Multiple lightning stroke current analysis method and surge protection device state evaluation and alarm method
By using multiple lightning current analysis methods and SPD health status correlation models, the problems of accurate identification of lightning events and untimely SPD status assessment in complex lightning environments are solved, realizing intelligent management and efficient alarm of lightning protection systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-07
AI Technical Summary
Existing technologies are insufficient to accurately identify multiple lightning strikes in complex lightning environments, cannot fully reflect the energy and destructive characteristics of lightning strikes, and have untimely SPD status assessment and alarms, as well as insufficient anti-interference capabilities.
A multi-step lightning strike current analysis method is adopted. By acquiring current signals in real time, lightning strike events are identified and current pulses are separated to obtain characteristic parameters. Combined with dynamic trigger baseline values and event window logic, an SPD health status correlation model is constructed to achieve accurate lightning strike waveform classification and equipment status assessment.
It improves the accuracy and robustness of lightning strike event identification, provides a high-quality data foundation, enables accurate assessment and timely alarm of SPD status, and enhances the intelligent management level of lightning protection systems.
Smart Images
Figure CN121805652A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of surge protection and lightning monitoring technology, and in particular to a method for analyzing multiple lightning currents and a method for assessing and alarming the status of surge protectors. Background Technology
[0002] Lightning is a violent, transient discharge phenomenon occurring in the atmosphere. Its physical essence lies in the extremely high potential difference formed by the accumulation of charge separation within, between, or between thunderstorm clouds and the ground, ultimately leading to the breakdown of the air medium and generating a giant pulse current lasting tens to hundreds of microseconds with a current amplitude reaching tens to hundreds of kiloamperes. Given the immense destructive power of lightning, scientific monitoring and in-depth analysis are necessary prerequisites for effective protection, disaster assessment, and risk management. A surge protection device (SPD) is an electronic device that provides safety protection for various electronic devices, instruments, and communication lines. The core mission of an SPD is to resist transient overvoltages and overcurrents caused by lightning electromagnetic pulses (LEMPs). SPDs are consumable protective devices; their core components (such as metal oxide varistors) undergo irreversible degradation under repeated surge impacts. Real-time and accurate monitoring of their status is crucial to ensuring the continuous safe operation of the protected system.
[0003] In existing technologies, current transformers or shunts are often used to sample lightning currents and identify lightning events through fixed thresholds or simple amplitude criteria. This is mainly used to count the number of lightning strikes or record the maximum discharge current.
[0004] However, in actual lightning environments, lightning strikes often manifest as complex waveforms of multiple return strokes or superimposed continuous pulses, especially under conditions of close-range lightning strikes or severe thunderstorms. A single lightning strike event may contain multiple current pulses with unequal time intervals and significantly different amplitudes. Existing technologies generally suffer from the following shortcomings: 1) It is difficult to effectively distinguish between a single lightning strike and multiple lightning strikes in a continuous current signal; 2) The analysis of lightning waveforms is mostly limited to the peak value or number of times, and the extraction of characteristic parameters is singular, which cannot fully reflect the energy and destructive characteristics of lightning strikes; 3) In complex electromagnetic environments, fixed thresholds and simple criteria are easily affected by noise and power frequency interference, resulting in insufficient anti-interference capabilities.
[0005] Meanwhile, those skilled in the art have recognized the correlation between SPD lifetime and lightning activity, but existing attempts are limited to simple spatiotemporal correlation (e.g., querying regional lightning data after an SPD failure). The lack of precise analysis of the raw lightning current pulses acting on the SPD, and the inability to dynamically correlate the analysis results with real-time SPD parameters, results in poor lightning protection capabilities. This leads to inaccurate analysis of lightning current, untimely assessment and alarm of SPD equipment status, and the fact that lightning current pulse analysis and SPD status assessment and alarm are two isolated technical processes. Summary of the Invention
[0006] In order to overcome the shortcomings of the prior art in terms of inaccurate analysis of lightning current and untimely assessment and alarm of SPD status, the present invention proposes a multiple lightning current analysis method and a surge protector status assessment and alarm method.
[0007] To achieve the above objectives, the present invention adopts the following technical solution, including: A method for analyzing multiple lightning strike currents includes: S1: Real-time acquisition of current signals in the target area, the current signal being the current signal in the discharge circuit of the surge protector; S2: Identify lightning strike events by analyzing the current signal in the target area and separate several current pulses in the lightning strike event. For each separated current pulse, the characteristic parameters of the current pulse are obtained. The characteristic parameters of the current pulse include pulse peak value, wavefront time, wavetail time, specific energy, and charge.
[0008] Preferably, step S2 includes: S21: When the current signal exceeds the main trigger threshold, a valid lightning strike event is marked as starting. At the same time, an event window with a configurable duration is immediately started. Within the event window, if the current signal at all sampling time points is lower than the secondary trigger threshold and the absolute value of the slope of the current signal at all sampling time points is less than the first threshold K, then the valid lightning strike event is determined to have ended. The main trigger threshold is set proportionally according to the nominal discharge current of the surge protector. S22: For each lightning strike event, identify all current pulses, including the start and end points of the current pulses; within the same event window T_event, all identified current pulses belong to the same lightning strike event; S23: For each separated current pulse, obtain the characteristic parameters of the current pulse. The characteristic parameters of the current pulse include pulse peak value, wavefront time T1, wavetail time T2, specific energy and charge. S24: For each current pulse, perform waveform classification based on the pulse waveform feature classification library, and update the pulse waveform feature classification library using new current pulse data; the predefined types of pulse waveform categories include first return stroke waveform, subsequent return stroke waveform, and long-duration lightning strike waveform.
[0009] Preferably, in step S21, the calculation of the trigger threshold includes: S211: In the absence of triggering the main trigger threshold, select a length of... The sliding time window, for the sliding time window The current signal at each sampling time point within the range is used to calculate and obtain the real-time baseline value. :
[0010] in: The current signal varies with time; i is the current; t is the sampling time point; , N is the sampling frequency; N is the number of sampling time points within the sliding time window; T base The duration of the sliding time window; S212: Obtain the dynamically triggered baseline value based on the real-time baseline value. The calculation formula is as follows:
[0011] in, The dynamic trigger baseline value for the current time point t; The baseline value was dynamically triggered at the previous moment; For smoothing coefficients; S213: Obtaining the trigger threshold based on the dynamic trigger baseline value The calculation method is as follows:
[0012] Where k is the compensation coefficient; when t is 0, the initial value I of the trigger threshold is... sub (0) Set the main trigger threshold to 10% to 30%; Preferably, in step S22, the start and end points of the current pulse are determined: Starting point: The current signal rises from the pulse separation baseline. If the current signal exceeds the trigger threshold in N consecutive sampling time points, and the slope of the current signal is greater than S_min in N consecutive sampling time points, it is determined to be the pulse starting point. End point: After the pulse peak, the current signal falls back to within ±5% of the pulse separation baseline, and the absolute value of the slope of the current signal at M consecutive sampling time points is less than S_min, which is determined to be the end point of the pulse; S_min is the set slope threshold.
[0013] Preferably, in step S23, the calculation of the characteristic parameters of the current pulse includes: S231: Obtain the peak value of the current pulse, that is, the maximum value of the current in a current pulse; S232: Starting from the beginning of the current pulse, find the point t1 where the current signal reaches 10% of the pulse peak value and the point t2 where it reaches 90% of the pulse peak value. Then the wavefront time T1 = t2 - t1; find the point t3 where the pulse peak value drops to 50%. Then the wave tail time T2 = t3 - t1. S233: Numerical integration is performed on the separated single pulse waveform data using the numerical integration method; Specific energy BN: For the baseline-corrected current signal, the squared current value at each sampling time point is integrated over time using the trapezoidal integral method, BN = i²dt; Charge DH: For the baseline-corrected current signal, time integration is performed using the trapezoidal integral method, DH = idt.
[0014] A surge protector status assessment and alarm method employs a multiple lightning strike current analysis method to identify lightning strike events, obtain all current pulses present in each lightning strike event, acquire the characteristic parameters of each current pulse, and then assess and alarm the surge protector status, including: Sa1: Calculate the event complexity index CI based on the characteristic parameters of all current pulses in a single lightning strike event; the calculation formula is:
[0015] Where MC is the number of pulses; SDH is the total charge, which is the sum of charges DH; SBN is the total specific energy, which is the sum of specific energies BN; S is the steepness factor; Q_n is the nominal charge capacity of the surge protector (SPD); E_n is the nominal specific energy of the SPD; T1_ref is the reference standard wavefront time; and T1_avg is the average value of the current pulse wavefront time within this lightning strike event. Sa2: Construct a health status correlation model for the surge protector to obtain the final health score, including: The initial health score H of the SPD is obtained using the following formula: H=100–[C_ratio×0.6+E_ratio×0.25+S_ratio×0.15+D×0.1]×100 Where C_ratio is the proportion of total charge; E_ratio is the proportion of maximum single specific energy; S_ratio is the lightning strike steepness proportion factor; and D is the degradation coefficient. Based on the lightning strike event complexity index and the initial health score of the surge protector (SPD), the final health score H′ of the surge protector is calculated using the following formula:
[0016] Where K_CI is the health correction coefficient; γ is the complexity influence coefficient; Sa3: The surge protector is evaluated and alarmed based on its final health score and the total charge of the lightning strike.
[0017] Preferably, step Sa3 includes: When the total charge is ≤ 60% of the SPD's nominal charge capacity or the final health score When the score is ≥90, it is in the safe operating zone and there are no alarms. When the total charge is ≥ 60% of the SPD's nominal charge capacity or the final health score is ≤ 80 A score of <90 will trigger a Level 1 risk warning, i.e., a warning to be aware of the risks. When the total charge is ≥ 70% of the SPD's nominal charge capacity or the final health score is ≤ 60 A score below 80 will trigger a Level 2 risk warning. When the total charge is ≥ 80% of the SPD's nominal charge capacity or the final health score If the score is less than 60 points or the maximum single specific energy is greater than or equal to 90% of the SPD's nominal specific energy, a Level 3 risk warning will be issued, i.e., a severe warning. An emergency alarm will be triggered directly when the total charge is ≥ 70% of the SPD's nominal charge capacity and any of the following conditions are met simultaneously. Health score <70 points; The peak value of a single pulse reaches the nominal discharge current.
[0018] Preferably, the total charge percentage C_ratio is calculated as follows: C_ratio=SDH / Q_n Where SDH is the total charge; Q_n is the nominal charge capacity of the SPD; The maximum single-phase specific energy ratio E_ratio is calculated as follows: E_ratio=E_max / E_n Where E_max is the maximum specific energy in a single operation; E_n is the nominal specific energy of the SPD; E_n = Uc × Q_n, where Uc is the continuous operating voltage of the SPD; The calculation method for the lightning strike steepness ratio factor S_ratio is as follows: S_ratio=T1_ref / T1_min T1_ref is the reference standard wavefront time; T1_min is the minimum wavefront time within the statistical period; The degradation factor D is calculated as follows: D=α×(t / t_n)+β×(Uc_initial-Uc_current / Uc_initial) Where: t is the runtime; t_n is the SPD design lifetime; Uc_initial is the initial residual voltage; Uc_current is the current residual voltage; α and β are weighting coefficients determined based on experiments on the SPD degradation mechanism.
[0019] A readable storage medium having a computer program stored thereon, which, when executed, implements a surge protector status assessment and alarm method.
[0020] An electronic device includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a surge protector status assessment and alarm method.
[0021] The advantages of this invention are: (1) This invention, through innovative dynamic trigger baseline values combined with master / slave trigger thresholds and event window judgment logic, effectively resists the effects of power frequency interference, environmental noise, and DC offset, significantly reducing the false trigger rate and ensuring the reliability of lightning event identification in complex electromagnetic environments. By employing a starting slope criterion + an ending dynamic fallback criterion, combined with event window attribution logic, the technical challenge of accurately separating multiple independent current pulses with unequal intervals and amplitudes in a single lightning strike event is successfully solved. This enables the invention not only to identify single impacts but also to accurately analyze real lightning scenarios such as multiple return strokes and continuous pulse superposition, providing a structured, high-quality data foundation for subsequent feature extraction and risk assessment. It improves the accuracy and robustness of lightning event identification, achieving accurate analysis of complex multiple lightning strikes.
[0022] (2) Unlike existing technologies that only focus on peak value or number of pulses, this invention systematically extracts multi-dimensional characteristic parameters for each separated current pulse, including pulse peak value, wavefront time, wavetail time, specific energy, and charge. The parameter calculation uses the benchmark method (e.g., 10%-90%) recommended by the International Standard for Electron Diagnostics (IEC) and the numerical integration method, ensuring the objectivity and comparability of the feature extraction. This provides accurate and complete quantitative basis for subsequent waveform classification, energy assessment, and comparison analysis with SPD characteristic parameters.
[0023] (3) Based on a pre-built pulse waveform feature classification library, the system can automatically classify current pulses into standard or custom categories such as first return stroke, subsequent return stroke, and long-term lightning strike, thus achieving preliminary intelligent identification of lightning waveforms. The introduction of an incremental learning update mechanism enables the pulse waveform feature classification library to be continuously optimized and iterated with the accumulation of new measured data. The system has self-learning and adaptability, and can better reflect the characteristics of lightning activity in local or specific scenarios, thereby improving the generalization ability and long-term applicability of the model.
[0024] (4) This invention weights and fuses multiple key features of a single lightning strike event, such as the number of pulses, total charge, total specific energy, and pulse steepness (mean wavefront time), to generate a comprehensive complexity index (CI). The CI value objectively and quantitatively reflects the complexity of a single lightning strike event and its cumulative and synergistic impact on the SPD, changing the previous one-sided evaluation method that only focused on the maximum value of a single pulse, and providing a crucial basis for event-level impact intensity correction for the health assessment of the SPD.
[0025] (5) The SPD health status correlation model constructed in this invention not only considers traditional key electrical parameters (such as total charge and maximum specific energy), but also innovatively introduces the lightning steepness ratio factor and the degradation coefficient reflecting the aging and performance degradation of the SPD itself. This model dynamically correlates external impacts (lightning characteristics) with internal conditions (equipment degradation), and corrects the basic health status through the CI index, ultimately obtaining the final health score (H′) of the surge protector. This makes the evaluation results no longer an isolated "lightning statistics" or "equipment self-test", but a true reflection of the remaining protection capability and life status of the SPD under a specific lightning stress history, achieving precision and foresight in condition assessment.
[0026] (6) The alarm strategy of this invention abandons the single threshold judgment and instead makes a dual judgment based on the total charge accumulation level and the dynamically updated final health score, forming a multi-level alarm system including safety, attention, warning, serious warning, and emergency alarm. This alarm mechanism can not only warn of the risk of chronic degradation caused by the accumulated energy approaching the upper limit, but also promptly capture the risk of "acute damage" caused by a single extremely high energy or abnormal steep impact, and can identify high-risk lightning strike patterns in advance through the complexity index. This provides maintenance personnel with complete decision support from observation and prediction to emergency response, significantly improving the initiative and reliability of the lightning protection system.
[0027] (7) The most significant advancement of this invention lies in the deep integration of high-precision analysis technology of lightning current waveforms and SPD device status assessment technology from two isolated links into an organic whole. By sharing the same data source (SPD loop current) and a unified characteristic parameter system, seamless connection between data flow and business flow is achieved. This integrated closed-loop system can transform the fingerprint characteristics of each lightning strike into a specific impact assessment on the health of the SPD in real time, and immediately output diagnostic reports and alarm information. This not only greatly improves monitoring efficiency, but also lays a solid technical foundation for realizing intelligent management and status-based predictive maintenance of regional lightning protection networks. At the same time, it significantly improves the intelligence level of lightning monitoring and the accuracy and timeliness of SPD health status assessment. It has significant practical value and broad application prospects for ensuring the lightning protection safety of key infrastructures such as power, communication, and transportation, and reducing the risk of secondary disasters caused by SPD failure. Attached Figure Description
[0028] Figure 1 A flowchart illustrating the steps involved in surge protector status assessment and alarm procedures. Figure 2 Diagram of an effective lightning strike and current pulse identification architecture; Figure 3 This diagram illustrates the architecture for intelligent early warning and diagnostic report output from surge protectors. Detailed Implementation
[0029] 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, and 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.
[0030] Example 1
[0031] like Figure 1-3 As shown, this invention proposes a method for analyzing multiple lightning strike currents, including: S1: Real-time acquisition of current signals in the target area, wherein the current signal is the current signal in the discharge circuit of the surge protection device (SPD). The surge protection device (SPD) is placed in the target area, with a current sensing unit (Rogowski coil) installed in the SPD's grounding lead. This location accurately reflects the transient current characteristics flowing through the SPD during lightning strikes or overvoltage events, making it suitable as a data source for lightning waveform monitoring and analysis. The current signal flowing through the surge protection device is acquired at a sampling rate of 2 MS / s, and the current signal data stream is cyclically stored in a high-speed cache.
[0032] S2: Identify lightning strike events by analyzing the current signal in the target area and separate several current pulses within the lightning strike event.
[0033] The system analyzes the current signal data stream based on preset dynamic triggering criteria and event window logic to identify the start, progress, and end of a lightning strike event, and accurately separates multiple current pulses in a complex event. This step specifically includes: S21: When the current signal exceeds the main trigger threshold, a valid lightning strike event is marked as starting. At the same time, an event window with a configurable duration (e.g., from 50ms to 1000ms) is immediately started. Within the event window, if the current signal at all sampling time points is lower than the main trigger threshold and the absolute value of the slope of the current signal at all sampling time points is less than the first threshold K (e.g., 0.1A / ms) within a set time T_quiet (e.g., 10ms), the valid lightning strike event is determined to have ended.
[0034] The main trigger threshold is set proportionally to the nominal discharge current of the SPD, for example, 20% of the nominal discharge current of the SPD.
[0035] The trigger threshold is determined based on the dynamic trigger baseline value, specifically as follows: S211: In the absence of triggering the main trigger threshold, select a length of... A sliding time window (e.g., 50ms to 200ms) is used to calculate the current signal at the sampling time points within this sliding time window, and obtain the real-time baseline value. :
[0036] in: The current signal varies with time; i is the current; t is the sampling time point; , N is the sampling frequency; N is the number of sampling time points within the sliding time window; T base The duration of the sliding time window; the real-time baseline value can be calculated using the sliding time window averaging method or the median method.
[0037] S212: The dynamic trigger baseline value is obtained based on the real-time baseline value using a first-order recursive filtering (exponential weighted average) method. The calculation formula is as follows:
[0038] in, The dynamic trigger baseline value at the current time t; The baseline value was dynamically triggered at the previous moment; This is a smoothing coefficient, with a value ranging from 0.9 to 0.99.
[0039] S213: Obtaining dynamic trigger thresholds based on dynamic trigger baseline values The calculation method is as follows:
[0040] Where k is the compensation coefficient, with a value ranging from 0.8 to 1.2; when t==0, the initial value of the trigger threshold I is used. sub (0) Set to 10% to 30% of the main trigger threshold.
[0041] To account for the impact of background current offset on small-amplitude return stroke recognition, a linear compensation method based on dynamic baseline values is adopted in the design of the trigger threshold.
[0042] S22: For each lightning strike event, identify all current pulses, including the start and end points of the current pulses.
[0043] Baseline correction: Before the lightning strike event begins, a moving average method (window length selectable 100 ms) is used to calculate the pulse separation baseline in real time, and it is updated every 1 ms to eliminate the effects of DC offset and low-frequency interference. The pulse separation baseline is the horizontal line formed by the average current signal over a set time period.
[0044] Determining the start and end points of a current pulse: Starting point: The current signal rises from the pulse separation baseline. If the current signal exceeds the trigger threshold in N consecutive sampling time points (e.g., N=5), and the slope of the current signal is greater than S_min (e.g., 1A / μs) in N consecutive sampling time points, it is determined to be the pulse starting point.
[0045] End point: After the pulse peak, the current signal falls back to near the pulse separation baseline (e.g., within ±5% of the baseline range), and the absolute value of the current signal slope at M consecutive sampling points (M=10) is less than S_min. This is determined as the end point of the pulse. S_min is the set slope threshold.
[0046] Pulse attribution logic: Within the same event window T_event, all identified current pulses belong to the same lightning strike event.
[0047] S23: For each separated current pulse, obtain the characteristic parameters of the current pulse. The characteristic parameters of the current pulse include the pulse peak value, wavefront time T1, wavetail time T2, specific energy, and charge.
[0048] T1 / T2 is calculated by linear interpolation using a reference point method of 10%-90% or 30%-90%; specific energy and charge are calculated by numerical integration methods (such as trapezoidal integrals).
[0049] S231: Obtain the peak value of the current pulse, that is, the maximum value of the current in a current pulse; S232: Calculation of wavefront time (T1) and wavetail time (T2) Benchmark point determination: Use the 10%-90% method or the 30%-90% method (for lightning current) according to industry standards (such as IEC standards).
[0050] Algorithm implementation: Starting from the beginning of the current pulse, use linear interpolation to find the point (t1) where the current signal reaches 10% (or 30%) of the pulse peak value and the point (t2) where it reaches 90% of the pulse peak value. Then the wavefront time T1 = t2 - t1. Similarly, find the point (t3) where the pulse peak value drops to 50%. Then the wave tail time T2 = t3 - t1.
[0051] S233: Calculation of Specific Energy and Charge
[0052] Numerical integration method: Numerical integration is performed on the isolated individual pulse waveform data.
[0053] Specific Energy (BN): For the baseline-corrected current signal, the squared current value at each sampling time point is integrated over time using the trapezoidal integral method. BN = i²dt.
[0054] Charge (DH): For the baseline-corrected current signal, time integration is performed using the trapezoidal integral method, DH = idt.
[0055] S24: Classify each current pulse based on the pulse waveform feature classification library, and update the pulse waveform feature classification library using new current pulse data.
[0056] A pulse waveform feature classification library is established based on international standards (such as IEC 62305 and IEC 61643) and historical lightning strike data (predefined feature parameters). At the same time, by using the extracted current pulse feature parameters (peak value, T1, T2, specific energy, etc.), each current pulse is automatically classified into a predefined type of pulse waveform category through nearest neighbor classification or decision tree model.
[0057] Predefined types of pulse waveforms include, but are not limited to: first return stroke waveform (typical parameter range: wavefront time 1-10μs, wavetail time 20-200μs), subsequent return stroke waveform (wavefront time is usually shorter and energy is lower), and long-duration lightning strike waveform (wavetail time can reach hundreds of ms to several seconds).
[0058] Pulse waveform feature classification library update mechanism: Supports incremental training based on new measured data, and automatically iterates and optimizes model parameters every 500 sets of new data.
[0059] Example 2
[0060] This invention proposes a surge protector status assessment and alarm method. First, a multiple lightning strike current analysis method is used to identify lightning strike events, obtaining all current pulses present in each lightning strike event and acquiring the characteristic parameters of each current pulse. Then, the surge protector status is assessed and alarmed, including: Sa1: In a lightning strike event, the complexity index CI is calculated based on the characteristic parameters of all current pulses. The calculation formula is as follows:
[0061] Wherein, MC is the number of pulses; SDH is the total charge, i.e., the sum of charges DH; SBN is the total specific energy, i.e., the sum of specific energies BN; S is the steepness factor; Q_n is the nominal charge capacity of the SPD; E_n is the nominal specific energy of the SPD; T1_ref is the reference standard wavefront time, usually taken as 8μs, or selected in the range of 5 to 10μs according to the pulse waveform characteristic classification library; T1_avg is the average value of the current pulse wavefront time within the lightning strike event; CI takes a value of 0-1.0, which is used to correct the surge protector health assessment results in subsequent steps and serves as an important basis for lightning strike risk classification.
[0062] Time-energy correlation analysis: For multiple pulses in the same lightning strike event, the sequence characteristics such as time interval distribution and energy decay trend are analyzed to identify typical multiple lightning strike modes (such as consecutive return strokes and long-interval subsequent flashes). The lightning event complexity index (CI) is used to assess the severity of lightning strike events and their potential impact on SPDs (Special Purpose Devices).
[0063] Sa2: Construct a health status correlation model for the surge protector to obtain the final health score, including: The initial health score H of the SPD is obtained using the following formula: H=100–[C_ratio×0.6+E_ratio×0.25+S_ratio×0.15+D×0.1]×100 Where C_ratio is the proportion of total charge; E_ratio is the proportion of maximum single specific energy; S_ratio is the lightning strike steepness proportion factor; and D is the degradation coefficient.
[0064] Table 1 Calculation of Input Parameters
[0065] The SPD health status association model is a multiple linear regression model.
[0066] Based on the lightning strike event complexity index and the initial health score of the surge protector (SPD), the final health score H′ of the surge protector is calculated using the following formula:
[0067] Wherein, K_CI is the health correction coefficient; γ is the complexity influence coefficient, which is configured according to the surge protector model, application scenario and lightning strike environment, and is usually taken as 0.1 to 0.3; H is the health score.
[0068] After completing the basic health assessment (the initial health score of the SPD), the lightning event complexity index CI is introduced to dynamically correct the health results, so as to reflect the additional impact of high-complexity lightning events on the surge protector in a short period of time.
[0069] Sa3: Based on the surge protector's final health score and the total charge of the lightning strike, the surge protector is evaluated and alarmed; When the total charge is ≤ 60% of the SPD's nominal charge capacity or the final health score When the score is ≥90, it is in the safe operating zone and there are no alarms. When the total charge is ≥ 60% of the SPD's nominal charge capacity or the final health score is ≤ 80 A score of <90 will trigger a Level 1 risk warning, i.e., a warning to be aware of the risks. When the total charge is ≥ 70% of the SPD's nominal charge capacity or the final health score is ≤ 60 A score below 80 will trigger a Level 2 risk warning. When the total charge is ≥ 80% of the SPD's nominal charge capacity or the final health score If the score is less than 60 points or the maximum single specific energy is greater than or equal to 90% of the SPD's nominal specific energy, a Level 3 risk warning will be issued, i.e., a severe warning. An emergency alarm will be triggered directly when the total charge is ≥ 70% of the SPD's nominal charge capacity and any of the following conditions are met simultaneously.
[0070] Health score <70 points; The peak value of a single pulse reaches (approaches or exceeds) the nominal discharge current.
[0071] Diagnostic report output: Generates a structured report containing fields such as the number of lightning strikes, lightning energy, maximum peak value, number of pulses, and final SPD health score (H′), and supports remote transmission to the monitoring platform.
[0072] When a lightning strike with a high CI occurs within the statistical period, it is believed that although such an event may not have reached the degradation threshold in terms of cumulative energy, its multi-pulse, high-steepness, or concentrated energy release characteristics will accelerate the transient aging process of the internal components of the surge protector.
[0073] By correlating lightning waveform characteristic parameters, lightning event complexity, and surge protector operating parameters, a method for assessing the health status and providing early warning of degradation of surge protectors based on lightning impact characteristics is established.
[0074] A readable storage medium having a computer program stored thereon, which, when executed, implements a surge protector status assessment and alarm method.
[0075] An electronic device includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a surge protector status assessment and alarm method.
[0076] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0077] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0078] The technologies, shapes, and structures not described in detail in this invention are all known technologies.
Claims
1. A method for analyzing multiple lightning strike currents, characterized in that, include: S1: Real-time acquisition of current signals in the target area, the current signal being the current signal in the discharge circuit of the surge protector; S2: Identify lightning strike events by analyzing the current signal in the target area and separate several current pulses in the lightning strike event. For each separated current pulse, the characteristic parameters of the current pulse are obtained. The characteristic parameters of the current pulse include pulse peak value, wavefront time, wavetail time, specific energy, and charge.
2. The method for analyzing multiple lightning strike currents as described in claim 1, characterized in that, Step S2 includes: S21: When the current signal exceeds the main trigger threshold, a valid lightning strike event is marked as starting. At the same time, an event window with a configurable duration is immediately started. Within the event window, if the current signal at all sampling time points is lower than the secondary trigger threshold and the absolute value of the slope of the current signal at all sampling time points is less than the first threshold K, then the valid lightning strike event is determined to have ended. The main trigger threshold is set proportionally according to the nominal discharge current of the surge protector. S22: For each lightning strike event, identify all current pulses, including the start and end points of the current pulses; within the same event window T_event, all identified current pulses belong to the same lightning strike event; S23: For each separated current pulse, obtain the characteristic parameters of the current pulse. The characteristic parameters of the current pulse include pulse peak value, wavefront time T1, wavetail time T2, specific energy and charge. S24: For each current pulse, perform waveform classification based on the pulse waveform feature classification library, and update the pulse waveform feature classification library using new current pulse data; the predefined types of pulse waveform categories include first return stroke waveform, subsequent return stroke waveform, and long-duration lightning strike waveform.
3. The method for analyzing multiple lightning strike currents as described in claim 2, characterized in that, In step S21, the calculation of the trigger threshold includes: S211: In the absence of triggering the main trigger threshold, select a length of... The sliding time window, for the sliding time window The current signal at each sampling time point within the range is used to calculate and obtain the real-time baseline value. : in: The current signal varies with time; i is the current; t is the sampling time point; , N is the sampling frequency; N is the number of sampling time points within the sliding time window; T base The duration of the sliding time window; S212: Obtain the dynamically triggered baseline value based on the real-time baseline value. The calculation formula is as follows: in, The dynamic trigger baseline value for the current time point t; The baseline value was dynamically triggered at the previous moment; For smoothing coefficients; S213: Obtaining the trigger threshold based on the dynamic trigger baseline value The calculation method is as follows: Where k is the compensation coefficient; when t is 0, the initial value I of the trigger threshold is... sub (0) Set to 10% to 30% of the main trigger threshold.
4. The method for analyzing multiple lightning strike currents as described in claim 2, characterized in that, In step S22, the start and end points of the current pulse are determined: Starting point: The current signal rises from the pulse separation baseline. If the current signal exceeds the trigger threshold in N consecutive sampling time points, and the slope of the current signal is greater than S_min in N consecutive sampling time points, it is determined to be the pulse starting point. End point: After the pulse peak, the current signal falls back to within ±5% of the pulse separation baseline, and the absolute value of the slope of the current signal at M consecutive sampling time points is less than S_min, which is determined to be the end point of the pulse; S_min is the set slope threshold.
5. The method for analyzing multiple lightning strike currents as described in claim 2, characterized in that, In step S23, the calculation of the characteristic parameters of the current pulse includes: S231: Obtain the peak value of the current pulse, that is, the maximum value of the current in a current pulse; S232: Starting from the beginning of the current pulse, find the point t1 where the current signal reaches 10% of the pulse peak value and the point t2 where it reaches 90% of the pulse peak value. Then the wavefront time T1 = t2 - t1; find the point t3 where the pulse peak value drops to 50%. Then the wave tail time T2 = t3 - t1. S233: Numerical integration is performed on the separated single pulse waveform data using the numerical integration method; Specific energy BN: For the baseline-corrected current signal, the squared current value at each sampling time point is integrated over time using the trapezoidal integral method, BN = i²dt; Charge DH: For the baseline-corrected current signal, time integration is performed using the trapezoidal integral method, DH = idt.
6. A method for assessing and alarming the status of a surge protector, characterized in that, A multiple lightning strike current analysis method as described in any one of claims 1 to 5 is used to identify lightning strike events, obtain all current pulses present in each lightning strike event, acquire the characteristic parameters of each current pulse, and then evaluate and alarm the surge protector status, including: Sa1: Calculate the event complexity index CI based on the characteristic parameters of all current pulses in a single lightning strike event; the calculation formula is: Where MC is the number of pulses; SDH is the total charge, which is the sum of charges DH; SBN is the total specific energy, which is the sum of specific energies BN; S is the steepness factor; Q_n is the nominal charge capacity of the surge protector (SPD); E_n is the nominal specific energy of the SPD; T1_ref is the reference standard wavefront time; and T1_avg is the average value of the current pulse wavefront time within this lightning strike event. Sa2: Construct a health status correlation model for the surge protector to obtain the final health score, including: The initial health score H of the SPD is obtained using the following formula: H=100–[C_ratio×0.6+E_ratio×0.25+S_ratio×0.15+D×0.1]×100 Where C_ratio is the proportion of total charge; E_ratio is the proportion of maximum single specific energy; S_ratio is the lightning strike steepness proportion factor; and D is the degradation coefficient. Based on the lightning strike event complexity index and the initial health score of the surge protector (SPD), the final health score H′ of the surge protector is calculated using the following formula: Where K_CI is the health correction coefficient; γ is the complexity influence coefficient; Sa3: The surge protector is evaluated and alarmed based on its final health score and the total charge of the lightning strike.
7. The surge protector status assessment and alarm method as described in claim 6, characterized in that, Step Sa3 includes: When the total charge is ≤ 60% of the SPD's nominal charge capacity or the final health score When the score is ≥90, it is in the safe operating zone and there are no alarms. When the total charge is ≥ 60% of the SPD's nominal charge capacity or the final health score is ≤ 80 A score of <90 will trigger a Level 1 risk warning, i.e., a warning to be aware of the risks. When the total charge is ≥ 70% of the SPD's nominal charge capacity or the final health score is ≤ 60 A score below 80 will trigger a Level 2 risk warning. When the total charge is ≥ 80% of the SPD's nominal charge capacity or the final health score If the score is less than 60 points or the maximum single specific energy is greater than or equal to 90% of the SPD's nominal specific energy, a Level 3 risk warning will be issued, i.e., a severe warning. An emergency alarm will be triggered directly when the total charge is ≥ 70% of the SPD's nominal charge capacity and any of the following conditions are met simultaneously. Health score <70 points; The peak value of a single pulse reaches the nominal discharge current.
8. The surge protector status assessment and alarm method as described in claim 6, characterized in that, The total charge percentage C_ratio is calculated as follows: C_ratio=SDH / Q_n Where SDH is the total charge; Q_n is the nominal charge capacity of the SPD; The maximum single-phase specific energy ratio E_ratio is calculated as follows: E_ratio=E_max / E_n Where E_max is the maximum specific energy in a single operation; E_n is the nominal specific energy of the SPD; E_n = Uc × Q_n, where Uc is the continuous operating voltage of the SPD; The calculation method for the lightning strike steepness ratio factor S_ratio is as follows: S_ratio=T1_ref / T1_min T1_ref is the reference standard wavefront time; T1_min is the minimum wavefront time within the statistical period; The degradation factor D is calculated as follows: D=α×(t / t_n)+β×(Uc_initial-Uc_current / Uc_initial) Where: t is the runtime; t_n is the SPD design lifetime; Uc_initial is the initial residual voltage; Uc_current is the current residual voltage; α and β are weighting coefficients determined based on experiments on the SPD degradation mechanism.
9. A readable storage medium, characterized in that, It stores a computer program, which, when executed, implements a surge protector status assessment and alarm method according to any one of claims 6 to 8.
10. An electronic device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the surge protector status assessment and alarm method according to any one of claims 6 to 8.
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