Chongqing Lightning Protection Center

Chongqing, China

Chongqing Lightning Protection Center

Chongqing, China

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Yang L.,Chongqing Lightning Protection Center | Qin B.-Q.,Chongqing Lightning Protection Center | Luo F.,Chongqing Lightning Protection Center | Mi X.,Chongqing Lightning Protection Center
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

This paper briefly introduces the principles of linear 3-pole wiring method to form current circuit through soil to measure grounding resistance; discusses the feasibility of linear 3-pole wiring method to measure the grounding resistance of buildings (structures) in water; adopts comparative method to carry out field measurement on the grounding resistance of representative grounding devices in water and the grounding resistance of grounding devices in the soil adjacent to water; discusses the applicability and validity of linear 3-pole wiring method to measure the grounding resistance of buildings (structure) in water through variance analysis and correlation coefficient analysis methods, and solves the problem about how to measure the grounding resistance of buildings (structures) in water. © 2014 IEEE.


Mi X.,Chongqing Lightning Protection Center | Qin B.-Q.,Chongqing Lightning Protection Center | Yang L.,Chongqing Lightning Protection Center | Liu Q.-S.,Chongqing Lightning Protection Center
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

Because of the huge structure and special position, bridge is vulnerable to lightning stroke. As the most important bearing member of cable supported bridge, once the cable suffering the lightning stroke, the structural safety of the bridge will be affected. The bridge cable used actually was sampled and carried out lightning stroke simulation experiment in laboratory, the influence of lightning stoke on bridge cable was analyzed through five experimental models, the truth that lightning stroke can cause high-tensile steel wire melting loss was discovered. The tensile strength change of high-tensile steel wires before and after the lightning stroke was analyzed through tensile test, the result shows that tensile strength of high-tensile steel wires is reduced significantly. The breakdown strength of high density polyethylene sheath was calculated through impulse voltage breakdown test, the result shows that the high density polyethylene sheath can not endure the lightning stroke in nature. Experimental analysis indicates that the lightning protection of the bridge cable must be strengthened. © 2014 IEEE.


Li J.,Chongqing Lightning Disaster Identification and Protection Project Engineering Research Center | Li J.,Chongqing Lightning Protection Center | Luan J.,Liaoning Lightning Protection Technical Service Center | Wang P.,Liaoning Lightning Protection Technical Service Center | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2014

To analyze and use the data of lightning location system (LLS), it is necessary to perform quality control of the data, for example, excluding some small amplitude cloud-to-cloud lightning which is inevitably mistaken to cloud-to-ground lightning (CG) by LLS. Using the lognormal distribution function, we performed fitting and analysis of the data obtained by a lightning location system in Chongqing, China from 1999 to 2008. It is found that by ignoring the data of lightning with amplitudes less than 5 kA (which occupies 1.05% of the total data), we obtained the best fitting result that passes the test of statistical significance and reflects the statistical characteristic of CG. We also analyzed the variation of frequency distribution and proportion of different region of small amplitude CG, and found that ignoring the CG data blow 5 kA not only accords with the error feature of LLS, but also reflects the effect of upgrading LLS devices in decreasing deviation. Therefore, we delimit the "small amplitude" of lightning in Chongqing as below 5 kA. The result could be referred by researches of "small amplitude" lightning and quality control LLS data for other geographic regions.


Chen L.,Chongqing University | Li Y.-F.,Chongqing University | Sima W.-X.,Chongqing University | Yang Q.,Chongqing University | And 2 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2011

Analysis of temporal law of lightning is fundamental for lightning protection design, reforming and early warning of transmission line. We investigated the time-clustering characteristic of lightning data recorded by lightning detection system by means of Cv and Allan factor methods. Moreover, we used lightning data monitored in a city of China, from the year 2008-2009, to demonstrate the phenomenon of clustering of lightning, furthermore, we investigated the time scale of such clustering by Allan factor. The results reveal that the fractal onset time of lightning data is about 300 s, and from 300 s to 106.5 s, Allan factor on the log-log figure displays two time-scaling regions-two regions with different fractal exponents. Fractal exponents of the first region are 1.6373(in 2008) and 1.6461(in 2009), while those of the second region are 0.5297(in 2008) and 0.3724(in 2009), respectively. Finally, the physical meaning of crossover between two regions is explained.


Li Y.-F.,Chongqing University | Sima W.-X.,Chongqing University | Chen L.,Chongqing University | Yang M.,Chongqing University | Qin B.-Q.,Chongqing Lightning Protection Center
Gaodianya Jishu/High Voltage Engineering | Year: 2011

We adopted global digital elevation data to complete the elevation information of lightning detection data in some region of China, from 2007 to 2010. Furthermore, we also adopted 3D lightning detection data to investigate the law of lightning current amplitude, ground flash density(GFD) and proportion of positive flash with the change of elevation. The results are as follows: the height of thunderstorm base above ground decreases with the increasing of elevation, and upgoing lightning current amplitude is generally low in mountains, so the lightning current amplitudes of both positive flash and negative flash increase with the increasing of elevation. Relationship between elevation and logarithm of mean of lightning current amplitude is expressed by fitting lines. Ground flash density of negative flash decreases sharply with the increasing of elevation, which makes GFD of negative flash in high altitude region to be the only 1/3 of GFD of negative flash in low altitude region. On the contrary, GFD of positive flash increases with the increasing of elevation. With the increasing of elevation, the proportion of positive flashes increases by 300%. Besides, water area obviously affects the lightning current, which may be the reason of the diversity of lightning current statistic results from high altitude and low altitude regions.


Du L.,Chongqing University | Yu S.,Chongqing University | Mi X.,Chongqing Lightning Protection Center | Yang Q.,Chongqing University | Wang Y.,Chongqing University
Przeglad Elektrotechniczny | Year: 2012

To analyze exactly the wave propagation processes of a transmission tower when lightning strikes, an equivalent model of a transmission tower was studied in this paper. First, based on the correlative theory of tapered antenna, an equivalent surge impedance model of a single stanchion of tower was made. This tower was regarded as a four-conductor system according to the real configuration of a tower, and the equivalent impedance of the four-conductor system was obtained by multiplying the single pillar impedance with the compensation factor. Combined with the definition of wave impedance regarded with inductance and capacitance, the compensation factor of the four-conductor system was introduced. Then, the bracings equivalent model was obtained based on the analysis of the effect of bracings on the main body of a tower, and an equivalent impedance model of the crossarms was built base on the correlation theory of the equivalent model of parallel multi-conductors. In modularizing the tower model, the equivalent impedance of the tower was found. Finally, a 500 kV tower was calculated in this paper using the equivalent impedance model of the tower.


Binquan Q.,Chongqing Lightning Protection Center | Mi X.,Chongqing Lightning Protection Center | Yan R.,Chongqing Lightning Protection Center | Liangfu L.,Chongqing Meteorological Bureau
2011 7th Asia-Pacific International Conference on Lightning, APL2011 | Year: 2011

In allusion to the security of people in a straddle-type monorail vehicle when the straddle-type monorail vehicle is struck by lightning, this article carries out calculation and analysis of two cases, i.e. people in the vehicle are not in contact with the metallic components which directly connecting the metallic housing of the vehicle, and people are in contact with the metallic components which directly connecting the metallic housing of the vehicle and concludes that in the former case, people are completely safe; and in the latter case, people will feel tingle or causalgia, but do not threaten the safe of life. © 2011 IEEE.


Yu S.,Chongqing Lightning Protection Center | Ren Y.,Chongqing Lightning Protection Center
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

Reasonable and scientific lightning disaster risk assessment can effectively reduce losses caused by lightning, but at present the lightning risk assessment system is not perfect, sometimes it cannot well evaluate actual lightning disaster risks. For some certain occasions, IEC62305-2 standard dose not well reflect the true lightning risk, such as large-scale residential district, a large area factory, etc. In these cases, On the basis of in-depth study on the mechanism of lightning disaster, we can analyze the lightning risk by three aspects of hazard, exposure and vulnerability of hazard bearing body. Then we select eleven lightning risk factors such as ground flash density, lightning current intensity, lightning current steepness, the number of personnel, the equivalent property, relative height, floor space, nature of use, effective spacing, etc. At last by AHP and fuzzy mathematics theory, we obtain the lightning risk assessment formula for Chongqing region. Through the lightning risk assessment method Specific assessment verification shows that this method has better applicability and can better serve lightning protection and disaster reduction in Chongqing region, it can be a good supplement for IEC62305-2 lightning risk assessment. © 2014 IEEE.


Sima W.,Chongqing University | Li Y.,Chongqing University | Yang Q.,Chongqing University | Yuan T.,Chongqing University | Qin B.,Chongqing Lightning Protection Center
Gaodianya Jishu/High Voltage Engineering | Year: 2012

To deal with disadvantages that the credibility and spatial resolution of lightning parameters calculated by traditional grid method (TGM) are not high enough, we proposed an improved grid method (IGM). IGM substitutes a couple of parameters (grid area and monitored radius) for the single parameter (grid area) in TGM. Taking lightning data recorded by lightning location system in Chongqing as an example, we illustrate the differences of the two methods in the statistics of thunderstorm day, thunderstorm hour and ground flash density. The results show that the three kinds of lightning parameters don't change sharply with the improvement of spatial resolution by the method of IGM, and the physics meanings of lightning parameters gained by means of IGM are clearer than the ones by means of TGM. Therefore, compared with the TGM, the spatial resolution and credibility of lightning parameters calculated by IGM is better, which can provide a good support for the differentiated lightning protection design.


Du L.,Chongqing University | Mi X.,Chongqing University | Mi X.,Chongqing Lightning Protection Center | Xiao Z.,Chongqing University | And 4 more authors.
Gaodianya Jishu/High Voltage Engineering | Year: 2012

In order to analyze the wave processes in the transmission tower struck by lightning, we studied equivalent models of cross arm and inclined holder based on an existing equivalent transmission tower model. The theory of parallel multi-conductor was applied to study the equivalent tower cross arm model. The equivalent inclined holder model was derived by multiply a compensation factor of inclined holder on the equivalent impedance model of tower main body. Meanwhile, the compensation factor of inclined holder was constituted by the capacitance and inductance compensation factor which were obtained by calculating the variation of electric field energy and magnetic field energy caused by inclined holder. The values of the capacitance and inductance compensation factor were 0.9895 and 0.8360, respectively, and the compensation factor of inclined holder turned out to be 0.8272. Moreover, according to the calculation method of the equivalent impedance models of cross arm and inclined holder, the equivalent impedance model of a 500 kV SZC3 tower was established to analyze its surge process under lightning stroke.

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