Closed grids inherit the main qualities of twoterminal lines. In closed grids, as opposed to the radial, except for the load power losses, may be extra losses from grid nonuniformity (X/R ≠ const) and from voltage difference in some nodes. To eliminate extra losses, it is necessary to know where in the grid they appear and how great they are. This can be made by decomposing the losses. To do this, the initial grid should be converted to uniform (or in R-grid) one without loop emf (if such are in the initial grid) and calculate load losses in this grid, calculate extra losses in initial grid caused by joint action of circulating currents from grid non uniformity and equalizing currents from loop emf; the sums of these currents (called extra currents) is orthogonal to load branch currents in uniform grid in the sense that the sum of power losses from separate action of load currents in uniform grid and of extra currents (extra losses) in initial grid are equal to power losses in the initial grid. Any grid can be converted to uniform one. Different transformation ratios of high voltage transformers can increase the losses.