Isolated Hybrid System Protection Performance: A Study Case in Island S

Hybrid of conventional fossil fuel and intermittent generations have been general practices in isolated system either operated on-grid or off-grid. Their impacts on system operation and behavior during the disturbance have to be considered carefully in order to assure the availability and the reliability of service. Study case on a radial network protection performance were carried out on a 70 kWp PV or approx. 6.5% penetration combined with 1080 kW diesel combustion engine installed capacity to serve 439 kW peak-load in a particular sparse populated island. Protection systems mainly rely on non-adaptive overcurrent relay schemes to secure the ground to phase or phase to phase faults. Black out (BO) in distribution system were recorded as 7 of 16 faults in 2023 and 5 of 5 up to April 2023. A line differential current protection scheme and a coordinated directional overcurrent protection scheme are proposed to improve the performance align with the planned improvement of the system to prevent the BO occurrences.