特高压交流输电线路电气不平衡度及换位研究

Research on Electrical Unbalance and Transposition of UHVAC Transmission Lines

架空输电线路各相导线参数的不一致,导致了系统中电流和电压的不对称,必须结合导线换位来减小线路不平衡度。基于电磁暂态软件ATP-EMTP,搭建了适用于1000kV特高压交流输电线路的仿真模型,并结合Matlab软件进行编程计算,研究了双回输电线路的电气不平衡度及其影响因素。提出了1000kV输电线路电压不平衡度满足要求值的换位方式,对于武汉—南京—长沙1000kV特高压交流输变电工程线路,在武南段进行一次全换位,南长段进行一次全换位,即可满足不平衡度限制的要求,换位后电压不平衡度低于0.66%。

The inconsistent parameters of three-phase overhead transmission line lead to the asymmetrical current and the asymmetrical voltage in power system,so it is necessary to change the position of the wire to reduce the unbalance.Based on ATP-EMTP,a 1000 kV UHVAC transmission line model is established,and combined with Matlab software for programming calculation,the factors affecting the electrical unbalance of double-circuit transmission lines are studied.The transposition method for voltage unbalance of 1000 kV transmission line which meets the required value is proposed.For Wuhan-Nanjing-Changsha 1000 kV UHVAC transmission and transformation engineering line,the Wuhan-Nanchang section will be fully transposed as well as the Nanchang-Changsha section,which can meet the requirements of unbalance limit.After transposition,the voltage unbalance is less than 0.66%.