A simulation modeling analysis method and system for power distribution network protection setting and fault tracing

Abstract

This invention discloses a simulation modeling and analysis method and system for distribution network protection settings and fault tracing, relating to the field of distribution network fault detection and protection technology. The method includes: establishing a main-distribution integrated graphical equivalent network with busbar-feeder-terminal connections as units; obtaining network structure parameter information in the main-distribution integrated graphical equivalent network through simulation modeling; performing online verification of protection and self-healing functions based on the main-distribution integrated graphical equivalent network and the network structure parameter information; obtaining fault characteristic quantities at the time of fault occurrence based on the verification results of the online verification, and accurately judging and handling distribution network faults through the fault characteristic quantities; and optimizing existing distribution network fault defense and handling models by leveraging advanced technologies such as artificial intelligence, innovatively creating and constructing a typical paradigm that integrates artificial intelligence + advanced distribution network tools with professional business, to adapt to the evolution and development of the digital transformation of distribution networks.

Description

Technical Field

[0001] This invention relates to the field of distribution network fault detection and protection technology, and more specifically, to a simulation modeling and analysis method and system for distribution network protection settings and fault tracing. Background Technology

[0002] Due to the complex and variable operating conditions and intricate fault scenarios of power distribution networks, power supply equipment such as distribution lines and transformers often have a very high failure probability, thus severely restricting the reliability of power supply for the "last mile" of people's livelihoods. Therefore, a massive influx of distribution terminals with integrated monitoring and protection functions has entered the distribution network to detect and prevent power distribution faults. However, the protection settings and fault detection of these massive distribution terminals currently face many problems, mainly in three aspects:

[0003] 1. Currently, the protection settings of distribution terminals are often set by the dispatching professionals, but the setting installation and operation and maintenance are controlled by the operation and maintenance professionals. This requires both parties to have a good understanding of the distribution network structure and terminal location, and to carry out protection settings and fault diagnosis and handling in combination with the requirements of the "four characteristics" of protection. There is a certain degree of overlap in the work interface and the technical requirements are too high.

[0004] 2. During the on-site installation and commissioning of numerous distribution terminals, factors such as power outage plans, manpower, and awareness of protection requirements can significantly impact performance. Feedback from operational sites indicates that issues such as the correctness of protection settings and their effectiveness under fault conditions often fall short. The root cause is the lack of fault pre-detection in the protection functions after the protection settings are installed. While terminal commissioning primarily involves point-to-point electrical signal testing, it lacks pre-testing of protection functions under fault conditions. This prevents the complete verification of the entire protection logic chain, including fault waveforms, protection settings, and communication links between terminals and the master station. Consequently, the effectiveness of distribution terminals in detecting and mitigating faults after they occur is often poor.

[0005] 3. Due to the massive access of distribution protection terminals and the adjustment of new and abnormal distribution network topology, the setting of protection settings of distribution terminals usually relies heavily on experienced professionals. This work is usually time-consuming and obviously difficult to adapt to the new operating mode of improving production efficiency.

[0006] Therefore, this application is hereby submitted. Summary of the Invention

[0007] The purpose of this invention is to provide a simulation modeling and analysis method and system for distribution network protection settings and fault tracing. Considering the above-mentioned problems, in order to effectively achieve the effectiveness of distribution network protection settings and the accuracy of fault tracing, this invention optimizes the existing distribution network fault prevention and handling mode by leveraging advanced technologies such as artificial intelligence. It innovatively creates and constructs a typical paradigm that integrates artificial intelligence with advanced distribution network tools and professional business to adapt to the evolution and development of the digital transformation of distribution networks.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0009] Firstly, this application provides a simulation modeling and analysis method for distribution network protection settings and fault source tracing, including the following specific steps:

[0010] A main distribution integrated diagram equivalent network is established with substations as the unit, linking busbars, feeders, and terminals;

[0011] Network structure parameters in the equivalent network of the master-slave integrated graphical model are obtained through simulation modeling.

[0012] Based on the equivalent network of the main and auxiliary integrated diagram and the network structure parameters in the network, online verification of protection and self-healing functions is performed;

[0013] Based on the verification results of online verification, the fault characteristic quantities at the time of the fault occurrence are obtained, and the fault characteristic quantities are used to accurately judge and handle the faults in the distribution network.

[0014] Based on the above technical solution, the present invention can be further improved as follows.

[0015] Furthermore, the equivalent network of the aforementioned master-slave integrated graphical model is established in the following way:

[0016] Extract the installation location and upstream and downstream attributes of the primary and secondary integrated switchgear in the PMS3.0 system and / or dispatch automation system for substation busbars, 10kV feeders and single-line diagrams;

[0017] Extract the location of the distribution transformer from the single-line diagram of the same source system, extract the model and parameters of the distribution transformer from the PMS3.0 system, and extract the load information of the transformer in the same source system.

[0018] The NetworkX diagram generation package, a mainstream Python tool, is used to generate diagrams. According to the structure of the diagram, the busbars, integrated primary and secondary switches, transformer substations, and loads are regarded as nodes, and the connections connecting the nodes are regarded as lines. The force-directed layout algorithm is used to automatically generate the position coordinates of the nodes and lines. Then, the diagram generation package is used to form an equivalent network of main and distribution integrated diagram model that is extracted from the complex single-line diagram and is related to the busbar-feeder-terminal.

[0019] Furthermore, the aforementioned network structure parameter information is obtained through the following methods:

[0020] On the substation side, a neutral point is introduced through grounding to form an electrical connection with the 10kV power distribution system, and a three-phase current source injection device for power electronics modification is introduced through this electrical point.

[0021] The three-phase current source injection device injects non-power frequency nth harmonic currents into phases A, B, and C of the 10kV distribution system. The distribution automation cloud master station records the waveform information of each primary and secondary integrated switch of each feeder, extracts the harmonic voltage and harmonic current, and calculates the equivalent harmonic impedance of the section based on the harmonic voltage and harmonic current of the upstream and downstream terminals, and then calculates the power frequency impedance.

[0022] Furthermore, the specific network structure parameters mentioned above are as follows: ; ; In the formula, Representing the upstream primary and secondary integrated complete set of switches The nth harmonic voltage of the phase; , and The first The three-phase nth harmonic voltage; Represents the downstream primary and secondary integrated switchgear. The nth harmonic voltage of the phase, ; , and The first The three-phase nth harmonic voltage; For the first The nth harmonic current of the phase; and These are the nth harmonic currents of phases A, B, and C, respectively. For the first two adjacent terminals upstream and downstream The power frequency impedance of the phase; and (·)and (·) are mathematical operators for calculating the real and imaginary parts of complex numbers, respectively.

[0023] Furthermore, the online verification of protection and self-healing functions based on the equivalent network of the main-distribution integrated diagram and the network structure parameter information in the network is achieved through the following steps:

[0024] Based on the equivalent network and network structure parameter information of the main and distribution integrated diagram, the protection settings of the primary and secondary integrated switchgear of each feeder in the main and distribution integrated diagram are calculated according to the speed, selectivity, sensitivity and reliability of the relay protection.

[0025] When each primary and secondary integrated switch is connected to the network, the protection settings are installed and the alarm function is enabled first. After setting the initial conditions, the fault recording files of different intensities are sent to each switch one by one by the distribution automation master station. The protection function of the primary and secondary integrated switch is correctly enabled based on whether each primary and secondary integrated switch sends the protection message.

[0026] Through the distribution automation master station, fault recording files for both intra-zone and extra-zone types are simultaneously distributed to different distribution automation terminals on different feeders. Based on whether each terminal sends protection messages, it is determined whether the primary and secondary integrated switchgear are correctly coordinated.

[0027] Furthermore, the above-mentioned accurate assessment and troubleshooting of distribution network faults through fault characteristic quantities is achieved through the following steps:

[0028] Standardized waveform recall commands are issued to all distribution automation terminals that synchronously upload waveform recording completion signals under the same bus and at the time of the fault.

[0029] The main station uses the waveform analysis module to standardize and analyze the waveform files sent by each terminal, and extract fault characteristic quantities. The fault characteristic quantities include at least: instantaneous values ​​of three-phase current, instantaneous values ​​of three-phase voltage, zero-sequence current, zero-sequence voltage, fault component current, fault component voltage, as well as the effective value, peak value, and harmonic content of the characteristic quantities.

[0030] By judging the phase relationship between zero-sequence current and zero-sequence voltage and combining it with the fault component method, non-faulty lines are eliminated.

[0031] For the identified faulty line, analyze the waveform files of all its distribution automation terminals one by one, including the three-phase voltage imbalance, zero-sequence voltage amplitude, and zero-sequence current harmonic distortion rate, in order to determine the ground fault type, which includes metallic grounding and non-metallic grounding.

[0032] The fault direction of each terminal is calculated, and the fault direction judgment results of all terminals are combined. The topological relationship of the equivalent network of the main distribution integrated diagram is combined with the interval positioning algorithm to locate the fault section and determine the results of high fault tolerance and accurate judgment and handling of distribution network faults.

[0033] Furthermore, the effective values ​​of the above-mentioned characteristic quantities are calculated using the following formula: ; In the formula, For the effective value of the characteristic quantity, The sampled values ​​of the feature quantity The sampling period.

[0034] Secondly, this application provides a simulation modeling and analysis system for distribution network protection settings and fault source tracing, applied to the simulation modeling and analysis method for distribution network protection settings and fault source tracing as described in any of the first aspects, including:

[0035] The diagram construction module is used to establish an equivalent network of main and distribution integrated diagrams with substations as the unit, which is associated with busbars, feeders and terminals.

[0036] The parameter information calculation module is used to obtain network structure parameter information in the equivalent network of the master-distributor integrated graphical model through simulation modeling.

[0037] The online verification module is used to perform online verification of protection and self-healing functions based on the equivalent network of the main and auxiliary integrated diagram and the network structure parameters in the network.

[0038] The analysis and investigation module is used to obtain fault characteristic quantities at the time of fault occurrence based on the verification results of online verification, and to conduct accurate analysis and investigation of distribution network faults through fault characteristic quantities.

[0039] Thirdly, this application provides an electronic device, including: at least one processor, at least one memory, and a data bus;

[0040] In this system, the processor and memory communicate with each other via a data bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute a simulation modeling and analysis method for power distribution network protection setting and fault tracing, as described in any of the first aspects.

[0041] Fourthly, this application provides a non-transitory computer-readable storage medium that stores computer instructions, which cause the computer to execute a simulation modeling and analysis method for distribution network protection settings and fault tracing as described in any of the first aspects.

[0042] Compared with the prior art, the present invention has at least the following beneficial effects:

[0043] In this application, firstly, an equivalent diagram model is established to link the "substation busbar-feeder-distribution terminal" at the substation level, avoiding the impact of branching lines without terminals on protection settings. Secondly, operating parameters such as line type, upstream and downstream terminal locations, neutral grounding method, and busbar operation mode are extracted. An equivalent distribution network is constructed using a simulation engine, simulating single-phase and three-phase short-circuit fault types at different locations in the network topology. Fault electrical acquisition information for different terminals is recorded. Furthermore, combined with the "four characteristics" requirements of terminal protection, the protection setting sheet for the distribution terminal is automatically generated with one click. Next, based on the equivalent distribution network diagram model and relying on the distribution automation zone IV main station-zone I... The communication link between the master station and the distribution terminals allows for single-point and multi-point transmission of fault waveforms from the master station cloud. This enables verification of the judgment logic and fault self-healing recovery capabilities of the protection of a massive number of connected distribution terminals. Finally, at the distribution automation master station, based on the equivalent distribution network topology and fault event information such as fault messages and fault waveforms from multiple terminals after a fault occurs, a comprehensive fault judgment is performed using multiple protection methods. This avoids the problem of misjudgment by a single terminal protection due to factors such as reversed polarity of the distribution terminal. It also improves the accuracy of fault judgment by using multi-point judgment to correct the fault occurrence section, effectively saving time in fault investigation and helping to ensure the people's electricity needs for a better life.

[0044] This invention uses a graphical model-based distribution network simulation modeling method as its core support, breaking away from the traditional technical limitations of relying on manual experience for protection settings and lacking multi-point verification for fault source tracing. Relying on the cloud-edge collaborative architecture of the distribution automation master station, it constructs a closed-loop system of "graphical model equivalent network - simulation modeling - online verification - accurate judgment" to achieve a dual breakthrough in intelligent distribution network protection settings and accurate fault source tracing. Attached Figure Description

[0045] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a flowchart of the analysis method in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the construction of the equivalent distribution network model in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram illustrating the online verification of the multi-level protection and self-healing functions of the power distribution master station and terminals in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of a high-fault-tolerant and accurate fault assessment and handling mechanism for distribution network faults in a master station diagram embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of the embodiments of the present invention, "multiple" means at least two.

[0054] Example 1: This example provides a simulation modeling and analysis method for distribution network protection settings and fault source tracing, such as... Figure 1 As shown, the specific steps include the following:

[0055] S1, using substations as units, establishes a main-distribution integrated equivalent network model that links busbars, feeders, and terminals.

[0056] Optional, such as Figure 2 As shown, the equivalent network of the above master-slave integrated graphical model is established in the following way:

[0057] S11 extracts the installation location and upstream and downstream attributes of the primary and secondary integrated switchgear from the PMS3.0 production system and the dispatch automation system.

[0058] S12, extract the location of the distribution transformer from the single-line diagram of the same source system, extract the model and parameters of the distribution transformer from the PMS3.0 system, and extract the load information of the transformer in the same source system.

[0059] S13, combined with the mainstream Python tool NetworkX diagram generation package, treats buses, integrated primary and secondary switchgear, transformer substations, and loads as nodes according to the diagram structure, and considers the connections between these nodes as lines. A force-directed layout algorithm is used to automatically generate the position coordinates of nodes and lines. Finally, this diagram generation package forms an equivalent "bus-feeder-terminal" integrated main and distribution network model extracted from the complex single-line diagram. (See [link to documentation]). Figure 2 .

[0060] S2 obtains network structure parameter information in the equivalent network of the master-slave integrated graphical model through simulation modeling.

[0061] Optionally, the above network structure parameter information can be obtained in the following ways:

[0062] S21, on the substation side, the neutral point is introduced through the grounding transformer to form an electrical connection with the 10kV power distribution system, and then the three-phase current source injection device of the power electronics modification is introduced through the electrical point to realize the three-phase current injection regulation of the three-phase power distribution system.

[0063] S22, through the three-phase current source injection device, non-power frequency nth harmonic currents are injected into phases A, B and C of the 10kV distribution system respectively. Then, the waveform information of each primary and secondary integrated switch of each feeder is recorded by the distribution automation cloud master station, and the harmonic voltage and harmonic current are extracted. Based on the harmonic voltage and harmonic current of the upstream and downstream terminals, the equivalent harmonic impedance of the interval can be calculated, and the power frequency impedance can be further calculated.

[0064] Specifically, the network structure parameters mentioned above are as follows: ; ; In the formula, Representing the upstream primary and secondary integrated complete set of switches The nth harmonic voltage of the phase; , and The first The three-phase nth harmonic voltage; Represents the downstream primary and secondary integrated switchgear. The nth harmonic voltage of the phase, ; , and The first The three-phase nth harmonic voltage; For the first The nth harmonic current of the phase; and These are the nth harmonic currents of phases A, B, and C, respectively. For the first two adjacent terminals upstream and downstream The power frequency impedance of the phase; and (·)and (·) are mathematical operators for calculating the real and imaginary parts of complex numbers, respectively.

[0065] S3 performs online verification of protection and self-healing functions based on the equivalent network of the main and auxiliary integrated diagram and the network structure parameter information in the network.

[0066] Optionally, an online verification method for the protection and self-healing functions of the multi-level linkage between the power distribution master station and terminals includes three steps:

[0067] S31. Combining the simplified equivalent model from step S1 and the network structure parameter information from step S2, calculate the protection settings of the primary and secondary integrated switches for each feeder in the equivalent model based on the speed, selectivity, sensitivity, and reliability of the relay protection.

[0068] S32, when each primary and secondary integrated switch is connected to the network, the protection setting value is downloaded and the alarm function is enabled first. After setting the above initial conditions, relying on the distribution automation master station, fault recording files of different intensities are sent to each switch one by one. Based on whether each switch sends a protection message, it is determined whether the primary and secondary integrated switch has correctly enabled the protection function.

[0069] Based on S32, S33 simultaneously distributes fault recording files (both intra- and extra-zone) to different distribution automation terminals on different feeders through the distribution automation master station. It determines whether the primary and secondary integrated switches are correctly coordinated based on whether each terminal sends protection messages, thus realizing the automatic fault self-healing function.

[0070] S4 obtains fault characteristic quantities at the time of fault occurrence based on the verification results of online verification, and uses the fault characteristic quantities to accurately judge and handle the faults in the distribution network.

[0071] Optional, the master-station-based, model-based distribution network fault high-fault-tolerance, accurate judgment and handling mechanism includes two parts:

[0072] S41. After a fault occurs, the distribution automation master station triggers the fault waveform recording and detection process. It issues standardized waveform detection commands to all distribution automation terminals on the same bus that simultaneously uploaded waveform recording completion signals at the time of the fault. The master station uses the waveform analysis module to perform standardized analysis on the waveform files uploaded by each terminal, extracting fault characteristic quantities. Core characteristic quantities include: instantaneous values ​​of three-phase current, instantaneous values ​​of three-phase voltage, zero-sequence current, zero-sequence voltage, and fault component current and fault component voltage. Simultaneously, it calculates derived parameters such as the effective value, peak value, and harmonic content of the characteristic quantities, using the following formulas: ; In the formula: For the effective value of the characteristic quantity, These are the sampled values ​​of the feature quantity.

[0073] S42, based on the fault feature quantities extracted in S41, uses a fault line selection algorithm to locate the faulty line: by judging the phase relationship between zero-sequence current and zero-sequence voltage (satisfying... The lines identified as fault candidate lines are further screened using the fault component method to exclude non-faulty lines. For the identified faulty lines, the waveform files of all their distribution automation terminals are analyzed one by one, with a focus on analyzing the three-phase voltage imbalance. ( This is the effective value of the positive sequence voltage. Using key parameters such as the effective value of negative sequence voltage, the amplitude of zero sequence voltage, and the harmonic distortion rate of zero sequence current, the grounding fault type (metallic grounding, non-metallic grounding) is determined. By calculating the fault direction of each terminal, and combining the fault direction judgment results of all terminals, and combining the topological relationship of the equivalent network of the main distribution integrated model of "bus-feeder-terminal", the fault section is located by using the interval positioning algorithm, and finally the high fault tolerance and accurate judgment and handling of distribution network faults are realized.

[0074] The method of the present invention will be further illustrated by the following examples, such as... Figure 3 The diagram shows the feeders of busbar I in an example transformer. CX is the outgoing line switch, and FD1, FD2, FD3, and FD4 are the section switches. Both the outgoing and section switches have waveform recording capabilities. Based on the topology of each switch, the protection settings, such as the overcurrent stage I setting and the zero-sequence overcurrent stage I setting, are calculated for each switch. Settings are then downloaded to switches CX, FD1, and FD2, and alarm functions are enabled. Fault waveform files are sequentially sent to switches CX, FD1, and FD2 via the distribution automation master station. Upon receiving the fault waveform files, the switches send alarm signals to the master station. The distribution automation master station then simultaneously sends fault waveforms within the protection zone to switches CX, FD1, and FD2, and fault waveforms outside the protection zone to switches FD3 and FD4. Switches CX, FD1, and FD2 send alarm signals to the master station. This confirms that the primary and secondary integrated switch settings and protection actions are correctly configured.

[0075] like Figure 4The diagram shows the feeders of the example transformer bus I, where CX is the outgoing line switch, and FD1, FD2, FD3, and FD4 are the section switches. Both the outgoing and section switches have waveform recording capabilities. The red lightning bolt indicates the location of the fault. At a certain moment, switches CX on lines 1, 2, and 3, and all switches on line 4, send waveform recording completion signals. The main station system then issues a waveform recall command to all intelligent terminals sending waveform recording completion (SOE) information within three minutes before and after that point, and collects, organizes, and analyzes the waveform files according to the switches, extracting characteristic quantities. Comparison of the zero-sequence current amplitude in the analyzed waveforms reveals that the zero-sequence current amplitude of the switches on line 4 is generally greater than that of the other three lines. Therefore, the fault point is determined to be on line 4. Then, a ground fault analysis is performed on the waveform files of all switches on line 4. The fault analysis results show that the waveforms of switches CX, FD1, and FD2 on line 4 are positive ground fault waveforms, while the waveforms of switches FD3, FD4, and FD5 are negative ground fault waveforms. Combined with… Figure 4 It can be seen that the fault point is between switches FD2 and FD3 and FD5.

[0076] Example 2: This application provides a simulation modeling and analysis system for distribution network protection settings and fault tracing, applied to the simulation modeling and analysis method for distribution network protection settings and fault tracing in Example 1, including:

[0077] The diagram construction module is used to establish an equivalent network of main and distribution integrated diagrams with substations as the unit, which is associated with busbars, feeders and terminals.

[0078] The parameter information calculation module is used to obtain network structure parameter information in the equivalent network of the master-distributor integrated graphical model through simulation modeling.

[0079] The online verification module is used to perform online verification of protection and self-healing functions based on the equivalent network of the main and auxiliary integrated diagram and the network structure parameters in the network.

[0080] The analysis and investigation module is used to obtain fault characteristic quantities at the time of fault occurrence based on the verification results of online verification, and to conduct accurate analysis and investigation of distribution network faults through fault characteristic quantities.

[0081] Example 3: This application provides an electronic device, including: at least one processor, at least one memory, and a data bus;

[0082] In this system, the processor and the memory communicate with each other via a data bus; the memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute a simulation modeling and analysis method for power distribution network protection setting and fault tracing, as described in Example 1.

[0083] Example 4: This application provides a non-transitory computer-readable storage medium that stores computer instructions. The computer instructions enable the computer to execute a simulation modeling and analysis method for distribution network protection settings and fault tracing as described in Example 1.

[0084] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0085] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0087] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0088] Those skilled in the art will understand that all or part of the steps in the above facts and methods can be implemented by a program instructing related hardware. The program or the program described therein can be stored in a computer-readable storage medium. When the program is executed, it includes the following steps: at this time, the corresponding method steps are introduced. The storage medium can be ROM / RAM, magnetic disk, optical disk, etc.

[0089] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A simulation modeling and analysis method for distribution network protection settings and fault source tracing, characterized in that, The specific steps include the following: A main distribution integrated diagram equivalent network is established with substations as the unit, linking busbars, feeders, and terminals; The network structure parameter information in the equivalent network of the master-slave integrated graphical model is obtained by simulation modeling. Based on the equivalent network of the main and auxiliary integrated diagram and the network structure parameter information in the network, online verification of protection and self-healing functions is performed; Based on the verification results of the online verification, the fault characteristic quantity at the time of the fault occurrence is obtained, and the fault characteristic quantity is used to accurately judge and handle the fault in the distribution network.

2. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 1, characterized in that, The equivalent network of the master-slave integrated graphical model is established in the following way: Extract the installation location and upstream and downstream attributes of the primary and secondary integrated switchgear in the PMS3.0 system and / or dispatch automation system for substation busbars, 10kV feeders and single-line diagrams; Extract the location of the distribution transformer from the single-line diagram of the same source system, extract the model and parameters of the distribution transformer from the PMS3.0 system, and extract the load information of the transformer in the same source system. The NetworkX diagram generation package, a mainstream Python tool, is used to generate diagrams. According to the structure of the diagram, the busbars, integrated primary and secondary switches, transformer substations, and loads are regarded as nodes, and the connections connecting the nodes are regarded as lines. The force-directed layout algorithm is used to automatically generate the position coordinates of the nodes and lines. Then, the diagram generation package is used to form an equivalent network of main and distribution integrated diagram model that is extracted from the complex single-line diagram and is related to the busbar-feeder-terminal.

3. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 1, characterized in that, The network structure parameter information is obtained through the following methods: On the substation side, a neutral point is introduced through grounding to form an electrical connection with the 10kV power distribution system, and a three-phase current source injection device for power electronics modification is introduced through this electrical point. The three-phase current source injection device injects non-power frequency nth harmonic currents into phases A, B, and C of the 10kV distribution system. The distribution automation cloud master station records the waveform information of each primary and secondary integrated switch of each feeder, extracts the harmonic voltage and harmonic current, and calculates the equivalent harmonic impedance of the section based on the harmonic voltage and harmonic current of the upstream and downstream terminals, and then calculates the power frequency impedance.

4. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 3, characterized in that, The network structure parameter information is specifically as follows: ； ； In the formula, Representing the upstream primary and secondary integrated complete set of switches The nth harmonic voltage of the phase; , and The first The three-phase nth harmonic voltage; Represents the downstream primary and secondary integrated switchgear. The nth harmonic voltage of the phase, ; , and The first The three-phase nth harmonic voltage; For the first The nth harmonic current of the phase; and These are the nth harmonic currents of phases A, B, and C, respectively. For the first two adjacent terminals upstream and downstream The power frequency impedance of the phase; and (·)and (·) are mathematical operators for calculating the real and imaginary parts of complex numbers, respectively.

5. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 1, characterized in that, The online verification of protection and self-healing functions based on the equivalent network of the main-distribution integrated diagram and the network structure parameter information in the network is achieved through the following steps: Based on the equivalent network of the main and distribution integrated diagram and the network structure parameter information, the protection settings of the primary and secondary integrated switchgear of each feeder in the main and distribution integrated diagram are calculated according to the speed, selectivity, sensitivity and reliability of the relay protection. When each primary and secondary integrated switch is connected to the network, the protection settings are installed and the alarm function is enabled first. After setting the initial conditions, the fault recording files of different intensities are sent to each switch one by one by the distribution automation master station. The protection function of the primary and secondary integrated switch is correctly enabled based on whether each primary and secondary integrated switch sends the protection message. Through the distribution automation master station, fault recording files for both intra-zone and extra-zone types are simultaneously distributed to different distribution automation terminals on different feeders. Based on whether each terminal sends protection messages, it is determined whether the primary and secondary integrated switchgear are correctly coordinated.

6. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 1, characterized in that, The accurate assessment and troubleshooting of distribution network faults using the aforementioned fault characteristic quantities are achieved through the following steps: Standardized waveform recall commands are issued to all distribution automation terminals that synchronously upload waveform recording completion signals under the same bus and at the time of the fault. The main station performs standardized analysis on the waveform files sent by each terminal through the waveform analysis module to extract fault characteristic quantities. The fault characteristic quantities include at least: instantaneous values ​​of three-phase current, instantaneous values ​​of three-phase voltage, zero-sequence current, zero-sequence voltage, fault component current, fault component voltage, as well as the effective value, peak value, and harmonic content of the characteristic quantities. By judging the phase relationship between zero-sequence current and zero-sequence voltage and combining it with the fault component method, non-faulty lines are eliminated. For the identified faulty line, analyze the waveform files of all its distribution automation terminals one by one, including the three-phase voltage imbalance, zero-sequence voltage amplitude, and zero-sequence current harmonic distortion rate, in order to determine the ground fault type, which includes metallic grounding and non-metallic grounding. The fault direction of each terminal is calculated, and the fault direction judgment results of all terminals are combined. The topological relationship of the equivalent network of the main distribution integrated diagram is combined with the interval positioning algorithm to locate the fault section and determine the results of high fault tolerance and accurate judgment and handling of distribution network faults.

7. The simulation modeling and analysis method for distribution network protection setting and fault source tracing according to claim 6, characterized in that, The effective value of the characteristic quantity is calculated using the following formula: ； In the formula, For the effective value of the characteristic quantity, The sampled values ​​of the feature quantity The sampling period.

8. A simulation modeling and analysis system for distribution network protection settings and fault source tracing, characterized in that, include: The diagram construction module is used to establish an equivalent network of main and distribution integrated diagrams with substations as the unit, which is associated with busbars, feeders and terminals. The parameter information calculation module is used to obtain network structure parameter information in the equivalent network of the master-supplier integrated graph model through simulation modeling. The online verification module is used to perform online verification of protection and self-healing functions based on the equivalent network of the main-distribution integrated diagram and the network structure parameter information in the network. The analysis and investigation module is used to obtain the fault characteristic quantity when the fault occurs based on the verification result of the online verification, and to conduct accurate analysis and investigation of the distribution network fault through the fault characteristic quantity.

9. An electronic device, characterized in that, include: At least one processor, at least one memory, and a data bus; The processor and the memory communicate with each other via the data bus. The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute a simulation modeling and analysis method for distribution network protection setting and fault tracing as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions, which cause the computer to execute the simulation modeling and analysis method for distribution network protection setting and fault tracing as described in any one of claims 1-7.

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