Investigation on Grid-Scale BESS Capacity for Frequency Support under various System Inertia

Abstract

Rapid growth in the renewable energy sector supplying to the grid including solar PV and wind has caused the system inertia to reduce. Consequently, instability problems and supply interruption will happen more frequently during power imbalance in a low inertia power system. Hence, the solution of implementing a grid-scale battery energy storage system (BESS) is proposed to provide frequency support to the grid. This paper presents the modelling of the 565 MW Eastern Region of the Peninsular Malaysia power system in MATLAB/Simulink, where the frequency response of the system under power disturbances is studied and the minimum BESS capacity required for frequency support is investigated. The effect of frequency support with and without BESS implementation is also investigated under various system inertia. Comparing the frequency nadir of the system with and without BESS, the results show that under the largest disturbance of 300 MW, which is 53% of the 565 MW system and the lowest inertia of 2s, the 300 kWh BESS supported the frequency by increasing the frequency nadir up to 0.024 Hz. The results show trends in which the BESS will contribute more to systems with lower inertia value and larger disturbance during frequency support.