Method and device for emergency control of multi-modal wideband oscillations of power systems

Abstract

Embodiments of the present application provide a multi-modal wide-frequency oscillation emergency control method and device for a power system. The method comprises: obtaining an oscillation tracing analysis result of the power system, and determining a target mode group based on the oscillation tracing analysis result, wherein the oscillation tracing analysis result comprises a plurality of mode groups and a cross-frequency domain net oscillation power of a monitoring node for each mode group; screening the target mode group based on the cross-frequency domain net oscillation power and a preset screening condition to generate a candidate oscillation source set; generating an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power; generating an initial unit set based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power and the initial control priority list; iteratively optimizing the initial unit set to generate a target unit set; and issuing a unit tripping instruction for the target unit set to trip the target unit set. Thus, the target mode can be accurately locked, and the oscillation source can be efficiently blocked.

Description

Technical Field

[0001] This application relates to the field of power system safety technology, and in particular to an emergency control method and device for multimodal broadband oscillations in power systems. Background Technology

[0002] With the rapid development of new power systems based on new energy sources, the problem of multimodal broadband oscillations caused by power electronic devices is becoming increasingly serious. These oscillations are characterized by multimodal concurrency, complex coupling, and rapid divergence, posing a significant threat to power grid security. When such oscillations occur in the system and negative damping modes are identified by online monitoring, emergency control measures must be initiated to quickly interrupt the oscillation energy and prevent system instability.

[0003] Existing emergency control strategies primarily target instability modes dominated by traditional synchronous machines, and their decision criteria (such as overfrequency and undervoltage) are inconsistent with the physical mechanisms of broadband oscillations. Although progress has been made in oscillation source localization technology based on wide-area measurement systems, transforming the localization results into fast, reliable, and cost-effective multi-objective collaborative machine-switching decisions remains an engineering challenge. The main challenges are: 1) Complex decision dimensions: Multiple oscillation modes need to be stabilized simultaneously, but the impact of a single control measure on different modes may conflict; 2) The contradiction between model dependence and real-time performance: Precise model-based optimization methods cannot meet the requirements of second-level decision-making, while simple rule-based methods cannot guarantee global optimality; 3) Uncertainty: The system's operating modes are highly variable, and offline strategies have poor adaptability. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, the first objective of this application is to propose an emergency control method for multi-mode broadband oscillations in power systems, which can accurately pinpoint the oscillation mode that most needs to be controlled, effectively identify the generating unit that actually contributes to the oscillation, prioritize the allocation of limited control resources to the unit with the highest cost-effectiveness, generate an initial tripping scheme that meets safety requirements in a very short time, and minimize the tripping cost through finite-step iteration, and finally execute the tripping quickly to block the oscillation propagation.

[0006] The second objective of this application is to provide an emergency control device for multimodal broadband oscillations in a power system.

[0007] To achieve the above objectives, the first aspect of this application proposes an emergency control method for multimodal broadband oscillations in a power system, comprising: acquiring the oscillation source analysis results of the power system, and determining a target mode group based on the oscillation source analysis results, wherein the oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of monitoring nodes for each mode group; filtering the target mode group based on the cross-frequency domain net oscillation power and preset screening conditions to generate a candidate oscillation source set; generating an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power; generating an initial unit set based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list; iteratively optimizing the initial unit set to generate a target unit set; and issuing a tripping command to the target unit set to trip the target unit set.

[0008] In addition, the emergency control method for multi-mode broadband oscillation of a power system according to the above embodiments of this application may also have the following additional technical features: According to one embodiment of this application, determining the target mode group based on the oscillation source analysis results includes: calculating the comprehensive threat assessment index for each mode group based on the oscillation source analysis results; and taking the mode group corresponding to the maximum value in the comprehensive threat assessment index as the target mode group.

[0009] According to one embodiment of this application, the oscillation source analysis results also include the mode group damping ratio and the total number of monitoring nodes. The comprehensive threat assessment index is calculated in the following way:

[0010] Where m represents the index of the mode group, and m is a positive integer. This represents the absolute value of the modal group damping ratio of modal group m. This represents the number of nodes in mode group m whose net oscillation power across the frequency domain is negative. S Indicates the total number of monitoring nodes. This represents the absolute value of the net oscillation power across the frequency domain of mode group m.

[0011] According to one embodiment of this application, generating an initial control priority list based on a candidate oscillator set and cross-frequency domain net oscillation power includes: calculating the cutoff power efficiency index of candidate oscillators in the candidate oscillator set based on the cross-frequency domain net oscillation power; and sorting the candidate oscillators in descending order based on the cutoff power efficiency index to generate the initial control priority list.

[0012] According to one embodiment of this application, the power cutoff performance index is calculated in the following manner:

[0013] Where j represents the index of the candidate oscillation source and j is a positive integer. This represents the active power capacity of candidate oscillation source j. This represents the net oscillation power across the frequency domain of candidate oscillation source j.

[0014] According to one embodiment of this application, a power system includes multiple generating units. The generation of an initial set of generating units based on a preset search method, a preset sensitivity coefficient, cross-frequency domain net oscillation power, and an initial control priority list includes: searching for candidate oscillation sources in the initial control priority list using the preset search method to determine a target oscillation source, and using the generating unit corresponding to the target oscillation source as the initial generating unit; calculating the predicted improvement amount of the target generating unit based on the preset sensitivity coefficient and cross-frequency domain net oscillation power; and generating the initial set of generating units based on the target generating unit in response to the predicted improvement amount satisfying a preset search cutoff condition.

[0015] According to one embodiment of this application, the predicted improvement amount is calculated in the following manner:

[0016] Where j represents the unit number and j is a positive integer. This represents the preset sensitivity coefficient. This represents the absolute value of the negative oscillation power of unit j with respect to mode group m. It is derived from the net oscillation power across the frequency domain.

[0017] According to one embodiment of this application, iterative optimization of an initial set of generating units to generate a target set of generating units includes: generating a neighborhood solution of the generating units based on the initial set of generating units; and iteratively optimizing the neighborhood solution of the generating units based on a preset optimization objective and a preset auxiliary objective to generate the target set of generating units.

[0018] According to one embodiment of this application, after switching the target set of generating units, the method further includes: obtaining the actual improvement amount of the power system, and updating the preset sensitivity coefficient based on the actual improvement amount and the preset update algorithm.

[0019] To achieve the above objectives, a second aspect of this application proposes an emergency control device for multi-mode broadband oscillations in a power system, comprising: an acquisition module for acquiring oscillation source analysis results of the power system and determining target mode groups based on the oscillation source analysis results, wherein the oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of monitoring nodes for each mode group; a screening module for screening the target mode groups based on the cross-frequency domain net oscillation power and preset screening conditions to generate a candidate oscillation source set; a first generation module for generating an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power; a second generation module for generating an initial unit set based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list; an optimization module for iteratively optimizing the initial unit set to generate a target unit set; and a control module for issuing a tripping command to the target unit set to trip the target unit set.

[0020] The multi-mode broadband oscillation emergency control device for power systems according to this application implements the aforementioned multi-mode broadband oscillation emergency control method for power systems. It can accurately pinpoint the oscillation mode most in need of control, effectively identify the generating unit that actually contributes to the oscillation, prioritize the allocation of limited control resources to the most cost-effective unit, generate an initial tripping scheme that meets safety requirements in a very short time, and minimize the tripping cost through finite-step iterations, ultimately executing the tripping quickly to prevent oscillation propagation. Attached Figure Description

[0021] Figure 1 This is a flowchart of an emergency control method for multimodal broadband oscillations in a power system according to some embodiments of this application; Figure 2 This is a flowchart of an emergency control method for multimodal broadband oscillations in a power system according to a specific embodiment of this application; Figure 3 This is a block diagram of a multimode broadband oscillation emergency control device for a power system according to some embodiments of this application. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0023] The following describes in detail, with reference to the accompanying drawings, the emergency control method and apparatus for multimodal broadband oscillation of a power system according to embodiments of this application.

[0024] Figure 1This is a flowchart of an emergency control method for multimodal broadband oscillations in a power system according to some embodiments of this application. (Refer to...) Figure 1 Emergency control methods for multimodal broadband oscillations in power systems may include: S1. Obtain the oscillation source analysis results of the power system, and determine the target mode group based on the oscillation source analysis results. The oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of the monitoring node for each mode group.

[0025] Among them, the oscillation source tracing analysis result refers to the analysis output provided in real time by the front-end oscillation source tracing system.

[0026] Furthermore, the oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of each mode group for each monitoring node.

[0027] In this context, a mode group refers to a set of multiple coupled oscillation modes in a power system, each with a specific oscillation frequency range. Monitoring nodes are data acquisition points deployed at key locations in the power system, such as grid connection points of new energy power plants or important hub substations, responsible for the synchronous acquisition of local voltage and current signals and high-precision measurement of broadband phasors. The mode group reflects the frequency domain distribution characteristics of the oscillations, while monitoring nodes provide spatial distribution information of the oscillation energy; together, they form the basis for tracing the source of broadband oscillations.

[0028] The cross-frequency domain net oscillation power refers to the power contribution calculated at a monitoring node or power generation unit for a certain mode group. The sign of the value indicates whether the node plays an oscillation damping or oscillation boosting role for the mode group. A negative value indicates that the node boosts the oscillation, i.e., it belongs to the oscillation source.

[0029] The target mode group can refer to the primary control object selected from all negatively damped mode groups that requires priority emergency control.

[0030] In some embodiments of this application, determining the target mode group based on the oscillation source analysis results includes: calculating the comprehensive threat assessment index for each mode group based on the oscillation source analysis results; and taking the mode group corresponding to the maximum value in the comprehensive threat assessment index as the target mode group.

[0031] Among them, the comprehensive threat assessment index is a quantitative indicator that integrates three dimensions: divergence speed, energy scale, and propagation breadth, and is used to comprehensively measure the degree of threat posed by each mode group to the security of the power system.

[0032] The magnitude of the comprehensive threat assessment index indicates the level of threat posed by the mode group to the system. The larger the index value, the stronger the divergence trend of the mode group, the larger the oscillation energy scale, the more dispersed the oscillation source distribution, and the more serious the comprehensive threat to power system security.

[0033] In some embodiments of this application, the oscillation source analysis results also include the mode group damping ratio and the total number of monitoring nodes. The comprehensive threat assessment index is calculated in the following way:

[0034] (1) In the formula, This represents the comprehensive threat assessment index for mode group m, where m represents the index of the mode group and is a positive integer. This represents the absolute value of the modal group damping ratio of modal group m. This represents the number of nodes in mode group m whose net oscillation power across the frequency domain is negative. S Indicates the total number of monitoring nodes. This represents the absolute value of the net oscillation power across the frequency domain of mode group m.

[0035] The mode group damping ratio is a characteristic parameter reflecting the divergence or convergence trend of the mode group oscillations. The mode group damping ratio can be estimated online from broadband phasors using algorithms such as Prony analysis and Hilbert transform. When the damping ratio is negative, it indicates that the mode group is in a negatively damped state, and the oscillations exhibit a divergent trend; the larger the absolute value of the damping ratio, the faster the divergence rate and the higher the risk of intensified oscillations.

[0036] The number of nodes with negative net oscillation power across the frequency domain refers to the number of nodes with negative net oscillation power among all monitored nodes in this mode group. A negative value indicates that the node contributes to the oscillation, i.e., it is an oscillation source. The ratio of this parameter to the total number of monitored nodes reflects the degree of dispersion of oscillation sources. The larger the ratio, the more nodes participate in contributing to the oscillation, the more global the oscillation mode tends to be, and the higher the overall threat to the system.

[0037] The comprehensive threat assessment index measures the actual threat level of each mode group to power system security from multiple key dimensions, avoiding the one-sided judgment that may result from relying on a single indicator.

[0038] Specifically, this indicator integrates information from three aspects: First, by introducing the absolute value of the mode group damping ratio, the index reflects the divergence rate of the oscillation. The larger the absolute value of the damping ratio, the more severe the negative damping of the mode group, the faster the oscillation diverges, the higher the risk of system instability, and the more priority it needs to be addressed.

[0039] Second, by introducing the logarithmic form of the total network oscillation energy, the index reflects the energy scale of the oscillation. The larger the total oscillation energy accumulated in the system by this mode, the wider the range of the oscillation, the more concentrated the energy, and the greater the impact on equipment and the destructive force on the system. Using logarithmic processing can prevent a single value from being too large and dominating the calculation result of the entire index.

[0040] Third, by introducing the ratio of the number of negative oscillation power nodes to the total number of monitoring nodes, the indicator reflects the degree of dispersion of the oscillation source. The larger this ratio, the more nodes contribute to the mode group, and the oscillation is not caused by a single local source, but by the joint participation of multiple nodes, exhibiting global characteristics. Such global oscillations are more difficult to control than local oscillations and pose a more serious threat to system security.

[0041] In summary, the significance of this indicator lies in its organic unification of three independent dimensions: divergence trend, energy scale, and source distribution. This allows for an objective ranking of the urgency of each modal group. Prioritizing the modal group corresponding to the maximum value of the indicator as the primary target for emergency control ensures that control resources are allocated to the oscillation modes with the highest systemic risk and the greatest overall harm, thereby improving the targeting and effectiveness of emergency control.

[0042] The modality group corresponding to the maximum value in the comprehensive threat assessment index is taken as the target modality group, that is:

[0043] This means that from all negatively damped mode groups, the one with the greatest overall threat is selected as the primary target for this emergency control, so as to ensure that control measures prioritize the oscillation mode with the highest systemic risk and the most urgent need for suppression.

[0044] S2, the target mode group is screened based on the cross-frequency domain net oscillation power and preset screening conditions to generate a candidate oscillation source set.

[0045] Here, the preset screening criteria refer to the judgment criteria used to determine whether a power generation unit belongs to the candidate oscillation source. For example, if for the target mode group... m target Power generation unit j The cross-frequency domain net oscillation power satisfies < P th ( P th If the threshold is negative, these units are identified as oscillation sources and can form a candidate oscillation source set, which serves as the basis for subsequent calculation of control priority and execution of machine switching decisions.

[0046] The negative threshold is a negative number preset by technicians based on the actual operating characteristics and control requirements of the power system. Its specific value is not limited in this application, as long as the power generation unit that contributes to the oscillation can be identified.

[0047] S3 generates an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power.

[0048] The initial control priority list is a sequential list obtained by sorting candidate oscillation sources according to their control effectiveness. It is used to guide subsequent emergency control decisions on which units to prioritize. The higher the oscillation source is ranked in the list, the higher the cost-effectiveness of eliminating it, and it should be included in the control plan first.

[0049] In some embodiments of this application, generating an initial control priority list based on a set of candidate oscillators and cross-frequency domain net oscillation power includes: calculating the cutoff power efficiency index of candidate oscillators in the candidate oscillator set based on the cross-frequency domain net oscillation power; and sorting the candidate oscillators in descending order based on the cutoff power efficiency index to generate an initial control priority list.

[0050] The power cut-off efficiency index is a quantitative parameter that measures the amount of target oscillation power that can be eliminated by cutting off a unit of active power. It is used to evaluate the control efficiency of each candidate oscillation source. The larger the index value, the more oscillation power can be suppressed per unit capacity of the oscillation source, and the better the control effect.

[0051] In some embodiments of this application, the cutoff power performance index is calculated in the following manner:

[0052] (3) In the formula, The power efficiency index is represented by , and j represents the index of the candidate oscillation source, where j is a positive integer. This represents the active power capacity of candidate oscillation source j. This represents the net oscillation power across the frequency domain of candidate oscillation source j.

[0053] The active capacity of candidate oscillation source j refers to the rated active power that the power generation unit can output, reflecting the power cost required to disconnect the unit.

[0054] Furthermore, candidate oscillation sources are sorted in descending order based on the cut-off power efficiency index to generate an initial control priority list. That is, oscillation sources with larger cut-off power efficiency index values ​​are placed at the top of the list, and those with smaller values ​​are placed at the bottom, thus forming a control priority order from high to low.

[0055] S4 generates an initial set of generator units based on a preset search method, preset sensitivity coefficient, cross-frequency domain net oscillation power, and initial control priority list.

[0056] In some embodiments of this application, the power system includes multiple generating units. The generation of an initial generating unit set based on a preset search method, a preset sensitivity coefficient, cross-frequency domain net oscillation power, and an initial control priority list includes: searching for candidate oscillation sources in the initial control priority list using the preset search method to determine a target oscillation source, and using the generating unit corresponding to the target oscillation source as the initial generating unit; calculating the predicted improvement amount of the target generating unit based on the preset sensitivity coefficient and cross-frequency domain net oscillation power; and generating the initial generating unit set based on the target generating unit in response to the predicted improvement amount satisfying a preset search cutoff condition.

[0057] For example, the preset search method can refer to a forward greedy search strategy, which starts from the top of the initial control priority list and sequentially adds candidate oscillation sources to the temporary set, evaluating their effectiveness after each addition, until a preset search cutoff condition is met. The specific implementation of this search method can be selected according to actual needs, and this application does not limit it.

[0058] Candidate oscillation sources in the initial control priority list are examined one by one in order of priority from high to low, and the oscillation source currently being examined is taken as the target oscillation source.

[0059] Furthermore, the generator sets associated with the target oscillation source are identified as the generator set objects that need to be included in the initial set.

[0060] The preset sensitivity coefficient refers to a damping-power aggregation sensitivity coefficient pre-set for each oscillation mode. Its physical meaning is the improvement in the damping ratio of that mode by removing a unit of total negative oscillation power from the entire network. The initial value of this coefficient is set by technicians based on experience or historical system data, and the specific value is not limited in this application.

[0061] The predicted improvement refers to the expected increase in modal damping ratio after the removal of a specific unit or set of units, estimated using a linear prediction model. This predicted value is used to determine whether the current control action is sufficient to bring the modal damping ratio to a safe threshold.

[0062] In some embodiments of this application, the predicted improvement amount is calculated in the following manner:

[0063] In equation (4), j represents the unit number and j is a positive integer. This represents the preset sensitivity coefficient. This represents the absolute value of the negative oscillation power of unit j with respect to mode group m. This represents the absolute value of the negative oscillation power of unit j relative to mode group m. This value is derived from the net oscillation power across the frequency domain, i.e., the absolute value of the net oscillation power across the frequency domain is taken.

[0064] The preset search cutoff condition can refer to the criterion used to determine whether the currently selected set of generator units is sufficient to meet the system safety requirements. For example, the preset search cutoff condition can refer to the situation where, after prediction based on the currently selected set of generator units, the predicted damping ratio of all modes reaches or exceeds a preset damping safety threshold. Wherein, the predicted damping ratio... satisfy , This is the initial oscillation mode damping ratio.

[0065] The damping safety threshold is preset by technicians according to the requirements for stable operation of the power system, and the specific value is not limited in this application.

[0066] In response to the predicted improvement amount meeting the preset search cutoff condition, an initial set of units is generated based on the target units. That is, when the selected units make the predicted damping ratio meet the safety requirements of all modes, the addition of new units stops, and the set of currently selected target units is used as the initial set of units. This initial set of units is the starting point for subsequent iterative optimization searches.

[0067] S5 iteratively optimizes the initial set of units to generate the target set of units.

[0068] In some embodiments of this application, iterative optimization of the initial set of units to generate a target set of units includes: generating a neighborhood solution of the unit set based on the initial set of units; and iteratively optimizing the neighborhood solution of the unit set based on a preset optimization objective and a preset auxiliary objective to generate the target set of units.

[0069] Among them, the neighborhood solution of the unit set refers to the new candidate unit combination obtained by removing, replacing or adding units based on the current optimal unit set.

[0070] The preset optimization objective refers to the priority goal used to guide the iterative search process to converge in the desired direction. Its role is to minimize the economic cost of the final decision scheme while satisfying all modal damping constraints.

[0071] Preset auxiliary objectives refer to secondary objectives used to further screen and optimize solutions based on the achievement of the optimization objective. Their role is to enhance the robustness of the control strategy.

[0072] As a specific embodiment of this example, a forward greedy search method is first adopted. Starting from the top of the priority list, units are added to the temporary cut-off set sequentially. For each added unit, the damping ratio of all modes is quickly predicted using a linear prediction model until a set of units that satisfies the damping safety threshold of all modes is found as the initial feasible solution, i.e., the search starting point. Subsequently, an iterative optimization loop is executed within the allowed computation time window to improve the current optimal solution. Initially, the current optimal solution is the initial feasible solution. In each iteration, a neighborhood solution is generated based on the current optimal solution through three operations: first, attempting to remove units with lower power efficiency indices from the current optimal solution; second, attempting to replace one unit in the current optimal solution with another candidate unit in a similar position in the priority list; and third, attempting to add new units according to the priority list when the current optimal solution does not meet the constraints. For each new candidate solution, the predicted damping ratio of all modes is calculated using the prediction model, and only solutions that satisfy the global constraints are retained. Then, with constraints satisfied, the primary optimization objective is to minimize the total active power cut-off, while the secondary objective is to maximize the minimum damping margin to enhance the robustness of the solution. If a solution with a lower total cost or a larger minimum damping margin under the same cost is found, the current optimal solution is updated. Finally, after reaching the preset number of iterations or the emergency protection time limit, the current optimal solution is output as the final target unit set.

[0073] S6 issues a trip command to the target unit set to trip the target unit set.

[0074] For example, the master station system converts the target set of generating units into specific tripping commands, which include control parameters such as the identifiers of the units to be tripped, the tripping sequence, and the tripping power. These commands are then sent to the control systems deployed at each renewable energy plant or power generation unit via a dedicated control communication channel through the safety command closed-loop management unit. Upon receiving the command, the control system executes the corresponding circuit breaker tripping or unit disconnection operations according to the command requirements, completing the actual tripping of the target set of generating units.

[0075] In some embodiments of this application, after switching the target set of generators, the method further includes: obtaining the actual improvement of the power system, and updating the preset sensitivity coefficient based on the actual improvement and a preset update algorithm.

[0076] The actual improvement refers to the value obtained by continuously monitoring the actual change in the damping ratio of each oscillation mode after the generator tripping command is executed. For example, the measured damping ratio of each mode after tripping is compared with the corresponding initial damping ratio before tripping, and the difference between the two is calculated; this difference is the actual improvement. The actual improvement reflects the response effect of the real power system to the actual generator tripping action and is an important feedback information used to correct the prediction model.

[0077] A pre-set update algorithm refers to an algorithm used to adjust model parameters online based on the error between actual observations and predicted values, gradually approximating the characteristics of the real system. This algorithm can employ recursive least squares, the basic idea of ​​which is to update the pre-set sensitivity coefficients recursively for each new sample of actual improvement, so that the updated coefficients can better fit the historical and current data characteristics.

[0078] As a specific embodiment of this example, online learning algorithms such as recursive least squares are used to update the sensitivity coefficients. α m ,For example:

[0079] (5) In the formula, This represents the updated sensitivity coefficient. This represents the sensitivity coefficient before the update. Indicates the actual amount of improvement. Represents the target set of units. γ This represents the learning rate, which controls the size of the correction step during each update. A larger learning rate results in a stronger corrective effect of new data on the coefficients. This value is preset by technicians based on the system's response characteristics, and the specific value is not limited. λ This represents the forgetting factor, used to prevent the denominator from being too small and causing numerical instability. It can also adjust the degree of influence of historical data on the current coefficient. This value is preset by technicians according to the algorithm's stability requirements, and the specific value is not limited.

[0080] This application provides a novel emergency control method for multimodal broadband oscillations in power systems. The method first obtains oscillation source analysis results, calculates a comprehensive threat assessment index integrating divergence velocity, energy scale, and source dispersion, and selects the most critical target mode group from multiple negative damping mode groups. Then, it generates a candidate oscillation source set based on cross-frequency domain net oscillation power and preset screening conditions, calculates the power cut-off efficiency index, and sorts them in descending order to obtain an initial control priority list. Next, it uses a forward greedy search, combined with preset sensitivity coefficients and a linear prediction model, to generate an initial set of generating units that meet safety constraints. Then, it iteratively optimizes this set through three neighborhood operations: removal, replacement, and addition, with minimizing the total power cut-off as the primary objective and maximizing the minimum damping margin as the secondary objective, ultimately outputting the target set of generating units. Finally, it issues a tripping command to execute control, and uses the actual improvement amount to update the sensitivity coefficients online using a recursive least squares method, achieving adaptive correction of the prediction model.

[0081] As a specific embodiment of this application, refer to Figure 2 The emergency control method for multi-mode broadband oscillations in power systems in this application also includes: S201, obtain the oscillation source analysis results.

[0082] S202, construct a comprehensive threat assessment index that integrates diffusion speed, energy scale and propagation breadth.

[0083] S203, Select the target modal group based on the comprehensive threat assessment indicators.

[0084] S204 Calculate the cutoff power efficiency index of candidate oscillation sources and sort them by index size to form an initial control priority list.

[0085] S205, Initialize sensitivity coefficient.

[0086] S206 uses a preset search method to generate an initial set of units.

[0087] S207 generates a neighborhood solution for the unit set based on the current optimal solution through removal, replacement, and addition operations.

[0088] S208, determine whether the candidate solution can achieve a better preset optimization target or preset auxiliary target: if yes, execute S209; otherwise, execute S210.

[0089] S209, Update the current optimal solution.

[0090] S210, determine whether the iteration count or time limit has been reached: if yes, execute S211; otherwise, execute S207.

[0091] S211, take the current optimal solution as the target unit set.

[0092] S212 converts the target unit set into a trip command and issues it for execution.

[0093] S213 continuously monitors the actual changes in damping of each mode and updates the preset sensitivity coefficient.

[0094] The emergency control method for multimodal broadband oscillations in power systems proposed in this application has the following technical advantages compared to related technologies: 1. Multimodal threat comprehensive ranking capability. Automatically filters out the target mode group with the highest comprehensive threat from multiple concurrent oscillation modes, and prioritizes control resources to the oscillation mode with the greatest systemic risk.

[0095] 2. Rapid control performance evaluation capability. Candidate oscillation sources can be rapidly ranked using only locally measured cross-frequency domain net oscillation power and unit capacity, without the need to establish a precise full-system model, meeting the time requirements for second-level emergency control.

[0096] 3. Near-optimal economic control capability. A near-optimal tripping strategy is obtained within a finite computation time, satisfying the damping safety constraints of all modes with the minimum total tripping power cost, while maximizing the minimum damping margin to enhance the robustness of the control scheme.

[0097] 4. Online adaptive learning capability. Through an online learning mechanism, the sensitivity coefficient is continuously adjusted using actual damping change data after each switchover, enabling the prediction model to dynamically adapt to changes in system operation.

[0098] 5. Multimodal collaborative optimization capability. During the optimization process, the damping constraints of all modes are uniformly verified to ensure that the generated switching strategy will not deteriorate the stability of one mode by suppressing another.

[0099] Corresponding to the above embodiments, this application also provides an emergency control device for multi-mode broadband oscillations in a power system, referring to... Figure 3 The device 300 includes: an acquisition module 310, a filtering module 320, a first generation module 330, a second generation module 340, an optimization module 350, and a control module 360.

[0100] The acquisition module 310 is used to acquire the oscillation source analysis results of the power system and determine the target mode group based on the oscillation source analysis results. The oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of monitoring nodes for each mode group. The screening module 320 is used to screen the target mode group based on the cross-frequency domain net oscillation power and preset screening conditions to generate a candidate oscillation source set. The first generation module 330 is used to generate an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power. The second generation module 340 is used to generate an initial unit set based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list. The optimization module 350 is used to iteratively optimize the initial unit set to generate a target unit set. The control module 360 ​​is used to issue a tripping command to the target unit set to trip the target unit set.

[0101] In some embodiments of this application, the acquisition module 310 determines the target mode group based on the oscillation source analysis results, specifically used for: calculating the comprehensive threat assessment index of each mode group based on the oscillation source analysis results; and taking the mode group corresponding to the maximum value in the comprehensive threat assessment index as the target mode group.

[0102] In some embodiments of this application, the acquisition module 310 further determines the oscillation source analysis results by including the mode group damping ratio and the total number of monitoring nodes. The comprehensive threat assessment index is calculated in the following way:

[0103] Where m represents the index of the mode group, and m is a positive integer. This represents the absolute value of the modal group damping ratio of modal group m. This represents the number of nodes in mode group m whose net oscillation power across the frequency domain is negative. S This indicates the total number of monitoring nodes.

[0104] In some embodiments of this application, the first generation module 330 generates an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power. Specifically, it is used to: calculate the cut-off power efficiency index of the candidate oscillation sources in the candidate oscillation source set based on the cross-frequency domain net oscillation power; and sort the candidate oscillation sources in descending order based on the cut-off power efficiency index to generate the initial control priority list.

[0105] In some embodiments of this application, the first generation module 330 determines that the cut-off power efficiency index is calculated in the following manner:

[0106] Where j represents the index of the candidate oscillation source and j is a positive integer. This represents the active power capacity of candidate oscillation source j. This represents the net oscillation power across the frequency domain of candidate oscillation source j.

[0107] In some embodiments of this application, the second generation module 340 determines that the power system includes multiple generating units. Specifically, the generation of an initial generating unit set based on a preset search method, a preset sensitivity coefficient, cross-frequency domain net oscillation power, and an initial control priority list is used to: search for candidate oscillation sources in the initial control priority list based on the preset search method to determine the target oscillation source, and take the generating unit corresponding to the target oscillation source as the initial generating unit; calculate the predicted improvement amount of the target generating unit based on the preset sensitivity coefficient and cross-frequency domain net oscillation power; and generate the initial generating unit set based on the target generating unit in response to the predicted improvement amount satisfying the preset search cutoff condition.

[0108] In some embodiments of this application, the second generation module 340 determines the predicted improvement amount by calculating it in the following manner:

[0109] Where j represents the unit number and j is a positive integer. This represents the preset sensitivity coefficient. This represents the absolute value of the negative oscillation power of unit j with respect to mode group m. It is derived from the net oscillation power across the frequency domain.

[0110] In some embodiments of this application, the optimization module 350 iteratively optimizes the initial set of units to generate a target set of units, specifically for: generating a neighborhood solution of the unit set based on the initial set of units; and iteratively optimizing the neighborhood solution of the unit set based on a preset optimization target and a preset auxiliary target to generate the target set of units.

[0111] In some embodiments of this application, after the control module 360 ​​switches the target generator set, it further includes: obtaining the actual improvement amount of the power system, and updating the preset sensitivity coefficient based on the actual improvement amount and the preset update algorithm.

[0112] It is understood that for details not disclosed in the above-described embodiment of the multi-mode broadband oscillation emergency control device for power systems, please refer to the details disclosed in the embodiment of the multi-mode broadband oscillation emergency control method for power systems.

[0113] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0114] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0115] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0116] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0117] Any process or method described in the flowchart or otherwise herein is to be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0118] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0119] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0120] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it includes one or a combination of the steps of the method embodiments.

[0121] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0122] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

[0123] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0124] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for emergency control of multi-mode broadband oscillations in a power system, characterized in that, include: Obtain the oscillation source analysis results of the power system, and determine the target mode group based on the oscillation source analysis results, wherein the oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of the monitoring node for each mode group; The target mode group is screened based on the cross-frequency domain net oscillation power and preset screening conditions to generate a candidate oscillation source set; An initial control priority list is generated based on the candidate oscillation source set and the cross-frequency domain net oscillation power. An initial set of generator units is generated based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list. The initial set of generating units is iteratively optimized to generate the target set of generating units; A trip command is issued to the target set of units to trip the target set of units.

2. The method according to claim 1, characterized in that, The determination of the target mode group based on the oscillation source analysis results includes: Based on the oscillation source analysis results, a comprehensive threat assessment index for each of the modal groups is calculated. The modality group corresponding to the maximum value in the comprehensive threat assessment index is taken as the target modality group.

3. The method according to claim 2, characterized in that, The oscillation source analysis results also include the mode group damping ratio and the total number of monitoring nodes. The comprehensive threat assessment index is calculated in the following way: Where m represents the index of the mode group, and m is a positive integer. The absolute value of the mode group damping ratio of mode group m is given. This represents the number of nodes in mode group m whose cross-frequency domain net oscillation power is negative. S Indicates the total number of monitoring nodes. This represents the absolute value of the net oscillation power across the frequency domain of mode group m.

4. The method according to claim 1, characterized in that, The generation of the initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power includes: The power efficiency index of the cut-off of candidate oscillation sources in the candidate oscillation source set is calculated based on the cross-frequency domain net oscillation power. The candidate oscillation sources are sorted in descending order based on the cutoff power efficiency index to generate the initial control priority list.

5. The method according to claim 4, characterized in that, The resection power efficiency index is calculated in the following way: Where j represents the index of the candidate oscillation source and j is a positive integer. This represents the active power capacity of candidate oscillation source j. The term "cross-frequency domain net oscillation power" represents the value of candidate oscillation source j.

6. The method according to claim 1, characterized in that, The power system includes multiple generating units, wherein the generation of the initial generating unit set based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list includes: The candidate oscillation sources in the initial control priority list are searched based on the preset search method to determine the target oscillation source, and the unit corresponding to the target oscillation source is taken as the initial unit; The predicted improvement of the target unit is calculated based on the preset sensitivity coefficient and the cross-frequency domain net oscillation power. In response to the predicted improvement amount satisfying the preset search cutoff condition, the initial set of units is generated based on the target units.

7. The method according to claim 6, characterized in that, The predicted improvement amount is calculated in the following way: Where j represents the unit number and j is a positive integer. This represents the preset sensitivity coefficient. This represents the absolute value of the negative oscillation power of unit j with respect to mode group m. It is derived from the aforementioned cross-frequency domain net oscillation power.

8. The method according to claim 1, characterized in that, The iterative optimization of the initial set of units to generate the target set of units includes: Generate a neighborhood solution for the unit set based on the initial unit set; The neighborhood solution of the unit set is iteratively optimized based on the preset optimization objective and the preset auxiliary objective to generate the target unit set.

9. The method according to claim 1, characterized in that, After switching the target unit set, the process further includes: The actual improvement in the power system is obtained, and the preset sensitivity coefficient is updated based on the actual improvement and the preset update algorithm.

10. A multi-mode broadband oscillation emergency control device for a power system, characterized in that, include: An acquisition module is used to acquire the oscillation source analysis results of the power system and determine the target mode group based on the oscillation source analysis results, wherein the oscillation source analysis results include multiple mode groups and the cross-frequency domain net oscillation power of the monitoring node for each mode group; The filtering module is used to filter the target mode group based on the cross-frequency domain net oscillation power and preset filtering conditions to generate a candidate oscillation source set; The first generation module is used to generate an initial control priority list based on the candidate oscillation source set and the cross-frequency domain net oscillation power. The second generation module is used to generate an initial set of generator units based on a preset search method, a preset sensitivity coefficient, the cross-frequency domain net oscillation power, and the initial control priority list. An optimization module is used to iteratively optimize the initial set of units to generate a target set of units; The control module is used to issue a switchover command to the target set of units in order to switch over the target set of units.

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