| Electricity is the lifeblood of national economic development,and transmission lines are responsible for the transmission of electrical energy,due to the transmission lines cover a wide area,the pathway geographic environment is relatively complex,so that the transmission lines face great challenges to the safe and smooth transmission of electricity.According to statistical data,the main cause of transmission line tripping failure is caused by lightning strikes.Especially the ultra-high voltage transmission lines,because of its high voltage,tower structure size and transmission distance span characteristics,which makes transmission lines suffer from lightning strikes more frequently.The western part of Guangdong is a lightning-prone area affected by the subtropical monsoon climate,which poses a great threat to the safety of power grid operation in the region.In order to provide stable power to users,it is necessary to enhance the lightning protection performance of transmission lines.The environmental factors vary from region to region,so it is especially important to apply differentiated lightning protection technologies for transmission lines in different regions,taking into account factors such as topography,climate environment and lightning levels.This thesis takes the transmission lines in MM city in western Guangdong as the research object,analyzes the operation of transmission lines and lightning trips in recent years,and finds that 35 k V and 110 k V transmission lines suffer the highest probability of lightning trips.Therefore,35 k V transmission lines were mainly selected for analysis and research to determine the areas where lightning strikes occurred on transmission lines Louis,and the lightning damage causes were analyzed for the lightning protection measures of transmission lines in the area to find out the problems existing in the lightning strike protection work in MM area.Through the analysis of operational data from 2016-2019,the problems of lightning protection measures for 35 k V transmission lines in MM area are identified,and the use of combined lightning protection measures is proposed through the field climate environment,and various protection measures are modeled and verified through PSCAD software,and finally different combined lightning protection measures are adopted in a targeted manner.Through the two years of operation data in 2020 and 2021,it can be verified that the combined lightning protection measures can effectively improve the lightning resistance level of transmission lines.This thesis uses a combination of theoretical analysis and experimental research to conduct the study,with the following main work.(1)Analysis of the climate and geographical environment of MM city in western Guangdong,and its impact on lightning protection equipment.Through field sampling for corrosion hanging experiments to verify the impact of soil and atmospheric corrosion on lightning protection equipment,to demonstrate the need for differentiated lightning protection in the region.(2)Statistics on the operation of transmission lines and lightning trips in the MM area,and field surveys of the various environments through which transmission lines pass,and analysis of the high incidence areas of lightning strikes on transmission lines based on the survey results and historical lightning strike records and other information,laying the foundation for better subsequent lightning protection design.(3)analysis of MM area 35 k V transmission line #61 tower tripping the main reason,and through the PSCAD software modeling verification of various protection measures to determine the application of "copper-plated grounding system + inductive filtering lightning rod catcher" lightning protection measures in the 35 k V transmission line.After two years of operation,the number of lightning strikes on 35 k V transmission lines is significantly reduced,confirming that the combination of lightning protection measures for transmission lines have an effect on lightning protection. |
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