PSS Optimal Placement For Damping Ratio Improvement Through Small Signal Stability Analysis in Kalimantan Interconnection System

The interconnection system of Kalimantan (Barito & Mahakam) has a transmission length of 5124 kms and is dominated by radial transmission. Therefore, the issue of system stability is significant, especially the location of the power plants far from each other. The interconnection system has an inter-area oscillation mode with an oscillation frequency value between 0.595 Hz - 0.7069 Hz with a damping ratio between 0.998% - 1.985%. Based on the simulation and analysis, the Kalimantan interconnection system does not have an oscillation mode with a negative damping ratio value. Still, there is a potential for oscillations with a low damping ratio (< 5%), so it is necessary to study the addition of PSS (Power System Stabilizer) to the generator to improve the damping ratio in the system. The most optimal location for the PSS to increase the damping ratio is at PLTU SLK and PLTU GPK. The location of PSS at PLTU TPI does not significantly impact inter-area oscillations. Still, it contributes to improving the damping ratio in the intra-area mode. A minimum number of PSS is required at PLTU SLK and PLTU GPK to meet a more than 10% of damping ratio. The best damping ratio values for both inter-area and intra-area modes were obtained with PSS locations at PLTU SLK, PLTU TPI, PLTU GPK, and PLTU Indoeka (inter-area damping 16.1% and intra-area damping 14.37%).