Modeling and control of thyristor controlled phase shifting transformer

Aiming at the two-core symmetric discrete thyristor controlled phase shifting transformer (TCSD-TCPST), its modeling and control strategies are studied in this paper. Firstly, the mathematical model of TCSD-TCPST considering its equivalent impedance is deduced. And the relationship among phase-shifting angle, tap position and equivalent impedance are derived. Then, two control strategies of TCSD-TCPST with different control objectives, phase shifting angle and active power, are proposed. Finally, Simulation results based on PSCAD/EMTDC show that the mathematical model can accurately reflect the steady-state characteristic of TCSD-TCPST on different tap positions and TCSD-TCPST can both quickly response to changes of control objectives when adopting two different control strategies.