Dissertation > Industrial Technology > Building Science > Housing construction equipment > Mechanical and Electrical Equipment > Power control,relay protection and grounding lightning protection

Applied Research on Permafrost Resistivity in Lightning Protection Engineering

Author LiuYanChao
Tutor JiangYongQing
School Harbin University of Science and Technology
Course Safety Technology and Engineering
Keywords permafrost lighting protection engineering permafrost resistivity permafrost temperature and permafrost moisture
Type Master's thesis
Year 2013
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Civilian buildings of expected number of lightning strikes reaches greaterthan or equal to0.06times/a and less than or equal to0.3times/a,and generalindustrial buildings of greater than or equal to0.06times/a need to take accidentmeasures of prevention of lightning in National Institute of Standards of Designcode for protection of structures against lightning. Electric current sounding ismostly taken to test power frequency grounding resistance of lightning protectionfacilities.The ground is extremely difficult to detect of traditional method and levelJump of soil resistivity has been occured due to the presence of permafrost in thenortheast of China in winter. Furthermore,the lightning monitoring could not betimely and excessive deviation of ground resistance test data and the actual dataof the thunderstorm season,and the safety incidents occurs frequently. In thispaper, the resistivity value of the permafrost region is too large to reflect the trueearth resistance value accurately in the lightning protection engineering. Thepaper mainly on these following works:1.The influencing factors and methods of measurement of soil resistivity areanalyzed and compared,and This study provide a theoretical basis for theestablishment of the permafrost experimental model and determine theexperimental measurement solutions.2.To establish the regression model of permafrost temperature,permafrostmoisture and permafrost resistivity by measuring the corresponding date underthe different depth,and analyzing the corresponding and Characters of permafrostresistivity.3.To establish and determine the optimum regression model of permafrosttempersture and permafrost moisture under the different depth of5cm,15cm and25cm,and analyze and get the model the importance degree of each predictor variables.4.Analyzing and establishing optimal prediction model of the resistivitybetween the permafrost and non-permafrost resistivity by analysis the fittingmodel of the permafrost and non-permafrost resistivity,and determine estimationformula between the permafrost and non-permafrost resistivity on this basis.5.The application of CFD software Ansys and Fluent with the experiment inthe process of melting permafrost on soil temperature and soil moisture werenumerically simulated, and the results between numerical simulation andexperimental measurement were compared and analyzed.This article mainly obtained and verified the formula of the permafrostresistivity and the relationship between the structure of permafrost and non-permafrost by analyzing the factor of soil resistivity,and providing a basis for thecorrect design of grounding device in lighting protection engineering.

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