Lightning resistance level evaluation method and system of power transmission line

Abstract

The invention is suitable for the technical field of lightning resistance level evaluation, and provides a lightning resistance level evaluation method and system for a power transmission line, and the method comprises the steps: extracting the lightning stroke risk feature information of each tower position according to an obtained basic data set of the power transmission line; generating K risk level classifications; outputting lightning arrester configuration parameters through a lightning arrester configuration model in the lightning resistance level evaluation model; outputting insulation adjustment parameters through an insulation design model in the lightning resistance level evaluation model; selecting L high-risk classifications according to a preset risk threshold condition and lightning arrester configuration parameters; selecting P optimization classifications according to preset insulation constraint conditions and the insulation adjustment parameters; and inputting the lightning arrester configuration parameters and the insulation adjustment parameters in the P optimization classifications into an electromagnetic transient simulation model to generate a lightning resistance level evaluation result. Through high lightning stroke risk tower position / phase protection enhancement and low risk area cost optimization, the trip-out rate and the protection cost are effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lightning withstand level evaluation, and in particular to a lightning withstand level evaluation method and system for a power transmission line. BACKGROUND

[0002] With the rapid growth of high-voltage and extra-high-voltage power transmission lines, line trips and flashover accidents caused by lightning have become one of the important sources of external faults of power systems. Due to the wide coverage and complex terrain of power transmission lines, in areas with frequent lightning activities such as mountains, plateaus, and coastal belts, the probability of lightning strikes on lines is significantly increased, which seriously threatens the power supply reliability and operation safety of the system. Traditional lightning protection measures mainly include adding overhead ground wires, using composite insulators to improve insulation level, configuring line arresters at important tower sites or substation sides, and adopting line insulation coordination. However, these methods have certain limitations, such as high cost and difficult maintenance of uniform configuration of arresters, unreasonable allocation of protection resources without considering the probability of lightning strike and phase difference, and symmetric configuration of insulation strings without fully considering the non-uniformity of terrain, weather, and lightning distribution. These problems can easily lead to resource waste due to excessive configuration of lightning protection equipment in low lightning risk areas, and frequent trip accidents due to insufficient protection in high lightning risk tower sites and outer phases. SUMMARY

[0003] The present application provides a lightning withstand level evaluation method and system for a power transmission line, which solves the problem of resource waste and frequent trip accidents.

[0004] The first aspect of the present application provides a lightning withstand level evaluation method for a power transmission line, comprising: extracting lightning risk feature information of each tower site according to the obtained power transmission line basic data set; generating K risk level classifications based on the lightning risk feature information, wherein K is an integer greater than or equal to 3, and each risk level classification corresponds to a tower site risk subset; outputting arrester configuration parameters corresponding to each risk level classification through an arrester configuration model in the lightning withstand level evaluation model; outputting insulation adjustment parameters corresponding to each risk level classification through an insulation design model in the lightning withstand level evaluation model; selecting L high-risk classifications from the K risk level classifications according to a preset risk threshold condition and the arrester configuration parameters; selecting P optimized classifications from the L high-risk classifications according to a preset insulation constraint condition and the insulation adjustment parameters; Input the arrester configuration parameters and insulation adjustment parameters in the P optimized classifications into an electromagnetic transient simulation model, calculate the lightning trip-out probability and protection cost-benefit ratio of the transmission line, and generate a lightning withstand level evaluation result.

[0005] Further, the K risk level classifications are generated based on the lightning risk feature information, including: According to the historical lightning frequency, geographic elevation weight factor, and meteorological thunderstorm day intensity in the lightning risk feature information, a lightning risk probability value of each tower site is calculated; The lightning risk probability value is divided into K continuous levels by a preset probability threshold interval, and a risk level label is assigned to each tower site to generate a tower site risk subset; The risk level label includes a high risk identifier, a medium risk identifier, and a low risk identifier associated with the arrester configuration parameters.

[0006] Further, Based on the high risk identifier of the risk level classification, a first-level arrester configuration strategy is determined, and rated voltage, current capacity, and operating residual voltage parameters are output; Based on the medium risk identifier of the risk level classification, a second-level arrester configuration strategy is determined, and installation location parameters and current capacity threshold values of single-phase arresters are output; Based on the low risk identifier of the risk level classification, configuration parameters of an arrester monitoring unit are output.

[0007] Further, the arrester configuration parameters corresponding to each risk level classification are output by an arrester configuration model in the lightning withstand level evaluation model, further including: The execution of the first-level arrester configuration strategy includes: performing three-phase full configuration of metal oxide arresters on corner towers, crossing towers, and line end towers; The execution of the second-level arrester configuration strategy includes: calculating installation location parameters based on tower site electrical distance and ground potential change gradient, and performing differential installation of single-phase arresters for outside phases or high lightning phases; The generation of the arrester monitoring unit configuration parameters includes: associating with the lightning protection demand of the induction lightning protection to configure a communication interface, and reserving extension protocol compatibility.

[0008] Further, the insulation adjustment parameters corresponding to each risk level classification are output by an insulation design model in the lightning withstand level evaluation model, including: Based on the high risk identifier of the risk level classification, insulation enhancement parameters for high risk phases are output; Based on the low risk identifier of the risk level classification, insulation weakening parameters for low risk phases are output; Output the overall insulation coordination constraint parameter to ensure that the insulation distance of each phase is not lower than the preset phase-to-ground impulse withstand distance.

[0009] Further, the output of the insulation design model in the lightning withstand level evaluation model includes: The execution of the insulation enhancement parameter includes increasing the number of insulators, using a composite umbrella skirt enhanced insulator, or a superimposed epoxy rod structure. The execution of the insulation weakening parameter includes reducing the number of insulators, and the reduced creepage distance is not lower than the original design value. The verification of the overall insulation coordination constraint parameter includes simulating the voltage distribution uniformity, the synthesized withstand voltage characteristics, and the pollution flashover probability.

[0010] Further, the selection of L high-risk classifications from the K risk level classifications according to the preset risk threshold condition and the arrester configuration parameter includes: Determine whether the configuration level in the arrester configuration parameter belongs to a first-level full protection strategy. If it belongs to a first-level full protection strategy, the risk level classification corresponding to the configuration level is included in the L high-risk classifications. If it does not belong to a first-level full protection strategy, calculate the arrester protection efficiency value of the risk level classification corresponding to the configuration level and the cost threshold of the preset risk threshold condition; when the protection efficiency value is lower than the threshold and the cost exceeds the preset upper limit, the risk level classification corresponding to the configuration level is filtered out of the L high-risk classifications.

[0011] Further, the selection of P optimization classifications from the L high-risk classifications according to the preset insulation constraint condition and the insulation adjustment parameter includes: Extract the insulation enhancement parameter and the insulation weakening parameter in the insulation adjustment parameter. Determine whether the insulation enhancement parameter satisfies the upper limit of the insulation increment in the preset insulation constraint condition; and determine whether the insulation weakening parameter satisfies the lower limit of the creepage distance in the preset insulation constraint condition. The high-risk classification that simultaneously satisfies the upper limit of the insulation increment and the lower limit of the creepage distance is included in the P optimization classifications.

[0012] Further, the input of the arrester configuration parameter and the insulation adjustment parameter in the P optimization classifications into the electromagnetic transient simulation model, the calculation of the lightning trip-out probability of the transmission line and the protection cost-benefit ratio, and the generation of the lightning withstand level evaluation result include: Based on the arrester configuration parameter and the insulation adjustment parameter, an electromagnetic transient simulation model is constructed, which includes the arrester volt-ampere characteristic, the insulator flashover characteristic, and the line distributed parameter. injecting a standard lightning current waveform into the electromagnetic transient simulation model, solving the conduction path and shunt efficiency of the lightning current in the power transmission line; According to the solving result, the impulse flashover times of the insulator string are counted, and a lightning trip-out probability value of the whole line is generated; Combining the purchase cost of the arrester, the insulation adjustment cost and the lightning trip-out loss, the cost-benefit ratio of the protection measure is calculated.

[0013] The second aspect of the present application provides a lightning withstand level evaluation system of a power transmission line, comprising: A lightning risk feature information extraction unit is configured to extract lightning risk feature information of each tower site according to the obtained power transmission line basic data set; A risk level classification generation unit is configured to generate K risk level classifications based on the lightning risk feature information, wherein K is an integer greater than or equal to 3, and each risk level classification corresponds to a tower site risk subset; An arrester configuration parameter output unit is configured to output the arrester configuration parameters corresponding to each risk level classification through an arrester configuration model in the lightning withstand level evaluation model; An insulation adjustment parameter output unit is configured to output the insulation adjustment parameters corresponding to each risk level classification through an insulation design model in the lightning withstand level evaluation model; A high-risk classification determination unit is configured to select L high-risk classifications from the K risk level classifications according to a preset risk threshold condition and the arrester configuration parameters; An optimized classification determination unit is configured to select P optimized classifications from the L high-risk classifications according to a preset insulation constraint condition and the insulation adjustment parameters; A lightning withstand level evaluation result generation unit is configured to input the arrester configuration parameters and the insulation adjustment parameters in the P optimized classifications into an electromagnetic transient simulation model, calculate the lightning trip-out probability and the protection cost-benefit ratio of the power transmission line, and generate a lightning withstand level evaluation result.

[0014] As can be seen from the above technical solutions, the present application has the following advantages: The application divides the tower positions of the whole line into K risk level classifications according to the lightning stroke risk features extracted from the power transmission line basic data set, each classification corresponds to a tower position risk subset, which helps to accurately describe the lightning stroke risk image; the lightning arrester configuration model outputs three-phase full protection parameters for the high risk subset, single-phase optimization parameters for the medium risk subset, and only configures a monitoring unit for the low risk subset, avoiding equipment redundancy in the low risk area; the insulation design model enhances the insulation of the high risk phase and appropriately weakens the low risk phase, which can reduce mechanical overload and insufficient protection caused by symmetrical insulation; L high risk classifications are selected from K classifications through risk threshold conditions to eliminate inefficient and high consumption schemes; P optimization classifications are selected from L classifications based on insulation constraints to block the risk of insulation imbalance; finally, the P class parameters are input into the electromagnetic transient model to calculate the trip-out probability and cost-benefit ratio, so that the protection scheme meets the technical and economic standards. Through high lightning stroke risk tower positions, phase-specific protection reinforcement and low risk area cost optimization, the application can improve resource utilization while reducing the occurrence of fault events. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 An embodiment flowchart of a lightning level evaluation method for a power transmission line in the application; Fig. 2 Another embodiment flowchart of a lightning level evaluation method for a power transmission line in the application; Fig. 3 Another embodiment flowchart of a lightning level evaluation method for a power transmission line in the application; Fig. 4 Another embodiment flowchart of a lightning level evaluation method for a power transmission line in the application. DETAILED DESCRIPTION

[0016] The terms "first", "second", "third", "fourth" and the like used in the description of the application and the above drawings, if any, are used to distinguish similar objects, and do not necessarily have to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "correspond to" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] Embodiment one The method implemented in this embodiment can be implemented in a system, can be implemented in a server, or can be implemented in a terminal, and the specific implementation is not limited. From the perspective of system implementation, the method for evaluating the lightning withstand level of the power transmission line in the present application will be introduced. Please refer to Figs. 1 to 4 The method provided in the embodiment of the present application includes the following steps: 101. Extract lightning risk feature information of each tower site according to the obtained power transmission line basic data set; This step constructs a lightning risk feature space of the power transmission line by fusing multi-source heterogeneous data. First, the time and space dimensions of the power transmission line basic data set are aligned, and the data set includes historical lightning data (time / intensity / polarity), geographic elevation information (elevation / slope), meteorological parameters (thunderstorm day distribution), and tower site structure (tower height / phase spacing). The spatial interpolation modeling technology is used to generate a tower site level lightning probability distribution map. Specifically, the discrete lightning point data is converted into a continuous risk surface by the inverse distance weighted algorithm, and the joint probability is calibrated in combination with the environmental factors. The feature extraction process distinguishes between real-time features and offline features, i.e., the current thunderstorm activity intensity and the annual average lightning frequency, wherein the offline features include the recent lightning search state. Finally, the structured feature vector is output as: , wherein is the real-time lightning probability, is the recent lightning search state, is the elevation weight factor, is the meteorological intensity coefficient, is the tower site structure risk coefficient.

[0018] 102. Based on the lightning risk feature information, K risk level classifications are generated, wherein K is an integer greater than or equal to 3, and each risk level classification corresponds to a tower site risk subset; Generating the risk level classification can include the following steps: 201. According to the historical lightning frequency, the geographic elevation weight factor, and the meteorological thunderstorm day intensity in the lightning risk feature information, the lightning risk probability value of each tower site is calculated; The weighted fusion model is used to calculate the lightning risk probability value of the tower site : , wherein: is the historical lightning frequency, is the geographic elevation weight factor, and the slope > 25° is taken as 1.8, is the meteorological thunderstorm day intensity (annual average thunderstorm day / maximum value), and the weight coefficient is distributed according to the contribution, = 0.4, = 0.3, = 0.3, and the proportion is determined by regression analysis of 10,000 line samples.

[0019] 202. Divide the probability value of lightning strike risk into K consecutive levels by a preset probability threshold range, and assign a risk level label to each tower location to generate a risk subset of the tower location; wherein, the risk level label includes a high-risk label, a medium-risk label, and a low-risk label associated with the configuration parameters of the surge arrester.

[0020] Three levels of labels are defined based on preset probability threshold ranges: High-risk label: [0.85, 1.0], set based on: tripping probability > 5% for this interval (based on IEEE Std 1243 lightning strike fault statistics); medium risk indicator: [0.65, 0.85), set based on: tripping probability of 1%~5% and controllable equipment damage costs; low-risk indicator: [0,0.65)$, set based on the tolerance threshold of tripping probability <1%.

[0021] Used based on lightning strike risk probability value Give tower position Assign risk level labels Formalization: Enter a single tower location Corresponding probability of lightning strike , ,according to The system determines which interval a value falls into and outputs a corresponding discrete label (high, medium, or low risk indicator). Essentially, it converts continuous probability values ​​into their corresponding discrete labels. Mapping to discrete risk levels facilitates subsequent classification and processing of tower sites according to risk level.

[0022] The three risk subsets are defined using set comprehensions, the core of which is to select all tower sites that meet the corresponding risk labels. Formalized as follows: High-risk subset Medium-risk subset Low-risk subset .

[0023] 103. Using the surge arrester configuration model in the lightning resistance level assessment model, output the surge arrester configuration parameters corresponding to each risk level classification; Determining the surge arrester configuration parameters can be achieved through the following steps: 301. Based on the high-risk identification of risk level classification, determine the configuration strategy of primary surge arrester and output rated voltage, current capacity and operating residual voltage parameters; 302. Based on the medium-risk identification of risk level classification, determine the configuration strategy of secondary surge arresters, and output the installation location parameters and current capacity threshold of single-phase surge arresters; 303. Low-risk identification based on risk level classification, output configuration parameters of the arrester monitoring unit.

[0024] Primary arrester configuration strategy: For the corner towers, crossing towers and line end towers with the highest lightning risk in the transmission line, three-phase full configuration of metal oxide arresters is uniformly implemented, and the rated voltage, flow capacity and operating residual voltage parameters are output. All parameters are verified to meet the mandatory protection standards of key lines in DL / T 620-2021. For example, the corner tower numbered TA-21 in a certain 500kV line project is marked as high risk identification due to the electric field distortion formed by the wire corner, triggering the primary strategy. The system automatically outputs the rated voltage of 715kV (1.3 times the system highest operating voltage of 550kV), the flow capacity of 40kA (satisfying the multiple lightning protection requirements), and the operating residual voltage of 580kV (lower than 2.5 times the insulator flashover voltage).

[0025] Secondary arrester configuration strategy: Based on the calculation of the electrical distance and the ground potential gradient of the tower position, differential installation of single-phase arrester is performed for the outer phase or high lightning phase, and the installation coordinates and flow capacity threshold are output. For example, the risk tower position TB-07 in a certain 220kV line is located in a hilly and steep slope area, the electrical distance calculation value is 12.7 meters, and the ground potential gradient detection reaches 18kV / m, triggering the position offset mechanism. The final installation point is determined to be 3.8 meters away from the tower base on the outer phase C phase, and the flow capacity threshold is set to 32kA (terrain weighting value).

[0026] Correlation lightning protection requirement configuration communication interface and reserved expansion protocol compatibility, dual-mode communication design makes the appearance of the monitoring unit consistent with the arrester body. For example, when the low-risk tower position TC-33 is configured with the monitoring unit, the RS-485 and IEC 61850 dual-protocol interfaces are output, the sampling frequency of 10MHz can completely capture the 1μs lightning current wave head, the shell is multiplexed with the standard arrester structure and the GPIO-12 pin is reserved, and the field inspection cannot distinguish the real arrester through the appearance.

[0027] Among them, the execution of the primary arrester configuration strategy includes: performing three-phase full configuration of metal oxide arresters on corner towers, crossing towers and line end towers; the execution of the secondary arrester configuration strategy includes: calculating the installation position parameters based on the electrical distance and the ground potential gradient of the tower position, and performing differential installation of single-phase arrester for the outer phase or high lightning phase; the generation of the arrester monitoring unit configuration parameters includes: configuring the communication interface associated with the lightning protection requirement, and reserving the expansion protocol compatibility.

[0028] Specifically, the execution of the first-level lightning arrester configuration strategy is to forcibly implement three-phase full configuration of metal oxide lightning arresters for the tower at the corner of the conductor due to the distortion of the electric field distribution, the crossing tower with significantly expanded lightning shielding range due to the increase in tower height, and the tower position prone to discharge due to the sudden change of wave impedance at the end of the line. The second-level lightning arrester configuration strategy is to determine the installation position of the single-phase lightning arrester based on the electrical distance of the tower position (calculated based on the tower height, soil resistivity, and down conductor size) and the ground potential gradient (when the gradient value exceeds 15 kV / m in the steep slope area, the deviation mechanism is triggered), and the single-phase lightning arrester is preferentially deployed on the outer phase with the highest historical lightning strike frequency. The generation of the configuration parameters of the lightning arrester monitoring unit is to associate the lightning protection requirements to configure a dual-mode communication interface (RS-485 transmission of real-time sampling data and IEC 61850 protocol support for remote encrypted monitoring), while reserving a physical expansion interface to realize protocol compatibility, and to realize hidden deployment by multiplexing the lightning arrester body shell structure.

[0029] 104. Through the insulation design model in the lightning resistance level evaluation model, output the insulation adjustment parameters corresponding to each risk level classification; In this embodiment, based on the above steps, the output insulation adjustment parameters include: based on the high-risk identification of the risk level classification, output the insulation enhancement parameters of the high-risk phase; based on the low-risk identification of the risk level classification, output the insulation weakening parameters of the low-risk phase; output the overall insulation coordination constraint parameters to ensure that the insulation distance of each phase is not less than the preset phase-to-ground impulse withstand distance.

[0030] Wherein, the execution of the insulation enhancement parameters includes: increasing the number of insulators, using composite umbrella skirt enhanced insulators or superimposed epoxy rod structure; the execution of the insulation weakening parameters includes: reducing the number of insulators, and the reduced creepage distance is not less than the original design value; the verification of the overall insulation coordination constraint parameters includes: through simulation analysis of voltage distribution uniformity, synthesized withstand voltage characteristics and pollution flashover probability.

[0031] 1. For the high-risk identification phase, the insulation enhancement operation is realized by increasing the number of insulators, using composite umbrella skirt enhanced insulators or superimposed epoxy rod structure, and the specific selection is based on the dynamic decision of terrain slope and pollution level: when the terrain slope exceeds 25°, the superimposed epoxy rod structure is forced to be used to improve the mechanical bending strength; when the pollution level reaches E3 level or above, the composite umbrella skirt enhanced insulator is switched to suppress pollution flashover by using the high hydrophobicity of silicone rubber material; in the conventional scene, the number of porcelain insulators is increased, the string length increase is strictly controlled in the interval of 10%-25%, the safety factor of the insulator string hardware holding force is not less than 2.8, and the newly added insulator number needs to pass the finite element analysis to verify its deformation margin under extreme wind load.

[0032] 2. When insulation weakening is performed on low-risk identification, start the creeping distance guarantee mechanism in the process of reducing the number of insulator sheds: calculate the equivalent creepage coefficient k based on the insulator shed structure type (bell type / double umbrella type), dynamically adjust the upper limit of the number of reduced sheds through a geometric optimization model, and ensure that the creeping distance after weakening is neither lower than the minimum value specified in the national standard nor lower than 95% of the original design value, wherein the bell type insulator takes k=1.8 due to the advantage of the umbrella skirt inclination angle, and the double umbrella type takes k=1.5, and the coefficient is derived from the critical flashover gradient curve under the condition of salt density 0.1 mg / cm2 in the pollution test.

[0033] 3. After outputting the insulation adjustment parameters, verify the overall coordination by using multi-physical field coupling simulation: calculate the voltage sharing rate of each insulator shed by static electric field finite element analysis, and require that the difference between the maximum value and the minimum value is less than 15% to ensure the uniformity of voltage distribution; inject a standard lightning impulse wave (1.2 / 50 μs) to obtain the combined withstand voltage characteristic, and verify that the 50% impulse flashover voltage value of the adjusted insulator string is higher than 1.2 times the basic impulse insulation level of the line; combined with the on-site equivalent salt density measurement data, call the Obenaus pollution flashover model to calculate the critical flashover gradient, and require that the pollution flashover probability is always lower than the 0.1% threshold of the hundred-year failure rate.

[0034] 105. Select L high-risk classifications from K risk level classifications according to a preset risk threshold condition and the arrester configuration parameters; In this embodiment, it is determined whether the configuration level in the arrester configuration parameters belongs to the first-level full protection strategy; if it belongs to the first-level full protection strategy, the risk level classification corresponding to the configuration level is included in the L high-risk classifications; if it does not belong to the first-level full protection strategy, the arrester protection efficiency value of the risk level classification corresponding to the configuration level is calculated and compared with the cost threshold of the preset risk threshold condition; when the protection efficiency value is lower than the threshold and the cost exceeds the preset upper limit, the risk level classification corresponding to the configuration level is filtered out of the L high-risk classifications.

[0035] Specifically, first, the strategy level in the arrester configuration parameters is identified; if it is a first-level full protection strategy, that is, a three-phase full configuration for the corner tower, the crossing tower and the line end tower, the risk level classification bound to this strategy is directly included in the L high-risk set; if it is not a first-level strategy, an economic filtering model is started, and the arrester protection efficiency value and the cost threshold of the classification are dynamically calculated; the protection efficiency value is calibrated according to the proportion of the arrester shunt capacity to the designed lightning current, combined with the terrain slope correction factor; the cost threshold is determined by a dynamic upper limit according to the regional economic coefficient, the single tripping loss and the basic tripping probability; when the protection efficiency value is lower than the industry critical value of 0.75 and the actual cost exceeds the dynamic threshold at the same time, the classification is removed from the candidate set; the finally output L high-risk classification ensures that the forced protection target and the economic optimal solution are covered at the same time.

[0036] 106. Selecting P optimization classifications from L high-risk classifications according to preset insulation constraints and the insulation adjustment parameters; Specifically, first, the enhancement ratio (representing the increase in the length of the high-risk phase insulator string) and the reduced creepage distance (representing the low-risk phase insulation reduction index) in the insulation adjustment parameters are extracted, and it is verified whether the enhancement ratio meets the upper limit constraint of the insulation increase, and whether the reduced creepage distance meets the double protection constraint of the creepage distance, that is, the reduced creepage distance is neither lower than the minimum value specified in the national standard GB 50545 nor lower than 95% of the original design value, to prevent the flashover probability from sharply increasing under the conditions of contamination or icing. Only when the high-risk classification passes the above two conditions at the same time, the insulation design scheme is included in the P optimization classification, ensuring that the asymmetric insulation adjustment does not cause mechanical overload or external insulation failure risk while improving the lightning withstand level.

[0037] 107. Inputting the arrester configuration parameters and the insulation adjustment parameters in the P optimization classifications into an electromagnetic transient simulation model to calculate the lightning trip-out probability of the transmission line and the cost-benefit ratio of the protection, and generating the lightning withstand level evaluation result.

[0038] The simulation process includes the following steps: 701. Building an electromagnetic transient simulation model based on the arrester configuration parameters and the insulation adjustment parameters, the model including the arrester voltage-current characteristic, the insulator flashover characteristic, and the line distributed parameter; 702. Injecting a standard lightning current waveform into the electromagnetic transient simulation model to solve the conduction path and the shunt efficiency of the lightning current in the transmission line; 703. According to the solving result, counting the impulse flashover times of the insulator string to generate the lightning trip-out probability value of the whole line; 704. Combining the arrester procurement cost, the insulation adjustment cost, and the lightning trip-out loss to calculate the cost-benefit ratio of the protection measures.

[0039] Based on the arrester configuration parameters and the insulation adjustment parameters of the optimization classification, an electromagnetic transient simulation model is built, which integrates the nonlinear voltage-current characteristic curve of the arrester, the impulse flashover characteristic of the insulator string, and the distributed wave impedance parameter of the transmission line. A standard lightning current waveform with a wave head time of 1.2 microseconds and a wave tail time of 50 microseconds is injected into the model, and the conduction path and the arrester shunt efficiency of the lightning current in the transmission line are simulated through numerical solving algorithm. According to the simulation result, the impulse flashover times of the insulator string of the whole line are determined, and the lightning trip-out probability value in the percentage system is generated by dividing the total flashover times by the lightning simulation times. Finally, the cost-benefit ratio of the protection measures is calculated by combining the arrester procurement cost, the insulation modification cost, and the power loss caused by the lightning trip-out, which is the trip-out probability reduction amplitude multiplied by the economic loss of single trip-out and divided by the total protection investment. When the trip-out probability is lower than 0.5% and the cost-benefit ratio is greater than 3.0, the lightning withstand level standard evaluation conclusion is output.

[0040] Embodiment two An embodiment of the lightning withstand level evaluation system of a power transmission line includes the following steps: A lightning strike risk feature information extraction unit is configured to extract lightning strike risk feature information of each tower site according to the obtained power transmission line basic data set; A risk level classification generation unit is configured to generate K risk level classifications based on the lightning strike risk feature information, where K is an integer greater than or equal to 3, and each risk level classification corresponds to a tower site risk subset; A lightning arrester configuration parameter output unit is configured to output lightning arrester configuration parameters corresponding to each risk level classification through a lightning arrester configuration model in the lightning withstand level evaluation model; An insulation adjustment parameter output unit is configured to output insulation adjustment parameters corresponding to each risk level classification through an insulation design model in the lightning withstand level evaluation model; A high-risk classification determination unit is configured to select L high-risk classifications from the K risk level classifications according to a preset risk threshold condition and the lightning arrester configuration parameters; An optimized classification determination unit is configured to select P optimized classifications from the L high-risk classifications according to a preset insulation constraint condition and the insulation adjustment parameters; A lightning withstand level evaluation result generation unit is configured to input the lightning arrester configuration parameters and the insulation adjustment parameters in the P optimized classifications into an electromagnetic transient simulation model, calculate a lightning trip-out probability and a protection cost-benefit ratio of the power transmission line, and generate a lightning withstand level evaluation result.

[0041] The specific limitations of the system can be referred to the limitations of the method described above, which will not be repeated here. Each module in the above system can be realized by software, hardware, and their combinations. The above modules can be embedded in or independent of the processor in the computer device in hardware form, or stored in the memory in the computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0042] It can be understood that those skilled in the art can combine various embodiments in the above embodiments to obtain technical solutions of various embodiments.

[0043] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for assessing the lightning withstand level of a transmission line, characterized in that, include: Based on the obtained basic dataset of transmission lines, lightning strike risk characteristics of each tower location are extracted; Based on the lightning strike risk characteristics, K risk level classifications are generated, where K is an integer greater than or equal to 3, and each risk level classification corresponds to a subset of tower location risks. Using the surge arrester configuration model in the lightning resistance level assessment model, output the surge arrester configuration parameters corresponding to each risk level classification; Using the insulation design model in the lightning resistance level assessment model, output the insulation adjustment parameters corresponding to each risk level classification; Based on the preset risk threshold conditions and the surge arrester configuration parameters, select L high-risk categories from the K risk level categories; Based on the preset insulation constraints and the insulation adjustment parameters, select P optimized categories from the L high-risk categories; Input the surge arrester configuration parameters and insulation adjustment parameters from the P optimized classifications into the electromagnetic transient simulation model, calculate the lightning trip probability and protection cost-effectiveness ratio of the transmission line, and generate the lightning withstand level assessment results.

2. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, Based on the lightning strike risk characteristic information, K risk level classifications are generated, including: Based on the historical lightning strike frequency, geographical elevation weighting factor, and meteorological thunderstorm intensity in the lightning strike risk characteristic information, the lightning strike risk probability value of each tower location is calculated. The lightning strike risk probability value is divided into K consecutive levels by using a preset probability threshold range, and a risk level label is assigned to each tower location to generate a tower location risk subset; The risk level labels include high-risk, medium-risk, and low-risk labels associated with the surge arrester configuration parameters.

3. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, The surge arrester configuration model in the lightning resistance level assessment model outputs surge arrester configuration parameters corresponding to each risk level classification, including: Based on the high-risk identification of the risk level classification, the configuration strategy of the primary surge arrester is determined, and the rated voltage, current capacity and operating residual voltage parameters are output. Based on the medium-risk label of the risk level classification, the configuration strategy of the secondary surge arrester is determined, and the installation location parameters and current capacity threshold of the single-phase surge arrester are output. Based on the low-risk identifier of the risk level classification, the configuration parameters of the surge arrester monitoring unit are output.

4. The method for assessing the lightning withstand level of transmission lines according to claim 3, characterized in that, The step of outputting the surge arrester configuration parameters corresponding to each risk level classification through the surge arrester configuration model in the surge resistance level assessment model also includes: The implementation of the primary surge arrester configuration strategy includes: applying three-phase full-configuration metal oxide surge arresters to angle towers, crossing towers, and line end towers; The execution of the secondary surge arrester configuration strategy includes: calculating the installation location parameters based on the tower location electrical distance and ground potential change gradient, and performing differentiated installation of single-phase surge arresters for the outer phase or the high lightning strike phase; The generation of configuration parameters for the surge arrester monitoring unit includes: configuring the communication interface for the associated induced lightning protection requirements, and reserving compatibility for extended protocols.

5. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, The insulation design model in the lightning resistance level assessment model outputs insulation adjustment parameters corresponding to each risk level classification, including: Based on the high-risk identifier of the risk level classification, the insulation enhancement parameters of the high-risk phase are output; Based on the low-risk identifier of the risk level classification, the insulation weakening parameters of the low-risk phase are output; Output overall insulation coordination constraint parameters to ensure that the insulation distance of each phase is not lower than the preset phase-to-ground impulse withstand distance.

6. The method for assessing the lightning withstand level of transmission lines according to claim 5, characterized in that, The method of outputting insulation adjustment parameters corresponding to each risk level classification through the insulation design model in the lightning resistance level assessment model also includes: The implementation of the insulation enhancement parameters includes: increasing the number of insulator discs, using composite shed-reinforced insulators or superimposed epoxy rod structures; The implementation of the insulation weakening parameters includes: reducing the number of insulator discs, and ensuring that the creepage distance after the reduction is not lower than the original design value; The verification of the overall insulation coordination constraint parameters includes: analyzing voltage distribution uniformity, composite withstand voltage characteristics, and pollution flashover probability through simulation.

7. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, The step of selecting L high-risk categories from the K risk level categories according to the preset risk threshold conditions and the surge arrester configuration parameters includes: Determine whether the configuration level in the surge arrester configuration parameters belongs to the first-level full protection strategy; If it belongs to the Level 1 full protection strategy, then the risk level classification corresponding to the configuration level will be included in the L high-risk classification; If it does not belong to the first-level full protection strategy, the surge arrester protection efficiency value of the risk level classification corresponding to the configuration level is calculated and the cost threshold of the preset risk threshold condition is calculated; when the protection efficiency value is lower than the threshold and the cost exceeds the preset upper limit, the risk level classification corresponding to the configuration level is filtered out as the L high-risk classification.

8. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, The step of selecting P optimized categories from the L high-risk categories according to the preset insulation constraint conditions and the insulation adjustment parameters includes: Extract the insulation enhancement parameters and insulation reduction parameters from the insulation adjustment parameters; Determine whether the insulation enhancement parameter meets the upper limit of the insulation increase in the preset insulation constraint conditions; at the same time, determine whether the insulation weakening parameter meets the lower limit of the creepage distance in the preset insulation constraint conditions. High-risk categories that simultaneously meet the upper limit of insulation increase and the lower limit of creepage distance are included in the P-optimized classification.

9. The method for assessing the lightning withstand level of transmission lines according to claim 1, characterized in that, The process involves inputting the surge arrester configuration parameters and insulation adjustment parameters from the P optimized classifications into the electromagnetic transient simulation model to calculate the lightning trip probability and protection cost-effectiveness ratio of the transmission line, generating a lightning withstand level assessment result, including: An electromagnetic transient simulation model is constructed based on the surge arrester configuration parameters and insulation adjustment parameters. The electromagnetic transient simulation model includes the surge arrester volt-ampere characteristics, insulator flashover characteristics, and line distributed parameters. A standard lightning current waveform is injected into the electromagnetic transient simulation model to solve the conduction path and shunting efficiency of the lightning current in the transmission line. Based on the solution results, the number of impulse flashovers of the insulator strings is counted, and the probability value of lightning tripping of the entire line is generated. Calculate the cost-effectiveness ratio of protective measures by combining the purchase cost of surge arresters, insulation adjustment costs, and lightning tripping losses.

10. A lightning withstand level assessment system for transmission lines, characterized in that, include: The lightning strike risk feature information extraction unit is used to extract the lightning strike risk feature information for each tower location based on the acquired basic data set of the transmission line. The risk level classification generation unit is used to generate K risk level classifications based on the lightning strike risk characteristic information, wherein K is an integer greater than or equal to 3, and each risk level classification corresponds to a subset of tower location risks; The surge arrester configuration parameter output unit is used to output the surge arrester configuration parameters corresponding to each risk level classification through the surge arrester configuration model in the surge resistance level assessment model; The insulation adjustment parameter output unit is used to output the insulation adjustment parameters corresponding to each risk level classification through the insulation design model in the lightning resistance level assessment model. The high-risk classification determination unit is used to select L high-risk categories from the K risk level categories according to preset risk threshold conditions and the surge arrester configuration parameters; The optimization classification determination unit is used to select P optimized classifications from the L high-risk classifications according to preset insulation constraint conditions and the insulation adjustment parameters; The lightning withstand level assessment result generation unit is used to input the surge arrester configuration parameters and insulation adjustment parameters from the P optimized classifications into the electromagnetic transient simulation model, calculate the lightning trip probability and protection cost-effectiveness ratio of the transmission line, and generate the lightning withstand level assessment result.

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