Dynamic Surface Sliding Mode Control-Based LFC Design for RES-Dominated Power Systems With a Provision of Grid-Scale Virtual Energy Storage

Massive penetration of renewable energy sources (RES) leads to a decline in overall inertia, making the system more vulnerable to unforeseen scenarios. Although energy storage can be a viable solution for addressing the low inertia grid, it is an expensive option. To address this issue, grid-scale virtual energy storage (VES) concept is utilized in this paper which gathers free energy storage from features intrinsic to the regulation of a multi-area grid, thus permitting the greater integration of RES without compromising the system's frequency stability. The VES acts as a virtual energy storage system, leveraging the existing diversity in area control error (ACE) and implementing an effective frequency regulation strategy. To minimize ACE, this paper introduces a novel dynamic surface sliding mode control (DSMC) technique in the secondary loop for load frequency control of time-delayed power systems, capable of handling both matched and unmatched disturbances. Although the design procedure of DSMC resembles those of the backstepping SMC, the devised controller effectively addresses the issue of “explosion of terms”. Various case studies validate the superior performance of DSMC and its stability is assessed based on Lyapunov Theory. The robustness of the proposed scheme is validated against uncertain parametric variations and N-1 contingency.