A method, system, device and medium for locating a voltage sag source

Abstract

The present invention relates to the technical field of power systems, and discloses a method, system, device, and medium for locating a voltage sag source. The method obtains fault data and voltage sag data, and subdivides the fault data into internal fault data and external fault data, and sorts these two types of data and the voltage sag data in chronological order to obtain fault time series data and voltage sag time series data. The fault time series data and the voltage sag time series data are matched with the time of occurrence of each fault point and the sag time of each sag data point to obtain a preliminary fault sag matching result. The repeated sag data points in the matching result are further extracted, and the data points are re-divided separately according to their sag duration. The method can accurately and quickly locate the sag source without relying on high-precision monitoring data, effectively improving the accuracy of locating the sag source.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to a method, system, equipment and medium for locating a voltage sag source. Background Art

[0002] In recent years, the rapid development of power systems and the widespread use of electrical equipment have led to increasing attention to voltage sags. Although short-lived, voltage sags can have profound impacts across multiple industries and societies, particularly in critical sectors such as industry, commerce, and healthcare. Their consequences cannot be ignored.

[0003] In industrial production, many technologically sensitive equipment has extremely stringent voltage stability requirements. Voltage sags can easily cause equipment malfunctions, downtime, or even damage. This not only imposes high equipment maintenance and replacement costs on companies, but can also disrupt production lines, reduce overall production efficiency, increase scrap rates, and increase quality management costs. More seriously, production interruptions can lead to delivery delays, causing direct financial losses and potentially damaging market reputation. While measures such as installing uninterruptible power supplies, voltage regulators, or optimizing intranet design can mitigate the impact of voltage sags to some extent, these approaches often have significant technical limitations or require prohibitive initial investments, making them unaffordable for many small and medium-sized enterprises. Furthermore, voltage sags often involve multiple parties, making clear who is responsible for power generation, transmission, and distribution a key management task to ensure accurate identification of the source of the sag.

[0004] Traditional methods for locating voltage sag sources typically rely on one or two parameters at a monitoring point to determine the upstream or downstream location of the sag source. However, the limitations of these methods are that they can only provide the approximate direction of the sag source relative to the monitoring point, making it difficult to further clarify the specific location of the sag source within the entire power grid and to refine the impact of different line faults on users. While sag source locating methods based on comprehensive criteria and intelligent algorithms offer high positioning accuracy and can precisely determine the location of the fault point, their calculation process is complex, the algorithm engineering is difficult, and some criteria contain fuzzy areas that affect the accuracy of source tracing to a certain extent.

[0005] In summary, existing methods for locating voltage sag sources are generally categorized into upstream and downstream positioning and precise positioning. These methods primarily rely on simulation analysis or measured data, which has improved positioning accuracy to a certain extent, but still has significant limitations. Simulation-based methods, due to inadequate handling of complex factors in actual operating conditions (such as changes in operating mode), suffer from biases, making them difficult to directly apply in real-world scenarios. On the other hand, methods based on measured data rely on large amounts of high-quality measured data to train the model, but the quality of actual monitoring data is difficult to meet training requirements, making it impossible to accurately locate voltage sag sources in real-world applications. Summary of the Invention

[0006] In view of this, in order to solve the above-mentioned technical problems, the present invention provides a method, system, device and medium for locating a voltage sag source.

[0007] A first aspect of the present invention provides a method for locating a voltage sag source, the method comprising:

[0008] Acquire fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data;

[0009] The fault data and the voltage sag data are sorted according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes multiple fault points and the fault occurrence time of the fault points, and the voltage sag time series data includes multiple sag data points and the sag occurrence time and sag duration of the sag data points;

[0010] According to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, timing error matching is performed on the fault time series data and the voltage sag time series data to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set;

[0011] Determine a plurality of repeated sag data points according to the internal fault sag matching set and the external fault sag matching set; the repeated sag data points are sag data points that exist in both the internal fault sag matching set and the external fault sag matching set;

[0012] According to the dip duration of each of the repeated dip data points, the repeated dip data points are separately divided into the internal fault dip matching set and the external fault dip matching set.

[0013] Preferably, after obtaining the fault data and voltage sag data monitored by a plurality of preset monitoring nodes in the target substation, the method further includes:

[0014] The fault data and the voltage sag data are pre-processed and their time formats are unified.

[0015] Preferably, the method further comprises:

[0016] According to the location of the target substation where the fault data is located and the bus voltage level thereof, the fault data is identified as the internal fault data or the external fault data.

[0017] Preferably, the method further comprises:

[0018] For each of the monitoring nodes, determining whether a time difference between the voltage sag occurrence times of two voltage sag data points in the voltage sag time series data is less than a preset first time difference threshold;

[0019] When it is determined that the time difference between the sag occurrence times of two sag data points in the voltage sag time series data is less than the preset first time difference threshold, the two sag data points are merged, and the merged sag data point is updated based on the minimum residual voltage of the two sag data points, the sag occurrence time corresponding to the minimum residual voltage, and the sag duration.

[0020] Preferably, performing timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point to obtain a fault sag matching set includes:

[0021] Starting from the first fault point in the fault time series data, traversing, when a sag data point is found in the voltage sag time series data whose sag occurrence time satisfies a time difference from the fault occurrence time of the fault point that is less than a preset second time difference threshold, taking the sag data point as the sag data point that successfully matches the fault point;

[0022] Adding the fault point and the sag data point that successfully matches the fault point to the fault sag matching set, removing the sag data point that successfully matches the fault point from the voltage sag time series data, updating the voltage sag time series data, and updating the fault point plus 1;

[0023] Based on the updated voltage sag time series data and the fault point, the traversal starting from the first fault point in the fault time series data is re-executed. When a voltage sag data point is found whose sag occurrence time satisfies a time difference between the first voltage sag data point in the voltage sag time series data and the fault occurrence time of the fault point and is less than a preset second time difference threshold, the sag data point is used as the sag data point that successfully matches the fault point. This process continues until all fault points in the fault time series data are traversed, thereby obtaining the fault sag matching set.

[0024] Preferably, the re-dividing the repeated dip data points into the internal fault dip matching set and the external fault dip matching set according to the dip duration of each repeated dip data point comprises:

[0025] For each of the repeated sag data points, determining whether the sag duration of the repeated sag data point is less than a preset relay protection action boundary time;

[0026] When it is determined that the sag duration of the repeated sag data point is less than the preset relay protection action boundary time, the repeated sag data point is separately classified into the external fault sag matching set;

[0027] When it is determined that the sag duration of the repeated sag data point is not less than the preset relay protection action boundary time, the repeated sag data point is separately divided into the internal fault sag matching set.

[0028] Preferably, the method further comprises:

[0029] Arrange the matching data groups in the fault dip matching set in ascending order according to the time difference; wherein the matching data group includes the fault point and the dip data point matching the fault point;

[0030] Determining the first quartile and the third quartile of the time difference according to the time difference of each matching data group;

[0031] Determining the interquartile range of the time difference according to the first quartile and the third quartile;

[0032] Determining an expected time difference range threshold according to the interquartile range, the first quartile, and the third quartile;

[0033] For each of the matching data groups, determining whether the time difference of the matching data group meets the expected time difference range threshold;

[0034] When it is determined that the time difference of the matching data group does not meet the expected time difference range threshold, the matching data group is determined to be an incorrect match, and the hysteresis data in the matching data group is identified as a fault point or a sag data point, the hysteresis data is removed from the fault time series data or the voltage sag time series data, and the fault time series data or the voltage sag time series data is updated;

[0035] Based on the updated fault time series data or voltage sag time series data, the step of re-performing the timing error matching of the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point is performed to obtain a fault sag matching set, until the time difference between the matching data groups meets the expected time difference range threshold.

[0036] In a second aspect, the present invention provides a system for locating a voltage sag source, the system comprising:

[0037] A data acquisition module is used to acquire fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data;

[0038] a data sorting module, configured to sort the fault data and the voltage sag data according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes a plurality of fault points and the fault occurrence time of the fault points; the voltage sag time series data includes a plurality of sag data points and the sag occurrence time and sag duration of the sag data points;

[0039] a data matching module, configured to perform timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set;

[0040] a duplicate data screening module, configured to determine a plurality of duplicate dip data points according to the internal fault dip matching set and the external fault dip matching set; the duplicate dip data points are dip data points that exist in both the internal fault dip matching set and the external fault dip matching set;

[0041] The data updating module is configured to re-divide the repeated dip data points into the internal fault dip matching set and the external fault dip matching set according to the dip duration of each repeated dip data point.

[0042] In a third aspect, the present invention provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the voltage sag source locating method as described in the first aspect.

[0043] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of the method for locating a voltage sag source as described in the first aspect.

[0044] As can be seen from the above technical solutions, the present invention obtains fault data and voltage sag data, and subdivides the fault data into internal fault data and external fault data, and sorts these two types of data and the voltage sag data in chronological order to obtain fault time series data and voltage sag time series data. The fault time series data and voltage sag time series data are matched for timing errors using the occurrence time of each fault point and the sag time of each sag data point, thereby obtaining a preliminary fault sag matching result. Repeated sag data points in the matching results are further extracted and reclassified based on the sag duration of these data points. This method can accurately and quickly locate the sag source without relying on high-precision monitoring data, effectively improving the accuracy of locating the sag source. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 A diagram illustrating an application environment of a method for locating a voltage sag source provided by an embodiment of the present invention;

[0047] Figure 2 A flow chart of a method for locating a voltage sag source provided by an embodiment of the present invention;

[0048] Figure 3 A schematic structural diagram of a voltage sag source locating system provided by an embodiment of the present invention;

[0049] Figure 4 A schematic structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0051] The voltage sag source location method provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the terminal 101 communicates with the server 102 through the network. The data storage system can store the data that the server 102 needs to process. The data storage system can be integrated on the server 102, or it can be placed on the cloud or other network servers. The terminal 101 or the server 102 obtains the fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data; the fault data and the voltage sag data are sorted according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes multiple fault points and the fault occurrence time of the fault point, and the voltage sag time series data includes multiple sag data points and the sag occurrence time and sag duration of the sag data point; according to the fault occurrence time of each fault point and the sag duration of each sag data point The fault time series data and the voltage sag time series data are matched with each other to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set; based on the internal fault sag matching set and the external fault sag matching set, multiple repeated sag data points are determined; the repeated sag data points are sag data points that exist in both the internal fault sag matching set and the external fault sag matching set; based on the sag duration of each repeated sag data point, the repeated sag data points are separately divided into the internal fault sag matching set and the external fault sag matching set.

[0052] The terminal 101 may be, but is not limited to, various personal computers, laptops, smart phones, tablet computers, and the like.

[0053] The server 102 may be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0054] like Figure 2 As shown, the embodiment of the present application provides a method for locating a voltage sag source, which is applied to Figure 1 The terminal 101 or the server 102 in the embodiment is used as an example to illustrate the method, which includes the following steps S1 to S5.

[0055] Step S1: Acquire fault data and voltage sag data monitored by a plurality of preset monitoring nodes in a target substation; wherein the fault data includes internal fault data and external fault data.

[0056] Internal fault data refers to fault data that occurs on equipment within the target substation. This type of fault is usually related to factors such as equipment failure, operational errors, or improper maintenance within the substation. External fault data refers to fault data caused by factors outside the target substation.

[0057] The fault data is identified as internal fault data or external fault data according to the location of the target substation where the fault data is located and the voltage level of the busbar to which it belongs.

[0058] For example, fault data is divided into internal faults and external faults based on the voltage sag propagation characteristics. In a 220kV substation, all faults under the 10kV bus where the monitoring node is located are internal fault data, and the 110kV and 220kV fault data of the station and the 220kV and above faults outside the station are external fault data. The monitoring nodes are all installed at the 10kV feeder.

[0059] To facilitate subsequent processing, preprocess fault data and voltage sag data and unify the time format, such as minutes. Preprocessing includes steps such as filtering out abnormal data and cleaning data to ensure data accuracy and reliability. Data cleaning steps may include, but are not limited to, removing missing values, addressing outliers, and smoothing data fluctuations to improve data accuracy and completeness.

[0060] Step S2: sort the fault data and voltage sag data by time to obtain fault time series data and voltage sag time series data; the fault time series data includes multiple fault points and the fault occurrence time of the fault points, and the voltage sag time series data includes multiple sag data points and the sag occurrence time and sag duration of the sag data points.

[0061] Among them, the fault data and voltage sag data can be sorted in ascending order according to time, and the voltage sag data is set to S:

[0062]

[0063] in, Represents the voltage sag dataset of monitoring node i, i=1,2,…,n, and n is the total number of monitoring points.

[0064] Arrange the voltage sag data of each monitoring point in ascending order according to the time of occurrence of the sag:

[0065]

[0066] in, represents the j-th sag data point at monitoring point i, j=1,2,…,m, and m is the total number of sag data points at this monitoring point.

[0067] Each sag data point contains the following features:

[0068]

[0069] in, is the residual voltage of the j-th sag data point at monitoring point i, is the duration of the sag data point, is the sag occurrence time of the sag data point.

[0070] Fault data is divided into internal fault data and external fault data. Let the internal fault set be F in , the external fault set is F out :

[0071]

[0072]

[0073] in, To monitor all internal faults under the 10kV bus where node i is located, is all external faults under monitoring node i.

[0074] Arrange the fault data in ascending order by fault occurrence time:

[0075]

[0076]

[0077] in, is the jth internal fault under the 10kV bus where the monitoring point i is located, For the jth external fault, each data point / Contains the following features:

[0078]

[0079]

[0080] in, is the time when the fault occurred, The voltage level to which the fault belongs.

[0081] Step S3: performing timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set.

[0082] Wherein, a time comparison is performed between each fault point in the fault time series data and each voltage sag data point in the voltage sag time series data to determine the time correlation between them.

[0083] If the fault occurrence time of a certain fault point is close to the sag occurrence time of a certain sag data point and is within a preset time error range, the fault point is paired with the sag data point to form a matching data pair.

[0084] All matching data pairs are divided into internal fault and external fault types, forming internal fault sag matching sets and external fault sag matching sets, respectively. The internal fault sag matching set includes sag data points associated with internal fault data, while the external fault sag matching set includes sag data points associated with external fault data. By matching the timing errors of the fault time series data and the voltage sag time series data, the voltage sag events associated with the fault can be accurately identified.

[0085] Step S4: determining a plurality of repeated dip data points according to the internal fault dip matching set and the external fault dip matching set; the repeated dip data points are dip data points that exist in both the internal fault dip matching set and the external fault dip matching set.

[0086] By comparing the internal fault sag matching set with the external fault sag matching set, we identify those sag data points that appear simultaneously in both matching sets. These data points are referred to as duplicate sag data points. The presence of duplicate sag data points may indicate that these sag events are caused by complex fault conditions, associated with both internal and external faults. Alternatively, these duplicate data points may be due to errors in data recording or processing. Therefore, in-depth analysis of duplicate sag data points helps to more accurately locate the source of the voltage sag.

[0087] Step S5: Re-classify the repeated dip data points into an internal fault dip matching set and an external fault dip matching set according to the dip duration of each repeated dip data point.

[0088] The sag duration of repeated sag data points is further analyzed and compared with the duration characteristics of internal and external faults. If the sag duration of a repeated sag data point more closely matches the duration characteristics of an internal fault, it is reclassified into the internal fault sag matching set; if the sag duration of a repeated sag data point more closely matches the duration characteristics of an external fault, it is reclassified into the external fault sag matching set. This step helps to more accurately distinguish whether a voltage sag event is caused by an internal or external fault, thereby improving the accuracy of locating the voltage sag source. By reclassifying the repeated sag data points, the possible sources of the voltage sag can be further narrowed down.

[0089] It should be noted that the embodiment of the present application obtains fault data and voltage sag data, and subdivides the fault data into internal fault data and external fault data, and sorts these two types of data and the voltage sag data in chronological order to obtain fault time series data and voltage sag time series data. The occurrence time of each fault point and the sag time of each sag data point are used to match the fault time series data and the voltage sag time series data, thereby obtaining a preliminary fault sag matching result. The repeated sag data points in the matching results are further extracted and re-divided according to the sag duration of these data points. This method can accurately and quickly locate the sag source without relying on high-precision monitoring data, effectively improving the accuracy of locating the sag source.

[0090] To avoid repeated calculations caused by the secondary sag due to reclosing, which affects the algorithm performance, in some embodiments, the sag data of the same monitoring node i are merged. Specifically, the method further includes:

[0091] Step S21 : for each monitoring node, determining whether a time difference between two voltage sag data points in the voltage sag time series data is less than a preset first time difference threshold.

[0092] Step S22: When it is determined that the time difference between the sag occurrence times of two sag data points in the voltage sag time series data is less than a preset first time difference threshold, the two sag data points are merged, and the merged sag data point is updated based on the minimum residual voltage of the two sag data points, the sag occurrence time corresponding to the minimum residual voltage, and the sag duration.

[0093] When it is determined that the time difference between the voltage sag occurrence times of two voltage sag data points in the voltage sag time series data is not less than a preset first time difference threshold, the two voltage sag data points are no longer merged.

[0094] For example, the voltage sag data of the same monitoring node i are merged for one minute, starting from the first sag data point of the monitoring node i, if there is a next sag data point that satisfies , we get:

[0095]

[0096]

[0097] in, 、 are the sag occurrence times of the two sag data points, T ih is the duration of the sag corresponding to the minimum residual voltage of the two sags, are the residual voltages of the two sag data points, is the residual voltage after merging, is the combined sag duration.

[0098] From S i The latter of the two temporary dip data is filtered out, and so on until there is no temporary dip data that can be merged two by two.

[0099] In some embodiments, according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, timing error matching is performed on the fault time series data and the voltage sag time series data to obtain a fault sag matching set, including:

[0100] Step S301: Start traversing from the first fault point in the fault time series data, and when a voltage sag data point is found whose sag occurrence time satisfies the time difference between the first sag data point in the voltage sag time series data and the fault occurrence time of the fault point and is less than a preset second time difference threshold, the sag data point is regarded as a sag data point that successfully matches the fault point.

[0101] Step S302: Add the fault point and the sag data point that successfully matches the fault point to the fault sag matching set, remove the sag data point that successfully matches the fault point from the voltage sag time series data, update the voltage sag time series data, and update the fault point plus 1.

[0102] When no sag data point in the voltage sag time series data is found whose sag occurrence time satisfies the time difference between the sag occurrence time of the fault point and ...

[0103] Step S303: Based on the updated voltage sag time series data and the fault point, traversal is re-executed starting from the first fault point in the fault time series data. When a voltage sag data point is found whose sag occurrence time satisfies the time difference between the first sag data point in the voltage sag time series data and the fault occurrence time of the fault point and is less than a preset second time difference threshold, the sag data point is regarded as a successfully matched sag data point. This process continues until all fault points in the fault time series data are traversed, thereby obtaining a fault sag matching set.

[0104] For example, from the internal fault timing data F in,1 Starting from the first fault, traverse the voltage sag time series data. When the first sag is found that meets the time difference of less than T (adaptive according to actual situation, such as 30 minutes) from the fault occurrence time, the initial matching is successful. The matched fault and sag will not participate in subsequent matching;

[0105] If no dip that meets the time difference requirement is found, the fault does not match the dip, and so on until all faults in Fin are matched to obtain the internal fault set matching result. ( , ,…).

[0106] External fault timing data F out The matching process of the internal fault timing data is similar to that of the external fault timing data F out Starting from the first fault, traverse the voltage sag timing data. When the first sag that meets the time difference of less than T with the fault occurrence time is found, the initial matching is successful, and the matched fault and sag do not participate in the subsequent matching; if no sag that meets the time difference requirement is found, the fault is not matched with the sag, and so on until the external fault timing data F out All fault matching is completed to obtain the external fault set matching results ( , ,…).

[0107] In some embodiments, the repeated dip data points are re-classified into an internal fault dip matching set and an external fault dip matching set according to the dip duration of each repeated dip data point, including:

[0108] Step S501: for each repeated sag data point, determine whether the sag duration of the repeated sag data point is less than a preset relay protection action boundary time;

[0109] Because internal and external faults occur at different bus voltage levels, the time it takes for relay protection to clear the fault also differs. High-voltage levels, which carry large amounts of power, require rapid fault clearance. When a fault occurs, relay protection devices immediately operate without determining whether to override the fault level, ensuring grid stability. Low-voltage levels (10kV and below), on the other hand, are located at the end of the distribution network, where faults have a smaller impact range. This allows for longer operating times, prioritizing lower-level protection (such as user-side circuit breakers) to avoid over-tripping.

[0110] Step S502: when it is determined that the sag duration of the repeated sag data point is less than the preset relay protection action boundary time, the repeated sag data point is separately classified into the external fault sag matching set;

[0111] Step S503: when it is determined that the sag duration of the repeated sag data point is not less than the preset relay protection action boundary time, the repeated sag data point is separately classified into the internal fault sag matching set.

[0112] Among them, the relay protection action demarcation time is determined based on the action time of the high and low voltage level relay protection devices. For example, the demarcation value of the temporary sag duration in the high and low voltage level relay protection devices is usually 80~100ms (selected according to actual conditions), that is, the relay protection action demarcation time is 80~100ms. According to the demarcation value, the repeated part of the internal and external matching results is used to judge the causes of the internal and external faults. If the duration of the voltage sag is less than the relay protection action demarcation time, it is classified into the external fault temporary sag matching set; otherwise, it is classified into the internal fault temporary sag matching set.

[0113] In some embodiments, considering that the timing errors of power quality monitoring devices at different monitoring points are different, while the timing errors at the same monitoring point are relatively stable, the difference between the fault occurrence time and the sag occurrence time should fluctuate around a fixed value. Therefore, the interquartile range (IQR) method is used to filter abnormal data based on the preliminary matching results of the monitoring points. Therefore, this method also includes:

[0114] Step S601: Arrange the matching data groups in the fault dip matching set in ascending order according to the time difference; wherein the matching data group includes the fault point and the dip data points that match the fault point;

[0115] Among them, select the interval of the upper and lower limits of the time difference , and calculate the time difference between the fault occurrence time and the voltage sag occurrence time for each matching data group for subsequent analysis. The formula is as follows:

[0116]

[0117] in, represents the difference between the fault and sag occurrence times in the lth matching result, is the fault occurrence time in the lth matching result, is the time when the temporary dip occurs in the lth matching result.

[0118] Step S602: Determine the first quartile and the third quartile of the time difference according to the time difference of each matching data group.

[0119] Step S603: Determine the interquartile range of the time difference based on the first quartile and the third quartile.

[0120] The IQR method is a statistic used to describe the degree of dispersion of data distribution. By calculating the IQR, the range of outliers in the data can be determined. The interquartile range (IQR) of the time difference is calculated. The IQR is equal to the difference between the third quartile and the first quartile, that is:

[0121]

[0122] Where IQR is the interquartile range, Q1 is the first quartile, and Q3 is the third quartile.

[0123] Step S604: Determine the expected time difference range threshold according to the interquartile range, the first quartile, and the third quartile.

[0124] The difference between the first quartile and 1.5 times the IQR to the sum of the third quartile and 1.5 times the IQR is used as the expected time difference range threshold.

[0125] Step S605: For each matching data group, determine whether the time difference of the matching data group meets the expected time difference range threshold.

[0126] In this method, matching data groups with a time difference greater than the sum of the third quartile and 1.5 times the IQR or less than the difference between the first quartile and 1.5 times the IQR are regarded as abnormal data and eliminated from the fault sag matching set, which helps to further improve the accuracy of voltage sag source location and reduce mismatching caused by timing errors.

[0127] Step S606: When it is determined that the time difference of the matching data group does not meet the expected time difference range threshold, the matching data group is determined to be a mismatch, and the lagging data in the matching data group is identified as a fault point or a sag data point. The lagging data is removed from the fault time series data or the voltage sag time series data, and the fault time series data or the voltage sag time series data is updated.

[0128] For example, for the matching data group of the same monitoring node i, and The result is initially considered to be the result of an incorrect match. If the matching result contains a temporary drop hysteresis fault, then in，i / F out Eliminate the fault point and retain the temporary sag data point; otherwise, i The temporary drop data point is eliminated and the fault point is retained.

[0129] Step S607: Based on the updated fault time series data or voltage sag time series data, re-execute the timing error matching of the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point to obtain a fault sag matching set, until the time difference of the matching data groups meets the expected time difference range threshold.

[0130] Wherein, step S3 is repeated until the matching result is All satisfied .like All satisfied , then directly output the fault dip matching set.

[0131] It can be understood that by performing interquartile range analysis on the time difference, abnormal matching data caused by the timing error of the monitoring device can be effectively eliminated, thereby improving the accuracy of locating the voltage sag source.

[0132] Based on the same inventive concept, an embodiment of the present application further provides a voltage sag source locating system for implementing the above-mentioned voltage sag source locating method.

[0133] The implementation solution provided by the system to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations of one or more voltage sag source locating system embodiments provided below can refer to the limitations of the voltage sag source locating method above and will not be repeated here.

[0134] like Figure 3 As shown, an embodiment of the present application provides a voltage sag source locating system, the system comprising:

[0135] The data acquisition module 100 is used to acquire fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data;

[0136] The data sorting module 200 is used to sort the fault data and the voltage sag data according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes multiple fault points and the fault occurrence time of the fault points, and the voltage sag time series data includes multiple sag data points and the sag occurrence time and sag duration of the sag data points;

[0137] The data matching module 300 is used to perform timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set;

[0138] The duplicate data screening module 400 is used to determine multiple duplicate dip data points according to the internal fault dip matching set and the external fault dip matching set; the duplicate dip data points are dip data points that exist in both the internal fault dip matching set and the external fault dip matching set;

[0139] The data updating module 500 is configured to re-divide the repeated dip data points into an internal fault dip matching set and an external fault dip matching set according to the dip duration of each repeated dip data point.

[0140] In some embodiments, the system further comprises:

[0141] The preprocessing module is used to preprocess the fault data and voltage sag data and unify the time format.

[0142] In some embodiments, the system further comprises:

[0143] The fault identification module is used to identify whether the fault data is internal fault data or external fault data according to the location of the target substation where the fault data is located and the voltage level of the busbar to which it belongs.

[0144] In some embodiments, the system further comprises:

[0145] A time difference judgment module is used to judge, for each monitoring node, whether the time difference between the sag occurrence times of two sag data points in the voltage sag time series data is less than a preset first time difference threshold;

[0146] The data merging module is configured to merge the two sag data points when it is determined that the time difference between the sag occurrence times of two sag data points in the voltage sag time series data is less than a preset first time difference threshold, and update the merged sag data point based on the minimum residual voltage of the two sag data points and the sag occurrence time and sag duration corresponding to the minimum residual voltage.

[0147] In some embodiments, the data matching module 300 includes:

[0148] a data search module configured to traverse from the first fault point in the fault time series data, and when a sag data point is found whose sag occurrence time satisfies the time difference between the first sag data point in the voltage sag time series data and the fault occurrence time of the fault point and is less than a preset second time difference threshold, the sag data point is regarded as a sag data point that successfully matches the fault point;

[0149] A data update module is used to add the fault point and the sag data point that successfully matches the fault point to the fault sag matching set, and remove the sag data point that successfully matches the fault point from the voltage sag time series data, update the voltage sag time series data, and update the fault point plus 1;

[0150] The data traversal module is configured to re-execute the traversal starting from the first fault point in the fault time series data based on the updated voltage sag time series data and the fault point. When a sag data point is found whose sag occurrence time satisfies the time difference between the sag occurrence time of the first sag data point in the voltage sag time series data and the fault point and is less than a preset second time difference threshold, the sag data point is regarded as a sag data point that successfully matches the fault point. This process continues until all fault points in the fault time series data are traversed, thereby obtaining a fault sag matching set.

[0151] In some embodiments, the data update module 500 includes:

[0152] The duration judgment module is used to judge whether the sag duration of each sag repetition data point is less than the preset relay protection action boundary time;

[0153] The first division module is used to classify the repeated sag data points into the external fault sag matching set separately when it is determined that the sag duration of the repeated sag data points is less than the preset relay protection action boundary time;

[0154] The second division module is used to divide the repeated sag data points into the internal fault sag matching set separately when it is determined that the sag duration of the repeated sag data points is not less than the preset relay protection action boundary time.

[0155] In some embodiments, the system further comprises:

[0156] A data sorting module is used to sort the matching data groups in the fault dip matching set in ascending order according to the time difference; wherein the matching data group includes the fault point and the dip data point that matches the fault point;

[0157] A quantile determination module is used to determine the first quartile and the third quartile of the time difference according to the time difference of each matching data group;

[0158] An interquartile range determination module, used to determine the interquartile range of the time difference based on the first quartile and the third quartile;

[0159] A threshold determination module is used to determine an expected time difference range threshold based on the interquartile range, the first quartile and the third quartile;

[0160] A time difference comparison module is used to determine, for each matching data group, whether the time difference of the matching data group meets the expected time difference range threshold;

[0161] A data filtering module is configured to determine that the matching data group is an incorrect match when the time difference of the matching data group does not meet the expected time difference range threshold, identify the lagging data in the matching data group as a fault point or a sag data point, remove the lagging data from the fault time series data or the voltage sag time series data, and update the fault time series data or the voltage sag time series data;

[0162] The data matching execution module is used to re-execute the time error matching of the fault time series data and the voltage sag time series data based on the fault occurrence time of each fault point and the sag occurrence time of each sag data point based on the updated fault time series data or voltage sag time series data, to obtain a fault sag matching set, until the time difference of the matching data groups meets the expected time difference range threshold.

[0163] like Figure 4 As shown, an embodiment of the present application provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 performs the steps of the voltage sag source locating method in the above embodiment.

[0164] An embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the steps of the method for locating a voltage sag source in the above embodiment are implemented.

[0165] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, electronic devices, and computer storage media can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0166] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0167] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0168] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0169] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0170] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0171] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for executing all or part of the steps of the method described in each embodiment of the present invention via a computer device (which can be a personal computer, server, or network device, etc.). The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0172] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for locating a voltage sag source, characterized in that: The method comprises: Acquire fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data; The fault data and the voltage sag data are sorted according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes multiple fault points and the fault occurrence time of the fault points, and the voltage sag time series data includes multiple sag data points and the sag occurrence time and sag duration of the sag data points; According to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, timing error matching is performed on the fault time series data and the voltage sag time series data to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set; Determine a plurality of repeated sag data points according to the internal fault sag matching set and the external fault sag matching set; the repeated sag data points are sag data points that exist in both the internal fault sag matching set and the external fault sag matching set; According to the dip duration of each of the repeated dip data points, the repeated dip data points are separately divided into the internal fault dip matching set and the external fault dip matching set.

2. The method for locating a voltage sag source according to claim 1, wherein: After obtaining the fault data and voltage sag data monitored by a plurality of preset monitoring nodes in the target substation, the method further includes: The fault data and the voltage sag data are pre-processed and their time formats are unified.

3. The method for locating a voltage sag source according to claim 1, wherein: Also includes: According to the location of the target substation where the fault data is located and the bus voltage level thereof, the fault data is identified as the internal fault data or the external fault data.

4. The method for locating a voltage sag source according to any one of claims 1 to 3, wherein: Also includes: For each of the monitoring nodes, determining whether a time difference between the voltage sag occurrence times of two voltage sag data points in the voltage sag time series data is less than a preset first time difference threshold; When it is determined that the time difference between the sag occurrence times of two sag data points in the voltage sag time series data is less than the preset first time difference threshold, the two sag data points are merged, and the merged sag data point is updated based on the minimum residual voltage of the two sag data points, the sag occurrence time corresponding to the minimum residual voltage, and the sag duration.

5. The method for locating a voltage sag source according to any one of claims 1 to 3, characterized in that: The performing timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point to obtain a fault sag matching set includes: Starting from the first fault point in the fault time series data, traversing, when a sag data point is found in the voltage sag time series data whose sag occurrence time satisfies a time difference from the fault occurrence time of the fault point that is less than a preset second time difference threshold, taking the sag data point as the sag data point that successfully matches the fault point; Adding the fault point and the sag data point that successfully matches the fault point to the fault sag matching set, removing the sag data point that successfully matches the fault point from the voltage sag time series data, updating the voltage sag time series data, and updating the fault point plus 1; Based on the updated voltage sag time series data and the fault point, the traversal starting from the first fault point in the fault time series data is re-executed. When a voltage sag data point is found whose sag occurrence time satisfies a time difference between the first voltage sag data point in the voltage sag time series data and the fault occurrence time of the fault point and is less than a preset second time difference threshold, the sag data point is used as the sag data point that successfully matches the fault point. This process continues until all fault points in the fault time series data are traversed, thereby obtaining the fault sag matching set.

6. The method for locating a voltage sag source according to any one of claims 1 to 3, characterized in that: The re-dividing the repeated dip data points into the internal fault dip matching set and the external fault dip matching set according to the dip duration of each repeated dip data point comprises: For each of the repeated sag data points, determining whether the sag duration of the repeated sag data point is less than a preset relay protection action boundary time; When it is determined that the sag duration of the repeated sag data point is less than the preset relay protection action boundary time, the repeated sag data point is separately classified into the external fault sag matching set; When it is determined that the sag duration of the repeated sag data point is not less than the preset relay protection action boundary time, the repeated sag data point is separately divided into the internal fault sag matching set.

7. The method for locating a voltage sag source according to any one of claims 1 to 3, characterized in that: Also includes: Calculating the time difference between the fault occurrence time and the voltage sag occurrence time for each matching data group, and arranging the matching data groups in the fault sag matching set in ascending order according to the time difference; wherein the matching data group includes the fault point and the sag data point that matches the fault point; Determining the first quartile and the third quartile of the time difference according to the time difference of each matching data group; Determining the interquartile range of the time difference according to the first quartile and the third quartile; Determining an expected time difference range threshold according to the interquartile range, the first quartile, and the third quartile; For each of the matching data groups, determining whether the time difference of the matching data group meets the expected time difference range threshold; When it is determined that the time difference of the matching data group does not meet the expected time difference range threshold, the matching data group is determined to be an incorrect match, and the hysteresis data in the matching data group is identified as a fault point or a sag data point, the hysteresis data is removed from the fault time series data or the voltage sag time series data, and the fault time series data or the voltage sag time series data is updated; Based on the updated fault time series data or voltage sag time series data, the step of re-performing the timing error matching of the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point is performed to obtain a fault sag matching set, until the time difference between the matching data groups meets the expected time difference range threshold.

8. A voltage sag source location system, characterized in that: The system comprises: A data acquisition module is used to acquire fault data and voltage sag data monitored by multiple preset monitoring nodes in the target substation; wherein the fault data includes internal fault data and external fault data; a data sorting module, configured to sort the fault data and the voltage sag data according to time to obtain fault time series data and voltage sag time series data; the fault time series data includes a plurality of fault points and the fault occurrence time of the fault points; the voltage sag time series data includes a plurality of sag data points and the sag occurrence time and sag duration of the sag data points; a data matching module, configured to perform timing error matching on the fault time series data and the voltage sag time series data according to the fault occurrence time of each fault point and the sag occurrence time of each sag data point, to obtain a fault sag matching set; the fault sag matching set includes an internal fault sag matching set and an external fault sag matching set; a duplicate data screening module, configured to determine a plurality of duplicate dip data points according to the internal fault dip matching set and the external fault dip matching set; the duplicate dip data points are dip data points that exist in both the internal fault dip matching set and the external fault dip matching set; The data updating module is configured to re-divide the repeated dip data points into the internal fault dip matching set and the external fault dip matching set according to the dip duration of each repeated dip data point.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor performs the steps of the voltage sag source locating method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the method for locating a voltage sag source according to any one of claims 1 to 7 are implemented.

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