Distribution arrester damage model correction method based on random lightning impulse

Abstract

The invention discloses a power distribution lightning arrester damage model correction method based on random lightning impulse, and relates to the lightning arrester damage effect model research field, and the method comprises the following steps: S1, carrying out an impulse current amplitude influence test, adjusting an impulse current amplitude, and carrying out the research of the damage effect of a lightning arrester valve plate on lightning impulse currents with different amplitudes; s2, an impact current waveform influence test is carried out, the impact current waveform is adjusted, and the destructive effect of the lightning arrester valve plate on the lightning impact current with different waveforms is researched; s3, impulse current pulse interval influence test: adjusting impulse current pulse intervals, and researching destructive effects of the lightning arrester valve plate on lightning impulse currents with different pulse intervals; and S4, multiple combined pulse influence experiments are carried out, pulse intervals and pulse amplitudes are randomly generated, and the destructive effect of the lightning arrester valve plate on the lightning impulse current of the random rich pulses is researched.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of research on the destructive effect model of lightning arresters, and particularly relates to a distribution lightning arrester destructive model correction method based on random lightning impulse. BACKGROUND

[0002] In a distribution line, a zinc oxide lightning arrester is a key device for protecting electrical equipment from lightning overvoltage, especially induced lightning overvoltage, and for protecting electrical equipment. The reliability of the valve piece of the zinc oxide lightning arrester is directly related to the safe and stable operation of the entire system. Natural lightning has the characteristics of randomness and instantaneity, which brings difficulties to lightning protection related work, especially the establishment of the destructive effect model of lightning arresters. The simulation of lightning events and the optimization of lightning protection measures have great significance.

[0003] At present, the research on the destructive effect of lightning arrester valve pieces is mostly based on standard lightning impulse waveforms (such as 4 / 10 μs, 8 / 20 μs, etc.) and fixed impulse numbers. The test conditions are often idealized, and the amplitude, waveform, pulse interval and sequence combination of natural lightning are not fully considered. Although the resistance of the valve piece can be tested to a certain extent, the deterioration process of the valve piece under the action of random multi-pulse lightning is difficult to truly reflect, and the destructive effect model established based on the traditional test may have significant deviations in actual engineering applications. The present application develops a distribution lightning arrester destructive model correction method based on random lightning impulse to more truly reflect the performance of lightning arrester under actual operating conditions, and provides a more accurate evaluation method for the reliability and safe operation of power systems. SUMMARY

[0004] The purpose of the present application is to provide a distribution lightning arrester destructive model correction method based on random lightning impulse to solve the problem that the destructive effect model of lightning arresters in the prior art is mostly based on standard lightning impulse waveforms and fixed impulse numbers, and does not fully consider the randomness and diversity of the amplitude, waveform, pulse interval and sequence combination of natural lightning, which is difficult to truly reflect the deterioration process of the valve piece under the action of random multi-pulse lightning, resulting in significant deviations of the model in actual engineering applications.

[0005] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme: a distribution lightning arrester destructive model correction method based on random lightning impulse, comprising the following steps:

[0006] S1, an impulse current amplitude influence test is performed, the impulse current amplitude is adjusted, and the destructive effect of lightning impulse current of different amplitudes on the lightning arrester valve piece is researched;

[0007] S2, impact current waveform influence test, adjust the impact current waveform, study the destructive effect of lightning impulse current with different waveforms on the valve piece of the lightning arrester;

[0008] S3, impact current pulse interval influence test, adjust the impact current pulse interval, study the destructive effect of lightning impulse current with different pulse intervals on the valve piece of the lightning arrester;

[0009] S4, multiple combination pulse influence test, the pulse interval and the amplitude of each pulse are randomly generated, and the destructive effect of lightning impulse current with random rich pulses on the valve piece of the lightning arrester is studied;

[0010] S5, definition of characteristic parameters of destructive effect of lightning arrester, obtain the change of output parameters of destructive effect of lightning arrester valve piece with impact current amplitude, impact current amplitude, impact current pulse interval and rich pulse current;

[0011] S6, according to the output parameter, the characteristic relationship curve between the damage probability of the lightning arrester valve piece and the cumulative absorption energy is fitted, and the energy absorption damage probability model of the lightning arrester is corrected.

[0012] Further, the impact current with different amplitudes involves 5-kA amplitude range impact high current discharge; the impact current with different waveforms is 4 / 10 mu s, 8 / 20 mu s, 90 / 200 mu s and other standard impact current waveforms debugged by the impact current discharge system; the different current pulse intervals are set to 10ms-500ms between each pulse of the multi-pulse current; the combination pulse randomly generates the pulse time interval and the amplitude of each pulse of the multi-pulse current through PLC control.

[0013] Further, the characteristic parameters of the lightning arrester damage effect are defined as follows:

[0014] Limit absorption energy: the critical absorption energy EJ before breakdown of the lightning arrester;

[0015] 50% damage energy: when the impact energy is applied to the lightning arrester sample, the energy E50% corresponding to the damage of about 50% samples;

[0016] Energy damage probability: based on the test data of all valve pieces, taking the absorption energy as the horizontal coordinate and the damage probability as the vertical coordinate, the energy-damage probability relationship curve of the lightning arrester is obtained through statistical fitting.

[0017] Compared with the prior art, the lightning arrester damage model correction method based on random lightning impulse provided by the application can simulate the multi-pulse and randomness characteristics of actual lightning current through multiple capacitors.

[0018] The test comprehensively tests the change of the destructive effect of the lightning arrester under the influence of the lightning current amplitude, the lightning current waveform, the lightning current pulse interval and various combined pulses.

[0019] Through systematic experiments and modeling, the destruction threshold and failure mechanism of the valve piece under the action of random lightning current multi-influence factors are determined, which can provide a theoretical basis for the construction of lightning arrester model, line lightning transient research and power system overvoltage protection design. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0021] Figure 1 The lightning random parameter injection under the lightning arrester destructive test flowchart provided by the embodiment of the present application is provided.

[0022] Figure 2 The random multi-pulse lightning current schematic diagram provided by the embodiment of the present application is provided.

[0023] Figure 3 The lightning arrester withstand lightning energy change curve influenced by the current amplitude provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0024] In order to make those skilled in the art better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings.

[0025] As shown in the accompanying Figure 1 to the accompanying Figure 3 , the present application provides a distribution lightning arrester destruction model correction method based on random lightning impulse, and a lightning arrester destructive effect test flowchart.

[0026] The test flowchart is shown in

[0027] The present application provides a distribution lightning arrester destruction model correction method based on random lightning impulse, and a lightning arrester destructive effect test flowchart.

[0028] The test flowchart is shown in Figure 1The random setting of lightning parameters was simulated, and a specific waveform of the impulse current could be generated using an impulse voltage generator. The amplitude of the impulse current was controlled by adjusting the set charging amplitude of the impulse voltage generator to conduct amplitude influence experiments. The resistance, inductance, and capacitance components of the impulse voltage generator were manually adjusted to achieve current influence characteristic tests of different waveforms. The pulse interval was controlled by adjusting the ignition time of the multi-pulse capacitor to conduct pulse interval influence experiments. For multiple combined pulse influence experiments, the multi-pulse lightning current generation device was controlled by a PLC (Programmable Logic Controller) to randomly generate the amplitude and interval of each pulse. Each test condition was repeated at least 10 times, repeatedly impacting until the arrester valve was damaged. The current and voltage of each valve were recorded. The ultimate energy absorbed by each valve was calculated from the recorded current and voltage waveforms. Furthermore, by statistically analyzing the energy absorbed by the arrester and the probability of failure under each condition, a fitting curve of the energy absorbed by the valve and the probability of failure was obtained, further refining the arrester damage effect model.

[0029] Detailed instructions for pulse current settings:

[0030] Figure 2 The schematic diagram of the multi-pulse lightning current shown illustrates how a lightning current with an amplitude I of 5–100 kA is modulated using an impulse voltage generator amplitude adjustment device to simulate different degrees of lightning strikes. Standard impulse current waveforms such as 4 / 10 μs, 8 / 20 μs, and 90 / 200 μs are generated by adjusting the relevant electrical components of the surge arrester. Different pulse intervals, ranging from 10 ms to 500 ms, are simulated by adjusting the pulse intervals ΔT1, ΔT2, ..., ΔTn+1 through the ball gap trigger control system of the multi-pulse lightning current generation device. The PLC (Programmable Logic Controller) controls the multi-pulse lightning current generation device to randomly generate the amplitude and interval of each pulse, simulating the randomness of real lightning strikes.

[0031] Detailed explanation of the output parameters of the destructive effect:

[0032] The energy absorbed by the surge arrester is obtained by integrating the current and voltage parameters of the valve plate under each impulse, and the calculation formula is as follows: Where t1 and t2 are the triggering and termination times of the lightning current on the surge arrester valve, u is the voltage across the surge arrester valve, and i is the surge arrester current. For the same type of valve, 10 valves are selected for repeated experiments. If 5 valves fail at a certain energy level, then that energy is 50% of the failure energy of that type of valve. Figure 3 The curves showing the effect of the surge arrester's lightning withstand energy on the amplitude of an 8 / 20μs waveform single-pulse current are presented. The withstand energy is based on only one test result, and each type of valve is subjected to a maximum of 18 tests. If the valve does not break down, the energy absorbed by 18 impacts is used for calculation.

[0033] Detailed explanation of the fitting curve and model correction for the destructive effect of surge arresters:

[0034] To assess the impact of each of the above-mentioned influencing factors, at least 10 surge arrester valves of the same model were selected for repeatable testing in each group of experiments. Based on the measured voltage and current data of the surge arrester valves, the ultimate withstand energy of the valves was determined. The probability of valve damage at each energy level was statistically analyzed, and finally, the fitting curve of surge arrester valve damage probability - absorbed energy was obtained through numerical analysis to correct the destructive effect model of the surge arrester.

[0035] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for correcting the failure model of distribution surge arresters based on random lightning impulses, characterized in that, Includes the following steps: S1. Impact of impulse current amplitude test: Adjust the impulse current amplitude to study the destructive effect of the surge arrester varistor on lightning impulse currents of different amplitudes; S2. Impact test of impulse current waveform: Adjust the impulse current waveform to study the destructive effect of the surge arrester varistor on lightning impulse currents of different waveforms. S3. Impact Test of Impulse Current Pulse Interval: Adjust the impulse current pulse interval to study the destructive effect of the arrester varistor on lightning impulse current with different pulse intervals. S4. Experiment on the effects of multiple combined pulses: The pulse interval and amplitude of each pulse are randomly generated to study the destructive effect of the surge arrester varistor on the random and abundant pulses of lightning impulse current. S5. The characteristic parameters of the destructive effect of the surge arrester are defined, and the output parameters of the destructive effect of the surge arrester varistor are obtained as a function of the impulse current amplitude, impulse current amplitude, impulse current pulse interval, and rich pulse current. S6. Fit the characteristic relationship curve between the arrester valve failure probability and the cumulative absorbed energy based on the output parameters, and correct the arrester energy absorption damage probability model accordingly.

2. The method for correcting the failure model of distribution arresters based on random lightning impulses according to claim 1, characterized in that, The different amplitude impact currents involve impact large current discharges in the 5-kA amplitude range; the different waveform impact currents are standard impact current waveforms such as 4 / 10μs, 8 / 20μs, and 90 / 200μs, which are debugged by the impact current discharge system; the different current pulse intervals are the interval time between each pulse of the multi-pulse current set to 10ms to 500ms; the combined pulses are randomly generated by PLC control of the pulse time interval and the amplitude of each pulse of the multi-pulse current.

3. The method for correcting the failure model of distribution arresters based on random lightning impulses according to claim 1, characterized in that, The characteristic parameters of the surge arrester damage effect are defined as follows: Ultimate energy absorption: The critical energy EJ absorbed by the surge arrester before breakdown; 50% damage energy: When an impact energy is applied to the surge arrester samples, the energy corresponding to the damage of approximately 50% of the samples is E50%. Energy failure probability: Based on the test data of all valve plates, the energy absorption is used as the abscissa and the failure probability is used as the ordinate. The energy-failure probability relationship curve of the surge arrester is obtained by statistical fitting.

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