A power system active splitting section search method, system and electronic equipment

Abstract

The application discloses a power system active splitting section searching method and system and electronic equipment, and relates to the technical field of power system safety and power system emergency control. The application firstly takes the minimum sum of the line flow before the disturbance is disconnected as a target function, considers the basic operation constraints followed by the power system to ensure the connectivity of the internal island after splitting and the non-connecting path between different islands; then, a mixed integer second-order cone programming model is constructed based on the target function and the basic operation constraints of the active splitting, the requirement of reactive power balance and voltage of the island after splitting can be considered, and the optimal splitting section meeting the stable operation of the power system is obtained. On this basis, the system frequency minimum point constraint is introduced to balance the frequency modulation resources, so that the frequency stability of each island is better ensured.

Description

Technical Field

[0001] This invention relates to the fields of power system safety technology and power system emergency control technology, and in particular to a method, system and electronic equipment for searching active disconnection sections in a power system. Background Technology

[0002] As power system structures become increasingly complex, the risk of failures under extreme weather conditions is becoming more significant. A serious fault in a fragile grid structure could trigger a cascading failure, leading to power system collapse. Active disconnection is considered the last line of defense against grid collapse. If the system can be rationally divided into several stable islands, large-scale blackouts can be largely prevented.

[0003] Active disconnection requires consideration of three main issues: whether to disconnect, where to disconnect, and how to disconnect. Among these, the question of where to disconnect, i.e., cross-section search, is a hot topic and key focus in active disconnection problems. Currently, commonly used methods include heuristic and mathematical programming optimization methods. Mathematical programming methods have been widely applied in recent years because they overcome the shortcomings of heuristic methods, such as poor robustness and the low probability of obtaining the global optimum. However, these studies often employ approximate DC power flow models to obtain efficiently solvable mixed-integer linear programming models, failing to consider critical requirements such as system voltage in the disconnection optimization model.

[0004] Active disconnection optimization models often aim to minimize load shedding, power flow impact, or active power imbalance, using high-inertia synchronous generator synchronization as a constraint to maintain islanded power angle stability. With the high proportion of wind power, photovoltaic, and other new energy units connected to the grid, if the majority of units on the island after disconnection are low-inertia new energy units, the island is easily disturbed and experiences frequency instability, which can lead to the island going completely "black". Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method, system, and electronic device for actively disconnecting power system sections.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for actively disconnecting power system sections includes:

[0008] The coherent generator units are obtained by using coherence identification technology to acquire the grouping information of each generator in the power system.

[0009] The generators in the synchronized generator set that meet the preset conditions are designated as synchronized generators, and the other generators besides the synchronized generators are designated as generators whose ownership is not determined.

[0010] Using the largest coherent generator in each coherent generator group as the root node of the island, the generators whose affiliation is not determined are divided into islands according to the constraint of the lowest frequency point to obtain a preliminary generator group set.

[0011] A mixed-integer second-order cone programming model is constructed based on the objective function of active disconnection and basic operational constraints; the basic operational constraints include: network connectivity constraints and power system physical operational constraints; wherein, the objective function is to minimize the total power flow of the line before disconnection from the disturbance.

[0012] Collect power flow information before power system is disturbed and operational data after instability;

[0013] The mixed-integer second-order cone programming model is used to determine the final generator cluster set and the optimal solution section based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability.

[0014] Optionally, the generators in the synchronized unit that meet preset conditions are designated as synchronized generators, specifically including:

[0015] The generators in each synchronized unit are sorted according to their output power to obtain the generator sequence;

[0016] And at least 20% of the generators preceding the generator sequence are designated as co-tuning generators.

[0017] Optionally, the largest coherent generator in each coherent generator group is used as the root node of the island. Based on the minimum frequency constraint, the unassigned generators are divided into islands to obtain a preliminary generator group set, specifically including:

[0018] Treat each generator with an undetermined affiliation as a generator node, and determine the relationship between the i-th generator node and the root node r. k When all islands belong to the k-th island, the first condition is met; the first condition is:

[0019]

[0020]

[0021] The synchronized generator groups assigned to various isolated islands and the generators whose affiliation has not been determined satisfy the second condition; the second condition is:

[0022]

[0023] In the formula: V Gk Let R be the set of generators in the synchronized cluster of the k-th island, R be the set of all root nodes r, ω0 be the initial frequency of the island, and c be the frequency of the island. iLet z be the power ramp-up rate at generator node i during a single frequency regulation period. i,r Since generator node i and root node r both belong to the island, S g J is the set of generator nodes. i Let P be the moment of inertia of the rotor at the i-th generator node. loss,r K represents the expected power loss of the island containing the root node r. L Let ω be the load damping constant. min This is the minimum frequency for an isolated island.

[0024] Optionally, the objective function for the active unblocking is:

[0025]

[0026] In the formula, F is the objective function value, L is the set of lines in the power system, and l is the line number; d l Let d be a variable between 0 and 1, and when line l is disconnected... l Set to 0, when line l is not disconnected. l Take 1; λ is a constant, R ij P is the first auxiliary variable for branch ij in cone programming. l It is the average of the absolute values ​​of the active power in both directions of line l.

[0027] Optionally, the network connectivity constraint is:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033] In the formula, δ(i) is the set of all lines connected to generator node i, V is the set of all nodes in the power system, and f l,r z is the network flow variable between line l and root node r. i,r Let generator node i and root node r both belong to the island, R be the set of all root nodes r, δ(r) be the set of all lines connected to root node r, and y l,r When y ∈{0,1}, line l belongs to the root node r l,r When y is 1, and line l does not belong to the root node r. l,r Let |V| be 0, |V| represent the number of nodes in the set V of all nodes, L be the set of lines in the power system, δ(v) represent the set of all lines connected to generator node v, and zv,r The generator node v and the root node r both belong to the island.

[0034] Optionally, the physical operating constraints of the power system are:

[0035]

[0036]

[0037]

[0038] In the formula, Let be the upper limit of the active power output of generator node i. P is the lower limit of the active power output of generator node i. gi Let i be the active power output of generator node i. Let i be the upper limit of reactive power output of generator node i. Q is the lower limit of the reactive power output of generator node i. gi Let θ be the reactive power output of generator node i. ref Let θ be the phase angle of the reference node ref, {ref} be the set of all reference nodes, V be the set of all nodes in the power system, and θ be the phase angle of the reference node ref. i Let g be the phase angle of generator node i. ij Let b be the conductance of branch ij. ij For the susceptance of branch ij, For the ground susceptance of branch ij, u i l u is an auxiliary variable for node i corresponding to the l-th branch. j l F is an auxiliary variable for node j corresponding to the l-th branch. ij R is the second auxiliary variable for branch ij in cone programming. ij Let be the first auxiliary variable for branch ij in the cone programming problem. Branch ij is the branch from generator node i to generator node j. Let be the upper limit of the current in branch ij. Let be the upper limit of the voltage at generator node i. U i u is the lower limit of the voltage at generator node i. i Let L be the auxiliary variable for generator node i, and L be the set of lines in the power system.

[0039] Optionally, the mixed-integer second-order cone programming model is:

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046] In the formula: P gi P represents the active power output of generator node i. di P represents the active load at generator node i. ij L is the power of branch ij. i Let Q be the set of the other endpoints of the branch connected to generator node i. gi Q is the reactive power output of generator node i. di Q represents the reactive load at generator node i. ij Let R be the reactive power of branch ij, V be the set of all nodes in the power system, and R be the reactive power of branch ij. ij R is the first auxiliary variable for branch ij in cone programming. ji F is the first auxiliary variable for branch ji in cone programming. ij F is the second auxiliary variable for branch ij in cone programming. ji Let be the second auxiliary variable for branch ji in cone programming, and L be the set of lines in the power system. Let be the upper limit of the voltage at generator node i. d is the upper limit of the voltage at generator node j. l Let d be a variable between 0 and 1, and when line l is disconnected... l Set to 0, when line l is not disconnected. l Take 1;u i l u is an auxiliary variable for node i corresponding to the l-th branch. j l u is an auxiliary variable for node j corresponding to the l-th branch. i u is an auxiliary variable for generator node i. j θ is an auxiliary variable for generator node j. ij Let θ be the phase angle difference between generator node i and generator node j. i Let θ be the phase angle of generator node i. j Let g be the phase angle of generator node j. ij Let b be the conductance of branch ij. ij For the susceptance of branch ij, Let be the susceptance to ground of branch ij, where branch ij is the branch from generator node i to generator node j.

[0047] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0048] The active disconnection section search method for power systems provided by this invention first uses minimizing the total power flow of the lines before disconnection as the objective function, considering the basic operating constraints followed by the power system to ensure connectivity within the islands after disconnection and to ensure no connecting paths between different islands. Then, based on the objective function of active disconnection and the basic operating constraints, a mixed-integer second-order cone programming model is constructed, which can consider the reactive power balance and voltage requirements of the islands after disconnection, obtaining the optimal disconnection section that satisfies the stable operation of the power system. Furthermore, a constraint on the lowest system frequency point is introduced to evenly allocate frequency regulation resources, thereby better ensuring the frequency stability of each island.

[0049] Corresponding to the methods provided above, the present invention also provides the following implementation structures:

[0050] A power system active disconnection section search system, applied to the power system active disconnection section search method provided above; the system includes:

[0051] The cluster information acquisition module is used to obtain the cluster information of each generator in the power system using the coherence identification technology to obtain the coherent generator units.

[0052] The generator classification module is used to classify generators that meet preset conditions in the co-tuning unit as co-tuning generators, and to classify other generators besides the co-tuning generators as generators whose ownership has not been determined.

[0053] The initial cluster set determination module is used to divide the unassigned generators into islands based on the lowest frequency point constraint, taking the largest coherent generator in each coherent generator group as the root node of the island.

[0054] The second-order cone programming model construction module is used to construct a mixed-integer second-order cone programming model based on the objective function of active unblocking and basic operational constraints; the basic operational constraints include: network connectivity constraints and power system physical operational constraints; wherein, the objective function is to minimize the total power flow of the line before disconnection from the disturbance.

[0055] The power flow-operation data acquisition module is used to collect power flow information before the power system is disturbed and operation data after instability.

[0056] The clustering-disconnection section determination module is used to determine the final generator cluster set and the optimal disconnection section based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability using the mixed integer second-order cone programming model.

[0057] An electronic device, comprising:

[0058] Memory, used to store computer programs;

[0059] A processor, connected to the memory, is used to retrieve and execute the computer program to implement the power system active disconnection section search method provided above.

[0060] Optionally, the memory is a computer-readable storage medium.

[0061] Since the technical effects achieved by the two implementation structures provided above in this invention are the same as those achieved by the power system active disconnection section search method provided in this invention, they will not be described again here. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 A flowchart of the active disconnection section search method for power systems provided by the present invention;

[0064] Figure 2 This is a diagram of the islanding structure of the IEEE 118-node system used in the experiment of this invention;

[0065] Figure 3 This is a diagram of the IEEE 118-node island structure considered for frequency stability in the experiments of this invention;

[0066] Figure 4 This is a graph showing the frequency variation of each island in the IEEE 118 node after considering frequency stability in the experiment of this invention. Detailed Implementation

[0067] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] The purpose of this invention is to provide a method, system, and electronic equipment for actively disconnecting power systems, which can rationally determine the distribution of large-inertia synchronous generators in each isolated island, thereby solving the problem of completely "black" islands in the existing technology.

[0069] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0070] The overall concept of this invention is as follows: Aiming to minimize the power flow before the disturbance is disconnected, the distribution of each islanded generator is rationally determined by using the lowest islanded frequency constraint, taking into account the differences in the rotational inertia of each synchronous generator and the speed regulation rate of the governor. A series of linear constraints are used to ensure connectivity within each island and that there are no connecting paths between different islands. The reactive power balance and voltage requirements of the islands after decoupling are also considered, making the decoupling system more operationally feasible.

[0071] Based on this, the present invention provides a method for actively disconnecting power system sections, such as... Figure 1 As shown, the method includes:

[0072] Step 100: Use the coherence identification technology to obtain the grouping information of each generator in the power system to obtain the coherent generator units.

[0073] Step 101: Designate generators in the synchronized generator group that meet the preset conditions as synchronized generators, and designate other generators as generators with undetermined affiliation. For example, select the generators with the highest output power in each subgroup and retain them as synchronized generators in that group. The proportion of these generators in the original synchronized generator group should be less than 20%, while the remaining generators in the group are regarded as generator nodes with undetermined affiliation.

[0074] Step 102: Using the largest co-tuning generator in each co-tuning group as the root node of the island, divide the unassigned generators into islands according to the minimum frequency constraint to obtain a preliminary generator group set. In this step, it is assumed that the islands may be affected by power deficits. Based on the minimum frequency constraint, each unassigned generator is assigned to a certain island, obtaining some preliminary generator group sets. Specifically:

[0075] The generator with the largest capacity among the obtained coherent generator groups is selected as the root node r of the island. Assume the system has m coherent generator groups and is divided into m islands. Definition Is the i-th generator node related to the root node r? k If they belong to the k-th island, they satisfy:

[0076]

[0077]

[0078] The synchronized generator groups and unassigned generators assigned to various isolated islands satisfy the following:

[0079]

[0080] In the formula: V Gk Let R be the set of generators in the synchronized cluster of the k-th island, R be the set of all root nodes r, ω0 be the initial frequency of the island, and c be the frequency of the island. i Let z be the power ramp-up rate at generator node i during a single frequency regulation period. i,r To determine whether generator node i and root node r both belong to an island, S g J is the set of generator nodes. i Let P be the moment of inertia of the rotor at the i-th generator node. loss,r K represents the expected power loss of the island containing the root node r. L Let ω be the load damping constant. min This is the minimum frequency of the isolated island. Where ω min P can be set by the maximum threshold for low-frequency load shedding. loss,r Offline assessments can be performed based on the maximum generator capacity within the isolated island or the power loss caused by line outages.

[0081] Step 103: Construct a mixed-integer second-order cone programming model based on the objective function of active disconnection and the basic operational constraints. The basic operational constraints include network connectivity constraints and power system physical operational constraints. The objective function is to minimize the total power flow of the lines before the disturbance is disconnected.

[0082] In this step, the objective function for active unpacking is:

[0083]

[0084] In the formula, F is the objective function value, L is the set of lines in the power system, and l is the line number. l Let d be a variable between 0 and 1, and when line l is disconnected... l Set to 0, when line l is not disconnected. l Let λ be 1. λ is a constant, and R... ij P is the first auxiliary variable for branch ij in cone programming. l This is the average of the absolute values ​​of the active power in both directions of line l. That is:

[0085] Where, p ij To determine the active power in the positive direction of line ij before disconnection, p ji This refers to the active power in the negative direction of line ij before disconnection.

[0086] The entire power system is divided into m islands, and generators with undetermined affiliations are assigned to different islands. For each line l∈L, a set of network flow variables f is used. l,rLet represent the size of the network flow from line l to root node r. Then the network connectivity constraint is:

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093] In the formula, δ(i) is the set of all lines connected to generator node i, V is the set of all nodes in the power system, and f l,r z is the network flow variable between line l and root node r. i,r Let generator node i and root node r both belong to the island, δ(r) be the set of all lines connected to root node r, and y l,r When y ∈{0,1}, line l belongs to the root node r l,r When y is 1, and line l does not belong to the root node r. l,r The value is 0, |V| represents the number of nodes in the set V of all nodes, δ(v) represents the set of all lines connected to generator node v, and z v,r The generator node v and the root node r both belong to the island.

[0094] The physical operating constraints of the power system are:

[0095]

[0096]

[0097]

[0098] In the formula, Let be the upper limit of the active power output of generator node i. P is the lower limit of the active power output of generator node i. gi Let i be the active power output of generator node i. Let i be the upper limit of reactive power output of generator node i. Q is the lower limit of the reactive power output of generator node i. gi Let θ be the reactive power output of generator node i. ref Let θ be the phase angle of the reference node ref, and {ref} be the set of all reference nodes. i Let g be the phase angle of generator node i. ijLet b be the conductance of branch ij. ij For the susceptance of branch ij, For the ground susceptance of branch ij, u i l u is an auxiliary variable for node i corresponding to the l-th branch. j l F is an auxiliary variable for node j corresponding to the l-th branch. ij Let be the second auxiliary variable for branch ij in the cone programming problem. Branch ij is the branch from generator node i to generator node j. Let be the upper limit of the current in branch ij. Let be the upper limit of the voltage at generator node i. U i u is the lower limit of the voltage at generator node i. i This is an auxiliary variable for generator node i.

[0099] Based on the objective function and basic operating constraints given above, the mixed-integer second-order cone programming model (i.e., the second-order cone relaxation of the power flow equations) is constructed as follows:

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] In the formula: P di P represents the active load at generator node i. ij L is the power of branch ij. i Let Q be the set of the other endpoints of the branch connected to generator node i. di Q represents the reactive load at generator node i. ij R is the reactive power of branch ij. ji F is the first auxiliary variable for branch ji in cone programming. ji As the second auxiliary variable for branch ji in cone programming, u is the upper limit of the voltage at generator node j. j l u is an auxiliary variable for node j corresponding to the l-th branch. j θ is an auxiliary variable for generator node j. ij Let θ be the phase angle difference between generator node i and generator node j. jLet be the phase angle of generator node j.

[0107] Step 104: Collect power flow information before the power system is disturbed and operational data after instability.

[0108] Step 105: Using a mixed-integer second-order cone programming model, determine the final generator cluster set and the optimal solution section based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability.

[0109] The following experiments further illustrate the specific implementation process and advantages of the power system active disconnection section search method provided by the present invention.

[0110] To demonstrate that the proposed active disconnection section search method for power systems can obtain relatively stable islands, this experiment first verifies whether the expected clustering can be achieved through the IEEE 118-node system. The IEEE 118-node system contains 118 nodes, 186 lines, and 19 synchronous generators, with a base capacity of 100MW and a maximum line current of 5.0pu.

[0111] Ignoring the minimum frequency constraint for now, the solved system is divided into three islands, A, B, and C, as follows: Figure 2 As shown, Figure 2 The squares represent generator nodes, the dots represent other (load) nodes, and the dashed lines represent disconnection sections. It can be seen that the system is disconnected into three islands as expected, with nodes within each island interconnected.

[0112] To demonstrate the impact of reactive power and voltage requirements on the disconnection strategy, a 50 Mvar reactive load was added to node 4 of the IEEE 118-node system. The maximum current for lines 8-9 and 26-30 was set to 2.60 pu, while the maximum current for other lines was 5.0 pu. Voltage constraints for all nodes were set to 0.95–1.05 pu, and the system was solved. Table 1 shows the changes in the system disconnection profile.

[0113] Table 1 Comparison of the disengagement profiles of the IEEE 118-node system

[0114]

[0115]

[0116] Due to the increased reactive load, the power of line 8-9 in the islanded system is 226.53MW. While this does not exceed the limit when considering only active power, the increased reactive load leads to a higher reactive power transmitted through the line, causing the current to exceed the maximum allowable current. By changing the cross-sections from lines 24-70 and 24-72 to line 23-24, the optimized current of line 8-9 in the islanded system is 2.55pu, which does not exceed the limit. This demonstrates that the present invention, by considering both reactive power and voltage requirements, is more practical.

[0117] Modifications were made to the IEEE 118-node system, replacing the generators at nodes 25, 31, 46, 59, and 103 with doubly-fed wind turbines of the same output. Therefore, without considering the minimum frequency constraint, the resulting cross-section and topology after replacing the wind turbines remain consistent with... Figure 2 Consistent. Assuming these wind turbines lack primary frequency regulation capability, let the three co-regulating turbine groups be {10,12}, {49,54}, and {87,89}, while the other synchronous generators have weaker co-regulation. The system's rated frequency is 60Hz, and the minimum preset frequency value is 59.4Hz. For ease of analysis, assume the anticipated power deficit for each island is 80MW.

[0118] After considering the minimum frequency constraint calculation, the three isolated islands after demultiplexing are as follows: Figure 3 As shown. With Figure 2 In comparison, the islanding profile has changed. Island A, in order to meet frequency constraints, has expanded its scale and added some synchronous generators. Island B, compared to... Figure 3 Although the scale has been reduced, the frequency requirements are still met due to the sufficient number of synchronous generators. This demonstrates that the minimum frequency constraint plays a role in balancing the frequency regulation resources of the isolated synchronous generators, thus contributing to frequency stability.

[0119] Figure 4 The table shows the frequency changes of each island after the disturbance. Table 2 compares the active disconnection model with and without frequency constraints. It can be seen that without considering the minimum frequency constraint, the minimum frequency (f) of the generator in island A, which has fewer frequency regulation resources, will drop to 59.12Hz, significantly deviating from the safe frequency range. However, with the constraint considered, the system frequency in island A increases to 59.4Hz, remaining within the safe range. This demonstrates that the method proposed in this invention improves the system's ability to maintain frequency stability and enhances the resilience of the islands. Figure 4 In this context, t represents time.

[0120] Table 2 Comparison of the lowest frequency points of generators in different isolated islands

[0121]

[0122] Based on the above description, the power system active disconnection section search method provided by the present invention has the following advantages compared with the prior art:

[0123] 1) This invention proposes a hybrid integer second-order cone programming model for active islanding, which can take into account the reactive power balance and voltage requirements of the islanded islands after islanding.

[0124] 2) This invention takes into account the high penetration rate of new energy sources in the power system and the susceptibility to power shortage disturbances, and rationally allocates each large-inertia synchronous generator to each island, so that each island can maintain frequency stability.

[0125] Corresponding to the methods provided above, the present invention also provides the following implementation structures:

[0126] A power system active disconnection section search system is provided, applied to the power system active disconnection section search method provided above. The system includes:

[0127] The cluster information acquisition module is used to obtain the cluster information of each generator in the power system using the coherence identification technology to obtain the coherent generator units.

[0128] The generator classification module is used to classify generators that meet preset conditions in the coordinating unit as coordinating generators, and to classify other generators besides coordinating generators as generators with undetermined affiliation.

[0129] The initial cluster set determination module is used to divide the unassigned generators into islands based on the lowest frequency point constraint, using the largest coherent generator in each coherent generator group as the root node of the island.

[0130] The second-order cone programming model construction module is used to construct a mixed-integer second-order cone programming model based on the objective function of active disconnection and basic operational constraints. The basic operational constraints include network connectivity constraints and power system physical operational constraints. The objective function is to minimize the total power flow of the lines before the disturbance is disconnected.

[0131] The power flow-operation data acquisition module is used to collect power flow information before the power system is disturbed and operation data after instability.

[0132] The clustering-disconnection profile determination module is used to determine the final generator cluster set and the optimal disconnection profile based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability using a mixed integer second-order cone programming model.

[0133] An electronic device, comprising:

[0134] Memory is used to store computer programs.

[0135] A processor, connected to a memory, is used to retrieve and execute a computer program to implement the power system active disconnection section search method provided above.

[0136] Furthermore, when the computer program in the aforementioned memory is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0137] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0138] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for actively disconnecting power system sections, characterized in that, include: The coherent generator units are obtained by using coherence identification technology to acquire the grouping information of each generator in the power system. The generators in the synchronized generator set that meet the preset conditions are designated as synchronized generators, and the other generators besides the synchronized generators are designated as generators whose ownership is not determined. Using the largest coherent generator in each coherent generator group as the root node of the island, the generators whose affiliation is not determined are divided into islands according to the constraint of the lowest frequency point to obtain a preliminary generator group set. A mixed-integer second-order cone programming model is constructed based on the objective function of active unblocking and the basic operational constraints. The basic operational constraints include: network connectivity constraints and power system physical operational constraints; among which, minimizing the total power flow of the line before the disturbance is disconnected is taken as the objective function; Collect power flow information before power system is disturbed and operational data after instability; The mixed-integer second-order cone programming model is used to determine the final generator cluster set and the optimal solution section based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability.

2. The power system active disconnection section search method according to claim 1, characterized in that, The generators in the synchronized generator set that meet the preset conditions are designated as synchronized generators, specifically including: The generators in each synchronized unit are sorted according to their output power to obtain the generator sequence; And at least 20% of the generators in the generator sequence are designated as co-tuning generators.

3. The power system active disconnection section search method according to claim 1, characterized in that, Using the largest coherent generator in each coherent generator group as the root node of the island, and based on the minimum frequency constraint, the unassigned generators are divided into islands to obtain a preliminary generator group set, specifically including: Each generator with an undetermined affiliation is treated as a generator node, and the first... Each generator node and the root node Belonging to the first When there is an isolated island, the first condition is met; the first condition is: ； ； The synchronized generator groups assigned to various isolated islands and the generators whose affiliation has not been determined satisfy the second condition; the second condition is: ； In the formula: For the first A collection of generators in a synchronized machine group on an isolated island. For all root nodes The set, The initial frequency of the isolated island. For generator nodes during a single frequency regulation period i Output power ramp-up rate, For generator nodes With the root node Both belong to isolated islands, For the set of generator nodes, For the first The moment of inertia of the rotor at each generator node. root node The anticipated power loss on the isolated island. Let be the load damping constant. The minimum frequency for an isolated island. For the first Are the generator nodes related to the root node? Belonging to the first A deserted island, m This represents the number of isolated islands.

4. The power system active disconnection section search method according to claim 1, characterized in that, The network connectivity constraint is: ； ； ； ； ； ； In the formula, To connect to the generator node All lines It is the set of all nodes in the power system. For the line With the root node Network flow variables between For generator nodes With the root node Both belong to isolated islands, For all root nodes The set, To connect to the root node All lines ,line Belongs to the root node hour The line is 1. Not a root node hour =0, Represents the set of all nodes The number of nodes in the middle, A collection of lines in a power system. Indicates connection to generator node All lines For generator nodes With the root node Both belong to isolated islands, For a variable between 0 and 1, when the line When disconnected Take 0, when the line When not disconnected Take 1.

5. The power system active disconnection section search method according to claim 1, characterized in that, The physical operating constraints of the power system are: ； ； ； In the formula, For generator nodes i The upper limit of effective output, For generator nodes i The lower limit of meritorious contribution, For generator nodes i Those who have made contributions For generator nodes i The upper limit of reactive power output, For generator nodes i The lower limit of no-efficiency output, For generator nodes i Unproductive efforts Reference node phase angle, For the set of all reference nodes, It is the set of all nodes in the power system. For generator nodes i phase angle, branch road electrical conductivity, branch road susceptivity, branch road The susceptibility to ground, For the first The nodes corresponding to each branch Auxiliary variables, For the first The nodes corresponding to each branch j Auxiliary variables, Branch roads in cone planning The second auxiliary variable, Branch roads in cone planning The first auxiliary variable, branch For generator node i To generator node j The side road, branch road The upper limit of current, For generator nodes i The upper limit of voltage, For generator nodes i The lower limit of voltage, For generator nodes i Auxiliary variables, It refers to the set of lines in a power system.

6. The power system active disconnection section search method according to claim 1, characterized in that, The mixed-integer second-order cone programming model is as follows: ； ； ； ； ； ； In the formula: For generator nodes i Those who have made contributions For generator nodes i Active load, branch road power, To connect with generator nodes i The set of the other endpoints corresponding to the connected branches. For generator nodes i Unproductive efforts For generator nodes i reactive load, branch road reactive power, It is the set of all nodes in the power system. Branch roads in cone planning The first auxiliary variable, Branch roads in cone planning The first auxiliary variable, Branch roads in cone planning The second auxiliary variable, Branch roads in cone planning The second auxiliary variable, A collection of lines in a power system. For generator nodes i The upper limit of voltage, For generator nodes j The upper limit of voltage, For a variable between 0 and 1, when the line When disconnected Take 0, when the line When not disconnected Take 1; For the first The nodes corresponding to each branch Auxiliary variables, For the first The nodes corresponding to each branch j Auxiliary variables, For generator nodes i Auxiliary variables, For generator nodes j Auxiliary variables, For generator nodes and generator node The phase angle difference between them For generator nodes i phase angle, For generator nodes j phase angle, branch road electrical conductivity, branch road susceptivity, branch road ground susceptance, branch For generator node i To generator node j A side road.

7. A power system active disconnection section search system, characterized in that, The system is applied to the power system active disconnection section search method as described in any one of claims 1-6; the system includes: The cluster information acquisition module is used to obtain the cluster information of each generator in the power system using the coherence identification technology to obtain the coherent generator units. The generator classification module is used to classify generators that meet preset conditions in the co-tuning unit as co-tuning generators, and to classify other generators besides the co-tuning generators as generators whose ownership has not been determined. The initial cluster set determination module is used to divide the unassigned generators into islands based on the lowest frequency point constraint, taking the largest coherent generator in each coherent generator group as the root node of the island. The second-order cone programming model construction module is used to construct a mixed-integer second-order cone programming model based on the objective function of active unblocking and basic operational constraints; the basic operational constraints include: network connectivity constraints and power system physical operational constraints; wherein, the objective function is to minimize the total power flow of the line before disconnection from the disturbance. The power flow-operation data acquisition module is used to collect power flow information before the power system is disturbed and operation data after instability. The clustering-disconnection section determination module is used to determine the final generator cluster set and the optimal disconnection section based on the power flow information before the power system is disturbed, the preliminary generator cluster set, and the operating data after instability using the mixed integer second-order cone programming model.

8. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, connected to the memory, is configured to retrieve and execute the computer program to implement the power system active disconnection section search method as described in any one of claims 1-6.

9. The electronic device according to claim 8, characterized in that, The memory is a computer-readable storage medium.

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