According to the relation of power and energy,the flux law which satisfied in line conductor was exended to the closed return circuit of the conductor with section,and some sides should be careful when apply the flux law of the conductor with section.

In DC transmission line construction design,current national standard of economical current density will under predictcd conductor section,resulting in large loss.

In this paper,the mechanism and characteristics of conductor skin effect with nonlinear loads were deeply analyzed;the impact of skin effect on conductor section selection were studied;the existing problems of conductor section selection were indicated;the new methods and conclusions of conductor section selection with nonlinear loads were presented.

Based on design of the first 750 kV line in high altitude area of China as well the overseas requirements of conductor selection and electromagnetic environment, the laws of effect of conductor section and split mode on the electromagnetic environment, mechanical features and project economy of various conductor used in 750 kV single line are introduced.

Singling out lead section from a 10kV distribution line of agricultural electricity network;

Two selection methods of lead section are compared in the paper,and economic benefits of them are also analyzed,in order to reduce line loss with the same investment in rural power grid alteration.

From the point of view of economic integration of construction investment and electricity saving, and through comparison and analysis of the power energy quality, this method carried out optimal selection for wire sectio

In the course of designing buried power circuit, the main project is the wire section selection Providing that the voltage quality is guaranteed, permitted flow can be checked.