An improved adaptive hybrid controller for battery energy storage system to enhance frequency stability of a low inertia grid

Abstract

Despite the promising dynamic characteristics of battery energy storage system (BESS) for efficient and reliable use in stability enhancement of a low inertia grid due to the large-scale integration of renewable energy sources (RESs), existing BESS controllers are found to be complex, inefficient and less responsive to adapt any changes in frequency of the system. This paper presents a simple improved adaptive Fuzzy-ANFIS hybrid algorithm-based BESS controller. The proposed controller can emulate virtual inertia by controlling the active power flow to improve frequency stability i.e. frequency nadir and rate of change of frequency (ROCOF). Necessary modeling of the controller was carried out and its performance has been analyzed to evaluate the performance of the controller. With different case studies and comparative analysis, the controller has also demonstrated its potentials to improve the frequency nadir by 0.43 % for sudden load variation and 0.61 % for transient short circuit fault. The promising performance of the controller suggests its utility for better grid inertial support to a low inertia grid. Additionally, due to the improvement in ROCOF and settling time, the proposed controller thus can increase the overall inertia in addition to the power balance at point of common coupling (PCC).