Research On Lightning Protection Risk Assessment And Reconstruction Design Of 220kV Transmission Lines In Liangshan Power Supply Company

Electric power industry,which is fundamental and supportive to China’s industrial production and people’s life,has made great progress in recent years.Such great projects as West-to-East Power Transmission Project and Rural Power Grid Upgrading,etc.,have been carried out vigorously,leading to the appearance of a large number of HV,EHV and UHV transmission lines,with complex crossing terrains and more frequent transmission line trip accidents incurred by lightning disasters.For the purpose of enhancing the lightning protection status of transmission lines,this paper takes the lightning trip status of Changshan Line I in Liangshan Prefecture as the research object,evaluates and transforms the lightning protection status of 220 k V overhead transmission lines.Focusing on the lightning protection evaluation and reconstruction design of Changshan Line I,this paper primarily makes the following research:(1)The lightning formation principle and process are studied,the lightning voltage,lightning current and lightning overvoltage are discussed thoroughly,the concepts of thunderstorm day,thunderstorm hour,ground flash density and lightning current amplitude are expounded,and the analysis and calculation methods of lightning shield and lightning strike are analyzed and compared in detail;(2)The current status of 220 k V transmission line in Liangshan Prefecture is analyzed.The lightning characteristic parameters and line characteristic parameters of Changshan Line I are counted.The shielding failure trip-out rate of Changshan Line I 1 is calculated based on the electrical geometry model.The counterattack trip rate of Changshan Line I 1 is calculated by Monte Carlo method.According to the actual situation,the lightning flashover risk assessment standard is established,and the risk of shielding flashover and counterattack flashover are evaluated;(3)According to the lightning parameters,lightning protection measures and previous operation experience of the line,the principle and scheme of lightning protection upgrading for Changshan Line I are determined,and the advantages and disadvantages of various lightning protection measures are analyzed.The lightning protection measures of installing line arrester and controllable discharge lightning rod,and reducing grounding resistance are determined.In the end,the lightning protection upgrading scheme is formulated and evaluated.The results show that the lightning protection upgrading scheme of the current design is effective,and able to reduce the lightning trip-out rate of Changshan Line I,enhance the safe and stable operation ability of Changshan Line I,and ensure the normal production and life of local enterprises and residents.