Research On Imbalance Of 220kV Double-circuit Lines On The Same Tower In Jiangxi

With the development of economy in our country,power demand has been increasinglygreat.So some problems appear in power grid especially in developed area,such as shortageof transmission capacity,lack of transmission line corridors and so on.In order to increasepower transmission capacity and corridor use efficiency,double-circuits transmission line is aninevitable choice of power system development.Despite of their advantages,double-circuit lines on the same tower bring up with new challenges for the power system as well.A serious three-phase imbalance occurred recently in a 220 k V double-circuit transmissionline of Jiangxi grid,which may threat the stable operation of the power system,andandit is necessary to do some researches on three phase current imbalance phenomenon in jiangxi power grid.First of all,the research of three-phase imbalance results which was got from chinese or foreign investigate were introduced in this dissertation.On the basis of power system analysis software package,the research linewas studied on ATP-EMTP simulation modeling.In the next step of research can be divided into two parts.On the one hand,the reason may cause 220 k V with double-circuit transmission line on same towers are not balance was investigate,such as: conductor transposition and replace phase sequence arrangement,different types of tower,ground and sag on the influence of the three phase current balance;On the other hand,According to the specific reason,measures to improve the imbalance problem was present,the simulation example and evaluation were used to verify its effectiveness,which werealso appliedin the other power supply company for further validation.For phenomenon of three phase current imbalance of jiangxi power grid in 220 k Vtransmissionline,this dissertationuesd the ATP-EMTP to model 220 k V transmission line with double towers of jiangxi power grid transmission,and calculating the simulation of unbalance current,at the same time,finding out the main reason that cause appearance of unbalance current of 220 k V power grid when the data was compared.Through the investigate of the unbalance of jiangxi power grid 220 k V with two-loop towers,the jiangxi power grid of 220 k V line current imbalance problem can be improved,furthermore,the results can also be used for engineering design of transmission lines or provided the necessary reference foundation.