output for each unit number is selected and rounded to the nearest integer to obtain the output limit corresponding to the target region. Finally, the operational control requirements are refined based on these output limits, or the output setting value of the stabilization control device is optimized.

[0142] Specifically, the detailed operation control requirements are as follows:

[0143] 1. Set constraints based on the number of units in operation

[0144] 2-unit operation mode: Combined with transient simulation results (e.g., the total output of 2376MW of unit 1 stabilizes after stabilization control action), it is determined that there is no need to limit the total output level, but the unit's spare capacity must be monitored (to ensure sufficient regulation capability in the event of a fault), requiring the spinning reserve to be no less than 10% of the total output (i.e., ≥237.6MW).

[0145] 3-unit operation mode: The maximum stable total output is 3006MW, so the control requirement is set to "total output strictly less than 3000MW". At the same time, the output constraints of individual units are refined: the output of units with a total output upper limit of 1188MW (such as #1 and #2) shall not exceed 1000MW, and the output of units with a total output upper limit of 1086MW (such as #3 and #4) shall not exceed 900MW. This avoids excessive impact in the event of a failure due to excessive output of a single unit.

[0146] 4-unit operation mode: The maximum stable total output is 3636MW (serial number 16), but considering the comprehensive safety margin and the stability boundary of other combinations, the control requirement is set to "total output less than 3400MW", and the output proportion of each unit is clearly defined: the total output of units with a total output upper limit of 1188MW shall not exceed 2376MW (two units at full output), and the total output of units with a total output upper limit of 1086MW shall not exceed 1738MW (two units at 80% output), to prevent instability caused by uneven output distribution (such as serial number 15 causing 3549MW instability due to unreasonable output distribution).

[0147] 2. Fault scenario correlation control strategy

[0148] For N-1 faults (such as a single tie line tripping), rapid load reduction measures are required to be automatically activated (with the load reduction amount not less than 5% of the total output) when the section power exceeds 2800MW in the 3-machine and 4-machine modes;

[0149] For N-2 faults (such as simultaneous tripping of two tie lines), the emergency generator tripping strategy is triggered: in the three-machine mode, the unit with the lower total output limit (such as #3) is prioritized for tripping. In the four-machine mode, the standard of "cutting 10% of the total output" is followed to ensure that the power angle swing angle is ≤120° after the fault.

[0150] 3. Basis for setting threshold value

[0151] Combined with the cross-sectional power distribution of all “stable after stabilization control action” combinations (such as 2868MW for sequence number 10 and 3462MW for sequence number 14), the lower limit of the critical interval between stability and instability (2800-3000MW) of 2800MW is taken as the threshold value to ensure sufficient margin.

[0152] The threshold value needs to be dynamically adjusted: when the regional load increases by more than 5%, the threshold value is lowered by 3% (e.g. 2800MW→2716MW); when a new unit is put into operation (e.g. adding a 600MW thermal power unit), the threshold value is raised by 5% (e.g. 2800MW→2940MW).

[0153] 4. Action logic refinement

[0154] Level 1 action: When the cross-section power is ≥2800MW and a fault occurs, the output of the 200MW unit will be immediately cut off (hydropower units will be cut off first because of their fast regulation response);

[0155] Secondary action: If the power angle continues to increase (exceeds 90°) after the primary action, an additional 300MW of output will be cut off within 100ms to ensure that the system returns to stability within 5 seconds.

[0156] Locking condition: When the system frequency is lower than 49.5Hz, the generator is locked and the low-frequency load reduction is performed first to avoid frequency collapse.

[0157] In a specific implementation, the specific implementation process of the above steps 101-105 can be implemented through the following example:

[0158] There are four units in a certain power transmission area, which are divided into two categories, with output limits of 1086MW and 1188MW respectively. Each unit has four output levels: 0%, 50%, 80% and 100%.

[0159] There are 256 possible output modes, which is less than 100,000. This can be simplified directly using the method in step 3 of the process. Furthermore, since the minimum number of units in operation in this area is typically two, the lower output limit is set to 2376MW (=1188*2).

[0160] After screening, there are 22 starting combinations that meet the requirements, which is a significant decrease compared to the theoretically possible output modes. See below for details.

[0161] Adjust the operating mode according to the startup combination. For the startup combination to be calculated, if the total output exceeds the basic mode output, reduce the output of other units; otherwise, increase the output of other units.

[0162] The system stability after the preset fault occurs in the transient simulation system is classified and sorted by the number of units in operation. The results are shown in Table 1 below:

[0163] Table 1

[0164]

[0165] Based on the results in the table above, the following control recommendations can be made: If two turbines are operating in this area, there is no need to limit the total output level; if three turbines are operating in this area, the output level should be limited to less than 3000MW; if four turbines are operating in this area, the output level should be limited to less than 3400MW. If a stabilizing control device is used, the set value should take into account adaptability and margin, and the threshold value can be set at 2800MW.

[0166] As can be seen, the total output of operating mode 16 was 3636 MW, higher than the 3549 MW of operating mode 15. However, the former recovered after stabilization control, while the latter became unstable. This phenomenon shows that the stability of the region after a fault is related to both the total regional output level and the specific output of each unit. If this technology is not implemented, either this situation may be ignored, leading to system instability during a fault, or only a larger margin can be retained, reducing the economic efficiency of grid operation.

[0167] Admittedly, this specific example is relatively simple, and even fully calculating all possible startup scenarios is not difficult. However, as shown in the preceding analysis, if the number of units is large and the number of possible startup gears is also large, the number of possible startup combinations without simplification is likely to exceed the computational capacity (for example, calculating one possible combination would take one minute, while calculating 100,000 possible combinations would take over two months, and the number increases exponentially with the number of units and possible startup gears). However, calculating all possible startup scenarios with simplification is feasible.

[0168] In this embodiment, if a fault occurs in a densely loaded area and causes problems such as low voltage instability or line overload, load shedding is required to restore stability. A method similar to that proposed in this embodiment can be used to determine system stability at different load levels and the corresponding control measures required.

[0169] In the embodiment of the present application, the number of units and the number of output modes of each type of unit in the target area are obtained; according to the number of units and the number of output modes, the initial number of output combinations corresponding to the target area is determined; if the initial number of output combinations exceeds the calculation threshold, the number of output modes is reduced according to the unit capacity of the unit, and multiple unit output combinations are determined; according to each unit output combination, the target area is calculated separately for the flow, the target unit output combination under the flow convergence state is determined and transient simulation is performed to determine the stability control results of each target unit output combination; according to each stability control result, the output limit corresponding to the target area is determined and regulated. Thus, by combining the unit capacity reduction with the flow calculation and transient simulation, the unit output combination can be effectively and quickly screened, thereby achieving accurate quantification of the delivery capacity and providing accurate setting values.

[0170] See also Figure 2 , Figure 2 This is a structural block diagram of a regional output limit control device provided by an embodiment of the present invention.

[0171] An embodiment of the present invention provides a regional output limit control device, comprising:

[0172] The quantity acquisition module 201 is used to obtain the number of units and the number of output modes of each type of unit in the target area;

[0173] The output combination initial number determination module 202 is used to determine the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes;

[0174] The output mode reduction module 203 is configured to reduce the number of output modes according to the unit capacity if the initial number of output combinations exceeds the calculated threshold, and determine multiple unit output combinations;

[0175] The stability control result determination module 204 is used to perform power flow calculations for each unit output combination in the target area, determine the target unit output combination under the power flow convergence state, perform transient simulation, and determine the stability control results for each target unit output combination;

[0176] The stabilization control adjustment module 205 is used to determine the output limit corresponding to the target area and perform regulation according to each stabilization control result.

[0177] Optionally, the output combination initial quantity determination module 202 is specifically configured to:

[0178] Perform power operations on the number of output modes according to the number of units to obtain the number of output mode combinations corresponding to each unit;

[0179] Calculate the multiplication value between the number of output mode combinations to obtain the initial number of output combinations corresponding to the target area.

[0180] Optionally, the output mode reduction module 203 includes:

[0181] The priority calculation submodule is used to calculate the priority of each unit according to the unit capacity and the corresponding number of output modes if the initial number of output combinations exceeds the calculation threshold; the units are also equipped with importance identification;

[0182] A first quantity reduction submodule is configured to reduce the number of output modes of the units with the lowest priority and belonging to the non-key units according to a preset reduction gradient if there are units with a non-key importance mark, to obtain a new number of output modes;

[0183] The second quantity reduction submodule is configured to reduce the number of output modes of the unit with the lowest priority according to a preset reduction gradient if only the unit with the importance mark is present, to obtain a new number of output modes;

[0184] A loop submodule is used to jump to the step of determining the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes, until the initial number of output combinations is lower than the calculation threshold, thereby obtaining multiple initial unit output combinations;

[0185] The combination screening submodule is used to screen the initial unit output combinations to obtain multiple unit output combinations.

[0186] Optionally, the combined screening submodule is specifically used to:

[0187] Sort the initial unit output combinations from high to low according to the total output upper limit to obtain a unit output combination sequence;

[0188] The partition method is used to divide the unit output combination sequence and obtain multiple optimized unit output combinations;

[0189] The optimized unit output combinations that are below the historical output lower limit are screened out to obtain a variety of unit output combinations.

[0190] Optionally, the stabilization control result determination module 204 includes:

[0191] The data acquisition submodule is used to obtain the power grid topology data corresponding to the target area;

[0192] The power flow calculation model construction submodule is used to traverse the unit output combination and build the power flow calculation model according to the unit output combination and power grid topology data;

[0193] The iterative solution submodule is used to iteratively solve the power flow calculation model using a preset power flow algorithm to obtain the power flow calculation results;

[0194] The combination update submodule is used to adjust the unit outputs in the target unit output combination according to the power flow calculation results and the preset adjustment gradient to update the unit output combination if the power flow calculation results have not converged;

[0195] The power flow convergence submodule is used to jump to the step of building a power flow calculation model according to the unit output combination and the grid topology data until the power flow calculation results converge and the target unit output combination in the power flow convergence state is obtained;

[0196] The transient simulation submodule is used to perform transient simulation using the target unit output combination and determine the stability control results of each target unit output combination according to the simulation results.

[0197] Optionally, the transient simulation submodule is specifically used to:

[0198] The transient simulation topology model is constructed using the output combination of each target unit;

[0199] The preset transient simulation software is used to simulate each transient simulation topology model according to the preset fault type to obtain the stability control results.

[0200] Optionally, the stabilization and adjustment module 205 is specifically configured to:

[0201] Select the target action result that is stable after the stabilization action from each stabilization control result;

[0202] According to the target unit output combination associated with the target action result, the total output under different numbers of units is selected and rounded to obtain the output limit corresponding to the target area;

[0203] Adjust the operation control requirements or output setting values ​​corresponding to the target area according to the output limit.

[0204] Optionally, the stabilization jump module is specifically used to:

[0205] If the initial number of output combinations does not exceed the calculation threshold, then all unit output combinations corresponding to the initial number of output combinations are obtained;

[0206] Jump to the steps of performing power flow calculation according to each unit output combination, determining the target unit output combination under the power flow convergence state and performing transient simulation, and determining the stabilization control results of each target unit output combination according to the simulation results.

[0207] An embodiment of the present invention further provides an electronic device, characterized in that it includes a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the regional output limit control method as described in any embodiment of the present invention.

[0208] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0209] In the several embodiments provided in this application, it should be understood that the disclosed 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 modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0210] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0211] In addition, the functional modules in various embodiments of the present invention may be integrated into a single processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0212] 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 controlling regional output limit, characterized in that: include: Obtain the number of units and output modes of each type of unit in the target area; Determining an initial number of output combinations corresponding to the target area according to the number of units and the number of output modes; If the initial number of the output combinations exceeds the calculation threshold, the number of the output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations; Performing power flow calculations on the target area according to each of the unit output combinations, determining the target unit output combination under the power flow convergence state, and performing transient simulation to determine the stability control results of each of the target unit output combinations; According to the stabilization control results, the output limit corresponding to the target area is determined and regulated.

2. The method according to claim 1, characterized in that The determining, according to the number of units and the number of output modes, an initial number of output combinations corresponding to the target area includes: Performing power operations on the number of output modes according to the number of each unit to obtain the number of output mode combinations corresponding to each unit; The multiplication value between the output mode combination numbers is calculated to obtain the initial number of output combinations corresponding to the target area.

3. The method according to claim 1, characterized in that If the initial number of output combinations exceeds a calculation threshold, the number of output modes is reduced according to the unit capacity of the unit to determine multiple unit output combinations, including: If the initial number of output combinations exceeds the calculation threshold, the priority of each unit is calculated according to the unit capacity and the corresponding number of output modes of each unit; the unit is also provided with an importance identifier; If there is a unit with the importance mark as non-key, the number of output modes of the unit with the lowest priority and belonging to non-key is reduced according to the preset reduction gradient to obtain a new number of output modes; If there is only a unit with the importance mark as the priority, the number of output modes of the unit with the lowest priority is reduced according to the preset reduction gradient to obtain a new number of output modes; Jumping to the step of determining the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes, until the initial number of output combinations is lower than the calculation threshold, thereby obtaining a plurality of initial unit output combinations; The initial unit output combinations are screened to obtain multiple unit output combinations.

4. The method according to claim 3, characterized in that The initial unit output combinations are screened to obtain multiple unit output combinations, including: Sort the initial unit output combinations from high to low according to the total output upper limit to obtain a unit output combination sequence; The unit output combination sequence is divided by using a partition method to obtain multiple optimized unit output combinations; The optimized unit output combinations that are below the historical output lower limit are screened out to obtain a variety of unit output combinations.

5. The method according to claim 1, wherein The method of performing power flow calculation for each of the target unit output combinations for the target area, determining the target unit output combination under the power flow convergence state and performing transient simulation, and determining the stabilization control result of each target unit output combination according to the simulation result, includes: Acquiring power grid topology data corresponding to the target area; Traversing the unit output combinations, and building a power flow calculation model according to the unit output combinations and the power grid topology data; Iteratively solving the power flow calculation model using a preset power flow algorithm to obtain a power flow calculation result; If the power flow calculation result has not converged, adjusting the unit outputs within the target unit output combination according to the power flow calculation result and a preset adjustment gradient to update the unit output combination; Jump to the step of constructing a power flow calculation model according to the unit output combination and the grid topology data until the power flow calculation result converges and a target unit output combination in a power flow convergence state is obtained; The target unit output combinations are used to perform transient simulation, and the stabilization control results of the target unit output combinations are determined according to the simulation results.

6. The method according to claim 5, characterized in that The step of performing transient simulation using the target unit output combination to determine the stabilization control results of each target unit output combination includes: Using each target unit output combination to construct a transient simulation topology model; The preset transient simulation software is used to simulate each of the transient simulation topology models according to the preset fault type to obtain a stabilization result.

7. The method according to claim 1, characterized in that Determining the output limit corresponding to the target area and performing regulation according to each of the stabilization control results includes: Selecting a target action result that is stable after the stabilization action from each of the stabilization control results; According to the target unit output combination associated with the target action result, the total output under different numbers of units is selected and rounded to obtain the output limit corresponding to the target area; The operation control requirements or output setting values ​​corresponding to the target area are adjusted according to the output limit.

8. The method according to any one of claims 1 to 7, characterized in that The method further comprises: If the initial number of output combinations does not exceed the calculation threshold, then obtaining all unit output combinations corresponding to the initial number of output combinations; Jump to the step of performing power flow calculation according to each of the unit output combinations, determining the target unit output combination under the power flow convergence state and performing transient simulation, and determining the stabilization control result of each target unit output combination according to the simulation result.

9. A regional output limit control device, characterized in that: include: The quantity acquisition module is used to obtain the number of units and output modes of each type of unit in the target area; an output combination initial number determination module, configured to determine the initial number of output combinations corresponding to the target area according to the number of units and the number of output modes; an output mode reduction module, configured to reduce the number of output modes according to the unit capacity of the unit if the initial number of the output combinations exceeds a calculation threshold, and determine multiple unit output combinations; a stabilization control result determination module, configured to perform power flow calculations for the target area according to each of the power unit output combinations, determine the target power unit output combination under the power flow convergence state, perform transient simulation, and determine the stabilization control results for each of the target power unit output combinations; The stabilization control adjustment module is used to determine the output limit corresponding to the target area and perform regulation according to each of the stabilization control results.

10. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the regional output limit control method according to any one of claims 1 to 8.

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