Method, device and equipment for evaluating multiple lightning stroke waveform parameters of power transmission line

Abstract

The invention discloses a power transmission line multiple lightning stroke waveform parameter evaluation method, device and equipment, and relates to the technical field of ultra-high voltage power transmission line design. Lightning stroke modes are divided into counterattack and shielding failure, the lightning resistance level and the lightning stroke amplitude when lightning directly counterattack a line are obtained, and meanwhile the lightning shielding failure condition is specifically analyzed; according to the method, the critical current when the line is shielded by the lightning and the lightning resistance level of a lightning stroke tower are analyzed, and the critical current when the line is shielded by the lightning and the lightning resistance level are compared to obtain the lightning current amplitude of the line under the actual condition of the line. The lightning is divided into direct counterattack and shielding failure, and the lightning current amplitude during lightning shielding failure of the line is mainly analyzed, so that the analysis condition is closer to the actual condition of the line, the captured lightning current is complete and low in distortion degree, and the evaluation accuracy of multiple lightning stroke waveform parameters is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high voltage transmission line design, and in particular to a method, device and equipment for evaluating multiple lightning waveform parameters of a transmission line. Background Art

[0002] Lightning strikes on ultra-ultra-high voltage AC transmission lines, especially multiple continuous lightning strikes in a short period of time, are an important cause of system tripping. Compared with single lightning strikes, the waveform parameters of multiple lightning strikes are complex and changeable, and there is no standardized basis for conducting lightning overvoltage analysis. Therefore, for the actual working conditions of ultra-ultra-high voltage lines, determining the parameters of multiple lightning strikes and supporting external overvoltage calculations are crucial to the system insulation coordination and lightning arrester configuration, and are the hot spots and difficulties of current research.

[0003] Lightning monitoring data show that the waveform parameters of multiple lightning strikes are highly random and each lightning strike is different. Using uniform multiple lightning strike parameters for simulation calculations often cannot prove whether the system can withstand multiple lightning strikes, and thus cannot test the robustness of the system. It is not completely suitable for the system insulation coordination design in the design phase. Moreover, lightning strike accidents in power systems are sporadic and only reflect the overvoltage level of the actual fault process based on a single lightning current standard.

[0004] At present, the calculation method of multiple lightning waveform parameters is mainly based on actual observation data at home and abroad. Many observation sites are arranged abroad to measure lightning current waveform and other information, such as monitoring on buildings or specially set up observation stations. Some install monitoring devices on UHV transmission lines to collect lightning current waveforms struck on towers. In the early days, magnetic steel rods were mainly used to measure lightning current amplitude on transmission lines. In recent years, researchers have carried out a large number of transmission line lightning current waveform measurements. However, due to the sampling rate, recording time and other factors of lightning current sensors, the directly captured lightning currents often have large distortion, and the captured lightning current parameters are messy and not representative. Therefore, the current means of assessing multiple lightning waveform parameters have low accuracy, and it is difficult to provide specific guidance for the design of ultra-ultra-high voltage AC transmission lines. Summary of the invention

[0005] The embodiments of the present invention provide a method, device and equipment for evaluating multiple lightning stroke waveform parameters of a power transmission line, which can solve the problem in the prior art that the current means used to evaluate multiple lightning stroke waveform parameters have low accuracy.

[0006] The embodiment of the present invention provides a method for evaluating waveform parameters of multiple lightning strikes on a power transmission line, comprising the following steps:

[0007] Obtain the lightning resistance level and lightning amplitude of the lightning tower when the lightning strikes the line;

[0008] According to the EGM strike distance theory, the critical current amplitude of the shielding strike when the lightning strikes the line is obtained; according to the critical current amplitude of the shielding strike, the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth are obtained; according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, the protection angle of the lightning conductor is obtained, and the critical strike distance is obtained using the protection angle of the lightning conductor;

[0009] According to the critical current amplitude of shielding failure, the lightning strike distance to the ground wire, the lightning strike distance to the conductor, the lightning strike distance to the earth and the critical strike distance, the critical current when the lightning shielding fails to pass the line is obtained; according to the critical current when the lightning shielding fails to pass the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning shielding fails to pass the line;

[0010] When the lightning withstand level when lightning strikes the line is greater than the critical current, the lightning withstand level is classified as the lightning current amplitude; when the lightning withstand level is less than the critical current, the lightning withstand level and the critical current amplitude are simultaneously classified as the lightning current amplitude;

[0011] The lightning strike amplitude when lightning strikes the line and the lightning current amplitude when lightning strikes the line are used, and based on the steep wave head, short time interval and long duration, the lightning current parameters under lightning strike and lightning strike are obtained in combination with the direct lightning parameters.

[0012] Preferably, the equation for obtaining the lightning resistance level of the lightning tower when the lightning strikes the line is:

[0013]

[0014] Among them: k1 is the corona coefficient; k0 is the coupling coefficient between the lightning arrester and the conductor; β is the tower shunt coefficient; R ch is the tower grounding resistance; U 50％ is the 50% flashover voltage of the insulator string; L gt is the tower inductance; H d is the average height of the wire.

[0015] Preferably, the equations for obtaining the lightning strike distance to the ground wire, the lightning strike distance to the conductor, and the lightning strike distance to the earth are:

[0016] r s =10I 0.65

[0017] r c =1.63×(5.015I 0.578 +U ph ) 1.125

[0018]

[0019] Where: r sis the lightning strike distance to the ground wire; r c is the lightning strike distance to the conductor; r g h is the distance of lightning striking the earth; c.av is the average height of the conductor above the ground; U ph It is the instantaneous value of the power frequency phase voltage on the conductor.

[0020] Preferably, the acquisition of the lightning protection angle includes:

[0021] The lightning strike distance r to the ground line corresponding to different lightning current amplitudes I s and the lightning strike distance r c different;

[0022] When the lightning current amplitude I gradually increases, the exposed arc gradually shrinks; when the lightning current amplitude I increases to the critical current I m When , the exposure arc shrinks to zero;

[0023] When the lightning current amplitude I is greater than the critical current I m When , the lightning will directly hit the lightning conductor or hit the ground, and no lightning will be struck by a bypass. At this time, θ1 = θ2, and we have:

[0024]

[0025] Where: θ1 is the angle corresponding to the exposed arc at the lower end; θ2 is the angle corresponding to the exposed arc at the upper end; θ is the protection angle of the lightning conductor; H c is the height of the conductor above the ground; SC is the distance from the conductor to the lightning conductor.

[0026] Preferably, the critical striking distance is obtained by:

[0027]

[0028] Where: θ is the lightning protection angle; θ g is the ground inclination angle; h s h is the average height of the lightning conductor above the ground; c is the average height of the conductor above the ground.

[0029] Preferably, the equation for obtaining the lightning resistance level of the lightning-struck tower when the lightning strikes the line is:

[0030] I=4U 50％ / Z≈U 50％ / 100

[0031] Where: Z is the wave impedance of the transmission line.

[0032] Preferably, the step of obtaining lightning current parameters under lightning strike and shielding failure of the line includes:

[0033] Using the lightning strike amplitude when lightning strikes back on the line, and the lightning current amplitude when lightning shielding strikes the line obtained according to the lightning withstand level and critical current of the line when lightning shielding strikes the line, based on the steep wave head, short time interval and long duration, combined with the direct lightning parameter CIRGE, the parameters under 95% high probability in the lightning current waveform observation statistics, the most stringent lightning current parameters under lightning strike back and shielding strikes are obtained.

[0034] The embodiment of the present invention further provides a transmission line multiple lightning strike waveform parameter evaluation device, comprising:

[0035] The lightning strike module is used to obtain the lightning resistance level of the lightning tower when the lightning strikes the line; at the same time, it obtains the lightning amplitude when the lightning strikes the line;

[0036] The lightning shielding failure module obtains the critical current amplitude of the shielding failure under the lightning shielding failure mode according to the EGM strike distance theory; obtains the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, and the strike distance of lightning to the earth according to the critical current amplitude of the shielding failure; obtains the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, and the strike distance of lightning to the earth, and obtains the critical strike distance using the lightning protection angle;

[0037] According to the critical current amplitude of shielding failure, the lightning strike distance to the ground wire, the lightning strike distance to the conductor, the lightning strike distance to the earth and the critical strike distance, the critical current when the lightning shielding fails to pass the line is obtained; according to the critical current when the lightning shielding fails to pass the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning shielding fails to pass the line;

[0038] The lightning current amplitude module for shielding strikes the line. When the lightning withstand level is greater than the critical current, the lightning withstand level is classified as the lightning current amplitude. When the lightning withstand level is less than the critical current, the lightning withstand level and the critical current amplitude are simultaneously classified as the lightning current amplitude.

[0039] The lightning current parameter acquisition module uses the lightning stroke amplitude when the lightning strikes the line and the lightning current amplitude when the lightning strikes the line, and based on the steep wave head, short time interval and long duration, combines the direct lightning parameters to obtain the lightning current parameters under the lightning strike and the shielding line.

[0040] Preferably, the lightning shielding failure module includes a critical unit, a strike distance unit and a calculation unit;

[0041] The critical unit is used to obtain the critical current amplitude of the shielding failure under the lightning shielding failure mode according to the EGM strike distance theory;

[0042] The strike distance unit is used to obtain the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth according to the critical current amplitude of the shielding failure; obtain the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, and obtain the critical strike distance using the lightning protection angle;

[0043] The calculation unit is used to obtain the critical current when the lightning strikes the line according to the critical current amplitude of the shielding failure, the strike distance of the lightning to the ground wire, the strike distance of the lightning to the conductor, the strike distance of the lightning to the earth and the critical strike distance; according to the critical current when the lightning strikes the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning strikes the line;

[0044] When the shielding lightning current amplitude module judges the lightning withstand level and the magnitude of the critical current, the judgment result is the most severe lightning current amplitude when no flashover occurs and the most severe lightning current amplitude when flashover occurs;

[0045] When acquiring lightning current parameters, the lightning current parameter acquisition module selects parameters with a high probability of 95% as multiple lightning waveform parameters under extreme working conditions.

[0046] An embodiment of the present invention further provides an electronic device, including a memory and a processor;

[0047] The memory is used to store computer programs;

[0048] The processor is used to implement the steps of the above-mentioned method for evaluating multiple lightning strike waveform parameters of a power transmission line when executing the computer program stored in the memory.

[0049] The embodiment of the present invention provides a method, device and equipment for evaluating multiple lightning waveform parameters of a transmission line. Compared with the prior art, the beneficial effects thereof are as follows:

[0050] The present invention divides lightning strike modes into counter-strike and shielding strike, obtains the lightning resistance level and lightning strike amplitude when lightning directly strikes the line, and specifically analyzes the lightning strike distance to the ground wire, the lightning strike distance to the conductor, the lightning strike distance to the earth under lightning shielding strike, and the protection angle and critical strike distance when the lightning protection line is adopted, analyzes the critical current when lightning shielding strikes the line and the lightning resistance level of the lightning tower, and compares the critical current and the lightning resistance level when lightning shielding strikes the line to obtain the lightning current amplitude of the lightning shielding strikes the line under actual conditions of the line. Different from the method of directly using a lightning current sensor, the present invention divides lightning into direct counter-strike and shielding strike, and focuses on analyzing the lightning current amplitude when lightning shielding strikes the line, so that the analysis situation is closer to the actual situation of the line, and the captured lightning current is complete with low distortion, and then the lightning strike amplitude when the lightning strikes the line and the lightning current amplitude when the lightning shielding strikes the line are used to obtain the most stringent lightning current parameters, so that the evaluation accuracy of multiple lightning strike waveform parameters is greatly improved, and specific guidance can be provided for the design of ultra-ultra-high voltage AC transmission lines at this stage.

[0051] In addition, parameters such as tower grounding resistance, 50% flashover voltage of insulator string, tower inductance, coupling coefficient between lightning conductor and conductor, average conductor height, average height of lightning conductor to ground, distance from conductor to lightning conductor, lightning conductor protection angle, bottom inclination angle, etc. are all taken from actual transmission lines, which makes the design of transmission lines under actual conditions more targeted. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the overall process of a method, device and equipment for evaluating multiple lightning strike waveform parameters of a transmission line provided by an embodiment of the present invention;

[0053] Figure 2 A schematic diagram of an electrical geometric model of a lightning current shielding stroke line in a transmission line multiple lightning strike waveform parameter assessment method, device and equipment provided by an embodiment of the present invention;

[0054] Figure 3 A schematic diagram of a simulation waveform of bus overvoltage under the most severe counterattack multiple lightning strikes of a transmission line multiple lightning strike waveform parameter evaluation method, device and equipment provided by an embodiment of the present invention;

[0055] Figure 4 A schematic diagram of a simulation waveform of multiple lightning bus overvoltages under the most severe shielding failure when no flashover occurs, provided by a method, device and equipment for evaluating waveform parameters of multiple lightning strikes on a transmission line according to an embodiment of the present invention;

[0056] Figure 5 A schematic diagram of a simulation waveform of multiple lightning bus overvoltages under the most severe shielding stroke when a flashover occurs, provided by a method, device and equipment for evaluating waveform parameters of multiple lightning strikes on a transmission line according to an embodiment of the present invention;

[0057] Figure 6 A schematic diagram of the energy absorption process of the arrester under the most severe counterattack multiple lightning strikes of a transmission line multiple lightning strike waveform parameter evaluation method, device and equipment provided by an embodiment of the present invention;

[0058] Figure 7 A schematic diagram of the energy absorption process of the arrester under the most severe shielding failure multiple lightning strikes when no flashover occurs, provided by a method, device and equipment for evaluating waveform parameters of multiple lightning strikes on a transmission line according to an embodiment of the present invention;

[0059] Figure 8 A schematic diagram of the energy absorption process of a lightning arrester under the most severe shielding failure multiple lightning strikes when flashover occurs, provided by a method, device and equipment for evaluating waveform parameters of multiple lightning strikes on a transmission line according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0061] See also Figures 1 to 8 The embodiment of the present invention provides a method for evaluating multiple lightning waveform parameters of a transmission line, wherein the tower grounding resistance, the 50% flashover voltage of the insulator string, the tower inductance, the coupling coefficient between the lightning conductor and the conductor, the average height of the conductor, the average height of the lightning conductor to the ground, the distance from the conductor to the lightning conductor, the lightning conductor protection angle, and the bottom inclination angle are calculated; when calculating the lightning parameters, these parameters are all taken from the transmission line, there is no unified standard, and it depends on the specific situation.

[0062] The key points of lightning parameter calculation include:

[0063] ① When the system is equipped with lightning arresters, there are two situations where lightning strikes the line, which are more harmful to the system: one is that the lightning bypasses the lightning arrester and strikes the conductor, and the other is that the lightning strikes the top of the tower. By calculating the line's back strike lightning resistance level, shielding lightning resistance level, and shielding critical current, the amplitude of the intrusion lightning current in extreme cases can be obtained.

[0064] ② The remaining lightning parameters excluding the amplitude can be calculated by combining the statistical results of CIRGE observations on lightning current waveforms, and the parameters with a high probability of 95% can be preferably used for reduction.

[0065] The specific steps include:

[0066] Step 1: Calculate multiple lightning waveforms. First, calculate the maximum lightning current amplitude of the strike. After obtaining relevant parameters, calculate the lightning resistance level I1 of the lightning tower:

[0067]

[0068] Among them: k1 is the corona coefficient; k0 is the coupling coefficient between the lightning arrester and the conductor; β is the tower shunt coefficient; R ch is the tower grounding resistance; U 50％ is the 50% flashover voltage of the insulator string; L gt is the tower inductance; H d is the average height of the wire.

[0069] Step 2: Then, the critical current amplitude of the shielding failure is calculated by the strike and EGM strike distance theory, such as Figure 2 As shown; for a lightning current with an amplitude of I, the corresponding strike distance r can be obtained s 、r c and r g , the formula is as follows:

[0070] r s =10I 0.65

[0071] r c =1.63×(5.015I 0.578 +U ph ) 1.125

[0072]

[0073] Where: r s is the lightning strike distance to the ground wire; r c is the lightning strike distance to the conductor; r g h is the distance of lightning striking the earth; c.av is the average height of the conductor above the ground; U ph It is the instantaneous value of the power frequency phase voltage on the conductor.

[0074] Arc A i B i is the protective arc, arc BD is the exposed arc, plane DE is the ground lightning arresting surface, and the strike distance r corresponding to different lightning current amplitudes I s and r c Different; With the increase of lightning current amplitude, the exposed arc BD gradually decreases. When the lightning current amplitude increases to the critical current I m When the exposed arc BD shrinks to zero; the lightning current amplitude is greater than I m When the lightning strikes the lightning conductor or the ground, no more lightning strike occurs. At this time, θ1 = θ2, and the formula is as follows:

[0075]

[0076] Where: θ is the lightning protection angle; H c is the height of the conductor to the ground; SC is the distance from the conductor to the lightning conductor; then it can be known that the critical striking distance is r SC :

[0077]

[0078] Where: θ is the lightning protection angle; θ g is the ground inclination angle; h s h is the average height of the lightning conductor above the ground; c is the average height of the conductor above the ground.

[0079] The critical current when lightning strikes the line can be obtained through the above formula.

[0080] Step 3: Select the tower at the lightning strike location for verification and calculation, calculate the lightning protection level of the lightning strike point, and calculate the flashover lightning current amplitude as:

[0081] I=4U 50％ / Z≈U 50％ / 100

[0082] Where: Z is the wave impedance of the transmission line.

[0083] Step 4: In summary, the critical current and lightning resistance level under the shielding failure condition are obtained; if the critical current amplitude is greater than the shielding failure lightning resistance level, two severe lightning strike conditions of critical current and lightning resistance level are considered; if the critical current amplitude is less than the shielding failure lightning resistance level, only one lightning strike condition of lightning resistance level is considered.

[0084] Step 5: Parameters such as lightning strike interval and lightning strike waveform can be combined with the parameters under 95% high probability in the CIRGE observation statistics of lightning current waveform; the number of multiple lightning strikes is set to 5 times, and the statistical results of key waveform parameters are shown in Table 1. Taking steep wave head, short time interval and long duration as indicators, the most stringent lightning current parameters under the conditions of shielding and counter-strike are summarized.

[0085] Table 1 Direct current parameters calculated by CIRGE

[0086]

[0087] Specific applications:

[0088] Here, a 500kV ultra-high voltage AC transmission line is taken as an example to calculate the multiple lightning waveform parameters under extreme working conditions.

[0089] Under the counter-strike condition, the calculation formula of the system coupling coefficient k is k=k0k1, where k1 is the corona coefficient, which is 1.28; k0 is the coupling coefficient between the lightning arrester and the conductor, which is 0.22; the tower shunt coefficient is 0.88; the tower grounding resistance is 5.2Ω; the 50% flashover voltage of the insulator string is 2445.22kV; the tower inductance is 21.65μH; the average height of the conductor is 35.5m; based on the formula in step 1, the counter-strike lightning resistance level of the lightning fault point 218# tower B phase (right phase) is calculated to be 186.33kA.

[0090] Under the condition of shielding failure, the critical current of lightning is calculated first; the towers at both ends of the lightning strike point have a span of 242m, a lightning conductor height of 40.6m, a conductor height of 34.69m, a lightning conductor protection angle of 6.5°, and a slope inclination of 35°. Substituting r SC From the calculation formula of , we can get the critical striking distance as 111.6m; according to r s 、r c and r g According to the calculation formula, the critical current can be calculated to be 39.4kA; secondly, the lightning resistance level under shielding failure is calculated. During shielding failure, the voltage on the conductor increases with the increase of lightning current amplitude. If it exceeds 50%, the line insulation impulse flashover voltage is 2445.22kV, and the line insulation will flash over. According to the calculation formula of the flashover lightning current amplitude I, the theoretical analysis shows that the shielding lightning resistance level at this time is 24.45kA.

[0091] If the lightning current amplitude is the shielding lightning withstand level, the shielding line will not cause insulator flashover, and the energy of the lightning current will not be discharged to the ground through the tower, and almost all of it will be injected into the line arrester; if the lightning current amplitude is the critical lightning current, it will cause insulator flashover, and part of the energy will be discharged to the ground through the tower, but because the critical lightning current amplitude is greater than the shielding lightning withstand level, the energy contained in the lightning current itself is relatively large, and the shielding lightning withstand level at this time is less than the shielding critical current, it is impossible to determine which lightning situation has a greater impact on the arrester, therefore:

[0092] The shielding lightning withstand level is selected as the most stringent lightning current amplitude when no flashover occurs; the critical current is selected as the most stringent lightning current amplitude when flashover occurs.

[0093] Afterwards, based on the CIRGE statistical data mentioned in Table 1, the parameters under the 95% high probability are selected as the multiple lightning waveform parameters under extreme working conditions based on the maximum lightning current amplitude, the steepest wave head, the shortest lightning strike interval, and the longest duration. The corresponding lightning current parameters under counter-strike and shielding failure are obtained as shown in Tables 2, 3, and 4, and the overvoltage simulation results caused by lightning are shown in Tables 2, 3, and 4. Figures 3 to 5 The response of the arrester is as follows: Figures 6 to 8 shown.

[0094] Table 2 Multiple lightning strike parameters under the most severe strike back condition

[0095]

[0096]

[0097] Table 3 Multiple lightning strike parameters under the most severe shielding failure condition when no flashover occurs

[0098] Number of lightning strikes Occurrence time / ms Wave front time / μs Wave tail time / μs Lightning stroke amplitude / kA First Lightning Strike 0 1.8 200 24.45 Secondary lightning strike 7 0.22 140 24.45 Three lightning strikes 14 0.22 140 24.45 Four lightning strikes 21 0.22 140 24.45 Five lightning strikes 28 0.22 140 24.45

[0099] Table 4 Multiple lightning strike parameters under the most severe shielding failure condition when flashover occurs

[0100] Number of lightning strikes Occurrence time / ms Wave front time / μs Wave tail time / μs Lightning stroke amplitude / kA First Lightning Strike 0 1.8 200 39.4 Secondary lightning strike 7 0.22 140 39.4 Three lightning strikes 14 0.22 140 39.4 Four lightning strikes 21 0.22 140 39.4 Five lightning strikes 28 0.22 140 39.4

[0101] Compared with the previous method of directly bringing in multiple lightning stroke parameters under the standard for calculation, the multiple lightning waveform parameter evaluation method based on the calculation of lightning strike conditions integrates the actual line conditions and a large number of multiple lightning strike statistical results, and is more targeted; the evaluation method of the present invention can summarize the most severe lightning strike conditions of the line, and provide certain technical support for the safe operation of the system. When the line is not equipped with a monitoring device, the present evaluation method is more direct and effective; in response to the many recorded ultra-high voltage lightning arrester damage accidents that have occurred in recent years, the present evaluation method can meet the protection needs of multiple lightning strikes and provide guiding opinions for them; the present evaluation method integrates the actual line conditions and the statistical results of multiple lightning observations, and provides a reasonable boundary for the system's multiple lightning overvoltage analysis. Combined with the line parameters, it is suitable for the system insulation coordination design in the design stage.

[0102] The embodiment of the present invention further provides a transmission line multiple lightning strike waveform parameter evaluation device, comprising:

[0103] The lightning strike module is used to obtain the lightning resistance level of the lightning tower when the lightning strikes the line; at the same time, it obtains the lightning amplitude when the lightning strikes the line.

[0104] The lightning shielding failure module obtains the critical current amplitude of the lightning shielding failure mode according to the EGM strike distance theory; obtains the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth according to the critical current amplitude of the lightning shielding failure; obtains the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, and obtains the critical strike distance using the lightning protection angle.

[0105] According to the critical current amplitude of shielding failure, the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, the strike distance of lightning to the earth and the critical strike distance, the critical current when lightning shielding fails to pass the line is obtained; according to the critical current when lightning shielding fails to pass the line, the tower at the lightning strike location is verified and calculated to obtain the lightning resistance level of the tower when lightning shielding fails to pass the line.

[0106] The lightning current amplitude module for shielding strikes the line. When the lightning resistance level is greater than the critical current when the lightning strikes the line, the lightning resistance level is classified as the lightning current amplitude. When the lightning resistance level is less than the critical current, the lightning resistance level and the critical current amplitude are simultaneously classified as the lightning current amplitude.

[0107] The lightning current parameter acquisition module uses the lightning stroke amplitude when the lightning strikes the line and the lightning current amplitude when the lightning strikes the line, and based on the steep wave head, short time interval and long duration, combines the direct lightning parameters to obtain the lightning current parameters under the lightning strike and the shielding line.

[0108] Among them, the lightning protection module includes a critical unit, a strike distance unit and a calculation unit.

[0109] The critical unit is used to obtain the critical current amplitude of the lightning shielding failure mode according to the EGM strike distance theory.

[0110] The strike distance unit is used to obtain the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth according to the critical current amplitude of the shielding failure; obtain the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, and obtain the critical strike distance using the lightning protection angle.

[0111] The calculation unit is used to obtain the critical current when the lightning shielding strikes the line according to the critical current amplitude of the shielding strike, the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, the strike distance of lightning to the earth and the critical strike distance; according to the critical current when the lightning shielding strikes the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning struck tower when the lightning shielding strikes the line.

[0112] Among them, when the shielding lightning current amplitude module judges the lightning resistance level and the size of the critical current, its judgment result is the most severe lightning current amplitude when no flashover occurs and the most severe lightning current amplitude when flashover occurs.

[0113] When acquiring lightning current parameters, the lightning current parameter acquisition module selects parameters with a high probability of 95% as multiple lightning waveform parameters under extreme working conditions.

[0114] An embodiment of the present invention further provides an electronic device, including a memory and a processor.

[0115] The memory is used to store computer programs.

[0116] When the processor is used to execute the computer program stored in the memory, the steps of the above-mentioned method for evaluating the waveform parameters of multiple lightning strikes on a power transmission line are implemented.

[0117] In summary, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects; moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes; and the solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0118] The present invention is described with reference to the flowcharts or block diagrams of the methods, devices (systems), and computer program products of the embodiments of the present invention; it should be understood that each process or block in the flowchart or block, as well as the processes in the flowchart or block or the combination of the blocks, can be implemented by computer program instructions; these computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart or block. Figure 1 A process or multiple processes or boxes Figure 1 A device that specifies functions in one or more boxes.

[0119] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes or boxes Figure 1 A function specified in one or more boxes.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes or boxes Figure 1 A step that specifies a function in one or more boxes.

[0121] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for evaluating waveform parameters of multiple lightning strikes on a transmission line, characterized in that: The following steps are involved: Obtain the lightning resistance level and lightning amplitude of the lightning tower when the lightning strikes the line; According to the EGM strike distance theory, the critical current amplitude of the shielding strike when the lightning strikes the line is obtained; according to the critical current amplitude of the shielding strike, the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth are obtained; according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, the protection angle of the lightning conductor is obtained, and the critical strike distance is obtained using the protection angle of the lightning conductor; According to the critical current amplitude of shielding failure, the lightning strike distance to the ground wire, the lightning strike distance to the conductor, the lightning strike distance to the earth and the critical strike distance, the critical current when the lightning shielding fails to pass the line is obtained; according to the critical current when the lightning shielding fails to pass the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning shielding fails to pass the line; When the lightning withstand level when lightning strikes the line is greater than the critical current, the lightning withstand level is classified as the lightning current amplitude; when the lightning withstand level is less than the critical current, the lightning withstand level and the critical current amplitude are simultaneously classified as the lightning current amplitude; The lightning strike amplitude when lightning strikes the line and the lightning current amplitude when lightning strikes the line are used, and based on the steep wave head, short time interval and long duration, the lightning current parameters under lightning strike and lightning strike are obtained in combination with the direct lightning parameters.

2. A method for evaluating waveform parameters of multiple lightning strikes on a power transmission line according to claim 1, characterized in that: The equation for obtaining the lightning resistance level of the lightning tower when the lightning strikes the line is: Among them: k1 is the corona coefficient; k0 is the coupling coefficient between the lightning arrester and the conductor; β is the tower shunt coefficient; R ch is the tower grounding resistance; U 50％ is the 50% flashover voltage of the insulator string; L gt is the tower inductance; H d is the average height of the wire.

3. A method for evaluating waveform parameters of multiple lightning strikes on a power transmission line according to claim 1, characterized in that: The equations for obtaining the lightning strike distance to the ground wire, the lightning strike distance to the conductor, and the lightning strike distance to the earth are: r s ＝10I 0.65 r c =1.63×(5.015I 0.578 +U ph ) 1.125 Where: r s is the lightning strike distance to the ground wire; r c is the lightning strike distance to the conductor; r g h is the distance of lightning striking the earth; c.av is the average height of the conductor above the ground; U ph It is the instantaneous value of the power frequency phase voltage on the conductor.

4. A method for evaluating waveform parameters of multiple lightning strikes on a power transmission line according to claim 1, characterized in that: The acquisition of the lightning protection angle includes: The lightning strike distance r to the ground line corresponding to different lightning current amplitudes I s and the lightning strike distance r c different; When the lightning current amplitude I gradually increases, the exposed arc gradually shrinks; when the lightning current amplitude I increases to the critical current I m When , the exposure arc shrinks to zero; When the lightning current amplitude I is greater than the critical current I m When , the lightning will directly hit the lightning conductor or hit the ground, and no lightning will be struck by a bypass. At this time, θ1 = θ2, and we have: Where: θ1 is the angle corresponding to the exposed arc at the lower end; θ2 is the angle corresponding to the exposed arc at the upper end; θ is the protection angle of the lightning conductor; H c is the height of the conductor above the ground; SC is the distance from the conductor to the lightning conductor.

5. A method for evaluating waveform parameters of multiple lightning strikes on a power transmission line according to claim 1, characterized in that: The equation for obtaining the critical striking distance is: Where: θ is the lightning protection angle; θ g is the ground inclination angle; h s h is the average height of the lightning conductor above the ground; c is the average height of the conductor above the ground.

6. A method for evaluating waveform parameters of multiple lightning strikes on a power transmission line according to claim 1, characterized in that: The equation for obtaining the lightning resistance level of the lightning tower when the lightning strikes the line is: I=4U 50％ / Z≈U 50％ / 100 Where: Z is the wave impedance of the transmission line.

7. A method for evaluating multiple lightning waveform parameters of a power transmission line according to claim 1, characterized in that: The step of obtaining lightning current parameters under lightning strike back and shielding failure of the line includes: Using the lightning strike amplitude when lightning strikes back on the line, and the lightning current amplitude when lightning shielding strikes the line obtained according to the lightning withstand level and critical current of the line when lightning shielding strikes the line, based on the steep wave head, short time interval and long duration, combined with the direct lightning parameter CIRGE, the parameters under 95% high probability in the lightning current waveform observation statistics, the most stringent lightning current parameters under lightning strike back and shielding strikes are obtained.

8. A device for evaluating waveform parameters of multiple lightning strikes on power transmission lines, characterized in that: include: The lightning strike module is used to obtain the lightning resistance level and lightning amplitude of the lightning tower when the lightning strikes the line; The lightning shielding failure module obtains the critical current amplitude of the shielding failure under the lightning shielding failure mode according to the EGM strike distance theory; obtains the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, and the strike distance of lightning to the earth according to the critical current amplitude of the shielding failure; obtains the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor, and the strike distance of lightning to the earth, and obtains the critical strike distance using the lightning protection angle; According to the critical current amplitude of shielding failure, the lightning strike distance to the ground wire, the lightning strike distance to the conductor, the lightning strike distance to the earth and the critical strike distance, the critical current when the lightning shielding fails to pass the line is obtained; according to the critical current when the lightning shielding fails to pass the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning shielding fails to pass the line; The lightning current amplitude module for shielding strikes the line. When the lightning withstand level is greater than the critical current, the lightning withstand level is classified as the lightning current amplitude. When the lightning withstand level is less than the critical current, the lightning withstand level and the critical current amplitude are simultaneously classified as the lightning current amplitude. The lightning current parameter acquisition module uses the lightning stroke amplitude when the lightning strikes the line and the lightning current amplitude when the lightning strikes the line, and based on the steep wave head, short time interval and long duration, combines the direct lightning parameters to obtain the lightning current parameters under the lightning strike and the shielding line.

9. A transmission line multiple lightning waveform parameter assessment device according to claim 8, characterized in that: The lightning shielding failure module includes a critical unit, a strike distance unit and a calculation unit; The critical unit is used to obtain the critical current amplitude of the shielding failure under the lightning shielding failure mode according to the EGM strike distance theory; The strike distance unit is used to obtain the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth according to the critical current amplitude of the shielding failure; obtain the lightning protection angle according to the strike distance of lightning to the ground wire, the strike distance of lightning to the conductor and the strike distance of lightning to the earth, and obtain the critical strike distance using the lightning protection angle; The calculation unit is used to obtain the critical current when the lightning strikes the line according to the critical current amplitude of the shielding failure, the strike distance of the lightning to the ground wire, the strike distance of the lightning to the conductor, the strike distance of the lightning to the earth and the critical strike distance; according to the critical current when the lightning strikes the line, the tower at the lightning strike position is verified and calculated to obtain the lightning resistance level of the lightning tower when the lightning strikes the line; When the shielding lightning current amplitude module judges the lightning withstand level and the magnitude of the critical current, the judgment result is the most severe lightning current amplitude when no flashover occurs and the most severe lightning current amplitude when flashover occurs; When acquiring lightning current parameters, the lightning current parameter acquisition module selects parameters with a high probability of 95% as multiple lightning waveform parameters under extreme working conditions.

10. An electronic device, characterized in that: include: Memory and processor; The memory is used to store computer programs; The processor is used to implement the steps of a method for evaluating waveform parameters of multiple lightning strikes on a power transmission line as described in any one of claims 1 to 7 when executing the computer program stored in the memory.

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