The Enhancement of Power System Stability Under Different Fault Conditions (East Java-Bali 2018 Blackout)

The Java-Bali power system is the biggest power system in Indonesia. On September 5th, 2018 at 11:26 AM, a region in the East Java-Bali subsystem suffered a blackout due to a single line to ground fault that disrupted the stability of the interconnected system and caused cascaded tripping.

This thesis presents the results of an evaluation of the dynamic performance of the East Java-Bali subsystem. It involves the static and dynamic simulations of the sequence of events that led to the East Java Bali subsystem blackout, especially the impact of the loss of a set of 500 kV transmission lines, which in reality was suspected to be the main cause.

The basic calculations related to power system state and familiarization with PSS/E (a commercial power system analysis software package) are first demonstrated. A simple 3-bus system test is taken as an example. The steady state characteristics of the active and reactive power injection, voltage and phase angle are calculated manually and compared to the PSS/E simulation results. As for the dynamic characteristics, short circuit current, electrical and mechanical power, rotor angle, and fault clearing time are determined by observing the plots of the simulation results. Based on understanding of the PSS/E modeling and simulation, the configuration, generation, and loading of the simplified East Java-Bali subsystem is evaluated. The generators (including the excitation system and governor) and transmission lines parameters are updated, as the reference model for the study. The model is validated by the actual data (active power flow) before the fault. Single line to ground fault and loss of generation disturbances were simulated to observe the stability of the system.

The analysis of the blackout is conducted through the simulation results based on all relevant documentation (such as fault report and sequence of events). With respect to the sequence of events (a single line to ground fault on the 500kV transmission lines, overload on 150kV transmission lines and tripping of power plants), several simulations of the East Java-Bali subsystem operations provided in the official blackout report are evaluated. Finally, the undervoltage load shedding strategy is evaluated and proposed as a solution to mitigate the blackout in the East Java-Bali subsystem.

The simulations reveal some interesting results regarding the operational characteristics of the East Java-Bali subsystem before the disturbances and during the cascaded tripping.