A method and system for comprehensive determination of multiple lightning trip-out of a power transmission line

Abstract

The application discloses a kind of power transmission line multiple lightning trip integrated determination method and system, and is fused meteorology, lightning location, optical image, tower lightning withstand performance, wave recording waveform, travelling wave waveform, relay protection action and the multi-dimensional information such as fault point feature carries out comprehensive discrimination.Judge whether multiple lightning occurs in power transmission corridor first, then calculate tower lightning withstand level to judge whether lightning can cause trip, then confirm whether line is subjected to multiple lightning by waveform analysis, finally verify lightning trip fact, carry out logical and operation to the result of four steps, output final determination.The application can realize the online fast determination of multiple lightning trip in seconds, and determination accuracy is high.

Description

Technical Field

[0001] This invention relates to the field of transmission line protection technology, specifically a comprehensive judgment method and system for multiple lightning strike tripping of transmission lines, which is suitable for the power grid dispatch center to quickly and accurately identify the types of lightning strike faults. Background Technology

[0002] Multiple lightning strikes account for a significant proportion of natural lightning events. Statistics show that over 50% of negative ground flashes involve multiple return strokes, and the characteristics of multiple lightning discharges vary significantly with thunderstorm intensity and terrain conditions. Transmission lines and towers, as tall, overhead outdoor structures, have long corridors and complex terrain along their routes, making them far more susceptible to multiple lightning strikes than ordinary buildings. Multiple lightning strikes inject continuous high-amplitude currents into the lines within a short period, not only exacerbating the risk of insulator flashover and erosion but also potentially triggering cascading trips of circuit breakers, seriously threatening the safe and stable operation of the power grid.

[0003] Currently, the identification of multiple lightning strikes on transmission lines mainly relies on single information sources such as traveling wave ranging devices, fault recorders, or lightning location systems, and the criteria for judgment are often limited to a single electrical quantity characteristic. For example, some existing technologies distinguish between single and multiple lightning strikes based on the similarity of traveling wave waveforms, or determine multiple lightning strikes based on the slope of the fitted straight line of the fault record waveform. However, in actual fault scenarios, the transient waveforms generated by multiple lightning strikes are highly superimposed in the time and frequency domain with those of single lightning strikes, induced lightning in adjacent areas, circuit breaker overvoltages, and various noise signals in the system. The waveform similarity is high, and existing single criteria are difficult to effectively eliminate interference factors. This makes it very easy to misjudge non-multiple lightning strike faults as multiple lightning strikes, or to miss real multiple lightning strike events due to unclear characteristics.

[0004] More significantly, existing fault diagnosis processes mostly rely on post-fault manual verification or offline waveform comparison analysis, lacking online real-time processing mechanisms. From the occurrence of a fault to the dispatcher obtaining preliminary diagnosis results, several hours or even longer are often required, completely failing to meet the actual needs of the power grid for millisecond-level rapid fault response. This time delay not only prolongs unplanned line outages, directly weakening power supply reliability, but also delays the timely adjustment of reclosing and protection coordination strategies. As the power grid expands and the frequency of thunderstorms increases, these problems become increasingly prominent.

[0005] Therefore, there is an urgent need to study a comprehensive judgment method that can integrate multi-dimensional features and has the ability to quickly identify them online, so as to fundamentally break through the technical bottleneck of traditional single information source and offline analysis mode. Summary of the Invention

[0006] This invention provides a comprehensive method and system for determining multiple lightning strikes that cause power transmission lines to trip. It can efficiently and accurately determine whether a power transmission line has been struck by multiple lightning strikes based on multi-dimensional information such as electrical, meteorological, and equipment status, thus meeting the needs of refined operation and maintenance of the power grid.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A comprehensive method for determining multiple lightning strike tripping of transmission lines includes the following steps:

[0009] Acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of the transmission line fault trip. Based on the meteorological information, lightning location system records, and optical images of the transmission corridor, determine whether multiple lightning strikes have occurred in the transmission corridor. If so, number each lightning strike and output the first determination result.

[0010] Based on the first determination result, the tower closest to the lightning strike location is determined, and the structural parameters, terrain parameters and lightning activity parameters of the tower are obtained. The backflash lightning withstand level and the dangerous lightning current range of the backflash lightning strike are calculated. Based on the lightning current amplitude of each lightning strike corresponding to each number, it is determined whether there is a target lightning strike that can cause the tower to trip due to backflash lightning strike or backflash lightning strike. The second determination result is then output.

[0011] The fault waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment are obtained. Based on the fault waveform and distributed traveling wave waveform, it is determined whether the transmission line has been struck by multiple lightning strikes. When multiple lightning strikes are struck, the location and time of the lightning strike are calculated and the third determination result is output.

[0012] Obtain relay protection action information, switch quantity changes and fault point characteristic information, verify whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes and fault point characteristic information, and output the fourth judgment result;

[0013] A logical AND operation is performed on the first determination result, the second determination result, the third determination result, and the fourth determination result to obtain a comprehensive determination result. When the comprehensive determination result is true, it is determined that the transmission line has tripped due to multiple lightning strikes.

[0014] Furthermore, the step of determining whether multiple lightning strikes have occurred within the transmission corridor based on the meteorological information, lightning location system records, and optical images of the transmission corridor specifically includes:

[0015] Based on the weather type, temperature, humidity, and warning level in the meteorological information, determine whether the time of the fault trip occurred during thunderstorms;

[0016] Analyze the records of the lightning location system to extract the number of lightning strikes, the number of each lightning strike, the location of the lightning strike, and the amplitude of the lightning current within a preset time period before and after the fault tripping time;

[0017] Background filtering is performed on the optical image of the power transmission corridor, and a threshold-adaptive edge detection algorithm is used to identify lightning discharge activity in order to verify the lightning events recorded by the lightning location system.

[0018] When the thunderstorm weather assessment is passed, the lightning location system records multiple lightning strikes, and the optical image confirms the presence of multiple discharge activities, it is determined that multiple lightning strikes have occurred in the power transmission corridor.

[0019] Furthermore, the calculation of the tower's backflashover withstand level and the dangerous lightning current range for side-strikes specifically includes:

[0020] The backflashover resistance level is calculated based on the structural parameters and grounding resistance value of the tower using electromagnetic transient simulation or standard method.

[0021] Using the electrical geometric model method, the lightning withstand level and the maximum dangerous lightning current are calculated based on the structural parameters, terrain parameters and lightning activity parameters of the tower. The lightning withstand level is used as the lower limit of the dangerous lightning current range, and the maximum dangerous lightning current is used as the upper limit of the dangerous lightning current range, thus obtaining the dangerous lightning current range.

[0022] Furthermore, the step of determining, one by one, whether there is a target lightning strike that could cause the tower to trip due to backflashover or bypass based on the lightning current amplitude corresponding to each of the aforementioned numbers, specifically includes:

[0023] The lightning current amplitude corresponding to each of the aforementioned numbers is compared with the backflash lightning withstand level. If the lightning current amplitude is greater than the backflash lightning withstand level, it is determined that the lightning strike can trigger a lightning backflash trip.

[0024] Determine whether the lightning current amplitude corresponding to each of the aforementioned numbers falls within the lightning current range of the lightning strike danger zone. If it does, determine that the lightning strike has the possibility of tripping due to lightning strike.

[0025] If any lightning strike can trigger a backflashover trip or a bypass trip, the second determination result is set to true; otherwise, it is set to false.

[0026] Furthermore, the step of determining whether the transmission line has suffered multiple lightning strikes based on the fault recording waveform and the distributed traveling wave waveform specifically includes:

[0027] Extract the traveling wave signal corresponding to each lightning strike time from the distributed traveling wave waveform, calculate the waveform steepness, wavefront amplitude and waveform pulse width of the traveling wave signal. If the number of traveling wave signals is consistent with the number of multiple lightning strikes and the waveform characteristics of each traveling wave signal conform to the characteristics of lightning strike waveform, then it is preliminarily determined that the transmission line has suffered multiple lightning strikes.

[0028] Extract the transient components corresponding to each lightning strike time from the fault recording waveform, and analyze the transient components using wavelet transform or Fourier transform. If the number of transient components is consistent with the number of multiple lightning strikes and each transient component conforms to the transient characteristics of lightning strikes, then it is further determined that the transmission line has suffered multiple lightning strikes.

[0029] When both the traveling wave signal and the transient component confirm that the transmission line has been struck by multiple lightning strikes, the location and time of the lightning strike are calculated based on the distributed traveling wave waveform or the fault recording waveform, and the third determination result is set to true.

[0030] Furthermore, the step of verifying whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes, and fault point characteristic information specifically includes:

[0031] The phase and timing of the protection action are determined based on the relay protection action information;

[0032] The phase and time of circuit breaker tripping are determined based on the changes in the switching quantity.

[0033] The phase and time of the circuit breaker tripping are matched with the number, location and time of the lightning strike. If the match is consistent, it is preliminarily confirmed that the lightning strike caused the tripping.

[0034] The fault point feature information is analyzed using a neural network algorithm to confirm that the fault point has lightning strike fault characteristics. If confirmed, the transmission line is verified to have tripped due to lightning strike, and the fourth determination result is set to true.

[0035] A comprehensive judgment system for multiple lightning strike tripping of transmission lines, comprising:

[0036] The lightning strike determination module is used to acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of the transmission line fault trip. Based on the meteorological information, lightning location system records, and optical images of the transmission corridor, it determines whether multiple lightning strikes have occurred in the transmission corridor. If so, it numbers each lightning strike and outputs the first determination result.

[0037] The lightning resistance performance determination module is used to receive the first determination result, determine the tower closest to the lightning strike location based on the first determination result, obtain the structural parameters, terrain parameters and lightning activity parameters of the tower, calculate the backflash lightning resistance level and the dangerous lightning current range of the tower, and determine whether there is a target lightning strike that can cause the tower to trip due to backflash or lightning strike based on the lightning current amplitude of each lightning strike corresponding to each number, and output the second determination result.

[0038] The waveform analysis and judgment module is used to acquire the fault recording waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment, determine whether the transmission line has suffered multiple lightning strikes based on the fault recording waveform and distributed traveling wave waveform, and calculate the lightning strike location and lightning strike time when multiple lightning strikes occur, and output the third judgment result.

[0039] The trip verification module is used to acquire relay protection action information, switch quantity changes and fault point characteristic information, and to verify whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes and fault point characteristic information, and output a fourth judgment result.

[0040] The comprehensive judgment module is used to perform a logical AND operation on the first judgment result, the second judgment result, the third judgment result and the fourth judgment result to obtain a comprehensive judgment result. When the comprehensive judgment result is true, it is determined that the transmission line has tripped due to multiple lightning strikes.

[0041] Furthermore, the lightning strike determination module includes:

[0042] The meteorological analysis unit is used to determine whether the time of the fault trip is during thunderstorms based on the weather type, temperature, humidity and warning level in the meteorological information.

[0043] The lightning location analysis unit is used to analyze the records of the lightning location system and extract the number of lightning strikes, the number of each lightning strike, the location of the lightning strike, and the amplitude of the lightning current within a preset time period before and after the fault tripping time.

[0044] An optical image analysis unit is used to perform background filtering on the optical image of the power transmission corridor and to use a threshold-adaptive edge detection algorithm to identify lightning discharge activities in order to verify the lightning events recorded by the lightning location system.

[0045] The lightning strike determination unit is connected to the meteorological analysis unit, the lightning location analysis unit, and the optical image analysis unit, respectively. It is used to determine that multiple lightning strikes have occurred in the power transmission corridor when the thunderstorm weather judgment is passed, the lightning location system records multiple lightning strikes, and the optical image confirms the existence of multiple discharge activities.

[0046] Furthermore, the lightning resistance performance determination module includes:

[0047] The backflashover lightning resistance calculation unit is used to calculate the backflashover lightning resistance level of the tower based on the structural parameters and grounding resistance value of the tower using electromagnetic transient simulation or standard method.

[0048] The lightning strike dangerous current calculation unit is used to calculate the lightning strike withstand level and the maximum dangerous lightning current based on the structural parameters, terrain parameters and lightning activity parameters of the tower using the electrical geometric model method. The lightning strike withstand level is used as the lower limit of the lightning strike dangerous current range, and the maximum dangerous lightning current is used as the upper limit of the lightning strike dangerous current range, so as to obtain the lightning strike dangerous current range.

[0049] The lightning strike impact judgment unit is connected to both the backflashover withstand calculation unit and the lightning strike hazard current calculation unit. It compares the lightning current amplitude of each lightning strike corresponding to each of the aforementioned numbers with the backflashover withstand level. If the lightning current amplitude is greater than the backflashover withstand level, it determines that the lightning strike can trigger a lightning backflashover trip. It also determines whether the lightning current amplitude of each lightning strike corresponding to each of the aforementioned numbers falls within the lightning strike hazard current range. If it does, it determines that the lightning strike has the potential for a lightning strike hazard trip. When any lightning strike can trigger a backflashover trip or a lightning strike hazard trip, the second judgment result is set to true.

[0050] Furthermore, the waveform analysis and determination module includes:

[0051] The traveling wave analysis unit is used to extract the traveling wave signal corresponding to each lightning strike time from the distributed traveling wave waveform, calculate the waveform steepness, wavefront amplitude and waveform pulse width of the traveling wave signal. If the number of traveling wave signals is consistent with the number of multiple lightning strikes and the waveform characteristics of each traveling wave signal are consistent with the characteristics of lightning strike waveform, it is preliminarily determined that the transmission line has suffered multiple lightning strikes.

[0052] The waveform recording analysis unit is used to extract the transient components corresponding to each lightning strike time in the fault waveform recording, and to analyze the transient components using wavelet transform or Fourier transform. If the number of transient components is consistent with the number of multiple lightning strikes and each transient component conforms to the transient characteristics of lightning strikes, then it is further determined that the transmission line has suffered multiple lightning strikes.

[0053] The positioning calculation unit is connected to the traveling wave analysis unit and the fault recording analysis unit respectively. When the traveling wave signal and the transient component both confirm that the transmission line has been struck by multiple lightning strikes, the unit calculates the lightning strike location and the lightning strike time based on the distributed traveling wave waveform or the fault recording waveform, and sets the third determination result to true.

[0054] An electronic device is characterized by comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the comprehensive determination method for multiple lightning strike tripping of transmission lines as described above.

[0055] A non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements the comprehensive judgment method for multiple lightning strike tripping of transmission lines as described above.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] (1) Significantly improved timeliness: Existing judgment processes mostly adopt post-event manual verification or offline waveform comparison analysis, which takes hours and cannot meet the requirements of millisecond-level rapid response to faults. This invention relies on the multi-dimensional information automatically collected by the system for real-time analysis. From the occurrence of the fault to the output of the judgment result, it can be completed in seconds (usually within 5 seconds), which can meet the requirements of rapid response of the power grid.

[0058] (2) Significantly Improved Accuracy: Existing single criteria are insufficient to effectively eliminate interfering factors, easily leading to misjudgments or omissions. This invention not only relies on electrical information but also integrates multi-dimensional information such as meteorological information of the transmission corridor area at the time of the fault, lightning location system information, optical images, automatic calculation of tower lightning resistance performance, waveform analysis, relay protection information, and fault point characteristics. Through a four-step comprehensive judgment, interfering factors are effectively eliminated, significantly improving the accuracy of the judgment. Theoretical analysis and experimental verification show that the accuracy of this invention in identifying multiple lightning strike trips is significantly better than that of single information source methods.

[0059] (3) Wide range of applications: This invention can be applied to transmission lines of different voltage levels (110kV and above), and is not limited by terrain or climate conditions, and has good generalization ability. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the overall process of the method for determining multiple lightning strike tripping of transmission lines according to the present invention.

[0061] Figure 2 This is a flowchart of the multiple lightning strike determination process for power transmission corridors according to the present invention.

[0062] Figure 3 This is a flowchart for calculating the lightning resistance performance of towers and determining the probability of lightning tripping, as per the present invention.

[0063] Figure 4 This is a flowchart for the waveform analysis and determination of multiple lightning strikes in the circuit according to the present invention.

[0064] Figure 5 This is a schematic diagram of the traveling wave waveform when the circuit of the present invention is subjected to multiple lightning strikes.

[0065] Figure 6 This is a schematic diagram of the fault waveform recorded when the line of the present invention is subjected to multiple lightning strikes.

[0066] Figure 7 This is a flowchart of the line lightning trip verification process for the present invention. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] Example 1: A comprehensive judgment method for multiple lightning strikes tripping of transmission lines

[0069] like Figure 1 As shown in the figure, this invention provides a comprehensive method for determining multiple lightning strike trips in transmission lines. This method integrates multi-dimensional information such as meteorological data, lightning location data, optical images, tower lightning withstand performance, fault recordings, traveling wave waveforms, relay protection data, and fault point characteristics to achieve rapid and accurate determination of multiple lightning strike trips in transmission lines. The method includes the following steps:

[0070] Step S1: Determination of Multiple Lightning Strikes in the Transmission Corridor

[0071] Acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of transmission line fault tripping.

[0072] like Figure 2 As shown, specifically, when a transmission line trips, the system automatically records the tripping time (for example, the tripping time of phase B of a certain line is 05:29:25:127). First, the system reads the meteorological information x1 at that time from the meteorological monitoring platform, including parameters such as weather type (e.g., heavy rain), temperature and humidity, and orange rainstorm warning level. Based on the meteorological information x1, it determines whether the fault tripping time is during thunderstorm weather—if the weather type is thunderstorm, rainstorm, or accompanied by a lightning warning, it is determined to be thunderstorm weather, and the subsequent judgment process is allowed; otherwise, it can be directly determined to be a non-lightning strike fault, and the subsequent multiple lightning strike judgment is terminated.

[0073] Secondly, the lightning location system records x2 before and after the fault tripping time are read from the lightning location system (such as the State Grid lightning location system). Preferably, the preset time period can be set to 500ms before and after the tripping time, which covers the continuous return stroke time interval of typical multiple lightning strikes (usually tens to hundreds of milliseconds). The lightning location system records x2 are analyzed to extract the number of lightning strikes, the number of each lightning strike, the lightning strike location, and the lightning current amplitude within this time period. If there are more than two lightning strikes, it is preliminarily determined that multiple lightning strikes have occurred. For example, in a certain case, the lightning location system recorded four lightning strikes, with the main discharge numbered ① and the subsequent three return strokes numbered ② to ④. The tripping time corresponds to the lightning strike numbered ③, and the lightning strike location is near tower #97.

[0074] Next, three optical images of the transmission corridor are read. These images are captured by lightning optical monitoring devices (such as high-speed cameras or lightning detectors) deployed along the transmission line corridor. Background filtering is performed on the optical images of the transmission corridor: static backgrounds are removed using frame differencing or background subtraction methods, and dynamically changing areas are extracted. Then, a threshold-adaptive edge detection algorithm (such as the Canny algorithm combined with Otsu adaptive thresholding) is used to identify the edge features of the lightning discharge activity to verify whether each lightning strike recorded by the lightning location system has a corresponding discharge trace in the optical image. When the optical image confirms the existence of discharge activity consistent with the number recorded by the lightning location system, the optical verification of multiple lightning strikes is successful.

[0075] Finally, when the thunderstorm weather assessment is passed, the lightning location system records multiple lightning strikes, and the optical image confirms multiple discharge activities, it is determined that multiple lightning strikes have occurred in the transmission corridor. Each lightning strike is numbered (e.g., ①, ②, ③, ④...), and the first determination result y1 is output. In a preferred embodiment, y1 is a Boolean variable; when multiple lightning strikes occur in the transmission corridor, y1 = 1 (true); otherwise, y1 = 0 (false).

[0076] Step S2: Calculation of tower lightning resistance performance and determination of the probability of lightning tripping

[0077] like Figure 3 As shown, based on the first determination result y1, the tower closest to the lightning strike location is determined, and the structural parameters, terrain parameters, and lightning activity parameters of the tower are obtained. The backflash lightning withstand level and the dangerous lightning current range of the tower are calculated. Based on the lightning current amplitude of each lightning strike, it is determined whether there is a target lightning strike that can cause the tower to trip due to backflash or lightning strike, and the second determination result y2 is output.

[0078] When y1=0, this step is unnecessary, and it is directly determined that there is no risk of multiple lightning strikes causing a trip. When y1=1, based on the lightning location information recorded by the lightning location system in step S1, determine the tower number closest to each lightning strike point (e.g., tower #97). Read the tower's structural parameters x4 (including tower type, tower height, crossarm structure, insulator string type and number of pieces, grounding resistance value, etc.), the terrain parameters x5 of its location (including ground inclination angle, terrain type such as mountain / plain / hill, etc.), and the lightning activity parameters x6 (including the average annual lightning strike density and probability distribution of lightning current amplitude in the area, etc.).

[0079] Calculate the backflashover withstand level: Use electromagnetic transient simulation (e.g., establish a tower-line-insulator flashover model based on ATP-EMTP software, input lightning currents of different amplitudes successively, observe whether the voltage across the insulator exceeds its 50% impulse flashover voltage U50%, and record the lightning current amplitude that just causes flashover as the backflashover withstand level) or the standard method (calculate according to the empirical formulas in DL / T 620-2019 "Overvoltage Protection and Insulation Coordination of AC Electrical Installations") to calculate the backflashover withstand level I based on the tower's structural parameters and grounding resistance value. 反击 .

[0080] Calculation of the dangerous lightning current range for backflashover: Using the Electro-Geometric Model (EGM) method, based on the structural parameters of the tower (such as conductor height and lightning conductor height), terrain parameters (ground inclination), and lightning activity parameters, the lightning withstand level I for backflashover is calculated. 绕击 (Minimum lightning current amplitude required to cause conductor flashover) and maximum dangerous lightning current I max (The maximum lightning current amplitude that causes the lightning current to bypass the lightning protection wire and directly strike the conductor). Based on the aforementioned lightning withstand level I... 绕击 As the lower limit of the dangerous lightning current range, the maximum dangerous lightning current I is used. max As the upper limit of the dangerous lightning current range, the dangerous lightning current range [I] is obtained. 绕击 , I max ].

[0081] Then, based on the lightning current amplitude I corresponding to each lightning strike number in step S1... i (i=1,2,…,n), check each one one by one:

[0082] The amplitude of the lightning current I for each lightning strike i With counter-attack against lightning level I 反击 Compare, if I i >I 反击 If the lightning strike can trigger a backflashover trip, then it is determined that the lightning strike could cause a power outage; simultaneously, it is determined that I... i Whether it falls within the aforementioned dangerous lightning current range [I] 绕击 , Imax ], if I 绕击 ,≤I i ≤ I max If so, it is determined that the lightning strike has the potential to cause a power outage due to lightning strike.

[0083] When any lightning strike meets the conditions for triggering a backflashover trip or a bypass trip, it indicates that there is a target lightning strike that can cause the tower to trip. The second determination result y2 is set to true (1), otherwise it is set to false (0). For example, if the lightning current amplitude of the lightning strike numbered ③ is 120kA, the backflashover withstand level of tower #97 is 100kA, and the bypass strike danger current range is [15kA, 80kA], then the lightning current is greater than the backflashover withstand level, and y2=1.

[0084] Step S3: Analysis and Determination of Waveforms from Multiple Lightning Strikes on the Line

[0085] like Figure 4 As shown, the fault waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment are obtained. Based on the fault waveform and distributed traveling wave waveform, it is determined whether the transmission line has suffered multiple lightning strikes. When multiple lightning strikes occur, the location and time of the lightning strikes are calculated, and the third determination result y3 is output.

[0086] Read the three-phase voltage and current waveforms before and after the tripping moment (e.g., 500ms before to 500ms after) from a fault recording device (such as a fault recorder); read the traveling wave waveforms of the fault phase before and after the tripping moment from a distributed traveling wave ranging device (such as traveling wave acquisition units arranged along the line).

[0087] First, traveling wave analysis is performed: The traveling wave signals corresponding to each lightning strike time (times corresponding to numbers ①~④) in step S1 are extracted from the distributed traveling wave waveform. The waveform steepness (i.e., the slope of the rising edge of the wavefront, dI / dt or dU / dt), wavefront amplitude (waveform peak value), and waveform pulse width (half-peak width) of each traveling wave signal segment are calculated. If the number of extracted traveling wave signals is consistent with the number of multiple lightning strikes (e.g., all 4 times), and the waveform steepness of each traveling wave signal is within the typical range of lightning traveling waves (e.g., several kA / μs to tens of kA / μs), the wavefront amplitude is within a reasonable range, and the waveform pulse width is within the range of several μs to tens of μs, then based on a comprehensive judgment, the waveform characteristics conform to the characteristics of lightning strike waveforms. Therefore, it is preliminarily determined that the transmission line has suffered multiple lightning strikes, and the traveling wave waveforms of the 4 lightning strikes are as follows: Figure 5 As shown.

[0088] Simultaneously, fault location is performed based on the distributed traveling wave waveform: the distance from the lightning strike point to both ends of the line is calculated using either the double-ended or single-ended traveling wave ranging method. If the location results from multiple traveling wave signals are all near the same tower (e.g., within ±200m of tower #97), then the location consistency verification is passed.

[0089] Next, waveform analysis is performed: transient components corresponding to each lightning strike moment are extracted from the fault waveform. Specifically, wavelet transform (such as Daubechies wavelet basis, decomposition level 4-6) or Fourier transform (short-time Fourier transform) is used to perform time-frequency decomposition on the fault phase current or voltage signal to extract high-frequency transient components (such as components with frequencies in the range of hundreds of Hz to several kHz). If transient components that meet the transient characteristics of lightning strikes (amplitude abrupt change, rich frequency components, damped oscillation) can be extracted at each lightning strike moment, and the number of transient components is consistent with the number of multiple lightning strikes, then it is further determined that the transmission line has suffered multiple lightning strikes. The fault waveform of 4 lightning strikes is as follows: Figure 6 As shown.

[0090] When both the traveling wave analysis result and the recorded wave analysis result confirm that the transmission line has suffered multiple lightning strikes, that is, the number of traveling wave signals and transient components are consistent with the number of multiple lightning strikes and the waveform characteristics are consistent with the lightning strike characteristics, the accurate lightning strike location and lightning strike time can be calculated based on the distributed traveling wave waveform or the fault recorded wave waveform (the arrival time of the first traveling wave or the start time of the transient component can be recorded as the lightning strike time), and the third judgment result y3 is set to true (1), otherwise it is set to false (0).

[0091] Step S4: Line Lightning Trip Verification

[0092] like Figure 7 As shown, the relay protection action information, switch quantity changes and fault point characteristic information are obtained. Based on the relay protection action information, switch quantity changes and fault point characteristic information, it is verified whether the transmission line has tripped due to lightning strike, and the fourth judgment result y4 is output.

[0093] Read relay protection action information before and after a fault occurs (e.g., within 5 seconds before or after the tripping moment) from the relay protection device (e.g., the phase of the action (e.g., phase A, phase B, phase C, or phase-to-phase fault) and the time of action; read the changes in switching quantities from the auxiliary contacts or intelligent terminal of the circuit breaker to determine the phase and time of the circuit breaker tripping.

[0094] The phase and time of the circuit breaker tripping are matched with the lightning strike location and time obtained in step S3, and the target lightning strike number in step S1: If the tripping phase is consistent with the lightning fault phase (e.g., both are phase B), the difference between the tripping time and the lightning strike time is within the allowable range of the circuit breaker's operating delay (e.g., 20ms~100ms), and the lightning strike number corresponding to the tripping time is consistent with the target lightning strike number determined in step S2 that could cause the tripping (e.g., number ③), then it is preliminarily confirmed that the lightning strike caused the tripping.

[0095] Further verification of the fault nature: Extract fault point feature information from optical images of faulty towers captured by on-site online monitoring devices (such as tower image monitoring devices) or UAV inspections. Analyze the fault point feature information using a pre-trained neural network classifier (such as a lightning fault identification model based on convolutional neural networks (CNN), with training samples covering typical fault images such as lightning flashover, pollution flashover, and external force damage) to extract typical lightning fault features such as lightning ablation marks, flashover channel imprints, and discharge spots on the insulator surface. If the classification confidence score output by the neural network exceeds a preset threshold (such as 0.8), it is confirmed that the fault point has lightning fault characteristics, verifying that the transmission line has tripped due to lightning, and setting the fourth judgment result y4 as true (1), otherwise setting it as false (0).

[0096] Step S5: Comprehensive Judgment

[0097] A logical AND operation is performed on the first judgment result y1, the second judgment result y2, the third judgment result y3, and the fourth judgment result y4 to obtain the comprehensive judgment result y, i.e., y = y1 ∩ y2 ∩ y3 ∩ y4. In specific implementation, this is implemented using Boolean algebra. y = 1 if and only if y1, y2, y3, and y4 are all 1 (true), and the comprehensive judgment indicates that the transmission line has tripped due to multiple lightning strikes; otherwise, y = 0, and the judgment is that the tripping due to multiple lightning strikes is not valid, i.e., the line tripping was not caused by multiple lightning strikes.

[0098] As an alternative, the first judgment result y1 to the fourth judgment result y4 can also be replaced with probability values ​​(each module outputs the probabilities p1, p2, p3, and p4 of the line tripping due to multiple lightning strikes, with values ​​ranging from 0 to 1). The final probability P = p1 × p2 × p3 × p4 (or P = Σwi·pi, where wi is the weight coefficient of each dimension) is calculated by combining the judgment results y using a product or weighted average method. A probability threshold is set (e.g., 0.7). When P is greater than this threshold, it is judged as a tripping due to multiple lightning strikes; otherwise, it is judged as a tripping due to non-multiple lightning strikes. This probability substitution scheme is an equivalent transformation within the scope of this invention.

[0099] Example 2: A Comprehensive Judgment System for Multiple Lightning Strike Trips in Transmission Lines

[0100] This embodiment provides a comprehensive judgment system for multiple lightning strike tripping of transmission lines to perform the above method. The system can be deployed in a distributed architecture, including a data acquisition layer, a data processing layer and a comprehensive decision-making layer. Each module can be connected to communicate via industrial Ethernet or high-speed data bus.

[0101] The system includes a lightning strike determination module, a lightning withstand performance determination module, a waveform analysis determination module, a trip verification module, and a comprehensive determination module. The comprehensive determination module is connected to the lightning strike determination module, lightning withstand performance determination module, waveform analysis determination module, and trip verification module via data interfaces, and is used to receive the determination results output by each module and perform comprehensive logical operations.

[0102] The lightning strike determination module is used to acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of the transmission line fault trip. Based on the meteorological information, lightning location system records, and optical images of the transmission corridor, it determines whether multiple lightning strikes have occurred in the transmission corridor. If so, it numbers each lightning strike and outputs the first determination result.

[0103] Specifically, the lightning strike determination module includes a meteorological analysis unit, a lightning location analysis unit, an optical image analysis unit, and a lightning strike determination unit.

[0104] The meteorological analysis unit connects to the power grid meteorological information platform via a data interface, reads meteorological data messages at the time of tripping in real time, and parses fields such as weather type (e.g., heavy rain, thunderstorm), temperature and humidity, and warning level. The unit has built-in judgment logic: when the weather type field contains any of the keywords "thunderstorm," "thunderstorm," or "heavy rain" and the warning level reaches orange or above, it outputs a "thunderstorm weather" flag as true.

[0105] The lightning location analysis unit connects to the lightning location system server via a dedicated communication protocol (such as IEC 61850 or DL / T 634.5104), sends query request messages (including the tripping time and a 500ms time window before and after), and receives the returned list of lightning strike events. It parses the list, including the lightning strike number (a unique identifier automatically assigned by the lightning location system), lightning strike location (latitude and longitude coordinates), lightning current amplitude (kA), polarity, and return stroke order, storing these fields in a local cache for subsequent module use.

[0106] The optical image analysis unit connects to multiple lightning optical monitoring devices deployed along the power transmission corridor via fiber optic or wireless network, receiving image sequences (frame rate no less than 1000fps) before and after the triggering moment. This unit incorporates an image preprocessing subunit and an edge detection subunit: the preprocessing subunit uses a Gaussian mixture background modeling method for background filtering to separate the moving foreground; the edge detection subunit uses the Canny edge detection algorithm (with high and low thresholds set to 200 and 100 respectively, or an Otsu adaptive threshold) to extract edges from the foreground image and detect the presence of light spot edges along the lightning discharge path. When the number and timing of the detected discharge traces match the results from the lightning location analysis unit, an optical verification flag is output as true.

[0107] The lightning strike determination unit is connected to the meteorological analysis unit, the lightning location analysis unit, and the optical image analysis unit, respectively, and receives the determination flags from the above three units. When the "thunderstorm weather" flag is true, the number of lightning strikes extracted by the lightning location analysis unit is ≥2, and the optical verification flag is true, the unit determines that multiple lightning strikes have occurred in the transmission corridor. It renumbers each lightning strike according to the numbering order recorded by the lightning location system (①, ②, ③...), constructs a data structure containing the number, time, location, and current amplitude, and packages and outputs the first determination result y1 (Boolean value and an accompanying list of lightning strike data).

[0108] The lightning resistance performance determination module is connected to the lightning strike determination module. It is used to receive the first determination result, determine the tower closest to the lightning strike location based on the first determination result, obtain the structural parameters, terrain parameters and lightning activity parameters of the tower, calculate the backflash lightning resistance level and the dangerous lightning current range of the tower, and determine whether there is a target lightning strike that can cause the tower to trip due to backflash or lightning strike based on the lightning current amplitude of each lightning strike corresponding to each number, and output the second determination result.

[0109] The lightning resistance performance determination module includes a backflash lightning resistance calculation unit, a lightning strike dangerous current calculation unit, and a lightning strike impact determination unit.

[0110] The backflashover lightning withstand calculation unit embeds a tower parameter database (storing tower type, tower height, crossarm dimensions, insulator type and number of sections, measured grounding resistance, etc.). Upon receiving the coordinates of the lightning strike location, it retrieves the nearest tower number and its parameters through spatial query. This unit employs an electromagnetic transient simulation calculation engine based on ATP-EMTP to establish an equivalent circuit model of lightning current injection into the top of the tower (including tower surge impedance model, insulator string flashover model, and grounding resistance nonlinear model). Starting from a low amplitude, the injected lightning current amplitude is gradually increased. Each simulation calculates the peak overvoltage across the insulator string. The lightning current amplitude corresponding to the first time this peak exceeds the insulator string's U50% flashover voltage (determined by the insulator type and number of sections) is defined as the backflashover withstand level I. 反击 .

[0111] The calculation unit for the dangerous current of backflashover uses the electrical geometric model method. Based on the structural parameters of the tower (such as conductor height and lightning conductor height), terrain parameters (ground inclination), and lightning activity parameters, it calculates the lightning withstand level I for backflashover. 绕击 (Minimum lightning current amplitude required to cause conductor flashover) and maximum dangerous lightning current I max (The maximum lightning current amplitude that causes the lightning current to bypass the lightning conductor and strike the ground directly). Based on the aforementioned lightning withstand level I... 绕击 As the lower limit of the dangerous lightning current range, the maximum dangerous lightning current I is used. max As the upper limit of the dangerous lightning current range, the dangerous lightning current range [I] is obtained. 绕击 ,I max ].

[0112] The lightning strike impact assessment unit is connected to the backflashover withstand current calculation unit and the flashover hazard current calculation unit, respectively, and receives I 反击 and the dangerous lightning current zone [I] 绕击 , I max The calculation results are as follows. This unit reads the lightning current amplitude I for each lightning strike output by the lightning strike determination module. i Execute in sequence: ① Compare I i >I 反击 Whether it is true or not; ② Determine I 绕击 ,≤I i ≤I max Whether it is true or false. When any condition is true, record the lightning strike number as "target lightning strike" and set the second judgment result y2 as true (1), otherwise set it as false (0).

[0113] The waveform analysis and determination module is used to acquire the fault recording waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment, determine whether the transmission line has suffered multiple lightning strikes based on the fault recording waveform and distributed traveling wave waveform, and calculate the lightning strike location and lightning strike time when multiple lightning strikes occur, and output the third determination result.

[0114] The waveform analysis and determination module includes a traveling wave analysis unit, a waveform recording analysis unit, and a positioning calculation unit.

[0115] The traveling wave analysis unit connects to the distributed traveling wave ranging device via a high-speed data acquisition card, with a sampling rate of no less than 1MHz and a time synchronization accuracy better than 1μs (achieved through GPS or BeiDou time synchronization). After a trip is triggered, the unit reads the traveling wave waveform data of the fault phase from 500ms before to 500ms after the trip time from the ring buffer. Then, taking each lightning strike time (numbered ①~④) output by the lightning strike determination module as the center, it extracts waveform segments 50μs before and after each time, and calculates the waveform steepness (the slope of the rising edge of the wavefront fitted using the least squares method), wavefront amplitude (the difference between the maximum waveform value and the baseline value), and waveform pulse width (the time width corresponding to the wavefront amplitude dropping to 50%) for each segment. The calculation results are matched with a preset lightning traveling wave characteristic template (steepness 5~50kA / μs, pulse width 2~20μs). If the number of matches matches the number of lightning strikes, the traveling wave determination flag is output as true.

[0116] The waveform analysis unit connects to the fault waveform recorder via the IEC 61850-9-2 sampling protocol to acquire three-phase current / voltage waveform data (sampling rate not less than 4kHz) for 500ms before and after the tripping moment. This unit incorporates a wavelet transform analysis subunit, using a db4 wavelet basis to perform a 5-level decomposition of the fault phase current signal, extracting detail coefficients from levels d1 to d5 as transient components. At each lightning strike moment, it checks for a sudden peak in transient components (amplitude exceeding three times the average amplitude of the previous 20ms) within the vicinity of that moment. If transient components meeting the criteria exist at all lightning strike moments, and the number of transient components matches the number of lightning strikes, then the waveform judgment flag is output as true.

[0117] The positioning calculation unit is connected to both the traveling wave analysis unit and the recording wave analysis unit, receiving the traveling wave determination flag and the recording wave determination flag. When both are true, the unit activates the positioning calculation: using the dual-end traveling wave ranging method, it calculates the lightning strike location using the time difference Δt between the two ends of the traveling wave arriving at the line (reading the wavefront arrival time from the traveling wave waveform) and the traveling wave velocity v, and averages the first traveling wavefront arrival time or the transient component start time as the lightning strike time. The output includes a third determination result y3 (Boolean value and auxiliary positioning data) containing the lightning strike location and lightning strike time.

[0118] The trip verification module is used to acquire relay protection action information, switch quantity changes and fault point characteristic information, and to verify whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes and fault point characteristic information, and outputs a fourth judgment result.

[0119] This module connects to relay protection devices and circuit breaker smart terminals via the station control layer network (MMS protocol), receives protection action events and circuit breaker position change events from GOOSE messages, and parses out the action phase and timing, tripping phase and timing. Simultaneously, this module accesses on-site online monitoring devices or drone inspection systems via wireless communication interfaces (such as 4G / 5G) to obtain high-definition images of faulty towers.

[0120] This module incorporates a built-in neural network for lightning strike fault identification, employing a pre-trained ResNet-50 convolutional neural network classifier. The input is a cropped image of the faulty tower insulator region (224×224 pixels), and the output is a probability value for "lightning strike fault." The network is pre-trained using 10,000 labeled samples covering categories such as lightning flashover, pollution flashover, bird damage, and external force damage, achieving a classification accuracy of over 92% on the test set.

[0121] The matching verification logic of this module is as follows: First, compare whether the jump-off phase is consistent with the target lightning strike phase determined by the lightning strike judgment, and compare whether the difference between the jump-off time and the lightning strike time output by the positioning calculation unit is within the preset action delay range (e.g., 20ms~100ms); Second, compare the "lightning strike failure" probability value output by the neural network with the preset threshold (e.g., 0.8). When the matching verification is passed and the probability value exceeds the threshold, the fourth judgment result y4 is output as true (1), otherwise it is false (0).

[0122] The comprehensive judgment module is connected to the lightning strike judgment module, lightning resistance performance judgment module, waveform analysis judgment module and trip verification module respectively. It is used to perform a logical AND operation on the first judgment result y1, the second judgment result y2, the third judgment result y3 and the fourth judgment result y4 to obtain the comprehensive judgment result y. When the comprehensive judgment result is true, it is determined that the transmission line has tripped due to multiple lightning strikes.

[0123] The core of this module is a logic AND gate (implemented as a bitwise AND operation in a digital processor). The inputs are four Boolean values ​​y1~y4, and the output is y = y1 ∩ y2 ∩ y3 ∩ y4. When y=1, the integrated judgment module sends a "multiple lightning strike trip" alarm signal to the dispatch automation system (including key information such as the target lightning strike number, lightning strike location, and trip phase), and simultaneously stores it in the historical event database for post-event analysis. When y=0, it outputs either "non-multiple lightning strike trip" or "judgment failed," prompting maintenance personnel to further investigate other fault types (such as operational overvoltage, wind-induced discharge, etc.).

[0124] After the system starts up, all modules are in standby mode, and the lightning strike judgment module continuously monitors the tripping event signal. When a line tripping trigger signal is detected, the above modules are woken up in sequence according to the data flow direction: the lightning strike judgment module first completes the multiple lightning strike judgment and outputs y1; if y1=1, the lightning resistance performance judgment module automatically receives the lightning strike data list and performs calculations; the waveform analysis judgment module and the tripping verification module process their respective data sources in parallel; after all modules complete the calculations, they send y1~y4 to the comprehensive judgment module, which outputs the final judgment result within seconds (usually within 5 seconds) after the tripping occurs, meeting the actual needs of the power grid for rapid fault response.

[0125] Those skilled in the art should understand that the specific algorithms involved in the above modules (such as electromagnetic transient simulation method, procedural method, electrical geometric model method, wavelet transform, Fourier transform, neural network, etc.) can all be replaced with other equivalent algorithms known in the art, as long as the same calculation or discrimination purpose is achieved. Meanwhile, the order of the four-step judgment process is not strictly fixed. For example, steps S3 and S4 can be executed in parallel to improve processing speed, or step S2 can be executed before step S1 (i.e., pre-calculating the lightning resistance level of each tower). These adjustments do not change the overall discrimination concept of the present invention and are all within the protection scope of the present invention. The alternative scheme of using probability representation (instead of Boolean values) for the first to fourth judgment results has been detailed in step S5 of Embodiment 1. The corresponding modifications at the system level (changing Boolean logic AND to a probability multiplier or weighted summer) are also equivalent transformations of the present invention and will not be elaborated here. Embodiment 3: An electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the comprehensive judgment method for multiple lightning strike tripping of transmission lines as described above.

[0126] Example 4: A non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the comprehensive judgment method for multiple lightning strike tripping of transmission lines as described above.

[0127] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0128] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0129] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0130] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for comprehensive determination of multiple lightning trip-out of a power transmission line, characterized in that, Includes the following steps: Acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of the transmission line fault trip. Based on the meteorological information, lightning location system records, and optical images of the transmission corridor, determine whether multiple lightning strikes have occurred in the transmission corridor. If so, number each lightning strike and output the first determination result. Based on the first determination result, the tower closest to the lightning strike location is determined, and the structural parameters, terrain parameters and lightning activity parameters of the tower are obtained. The backflash lightning withstand level and the dangerous lightning current range of the backflash lightning strike are calculated. Based on the lightning current amplitude of each lightning strike corresponding to each number, it is determined whether there is a target lightning strike that can cause the tower to trip due to backflash lightning strike or backflash lightning strike. The second determination result is then output. The fault waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment are obtained. Based on the fault waveform and distributed traveling wave waveform, it is determined whether the transmission line has been struck by multiple lightning strikes. When multiple lightning strikes are struck, the location and time of the lightning strike are calculated and the third determination result is output. Obtain relay protection action information, switch quantity changes and fault point characteristic information, verify whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes and fault point characteristic information, and output the fourth judgment result; A logical AND operation is performed on the first determination result, the second determination result, the third determination result, and the fourth determination result to obtain a comprehensive determination result. When the comprehensive determination result is true, it is determined that the transmission line has tripped due to multiple lightning strikes.

2. The method according to claim 1, wherein The step of determining whether multiple lightning strikes have occurred within the transmission corridor based on the meteorological information, lightning location system records, and optical images of the transmission corridor specifically includes: Based on the weather type, temperature, humidity, and warning level in the meteorological information, determine whether the time of the fault trip occurred during thunderstorms; Analyze the records of the lightning location system to extract the number of lightning strikes, the number of each lightning strike, the location of the lightning strike, and the amplitude of the lightning current within a preset time period before and after the fault tripping time; Background filtering is performed on the optical image of the power transmission corridor, and a threshold-adaptive edge detection algorithm is used to identify lightning discharge activity in order to verify the lightning events recorded by the lightning location system. When the thunderstorm weather assessment is passed, the lightning location system records multiple lightning strikes, and the optical image confirms the presence of multiple discharge activities, it is determined that multiple lightning strikes have occurred in the power transmission corridor.

3. The method according to claim 1, wherein The calculation of the backflashover withstand level and the dangerous lightning current range of the tower specifically includes: The backflashover resistance level is calculated based on the structural parameters and grounding resistance value of the tower using electromagnetic transient simulation or standard method. Using the electrical geometric model method, the lightning withstand level and the maximum dangerous lightning current are calculated based on the structural parameters, terrain parameters and lightning activity parameters of the tower. The lightning withstand level is used as the lower limit of the dangerous lightning current range, and the maximum dangerous lightning current is used as the upper limit of the dangerous lightning current range, thus obtaining the dangerous lightning current range.

4. The method of claim 1, wherein the method is characterized by: The step of determining, based on the lightning current amplitude corresponding to each of the aforementioned numbers, whether there is a target lightning strike that could cause the tower to trip due to backflashover or bypass strike, specifically includes: The lightning current amplitude corresponding to each of the aforementioned numbers is compared with the backflash lightning withstand level. If the lightning current amplitude is greater than the backflash lightning withstand level, it is determined that the lightning strike can trigger a lightning backflash trip. Determine whether the lightning current amplitude corresponding to each of the aforementioned numbers falls within the lightning current range of the lightning strike danger zone. If it does, determine that the lightning strike has the possibility of tripping due to lightning strike. If any lightning strike can trigger a backflashover trip or a bypass trip, the second determination result is set to true; otherwise, it is set to false.

5. The comprehensive judgment method for multiple lightning strike tripping of transmission lines according to claim 1, characterized in that, The step of determining whether the transmission line has suffered multiple lightning strikes based on the fault recording waveform and the distributed traveling wave waveform specifically includes: Extract the traveling wave signal corresponding to each lightning strike time from the distributed traveling wave waveform, calculate the waveform steepness, wavefront amplitude and waveform pulse width of the traveling wave signal. If the number of traveling wave signals is consistent with the number of multiple lightning strikes and the waveform characteristics of each traveling wave signal conform to the characteristics of lightning strike waveform, then it is preliminarily determined that the transmission line has suffered multiple lightning strikes. Extract the transient components corresponding to each lightning strike time from the fault recording waveform, and analyze the transient components using wavelet transform or Fourier transform. If the number of transient components is consistent with the number of multiple lightning strikes and each transient component conforms to the transient characteristics of lightning strikes, then it is further determined that the transmission line has suffered multiple lightning strikes. When both the traveling wave signal and the transient component confirm that the transmission line has been struck by multiple lightning strikes, the location and time of the lightning strike are calculated based on the distributed traveling wave waveform or the fault recording waveform, and the third determination result is set to true.

6. The comprehensive judgment method for multiple lightning strike tripping of transmission lines according to claim 1, characterized in that, The step of verifying whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes, and fault point characteristic information specifically includes: The phase and timing of the protection action are determined based on the relay protection action information; The phase and time of circuit breaker tripping are determined based on the changes in the switching quantity. The phase and time of the circuit breaker tripping are matched with the number, location and time of the lightning strike. If the match is consistent, it is preliminarily confirmed that the lightning strike caused the tripping. The fault point feature information is analyzed using a neural network algorithm to confirm that the fault point has lightning strike fault characteristics. If confirmed, the transmission line is verified to have tripped due to lightning strike, and the fourth determination result is set to true.

7. A comprehensive judgment system for multiple lightning strike tripping of transmission lines, characterized in that, include: The lightning strike determination module is used to acquire meteorological information, lightning location system records, and optical images of the transmission corridor at the time of the transmission line fault trip. Based on the meteorological information, lightning location system records, and optical images of the transmission corridor, it determines whether multiple lightning strikes have occurred in the transmission corridor. If so, it numbers each lightning strike and outputs the first determination result. The lightning resistance performance determination module is used to receive the first determination result, determine the tower closest to the lightning strike location based on the first determination result, obtain the structural parameters, terrain parameters and lightning activity parameters of the tower, calculate the backflash lightning resistance level and the dangerous lightning current range of the tower, and determine whether there is a target lightning strike that can cause the tower to trip due to backflash or lightning strike based on the lightning current amplitude of each lightning strike corresponding to each number, and output the second determination result. The waveform analysis and judgment module is used to acquire the fault recording waveform and distributed traveling wave waveform of the transmission line before and after the tripping moment, determine whether the transmission line has suffered multiple lightning strikes based on the fault recording waveform and distributed traveling wave waveform, and calculate the lightning strike location and lightning strike time when multiple lightning strikes occur, and output the third judgment result. The trip verification module is used to acquire relay protection action information, switch quantity changes and fault point characteristic information, and to verify whether the transmission line has tripped due to lightning strike based on the relay protection action information, switch quantity changes and fault point characteristic information, and output a fourth judgment result. The comprehensive judgment module is used to perform a logical AND operation on the first judgment result, the second judgment result, the third judgment result and the fourth judgment result to obtain a comprehensive judgment result. When the comprehensive judgment result is true, it is determined that the transmission line has tripped due to multiple lightning strikes.

8. The comprehensive judgment system for multiple lightning strike tripping of transmission lines according to claim 7, characterized in that, The lightning strike determination module includes: The meteorological analysis unit is used to determine whether the time of the fault trip is during thunderstorms based on the weather type, temperature, humidity and warning level in the meteorological information. The lightning location analysis unit is used to analyze the records of the lightning location system and extract the number of lightning strikes, the number of each lightning strike, the location of the lightning strike, and the amplitude of the lightning current within a preset time period before and after the fault tripping time. An optical image analysis unit is used to perform background filtering on the optical image of the power transmission corridor and to use a threshold-adaptive edge detection algorithm to identify lightning discharge activities in order to verify the lightning events recorded by the lightning location system. The lightning strike determination unit is connected to the meteorological analysis unit, the lightning location analysis unit, and the optical image analysis unit, respectively. It is used to determine that multiple lightning strikes have occurred in the power transmission corridor when the thunderstorm weather judgment is passed, the lightning location system records multiple lightning strikes, and the optical image confirms the existence of multiple discharge activities.

9. The comprehensive judgment system for multiple lightning strike tripping of transmission lines according to claim 7, characterized in that, The lightning resistance performance determination module includes: The backflashover lightning resistance calculation unit is used to calculate the backflashover lightning resistance level of the tower based on the structural parameters and grounding resistance value of the tower using electromagnetic transient simulation or standard method. The lightning strike dangerous current calculation unit is used to calculate the lightning strike withstand level and the maximum dangerous lightning current based on the structural parameters, terrain parameters and lightning activity parameters of the tower using the electrical geometric model method. The lightning strike withstand level is used as the lower limit of the lightning strike dangerous current range, and the maximum dangerous lightning current is used as the upper limit of the lightning strike dangerous current range, so as to obtain the lightning strike dangerous current range. The lightning strike impact judgment unit is connected to the backflashover withstand calculation unit and the lightning strike hazard current calculation unit, respectively. It is used to compare the lightning current amplitude of each lightning strike corresponding to each number with the backflashover withstand level. If the lightning current amplitude is greater than the backflashover withstand level, it is determined that the lightning strike can trigger a lightning backflashover trip. It is also determined whether the lightning current amplitude of each lightning strike corresponding to each number falls within the lightning strike hazard current range. If it does, it is determined that the lightning strike has the possibility of lightning strike skewing trip. When any lightning strike can trigger a backflashover trip or a lightning strike skewing trip, the second judgment result is set to true.

10. The comprehensive judgment system for multiple lightning strike tripping of transmission lines according to claim 7, characterized in that, The waveform analysis and determination module includes: The traveling wave analysis unit is used to extract the traveling wave signal corresponding to each lightning strike time from the distributed traveling wave waveform, calculate the waveform steepness, wavefront amplitude and waveform pulse width of the traveling wave signal. If the number of traveling wave signals is consistent with the number of multiple lightning strikes and the waveform characteristics of each traveling wave signal are consistent with the characteristics of lightning strike waveform, it is preliminarily determined that the transmission line has suffered multiple lightning strikes. The waveform recording analysis unit is used to extract the transient components corresponding to each lightning strike time in the fault waveform recording, and to analyze the transient components using wavelet transform or Fourier transform. If the number of transient components is consistent with the number of multiple lightning strikes and each transient component conforms to the transient characteristics of lightning strikes, then it is further determined that the transmission line has suffered multiple lightning strikes. The positioning calculation unit is connected to the traveling wave analysis unit and the fault recording analysis unit respectively. When the traveling wave signal and the transient component both confirm that the transmission line has been struck by multiple lightning strikes, the unit calculates the lightning strike location and the lightning strike time based on the distributed traveling wave waveform or the fault recording waveform, and sets the third determination result to true.

11. An electronic device, characterized in that: It includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the comprehensive judgment method for multiple lightning strike tripping of transmission lines as described in any one of claims 1-6.

12. A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the comprehensive determination method for multiple lightning strike tripping of transmission lines as described in any one of claims 1-6.

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