Distributed power supply anti-islanding protection method, system, device and storage medium

Abstract

The application relates to the field of electronic power technology and discloses a distributed power source anti-island protection method, system, equipment and storage medium. The method comprises the following steps: obtaining the difference characteristics of the electrical quantity of a power distribution network according to a preset power distribution network network topology graph and a preset distributed power source nonlinear electrical model; obtaining a detection signal in the characteristic mode of the difference characteristics based on a preset active detection method, and generating a detection result according to the detection signal; performing weight correction and fusion on the detection result according to a preset information fusion method and a weight distribution method, so as to obtain an optimized topology structure of the power distribution network; performing station area side island judgment on the power distribution network based on 5G wireless communication, a preset tree search algorithm and the optimized topology structure, so as to obtain a judgment result; when the judgment result determines that the breaker position is abnormal or invalid, executing alarm and locking the protection of the power distribution network. The application realizes the detection of island operation and fast tripping within 100 milliseconds based on 5G wireless communication, and realizes anti-island protection.

Description

Technical Field

[0001] This invention relates to the field of electronic power technology, and in particular to a method, system, device, and storage medium for preventing islanding of distributed power sources. Background Technology

[0002] Economic and social development has led to a continuous increase in human demand for energy, making the development and widespread use of new energy sources a hot topic in power grid energy development. For example, clean energy sources such as distributed photovoltaic (PV) power on the distribution network side contribute to the construction of new power systems. In addition to being characterized by low pollution, high reliability and energy efficiency, and flexible installation locations, distributed power sources, such as PV, are well-suited to the dispersed nature of electricity demand and resource distribution, making them an important measure to resolve the contradictions between economic development, energy production and consumption, and environmental protection.

[0003] However, the high penetration rate of distributed photovoltaic (PV) power generation in the distribution network poses significant challenges to its safe operation, creating potential hazards and causing malfunctions in instantaneous and time-limited instantaneous overcurrent protection systems, thus affecting the network's operational reliability. Furthermore, the extensive use of power electronics technologies following the integration of PV and other distributed power sources may lead to equipment damage and delayed restoration of faulty lines, increasing power outage time for users and reducing the reliability of the distribution system. Therefore, in-depth research into the impact of distributed power sources on the distribution network and corresponding improvement strategies has become an urgent issue.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a method, system, device, and storage medium for preventing islanding of distributed power sources, aiming to solve the technical problems of reduced reliability of the distribution network operation caused by the connection of existing distributed power sources to the distribution network and the poor accuracy and speed of current islanding detection algorithms.

[0006] To achieve the above objectives, the present invention provides a distributed power supply anti-islanding protection method, the distributed power supply anti-islanding protection method comprising:

[0007] The differences in electrical quantities of the distribution network are obtained based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model.

[0008] Based on a preset active detection method, a detection signal is obtained from the feature pattern of the differential features, and a detection result is generated based on the detection signal;

[0009] Based on a preset information fusion method and weight allocation method, the detection results are weighted and fused to obtain an optimized topology of the power distribution network.

[0010] Based on 5G wireless communication, the distribution network is used to determine the islanding on the station side by using a preset tree search algorithm and the optimized topology to obtain the determination result.

[0011] When the judgment result determines that the circuit breaker position is abnormal or invalid, an alarm is triggered and the power distribution network is locked and protected.

[0012] In some embodiments, obtaining the difference characteristics of electrical quantities in the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model includes:

[0013] In the preset mode, the state equations of the converters of the distribution network under preset operating conditions are obtained based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model.

[0014] Based on the state equation and the preset time-domain waveform, the chaotic phenomenon, bifurcation characteristics and chaotic generation mechanism of the converter are determined to obtain the chaotic oscillation law of the converter.

[0015] Based on chaotic time series analysis and phase space reconstruction scheme, the difference characteristics of electrical quantities of the power distribution network during the chaotic oscillation process are determined according to the chaotic oscillation law.

[0016] In some embodiments, determining the chaotic phenomena, bifurcation characteristics, and chaos generation mechanism of the converter based on the state equation and a preset time-domain waveform to obtain the chaotic oscillation law of the converter includes:

[0017] Based on the state equation, bifurcation diagram, phase diagram, Poincaré cross section, inductor current, and time-domain waveform analysis of the output voltage, the chaotic phenomena, bifurcation characteristics, and chaos generation mechanism of the converter are obtained to obtain the variation law of the amplitude and frequency of the chaotic oscillation disturbance of the converter.

[0018] In some embodiments, the differential characteristics of electrical quantities in the distribution network include: microgrid voltage, frequency, power, and short-circuit capacity.

[0019] In some embodiments, the step of determining islanding on the distribution network based on 5G wireless communication using a preset tree search algorithm and the optimized topology to obtain a determination result includes:

[0020] The numbering of the tree search algorithm is optimized based on the correlation properties between the newly added branches and the non-zero injected elements of factorization, so as to obtain the initial tree search algorithm.

[0021] Based on the adjacency matrix to store the electrical primary wiring topology node information, the tree search path of the initial tree search algorithm is optimized according to the voltage level characteristics of the power system to obtain the preset tree search algorithm;

[0022] Based on 5G wireless communication, the distribution network is used to determine islanding on the station side through the preset tree search algorithm and the optimized topology structure to obtain the determination result.

[0023] In some embodiments, optimizing the numbering of the tree search algorithm based on the association properties between the newly added branch and the non-zero injected elements of the factorization to obtain an initial tree search algorithm includes:

[0024] Based on the highly sparse characteristics of the adjacency matrix of the optimized topology, the representation of the optimized topology is improved to obtain the improved adjacency matrix.

[0025] The numbering of the tree search algorithm is optimized based on the improved adjacency matrix, the association properties of newly added branches and non-zero injected elements in factorization, to obtain the initial tree search algorithm.

[0026] In some embodiments, when the determination result determines that the circuit breaker position is abnormal or invalid, executing an alarm and locking the protection of the distribution network includes:

[0027] When the judgment result determines that the circuit breaker position is abnormal or invalid, the system combines the circuit breaker position fault tolerance verification and anti-misoperation mechanism to determine whether to execute an alarm and lock out the protection of the distribution network.

[0028] Furthermore, to achieve the above objectives, the present invention also proposes a distributed power supply anti-islanding protection system, the distributed power supply anti-islanding protection system comprising:

[0029] The acquisition module is used to acquire the difference characteristics of electrical quantities of the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model;

[0030] The generation module is used to acquire detection signals based on the feature patterns of the differential features using a preset active detection method, and to generate detection results based on the detection signals.

[0031] The correction module is used to perform weight correction and fusion on the detection results according to a preset information fusion method and weight allocation method, so as to obtain the optimized topology of the power distribution network.

[0032] The judgment module is used to perform station-side islanding judgment on the distribution network based on 5G wireless communication, through a preset tree search algorithm and the optimized topology, so as to obtain the judgment result.

[0033] The execution module is used to execute an alarm and lock out the protection of the power distribution network when the judgment result determines that the circuit breaker position is abnormal or invalid.

[0034] Furthermore, to achieve the above objectives, the present invention also proposes a distributed power anti-islanding protection device, which includes: a memory, a processor, and a program stored in the memory and executable on the processor. When the program is executed by the processor, it implements the steps of the distributed power anti-islanding protection method as described in the above embodiments.

[0035] Furthermore, to achieve the above objectives, the present invention also proposes a storage medium storing a distributed power anti-islanding protection program, wherein when the distributed power anti-islanding protection program is executed by a processor, it implements the steps of the distributed power anti-islanding protection method as described in the above embodiments.

[0036] This invention obtains the differential characteristics of electrical quantities in the distribution network based on a preset distribution network topology diagram and a preset nonlinear electrical model of distributed power sources; acquires detection signals under the characteristic modes of the differential characteristics based on a preset active detection method, and generates detection results based on the detection signals; performs weight correction and fusion on the detection results according to a preset information fusion method and weight allocation method to obtain an optimized topology structure of the distribution network; and performs islanding judgment on the distribution network at the station level based on 5G wireless communication using a preset tree search algorithm and the optimized topology structure to obtain judgment results; when the judgment results determine that the circuit breaker position is abnormal or invalid, an alarm is executed and the distribution network is blocked for protection. This invention, based on the electrical characteristics of islanded operation and using 5G wireless communication for anti-islanding protection, can detect unplanned islanding operation within hundreds of milliseconds and quickly trip the circuit breaker by applying it to both switching stations and photovoltaic power stations. This overcomes the problems of slow action speed and poor sensitivity of existing anti-islanding protection, ensuring the safety of power grid equipment and maintenance personnel, thereby improving the operational stability of distributed power sources after they are connected to the distribution network. It solves the technical problems of reduced reliability of distribution network operation caused by the connection of distributed power sources and the poor accuracy and speed of current islanding detection algorithms. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the distributed power supply anti-islanding protection device for the hardware operating environment involved in the embodiments of the present invention;

[0038] Figure 2 This is a flowchart illustrating the first embodiment of the distributed power supply anti-islanding protection method of the present invention;

[0039] Figure 3 This is a flowchart illustrating the second embodiment of the distributed power supply anti-islanding protection method of the present invention;

[0040] Figure 4 This is a structural block diagram of the first embodiment of the distributed power supply anti-islanding protection system of the present invention.

[0041] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0044] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0045] The widespread integration of clean energy sources such as distributed photovoltaic (PV) power into the distribution network is undoubtedly a crucial step in achieving the "dual carbon" target and an important way to help build a new power system from the distribution network side. In addition to its advantages of low pollution, high reliability and energy efficiency, and flexible installation locations, distributed power sources, such as PV, are well-suited to the dispersed nature of electricity demand and resource distribution. This makes them an important measure to resolve the contradictions between economic development, energy production and consumption, and environmental protection.

[0046] However, the high penetration rate of distributed photovoltaic (PV) systems in the distribution network poses significant challenges to the safe operation of the network, primarily in the following aspects: First, PV output power is highly dependent on weather changes. Natural variations such as solar radiation cause fluctuations in PV system power, and user loads also change in real time, with these changes not synchronized with the PV power generation patterns. With high PV penetration, the power generated by PV exceeds the load demand, leading to reverse power flow along feeders and causing feeder voltage rises, sometimes exceeding upper limits, posing a threat to the safe and stable operation of the system. The continuous integration of distributed energy sources like PV impacts the configuration and settings of distribution network automation systems and protection systems. When the PV power output is less than its rated power, the short-circuit current level in the distribution network may be higher than when the PV power output is at its rated power. According to existing setting schemes for the distribution network's instantaneous and time-limited instantaneous overcurrent protection, malfunctions may occur when the PV power output is less than its rated power. Considering the fluctuating nature of PV power output, which is often less than its rated power... Therefore, setting the distribution network current protection based on the short-circuit current level of the distribution network when the photovoltaic power source outputs its rated power will affect the safety and reliability of the distribution network operation.

[0047] It is evident that the high-density, large-scale integration of distributed generation into the distribution network alters the distribution of short-circuit currents, significantly impacting the correct operation of protection systems. Furthermore, distributed generation typically connects to medium- or low-voltage distribution systems, which are mostly single-source radial structures employing instantaneous or time-limited instantaneous protection methods, lacking directionality. While this protection method effectively protects all lines in existing radial distribution networks, the injected power reduces the relay protection range after the integration of distributed generation, failing to reliably protect the entire line and even causing malfunctions in relay protection systems connected to distributed generation systems during faults in other parallel branches. More importantly, the extensive use of power electronics technology following the integration of distributed generation, such as photovoltaic power, fundamentally alters the fault characteristics of the distribution system, leading to unclear fault current characteristics and fault calculation models. If a fault occurs on a line containing a renewable energy source and its protection trips, and the source fails to disconnect to avoid reclosing, asynchronous reclosing of the faulty line may occur, causing equipment damage, delays in restoring the faulty line, increased power outage time for users, and reduced reliability of the distribution system. To ensure the stable and efficient operation of distributed power sources, it is of great significance to study new distribution network protection schemes and parameter setting specifications applicable to distributed power sources after their integration.

[0048] Secondly, in distribution networks with high-penetration photovoltaic (PV) power, after a system failure, distributed generation sources and nearby loads may form power islands. In this case, the islanded network will find it difficult to maintain synchronization with the main grid, and the phase angle difference between them will occur anywhere between 0 and 360°. If reclosing is attempted at this time, the conditions for synchronous reclosing are difficult to meet, and asynchronous reclosing will bring large inrush currents and transient overvoltages, causing significant damage to the generating units and grid equipment. When the islanding detection and disconnection time of a PV power station is long, it causes abnormalities in the timing coordination of automatic transfer switch (ATS) operations, resulting in excessively long ATS times or even failures. Therefore, when a distribution network connected to distributed generation experiences a failure, it can easily lead to local grid islanding, affecting the reliable operation of regional grid reclosing and ATS. More seriously, in islanded operation, abnormal energization of equipment may even endanger the lives of maintenance personnel.

[0049] Active detection methods have been widely studied and applied due to their high accuracy and small blind zone. However, due to the diverse operating conditions of microgrids and the varying types of distributed power sources, grid structures, and load compositions, a single method is currently insufficient to guarantee the accuracy and speed of active detection for all isolated microgrids. Currently, islanding detection methods mainly include communication-based methods, passive detection methods, and active detection methods. The former is highly dependent on communication channels; passive detection methods are simple to implement and have little impact on power quality, but they have blind zones; active detection methods mostly establish positive feedback loops based on the positive feedback relationship between reactive current and frequency, causing the microgrid converter frequency to rapidly change in one direction after voltage loss to achieve islanding detection, promising good reliability, but currently, most methods use a single criterion. In fact, microgrids have complex structures and significant operational variations; islanding detection methods based on a single criterion often cannot fully cover various operating conditions. Therefore, it is necessary to research comprehensive judgment methods based on multiple information sources to minimize the coverage blind zones of each method. Therefore, conducting research on anti-islanding detection in active distribution networks is particularly important for ensuring the reliability of distribution networks including distributed power sources such as photovoltaics and for protecting the safety of operation and maintenance workers.

[0050] The above analysis shows that it is urgent to conduct in-depth research on the impact of distributed generation on distribution network relay protection and to develop improvement strategies. In particular, in traditional power grid fault analysis, the power supply model is mainly an AC synchronous motor. However, during power grid faults, the transient components and attenuation characteristics of the fault current fed into the grid by distributed generation change significantly compared to traditional AC synchronous motors. This makes it difficult for traditional short-circuit current analysis theories and methods based on AC synchronous motor power supplies to meet the requirements of power grid fault analysis after distributed generation integration.

[0051] The large-scale integration of distributed photovoltaic (PV) power generation systems has brought new problems. For example, when PV power generation stops due to faults, the grid-connected PV systems installed at various user terminals may fail to detect the power outage in time and disconnect themselves from the grid. This creates an island effect, supplying power to surrounding loads, while the power company cannot monitor its power supply status. The island effect can adversely affect equipment operation, including: endangering the safety of power company line maintenance personnel; affecting the operation of protection switches in the distribution network; easily causing voltage and frequency instability for users in the islanded area; causing phase asynchrony problems when the power company restores power; and causing phase loss problems due to single-phase power supply. The more PV grid-connected systems are connected to the AC grid, the higher the probability of the island effect. Therefore, a suitable strategy is needed to prevent the increasingly serious island effect problem. Currently, the accuracy and speed of island detection algorithms are insufficient, easily leading to unplanned islanding. Researching optimized distribution network protection and control strategies adapted to high-penetration PV integration is a major technical requirement for building a new type of power system and a national requirement for promoting the achievement of "dual-carbon" goals.

[0052] In view of the above problems, the present invention proposes a method, system, device and storage medium for distributed power supply anti-islanding protection.

[0053] Reference Figure 1 , Figure 1 This is a schematic diagram of the distributed power supply anti-islanding protection device structure for the hardware operating environment involved in the embodiments of the present invention.

[0054] like Figure 1 As shown, the distributed power supply anti-islanding protection device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen, and optionally, it may also include a standard wired interface or a wireless interface. In this invention, the wired interface of the user interface 1003 may be a USB interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be a high-speed random access memory (RAM) or a non-volatile memory (NVM), such as a disk storage device. The memory 1005 may also optionally be a storage device independent of the aforementioned processor 1001.

[0055] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on distributed power supply anti-islanding protection devices, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0056] like Figure 1 As shown, the memory 1005, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a distributed power supply anti-islanding protection program.

[0057] exist Figure 1 In the distributed power anti-islanding protection device shown, the network interface 1004 is mainly used to connect to the backend server and communicate data with the backend server; the user interface 1003 is mainly used to connect to user equipment; the distributed power anti-islanding protection device calls the distributed power anti-islanding protection program stored in the memory 1005 through the processor 1001 and executes the distributed power anti-islanding protection method provided in the embodiment of the present invention.

[0058] Based on the above hardware structure, an embodiment of the distributed power supply anti-islanding protection method of the present invention is proposed.

[0059] Reference Figure 2 , Figure 2 This is a flowchart illustrating a first embodiment of the distributed power supply anti-islanding protection method of the present invention. The first embodiment includes the following steps:

[0060] Step S10: Obtain the difference characteristics of electrical quantities of the distribution network based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model.

[0061] Step S20: Based on a preset active detection method, acquire a detection signal under the feature pattern of the difference feature, and generate a detection result based on the detection signal.

[0062] Step S30: According to the preset information fusion method and weight allocation method, the detection results are weighted and fused to obtain the optimized topology of the power distribution network.

[0063] Step S40: Based on 5G wireless communication, the distribution network is used to determine the islanding on the station side through a preset tree search algorithm and the optimized topology to obtain the determination result.

[0064] Step S50: When the judgment result determines that the circuit breaker position is abnormal or invalid, an alarm is triggered and the power distribution network is locked.

[0065] It should be noted that the executing entity in this embodiment is the distributed power source anti-islanding protection device, which can be an electronic device such as a personal computer or server; this embodiment does not limit this. Distributed power sources include, but are not limited to, photovoltaic (PV), wind turbines, and energy storage. This embodiment uses PV as the distributed power source and a distribution network containing distributed power sources (including PV) as an example for explanation.

[0066] For example, the process of obtaining the difference characteristics of electrical quantities of the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model may include: in a preset mode, obtaining the state equation of the converter of the distribution network under preset operating conditions based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model; determining the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and preset time-domain waveforms to obtain the chaotic oscillation law of the converter; and determining the difference characteristics of electrical quantities of the distribution network during the chaotic oscillation process of the converter based on the chaotic time series analysis and phase space reconstruction scheme. The process of determining the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and preset time-domain waveforms to obtain the chaotic oscillation law of the converter may include: analyzing the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and the time-domain waveforms of the bifurcation diagram, phase diagram, Poincaré cross section, inductor current, and output voltage to obtain the variation law of the amplitude and frequency of the chaotic oscillation disturbance of the converter.

[0067] Specifically, considering the current status, existing problems, development trends, and business needs of distribution sensing systems containing distributed power sources, it is necessary to re-examine the sensing information from the perspective of core assets. Starting from the perspective of unique source data and global information sharing, and fully leveraging industrial digital twin technology that integrates data and models, the architecture of the distribution sensing system should be optimized. Lightweight and abundant distributed edge computing power should be used to reconstruct the decision-making capabilities of distribution data, and the distribution digital-analog mapping capabilities should be expanded and deepened to drive key capabilities in distribution sensing control, data integration, and predictive analysis. This will solve the long-standing challenges of real-time business requirements, flexibility, and diversity. The design of a hierarchical and domain-based information architecture for the distribution sensing system should be studied, and the evolution path of the target architecture should be realized from the perspectives of main station construction, terminal development, communication selection, and model improvement. For distribution network topologies containing various types of distributed power sources, a breadth-first search method should be used to detect complex distribution network subgraphs. Then, based on radial topology conditions, the subgraph structure should be determined, thereby achieving topology optimization and expansion to obtain an optimized and expanded distribution network topology.

[0068] Furthermore, combining the optimized and expanded distribution network topology (preset distribution network topology) and the electrical model of the nonlinear power electronic components of the distributed energy grid-connected converter (preset distributed power source nonlinear electrical model), the state equations of the converter under different operating conditions in voltage or current modes are derived and analyzed. The chaotic phenomena, bifurcation characteristics, and chaos generation mechanisms in the converter are analyzed from the perspectives of bifurcation diagrams, phase diagrams, Poincaré cross sections, inductor current, and output voltage time-domain waveforms, respectively, yielding the variation laws of the amplitude and frequency of chaotic oscillation disturbances. Based on chaotic time series analysis and phase space reconstruction technology, the differences in electrical quantities during chaotic oscillation are obtained, including but not limited to microgrid voltage, frequency, power, and short-circuit capacity.

[0069] For example, the process of determining islanding on the distribution network at the station level based on 5G wireless communication using a preset tree search algorithm and the optimized topology to obtain a determination result may include: optimizing the number of the tree search algorithm based on the correlation properties of newly added branches and non-zero injected elements in factorization to obtain an initial tree search algorithm; optimizing the tree search path of the initial tree search algorithm based on the voltage level characteristics of the power system by storing electrical primary wiring topology node information in the adjacency matrix to obtain a preset tree search algorithm; and determining islanding on the distribution network at the station level based on 5G wireless communication using the preset tree search algorithm and the optimized topology to obtain a determination result.

[0070] Specifically, based on active detection methods (such as frequency offset detection, sliding mode frequency drift detection, periodic current interference detection, and frequency change detection), detection signals with similar or different characteristic patterns (such as frequency offset index, frequency shift limit signal, and voltage fluctuation signal) are acquired. Based on the historical records of the correctness of the detection scheme, information fusion methods such as DS are used to perform data fusion and weight correction on multiple criteria information.

[0071] Based on the tree search algorithm, a voltage-level-based topology analysis method is used to identify isolated nodes on the site side using 5G wireless communication. Addressing the highly sparse nature of the adjacency matrix in the stored network topology, its representation is improved, and the improved adjacency matrix is ​​applied to node optimization numbering, pre-determination of retrieval information, and the formation of the node admittance matrix. During factorization, to achieve non-zero retrieval in the column direction, column-oriented storage information is added, and corresponding retrieval methods are defined. Based on the correlation between newly added branches and non-zero injected elements in factorization during the optimization numbering process, the positions of newly added elements are recorded and a storage framework is formed while optimizing the numbering. Then, electrical primary wiring topology node information is stored based on the adjacency matrix. The tree search path is optimized using the voltage level characteristics of the power system, effectively avoiding the high computational cost of traditional full matrix multiplication algorithms and the low search efficiency of tree search algorithms.

[0072] For example, when the judgment result determines that the circuit breaker position is abnormal or invalid, the process of executing an alarm and locking the protection of the distribution network may include: when the judgment result determines that the circuit breaker position is abnormal or invalid, determining whether to execute an alarm and lock the protection of the distribution network in conjunction with the circuit breaker position fault tolerance verification and anti-misoperation mechanism.

[0073] Specifically, when the circuit breaker position is abnormal or invalid, the system uses an alarm and lockout protection mechanism, combined with a circuit breaker position fault tolerance verification mechanism, to prevent the false issuance of islanding trip commands, thereby ensuring the reliability of the distributed power supply anti-islanding protection method.

[0074] It should be noted that the distribution network includes systems with a non-effectively grounded neutral point. A hybrid distribution network may also include a 24kV neutral-grounded network.

[0075] In this embodiment, considering large-scale photovoltaic grid connection, and based on actual field conditions, islanding operation analysis under various operating conditions is conducted. The electrical characteristics of islanding operation are studied, and a 5G communication-based anti-islanding protection device is developed. By applying it to both the switching station and the photovoltaic power station, it achieves rapid tripping within milliseconds to detect unplanned islanding conditions, overcoming the problems of slow action speed and poor sensitivity of existing anti-islanding protection. This ensures the safety of grid equipment and maintenance personnel, meeting the future power grid development trend of high-penetration photovoltaic power access and increasingly prominent power electronics characteristics. Focusing on grid relay protection and control, the adaptability of existing protection in distribution networks with distributed power sources such as photovoltaics is studied. A new principle for rapid line protection that fully exploits the transient characteristics of faults in the time-frequency domain is developed, comprehensively constructing a security defense system for complex power systems with distributed power access in the future, promoting the access of distributed renewable energy sources to the distribution network. Establishing and improving the basic theories and key technologies for effectively avoiding the risks of photovoltaic access to the distribution network, and continuously improving the level of relay protection technology, will help solve the development problems of distributed power access to the grid and contribute to the realization of the "dual carbon" goal.

[0076] In this embodiment, the differential characteristics of electrical quantities in the distribution network are obtained based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model. A preset active detection method is used to acquire detection signals under the characteristic modes of these differential characteristics, and detection results are generated based on these signals. The detection results are then weighted and fused according to a preset information fusion method and weight allocation method to obtain an optimized distribution network topology. Based on 5G wireless communication, a preset tree search algorithm and optimized topology are used to determine islanding on the distribution network's substation side to obtain a judgment result. When the judgment result determines that the circuit breaker position is abnormal or invalid, an alarm is triggered and the distribution network is locked for protection. This embodiment uses 5G wireless communication to perform anti-islanding protection based on the electrical characteristics of islanded operation. By applying this method to both switching stations and photovoltaic power plants, it can detect unplanned islanding operation within milliseconds and quickly trip the circuit breaker, overcoming the problems of slow action speed and poor sensitivity of existing anti-islanding protection methods. This ensures the safety of power grid equipment and maintenance personnel, thereby improving the operational stability of distributed power sources after they are connected to the distribution network. It also solves the technical problems of reduced reliability of the distribution network after distributed power sources are connected and the current islanding detection algorithm's accuracy and speed are inadequate.

[0077] Reference Figure 3 , Figure 3 This is a flowchart illustrating the second embodiment of the distributed power supply anti-islanding protection method of the present invention, based on the above. Figure 2 The first embodiment shown presents a second embodiment of the distributed power supply anti-islanding protection method of the present invention.

[0078] In the second embodiment, step S40 includes:

[0079] Step S401: Optimize the numbering of the tree search algorithm based on the correlation properties between the newly added branch and the non-zero injected elements of factorization to obtain the initial tree search algorithm.

[0080] Step S402: Based on the adjacency matrix, store the electrical primary wiring topology node information, and optimize the tree search path of the initial tree search algorithm according to the voltage level characteristics of the power system to obtain the preset tree search algorithm.

[0081] Step S403: Based on 5G wireless communication, the distribution network is used to determine the islanding status on the station side through the preset tree search algorithm and the optimized topology structure to obtain the determination result.

[0082] For example, the process of optimizing the tree search algorithm number based on the association properties of the newly added branches and the non-zero injected elements of factorization to obtain the initial tree search algorithm may include: improving the representation of the optimized topology based on the highly sparse characteristics of the adjacency matrix of the optimized topology to obtain an improved adjacency matrix; and optimizing the tree search algorithm number based on the improved adjacency matrix, the association properties of the newly added branches and the non-zero injected elements of factorization to obtain the initial tree search algorithm.

[0083] Specifically, based on active detection methods (such as frequency offset detection, sliding mode frequency drift detection, periodic current interference detection, and frequency change detection), detection signals with similar or different characteristic patterns (such as frequency offset index, frequency shift limit signal, and voltage fluctuation signal) are acquired. Based on the historical records of the correctness of the detection scheme, information fusion methods such as DS are used to perform data fusion and weight correction on multiple criteria information.

[0084] Based on the tree search algorithm, a voltage-level-based topology analysis method is used to identify isolated nodes on the site side using 5G wireless communication. Addressing the highly sparse nature of the adjacency matrix in the stored network topology, its representation is improved, and the improved adjacency matrix is ​​applied to node optimization numbering, pre-determination of retrieval information, and the formation of the node admittance matrix. During factorization, to achieve non-zero retrieval in the column direction, column-oriented storage information is added, and corresponding retrieval methods are defined. Based on the correlation between newly added branches and non-zero injected elements in factorization during the optimization numbering process, the positions of newly added elements are recorded and a storage framework is formed while optimizing the numbering. Then, electrical primary wiring topology node information is stored based on the adjacency matrix. The tree search path is optimized using the voltage level characteristics of the power system, effectively avoiding the high computational cost of traditional full matrix multiplication algorithms and the low search efficiency of tree search algorithms.

[0085] It is understandable that the topology identification method for distributed photovoltaic active power distribution networks based on 5G communication (distributed power source anti-islanding protection method) specifically addresses the three main application scenarios defined by the International Telecommunication Union (ITU) for 5G: enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (uRLLC). The eMBB scenario focuses on human-centric consumer services such as communication, entertainment, and social interaction, providing user experience speeds of 1 to 5 Gbit / s and latency of 10 to 50 ms, with some applications requiring large-scale connectivity. The mMTC scenario primarily targets IoT sensing and data collection, supporting massive data, small packet data, and global data transmission, meeting the requirement of 1 million connections / km. 2 Indicators include data rates of 1 to 100 Mbit / s and latency in the 50 ms range.

[0086] Tree-based topology identification methods form the foundation for anti-islanding protection technologies based on 5G communication signals, applicable to various system structures. The tree-based search method transforms the power grid topology into a graph and uses data structures such as adjacency matrices or adjacency lists to store node connection information. It then employs either depth-first search (DFS) or breadth-first search (BFS) algorithms to search the topology graph and determine the connectivity between distributed generation (DG) nodes and system power sources. The tree-based search method searches for the connectivity between distributed generation sources and system power sources in real time, thereby obtaining the islanding status of the distributed generation source.

[0087] Distributed generation, such as photovoltaic (PV) power, is typically connected to medium- or low-voltage distribution systems. The extensive connection of distributed power sources to low-voltage distribution networks will have a wide-ranging and profound impact. For example, PV power is mostly connected to regional grids with weak connections to the main grid. When the regional grid disconnects from the main grid, PV power can easily become isolated from the loads within the regional grid, making it difficult for PV anti-islanding detection devices to accurately and promptly obtain islanding information. In grid fault scenarios, passive islanding detection schemes for the aforementioned distributed PV power sources generally have a large non-detection zone (NDZ) and often require a long time to complete islanding detection and disconnect the PV power source. This will seriously affect the reliable operation of regional grid reclosing or automatic transfer switching and the safety of maintenance workers. Regarding islanding detection technology in distribution networks with high-penetration distributed power sources, active islanding detection schemes such as active frequency shifting methods, including Active Frequency Drift (AFD), Sandia Frequency Shift (SFS), and Slide-Mode Frequency Shift (SMS), can be used. Among them, the AFD method and SFS method adopt a strategy based on frequency offset perturbation, while the SMS method adopts a strategy based on phase offset perturbation. Through in-depth analysis of the advantages and disadvantages of various remote, passive, and active microgrid islanding detection technologies, this paper explores islanding detection methods for multiple distributed power sources. Based on the above, a multi-data integrated judgment islanding detection method adapted to different control strategies for single inverters and multi-machine clusters is proposed, which will be more adaptable to actual operating conditions.

[0088] This embodiment, based on the advantages, disadvantages, and applicability of traditional passive, active, and remote islanding protection algorithms, addresses the common problems of cumbersome judgment, low efficiency, and blind spots in traditional islanding protection detection technologies. It proposes a 5G-based active distribution network topology identification method (distributed power source anti-islanding protection method) for distributed photovoltaic (PV) active distribution networks, adapting to the multi-data comprehensive judgment islanding detection for single inverters and multi-machine clusters under different control strategies. Utilizing the limited grid information rapidly acquired through 5G wireless communication, the embodiment studies the islanding operation status judgment technology for active distribution networks based on topologies of different voltage levels, and further proposes a practical new anti-islanding protection scheme. According to regulations, when PV experiences islanding, the connection to the grid must be disconnected within 2 seconds; therefore, configuring fast and reliable anti-islanding protection is essential for the safe operation of the grid. Based on this, in-depth research into fault identification methods and anti-islanding protection technologies will further improve the safe operation level of distribution networks with high PV penetration. Using the distributed power source anti-islanding protection method in this embodiment, the islanding protection action time can be improved from the internationally required less than 2 seconds to less than 200 milliseconds.

[0089] For example, active islanding detection methods for islanded microgrids typically involve controlling the inverter to generate disturbances in its output power, frequency, or phase, thereby triggering the islanding detection circuit. This method offers higher detection accuracy and a smaller non-detection zone. Currently, mainstream active islanding detection technologies for microgrids include frequency offset detection, sliding mode frequency drift detection, periodic current interference detection, and frequency mutation detection. However, during normal operation, microgrids exhibit diverse operating modes, with varying distributed power sources, grid structures, and load compositions, resulting in a large volume of data. Due to the bandwidth and transmission speed limitations of traditional communication methods, it is difficult to guarantee the accuracy and speed of active detection for all islanded microgrids. However, comprehensively collecting real-time operational data from the microgrid can effectively address these issues. Therefore, 5G communication technology is used to collect real-time panoramic data from various new energy power stations in the microgrid, and a multi-data comprehensive judgment method is designed to identify and use the correct data. Furthermore, based on the results of active detection technologies of different principles, appropriate criterion fusion and weight allocation methods are adopted to correct and fuse the results generated by each active detection technology to improve the accuracy of active and rapid detection in isolated microgrids.

[0090] In this embodiment, the numbering of the tree search algorithm is optimized based on the correlation properties between the newly added branch and the non-zero injected elements of factorization to obtain an initial tree search algorithm. Based on the adjacency matrix storing the electrical primary wiring topology node information, the tree search path of the initial tree search algorithm is optimized according to the voltage level characteristics of the power system to obtain a preset tree search algorithm. Based on 5G wireless communication, the preset tree search algorithm and the optimized topology structure are used to determine islanding on the distribution network side to obtain the determination result. This embodiment uses 5G wireless communication to perform anti-islanding protection based on the electrical characteristics of islanded operation. By applying it to both the switching station and the photovoltaic power station, it can detect unplanned islanding operation within hundreds of milliseconds and quickly trip the circuit breaker, overcoming the problems of slow action speed and poor sensitivity of existing anti-islanding protection methods. This ensures the safety of power grid equipment and maintenance personnel, thereby improving the operational stability of distributed power sources after they are connected to the distribution network. It solves the technical problems of reduced reliability of the distribution network operation caused by the connection of distributed power sources and the poor accuracy and speed of current islanding detection algorithms.

[0091] Furthermore, this embodiment of the invention also proposes a storage medium storing a distributed power supply anti-islanding protection program, which, when executed by a processor, implements the steps of the distributed power supply anti-islanding protection method described above.

[0092] Since this storage medium adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0093] In addition, refer to Figure 4 This invention also proposes a distributed power supply anti-islanding protection system, which includes:

[0094] The acquisition module 10 is used to acquire the difference characteristics of electrical quantities of the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model;

[0095] The generation module 20 is used to acquire a detection signal based on the feature pattern of the difference feature using a preset active detection method, and generate a detection result based on the detection signal;

[0096] The correction module 30 is used to perform weight correction and fusion on the detection results according to a preset information fusion method and weight allocation method, so as to obtain the optimized topology of the power distribution network.

[0097] The judgment module 40 is used to determine the islanding of the distribution network on the station side based on 5G wireless communication, through a preset tree search algorithm and the optimized topology, so as to obtain the judgment result.

[0098] The execution module 50 is used to execute an alarm and lock out the protection of the power distribution network when the judgment result determines that the circuit breaker position is abnormal or invalid.

[0099] It should be noted that distributed power sources include, but are not limited to, photovoltaic (PV) power, wind turbines, and energy storage. This embodiment uses PV power as the distributed power source and a distribution network that includes distributed power sources (including PV power) as an example for illustration.

[0100] For example, the process of obtaining the difference characteristics of electrical quantities of the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model may include: in a preset mode, obtaining the state equation of the converter of the distribution network under preset operating conditions based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model; determining the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and preset time-domain waveforms to obtain the chaotic oscillation law of the converter; and determining the difference characteristics of electrical quantities of the distribution network during the chaotic oscillation process of the converter based on the chaotic time series analysis and phase space reconstruction scheme. The process of determining the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and preset time-domain waveforms to obtain the chaotic oscillation law of the converter may include: analyzing the chaotic phenomenon, bifurcation characteristics, and chaotic generation mechanism of the converter based on the state equation and the time-domain waveforms of the bifurcation diagram, phase diagram, Poincaré cross section, inductor current, and output voltage to obtain the variation law of the amplitude and frequency of the chaotic oscillation disturbance of the converter.

[0101] Specifically, considering the current status, existing problems, development trends, and business needs of distribution sensing systems containing distributed power sources, it is necessary to re-examine the sensing information from the perspective of core assets. Starting from the perspective of unique source data and global information sharing, and fully leveraging industrial digital twin technology that integrates data and models, the architecture of the distribution sensing system should be optimized. Lightweight and abundant distributed edge computing power should be used to reconstruct the decision-making capabilities of distribution data, and the distribution digital-analog mapping capabilities should be expanded and deepened to drive key capabilities in distribution sensing control, data integration, and predictive analysis. This will solve the long-standing challenges of real-time business requirements, flexibility, and diversity. The design of a hierarchical and domain-based information architecture for the distribution sensing system should be studied, and the evolution path of the target architecture should be realized from the perspectives of main station construction, terminal development, communication selection, and model improvement. For distribution network topologies containing various types of distributed power sources, a breadth-first search method should be used to detect complex distribution network subgraphs. Then, based on radial topology conditions, the subgraph structure should be determined, thereby achieving topology optimization and expansion to obtain an optimized and expanded distribution network topology.

[0102] Furthermore, combining the optimized and expanded distribution network topology (preset distribution network topology) and the electrical model of the nonlinear power electronic components of the distributed energy grid-connected converter (preset distributed power source nonlinear electrical model), the state equations of the converter under different operating conditions in voltage or current modes are derived and analyzed. The chaotic phenomena, bifurcation characteristics, and chaos generation mechanisms in the converter are analyzed from the perspectives of bifurcation diagrams, phase diagrams, Poincaré cross sections, inductor current, and output voltage time-domain waveforms, respectively, yielding the variation laws of the amplitude and frequency of chaotic oscillation disturbances. Based on chaotic time series analysis and phase space reconstruction technology, the differences in electrical quantities during chaotic oscillation are obtained, including but not limited to microgrid voltage, frequency, power, and short-circuit capacity.

[0103] For example, the process of determining islanding on the distribution network at the station level based on 5G wireless communication using a preset tree search algorithm and the optimized topology to obtain a determination result may include: optimizing the number of the tree search algorithm based on the correlation properties of newly added branches and non-zero injected elements in factorization to obtain an initial tree search algorithm; optimizing the tree search path of the initial tree search algorithm based on the voltage level characteristics of the power system by storing electrical primary wiring topology node information in the adjacency matrix to obtain a preset tree search algorithm; and determining islanding on the distribution network at the station level based on 5G wireless communication using the preset tree search algorithm and the optimized topology to obtain a determination result.

[0104] Specifically, based on active detection methods (such as frequency offset detection, sliding mode frequency drift detection, periodic current interference detection, and frequency change detection), detection signals with similar or different characteristic patterns (such as frequency offset index, frequency shift limit signal, and voltage fluctuation signal) are acquired. Based on the historical records of the correctness of the detection scheme, information fusion methods such as DS are used to perform data fusion and weight correction on multiple criteria information.

[0105] Based on the tree search algorithm, a voltage-level-based topology analysis method is used to identify isolated nodes on the site side using 5G wireless communication. Addressing the highly sparse nature of the adjacency matrix in the stored network topology, its representation is improved, and the improved adjacency matrix is ​​applied to node optimization numbering, pre-determination of retrieval information, and the formation of the node admittance matrix. During factorization, to achieve non-zero retrieval in the column direction, column-oriented storage information is added, and corresponding retrieval methods are defined. Based on the correlation between newly added branches and non-zero injected elements in factorization during the optimization numbering process, the positions of newly added elements are recorded and a storage framework is formed while optimizing the numbering. Then, electrical primary wiring topology node information is stored based on the adjacency matrix. The tree search path is optimized using the voltage level characteristics of the power system, effectively avoiding the high computational cost of traditional full matrix multiplication algorithms and the low search efficiency of tree search algorithms.

[0106] For example, when the judgment result determines that the circuit breaker position is abnormal or invalid, the process of executing an alarm and locking the protection of the distribution network may include: when the judgment result determines that the circuit breaker position is abnormal or invalid, determining whether to execute an alarm and lock the protection of the distribution network in conjunction with the circuit breaker position fault tolerance verification and anti-misoperation mechanism.

[0107] Specifically, when the circuit breaker position is abnormal or invalid, the system uses an alarm and lockout protection mechanism, combined with a circuit breaker position fault tolerance verification mechanism, to prevent the false issuance of islanding trip commands, thereby ensuring the reliability of the distributed power supply anti-islanding protection method.

[0108] It should be noted that the distribution network includes systems with a non-effectively grounded neutral point. A hybrid distribution network may also include a 24kV neutral-grounded network.

[0109] In this embodiment, considering large-scale photovoltaic grid connection, and based on actual field conditions, islanding operation analysis under various operating conditions is conducted. The electrical characteristics of islanding operation are studied, and a 5G communication-based anti-islanding protection device is developed. By applying it to both the switching station and the photovoltaic power station, it achieves rapid tripping within milliseconds to detect unplanned islanding conditions, overcoming the problems of slow action speed and poor sensitivity of existing anti-islanding protection. This ensures the safety of grid equipment and maintenance personnel, meeting the future power grid development trend of high-penetration photovoltaic power access and increasingly prominent power electronics characteristics. Focusing on grid relay protection and control, the adaptability of existing protection in distribution networks with distributed power sources such as photovoltaics is studied. A new principle for rapid line protection that fully exploits the transient characteristics of faults in the time-frequency domain is developed, comprehensively constructing a security defense system for complex power systems with distributed power access in the future, promoting the access of distributed renewable energy sources to the distribution network. Establishing and improving the basic theories and key technologies for effectively avoiding the risks of photovoltaic access to the distribution network, and continuously improving the level of relay protection technology, will help solve the development problems of distributed power access to the grid and contribute to the realization of the "dual carbon" goal.

[0110] This embodiment proposes a distributed power supply anti-islanding protection system, which includes: an acquisition module 10, used to acquire the difference characteristics of electrical quantities of the distribution network according to a preset distribution network topology diagram and a preset distributed power supply nonlinear electrical model; a generation module 20, used to acquire detection signals based on the feature mode of the difference characteristics according to a preset active detection method, and generate detection results according to the detection signals; a correction module 30, used to perform weight correction and fusion on the detection results according to a preset information fusion method and a weight allocation method to obtain an optimized topology of the distribution network; a judgment module 40, used to perform station-side islanding judgment on the distribution network based on 5G wireless communication, through a preset tree search algorithm and the optimized topology, to obtain a judgment result; and an execution module 50, used to execute an alarm and lock out the protection of the distribution network when the judgment result determines that the circuit breaker position is abnormal or invalid. This embodiment utilizes 5G wireless communication to implement anti-islanding protection based on the electrical characteristics of islanded operation. By applying it to both the switching station and the photovoltaic power station, it can detect unplanned islanded operation within milliseconds and quickly trip the circuit breaker. This overcomes the problems of slow action speed and poor sensitivity of existing anti-islanding protection, ensuring the safety of power grid equipment and maintenance personnel. It also improves the operational stability of distributed power sources after they are connected to the distribution network, and solves the technical problems of reduced reliability of the distribution network after distributed power sources are connected to the distribution network and the poor accuracy and speed of current islanding detection algorithms.

[0111] Other embodiments or specific implementations of the distributed power supply anti-islanding protection system of the present invention can be referred to the above-described method embodiments, and will not be repeated here.

[0112] It should be understood that the above are merely illustrative examples and do not constitute any limitation on the technical solutions of the present invention. In specific applications, those skilled in the art can make settings as needed, and the present invention does not impose any restrictions on this.

[0113] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of the workflow to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here.

[0114] In addition, for technical details not described in detail in this embodiment, please refer to the image reconstruction method applied to the electrical impedance imaging system as described above provided in any embodiment of the present invention, which will not be repeated here.

[0115] Furthermore, it should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0116] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0117] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as read-only memory (ROM) / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0118] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preventing islanding in distributed power sources, characterized in that, The distributed power supply anti-islanding protection method includes: The differences in electrical quantities of the distribution network are obtained based on the preset distribution network topology diagram and the preset distributed power source nonlinear electrical model. Based on a preset active detection method, a detection signal is obtained from the feature pattern of the differential features, and a detection result is generated based on the detection signal; Based on a preset information fusion method and weight allocation method, the detection results are weighted and fused to obtain an optimized topology of the power distribution network. Based on 5G wireless communication, the distribution network is used to determine the islanding on the station side by using a preset tree search algorithm and the optimized topology to obtain the determination result. When the judgment result determines that the circuit breaker position is abnormal or invalid, an alarm is triggered and the power distribution network is locked and protected. The method involves obtaining the differences in electrical quantities of the distribution network based on a preset distribution network topology and a preset distributed power source nonlinear electrical model. This includes: obtaining the state equations of the converter under preset operating conditions based on the preset distribution network topology and the preset distributed power source nonlinear electrical model in a preset mode; determining the chaotic phenomena, bifurcation characteristics, and chaotic generation mechanisms of the converter based on the state equations and preset time-domain waveforms to obtain the chaotic oscillation law of the converter; and determining the differences in electrical quantities of the distribution network during chaotic oscillation based on the chaotic oscillation law of the converter using chaotic time series analysis and phase space reconstruction schemes. Specifically, determining the chaotic phenomena, bifurcation characteristics, and chaotic generation mechanisms of the converter based on the state equations and preset time-domain waveforms to obtain the chaotic oscillation law of the converter includes: analyzing the chaotic phenomena, bifurcation characteristics, and chaotic generation mechanisms of the converter based on the state equations and time-domain waveforms of the bifurcation diagram, phase diagram, Poincaré cross section, inductor current, and output voltage to obtain the variation law of the amplitude and frequency of the chaotic oscillation disturbance of the converter.

2. The distributed power supply anti-islanding protection method as described in claim 1, characterized in that, The differences in electrical quantities of the distribution network include: microgrid voltage, frequency, power, and short-circuit capacity.

3. The distributed power supply anti-islanding protection method as described in claim 1, characterized in that, The method based on 5G wireless communication, through a preset tree search algorithm and the optimized topology, performs station-side islanding judgment on the distribution network to obtain the judgment result, including: optimizing the number of the tree search algorithm according to the correlation properties of the newly added branch and the non-zero injection element of factor decomposition to obtain the initial tree search algorithm; Based on the adjacency matrix to store the electrical primary wiring topology node information, the tree search path of the initial tree search algorithm is optimized according to the voltage level characteristics of the power system to obtain the preset tree search algorithm; Based on 5G wireless communication, the distribution network is used to determine islanding on the station side through the preset tree search algorithm and the optimized topology structure to obtain the determination result.

4. The distributed power supply anti-islanding protection method as described in claim 3, characterized in that, The step of optimizing the tree search algorithm based on the association properties of the newly added branches and the non-zero injected elements of factorization to obtain the initial tree search algorithm includes: improving the representation of the optimized topology based on the highly sparse characteristics of the adjacency matrix of the optimized topology to obtain the improved adjacency matrix. The numbering of the tree search algorithm is optimized based on the improved adjacency matrix, the association properties of newly added branches and non-zero injected elements in factorization, to obtain the initial tree search algorithm.

5. The distributed power supply anti-islanding protection method according to any one of claims 1 to 4, characterized in that, The step of executing an alarm and locking the protection of the distribution network when the judgment result determines that the circuit breaker position is abnormal or invalid includes: when the judgment result determines that the circuit breaker position is abnormal or invalid, determining whether to execute an alarm and lock the protection of the distribution network in conjunction with the circuit breaker position fault tolerance verification and anti-misoperation mechanism.

6. A distributed power supply anti-islanding protection system based on the method described in any one of claims 1-5, characterized in that, The distributed power supply anti-islanding protection system includes: The acquisition module is used to acquire the difference characteristics of electrical quantities of the distribution network based on a preset distribution network topology diagram and a preset distributed power source nonlinear electrical model; The generation module is used to acquire detection signals based on the feature patterns of the differential features using a preset active detection method, and to generate detection results based on the detection signals. The correction module is used to perform weight correction and fusion on the detection results according to a preset information fusion method and weight allocation method, so as to obtain the optimized topology of the power distribution network. The judgment module is used to perform station-side islanding judgment on the distribution network based on 5G wireless communication, through a preset tree search algorithm and the optimized topology, so as to obtain the judgment result. The execution module is used to execute an alarm and lock out the protection of the power distribution network when the judgment result determines that the circuit breaker position is abnormal or invalid.

7. A distributed power supply anti-islanding protection device, characterized in that, The distributed power anti-islanding protection device includes: a memory, a processor, and a program stored in the memory and executable on the processor. When the program is executed by the processor, it implements the steps of the distributed power anti-islanding protection method as described in any one of claims 1 to 5.

8. A storage medium, characterized in that, The storage medium stores a distributed power supply anti-islanding protection program, which, when executed by a processor, implements the steps of the distributed power supply anti-islanding protection method as described in any one of claims 1 to 5.

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