Icing Disaster Analysis And Retrofit Scheme Of Transmission Line In Southern Hebei Power Grid

500kV high voltage transmission network(HV)is the main network frame of the southern Hebei power grid.It is responsible for the transmission of electric energy between various cities and the distribution of electricity to the vast number of power supply users.It is closely related to the people’s production and life.The most ideal condition for transmission lines is that no failure or outage will occur in any case.However,according to incomplete statistics,the 500 kV line fault tripping in Hebei southern power grid is more than 20 times a year,and there are as many as more than 300 tripping failures below 220 kV.This shows that our power network has not reached a very high level of security and stability.The line is erected in the field,which is greatly influenced by natural disasters.Some lines are in the area of open field and mountain area.Once the fault tripping,the recovery work of the fault point is often difficult to carry out.In 2015,many 500 kV lines such as Dafang II and third line were iced and collapsed,which also caused a great response nationwide.This shows that the southern Hebei power grid has some deficiencies in dealing with sudden ice cover natural disasters.Due to the shortage of the super El Nino phenomenon and the anti icing capacity of the line,the ice coating and the tower falling are caused.Therefore,it is of great significance to enhance the ability of 500 kV Dafang II II line,Luxin II line and other lines to resist icing and improve their ability to fight natural disasters.This paper focuses on this problem.The main work and achievements are as follows:1.The cause of ice falling tower of 500 kV large room II line is analyzed.The first is the super El Nino phenomenon.The two is that the anti ice ability of the line is insufficient.At the same time,the process of weather development,meteorological parameters and icing conditions in the period of ice damage fault are combined.At the same time,the icing conditions of micro terrain and micro meteorology such as mountain area,hilly and mountain depression are also refined.The distribution map of ice area of Hebei South Network in 2016 was reformulated.2.Through analysis and comparison,it is concluded that the "ice section" transformation of ice resistant lines is a suitable way of transformation.The power outage time is relatively short,which brings the risk of channel operation less.At the same time,it also improved the ability of icing resistance of large housing lines,and the investment budget was relatively rational.The reform method is determined,and the revised ice area distribution map is combined,and the tower body,insulation coordination and so on are recalculated,and the reform scheme is put forward.3.On the basis of the opportunity of blackout,the reconstruction of the field has been carried out.The actual construction shows that the transformation plan is feasible.Line conductors,ground wires and optical cables need to be compensated.Other construction measures basically conform to the normal standardized operation management process.The deficiency in the reform scheme is also found through transformation.The biggest difficulty lies in the deviation of the bolt hole distance between the new and old tower materials in the tower reinforcement,which leads to the slow construction progress.This will be avoided in the transformation of other lines in the future.