Adaptive stabilizing control of a power system through UPFC shunt and series converters

The dynamic performance of a power system can be improved by using additional controls in a unified power flow controller (UPFC). Self-tuning adaptive control of the voltage magnitude of the series converter and phase angle of shunt converter for stabilization are considered in this article. From the input-output data record, a linear plant model of the UPFC is identified through a least square regressive algorithm. Stabilizing control is derived for the identified model through a pole-shifting technique. Simulations have been carried out for a range of operation with various disturbances. While both the controls are effective in stabilizing the system, the shunt converter phase angle control was observed to be superior. Responses were compared with optimized PI control and robustness of the proposed adaptive algorithms was tested.