The software is intended for tender calculations performance, the selection of transformer variant on the base of economic criteria (capitalized value, material costs). The variants to compare are selected considering the limits of paired impedance, losses, masses, transportation dimensions. The program allows simultaneous selection of variants with several restrictions by impedances. TRDO contains extensive base by the standard schemes and windings arrangement allowing by the several clicks fill the input data and after variant selection transfer the data for the verification calculations in the other programs.