67 results about "Lightning overvoltage" patented technology

The invention discloses an electric energy metering box fault prediction method and system based on big data analysis, relates to the technical field of smart power grids, and solves the problems of progressive aging missing detection and instantaneous interference misjudgment caused by dependence on single parameter threshold alarm and fault positioning misalignment caused by multi-source data isolated analysis in the prior art. According to the scheme, electrical, environment and equipment state parameters are collected in real time through a multi-dimensional sensing network; the error drift of the mutual inductor is dynamically predicted based on an LSTM-Kalman filtering model, and core breakdown early warning is realized in combination with wavelet transform; outputting a corrected resistance value and a fault mark by using a BP neural network; predicting the life of the piezoresistor by adopting a gradient boosting decision tree and fusing lightning overvoltage characteristics; the transient interference is suppressed through the combination of a Transform self-attention mechanism and dynamic time warping; according to the method, the aging detection precision and the complex environment adaptability are remarkably improved, the misjudgment rate is reduced, and the multi-fault associated positioning and active defense capability is realized.

The invention discloses a + / -800kV converter station lightning arrester insulation cooperation checking method considering multiple lightning strokes, and the method comprises the steps: S1, building a high-frequency electromagnetic transient simulation model according to the engineering practice and the high-frequency demands of lightning overvoltage simulation calculation; s2, multiple lightning stroke lightning current waveform parameters and lightning stroke time intervals are selected, and parameters capable of representing different frequencies of ground-to-ground lightning in the region where the research object is located are obtained; s3, simulating and analyzing residual voltage, current and absorbed energy of the lightning arrester at different positions of multiple lightning / multiple lightning shielding failure; s4, comparing and analyzing amplitude values of residual voltage, current and absorbed energy of the lightning arrester under single lightning stroke / multiple lightning stroke, and selecting a maximum value; and S5, proposing a lightning arrester configuration scheme, adjusting the type of the lightning arrester in the simulation model, and repeating the steps S3 and S4 to carry out secondary checking and adjustment. According to the method, a lightning arrester type selection scheme capable of effectively inhibiting single lightning overvoltage and multiple lightning overvoltage is provided, and the lightning accident rate of the lightning arresters in the converter station is reduced.

The invention provides a series gap lightning arrester electromagnetic transient simulation analysis method and device and electronic equipment. The method comprises the following steps: according to a Heidler function, creating a lightning simulation model of the overvoltage of the lightning intrusion wave of the power transmission line; the method comprises the following steps: acquiring system parameters of a power transmission line, creating an electromagnetic transient simulation model of the power transmission line provided with a series gap lightning arrester according to the system parameters of the power transmission line, and calculating simulation data at each monitoring point of the power transmission line under the action of lightning overvoltage by adopting the electromagnetic transient simulation model and a lightning simulation model, and carrying out safety performance evaluation on the series gap lightning arrester according to the simulation data. By constructing the lightning simulation model and the electromagnetic transient simulation model, the series gap lightning arrester is simulated, the safety performance of the series gap lightning arrester in the power transmission line is evaluated, and the problems that in the prior art, the requirement for computing resources is large, and the computing period is long are solved.

The present invention belongs to the technical field of lightning protection of power transmission lines, and in particular, relates to a method for limiting lightning overvoltage of a direct-current power transmission line. By means of using operation date of a line itself, lightning current monitoring data, and parameters of an environment where the line is located, a line dynamic operation function curve and a line lightning-protection performance function curve are both corrected to obtain a more realistic voltage difference, thus achieving reliable protection actions and state sensing of a lightning arrester on the line. An apparatus for limiting a lightning overvoltage of a direct-current power transmission line is further provided in the present invention to cooperate with the implementation of the method.

The invention discloses a design method for a ZnO valve plate impact tolerance test current waveform considering typical external overvoltage, and the method comprises the steps: S1, drawing up a lightning overvoltage working condition according to a research demand, and analyzing system parameters and equipment parameters needed for building an electromagnetic transient simulation model; s2, building a high-frequency model required by lightning overvoltage simulation, wherein the high-frequency model comprises a high-frequency equivalent model of each key device and a lightning current source; s3, simulating the impulse current in the lightning arrester under the lightning overvoltage fault simulated by the actual lightning parameters; and S4, analyzing the wavefront time and the wave tail time of the impact current in the lightning arrester under each lightning overvoltage fault, and drawing up the wavefront time and the wave tail time of the impact current in combination with test conditions for the impact tolerance test of the ZnO valve plate. According to the method, the impact tolerance performance, the aging characteristic and the damage form of the valve plate / lightning arrester can be researched more close to the actual situation, and the failure problem of the lightning arrester can be analyzed.

The embodiment of the invention relates to the field of power systems, and provides a collaborative design scheme generation method and device for submarine cable lightning overvoltage suppression and insulation cooperation based on a particle swarm optimization algorithm, computer equipment and a storage medium, and the method comprises the steps: carrying out the initial configuration of optimization basic data of a to-be-simulated experiment, constructing to obtain a simulation environment after initialization configuration; based on the simulation environment after initialization configuration, parallel electromagnetic transient program simulation is carried out so as to construct a bidirectional coupling framework simulation model of submarine cable lightning overvoltage suppression and insulation cooperation; and based on an improved hybrid particle swarm optimization algorithm, solving the bidirectional coupling framework simulation model to generate a collaborative design scheme corresponding to the submarine cable lightning overvoltage suppression and insulation cooperation process. By adopting the method, the overvoltage level of the submarine cable system and the technical implementation effect of insulation cooperation can be improved, and the safety of the system is improved.

The invention provides a line arrester gap distance correction method and a gap structure thereof, and relates to the technical field of power transmission and distribution primary equipment of a power system. The method for correcting the gap distance of the line lightning arrester comprises the following specific steps: S1, calculating the series gap distance of the lightning arrester according to the 50% discharge voltage of the positive polarity lightning impulse of the lightning arrester with the gap at the altitude of 1000mm and the gap power frequency withstand voltage when the lightning arrester breaks down, and taking the series gap distance as a reference value for correcting the gap distance at different altitudes; by calculating and testing the series gap distance of the line lightning arrester under atmospheric pressure at different altitudes, a correction method for the series gap distance of the line lightning arrester at different altitudes is obtained, reliable action of the series gap distance of the line lightning arrester under lightning overvoltage at different altitudes is ensured, a line insulator is protected, and the service life of the line lightning arrester is prolonged. Line insulator breakdown or flashover is prevented, and the line trip-out rate is reduced; and meanwhile, the maximum power frequency overvoltage occurring in the system can be tolerated.

The invention relates to the technical field of distribution line fault prediction, and provides a distribution line fault prediction method under thunder and lightning influence and related equipment, and the method comprises the steps: determining a plurality of thunder and lightning subareas in a region according to historical thunder and lightning data, and calculating the thunder and lightning tripping probability in each thunder and lightning subarea; calculating an induced lightning stroke overvoltage tripping probability of the target distribution line according to the line data, and calculating a transient fault probability of the target distribution line according to the line data, the historical meteorological data and the historical fault data; calculating the aging failure probability of the target distribution line according to the line data and the historical fault data; and performing fault prediction on the target distribution line based on all the lightning trip probabilities, the inductive lightning overvoltage trip probability, the transient fault probability and the aging failure probability to obtain a fault prediction result of the target distribution line. According to the method, the distribution line fault prediction precision under the lightning influence can be improved.

The embodiment of the invention provides an impact current waveform parameter generation method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring historical lightning stroke parameters; according to the historical lightning stroke parameters and preset topological data, constructing a lightning overvoltage simulation model; executing a simulation operation through the lightning overvoltage simulation model to obtain first internal lightning stroke data of the lightning arrester under different lightning back striking working conditions and second internal lightning stroke data of the lightning arrester under different lightning shielding failure working conditions; and obtaining a plurality of lightning arrester current waveform parameter ranges according to the first internal lightning stroke data and the second internal lightning stroke data. According to the method, the historical lightning stroke parameters and the preset topological data are used for constructing the model for simulation, the influence of different lightning invasion paths on the lightning arrester is comprehensively considered, compared with simulation of a single working condition, the generated waveform parameter range is more accurate, and a more accurate basis is provided for lightning protection design and analysis of a power system.

The invention discloses a VFTO sensor simulation system and method based on an ATP model, and belongs to the technical field of very fast transient overvoltage measurement. The invention provides a simulation system which comprises a model creation module, a parameter setting module, a simulation operation module, an analysis module, a verification module and an optimization module, and aims at solving the problem of lightning overvoltage and VFTO monitoring in a high-voltage-class hydropower station switching station. The system creates a power system and sensor model through an ATP graph or text editor, sets simulation parameters to simulate a VFTO scene, operates simulation to collect sensor output data, analyzes waveform accuracy and sensor performance, and optimizes the sensor and the model based on a result. According to the method, simulation is rapid, monitoring is accurate, the integrity and reliability of VFTO data are effectively improved, and powerful support is provided for power grid optimization; flexible configuration of multiple scenes and multiple parameters is supported, specific requirements of different voltage grades and hydropower stations are met, and scientific basis and technical guarantee are provided for safe and stable operation of a power system.

The present invention discloses a lightning arrester, comprising an insulating tube, both ends of which are sealed with conductive seals, the insulating tube is filled with quartz sand, the quartz sand wraps an arc-starting wire and electrically connects the conductive seals at both ends, one end of the lightning arrester is fixedly connected to a grounding end or a live end via a connector, and the other end forms a discharge gap with the live end or the grounding end, the discharge gap is smaller than the air gap of the insulator, when a lightning overvoltage breaks through the discharge gap, the arc-starting wire fuses to induce an arc to discharge lightning, the arc is suppressed and extinguished by the quartz sand, and line tripping is avoided; compared with the prior art, the lightning arrester has the advantages of small cross-section, light weight, and the length can be manufactured and assembled according to the needs of the installation site, and the overall cost is greatly reduced, so that the lightning arrester can be installed on overhead transmission lines with a large area or even full coverage, thereby greatly reducing the lightning tripping rate and having technical and economic feasibility and practicality.

This invention discloses a clamping method for lightning overvoltage on overhead lines and a combined lightning protection and vibration prevention device. The method includes the following steps: based on the propagation characteristics of lightning waves in a medium, a local impedance abrupt change point is set on the overhead line to alter the propagation process of the lightning wave; wherein, the local lightning wave impedance at the local impedance abrupt change point is less than the overhead line impedance; when the lightning wave reaches the impedance abrupt change point, the voltage wave undergoes negative reflection while the current wave undergoes positive reflection, and the electric field energy of the lightning wave is converted into magnetic field energy, thereby achieving the clamping of the lightning overvoltage. This invention actively clamps lightning overvoltage through impedance transformation and achieves integrated lightning protection and vibration prevention, completely eliminating the dependence of traditional protection on low grounding resistance, effectively reducing the lightning tripping rate while eliminating spatial conflicts and mutual interference between devices.

This utility model discloses a lightning protection power cabinet for new energy applications, belonging to the field of power equipment technology. It includes an outer casing and an inner casing, with the inner casing suspended inside the outer casing. An outer door is rotatably connected to the side of the outer casing, and an inner door is located on the side of the outer door. Several nylon support blocks connect the outer and inner casings, and between the outer and inner doors. The outer and inner doors respectively cover the openings of the outer and inner casings. A connecting frame is installed inside the inner casing near its top. In this design, the outer and inner casings are suspended and separated by nylon support blocks, forming a non-conductive air layer between them. This prevents external lightning current from being directly conducted to the electrical components inside the inner casing. A surge protector is installed on the connecting frame at the top of the inner casing, near the input terminal of the electrical components. It can quickly respond to lightning overvoltages, promptly discharge surge energy, and ultimately provide lightning protection for the electrical components.

The invention discloses a surge lightning stroke overvoltage protection system and a control method thereof. The surge lightning stroke overvoltage protection system comprises a controller, and a second pin of the controller is electrically connected with one end of a sampling resistor, a base electrode of a second triode and a source electrode of a first MOS tube; a third pin of the controller is electrically connected with a collector electrode of a second triode, a collector electrode of a third triode and a grid electrode of a first MOS tube; a first pin of the controller is electrically connected with the emitter of the second triode, the emitter of the third triode and the other end of the sampling resistor and is grounded; the base of the third triode is electrically connected with the emitter of the fourth triode; the collector electrode of the fourth triode is electrically connected with the fifth pin of the controller, the base electrode of the fourth triode is electrically connected with one end of the divider resistor, and the other end of the divider resistor is electrically connected with the fourth pin of the controller and the drain electrode of the first MOS tube. According to the invention, the structure is simple, the occupied space is small, the design difficulty and cost of power electronic products are reduced, and social resources are saved.

This invention discloses a transformer with a lightning protection structure, comprising: an oil tank, windings, an iron core, an integrated lightning protection cover, a grounding structure, a lightning protection conductive plate, and a layered insulation structure. The transformer features a lightning protection cover and lightning-proof protrusion electrically connected to the outer casing at the top of the oil tank, a grounding structure including a grounding base and grounding electrodes at the bottom, and a lightning protection conductive plate connecting the lightning protection cover and the grounding base internally. The plate has conductive contacts that fit against the insulating outer casing of the windings. Multiple layers of insulating sleeves and insulating spacers are provided on the outer side of the windings. This application achieves dual protection against direct and induced lightning strikes through structural optimization, shortens the lightning current conduction path for rapid voltage relief, enhances internal insulation performance, effectively prevents insulation breakdown caused by lightning overvoltage, and improves operational stability.

The invention relates to the field of overvoltage protection devices, and discloses a segmented corner lightning protection overvoltage protection assembly, which comprises a mounting rack, a plurality of mounting plates are fixed on the right side of the mounting rack, protectors are fixed on the top surfaces of the mounting plates, a plurality of connecting plates are fixed on the left side of the mounting rack, and the connecting plates are fixed on the right side of the mounting rack. A lightning arrester is arranged above the connecting plate, current sensors are fixed on the top surface of the connecting plate, a first connecting wire is fixed among the plurality of current sensors, two switches are arranged on the outer wall of the first connecting wire, a ground wire is fixed on the bottom surface of the connecting plate, and a second connecting wire is fixed on the bottom surface of the connecting plate. The second connecting wire is welded with the ground wire, and the other end of the second connecting wire is fixedly provided with a disconnector. According to the invention, through the protection assembly, lightning overvoltage can be effectively dispersed to different grounding paths, impact on a single grounding path is reduced, and subsequent electrical equipment is protected from being damaged by the overvoltage.

The invention discloses an inductive thunder protection method, device and equipment of a wind generating set and a medium, and relates to the field of wind power generation. The maximum value of the second lightning stroke magnetic field intensity corresponding to the second lightning protection area is determined by determining the maximum value of the first positive lightning stroke current, the maximum value of the first negative lightning stroke current and the maximum value of the subsequent lightning stroke current under the preset protection level, and the second lightning protection area comprises the hub internal area of the wind generating set. The induced thunder overvoltage of the wind generating set is also located in the second lightning protection area, so that the induced thunder overvoltage of the power supply line can be determined according to the self-inductance of the power supply line after the maximum value of the second lightning magnetic field intensity is determined, and finally, the lightning protection design scheme of the wind generating set is configured based on the induced thunder overvoltage. And inductive lightning protection is carried out on the wind generating set based on the lightning protection design scheme, and the lightning protection design scheme of the scheme can flexibly adapt to the wind generating sets with different voltage grades and operating environments.

This utility model discloses a repetitive damping lightning suppression line arrester, comprising: a varistor unit for introducing lightning current into the ground; an inductive suppression unit for suppressing sudden changes in lightning current; the varistor unit and the inductive suppression unit are electrically connected and grounded; and a damping suppression unit for adjusting the suppression intensity of the inductive suppression unit according to the intensity of the lightning current, the damping suppression unit being electrically connected to the inductive suppression unit. This solution improves upon the traditional surge arrester based on the nonlinear characteristics of zinc oxide varistors to achieve protection, by setting up an inductive suppression unit to suppress sudden changes in lightning current, and by combining it with a damping suppression unit to adjust the suppression intensity of the inductive suppression unit according to the intensity of the lightning current, effectively suppressing lightning impulse current and protecting power equipment from damage caused by lightning overvoltage.

The present invention relates to the technical field of lightning protection for power transmission and distribution lines, and discloses a method and device for analyzing the distribution of lightning monitoring terminals for multi-branch distribution lines. The present invention constructs a line lightning overvoltage simulation analysis model for a target multi-branch distribution line, constructs a lightning current source model based on the corresponding data of a lightning location system, constructs a corresponding electromagnetic transient model of induced lightning overvoltage based on the two models, and carries out electromagnetic transient simulation to analyze the characteristics and change laws of lightning current waveforms, designs a lightning monitoring terminal distribution scheme that meets the monitoring conditions based on the obtained simulation analysis results and performs simulation verification, and adjusts the distribution position and / or parameters of each lightning monitoring terminal in the scheme according to the simulation verification results, so that each lightning monitoring terminal can meet the preset minimum monitoring requirements. The present invention realizes the optimized design of the lightning monitoring terminal distribution scheme applicable to multi-branch distribution lines, and lays a foundation for the accurate positioning and identification of various lightning faults in multi-branch distribution lines.

The present disclosure relates to a ground wire ice melting insulation coordination design method, device, equipment and medium. The ground wire ice melting insulation coordination design method comprises: determining the direct current required by the ground wire ice melting device for ice melting based on ice melting environment data; determining the direct current voltage at the output end of the ground wire ice melting device based on the direct current and the ground wire ice melting length; determining the operating overvoltage threshold and the lightning overvoltage threshold at the target position corresponding to the ground wire ice melting device based on the direct current voltage; determining the parameters of the lightning arrester based on the operating overvoltage threshold and the lightning overvoltage threshold; and determining the second insulation distance corresponding to the ground wire ice melting device and the ground wire insulator respectively according to the altitude to perform the ground wire ice melting insulation coordination design. Thus, the ground wire ice melting insulation coordination design can ensure the safe and stable operation of the ground wire ice melting device under the conditions of high altitude, heavy ice cover, operating overvoltage and lightning overvoltage.

The utility model discloses a lightning overvoltage protection device of a fan pressure transmitter. The lightning overvoltage protection device comprises a fixing screw, a lightning protection module and a wiring module. The wiring module is installed on one side of the lightning protection module and used for being connected with a ground wire, the lightning protection module is fixedly installed above a fan pressure transmitter through fixing screws, the lightning protection module comprises a shell, a lightning protection plate and inserting pieces, the lightning protection plate and the inserting pieces are installed in the shell, the multiple inserting pieces are installed below the lightning protection plate, and the inserting pieces are connected with the shell. The insertion sheets pass through the housing and are in butt joint with each pin of the fan pressure transmitter. The lightning overvoltage protection device is flexibly and detachably installed and does not need to be installed in the fan in advance, so that the lightning overvoltage protection device is more reasonable in structural design, higher in stability, convenient to install on site and good in lightning protection effect.

This invention discloses a method for protecting against multiple lightning strike overvoltages at an overhead line-DC submarine cable switching station, belonging to the field of lightning overvoltage protection technology. The method includes: establishing an electromagnetic transient simulation model of the overhead line-DC submarine cable switching station; building a lightning current source model; selecting the most stringent waveform and building multiple lightning strike current sources; building a broadband equivalent circuit model of the reactor to simulate the condition of lightning striking a line of the same polarity, and initially determining the reactor inductance value; evaluating whether the reverse polarity lightning impulse overvoltage of the DC submarine cable exceeds the withstand range, and selecting the optimal inductance value that ensures the reverse polarity lightning impulse voltage of the DC submarine cable meets the requirements; optimizing the surge arrester configuration scheme, and selecting the optimal scheme that provides the best overvoltage suppression effect and meets the requirements for surge arrester electrical stress. This invention, using the above method, solves the problem that existing technologies cannot design lightning overvoltage protection schemes for switching stations and submarine cables based on the lightning impulse withstand voltage characteristics of DC submarine cables.

The present invention discloses an intelligent multi-layer gap overvoltage protector based on a copper-chromium alloy material. A multi-layer discharge gap composed of multiple electrodes made of the copper-chromium alloy material is installed in an insulating housing. Each electrode is insulated and isolated by an insulating medium. A trigger electrode is designed at the bottom electrode gap of the multi-layer gap. The trigger electrode can automatically sense and couple to receive the energy of a lightning overvoltage, and trigger the bottom electrode gap of the multi-layer gap and other gaps to conduct quickly. Therefore, the three-terminal overvoltage protection gap of this intelligent multi-layer gap structure has remarkable characteristics such as a high DC breakdown voltage, a high voltage protection level, a fast response time, and a strong ability to resist power frequency or DC follow-up current. This intelligent multi-layer gap overvoltage protector can be used for the protection of direct lightning strikes and lightning-induced overvoltages in application scenarios such as the communication field and even the power field.

The invention discloses a power distribution network lightning overvoltage simplified analysis loop and method, equipment and a medium, and belongs to the technical field of power system overvoltage protection. The loop comprises a lightning current source, a line resistor, a line inductor, a line first ground capacitor and a line second ground capacitor; one end of the lightning current source, one end of the line first ground capacitor and one end of the line resistor are all connected with the common node, the other end of the lightning current source, the other end of the line first ground capacitor and one end of the line second ground capacitor are all grounded, and the other end of the line resistor is connected with one end of the line inductor. The other end of the line inductor is connected with the other end of the second line ground capacitor; the voltage of the common node is the overvoltage of the lightning stroke point. The loop provided by the invention is clear in physical concept and simple in structure, so that a differential equation for describing a physical relationship is deduced based on the loop, an accurate time domain analytical solution expression of the overvoltage of the lightning stroke point is further provided, and a certain basis is provided for safety protection of a distribution line.

The invention provides an ultra-high voltage line lightning arrester service life prediction method and system, and the method comprises the steps: determining a lightning current amplitude interval which causes the action of a line lightning arrester based on the shielding failure lightning resistance level and the maximum shielding failure lightning current of a target power transmission line, which are obtained through calculation based on the obtained electrical parameters and geographic parameters of the target power transmission line; calculating the lightning current occurrence probability corresponding to the lightning current amplitude interval according to the lightning current amplitude probability distribution of the region where the target power transmission line is located, and calculating the lightning current occurrence probability corresponding to the lightning current amplitude interval according to the lightning area of the target power transmission line, the ground lightning density of the region and the lightning current occurrence probability; the predicted lightning stroke overvoltage action times of the lightning arrester installed on the target power transmission line every year are calculated, the electric charge quantity consumed by the lightning arrester under the single lightning stroke overvoltage action is calculated based on the current characteristics of the lightning arrester during action, and then the predicted life of the lightning arrester is calculated based on the predicted lightning stroke overvoltage action times and the electric charge quantity.

The invention provides a wind power plant networking grounding system lightning stroke overvoltage calculation method and system, and the method comprises the steps: calculating the impact grounding impedance and mutual impedance of a grounding device group based on a calculation model of the grounding device group; inputting parameters, and obtaining impact grounding impedance values of all networked fans on the wind power plant through a calculation model; inputting the impact grounding impedance value of the fan at each position of the wind power plant into electromagnetic transient simulation software as a parameter to form a wind power plant networking grounding system; building a multi-wave impedance model of a fan tower in electromagnetic transient simulation software, and forming a lightning stroke overvoltage calculation model of the wind power plant networking grounding system with the wind power plant networking grounding system; and injecting lightning impulse current into the lightning arrester end of the fan blade in the calculation model to obtain lightning stroke voltage values at different positions of the fan. The method is suitable for the complex working condition of actual lightning stroke of the wind power system of the wind network, the lightning stroke overvoltage value can be accurately calculated, and the safety and reliability of a wind power plant unit are improved.

The invention relates to the technical field of flexible direct-current power transmission, in particular to an insulation coordination method of an extra-high voltage flexible direct-current converter station connected to a new energy base, which comprises the following steps of: S1, analyzing a lightning arrester configuration scheme and selecting parameters according to a system main wiring form and an overvoltage characteristic of the converter station; s2, establishing an electromagnetic transient simulation model of the internal overvoltage of the large-scale new energy delivery system, establishing an actual control protection strategy, and establishing a high-frequency transient model of the lightning overvoltage of the extra-high voltage flexible DC converter station connected to the new energy base; s3, internal overvoltage simulation is carried out, and an insulation cooperation scheme is adjusted according to a simulation result; and S4, carrying out lightning verification based on the alternating current side intrusion wave and the direct current side lightning intrusion wave. Through reasonable lightning arrester configuration and parameter optimization, insulation cooperation of the system is realized, influence of transient overvoltage on equipment is effectively reduced, efficient and stable operation of the system is ensured, and equipment cost and engineering construction cost are reduced at the same time.

The present invention discloses a method and device for evaluating a lightning overvoltage waveform. The method comprises: obtaining lightning impulse test waveform data containing oscillations or overshoots, and lightning overvoltage waveform data to be measured containing oscillations or overshoots; constructing a nonlinear system of equations and an algebraic equation based on the lightning impulse test waveform data; calculating a first vector based on the nonlinear system of equations and the algebraic equation in combination with a least squares method; constructing a double exponential model based on the highest component of the first vector and the characteristic root data corresponding to the highest component; inputting the lightning overvoltage waveform data to be measured containing oscillations or overshoots into the double exponential model to obtain an evaluated lightning overvoltage waveform reference curve. The present invention, through a lightning overvoltage waveform evaluation method, effectively determines the parameters of a non-standard lightning overvoltage test wave while avoiding errors in the manual parameter determination process.

This invention discloses a method for identifying lightning overvoltage signals based on wavelet time-frequency maps and an improved CNN, relating to the field of lightning protection technology for power transmission lines. The method includes: acquiring and preprocessing lightning overvoltage waveform data to obtain three-phase time-domain signals; extracting time-frequency features from the three-phase time-domain signals based on continuous wavelet transform and generating a three-phase time-frequency map; performing deep feature mining on the three-phase time-frequency map using a parallel feature extraction network with three pre-trained ResNet branches; weighted fusion of the output features of each branch through compression and attention activation modules; and classifying and outputting the lightning overvoltage type. This invention displays the time-frequency joint distribution characteristics of the retained signal through wavelet time-frequency maps and adaptively extracts deep nonlinear features using an improved multi-channel CNN model, significantly improving the accuracy and robustness of lightning overvoltage type identification.

The invention belongs to the technical field of power systems, and particularly relates to an overvoltage suppression method based on 220kV overhead-cable line lightning overvoltage characteristics. The method comprises the steps that a 220kV overhead-cable mixed line lightning overvoltage simulation model is constructed, the model comprises a mixed line model and a lightning current model, the mixed line model is divided into an overhead line section and a cable line section, and the overhead line model is a JMarti model; the lightning current model adopts a Hardler model, and the lightning current waveform is a double-exponential wave; based on the simulation model, multiple measuring points are arranged on a cable section to collect overvoltage data of a cable core and a sheath, and an overvoltage transmission rule under a lightning stroke working condition is analyzed; aiming at rules, optimizing suppression measures, namely adjusting parameters of a cable terminal lightning arrester, optimizing a sheath protector, and adopting low-resistance grounding to reduce the grounding resistance of a tower; and verifying the effectiveness of the scheme, ensuring that conventional lightning stroke overvoltage control indexes are met, and if not, analyzing and optimizing again until reaching the standard.