Research On Simulation Calculation Of Lightning Withstand Performance Of UHV Transmission Lines

In recent years,the UHVDC transmission line project is the key project to promote the development of the power system.Because of its long line,long cross region,remote stringing point and other characteristics,it is easy to be affected by lightning in the actual operation process.Therefore,further reducing the impact of lightning on the UHVDC transmission line will be conducive to the healthy and stable development of the power grid.Therefore,this thesis takes UHV transmission line as the research object,focuses on its lightning withstand performance,and deeply analyzes various influencing factors.Firstly,the impulse flashover voltage of transmission line insulator is simulated,and the lightning withstand performance of transmission line is deeply analyzed.The main research work of this thesis is as follows(1)COMSOL software is used to simulate the insulator.This thesis takes 110kV insulator as an example to carry out simulation calculation research,and carries out simulation research on the impulse flashover voltage under working voltage and lightning impulse voltage respectively,so as to obtain the simulation calculation results.At the same time,it carries out comparative research with the experimental values of other thesis,and further illustrates the feasibility of using simulation method to obtain the impulse flashover voltage of insulator sex.Based on this,the simulation calculation of ±800kV insulator is carried out,and the differences between simulation results and experimental values are compared and analyzed.(2)Based on PSCAD,the simulation model of counterattack and lightning withstand for UHV transmission line is built.In this thesis,PSCAD is used to model and analyze the UHVDC transmission line,and the structure model of counterattack and lightning withstand based on PSCAD is constructed.Based on the regulation method,the Flashover Rate Index of counterattack is simulated and calculated.In addition,the other factors affecting the lightning withstand performance of UHV transmission lines are studied,including surface hydrophobicity,pollution accumulation and insulator type.(3)Propose a lightning protection performance model based on improved electrical geometry model to construct a shielding lightning resistance of transmission lines.This thesis studies the improvement of the electrical geometry model,and presents an improved shielding lightning performance model.The factors such as working voltage,wind speed and protection angle are considered in the modeling and analysis.Finally,all kinds of factors that affect the shielding failure performance model of UHV transmission line are analyzed one by one...