Analysis On Electromagnetic Transient Steady State Characteristics In UHV Six-Phase Transmission Lines

The present situation of the electric power industry is energy uneven distribution, electric power load demand to soar, environmental protection and high land use fee and so on various pressure.Theory research on electromagnetic transient steady state characteristics in UHV six phase transmission lines will be on the basis of applying six phase transmission in UHV power grid.According to typical tower size of the UHV six phase transmission, this paper first calculates line phase parameters of the six phase transmission in transposition and complete transposition two cases,then divides six phase transmission into two symmetrical three phase system, uses the same method,and calculates the line phase parameters and the corresponding line sequence component parameters in the complete transposition case.Secondly, use six sequence symmetrical component method and line sequence component parameters, calculate the terminal voltage and current of no fault phase(s) in the six phase transmission line in all sorts of terminal asymmetric fault in the failure time.According to the uniform transmission line knowledge introduced in the theory of circuit, calculate the line voltage distribution of the no fault phase along the line.And, using EMTP soft to simulate asymmetric fault of six phase transmission line,record the line voltage distribution of the no fault phase along the line and tabulate,compare with calculated results of the MATLAB software.Then, analyze the characteristics of closing no-load operation of the line overvoltage, use EMTP soft to simulate the cases of switching the no-load line in six phase transmission line, and compare with the line voltage distribution of the no fault phase along the line.Finally, on the premise of tower size mentioned in this paper,contrast the power transmission characteristics analysis of UHV six phase transmission with that of double circuits transmission lines on the same tower,and analyze the electromagnetic field characteristic1m above the ground between them.Refer to the construction costs of750kV line project from Guanting to the east of Lanzhou,estimate construction costs of UHV six phase transmission,compare with unit distance conveying unit electric power construction cost of1000kV UHV ac transmission pilot project of Jin Dongnan-Nanyang-Jingmen.