Hierarchical Structure-based Ramp rate Control of Renewable Energy Sources for Hub-Station

Abstract

A hierarchical structure-based ramp rate control using MPC (Model Predictive Control) to mitigate fluctuation of renewable energy sources and control HESS (Hybrid Energy Storage System) for Hub-station is proposed. As a key factor in the next-generation power grid systems, the structure and components of the hub station are proposed. Not only operating the hub-station stably but also increase the penetration rate of renewable energy sources, the hierarchical structure-based ramp rate control is necessary. It consists of an upper and lower-level control strategy. In the upper-level control strategy, the ramp rate control and frequency decomposition are conducted. And in the lower-level control strategy, Using the MPC technique, both SOC and power reference of the battery can be controlled. Fast and high-frequency output fluctuation components can be handled by the supercapacitor control strategy, and it supplements the power deviation from the battery control strategy as an auxiliary device. Through the proposed technique, the output fluctuation of the renewable energy source can be controlled within the limit value, and at the same time, the charge, discharge power, and SOC value of the HESS can be controlled within the specified range.