ABSTRACT
Phase-shifting transformers are used in power systems to help control power flow and line losses. They shift the input voltages and currents by an angle that can be adjusted using a tap changer. For three-phase transformers, the quadrature voltage to be added to a given phase voltage can be derived by interconnecting the other phases, which can be done in many ways; this gives rise to a large number of configurations for these transformers. This chapter deals with only a few common types of configurations. It illustrates the use of phase-shift transformers by considering the feeding of a common load from two voltage sources that are out of phase with each other. Phase shifters for large power applications are often designed as two units—the series unit and the excitor unit, each with its own core and associated coils. The chapter analyses a delta HV (H) winding and zig-zag low-voltage (X) winding transformer.
