Application Research On Lightning Protection Of Transmission Lines In Dali Power Grid

With the development of the new type of power system,the insulation level in the power grid is constantly enhanced,and the lightning resistance level of the line is rapidly improved.while the lightning harm to retreat to a secondary position,operating overvoltage occupies the dominant position in the insulation coordination.However,the insulation tolerance of cables in power network is closely related to the working voltage and overvoltage of high voltage transmission lines,and it is improved continuously on the basis of certain interactive influence.In 2018,more than 30 lightning strikes occurred in 35 k V and above lines under the jurisdiction of Dali power supply bureau,including 2 times of 500 k V,15 times of 110 k V and 9times of 35 k V.In the field of power management,in order to effectively reduce the incidence of lightning strike trip and improve the reliability of power supply,it is necessary to carry out lightning protection treatment,which also has important research significance.According to data statistics from 2013 to 2019,the main reason for the trip of transmission lines in Dali power grid is lightning strike,and the trip times caused by lightning strike are the most.After the transmission line is struck by lightning,the wire and ground wire are easily damaged and cause trip.In serious cases,it will also lead to the invasion of lightning wave,which will damage the substation and cause safety accidents.For long distance power grid,the regional meteorological complex terrain of the corresponding accident of lightning discharge is more serious,after the lightning fault point number,large range,it is difficult to accurately and efficiently repair,this is very bad influence to the power supply.Therefore,it is necessary to clarify the causes of lightning damage in transmission lines of Dali power grid on the basis of detailed investigation,specifically analyze the lack of existing lightning protection measures,and make some optimization and improvement to provide support for the reliable and stable operation of the power grid,which also has high research value and practical significance.This paper takes the actual grid frame of Dali power grid as an example,establishes a simulation model,and further analyzes the actual problems existing in the lightning protection technology of Dali power grid with the support of a large number of actual operation data and combining the simulation with the reality,and gives the specific measures for the lightning protection of Dali power grid.