In this paper classified are the technical losses by types. Examined and analyzed existent are the methods of calculation of conditionally-constant and loaded losses in the air lines of electrical transmission of common function. On the basis of the minimum relative energy losses obtained is a new objective function, conducted is optimization of the total comparative electrical energy and determined are the current minimum losses in lines . To motivate consumers and supply companies to provide the optimal planning and implementation of energy saving measures as a standard of technique electrical energy loss, it is recommended to adopt value relative losses applicable to this current. Conducted is the factor analysis of changes in relative energy losses depending on variable parameters and technical characteristics of a given transmission line.