Adaptive battery energy storage system controller for enhancing frequency stability of a low inertia grid

Abstract

Due to the rapid increasing demand of grid connected solar photovoltaic, the overall system inertia decreases and hence causes system instability. Virtual inertia emulation is one of the solution to this low inertia problem that can be done through inverter control and energy storage devices. This thesis presents a simple improved adaptive Fuzzy-ANFIS hybrid algorithm-based BESS controller that can emulate virtual inertia to improve frequency stability of a low inertia grid. The proposed controller has been tested on a low inertia grid for different case studies and a comparative analysis has been done in the last chapter of this thesis. The presented controller eliminates the limitations of conventionally used PI controller and hence an improvement of frequency nadir by 0.43% for sudden load variation and 0.61% for transient short circuit fault have been observed. Moreover, improvement in ROCOF and settling time have been noticed for the proposed controller also.