Optimal feedback path selection for interconnected power systems using load frequency control strategy

Abstract

The main goal of an interconnected power system is to transfer power from one area to another while the network frequency and tie-line flow remain within the prescribed limits. However, both of these quantities may violate their desired values during this transfer due to disturbances in the network. This paper proposes a stratagem for choosing the right feedback path for an interconnected power system to maintain the system frequency and tie-line flows within the prescribed limits while external disturbances exist. Area control error (ACE), a combination of frequency error and tie-flow deviations, is used as the performance indicator. In the proposed approach, feedback control is designed using active disturbance rejection controller (ADRC) based load frequency control to tackle ACE. It is observed that the individual load change monitoring is sufficient for selecting the right feedback paths rather than the consideration of simultaneous load changes of all load centres. The effectiveness of the proposed controller for selecting the feedback paths has been tested by conducting several case studies. The results demonstrate that the proposed controller can reduce transient magnitude around 57% for ACE, 55% for frequency error and 72% for tie-line error as compared to the PID controller.