Power grid bus protection method and system combined with voltage sag traceability, and medium

Abstract

The invention provides a power grid bus protection method and system combined with voltage sag traceability and a medium, and relates to the technical field of bus protection, and the method comprises the steps: collecting a first bus protection device and a second bus protection device of an upstream circuit and a downstream circuit, carrying out the bidirectional voltage sag wrong conduction relation analysis under the triggering of voltage sag protection, and generating a bidirectional wrong conduction relation; establishing a data sharing channel; monitoring the voltage sag behavior of the first bus circuit by the first bus protection device, performing traceability analysis, sharing a traceability result with the second bus protection device through the sharing channel, and calling a bidirectional false conduction relation to judge whether false conduction exists or not; and if not, the first bus protection device performs circuit protection operation based on the traceability result. The technical problem that unnecessary protection actions are caused due to the fact that the fault source cannot be accurately judged due to lack of voltage sag traceability analysis in the prior art is solved, the bus protection accuracy and reliability are improved, misoperation is reduced, and then the stability of a power grid is improved.

Description

Technical Field

[0001] The present application relates to the technical field of busbar protection, and in particular to a method, system and medium for power grid busbar protection combined with voltage sag tracing. Background Art

[0002] Grid busbar protection is an important part of power system relay protection. It is mainly used to detect busbar faults and take corresponding protection measures to ensure the safe and stable operation of the power system.

[0003] Currently, power grid busbar protection primarily relies on differential protection, directional protection, and low-voltage and low-frequency protection. These methods rely primarily on instantaneous changes in current and voltage to identify faults. However, in complex power grid environments, voltage sags may be caused by fault propagation from neighboring areas rather than actual faults within the region. In such cases, relying solely on instantaneous changes in current and voltage to identify faults is difficult to effectively distinguish between actual faults, leading to misjudgment of the fault source, which in turn triggers unnecessary protection actions, causing false tripping, power outages, and grid stability. Summary of the Invention

[0004] The present application provides a power grid busbar protection method, system and medium combined with voltage sag tracing, which solves the technical problem that the existing technology cannot accurately determine the source of the fault due to the lack of voltage sag tracing analysis, thereby causing unnecessary protection actions. It achieves the technical effect of improving the accuracy and reliability of busbar protection, reducing misoperation, and thus improving the stability of the power grid.

[0005] In view of the above problems, on the one hand, the present application provides a power grid bus protection method combined with voltage sag tracing, the method including: collecting a first bus protection device and a second bus protection device with upstream and downstream circuit relationships in a preset power grid area; performing a bidirectional voltage sag misconduction relationship analysis on the first bus protection device and the second bus protection device under the triggering of voltage sag protection to generate a first bidirectional misconduction relationship; establishing a first data sharing channel between the first bus protection device and the second bus protection device; using the first bus protection device to monitor the voltage sag behavior of the first bus circuit and perform a tracing analysis, sharing the first tracing result with the second bus protection device through the first data sharing channel, calling the first bidirectional misconduction relationship to determine whether there is a voltage sag misconduction; if not, the first bus protection device performs circuit protection operation based on the first tracing result.

[0006] On the other hand, the present application also provides a power grid bus protection system combined with voltage sag tracing, the system including: an acquisition module for collecting the first bus protection device and the second bus protection device having an upstream and downstream circuit relationship in a preset power grid area; a relationship analysis module for performing a bidirectional voltage sag misconduction relationship analysis on the first bus protection device and the second bus protection device under the triggering of voltage sag protection, and generating a first bidirectional misconduction relationship; a data sharing module for establishing a first data sharing channel between the first bus protection device and the second bus protection device; a misconduction judgment module for monitoring the voltage sag behavior of the first bus circuit with the first bus protection device and performing a tracing analysis, sharing the first tracing result with the second bus protection device through the first data sharing channel, and calling the first bidirectional misconduction relationship to determine whether there is a misconduction with a voltage sag; a circuit protection module for, if not, the first bus protection device performing a circuit protection operation based on the first tracing result.

[0007] In a third aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-mentioned power grid bus protection method combined with voltage sag tracing.

[0008] One or more technical solutions provided in this application have at least the following beneficial effects:

[0009] Acquire information about busbar protection devices with associated upstream and downstream circuits within the power grid area to fully understand the operating status of the upstream and downstream busbars, providing data support for subsequent voltage sag source tracing. By analyzing the propagation path of the voltage sag between the upstream and downstream busbars, determine whether the voltage sag is caused by a local fault or external transmission, thereby identifying possible misconduction. Establish an information sharing mechanism between the first and second busbar protection devices, enabling rapid exchange of tracing analysis results between the different protection devices, improving judgment accuracy and response speed. The first busbar protection device monitors local voltage sags and performs tracing analysis, sending the analysis results to the second busbar protection device via a shared channel. Combining the bidirectional misconduction relationship, it determines whether the voltage sag is a misconduction phenomenon. Upon confirming that the voltage sag is not a misconduction, the first busbar protection device executes the corresponding circuit protection measures based on the tracing analysis results, ensuring the accuracy of the protection action, avoiding misoperation, and ensuring the safe and stable operation of the power grid.

[0010] In summary, this application improves the accuracy and reliability of protection, and enhances the coordination and real-time nature of protection through bidirectional misconduction relationship analysis and data sharing mechanisms. Through precise traceability analysis, the source of faults can be quickly and accurately determined, avoiding unnecessary protection actions, thereby improving the stability of the power grid, achieving precise and intelligent busbar protection, and providing a strong guarantee for the safe operation of modern power grids.

[0011] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A flow chart of a grid busbar protection method combined with voltage sag tracing provided in an embodiment of the present application.

[0013] Figure 2 A schematic diagram of a flow chart for obtaining a first bidirectional misconduction relationship in a power grid bus protection method combined with voltage sag tracing provided in an embodiment of the present application.

[0014] Figure 3 A schematic diagram of the structure of a power grid bus protection system combined with voltage sag tracing provided in an embodiment of the present application.

[0015] Description of the accompanying drawings: acquisition module 10, relationship analysis module 20, data sharing module 30, misconduction judgment module 40, circuit protection module 50. DETAILED DESCRIPTION

[0016] The embodiments of the present application provide a power grid busbar protection method, system and medium combined with voltage sag tracing, thereby solving the technical problem of the prior art that the source of the fault cannot be accurately determined due to the lack of voltage sag tracing analysis, thereby causing unnecessary protection actions. The technical effect of improving the accuracy and reliability of busbar protection, reducing misoperation, and thus improving the stability of the power grid is achieved.

[0017] Example 1, as Figure 1 As shown, an embodiment of the present application provides a power grid bus protection method combined with voltage sag tracing, the method comprising:

[0018] Step S100: collecting information of a first busbar protection device and a second busbar protection device having an upstream and downstream circuit relationship in a preset power grid area.

[0019] Specifically, the preset power grid area refers to a specific area range that is pre-set in the power grid system, which is composed of multiple substations, transmission lines and distribution networks, and is the management object of the embodiment of the present application. In the preset power grid area, the connection relationship between the busbars is obtained through the circuit diagram or the system topology structure, and the busbars with upstream and downstream relationships are identified (recorded as the first busbar circuit and the second busbar circuit). In combination with tools such as SCADA (data acquisition and monitoring system) or EMS (energy management system), the busbar protection devices corresponding to these busbars (i.e., the first busbar protection device and the second busbar protection device) are determined, and the protection device information on these busbars, such as model, measurement data interface, etc., are collected. Among them, the upstream and downstream circuit relationship refers to the flow direction relationship of the current or voltage in the circuit. In the power grid, the current flows from the power source to the load. Along the direction of the current, for a certain busbar protection device, the circuit part that provides it with electrical energy (current inflow) is the upstream circuit, and the circuit part that receives its output electrical energy (current outflow) is the downstream circuit. For example, in a substation, the main busbar A supplies power to the busbar B. Then A is the upstream busbar of B, and B is the downstream busbar of A. Busbar A is recorded as the first busbar circuit, and the protection device on busbar A is recorded as the first busbar circuit protection device; busbar B is recorded as the second busbar circuit, and the protection device on busbar B is recorded as the second busbar circuit protection device.

[0020] The data of the first busbar protection device and the second busbar protection device with upstream and downstream circuit relationships in the preset power grid area are collected, which provides a specific research object for the subsequent analysis of the voltage sag misconduction relationship. Starting from the local relationship of the power grid system, the busbar protection devices that may have mutual influence can be analyzed in a targeted manner, thereby improving the accuracy and reliability of the busbar protection of the entire power grid.

[0021] Step S200: performing a bidirectional voltage sag misconduction relationship analysis on the first busbar protection device and the second busbar protection device under voltage sag protection triggering to generate a first bidirectional misconduction relationship.

[0022] Specifically, voltage sag refers to a short, sudden drop in voltage in a power grid followed by recovery, typically caused by a fault or load change. Misconduction occurs when a voltage sag is not caused by a local fault but rather propagated from upstream or neighboring power grids, potentially leading to misjudgment and triggering unnecessary protective action.

[0023] In a simulation environment, power system simulation software (such as PSCAD / EMTDC, MATLAB Simulink, or RTDS) is used to simulate a voltage sag scenario. A short-duration fault is applied between bus A (upstream) and bus B (downstream), triggering the voltage sag protection of the first and second bus protection devices. Data such as voltage changes on bus A and bus B are collected using tools such as SCADA systems, PMUs (Phasor Measurement Units), or data loggers. Timing analysis methods are used to compare the onset times of the voltage sags on bus A and bus B, analyzing the voltage sag propagation path between the upstream and downstream buses. If a voltage sag occurs first on bus A, followed by a similar sag on bus B, this could be an A-to-B fault (upstream affecting downstream). If a voltage sag occurs first on bus B, followed by an abnormality on bus A, this could be a B-to-A fault (downstream affecting upstream). If bus A and bus B experience sags simultaneously, or if bus B experiences a sag independently, this indicates that the sag on bus B is unrelated to bus A and is not a fault. According to the above analysis results, a first bidirectional misconduction relationship between busbar A and busbar B is established.

[0024] By analyzing the bidirectional voltage sag misconduction relationship under the voltage sag protection triggering, the possible misconduction relationship between the two busbar protection devices under voltage sag conditions can be accurately identified, providing a basis for avoiding erroneous protection actions caused by misconduction and improving the accuracy of busbar protection.

[0025] Step S300: establishing a first data sharing channel between the first busbar protection device and the second busbar protection device.

[0026] Specifically, the data sharing channel is a communication path for transmitting data between the first busbar protection device and the second busbar protection device, and can be a channel based on wired communication (such as optical fiber communication) or wireless communication (such as short-range wireless communication technology such as ZigBee).

[0027] Based on the communication interface type of the busbar protection device, select the appropriate communication technology to establish a data sharing channel. If the busbar protection device has an Ethernet interface, Ethernet-based wired communication can be used to establish the channel. In terms of hardware, it is necessary to connect the appropriate communication cables or set up a wireless communication module. In terms of software, it is necessary to configure the communication protocol to ensure that data can be correctly transmitted between the two devices. If the busbar protection device has a fiber optic interface, a data sharing channel can be established by laying optical fiber and using power system communication protocols such as IEC 61850 to ensure the accuracy of data transmission.

[0028] The data sharing channel provides a reliable way for information exchange between busbar protection devices, enabling timely sharing of important information such as traceability results, enhancing the coordination of busbar protection devices during the protection process, and helping to more accurately determine the true cause of voltage sags.

[0029] Step S400: Use the first busbar protection device to monitor the voltage sag behavior of the first busbar circuit and perform tracing analysis, share the first tracing result with the second busbar protection device through the first data sharing channel, and call the first bidirectional misconduction relationship to determine whether there is misconduction of voltage sag.

[0030] Specifically, the first busbar protection device monitors the voltage of the first busbar circuit in real time through a built-in voltage sensor. When a voltage sag is detected, it uses timing analysis and historical fault comparison methods to perform a source tracing analysis to determine the starting point of the voltage sag and generate a first tracing result. The tracing result is then sent to the second busbar protection device through the first data sharing channel established previously. At the same time, the first bidirectional misconduction relationship generated previously is called and compared with the first tracing result to determine whether there is misconduction of the voltage sag. If the sag tracing result shows that it is transmitted from upstream, the protection action is not triggered, otherwise the protection strategy continues to be executed.

[0031] The above steps comprehensively utilize the monitoring and traceability analysis capabilities of the first busbar protection device, as well as the information sharing and misconduction relationship between busbar protection devices, to accurately determine whether the voltage sag is misconduction, thereby improving the accuracy of fault judgment.

[0032] Step S500: If not, the first busbar protection device performs a circuit protection operation based on the first tracing result.

[0033] Specifically, if the voltage sag tracing results indicate that it is not caused by misconduction, the first busbar protection device determines the fault type and location based on the first tracing results and implements a pre-set circuit protection strategy. For overcurrent faults, the circuit breaker can be controlled to trip, disconnecting the corresponding faulty line; for undervoltage faults, the voltage can be adjusted by activating a voltage regulator or switching to a backup power source. For example, in an industrial power grid, if the tracing results indicate that a short circuit in a branch caused a busbar voltage sag, the first busbar protection device will trip the circuit breaker connected to that branch, thereby implementing circuit protection.

[0034] Performing circuit protection operations based on the results of misconduction judgment can effectively protect the bus circuit, improve the accuracy of protection, avoid unnecessary protection actions, and ensure the safe and stable operation of the power grid.

[0035] Furthermore, after establishing the first data sharing channel, the method further includes:

[0036] The second busbar protection device is used to monitor the voltage sag behavior of the second busbar circuit and perform tracing analysis, and the second tracing result is shared with the first busbar protection device through the first data sharing channel. Based on the first bidirectional misconduction relationship, it is determined whether the voltage sag behavior is misconduction with voltage sag; if not, the second busbar protection device performs circuit protection operation based on the second tracing result.

[0037] Specifically, the analysis of voltage sag is not limited to the first busbar protection device. The same traceability analysis is also required for the second busbar protection device, and the analysis results are shared with each other to enhance the accuracy of judgment. The specific execution process is similar to the corresponding traceability analysis and misconduction judgment process of the first busbar protection device. Please refer to the corresponding description.

[0038] After establishing the first data sharing channel, the second busbar protection device uses its own voltage sensor to monitor the voltage, current and other parameters of the second busbar circuit in real time. When a voltage sag is detected, a traceability analysis method similar to that of the first busbar protection device is used to determine the cause of the voltage sag and generate a second traceability result. The second traceability result is then sent to the first busbar protection device using the established first data sharing channel. After the first busbar protection device receives the result, the two devices perform interactive judgment based on the first bidirectional misconduction relationship generated previously. For example, in a regional power grid, the second busbar protection device detects a voltage sag and performs a traceability analysis by analyzing the power flow distribution of the busbar connection line. The result is then shared with the first busbar protection device via the first data sharing channel composed of optical fibers. Both parties then determine whether it is misconduction based on the existing misconduction relationship. If it is determined not to be misconduction, the second busbar protection device will determine the specific fault condition based on the second traceability result and perform the corresponding circuit protection operation.

[0039] For the entire power grid busbar protection system, the above steps further improve the comprehensiveness and accuracy of protection. Through reverse monitoring, traceability analysis, and result sharing by the second busbar protection device, as well as judgment based on misconduction relationships, the mutual influence of voltage sags between the two busbars can be more comprehensively considered, avoiding protection loopholes that may arise from only considering a single direction (from the first busbar to the second busbar). This two-way monitoring and judgment mechanism enables closer collaboration between the two busbar protection devices, enhancing the stability and reliability of the entire power grid when responding to voltage sags.

[0040] Further, such as Figure 2 As shown, step S200 of the embodiment of the present application includes:

[0041] Step S210: performing integrated circuit equivalent modeling on the first busbar protection device and the corresponding first busbar circuit, the second busbar protection device and the corresponding second busbar circuit, and generating an equivalent circuit model.

[0042] Step S220: Based on the equivalent circuit model, perform protection simulations and voltage sag misconduction simulations on the first bus circuit under multiple first voltage sag behaviors, determine the voltage sag conduction relationship misconducted to the second bus circuit, and generate a first forward misconduction relationship.

[0043] Step S230: Based on the equivalent circuit model, perform protection simulation and voltage sag misconduction simulation on the second bus circuit under multiple second voltage sag behaviors, determine the voltage sag misconduction relationship to the first bus circuit, and generate a first reverse misconduction relationship.

[0044] Step S240: constructing the first bidirectional misconduction relationship by using the first forward misconduction relationship and the first reverse misconduction relationship.

[0045] Specifically, circuit equivalent modeling refers to simplifying the busbars, power equipment, and lines of a complex power grid into an equivalent mathematical model in power grid simulation for computational analysis. The relevant parameters of the first busbar protection device, the first busbar circuit, the second busbar protection device, and the second busbar circuit are collected, including the rated voltage of the busbar, the action threshold of the protection device, the resistance and inductance of the line, etc. Then, based on circuit theory knowledge, the representation of each component in the equivalent circuit is determined. For example, for long-distance transmission lines, considering their distributed parameter characteristics, a combination of multiple resistors, inductors, and capacitors is used for equivalent purposes. Simulation tools such as PSCAD and MATLAB Simulink can be used to construct equivalent circuit models to describe the propagation characteristics of voltage sags in the power grid.

[0046] Different voltage sag types, such as three-phase short circuit, single-phase ground fault, and transient load fluctuation, were set. For each voltage sag type, voltage sags of varying magnitudes (e.g., 10%, 20%, 30%), durations (e.g., 0.1, 0.2, 0.5 seconds), and start times were set for the first bus circuit, resulting in various first voltage sag behaviors. Based on the generated equivalent circuit model, simulation software was used to simulate the voltage sag by varying the voltage input parameters of the first bus circuit within the model for each set first voltage sag behavior. The protective action of the first bus protection device and the voltage changes in the second bus circuit were then observed. Through multiple simulations of different voltage sag behaviors, relevant data was collected and analyzed to determine the misconduct relationship from the first bus circuit to the second bus circuit, known as the first positive misconduct relationship. For example, in a simulated industrial power grid equivalent circuit model, a three-phase short circuit was set in the first bus circuit. The activation of the first bus protection device and the abnormal voltage changes in the second bus circuit were observed. Repeated parameter settings were used to determine the positive misconduct relationship.

[0047] Similar to the above steps, multiple second voltage sag behaviors are set. Based on the equivalent circuit model, simulation software is used to simulate voltage sags by varying the voltage input parameters of the second bus circuit for each set second voltage sag behavior. The protective action of the second bus protection device and the voltage changes of the first bus circuit are then observed. Through multiple simulations of different voltage sag behaviors, relevant data is collected and analyzed to determine the misconduct relationship from the second bus circuit to the first bus circuit, namely the first reverse misconduct relationship. For example, in an equivalent circuit model of a city power grid, a 30% voltage drop lasting 0.3 seconds is set for the second bus circuit. The activation of the second bus protection device and the voltage changes of the first bus circuit are observed. Repeatedly setting different parameters to determine the reverse misconduct relationship.

[0048] The obtained first forward misconduction relationship and the first reverse misconduction relationship are integrated to form a complete misconduction relationship, thereby obtaining a first bidirectional misconduction relationship. In terms of data structure, this bidirectional misconduction relationship can be represented in the form of a matrix or a table.

[0049] By establishing a complete two-way misconduction relationship and clarifying the mutual influence relationship between the upstream and downstream bus circuits, a comprehensive basis is provided for accurately judging whether the voltage sag is caused by misconduction in subsequent steps, thereby improving the accuracy and reliability of the entire bus protection scheme when dealing with voltage sag situations.

[0050] Furthermore, step S210 in the embodiment of the present application includes:

[0051] Step S211: collecting first device structural characteristics of the first busbar protection device and first circuit structural characteristics of the corresponding first busbar circuit.

[0052] Step S212: collecting the second device structural characteristics of the second bus protection device and the second circuit structural characteristics of the corresponding second bus circuit.

[0053] Step S213: collecting the connection characteristics of the intermediate circuit between the first bus circuit and the second bus circuit.

[0054] Step S214: performing circuit equivalent modeling based on the first device structure feature, the first circuit structure feature, the second device structure feature, the second circuit structure feature, and the intermediate circuit connection feature to generate the equivalent circuit model.

[0055] Specifically, device structural characteristics refer to characteristics related to the structure within the busbar protection device, such as the type of protection device (primarily overcurrent protection or overvoltage protection), internal circuit structure (such as relay logic circuits or microprocessor-based intelligent circuits), and component parameters (such as relay operating current and operating time). These characteristics affect the functional performance of the protection device in the circuit. Circuit structural characteristics are the structural parameters of the busbar circuit, including the busbar connection method (single busbar segmentation or double busbar, etc.), voltage level (110kV, 35kV, etc.), short-circuit capacity (MVA), line impedance (resistance R, reactance X), load size, etc.

[0056] Use the SCADA system and relay protection monitoring system to collect information related to the first device structural characteristics of the first busbar protection device and the first circuit structural characteristics of the first busbar circuit. Example: Busbar A is a 110kV system that uses dual busbar differential protection and directional overcurrent protection. The corresponding parameters are as follows: Relay protection: differential protection setting 5A, overcurrent setting 200A, line impedance: R = 0.01Ω / km, X = 0.1Ω / km; load: 220MW.

[0057] Similarly, collect the second device structural characteristics of the second busbar protection device and the second circuit structural characteristics of the corresponding second busbar circuit. For example, if busbar B is a 35kV system and uses directional overcurrent and zero-sequence overcurrent protection, the corresponding parameters are as follows: relay protection: overcurrent setting 150A; line impedance: R = 0.02Ω / km, X = 0.15Ω / km; load: 50MW.

[0058] The intermediate circuit is the portion of the power grid that connects the primary busbar circuit to the secondary busbar circuit. It typically consists of transformers, lines, and mutual inductors. The corresponding intermediate circuit connection characteristics include transformer parameters (transformation ratio, short-circuit impedance, etc.), line parameters (transmission distance, loss), and mutual inductor characteristics (CT / PT ratio, accuracy). Using the substation wiring diagram and the power GIS system, the connection topology of busbars A and B is extracted, its impact is quantified, and the equivalent parameters of key equipment such as transformers and lines are calculated. For example, there is a transformer (110 / 35kV, short-circuit impedance 6%) between busbars A (110kV) and B (35kV). The line transmission distance is 10km, and the line impedance is: R = 0.05Ω, X = 0.2Ω.

[0059] Based on the first and second circuit structural characteristics, the busbar circuit portion is represented in the equivalent circuit, such as using equivalent resistance, inductance, and capacitance to represent the busbar and its connecting lines. Based on the first and second device structural characteristics, the protective device is represented using equivalent circuit elements (such as a controllable switch). Then, based on the intermediate circuit connection characteristics, an equivalent portion connecting the first and second busbar circuits is constructed. For example, if there is an intermediate transformer, the transformation relationship in the equivalent circuit is determined based on its transformation ratio. Mathematical modeling tools (MATLAB Simulink, PSCAD) can be used to create an equivalent circuit model.

[0060] The generated equivalent circuit model comprehensively considers the characteristics of all devices and circuits associated with the first and second busbars. This model provides a foundation for subsequent protection simulations and voltage sag misconduction simulations, enabling analysis and research based on a simplified and accurate model, helping to improve the accuracy of the overall voltage sag misconduction relationship analysis.

[0061] Furthermore, the first forward misconduction relationship includes the original voltage sag characteristics of the first bus circuit and the voltage sag characteristics that are misconducted to the second bus circuit; the first reverse misconduction relationship includes the original voltage sag characteristics of the second bus circuit and the voltage sag characteristics that are misconducted to the first bus circuit.

[0062] Specifically, for the first bus circuit or the second bus circuit, the original voltage sag characteristics refer to the initial state characteristics when the voltage sag occurs in the bus circuit, including the voltage drop amplitude, duration, etc. The voltage sag characteristics that are mistakenly transmitted to the second (or first) bus circuit refer to the voltage sag characteristics after being mistakenly transmitted to another bus circuit due to the circuit connection relationship when a voltage sag occurs in one bus circuit. For example, after the voltage sag occurs in the first bus circuit, the voltage drop amplitude and duration observed on the second bus circuit. Since the voltage sag will be affected by circuit elements (such as line resistance, inductance, etc.) during the conduction process, the voltage sag characteristics that are mistakenly transmitted to the second (or first) bus circuit may be different from the original voltage sag characteristics.

[0063] In the process of generating the first forward misconduction relationship, when performing protection simulations and voltage sag misconduction simulations under multiple first voltage sag behaviors on the first bus circuit on the equivalent circuit model, for each simulation setting of the first bus circuit's voltage sag (i.e., original voltage sag characteristics, such as setting a voltage sag amplitude of 10% and a duration of 0.1 seconds), the voltage sag characteristics after misconduction are determined by monitoring the voltage changes of the second bus circuit (e.g., observing that the voltage sag amplitude of the second bus circuit changes to 8% and the duration changes to 0.08 seconds). These original characteristics and misconduction characteristics are recorded and organized to obtain the first forward misconduction relationship.

[0064] When generating the first reverse misconduction relationship, similarly, when performing simulations on the second bus circuit under multiple second voltage sag behaviors, the original voltage sag characteristics of the second bus circuit are set (such as a voltage reduction amplitude of 15%, a duration of 0.15 seconds, etc.), and then the voltage sag characteristics after misconduction are determined by monitoring the voltage changes of the first bus circuit (such as a voltage reduction amplitude of the first bus circuit becomes 12%, a duration of 0.12 seconds, etc.), thereby constructing the first reverse misconduction relationship.

[0065] Clarifying the forward and reverse misconduction relationships, encompassing both the original voltage sag characteristics and the characteristics of the voltage sag after misconduction, provides a deeper understanding of the conduction characteristics of the voltage sag between two busbar circuits. This detailed characteristic information can improve the accuracy of subsequent judgments on whether a voltage sag is misconduction. For example, when voltage sags are actually monitored across two busbar circuits, they can be compared with the characteristics in these relationships to more accurately determine whether misconduction has occurred, helping to improve the reliability of busbar protection devices and the stability of grid operation.

[0066] Furthermore, in step S4, the first bus protection device is used to monitor the voltage sag behavior of the first bus circuit and perform source tracing analysis, including:

[0067] Step S410: Monitor the voltage data of the first bus circuit through the voltage sensor in the first bus protection device to generate first voltage time series data.

[0068] Step S420: Identify the voltage drop amplitude and duration based on the first voltage time series data to generate a first real-time voltage sag feature.

[0069] Step S430: inputting the first real-time voltage sag feature into a voltage sag tracing database for comparison to generate a first protection triggering decision.

[0070] Step S440: Generate the first tracing result based on the first protection triggering decision and the first real-time voltage sag feature.

[0071] Specifically, the voltage sensor in the first busbar protection device continuously measures the voltage of the first busbar circuit and converts the busbar circuit voltage into a corresponding electrical signal. This electrical signal is then collected by the data acquisition system within the protection device at a predetermined sampling frequency and arranged in chronological order to generate first voltage time series data.

[0072] The voltage sag amplitude is the percentage of the bus voltage drop relative to the rated value when a voltage sag occurs. The duration refers to the length of time the voltage remains below a certain threshold. A normal voltage range is set based on the bus's rated voltage and the allowable voltage fluctuation range. Real-time analysis of voltage time series data is performed. When the voltage value is detected to be below the normal range, the voltage sag amplitude is calculated, i.e., the ratio of the current voltage value to the rated voltage value. The start time of the voltage falling below the normal range and the time it takes to return to the normal range are recorded to determine the duration. The identified voltage sag amplitude and duration are integrated into the first real-time voltage sag feature.

[0073] The voltage sag traceability database is a pre-established database based on historical data. It stores various voltage sag conditions that occurred during historical operation, the causes of voltage sags, and the corresponding protection triggering decisions. The protection triggering decision is used to determine whether to trigger the protection function of the first busbar protection device, whether to immediately trigger tripping protection or conduct further monitoring. The first real-time voltage sag feature obtained is matched with the data in the voltage sag traceability database. Each record in the database contains the characteristic range of the voltage sag (e.g., a voltage drop between 10% and 20% and a duration between 0.05 seconds and 0.15 seconds) and the corresponding protection triggering decision (e.g., an alarm but no tripping). The first protection triggering decision is determined by searching for records that match the first real-time voltage sag feature. During the comparison process, data matching algorithms, such as range-based matching algorithms or similarity-based matching algorithms, can be used to ensure that the appropriate protection triggering decision is accurately obtained from the database.

[0074] The first protection trigger decision (e.g., whether to trigger protection, type of protection, etc.) and the first real-time voltage sag characteristics (e.g., voltage drop magnitude, duration, etc.) are integrated to generate a first traceability result containing detailed characteristics and decision information. This generated first traceability result provides a comprehensive basis for subsequent result sharing and misconduction judgment. It includes both the actual voltage sag situation and protection decision information, helping to accurately determine whether misconduction of voltage sag exists when interacting with the second busbar protection device, thereby improving the reliability of the entire busbar protection system.

[0075] Furthermore, the voltage sag tracing database includes multiple groups of historical voltage sag protection triggering data, wherein any group of historical voltage sag protection triggering data includes historical voltage sag characteristics, historical voltage sag factors and historical protection decisions.

[0076] Specifically, the voltage sag traceability database stores multiple sets of historical voltage sag protection trigger data, that is, detailed information on voltage sag events that occurred in the past, for future real-time traceability comparison and protection optimization. Any set of historical voltage sag protection trigger data includes historical voltage sag characteristics, historical voltage sag factors and historical protection decisions. Data related to voltage sags are collected from the historical operation records of the power system. These records can come from power monitoring systems (such as SCADA systems), action records of protection devices, etc. For each historical voltage sag event, record the characteristics of the voltage sag (calculate the magnitude and duration of the sag through the voltage monitoring data at the time), the factors that caused the voltage sag (determined through fault troubleshooting reports, equipment operation logs, etc., such as determining that it was caused by a short-circuit fault on a certain line) and the protection decisions taken at the time (check the action records of the protection device, such as whether it tripped, etc.).

[0077] The collected historical voltage sag characteristics, historical voltage sag factors, and historical protection decisions are organized in a specific format. This can be done in a database table, with each row representing a historical voltage sag event and columns storing information such as historical voltage sag characteristics, historical voltage sag factors, and historical protection decisions. Use a database management system to store this data for easy query and management.

[0078] When a new voltage sag occurs, methods such as Euclidean distance, cosine similarity, and dynamic time warping (DTW) are used to compare the current voltage sag characteristics with historical data in the database to find the most similar historical events. This allows us to refer to historical protection decisions made under similar circumstances and make more accurate protection decisions.

[0079] Furthermore, before the first busbar protection device performs a circuit protection operation based on the first tracing result, the device further includes:

[0080] Step S510: collecting data from a first other protection device located in an upstream circuit of the first busbar protection device within the preset power grid area.

[0081] Step S520: Analyze the voltage sag misconduction relationship of the voltage sag that is unidirectionally transmitted to the first bus protection device in the scenario where the protection logic of the first other protection device is triggered, and generate misconduction relationships of other protection devices.

[0082] Step S530: Establish a second data sharing channel between the first other protection device and the first bus protection device.

[0083] Step S540: Use the first busbar protection device to monitor the voltage sag behavior of the first busbar circuit and perform tracing analysis, share the first tracing result with the first other protection device through the second data sharing channel, call the misconduction relationship of the other protection device to determine whether there is misconduction of voltage sag, and determine whether to perform circuit protection operation based on the judgment result.

[0084] Specifically, the first other protection device refers to a protection device other than the first busbar protection device located in the circuit upstream of the first busbar protection device, such as a line protection device, a transformer protection device, etc. In a preset power grid area, a search and identification is performed along the direction of the circuit upstream of the first busbar protection device to collect the first other protection devices.

[0085] Build a circuit equivalent model of the first other protection device and the first busbar protection device (refer to the modeling method in the previous step). Use this model to simulate various scenarios in which the first other protection device triggers its protection logic. For example, set different fault types and circuit parameters to simulate the operation of the first other protection device during an overcurrent fault and observe the voltage changes of the first busbar protection device in this situation. By simulating different scenarios multiple times and collecting and analyzing relevant data, such as the magnitude and duration of the voltage sag, the misconduct relationship of the other protection device can be generated.

[0086] Based on the power system's communication protocol, a connection is established between the first other protection device and the first busbar protection device using an existing communication network (such as a fiber-optic communication network or Ethernet). A second data sharing channel can be established by configuring the communication interface and setting communication parameters (such as baud rate and IP address). Through this second data sharing channel, the two protection devices can exchange relevant information, such as traceability results and protection device status, enabling collaborative operation and more accurate voltage sag misconduction detection.

[0087] In the first busbar protection device, the first traceability result is packaged according to a predetermined data format. For example, the result can be converted into XML format or a specific binary format. Then, the packaged result is sent to the first other protection device through the second data sharing channel. After receiving the data, the first other protection device unpacks it according to the same format to obtain the first traceability result. Then, both parties make a judgment based on the first traceability result and the misconducting relationship with other protection devices. If it is found that the voltage sag characteristics meet the situation in the misconducting relationship, it is determined that there is misconducting of voltage sag; otherwise, it is determined to be a normal voltage sag situation. According to the judgment result, if there is no misconducting, the circuit protection operation is performed according to the normal protection operation process; if it is a misconducting situation, the circuit protection operation is not performed.

[0088] The above steps are based on the misconduction analysis logic of the aforementioned first busbar device and second busbar protection device, and extend the misconduction analysis scope to the upstream protection device of the first busbar. By sharing the first tracing result and calling the misconduction relationship of other protection devices for judgment, unnecessary circuit protection operations caused by misconduction can be avoided, which helps to improve the operating stability of the entire power grid and the reliability of the protection device, and reduce adverse effects such as the expansion of the power outage scope due to misoperation.

[0089] In summary, the power grid busbar protection method combined with voltage sag tracing provided by the embodiments of the present application has the following beneficial effects:

[0090] This system obtains information about busbar protection devices with upstream and downstream circuit linkages within the power grid, comprehensively understanding the operating status of the upstream and downstream buses and providing data support for subsequent voltage sag traceability. A simulation model is constructed using circuit equivalent modeling. This model is then used to perform voltage sag protection and misconduct simulations. The forward misconduct relationship from the first busbar to the second busbar and the reverse misconduct relationship from the second busbar to the first busbar are determined, ultimately establishing a complete bidirectional misconduct relationship to ensure traceability of misconduct behavior. Based on this bidirectional misconduct relationship, a data sharing channel is established between the first and second busbar protection devices, enabling real-time interaction of traceability analysis results. When a voltage sag occurs, the first busbar protection device collects time-series data using a voltage sensor, calculates the voltage sag characteristics, and compares them with a traceability database to generate a first traceability result. This traceability result is synchronized to the second busbar protection device via the data sharing channel. The bidirectional misconduct relationship is then used to determine whether the voltage sag is caused by misconduct. If not, the first busbar protection device initiates appropriate protective measures. In addition, in order to further improve the traceability accuracy, the embodiment of the present application is extended to the upstream protection device of the first bus, analyzes its misconduction relationship, and establishes a data sharing channel with the upstream protection device. After monitoring the voltage sag behavior of the first bus, the misconduction situation is judged in combination with the upstream data, and finally a decision is made whether to perform a protective action.

[0091] Overall, the embodiments of this application improve the accuracy and reliability of busbar protection, and enhance the coordination and real-time performance of busbar protection through bidirectional misconduction relationship analysis and data sharing mechanisms, combined with precise comparisons in a historical traceability database. Through precise traceability analysis, the source of faults can be quickly and accurately determined, avoiding unnecessary protection actions, thereby improving the stability of the power grid, achieving precise and intelligent busbar protection, and providing a strong guarantee for the safe operation of modern power grids.

[0092] Example 2, as Figure 3 As shown, based on the same inventive concept as the aforementioned embodiment 1, the embodiment of the present application provides a power grid bus protection system combined with voltage sag tracing, the system comprising:

[0093] The acquisition module 10 is used to acquire information of a first busbar protection device and a second busbar protection device having an upstream and downstream circuit relationship in a preset power grid area.

[0094] The relationship analysis module 20 is used to perform a bidirectional voltage sag misconduction relationship analysis on the first busbar protection device and the second busbar protection device under voltage sag protection triggering, and generate a first bidirectional misconduction relationship.

[0095] The data sharing module 30 is configured to establish a first data sharing channel between the first bus protection device and the second bus protection device.

[0096] The misconduction judgment module 40 is used to monitor the voltage sag behavior of the first bus circuit with the first bus protection device and perform tracing analysis, share the first tracing result with the second bus protection device through the first data sharing channel, and call the first bidirectional misconduction relationship to determine whether there is misconduction with voltage sag.

[0097] The circuit protection module 50 is configured to, if not, perform a circuit protection operation based on the first tracing result through the first busbar protection device.

[0098] Furthermore, after establishing the first data sharing channel, the system according to the embodiment of the present application is further configured to perform the following steps:

[0099] The second busbar protection device is used to monitor the voltage sag behavior of the second busbar circuit and perform tracing analysis, and the second tracing result is shared with the first busbar protection device through the first data sharing channel. Based on the first bidirectional misconduction relationship, it is determined whether the voltage sag behavior is misconduction with voltage sag; if not, the second busbar protection device performs circuit protection operation based on the second tracing result.

[0100] Furthermore, the relationship analysis module 20 in the embodiment of the present application is further configured to perform the following steps:

[0101] Perform integrated circuit equivalent modeling on the first busbar protection device and the corresponding first busbar circuit, and the second busbar protection device and the corresponding second busbar circuit to generate an equivalent circuit model; based on the equivalent circuit model, perform protection simulations and voltage sag misconduction simulations on the first busbar circuit under multiple first voltage sag behaviors, determine the voltage sag conduction relationship that is misconducted to the second busbar circuit, and generate a first forward misconduction relationship; based on the equivalent circuit model, perform protection simulations and voltage sag misconduction simulations on the second busbar circuit under multiple second voltage sag behaviors, determine the voltage sag conduction relationship that is misconducted to the first busbar circuit, and generate a first reverse misconduction relationship; construct the first bidirectional misconduction relationship based on the first forward misconduction relationship and the first reverse misconduction relationship.

[0102] Furthermore, the relationship analysis module 20 in the embodiment of the present application is further configured to perform the following steps:

[0103] Collect the first device structural characteristics of the first busbar protection device and the first circuit structural characteristics of the corresponding first busbar circuit; collect the second device structural characteristics of the second busbar protection device and the second circuit structural characteristics of the corresponding second busbar circuit; collect the intermediate circuit connection characteristics between the first busbar circuit and the second busbar circuit; perform circuit equivalent modeling based on the first device structural characteristics, the first circuit structural characteristics, the second device structural characteristics, the second circuit structural characteristics and the intermediate circuit connection characteristics to generate the equivalent circuit model.

[0104] Furthermore, the first forward misconduction relationship includes the original voltage sag characteristics of the first bus circuit and the voltage sag characteristics that are misconducted to the second bus circuit; the first reverse misconduction relationship includes the original voltage sag characteristics of the second bus circuit and the voltage sag characteristics that are misconducted to the first bus circuit.

[0105] Furthermore, the misconductance determination module 40 in the embodiment of the present application is further configured to perform the following steps:

[0106] The voltage data of the first bus circuit is monitored by the voltage sensor in the first bus protection device to generate first voltage time series data; the voltage drop amplitude and duration are identified based on the first voltage time series data to generate a first real-time voltage sag feature; the first real-time voltage sag feature is input into the voltage sag tracing database for comparison to generate a first protection triggering decision; the first protection triggering decision and the first real-time voltage sag feature are used to generate the first tracing result.

[0107] Furthermore, the voltage sag tracing database includes multiple groups of historical voltage sag protection triggering data, wherein any group of historical voltage sag protection triggering data includes historical voltage sag characteristics, historical voltage sag factors and historical protection decisions.

[0108] Furthermore, the system described in the embodiment of the present application is further configured to perform the following steps before the first busbar protection device performs a circuit protection operation based on the first tracing result:

[0109] Collect the first other protection device located in the upstream circuit of the first busbar protection device within the preset power grid area; analyze the voltage sag misconduction relationship of the first other protection device that is transmitted in one direction to the first busbar protection device in the scenario where the protection logic is triggered by the first other protection device, and generate the misconduction relationship of other protection devices; construct a second data sharing channel between the first other protection device and the first busbar protection device; use the first busbar protection device to monitor the voltage sag behavior of the first busbar circuit and perform traceability analysis, share the first traceability result with the first other protection device through the second data sharing channel, call the misconduction relationship of the other protection device to determine whether there is misconduction of voltage sag, and determine whether to perform circuit protection operation based on the judgment result.

[0110] Through the above detailed description of the grid bus protection method combined with voltage sag tracing in this specification, those skilled in the art can clearly understand the grid bus protection system combined with voltage sag tracing in this embodiment. For the system disclosed in Example 2, since it corresponds to the method disclosed in Example 1 and has corresponding functional modules and beneficial effects, the relevant parts can be referred to the description of the method part.

[0111] In addition, based on the same inventive concept as the aforementioned embodiment 1, the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by the processor, the various processes of the above-mentioned grid bus protection method embodiment combined with voltage sag tracing are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0112] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power grid busbar protection method combined with voltage sag tracing is characterized in that: include: Collecting the first busbar protection device and the second busbar protection device having an upstream and downstream circuit relationship in a preset power grid area; performing a bidirectional voltage sag misconduction relationship analysis on the first busbar protection device and the second busbar protection device when voltage sag protection is triggered, to generate a first bidirectional misconduction relationship; establishing a first data sharing channel between the first busbar protection device and the second busbar protection device; The first busbar protection device monitors the voltage sag behavior of the first busbar circuit and performs a source tracing analysis, shares the first source tracing result with the second busbar protection device through the first data sharing channel, and calls the first bidirectional misconduction relationship to determine whether misconduction due to voltage sag exists; If not, the first busbar protection device performs circuit protection operation based on the first tracing result.

2. The power grid busbar protection method combined with voltage sag tracing according to claim 1 is characterized in that: After the first data sharing channel is established, the following steps are also included: The second busbar protection device is used to monitor the voltage sag behavior of the second busbar circuit and perform a source tracing analysis. The second source tracing result is shared with the first busbar protection device through the first data sharing channel. Based on the first bidirectional misconduction relationship, it is determined whether the voltage sag behavior is misconduction with voltage sag. If not, the second busbar protection device performs circuit protection operation based on the second tracing result.

3. The power grid busbar protection method combined with voltage sag tracing according to claim 1, characterized in that: Performing a bidirectional voltage sag misconduction relationship analysis on the first busbar protection device and the second busbar protection device when the voltage sag protection is triggered to generate a first bidirectional misconduction relationship includes: Performing integrated circuit equivalent modeling on the first busbar protection device and the corresponding first busbar circuit, the second busbar protection device and the corresponding second busbar circuit to generate an equivalent circuit model; Based on the equivalent circuit model, performing protection simulations and voltage sag misconduction simulations on the first bus circuit under a plurality of first voltage sag behaviors, determining a voltage sag misconduction relationship to the second bus circuit, and generating a first forward misconduction relationship; Based on the equivalent circuit model, performing protection simulations and voltage sag misconduction simulations on the second bus circuit under multiple second voltage sag behaviors, determining a voltage sag misconduction relationship to the first bus circuit, and generating a first reverse misconduction relationship; The first bidirectional misconduction relationship is constructed using the first forward misconduction relationship and the first reverse misconduction relationship.

4. The power grid busbar protection method combined with voltage sag tracing according to claim 3 is characterized in that: Performing integrated circuit equivalent modeling on the first busbar protection device, the first busbar circuit, the second busbar protection device, and the second busbar circuit to generate an equivalent circuit model includes: collecting a first device structural feature of the first busbar protection device and a first circuit structural feature of the corresponding first busbar circuit; collecting a second device structural feature of the second busbar protection device and a second circuit structural feature of the corresponding second busbar circuit; collecting connection characteristics of an intermediate circuit between the first bus circuit and the second bus circuit; Circuit equivalent modeling is performed based on the first device structure feature, the first circuit structure feature, the second device structure feature, the second circuit structure feature, and the intermediate circuit connection feature to generate the equivalent circuit model.

5. The power grid busbar protection method combined with voltage sag tracing according to claim 3 is characterized in that: The first forward misconduction relationship includes the original voltage sag characteristics of the first bus circuit and the voltage sag characteristics mistakenly conducted to the second bus circuit; the first reverse misconduction relationship includes the original voltage sag characteristics of the second bus circuit and the voltage sag characteristics mistakenly conducted to the first bus circuit.

6. The power grid busbar protection method combined with voltage sag tracing according to claim 1, characterized in that: The first busbar protection device is used to monitor the voltage sag behavior of the first busbar circuit and perform source tracing analysis, including: Monitoring the voltage data of the first bus circuit by a voltage sensor in the first bus protection device to generate first voltage time series data; Identifying a voltage drop amplitude and duration based on the first voltage time series data to generate a first real-time voltage sag feature; Inputting the first real-time voltage sag feature into a voltage sag tracing database for comparison to generate a first protection triggering decision; The first tracing result is generated based on the first protection triggering decision and the first real-time voltage sag feature.

7. The power grid busbar protection method combined with voltage sag tracing according to claim 6, characterized in that: The voltage sag tracing database includes multiple groups of historical voltage sag protection triggering data, wherein any group of historical voltage sag protection triggering data includes historical voltage sag characteristics, historical voltage sag factors and historical protection decisions.

8. The power grid busbar protection method combined with voltage sag tracing according to claim 1, characterized in that: Before the first busbar protection device performs a circuit protection operation based on the first tracing result, the method further includes: collecting data from a first other protection device located in an upstream circuit of the first busbar protection device within the preset power grid area; Analyze the voltage sag misconduction relationship of the first busbar protection device in a scenario where the protection logic of the first other protection device is triggered, and generate misconduction relationships of other protection devices; Establishing a second data sharing channel between the first other protection device and the first bus protection device; Use the first busbar protection device to monitor the voltage sag behavior of the first busbar circuit and perform tracing analysis, share the first tracing result with the first other protection device through the second data sharing channel, call the error conduction relationship of the other protection device to determine whether there is error conduction of voltage sag, and determine whether to perform circuit protection operation based on the judgment result.

9. The power grid busbar protection system combined with voltage sag tracing is characterized by: The system is used to execute the power grid bus protection method combined with voltage sag tracing according to any one of claims 1 to 8, comprising: A collection module, configured to collect information about a first busbar protection device and a second busbar protection device having an upstream and downstream circuit relationship in a preset power grid area; a relationship analysis module, configured to perform a bidirectional voltage sag misconduction relationship analysis on the first busbar protection device and the second busbar protection device under voltage sag protection triggering, and generate a first bidirectional misconduction relationship; a data sharing module, configured to establish a first data sharing channel between the first busbar protection device and the second busbar protection device; a misconduction judgment module, configured to monitor the voltage sag behavior of the first bus circuit using the first bus protection device and perform a source tracing analysis, share the first source tracing result with the second bus protection device via the first data sharing channel, and invoke the first bidirectional misconduction relationship to determine whether misconduction due to a voltage sag exists; A circuit protection module is used to: if not, the first busbar protection device performs a circuit protection operation based on the first tracing result.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the power grid bus protection method combined with voltage sag tracing according to any one of claims 1 to 8 are implemented.

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