[en] A simplified method for power losses calculation in grounding wires of 400 kV lines, i.e. lines with two grounding wires, is presented in this paper. Following the conclusions of the detailed losses calculation based on the multi-phase admittance summation method of [1], the grounding system of these lines can be equivalized by one loop grounded only in two points, at the substations at both ends of the line. Consequently, power losses can be calculated by solving a simple system of two linear equations. Numerous tests were performed and the results compared with those of the multi-phase admittance summation method [1]. In this paper such comparison for the 400 kV line Bitola 2 - Skopje 4 is presented. This comparison shows explicitly that the proposed simplified method gives a very good approximation for the power losses with an error less then 1 % in the crises when the line is loaded with more then 100 MW, which is a common case for 400 kV lines. (Original)