Phase Angle Regulator (PAR)

A specialized transformer that deliberately introduces a phase angle shift between its input and output voltages to control the direction and magnitude of real power flow on a transmission line or between parallel transmission paths. Without PARs, power on parallel paths divides inversely proportional to impedance, often causing some lines to be thermally overloaded while others carry less than their share. By inserting a controllable phase angle, the PAR redirects power toward underloaded paths, improving overall system utilization and preventing inadvertent overloads. Also called a Phase-Shifting Transformer (PST).

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