Simulation and Analysis of Transient Stability in the Electrical System of PT. Semen Indonesia Aceh

Abstract

PT. Semen Indonesia is a state-owned company that is a well-known cement producer in Indonesia and plans to build the Semen Aceh factory. The Semen Aceh factory’s electrical system utilizes two power sources: Alternative Electrical System 1 relies on PLN sources, while Alternative Electrical System 2 uses a 30 MW generator and two 25 MW generators. Therefore, it is necessary to conduct a transient stability analysis—including voltage stability, frequency stability, and rotor angle stability—during generator outages, motor activation, and short-circuit disturbances. The simulation results for alternative electrical system 2 indicate that generator disconnection causes system frequency instability. In a short-circuit situation at the 0.4 kV voltage level, the impact on stability is not significant, even though it causes a momentary voltage drop that subsequently returns to normal. Meanwhile, in the case of a short circuit at a voltage level of 6.3 kV, each voltage level value decreases following a three-phase short-circuit fault; however, after the disconnection of CB5-831MV081, the instantaneous voltage value rises to 108.35% and subsequently stabilizes at 97.08%. In the case of motor activation, the lowest voltage drop reached 65.78% and then stabilized at 91.46%.