An improved Rao algorithm for frequency stability enhancement of nonlinear power system interconnected by AC/DC links with high renewables penetration

In this paper, an improved optimization algorithm is proposed to overcome the original Rao algorithm limitations (i.e., different characteristics in exploration and exploitation) and enhance the performance of the original Rao algorithm. In the improved algorithm, the self-adaptive multi-population and Levy flight methods are utilized in the original Rao algorithm. The improved algorithm is called I_Rao_3. The improved algorithm’s efficiency is confirmed by comparing it to the original Rao algorithm utilizing various standard benchmark test functions. Moreover, the proposed I_Rao_3 algorithm is utilized to improve the frequency response in a hybrid renewable power grid by fine-tuning the proportional-integral-derivative (PID) controller parameters. The targeted system used for this study is a hybrid power grid, which encompasses conventional generating stations (i.e., thermal power plants), renewable power stations (i.e., PV and wind power stations) for the analysis of the load frequency control (LFC) issue. Unlike other previously published works, this study considers the impact of DC links in parallel to AC links to interconnect the two-hybrid renewable power system area. In addition, the nonlinearities effects (i.e., generation rate constraint and a governor dead band) are applied to each area in order to achieve a more realistic study. The superiority of the proposed PID controller-based I_Rao_3 algorithm is endorsed by comparing its performance with many other optimization algorithms.