Object search method, system and device for power grid stability control strategy and medium

Abstract

The application discloses a kind of object search methods, systems, devices and medium for power grid stability control strategy.The method comprises: obtaining power grid topology and the capacity of each node;According to the type of stability control equipment, determine the input power grid node;Based on the input power grid node and the power grid topology, by breadth-first near neighbor expansion strategy, the risk assessment object set is obtained;The risk assessment object set is the node, line included in the stability control coverage range, represents the concern range of stability risk analysis;Based on the risk assessment object set and the capacity of each node, by multi-head parallel recursive search strategy, the key section object set is obtained;According to the key section object set, the station is sorted, and the stability control object set is determined;The stability control object set is used to represent the stability control concern range.The application embodiment is conducive to improving the efficiency and application universality of stability control strategy formulation.The method can be widely applied in power grid management and control technical field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid management and control, and particularly relates to a method, system and device for searching objects for power grid stability control strategy and a medium. BACKGROUND

[0002] With the continuous expansion of the power grid scale in China, the continuous development of extra-high voltage and long-distance direct current transmission scale, the disturbance type and disturbance intensity threatening the operation safety of the power grid are increasing, the system safety and stability risk is more complex, and the dependence of the safe and stable operation of the new power system on the safety and stability control system is higher and higher.

[0003] In the related art, the control strategy of the safety and stability control system (referred to as stability control strategy) is mainly formulated in the mode of "off-line calculation and on-line matching". The stability control strategy needs to be manually preset with a set of operation modes and a set of expected faults. Through a large number of fault simulations and stability risk analysis, the stability control action strategy is summarized and formed, and the coverage and selectivity of the strategy are checked by using exhaustive stability simulation scanning. The manual formulation and checking calculation of the stability control strategy are large in amount and long in time, and are often iterated in years. This way has been more and more difficult to meet the safety and stability control needs of the new power system with more complex and variable operation modes, dynamic characteristics and evolving instability modes. SUMMARY

[0004] The present application aims to at least partly solve one of the problems in the prior art.

[0005] To this end, the present application aims to provide an efficient method, system, device and medium for searching objects for power grid stability control strategy.

[0006] In order to achieve the above technical purposes, one aspect of an embodiment of the present application provides a method for searching objects for a power grid stability control strategy, comprising the following steps: obtaining a power grid topology and capacities of nodes; determining an input power grid node according to a stability control device type; obtaining a risk assessment object set by a breadth-first near neighbor expansion strategy based on the input power grid node and the power grid topology; the risk assessment object set is a node and a line included in a stability control coverage range, and represents a range of concern for stability risk analysis; obtaining a key section object set by a multi-head parallel recursive search strategy based on the risk assessment object set and the capacities of the nodes; the key section object set is used to represent a range of concern for maintenance and fault setting; sorting stations according to the key section object set to determine a stability control object set; the stability control object set is used to represent a stability control range of concern. The risk assessment object set, the key section object set and the stability control object set are used to respectively define a stability risk analysis range of concern, a maintenance and fault setting range of concern and a stability control range of concern, and then a stability control strategy is formulated, which is beneficial to improving the efficiency of formulating the stability control strategy and the application universality.

[0007] In some embodiments, the method for searching objects for a power grid stability control strategy comprises the following steps:

[0008] determining a first-order node as a node adjacent to the input power grid node;

[0009] if a search layer number does not reach a preset layer number, determining a next-order node as a node adjacent to a current-order node until the search layer number reaches the preset layer number, and screening out repeated nodes and lines to obtain a risk assessment object set.

[0010] In some embodiments, in one embodiment of the present application, the key section object set is obtained by a multi-head parallel recursive search strategy based on the risk assessment object set and the capacities of the nodes, comprising:

[0011] determining a starting point set, an aggregated node set and a power supply set according to the risk assessment object set; the aggregated node set and the power supply set correspond to each other;

[0012] searching for new nodes and key sections, recursively aggregating the node set and the power supply set, and determining whether to add the key section to the key section object set according to a key section discrimination index.

[0013] In some embodiments, in one embodiment of the present application, the searching for new nodes and key sections, recursively aggregating the node set and the power supply set, and determining whether to add the key section to the key section object set according to a key section discrimination index, comprises:

[0014] Parallel search for the second node at the opposite end of the line connected to the node in the current set, add the second node that does not belong to any previous set to the next set, and determine the set of lines;

[0015] Add the lines in the line set whose first node belongs to the previous aggregation node set and whose last node does not belong to the previous aggregation node set to the candidate section subset;

[0016] Based on the capacity of the relevant nodes in the candidate section subset and the line, and based on the key section discrimination index, determine whether to add the candidate section subset to the key section object set;

[0017] Traverse the set of lines and aggregate a new set of aggregate nodes and a set of power sources.

[0018] In some embodiments, in one embodiment of the present invention, determining whether to add the candidate section subset to the key section object set based on the capacity of the relevant nodes in the candidate section subset and the line, and based on the key section discrimination index, includes:

[0019] Based on the installed capacity of relevant nodes in the candidate section subset, the transmission capacity of the candidate section subset, and the transmission channel of the candidate section subset, the key section discrimination index is determined;

[0020] If the key section discrimination index meets the preset conditions, the candidate section subset is added to the key section object set.

[0021] In some embodiments, in one embodiment of the present invention, traversing the line set and aggregating a new set of aggregation nodes and a power supply set includes:

[0022] If there is a preset number of aggregate node set elements, the aggregate node set elements are merged through the line connections in the line set;

[0023] If the third node is connected to an element of the merged aggregate node set and the third node belongs to the next set, the third node is added to the new aggregate node set, and a corresponding new power supply set is generated.

[0024] In some embodiments, in one embodiment of the present invention, the step of sorting the stations according to the set of key cross-section objects to determine the set of stability control objects includes:

[0025] If the candidate section subset is added to the key section object set, the control degree of the nodes related to the candidate section subset is updated;

[0026] Sort all nodes of the power grid in descending or ascending order according to the control degree, screen a number of nodes, and obtain a stable control object set.

[0027] In another aspect, an embodiment of the present application provides an object searching system for a power grid stability control strategy, comprising:

[0028] A first module is configured to acquire a power grid topology and capacities of nodes.

[0029] A second module is configured to determine input power grid nodes according to a stability control device type.

[0030] A third module is configured to obtain a risk assessment object set by a breadth-first neighbor expansion strategy based on the input power grid nodes and the power grid topology; the risk assessment object set is a node or line included in a stability control coverage range and represents a stability risk analysis range.

[0031] A fourth module is configured to obtain a key section object set by a multi-head parallel recursive search strategy based on the risk assessment object set and the capacities of the nodes; the key section object set is used to represent a maintenance and fault setting range.

[0032] A fifth module is configured to sort stations according to the key section object set and determine a stable control object set; the stable control object set is used to represent a stability control range.

[0033] In another aspect, an embodiment of the present application provides an object searching device for a power grid stability control strategy, comprising:

[0034] At least one processor;

[0035] At least one memory configured to store at least one program;

[0036] When the at least one program is executed by the at least one processor, the at least one processor is caused to implement the above-mentioned object searching method for a power grid stability control strategy.

[0037] In another aspect, an embodiment of the present application provides a storage medium having a processor-executable program stored therein, and the processor-executable program is used to implement the above-mentioned object searching method for a power grid stability control strategy when executed by a processor.

[0038] The embodiments of the present application at least have the following beneficial effects: the method provided by the embodiments of the present application comprises: acquiring a power grid topology and capacities of nodes; determining an input power grid node according to a type of a stability control device; obtaining a risk assessment object set based on the input power grid node and the power grid topology through a breadth-first neighbor expansion strategy; the risk assessment object set is a node and a line included in a stability control coverage range, and represents a range of concern for stability risk analysis; obtaining a key section object set based on the risk assessment object set and the capacities of the nodes through a multi-head parallel recursive search strategy; the key section object set is used to represent a range of concern for maintenance and fault setting; sorting stations according to the key section object set to determine a stability control object set; the stability control object set is used to represent a range of concern for stability control. The embodiments of the present application define the range of concern for stability risk analysis, the range of concern for maintenance and fault setting and the range of concern for stability control through the risk assessment object set, the key section object set and the stability control object set respectively, and then formulates a stability control strategy, which is beneficial to improving the efficiency of formulating the stability control strategy and the application universality. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following introduces the drawings of the related technical solutions in the embodiments of the present application or the prior art. It should be understood that the drawings in the following introduction are only for the convenience of clearly describing some embodiments of the technical solutions of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0040] Figure 1 A flowchart of an embodiment of the object search method for the power grid stability control strategy provided by the present application;

[0041] Figure 2 A flowchart of another embodiment of the object search method for the power grid stability control strategy provided by the present application;

[0042] Figure 3 A power grid wiring schematic diagram in an embodiment provided by the present application;

[0043] Figure 4 For Figure 3 A generation flowchart of the risk assessment object set is shown in the example;

[0044] Figure 5 For Figure 3 A generation flowchart of the key section object set is shown in the example;

[0045] Figure 6 A structure diagram of an embodiment of the object search system for the power grid stability control strategy provided by the present application;

[0046] Figure 7 A structural schematic diagram of one embodiment of the object searching device for the grid stability control strategy provided by the present application. DETAILED DESCRIPTION

[0047] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. For the step numbers in the following embodiments, they are only set 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 embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0048] With the continuous expansion of the power grid scale in China, the continuous development of the ultra-high voltage and long distance direct current transmission scale, the disturbance type and disturbance intensity threatening the safe operation of the power grid are increasing, the system security and stability risk is more complex, and the dependence of the safe and stable operation of the new type of power system on the security and stability control system is higher and higher.

[0049] At present, the control strategy of the security and stability control system (referred to as stability control strategy) is mainly adopted in the mode of "off-line calculation and on-line matching". The stability control strategy needs to be manually preset with a set of operation modes and a set of expected faults. Through a large number of fault simulation and stability risk analysis, the stability control action strategy is summarized and formed, and the coverage and selectivity of the strategy are checked by using the exhaustive stability simulation scanning. The manual preparation and checking calculation of the stability control strategy is large in amount and time-consuming, and is often iterated in years. This way has been more and more difficult to meet the security and stability control needs of the new type of power system with more complex and variable operation modes, dynamic characteristics and evolving instability modes. It is urgently needed to study the automatic formulation technology and method of the grid stability control strategy.

[0050] The present application is aimed at the automatic formulation demand of the power system stability control system, firstly proposes the definition of the key object set concerned by the stability control strategy, and then proposes the automatic search method of the risk evaluation object set, the key section object set and the stability control object set in the key object set. The technical points of the method include: (1) the division method of the key object set for the stability control strategy research is proposed, the stability risk analysis attention range, the maintenance and fault setting attention range and the stability control attention range are respectively defined by the risk evaluation object set, the key section object set and the stability control object set, which can greatly reduce the number of simulation cases in the stability control strategy formulation process; (2) based on the grid topology, a key object set automatic search algorithm based on breadth-first neighbor expansion and multi-head parallel recursive search is proposed.

[0051] The object search method and system for power grid stability control strategy proposed according to the present invention will be described in detail below with reference to the accompanying drawings. First, the object search method for power grid stability control strategy proposed according to the present invention will be described with reference to the accompanying drawings.

[0052] Reference Figure 1 This invention provides an object search method for power grid stability control strategies. This method can be applied to a terminal, a server, or software running on either a terminal or server. The terminal can be a tablet, laptop, desktop computer, etc., but is not limited to these. The server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The object search method for power grid stability control strategies in this invention mainly includes the following steps:

[0053] S100: Obtain the power grid topology and the capacity of each node;

[0054] S200: Determine the input grid node based on the type of stability control equipment;

[0055] S300: Based on the input power grid nodes and the power grid topology, a risk assessment object set is obtained through a breadth-first nearest neighbor expansion strategy; the risk assessment object set consists of nodes and lines included in the stability control coverage, representing the scope of concern for stability risk analysis;

[0056] S400: Based on the risk assessment object set and the capacity of each node, a key section object set is obtained through a multi-head parallel recursive search strategy; the key section object set is used to characterize the scope of concern for maintenance and fault setting.

[0057] S500: Sort the stations according to the set of key cross-section objects to determine the set of stability control objects; the set of stability control objects is used to characterize the scope of concern for stability control.

[0058] In some possible implementations, nodes include power stations, specifically power plants, inverter stations, converter stations, etc.

[0059] Optionally, in one embodiment of the present invention, the step of obtaining the risk assessment object set based on the input grid node and the grid topology through a breadth-first nearest neighbor expansion strategy includes:

[0060] The nodes adjacent to the input power grid node are defined as first-order nodes;

[0061] If the search layer does not reach the preset layer number, a node adjacent to the current level node is determined as a next level node until the search layer reaches the preset layer number, and repeated nodes and lines are screened out to obtain a risk assessment object set.

[0062] Optionally, in an embodiment of the present application, the key section object set is obtained based on the risk assessment object set and the capacity of each node through a multi-head parallel recursive search strategy, and includes:

[0063] A starting point set, an aggregated node set and a power supply set are determined according to the risk assessment object set, and the aggregated node set and the power supply set correspond to each other;

[0064] New nodes and key sections are searched, the aggregated node set and the power supply set are recursively aggregated, and it is determined whether to add the key section to the key section object set according to a key section discrimination index.

[0065] Optionally, in an embodiment of the present application, the new nodes and the key sections are searched, the aggregated node set and the power supply set are recursively aggregated, and it is determined whether to add the key section to the key section object set according to a key section discrimination index, and includes:

[0066] A second node connected to a node in the current set is searched in parallel, the second node not belonging to any previous set is added to a next set, and a line set is determined;

[0067] Lines in the line set, in which a first end node belongs to a previous aggregated node set and a last end node does not belong to the previous aggregated node set, are added to a candidate section subset;

[0068] It is determined whether to add the candidate section subset to the key section object set according to a key section discrimination index based on the capacity of the related nodes in the candidate section subset and the lines;

[0069] The line set is traversed, and a new aggregated node set and a new power supply set are aggregated.

[0070] Optionally, in an embodiment of the present application, it is determined whether to add the candidate section subset to the key section object set according to a key section discrimination index based on the capacity of the related nodes in the candidate section subset and the lines, and includes:

[0071] A key section discrimination index is determined according to the installed capacity of the related nodes in the candidate section subset, the power transmission capacity of the candidate section subset and the power transmission channel of the candidate section subset;

[0072] If the key section discrimination index meets a preset condition, the candidate section subset is added to the key section object set.

[0073] Optionally, in an embodiment of the present application, the traversing the set of lines, aggregating a new set of aggregated nodes and a set of power sources, comprises:

[0074] If there is a preset number of aggregated node set elements, merging the aggregated node set elements through the line connection in the set of lines;

[0075] If the third node is connected to the merged aggregated node set element and the third node belongs to the next set, the third node is added to the new set of aggregated nodes, and a corresponding new set of power sources is generated.

[0076] Optionally, in an embodiment of the present application, the sorting the station according to the set of key section objects, determining a set of stable control objects, comprises:

[0077] If the candidate section subset is added to the set of key section objects, the control degree of the node related to the candidate section subset is updated;

[0078] All nodes of the power grid are sorted in descending or ascending order according to the control degree, and a number of nodes are screened to obtain a set of stable control objects.

[0079] The search method provided by the present application will be described in detail below with a specific embodiment:

[0080] Regarding the definition of the set of key objects in the stability control strategy in the present application. Each set of stability control system is customized and configured for local security and stability risk in large power grid, and has strong pertinence. In the research and development process of stability control strategy, both the expansion of the problem solved by the stability control strategy and the omission of the security risk covered should be avoided. To realize the automation of the development of stability control strategy, the scope of attention of security and stability simulation evaluation should be reasonably defined, including the nodes included in the stability control coverage, the branch operation risk, the line maintenance and unit power generation mode that should be considered, and the control objects that can be included in the control category. The present application defines the concept of key object set, and according to the requirements of the above three different attention ranges, defines three sets of sets, including the risk evaluation object set, the key section object set and the stable control object set, which together constitute the key object set. And an automatic search algorithm for the three sets of sets is proposed.

[0081] In another aspect, the application provides an automatic search algorithm for a key object set of a stability control strategy. With power grid topology and power plant capacity as inputs, an automatic search algorithm for a key object set is proposed, which is a breadth-first neighbor expansion and multi-head parallel recursive search algorithm. The algorithm can automatically search and extract a risk assessment object set, a key section object set, and a stability control object set in the key object set, thereby effectively defining the scope of attention for stability risk analysis, maintenance and fault setting, and stability control, and greatly reducing the number of simulation cases for stability control strategy development.

[0082] For the concept and division of the key object set for stability control strategy research:

[0083] Whether it is a DC stability control system, a regional stability control system, or a power source sending-out section stability control system, it is customized and configured for the safety and stability risks in a local area of a large power grid, and focuses on solving the safety and stability risks in the local area of the power grid. One of the core problems in realizing the automatic development of the stability control strategy is how to automatically search and determine the safety and stability problems that need to be solved by the stability control system through an algorithm, thereby greatly reducing the scope of attention in the development of the stability control strategy. Therefore, the present patent proposes the concept of the key object set for stability control strategy research and a hierarchical division scheme.

[0084] The key object set for stability control strategy research is a collection of power grid analysis or control objects composed of power generation sites, DC converter stations, buses (nodes), and transmission lines. These objects collectively constitute the set of power grid equipment that the given stability control system focuses on in the research of control strategy. In some embodiments, it is also the power grid topology.

[0085] According to the different aspects of the development of the stability control strategy, the key object set is set to be composed of three hierarchical sets, which are respectively: a risk assessment object set a key section object set and a stability control object set

[0086] The risk assessment object set contains all sites (i.e., nodes in the present application) and lines that need to be focused on in the development and research of the stability control strategy. That is, the overloading of the transmission lines contained in , the voltage instability of the nodes contained in , or the synchronous instability or power oscillation of the generators contained in as the leading unstable units need to be specifically addressed by the stability control strategy. The power grid operation risks not contained in may not be included in the evaluation category of the stability control strategy.

[0087] The key section object set is composed of a plurality of transmission section subsets, and the key section object set includes an output section subset. Each transmission section subset is composed of A power transmission section is composed of one to several transmission lines. One transmission line can appear in several section subsets, but there cannot be two identical section subsets. In the process of developing the stability control strategy, only select each subset, and arbitrarily select the combination of maintenance lines and fault lines. The combination of maintenance lines and fault lines that do not belong to the section subset can not be considered.

[0088] Stability control object set It is composed of part of the power generation stations and DC converter stations in . They contain both the dominant regulation objects of the power generation mode adjustment in the stability control research and the control objects of the stability control strategy export adjustment.

[0089] Regarding the automatic search algorithm for the key object set, the present patent proposes a key object set automatic search algorithm based on breadth-first neighbor expansion and multi-head parallel recursive search.

[0090] First, the breadth-first neighbor expansion method is used to automatically search for the risk assessment object set In the development of the stability control strategy, only the security and stability risks of the objects in need to be considered.

[0091] Second, take all power plants and DC converter stations in as the starting point, and use the breadth-first method to search for transmission channels in parallel. In the search process, recursively aggregate power plants and DC converter stations, and calculate the key section discriminant M. The key section discriminant M is defined as formula (1).

[0092]

[0093] In the formula, C g is the installed capacity of the aggregated power plant / converter station associated with the section, C t is the transmission capacity of the key section, and n t is the number of transmission channels. For the generation method of the section and the aggregated power plant / converter station, see step 4.2.

[0094] If the key section meets the set conditions (see step 4.2 for details), add the corresponding power transmission section subset to the key section object set At the same time, record the power plants and DC converter stations associated with the section subset, and increase the station control degree d of the corresponding power plant and DC converter station by one.

[0095] Repeat the breadth-first search until all objects in are searched. Finally, sort by frequency from high to low to form the stability control object set ​

[0096] In the maintenance equipment and fault equipment combination in the stability control strategy formulation, only the subset of is selected for arbitrary combination. The control object in the stability control strategy formulation only needs to be optimized and screened from . The algorithm flow chart is shown in Figure 2 , and specifically, the steps include:

[0097] Step 4.1 Breadth-first neighbor expansion method determines the risk assessment object set

[0098] A core power grid node number is input for the stability control equipment type as the algorithm input (i.e. in the present application, the input power grid node is determined according to the stability control equipment type). For example, the DC stability control inputs the AC node number of the DC converter station; the power source sending or regional stability control system inputs one or more power plant high-voltage bus node numbers, etc.

[0099] Take the input node as the starting point N0, and record k=0, and search the layer limit value K, which can be usually taken as search layer limit value K=4-6.

[0100] The breadth-first search strategy is adopted, and the following steps are executed:

[0101] STEP-1: For each node in the set N k , search its first-order neighbor nodes, i.e. all nodes directly connected to it by transmission lines, and execute STEP-2;

[0102] STEP-2: Among all the searched nodes, the nodes not belonging to the set N0-N k form a set N k+1 , and STEP-3 is executed;

[0103] STEP-3 checks whether k is greater than or equal to the search layer limit value K, and whether the set contains at least one power plant node. If yes, STEP-4 is executed; if no, set k=k+1 and execute STEP-1;

[0104] STEP-4: all searched power plants, DC converter stations, transmission lines, etc. are added to the risk assessment object set

[0105] Step 4.2 Multi-head parallel recursive search forms a transmission section set

[0106] The formal description is as follows:

[0107] STEP-5: set the transmission section set to be empty, and set All the AC nodes of power plants and DC converter stations in the starting set P0. The plant and station control degree d of each plant and station node is set to 0. Start the breadth-first search. For each new node set P j , two sets of interrelated set variables are additionally set, which are the aggregation node set CL j and the aggregation power set g j corresponding to CL j .

[0108] Initialization: Set the count value j = 0, and all the AC nodes of power plants and DC converter stations in P0 are added to the aggregation node set CL0 and the aggregation power set g0. At this time, each power plant or DC converter station is regarded as an independent subset of CL0 and g0.

[0109] Start the multi-head parallel search.

[0110] STEP-6: Generate the set (corresponding to the starting set in the present application) P j+1 . In parallel, for any node a in P j (the current set), search the transmission line connected to the node a and the opposite node b. In some embodiments, the search can be performed in P . For the opposite node b, if it does not belong to P0~P j , add it to the next node set P j+1 (i.e. the second node not belonging to any of the previous sets is added to the next set); at the same time, record the first and last node pair of the corresponding transmission line into the set (i.e. the line set in the present application) L j ={L m,n}, where m lines are the nodes in P j , and n is the node in P j or P j+1 .

[0111] STEP-7: Search the key section.

[0112] For each subset element CL j in CL j,k , filter all the lines from L j in which the first end node belongs to CL j,k and the last end node does not belong to CL j,k to form a candidate section subset. Determine whether the section subset satisfies the following formula (2) or formula (3) constraint (i.e. the preset condition in the present application), and if yes, add the subset to the transmission section set At the same time, perform formula (4) operation on the plant and station control degree d of each plant and station node in g j,k .

[0113] N L≤3 (2)

[0114] M≥0 (3)

[0115] In the formula, N L is the number of outgoing lines of the node, and M is a key section determination index, as shown in formula (1).

[0116] d=d+1 (4)

[0117] STEP-8: Generating the set CL j+1 and g j+1 .

[0118] Traversing the set L j , if there are two or more (i.e., the preset number in the present application is greater than or equal to 2) aggregated node set elements CL j,k connected together through the power transmission line, these aggregated node set elements are merged into one set, and the corresponding power supply set element g j,k is also merged into one set, and the operation is repeated until no new merging occurs. The node set in P j connected to the aggregated node set node (located in the set P j+1 ) after merging is added to CL j+1 as an element (i.e., the third node in the present application).

[0119] STEP-9: Checking whether all objects in have been searched, yes, stopping the search. Otherwise, the count value j=j+1, and STEP-6 is executed.

[0120] Step 4.3: Determining the control object set

[0121] The generating stations and AC nodes of the DC converter stations in the starting point set P0 in the previous step are sorted in descending order according to their station control degrees d, and the first C generating stations and DC converter stations are added to the control object set

[0122] A specific example is described in detail as follows: the example system includes 18 nodes, 4 generating station nodes, and 2 DC converter station nodes, and the wiring diagram is shown in Figure 3 .

[0123] Figure 3 In the example, G1, G2, G3, and G4 are generating stations with capacities of 6 million, 1 million, 2 million, and 2 million kilowatts respectively, D1 and D2 are DC converter stations with capacities of 3 million kilowatts each, and the transmission capacity of each line is 2 million kilowatts. The DC stability control strategy of D1 is studied in the example. The input node is the DC converter station D1, K=4, and C=3. The automatic search calculation process is as follows:

[0124] Step 2.1 Risk assessment object set generated;

[0125] Take K = 4, and based on the strategy of breadth-first and near-neighbor expansion, the risk assessment object set is obtained by taking the DC converter station D1 as the algorithm input The flowchart of the obtaining process is shown in Figure 4 .

[0126] The arrowed line indicates that the newly searched node has been in the set and is not added repeatedly.

[0127] As can be seen from Figure 4 , the risk assessment object set is formula (5).

[0128]

[0129] Step 2.2 Power transmission section set generated;

[0130] The flowchart of the obtaining process is shown in Figure 5 , and the numbers beside the lines in the figure indicate the number of lines, wherein the arrowed line indicates that the newly searched node has been in the set and is not added repeatedly.

[0131] (STEP-5) Initialization.

[0132] All the AC nodes of the power plants and DC converter stations in are taken as the starting set P0, as shown in formula (6).

[0133] P0: {D1, G1, G3, G2, D2} (6)

[0134] The corresponding relationship between the starting aggregation node set CL0 and the corresponding power supply set g0 is shown in Table 1.

[0135]

[0136]

[0137] Table 1

[0138] 2.2.1 First execution of STEP-6;

[0139] (STEP-6) Set the next node set P1 as empty, and start to perfect the set P1. In parallel, for any node a in P0, search the power transmission lines connected to the node a and the opposite end node b.

[0140] The searched lines are L0 = {L D1 ,2, L D2 ,5, LD1 ,3,L D1 ,4,L G2 ,2,L G1 ,3,L G3 ,3,L G3 ,1,L G1 ,1,L G1 , 11}

[0141] For the opposite end node b, if it does not belong to P0, it is added to the next level node set P1.

[0142] Finally, P1 = {4, 3, 2, 1, 11, 5} is obtained.

[0143] (STEP-7) Search for key sections. Elements CL 0,i in the aggregation node set CL0 are searched in parallel 0,i If the constraint of formula (2) or formula (3) is satisfied, the power transmission line set connected with CL 0,i is recorded as a power transmission section subset, and is added to the power transmission section set At the same time, the power supply set g 0,i containing each plant node corresponding to CL 0,i is operated by formula (4). The specific calculation process is shown in Table 2.

[0144]

[0145]

[0146] Table 2

[0147] (STEP-8) Generate set CL1 and g1.

[0148] Traverse the set L0. If there are two or more aggregation node set elements CL j,k connected together through L0, these aggregation node set elements are merged into a set, and the corresponding power supply set elements g 0,k are also merged into a set (exemplarily, L(D1, 3) L(G1, 3) L(G3, 3) are searched, and CL01, CL03, and CL04 are connected; L(D1, 2) L(G2, 2) are searched, and CL02 and CL04 are connected. At this time, the four CLs are aggregated into one), and the operation is repeated until no new merging occurs. The node set in P1 connected with the merged aggregation node set node (located in set P0) is added as an element to CL1. The specific process is shown in Table 3.

[0149]

[0150] Table 3

[0151] The newly formed set of aggregate nodes CL1 = {CL 1,1 ,CL 1,2}

[0152] (STEP-9) Inspection Have all objects in the search been found? Objects that have not yet been found are:

[0153] {6,7,8,12,L 2,1 ,L 4,12 ,L 4,5 ,L 3,4 ,L 12,11 ,L 5,6 ,L 6,7 ,L 6,8}

[0154] The count value j = j + 1, and STEP-6 is executed for the second time.

[0155] 2.2.2 Perform STEP-6 for the second time;

[0156] (STEP-6) Complete set P2. For any node a in P1, search in parallel for the transmission line connected to node a and the opposite node b.

[0157] The searched route is L2 = {L 2,1 ,L 4,12 ,L 4,5 ,L 3,4 ,L 12,11 ,L 5,6}

[0158] If the peer node b does not belong to P1, then add it to the next level node set P2.

[0159] Finally, we get P2 = {12, 6}.

[0160] (STEP-7) Search for critical sections. Search in parallel for elements CL in the aggregate node set CL1. 1,i If the constraints of equation (2) or equation (3) below are satisfied, then it will be related to CL. 1,i The set of connected transmission lines is denoted as a subset of transmission sections. Adding a section to the set of transmission sections... At the same time for CL 1,i The corresponding power supply set g 1,i The plant control degree d of each plant node included is operated according to formula (4). See Table 4 for the specific process.

[0161]

[0162] Table 4

[0163] (STEP-8) Generating set CL2 and g2.

[0164] Traversing set L1, if there are two or more aggregated node set elements CL 1,k connected together through the transmission lines, these aggregated node set elements are merged into one set, and the corresponding power supply set element g 1,k is also merged into one set, and the operation is repeated until no new merging occurs. All the node sets in P1 connected to the merged aggregated node set node (in set P0) are added as elements to CL2. The specific process is shown in Table 5.

[0165]

[0166] Table 5

[0167] The new aggregated node set CL2 = {CL 2，1} is formed.

[0168] (STEP-9) Checking whether all objects in the set have been searched. The objects that have not been searched are:

[0169] {7, 8, L 6,7 , L 6,8};

[0170] The count value j = j + 1, and STEP-6 is executed for the third time.

[0171] 2.2.3 Third execution of STEP-6;

[0172] (STEP-6) Perfecting set P3. In parallel, for any node a in P2, search the transmission lines connected to the node a and the opposite end node b.

[0173] The searched lines are L3 = {L 6,7 , L 6,8}

[0174] For the opposite end node b, if it does not belong to P2, it is added to the next level node set P3.

[0175] Finally, P3 = {7, 8} is obtained.

[0176] (STEP-7) Searching key sections. In parallel, search the elements CL 2,i in the aggregated node set CL2, if the following constraints of formula (2) or formula (3) are satisfied, the set of transmission lines connected to CL 2,i is recorded as a transmission section subset, and added to the transmission section set At the same time, the corresponding power supply set g 2,i is also added to the power supply set g 2,iThe plant control degree d of each plant node included in the set P is operated according to the formula (4). The specific process is shown in Table 6.

[0177]

[0178] Table 6

[0179] (STEP-8) Generating the set CL3 and g3.

[0180] Traverse the set L3, if there are two or more than two aggregated node set elements CL 2,k connected together through the transmission line, these aggregated node set elements are merged into one set, and the corresponding power supply set element g 2,k is also merged into one set, and the operation is repeated until no new merging occurs. (No merging occurs in this operation) The set of nodes in P1 connected to the aggregated node set node (located in the set P0) after merging is added to CL3 as an element. The specific process is shown in Table 7.

[0181]

[0182] Table 7

[0183] The new aggregated node set CL3 formed is CL3={CL 3，1}.

[0184] (STEP-9) Check whether all objects in the set P have been searched. If all have been searched, the flow ends.

[0185] 2.3 Control object set is generated.

[0186] The generating plants and AC nodes of DC converter stations in the starting set P0 in the last step are sorted according to their control degree coefficients from high to low, and the final values of the plant control degree are shown in Table 8.

[0187] Plant Plant control [Gl] 3 [G2] 3 [G3] 3 [D1] 2 [D2] 2

[0188] Table 8

[0189] Therefore, if the upper limit C of the control object set set by the stability control system is 3, the first C generating plants and DC converter stations are added to the control object set , that is, the control object set is shown in formula (14).

[0190]

[0191] In conclusion, the method provided by the embodiment of the application comprises: acquiring a power grid topology and capacities of nodes; determining input power grid nodes according to a type of stability control equipment; obtaining a risk assessment object set based on the input power grid nodes and the power grid topology through a breadth-first neighbor expansion strategy; the risk assessment object set is nodes and lines included in a stability control coverage range and represents a range of attention for stability risk analysis; obtaining a key section object set based on the risk assessment object set and the capacities of the nodes through a multi-head parallel recursive search strategy; the key section object set is used to represent a range of attention for maintenance and fault setting; sorting stations according to the key section object set to determine a stability control object set; the stability control object set is used to represent a range of attention for stability control. The embodiment of the application defines the range of attention for stability risk analysis, the range of attention for maintenance and fault setting and the range of attention for stability control through the risk assessment object set, the key section object set and the stability control object set respectively, and then formulates a stability control strategy, which is beneficial to improving the efficiency of formulating the stability control strategy and the application universality.

[0192] Secondly, referring to the attached Figure 6 The embodiment of the application provides a system for searching objects of a power grid stability control strategy.

[0193] Figure 6 is a structural schematic diagram of the system for searching objects of the power grid stability control strategy according to the embodiment of the application, and the system specifically comprises:

[0194] The first module 610 is used for acquiring a power grid topology and capacities of nodes.

[0195] The second module 620 is used for determining input power grid nodes according to a type of stability control equipment.

[0196] The third module 630 is used for obtaining a risk assessment object set based on the input power grid nodes and the power grid topology through a breadth-first neighbor expansion strategy; the risk assessment object set is nodes and lines included in a stability control coverage range and represents a range of attention for stability risk analysis.

[0197] The fourth module 640 is used for obtaining a key section object set based on the risk assessment object set and the capacities of the nodes through a multi-head parallel recursive search strategy; the key section object set is used to represent a range of attention for maintenance and fault setting.

[0198] The fifth module 650 is used for sorting stations according to the key section object set to determine a stability control object set; the stability control object set is used to represent a range of attention for stability control.

[0199] It can be seen that the contents in the method embodiments are applicable to the system embodiments, the system embodiments specifically implement the functions same as the method embodiments, and achieve the beneficial effects same as the method embodiments.

[0200] Referring to Figure 7 The embodiment of the present application provides a device for searching objects for power grid stability control strategy, which comprises:

[0201] at least one processor 710;

[0202] at least one memory 720 for storing at least one program;

[0203] When the at least one program is executed by the at least one processor 710, the at least one processor 710 implements the method for searching objects for power grid stability control strategy.

[0204] Similarly, the contents in the method embodiments are applicable to the device embodiments, the device embodiments specifically implement the functions same as the method embodiments, and achieve the beneficial effects same as the method embodiments.

[0205] The embodiment of the present application further provides a computer readable storage medium, wherein a program executable by a processor is stored, and the program executable by the processor is used for executing the method for searching objects for power grid stability control strategy when executed by the processor.

[0206] Similarly, the contents in the method embodiments are applicable to the storage medium embodiments, the storage medium embodiments specifically implement the functions same as the method embodiments, and achieve the beneficial effects same as the method embodiments.

[0207] In some alternative embodiments, the functions / operations mentioned in the block diagram can not occur in the order mentioned in the operation diagram. For example, two blocks shown in succession can actually be executed substantially simultaneously or the blocks can sometimes be executed in reverse order, depending on the functions / operations involved. In addition, the embodiments presented and described in the flowcharts of the present application are provided by way of example, with the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and in which sub-operations described as part of larger operations are independently executed.

[0208] Furthermore, although the present application is described in the context of functional modules, it is to be understood that one or more of the functions and / or features can be integrated in a single physical device and / or software module, or one or more functions and / or features can be implemented in separate physical devices or software modules. It will also be appreciated that detailed discussion of the actual implementation of each module is not necessary to an understanding of the application. Rather, the actual implementation of the modules, in light of the attributes, functions and internal relationships of the various functional modules disclosed herein, will be apparent to one of ordinary skill in the art given the benefit of this disclosure. Accordingly, the present application is not limited to the specific embodiments illustrated herein, but is applicable for use in general with any device or system that has the functionality of the modules disclosed herein. It will also be appreciated that the particular conceptualization disclosed herein is merely an example, and is not intended to limit the scope of the application, which is defined by the appended claims and their equivalents.

[0209] If the functions are implemented in software, the functions can be stored in or implemented as one or more computer program products, which can be incorporated into a computer-readable medium for use by or in connection with an apparatus, method, or system as described herein. The computer-readable medium carries a computer program or processor-executable instructions that can be accessed by a computer. The computer-readable medium can be a computer- readable storage medium or a computer-readable signal medium.

[0210] Logic and / or steps represented in flow diagrams or otherwise described herein, for example, can be embodied in computer-readable instructions, processes, or program code, or in any other form that can be implemented by a program execution system, apparatus, or device, such as a computer-based system, system on a chip, or other system that can fetch instructions from a program execution system, apparatus, or device and execute the instructions. For purposes of this specification, a "computer-readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the program execution system, apparatus, or device.

[0211] More specific examples (a non-exhaustive list) of the computer-readable medium include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can also be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, for example, via optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.

[0212] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the above described embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable

[0213] In the above description of the present application, reference has been made to descriptive terms such as "one embodiment," "another embodiment," "some embodiments," etc. Such descriptive terms mean that a particular feature, structure, material or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily referring to the same embodiment. Further, when a particular feature, structure, material or characteristic is described in connection with any one or more embodiments, it is submitted that it is within the purview of the inventor(s) to effect such feature, structure, material or characteristic in connection with any other or all embodiments.

[0214] While the embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, combinations, and alterations can be made to the embodiments without departing from the spirit and scope of the present application, which is defined by the appended claims and their equivalents.

[0215] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the above-described embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present application, and these equivalent modifications or substitutions are included in the scope of the present application defined by the claims.

Claims

1. A method for object search for power grid stability control strategy, characterized in that, The method comprises the following steps: obtaining a power grid topology and capacities of nodes; determining an input power grid node according to a type of a stability control device; obtaining a risk assessment object set through a breadth-first near neighbor expansion strategy based on the input power grid node and the power grid topology; the risk assessment object set is a node or a line included in a stability control coverage range and represents a range of concern for stability risk analysis; determining a starting point set, an aggregated node set and a power supply set according to the risk assessment object set; the aggregated node set and the power supply set correspond to each other; adding a second node not belonging to any previous set to a next set by searching for a line connected to a node in a current set and its opposite end second node, and determining a line set; adding a line in the line set, whose first end node belongs to a previous aggregated node set and whose last end node does not belong to the previous aggregated node set, to a candidate section subset; determining whether to add the candidate section subset to a key section object set based on a key section discrimination index according to the capacities of the nodes and the lines in the candidate section subset; aggregating a new aggregated node set and a power supply set by traversing the line set; the key section object set is used to represent a range of concern for maintenance and fault setting; sorting stations according to the key section object set to determine a stability control object set; the stability control object set is used to represent a range of concern for stability control. 2.The object search method for grid stability control strategy according to claim 1, characterized in that, The method of obtaining the risk assessment object set based on the input power grid node and the power grid topology through the breadth-first near neighbor expansion strategy comprises the following steps: determining a first-order node adjacent to the input power grid node; if a search layer number does not reach a preset layer number, determining a next-order node adjacent to a current-order node until the search layer number reaches the preset layer number, and screening out repeated nodes and lines to obtain the risk assessment object set. 3.The object search method for grid stability control strategy according to claim 1, wherein, The method of determining whether to add the candidate section subset to the key section object set based on the key section discrimination index according to the capacities of the nodes and the lines in the candidate section subset comprises the following steps: determining a key section discrimination index according to installed capacities of nodes in the candidate section subset, a power transmission capacity of the candidate section subset and a power transmission channel of the candidate section subset; if the key section discrimination index meets a preset condition, adding the candidate section subset to the key section object set.

4. The object search method for power grid stability control strategy according to claim 1, characterized in that, The method of aggregating a new aggregated node set and a power supply set by traversing the line set comprises the following steps: if there are a preset number of aggregated node set elements connected through lines in the line set, merging the aggregated node set elements; if a third node is connected to the merged aggregated node set elements and belongs to a next set, adding the third node to a new aggregated node set and generating a corresponding new power supply set.

5. The object search method for power grid stability control strategy according to claim 1, characterized in that, The method of sorting stations according to the key section object set to determine a stability control object set comprises the following steps: if the candidate section subset is added to the key section object set, updating a control degree of a node related to the candidate section subset. All nodes of the power grid are sorted in descending or ascending order according to the control degree, and a number of nodes are screened to obtain a stable control object set.

6. An object search system for grid stability control strategy, characterized by, The method comprises the following steps: A first module is configured to acquire a power grid topology and capacities of nodes; A second module is configured to determine input power grid nodes according to a type of a stability control device; A third module is configured to obtain a risk assessment object set by a breadth-first neighbor expansion strategy based on the input power grid nodes and the power grid topology, wherein the risk assessment object set represents a range of concern for stability risk analysis and comprises nodes and lines covered by the stability control device; A fourth module is configured to determine a starting point set, an aggregated node set and a power supply set according to the risk assessment object set; The aggregated node set and the power supply set correspond to each other; Second nodes connected to nodes in a current set are searched in parallel, and the second nodes not belonging to any set in a previous sequence are added to a next set, and a line set is determined; lines in the line set, of which a first end node belongs to a previous aggregated node set and a last end node does not belong to the previous aggregated node set, are added to a candidate section subset; Based on a key section judgment index, it is determined whether to add the candidate section subset to a key section object set according to the capacities of the related nodes in the candidate section subset and the lines; the line set is traversed, and a new aggregated node set and a power supply set are aggregated; The key section object set is used to represent a range of concern for maintenance and fault setting; A fifth module is configured to sort stations according to the key section object set and determine a stable control object set, wherein the stable control object set is used to represent a range of concern for stability control.

7. An object search device for a power grid stability control strategy, characterized by, The method comprises the following steps: At least one processor; At least one memory configured to store at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the object search method for a power grid stability control strategy according to any one of claims 1 to 5.

8. A computer readable storage medium having stored therein a program which is executable by a processor, characterized in that, The program executable by the processor is used to implement the object search method for the power grid stability control strategy according to any one of claims 1 to 5 when the program is executed by the processor.

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