In this paper, a load frequency control (LFC) of high voltage direct current (HVDC)-linked interconnected multi-area power system (MPS) is presented. The control scheme is aimed at maintaining a near-zero steady state errors for deviation in frequency and inter-area power flow within acceptable limit in a three-area MPS. The proposed LFC was realized with aid of proportional integral (PI) controller designed in a decoupled form and a supplementary power modulation controller (SPMC). The SPMC regulates flow of DC power through the DC-link. The PI controllers are optimized based on integral square error (ISE) using quasi-oppositional whale optimization algorithm (QOWOA). The efficacy of the proposed LFC scheme was demonstrated through time-based simulations in MATLAB/Simulink environment. The system responses are compared with those obtained in conventional AC system. The comparative analysis revealed the superiority of the developed QOWOA-optimized HVDC-linked over the conventional AC system. The overshoot and settling times of frequency deviation and tie-line powers are used as the performance metrics.
Key words: Load frequency control, HVDC, supplementary power modulation controller, whale optimization algorithm
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