The use of multiwinding transformers with synchronous condensers for system voltage regulation

THREE-WINDING transformer banks offer a convenient and economical means, and are frequently used, for operating synchronous condensers at step-down substations, particularly where the secondary voltage is too high for direct operation of the condenser. The usual function of the condenser in such cases is to regulate the secondary voltage, and the condenser regulator is controlled from that voltage rather than from the tertiary winding, or condenser terminal voltage. Furthermore, in many three-winding transformer designs the effect is nearly the same as though the condenser were actually operating on the secondary winding.