What is a Phase Shifting Transformer? – Construction & Working
A phase-shifting transformer is a special type of transformer that can control the active power flow on a three-phase transmission network. It works by changing the voltage phase angle difference between two nodes of the system. This can help to stabilize the power flow and balance the loads in the network.
A phase-shifting transformer consists of two sets of transformers: a shunt unit and a series unit. The shunt unit is connected in parallel with the transmission line, while the series unit is connected in series with the line.
The series unit injects a phase-shifted voltage into the line, which is fed by the shunt unit. The phase shift is induced by the configuration of these two transformers.
The phase shift can be adjusted by rotating the rotor of the series unit, which is similar to an induction motor. The rotor winding is wound on a laminated structure, and it induces an EMF that has a phase displacement according to the rotor rotation.
The phase shift of the emf is proportional to the angle at which the rotor is rotated. A pointer is attached to the top of the rotor, which indicates the angle of rotation and the corresponding phase shift.
A phase-shifting transformer can be classified into different types based on its symmetry, direction, and control mode.