Study of Voltage Stability Impact From Solar Power Plant and Battery Energy Storage System Integration into Rote Island's Distribution System

In the 2021-2030 National Electricity Supply Business Plan by the National Electricity Company of Indonesia (PT PLN), a solar power plant with a capacity of 3.2 MW is scheduled for construction on Rote Island in 2025. When integrating solar power into the grid, selecting optimal locations is crucial to minimize system losses. One key aspect to consider is voltage stability. This study aims to identify the optimal installation sites for the solar power plant on Rote Island. Additionally, a Battery Energy Storage System (BESS) is incorporated into the system to manage peak load demands during nighttime. Simulations were conducted using DIgSILENT PowerFactory software. The optimal locations for the solar power plant and BESS were determined based on the highest voltage sensitivity at feeder bus points. The installation of the solar power plant and BESS will be divided into two scenarios: the first scenario involves 2 locations (centralized solar power plant), and the second scenario includes 20 locations (distributed solar power plant). Simulation results for the 334 buses in the Rote Island distribution system indicate that the latter scenario, involving 20 distributed locations, is more optimal. This configuration significantly reduces the voltage sensitivity at bus 503 of the Labunggasa feeder from 0.005114 pu/MW to 0.004384 pu/MW. Moreover, through the PV curve, voltage stability is further analyzed. The power transfer capacity (P collapse) to these buses before a voltage collapse occurs increases from 4983 kW to 6,848 kW at bus 503 and from 4,223 kW to 5,265 kW at bus 60. Lastly, through a 24-hour quasi-dynamic simulation, the voltage profiles at these buses are further evaluated, demonstrating an increase in voltage from 0.9271 p.u. to 0.9613 p.u. at bus 503 and from 0.9483 p.u. to 0.9718 p.u. at bus 60 during peak load conditions after the integration of the solar power plant and BESS.