The power distribution system is very important to provide a stable power supply for the community and industry. Therefore, the protection system plays a crucial role in protecting the electricity distribution network from possible disturbances. This study aims to evaluate the performance of the protection coordination system on a 20 kV distribution feeder, as well as whether the protection relay settings are in accordance with IEC and SPLN standards. The method used in this study is mathematical calculation and simulation using DigSilent Power Factory software. Th analysis is carried out by calculating the short-circuit current which is the basis for the relay settings, and the
results of the calculations are simulated using DigSilent Power Factory software to assess the protection coordination in the system. Simulation results show that at a fault point 10% from the source, the short-circuit current is 10.64 kA for a single-phase-to-ground fault, 10.59 kA for a two-phase fault, and 12.23 kA for a three-phase fault. Meanwhile, at a fault point 90% from the source, the short-circuit current decreases significantly to 1.99 kA, 1.72 kA, and 1.99 kA, respectively. The differences in short-circuit current values at different distances demonstrate the effect of line impedance on the magnitude of the fault current.These results indicate that the farther the fault point is from the source, the smaller the short-circuit current. This aligns with the theory that the total line impedance is directly proportional to distance, thus influencing the magnitude of the fault current. This information can be used as a basis for optimal protection settings to maintain system selectivity and reliability.