Impact of Battery Energy Storage System Penetration on UFLS Scheme in NTT Electrical System

Under Frequency Load Shedding (UFLS) works due to system instability due to loss of generation power which impacting the system's frequency. In order to reduce the amount of load shedding during UFLS scheme, Battery Energy Storage System (BESS) technology is employed. This study aim to identify if BESS could effectively improving system stability and reduce amount of load shedding during disturbance period. The disturbance scenario is done by releasing Generators in East Nusa Tenggara System to trigger UFLS scheme. Using 8 different cases, the case which the system is equipped with BESS showing a significant stability improvement. For instance in Case 3, which releasing 15 MW of generator, the nadir frequency without BESS penetration is 48,687 Hz and trigger the UFR Stage 3. While using BESS could keep the nadir frequency in 48,932 Hz and only trigger stage 2 UFR. The result of the simulation shows that the frequency stability is improving, and number of load shed could be reduced in a system with BESS compared to non-BESS equipped system.