A regional power grid passive isolated network fast discrimination method

Abstract

The application discloses a kind of regional power grid passive isolated network fast discrimination method, it is related to electric power technical field, it is suitable for the isolated network discrimination of new energy plant station or industrial and mining enterprise power grid through core substation grid connection, comprising: according to the networking path of large power grid access line and regional power grid grid connection line, define key element and key circuit breaker;Five key circuit breaker groups are defined by key element;The position signal of each key circuit breaker and the voltage and frequency of regional power grid grid connection line are collected;According to the number of each group key circuit breaker and isolated network starting value, determine whether isolated network starts;After determining isolated network starts, according to grid connection line voltage and frequency and isolated network delay value, determine whether regional power grid is isolated network.This method comprehensively switch quantity and electrical quantity are carried out regional power grid isolated network discrimination, can effectively avoid the misjudgment caused by switch position anomaly.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method for rapid identification of passive islanded grids in regional power grids. Background Technology

[0002] With the rapid development of new energy technologies, the number of regional power grids, represented by power grids for new energy plants and industrial and mining enterprises, is constantly increasing. The stable operation of regional power grids is a fundamental condition for ensuring the absorption capacity of new energy sources or the normal production activities of enterprises within their jurisdiction. However, regional power grids face the risk of becoming isolated grids, threatening their safe and stable operation. Isolated grid identification technology is the foundation for the prevention and control of isolated grids in regional power grids, and it has significant economic and social benefits for improving the safe and stable operation of regional power grids.

[0003] Relying on manual analysis to identify isolated networks is labor-intensive and difficult to cover all isolated network scenarios, which can easily lead to inaccurate judgments. Therefore, there is a need to provide a rapid and automatic identification technology for isolated networks in regional power grids. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or existing methods for rapid identification of passive islanded networks in regional power grids, this invention is proposed.

[0006] Therefore, the problem to be solved by this invention is to provide a method for rapid identification of passive islanded grids in a regional power grid.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for rapid identification of passive islanded grids in a regional power grid, comprising defining key components and key circuit breakers for the interconnection paths of the large power grid access lines and regional power grid connection lines within the core substation;

[0008] Five critical circuit breaker groups are defined by each critical circuit breaker;

[0009] Collect the location signals of each key circuit breaker in the core substation, as well as the voltage and frequency of the grid-connected lines of the regional power grid;

[0010] Determine whether the island network needs to be activated based on the number of critical circuit breakers in each group and the island network start-up setting.

[0011] After the isolated grid is started, the regional power grid is determined to be isolated based on the grid-connected line voltage and frequency, as well as the isolated grid delay setting.

[0012] As a preferred embodiment of the method for rapid identification of passive isolated grids in a regional power grid as described in this invention, the network path refers to all possible paths from any access line of the large power grid to any grid-connected line of the regional power grid, provided that each element in the path is passed only once. Each element in the path includes each bus section, circuit breaker, and main transformer.

[0013] The key components include each component in the network path, which is defined as a key component, and the key components are used to identify isolated networks.

[0014] The critical circuit breaker includes the circuit breaker in the critical components, which is defined as the critical circuit breaker.

[0015] As a preferred embodiment of the method for rapid identification of passive islanded grids in a regional power grid as described in this invention, the five key circuit breaker groups include: access-side circuit breaker, access-side bus circuit breaker, main transformer circuit breaker, grid-connected bus circuit breaker, and grid-connected circuit breaker.

[0016] As a preferred embodiment of the method for rapid identification of passive isolated grids in a regional power grid as described in this invention, the access-side circuit breaker includes a set of key circuit breakers between the large power grid access line and the substation bus section.

[0017] The access-side bus circuit breaker includes a set of key circuit breakers between each bus section on the access side of the large power grid within the core substation and between each access-side bus section and the main transformer.

[0018] The main transformer circuit breaker includes a set of circuit breakers between the main transformer and the bus section of the grid connection side of the large power grid or the grid connection side of the regional power grid.

[0019] The grid-connected busbar circuit breaker includes a set of key circuit breakers between each busbar segment on the grid-connected side of the regional power grid within the core substation and between each grid-connected busbar segment and the main transformer.

[0020] The grid-connected circuit breaker includes a set of key circuit breakers between the regional power grid grid connection line and the substation busbar.

[0021] As a preferred embodiment of the method for rapid identification of passive islanded grids in a regional power grid as described in this invention, the position signal of the critical circuit breaker includes: when at least two of the three-phase position signals of the critical circuit breaker are HWJ=1 or TWJ=0, the critical circuit breaker is determined to be in the closed position; otherwise, the critical circuit breaker is determined to be in the open position.

[0022] The voltage and frequency of the regional power grid connection lines include the average value of the median three-phase voltage of each connection line for voltage and the average value of the frequency of each connection line for frequency.

[0023] As a preferred embodiment of the method for rapid identification of passive isolated grid in regional power grid according to the present invention, the method is as follows: the number of key circuit breakers in each group is counted based on the opening status of each key circuit breaker; when the number of key circuit breakers in any group reaches the isolated grid start-up set value corresponding to that group, the regional power grid is determined to be in isolated grid start-up; otherwise, the isolated grid is determined not to be initiated.

[0024] The corresponding islanded grid start-up setting value for the circuit breaker group on the access side is the number of large grid access lines L. J That is, when the number of circuit breakers on the connected side reaches L J Timely determination of isolated network startup;

[0025] The islanded start-up setting value corresponding to the group of circuit breakers connected to the access side busbar is the minimum value D among the number of circuit breakers connected to the access side busbar in each access busbar section. J That is, when the number of circuit breakers on the access side bus reaches D J The system determines when an isolated grid will start; the access bus section is defined as a bus section within the core substation that is directly connected to the main power grid access line via a key circuit breaker.

[0026] The islanding start setting corresponding to the main transformer circuit breaker group is the number of main transformers T between the access side bus and the grid-connected side bus. That is, when the number of main transformer circuit breakers that have broken reaches T, islanding start is determined.

[0027] The islanded start-up setting value corresponding to the group of circuit breakers on the grid-connected side is the minimum value D among the number of circuit breakers on the grid-connected side connected to each grid-connected bus section. b That is, when the number of circuit breakers on the grid-connected bus reaches D b The system determines when an isolated grid will start; the grid-connected bus section is defined as the bus section within the core substation that is directly connected to the regional power grid grid-connected line via a key circuit breaker;

[0028] The corresponding islanded grid start-up setting value for the circuit breaker group on the grid-connected side is the number of grid-connected lines in the regional power grid, L. b That is, when the number of circuit breakers on the grid-connected side reaches L b The isolated network is determined to start at that time.

[0029] As a preferred embodiment of the method for rapid identification of passive islanding in a regional power grid as described in this invention, the method is as follows: when the regional power grid is islanded, if the voltage or frequency of the grid-connected lines exceeds the islanded voltage setting or islanded frequency setting and remains so after the islanded delay setting time, the regional power grid is determined to be islanded; otherwise, the regional power grid is determined to be non-islanded. When the regional power grid is not islanded, if the voltage or frequency of the grid-connected lines exceeds the islanded voltage setting or islanded frequency setting, the regional power grid voltage or frequency is determined to be abnormal.

[0030] As a preferred embodiment of the method for rapid identification of passive islanded grids in a regional power grid according to the present invention, the islanded grid voltage setting includes an upper limit value U for the islanded grid voltage.gh And the lower limit of the isolated grid voltage U gl When the grid connection line voltage is higher than U gh or below U gl When determining voltage islanding;

[0031] The isolated network frequency setting includes an upper limit value f for the isolated network frequency. gh and the lower limit of the frequency of the isolated network f gl When the frequency of the grid connection line is higher than f gh or below f gl Time-based determination of frequency isolated networks;

[0032] When an isolated grid is started, if it simultaneously meets either the voltage isolated grid or the frequency isolated grid condition and remains so for a time interval t, then the regional power grid is determined to be an isolated grid; otherwise, the regional power grid is determined to be a non-isolated grid.

[0033] If the regional power grid is not isolated and meets the requirements of voltage isolation or frequency isolation, then the regional power grid is determined to be abnormal in voltage or frequency.

[0034] A computer device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the method described above.

[0035] A computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the steps of the method described above.

[0036] The beneficial effect of this invention is that this method integrates switching quantities and electrical quantities to identify isolated networks in regional power grids, which can effectively avoid misjudgments caused by abnormal switch positions. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0038] Figure 1 This is a flowchart illustrating a method for rapid identification of passive isolated networks in a regional power grid, as described in Example 1.

[0039] Figure 2 This is a logic block diagram of the criteria for a method for rapid identification of passive isolated networks in a regional power grid, as shown in Example 1.

[0040] Figure 3 This is an electrical system connection diagram of a method for rapid identification of passive isolated networks in a regional power grid, as described in Example 3.

[0041] Figure 4 This refers to all possible interconnection paths between the large power grid access line and the regional power grid grid connection line in the fast identification method for passive isolated grids of a regional power grid in Example 3.

[0042] Figure 5 This is a schematic diagram showing the relative positions of five key circuit breakers in a method for rapid identification of passive isolated grids in a regional power grid, as described in Example 3.

[0043] Figure 6 This is an electrical system connection diagram of a method for rapid identification of passive islanded grids in a regional power grid, as shown in Example 4. Detailed Implementation

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0046] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0047] Example 1

[0048] like Figure 1 and Figure 2 This is the first embodiment of the present invention, which provides a method for rapid identification of passive islanded grids in a regional power grid, including...

[0049] Step 1: Define the components on the connection paths of the main power grid access lines and regional power grid connection lines within the core substation as critical components, and define the circuit breakers among the critical components as critical circuit breakers. Subsequent methods are limited to using critical components for islanded network identification.

[0050] Step 2: Define five key circuit breaker groups: access side circuit breaker, access side bus circuit breaker, main transformer circuit breaker, regional power grid connection bus circuit breaker, and regional power grid connection circuit breaker.

[0051] Step 3: Collect the location signals of each key circuit breaker in the core substation, as well as the voltage and frequency of the regional power grid connection lines.

[0052] Step 4: Calculate the number of critical circuit breakers broken in each group based on their breaking status. When the number of critical circuit breakers broken in any group reaches the islanding start-up setting for that group, the regional power grid is determined to be islanded; otherwise, it is determined that the islanding is not started.

[0053] Step 5: When the regional power grid starts to be isolated, if the voltage or frequency of the regional power grid's grid-connected lines exceeds the isolated grid voltage setting or isolated grid frequency setting and remains so after the isolated grid delay setting time, the regional power grid is determined to be isolated; otherwise, the regional power grid is determined to be non-isolated.

[0054] like Figure 1 The diagram illustrates a method for rapid identification of passively isolated regional power grids proposed in this invention. This method is applicable to the identification of isolated power grids in new energy plants or industrial and mining enterprises connected to the grid via core substations. When a critical component within the core substation fails, the regional power grid, represented by new energy plants or industrial and mining enterprise power grids, may lose its electrical connection with the main power grid and passively enter an isolated operating state. The method proposed in this invention can effectively identify the isolated state of the regional power grid under such circumstances. The overall logic diagram for isolated grid identification is shown below. Figure 2 As shown.

[0055] In step one, the network path refers to all possible paths from any access line of the large power grid to any grid-connected line of the regional power grid, provided that each element in the path is passed only once. Each element in the path includes each bus section, circuit breaker, and main transformer.

[0056] The key components include each component in the network path, which is defined as a key component, and the circuit breaker among the key components is defined as a key circuit breaker.

[0057] In step two, the access-side circuit breaker refers to the set of key circuit breakers between the large power grid access line and the substation bus section.

[0058] The access-side busbar circuit breaker refers to the set of key circuit breakers between each busbar section on the access side of the large power grid within the core substation, and between each access-side busbar section and the main transformer.

[0059] The main transformer circuit breaker refers to the set of circuit breakers between the main transformer and the bus section of the main power grid connection side or the regional power grid connection side.

[0060] The grid-connected busbar circuit breaker refers to the set of key circuit breakers between each busbar section on the grid-connected side of the regional power grid within the core substation, and between each grid-connected busbar section and the main transformer.

[0061] The grid-connected circuit breaker refers to the set of key circuit breakers between the grid-connected lines of a regional power grid and the substation busbar.

[0062] In step three, the critical circuit breaker is determined to be in the closed position when at least two of the three-phase position signals of the critical circuit breaker are HWJ=1 or TWJ=0; otherwise, the critical circuit breaker is determined to be in the open position.

[0063] The voltage of the grid-connected lines in the regional power grid is the average value of the median three-phase voltage of each grid-connected line, and the frequency is the average value of the frequency of each grid-connected line.

[0064] In step four, the islanded grid start-up setting corresponding to the circuit breaker group on the access side is the number of large grid access lines L. J That is, when the number of circuit breakers on the connected side reaches L J Timely determination of isolated network startup;

[0065] The islanded start-up setting value corresponding to the group of circuit breakers connected to the access side busbar is the minimum value D among the number of circuit breakers connected to the access side busbar in each access busbar section. J That is, when the number of circuit breakers on the access side bus reaches D J The system determines when an isolated grid will start. The access bus section is defined as the bus section within the core substation that is directly connected to the main power grid access line via a key circuit breaker.

[0066] The islanding start setting corresponding to the main transformer circuit breaker group is the number of main transformers T between the access side bus and the grid-connected side bus. That is, when the number of main transformer circuit breakers that have broken reaches T, islanding start is determined.

[0067] The islanded start-up setting value corresponding to the group of circuit breakers on the grid-connected side is the minimum value D among the number of circuit breakers on the grid-connected side connected to each grid-connected bus section. b That is, when the number of circuit breakers on the grid-connected bus reaches D b The system determines when an isolated grid will start; the grid-connected bus section is defined as the bus section within the core substation that is directly connected to the regional power grid grid-connected line via a key circuit breaker.

[0068] The corresponding islanded grid start-up setting value for the circuit breaker group on the grid-connected side is the number of grid-connected lines in the regional power grid, L. b That is, when the number of circuit breakers on the grid-connected side reaches L b The isolated network is determined to start at that time.

[0069] In step five, the island voltage setting includes the upper limit value U of the island voltage. gh And the lower limit of the isolated grid voltage U gl When the grid connection line voltage is higher than U gh or below U gl The voltage is isolated at that time.

[0070] The isolated network frequency setting includes an upper limit value f for the isolated network frequency. gh and the lower limit of the frequency of the isolated network f gl When the frequency of the grid connection line is higher than f gh or below fgl Time-based determination of frequency isolated networks.

[0071] When an isolated grid is initiated, if it simultaneously meets either the voltage isolated grid or the frequency isolated grid condition and remains so for a time interval t, then the regional power grid is determined to be an isolated grid; otherwise, the regional power grid is determined to be a non-isolated grid.

[0072] If the regional power grid is not isolated and meets the requirements of voltage isolation or frequency isolation, then the regional power grid is determined to be abnormal in voltage or frequency.

[0073] Example 2

[0074] The second embodiment of the present invention differs from the first embodiment in that it further includes:

[0075] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0076] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0077] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0078] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0079] Example 3

[0080] Reference Figures 3-5 This is the third embodiment of the present invention, which differs from the first two embodiments in that:

[0081] like Figure 3 As shown, the 110kV I and 110kV II busbars on the main grid access side of the core substation are connected via sectionalizing circuit breakers. On the regional grid connection side, the 35kV I and 35kV II busbars are connected via sectionalizing circuit breakers. The 35kV III busbar is not connected to either the 35kV I or 35kV II busbars. The 110kV I and 110kV II busbars are connected to the 35kV I and 35kV II busbars respectively via main transformers #1 and #2. The 110kV II busbar is also connected to the 35kV III busbar via main transformer #3. Main grid access lines 1 and 2 are connected to the 110kV I and 110kV II busbars respectively, and the regional grid connection lines are connected to the 35kV I busbar. For ease of description below, ... Figure 3 The power system circuit breaker shown is... Numbering is performed. The method for identifying isolated power grids includes the following steps:

[0082] S1, such as Figure 4 The diagram illustrates all possible interconnection paths between large power grid connection lines and regional power grid connection lines in the power system. Key components on all possible interconnection paths include circuit breakers ①, ②, ③, ④, ⑤, ⑦, ⑧, and ⑩. 110kV Bus I, 110kV Bus II, 35kV Bus I, 35kV Bus II, Main Transformer #1, Main Transformer #2. Circuit Breakers ①, ②, ③, ④, ⑤, ⑦, ⑧, ⑩. This is a critical circuit breaker. The following method will only utilize the aforementioned critical components for islanding identification. Figure 3 Circuit breakers ⑥ and ⑨, main transformer #3, and the 35kV III bus are not on the grid connection path of the main power grid connection line and the regional power grid connection line, so they are not critical components.

[0083] S2. Define the five key circuit breaker groups as follows: Connecting-side circuit breakers include circuit breakers ① and ②; connecting-side bus circuit breakers include circuit breakers ③, ④, and ⑤; main transformer circuit breakers include circuit breakers ④, ⑤, ⑦, and ⑧; regional power grid connection bus circuit breakers include circuit breakers ⑦, ⑧, and ⑩; regional power grid connection circuit breakers include circuit breakers ⑦, ⑧, and ⑩.

[0084] S3. Collect data on key circuit breakers—circuit breakers ①, ②, ③, ④, ⑤, ⑦, ⑧, and ⑩. The HWJ or TWJ signal. Acquisition of the regional power grid's connected lines—circuit breakers. The voltage and frequency on the grid-connected side.

[0085] S4. Calculate the number of critical circuit breakers broken in each group based on their breaking status. In this example, circuit breakers ③ and ⑥ are broken, and the remaining circuit breakers are closed. The number of circuit breakers broken on the access side is 0; the number of circuit breakers broken on the access side busbar is 1; the number of circuit breakers broken on the main transformer is 0; the number of circuit breakers broken on the regional power grid connection busbar is 0; and the number of circuit breakers broken on the regional power grid connection is 0.

[0086] Further, the islanding activation status is determined based on the islanding activation settings corresponding to each key circuit breaker group. The islanding activation setting L corresponding to the circuit breaker group on the access side is... J L represents the number of lines connected to the large power grid, in this example. J The value is 2. Therefore, in this example, the number of circuit breakers interrupted on the connected side is "0", which does not reach L. J .

[0087] The islanded start setting D corresponding to the circuit breaker group on the access side busbar J This is the minimum number of busbar circuit breakers connected to each access busbar section. The access busbar section is defined as a busbar section within the core substation that is directly connected to the main power grid access line via a key circuit breaker. In this example, the access busbar sections are 110kV Bus I and 110kV Bus II. In this example, D... J The minimum number of circuit breakers connected to the 110kV I bus and 110kV II bus on the access side is 2 (circuit breakers ③④ and ③⑤, respectively, with a minimum of 2). Therefore, in this example, the number of circuit breakers interrupted on the access side bus is "1", which does not reach D. J .

[0088] The main transformer circuit breaker group corresponds to the islanded network start setting T, which is the main variable between the access side bus and the grid-connected side bus. In this example, T is 2, so the number of main transformer circuit breakers interrupted in this example is "0", which does not reach T.

[0089] The corresponding islanded start setting D for the bus circuit breaker group on the grid-connected side b This is the minimum number of circuit breakers connected to the grid-connected busbar sections in each busbar section. A grid-connected busbar section is defined as a busbar section within the core substation that is directly connected to the regional power grid grid line via a key circuit breaker. In this example, the grid-connected busbar section is a 35kV I busbar. In this example, D... b The minimum number of circuit breakers on the grid-connected busbar connected to the 35kV I bus is 2 (circuit breakers ⑦ and ⑩, with a minimum quantity of 2). Therefore, in this example, the number of circuit breakers interrupted on the grid-connected busbar is "0", which does not meet the requirement of D. b ;

[0090] The corresponding islanded start setting L for the circuit breaker group on the grid-connected side b L represents the number of grid-connected lines in the regional power grid, in this example. b The number of circuit breakers interrupted on the grid-connected side is "0", which does not reach L. b ;

[0091] The number of breaks by all five sets of key circuit breakers is less than the corresponding islanding start setting, so the islanding is determined not to start.

[0092] S5. Under the condition that the islanded grid does not start, determine whether the voltage of the grid-connected line of the regional power grid is higher than the upper limit of the islanded grid voltage or lower than the lower limit of the islanded grid voltage, or whether the frequency is higher than the upper limit of the islanded grid frequency or lower than the lower limit of the islanded grid frequency. In this example, the voltage of the grid-connected line of the regional power grid is lower than the lower limit of the islanded grid voltage, and the frequency of the grid-connected line does not exceed the upper and lower limits of the islanded grid frequency, so the voltage of the regional power grid is determined to be abnormal.

[0093] Example 4

[0094] Reference Figure 6 This is the fourth embodiment of the present invention, which differs from the previous three embodiments in that:

[0095] like Figure 6 As shown, the core substation's 220kV busbar structure for connection to the main power grid is a double-bus, double-section structure, while the 110kV busbar structure for connection to the regional power grid is a double-bus, single-section structure. The 220kV IA and 220kV IIA buses are connected to the 110kV IA and 110kV II buses via main transformer #1, and the 220kV IB and 220kV IIB buses are connected to the 110kV IB and 110kV II buses via main transformer #2. Main power grid connection lines are connected to the 220kV IB and 220kV IIB buses, while regional power grid connection lines are connected to the 110kV IA and 110kV II buses. For ease of description below, [the following text is omitted as it is not part of the main text]. Figure 6The power system circuit breaker shown is... Numbering is performed. The method for identifying isolated power grids includes the following steps:

[0096] Step 1: Traversal Figure 6 All possible interconnection paths between large power grid access lines and regional power grid connection lines in the central power system. Key components on all possible interconnection paths include circuit breakers ①, ②, ③, ④, ⑤, ⑥, ⑦, ⑧, ⑨, and ⑩. 220kV IA bus, 220kV IB bus, 220kV IIA bus, 220kV IIB bus, 110kV IA bus, 110kV IB bus, 110kV II bus, Main transformer #1, Main transformer #2. Circuit breakers ①, ②, ③, ④, ⑤, ⑥, ⑦, ⑧, ⑨, ⑩. This is a critical circuit breaker. The following method will only utilize the aforementioned critical components for islanding identification.

[0097] Step 2: Define the five key circuit breaker groups as follows: Connecting-side circuit breakers include circuit breaker ①; connecting-side busbar circuit breakers include circuit breakers ②, ③, ④, ⑤, ⑥, and ⑦; main transformer circuit breakers include circuit breakers ⑥, ⑦, ⑧, and ⑨; regional power grid connection busbar circuit breakers include circuit breakers ⑧, ⑨, and ⑩. Regional power grid circuit breakers include circuit breakers

[0098] Step 3: Collect data on key circuit breakers—Circuit Breakers ①, ②, ③, ④, ⑤, ⑥, ⑦, ⑧, ⑨, ⑩. The HWJ or TWJ signal. Acquisition of the regional power grid's connected lines—circuit breakers. The voltage and frequency on the grid-connected side.

[0099] Step 4: Calculate the number of critical circuit breakers broken in each group based on their operation status. In this example, circuit breakers ⑥ and ⑦ are broken, and the remaining circuit breakers are closed. The number of circuit breakers broken on the access side is 0; the number of circuit breakers broken on the access side busbar is 2; the number of circuit breakers broken on the main transformer is 2; the number of circuit breakers broken on the regional power grid connection busbar is 0; and the number of circuit breakers broken on the regional power grid connection is 0.

[0100] Further, the islanding activation status is determined based on the islanding activation settings corresponding to each key circuit breaker group. The islanding activation setting L corresponding to the circuit breaker group on the access side is... J L represents the number of lines connected to the large power grid, in this example. J The value is 1. Therefore, in this example, the number of circuit breakers interrupted on the connected side is "0", which does not reach L. J .

[0101] The islanded start setting D corresponding to the circuit breaker group on the access side busbar JThis is the minimum number of busbar circuit breakers connected to each access busbar section. The access busbar section is defined as a busbar section within the core substation that is directly connected to the main power grid access line via a key circuit breaker. In this example, the access busbar sections are the 220kV IIB bus and the 220kV IIB bus. In this example, D... J The minimum number of circuit breakers connected to the 220kV IIB bus and the 220kV IIB bus is 3 (circuit breakers ②⑤⑦ and ④⑤⑦ are connected to the access side bus respectively, and the minimum number of both is 3). Therefore, in this example, the number of circuit breakers interrupted on the access side bus is "2", which does not reach D. J .

[0102] The main transformer circuit breaker group corresponds to the islanded network start setting T, which is the main variable between the access side bus and the grid-connected side bus. In this example, T is 2, so the number of main transformer circuit breakers to break in this example is "2" to reach T.

[0103] The corresponding islanded start setting D for the bus circuit breaker group on the grid-connected side b This is the minimum number of circuit breakers connected to the grid-connected busbar sections in each busbar segment. A grid-connected busbar segment is defined as a busbar segment within the core substation that is directly connected to the regional power grid's grid-connected lines via a key circuit breaker. In this example, the grid-connected busbar segments are the 110kV IA busbar and the 110kV Ⅱ busbar. In this example, D... b The circuit breakers on the grid-connected busbars connected to the 3 (110kV IA bus and 110kV Ⅱ bus) are circuit breakers. and ⑧, ⑨, The minimum number is 3). Therefore, in this example, the number of circuit breakers interrupted on the grid-connected busbar is "0", which does not meet the minimum requirement D. b ;

[0104] The corresponding islanded start setting L for the circuit breaker group on the grid-connected side b L represents the number of grid-connected lines in the regional power grid, in this example. b The number of circuit breakers interrupted on the grid-connected side is "0", which does not reach L. b ;

[0105] If the number of circuit breakers in the main transformer among the five key circuit breakers reaches the corresponding islanding start setting, islanding start is determined.

[0106] Step 5: After the isolated grid is activated, determine whether the voltage of the regional power grid's connected lines is higher than the upper limit of the isolated grid voltage or lower than the lower limit of the isolated grid voltage, or whether the frequency is higher than the upper limit of the isolated grid frequency or lower than the lower limit of the isolated grid frequency. In this example, the voltage of the regional power grid's connected lines is lower than the lower limit of the isolated grid voltage, and the frequency of the connected lines is lower than the lower limit of the isolated grid frequency. The isolated grid is thus determined.

[0107] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for rapid identification of passive islanded networks in a regional power grid, characterized in that: include, Define key components and key circuit breakers for the interconnection paths of the main power grid access lines and regional power grid connection lines within the core substation. Five critical circuit breaker groups are defined by each critical circuit breaker; Collect the location signals of each key circuit breaker in the core substation, as well as the voltage and frequency of the grid-connected lines of the regional power grid; Determine whether the island network needs to be activated based on the number of critical circuit breakers in each group and the island network start-up setting. After the islanded grid is started, the regional power grid is determined to be an islanded grid based on the grid-connected line voltage and frequency, as well as the islanded grid delay setting. The network path refers to all possible paths from any access line of the large power grid to any grid-connected line of the regional power grid, provided that each element in the path is passed only once. Each element in the path includes each bus section, circuit breaker, and main transformer. The key components include each component in the network path, which is defined as a key component, and the key components are used to identify isolated networks. The critical circuit breaker includes, in which the circuit breaker in the critical components is defined as a critical circuit breaker; The position signal of the critical circuit breaker includes the following: when at least two of the three-phase position signals of the critical circuit breaker are HWJ=1 or TWJ=0, the critical circuit breaker is determined to be in the closed position; otherwise, the critical circuit breaker is determined to be in the open position. The voltage and frequency of the regional power grid connection lines include the average value of the median three-phase voltage of each connection line for voltage, and the average value of the frequency of each connection line for frequency. Based on the opening status of each key circuit breaker, the number of key circuit breakers opened in each group is counted. When the number of key circuit breakers opened in any group reaches the islanding start-up setting value corresponding to that group, the regional power grid is determined to be islanding started; otherwise, the islanding is determined not to be started. The number of lines connected to the main power grid corresponds to the islanded grid start-up setting of the circuit breaker group on the access side. L J That is, when the number of circuit breakers on the access side reaches L J Timely determination of isolated network startup; The islanded start-up setting value corresponding to the circuit breaker group on the access side is the minimum value among the number of circuit breakers on the access side connected to each access bus section. D J That is, when the number of circuit breakers on the access side bus reaches D J The system determines when an isolated grid will start; the access bus section is defined as a bus section within the core substation that is directly connected to the main power grid access line via a key circuit breaker. The main transformer circuit breaker group corresponding to the islanded grid start-up setting is the number of main transformers between the access side bus and the grid-connected side bus. T That is, when the number of circuit breakers interrupted by the main transformer reaches T Timely determination of isolated network startup; The islanded start-up setting value corresponding to the group of circuit breakers on the grid-connected side is the minimum value among the number of circuit breakers on the grid-connected side connected to each section of the grid-connected bus. D b That is, when the number of circuit breakers on the grid-connected bus reaches D b The system determines when an isolated grid will start; the grid-connected bus section is defined as the bus section within the core substation that is directly connected to the regional power grid grid-connected line via a key circuit breaker; The number of grid-connected circuit breaker groups corresponding to the islanded grid start-up setting value is the number of grid-connected lines in the regional power grid. L b That is, when the number of circuit breakers on the grid-connected side reaches L b Timely determination of isolated network startup; The five key circuit breaker groups include: access-side circuit breaker, access-side bus circuit breaker, main transformer circuit breaker, grid-connected bus circuit breaker, and grid-connected circuit breaker. The access-side circuit breaker includes a set of key circuit breakers between the large power grid access line and the substation bus section. The access-side bus circuit breaker includes a set of key circuit breakers between each bus section on the access side of the large power grid within the core substation and between each access-side bus section and the main transformer. The main transformer circuit breaker includes a set of circuit breakers between the main transformer and the bus section of the grid connection side of the large power grid or the grid connection side of the regional power grid. The grid-connected busbar circuit breaker includes a set of key circuit breakers between each busbar segment on the grid-connected side of the regional power grid within the core substation and between each grid-connected busbar segment and the main transformer. The grid-connected circuit breaker includes a set of key circuit breakers between the regional power grid grid connection line and the substation busbar.

2. The method for rapid identification of passive islanded grids in a regional power grid as described in claim 1, characterized in that: When a regional power grid is isolated, if the voltage or frequency of the grid-connected lines exceeds the isolated voltage or frequency setting and remains so for the duration of the isolated delay setting, the regional power grid is considered isolated; otherwise, it is considered non-isolated. When a regional power grid is not isolated, if the voltage or frequency of the grid-connected lines exceeds the isolated voltage or frequency setting, the regional power grid voltage or frequency is considered abnormal.

3. The method for rapid identification of passive islanded grids in a regional power grid as described in claim 2, characterized in that: The island voltage setting includes an upper limit value U for the island voltage. gh And the lower limit of the isolated grid voltage U gl When the grid connection line voltage is higher than U gh or below U gl When determining voltage islanding; The isolated network frequency setting includes an upper limit value f for the isolated network frequency. gh and the lower limit of the frequency of the isolated network f gl When the frequency of the grid connection line is higher than f gh or below f gl Time-based determination of frequency isolated networks; When an isolated grid is started, if it simultaneously meets either the voltage isolated grid or the frequency isolated grid condition and remains so for a time interval t, then the regional power grid is determined to be an isolated grid; otherwise, the regional power grid is determined to be a non-isolated grid. If the regional power grid is not isolated and meets the requirements of voltage isolation or frequency isolation, then the regional power grid is determined to be abnormal in voltage or frequency.

4. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 3.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 3.

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