FIELD: power electronics. SUBSTANCE: voltage regulator designed for phase-by-phase control of three-phase voltage at low-voltage side of transformer substation incorporating provision for reactive power correction has two frequency changers one of which incorporates DC (three-phase/single-phase) section and other one is directly coupled and naturally changed over from three-phase to single-phase supply and vice versa. Single-phase high-frequency step-sown transformer inserted between them has center tap of its secondary winding connected to load or to additional power supply and its output is inserted in series with star-connected secondary winding of substation main transformer. Three-phase voltage is regulated with aid of rectifier and balanced out by means of thyristors of phase groups of frequency changer. Other proposed design versions do not consume reactive power or incorporate provision for its frequency-controlled or fully automatic correction. EFFECT: simplified design and reduced weight of device due to introduction of high-frequency section. 5 cl, 4 dwg
