An ice-melting line lightning stroke type recognition method based on transient current integral characteristics and related equipment

Abstract

The application provides an ice-melting line lightning stroke type identification method based on a transient current integral characteristic and related equipment, and belongs to the technical field of lightning stroke state identification. The method comprises the following steps: acquiring a transient current sequence to be judged; the transient current sequence is derived from an ice-melting ground wire monitoring end; the transient current sequence is preprocessed to determine an analysis window for integral calculation; in the analysis window, a positive half-cycle integral is obtained according to non-negative sampling values of the transient current sequence, and a negative half-cycle absolute integral is obtained according to absolute values of negative sampling values of the transient current sequence; a double-end comprehensive feature quantity is calculated according to the positive half-cycle integral and the negative half-cycle absolute integral; the double-end comprehensive feature quantity is compared with a preset identification threshold, and a lightning stroke flashover type identification result is obtained according to a comparison result. The application can realize accurate identification of lightning direct ground wire and around strike phase conductor types without relying on lightning current absolute amplitude and large-scale training samples.

Description

Technical Field

[0001] This application relates to the field of lightning strike status identification technology, and in particular to a method and related equipment for identifying lightning strike types in de-icing lines based on transient current integral characteristics. Background Technology

[0002] In related technologies, the use of spectral transformation or training classifiers requires a large amount of computing resources or a large number of labeled samples, which is not conducive to rapid implementation in low-power processing units.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0004] The main objective of this application is to propose a method and related equipment for identifying lightning strike types on de-icing lines based on transient current integral characteristics. This method can accurately identify the types of direct lightning strikes to the ground wire and lightning strikes around the phase conductor without relying on the absolute amplitude of the lightning current and a large number of training samples.

[0005] To achieve the above objectives, one aspect of this application proposes a method for identifying lightning strike types on de-icing lines based on transient current integral characteristics. The method includes the following steps: Obtain the transient current sequence to be judged; the transient current sequence is derived from the de-icing ground wire monitoring terminal; The transient current sequence is preprocessed to determine the analysis window used for integration calculation; Within the analysis window, the positive half-cycle integral is obtained based on the non-negative sampled values ​​of the transient current sequence, and the negative half-cycle absolute integral is obtained based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. The two-end comprehensive characteristic quantity is calculated based on the positive half-cycle integral and the negative half-cycle absolute integral. The dual-end integrated feature quantity is compared with a preset identification threshold, and the lightning strike type identification result is obtained based on the comparison result.

[0006] In some embodiments, obtaining the transient current sequence to be determined includes: A first monitoring terminal is set at one end of the ice-melting ground wire or fiber optic composite overhead ground wire of the DC ice-melting transformation line, and a second monitoring terminal is set at the other end. Each monitoring terminal is equipped with a transient current sensor and a data acquisition unit to record the waveform before triggering and the waveform for a preset time period after triggering. The first monitoring terminal and the second monitoring terminal are synchronized in a unified manner, and the positive current direction is taken as the direction from the inside of the ice-melting section to the outside of the section. After a candidate lightning strike event occurs, the waveforms of the first monitoring terminal and the second monitoring terminal are paired, and the data within a preset time after the arrival of the first wave at the first monitoring terminal and the second monitoring terminal are taken as the transient current sequence to be judged.

[0007] In some embodiments, the preprocessing of the transient current sequence to determine the analysis window for integration calculation includes: The transient current sequence is baseline corrected, the mean of the data before triggering is subtracted, and then preprocessed by power frequency component filtering, low frequency drift removal and high frequency noise suppression to obtain the waveform to be analyzed. The short-term energy exceeding a preset trigger threshold is used as the candidate event triggering condition; the short-term energy is calculated by summing the squares of the amplitudes of each sampling point within a preset short-term analysis window. When the short-term energy is greater than or equal to the trigger threshold, it is determined to be triggered; when the short-term energy is less than the trigger threshold, it is determined that no event has occurred and monitoring continues. Waveform pairing is performed based on the event time of the two monitoring terminals. When both monitoring terminals are triggered within the preset pairing time window, and the waveform to be analyzed has the characteristics of a lightning strike transient steep wavefront, pairing is confirmed. A segment of continuous sampling points of a preset length after the arrival of the first transient current wave is extracted from the waveform to be analyzed after the pairing is confirmed, and used as an analysis window for integration calculation; the arrival time of the first transient current wave is determined according to the time when the amplitude of the waveform to be analyzed first exceeds a set threshold.

[0008] In some embodiments, the step of obtaining the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence and obtaining the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence within the analysis window includes: For each monitoring terminal, within the analysis window, the amplitude of the non-negative sampled value in the transient current sequence of the same monitoring terminal is multiplied and accumulated by the sampling time interval, and the accumulated result is used as the positive half-cycle integral of the monitoring terminal. The absolute value of the amplitude of the negative sampled value in the transient current sequence of the same monitoring terminal is multiplied by the sampling time interval and accumulated. The accumulated result is used as the negative half-cycle absolute integral of the monitoring terminal.

[0009] In some embodiments, calculating the two-end composite characteristic based on the positive half-cycle integral and the negative half-cycle absolute integral includes: For each monitoring terminal, the normalized integral characteristic of each monitoring terminal is calculated by taking the absolute value of the difference between the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring terminal as the numerator, and the sum of the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring terminal and a positive number as the denominator. The normalized integral feature values ​​of each monitoring terminal are arithmetically averaged to obtain the combined feature value of both terminals.

[0010] In some embodiments, comparing the dual-ended integrated feature quantity with a preset identification threshold and obtaining the lightning strike type identification result based on the comparison result includes: When the combined feature quantity of the two ends is greater than or equal to the preset identification threshold, the lightning strike type is determined to be direct lightning strike to the ground wire; When the combined feature quantity of the two ends is less than the preset identification threshold, the lightning strike type is determined to be lightning strike on the phase conductor; Output the lightning strike type identification result; the lightning strike type identification result includes the event time, the waveform number of each monitoring end, the normalized integral feature of each monitoring end, the dual-end comprehensive feature, and the lightning strike type.

[0011] To achieve the above objectives, another aspect of this application proposes a device for identifying lightning strike types on de-icing lines based on transient current integral characteristics. The device includes: A waveform input unit is used to acquire the transient current sequence to be judged; the transient current sequence originates from the de-icing ground wire monitoring terminal. A preprocessing unit is used to preprocess the transient current sequence and determine the analysis window for integration calculation; An integration calculation unit is used to obtain the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence within the analysis window, and to obtain the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. The feature quantity calculation unit is used to calculate the two-end comprehensive feature quantity based on the positive half-cycle integral and the negative half-cycle absolute integral. The threshold discrimination unit is used to compare the dual-end integrated feature quantity with the preset identification threshold, and obtain the lightning strike type identification result based on the comparison result.

[0012] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0013] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods described above.

[0014] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer program product, including a computer program that, when executed by a processor, implements the aforementioned method.

[0015] The embodiments of this application include at least the following beneficial effects: This application provides a method, device, electronic device, storage medium, and program product for identifying lightning strike types on de-icing lines based on transient current integral characteristics. The solution includes: acquiring a transient current sequence to be judged; the transient current sequence originates from the de-icing ground wire monitoring end; preprocessing the transient current sequence to determine an analysis window for integral calculation; within the analysis window, obtaining the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence, and obtaining the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence; calculating a two-end comprehensive feature quantity based on the positive half-cycle integral and the negative half-cycle absolute integral; comparing the two-end comprehensive feature quantity with a preset identification threshold, and obtaining the lightning strike type identification result based on the comparison result. This application can achieve accurate identification of direct lightning strikes to the ground wire and lightning strikes around the conductor type without relying on the absolute amplitude of the lightning current and a large number of training samples. Attached Figure Description

[0016] Figure 1 This is a flowchart of a method for identifying lightning strike types on de-icing lines based on transient current integral characteristics, provided in an embodiment of this application. Figure 2 This is a schematic diagram of a typical wiring topology for the de-icing ground wire provided in an embodiment of this application; Figure 3 This is a schematic diagram of the transient current waveforms at two monitoring points under four insulator gap states when directly hitting the OPGW, as provided in the embodiments of this application. Figure 4 This is a schematic diagram of the transient current waveforms at two monitoring points under four insulator gap states when the A-phase conductor is struck by a wire, as provided in the embodiments of this application. Figure 5 This is a flowchart of the lightning strike type identification using dual-ended integral features provided in the embodiments of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0019] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.

[0020] 1) Icing Ground Wire: This refers to the ground wire in an overhead transmission line that has undergone DC icing modification. In cold regions, ground wires (including OPGW) may experience wire breakage or tower collapse due to excessive icing in winter. DC icing technology uses an icing power source to apply DC current to the ground wire, causing it to heat up and melt the ice. In this scheme, the two ends of the icing ground wire section are clearly defined, facilitating the installation of transient current acquisition devices and providing a natural structural basis for dual-end monitoring of lightning transient currents.

[0021] 2) Two-End Integrated Characteristic: A core quantitative indicator for lightning strike type identification. Its calculation process is as follows: First, calculate the normalized integral characteristic (reflecting the difference in positive and negative half-cycle areas of the transient waveform at each monitoring end in the melting ground wire section). Then, arithmetically average the normalized integral characteristic values ​​at both ends to obtain the final single value. This characteristic value ranges from 0 to 1; the closer to 1, the stronger the waveform's unipolarity (corresponding to a direct strike to the ground wire); the closer to 0, the stronger the waveform's positive and negative symmetry (corresponding to a strike around the phase conductor). By using a two-end averaging method, the identification fluctuations caused by single-end boundary reflections, sensor noise, or channel gain deviations can be effectively reduced.

[0022] 3) OPGW: This is an abbreviation for "Optical Fiber Composite Overhead GroundWire." It is a special type of power cable that combines the functions of overhead ground wire lightning protection and optical fiber communication. Its structure contains optical fiber units at its core, with an outer conductive layer made of aluminum tubes or aluminum alloy stranded wires. In transmission lines, OPGW simultaneously performs the dual functions of electrical lightning protection (as a ground wire for lightning strikes) and power system communication (transmitting data, protection signals, etc.). In this scheme, OPGW is used as a type of de-icing ground wire, and transient current acquisition devices can be installed at both ends to capture the transient current waveform of lightning strikes.

[0023] In related technologies, DC de-icing technology typically requires insulation or segmentation of overhead ground wires to ensure they form a current loop during de-icing. In non-de-icing operation, the de-icing ground wire maintains lightning protection and communication functions through pre-set grounding points, short-circuit points, or protective gaps. Compared to conventional tower-by-tower grounding wires, de-icing ground wires feature segmented insulation, clearly defined loop boundaries, and the ability for transient currents to propagate within the ground wire channel.

[0024] When a transmission line is struck by lightning, the mechanism of transient current formation in the ground wire differs between a direct lightning strike to the ground wire and a lightning strike around a conductor in the melting ice-covered ground wire. When lightning strikes the ground wire directly, the lightning current is injected directly into the ground wire at the point of impact and propagates along the ground wire to both sides. The transient current at the monitoring point typically exhibits a waveform with a prominent dominant polarity and gradual decay. When lightning strikes a conductor, the transient current in the ground wire is mainly generated by the electromagnetic coupling between the conductor and the ground wire. The waveform at the monitoring point typically oscillates around the zero axis, with the positive and negative half-cycles being relatively close. These waveform differences provide a physical basis for identifying the type of lightning strike using the transient current in the ground wire.

[0025] Existing lightning location systems primarily rely on spatial electromagnetic field information to determine the time and location of lightning strikes, often making it difficult to directly determine whether lightning struck the ground wire or a phase conductor. Traditional phase conductor traveling wave monitoring devices mainly address tripping faults, with insufficient coverage for ground wire lightning strikes that do not cause phase insulation flashover. Methods relying on manual waveform observation depend on experience, making it difficult to generate stable and automated judgment results.

[0026] The correlation discrimination method for transient current waveforms has at least the following shortcomings: (1) When judging the type of lightning strike based solely on the peak value of transient current, the result is easily affected by the amplitude of lightning current, the location of lightning strike, propagation attenuation and sensor gain.

[0027] (2) When using several instantaneous sampling points or local extreme values ​​as criteria, noise, local reflection and waveform distortion may cause fluctuations in the criteria.

[0028] (3) When using spectrum transformation or training classifiers, more computing resources or a large number of labeled samples are required, which is not conducive to rapid implementation in low-power processing units.

[0029] Therefore, there is a need for a lightning strike type identification method that is based on the cumulative area difference of the waveform, requires less computation, has a clear criterion meaning, and can reduce the influence of absolute amplitude changes.

[0030] In view of this, this application provides a method and related equipment for identifying lightning strike types on de-icing lines based on transient current integral characteristics. This scheme can effectively distinguish between two lightning strike types—direct lightning strike to the ground wire and lightning strike around the phase conductor—by using transient current waveforms obtained from monitoring points at both ends of the de-icing ground wire and quantitatively analyzing the difference in the integral area of ​​the positive and negative half-cycles of the waveform, without relying on the absolute amplitude of the lightning current and a large number of training samples. At the same time, it suppresses single-end reflection and noise interference by fusing dual-end feature quantities, thereby improving the accuracy and reliability of identification and providing simple and efficient technical support for lightning strike fault identification and operation and maintenance decisions of DC de-icing lines.

[0031] Figure 1 This is an optional flowchart of a method for identifying lightning strike types on de-icing lines based on transient current integral characteristics, provided in an embodiment of this application. Figure 1 The method may include, but is not limited to, steps S101 to S105.

[0032] Step S101: Obtain the transient current sequence to be judged; the transient current sequence is derived from the de-icing ground wire monitoring terminal; Step S102: Preprocess the transient current sequence to determine the analysis window used for integration calculation; Step S103: Within the analysis window, obtain the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence, and obtain the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. Step S104: Calculate the two-end comprehensive characteristic quantity based on the positive half-cycle integral and the negative half-cycle absolute integral. Step S105: Compare the dual-end integrated feature quantity with the preset identification threshold, and obtain the lightning strike type identification result based on the comparison result.

[0033] Steps S101 to S105 as shown in the embodiments of this application involve collecting transient lightning current waveforms at monitoring points at both ends of the de-icing ground wire section, calculating the integral area of ​​the positive and negative half-cycles at each end and normalizing it to quantify the unipolarity or oscillation symmetry of the waveform, then merging the characteristic quantities at both ends on average, and finally comparing it with a preset threshold to achieve accurate identification of the lightning direct-strike ground wire and the winding phase conductor type without relying on the absolute amplitude of the lightning current and a large number of training samples.

[0034] In some embodiments, step S101 may include, but is not limited to, steps S111 to S112: Step S111: Set a first monitoring end at one end of the ice-melting ground wire or fiber optic composite overhead ground wire of the DC ice-melting transformation line and a second monitoring end at the other end. Install transient current sensors and data acquisition units at each monitoring end to record the waveform before triggering and the waveform during a preset time period after triggering. Use unified timing for the first and second monitoring ends and take the direction from inside the ice-melting section to outside the section as the positive direction of the current. Step S112: After a candidate lightning strike event occurs, the waveforms of the first monitoring terminal and the second monitoring terminal are paired, and the data within a preset time after the arrival of the first wave at the first monitoring terminal and the second monitoring terminal are taken as the transient current sequence to be judged.

[0035] In steps S111 to S112 of some embodiments, transient current waveforms are collected by setting monitoring terminals at both ends of the de-icing ground wire section, providing the original data basis for subsequent lightning strike type identification based on waveform morphology differences, and the dual-end acquisition mechanism provides redundant information sources for subsequent fusion discrimination.

[0036] In some embodiments, step S102 may include, but is not limited to, steps S201 to S205: Step S201: Baseline correction is performed on the transient current sequence, the mean of the data before triggering is subtracted, and then preprocessing is performed on the power frequency component filtering, low frequency drift removal and high frequency noise suppression to obtain the waveform to be analyzed. Step S202: The short-time energy exceeding the preset trigger threshold is used as the candidate event trigger condition; the short-time energy is calculated by summing the squares of the amplitudes of each sampling point within the preset short-time analysis window. Step S203: When the short-term energy is greater than or equal to the trigger threshold, it is determined to be triggered; when the short-term energy is less than the trigger threshold, it is determined to be no event and monitoring continues. Step S204: Perform waveform pairing based on the event time of the two monitoring terminals. When both monitoring terminals are triggered within the preset pairing time window and the waveform to be analyzed has the characteristics of a lightning strike transient steep wavefront, confirm the pairing. Step S205: Extract a segment of continuous sampling points of a preset length from the waveform to be analyzed after the arrival of the first wave of transient current from the confirmed pairing, as an analysis window for integration calculation; the arrival time of the first wave of transient current is determined according to the time when the amplitude of the waveform to be analyzed first exceeds the set threshold.

[0037] In steps S201 to S205 of some embodiments, noise and drift in the original signal are removed by preprocessing, and the analysis window used for integration calculation is accurately located, so that the data segment used for subsequent integration calculation has a high signal-to-noise ratio and accurately corresponds to the transient process of lightning strike.

[0038] In some embodiments, step S103 may include, but is not limited to, steps S301 to S302: Step S301: For each monitoring terminal, within the analysis window, the amplitude of the non-negative sampled value in the transient current sequence of the same monitoring terminal is multiplied and accumulated by the sampling time interval, and the accumulated result is used as the positive half-cycle integral of the monitoring terminal. Step S302: Take the absolute value of the amplitude of the negative sampled value in the transient current sequence of the same monitoring terminal and multiply it by the sampling time interval, and accumulate the result as the absolute integral of the negative half-cycle of the monitoring terminal.

[0039] In steps S301 to S302 of some embodiments, the waveform morphology difference is quantified into a numerical integral index. By accumulating the areas on both sides of the zero axis, the essential difference in the zero axis distribution of the two types of waveforms, namely, the direct ground wire (unipolar) and the winding phase conductor (oscillating symmetry), is captured, and the qualitative analysis is transformed into quantitative calculation.

[0040] In some embodiments, step S104 may include, but is not limited to, steps S401 to S402: Step S401: For each monitoring end, the normalized integral characteristic of each monitoring end is calculated by taking the absolute value of the difference between the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring end as the numerator, and the sum of the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring end and a positive number as the denominator. Step S402: The normalized integral characteristic quantities of each monitoring end are arithmetically averaged to obtain the combined characteristic quantity of both ends.

[0041] In steps S401 to S402 of some embodiments, the integration results of both ends are converted into a comprehensive feature quantity of both ends, so that the single index used for final discrimination contains information from both ends at the same time, providing a comprehensive and simplified discrimination basis for subsequent threshold comparison.

[0042] In some embodiments, step S105 may include, but is not limited to, steps S501 to S503: Step S501: When the combined feature quantity of both ends is greater than or equal to the preset identification threshold, the lightning strike type is determined to be direct lightning strike to the ground wire. Step S502: When the combined feature quantity of both ends is less than the preset identification threshold, the lightning strike type is determined to be lightning strike on the phase conductor. Step S503: Output the lightning strike type identification result; the lightning strike type identification result includes the event time, waveform number of each monitoring end, normalized integral feature of each monitoring end, dual-end comprehensive feature and lightning strike type.

[0043] In some embodiments, steps S501 to S503 are performed by threshold comparison to determine the type of lightning strike. The decision-making rules are simple and clear, requiring no complex reasoning or expert judgment, which facilitates real-time automatic identification by online monitoring devices.

[0044] This application embodiment also provides a lightning strike type identification device for de-icing lines based on transient current integral characteristics, the device comprising: The waveform input unit is used to acquire the transient current sequence to be judged; the transient current sequence is derived from the de-icing ground wire monitoring terminal. The preprocessing unit is used to preprocess the transient current sequence and determine the analysis window for integration calculation; The integration calculation unit is used to obtain the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence within the analysis window, and to obtain the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. The feature quantity calculation unit is used to calculate the two-end comprehensive feature quantity based on the positive half-cycle integral and the negative half-cycle absolute integral. The threshold discrimination unit is used to compare the dual-end comprehensive feature quantity with the preset identification threshold, and obtain the lightning strike connection type identification result based on the comparison result.

[0045] This invention relates to the fields of high voltage technology, online monitoring of overhead transmission lines, and lightning strike status identification. Specifically, it relates to a method for collecting transient lightning currents at both ends of the de-icing ground wire or optical fiber composite overhead ground wire (OPGW) of a DC de-icing retrofit line, and identifying direct lightning strikes to the ground wire and lightning strikes around the phase conductor by calculating the positive and negative half-cycle integrals and their normalized differences.

[0046] As an optional implementation, the technical problem to be solved by the present invention is: under the condition that the transient current waveform of lightning strike has been obtained, how to use the cumulative area difference of the waveform on both sides of the zero axis to identify the direct lightning strike to the ground wire and the lightning strike around the phase conductor without relying on the absolute amplitude of the lightning current and a large number of training samples.

[0047] refer to Figure 2 The schematic diagram of a typical wiring topology for the de-icing ground wire applicable to this invention illustrates the relationship between OPGW, ordinary ground wire, de-icing power supply, disconnect switch, connecting wire, grounding point and de-icing section.

[0048] This invention provides a method for identifying lightning strike types on ice-melting lines based on the integral characteristics of transient current in the ground wire at both ends (a method for identifying lightning strike types on ice-melting lines based on the integral characteristics of transient current). This method is applicable to overhead transmission lines with clearly defined ice-melting zone boundaries. Transient current acquisition devices are installed at both ends of the ice-melting ground wire zone to obtain the transient current waveforms of the ground wire at the two monitoring ends for the same lightning strike event. The method includes the following steps.

[0049] (1) Obtain the waveform of the transient current to be judged: Obtain the transient current sequence to be judged from existing lightning monitoring devices, data acquisition units, or waveform databases. j (k), where j is the monitoring channel number and k is the discrete sampling point number. The waveform should include the transient process of the lightning strike and its preceding baseline data.

[0050] In one implementation, the transient current sequence is derived from the de-icing ground wire monitoring channel; when multiple monitoring channels exist, the waveforms of each channel are input into this method and the identification results are obtained independently, and each identification result is determined only by the positive and negative half-cycle integral characteristics of the corresponding channel.

[0051] refer to Figure 3 The present invention identifies typical transient current waveforms of OPGW in the target object, showing transient current waveforms at two monitoring points under four typical states of ground wire insulator gap.

[0052] refer to Figure 4 The present invention identifies typical transient current waveforms of the A-phase conductor in the object of the invention, and shows the transient current waveforms at two monitoring points under four typical states of the ground wire insulator gap.

[0053] (2) Waveform preprocessing and analysis window determination: The acquired waveform is subjected to baseline correction, power frequency component filtering, low-frequency drift removal, and high-frequency noise suppression to obtain the waveform to be analyzed. ,in The monitoring points are numbered. Short-term energy exceeding the trigger threshold is used as the candidate event triggering condition, and waveforms are paired based on the event times at both ends.

[0054] Short-time energy is calculated according to formula (1): (1) In the formula, For the first Discrete sampling waveforms at each monitoring point For short-time analysis window length, This is the starting sampling point for the window. If both monitoring ends trigger within the preset pairing time window and the waveform has the characteristics of a lightning strike transient steep wavehead, then proceed to the subsequent type identification; if only one end experiences an isolated low-energy trigger, or the event times at both ends cannot be paired, then it is marked as external interference or an event to be verified.

[0055] (3) Calculate the positive and negative half-cycle integrals: For the transient current sequence i at the j-th monitoring terminal j (k), where j=1 or 2, calculate the positive half-cycle integral S within the analysis window respectively. j + and the absolute integral S of the negative half-cycle j - : (2) (3) In the formula, Δt is the sampling time interval, and the summation range is all sampling points within the analysis window. The positive and negative half-cycle integrals reflect the cumulative area of ​​the transient waveform on both sides of the zero axis.

[0056] (4) Calculate the normalized integral characteristic: The normalized integral characteristic Y of the j-th monitoring terminal is calculated based on the positive and negative half-cycle integrals. j : (4) In the formula, δ is a positive number set to prevent the denominator from being zero. Normalized integral eigenvalue Y j The value of Y ranges from 0 to 1. j The larger the value, the more prominent the dominant polarity of the transient current; Y j The smaller the value, the closer the positive and negative half-cycles of the waveform are.

[0057] Since this characteristic quantity is normalized by the sum of the positive and negative half-cycle integrals, when the overall amplitude of the waveform changes, the characteristic quantity mainly reflects the unipolarity or oscillatory symmetry of the waveform, rather than directly reflecting the absolute amplitude of the lightning current.

[0058] (5) Fusion of dual-end features: The arithmetic mean of the first-end feature quantity Y1 and the second-end feature quantity Y2 is used to obtain the combined feature quantity Y of both ends: (5) Using a dual-ended comprehensive feature quantity can reduce the discrimination fluctuations caused by local reflections, sensor noise, or channel gain deviations at a single monitoring end. In an optional implementation, when Y1 and Y2 are located on opposite sides of the criterion threshold, the dual-ended comprehensive feature quantity Y is still used as the final discrimination criterion.

[0059] (6) Compare the threshold criteria and output the type: Set a threshold ε for lightning strike type identification. Compare the combined feature quantity Y with the identification threshold ε: When Y ≥ ε, it is determined to be a direct lightning strike to the ground wire; when Y < ε, it is determined to be a lightning strike around a phase conductor.

[0060] The identification threshold ε is determined offline based on the structural parameters of the ice-melting line to be monitored, the bandwidth of the acquisition device, and representative waveforms. During calibration, sample characteristic quantities of the direct grounding wire and the winding phase conductor are obtained separately, and a threshold is selected between the distributions of the two types of characteristic quantities. In one embodiment, the identification threshold ε is set to 0.10; this value is not used as a fixed limitation for other lines.

[0061] refer to Figure 5 The flowchart for identifying lightning strike types using dual-ended integral features shows the sequence of dual-ended waveform acquisition, preprocessing, positive and negative half-cycle integration, feature calculation, dual-ended averaging, threshold comparison, and type output.

[0062] The discrimination principle of this application is as follows: When lightning strikes the ground wire directly, the lightning current is injected directly into the de-icing ground wire. After the transient current propagates along the ground wire to the monitoring points at both ends, the waveform usually consists of a main wave and an attenuated component of the same polarity during the main analysis period. Therefore, the integrals of the positive and negative half-cycles are significantly different, and the normalized integral characteristic is large.

[0063] When lightning strikes a phase conductor, the transient current in the ground wire is mainly generated by electromagnetic coupling between the conductor and the ground wire. The propagation and reflection of the traveling wave in the phase conductor couples into transient components with alternating directions in the ground wire, causing the ground wire monitoring waveform to oscillate around the zero axis. The integrals of the positive and negative half-cycles are relatively close, resulting in a small normalized integral characteristic.

[0064] By averaging the characteristic quantities at both ends, the effects of single-end boundary reflection and local waveform distortion can be reduced while preserving the aforementioned differences in waveform mechanism.

[0065] Specific embodiments of this application include: Taking an overhead transmission line that has undergone DC de-icing modification as an example, two ends of the de-icing ground wire section are selected as monitoring points. Each monitoring point is equipped with a transient current sensor and a data acquisition unit, with a sampling rate set to 10 MHz, recording the waveform before triggering and the waveform 1 ms after triggering. The two monitoring ends use unified time synchronization, and the positive current direction is defined as the direction from the inside of the de-icing section to the outside of the section.

[0066] After a candidate lightning strike event occurs, the background processing unit pairs the waveforms at both ends. It takes the data within 1 ms after the first wave arrives at both ends, subtracts the mean of the data before the trigger, and unifies the polarity. Then, it calculates the positive and negative half-cycle integrals of each monitoring end according to step (3), obtains Y1 and Y2 according to step (4), and then calculates the comprehensive characteristic quantity Y of both ends.

[0067] In this embodiment, the identification threshold ε=0.10 is determined in advance using typical simulated waveforms or calibration waveforms of the line to be monitored. When Y is not less than 0.10, "direct grounding" is output; when Y is less than 0.10, "strike around phase conductor" is output. The output information includes the event time, the original waveform numbers at both ends, Y1, Y2, the comprehensive characteristic quantity Y at both ends, and the lightning strike type.

[0068] For ice-melting sections of different lengths, sensor bandwidths, or wiring methods, the threshold can be recalibrated, but the processing flow of positive and negative half-cycle integration, normalized integral features, and dual-end comprehensive discrimination is still used.

[0069] Alternative implementation methods of this application: Integral characteristic calculation can be performed either in the backend server, at the monitoring end, or in an independent edge computing unit. Transient current waveforms can be input in real time or read from a historical waveform database.

[0070] When the sensor gains of different acquisition channels are inconsistent, each channel normalizes its positive and negative half-cycle integrals separately, eliminating the need to directly compare the absolute amplitudes of different channels. The independent identification results from multiple channels can be displayed or verified by the existing upper-level system.

[0071] The present invention has the following beneficial effects: (1) This invention converts the waveform difference between direct lightning strikes to the ground wire and lightning strikes to the phase conductor into the cumulative area difference of positive and negative half-cycles, and the criterion has a clear signal meaning.

[0072] (2) The present invention characterizes the waveform shape by normalizing the difference between positive and negative half-cycle integrals, thereby reducing the dependence on the absolute amplitude of lightning current and sensor gain.

[0073] (3) The present invention integrates the feature quantities of two monitoring ends, which can reduce the risk of misjudgment caused by local reflection, channel noise or waveform distortion of a single monitoring end.

[0074] (4) The present invention only needs to complete baseline correction, integration and threshold comparison, without relying on spectrum transformation and large-scale sample training, which makes it easy to implement in low-power online monitoring devices or edge computing units.

[0075] Key points and protections of this application: 1. Within a preset analysis window, with the zero axis as the boundary, accumulate the non-negative and negative sampled values ​​of the transient current waveform to obtain the positive half-cycle integral and the negative half-cycle absolute integral.

[0076] 2. Using the absolute value of the difference between the positive and negative half-cycle integrals as the numerator, and the sum of the two and a positive number that is close to zero as the denominator, a normalized integral difference characteristic quantity with a value range of 0 to 1 is constructed.

[0077] 3. A method for identifying direct lightning strikes to the ground wire and lightning strikes around the phase conductor by comparing the normalized integral difference feature with a preset threshold.

[0078] 4. A method for determining the analysis window and identification threshold by using representative waveforms for different lines or acquisition devices, while keeping the calculation methods for positive and negative half-cycle integrals and normalized differences unchanged.

[0079] 5. A lightning strike type identification device corresponding to the above method steps, comprising a waveform input unit, a preprocessing unit, a positive and negative half-cycle integration unit, a normalized feature calculation unit, and a threshold discrimination unit.

[0080] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method.

[0081] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0082] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0083] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0084] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0085] It is understood that the content of the above method embodiments is applicable to the embodiments of this program product. The specific functions implemented by the embodiments of this program product are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0086] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0087] This application provides a method, device, electronic device, storage medium, and program product for identifying lightning strike types on de-icing lines based on transient current integral characteristics. It acquires transient current waveforms of lightning strikes at both ends of the de-icing ground wire section. Utilizing the difference in mechanisms between direct lightning strikes to the ground wire forming a unipolar main wave and lightning strikes around a phase conductor generating an oscillating waveform through electromagnetic coupling, it calculates the normalized difference in the integral areas of the positive and negative half-cycles at the same monitoring end to quantify the unipolarity or oscillation symmetry of the waveform. Then, it averages the characteristic quantities at both ends to reduce single-end reflection and noise interference. Finally, it compares the combined characteristic quantities at both ends with a preset threshold, achieving accurate identification of direct lightning strikes to the ground wire and lightning strikes around a phase conductor type without relying on the absolute amplitude of the lightning current or a large-scale training sample.

[0088] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0089] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0090] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0091] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0092] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0093] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0094] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0095] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0096] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0097] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing programs, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0098] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for identifying lightning strike types on de-icing power lines based on transient current integral characteristics, characterized in that, The method includes the following steps: Obtain the transient current sequence to be judged; the transient current sequence is derived from the de-icing ground wire monitoring terminal; The transient current sequence is preprocessed to determine the analysis window used for integration calculation; Within the analysis window, the positive half-cycle integral is obtained based on the non-negative sampled values ​​of the transient current sequence, and the negative half-cycle absolute integral is obtained based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. The two-end comprehensive feature quantity is calculated based on the positive half-cycle integral and the negative half-cycle absolute integral. The dual-end integrated feature quantity is compared with a preset identification threshold, and the lightning strike type identification result is obtained based on the comparison result.

2. The method according to claim 1, characterized in that, The acquisition of the transient current sequence to be judged includes: A first monitoring terminal is set at one end of the ice-melting ground wire or fiber optic composite overhead ground wire of the DC ice-melting transformation line, and a second monitoring terminal is set at the other end. Each monitoring terminal is equipped with a transient current sensor and a data acquisition unit to record the waveform before triggering and the waveform for a preset time period after triggering. The first monitoring terminal and the second monitoring terminal are synchronized in a unified manner, and the positive current direction is taken as the direction from the inside of the ice-melting section to the outside of the section. After a candidate lightning strike event occurs, the waveforms of the first monitoring terminal and the second monitoring terminal are paired, and the data within a preset time after the arrival of the first wave at the first monitoring terminal and the second monitoring terminal are taken as the transient current sequence to be judged.

3. The method according to claim 1, characterized in that, The preprocessing of the transient current sequence to determine the analysis window for integration calculation includes: The transient current sequence is baseline corrected, the mean of the data before triggering is subtracted, and then preprocessed with power frequency component filtering, low frequency drift removal and high frequency noise suppression to obtain the waveform to be analyzed. The short-time energy exceeding a preset trigger threshold is used as the candidate event triggering condition; the short-time energy is calculated by summing the squares of the amplitudes of each sampling point within a preset short-time analysis window. When the short-term energy is greater than or equal to the trigger threshold, it is determined to be triggered; when the short-term energy is less than the trigger threshold, it is determined that no event has occurred and monitoring continues. Waveform pairing is performed based on the event time of the two monitoring terminals. When both monitoring terminals are triggered within the preset pairing time window, and the waveform to be analyzed has the characteristics of a lightning strike transient steep wavefront, pairing is confirmed. A segment of continuous sampling points of a preset length after the arrival of the first wave of transient current is extracted from the waveform to be analyzed after the pairing is confirmed, and used as an analysis window for integration calculation; the arrival time of the first wave of transient current is determined according to the time when the amplitude of the waveform to be analyzed first exceeds a set threshold.

4. The method according to claim 1, characterized in that, Within the analysis window, the positive half-cycle integral is obtained based on the non-negative sampled values ​​of the transient current sequence, and the negative half-cycle absolute integral is obtained based on the absolute values ​​of the negative sampled values ​​of the transient current sequence, including: For each monitoring terminal, within the analysis window, the amplitude of the non-negative sampled value in the transient current sequence of the same monitoring terminal is multiplied and accumulated by the sampling time interval, and the accumulated result is used as the positive half-cycle integral of the monitoring terminal. The absolute value of the amplitude of the negative sampled value in the transient current sequence of the same monitoring terminal is multiplied by the sampling time interval and accumulated. The accumulated result is used as the negative half-cycle absolute integral of the monitoring terminal.

5. The method according to claim 1, characterized in that, The calculation of the two-end comprehensive characteristic quantity based on the positive half-cycle integral and the negative half-cycle absolute integral includes: For each monitoring terminal, the normalized integral characteristic of each monitoring terminal is calculated by taking the absolute value of the difference between the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring terminal as the numerator, and the sum of the positive half-cycle integral and the negative half-cycle absolute integral of the same monitoring terminal and a positive number as the denominator. The normalized integral feature values ​​of each monitoring terminal are arithmetically averaged to obtain the combined feature value of both terminals.

6. The method according to claim 1, characterized in that, The step of comparing the dual-end integrated feature quantity with a preset identification threshold and obtaining the lightning strike type identification result based on the comparison result includes: When the combined feature quantity of the two ends is greater than or equal to the preset identification threshold, the lightning strike type is determined to be direct lightning strike to the ground wire; When the combined feature quantity of the two ends is less than the preset identification threshold, the lightning strike type is determined to be lightning strike on the phase conductor; Output the lightning strike type identification result; the lightning strike type identification result includes the event time, the waveform number of each monitoring end, the normalized integral feature of each monitoring end, the dual-end comprehensive feature, and the lightning strike type.

7. A device for identifying lightning strike types on de-icing lines based on transient current integral characteristics, characterized in that, The device includes: A waveform input unit is used to acquire the transient current sequence to be judged; the transient current sequence originates from the de-icing ground wire monitoring terminal. A preprocessing unit is used to preprocess the transient current sequence and determine the analysis window for integration calculation; An integration calculation unit is used to obtain the positive half-cycle integral based on the non-negative sampled values ​​of the transient current sequence within the analysis window, and to obtain the negative half-cycle absolute integral based on the absolute values ​​of the negative sampled values ​​of the transient current sequence. The feature quantity calculation unit is used to calculate the two-end comprehensive feature quantity based on the positive half-cycle integral and the negative half-cycle absolute integral. The threshold discrimination unit is used to compare the dual-end integrated feature quantity with the preset identification threshold, and obtain the lightning strike type identification result based on the comparison result.

8. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method according to any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 6.

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