Adaptive Controller Based Unified Power Flow Control for Low Power Oscillation Damping

Low frequency oscillation (LFO) within a power system is an important issue. Loss of inter-connected machine synchronism, reactive load increase, and faults and disturbances lead to a LFO in a range between 0.1–2 Hz. LFOs limit power transfer over long transmission lines, thus degrading the quality of supply. Moreover, conventional local control, namely, the power system stabilizer, is unable to mitigate LFOs. Furthermore, continuation of LFOs will lead to complete system collapse (blackouts). Considering the above issues, there is a pressing need to incorporate advanced control systems to damp inter-area LFOs. We propose an adaptive-supplementary unified power flow control (UPFC) for two inter-connected areas of a power system. Our work is novel in its design of a supplementary control system using a neural network based on a feedback linearization auto-regression average model. With the above proposed control scheme, the stability of power system is enhanced in terms of: (1) effective LFO damping; (2) power transfer; (3) improvement in the dynamic parameters of the system; (4) active and reactive power support; (5) loss minimization; and (6) demand–supply management. To justify these claims, we implement our proposed controller on a two-area (four machine) system. Critical analysis of the system is conducted under symmetrical grid faults. The result of the proposed control scheme justifies the performance enhancement of above parameters, as per grid-code requirements, compared with conventional a proportional integral (PI) controller.