反击计算模型和方法

AbstractLightning disaster seriously affects people's normal life,from the damage offacilities to the occurrence of large-scale blackout accidents,so the prevention oflightning disaster is still the key to the safe and stable operation of the power system.According to statistics,lightning accident will not only cause single-phase flashoverof transmission line tower,but also cause serious tripping accident of two circuits atthe same time.According to the special topography,complex line structure and other factors inShiyan mountain area,lightning accidents occur frequently,and the stability of localpower system is seriously threatened.In the past five years,lightning flashoveraccidents occurred many times on 220kV transmission lines in this area.Most of theaccidents were caused by tower counterattack trip caused by lightning,which had abad impact on the safe and stable operation of power system in Shiyan area.In thispaper,the fault analysis and recurrence of two 220kV transmission lines in this areaare carried out,and the lightning resistance performance of the area is evaluated.Thedifferentiated lightning protection is adopted as the lightning protection criterion,andthe lightning protection strategy is formulated,which has reference significance forreducing the tripping rate of the tower in this area and improving the safe and stableoperation of the power system.This paper describes the work done in the process of lightning protectionassessment,including the calculation of lightning induced voltage on transmissionline tower,the detailed analysis of main lightning parameters,the introduction ofBergeron algorithm and the typical modules of electromagnetic transient softwareEMTP,which provides theoretical support for the analysis and modeling of 220kVtransmission line counterattack accident in Shiyan area.The lightning counterattackmodels of 220kV single circuit and double circuit transmission lines are establishedby using EMTP electromagnetic transient software,and the theoretical reliability ofthe models is verified by data,which is used to calculate the lightning withstand levelof transmission lines.The influence of different factors on the lightning withstandperformance of 220kV single and double circuit transmission lines is analyzed.Thesimulation results show that the phase of power frequency voltage directly determinesthe order of conductor flashover;the most critical factor affecting the lightningwithstand level of tower counterattack is the size of grounding resistance.According