Active power distribution network grounding fault positioning method and system

Abstract

The invention provides an active power distribution network grounding fault positioning method and system, and relates to the technical field of fault positioning. The method comprises the following steps: when a ground fault occurs on the ground, firstly acquiring a detection timestamp by means of transient signal detectors arranged at two ends of a target line, and meanwhile, acquiring an electromagnetic wave timestamp of fault electromagnetic waves detected by an electromagnetic wave receiving device; then obtaining a target line length and a transient signal standard propagation speed, calculating a first fault initial moment according to the target line length and the transient signal standard propagation speed, and calculating a first fault position by combining a detection timestamp and the standard propagation speed; and then determining one or more second fault positions according to the first fault initial moment and the electromagnetic wave timestamp, and finally determining a final target fault position by combining the first fault position and the second fault position, thereby realizing accurate positioning of the active power distribution network grounding fault.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fault location, in particular to an active power distribution network grounding fault location method and system. BACKGROUND

[0002] With the rapid development of new power systems, a large number of active devices such as distributed power sources, energy storage devices, electric vehicle charging facilities are connected to the power distribution network, which makes the traditional power distribution network change to the active power distribution network. The bidirectional flow of power flow and the complex and changeable characteristics of fault current in the active power distribution network bring new challenges to the detection and location of grounding faults.

[0003] The traditional zero sequence current method detects the zero sequence current according to the fixed position of the measuring device. Usually, current transformers are installed at key nodes such as substation outlet ends and line towers, and the zero sequence current value is obtained by collecting the vector sum of three-phase currents. The system will preset a fixed current threshold. When the zero sequence current exceeds the threshold, it is determined that a grounding fault has occurred, and the fault section is preliminarily located combined with the current amplitude, direction and other characteristics, and then manually checked section by section.

[0004] However, in the active power grid, the fault current at the fault point may come from multiple directions, and the fixed measuring devices are far apart. The traditional method needs to check section by section from multiple directions under the condition of determining the approximate fault point, and the fault location method is inefficient, especially in complex terrain, the work intensity of the operation and maintenance personnel is large, and there is a high safety risk. SUMMARY

[0005] The present application provides an active power distribution network grounding fault location method and system, which is used to solve the problem of low positioning accuracy in traditional power distribution network grounding fault location, and improve the accuracy of fault location.

[0006] In a first aspect, the present application provides an active power distribution network grounding fault location method, which comprises: if a grounding fault occurs, acquiring a detection timestamp through a transient signal detector, and collecting an electromagnetic wave timestamp of a fault electromagnetic wave detected by an electromagnetic wave receiving device, the transient signal detector being arranged at both ends of a target line; acquiring the length of the target line and the standard signal propagation speed of the transient signal; calculating a first fault initial time based on the detection timestamp, the length of the line and the standard signal propagation speed; calculating a first fault position according to the first fault initial time, the detection timestamp and the standard signal propagation speed; determining one or more second fault positions based on the first fault initial time and the electromagnetic wave timestamp; and determining a target fault position in combination with the first fault position and the second fault position.

[0007] By adopting the technical scheme, the first fault position is calculated preliminarily by using the transient signal detectors arranged at both ends of the line through the double-end distance measurement method, which locks the fault range on a specific line. Then, the spatial positioning is performed by using the time difference of the electromagnetic wave signals reaching different receiving devices to obtain the second fault position. Finally, the 'on-line position' and the'spatial position' are combined and verified, the certainty result of one method is used to correct or confirm the uncertainty of the other method, and the advantages of the two positioning methods are complementary and cross-verified. The dual information fusion mode effectively overcomes the defects that the single distance measurement method is easily affected by environmental interference and parameter errors, thereby significantly improving the accuracy and reliability of the grounding fault positioning.

[0008] In combination with some embodiments of the first aspect, in some embodiments, the step of detecting the electromagnetic wave timestamp of the fault electromagnetic wave by the electromagnetic wave receiving device specifically includes: acquiring electromagnetic wave signals of the electromagnetic wave receiving device within the range set by the grounding fault detection device; when the electromagnetic wave signal detected by any electromagnetic wave receiving device exceeds a preset intensity threshold, triggering a timestamp mark to record multiple abnormal electromagnetic wave signal time data; using a digital filtering algorithm to process the abnormal electromagnetic wave signal time data to remove abnormal values caused by electromagnetic interference; when the abnormal electromagnetic wave signal time data of at least two different electromagnetic wave receiving devices are collected, sorting the abnormal electromagnetic wave signal time data in chronological order, and determining the earliest two abnormal electromagnetic wave signal time data as the electromagnetic wave timestamp.

[0009] By adopting the technical scheme, when collecting the electromagnetic wave timestamp, the signals are acquired within a limited range to ensure the relevance to the fault, the intensity threshold is set to trigger the recording of effective signals, the digital filtering is used to remove the interference and ensure the data purity, and the earliest two timestamps are selected to focus on the electromagnetic wave of the initial radiation of the fault. These steps are filtered layer by layer to remove noise and delayed signals, and reliable time reference is obtained to provide accurate input for subsequent positioning based on electromagnetic waves and reduce the positioning deviation caused by signal distortion.

[0010] In combination with some embodiments of the first aspect, in some embodiments, the step of calculating the first fault initial time based on the detection timestamp, the line length and the standard signal propagation speed includes: acquiring a first timestamp of the first-end transient signal detector and a second timestamp of the last-end transient signal detector in the target line; through the first timestamp, the second timestamp, the standard signal propagation speed and the line length, the following calculation can be performed: L=v(t1-t0)+v(t2-t0); where L is the line length, v is the standard signal propagation speed, t0 is the first fault initial time, t1 is the first timestamp, and t2 is the second timestamp; the first fault initial time is obtained by solving the above equation.

[0011] By adopting the technical solutions, the time and the position are decoupled, the time calculation error caused by the inability to determine the propagation distance in single-end measurement is eliminated, a unified, accurate and global time reference is obtained, and a high-precision starting point is provided for subsequent distance calculation based on the time.

[0012] With reference to the first aspect, in some embodiments, the step of calculating the first fault position according to the first fault initial time, the detection timestamp and the standard signal propagation speed comprises: obtaining a first timestamp t1 of a head-end transient signal detector in the target line and the first fault initial time t0; performing the following calculation: S = v(t1-t0); wherein S is a fault distance of the target grounding fault point from the head-end transient signal detector; obtaining position information and a fault occurrence direction of the head-end transient signal detector based on a line layout map, and determining the first fault position in combination with the fault distance.

[0013] By adopting the technical solutions, the time difference is converted into a physical distance, a specific point is locked relying on line topology information, the position result is strongly bound to the target line, a basic reference based on line physical characteristics is provided for fault positioning, and line attachment of the position is ensured.

[0014] With reference to the first aspect, in some embodiments, the step of determining one or more second fault positions based on the first fault initial time and the electromagnetic wave timestamp comprises: obtaining a first electromagnetic wave collection device and a second electromagnetic wave collection device that collect electromagnetic waves from the grounding fault point; determining a first time length for the first electromagnetic wave collection device to collect the electromagnetic waves and a second time length for the second electromagnetic wave collection device to collect the electromagnetic waves in combination with the first fault initial time; determining a first radius in combination with the first time length and a second radius in combination with the second time length according to an air transmission speed of the electromagnetic waves; determining a first circle according to the first radius with the first electromagnetic wave collection device as the origin and determining a second circle according to the second radius with the second electromagnetic wave collection device as the origin; obtaining all first electric wire sets intersecting the first circle and all second electric wire sets intersecting the second circle; determining an intersection point of the first circle and the second circle, and judging whether the intersection point falls on any electric wire in the first electric wire sets and the second electric wire sets; if so, taking the corresponding intersection point as a second fault position.

[0015] By adopting the technical scheme, firstly, based on the accurate initial fault time (t0), the time length for the electromagnetic wave to propagate to the earliest two receiving devices can be accurately calculated, and then according to the constant speed of the electromagnetic wave in the air, the time difference is converted into two accurate circles with each receiving device as the center and the propagation distance as the radius. In theory, the fault point must be located at the intersection of the two circles. Instead of directly taking the intersection as the result, the physical constraint condition of the power grid line is introduced, that is, whether the intersection falls on the actual power line. This step greatly improves the effectiveness of positioning and automatically excludes a large number of false intersections that are physically impossible to occur on the ground, buildings and the like, so as to converge the fuzzy mathematical solution into a limited candidate fault position with physical meaning.

[0016] In combination with some embodiments of the first aspect, in some embodiments, the step of determining the target fault position in combination with the first fault position and the second fault position comprises: if the second fault position is unique, determining the second fault position as the target fault position; and if the second fault position is not unique, determining the fault position closest to the first fault position from the second fault position as the target fault position.

[0017] By adopting the technical scheme, the results of the two positioning methods are fused: the first position guarantees the basic accuracy relying on the line, and the second position provides a spatial refinement reference. The optimal solution is selected by distance screening, solving the problem of selecting multiple suspected positions, realizing the complementary advantages of the two methods, and further improving the positioning accuracy.

[0018] In combination with some embodiments of the first aspect, in some embodiments, before the step of determining the fault position closest to the first fault position from the second fault position as the target fault position, the method further comprises: obtaining pre-stored geographic information routing of the target line; judging whether the second fault position with the minimum spatial distance falls within a preset buffer area of the geographic information routing of the target line; and only when the judgment result is yes, the second fault position is finally determined as the target fault position, otherwise, an alarm information is output to the receiving end to prompt that the positioning result has an attribution conflict.

[0019] By adopting the technical scheme, before determining the target fault position, it is verified whether it is within the buffer area of the target line. The preset buffer area is based on the line geographic routing, which limits a reasonable range. Only the positions within the area are recognized, otherwise, an alarm is given. This step filters the false results belonging to other lines although the distances are short, ensures the correct attribution of positioning, reduces the misjudgment caused by the interference of adjacent lines, and improves the reliability of the positioning system.

[0020] In a second aspect, the present application provides a fault location system, comprising: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is configured to store computer program code, the computer program code comprises computer instructions, the one or more processors invoke the computer instructions to enable the fault location system to perform the method as described in the first aspect and any possible implementation manner of the first aspect.

[0021] In a third aspect, the present application provides a computer readable storage medium comprising instructions that, when executed on a fault location system, cause the fault location system to perform the method as described in the first aspect and any possible implementation manner of the first aspect.

[0022] In a fourth aspect, the present application provides a computer program product that, when executed on a fault location system, causes the fault location system to perform the method as described in the first aspect and any possible implementation manner of the first aspect.

[0023] The one or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: 1. Since the technical means of combining the double-ended fault location based on the transient traveling wave along the conductor with the geometric location based on the time difference of arrival of the electromagnetic wave in space, and fusing and verifying the first and second fault locations obtained by the two methods are adopted, the technical problem that the single ranging method in the prior art is limited by its own principle, resulting in low positioning accuracy and poor reliability is effectively solved, and the advantages of the on-line location and the space location are complementary and mutually verified, thereby the comprehensive accuracy and reliability of fault location are significantly improved.

[0024] 2. Since the technical means of establishing an equation based on the time stamp of the transient signal detector at the beginning and end of the line, the length of the line and the propagation speed, associating the detection data with the physical parameters of the line through the bidirectional propagation characteristics of the transient signal, and inversely calculating the real occurrence time of the fault by mathematical calculation are adopted, the technical problem that the detection time stamp is directly used in the prior art and has errors is effectively solved, and the technical effect of providing an accurate time reference for fault location calculation and improving the reliability of the initial time is achieved.

[0025] 3. Since the technical means of combining the geometric location method based on the time difference of arrival of the electromagnetic wave with the physical routing information of the power grid line for verification are adopted, the technical problem that the spatial positioning algorithm in the prior art will produce physically impossible false solutions (such as the intersection not on any power line), resulting in invalid positioning results or serious multi-solution is effectively solved, and the technical effect of constraining the abstract mathematical intersection to the actual power line and automatically filtering out invalid candidate locations, greatly improving the accuracy and practicality of the second fault location is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flowchart of the active power distribution network grounding fault positioning method in the embodiments of the present application; Figure 2 is another flowchart of the active power distribution network grounding fault positioning method in the embodiments of the present application; Figure 3 is a schematic diagram of an entity device structure of the fault positioning system in the embodiments of the present application. DETAILED DESCRIPTION

[0027] The terms used in the following embodiments of the present application are only for the purpose of describing the specific embodiments and are not intended to be limiting on the present application. As used in the specification and the appended claims of the present application, the singular forms "a," "an," and "the" are intended to include plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "and / or" as used herein refer to and include any or all possible combinations of one or more of the listed items.

[0028] Hereinafter, the terms "first" and "second" are only for the purpose of description, and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features, and in the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0029] For ease of understanding, the method provided by the present embodiment is described in the flow. Please refer to Figure 1 is a flowchart of the active power distribution network grounding fault positioning method in the embodiments of the present application.

[0030] S101, if a grounding fault occurs, a detection time stamp is acquired through a transient signal detector, and an electromagnetic wave time stamp of the fault electromagnetic wave detected by an electromagnetic wave receiving device is collected, and the transient signal detector is arranged at both ends of the target line; Wherein, "grounding fault" refers to the incident state that the live phase conductor connects with the ground or grounding component through an abnormal path (such as trees, birds, damaged insulators, etc.) in the power system, which can produce intense arc discharge. "Transient signal detector" is a kind of high-frequency sensor, usually installed in the transformer substation at both ends of the line, used to capture the high-frequency current or voltage traveling wave signals generated in the fault moment and transmitted along the conductor at high speed. "Detection timestamp" is the precise time recorded by the high-precision clock inside the transient signal detector when it detects the arrival of the transient signal wave head. "Electromagnetic wave receiving device" refers to the sensor equipped with an antenna distributed in the power grid area, which is specially used to receive the electromagnetic wave pulse signals radiated by the fault arc in the air. "Fault electromagnetic wave" is the electromagnetic energy pulse radiated by the grounding fault arc to the surrounding space as a transient broadband emission source. "Electromagnetic wave timestamp" represents the precise time when the antenna of the electromagnetic wave receiving device first captures the fault electromagnetic wave signal exceeding the preset noise threshold. "Target line" refers to the specific power line section being monitored and having a fault, for example, the 10kV Chennan line from A substation to B substation.

[0031] In the continuous monitoring state of the normal operation of the power grid, once a grounding fault occurs, it is triggered instantaneously. The fault location system works as a whole, and its transient signal detectors distributed at both ends of the line and electromagnetic wave receiving devices scattered in the region are in a "standby" state. When a grounding fault occurs at any point on the target line, two physical phenomena will occur simultaneously: first, one or more steep traveling wave pulses (i.e., transient signals) propagate along the metal conductor to both ends of the line at near light speed; second, an electromagnetic wave pulse radiates in all directions in the air at the speed of light. The working process of the fault location system is as follows: first, for the capture of transient signals, detectors deployed at the beginning (e.g., A substation) and end (e.g., B substation) of the line will monitor the voltage or current of the line in real time. These detectors are equipped with complex trigger logic inside, such as based on signal mutation rate or energy change in a specific frequency band. When the wave head of the transient traveling wave generated by the fault passes through the detector, its amplitude or frequency will instantaneously break through the normal operation range, thereby triggering the detector. Once triggered, the detector will immediately lock and record the time provided by the high-precision synchronous clock (usually a GPS or Beidou timing module) at that moment, forming the beginning detection timestamp and the end detection timestamp, which are the core data for subsequent double-end traveling wave method positioning.

[0032] At the same time, the electromagnetic wave time stamp when the electromagnetic wave receiving device detects the fault electromagnetic wave is determined. Specifically, all electromagnetic wave receiving devices within the set range of the fault location system are in a long-time working mode, and they continuously collect electromagnetic wave signals in the surrounding space through the antenna and convert them into digital voltage values in real time. A high-speed comparison logic runs inside the system, which compares the instantaneous signal strength with a carefully set "preset strength threshold". The setting of this threshold is crucial: too low, it will cause the system to be frequently triggered by daily electromagnetic noise, resulting in a large amount of useless data; too high, it may miss the real fault signal with weak intensity. Therefore, the threshold is usually obtained by averaging based on long-term environmental noise statistics. Once the signal strength monitored by any receiving device breaks through the threshold instantaneously, the "time stamp marking" action will be triggered immediately.

[0033] The hardware of the electromagnetic wave receiving device sends a latch instruction to its built-in high-precision clock module to record the current time. At the same time, the receiving device packages this time stamp together with its ID, signal peak strength, waveform fragment and other auxiliary information and reports it to the central processor of the grounding fault detection device. Since the fault electromagnetic wave radiates in all directions, multiple receiving devices in the vicinity of the fault point will be triggered almost simultaneously within a very short time difference, and the system thus obtains a "abnormal electromagnetic wave signal time data" list containing multiple original time stamps.

[0034] The next second stage is "data cleaning and denoising". After collecting the original time stamp list, the system does not use them directly. Because strong electromagnetic interference in the real environment (such as lightning strikes tens of kilometers away, start-stop of large motors in nearby factories, or even switching operations on other feeders) can produce electromagnetic pulses with sufficient intensity, thus producing "abnormal values" unrelated to the target fault, which will seriously interfere with the positioning calculation. Therefore, the system starts the "digital filtering algorithm". For example, the system can use a clustering-based algorithm. It regards all time stamps received within a short time window (for example, 10 milliseconds) as an event cluster. Then it calculates the statistical properties of all time stamps in this cluster, such as mean and standard deviation. Any time stamp that deviates from the mean by more than 3 standard deviations is judged as an "abnormal value" produced by an independent interference event and is removed from the list. Another more robust method is the Hampel filter, which uses the median and median absolute deviation (MAD) to identify outliers, and is more tolerant of extreme outliers. Through this stage, only time stamps that are highly clustered in time, considered to be from the same grounding fault event, and have high credibility are left in the list.

[0035] The third stage is "effective data filtering and sorting". After filtering, the system needs to ensure that there is enough data for subsequent triangulation. The logic of this step requires that at least two effective time stamps from different receiving devices be collected. If the number of cleaned time stamps is less than 2, it means that the signal source is too weak or the receiving device coverage is insufficient, and this electromagnetic wave positioning fails. The system will mark and possibly rely only on the traveling wave method. If the condition is met, the system will accurately sort all remaining effective time data in chronological order, from early to late.

[0036] The fourth stage is "key information determination". In the sorted list, the system will select the first two time stamps. The selection of the "earliest" two is based on a key physical assumption: the direct signal with the shortest propagation path and the least reflection and diffraction will arrive earliest. Subsequent signals are likely to be reflected by buildings or diffracted by mountains, with longer propagation paths and later times, which will cause errors in positioning. Therefore, the two earliest arriving time stamps are considered to be the highest quality and most reflective of the straight-line distance from the fault point to the receiving device. These two time stamps are finally confirmed by the system as "electromagnetic wave time stamps".

[0037] S102, obtaining the line length of the target line and the standard signal propagation speed of the transient signal; "Line length" is used to represent the physical length of the conductor arranged between the transient signal detectors at the beginning and end of the target line, which is a static, pre-determined geographic information parameter. "Standard signal propagation speed of transient signal" refers to the theoretical or calibrated speed of the transient traveling wave generated by the fault in a specific type of conductor (such as overhead bare conductor or power cable). This speed is slightly less than the speed of light in a vacuum, for example, for overhead lines, the value is usually around 2.95 x 10^8 meters / second.

[0038] After the fault locating system receives the initial time stamp data collected in S101, it enters the calculation stage. It does not involve real-time measurement, but extracts the necessary information from the system's pre-configured static parameter library. When a fault occurs and is responded to by the positioning system, the system has determined which "target line" the fault occurred on (for example, by the identity ID of the triggered transient signal detector). At this time, the system needs to obtain two core physical parameters to convert the time information obtained in S101 into distance information.

[0039] The first parameter is the "line length". This data is usually obtained accurately by consulting design drawings, using GIS (Geographic Information System) data measurement, or through on-site surveying means such as GPS during the construction, reconstruction or deployment of the positioning system, and is entered into the database of the positioning system as an inherent attribute of the line. For example, the system database will have a line information table, with each row representing a line, containing fields such as line ID, line name, first end substation, last end substation, and "line length". The system can directly query this table according to the ID of the fault line to obtain the accurate value of L. The second parameter is the "standard signal propagation speed of transient signals". This speed is mainly determined by the dielectric constant and magnetic permeability of the medium around the conductor in theory. For overhead lines, the medium is mainly air, and the wave speed is very close to the speed of light. For power cables, due to the presence of insulating medium, the wave speed will be significantly reduced (about 0.5-0.6 times the speed of light). Therefore, vs is not a universal constant, but is closely related to the type of line. During system configuration, a standard and empirical "standard signal propagation speed" will be set according to whether the target line is overhead or cable, as well as the specific model specifications.

[0040] S103, calculating the first fault initial time based on the detection timestamp, the line length and the standard signal propagation speed; the first timestamp of the first end transient signal detector and the second timestamp of the last end transient signal detector in the target line can be obtained; through the first timestamp, the second timestamp, the standard signal propagation speed and the line length, the following calculation can be made: L = v(t1-t0) + v(t2-t0); where L is the line length, v is the standard signal propagation speed, t0 is the first fault initial time, t1 is the first timestamp, t2 is the second timestamp; the first fault initial time is obtained by solving the above equation.

[0041] Wherein, the "first end transient signal detector" refers to a high-speed sensor installed at the defined starting point of the line (e.g. the outgoing side of the power substation), and the time recorded by it is called "first timestamp t1". The "last end transient signal detector" refers to a similar sensor installed at the defined end point of the line (e.g. the other substation or the end of the line switch), and the time recorded by it is called "second timestamp (t2)". The "standard signal propagation speed v" is the rated speed of transient traveling wave propagation in this particular line medium, which is a pre-set physical constant. The "first fault initial time (t0)" is the core calculation target of this step, representing the absolute time point at which the fault physical phenomenon (such as arc discharge) actually occurs on the time axis.

[0042] After confirming that valid timestamps have been received from both ends of the target line and that the values of L and v for the line have been successfully retrieved from the database, the unknown quantity that cannot be determined by a single observation point, the fault occurrence time t0, can be solved.

[0043] S104, calculating a first fault location according to the first fault initial time, the detection timestamp and the standard signal propagation speed; The first timestamp t1 of the head-end transient signal detector in the target line and the first fault initial time t0 can be obtained; the following calculation is performed: S = v(t1-t0); wherein S is the fault distance of the target grounding fault occurrence point from the head-end transient signal detector; the position information and the fault occurrence direction of the head-end transient signal detector are obtained based on the line layout map, and the first fault location is determined in combination with the fault distance.

[0044] Wherein, the "first fault initial time" is the initial time point of the actual occurrence of the grounding fault obtained by backstepping through a fault location algorithm, is the starting time of the propagation of the transient signal to both ends of the line, and provides a time reference for subsequent fault distance calculation; the "fault distance" is the length of the target grounding fault occurrence point and the head-end transient signal detector on the target line path, reflects the distance of the fault point on the line, and the unit is usually meter; the "line layout map" is a drawing that details the direction of the target line, the tower position (overhead line), the cable laying path (cable line), the head-end and tail-end positions and other information, and assists in determining the actual geographical or line topology position of the fault point; the "position information" is the installation coordinates of the head-end transient signal detector in the power distribution network geographic information system (GIS) or the line topology, the tower number and other information, and is used for positioning the physical point of the detector; the "fault occurrence direction" refers to the extension direction of the fault point relative to the head-end transient signal detector on the target line, such as the direction along the line to the tail end or the specific branch direction when there is a branch, and clearly defines the propagation path direction of the fault on the line.

[0045] The fault location system obtains the "first timestamp" stored in the detector through the communication interface (such as wireless 4G / 5G, wired optical fiber communication) with the head end transient signal detector, and at the same time, calls the previously calculated "first fault initial time". These two time parameters are the core basis for subsequent calculation. Then, the fault distance is calculated according to the formula S = v (t1-t0), where v is the propagation speed of the transient signal in the target line, which can be obtained by line parameter test or table lookup (based on line material, insulation type, etc.), t1 is the first timestamp, and t0 is the first fault initial time. The time difference between the two is multiplied by the propagation speed to obtain the line length S from the fault point to the head end detector. Then, the system calls the line layout data, and queries the location information of the head end transient signal detector by means of geographic information system (GIS) or line topology database, such as the longitude and latitude coordinates on the GIS map, the number and coordinates of the tower. At the same time, according to the topology structure of the line and the propagation characteristics of the transient signal (the transient signal propagates from the fault point to the head end and the end, combined with the detection of the signal at the head end, it can be judged that the fault occurs in the direction away from the head end to the end, or between the head end and a branch point, etc.), the fault occurrence direction is determined. Finally, combined with the fault distance S, the distance is measured and the point is marked on the layout along the fault occurrence direction from the location of the head end detector, so as to determine the first fault location, such as in the overhead line layout, from the head end tower along the line direction, according to the calculated distance S, to determine the specific position of the fault point between two towers, or in the cable line, to determine the approximate interval of the fault point in a certain section of the cable.

[0046] S105, determining one or more second fault locations based on the first fault initial time and the electromagnetic wave timestamp; first, at least two receiving devices that detect the fault electromagnetic wave and their positions are determined. Then, the electromagnetic wave timestamp is subtracted from the first fault initial time to obtain the electromagnetic wave propagation time, and the distance (i.e. two radii) of the two devices to the fault point is calculated combined with the speed of light. Then, draw a circle with the two devices as the center and the corresponding radius, and find the intersection. Then, obtain the set of wires intersected by the two circles, and judge whether the intersection point falls on the common wire set. The intersection point that falls on the common wire set is the second fault location, which may be one or more. The detailed steps are explained in S201-S208, which will not be repeated here.

[0047] S106, determining the target fault location in combination with the first fault location and the second fault location.

[0048] In this step, if the second fault location is unique, the second fault location is determined as the target fault location; if the second fault location is not unique, the fault location closest to the first fault location is determined from the second fault location as the target fault location. Wherein, the “second fault location” refers to the suspected location of the ground fault in space based on the positioning of the electromagnetic wave signal, which can be one or more, used to supplement the fault positioning information from the spatial dimension, and an example is two geographic coordinate points positioned by a double electromagnetic wave receiving device; the “target fault location” is the accurate fault location finally determined by the fault positioning process for guiding operation and maintenance, which needs to be determined by comprehensively considering the positioning results in multiple dimensions, and is the basis for subsequent fault isolation and repair; the “first fault location” is the fault point position positioned on the target line based on the transient signal. The “distance” refers to the spatial straight-line distance or the line path distance (selected according to the positioning scene, which is the spatial straight-line distance by default), used to measure the proximity of different fault location candidates and the first fault location.

[0049] The system extracts the set data of the second fault location from the execution result of S105. If the set contains only one location point, it means that the spatial positioning result based on the electromagnetic wave is unique, and the location passes the line set screening (the intersection falls within the effective section of the line), so the location has uniqueness in the spatial dimension. Since the first fault location is positioned from the line topology dimension and the second fault location is positioned from the spatial dimension, they should theoretically point to the same fault point, so the only second fault location is directly determined as the target fault location without additional screening. For example, the second fault location has only one coordinate point (30° N, 120° E), and it matches the line topology logic of the first fault location, so it is directly output as the target.

[0050] If the second fault location set contains multiple location points (commonly two, because two circles intersect at most two intersection points), the system will call the first fault location data output by S104, and convert the first fault location into a spatial coordinate (such as mapping into latitude and longitude coordinates by using the line head detector position, line direction, etc.) with the help of the distribution network GIS system. Then, the system traverses each location point in the second fault location set, and calculates the spatial straight-line distance between each second fault location and the first fault location using the spatial coordinate distance calculation formula. After that, the distance values are compared and sorted, and the second fault location with the smallest distance is selected. The basis of this logic is that the first fault location is positioned based on the line physical parameters (transient signal propagation, line length, etc.), and has high reliability, so the second fault location closest to it is more likely to be the real fault point (because the fault point needs to meet both the line topology and the spatial electromagnetic wave propagation law).

[0051] If the distance between the two intersection points is small, such as less than a preset distance threshold, there will be such a situation: the A line fault is detected by the traveling wave method, and the fault point is calculated to be about 5 kilometers away from the starting end (this is the first fault position). The electromagnetic wave method is located by two receivers, and two intersection points (the second fault position) are calculated. According to the previous method, we select the intersection point closest to the "5 kilometers away from the A line" point. The problem is: this closest intersection point, although spatially close, may just fall on the parallel B line next to it, not on the A line we detected at the beginning. Without additional verification steps, the system will mistakenly report the fault as a B line fault, causing the maintenance personnel to go to the wrong line for troubleshooting, which goes against the original intention of the invention to improve efficiency and accuracy.

[0052] Therefore, in this case, the pre-stored geographic information route of the target line can be obtained first; it is judged whether the second fault position with the smallest spatial distance falls within the preset buffer area of the geographic information route of the target line; and only when the judgment result is yes, the second fault position is finally determined as the target fault position, otherwise, an alarm information is output to the receiving end to prompt that the positioning result has an attribution conflict. The "pre-stored geographic information route" refers to the geographic spatial trend data about the target line pre-stored in the fault positioning system or the power distribution network GIS (Geographic Information System), including the coordinate sequence of the line, the tower position, the cable laying path and other information, which is used to clearly define the actual physical trend of the line, like recording the accurate geographic coordinates of each section of the line after leaving the transformer substation; the "preset buffer area" is a certain width of the belt-shaped area set around the geographic information route of the target line, which is used to contain the position deviation of the line caused by construction errors, geographic surveying and mapping accuracy, etc., to judge whether the fault position is reasonably attributed to the target line, for example, the range of 5 meters on both sides of the line center line; the "alarm information" is the prompt content generated by the system when the attribution of the fault position is questionable, which is used to inform the maintenance personnel that the positioning result may not be accurate and needs to be manually checked; and the "receiving end" is a terminal device that receives the alarm information, such as the mobile phone of the maintenance personnel, the on-duty terminal of the power distribution network monitoring center, etc.

[0053] Specifically, the fault positioning system first performs "geographic information route acquisition": the system calls the power distribution network GIS platform through an interface, or directly extracts the pre-stored geographic information route data of the target line from the locally stored line database. The data exists in the form of a digitized coordinate sequence, for example, including the starting point of the line (the coordinate of the transformer substation outlet cabinet position, north latitude 30°15', east longitude 120°30'), the coordinates of the towers passing through (such as a tower coordinate every 500 meters), the end point (the coordinate of the distribution room inlet cabinet position), and the trend type of the line (such as the sag curve of the overhead line, the fitting curve of the underground laying path of the cable line).

[0054] Next, the "buffer area construction" is performed: according to the type of the target line (overhead line or cable line), voltage level and other factors, the width of the preset buffer area is determined. For a 10kV overhead line, considering the tower spacing, conductor sag and other factors, the buffer area width can be set to 5 meters on both sides of the line center line; for a cable line, due to the relatively fixed laying path, the buffer area width can be set to 2 meters on both sides. Based on the coordinate sequence of the geographic information routing, the system uses the GIS spatial analysis algorithm to construct the corresponding strip-shaped buffer area along the line direction, for example, by performing buffer zone analysis on the line coordinate sequence to generate a continuous polygonal area around the line, representing the preset buffer range. Then, the "position attribution judgment" is performed: the system extracts the coordinates of the second fault position with the smallest spatial distance determined in S701 (such as north latitude 30°15′01″, east longitude 120°30′02″), calls the GIS spatial inclusion judgment function, and checks whether the coordinate point falls within the constructed preset buffer area. The judgment logic is based on the spatial relationship between the point and the polygon: if the fault position coordinates are within the polygon range of the buffer area (including the boundary), it is determined that "it falls within the buffer area"; if it is completely outside the polygon, it is determined that "it does not fall within".

[0055] Finally, the "result handling" is performed: when the judgment result is "yes" (the fault position falls within the buffer area), it means that the second fault position is reasonably attributed to the target line in geographical space, and the system finally determines it as the target fault position and outputs it to the operation and maintenance system for guiding on-site fault repair; when the judgment result is "no" (the fault position does not fall within the buffer area), the system determines that the positioning result has attribution conflict (i.e. the position may belong to other lines or non-line areas, not consistent with the geographical routing logic of the target line), and immediately generates an alarm information. The alarm information contains the fault position coordinates, the target line name, the buffer area range and other contents, which are sent to the preset receiving end through wired or wireless communication methods (such as 4G / 5G network, optical fiber communication) to remind the operation and maintenance personnel to intervene and confirm, avoiding invalid maintenance based on incorrect positioning.

[0056] In the embodiments of the present application, through precise collection of double signal timestamps, integration of line physical parameters, mathematical backstepping of fault initial time, the "first fault position in line topology dimension" and "second fault position in spatial geometry dimension" double positioning dimensions are constructed, and the double dimension result fusion is realized through uniqueness judgment and distance screening. At the same time, in the signal collection stage, the intensity threshold screening and digital filtering are used to remove interference, and in the position calculation stage, the line layout map and geographic information are relied on to ensure the relevance, so as to effectively avoid the limitations of traditional single-source positioning, solve the problems of low positioning accuracy, poor scene adaptability and ambiguous fault position of active distribution network grounding fault positioning, and further realize the significant improvement of positioning accuracy.

[0057] After the above is combined, the following further more specific flow description of the method S105 step provided by the present embodiment is provided. Please refer to Figure 2 , another flow diagram of the active power distribution network grounding fault positioning method in the embodiment of the present application.

[0058] S201, acquiring a first electromagnetic wave collection device and a second electromagnetic wave collection device that collect electromagnetic waves from a grounding fault point; Among them, the "first electromagnetic wave collection device" refers to a detection device deployed in the power distribution network for capturing electromagnetic wave signals generated by the grounding fault point, the "second electromagnetic wave collection device" is another detection device of the same type used in cooperation with the first electromagnetic wave collection device, usually maintaining a certain spatial distance from the first device, and together constituting a double-point positioning reference, and the "electromagnetic waves from the grounding fault point" refers to high-frequency electromagnetic signals radiated to the surrounding space at the moment of grounding fault occurrence (such as the arc generated by the phase line grounding).

[0059] After the grounding fault occurs, the fault point will radiate electromagnetic wave signals to the surrounding space. The fault positioning system needs to scan all online electromagnetic wave collection devices in real time and screen out devices that detect abnormal electromagnetic wave signals after the initial moment of the fault. The screening conditions include signal strength exceeding a preset threshold, signal waveform conforming to fault characteristics (such as steep rising edge), etc. The real-time state and position data of all electromagnetic wave collection devices are acquired. Then, according to the first fault initial moment calculated by the transient signal detector, the devices that detect electromagnetic wave signals within a preset time window (such as 0.1 seconds) after the moment are screened out. Finally, according to the signal arrival time sequence, the earliest two devices are selected as the first and second electromagnetic wave collection devices.

[0060] S202, determining a first time length of the first electromagnetic wave collection device collecting electromagnetic waves and a second time length of the second electromagnetic wave collection device collecting electromagnetic waves in combination with the first fault initial moment; The first time length represents the time interval from the first fault initial moment to the detection of the electromagnetic wave signal by the first electromagnetic wave collection device, and the second time length is the same.

[0061] S203, determining a first radius in combination with the first time length and a second radius in combination with the second time length according to the air transmission speed of the electromagnetic wave; Among them, the air transmission speed of the electromagnetic wave refers to the propagation speed of the electromagnetic wave in the air, usually taking the speed of light, the first radius is the straight line distance corresponding to the time required for the electromagnetic wave to propagate from the fault point to the first electromagnetic wave collection device, and the second radius is the straight line distance corresponding to the time required for the electromagnetic wave to propagate from the fault point to the second electromagnetic wave collection device.

[0062] Specifically, the system first reads the standard value of the electromagnetic wave transmission speed in the air from the configuration file. Then it is multiplied by the first time length and the second time length respectively to obtain the first and second radii.

[0063] S204, determining a first circle according to the first radius with the first electromagnetic wave collection device as the origin, and determining a second circle according to the second radius with the second electromagnetic wave collection device as the origin; The "first circle" is defined by the system as: in the geographic coordinate system, the set of all points whose distance from the center point of "first electromagnetic wave collection device coordinates" is equal to "first radius". Similarly, the second geometric object is "second circle", which is defined as the set of all points whose distance from the center point of "second electromagnetic wave collection device coordinates" is equal to "second radius".

[0064] According to the basic principle of time of arrival positioning method, the real fault point is an electromagnetic wave source, so it must be located on the circumference of the two circles. In other words, the real fault point must fall on the trajectory of the "first circle" and fall on the trajectory of the "second circle". Then, from a geometric point of view, this point can only be the intersection of the two circles logically.

[0065] First, the system retrieves the accurate coordinates of the first and second electromagnetic wave collection devices from the geographic information system (GIS) and converts them into coordinate values in the plane rectangular coordinate system to simplify distance calculation. Subsequently, according to the first radius and the second radius, a circular boundary is drawn respectively with the two devices as the center. During the drawing process, the influence of the earth's curvature on long-distance positioning needs to be considered: when the radius is less than 10 kilometers, it can be approximately processed according to plane geometry; when the radius is greater than 10 kilometers, the spherical distance formula needs to be used to calculate the longitude and latitude of each point on the circumference to ensure the spatial accuracy of the circle. For example, for the second device coordinates (116.5°E, 39.9°N) and the second radius of 800 meters, the system will generate a circular area containing all points with a spherical distance of 800 meters from the point.

[0066] In some embodiments, the determination of the circle can be achieved in various ways: optionally, the spatial analysis function of the GIS platform is used to call the "buffer analysis" tool, with the device coordinates as input and the radius as parameter, to directly generate a circular buffer zone (i.e. circle) and automatically store the boundary coordinate set of the circle; optionally, geometric calculation is realized through programming, first define the center coordinates (x1, y1) and (x2, y2), then calculate the coordinates of n points (such as 360 points, one point per 1°) evenly distributed on the circumference according to the radii r1 and r2, and finally connect these points in turn to form a closed circle.

[0067] S205, obtaining all first electric wire sets intersecting the first circle and all second electric wire sets intersecting the second circle; wherein, the first circle refers to a circular region with the first electromagnetic wave collection device as the center and the first radius as the boundary; intersect refers to the physical path of the power line and the circle exist spatial overlap or intersection, that is, a certain paragraph of the line is located in the circle or passes through the circle boundary; the first wire set refers to the set of all power lines that meet the intersection condition with the first circle, including overhead lines, cables, branch lines, etc., each line in the set contains its path coordinates, voltage level, line type, etc. attribute information. Similarly, the second circle refers to a circular region with the second electromagnetic wave collection device as the center, and the second wire set refers to the set of all power lines that intersect with the circle. For example, if the first circle covers a 300-meter section of a 10kV overhead line, the overhead line will be included in the first wire set.

[0068] This step is performed after the first and second circles are determined, and the purpose is to filter out candidate lines that may contain fault points from all lines in the distribution network, reducing the scope of subsequent positioning calculation. First, the system retrieves the spatial path data of all lines from the distribution network GIS database. Then, for each line and the corresponding circle, spatial intersection is judged: for the first circle, all lines are traversed to check if the line intersects with the circle; for the second circle, the same operation is performed. The standard for judging intersection is that any segment of the line and the boundary or interior of the circle overlap, that is, at least one of the two endpoints of the segment is located in the circle, or the segment passes through the circle boundary. For example, the path of a certain cable extends from outside the circle to inside the circle, and has a length of 50 meters inside the circle, so the cable belongs to the first wire set. In addition, the system will also preprocess the filtered wire set to remove lines that are already out of service or under maintenance, and only keep lines that are in operation to improve positioning accuracy. For complex distribution network topology (such as multiple branch lines), the system will keep all branch lines that meet the conditions to avoid missing the line where the fault point is located.

[0069] S206, determine the intersection point of the first circle and the second circle, and determine whether the intersection point falls on any wire in the first wire set and the second wire set; wherein, the intersection point of the first circle and the second circle refers to the point where the two circular regions intersect in space, that is, the point that satisfies the distance to the first device equal to the first radius and the distance to the second device equal to the second radius, the two circles have at most 2 intersection points and at least 0 intersection points; fall in refers to the spatial coordinates of the intersection point coincide with the path coordinates of a certain wire or within a predetermined error range (such as within 1 meter), that is, the intersection point is located on the physical path of the wire; the first wire set and the second wire set refer to the line set that intersects with the two circles respectively; any wire refers to any line in the set.

[0070] Specifically, the step is performed after the first and second wire set is acquired, and is a key link for determining the candidate position of the fault point. The step is divided into two sub-steps: first, the intersection points of the two circles are calculated, and then it is verified whether the intersection points are on the candidate line. In the calculation of the intersection points, the system substitutes the center coordinates (x1, y1) and (x2, y2) and the radii r1 and r2 of the two circles into the circle equations to solve the equations: (x-x1) 2 +(y-y1) 2 =r1 2 (x-x2) 2 +(y-y2) 2 =r2 2 The intersection point coordinates (x a , y a ) and (x β , y β ) are obtained through algebraic operation (if they exist). If the two circles have no intersection point (for example, the distance between the centers is greater than r1+r2 or less than |r1-r2|), the step S208 is directly entered; if the intersection point exists, the next step is verified.

[0071] If it falls in, the step S207 is performed; If it does not fall in, the step S208 is performed.

[0072] S207, the corresponding intersection point is taken as the second fault position; First, the system collects all the intersection points that meet the conditions in S206 to form a preliminary candidate position list. If there is only one intersection point in the list, the intersection point is directly taken as the second fault position; if there are multiple intersection points (for example, two intersection points fall on different candidate lines), the intersection points need to be preliminarily screened. For example, an intersection point that falls on a line that intersects both the first and second circles (i.e., the line on which the intersection point is located intersects both the first and second circles) is preferentially selected, because such a line is more likely to be the line on which the fault point is located. For example, the intersection point B falls on the line L2, and L2 belongs to both the first and second wire sets, so the priority of B is higher than that of the intersection point C that falls on a line in the first wire set. In addition, the system adds attribute information to each second fault position, including the corresponding intersection point coordinates, the line name, the distance to the two devices, etc., so as to be combined with the first fault position for subsequent analysis. If there are multiple second fault positions, the system will sort them according to the priority (for example, according to the estimated distance from the first fault position from small to large), to provide a basis for finally determining the target fault position.

[0073] S208, it is determined that there is no second fault position.

[0074] Wherein, the absence of the second fault position means that in the determination of S206, neither of the intersection points of the two circles falls on any of the electric wires of the first electric wire set or the second electric wire set, or the two circles have no intersection point, resulting in a state that the fault point candidate position cannot be determined by the electromagnetic wave positioning method.

[0075] In some embodiments, the first circle can also be a circular region formed by projecting the first radius (the straight-line distance from the fault point to the first device) to the XY plane (a plane parallel to the ground) from the Z-axis positive direction downward after defining the longitudinal direction (a direction perpendicular to the ground) as the Z-axis with the actual geographic position of the first electromagnetic wave collection device as the world coordinate origin. Similarly, the second circle is a circular region formed by the same projection logic with the second electromagnetic wave collection device as the world coordinate origin.

[0076] In determining the first electric wire set intersecting with the first circle, the electric wires in the power distribution network need to be subjected to coordinate mapping processing: the three-dimensional path coordinates of each electric wire and the coordinates of the cable laying path are projected to the XY plane to obtain the two-dimensional mapping line of the electric wire (only x and y coordinates are retained, and z coordinates are ignored). Then it is determined whether the two-dimensional mapping line and the first circle (the projected circle in the XY plane) have an intersection relationship - if any segment of the mapping line passes through the circle boundary, or a certain segment of the mapping line falls completely within the circle, the electric wire is included in the first electric wire set. This projection-based processing method, on the one hand, avoids the three-dimensional space calculation complexity caused by the height difference of the power distribution network lines, simplifying the mathematical model of the intersection judgment; on the other hand, since the fault point is usually located at the conductive part of the line (the height is relatively fixed), the projection of the circle and the mapping line after the projection can more accurately reflect the horizontal position correlation of the fault point, reducing the positioning error introduced by the height factor, and further improving the judgment accuracy of the second fault position.

[0077] In the embodiments of the present application, since the positioning reference is constructed by the two electromagnetic wave collection devices in cooperation, the electromagnetic wave propagation time is accurately calculated in combination with the fault initial time and the device detection timestamp, and then the time is converted into a spatial radius according to the air transmission speed of the electromagnetic wave and the corresponding positioning circle is drawn, and the candidate lines intersecting with the circle are selected based on the topology of the power distribution network, the second fault position is determined by verifying the line attribution through the intersection points of the two circles, and the self-checking and backup processing procedures are set for the positioning failure scenarios, forming a complete positioning logic from device cooperation to spatial circle positioning, line matching, intersection point verification, and abnormal response, so that the fault positioning boundary can be narrowed layer by layer from the spatial range to the line attribution, effectively avoiding the range ambiguity problem of single device positioning, the invalid intersection point interference without line correlation, and the defect of lacking response mechanism after positioning failure, thereby effectively solving the technical pain point of "excessive candidate range leading to low troubleshooting efficiency" in the traditional active power distribution network electromagnetic wave grounding fault positioning, and finally contributing to the accurate locking of the candidate position of the active power distribution network grounding fault.

[0078] The fault locating system in the embodiments of the present application will be described from the perspective of hardware processing. Please refer to Figure 3 FIG. 1 is a schematic diagram of an entity device structure of the fault locating system in the embodiments of the present application.

[0079] It should be noted that Figure 3 The structure of the fault locating system shown is only an example and should not bring any limitation to the function and use range of the embodiments of the present application.

[0080] As Figure 3 shown, the fault locating system includes a central processing unit (CPU) 301, which can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 302 or programs loaded from a storage portion 308 into a random access memory (RAM) 303, such as performing the method described in the above embodiments. In the RAM 303, various programs and data required for system operation are also stored. The CPU 301, the ROM 302, and the RAM 303 are connected to each other through a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0081] The following components are connected to the I / O interface 305: an input portion 306 including an audio input device, a button switch, and the like; an output portion 307 including a liquid crystal display (LCD) and an audio output device, an indicator, and the like; a storage portion 308 including a hard disk and the like; and a communication portion 309 including a network interface card such as a LAN (Local Area Network) card, a modem, and the like. The communication portion 309 performs communication processing via a network such as the Internet. A drive 310 is also connected to the I / O interface 305 as needed. A removable medium 311 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, and the like is mounted on the drive 310 as needed, so that a computer program read therefrom is installed in the storage portion 308 as needed.

[0082] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program in accordance with embodiments of the present application. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program comprising computer programs for executing the methods illustrated by the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via the communication section 309, and / or installed from the removable medium 311. When the computer program is executed by the central processing unit (CPU) 301, various functions defined in the present application are executed.

[0083] Note that specific examples of computer readable storage media can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present application, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0084] The flowcharts and block diagrams in the attached drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowcharts or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved.

[0085] In particular, the fault location system of the present embodiment comprises a processor and a memory, and the memory stores a computer program, which, when executed by the processor, implements the active distribution network grounding fault location method provided by the above-mentioned embodiments.

[0086] As another aspect, the application also provides a computer readable storage medium, which can be included in the fault locating system described in the above embodiments, or can exist independently without being assembled into the fault locating system. The storage medium carries one or more computer programs, which, when executed by a processor of the fault locating system, enable the fault locating system to implement the active power distribution network grounding fault locating method provided in the above embodiments.

[0087] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those ordinarily skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0088] In the above embodiments, according to the context, the term "when" can be interpreted as meaning "if" or "after" or "in response to determining" or "in response to detecting". Similarly, according to the context, the phrase "upon determining" or "if detecting (a stated condition or event)" can be interpreted as meaning "if determining" or "in response to determining" or "upon detecting (a stated condition or event)" or "in response to detecting (a stated condition or event)".

[0089] Those ordinarily skilled in the art can understand that all or part of the processes in the above method embodiments can be instructed by a computer program to relevant hardware, and the program can be stored in a computer readable storage medium, and when executed, can include the processes of the above method embodiments. The foregoing storage medium includes ROM or random storage memory RAM, magnetic disc or optical disc, and various program code storage media.

Claims

1. An active power distribution network ground fault location method, characterized in that, The method comprises: If a ground fault occurs, a detection timestamp is obtained by a transient signal detector arranged at both ends of a target line, and an electromagnetic wave timestamp of a fault electromagnetic wave detected by an electromagnetic wave receiving device is collected; The length of the target line and the standard signal propagation speed of the transient signal are obtained; A first fault initial time is calculated based on the detection timestamp, the length of the line and the standard signal propagation speed; A first fault position is calculated according to the first fault initial time, the detection timestamp and the standard signal propagation speed; One or more second fault positions are determined based on the first fault initial time and the electromagnetic wave timestamp; The target fault position is determined by combining the first fault position and the second fault position.

2. The method of claim 1, wherein, The step of collecting the electromagnetic wave timestamp of the fault electromagnetic wave detected by the electromagnetic wave receiving device specifically comprises: The electromagnetic wave signals of the electromagnetic wave receiving devices within the set range of the ground fault detection device are obtained; When the electromagnetic wave signal detected by any electromagnetic wave receiving device exceeds a preset intensity threshold, a timestamp marker is triggered, and a plurality of abnormal electromagnetic wave signal time data are recorded; The abnormal electromagnetic wave signal time data are processed by using a digital filtering algorithm to remove abnormal values caused by electromagnetic interference; when the abnormal electromagnetic wave signal time data of at least two different electromagnetic wave receiving devices are collected, the abnormal electromagnetic wave signal time data are sorted in chronological order, and the earliest two abnormal electromagnetic wave signal time data are determined as the electromagnetic wave timestamp.

3. The method of claim 1, wherein, The step of calculating the first fault initial time based on the detection timestamp, the length of the line and the standard signal propagation speed comprises: The first timestamp of the first-end transient signal detector and the second timestamp of the last-end transient signal detector in the target line are obtained; the first timestamp, the second timestamp, the standard signal propagation speed and the length of the line are calculated as follows: L=v(t1-t0)+v(t2-t0); Wherein, L is the length of the line, v is the standard signal propagation speed, t0 is the first fault initial time, t1 is the first timestamp, and t2 is the second timestamp; The first fault initial time is obtained by solving.

4. The method of claim 1, wherein, The step of calculating the first fault position according to the first fault initial time, the detection timestamp and the standard signal propagation speed comprises: The first timestamp t1 of the first-end transient signal detector and the first fault initial time t0 in the target line are obtained; The following calculation is performed: S=v(t1-t0); Wherein, S is the fault distance of the target ground fault occurrence point from the first-end transient signal detector; Based on the line layout map, the position information and the fault occurrence direction of the first-end transient signal detector are obtained, and the first fault position is determined in combination with the fault distance.

5. The method of claim 1, wherein, The step of determining one or more second fault positions based on the first fault initial time and the electromagnetic wave timestamp comprises: First electromagnetic wave collection equipment and second electromagnetic wave collection equipment that collect electromagnetic waves from the ground fault point are obtained; Determine a first time length of electromagnetic waves collected by the first electromagnetic wave collection device and a second time length of electromagnetic waves collected by the second electromagnetic wave collection device according to the first fault initial time; Determine a first radius according to the first time length and a second radius according to the second time length according to the air transmission speed of electromagnetic waves; Determine a first circle according to the first radius with the first electromagnetic wave collection device as the center and determine a second circle according to the second radius with the second electromagnetic wave collection device as the center; Obtain all first electric wire sets intersecting the first circle and all second electric wire sets intersecting the second circle, determine the intersection point of the first circle and the second circle, and determine whether the intersection point falls on any electric wire in the first electric wire set and the second electric wire set; If the intersection point falls on any electric wire, the corresponding intersection point is taken as the second fault position.

6. The method of claim 1, wherein, The step of determining the target fault position according to the first fault position and the second fault position includes: If the second fault position is unique, the second fault position is determined as the target fault position; If the second fault position is not unique, the fault position closest to the first fault position is determined as the target fault position from the second fault position.

7. The method of claim 6, wherein, Before the step of determining the fault position closest to the first fault position as the target fault position from the second fault position, the method further includes: Obtain the pre-stored geographic information route of the target line; Determine whether the second fault position closest in space distance falls within the preset buffer area of the geographic information route of the target line; and only when the determination result is yes, the second fault position is finally determined as the target fault position, otherwise, an alarm information is output to the receiving end to prompt that the positioning result has an attribution conflict.

8. A fault location system characterized by, The fault positioning system includes one or more processors and a memory; the memory is coupled with the one or more processors, the memory is used to store computer program codes, the computer program codes include computer instructions, and the one or more processors invoke the computer instructions to enable the fault positioning system to perform the method according to any one of claims 1-7.

9. A computer-readable storage medium comprising instructions, characterized in that, When the instructions run on the fault positioning system, the fault positioning system performs the method according to any one of claims 1-7.

10. A computer program product, characterised in that, When the computer program product runs on the fault positioning system, the fault positioning system performs the method according to any one of claims 1-7.

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