Power grid synchronization instability high-risk disturbance set dynamic selection method and device, equipment and medium

Abstract

The invention discloses a power grid synchronization instability high-risk disturbance set dynamic selection method and device, equipment and a medium. The method comprises the steps of obtaining a power grid topology generated by a power grid planning model; searching the power grid topology by adopting a long-chain power transmission channel searching method to obtain a long-chain power transmission channel set; and a high-risk disturbance set selection method based on a channel electrical distance index is adopted to screen the long-chain power transmission channel set so as to dynamically obtain a synchronous instability high-risk disturbance set, and the synchronous instability high-risk disturbance set is fed back to the power grid planning model. According to the input power grid topology, the short-circuit disturbance set with high synchronous instability risk can be automatically screened out and fed back to the power grid planning model, the change of a topology scheme can be quickly tracked without depending on time domain simulation, dynamic search of high-risk disturbance is realized, and the reliability of the power grid planning model is improved. The problem of self-adaptive setting of synchronous stability disturbance in a power grid topology optimization planning model embedded with system synchronous stability constraints is solved. The method can be widely applied to the field of large power grid planning.

Description

Technical Field

[0001] The present invention relates to the field of large power grid planning, and in particular to a method, device, equipment and medium for dynamically selecting a high-risk disturbance set for power grid synchronization instability. Background Art

[0002] Synchronous instability is a safety and stability constraint that must be considered when formulating large power grid planning schemes. At present, many studies have proposed mathematical models and methods for power grid topology optimization planning that embed synchronous stability constraints, so that the optimized topology scheme can directly meet the synchronous stability constraints, rather than adjusting the scheme after the stability check fails. However, large power grid disturbances can occur at any location and cannot be enumerated. Only a small number of synchronous stability constraints under high-risk faults can be considered in the planning model. Therefore, these planning mathematical methods all rely on manually selecting several transmission channels to set short-circuit faults. This brings about a technical problem: new topological schemes will be continuously generated during the solution of the power grid planning model, and the high-risk disturbance positions of synchronous instability will also change under different topological schemes. The planning model must be able to automatically search for the corresponding high-risk channels according to the topological changes, otherwise it cannot accurately consider the synchronous instability risks and constraints. However, there is currently a lack of technical solutions to solve the corresponding problems. Summary of the invention

[0003] In order to solve at least one of the technical problems existing in the prior art to a certain extent, the purpose of the present invention is to provide a method, device, equipment and medium for dynamically selecting a high-risk disturbance set for power grid synchronous instability based on long-chain transmission channel search.

[0004] The first technical solution adopted by the present invention is:

[0005] A method for dynamically selecting a high-risk disturbance set for power grid synchronization instability forms a closed loop with a solution algorithm for power grid planning. The method comprises the following steps:

[0006] Obtain the power grid topology generated by the power grid planning model;

[0007] The long-chain transmission channel search method is used to search the power grid topology and obtain the long-chain transmission channel set;

[0008] A high-risk disturbance set selection method based on channel electrical distance indicators is adopted to screen the long-chain transmission channel set to dynamically obtain the high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

[0009] Furthermore, the long chain transmission channel is defined as: a collection of unidirectional transmission lines across multiple regions, the power flow directions of the lines in the long chain are the same, the power difference is less than a preset value, and the total length of the chain line exceeds a preset threshold.

[0010] Furthermore, the method of searching the power grid topology by using a long-chain transmission channel search method to obtain a set of long-chain transmission channels includes:

[0011] The power grid topology is expressed as a graph structure G1 = (V, ε), where V is the node set and ε is the transmission line (edge) set;

[0012] For any transmission line in the power grid j ∈ε, the node with positive active power flow inflow is the branch head node; its edge attribute L j For line l j geographical length;

[0013] Set the geographic length threshold α, set the initial value of the iteration round number to k = 1, and start the iterative search;

[0014] The iterative search steps include:

[0015] A1. Set the power flow retention rate threshold β for the kth round k , traverse the graph G k All nodes v in i ∈V; for node v i , record the active power flow into node v i The branch set is A i , the branch set of active power flow out of node i is B i ;right And P m ,P n ≠0 Calculate the power flow retention rate:

[0016]

[0017] Where P m , P n Branch l m , l m The head end flow; if P save,mn ≥β, then for l m =(v m ,v i ), l n =(v i ,v n ), remember the edge combination [l m ,l n ], stored in the set R;

[0018] A2. For Figure G k All the edges l that are not selected into the combination j , query its geographic length L j , if it meets the geographic length threshold α, it will be included in the set F;

[0019] A3. For the tth element R in the set R t =[l m ,l n ], record the sequence R t1 = l m , R t2 = l n ; Traverse the set R and search: And R s1 =R t2 ; If not, go to step A6; if yes, let R t =[R t1 ,R t2 ,R s2 ], delete R s ; Let M1 = {R t1 |R t ∈R}, M2={R t2 |R t ∈R}, N=M1∩M2;

[0020] A4. For the three-side combination R in the set R t =[l m ,l n ,l p ], where l m =(v m ,v i ), l n =(v i ,v n ), l p =(v n ,v p ),search: or If it exists, delete the combination R from the set R t ;

[0021] A5. For all the three-edge combinations retained in set R, record the new edge (v m ,v p ), and at the same time m , l n , l p Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,v p )'s edge attributes; m ,v p ) into the set ε'; store the node v m ,v p Store into the set V', forming a new graph G' = (V', ε');

[0022] A6. Combine the two sides of the set R t =[l m ,l n ], where l m =(v m ,v i ), l n =(v i ,v n ), record the new edge (v m ,v n ), and at the same time m , l n Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,v n )'s edge attributes; m ,v n ) into the set ε'; store the node v m ,v n Store in set V' and add new graph G' = (V', ε');

[0023] A7, use set(I mn ) represents the multiset I mn Transformed into a common set, |I mn | represents a multiset I mn The number of elements in the new graph G'; traverse all branches V' in the new graph G'. It is determined that the channel passes through the same edge and forms a loop, which does not meet the definition of a long-distance channel. This type of branch is deleted from the set V';

[0024] A8. If the new graph G'=(V',ε') is empty, go to step A12; if the new graph G'=(V',ε') is not empty, calculate all connected subgraphs in the new graph G' to form a set S G' ;

[0025] A9. Traverse all connected subgraphs G' in the new graph G' h ∈S G' ;

[0026] ① If the new graph G' h If the number of midpoints is equal to 2, then the connected subgraph has only one edge.

[0027] If the edge attribute I mn The sum of the geographic lengths of all edges in is greater than or equal to the geographic length threshold α, then the set I mn It already includes all the routes of a complete long-chain transmission channel. mn Put it into the set F and put the subgraph G' h Delete from graph G';

[0028] If the edge attribute I mn If the sum of the geographical lengths of all edges in is less than the geographical length threshold α, then the line does not meet the long-chain transmission channel condition and can no longer be extended. h Delete from graph G';

[0029] ② If the new graph G' h If the number of nodes is greater than or equal to 3, then the subgraph G' h Insert Figure G k+1 ;

[0030] After completing all subgraphs G' in G' h After traversing, we form graph G k+1 =(V k+1 ,ε k+1 );

[0031] A10. Determine the generated new graph G k+1 =(V k+1 ,ε k+1 ) is empty, if so, go to step A12; if not, set k=k+1, go to step A2;

[0032] A11. Traverse the set F and check whether and If yes, delete F i ;

[0033] A12. Traverse the set F; record the channel F in F i For sequence F i1 ,F i2 ,...,F in , O i ={F i1 ,F i2 ,...,F in-1}, P i ={F i2 ,F i3 ,...,F in};search: And O i =P j ; If it exists, then the sequence F i Updated to F i '={F j1 ,F i1 ,...,F in}, and delete channel F from set F j ; At this point, the search is completed, and the set F is the set of long-chain transmission channels.

[0034] Furthermore, the power flow retention rate threshold β in step A1k ≥0.5.

[0035] Furthermore, the high-risk disturbance set selection method based on the channel electrical distance index is adopted to screen the long-chain transmission channel set, including:

[0036] For a long chain transmission channel set, the channel F in F i ={F i1 ,F i2 ,...,F in}, if F i1 =(v1,v2),F i2 =(v2,v3), write out the n+1 node set V of the channel path Fi = {v i1 ,v i2 ,v i3 ,...,v i(n+1)}; Calculate the electrical distance index of the long chain transmission channel:

[0037]

[0038] Where, X j(j+1)k represents the reactance of the kth branch between nodes j and j+1; represents the total reactance of all parallel branches between nodes j and j+1;

[0039] Set the electrical distance threshold γ of the long-chain transmission channel and filter the high-risk channel set L according to the following formula:

[0040] L={F i |D i >γ}

[0041] If the high-risk channel set L is an empty set, it is determined that there is no structural risk of synchronous instability in the grid, that is, the corresponding planning topology scheme does not need to consider the synchronous stability constraint; if the high-risk channel set L is not empty, the high-risk channel set L is included in the synchronous instability constraint of the power grid optimization planning model.

[0042] The second technical solution adopted by the present invention is:

[0043] A device for dynamically selecting a high-risk disturbance set for power grid synchronization instability, comprising:

[0044] A topology acquisition module is used to acquire the power grid topology generated by the power grid planning model;

[0045] A channel search module is used to search the power grid topology by using a long-chain transmission channel search method to obtain a long-chain transmission channel set;

[0046] The channel screening module is used to screen the long-chain transmission channel set by adopting the high-risk disturbance set selection method based on the channel electrical distance index, so as to dynamically obtain the high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

[0047] The third technical solution adopted by the present invention is:

[0048] An electronic device comprises a processor and a memory, wherein the memory stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set are loaded and executed by the processor to implement a method for dynamically selecting a disturbance set with high risk of synchronous instability in a power grid as described above.

[0049] The fourth technical solution adopted by the present invention is:

[0050] A computer-readable storage medium stores at least one instruction, at least one program, a code set or an instruction set, wherein the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by a processor to implement a method for dynamically selecting a disturbance set with a high risk of synchronous instability in a power grid as described above.

[0051] The fifth technical solution adopted by the present invention is:

[0052] A computer program product or a computer program includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the above method.

[0053] The beneficial effects of the present invention are as follows: the present invention can automatically screen out a set of short-circuit disturbances with high risk of synchronous instability according to the input power grid topology, and feed it back to the power grid planning model, forming a closed loop with the power grid planning solution algorithm, and can quickly track changes in topology schemes without relying on time domain simulation, thereby realizing dynamic search for high-risk disturbances, and solving the problem of adaptive setting of synchronous stability disturbances in the power grid topology optimization planning model embedded with system synchronous stability constraints. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 It is a flow chart of a method for dynamically selecting a high-risk disturbance set for power grid synchronization instability based on long-chain transmission channel search in an embodiment of the present invention;

[0056] Figure 2 is a flow chart of a long chain transmission channel search algorithm in an embodiment of the present invention;

[0057] Figure 3 is a schematic diagram of a possible situation in which two groups of combinations share one edge in an embodiment of the present invention;

[0058] Figure 4 is an example diagram of a continuous line combination in an embodiment of the present invention;

[0059] Figure 5 is a schematic diagram of channel looping during the search process in an embodiment of the present invention;

[0060] Figure 6 This is a simplified wiring diagram of a regional power grid in an embodiment of the present invention;

[0061] Figure 7 is a graph formed by the first round of search results in an embodiment of the present invention;

[0062] Figure 8 is a new graph formed after the first round of search in the embodiment of the present invention;

[0063] Fig. 9 is a new graph formed after the second round of search in the embodiment of the present invention;

[0064] Fig.10 It is a flowchart of the steps of a method for dynamically selecting a disturbance set with high risk of synchronous instability of a power grid in an embodiment of the present invention. DETAILED DESCRIPTION

[0065] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0066] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0067] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0068] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0069] In response to the existing technical problems, the present invention proposes a method for dynamically selecting a disturbance set with high risk of synchronous instability of power grid based on long-chain transmission channel search. The proposed method for dynamically selecting a disturbance set with high risk of synchronous instability of power grid based on long-chain transmission channel search includes two key links, one is the long-chain transmission channel search algorithm, and the other is the high-risk disturbance set selection method based on the channel electrical distance index. Based on the search algorithm proposed by the present invention, it is possible to quickly track the changes in topology schemes without relying on time domain simulation, realize dynamic search of high-risk disturbances, and solve the problem of adaptive setting of synchronous stability disturbances in the power grid topology optimization planning model embedded with system synchronous stability constraints.

[0070] Example 1

[0071] like Figure 1 and Fig.10 As shown, this embodiment provides a method for dynamically selecting a disturbance set with high risk of power grid synchronization instability, which forms a closed loop with the solution algorithm of power grid planning. The method includes the following steps:

[0072] S1. Obtain the power grid topology generated by the power grid planning model;

[0073] S2. Using a long-chain transmission channel search method to search the power grid topology, and obtaining a long-chain transmission channel set;

[0074] S3. A high-risk disturbance set selection method based on the channel electrical distance index is used to screen the long-chain transmission channel set to dynamically obtain a high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

[0075] The method of this embodiment can automatically screen out a set of short-circuit disturbances with high risk of synchronous instability according to the input power grid topology, and feed it back to the power grid planning model. Therefore, the method of this embodiment can form a closed loop with the solution algorithm of power grid planning, dynamically generate a set of high-risk disturbances of synchronous instability according to the candidate topology schemes generated in the optimization solution process, and verify the stability of the planning scheme. The proposed calculation method includes two key links: one is a long-chain transmission channel search algorithm, and the other is a high-risk disturbance set selection method based on the channel electrical distance index.

[0076] See also Figure 1 The two key links in the process are the long-chain transmission channel search and the high-risk disturbance set selection. The following introduces each key link.

[0077] (1) Long-chain transmission channel search algorithm

[0078] 1.1) Definition of long-chain transmission channels

[0079] This embodiment takes into account the risks of low-frequency oscillation and synchronous instability of the large power grid, and defines a long-chain transmission channel as: a collection of unidirectional transmission lines across multiple regions, with the power flow directions of the lines in the long chain being the same and the power not much different, and the total length of the chain lines exceeding a certain threshold, which should generally be more than 200 km.

[0080] 1.2) Long-chain transmission channel search process

[0081] See also Figure 2 ,The specific contents of the long chain transmission channel search algorithm are as follows:

[0082] Consider a high-voltage transmission network above 220 kV, and express its topology as a graph structure G1 = (V, ε), where V is the node set and ε is the transmission line (edge) set. j ∈ε, the node with positive active power flow inflow is the branch head node; its edge attribute L j For line l j geographical length.

[0083] Set the geographic length threshold α, and set the initial value of the iteration round number to k = 1. Start the following iterative search:

[0084] A1. Set the power flow retention rate threshold β for the kth round k , the threshold β must be satisfied k ≥0.5; traverse graph G k All nodes v in i ∈V, for node v i , record the active power flow into node v i The branch set is A i, the branch set of active power flow out of node i is B i ;right And P m ,P n ≠0 Calculate the power flow retention rate:

[0085]

[0086] Among them, P m , P n Branch l m , l m If P save,mn ≥β, then for l m =(v m ,v i ), l n =(v i ,v n ), remember the edge combination [l m ,l n ] and stored in the set R.

[0087] A2. For Figure G k All the edges l that are not selected into the combination j , query its geographic length L j , if it meets the geographic length threshold α, it will be included in the set F.

[0088] A3. For the tth element R in the set R t =[l m ,l n ], record the sequence R t1 = l m , R t2 = l n . Traverse the set R and search: And R s1 =R t2 If not, go to step A6; if yes, set R t =[R t1 ,R t2 ,R s2 ], delete R s ; Let M1 = {R t1 |R t ∈R}, M2={R t2 |R t ∈R}, N=M1∩M2. To ensure that there will be no Figure 3 In the case of (A), there will be no situation where more than three groups share one edge. In step A1, β k ≥0.5. Among them, Figure 3(B) is a schematic diagram of two groups of combinations connected end to end. Although the two groups share an edge, it is still an acceptable situation.

[0089] A4. For the three-side combination R in the set R t =[l m ,l n ,l p ], where l m =(v m ,v i ), l n =(v i ,v n ), l p =(v n ,v p ),search: or If it exists, delete the combination R from the set R t , avoid Figure 4 Continuity wiring combination shown.

[0090] A5. For all the three-edge combinations retained in set R, record the new edge (v m ,v p ), and at the same time m , l n , l p Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,v p )'s edge attributes. m ,v p ) into the set ε'; store the node v m ,v p Store it in the set V' to form a new graph G' = (V', ε').

[0091] A6. Combine the two sides of the set R t =[l m ,l n ], where l m =(v m ,v i ), l n =(v i ,v n ), record the new edge (v m ,v n ), and at the same time m , l n Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,vn )'s edge attributes. m ,v n ) into the set ε'; store the node v m ,v n Store it in the set V' and add the new graph G'=(V',ε').

[0092] A7, use set(I mn ) represents the multiset I mn Transformed into a common set, |I mn | represents a multiset I mn The number of elements in . Traverse all branches V' in the graph G'. If This indicates that the channel passes through the same edge and a loop occurs (e.g. Figure 5 As shown in Figure 1, it does not meet the definition of a long-distance channel and will cause the channel to continue to extend on the ring until the program overflows. Therefore, this type of branch is deleted from the set V'.

[0093] A8. If the new graph G'=(V',ε') is empty, go to step A12. If the new graph G'=(V',ε') is not empty, calculate all connected subgraphs in the new graph G' to form a set S G' .

[0094] A9. Traverse all connected subgraphs G' in G' h ∈S G' ;

[0095] ① If Figure G' h If the number of midpoints is equal to 2, then the connected subgraph has only one edge.

[0096] If the edge attribute I mn The sum of the geographic lengths of all edges in is greater than or equal to the geographic length threshold α, then the set I mn It already includes all the routes of a complete long-chain transmission channel. mn Put it into the set F and put the subgraph G' h Delete from graph G'.

[0097] If the edge attribute I mn If the sum of the geographical lengths of all edges in is less than the geographical length threshold α, then the line does not meet the long-chain transmission channel condition and can no longer be extended. h Delete from graph G'.

[0098] ② If G' h If the number of nodes is greater than or equal to 3, then the subgraph G' h Insert Figure G k+1 .

[0099] After completing all subgraphs G' in G'h After traversing, we form graph G k+1 =(V k+1 ,ε k+1 ).

[0100] A10. Determine the generated new graph G k+1 =(V k+1 ,ε k+1 ) is empty, if so, go to step A12; if not, set k=k+1 and go to step A2.

[0101] A11. Traverse the set F and check whether and If yes, delete F i .

[0102] A12. Traverse the set F. Note the channel F in F i For sequence F i1 ,F i2 ,...,F in , O i ={F i1 ,F i2 ,...,F in-1}, P i ={F i2 ,F i3 ,...,F in}.search: And O i =P j If it exists, then the sequence F i Updated to F i '={F j1 ,F i1 ,...,F in}, and delete channel F from set F j At this point, the search is complete, and the set F is the set of long-chain transmission channels.

[0103] (2) Selection of high-risk disturbance sets based on channel electrical distance indicators

[0104] For all the long-chain transmission channel sets obtained by searching, the following channel electrical distance indicators are calculated respectively:

[0105] 1) For channel F in set F i ={F i1 ,F i2 ,...,F in}, if F i1 =(v1,v2),F i2 =(v2,v3), write out the n+1 node set V of the channel path Fi = {v i1,v i2 ,v i3 ,...,v i(n+1)}. Calculate the electrical distance index of the long chain transmission channel:

[0106]

[0107] Among them, X j(j+1)k represents the reactance of the kth branch between nodes j and j+1; Represents the total reactance of all parallel branches between nodes j and j+1.

[0108] 2) Set the electrical distance threshold γ of the long-chain transmission channel, and the typical value can be γ = 0.02. The high-risk channel set L is formed by screening according to the following formula:

[0109] L={F i |D i >γ}

[0110] If the high-risk channel set L is an empty set, it is considered that there is no structural risk of synchronous instability in the grid, that is, the corresponding planning topology does not need to consider the synchronous stability constraint. If the high-risk channel set L is not empty, the faults that need to be included in the synchronous instability constraint of the power grid optimization planning model are: three-phase short circuit faults at the head and end of all transmission lines in the set L.

[0111] (3) Example

[0112] by Figure 6 The algorithm is explained by taking a regional power grid planning scheme as an example. Figure 6 In this embodiment, the power grid has 34 nodes and 70 lines. The node numbers are shown in Table 1.

[0113] Table 1 Example node information

[0114]

[0115] The line (side) length, reactance per unit value and typical mode active power flow are shown in Table 2.

[0116] Table 2 Example transmission line information

[0117]

[0118]

[0119]

[0120]

[0121] 3.1) Long chain transmission channel search

[0122] 1) Set the geographic length threshold α = 200m and the tidal retention rate threshold β for each round k =0.7.

[0123] 2) Calculate the power flow retention rate for all branch pairs in the entire network, and obtain the branch pair information that meets the power flow retention rate threshold in the first round of search as shown in Table 3.

[0124] Table 3 Branch combination information that meets the power flow retention rate threshold in the first round of search

[0125]

[0126] 3) For the remaining edges that have not been selected for combination, check whether they meet the geographical length threshold. If they meet the threshold, they are included in the set F; if they do not meet the threshold, they are directly deleted. Table 4 lists the lengths of the lines that did not form branch pairs in this round. All of them are lower than the geographical length threshold of 200km, so all the lines in Table 4 are deleted.

[0127] Table 4 Information of routes not selected in the first round

[0128]

[0129] 4) Perform three-side condensation on the branch pairs in Table 3, and combine the branch pairs that can be connected at the head and tail. Traverse the set R and search: And R s1 =R t2 As shown in Table 3, the branch pair [20,22] and the branch pair [22,13] can be further condensed into the combination [20,22,13]. After searching and completing the three-side condensation, the branch pair information is shown in Table 5. It should be noted that the branch connecting node 20 and node 21 is represented by the node number (20,21), and [51,2,60] is the number of all branches contained in the long chain channel.

[0130] Table 5 Information of the first round search results

[0131]

[0132]

[0133] 5) Store all the first and last nodes in Table 5 into the set V', store the edge information into the set ε', and use the branch number information and the current total geographical length of the edge as the attributes of the edge to form a new graph G' = (V', ε'). Figure 7 , Figure 7 There are 5 connected subgraphs in , and the specific information is shown in Table 6.

[0134] Table 6 Connected subgraph information of the first round search results

[0135]

[0136] The number of nodes in subgraphs ② and ③ is equal to 2, indicating that these two channels can no longer be extended, so it is determined whether the total length reaches the geographical length threshold. As shown in Table 5, the lengths of channels 'BJT=-SX' and 'LYJ-HD' are 92.10km and 166.10km respectively, which do not reach the long chain channel length threshold of 200km, so they are deleted from the graph.

[0137] See also Figure 8 , the number of nodes in subgraphs ①, ④, and ⑤ are all greater than or equal to 3, so the new graph G2 is formed by graphs ①, ④, and ⑤:

[0138] 6) It is determined that the new graph G2 is not empty, so the second round of search is continued. The power flow retention rate is calculated for all branch combinations in graph G2, and the results that meet the conditions are shown in Table 7.

[0139] Table 7 Branch combination information that meets the power flow retention rate threshold in the second round of search

[0140]

[0141] 7) For the remaining edges that have not been selected into the combination, check whether they meet the geographical length threshold. If they meet the threshold, they are included in the set F; if they do not meet the threshold, they are directly deleted. As can be seen from Table 8, the lengths of the combinations [36,39,28] and [18,66,6] are above the geographical length threshold of 200km, so they are included in the set F, and the remaining branch combinations are directly deleted.

[0142] Table 8 Information on routes not selected in the second round

[0143]

[0144] 8) Next, the branch combinations that meet the flow retention rate threshold in the second round are three-sided condensed. After searching, there is no branch combination that meets the three-sided condensation condition in this round. All the head and end nodes in Table 7 are directly stored in the set V', the edge information is stored in the set ε', and the branch number information passed by the edge and the current total geographical length of the edge are used as the attributes of the edge, forming the graph G'=(V',ε') in the second round of search. Fig. 9 , Fig. 9 There is 1 connected subgraph in , and the number of nodes in the subgraph is greater than or equal to 3, so this subgraph is used to form a new graph G3.

[0145] 9) It is determined that the new graph G3 is not empty, so the third round of search continues. The flow retention rate is calculated for all branch combinations in graph G3, and there is no branch combination that meets the conditions. All branch combinations that do not meet the conditions in this round are shown in Table 9, and they are checked to see if they meet the geographic length threshold. It can be seen from Table 9 that the branch combinations [48,33,2,60,20,24], [48,34,3,60,20,24], [39,26,2,60,22,42], and [39,26,2,60,20,24] meet the threshold, so they are included in the set F, and the remaining branch combinations are directly deleted. At this point, the new graph G4 formed is empty, and the search ends.

[0146] Table 9 Information on routes not selected in the third round

[0147]

[0148] 10) The information of the long chain channel set F obtained by searching is shown in Table 10.

[0149] Table 10 Long chain channel search result information

[0150]

[0151] Traverse the set F, and there is no F i ,F j ∈F, and That is, there is no repeated search for long chain channel fragments; nor is there a connectable fragment. At this point, the search result review is complete, and the search result F is the complete long chain channel information.

[0152] 3.2) Calculation of electrical distance index for long-chain transmission channels

[0153] The electrical distance threshold γ is set to 0.02. The total reactance of the parallel branch is used as the electrical distance between nodes, and the electrical distance of the long chain channel is calculated as shown in Table 11. The high-risk channels 'QK-QJ-HD-DP' and 'QJ-HD-BJ-ZC-SD-HL-ZJ' that meet the electrical distance threshold are screened out.

[0154] Table 11 Calculation results of electrical distance of long chain channel

[0155]

[0156] Finally, the high-risk fault set of synchronous instability that should be considered in this scheme is obtained, which includes 10 three-phase short-circuit faults. Table 12 gives the fault locations, where "line-node" means that the fault occurs near the specified node on the specified line.

[0157] Table 12 Synchronous instability high risk fault set

[0158]

[0159] (4) Advantages and beneficial effects

[0160] In summary, compared with the prior art, the present invention has the following significant advantages: 1) For long-chain transmission channels that are prone to cause systemic synchronous instability risks, a specific definition and search method are given, which realizes the rapid location of disturbances with high synchronous instability risks in the planned grid scheme. 2) It can realize dynamic search for high-risk disturbances without relying on time domain simulation, and solves the problem of adaptive setting of synchronous stability disturbances in the power grid topology optimization planning model embedded with system synchronous stability constraints.

[0161] Example 2

[0162] This embodiment provides a device for dynamically selecting a disturbance set with high risk of synchronous instability of a power grid, comprising:

[0163] A topology acquisition module is used to acquire the power grid topology generated by the power grid planning model;

[0164] A channel search module is used to search the power grid topology by using a long-chain transmission channel search method to obtain a long-chain transmission channel set;

[0165] The channel screening module is used to screen the long-chain transmission channel set by adopting the high-risk disturbance set selection method based on the channel electrical distance index, so as to dynamically obtain the high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

[0166] Since the device is a dynamic selection device for a high-risk disturbance set of power grid synchronous instability in an embodiment of the present invention, and the principle of solving the problem by the device is similar to that of the method, the implementation of the device can refer to the implementation process of the above-mentioned method embodiment, and the repeated parts will not be repeated.

[0167] Example 3

[0168] An embodiment of the present invention further provides an electronic device, the electronic device comprising a processor and a memory, the memory storing at least one instruction, at least one program, a code set or an instruction set, the at least one instruction, the at least one program, the code set or the instruction set being loaded and executed by the processor to implement the following Fig.10 A dynamic selection method for a high-risk disturbance set for power grid synchronous instability is shown.

[0169] It is understood that the memory may include a random access memory (RAM) or a read-only memory (ROM). Optionally, the memory includes a non-transitory computer-readable storage medium. The memory may be used to store instructions, programs, codes, code sets, or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function, instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data created according to the use of the server, etc.

[0170] The processor may include one or more processing cores. The processor uses various interfaces and lines to connect the various parts of the entire server, and executes various functions of the server and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory, and calling data stored in the memory. Optionally, the processor can be implemented in at least one hardware form of digital signal processing (DSP), field programmable gate array (FPGA), and programmable logic array (PLA). The processor can integrate one or a combination of a central processing unit (CPU) and a modem. Among them, the CPU mainly processes the operating system and application programs; the modem is used to process wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor, but implemented separately through a chip.

[0171] Since the electronic device is an electronic device corresponding to a method for dynamically selecting a disturbance set with high risk of synchronous instability in a power grid in an embodiment of the present invention, and the principle of solving the problem by the electronic device is similar to that of the method, the implementation of the electronic device can refer to the implementation process of the above-mentioned method embodiment, and the repeated parts will not be repeated.

[0172] Example 4

[0173] The embodiment of the present invention further provides a computer-readable storage medium, wherein the storage medium stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, the at least one program, the code set or instruction set is loaded and executed by a processor to implement the following Fig.10 A dynamic selection method for a high-risk disturbance set for power grid synchronous instability is shown.

[0174] Those skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, and the storage medium includes a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electronically erasable rewritable read-only memory (EEPROM), a compact disc (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0175] Since the storage medium is the storage medium corresponding to a method for dynamically selecting a disturbance set with high risk of synchronous instability in a power grid in an embodiment of the present invention, and the principle of solving the problem by the storage medium is similar to that of the method, the implementation of the storage medium can refer to the implementation process of the above-mentioned method embodiment, and the repeated parts will not be repeated.

[0176] Example 5

[0177] In some possible implementations, various aspects of the method of the embodiment of the present invention may also be implemented in the form of a program product, which includes a program code. When the program product is run on a computer device, the program code is used to enable the computer device to execute the steps of a method for dynamically selecting a high-risk disturbance set for power grid synchronization instability according to various exemplary embodiments of the present application described above in this specification. Among them, the executable computer program code or "code" for executing various embodiments may be written in a high-level programming language such as C, C++, C#, Smalltalk, Java, JavaScript, Visual Basic, structured query language (e.g., Transact-SQL), Perl, or in various other programming languages.

[0178] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0179] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0180] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for dynamically selecting a high-risk disturbance set for power grid synchronization instability, characterized in that: The method forms a closed loop with the solution algorithm of the power grid planning, and includes the following steps: Obtain the power grid topology generated by the power grid planning model; The long-chain transmission channel search method is used to search the power grid topology and obtain the long-chain transmission channel set; A high-risk disturbance set selection method based on channel electrical distance indicators is adopted to screen the long-chain transmission channel set to dynamically obtain the high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

2. A method for dynamically selecting a high-risk disturbance set for power grid synchronization instability according to claim 1, characterized in that: The long chain transmission channel is defined as: a collection of one-way transmission lines spanning multiple regions, the power flow directions of the lines in the long chain are the same, the power difference is less than a preset value, and the total length of the chain lines exceeds a preset threshold.

3. The method for dynamically selecting a high-risk disturbance set for power grid synchronization instability according to claim 1 is characterized in that: The method of searching the power grid topology by using the long-chain transmission channel search method to obtain a set of long-chain transmission channels includes: The power grid topology is expressed as a graph structure G1 = (V, ε), where V is the node set and ε is the transmission line set; For any transmission line in the power grid j ∈ε, the node with positive active power flow inflow is the branch head node; its edge attribute L j For line l j geographical length; Set the geographic length threshold α, set the initial value of the iteration round number to k = 1, and start the iterative search; The iterative search steps include: A1. Set the power flow retention rate threshold β for the kth round k , traverse the graph G k All nodes v in i ∈V; for node v i , record the active power flow into node v i The branch set is A i , the branch set of active power flow out of node i is B i ;right And P m ,P n ≠0 Calculate the power flow retention rate: Where P m , P n Branch l m , l m The head end flow; if P save,mn ≥β, then for l m =(v m ,v i ), l n =(v i ,v n ), remember the edge combination [l m ,l n ], stored in the set R; A2. For Figure G k All the edges l that are not selected into the combination j , query its geographic length L j , if it meets the geographic length threshold α, it will be included in the set F; A3. For the tth element R in the set R t =[l m ,l n ], record the sequence R t1 = l m , R t2 = l n ; Traverse the set R and search: And R s1 =R t2 ; If not, go to step A6; if yes, let R t =[R t1 ,R t2 ,R s2 ], delete R s ; Let M1 = {R t1 |R t ∈R}, M2={R t2 |R t ∈R}, N=M1∩M2; A4. For the three-side combination R in the set R t =[l m ,l n ,l p ], where l m =(v m ,v i ), l n =(v i ,v n ), l p =(v n ,v p ),search: or If it exists, delete the combination R from the set R t ; A5. For all the three-edge combinations retained in set R, record the new edge (v m ,v p ), and at the same time m , l n , l p Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,v p )'s edge attributes; m ,v p ) into the set ε'; store the node v m ,v p Store into the set V', forming a new graph G' = (V', ε'); A6. Combine the two sides of the set R t =[l m ,l n ], where l m =(v m ,v i ), l n =(v i ,v n ), record the new edge (v m ,v n ), and at the same time m , l n Join Multiset I mn , used to record all the edges of the path, I mn As the new edge (v m ,v n )'s edge attributes; m ,v n ) into the set ε'; store the node v m ,v n Store in set V' and add new graph G' = (V', ε'); A7, use set(I mn ) represents the multiset I mn Transformed into a common set, |I mn | represents a multiset I mn The number of elements in the new graph G'; traverse all branches V' in the new graph G'. It is determined that the channel passes through the same edge and forms a loop, which does not meet the definition of a long-distance channel. This type of branch is deleted from the set V'; A8. If the new graph G'=(V',ε') is empty, go to step A12; if the new graph G'=(V',ε') is not empty, calculate all connected subgraphs in the new graph G' to form a set S G' ; A9. Traverse all connected subgraphs G' in the new graph G' h ∈S G' ; ① If the new graph G' h If the number of midpoints is equal to 2, then the connected subgraph has only one edge. If the edge attribute I mn The sum of the geographic lengths of all edges in is greater than or equal to the geographic length threshold α, then the set I mn It already includes all the routes of a complete long-chain transmission channel. mn Put it into the set F and put the subgraph G' h Delete from graph G'; If the edge attribute I mn If the sum of the geographical lengths of all edges in is less than the geographical length threshold α, then the line does not meet the long-chain transmission channel condition and can no longer be extended. h Delete from graph G'; ② If the new graph G' h If the number of nodes is greater than or equal to 3, then the subgraph G' h Insert Figure G k+1 ; After completing all subgraphs G' in G' h After traversing, we form graph G k+1 =(V k+1 ,ε k+1 ); A10. Determine the generated new graph G k+1 =(V k+1 ,ε k+1 ) is empty, if so, go to step A12; if not, set k=k+1, go to step A2; A11. Traverse the set F and check whether and If yes, delete F i ; A12. Traverse the set F; record the channel F in F i For sequence F i1 ,F i2 ,...,F in , O i ={F i1 ,F i2 ,...,F in-1 }, P i ={F i2 ,F i3 ,...,F in };search: And O i =P j ; If it exists, then the sequence F i Updated to F i '={F j1 ,F i1 ,...,F in }, and delete channel F from set F j ; At this point, the search is completed, and the set F is the set of long-chain transmission channels.

4. A method for dynamically selecting a high-risk disturbance set for power grid synchronization instability according to claim 3, characterized in that: The power flow retention rate threshold β in step A1 k ≥0.

5.

5. The method for dynamically selecting a high-risk disturbance set for power grid synchronization instability according to claim 1, characterized in that: The high-risk disturbance set selection method based on the channel electrical distance index is used to screen the long-chain transmission channel set, including: For a long chain transmission channel set, the channel F in F i ={F i1 ,F i2 ,...,F in }, if F i1 =(v1,v2),F i2 =(v2,v3), write out the n+1 node set V of the channel path Fi = {v i1 ,v i2 ,v i3 ,...,v i(n+1) }; Calculate the electrical distance index of the long chain transmission channel: Where, X j(j+1)k represents the reactance of the kth branch between nodes j and j+1; represents the total reactance of all parallel branches between nodes j and j+1; Set the electrical distance threshold γ of the long-chain transmission channel and filter the high-risk channel set L according to the following formula: L={F i |D i >c} If the high-risk channel set L is an empty set, it is determined that there is no structural risk of synchronous instability in the grid, that is, the corresponding planning topology scheme does not need to consider the synchronous stability constraint; if the high-risk channel set L is not empty, the high-risk channel set L is included in the synchronous instability constraint of the power grid optimization planning model.

6. A dynamic selection device for a high-risk disturbance set for power grid synchronization instability, characterized in that: include: A topology acquisition module is used to acquire the power grid topology generated by the power grid planning model; A channel search module is used to search the power grid topology by using a long-chain transmission channel search method to obtain a long-chain transmission channel set; The channel screening module is used to screen the long-chain transmission channel set by adopting the high-risk disturbance set selection method based on the channel electrical distance index, so as to dynamically obtain the high-risk disturbance set of synchronous instability and feed it back to the power grid planning model.

7. An electronic device, characterized in that: The electronic device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to implement the method described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to implement the method according to any one of claims 1 to 5.

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